Final Report Summary - BLUESHIP (Electrospun functionalized nano-materials for ultra-compact de-NOX SCR system in naval shipping)
Executive Summary:
The marine industry represents a competitive and strategic sector for Europe. With a market share of around 15% in volume terms, Europe is still at the top (with South Korea) for global leadership in terms of the value of civilian ships produced. For this reason, the European Commission has adopted in February 2013 the LeaderSHIP 2015 initiative, defining a strategic vision for the industry (innovative, green, specialized in high tech markets, energy efficient, diversifying into new markets etc.), with particular focus for maritime research towards zero emission and energy efficient vessels. In fact the volumes of waterborne transport are rapidly increasing and now account for close to 50% of intra EU of freight volume (DG TREN Data). Under current growth trends, emissions from international shipping in European sea areas are projected to increase by nearly 40% between 2000 and 2020. If no additional abatement measures are taken, by 2020 the emissions from shipping around Europe are expected to equal or even surpass the total from all land-based sources in the 27 EU member states.
NOx emission standards for international shipping are set by the International Maritime Organization (IMO). New regulations were introduced by the IMO in 2008 (MARPOL Annex VI): the IMO Tier III requirements reduce nitrogen-oxide emissions (NOx) by approximately 76% in comparison to a Tier II engine and applies to new vessels and engines built after 1 January 2016 when sailing in Emission Control Areas (ECAs). This poses a significant challenge to engine designers, as they need to apply NOx-reduction measures.
The only technology that presently allows to comply with TIER III is Selective Catalytic Reactor (SCR), presently equipped with a catalyst bed realised through honeycomb monolithic units. The monolith is manufactured by extrusion technique starting from ceramic-polymeric blends generally with use of pore-formers.
The BLUESHIP project aims to realize an innovative de-NOx SCR specifically tailored to the shipping industry, based on electrospun ceramic fibres tailored in designed textures modules, meant to replace the existing monolithic honeycomb design, granting reduced size and weight of the system, installation and operational costs, when compared to the state of the art technologies.
The specific objectives of the project were:
• Synthesis and fabrication of V-W-TiO2 fibres in different morphologies and functionalization,
• Characterization of the materials with respect of the De-NOx reaction,
• Modelling of the fluid dynamic inside the reactor and optimization of the design,
• Design of the reactor concept,
• Optimization of electrospinning deposition technology for production of functionalized catalyst fibres,
• Implementation of a pilot application and testing in a test bench,
• Validation of the technology and evaluation of scalability.
The consortium of the BLUESHIP project is composed by the following SME partners: STOGDA Ship Design and Engineering Spz.o.o from Poland; AKRETIA GmbH from Germany, LINARI Engineering Srl from Italy, and the following RTD centres: Labor Srl from Italy, Danmarks Tekniske Universitet from Denmark and Next Technology Tecnotessile from Italy.
Project Context and Objectives:
According to the work plan outlined in Annex I of the Grant Agreement, the BLUESHIP project has been devoted to achieve the following strategic goals:
• S.01 – Reduce the size and the weight of the De-NOx SCR by 50% with respect of the state of art SCR; for installation and retrofit in existing ships, and for possible integration into De-SOx units;
• S.02 – Reduce the consumption, need of purchase and costs of reactants (ammonia or urea) of 20%;
• S.03 – Reduce the installation costs by 20%;
• S.04 – Reduce the operation and maintenance costs of 15%.
The following operative objectives have been pursued to achieve such goals:
• O.O.1 – Synthesis and fabrication of TiO2, V2O5 and WO3 fibres in different morphologies and functionalization;
• O.O.2 – Characterization of the materials with respect of the DeNOx reaction;
• O.O.3 – Modeling of the fluid dynamic inside the reactor and optimization of the design;
• O.O.4 – Design of the control system for optimal operation of the reactor;
• O.O.5 – Optimization of the electrospinning deposition technology for production of functionalized catalyst fibres;
• O.O.6 Implementation of a pilot application and testing in a test bench;
• O.O.7 – Validation of the technology and evaluation of the scalability.
The BLUESHIP project ultimately aims at implementing a compact, light and efficient De-NOx SCR specifically tailored to the need of installation or retrofitting on board of ships, to be integrated with state of the art De-SOx for a complete exhaust treatment and emissions abatement.
The project is expected to generate the following tangible results, available to the SME partners for exploitation:
1. Optimised synthesis, fibre network patterning of functionalized fibres by electrospinning techniques for SCR,
2. Fluid dynamic simulation model and optimised design of the electrospun SCR for shipping application;
3. Optimised production process of functionalized catalytic fibres through electrospinning for the SCR application, and
4. Prototype of the BLUESHIP SCR and results of testing.
The proposed technology is expected to have several advantages for the end-users, among which the most valuable have been considered the reduction in the size of the system meeting the current space demands on board, the integration of De-NOx into De-SOx plants to implement a complete exhaust gas treatment device, increase of the mechanical strength due to reinforcement of catalysts materials and the reduction of transport and purchase costs sustained for urea/ammonia in existing devices.
The project activities have been defined to reach an easy and effective structure:
WP1, WP2, WP3 and WP4 – RTD activities
WP5 – DEMO activities
WP6 – OTHER activities
WP7 – MNGT activities
The project work led to the following main results:
1. Selection of a reliable and effective synthetic method for production and low control process conditions of V-W-TiO2 fibres to be used for the Selective Catalysis Reaction of NOx, reporting their characteristics in terms of morphologies and chemical compositions, as well as assessing their catalytic performance at lab scale SCR;
2. Definition of a solution for the support of the electrospun fibres for the implementation of the catalytic module and of the SCR reactor, testing and characterising their fluid-dynamic permeability;
3. Dimensioning of the BLUESHIP SCR for the target marine application specified in the first stage of the project;
4. Verification through specifically designed simulation model of the pressure losses, gas velocity and the yield of reaction inside the dimensioned reactor.
5. Design and implementation of a pilot scale BLUESHIP SCR prototype equipped with specifically realized catalytic filters realized with nanofibers deposed over corrugated /plain metal sheets representing the selected rolled filter configuration; installation of a test bench facility for the evaluation of the performance on an automotive diesel engine;
6. Field testing of the prototype, assessment the results and definition of plans for future steps required to achieve a more reliable proof of concept were defined, identifying a possible alternative route for the implementation of the BLUESHIP SCR using self-standing catalytic mats realized with the nanofibers, instead of metallic support for deposition.
7. Identification of the electrospinning technology to be used for the production at pilot scale and needless, to be fully exploited for the production scale-up and optimization of the process parameters to ensure the best production of the nanofibres morphology (no or minor defects);
8. Conduction of a technical-economic analysis of the efficiency of the catalytic nanofibers and their production costs through the scaled up industrial method implemented, assessing the industrial feasibility of the production.
9. Implementation of the dissemination plan and IPR protection strategy, including patenting of the method for the synthesis of the fibres and definition of a joint exploitation approach to be followed after the end of the project.
Project Results:
--------- WP1 - DEFINITION OF SPECIFICATIONS (STOGDA)---------
The first work package of the project was dedicated to the collection and the definition of the user requirements for the BLUESHIP project and the definition of the technical specifications and a preliminary layout of the final system. This work package started at month 1 of the project, being planned to last 3 months, in order for all partner to gather all the necessary information related to the user-requirements and the definition of the system specifications. The specifications will then be used to guide the research and the design activities and to assess whether the system that will be developed in the project meets the established requirements. This work package is concluded with the submission of the deliverables foreseen by the work plan.
IDENTIFICATION OF REQUIREMENTS
This activity was mainly carried out main by the SMEs (STOGDA, AKRETIA and LINARI), who identified a complete set of requirements and constraints from the end users side for the implementation of the SCR system, the nanofibres and the electrospinning process requirements. This in order to define the initial framework and targets of the project and put the basis for the definition of the technical specifications and components outline.
In particular, the main result of this activity was the identification of:
o The Regulatory Framework, defining the current EU and International regulations, especially focused on the MARPOL convention, that impose limits of emissions to the marine industry, in order to protect the environment. This is a relevant point for the project, being this regulatory framework the main driver for the need of the BLUESHIP technology.
o The benchmark for the SCR technology, with identification of existing technical solutions, limits and constraints, to be considered as technical and economical reference for the BLUESHIP solution.
o User requirements and external constraints for the implementation of the new SCR system, with selection of the target vessels, motor, oil, exhaust gas cleaning system for BLUESHIP.
o Requirements for nanofibres and electrospinning process, with selection of the manufacturing process, currently applied machinery, and the manufacturing of the nanofibres, which implies the best precursor selection for new SCR system, nanofibres morphology and patterns choices and selection, as well as its costs overview.
The SME have joined their visions and experience to define the different aspects of the requirements for the integration of the SCR system, the nanofibres and electrospinning process.
The technical discussions established within the Consortium in the very first part of the project allowed to define the benchmark solutions and to identify the requirements and targets for BLUESHIP to be competitive in the market, both from the technical and economical point of view.
The reference engine, vessel and fuel have been selected to identify the constraints, which the system will have to deal with. The target for NOx removal to deal with the upcoming regulatory framework has been defined. The needs and limits for the integration onboard of BLUESHIP SCR have been defined. The necessity of integration with the commercial dry De-SOx system provided by AKRETIA has been considered.
On the other hand, the requirements for the electrospinning equipment for the production of the nanofibres to be used as catalyst in BLUESHIP SCR have been defined.
As a conclusion, a complete set of requirements from the end user point of view, according to the industrial partners’ needs, have been identified and collected in a joint work.
The methodology applied for the collection of such requirements proved efficient and intuitive, and the immediateness of the requirements setup process, as it was suggested, made the involvement of the entire project partner easy, allowing for fruitful exchange of information and requests among the beneficiary SMEs and the RTD performers.
The outcome of the work is included in D1.1 and led to a shared vision of what the SCR reactor will have to perform, and of what it will have to be like, in order to be competitive and bring innovation in the addressed markets.
REGULATORY FRAMEWORK
The regulatory framework has been outlined, consisting in evaluation of the current EU and International regulations, especially focused on the MARPOL convention, that impose limits of emissions to the marine industry. This is a relevant point for the project, being this regulatory framework the main driver for the need of the BLUESHIP technology.
The most important regulation as relevance for the project is the MARPOL convention. The MARPOL agreement has been reached in the 1997, on an air-pollution annex to the International Marine Organization (IMO) MARPOL Convention – Annex VI. In particular Regulation 13 relates to “Nitrogen Oxide (NOx), emissions from diesel engines”.
This regulation 13 contains further a 3-Tier approach. To comply with Tier III, ships constructed on or after 1 January 2016 will have additional limitations when operating in an Emission Control Area. For the purpose of NOx emissions no Emission Control Areas (ECAs) have yet been designated, but it is expected that both the Baltic Sea and the North Sea will be designated well ahead of 1 January 2016. For Tier III ships operating in the NOx ECAs the allowable emissions of total weighted NOx depending on engine speed are:
• 3,4 g/kWh when n is less than 130 rpm
• 9,0 × n(-0,2) g/kWh when n is 130 or more but less than 2000 rpm
• 2,0 g/kWh when n is 2000 rpm or more
TECHNICAL BENCHMARK
The SCR technology has been analysed, its fields of traditional application evaluated and the main competitors listed. The design criteria and parameters have been identified and technical constraints evaluated.
The SCR for the marine application has been studied and the main parameters for the design of the reactor with respect with the catalyst are:
• Choice of catalyst as a function of the degree of conversion to be obtained
• Cell size of the catalyst in relation to the load losses and the efficiency of the catalyst
• Porosity and permeability of the catalyst
Regarding the process variables:
• Temperature of the flue gas line
• Operating pressure inside the reactor
• Composition of current flow into the reactor
• Degree of conversion desired
• Residence time in the reactor, and the inverse value defined as space velocity
The economic aspect was evaluated for standard SRC application as a reference for BLUESHIP. Fixed costs include initial capital and installation costs for the equipment. The major operational costs are those of the reducing agent (urea). The calculation tool recognizes that any fuel penalties which arise due to pressure drop across the SCR system are offset because a fuel optimized engine with an SCR system allows for a fuel efficiency benefit. Fuel savings can reduce the cost of SCR technology. Cost of a benchmark SCR were calculated for the for selected engine 6L27/38 for Tier II standard.
APPLICATION REQUIREMENTS AND EXTERNAL CONTRAINTS
The constraints for the application of BLUESHIP were defined, including:
• Marine fuel (heavy fuel Oil) HFO (up to 700 cSt/50° C, RMK700) MDO (DMB) _MGO (DMA, DMZ) according ISO8217-2010. Suggested fuel: Marine fuel ISO RMK 700 acc. to ISO 8217 classification.
• exhaust gas composition
• Reference vessel: new general cargo / 108TEU container vessel,
• Main Engine: 6L27/38 engine produced by MAN Diesel & Turbo (four stroke type, considered the most prevalent engine in the entire world).
• Arrangements for the exhaust gas cleaning system
• NOx content removal target: in ECAs regions for engine 6L27/38 acc. TIER III is 2.4 g/kWh,
• the pressure drop and velocity of the gas,
• The minimum temperature which for the selected engine, temperature of exhaust gas after turbocharger is 360°C.
The aim of the reactor design is also focussed at easy mounting procedure and easy monitoring of the chemical process efficiency and easy replacing of the wearied and or damaged part of the reactor, nonetheless that the SCR breakdown and maintenance cannot influence the continuous equipment and ME functioning.
NANOFIBRES AND ELECTROSPINNING PROCESS REQUIREMENTS
Different processes for production of fibres were analysed.
Manufacturers of electrospinning equipment have been listed and the existing commercial equipment evaluated for the needs of BLUESHIP fibres production.
Requirements related to the nanofibres and electrospinning process have been evaluated, consisting in:
• Shape and size of the fibres to be produced.
• Functionalization required
• Production capacity
• Economic requirements
TECHNICAL SPECIFICATIONS AND LAYOUT
This activity was mainly carried out by the RTD performers (LABOR, DTU and NEXT), who defined the technical specifications of the system and a preliminary layout of the final system.
In particular, we obtained the following results:
o List of the technical specifications for the 3 main groups, each coordinated by one RTD performer, dealing with: 1. Selective Catalytic Reduction process and reactor (LABOR), 2. Electrospinning process and apparatus for the production of nanofibres (NEXT), 3. Nanofibres used as catalyst (DTU). The deliverable provides a univocal identification of each technical and non-technical specifications, produced by the RTD performers on the basis of the functional requirements provided by the SMEs. It must be considered that the process of translation of the requirements into specifications has been realized through the following process.
o Preliminary layout of the reactor and of the technical choices to be used for the design and implementation of the BLUESHIP SCR reactor and plant. Concerning the choice of the solution for the deposition of the nanofibres for the production of the catalytic bed, the rolled filter support was identified as preferential option. The rolled filters, usually applied for diesel engine exhaust filters, consist of a planar element and a corrugated element bonded together one on top of the other. The resulting bi-layer is then tightly rolled to form a cylindrical filter with defined channels, which are related to the geometry of the corrugated element. This solution presents the advantage of allowing a continuous production directly coupled with the electrospinning deposition, it gives the possibility to modify the space of channels and then the permeability and active surface of catalyst. It can also be easily unfolded for regeneration and cleaning. The preliminary layout of the BLUESHIP SCR reactor is conceived as a cylindrical packed bed reactor, with several cylindrical catalytic bed modules put in series. The SCR reactor is included into a complete exhaust gas cleaning system (ECGS) plant layout. The arrangement identified for the BLUESHIP EGCS was defined for both low sulphur and high sulphur fuels usage.
A coherent set of specifications elicited by the Application Scenarios and the User Requirements has been overlapped and blended with the RTD Performers’ point of view, technology constraints, and stakeholders’ thoughts.
The work is concluded with the definition of the specifications for the BLUESHIP system (reactor and plant, nanofibres to be used for the catalyst and electrospinning apparatus for their production) and the definition of the preliminary technical choices for its implementation.
The specifications will then be used to guide the research and the design activities and to assess whether the system that will be developed in the project meets the established requirements.
Concerning the choice of the solution for the deposition of the nanofibres for the production of the catalytic bed to be used in the SCR, the rolled filter support was identified as preferential option. The rolled filters, usually applied for diesel engine exhaust filters, consist of a planar element and a corrugated element bonded together one on top of the other. The resulting bi-layer is then tightly rolled to form a cylindrical filter with defined channels, which are related to the geometry of the corrugated element. This solution presents the advantage of allowing a continuous production directly coupled with the electrospinning deposition, it gives the possibility to modify the space of channels depending on the way of packing the rolled filter (spacer between two layers), it can be easily unfolded for regeneration and cleaning. Several solutions for the choice of the geometry and for the material to be used for the support were identified and will be tested in lab in the next steps of the project.
The preliminary layout of the BLUESHIP SCR reactor is conceived as a cylindrical packed bed reactor, with several cylindrical catalytic bed modules put in series. The SCR reactor is included into a complete exhaust gas cleaning system (ECGS) plant layout. The arrangement identified for the BLUESHIP EGCS was defined for both low sulphur and high sulphur fuels usage.
This can be modelled as a plug flow reactor (PFR, sometimes called continuous tubular reactor, CTR, or piston flow reactors), which is commonly used to describe chemical reactions in continuous, flowing systems of cylindrical geometry.
The relevant parameters for the design of the reactor are:
• The length of each catalytic bed module (L) is fixed and the dimension is constrained by the electrospinning maximum deposition width.
• The diameter of the catalytic bed (D) and of the reactor will be defined according to the desired gas velocity inside the reactor.
• The number of modules (n) will be defined according to the required conversion efficiency of the reactor and the conversion per volume of catalytic bed.
The SCR reactor is included into a complete exhaust gas cleaning system (ECGS) plant layout. The arrangement identified for the BLUESHIP EGCS was defined for both low sulphur and high sulphur fuels usage. Two layouts were identified in this WP:
- Version A: in case a low sulphur fuel is used, it can be applied without a De-SOx and should substitute the silencer in the on board layout. This could be used for worldwide sailing vessels;
- Version C: in case a high sulphur fuel is used, a dry scrubber for De-SOx is used before entering the SCR. This could be used in vessels periodically navigating in the ECA areas and using high sulphur fuels.
In both cases, a safety bypass has to be applied to the SCR, to be used in case of maintenance and to bypass SCR when outside the ECAS regions. Summarizing, the preliminary layout of the BLUESHIP SCR reactor is conceived as a cylindrical packed bed reactor, with several cylindrical catalytic bed modules put in series.
--------- WP2 - SYNTHESIS AND FABRICATION OF CATALYST FIBRES (DTU) ---------
SYNTHESIS
SCR materials in the shape of nanofibres were synthesized by a sol-gel based method obtaining different morphologies with some differences in terms of catalytic activities. An important factor that to be considered in the electrospinning process was the up-scalability of the synthetic chemical route for the production of large quantities of fibres. This can influence the compositions as well as the morphologies obtained at the final product.
A basic chemical route was developed on the mixed use of Ti-alkoxides and salts/oxides of the catalysts. This method is feasible at the lab scale and it is very promising for the large scale.
Other crucial factors considered were stability of the starting solution, the presence of water in the process and a homogeneous incorporation, i.e. dissolution, of the catalysts (V and W) in the TiO2 anatase phase. These can also influence the morphology of the product. Small amount of water also leads to some changes in the morphology and presence of flaws in the material.
The following key-activities were carried out:
1. Optimization of the starting solution formulation as amount of acetic acid which is used both as catalyst of the chemical reaction and ligand agent. Acetic acid has a large influence on the stability of the starting solution, as well as, on the rheological features for the electrospinning process and thus on final morphology of the fibres.
2. Development of a synthetic strategy for a controlled use of deionized water in the starting solution. Water is added to the starting solution to prevent detrimental effect of high humidity in the ES deposition environment. In this context, water was added in a form that, together with the ligand agent, it could be used at the electrospinning for prolonged spinning time before flocculation due to polymerization of the alkoxides.
Acetic acid is used in the synthetic method as a fundamental component to stabilize the alkoxide precursors in the starting solution. In metal alkoxide chemistry (i.e. sol-gel), acetic acid is mainly used as acidic catalyst which activates the linear polymerization of the alkoxide via a low pH hydrolysis-condensation steps. On the other hand, acetic acid is also a chelating agent (i.e. a ligand) which can polarize the individual alkoxide molecules, inhibiting hydrolysis and condensation with formation of stable acetate-metal oxide complexes. However, an excess of acetic acid can also lead to complexation and precipitation of organometallic compounds. These complexes are more difficult to be hydrolyzed and they can even precipitate in the solution because they have poor solubility in alcohols.
The basic method includes the preparation of a starting solution based on titanium isopropoxide (TIP), vanadium acetate (V-AC) and tungsten ethoxide (W-ET) in Ethanol (99 %) in anhydrous conditions. In the basic formulation, no water content in the staring solution was added, to avoid uncontrolled hydrolysis and condensation of the starting alkoxides before the electrospinning process. Acidic catalytic conditions, by use of acetic acid, were used to promote linear polymerization of the alkoxides. For the lab scale, the starting solution preparation steps were:
- A small glass flask (25-50 ml), equipped with a rubber stopper, is connected to an Ar (or N2) pipeline. The inert gas is fluxed during the entire process to avoid presence of water within the reactor. The different (liquid) compounds are added using syringes as the rubber stopper can be easily punched;
- Acetic Acid is added in the Ac/Ti ratio: 2, 5, 10;
- The required amount of Titanium alkoxide is added. The solution is kept under magnetic stirring;
- The required amount of Tungsten alkoxide is added;
- The required amount of Vanadium oxyacetalacetone-ethanol solution is added. Such as solution must be prepared in advance.
- The required amount of PolyVinylPyrrolidone (PVP) ethanol solution is then added. Again, the PVP ethanol solution must be prepared in advance.
Optimized electrospinning conditions were:
• Constant Nozzle-target distance of 12 cm
• Applied voltage 36 KV
• 20-22 RH%
• 28-30 °C
• feeding rate 1ml/h
All the materials were calcined at the same conditions, i.e. 400 °C for 3 hours. The nominal composition of the fibre analyzed in the study was: V0.03W0.04Ti0.93O2-x. The use of water in the starting solution is a convenient option for the production of fibres in large scale, where a limited control of the electrospinning environment is expected or desirable.
This is due to the fact that metal alkoxides are chemicals which easily react with water undergoing to hydrolysis and condensation and uncontrolled polymerization on metal oxo-hydroxo compounds. The latter are irreversibly formed in solution and lead to gelification of the starting solution with increase viscosity.
CORE-SHELL FIBRE
With respect to the objective (to investigate two different morphologies: porous fibre and core-shell fibres, as requested by the SMEs the core-shell morphologies have been not investigated because not compatible with the needle-less equipment adopted by the consortium along the project. According to the contingency plan other composites made of nano-particles as starting materials have been investigated by a “hybrid sol-gel” chemical method (HSG).
The core-shell morphology was meant to obtain composite fibre morphology, where the core is made of a material with selected functionalities, e.g. catalytic substrate or mechanical strength, and the shell is the catalyst. This core-shell morphology can be made by co-axial needles electrospinning equipment, which, however, cannot be used for large scale production. Due to this limitation, an alternative morphology based on the use of nanometric powders on the catalysts was investigated. Conversely, to the core-shell, this can be produce starting from a single solution and it does not require co-axial needles equipment. Moreover, the results obtained indicate a feasible methodology to produce nanofibres with cheaper starting chemicals and easier control of the process.
Use of catalyst nanoparticle as constitutive precursor of the fibres has been carried out for the case on WO3. The results reported here are also applicable to the case of a direct incorporation of V2O5 or both WO3 and V2O5 nanoparticles. This method consists in the direct incorporation of some of the metal oxide constituents (e.g. WO3) as nanoparticles in the sol-gel starting solution. By this method, the metal oxide particles result embedded in the fibre precursor at the electrospinning. The fibres are then crystallized into the metal oxide matrix composites after the calcination step. The schematic representation of the process involves:
a. the nano particles are dispersed in starting solution;
b. the solution is spun into a PVP based fibre including the particles and the matrix precursor;
c. the fibre results in a composite of all the constituents after calcination.
REMARKS ON THE SYNTHETIC METHOD AND OPTIMIZED MORPHOLOGY
Activities in WP2 have demonstrated the feasibility of the proposed synthetic strategy for the formulation of co-doped TiO2 nanofibres for SCR application. Particularly:
1. The state-of-the-art synthetic procedure proposed for the pure TiO2 nano fibre has been extended in BLUESHIP to the complex formulation of co-dope V2O5-WO3 catalysts on TiO2 by calibrated use of alkoxides (i.e. W-ethoxide), metal salts (i.e. V-Acetate) and a ligand agent (Acetic Acid). This was done for the first time in this project for the synthesis on Electrospun nanofibres.
2. Use of ligand as chelating agent is a viable method to control the reactivity of the alkoxides reactivity during the process and it allows using a control amount of water, even in the starting solution. This fact creates a solid basis for the industrialization of the nanofibre synthetic process, especially for large scale production, where stability of the starting solution during processing and storage is a crucial factor.
3. Final morphology of the fibre is mainly affected by the quality of the starting solution and how the reactive surface area can be tuned by the process. In the BLUESHIP framework, the activities in WP2 have shown that an optimization of the process is possible and desirable to achieve the best SCR performance from the fibres.
Beside the different morphologies obtained, all the material tested presented fragility and their direct exposition to the mechanical stress and vibrations in the final BLUESHIP application would lead to a failure of the fibres. On the other hand, the core-shell design, where the mechanical strength is at the core of the fibre, cannot be considered as an option because this kind of fibres cannot be produced in large quantities in the consortium.
SCR CHARACTERIZATION
The evaluation of the catalytic performance (SCR) was carried out in conformity to the state of the art experimental setup.
The SCR lab-scale reactor consisted in quartz glass tube in a tubular furnace equipped at the outlet with sensors for NOx and CO, NO supply (bottles and MFC) and gas analyzers (mass spectrometry (MS) and chemi-luminescence detector (CLD)). The composition of the outlet gas is analysed with a quadrupole mass spectrometer (MS) Omnistar GSD 301 from Pfeiffer Vacuum and a chemiluminescence detector (CLD) Model 42i High Level from Thermo Scientific. The CLD can detect NO, NO2 and NOx, all nitrogen oxides were registered as NOx. The MS was used measure the concentration of NO, N2, CO2 and O2, with the limitations reported in D2.2. Freestanding nanofibres samples were extensively characterized in a lab-scale reactor able to control critical parameters such as temperature, ammonia concentration, presence of water etc. This enables to estimate and compare the performance of the materials produced in the different conditions. The key-parameters in the catalytic character of the fibres are:
1) the composition of the catalyst,
2) the phase at the TiO2 substrate, and
3) the fibre morphology (i.e. the porosity and the specific surface area).
The TiO2-V2O5-WO3 with high catalyst contents (e.g. V2O5-WO3 above 1.5 % in weight) can easily give full NOx conversion (i.e. 100 % conversion of NOx into N2), especially at the high temperatures above 300 °C. In this work, the amount of samples used at each test is only 20 mg for a flow of 6 L/h. Such small amount of catalyst leads to conversion degree that rarely exceeds 90% even at the high temperatures (e.g. 400 °C). This choice allows estimating the effect of the slight changes in conversion degree due to variation of the microstructural features of the nanofibres. The lab-scale SCR characterization device is describe in detail in D2.2.
FIBRE – NETWORK PATTERNING
Alignment and patterning of the fibre can be an important factor to vary the catalytic activity and the dynamic of the fluids in at the SCR reactor. Oriented or random fibre result in different reaction kinetics as well as in a different distribution of the fluids (both reactants and reagents) at the reactor. However, while random fibres are easily produced, oriented fibres usually required high rotational speed at the fibre collector or special pattering at the collector. The high rotational speed at the collector is usually used in needle-based ES equipment and thus is difficult to up-scale. Conversely, using a patterned substrate can lead to a preferential orientation of the fibres during the electrospinning. However, in this case the alignment is determined by the substrate geometry and by the configuration of the electrostatic field on it during the electrospinning process.
The planned work was originally devoted to design simple patterned network realized by the use of rotating drum collector which allows wrapping the spun fibres with a selected orientation by rotating the collector. The up-scalability of the fibre production is found to be a critical point in the technological transfer of the produced fibres to the industrial level, as none of the commercially available large scale electrospinning equipment allows high speed motion at the collector such to allow fibres orientations. The deviations in the R&D activities have been carried out on the track of the technical risks assessment and mitigation and have been discussed and approved by all the partners at the steering meetings.
Orientation by drum collector rotation
Randomly oriented fibres are easily formed at any rotational speed below 50 rpm at the large collector (8 cm), i.e. relative speed between the nozzle and the collector below ca. 20 cm/sec. On the other hand, a few examples of microstructures obtained tuning such operation conditions are reported.
The use of very fast rotational speed was also tested as high as 2000 rpm on collector of 0.3 cm was tested to check the limits of the technique (relative speed ca. 30 cm/s). SEM observation showed, however, that the material results compact and several preferential orientations in the different parts of the sample. The materials resulted locally aligned and very defective with several beads, broken fibres, agglomerated particles and entanglements. The conclusion about the use of high rotational speed for the fibre alignment is that rotating collector can impose a preferential orientation to the fibres when the relative speed is above 100 cm/s. However, the materials also result randomly oriented and very fast rotations at the small collector can lead to undesired lateral motions such as vibrations and wobbling, leading to defects, heterogeneous fibres organization and lack of long range orientation.
Orientation by patterning
Since the use of fast rotational relative motion between nozzles and collector is difficult or even unfeasible in the large scale ES equipment, an alternative strategy was elaborated to obtain oriented fibres. Patterned counter-electrodes are known to impose a preferential orientation to the deposited fibres. This is due to the fact that the electrostatic filed is preferentially distributed on electronic conductors and not on insulating materials. Therefore, during the electrospinning process the spun solution targets the metal collector and not the insulating material. The result is that the fibres are deposited along the metal collector, reproducing its geometry, as well as across the insulating parts creating ordered depositions. The meshes used were mainly of two kinds:
1. Expanded mesh: this is an mesh made by shearing a metal foils in a press, so that the metal stretches, leaving diamond-shaped voids surrounded by interlinked bars of the metal
2. Wired mesh: this is a conventional mesh done by waving metallic wires defining squared apertures.
As result of the geometrical shaping, the expanded mesh presented fibres with a dominant orientation along the longer side of the apertures. On the other hand for the wire mesh, the fibres crossed along the two perpendicular directions of the wires.
SCR performance
The SCR tests were performed in a comparative fashion on self-standing fibres arranged randomly and with preferential alignment. Low amount of catalyst 20 mg at the steady flow of 6 L/h was tested in dry conditions to avoid uncertainties in the measure (see D2.2. for details). Due to the geometry of the SCR reactor used for the lab scale analysis, only fibres laying perpendicular to the flow could be tested. SCR characterization of the fibres with preferential orientation parallel to the flow direction is in fact only possible where the fibres were supported on a substrate. Moreover, due to the reduced height of the hot zone in the reactor, the self-standing fibres layers could not be handled in the quartz tube in a perpendicular position without crashing them. On the other hand, the lab-scale reactor geometry did not allow an analysis of the supported configurations and fibres with alignment parallel to the gas flow was not feasible at the lab scale.
The data shows that both randomly oriented fibres and aligned fibres by fast rotational speed at the drum collector have SCR performance comparable to the reference and largely above the 80% at an operative temperature above 300 °C. These results confirm the ones previously reported in D2.1 and D2.2 and consolidate the principle that the nanofibres are comparable with the wash-coating catalytic layer in the state of the art SCR. The other hand, the sample deposited on the metallic mesh with typical NOx conversion rates above 40%.
This kind of sample has microstructural features with well-packed aligned fibres and large apertures which replicate the shape of the supporting mesh. Since composition and packing of the fibres is the same for all the samples, the presence of the aperture was pointed as possible cause of lack of conversion in the patterned sample. This is also possible considering that large aperture are low resistance paths for the gas through the sample which decrease the actual residence time in the reactor. This factor is also plausible considering that, at the lab-scale SCR, the reactive bed sample has a thickness (hundreds of microns of the deposited fibres) that is very low compared both to the area of the section of the reactor (12 mm) and the actual height of the reactive zone (2 mm). On the other hand, such feature may be beneficial in a real application, where the pressure drop through the SCR has to be minimized.
SCR LAB SCALE REACTOR ASSEMBLY
A small scale reactor made of TiO2-V2O5-WO3 nanofibres deposited on metallic mesh was assembled with the purpose of testing oriented and random fibres at the catalytic level in a reactor-like configuration. A previously mentioned, a small lab-scale reactor has been implemented with the purpose of testing the SCR performance of fibres with different orientation but also to support the other activities in the project dealing with supporting the fibre and designing the final reactor prototype. As a result, the designed reactor was not suitable for conversion and several issues were observed both at the reactor SCR test and at the reactor design levels, which are herein presented.
Concerning the test, the use of a large a canning in the quartz tube was not suitable. At least two major issues were identified along the several tests carried out on the reactors. Firstly, the gap between the quartz wall and the aluminium tube was difficult to seal and the different thermal expansion during the test was opening new possible leaks path at the gas flow. Secondly, the temperature in the distribution in the reactor was not homogeneous due the small hot zone of the tubular furnace in use at the lab-scale SCR setup.
Concerning the reactor design, two major issues:
1. Shrinkage of the fibres on the deposited substrate, as anticipated in D2.1 the shrinkage process from the deposition to the calcination steps is very large (around 60 % in volume depending on the composition of the starting solution).
2. Poor adherence of the fibres on the mesh. Thick layers above 10 µm of fibres deposited on the mesh tend to delaminate. Since fibres have poor mechanical resistance and are very lights, unsupported fibre can easily leave reactors flying with under the stream of gases. On the other hand, thin depositions below 10 µm adhered to the substrate. However the amount of fibres, and thus of the catalytic layer on the mesh, is very low and the residence time probably too low to efficiently convert NOx.
DEPOSITION ON METALLIC MESH SUPPORT
Due to the poor mechanical resistance of the ceramic nanofibres, a substrate to be used as mechanical support was selected by the consortium. The choice was especially oriented toward stainless steel mesh because of the low cost and large availability. The critical factors in the use of the metallic support are:
1. Thickness and coverage of the deposition on the substrate
2. Adhesion of the fibres on the support
These two factors can also result correlated by the fact that the layer deposition influence the critical stress that can lead to delamination. Other factors which lead to delamination are related to the corrosion of the support, such as:
- Thickness and coverage of the deposited layer;
- Adherence, corrosion and layer delamination;
- Self-standing material.
Despite the high performance of the nanofibres developed in WP2, a support is needed to operate the SCR catalysts. The deposition of the fibres is however complicated by the large shrinkage of the as synthesized material during the calcination. This is due to the large quantities of solvent, co-solvent and additives necessary to stabilize and spun the solution. A significant reduction of the shrinkage is thus difficult to achieve with the chemical methods established in the project. On the other hand, the calcination of the deposited fibres directly on the support can easily lead to delamination and loss of covered area, impairing the actual activity of the SCR reaction. Experimental evidenced indicate that lack of deposited fibres at the metallic meshes selected for the project can create preferential open path at the SCR reactor with very limited SCR activity. The chemical composition of the substrate and corrosive effects has to be considered to ensure a proper adhesion of the fibres on the substrate.
SELF-STANDING FIBRES
As discussed, the mechanical strength of the fibres is low and for these reason these have been used on different substrates. However, the mechanical fragility of the fibre relates to the critical strain of the material. For 1D material such nanofibres, bending can easily occur unless the material is not constrained in a fixed position. Fixing the fibre on a mechanical support can indeed avoid the failure. Another solution that can be thus considered is thick layers on several mm or cm. When the thickness of the deposition becomes large the fibres become self-sustaining and the critical strain can be avoided.
GENERAL CONCLUSIONS IN WP2
As general conclusion of the R&D activities in WP2, we have shown that TiO2-V-W nanofibres by electrospinning method are suitable for SCR applications. The material shows suitable conversion and catalytic properties that are equal or superior to the commercial sample. This is with the advantage that the materials is directly formed in the nanofibrous morphology, which is in principle the best morphology for gas treatment because it present only open and interconnected porosity.
However, although the high potential, the integration of the material in a reactor is still open due to the limitation in the processing methodology and mechanical performance of the thin deposition.
The conclusive remarks are:
1. A robust method for the synthesis of SCR Ti-V-W nanofibres has been developed and optimized in terms of starting precursors and process parameters.
2. Process parameter can influence the final morphology and affect the SCR properties.
3. Stability of the starting solution can be optimized and tuned depending on the electrospinning method, equipment in use and storage conditions.
4. A fine characterization of the chemical, structural and microstructural features of the BLUESHIP nanofibres indicate that, since the fibre present high NOx conversion, the composition of the catalyst can be tuned, e.g. by reducing the amount of W. This is the most costly component among the precursors used in the BLUESHIP methodology.
5. Large shrinkage of the fibre at the calcination step represents a critical limitation for the fabrication of the reactor. The contraction of the deposited fibres is mostly associated to the chemistry of the starting solution, which present limited degrees of changes. Large shrinkage above 60 vol. % occurs also on the deposited material and planar constrain to avoid delamination is effective only for thin deposition below 1-2 microns.
Self-standing thick mads in mm range present enhanced mechanical properties and it can represent a solution for the use of the material in the reactor. However, further development for the design and integration in the reactor would be needed.
--------- WP3 - MODELLING AND DESIGN OF ELECTROSPUN SRC (LABOR) ---------
The work conducted in this WP was related to simulate the fluid-dynamic behaviour and of the kinetics of the reaction inside the reactor, by means of computer-aided design techniques and models, identify the layout, dimensioning and design of the SCR for the target application specified in WP1. To achieve the optimization of the reactor design the following steps were followed:
- fluid-dynamic tests and a study of characterization of cell geometry were conducted on different rolled filters, selected in T3.1 as solution to implement the catalytic support for the SCR: a theoretical function was obtained to calculate the geometrical characteristics of the cells by fitting experimental measures, a method for calculation of the equivalent diameter was derived; a method for the calculation of the permeability of the filters from the geometrical characteristics was obtained through parametric calculation;
- the catalytic filters and the SCR were dimensioned to meet the requirements specified for the target application specified in WP1;
- simulations were carried out to verify the pressure drop, gas velocity and the yield of reaction inside the dimensioned reactor, by means of computer-aided design techniques.
MODELLING OF THE FLUID-DYNAMICS AND THE CHEMICAL KINETICS
The study of the solutions for the implementation of catalytic modules to be used in SCR reactor led to the selection of rolled filters as support for the deposition of the Electrospun fibres. The catalytic support selected for BLUESHIP SCR modules has a cylindrical geometry and is composed of a series of cells, in which the gas flows. The Electrospun catalyst is deposed as a thin layer onto the surface of the support, being in contact with the flow in the cells. These modules, known in commercial applications as rolled filters, have considerable advantages due to their high specific surface area and the possibility of deposition of the catalyst through a continuous deposition, easily scalable for industrial application. In addition, the pressure drop in each module can be controlled by varying the density of cells, usually identified by the parameter cells per square inch (CPSI) in commercial products.
Under this task, Labor has developed three models of the preliminary dimensioning and verification of fluid-dynamics behaviour of the BLUESHIP SCR:
• A simplified model for the preliminary sizing of the reactor based on rolled filter modules configuration, implemented using spreadsheets on MS excel. This model allows to calculate, for specified operating conditions and given space velocity (or residence time) which depend on the required degree of conversion: the volume of the reactor, then the volume of each single module and the optimal CPSI (Cell per square inch) of the rolled filter used as support for the catalyst, to have a comparable surface area with presently applied honeycomb catalyst structure.
• A geometrical optimization model implemented in MS Excel, which allows to calculate, for the given configuration and given permeability of the filter, the pressure drop in the reactor, and optimize the aspect ratio of the duct according to the value of pressure drops permissible. In this optimization phase, the variables to optimize are: the angle of the divergent, the diameter of the duct and the length of the modules.
• A CFD model implemented in OpenFOAM environment, used to simulate the fluid-dynamic behavior of the gas inside the reactor and the chemical conversion. The set of solutions defined with the simplified models will be simulated with the CFD model to validate the behavior at a more detailed scale.
To study the influence of the cell density of rolled filter on the permeability of the filters, which represents the ability to be traversed by the fluid and is a key factor in the CFD modelling, a test bench was implemented in this task for the experimental evaluation of the pressure drop on rolled filters. Results of preliminary tests on rolled filters were compared with a theoretical evaluation of the pressure drop for different cell density. In the next task further tests will be carried to correlate the experimental and the theoretical evaluations.
As a reference, first dimensioning of the SCR reactor was carried out. The volume of SCR is constrained by the residence time of the flue gas in the reactor, in order to have the desired conversion of NOx (τ = 0.18 s). This, for the volume to be treated means a reactor volume of 1.5 m3, which was dimensioned with 100 cm diameter and 150 cm height, consisting of 3 modules each with height 50 cm. When adding the divergent, the stagnation areas and the convergent, a total length of about 4.5 m was achieved.
The preliminary design procedure applied through the models implemented follow the steps below:
• Input data (kinetic data, volumetric flow ratio, reactor type, catalyst support solution, operating conditions, conversion degree);
• Simplified model for the preliminary sizing (set of optimal configuration – space velocity, volume of reactor, CPSI of the catalytic support, permeability of the support etc.);
• Simplified model for geometrical optimization and pressure drop calculation (angle of the divergent, diameter of the duct and the length of the modules);
• CFD simulation (verification of the pressure drop and chemical conversion of the reactor).
For what concerns the study of the fluid-dynamic behavior, needed for the evaluation of the pressure drop in the SCR system, first a theoretical characterization of the total pressure drop in the SCR system was carried out, in order to highlight the parameters that affect it. To calculate the load losses starting from the previously reported theoretical study, a simplified model developed in MS Excel spreadsheet was used as first approximation. The effect of variation of geometric parameters (divergent and convergent angles and reactor length) on pressure drop was evaluated.
PARAMETRIC STUDY AND DESIGN OF THE SCR UNIT
The task concerns the use of the simulation model, developed in the previous Task 3.1 for performing a geometrical optimization of the SCR, in order to find the most suitable solution among two/three different options as a trade-off between simplicity, compactness and resistance time for the efficiency of the catalytic reaction in presence of catalyst.
To achieve optimization of the reactor design the following steps were followed in this task:
• From preliminary tests conducted on the rolled filters selected in D3.1 a study of characterization of cell geometry was conducted;
• A theoretical function was obtained to calculate the geometrical characteristics of the cells by fitting experimental measures, and a method for calculation of the equivalent diameter was derived;
• The match between experimental and theoretical data for the pressure drop was obtained through parametric calculation, from the geometrical characteristics of the cells according to the flow;
The target of the project is to double the surface area of the filter with equal volume. Once defined the geometry and the number of cells, the filter is dimensioned to achieve the requirements.
The results implemented by LABOR in this task are the following:
simulation models supporting the dimensioning of the reactor and the concept design
definition of reactor and plant design layout with the required control system and dimensioning of the final reactor adopting the rolled filter support as catalytic modules
Models implemented for the dimensioning and verification of fluid-dynamic and kinetic behavior of the BLUESHIP SCR reactor are the following:
1. Model for the geometric characterization of the cells and the calculation of the available surface for rolled filters depending of the number of cell density:
a. Characterization of the geometry of the cells to the filters 300, 600, 900 CPSI;
b. Extrapolation using the calculation model of the passage section and wetted perimeter;
c. Measurements of load loss on the filters for experimental fitting;
d. Fitting of experimental data per cell sizing;
e. Iterative calculation for the optimization of the equivalent diameter.
2. A CFD model implemented in OpenFOAM environment, used to simulate the fluid-dynamic behaviour of the gas inside the reactor and the chemical conversion of the SCR reaction.
DIMENSIONING OF THE BLUESHIP SCR UNIT
The dimensioning of the BLUESHIP reactor for the application identified and specified in D1.2 was carried out starting from the main constraints: conversion, load losses permissible in the reactor, activation temperature of the catalyst, space and weight constraints.
The conversion depends on the chemistry of the reaction and is closely linked to the amount of catalyst per unit volume and the surface area of the support.
The pressure losses depend instead on the input flow rate and the size of the cells of the support. To dimension the reactor we must therefore consider several variables and move in phase space for proper configuration.
To calculate the space velocity, the kinetic data obtained at DTU while making preliminary tests on catalytic activity of material were used as starting point to determine the best operating conditions for achieving optimum efficiency.
Tests at DTU were conducted on 20 mg in a glass reactor of 0.3 cm3. On the base of these conditions, the space velocity was calculated. Once determined the space velocity at lab scale, we calculated the volume of the BLUESHIP SCR reactor for treating the mass flow rate specified in D1.2 using the preliminary model for dimensioning implemented in MS Excel, here reported. The assumed and target values are therefore:
• Volumetric flow rate: 26.658 m3/h
• Rolled filter cell radius = 2 mm
The following assumptions are also made:
• Active surface of the catalyst is equal to the surface of the support onto which it is deposed (no higher surface due to the high specific surface of fibres is considered). Of course the use of fibres will give an active surface factor well above 1 (first estimation considered was 10 m2/m2), increasing the catalytic active surface with the same support surface. This will allow reduction of the cell density with the same reactor volume or improve the conversion with the same volume (or balance of the two).
• The deposition of the catalyst is realized on both faces of the corrugated surface of the rolled filter.
To carry out the geometric dimensioning of the reactor, we set variables specified by the project in D1.2 and we have obtained the equivalent diameter required to comply with the project specifications. By setting the maximum value of allowable pressure loss and the geometric dimensions of the reactor obtained from the preliminary dimensioning reported in D3.1 using the iterative spreadsheet we obtained the equivalent diameter and below wetted perimeter and surface extension of the reactor.
The iterative calculation yielded the following results:
• Hydraulic diameter 4mm
• Reactor diameter 1500 mm
• Reactor module length 500 mm
• Number of modules 3
• Reynolds number 700
• Reactor volume 2,64 m3
• Space velocity 10075 1/h
Once we know the hydraulic diameter we can calculate the cross section of each cell, then the number of cells and the corresponding cell density.
ANALYSIS OF KINETIC BEHAVIOUR OF ES CATALYST
In the BLUESHIP reactor the reaction takes place between two reagents: NOx and NH3 activated by a catalyst. The reagents are in gaseous phase while the solid catalyst is deposited in the form of nanofibres on a support corrugated as described above. The reaction is then a reaction catalysed heterogeneous, in particular the reduction reaction of NOx follows the Langmuir model. At the operating temperature of about 350 ° C the model of adsorption is described by Eley-Rideal. The reaction takes place on the catalyst surface as described by the model.
Reactions on surfaces are reactions in which at least one of the steps of the reaction mechanism is the adsorption of one or more reactants. The mechanisms for these reactions, and the rate equations are of extreme importance for heterogeneous catalysis. The necessary first step in a heterogeneous catalytic reaction involves activation of a reactant molecule by adsorption onto a catalyst surface. The activation step implies that a fairly strong chemical bond is formed with the catalyst surface.
This mode of adsorption is called chemisorption, and it is characterized by an enthalpy change typically greater than 80 kJ mol - J and sometimes greater than 400 kJ mol- J. Since a chemical bond is formed with the catalyst surface, chemisorption is specific in nature, meaning only certain adsorbate-adsorbent combinations are possible. Chemisorption implies that only a single layer, or monolayer, of adsorbed molecules is possible since every adsorbed atom or molecule forms a strong bond with the surface. Once the available surface sites are occupied, no additional molecules can be chemisorbed. In task T3.2 we could calculate the kinetic constant by numerical integration starting from DTU data.
CFD SIMULATIONS RESULTS
According to the theoretical analysis developed in the previous section, we have developed a numerical simulation model in the OpenFOAM environment. The analysis has been conducted on a reactor configuration sketched in D3.2 characterized by:
• a divergent inlet section, characterized by an inlet angle θd = 20°;
• a cylindrical section with constant diameter, containing three SCR modules;
• a convergent outlet section, characterized by an angle of θc= 36,5°.
By simulating different configurations w obtained the following:
• Configuration 1: R1=0.267 m, R2 = 0.75 m, Ld = 1.34 m, θd ≈ 20°, Lc = 0.66 m, , θc ≈ 36.5°, Lm = 0.5 m, LSCR = 2.1 m, Ltot = 4.1 m; S/V=200 1/m;
• Configuration 2: R1=0.267 m, R2 = 0.75 m, Ld = 1.34 m, θd ≈ 20°, Lc = 0.66 m, , θc ≈ 36.5°, Lm = 0.5 m, LSCR = 2.1 m, Ltot = 4.1 m; S/V=400 1/m;
• Configuration 3: R1=0.267 m, R2 = 0.75 m, Ld = 1.34 m, θd ≈ 20°, Lc = 0.66 m, ,θc ≈ 36.5°, Lm = 0.5 m, LSCR = 2.1 m, Ltot = 4.1 m; S/V=600 1/m.
It should be noted that:
1. Reference operating conditions (gases composition, mass flow and temperature) are consistent with the baseline values fixed in previous reports;
2. The main geometrical features of the complete SCR section (R1, R2, θd, θc) have been determined according to the previously performed computations, that aimed at reaching an optimum between pressure losses and the system compactness;
3. The configurations differs in surface-to-volume ratios of the catalytic porous medium (porosity is set to 85% for all cases).
The variables used in the simulation are the following:
• Conversion of NOx
• Gas velocity
• pressure drop in the SCR reactor
The geometrical configuration of the reactor is the same for all configurations and has been analysed the behaviour based on the amount of deposited catalyst (using the S / V ratio) S/V ratio is the ratio between specific surface (defined as surface in contact with gas) and volume of filter.
Results of the simulations ran in this task can be commented as follows:
To achieve very high conversion degrees, increasing the S/V parameter appears to be a more efficient choice compared to the adoption of longer catalytic modules; this is especially true if the S/V increase is obtained with little modification of the overall porous media characteristics (i.e. with small alterations of the viscous and inertial pressure losses);
It should be underlined that the predicted conversion values rely on some simplifying assumptions, such as no ammonia slip and coverage effects, no fouling and a catalyst medium operating at state-of-the art NO conversion performance; this means that, to achieve an overall conversion above 60% for a 1 m long catalytic section, the S/V ratio should be most likely higher than 400; the usage of longer conversion modules is not recommended, unless the viscous and inertial resistance coefficients of the overall structure (support + catalytic medium) can be further reduced compared to the above calculated values.
According to these results, we can notice that 600 S / V ratio is the best case, the required conversion is reached in the middle of the reactor, and then is the case with better performance.
The conclusions of the work carried out in Task 3.2 which was the only ongoing activity under WP3 in the reference period, can be summarized to be:
1. The selected support are rolled filters with a density of cell equal 25 to cells per square inch (CPSI) with an hydraulic diameter of 4 mm, the deposited fibres have a surface area of 40 m2/g and the amount of deposited catalyst is equal to 1g /m2. This means that thanks to the large specific surface of the fibres it is possible to reduce the volume and size of the modules as required in D1.2.
2. The fibres show catalytic activity equal to the reference catalyst and ensure the achievement of the conversion target required.
3. The sizing according to the procedure described product has the following results:
a. Reactor diameter d = 1.5 m height of a single module h = 0.5 m number of modules needed for the required flow rate N = 3 cell density 25 CPSI, thickness of the foil 0,1 mm.
b. Volume of the catalytic modules V =2,64 m3.
c. Specific surface of 961 m2/m3 for each module.
d. Total length of SCR reactor is 4,1 m with divergent angle equal to 20° and length 1,34 m.
e. The convergent angle is equal to 36,5° and the length is 0,66 m.
4. The weight of the dimensioning SCR is 1077 kg for 25 CPSI cell density. The weight of the reference module is of 2200 kg, the weight reduction compared to the state of the art is 50%.
5. The speed inside the modules is less than 10 m/s and the flow is laminar, this ensures the residence time required for the conversion.
6. The catalytic model selected to simulate a kinetic reaction is Eley – Rideal mechanism. Only one reactant is adsorbed on the surface and the kinetic equation is the first order respect NOx.
7. The CFD simulation shows how the conversion varies depending on the particular surface/volume ratio the best performance is obtained for a S/V ratio of 600 1/m. In addition it can be seen how the pressure drop is lower than the required and the temperature is in the range allowable for the reaction.
8. The control system strategy is explained and the process and the instrumentation scheme is show with the logical of control.
--------- WP4 - IMPLEMENTATION OF THE ES-SCR UNIT (NTT) ---------
The objective of WP4 was to define and optimize at pilot scale the production of ceramic nanofibres in order to ensure that the process could be easily transferred at Industrial scale with minor modifications. The most proper device to be used for process scale-up was defined according to technical features of different options that are available within the consortium. The produced nanofibres have been characterized at a preliminary unit was realized. The process and parameter conditions for the processing of the precursors mixture have been optimised and the lasting performance of the solution has been characterised in order to verify the replicability of lab scale production at large scale. The optimal support for the catalytic nanofibre deposition has been defined and the protocol for the production of the photocatalytic filters has been set up.
MAIN RESULTS ACHIEVED IN THE WP
A straightforward way to increase the electrospinning throughput is to use multi-jet spinnerets: the fibre productivity can be simply increased by increasing the jet number. However, multi-jet electrospinning has shown some drawbacks: 1) strong repulsion/interferences among the jets and clogging of the needles. Thus, needless electrospinning represents the most suitable method for manufacturing nanofibres since conical spikes on the surface of a solution layer upon a cylindrical electrode can be generated reducing problem related with cleaning and jets interferences.
Accordingly, production of Titanium Dioxide nanofibres has been scaled-up at NTT by means of needless ELMARCO Electrospinning equipment (NanospiderTM Production Line NS LAB200).
FABRICATION OF FIBRES AND CHARACTERISATION BY LARGE SCALE ELECTROSPINNING APPARATUS
The production of large-scale nanofibres by using Needleless ES apparatus available at NTT has been optimised for the production of catalytic ceramic nanofibres by investigating the effect of single functional components in the process conditions (kind of electrodes – both spinning and collector electrode; Voltage; Distance between the electrodes), under the Task 4.2.
The objective of the Task 4.1 was the identification of the optimal process conditions for the production of ceramic nanofibres with a composition set-up within WP2 at lab-scale by using needleless apparatus. This apparatus has been selected as the most promising and reliable for the production of nanofibrous material at industrial scale.
Process (parameters associated with the design, geometry and operation of the electrospinning apparatus), system (properties associated with the solution used as feedstock) and environmental (atmospheric and other local processing conditions) parameters have been optimized and defined since they are affecting the throughput and the morphology of the resulting nanofibres.
Morphological analyses carried out at optimised conditions show that average diameter is 247 ± 89 nm even if there are some defects (mainly beads) in the nanoweb. Furthermore the addition of water is confirming that the stability of the solution is sufficient to properly run the production in continuous for 2 h.
After 1.5 h – 2.0 h a significant increase of the defect is recorded (from 7-10% of the covered area at the beginning of the production up to 48 – 54% after 2 h) induced by the instability of the Taylor cone. Since the stretching of the nanofibre is induced by the polymer an additional trial with large amount of PVP (1.2 mol/mol) has been carried out to verify if there is a benefit in the morphology of the hybrid nanomaterial.
SEM measurements do not show any benefit in the morphology so it has been decided to keep the recipe reported in Deliverable 4.2 - Characterization of fibres produced with large scale ES equipment - as the most suitable for the large scale production of catalytic nanofibres.
The deposition of catalytic nanofibres onto the surface of metallic supports (AISI stainless steel nets and AISI stainless steel corrugated sheets) has been then carried out in order to characterise ES efficiency for the production of catalytic filter. The optimisation process for the deposition of the nanofibres onto metallic nest have been performed on AISI Stainless steel nets, as well as, AISI Stainless steel sheet, for further details please refer to the Deliverable 4.2. As a result, the scale up for the production of catalytic ceramic nanofibres has been optimised and productivity up to 3.5 g/m2 has been achieved. The geometry and morphology of the supports is not affecting the throughput and morphology of the fibres. The corrugated sheets have been selected as the most suitable support for the production of catalytic filter.
IMPLEMENTATION OF THE ES-SCR UNIT
The prototype of pilot scale BLUESHIP SCR was designed and implemented. The reactor was implemented with specifically realized catalytic filters realized with nanofibers deposed over corrugated /plain metal sheets representing the selected rolled filter configuration. The prototype was equipped with
The pilot prototype was equipped with a specifically designed and realized test bench for data acquisition and control system. Pilot prototype was installed at the testing facilities identified to verify the functionality of the solution for NOx abatement on a automotive diesel engine.
The BLUESHIP ES-SCR pilot scale reactor for ‘proof of concept’ of the layout of reactor defined during the project, was designed, implemented and integrated by LABOR in a test bench for the treatment of exhaust gases of an automotive diesel engine (FIAT Doblò van 1.9 Multijet) at the facilities of the department of the Mechanical Engineering of University of Rome Sapienza, Italy.
The design of the BLUESHIP prototype was carried out taking into account the objectives indicated in the contract, to realize a pilot scale application with size of about 50x50x25 cm and a test bench for its validation, and starting from the concept layout of the BLUESHIP SCR defined in WP3. The catalytic elements provided by NEXT, were defined to resemble the rolled filter concept identified as support solution for the deposition of the electrospun catalytic nanofibers. Each module is in fact constituted by a cube (side = 5 cm) where the support, made of AISI 316, is constituted of layers of corrugated sheets alternated to plain sheets, on which the catalytic fibers were deposited by NEXT on both sides before calcination .
The catalytic modules (5) were assembled and inserted into a specifically designed reactor, which was mounted in by-pass line respect the exhaust gases main line. By means of a manual proportional valve the exhaust gases are conveyed towards the reactor and treated. The NOx value is registered before and after the catalytic reactor to prove its efficacy.
The prototype is equipped with an auxiliary urea line mixed with the exhaust gases before entering the reactor, whose flow is controlled remotely in order to guarantee the proper urea-NOx stoichiometric ratio, and sensor (flow, temperature) to follow the reaction parameters.
A dedicated software in LabVIEW environment was developed to control and manage the test both in manual and automatic mode. The overall layout of the experimental setup built up for the project is shown in the conclusion. The system has been assembled at LABOR’s premises in Rome and then installed at the test bench facilities. Pictures of all the components and of the final assembly installed at the test bench facilities are provided in the document.
The design of the BLUESHIP prototype was carried out taking into account the objectives indicated in the contract, to realize a pilot scale application with size of about 50x50x25 cm and a test bench for its validation, and starting from the concept layout of the BLUESHIP SCR defined in WP3.
Starting from the process and instrumentation scheme, the prototype was assembled. This is constituted by a reactor mounted on a by-pass line of the main exhaust gases line. Before reaching the reactor, the exhaust gas is mixed with urea according the stoichiometric ratio between CH4N2O and the amount of NOx produced by the engine. The manual partition valve allows the operator to regulates the by-pass flow according the flow meter capacity while the temperature is monitored, and if necessary controlled by means of heaters, in order to maintain its value around 350-400°C to favorite the catalytic reaction. After being treated the gases are discharged.
The SCR reactor is constituted by a 5x5cm stainless steel hollow parallelepiped housing, inserted and welded into a stainless steel cylinder. The empty room between the parallelepiped and the cylinder is used to adapt and insert 4 heating elements, series Rotfil-Ultramax, dimensions 12,5 X 300mm, capacity 500W each.
The heaters are thought to compensate the heat dissipation along the piping. The temperature at which the reaction occurs is optimal around 400°C, therefore if the piping between the engine and the reactor is too long there is the possibility that the exhaust gases decrease their temperature too much under such value.
• The catalytic element
The catalytic element was provided by NEXT, to resemble the rolled filter concept, identified as solution for the deposition of the nanofibers for BLUESHIP SCR. It is constituted by a cube (side = 5 cm) where the support, made of AISI 316, is constituted layers of corrugated sheets alternated to plain sheets. Before assembling the cube, the catalytic fibers were deposited on both the corrugated and the flat sheets.
• Urea injection system
In order to inject UREA into the exhaust gases line a flange system have been welded where a 90° bended tube presents on the head inside the flanged tube a thread to screw a 0.30 mm N-oxide stainless steel nozzle with Stainless impeller plate with anti-drip filter. The other extremity of the tube is connected to a volumetric pump, brand Prominent, type beta 4, working pressure 16bar, flow rate 4 L/h.
• Partition Valve and piping optimization
The valve is a butterfly type valve where the handle was modified and a 90° goniometer was integrated to regulate the opening of the valve from 0°, totally close, to 90°, totally open. In order to integrate the parts and elements of the prototype, it was necessary to optimize the piping, according also the room available at the installation site where the prototype is mounted.
• The software
In the following the description of the dedicated software interface developed to interact between the end user and the prototype is provided. The software, developed in LabVIEW environment, provides all the function to control and manage the test bench prototype. The software allows the operator to perform the following actions:
- Set the parameters of process (RPM: engine regime, TI – ENG: engine temperature, FI – ENG: exhaust gases temperature, Deg [90]: V01 manual regulation degrees, Ppm in: NOx in parts per million without catalysis, Ppm out: NOx in parts per million after catalysis, Set point: temperature of the reaction, Stoichiometric ratio: explicit for the UREA flow),
- Start the measure in manual mode or automatic mode,
- Log the data of process.
--------- WP5 - TESTS AND TECHNOLOGY VALIDATION (AKRETIA) ---------
The objectives of WP5 were to perform the tests of the pilot reactor on a test bench, to evaluate the scale up of the reactor, to design a complete plant layout for the application into an industrial production, to qualify the process with respect to the economic competiveness, product quality and regulative issues, especially the compliance with TIER III and the eventual position of a new standard for the NOx abatement.
The activities related to this WP have regarded the performance of NOx efficiency tests for the evaluation of the effectiveness of the nanofibrous filter media in the abatement of the NOX by using an apparatus developed by NEXT, in respect of the technical requirements and limitations. NEXT in collaboration with LABOR has designed the final structure of the catalytic filters integrating ceramic nanofibres. Cubic module with 5 cm side including 20 layers of corrugated sheets and 18 layers of flat sheets to be used as spacers.
The module was assembled allocating different layers in the module envelop (realised by using an AISI stainless steel flat sheet) and it featured self-standing properties since no glue or welding of the different layer is foreseen.
TESTING PROTOCOL
The BLUESHIP test session took place at the facilities of the department of the Mechanical Engineering of University of Rome Sapienza, Italy. The BLUESHIP prototype described in D4.3 was installed in the mechanical workshop of the department, equipped whit a test bed integrating a 1.9 Multijet diesel engine of a FIAT Doblò van to which to prototype was connected. The testing protocol consists in the following:
- An engine speed (RPM) is set and the engine is stressed out (work on gear and brakes) to reach the temperature useful for the catalytic reaction (around 350-400°C);
- The initial NOx content is measured along the exhaust gas main stream. This value is inserted as input in the software which manages the measure;
- The measure starts in manual mode or automatic mode;
- The software, according the amount of NOx and the stoichiometric ratio, regulates the flow of urea for the catalytic reaction;
- A portion of the exhaust gases flow is directed toward the ES-SCR reactor by means of the manual partition valve;
- The catalytic reaction occurs inside the reactor;
- The amount of NOx is measured at the end of the by-pass line after the reactor to evaluate the reduction of nitrogen oxides occurred by means of the ES-SCR reactor.
The relative NOx value is registered by means of a NOx probe which provides the reading of the measure in form of a printed receipt where several parameters are reported, CO [%vol], HC [ppm vol], CO2 [%vol], O2 [%vol] and of course NOx [ppm vol]. Before starting the tests of the BLUESHIP SCR, a mapping of the emissions produced by the test engine was carried out. As expected the NOx emissions increase directly with the increasing of the speed of the engine. The control of the engine allows the users to set five different speeds: 800, 1500, 2500, 3500 and 4000 RPM.
TESTING PHASE
As described in the protocol, the first step of the testing phase consist into pushing the engine, until the desired temperature is reached, temperature between 350-400°C. At the beginning of the test the engine speed was set to 2500RPM, and after the engine reached 350°C, the NOx concentration was measured along the exhaust gases main line, reaching a value of about 1496 ppm.
Then the proportional valve was set to 20°, and the exhaust gas flow was directed through the ES-SCR reactor to be treated, and the NOx emission was measured at the end of the reactor. The value of 1495 ppm suggested that no catalytic evidence was present. In order to verify the truthfulness of the result, the test was repeated again also at different engine speeds. Regardless the engine speed or the test conditions, no evidence of catalytic conversion was observed. It was therefore decided to interrupt the test sessions to analyse the inside of the ES-SCR reactor to try to understand why the catalysis is not occurring as expected.
As a result, it was observed a complete detachment of the catalytic nanofibers from the corrugated and flat metal sheets constituting the catalytic elements, which made the ES-SCR reactor useless for further testing, having compromised the integrity of the catalyser and its functioning.
RESULTS OF TESTS
In relation of what emerged from the testing phase, the following assessments were made:
# Just after the calcination process, which is a thermal procedure occurring at temperature of about 500°C, a pronounced detachment of the nanofibers from the metallic support is observed. However, the entity of such loss in weight of deposited nanofibers was not so high to suggest a deactivation of the catalyser. Therefore the decision to use the metallic support in this form and shape was still in charge;
# The catalytic elements were produced by NEXT and delivered to LABOR for integrating them in the BLUESHIP prototype ES-SCR reactor. During the handling of the elements to put them in place inside the reactor, free powder production was still observed;
# The field test session described in the previous paragraph, unfortunately clarified that a thermal process is going to affect heavily the catalytic elements invalidating completely the adhesion between nanofibers and metallic support;
# During the testing phase, in addition to the thermal effect, a mechanical effect has also to be considered. In fact the engine causes a relevant vibration effect during its run, especially at higher engine RPM, that also affects the ES-SCR reactor, contributing to the detachment of the fibres;
# Another detrimental effect is that the detached fibres can be blown away from the reactor by the exhaust gases that go through the ES-SCR reactor and are lost with the discharge of the gases at the vent making the catalytic elements completely useless;
# The poor adhesion between nanofibers and support is due to the large shrinkage of the fibres during the calcination process as well as the different nature of the two constituents. For the latter, since the nanofibers have a ceramic nature while the support is metallic, during the heating process, the thermal expansion of the two materials is different and also during the cooling step they relax in a different way producing stress and strain phenomena that culminate with the wreckage between the materials.
In order to deal with the weaknesses emerged from the test, a new concept for the application of the catalytic fibres was discussed and implemented at lab scale, where a self-standing catalytic solution is pursued without the use of a support for deposition.
FUTURE DEVELOPMENTS
The concept behind the next step of activities is to evolve the application of the catalytic fibres towards a solution where the fibre forms a self-standing assembly of higher mechanical strength than the thin deposited layers. Since the main drawback in the original design stood in the coupling of materials with different properties, in the new solution the nanofibers were packed in to self-standing elements from the ES deposition to the calcination steps. The use of self-standing nanofibers has the following advantages:
1. At the calcination step, the material is free of shrink without the mechanical constrain of the substrate.
2. During operation, the level of porosity is controlled by the morphology of the fibres only. Tailoring on porosity of the nanofibers by orienteering and pattering has been shown in WP2.
3. Thermal mismatch between metallic and ceramic is avoided.
4. Mechanical failure of the fibres, due to the critical bending strain of the individual fibres can be avoided in thick depositions, where the thick elements have sufficient high stiffness to avoid bending on 1-2%, see D2.2 ad refs.
At this purpose two solutions were tested and developed at lab scale: the first step was to synthesize flakes of pure fibres, and the second step was to produce pellets of pure fibres.
By this solution, pellets and flakes can be used directly in the catalytic bed, without any external constrain and thus resist to mechanical stress and vibration. The pellet produced presented resistance to high porosity, around 60-70%, due to the interconnection spaces between the fibres. Stiff pellets can be handled and did not fail after sintering. This concept introduces the following advantages if compared to the previous solution:
# The metallic support is no more used - remarkable reduction in weight (>80%) and dimension of the catalyser (the use of stainless steel was obliged by the temperature to which occurs the catalytic reaction). During the calcination process the 10/11 of the energy was wasted to heat the metal whose role was purely structural and does not add any catalytic feature resulting in a reduction of energy costs.
# The self-standing pellet can be easily modelled - Before the calcination process, due to the presence of the polymeric chains, the flakes of fibres result easy to handle. They can be bended and therefore they can assume any shape according the needs of the application. Also after the calcination process, when the bulk of fibres has been consolidated in form and shape, there is room for further mechanical action, like making holes if needed inside the bulk by means of a drill thanks to the mechanical strength acquired by the bulk.
# The porosity of the pellet - The high porosity of the pellet does not obstruct the exhaust gas passage, therefore the new filter can be designed taking in account that the gas flow can be orthogonal to the filter being able to go through it, while in the previous application the gas flow forced tangential to the fibres due to the presence of the metallic support.
POSSIBLE APPLICATIONS
a) Packed bed solution: a well-known technology for filtration processes is the packed column; the bed can be constituted of different elements in form and shape according the application. The solid bed can be a bulk mass, solution applicable in applications where the tolerable pressure drop induced by the reactor is rather high, and also where the gas flow does not carry particulate or solid matter which would obstruct the bed. In case of exhaust gases it is preferable a solution where the bed is constituted by a bunch of pellets packed randomly, or presenting particular shape like the Rasching rings, or similar.
a) Improved honeycomb filter: to avoid heavy pressure drop values and obstruction issues, the easer way is to carve conducts to lessen the pressure, just like the honeycomb filters for de-NOx applications already do. The solution hypothesized introduces an innovation to the already existing and most used filter tech: the honeycomb filter. At the state of the art, a standard honeycomb filter is made of industrial ceramic by extrusion technology.
CONCLUSIVE REMARKS
The field test session of the BLUESHIP prototype allowed to point out the limit of the reactor layout designed in the project, which consisted of catalytic nanofibers deposited on a metallic support to realize a roll filter catalytic module. Just after the calcination process it was observed a detachment of the nanofibers from the support, effect which was magnified during the test session.
In fact before and after the test, no decrease of the NOx emissions was observed and the further analysis of the catalytic elements confirmed that the different thermal expansion of the ceramic nanofibers and the metallic support, both during the heating and cooling processes, ends with the wreckage of the elements with a huge production of free catalytic powder that is blow away with the exhaust gases flow.
In order to overcome this vulnerability, a new concept for the application of electrospun nanofibers without the use of a support was discussed. The innovation consists of a self-standing structure, where the nanofibers are self-sustaining without the use of any kind of support. This solution, developed at lab scale, offers the advantages of reducing considerably the weight of the catalyzer (>90%) of the catalyzer due to the absence of the metal; removing the support means also the reduction of the dimensions of the catalyzer and also during the calcination process the homogeneous of the catalyzer guarantee an homogenous relaxing process. No support means also a reduction of costs: no minor energy used to heat the metal.
At lab scale a pellet of nanofibers was synthetized. It presents a strong mechanical stability and a huge grade of porosity (around 60-70%) which makes it easy to handle and manufacture in different form (above all before the calcination process where the polymeric chains inside the fibres make them malleable). In this view, two hypotheses of application were considered: a packed bed solution where the replenishment of the bed is constituted of Ranching ring like catalytic elements made of nanofibers; and an improved honeycomb filter solution where the whole filter is made of catalytic fibres where the exhaust is able to go through the walls of the filter.
In order to prove the validity of this new concept, further tests will be carried out by the Consortium out of the timeframe of the BLUESHIP project, by using the prototype developed and the test bed implemented during the project. The work will consist into producing nanofibers disks to be placed inside the ES-SCR reactor, to realize a proof of concept reactor.
TECHNICAL AND ECONOMICAL ASSESSMENT
The tangible results produced during the project to be assessed are the following:
• Optimized synthesis and network patterning of functionalized fibres and production method at industrial scale
• SCR solution and test bench prototype of the BLUESHIP SCR
As a general consideration, the fibres developed have been confirmed to have the following advantages: a) Very high specific surface area of the active material: about 40 m2/g; b) High performance: better than conventional pure catalytic powders; c) Possibility to have textured components with rational, highly intricate, continuous, and open porosity. The use of electrospun fibres functionalized is expected to generate a relevant increase of the exposed active area in the SCR reactor, with subsequent decrease of volume and weight of the SCR unit. Given problems experienced in the deposition of the fibres onto a substrate, the method of synthesis will be pursued to produce self-standing catalytic mats for the application to SCR for both marine and automotive de-NOx. Reduction of the weight and size of the SCR is of paramount importance for ship and other mobile applications, e.g. light and heavy duty diesel engines.
The characteristics of the apparatus for electrospinning for production of large scale, optimized for nanofibrous ceramic catalyst were defined, and tested for the production at pilot scale, to be fully exploited for the production scale-up. The process parameters and operative conditions were optimized to ensure the best production of the nanofibres morphology (no or minor defects). The evaluation of scale up conditions and costs for production at large scale of catalytic nanofibers, through the scaled up industrial method implemented, were included in D5.2 which aims at assessing the industrial feasibility of the production.
A pilot prototype equipped with data acquisition and control system was designed, realized and installed in a specifically realized test bench capable to verify the NOx abatement on an automotive diesel engine. The pilot prototype was equipped with catalytic filters realized with BLUESHIP nanofibers deposed over corrugated /plain metal sheets representing the selected rolled filter configuration.
A model for the optimization of the geometric parameters of the reactor and the simulation of the fluid-dynamic behaviour was developed during the project, as well as calculation tool for the optimization of the exposed surface available for deposition in relation to the cell density of rolled filters. These were used for optimal dimensioning of the BLUESHIP SCR, and can be reused to simulate the behaviour of the SCR realized with self-standing catalytic nanofibers mats once the fluid dynamic behaviour of the solution will be tested and porosity known.
PRODUCTION COSTS
Production costs for the catalytic module was performed both in the case of the metallic supported substrate and the self-standing pellets.
# Metallic supported modules - assumptions
Production costs for 1 g of Catalytic Nanofibers supported on metallic substrate with a surface deposition of 1g/m2 have been computed for production of catalytic rolled filter module, considering the following assumptions:
• Precursors and polymer costs have been considered according to small scale selling price. A reduction at large scale is expected;
• Industrial costs for solvents have been considered according to quotation available from different suppliers in Italy;
• Energy costs in EU28 has been considered;
• Average personnel costs of 12 €/h (average for technician, according to LINARI staff costs). Annual salary gross and production capability has been considered;
• Energy for calcination has been computed by measuring energy consumption from pilot scale production
The analysis led to a total production cost considering CAPEX and OPEX at industrial scale for the rolled filter production of 9.93€/g.
# Self-standing nanofibrous flakes -assumptions
The same study has been carried out for the production of self-standing catalytic nanofibers produced at small scale within the proposal and that will be further investigated at pilot scale in the next months.
The production of 1 g (corresponding to 125 flakes of diameter 2.5 cm and thickness 0.2 mm) has been considered for the production of the self-standing catalyst. The assumptions that have been considered for the deposition of 1 g of nanofiber onto the metallic support are still valid.
Considering the same annual production, around 1,500,000 flakes can be produced per year, considering that the final OPEX and CAPEX costs are around 7.13 €/gr (0.06€ per flake).
FINAL SELLING PRICE
# Metallic supported modules
The final selling price is estimated considering a profit of around 40% (maximum price: 18.00 €/g). According to the final selling price of the catalytic filters, the expected turnover per year (assuming a linear distribution of the filter sales in the year) is estimated up to 216,000 € and a revenue before taxes of around 60,650 € at regime. The following assumptions have been done:
• The production of the first set of filter is starting one month before the sales;
• The payments is expected within 30 days after the sales;
• The annual depreciation costs have allocated at the beginning of the production.
• Total costs for the marketing and facilities costs have been considered around 30% of the total costs
The analysis conducted in T5.2 led to and expected selling price in the range of 15.0- 18.0€ in order to ensure a good profit out of the investment. The analysis is showing that at least 6,300g (corresponding to 2.4 industrial module with a total area of 2,650 m2) of filter must be sold in order to earn profits at the conditions described before.
# Self-standing nanofibrous flakes
As per metallic supported nanofibers, the final selling costs of 1 gr of flakes has been estimated considering an expected profit of 40%, meaning that the final price is expected to be 12.00€/gr (2/3 of the costs of supported material). A final turnover of around 144,000 € with a profit before taxes of 40,500 € is ensured.
The analysis is showing that at least 7,750 gr of flakes (corresponding to 967,000 flakes) must be sold in order to earn the profits calculated in D5.2.
POSITIONING AGAINST BENCHMARK
The average price of the selected honeycomb catalyzer module in large quantities is around 9,000-10,000 €/m3, according the current selling price provided by Emission Partner GmbH. Hence the typical price of the module in terms of exposed area available is around 15€/m2, considering the specific surface area data of the highlighted honeycomb system. When comparing the price estimated for BLUESHIP (> 18€/g or > 18 €/m2) and the price for honeycomb (15.6 – 17.3€/m2), price for unit of exposed area for BLUESHIP is almost the same than conventional module (+4-15%).
According to D4.3 expected catalytic area for nanofibrous catalysts (specific surface area = 961 m2/m3) at optimal condition is expected to be 2540 m2 (-20% compared to honeycomb) the total price for single industrial filter will be around 45,700 €, whilst the costs for the honeycomb reference is 29,700 € (-35%). However, it must be considered that the price could be competitive since:
1. the exposed area available from nanofibers can be considerably higher than honeycomb .
2. conversion efficiency is expected to be 2-3 times higher than the honeycomb benchmark
3. volume is 20% lower than the conventional honeycomb
TECHNICAL SPECIFICATIONS AND CONCLUSIONS
In order to perform a proper technical assessment of the BLUESHIP results, a list of specifications – taken from D1.2 of the project – was used in this task. For each domain of the project (SCR, electrospinning technique and nanofibres production), tables were created in D5.2 with the purpose of assessing the degree of achievement by the BLUESHIP technology. The scientific and technological results achieved in the research project are very promising: synthesis, performance and industrial scale up for production of catalytic nanofibers are beyond initial expectations in terms of catalytic conversion tested at lab scale. The production method to scale up production for an industrial production was implemented and process parameters optimized to ensure the best production of the nanofibres morphology (no or minor defects). The results achieved at present stage confirm that:
1. Ceramic nanofibres can be produced at pilot scale by using a needleless equipment. The process and system parameters have been optimized and no specific constraints have been identified for the scale-up.
2. SCR performance of the optimized NFs are equal or superior to the state-of-the-art wash coating.
3. Optimized morphology and composition can easily lead to NOx conversion above 80% at high gas hour space velocity (GHSV) of 400,000 h-1.
Deposition of nanofibers is realizable and repeatable with deposition rate of 3.6 +/- 0.3 g/m2. On the other hand, problems were encountered with the solution selected as supporting substrate for the deposition of the nanofibers for the production of the catalytic modules, due to detach of the nanofibers from the metallic substrate. This has caused the impossible industrial feasibility for the long-term behaviour of the nanofibers deposition on the metallic substrate.
Poor mechanical performance of the fibres mats can be solved by thick layers and multilayer mats. This alternative solution was pursued in the final stage of the project and realized in lab scale, producing self-standing catalytic flakes and mats. Tests of this solution at the SCR test bench prototype made available during the project are planned right after the end of the project.
--------- WP6 - EXPLOITATION, DISSEMINATION AND TRAINING (LINARI) ---------
Shipping is the backbone of international trade, some 90% of which is carried by sea. European ship-owners control 40% of the world’s merchant fleet and operate shipping services all over the world, including in trades between non EU countries, for instance between the Far East and Latin America.
Projections for this market indicate the volume of seaborne trade is expected to double from 9 billion tons per annum to somewhere between 19 and 24 billion tons by 2030. China will play a key role in 2030 as the emerging maritime superpower in shipping. China will see the largest growth in commercial fleet ownership, rivalling Greece and the rest of the European countries combined. China will become the world’s primary maritime market, leading in seaborne trade, shipbuilding and vertically integrated ownership and ship management.
A recently updated Oxford Economics study revealed the overall contribution of the European shipping industry to the European Union’s GDP at the end of 2012 was around Euro 145 billion. This demonstrates that the whole marine market is a very wide and fast evolving one.
The marine market, as a general consideration, holds the following features:
- It is a huge and extremely conservative market,
- It proves highly dependent on oil prices/fuel consumption volumes,
- It is subject to an increasing number of EU policies and regulations demanding for more efficient and less polluting solutions,
- Its players are mostly sceptic about renewable energy or new technological solutions’ reliability and efficiency for the application to the shipping segment.
With particular reference to the market of emission control catalysts, data derived from a market study from Frost & Sullivan (2013) show that:
The global emission control catalysts market is expected to reach $6,705.2 million by 2019 growing at a compound annual growth rate (CAGR) of 11.3% from 2012 to 2019;
The mobile emission control catalysts segment is the largest and accounts for 82% of the total market revenue;
The emission control catalysts market for diesel engines is gaining momentum with the emergence of heavy-duty diesel vehicle regulations. Hence, companies are beginning to focus on diesel engines to gain a competitive position in the market;
SCR, originally designed for stationary applications such as power plants, marine applications, and other stationary diesel engines, has gained momentum and is now being deployed even in light and heavy duty diesel engines.
ENVIRONMENTAL AND REGULATIVE ISSUES FOR THE MARITIME SECTOR
Despite the contribution of the shipping industry to environmental pollution proves reduced respect to other transport modalities, the European regulative framework, through the IMO Organization, has drafted several stringent indications that are forcing marine operators to concentrate on more efficient and less polluting solutions.
The global merchant fleet currently consumes approximately 330 million tons of fuel annually, 80-85% of which is residual fuel with high sulphur content, and the remaining are distillate fuels complying with stricter regulations. SOx, NOx and PM are all emissions to air that result from the combustion of marine fuels. These emissions have potentially severe ecosystem impacts and negative health effects on exposed populations. Emissions from the global shipping industry amount to around 1 billion tons a year, accounting for 3% of the world's total greenhouse gas (GHG) emissions and 4% of the EU's total emissions. Without action, these emissions are expected to more than double by 2050. This is not compatible with the internationally agreed goal of keeping global warming below 2°C, which requires worldwide emissions to be at least halved from 1990 levels by 2050.
The Commission's 2011 White Paper on transport suggests that the EU's CO2emissions from maritime transport should be cut by at least 40% of 2005 levels by 2050, and if feasible by 50%. However, international shipping is not covered by the EU's current emissions reduction target. At the same time as publishing a Communication setting out the strategy, the Commission put forward a legislative proposal to establish an EU system for monitoring, reporting and verifying (MRV) emissions from large ships using EU ports. The proposal would create an EU-wide legal framework for collecting and publishing verified annual data on CO2 emissions from all large ships that use EU ports, irrespective of where the ships are registered. Annex VI of the 1997 MARPOL Protocol has fixed the so-called Sulphur Emission Control Areas (SECAs) or Emission Control Areas (ECAs), that is, areas in which stricter controls were established to minimize airborne emissions from ships.
Alternative fuels have been used in the transportation sector in the past. Other fuels that could play a role in the future are Liquefied Petroleum Gas (LPG), Ethanol, Dimethyl Ether (DME), Biogas, Synthetic Fuels, Hydrogen (particularly for use in fuel cells), and Nuclear fuel. All these fuels are virtually Sulphur-free, and can be used for compliance with sulphur content regulations.
As already mentioned, since January 1, 2016 newbuildings intended for operation in the ECAs areas will have to comply with Tier III requirements set in the Marpol Annex VI, 2008. Feasible solutions to meet such requirements include:
- Exhaust gas recirculation (EGR)
- Selective catalytic reactors (SCR)
- Water injection – Humid air motors (HAM)/ Water in fuel /WIF) or
- LNG
Among these, the most promising remains selective catalytic reduction, which also embraces the scope of the BLUESHIP project. Selective catalytic reduction using ammonia as the reducing agent was patented in the United States by the Engelhard Corporation in 1957. Since that time thousands of systems have been installed on terrestrial applications, from power plants to locomotives or automobiles. SCR functions by combining ammonia, typically derived from an aqueous solution of urea, with a catalyst mounted on a ceramic monolith, to reduce NOx forming nitrogen and water. Today, SCR is in use in millions of vehicles and power plants.
Additionally, it is the only technology currently available to achieve compliance with Tier III NOx standards for all applicable engines (state of the art SCR systems are capable to reduce NOx emissions by more than 90% under certain conditions). The maritime sector has had more than two decades of experience with SCR, early implementations being made by MAN B&W and Wärtsilä.
Today, SCR is a relatively mature technology, widely used for NOx control in land-based industry and land-based transportation, and fitted to four-stroke medium-speed engines on a considerable number of ships in service (more than 1250 systems installed on carrier vessels in the past decade).
A number of manufacturing companies have invested in SCR in the 25 years since it was first applied to the marine sector. Currently, companies in Europe, the US and Asia are delivering marine SCR systems capable of meeting current and future NOx reduction requirements.
In the BLUESHIP Final PUDK Deliverable we have reported an analysis of the competitors for the new technology and of the market segmentation.
EXPLOITATION STRATEGY
The unique selling point of the system is to be the first cost effective, highly performing exhaust gas cleaning solution for combined de-SOx and de-NOx abatement available in the shipping industry, also allowing for retrofitting on launched vessels and capable of being even installed on small sized crafts. The technology is expected to have the following advantages in the specific marine application:
a. Very high specific surface area of the active material : about 40 m2/g
b. High performance: better than conventional pure catalytic powders
c. Reduced volume and weight
d. Reduced Total Cost of Ownership for the end user: increase of useful loading area (about 2k€/m2*y)
e. Possibility to have textured components with rational, highly intricate, continuous, and open porosity
The use of electrospun fibres functionalized is expected to generate a relevant increase of the exposed active area in the SCR reactor, with subsequent decrease of volume and weight of the SCR unit on board: reduction of the weight and size of the SCR is of paramount importance for BLUESHIP design and market in the ship and other mobile applications of emission control.
As already pointed out, the approach is to realize a new SCR to effectively meet the future demands of the shipping industry in order to propose the BLUESHIP system first of all to the marine sector, and then to move to other, potentially attractive target markets, also exploring synergies and partnerships with large industrial partners.
It is in fact interesting to evaluate that other possible applications for BLUESHIP SCR could emerge in other mobile emission control applications, e.g. light and heavy duty diesel engines. For instance, heavy-duty diesel engines have higher NOx emissions. SCR technology that achieves 95% NOx reduction is used in these engines. The option to implement further R&D activities to specialize BLUESHIP for this kind of applications is currently under evaluation inside the Consortium.
The results expected in BLUESHIP project are herein summarized and briefly described. BLUESHIP aims to realize an innovative De-NOx Selective Catalytic Reactor (SCR), specifically tailored to the marine shipping industry based on electrospun ceramic fibres, tailored in designed texture modules.
Despite the maritime application has been considered the target one, the potential market for BLUESHIP is really outstanding, due to the huge range of possible applications in several industrial sectors such as automotive, biomass boilers or thermoelectric power plants.
The results from the project are the following:
1. Optimized synthesis and networking patterning of functionalized fibres (PATENT WO 2015/169786 A1);
2. Fluid-dynamic simulation model and optimized design;
3. Optimized production process of functionalized catalytic fibres, and
4. Pilot prototype of the BLUESHIP SCR and results of testing.
The fourth result substantially consists in the integration of all the previous 3 results in the pilot prototype.
Result No. 1 state of development: in regards of this project result, at the end of the second period, the fibres chosen for the Selective Catalysis Reduction (SCR) of NOx, in both disordered and in oriented pattern, their catalytic characterization and performances of the different orientation of the nano-fibres to be used at the SCR, nonetheless their morphological, chemical characterization at lab scale and SCR performances at the material level, have been studied and defined.
Result No. 3. State of development: at the end of the project, all three deliverables have been submitted and the partners defined the characteristics of the needless apparatus for electrospinning for the production of large scale, optimized for nanofibrous ceramic catalyst currently present at the NEXT premises. In addition, the design of the ES-SCR and the physical prototype were implemented.
Results No. 2-4 state of development: At the end of the project reporting, the models and the concept design have been defined, the reactor and plant design layout with the required control system have been produced and the prototype implemented /tested.
The SMEs of the project will be respectively owners of the following foreground:
o AKRETIA, Results no. 1,2 and 4;
o LINARI, Results no. 1 and 3;
o STOGDA, Results no. 2 and 4.
With regards to patenting, a novelty search of the project results has been performed and reported in the D6.1 where the novelty of the project results and the possibility to protect the project results by the means of patenting has been assessed. The strategy for IPR protection has been discussed inside the Consortium.
A final decision on patenting was taken by the SMEs. Specifically, DTU was granted the possibility to patent the results of their research on ceramic nanofibres and to include partial results obtained under WP2 regarding the ceramic nanofibres of interest for the project BLUESHIP. This was done by establishing, in parallel to the filing of the patent, a free-licensing agreement between this RTD performer and the beneficiaries owning Result No.1 on the nanofibres synthesis. The details and the contractual agreements for the license have been reported in D6.3 Filing of patents, which also include the references of the patent and its full text.
The preliminary agreement established among the beneficiaries regarding the exploitation of the results produced in BLUESHIP reports the following indications:
1. LINARI will be the exclusive supplier of the BLUESHIP electrospun fibres and equipment to produce them;
2. AKRETIA will be the exclusive supplier of the BLUESHIP SCR system for maritime applications;
3. STOGDA will get a world-wide license agreement for the design and installation of the BLUESHIP in the naval sector.
The option to apply the results also in other sectors (SCR for automotive and stationary) will also be pursued directly by the SMEs or through licensing (in case of IPR protection). At M24, and according to the results achieved in the project, the SMEs have revised the exploitation strategy as follows, also stated the decisions done regarding patenting in general:
AKRETIA
Result/ Benefit from the project Exclusive supplier of the BLUESHIP SCR system for maritime applications.
LINARI
Result / Benefit from the project Licensee for the exclusive production of the BLUESHIP electrospun ceramic fibres tailored in designed textures module.
STOGDA
Result/ Benefit from the project Design and installation of the BLUESHIP on ships under commercial agreement with the other partners.
As evident from the description of the results and their achievement assessment (D5.1 and D5.2 on the results of field tests and the tech-economical evaluation), we can state that the scientific and technological objectives of the research are to be considered as achieved.
However, results on the SCR performance in reducing NOx and the efficiency of the overall unit still need to be improved in the view of obtaining a more attractive and mature technology, ready to work in a real environment. In fact, since the solution pursued using deposition of fibres on metallic rolled filters resulted not reliable at pilot scale, it was not possible to validate the efficiency of the electrospun SCR.
Plans for future steps required to achieve a more reliable proof of concept were defined, identifying a possible alternative route for the implementation of the BLUESHIP SCR using self-standing catalytic mats realized with the nanofibers, instead of metallic support for deposition. This route was pursued in the final stage of the project and realized in lab scale. Tests of this solution at the SCR test bench prototype made available during the project are planned right after the end of the project with common effort between SMEs and RTDs. After validation at prototype level, engineering and testing at relevant environment level will be pursued by the owners, through funding from potentially interested end users.
DISSEMINATION IN BLUESHIP
An important step for the realization of an effective dissemination plan is the understanding of what to disseminate of a project, how, when and above all to whom. In order to do this, internal discussions were held by the Consortium members to implement a dissemination plan, that is, a well-thought and systematic approach involving the identification of target potential adopters of the technology which is disseminated, and a list of actions – with related actors/partners performing them – considered of support in the transfer of the project outcomes to the selected audience.
In BLUESHIP, a preliminary dissemination plan was created at the beginning of the project; however, this was extended and revised in P2 to ensure continuous exchange of information related to the project results toward the external.
In this sense, dissemination was conceived as a continuously running task within the project.
Full commitment of the partners was put in:
- The interactions with both the scientific and the industrial world, whenever possible;
- The send-out of releases and articles disclosing all the non-confidential information and the details that the SMES decided to share for a proper promotion of the BLUESHIP technology;
- The monitoring of the activities carried out at a Consortium level in the view of refining/ improving the dissemination plan according to the feedback received when disseminating the project.
The main objective of the dissemination in the project is that of presenting the research work carried out in it and to inform any stakeholder about the state of development of the BLUESHIP solution. Additional, but not less important, objectives are related to raising awareness among the end-users about the potential impact of the technology and of describing its main features and advantages respect to state of the art solutions.
There are a number of maritime shipping stakeholders who might be interested in the BLUESHIP project results. These include, but are not limited to the following groups:
- Private sector representatives: ship-owners, shipyards, ship operators and managers, related industries such as shipbuilding or marine equipment;
- Governmental entities, regulators and policy makers in the maritime transport and in the environmental sector;
- Shipping industry (manufacturers);
- NGOs and academic institutions.
Among the several potential stakeholders mentioned above, some key ones have been identified for the BLUESHIP project:
PRIMARY AUDIENCE - Ship-owners, shipyards and designers
SECONDAY AUDIENCE - Maritime sector associations
The project dissemination plan foresaw the following steps:
Stage 1: Preparation phase. In Period 1, the Consortium prepared the way for a more intense communication step by introducing the project and launching its official start, diffusing news about its objectives and expectations. In this phase, dissemination materials were created to support the spreading of the project launch (press release, website, brochure, etc.).
Stage 2: Dissemination for understanding. Once the project has been initially presented and initial curiosity about its results and impact raised, the Consortium planned more targeted activities aiming at ensuring that end users and stakeholders are provided with technical features and details regarding the BLUESHIP technology demonstrating its commercial potential.
The main dissemination activities carried out at a Consortium level were reported in the Final PUDK Deliverable.
Potential Impact:
The unique selling point of the BLUESHIP is to be the first compact, highly performing exhaust gas cleaning solution for de-NOx in the maritime industry, also allowing for retrofitting on vessels and capable of being even installed on small sized crafts, due to reduce volume and weight and consequent reduced Total Cost of Ownership for the end user, due to the increase of useful loading area on vessel. The maritime sector has been considered the target application. However, the potential market for BLUESHIP is really outstanding, due to the huge range of possible applications in several industrial sectors such as automotive, biomass boilers or thermoelectric power plants.
The scientific and technological results achieved in the research project are very promising: synthesis, performance and industrial scale up for production of catalytic nanofibers are beyond initial expectations in terms of catalytic conversion tested at lab scale. The production method to scale up production for an industrial production was implemented and process parameters optimized to ensure the best production of the nanofibres morphology (no or minor defects);
On the other hand, problems were encountered with the solution selected as supporting substrate for the deposition of the nanofibers for the production of the catalytic modules, due to detach of the nanofibers from the metallic substrate. An alternative solution to produce self-standing catalytic mats was pursued in the final stage of the project and realized in lab scale. Tests of this solution at the SCR test bench prototype made available during the project are planned right after the end of the project.
The tangible results of the project, available to the SMEs for exploitation, are the following:
5. Optimized synthesis and networking patterning of functionalized fibres;
6. Optimized production process of functionalized catalytic fibres;
7. Fluid-dynamic simulation model; optimized design and test bench prototype of the BLUESHIP SCR
RESULT 1: Optimized synthesis and network patterning of functionalized fibres
For BLUESHIP project, TiO2-based catalysts for SCR applications were synthesized by a soft-chemistry method to form TiO2nanofibres, functionalized with V2O5 and with both V2O5 and WO3. Titania has been used as support for the catalyst (V2O5 and V2O5-WO3 oxides) and has been synthesized to have high surface area and the anatase phase. The synthetic path elaborated for the SCR consists in the formulation of a Ti-based sol-gel precursor to be used for the electrospinning of the fibres. Pure TiO2fibres can be synthesized and used as catalytic substrate for the functional elements to be added in successive steps. Another procedure adopted in the project includes the preparation of a starting solution added of individual or several the functional elements. In the latter case, the Ti-precursor was functionalized with the catalysts by dissolving the metals (V and V-W) directly into the TiO2 solution. This strategy is considered more valuable than other procedures, e.g. impregnation methods, where the catalysts are added by successive steps on the formed TiO2support. The main advantage of a direct dissolution of the catalysts consists in the fact that the elements result dispersed at the atomic level in the TiO2substrates, forming a highly active surface to the catalytic process. Moreover by this method the functionalized TiO2fibre is produced in a single step reaction at the electrospinning and a single calcination is the second and final step used to complete the fibres synthesis. The result was included in a wider patent application filed by DTU on “OPTIMIZED SYNTHESIS AND NETWORK PATTERNING OF FUNCTIONALIZED FIBRES” (WO 2015/169786 A1). License agreement with the SMEs owners was defined for the use of catalytic fibers for the application of SCR. The fibers have been confirmed to have the following advantages: a) Very high specific surface area of the active material: about 40 m2/g; b) High performance: better than conventional pure catalytic powders; c) Possibility to have textured components with rational, highly intricate, continuous, and open porosity. The method will be pursued by the SMEs to produce self-standing catalytic
RESULT 2: Optimized production process for functional catalytic fibres
The electrospinning solution applied within the project for the production of the nanofibres is a well-known technology. This technique involves the use of a high voltage to charge the surface of a polymer solution (or melt) droplet this to induce the ejection of a liquid jet through a spinneret or a flat surface. Within BLUESHIP project both techniques (needle and needleless technologies) were investigated at pilot scale in order to select the most proper technology to be used for the large scale production of nanofibrous catalyst.
Particular attention was paid to:
- The needle technology (LINARI is producing such a kind of devices) in order to define the most proper design (needle shape and distance) and to
- The geometry of the machineries in order to ensure a proper production of catalyst with diameter in the range 100 – 700 nm.
In fact, another major technical problem for mass production of electrospun fibres is the assembly of spinnerets during electrospinning. A straightforward multi-jet arrangement as in high speed melt spinning cannot be used because adjacent electrical field often interfere with one another. Accordingly, the array of the needles needs to be carefully designed to ensure that the electric filed strength at the tip of each needle is identical in order to produce samples containing uniform fibres.
The characteristics of the needleless apparatus for electrospinning for production of large scale, optimized for nanofibrous ceramic catalyst present at the NEXT premises were defined, and tested for the production at pilot scale, to be fully exploited for the production scale-up. The process parameters and operative conditions were optimized to ensure the best production of the nanofibres morphology (no or minor defects). The evaluation of scale up conditions and costs for production at large scale of catalytic nanofibers were calculated, through the scaled up industrial method implemented, assessing the industrial feasibility of the production.
RESULT 3: Fluid-dynamic simulation model; optimized design and test bench prototype of the BLUESHIP SCR
A model for the optimization of the geometric parameters of the reactor and the simulation of the fluid-dynamic behaviour was developed during the project, as well as calculation tool for the optimization of the exposed surface available for deposition in relation to the cell density of rolled filters. These were used for optimal dimensioning of the BLUESHIP SCR, on the base of which a final layout and design was created allowing for subsequent prototyping of the reactor and its testing at lab scale.
The preliminary layout of the BLUESHIP SCR reactor was conceived as a cylindrical packed bed reactor, with several cylindrical catalytic bed modules put in series, realised through deposition of the catalytic fibres on metallic rolled filter substrates. This solution was chosen to grant mechanical support for the fibres, that are fragile and need mechanical support, and to allow an easily industrially scalable production. Due to the problems of detachment of the fibres from the metallic substrate caused by differential thermal behaviour of fibres and support during calcinations and to the mechanical stresses, this solution was not successful. For this reason an alternative solution to produce self-standing catalytic mats was pursued in the final stage of the project and realized in lab scale. Tests of this solution at the SCR test bench prototype made available during the project are planned right after the end of the project. After validation at prototype level, engineering and testing at relevant environment level will be pursued by the owners, through funding from potentially interested end users (letter of interest from a large ship-owner was already got).
List of Websites:
The aim of the BLUESHIP website is to provide basic information, since the beginning of the project, to the external audience. It gives, in a very immediate way, an overview on the expected technical, operational and strategic objectives and on the relevant events in the addressed market.
The content of the web site is accessible to a general public in order to promote the exploitation of the project and research results. At the same time, the interested companies and the specialist audience will be able to establish contacts through the contact form. The address of the public website for BLUESHIP is the following:
http://www.blueship-fp7.eu/
A dedicated area for the project partners was provided, to be intended as project documentation repository.
Besides the project website, additional information and news on the project can be found at the LinkedIn showcase page at: https://www.linkedin.com/company/blueship-project.
The marine industry represents a competitive and strategic sector for Europe. With a market share of around 15% in volume terms, Europe is still at the top (with South Korea) for global leadership in terms of the value of civilian ships produced. For this reason, the European Commission has adopted in February 2013 the LeaderSHIP 2015 initiative, defining a strategic vision for the industry (innovative, green, specialized in high tech markets, energy efficient, diversifying into new markets etc.), with particular focus for maritime research towards zero emission and energy efficient vessels. In fact the volumes of waterborne transport are rapidly increasing and now account for close to 50% of intra EU of freight volume (DG TREN Data). Under current growth trends, emissions from international shipping in European sea areas are projected to increase by nearly 40% between 2000 and 2020. If no additional abatement measures are taken, by 2020 the emissions from shipping around Europe are expected to equal or even surpass the total from all land-based sources in the 27 EU member states.
NOx emission standards for international shipping are set by the International Maritime Organization (IMO). New regulations were introduced by the IMO in 2008 (MARPOL Annex VI): the IMO Tier III requirements reduce nitrogen-oxide emissions (NOx) by approximately 76% in comparison to a Tier II engine and applies to new vessels and engines built after 1 January 2016 when sailing in Emission Control Areas (ECAs). This poses a significant challenge to engine designers, as they need to apply NOx-reduction measures.
The only technology that presently allows to comply with TIER III is Selective Catalytic Reactor (SCR), presently equipped with a catalyst bed realised through honeycomb monolithic units. The monolith is manufactured by extrusion technique starting from ceramic-polymeric blends generally with use of pore-formers.
The BLUESHIP project aims to realize an innovative de-NOx SCR specifically tailored to the shipping industry, based on electrospun ceramic fibres tailored in designed textures modules, meant to replace the existing monolithic honeycomb design, granting reduced size and weight of the system, installation and operational costs, when compared to the state of the art technologies.
The specific objectives of the project were:
• Synthesis and fabrication of V-W-TiO2 fibres in different morphologies and functionalization,
• Characterization of the materials with respect of the De-NOx reaction,
• Modelling of the fluid dynamic inside the reactor and optimization of the design,
• Design of the reactor concept,
• Optimization of electrospinning deposition technology for production of functionalized catalyst fibres,
• Implementation of a pilot application and testing in a test bench,
• Validation of the technology and evaluation of scalability.
The consortium of the BLUESHIP project is composed by the following SME partners: STOGDA Ship Design and Engineering Spz.o.o from Poland; AKRETIA GmbH from Germany, LINARI Engineering Srl from Italy, and the following RTD centres: Labor Srl from Italy, Danmarks Tekniske Universitet from Denmark and Next Technology Tecnotessile from Italy.
Project Context and Objectives:
According to the work plan outlined in Annex I of the Grant Agreement, the BLUESHIP project has been devoted to achieve the following strategic goals:
• S.01 – Reduce the size and the weight of the De-NOx SCR by 50% with respect of the state of art SCR; for installation and retrofit in existing ships, and for possible integration into De-SOx units;
• S.02 – Reduce the consumption, need of purchase and costs of reactants (ammonia or urea) of 20%;
• S.03 – Reduce the installation costs by 20%;
• S.04 – Reduce the operation and maintenance costs of 15%.
The following operative objectives have been pursued to achieve such goals:
• O.O.1 – Synthesis and fabrication of TiO2, V2O5 and WO3 fibres in different morphologies and functionalization;
• O.O.2 – Characterization of the materials with respect of the DeNOx reaction;
• O.O.3 – Modeling of the fluid dynamic inside the reactor and optimization of the design;
• O.O.4 – Design of the control system for optimal operation of the reactor;
• O.O.5 – Optimization of the electrospinning deposition technology for production of functionalized catalyst fibres;
• O.O.6 Implementation of a pilot application and testing in a test bench;
• O.O.7 – Validation of the technology and evaluation of the scalability.
The BLUESHIP project ultimately aims at implementing a compact, light and efficient De-NOx SCR specifically tailored to the need of installation or retrofitting on board of ships, to be integrated with state of the art De-SOx for a complete exhaust treatment and emissions abatement.
The project is expected to generate the following tangible results, available to the SME partners for exploitation:
1. Optimised synthesis, fibre network patterning of functionalized fibres by electrospinning techniques for SCR,
2. Fluid dynamic simulation model and optimised design of the electrospun SCR for shipping application;
3. Optimised production process of functionalized catalytic fibres through electrospinning for the SCR application, and
4. Prototype of the BLUESHIP SCR and results of testing.
The proposed technology is expected to have several advantages for the end-users, among which the most valuable have been considered the reduction in the size of the system meeting the current space demands on board, the integration of De-NOx into De-SOx plants to implement a complete exhaust gas treatment device, increase of the mechanical strength due to reinforcement of catalysts materials and the reduction of transport and purchase costs sustained for urea/ammonia in existing devices.
The project activities have been defined to reach an easy and effective structure:
WP1, WP2, WP3 and WP4 – RTD activities
WP5 – DEMO activities
WP6 – OTHER activities
WP7 – MNGT activities
The project work led to the following main results:
1. Selection of a reliable and effective synthetic method for production and low control process conditions of V-W-TiO2 fibres to be used for the Selective Catalysis Reaction of NOx, reporting their characteristics in terms of morphologies and chemical compositions, as well as assessing their catalytic performance at lab scale SCR;
2. Definition of a solution for the support of the electrospun fibres for the implementation of the catalytic module and of the SCR reactor, testing and characterising their fluid-dynamic permeability;
3. Dimensioning of the BLUESHIP SCR for the target marine application specified in the first stage of the project;
4. Verification through specifically designed simulation model of the pressure losses, gas velocity and the yield of reaction inside the dimensioned reactor.
5. Design and implementation of a pilot scale BLUESHIP SCR prototype equipped with specifically realized catalytic filters realized with nanofibers deposed over corrugated /plain metal sheets representing the selected rolled filter configuration; installation of a test bench facility for the evaluation of the performance on an automotive diesel engine;
6. Field testing of the prototype, assessment the results and definition of plans for future steps required to achieve a more reliable proof of concept were defined, identifying a possible alternative route for the implementation of the BLUESHIP SCR using self-standing catalytic mats realized with the nanofibers, instead of metallic support for deposition.
7. Identification of the electrospinning technology to be used for the production at pilot scale and needless, to be fully exploited for the production scale-up and optimization of the process parameters to ensure the best production of the nanofibres morphology (no or minor defects);
8. Conduction of a technical-economic analysis of the efficiency of the catalytic nanofibers and their production costs through the scaled up industrial method implemented, assessing the industrial feasibility of the production.
9. Implementation of the dissemination plan and IPR protection strategy, including patenting of the method for the synthesis of the fibres and definition of a joint exploitation approach to be followed after the end of the project.
Project Results:
--------- WP1 - DEFINITION OF SPECIFICATIONS (STOGDA)---------
The first work package of the project was dedicated to the collection and the definition of the user requirements for the BLUESHIP project and the definition of the technical specifications and a preliminary layout of the final system. This work package started at month 1 of the project, being planned to last 3 months, in order for all partner to gather all the necessary information related to the user-requirements and the definition of the system specifications. The specifications will then be used to guide the research and the design activities and to assess whether the system that will be developed in the project meets the established requirements. This work package is concluded with the submission of the deliverables foreseen by the work plan.
IDENTIFICATION OF REQUIREMENTS
This activity was mainly carried out main by the SMEs (STOGDA, AKRETIA and LINARI), who identified a complete set of requirements and constraints from the end users side for the implementation of the SCR system, the nanofibres and the electrospinning process requirements. This in order to define the initial framework and targets of the project and put the basis for the definition of the technical specifications and components outline.
In particular, the main result of this activity was the identification of:
o The Regulatory Framework, defining the current EU and International regulations, especially focused on the MARPOL convention, that impose limits of emissions to the marine industry, in order to protect the environment. This is a relevant point for the project, being this regulatory framework the main driver for the need of the BLUESHIP technology.
o The benchmark for the SCR technology, with identification of existing technical solutions, limits and constraints, to be considered as technical and economical reference for the BLUESHIP solution.
o User requirements and external constraints for the implementation of the new SCR system, with selection of the target vessels, motor, oil, exhaust gas cleaning system for BLUESHIP.
o Requirements for nanofibres and electrospinning process, with selection of the manufacturing process, currently applied machinery, and the manufacturing of the nanofibres, which implies the best precursor selection for new SCR system, nanofibres morphology and patterns choices and selection, as well as its costs overview.
The SME have joined their visions and experience to define the different aspects of the requirements for the integration of the SCR system, the nanofibres and electrospinning process.
The technical discussions established within the Consortium in the very first part of the project allowed to define the benchmark solutions and to identify the requirements and targets for BLUESHIP to be competitive in the market, both from the technical and economical point of view.
The reference engine, vessel and fuel have been selected to identify the constraints, which the system will have to deal with. The target for NOx removal to deal with the upcoming regulatory framework has been defined. The needs and limits for the integration onboard of BLUESHIP SCR have been defined. The necessity of integration with the commercial dry De-SOx system provided by AKRETIA has been considered.
On the other hand, the requirements for the electrospinning equipment for the production of the nanofibres to be used as catalyst in BLUESHIP SCR have been defined.
As a conclusion, a complete set of requirements from the end user point of view, according to the industrial partners’ needs, have been identified and collected in a joint work.
The methodology applied for the collection of such requirements proved efficient and intuitive, and the immediateness of the requirements setup process, as it was suggested, made the involvement of the entire project partner easy, allowing for fruitful exchange of information and requests among the beneficiary SMEs and the RTD performers.
The outcome of the work is included in D1.1 and led to a shared vision of what the SCR reactor will have to perform, and of what it will have to be like, in order to be competitive and bring innovation in the addressed markets.
REGULATORY FRAMEWORK
The regulatory framework has been outlined, consisting in evaluation of the current EU and International regulations, especially focused on the MARPOL convention, that impose limits of emissions to the marine industry. This is a relevant point for the project, being this regulatory framework the main driver for the need of the BLUESHIP technology.
The most important regulation as relevance for the project is the MARPOL convention. The MARPOL agreement has been reached in the 1997, on an air-pollution annex to the International Marine Organization (IMO) MARPOL Convention – Annex VI. In particular Regulation 13 relates to “Nitrogen Oxide (NOx), emissions from diesel engines”.
This regulation 13 contains further a 3-Tier approach. To comply with Tier III, ships constructed on or after 1 January 2016 will have additional limitations when operating in an Emission Control Area. For the purpose of NOx emissions no Emission Control Areas (ECAs) have yet been designated, but it is expected that both the Baltic Sea and the North Sea will be designated well ahead of 1 January 2016. For Tier III ships operating in the NOx ECAs the allowable emissions of total weighted NOx depending on engine speed are:
• 3,4 g/kWh when n is less than 130 rpm
• 9,0 × n(-0,2) g/kWh when n is 130 or more but less than 2000 rpm
• 2,0 g/kWh when n is 2000 rpm or more
TECHNICAL BENCHMARK
The SCR technology has been analysed, its fields of traditional application evaluated and the main competitors listed. The design criteria and parameters have been identified and technical constraints evaluated.
The SCR for the marine application has been studied and the main parameters for the design of the reactor with respect with the catalyst are:
• Choice of catalyst as a function of the degree of conversion to be obtained
• Cell size of the catalyst in relation to the load losses and the efficiency of the catalyst
• Porosity and permeability of the catalyst
Regarding the process variables:
• Temperature of the flue gas line
• Operating pressure inside the reactor
• Composition of current flow into the reactor
• Degree of conversion desired
• Residence time in the reactor, and the inverse value defined as space velocity
The economic aspect was evaluated for standard SRC application as a reference for BLUESHIP. Fixed costs include initial capital and installation costs for the equipment. The major operational costs are those of the reducing agent (urea). The calculation tool recognizes that any fuel penalties which arise due to pressure drop across the SCR system are offset because a fuel optimized engine with an SCR system allows for a fuel efficiency benefit. Fuel savings can reduce the cost of SCR technology. Cost of a benchmark SCR were calculated for the for selected engine 6L27/38 for Tier II standard.
APPLICATION REQUIREMENTS AND EXTERNAL CONTRAINTS
The constraints for the application of BLUESHIP were defined, including:
• Marine fuel (heavy fuel Oil) HFO (up to 700 cSt/50° C, RMK700) MDO (DMB) _MGO (DMA, DMZ) according ISO8217-2010. Suggested fuel: Marine fuel ISO RMK 700 acc. to ISO 8217 classification.
• exhaust gas composition
• Reference vessel: new general cargo / 108TEU container vessel,
• Main Engine: 6L27/38 engine produced by MAN Diesel & Turbo (four stroke type, considered the most prevalent engine in the entire world).
• Arrangements for the exhaust gas cleaning system
• NOx content removal target: in ECAs regions for engine 6L27/38 acc. TIER III is 2.4 g/kWh,
• the pressure drop and velocity of the gas,
• The minimum temperature which for the selected engine, temperature of exhaust gas after turbocharger is 360°C.
The aim of the reactor design is also focussed at easy mounting procedure and easy monitoring of the chemical process efficiency and easy replacing of the wearied and or damaged part of the reactor, nonetheless that the SCR breakdown and maintenance cannot influence the continuous equipment and ME functioning.
NANOFIBRES AND ELECTROSPINNING PROCESS REQUIREMENTS
Different processes for production of fibres were analysed.
Manufacturers of electrospinning equipment have been listed and the existing commercial equipment evaluated for the needs of BLUESHIP fibres production.
Requirements related to the nanofibres and electrospinning process have been evaluated, consisting in:
• Shape and size of the fibres to be produced.
• Functionalization required
• Production capacity
• Economic requirements
TECHNICAL SPECIFICATIONS AND LAYOUT
This activity was mainly carried out by the RTD performers (LABOR, DTU and NEXT), who defined the technical specifications of the system and a preliminary layout of the final system.
In particular, we obtained the following results:
o List of the technical specifications for the 3 main groups, each coordinated by one RTD performer, dealing with: 1. Selective Catalytic Reduction process and reactor (LABOR), 2. Electrospinning process and apparatus for the production of nanofibres (NEXT), 3. Nanofibres used as catalyst (DTU). The deliverable provides a univocal identification of each technical and non-technical specifications, produced by the RTD performers on the basis of the functional requirements provided by the SMEs. It must be considered that the process of translation of the requirements into specifications has been realized through the following process.
o Preliminary layout of the reactor and of the technical choices to be used for the design and implementation of the BLUESHIP SCR reactor and plant. Concerning the choice of the solution for the deposition of the nanofibres for the production of the catalytic bed, the rolled filter support was identified as preferential option. The rolled filters, usually applied for diesel engine exhaust filters, consist of a planar element and a corrugated element bonded together one on top of the other. The resulting bi-layer is then tightly rolled to form a cylindrical filter with defined channels, which are related to the geometry of the corrugated element. This solution presents the advantage of allowing a continuous production directly coupled with the electrospinning deposition, it gives the possibility to modify the space of channels and then the permeability and active surface of catalyst. It can also be easily unfolded for regeneration and cleaning. The preliminary layout of the BLUESHIP SCR reactor is conceived as a cylindrical packed bed reactor, with several cylindrical catalytic bed modules put in series. The SCR reactor is included into a complete exhaust gas cleaning system (ECGS) plant layout. The arrangement identified for the BLUESHIP EGCS was defined for both low sulphur and high sulphur fuels usage.
A coherent set of specifications elicited by the Application Scenarios and the User Requirements has been overlapped and blended with the RTD Performers’ point of view, technology constraints, and stakeholders’ thoughts.
The work is concluded with the definition of the specifications for the BLUESHIP system (reactor and plant, nanofibres to be used for the catalyst and electrospinning apparatus for their production) and the definition of the preliminary technical choices for its implementation.
The specifications will then be used to guide the research and the design activities and to assess whether the system that will be developed in the project meets the established requirements.
Concerning the choice of the solution for the deposition of the nanofibres for the production of the catalytic bed to be used in the SCR, the rolled filter support was identified as preferential option. The rolled filters, usually applied for diesel engine exhaust filters, consist of a planar element and a corrugated element bonded together one on top of the other. The resulting bi-layer is then tightly rolled to form a cylindrical filter with defined channels, which are related to the geometry of the corrugated element. This solution presents the advantage of allowing a continuous production directly coupled with the electrospinning deposition, it gives the possibility to modify the space of channels depending on the way of packing the rolled filter (spacer between two layers), it can be easily unfolded for regeneration and cleaning. Several solutions for the choice of the geometry and for the material to be used for the support were identified and will be tested in lab in the next steps of the project.
The preliminary layout of the BLUESHIP SCR reactor is conceived as a cylindrical packed bed reactor, with several cylindrical catalytic bed modules put in series. The SCR reactor is included into a complete exhaust gas cleaning system (ECGS) plant layout. The arrangement identified for the BLUESHIP EGCS was defined for both low sulphur and high sulphur fuels usage.
This can be modelled as a plug flow reactor (PFR, sometimes called continuous tubular reactor, CTR, or piston flow reactors), which is commonly used to describe chemical reactions in continuous, flowing systems of cylindrical geometry.
The relevant parameters for the design of the reactor are:
• The length of each catalytic bed module (L) is fixed and the dimension is constrained by the electrospinning maximum deposition width.
• The diameter of the catalytic bed (D) and of the reactor will be defined according to the desired gas velocity inside the reactor.
• The number of modules (n) will be defined according to the required conversion efficiency of the reactor and the conversion per volume of catalytic bed.
The SCR reactor is included into a complete exhaust gas cleaning system (ECGS) plant layout. The arrangement identified for the BLUESHIP EGCS was defined for both low sulphur and high sulphur fuels usage. Two layouts were identified in this WP:
- Version A: in case a low sulphur fuel is used, it can be applied without a De-SOx and should substitute the silencer in the on board layout. This could be used for worldwide sailing vessels;
- Version C: in case a high sulphur fuel is used, a dry scrubber for De-SOx is used before entering the SCR. This could be used in vessels periodically navigating in the ECA areas and using high sulphur fuels.
In both cases, a safety bypass has to be applied to the SCR, to be used in case of maintenance and to bypass SCR when outside the ECAS regions. Summarizing, the preliminary layout of the BLUESHIP SCR reactor is conceived as a cylindrical packed bed reactor, with several cylindrical catalytic bed modules put in series.
--------- WP2 - SYNTHESIS AND FABRICATION OF CATALYST FIBRES (DTU) ---------
SYNTHESIS
SCR materials in the shape of nanofibres were synthesized by a sol-gel based method obtaining different morphologies with some differences in terms of catalytic activities. An important factor that to be considered in the electrospinning process was the up-scalability of the synthetic chemical route for the production of large quantities of fibres. This can influence the compositions as well as the morphologies obtained at the final product.
A basic chemical route was developed on the mixed use of Ti-alkoxides and salts/oxides of the catalysts. This method is feasible at the lab scale and it is very promising for the large scale.
Other crucial factors considered were stability of the starting solution, the presence of water in the process and a homogeneous incorporation, i.e. dissolution, of the catalysts (V and W) in the TiO2 anatase phase. These can also influence the morphology of the product. Small amount of water also leads to some changes in the morphology and presence of flaws in the material.
The following key-activities were carried out:
1. Optimization of the starting solution formulation as amount of acetic acid which is used both as catalyst of the chemical reaction and ligand agent. Acetic acid has a large influence on the stability of the starting solution, as well as, on the rheological features for the electrospinning process and thus on final morphology of the fibres.
2. Development of a synthetic strategy for a controlled use of deionized water in the starting solution. Water is added to the starting solution to prevent detrimental effect of high humidity in the ES deposition environment. In this context, water was added in a form that, together with the ligand agent, it could be used at the electrospinning for prolonged spinning time before flocculation due to polymerization of the alkoxides.
Acetic acid is used in the synthetic method as a fundamental component to stabilize the alkoxide precursors in the starting solution. In metal alkoxide chemistry (i.e. sol-gel), acetic acid is mainly used as acidic catalyst which activates the linear polymerization of the alkoxide via a low pH hydrolysis-condensation steps. On the other hand, acetic acid is also a chelating agent (i.e. a ligand) which can polarize the individual alkoxide molecules, inhibiting hydrolysis and condensation with formation of stable acetate-metal oxide complexes. However, an excess of acetic acid can also lead to complexation and precipitation of organometallic compounds. These complexes are more difficult to be hydrolyzed and they can even precipitate in the solution because they have poor solubility in alcohols.
The basic method includes the preparation of a starting solution based on titanium isopropoxide (TIP), vanadium acetate (V-AC) and tungsten ethoxide (W-ET) in Ethanol (99 %) in anhydrous conditions. In the basic formulation, no water content in the staring solution was added, to avoid uncontrolled hydrolysis and condensation of the starting alkoxides before the electrospinning process. Acidic catalytic conditions, by use of acetic acid, were used to promote linear polymerization of the alkoxides. For the lab scale, the starting solution preparation steps were:
- A small glass flask (25-50 ml), equipped with a rubber stopper, is connected to an Ar (or N2) pipeline. The inert gas is fluxed during the entire process to avoid presence of water within the reactor. The different (liquid) compounds are added using syringes as the rubber stopper can be easily punched;
- Acetic Acid is added in the Ac/Ti ratio: 2, 5, 10;
- The required amount of Titanium alkoxide is added. The solution is kept under magnetic stirring;
- The required amount of Tungsten alkoxide is added;
- The required amount of Vanadium oxyacetalacetone-ethanol solution is added. Such as solution must be prepared in advance.
- The required amount of PolyVinylPyrrolidone (PVP) ethanol solution is then added. Again, the PVP ethanol solution must be prepared in advance.
Optimized electrospinning conditions were:
• Constant Nozzle-target distance of 12 cm
• Applied voltage 36 KV
• 20-22 RH%
• 28-30 °C
• feeding rate 1ml/h
All the materials were calcined at the same conditions, i.e. 400 °C for 3 hours. The nominal composition of the fibre analyzed in the study was: V0.03W0.04Ti0.93O2-x. The use of water in the starting solution is a convenient option for the production of fibres in large scale, where a limited control of the electrospinning environment is expected or desirable.
This is due to the fact that metal alkoxides are chemicals which easily react with water undergoing to hydrolysis and condensation and uncontrolled polymerization on metal oxo-hydroxo compounds. The latter are irreversibly formed in solution and lead to gelification of the starting solution with increase viscosity.
CORE-SHELL FIBRE
With respect to the objective (to investigate two different morphologies: porous fibre and core-shell fibres, as requested by the SMEs the core-shell morphologies have been not investigated because not compatible with the needle-less equipment adopted by the consortium along the project. According to the contingency plan other composites made of nano-particles as starting materials have been investigated by a “hybrid sol-gel” chemical method (HSG).
The core-shell morphology was meant to obtain composite fibre morphology, where the core is made of a material with selected functionalities, e.g. catalytic substrate or mechanical strength, and the shell is the catalyst. This core-shell morphology can be made by co-axial needles electrospinning equipment, which, however, cannot be used for large scale production. Due to this limitation, an alternative morphology based on the use of nanometric powders on the catalysts was investigated. Conversely, to the core-shell, this can be produce starting from a single solution and it does not require co-axial needles equipment. Moreover, the results obtained indicate a feasible methodology to produce nanofibres with cheaper starting chemicals and easier control of the process.
Use of catalyst nanoparticle as constitutive precursor of the fibres has been carried out for the case on WO3. The results reported here are also applicable to the case of a direct incorporation of V2O5 or both WO3 and V2O5 nanoparticles. This method consists in the direct incorporation of some of the metal oxide constituents (e.g. WO3) as nanoparticles in the sol-gel starting solution. By this method, the metal oxide particles result embedded in the fibre precursor at the electrospinning. The fibres are then crystallized into the metal oxide matrix composites after the calcination step. The schematic representation of the process involves:
a. the nano particles are dispersed in starting solution;
b. the solution is spun into a PVP based fibre including the particles and the matrix precursor;
c. the fibre results in a composite of all the constituents after calcination.
REMARKS ON THE SYNTHETIC METHOD AND OPTIMIZED MORPHOLOGY
Activities in WP2 have demonstrated the feasibility of the proposed synthetic strategy for the formulation of co-doped TiO2 nanofibres for SCR application. Particularly:
1. The state-of-the-art synthetic procedure proposed for the pure TiO2 nano fibre has been extended in BLUESHIP to the complex formulation of co-dope V2O5-WO3 catalysts on TiO2 by calibrated use of alkoxides (i.e. W-ethoxide), metal salts (i.e. V-Acetate) and a ligand agent (Acetic Acid). This was done for the first time in this project for the synthesis on Electrospun nanofibres.
2. Use of ligand as chelating agent is a viable method to control the reactivity of the alkoxides reactivity during the process and it allows using a control amount of water, even in the starting solution. This fact creates a solid basis for the industrialization of the nanofibre synthetic process, especially for large scale production, where stability of the starting solution during processing and storage is a crucial factor.
3. Final morphology of the fibre is mainly affected by the quality of the starting solution and how the reactive surface area can be tuned by the process. In the BLUESHIP framework, the activities in WP2 have shown that an optimization of the process is possible and desirable to achieve the best SCR performance from the fibres.
Beside the different morphologies obtained, all the material tested presented fragility and their direct exposition to the mechanical stress and vibrations in the final BLUESHIP application would lead to a failure of the fibres. On the other hand, the core-shell design, where the mechanical strength is at the core of the fibre, cannot be considered as an option because this kind of fibres cannot be produced in large quantities in the consortium.
SCR CHARACTERIZATION
The evaluation of the catalytic performance (SCR) was carried out in conformity to the state of the art experimental setup.
The SCR lab-scale reactor consisted in quartz glass tube in a tubular furnace equipped at the outlet with sensors for NOx and CO, NO supply (bottles and MFC) and gas analyzers (mass spectrometry (MS) and chemi-luminescence detector (CLD)). The composition of the outlet gas is analysed with a quadrupole mass spectrometer (MS) Omnistar GSD 301 from Pfeiffer Vacuum and a chemiluminescence detector (CLD) Model 42i High Level from Thermo Scientific. The CLD can detect NO, NO2 and NOx, all nitrogen oxides were registered as NOx. The MS was used measure the concentration of NO, N2, CO2 and O2, with the limitations reported in D2.2. Freestanding nanofibres samples were extensively characterized in a lab-scale reactor able to control critical parameters such as temperature, ammonia concentration, presence of water etc. This enables to estimate and compare the performance of the materials produced in the different conditions. The key-parameters in the catalytic character of the fibres are:
1) the composition of the catalyst,
2) the phase at the TiO2 substrate, and
3) the fibre morphology (i.e. the porosity and the specific surface area).
The TiO2-V2O5-WO3 with high catalyst contents (e.g. V2O5-WO3 above 1.5 % in weight) can easily give full NOx conversion (i.e. 100 % conversion of NOx into N2), especially at the high temperatures above 300 °C. In this work, the amount of samples used at each test is only 20 mg for a flow of 6 L/h. Such small amount of catalyst leads to conversion degree that rarely exceeds 90% even at the high temperatures (e.g. 400 °C). This choice allows estimating the effect of the slight changes in conversion degree due to variation of the microstructural features of the nanofibres. The lab-scale SCR characterization device is describe in detail in D2.2.
FIBRE – NETWORK PATTERNING
Alignment and patterning of the fibre can be an important factor to vary the catalytic activity and the dynamic of the fluids in at the SCR reactor. Oriented or random fibre result in different reaction kinetics as well as in a different distribution of the fluids (both reactants and reagents) at the reactor. However, while random fibres are easily produced, oriented fibres usually required high rotational speed at the fibre collector or special pattering at the collector. The high rotational speed at the collector is usually used in needle-based ES equipment and thus is difficult to up-scale. Conversely, using a patterned substrate can lead to a preferential orientation of the fibres during the electrospinning. However, in this case the alignment is determined by the substrate geometry and by the configuration of the electrostatic field on it during the electrospinning process.
The planned work was originally devoted to design simple patterned network realized by the use of rotating drum collector which allows wrapping the spun fibres with a selected orientation by rotating the collector. The up-scalability of the fibre production is found to be a critical point in the technological transfer of the produced fibres to the industrial level, as none of the commercially available large scale electrospinning equipment allows high speed motion at the collector such to allow fibres orientations. The deviations in the R&D activities have been carried out on the track of the technical risks assessment and mitigation and have been discussed and approved by all the partners at the steering meetings.
Orientation by drum collector rotation
Randomly oriented fibres are easily formed at any rotational speed below 50 rpm at the large collector (8 cm), i.e. relative speed between the nozzle and the collector below ca. 20 cm/sec. On the other hand, a few examples of microstructures obtained tuning such operation conditions are reported.
The use of very fast rotational speed was also tested as high as 2000 rpm on collector of 0.3 cm was tested to check the limits of the technique (relative speed ca. 30 cm/s). SEM observation showed, however, that the material results compact and several preferential orientations in the different parts of the sample. The materials resulted locally aligned and very defective with several beads, broken fibres, agglomerated particles and entanglements. The conclusion about the use of high rotational speed for the fibre alignment is that rotating collector can impose a preferential orientation to the fibres when the relative speed is above 100 cm/s. However, the materials also result randomly oriented and very fast rotations at the small collector can lead to undesired lateral motions such as vibrations and wobbling, leading to defects, heterogeneous fibres organization and lack of long range orientation.
Orientation by patterning
Since the use of fast rotational relative motion between nozzles and collector is difficult or even unfeasible in the large scale ES equipment, an alternative strategy was elaborated to obtain oriented fibres. Patterned counter-electrodes are known to impose a preferential orientation to the deposited fibres. This is due to the fact that the electrostatic filed is preferentially distributed on electronic conductors and not on insulating materials. Therefore, during the electrospinning process the spun solution targets the metal collector and not the insulating material. The result is that the fibres are deposited along the metal collector, reproducing its geometry, as well as across the insulating parts creating ordered depositions. The meshes used were mainly of two kinds:
1. Expanded mesh: this is an mesh made by shearing a metal foils in a press, so that the metal stretches, leaving diamond-shaped voids surrounded by interlinked bars of the metal
2. Wired mesh: this is a conventional mesh done by waving metallic wires defining squared apertures.
As result of the geometrical shaping, the expanded mesh presented fibres with a dominant orientation along the longer side of the apertures. On the other hand for the wire mesh, the fibres crossed along the two perpendicular directions of the wires.
SCR performance
The SCR tests were performed in a comparative fashion on self-standing fibres arranged randomly and with preferential alignment. Low amount of catalyst 20 mg at the steady flow of 6 L/h was tested in dry conditions to avoid uncertainties in the measure (see D2.2. for details). Due to the geometry of the SCR reactor used for the lab scale analysis, only fibres laying perpendicular to the flow could be tested. SCR characterization of the fibres with preferential orientation parallel to the flow direction is in fact only possible where the fibres were supported on a substrate. Moreover, due to the reduced height of the hot zone in the reactor, the self-standing fibres layers could not be handled in the quartz tube in a perpendicular position without crashing them. On the other hand, the lab-scale reactor geometry did not allow an analysis of the supported configurations and fibres with alignment parallel to the gas flow was not feasible at the lab scale.
The data shows that both randomly oriented fibres and aligned fibres by fast rotational speed at the drum collector have SCR performance comparable to the reference and largely above the 80% at an operative temperature above 300 °C. These results confirm the ones previously reported in D2.1 and D2.2 and consolidate the principle that the nanofibres are comparable with the wash-coating catalytic layer in the state of the art SCR. The other hand, the sample deposited on the metallic mesh with typical NOx conversion rates above 40%.
This kind of sample has microstructural features with well-packed aligned fibres and large apertures which replicate the shape of the supporting mesh. Since composition and packing of the fibres is the same for all the samples, the presence of the aperture was pointed as possible cause of lack of conversion in the patterned sample. This is also possible considering that large aperture are low resistance paths for the gas through the sample which decrease the actual residence time in the reactor. This factor is also plausible considering that, at the lab-scale SCR, the reactive bed sample has a thickness (hundreds of microns of the deposited fibres) that is very low compared both to the area of the section of the reactor (12 mm) and the actual height of the reactive zone (2 mm). On the other hand, such feature may be beneficial in a real application, where the pressure drop through the SCR has to be minimized.
SCR LAB SCALE REACTOR ASSEMBLY
A small scale reactor made of TiO2-V2O5-WO3 nanofibres deposited on metallic mesh was assembled with the purpose of testing oriented and random fibres at the catalytic level in a reactor-like configuration. A previously mentioned, a small lab-scale reactor has been implemented with the purpose of testing the SCR performance of fibres with different orientation but also to support the other activities in the project dealing with supporting the fibre and designing the final reactor prototype. As a result, the designed reactor was not suitable for conversion and several issues were observed both at the reactor SCR test and at the reactor design levels, which are herein presented.
Concerning the test, the use of a large a canning in the quartz tube was not suitable. At least two major issues were identified along the several tests carried out on the reactors. Firstly, the gap between the quartz wall and the aluminium tube was difficult to seal and the different thermal expansion during the test was opening new possible leaks path at the gas flow. Secondly, the temperature in the distribution in the reactor was not homogeneous due the small hot zone of the tubular furnace in use at the lab-scale SCR setup.
Concerning the reactor design, two major issues:
1. Shrinkage of the fibres on the deposited substrate, as anticipated in D2.1 the shrinkage process from the deposition to the calcination steps is very large (around 60 % in volume depending on the composition of the starting solution).
2. Poor adherence of the fibres on the mesh. Thick layers above 10 µm of fibres deposited on the mesh tend to delaminate. Since fibres have poor mechanical resistance and are very lights, unsupported fibre can easily leave reactors flying with under the stream of gases. On the other hand, thin depositions below 10 µm adhered to the substrate. However the amount of fibres, and thus of the catalytic layer on the mesh, is very low and the residence time probably too low to efficiently convert NOx.
DEPOSITION ON METALLIC MESH SUPPORT
Due to the poor mechanical resistance of the ceramic nanofibres, a substrate to be used as mechanical support was selected by the consortium. The choice was especially oriented toward stainless steel mesh because of the low cost and large availability. The critical factors in the use of the metallic support are:
1. Thickness and coverage of the deposition on the substrate
2. Adhesion of the fibres on the support
These two factors can also result correlated by the fact that the layer deposition influence the critical stress that can lead to delamination. Other factors which lead to delamination are related to the corrosion of the support, such as:
- Thickness and coverage of the deposited layer;
- Adherence, corrosion and layer delamination;
- Self-standing material.
Despite the high performance of the nanofibres developed in WP2, a support is needed to operate the SCR catalysts. The deposition of the fibres is however complicated by the large shrinkage of the as synthesized material during the calcination. This is due to the large quantities of solvent, co-solvent and additives necessary to stabilize and spun the solution. A significant reduction of the shrinkage is thus difficult to achieve with the chemical methods established in the project. On the other hand, the calcination of the deposited fibres directly on the support can easily lead to delamination and loss of covered area, impairing the actual activity of the SCR reaction. Experimental evidenced indicate that lack of deposited fibres at the metallic meshes selected for the project can create preferential open path at the SCR reactor with very limited SCR activity. The chemical composition of the substrate and corrosive effects has to be considered to ensure a proper adhesion of the fibres on the substrate.
SELF-STANDING FIBRES
As discussed, the mechanical strength of the fibres is low and for these reason these have been used on different substrates. However, the mechanical fragility of the fibre relates to the critical strain of the material. For 1D material such nanofibres, bending can easily occur unless the material is not constrained in a fixed position. Fixing the fibre on a mechanical support can indeed avoid the failure. Another solution that can be thus considered is thick layers on several mm or cm. When the thickness of the deposition becomes large the fibres become self-sustaining and the critical strain can be avoided.
GENERAL CONCLUSIONS IN WP2
As general conclusion of the R&D activities in WP2, we have shown that TiO2-V-W nanofibres by electrospinning method are suitable for SCR applications. The material shows suitable conversion and catalytic properties that are equal or superior to the commercial sample. This is with the advantage that the materials is directly formed in the nanofibrous morphology, which is in principle the best morphology for gas treatment because it present only open and interconnected porosity.
However, although the high potential, the integration of the material in a reactor is still open due to the limitation in the processing methodology and mechanical performance of the thin deposition.
The conclusive remarks are:
1. A robust method for the synthesis of SCR Ti-V-W nanofibres has been developed and optimized in terms of starting precursors and process parameters.
2. Process parameter can influence the final morphology and affect the SCR properties.
3. Stability of the starting solution can be optimized and tuned depending on the electrospinning method, equipment in use and storage conditions.
4. A fine characterization of the chemical, structural and microstructural features of the BLUESHIP nanofibres indicate that, since the fibre present high NOx conversion, the composition of the catalyst can be tuned, e.g. by reducing the amount of W. This is the most costly component among the precursors used in the BLUESHIP methodology.
5. Large shrinkage of the fibre at the calcination step represents a critical limitation for the fabrication of the reactor. The contraction of the deposited fibres is mostly associated to the chemistry of the starting solution, which present limited degrees of changes. Large shrinkage above 60 vol. % occurs also on the deposited material and planar constrain to avoid delamination is effective only for thin deposition below 1-2 microns.
Self-standing thick mads in mm range present enhanced mechanical properties and it can represent a solution for the use of the material in the reactor. However, further development for the design and integration in the reactor would be needed.
--------- WP3 - MODELLING AND DESIGN OF ELECTROSPUN SRC (LABOR) ---------
The work conducted in this WP was related to simulate the fluid-dynamic behaviour and of the kinetics of the reaction inside the reactor, by means of computer-aided design techniques and models, identify the layout, dimensioning and design of the SCR for the target application specified in WP1. To achieve the optimization of the reactor design the following steps were followed:
- fluid-dynamic tests and a study of characterization of cell geometry were conducted on different rolled filters, selected in T3.1 as solution to implement the catalytic support for the SCR: a theoretical function was obtained to calculate the geometrical characteristics of the cells by fitting experimental measures, a method for calculation of the equivalent diameter was derived; a method for the calculation of the permeability of the filters from the geometrical characteristics was obtained through parametric calculation;
- the catalytic filters and the SCR were dimensioned to meet the requirements specified for the target application specified in WP1;
- simulations were carried out to verify the pressure drop, gas velocity and the yield of reaction inside the dimensioned reactor, by means of computer-aided design techniques.
MODELLING OF THE FLUID-DYNAMICS AND THE CHEMICAL KINETICS
The study of the solutions for the implementation of catalytic modules to be used in SCR reactor led to the selection of rolled filters as support for the deposition of the Electrospun fibres. The catalytic support selected for BLUESHIP SCR modules has a cylindrical geometry and is composed of a series of cells, in which the gas flows. The Electrospun catalyst is deposed as a thin layer onto the surface of the support, being in contact with the flow in the cells. These modules, known in commercial applications as rolled filters, have considerable advantages due to their high specific surface area and the possibility of deposition of the catalyst through a continuous deposition, easily scalable for industrial application. In addition, the pressure drop in each module can be controlled by varying the density of cells, usually identified by the parameter cells per square inch (CPSI) in commercial products.
Under this task, Labor has developed three models of the preliminary dimensioning and verification of fluid-dynamics behaviour of the BLUESHIP SCR:
• A simplified model for the preliminary sizing of the reactor based on rolled filter modules configuration, implemented using spreadsheets on MS excel. This model allows to calculate, for specified operating conditions and given space velocity (or residence time) which depend on the required degree of conversion: the volume of the reactor, then the volume of each single module and the optimal CPSI (Cell per square inch) of the rolled filter used as support for the catalyst, to have a comparable surface area with presently applied honeycomb catalyst structure.
• A geometrical optimization model implemented in MS Excel, which allows to calculate, for the given configuration and given permeability of the filter, the pressure drop in the reactor, and optimize the aspect ratio of the duct according to the value of pressure drops permissible. In this optimization phase, the variables to optimize are: the angle of the divergent, the diameter of the duct and the length of the modules.
• A CFD model implemented in OpenFOAM environment, used to simulate the fluid-dynamic behavior of the gas inside the reactor and the chemical conversion. The set of solutions defined with the simplified models will be simulated with the CFD model to validate the behavior at a more detailed scale.
To study the influence of the cell density of rolled filter on the permeability of the filters, which represents the ability to be traversed by the fluid and is a key factor in the CFD modelling, a test bench was implemented in this task for the experimental evaluation of the pressure drop on rolled filters. Results of preliminary tests on rolled filters were compared with a theoretical evaluation of the pressure drop for different cell density. In the next task further tests will be carried to correlate the experimental and the theoretical evaluations.
As a reference, first dimensioning of the SCR reactor was carried out. The volume of SCR is constrained by the residence time of the flue gas in the reactor, in order to have the desired conversion of NOx (τ = 0.18 s). This, for the volume to be treated means a reactor volume of 1.5 m3, which was dimensioned with 100 cm diameter and 150 cm height, consisting of 3 modules each with height 50 cm. When adding the divergent, the stagnation areas and the convergent, a total length of about 4.5 m was achieved.
The preliminary design procedure applied through the models implemented follow the steps below:
• Input data (kinetic data, volumetric flow ratio, reactor type, catalyst support solution, operating conditions, conversion degree);
• Simplified model for the preliminary sizing (set of optimal configuration – space velocity, volume of reactor, CPSI of the catalytic support, permeability of the support etc.);
• Simplified model for geometrical optimization and pressure drop calculation (angle of the divergent, diameter of the duct and the length of the modules);
• CFD simulation (verification of the pressure drop and chemical conversion of the reactor).
For what concerns the study of the fluid-dynamic behavior, needed for the evaluation of the pressure drop in the SCR system, first a theoretical characterization of the total pressure drop in the SCR system was carried out, in order to highlight the parameters that affect it. To calculate the load losses starting from the previously reported theoretical study, a simplified model developed in MS Excel spreadsheet was used as first approximation. The effect of variation of geometric parameters (divergent and convergent angles and reactor length) on pressure drop was evaluated.
PARAMETRIC STUDY AND DESIGN OF THE SCR UNIT
The task concerns the use of the simulation model, developed in the previous Task 3.1 for performing a geometrical optimization of the SCR, in order to find the most suitable solution among two/three different options as a trade-off between simplicity, compactness and resistance time for the efficiency of the catalytic reaction in presence of catalyst.
To achieve optimization of the reactor design the following steps were followed in this task:
• From preliminary tests conducted on the rolled filters selected in D3.1 a study of characterization of cell geometry was conducted;
• A theoretical function was obtained to calculate the geometrical characteristics of the cells by fitting experimental measures, and a method for calculation of the equivalent diameter was derived;
• The match between experimental and theoretical data for the pressure drop was obtained through parametric calculation, from the geometrical characteristics of the cells according to the flow;
The target of the project is to double the surface area of the filter with equal volume. Once defined the geometry and the number of cells, the filter is dimensioned to achieve the requirements.
The results implemented by LABOR in this task are the following:
simulation models supporting the dimensioning of the reactor and the concept design
definition of reactor and plant design layout with the required control system and dimensioning of the final reactor adopting the rolled filter support as catalytic modules
Models implemented for the dimensioning and verification of fluid-dynamic and kinetic behavior of the BLUESHIP SCR reactor are the following:
1. Model for the geometric characterization of the cells and the calculation of the available surface for rolled filters depending of the number of cell density:
a. Characterization of the geometry of the cells to the filters 300, 600, 900 CPSI;
b. Extrapolation using the calculation model of the passage section and wetted perimeter;
c. Measurements of load loss on the filters for experimental fitting;
d. Fitting of experimental data per cell sizing;
e. Iterative calculation for the optimization of the equivalent diameter.
2. A CFD model implemented in OpenFOAM environment, used to simulate the fluid-dynamic behaviour of the gas inside the reactor and the chemical conversion of the SCR reaction.
DIMENSIONING OF THE BLUESHIP SCR UNIT
The dimensioning of the BLUESHIP reactor for the application identified and specified in D1.2 was carried out starting from the main constraints: conversion, load losses permissible in the reactor, activation temperature of the catalyst, space and weight constraints.
The conversion depends on the chemistry of the reaction and is closely linked to the amount of catalyst per unit volume and the surface area of the support.
The pressure losses depend instead on the input flow rate and the size of the cells of the support. To dimension the reactor we must therefore consider several variables and move in phase space for proper configuration.
To calculate the space velocity, the kinetic data obtained at DTU while making preliminary tests on catalytic activity of material were used as starting point to determine the best operating conditions for achieving optimum efficiency.
Tests at DTU were conducted on 20 mg in a glass reactor of 0.3 cm3. On the base of these conditions, the space velocity was calculated. Once determined the space velocity at lab scale, we calculated the volume of the BLUESHIP SCR reactor for treating the mass flow rate specified in D1.2 using the preliminary model for dimensioning implemented in MS Excel, here reported. The assumed and target values are therefore:
• Volumetric flow rate: 26.658 m3/h
• Rolled filter cell radius = 2 mm
The following assumptions are also made:
• Active surface of the catalyst is equal to the surface of the support onto which it is deposed (no higher surface due to the high specific surface of fibres is considered). Of course the use of fibres will give an active surface factor well above 1 (first estimation considered was 10 m2/m2), increasing the catalytic active surface with the same support surface. This will allow reduction of the cell density with the same reactor volume or improve the conversion with the same volume (or balance of the two).
• The deposition of the catalyst is realized on both faces of the corrugated surface of the rolled filter.
To carry out the geometric dimensioning of the reactor, we set variables specified by the project in D1.2 and we have obtained the equivalent diameter required to comply with the project specifications. By setting the maximum value of allowable pressure loss and the geometric dimensions of the reactor obtained from the preliminary dimensioning reported in D3.1 using the iterative spreadsheet we obtained the equivalent diameter and below wetted perimeter and surface extension of the reactor.
The iterative calculation yielded the following results:
• Hydraulic diameter 4mm
• Reactor diameter 1500 mm
• Reactor module length 500 mm
• Number of modules 3
• Reynolds number 700
• Reactor volume 2,64 m3
• Space velocity 10075 1/h
Once we know the hydraulic diameter we can calculate the cross section of each cell, then the number of cells and the corresponding cell density.
ANALYSIS OF KINETIC BEHAVIOUR OF ES CATALYST
In the BLUESHIP reactor the reaction takes place between two reagents: NOx and NH3 activated by a catalyst. The reagents are in gaseous phase while the solid catalyst is deposited in the form of nanofibres on a support corrugated as described above. The reaction is then a reaction catalysed heterogeneous, in particular the reduction reaction of NOx follows the Langmuir model. At the operating temperature of about 350 ° C the model of adsorption is described by Eley-Rideal. The reaction takes place on the catalyst surface as described by the model.
Reactions on surfaces are reactions in which at least one of the steps of the reaction mechanism is the adsorption of one or more reactants. The mechanisms for these reactions, and the rate equations are of extreme importance for heterogeneous catalysis. The necessary first step in a heterogeneous catalytic reaction involves activation of a reactant molecule by adsorption onto a catalyst surface. The activation step implies that a fairly strong chemical bond is formed with the catalyst surface.
This mode of adsorption is called chemisorption, and it is characterized by an enthalpy change typically greater than 80 kJ mol - J and sometimes greater than 400 kJ mol- J. Since a chemical bond is formed with the catalyst surface, chemisorption is specific in nature, meaning only certain adsorbate-adsorbent combinations are possible. Chemisorption implies that only a single layer, or monolayer, of adsorbed molecules is possible since every adsorbed atom or molecule forms a strong bond with the surface. Once the available surface sites are occupied, no additional molecules can be chemisorbed. In task T3.2 we could calculate the kinetic constant by numerical integration starting from DTU data.
CFD SIMULATIONS RESULTS
According to the theoretical analysis developed in the previous section, we have developed a numerical simulation model in the OpenFOAM environment. The analysis has been conducted on a reactor configuration sketched in D3.2 characterized by:
• a divergent inlet section, characterized by an inlet angle θd = 20°;
• a cylindrical section with constant diameter, containing three SCR modules;
• a convergent outlet section, characterized by an angle of θc= 36,5°.
By simulating different configurations w obtained the following:
• Configuration 1: R1=0.267 m, R2 = 0.75 m, Ld = 1.34 m, θd ≈ 20°, Lc = 0.66 m, , θc ≈ 36.5°, Lm = 0.5 m, LSCR = 2.1 m, Ltot = 4.1 m; S/V=200 1/m;
• Configuration 2: R1=0.267 m, R2 = 0.75 m, Ld = 1.34 m, θd ≈ 20°, Lc = 0.66 m, , θc ≈ 36.5°, Lm = 0.5 m, LSCR = 2.1 m, Ltot = 4.1 m; S/V=400 1/m;
• Configuration 3: R1=0.267 m, R2 = 0.75 m, Ld = 1.34 m, θd ≈ 20°, Lc = 0.66 m, ,θc ≈ 36.5°, Lm = 0.5 m, LSCR = 2.1 m, Ltot = 4.1 m; S/V=600 1/m.
It should be noted that:
1. Reference operating conditions (gases composition, mass flow and temperature) are consistent with the baseline values fixed in previous reports;
2. The main geometrical features of the complete SCR section (R1, R2, θd, θc) have been determined according to the previously performed computations, that aimed at reaching an optimum between pressure losses and the system compactness;
3. The configurations differs in surface-to-volume ratios of the catalytic porous medium (porosity is set to 85% for all cases).
The variables used in the simulation are the following:
• Conversion of NOx
• Gas velocity
• pressure drop in the SCR reactor
The geometrical configuration of the reactor is the same for all configurations and has been analysed the behaviour based on the amount of deposited catalyst (using the S / V ratio) S/V ratio is the ratio between specific surface (defined as surface in contact with gas) and volume of filter.
Results of the simulations ran in this task can be commented as follows:
To achieve very high conversion degrees, increasing the S/V parameter appears to be a more efficient choice compared to the adoption of longer catalytic modules; this is especially true if the S/V increase is obtained with little modification of the overall porous media characteristics (i.e. with small alterations of the viscous and inertial pressure losses);
It should be underlined that the predicted conversion values rely on some simplifying assumptions, such as no ammonia slip and coverage effects, no fouling and a catalyst medium operating at state-of-the art NO conversion performance; this means that, to achieve an overall conversion above 60% for a 1 m long catalytic section, the S/V ratio should be most likely higher than 400; the usage of longer conversion modules is not recommended, unless the viscous and inertial resistance coefficients of the overall structure (support + catalytic medium) can be further reduced compared to the above calculated values.
According to these results, we can notice that 600 S / V ratio is the best case, the required conversion is reached in the middle of the reactor, and then is the case with better performance.
The conclusions of the work carried out in Task 3.2 which was the only ongoing activity under WP3 in the reference period, can be summarized to be:
1. The selected support are rolled filters with a density of cell equal 25 to cells per square inch (CPSI) with an hydraulic diameter of 4 mm, the deposited fibres have a surface area of 40 m2/g and the amount of deposited catalyst is equal to 1g /m2. This means that thanks to the large specific surface of the fibres it is possible to reduce the volume and size of the modules as required in D1.2.
2. The fibres show catalytic activity equal to the reference catalyst and ensure the achievement of the conversion target required.
3. The sizing according to the procedure described product has the following results:
a. Reactor diameter d = 1.5 m height of a single module h = 0.5 m number of modules needed for the required flow rate N = 3 cell density 25 CPSI, thickness of the foil 0,1 mm.
b. Volume of the catalytic modules V =2,64 m3.
c. Specific surface of 961 m2/m3 for each module.
d. Total length of SCR reactor is 4,1 m with divergent angle equal to 20° and length 1,34 m.
e. The convergent angle is equal to 36,5° and the length is 0,66 m.
4. The weight of the dimensioning SCR is 1077 kg for 25 CPSI cell density. The weight of the reference module is of 2200 kg, the weight reduction compared to the state of the art is 50%.
5. The speed inside the modules is less than 10 m/s and the flow is laminar, this ensures the residence time required for the conversion.
6. The catalytic model selected to simulate a kinetic reaction is Eley – Rideal mechanism. Only one reactant is adsorbed on the surface and the kinetic equation is the first order respect NOx.
7. The CFD simulation shows how the conversion varies depending on the particular surface/volume ratio the best performance is obtained for a S/V ratio of 600 1/m. In addition it can be seen how the pressure drop is lower than the required and the temperature is in the range allowable for the reaction.
8. The control system strategy is explained and the process and the instrumentation scheme is show with the logical of control.
--------- WP4 - IMPLEMENTATION OF THE ES-SCR UNIT (NTT) ---------
The objective of WP4 was to define and optimize at pilot scale the production of ceramic nanofibres in order to ensure that the process could be easily transferred at Industrial scale with minor modifications. The most proper device to be used for process scale-up was defined according to technical features of different options that are available within the consortium. The produced nanofibres have been characterized at a preliminary unit was realized. The process and parameter conditions for the processing of the precursors mixture have been optimised and the lasting performance of the solution has been characterised in order to verify the replicability of lab scale production at large scale. The optimal support for the catalytic nanofibre deposition has been defined and the protocol for the production of the photocatalytic filters has been set up.
MAIN RESULTS ACHIEVED IN THE WP
A straightforward way to increase the electrospinning throughput is to use multi-jet spinnerets: the fibre productivity can be simply increased by increasing the jet number. However, multi-jet electrospinning has shown some drawbacks: 1) strong repulsion/interferences among the jets and clogging of the needles. Thus, needless electrospinning represents the most suitable method for manufacturing nanofibres since conical spikes on the surface of a solution layer upon a cylindrical electrode can be generated reducing problem related with cleaning and jets interferences.
Accordingly, production of Titanium Dioxide nanofibres has been scaled-up at NTT by means of needless ELMARCO Electrospinning equipment (NanospiderTM Production Line NS LAB200).
FABRICATION OF FIBRES AND CHARACTERISATION BY LARGE SCALE ELECTROSPINNING APPARATUS
The production of large-scale nanofibres by using Needleless ES apparatus available at NTT has been optimised for the production of catalytic ceramic nanofibres by investigating the effect of single functional components in the process conditions (kind of electrodes – both spinning and collector electrode; Voltage; Distance between the electrodes), under the Task 4.2.
The objective of the Task 4.1 was the identification of the optimal process conditions for the production of ceramic nanofibres with a composition set-up within WP2 at lab-scale by using needleless apparatus. This apparatus has been selected as the most promising and reliable for the production of nanofibrous material at industrial scale.
Process (parameters associated with the design, geometry and operation of the electrospinning apparatus), system (properties associated with the solution used as feedstock) and environmental (atmospheric and other local processing conditions) parameters have been optimized and defined since they are affecting the throughput and the morphology of the resulting nanofibres.
Morphological analyses carried out at optimised conditions show that average diameter is 247 ± 89 nm even if there are some defects (mainly beads) in the nanoweb. Furthermore the addition of water is confirming that the stability of the solution is sufficient to properly run the production in continuous for 2 h.
After 1.5 h – 2.0 h a significant increase of the defect is recorded (from 7-10% of the covered area at the beginning of the production up to 48 – 54% after 2 h) induced by the instability of the Taylor cone. Since the stretching of the nanofibre is induced by the polymer an additional trial with large amount of PVP (1.2 mol/mol) has been carried out to verify if there is a benefit in the morphology of the hybrid nanomaterial.
SEM measurements do not show any benefit in the morphology so it has been decided to keep the recipe reported in Deliverable 4.2 - Characterization of fibres produced with large scale ES equipment - as the most suitable for the large scale production of catalytic nanofibres.
The deposition of catalytic nanofibres onto the surface of metallic supports (AISI stainless steel nets and AISI stainless steel corrugated sheets) has been then carried out in order to characterise ES efficiency for the production of catalytic filter. The optimisation process for the deposition of the nanofibres onto metallic nest have been performed on AISI Stainless steel nets, as well as, AISI Stainless steel sheet, for further details please refer to the Deliverable 4.2. As a result, the scale up for the production of catalytic ceramic nanofibres has been optimised and productivity up to 3.5 g/m2 has been achieved. The geometry and morphology of the supports is not affecting the throughput and morphology of the fibres. The corrugated sheets have been selected as the most suitable support for the production of catalytic filter.
IMPLEMENTATION OF THE ES-SCR UNIT
The prototype of pilot scale BLUESHIP SCR was designed and implemented. The reactor was implemented with specifically realized catalytic filters realized with nanofibers deposed over corrugated /plain metal sheets representing the selected rolled filter configuration. The prototype was equipped with
The pilot prototype was equipped with a specifically designed and realized test bench for data acquisition and control system. Pilot prototype was installed at the testing facilities identified to verify the functionality of the solution for NOx abatement on a automotive diesel engine.
The BLUESHIP ES-SCR pilot scale reactor for ‘proof of concept’ of the layout of reactor defined during the project, was designed, implemented and integrated by LABOR in a test bench for the treatment of exhaust gases of an automotive diesel engine (FIAT Doblò van 1.9 Multijet) at the facilities of the department of the Mechanical Engineering of University of Rome Sapienza, Italy.
The design of the BLUESHIP prototype was carried out taking into account the objectives indicated in the contract, to realize a pilot scale application with size of about 50x50x25 cm and a test bench for its validation, and starting from the concept layout of the BLUESHIP SCR defined in WP3. The catalytic elements provided by NEXT, were defined to resemble the rolled filter concept identified as support solution for the deposition of the electrospun catalytic nanofibers. Each module is in fact constituted by a cube (side = 5 cm) where the support, made of AISI 316, is constituted of layers of corrugated sheets alternated to plain sheets, on which the catalytic fibers were deposited by NEXT on both sides before calcination .
The catalytic modules (5) were assembled and inserted into a specifically designed reactor, which was mounted in by-pass line respect the exhaust gases main line. By means of a manual proportional valve the exhaust gases are conveyed towards the reactor and treated. The NOx value is registered before and after the catalytic reactor to prove its efficacy.
The prototype is equipped with an auxiliary urea line mixed with the exhaust gases before entering the reactor, whose flow is controlled remotely in order to guarantee the proper urea-NOx stoichiometric ratio, and sensor (flow, temperature) to follow the reaction parameters.
A dedicated software in LabVIEW environment was developed to control and manage the test both in manual and automatic mode. The overall layout of the experimental setup built up for the project is shown in the conclusion. The system has been assembled at LABOR’s premises in Rome and then installed at the test bench facilities. Pictures of all the components and of the final assembly installed at the test bench facilities are provided in the document.
The design of the BLUESHIP prototype was carried out taking into account the objectives indicated in the contract, to realize a pilot scale application with size of about 50x50x25 cm and a test bench for its validation, and starting from the concept layout of the BLUESHIP SCR defined in WP3.
Starting from the process and instrumentation scheme, the prototype was assembled. This is constituted by a reactor mounted on a by-pass line of the main exhaust gases line. Before reaching the reactor, the exhaust gas is mixed with urea according the stoichiometric ratio between CH4N2O and the amount of NOx produced by the engine. The manual partition valve allows the operator to regulates the by-pass flow according the flow meter capacity while the temperature is monitored, and if necessary controlled by means of heaters, in order to maintain its value around 350-400°C to favorite the catalytic reaction. After being treated the gases are discharged.
The SCR reactor is constituted by a 5x5cm stainless steel hollow parallelepiped housing, inserted and welded into a stainless steel cylinder. The empty room between the parallelepiped and the cylinder is used to adapt and insert 4 heating elements, series Rotfil-Ultramax, dimensions 12,5 X 300mm, capacity 500W each.
The heaters are thought to compensate the heat dissipation along the piping. The temperature at which the reaction occurs is optimal around 400°C, therefore if the piping between the engine and the reactor is too long there is the possibility that the exhaust gases decrease their temperature too much under such value.
• The catalytic element
The catalytic element was provided by NEXT, to resemble the rolled filter concept, identified as solution for the deposition of the nanofibers for BLUESHIP SCR. It is constituted by a cube (side = 5 cm) where the support, made of AISI 316, is constituted layers of corrugated sheets alternated to plain sheets. Before assembling the cube, the catalytic fibers were deposited on both the corrugated and the flat sheets.
• Urea injection system
In order to inject UREA into the exhaust gases line a flange system have been welded where a 90° bended tube presents on the head inside the flanged tube a thread to screw a 0.30 mm N-oxide stainless steel nozzle with Stainless impeller plate with anti-drip filter. The other extremity of the tube is connected to a volumetric pump, brand Prominent, type beta 4, working pressure 16bar, flow rate 4 L/h.
• Partition Valve and piping optimization
The valve is a butterfly type valve where the handle was modified and a 90° goniometer was integrated to regulate the opening of the valve from 0°, totally close, to 90°, totally open. In order to integrate the parts and elements of the prototype, it was necessary to optimize the piping, according also the room available at the installation site where the prototype is mounted.
• The software
In the following the description of the dedicated software interface developed to interact between the end user and the prototype is provided. The software, developed in LabVIEW environment, provides all the function to control and manage the test bench prototype. The software allows the operator to perform the following actions:
- Set the parameters of process (RPM: engine regime, TI – ENG: engine temperature, FI – ENG: exhaust gases temperature, Deg [90]: V01 manual regulation degrees, Ppm in: NOx in parts per million without catalysis, Ppm out: NOx in parts per million after catalysis, Set point: temperature of the reaction, Stoichiometric ratio: explicit for the UREA flow),
- Start the measure in manual mode or automatic mode,
- Log the data of process.
--------- WP5 - TESTS AND TECHNOLOGY VALIDATION (AKRETIA) ---------
The objectives of WP5 were to perform the tests of the pilot reactor on a test bench, to evaluate the scale up of the reactor, to design a complete plant layout for the application into an industrial production, to qualify the process with respect to the economic competiveness, product quality and regulative issues, especially the compliance with TIER III and the eventual position of a new standard for the NOx abatement.
The activities related to this WP have regarded the performance of NOx efficiency tests for the evaluation of the effectiveness of the nanofibrous filter media in the abatement of the NOX by using an apparatus developed by NEXT, in respect of the technical requirements and limitations. NEXT in collaboration with LABOR has designed the final structure of the catalytic filters integrating ceramic nanofibres. Cubic module with 5 cm side including 20 layers of corrugated sheets and 18 layers of flat sheets to be used as spacers.
The module was assembled allocating different layers in the module envelop (realised by using an AISI stainless steel flat sheet) and it featured self-standing properties since no glue or welding of the different layer is foreseen.
TESTING PROTOCOL
The BLUESHIP test session took place at the facilities of the department of the Mechanical Engineering of University of Rome Sapienza, Italy. The BLUESHIP prototype described in D4.3 was installed in the mechanical workshop of the department, equipped whit a test bed integrating a 1.9 Multijet diesel engine of a FIAT Doblò van to which to prototype was connected. The testing protocol consists in the following:
- An engine speed (RPM) is set and the engine is stressed out (work on gear and brakes) to reach the temperature useful for the catalytic reaction (around 350-400°C);
- The initial NOx content is measured along the exhaust gas main stream. This value is inserted as input in the software which manages the measure;
- The measure starts in manual mode or automatic mode;
- The software, according the amount of NOx and the stoichiometric ratio, regulates the flow of urea for the catalytic reaction;
- A portion of the exhaust gases flow is directed toward the ES-SCR reactor by means of the manual partition valve;
- The catalytic reaction occurs inside the reactor;
- The amount of NOx is measured at the end of the by-pass line after the reactor to evaluate the reduction of nitrogen oxides occurred by means of the ES-SCR reactor.
The relative NOx value is registered by means of a NOx probe which provides the reading of the measure in form of a printed receipt where several parameters are reported, CO [%vol], HC [ppm vol], CO2 [%vol], O2 [%vol] and of course NOx [ppm vol]. Before starting the tests of the BLUESHIP SCR, a mapping of the emissions produced by the test engine was carried out. As expected the NOx emissions increase directly with the increasing of the speed of the engine. The control of the engine allows the users to set five different speeds: 800, 1500, 2500, 3500 and 4000 RPM.
TESTING PHASE
As described in the protocol, the first step of the testing phase consist into pushing the engine, until the desired temperature is reached, temperature between 350-400°C. At the beginning of the test the engine speed was set to 2500RPM, and after the engine reached 350°C, the NOx concentration was measured along the exhaust gases main line, reaching a value of about 1496 ppm.
Then the proportional valve was set to 20°, and the exhaust gas flow was directed through the ES-SCR reactor to be treated, and the NOx emission was measured at the end of the reactor. The value of 1495 ppm suggested that no catalytic evidence was present. In order to verify the truthfulness of the result, the test was repeated again also at different engine speeds. Regardless the engine speed or the test conditions, no evidence of catalytic conversion was observed. It was therefore decided to interrupt the test sessions to analyse the inside of the ES-SCR reactor to try to understand why the catalysis is not occurring as expected.
As a result, it was observed a complete detachment of the catalytic nanofibers from the corrugated and flat metal sheets constituting the catalytic elements, which made the ES-SCR reactor useless for further testing, having compromised the integrity of the catalyser and its functioning.
RESULTS OF TESTS
In relation of what emerged from the testing phase, the following assessments were made:
# Just after the calcination process, which is a thermal procedure occurring at temperature of about 500°C, a pronounced detachment of the nanofibers from the metallic support is observed. However, the entity of such loss in weight of deposited nanofibers was not so high to suggest a deactivation of the catalyser. Therefore the decision to use the metallic support in this form and shape was still in charge;
# The catalytic elements were produced by NEXT and delivered to LABOR for integrating them in the BLUESHIP prototype ES-SCR reactor. During the handling of the elements to put them in place inside the reactor, free powder production was still observed;
# The field test session described in the previous paragraph, unfortunately clarified that a thermal process is going to affect heavily the catalytic elements invalidating completely the adhesion between nanofibers and metallic support;
# During the testing phase, in addition to the thermal effect, a mechanical effect has also to be considered. In fact the engine causes a relevant vibration effect during its run, especially at higher engine RPM, that also affects the ES-SCR reactor, contributing to the detachment of the fibres;
# Another detrimental effect is that the detached fibres can be blown away from the reactor by the exhaust gases that go through the ES-SCR reactor and are lost with the discharge of the gases at the vent making the catalytic elements completely useless;
# The poor adhesion between nanofibers and support is due to the large shrinkage of the fibres during the calcination process as well as the different nature of the two constituents. For the latter, since the nanofibers have a ceramic nature while the support is metallic, during the heating process, the thermal expansion of the two materials is different and also during the cooling step they relax in a different way producing stress and strain phenomena that culminate with the wreckage between the materials.
In order to deal with the weaknesses emerged from the test, a new concept for the application of the catalytic fibres was discussed and implemented at lab scale, where a self-standing catalytic solution is pursued without the use of a support for deposition.
FUTURE DEVELOPMENTS
The concept behind the next step of activities is to evolve the application of the catalytic fibres towards a solution where the fibre forms a self-standing assembly of higher mechanical strength than the thin deposited layers. Since the main drawback in the original design stood in the coupling of materials with different properties, in the new solution the nanofibers were packed in to self-standing elements from the ES deposition to the calcination steps. The use of self-standing nanofibers has the following advantages:
1. At the calcination step, the material is free of shrink without the mechanical constrain of the substrate.
2. During operation, the level of porosity is controlled by the morphology of the fibres only. Tailoring on porosity of the nanofibers by orienteering and pattering has been shown in WP2.
3. Thermal mismatch between metallic and ceramic is avoided.
4. Mechanical failure of the fibres, due to the critical bending strain of the individual fibres can be avoided in thick depositions, where the thick elements have sufficient high stiffness to avoid bending on 1-2%, see D2.2 ad refs.
At this purpose two solutions were tested and developed at lab scale: the first step was to synthesize flakes of pure fibres, and the second step was to produce pellets of pure fibres.
By this solution, pellets and flakes can be used directly in the catalytic bed, without any external constrain and thus resist to mechanical stress and vibration. The pellet produced presented resistance to high porosity, around 60-70%, due to the interconnection spaces between the fibres. Stiff pellets can be handled and did not fail after sintering. This concept introduces the following advantages if compared to the previous solution:
# The metallic support is no more used - remarkable reduction in weight (>80%) and dimension of the catalyser (the use of stainless steel was obliged by the temperature to which occurs the catalytic reaction). During the calcination process the 10/11 of the energy was wasted to heat the metal whose role was purely structural and does not add any catalytic feature resulting in a reduction of energy costs.
# The self-standing pellet can be easily modelled - Before the calcination process, due to the presence of the polymeric chains, the flakes of fibres result easy to handle. They can be bended and therefore they can assume any shape according the needs of the application. Also after the calcination process, when the bulk of fibres has been consolidated in form and shape, there is room for further mechanical action, like making holes if needed inside the bulk by means of a drill thanks to the mechanical strength acquired by the bulk.
# The porosity of the pellet - The high porosity of the pellet does not obstruct the exhaust gas passage, therefore the new filter can be designed taking in account that the gas flow can be orthogonal to the filter being able to go through it, while in the previous application the gas flow forced tangential to the fibres due to the presence of the metallic support.
POSSIBLE APPLICATIONS
a) Packed bed solution: a well-known technology for filtration processes is the packed column; the bed can be constituted of different elements in form and shape according the application. The solid bed can be a bulk mass, solution applicable in applications where the tolerable pressure drop induced by the reactor is rather high, and also where the gas flow does not carry particulate or solid matter which would obstruct the bed. In case of exhaust gases it is preferable a solution where the bed is constituted by a bunch of pellets packed randomly, or presenting particular shape like the Rasching rings, or similar.
a) Improved honeycomb filter: to avoid heavy pressure drop values and obstruction issues, the easer way is to carve conducts to lessen the pressure, just like the honeycomb filters for de-NOx applications already do. The solution hypothesized introduces an innovation to the already existing and most used filter tech: the honeycomb filter. At the state of the art, a standard honeycomb filter is made of industrial ceramic by extrusion technology.
CONCLUSIVE REMARKS
The field test session of the BLUESHIP prototype allowed to point out the limit of the reactor layout designed in the project, which consisted of catalytic nanofibers deposited on a metallic support to realize a roll filter catalytic module. Just after the calcination process it was observed a detachment of the nanofibers from the support, effect which was magnified during the test session.
In fact before and after the test, no decrease of the NOx emissions was observed and the further analysis of the catalytic elements confirmed that the different thermal expansion of the ceramic nanofibers and the metallic support, both during the heating and cooling processes, ends with the wreckage of the elements with a huge production of free catalytic powder that is blow away with the exhaust gases flow.
In order to overcome this vulnerability, a new concept for the application of electrospun nanofibers without the use of a support was discussed. The innovation consists of a self-standing structure, where the nanofibers are self-sustaining without the use of any kind of support. This solution, developed at lab scale, offers the advantages of reducing considerably the weight of the catalyzer (>90%) of the catalyzer due to the absence of the metal; removing the support means also the reduction of the dimensions of the catalyzer and also during the calcination process the homogeneous of the catalyzer guarantee an homogenous relaxing process. No support means also a reduction of costs: no minor energy used to heat the metal.
At lab scale a pellet of nanofibers was synthetized. It presents a strong mechanical stability and a huge grade of porosity (around 60-70%) which makes it easy to handle and manufacture in different form (above all before the calcination process where the polymeric chains inside the fibres make them malleable). In this view, two hypotheses of application were considered: a packed bed solution where the replenishment of the bed is constituted of Ranching ring like catalytic elements made of nanofibers; and an improved honeycomb filter solution where the whole filter is made of catalytic fibres where the exhaust is able to go through the walls of the filter.
In order to prove the validity of this new concept, further tests will be carried out by the Consortium out of the timeframe of the BLUESHIP project, by using the prototype developed and the test bed implemented during the project. The work will consist into producing nanofibers disks to be placed inside the ES-SCR reactor, to realize a proof of concept reactor.
TECHNICAL AND ECONOMICAL ASSESSMENT
The tangible results produced during the project to be assessed are the following:
• Optimized synthesis and network patterning of functionalized fibres and production method at industrial scale
• SCR solution and test bench prototype of the BLUESHIP SCR
As a general consideration, the fibres developed have been confirmed to have the following advantages: a) Very high specific surface area of the active material: about 40 m2/g; b) High performance: better than conventional pure catalytic powders; c) Possibility to have textured components with rational, highly intricate, continuous, and open porosity. The use of electrospun fibres functionalized is expected to generate a relevant increase of the exposed active area in the SCR reactor, with subsequent decrease of volume and weight of the SCR unit. Given problems experienced in the deposition of the fibres onto a substrate, the method of synthesis will be pursued to produce self-standing catalytic mats for the application to SCR for both marine and automotive de-NOx. Reduction of the weight and size of the SCR is of paramount importance for ship and other mobile applications, e.g. light and heavy duty diesel engines.
The characteristics of the apparatus for electrospinning for production of large scale, optimized for nanofibrous ceramic catalyst were defined, and tested for the production at pilot scale, to be fully exploited for the production scale-up. The process parameters and operative conditions were optimized to ensure the best production of the nanofibres morphology (no or minor defects). The evaluation of scale up conditions and costs for production at large scale of catalytic nanofibers, through the scaled up industrial method implemented, were included in D5.2 which aims at assessing the industrial feasibility of the production.
A pilot prototype equipped with data acquisition and control system was designed, realized and installed in a specifically realized test bench capable to verify the NOx abatement on an automotive diesel engine. The pilot prototype was equipped with catalytic filters realized with BLUESHIP nanofibers deposed over corrugated /plain metal sheets representing the selected rolled filter configuration.
A model for the optimization of the geometric parameters of the reactor and the simulation of the fluid-dynamic behaviour was developed during the project, as well as calculation tool for the optimization of the exposed surface available for deposition in relation to the cell density of rolled filters. These were used for optimal dimensioning of the BLUESHIP SCR, and can be reused to simulate the behaviour of the SCR realized with self-standing catalytic nanofibers mats once the fluid dynamic behaviour of the solution will be tested and porosity known.
PRODUCTION COSTS
Production costs for the catalytic module was performed both in the case of the metallic supported substrate and the self-standing pellets.
# Metallic supported modules - assumptions
Production costs for 1 g of Catalytic Nanofibers supported on metallic substrate with a surface deposition of 1g/m2 have been computed for production of catalytic rolled filter module, considering the following assumptions:
• Precursors and polymer costs have been considered according to small scale selling price. A reduction at large scale is expected;
• Industrial costs for solvents have been considered according to quotation available from different suppliers in Italy;
• Energy costs in EU28 has been considered;
• Average personnel costs of 12 €/h (average for technician, according to LINARI staff costs). Annual salary gross and production capability has been considered;
• Energy for calcination has been computed by measuring energy consumption from pilot scale production
The analysis led to a total production cost considering CAPEX and OPEX at industrial scale for the rolled filter production of 9.93€/g.
# Self-standing nanofibrous flakes -assumptions
The same study has been carried out for the production of self-standing catalytic nanofibers produced at small scale within the proposal and that will be further investigated at pilot scale in the next months.
The production of 1 g (corresponding to 125 flakes of diameter 2.5 cm and thickness 0.2 mm) has been considered for the production of the self-standing catalyst. The assumptions that have been considered for the deposition of 1 g of nanofiber onto the metallic support are still valid.
Considering the same annual production, around 1,500,000 flakes can be produced per year, considering that the final OPEX and CAPEX costs are around 7.13 €/gr (0.06€ per flake).
FINAL SELLING PRICE
# Metallic supported modules
The final selling price is estimated considering a profit of around 40% (maximum price: 18.00 €/g). According to the final selling price of the catalytic filters, the expected turnover per year (assuming a linear distribution of the filter sales in the year) is estimated up to 216,000 € and a revenue before taxes of around 60,650 € at regime. The following assumptions have been done:
• The production of the first set of filter is starting one month before the sales;
• The payments is expected within 30 days after the sales;
• The annual depreciation costs have allocated at the beginning of the production.
• Total costs for the marketing and facilities costs have been considered around 30% of the total costs
The analysis conducted in T5.2 led to and expected selling price in the range of 15.0- 18.0€ in order to ensure a good profit out of the investment. The analysis is showing that at least 6,300g (corresponding to 2.4 industrial module with a total area of 2,650 m2) of filter must be sold in order to earn profits at the conditions described before.
# Self-standing nanofibrous flakes
As per metallic supported nanofibers, the final selling costs of 1 gr of flakes has been estimated considering an expected profit of 40%, meaning that the final price is expected to be 12.00€/gr (2/3 of the costs of supported material). A final turnover of around 144,000 € with a profit before taxes of 40,500 € is ensured.
The analysis is showing that at least 7,750 gr of flakes (corresponding to 967,000 flakes) must be sold in order to earn the profits calculated in D5.2.
POSITIONING AGAINST BENCHMARK
The average price of the selected honeycomb catalyzer module in large quantities is around 9,000-10,000 €/m3, according the current selling price provided by Emission Partner GmbH. Hence the typical price of the module in terms of exposed area available is around 15€/m2, considering the specific surface area data of the highlighted honeycomb system. When comparing the price estimated for BLUESHIP (> 18€/g or > 18 €/m2) and the price for honeycomb (15.6 – 17.3€/m2), price for unit of exposed area for BLUESHIP is almost the same than conventional module (+4-15%).
According to D4.3 expected catalytic area for nanofibrous catalysts (specific surface area = 961 m2/m3) at optimal condition is expected to be 2540 m2 (-20% compared to honeycomb) the total price for single industrial filter will be around 45,700 €, whilst the costs for the honeycomb reference is 29,700 € (-35%). However, it must be considered that the price could be competitive since:
1. the exposed area available from nanofibers can be considerably higher than honeycomb .
2. conversion efficiency is expected to be 2-3 times higher than the honeycomb benchmark
3. volume is 20% lower than the conventional honeycomb
TECHNICAL SPECIFICATIONS AND CONCLUSIONS
In order to perform a proper technical assessment of the BLUESHIP results, a list of specifications – taken from D1.2 of the project – was used in this task. For each domain of the project (SCR, electrospinning technique and nanofibres production), tables were created in D5.2 with the purpose of assessing the degree of achievement by the BLUESHIP technology. The scientific and technological results achieved in the research project are very promising: synthesis, performance and industrial scale up for production of catalytic nanofibers are beyond initial expectations in terms of catalytic conversion tested at lab scale. The production method to scale up production for an industrial production was implemented and process parameters optimized to ensure the best production of the nanofibres morphology (no or minor defects). The results achieved at present stage confirm that:
1. Ceramic nanofibres can be produced at pilot scale by using a needleless equipment. The process and system parameters have been optimized and no specific constraints have been identified for the scale-up.
2. SCR performance of the optimized NFs are equal or superior to the state-of-the-art wash coating.
3. Optimized morphology and composition can easily lead to NOx conversion above 80% at high gas hour space velocity (GHSV) of 400,000 h-1.
Deposition of nanofibers is realizable and repeatable with deposition rate of 3.6 +/- 0.3 g/m2. On the other hand, problems were encountered with the solution selected as supporting substrate for the deposition of the nanofibers for the production of the catalytic modules, due to detach of the nanofibers from the metallic substrate. This has caused the impossible industrial feasibility for the long-term behaviour of the nanofibers deposition on the metallic substrate.
Poor mechanical performance of the fibres mats can be solved by thick layers and multilayer mats. This alternative solution was pursued in the final stage of the project and realized in lab scale, producing self-standing catalytic flakes and mats. Tests of this solution at the SCR test bench prototype made available during the project are planned right after the end of the project.
--------- WP6 - EXPLOITATION, DISSEMINATION AND TRAINING (LINARI) ---------
Shipping is the backbone of international trade, some 90% of which is carried by sea. European ship-owners control 40% of the world’s merchant fleet and operate shipping services all over the world, including in trades between non EU countries, for instance between the Far East and Latin America.
Projections for this market indicate the volume of seaborne trade is expected to double from 9 billion tons per annum to somewhere between 19 and 24 billion tons by 2030. China will play a key role in 2030 as the emerging maritime superpower in shipping. China will see the largest growth in commercial fleet ownership, rivalling Greece and the rest of the European countries combined. China will become the world’s primary maritime market, leading in seaborne trade, shipbuilding and vertically integrated ownership and ship management.
A recently updated Oxford Economics study revealed the overall contribution of the European shipping industry to the European Union’s GDP at the end of 2012 was around Euro 145 billion. This demonstrates that the whole marine market is a very wide and fast evolving one.
The marine market, as a general consideration, holds the following features:
- It is a huge and extremely conservative market,
- It proves highly dependent on oil prices/fuel consumption volumes,
- It is subject to an increasing number of EU policies and regulations demanding for more efficient and less polluting solutions,
- Its players are mostly sceptic about renewable energy or new technological solutions’ reliability and efficiency for the application to the shipping segment.
With particular reference to the market of emission control catalysts, data derived from a market study from Frost & Sullivan (2013) show that:
The global emission control catalysts market is expected to reach $6,705.2 million by 2019 growing at a compound annual growth rate (CAGR) of 11.3% from 2012 to 2019;
The mobile emission control catalysts segment is the largest and accounts for 82% of the total market revenue;
The emission control catalysts market for diesel engines is gaining momentum with the emergence of heavy-duty diesel vehicle regulations. Hence, companies are beginning to focus on diesel engines to gain a competitive position in the market;
SCR, originally designed for stationary applications such as power plants, marine applications, and other stationary diesel engines, has gained momentum and is now being deployed even in light and heavy duty diesel engines.
ENVIRONMENTAL AND REGULATIVE ISSUES FOR THE MARITIME SECTOR
Despite the contribution of the shipping industry to environmental pollution proves reduced respect to other transport modalities, the European regulative framework, through the IMO Organization, has drafted several stringent indications that are forcing marine operators to concentrate on more efficient and less polluting solutions.
The global merchant fleet currently consumes approximately 330 million tons of fuel annually, 80-85% of which is residual fuel with high sulphur content, and the remaining are distillate fuels complying with stricter regulations. SOx, NOx and PM are all emissions to air that result from the combustion of marine fuels. These emissions have potentially severe ecosystem impacts and negative health effects on exposed populations. Emissions from the global shipping industry amount to around 1 billion tons a year, accounting for 3% of the world's total greenhouse gas (GHG) emissions and 4% of the EU's total emissions. Without action, these emissions are expected to more than double by 2050. This is not compatible with the internationally agreed goal of keeping global warming below 2°C, which requires worldwide emissions to be at least halved from 1990 levels by 2050.
The Commission's 2011 White Paper on transport suggests that the EU's CO2emissions from maritime transport should be cut by at least 40% of 2005 levels by 2050, and if feasible by 50%. However, international shipping is not covered by the EU's current emissions reduction target. At the same time as publishing a Communication setting out the strategy, the Commission put forward a legislative proposal to establish an EU system for monitoring, reporting and verifying (MRV) emissions from large ships using EU ports. The proposal would create an EU-wide legal framework for collecting and publishing verified annual data on CO2 emissions from all large ships that use EU ports, irrespective of where the ships are registered. Annex VI of the 1997 MARPOL Protocol has fixed the so-called Sulphur Emission Control Areas (SECAs) or Emission Control Areas (ECAs), that is, areas in which stricter controls were established to minimize airborne emissions from ships.
Alternative fuels have been used in the transportation sector in the past. Other fuels that could play a role in the future are Liquefied Petroleum Gas (LPG), Ethanol, Dimethyl Ether (DME), Biogas, Synthetic Fuels, Hydrogen (particularly for use in fuel cells), and Nuclear fuel. All these fuels are virtually Sulphur-free, and can be used for compliance with sulphur content regulations.
As already mentioned, since January 1, 2016 newbuildings intended for operation in the ECAs areas will have to comply with Tier III requirements set in the Marpol Annex VI, 2008. Feasible solutions to meet such requirements include:
- Exhaust gas recirculation (EGR)
- Selective catalytic reactors (SCR)
- Water injection – Humid air motors (HAM)/ Water in fuel /WIF) or
- LNG
Among these, the most promising remains selective catalytic reduction, which also embraces the scope of the BLUESHIP project. Selective catalytic reduction using ammonia as the reducing agent was patented in the United States by the Engelhard Corporation in 1957. Since that time thousands of systems have been installed on terrestrial applications, from power plants to locomotives or automobiles. SCR functions by combining ammonia, typically derived from an aqueous solution of urea, with a catalyst mounted on a ceramic monolith, to reduce NOx forming nitrogen and water. Today, SCR is in use in millions of vehicles and power plants.
Additionally, it is the only technology currently available to achieve compliance with Tier III NOx standards for all applicable engines (state of the art SCR systems are capable to reduce NOx emissions by more than 90% under certain conditions). The maritime sector has had more than two decades of experience with SCR, early implementations being made by MAN B&W and Wärtsilä.
Today, SCR is a relatively mature technology, widely used for NOx control in land-based industry and land-based transportation, and fitted to four-stroke medium-speed engines on a considerable number of ships in service (more than 1250 systems installed on carrier vessels in the past decade).
A number of manufacturing companies have invested in SCR in the 25 years since it was first applied to the marine sector. Currently, companies in Europe, the US and Asia are delivering marine SCR systems capable of meeting current and future NOx reduction requirements.
In the BLUESHIP Final PUDK Deliverable we have reported an analysis of the competitors for the new technology and of the market segmentation.
EXPLOITATION STRATEGY
The unique selling point of the system is to be the first cost effective, highly performing exhaust gas cleaning solution for combined de-SOx and de-NOx abatement available in the shipping industry, also allowing for retrofitting on launched vessels and capable of being even installed on small sized crafts. The technology is expected to have the following advantages in the specific marine application:
a. Very high specific surface area of the active material : about 40 m2/g
b. High performance: better than conventional pure catalytic powders
c. Reduced volume and weight
d. Reduced Total Cost of Ownership for the end user: increase of useful loading area (about 2k€/m2*y)
e. Possibility to have textured components with rational, highly intricate, continuous, and open porosity
The use of electrospun fibres functionalized is expected to generate a relevant increase of the exposed active area in the SCR reactor, with subsequent decrease of volume and weight of the SCR unit on board: reduction of the weight and size of the SCR is of paramount importance for BLUESHIP design and market in the ship and other mobile applications of emission control.
As already pointed out, the approach is to realize a new SCR to effectively meet the future demands of the shipping industry in order to propose the BLUESHIP system first of all to the marine sector, and then to move to other, potentially attractive target markets, also exploring synergies and partnerships with large industrial partners.
It is in fact interesting to evaluate that other possible applications for BLUESHIP SCR could emerge in other mobile emission control applications, e.g. light and heavy duty diesel engines. For instance, heavy-duty diesel engines have higher NOx emissions. SCR technology that achieves 95% NOx reduction is used in these engines. The option to implement further R&D activities to specialize BLUESHIP for this kind of applications is currently under evaluation inside the Consortium.
The results expected in BLUESHIP project are herein summarized and briefly described. BLUESHIP aims to realize an innovative De-NOx Selective Catalytic Reactor (SCR), specifically tailored to the marine shipping industry based on electrospun ceramic fibres, tailored in designed texture modules.
Despite the maritime application has been considered the target one, the potential market for BLUESHIP is really outstanding, due to the huge range of possible applications in several industrial sectors such as automotive, biomass boilers or thermoelectric power plants.
The results from the project are the following:
1. Optimized synthesis and networking patterning of functionalized fibres (PATENT WO 2015/169786 A1);
2. Fluid-dynamic simulation model and optimized design;
3. Optimized production process of functionalized catalytic fibres, and
4. Pilot prototype of the BLUESHIP SCR and results of testing.
The fourth result substantially consists in the integration of all the previous 3 results in the pilot prototype.
Result No. 1 state of development: in regards of this project result, at the end of the second period, the fibres chosen for the Selective Catalysis Reduction (SCR) of NOx, in both disordered and in oriented pattern, their catalytic characterization and performances of the different orientation of the nano-fibres to be used at the SCR, nonetheless their morphological, chemical characterization at lab scale and SCR performances at the material level, have been studied and defined.
Result No. 3. State of development: at the end of the project, all three deliverables have been submitted and the partners defined the characteristics of the needless apparatus for electrospinning for the production of large scale, optimized for nanofibrous ceramic catalyst currently present at the NEXT premises. In addition, the design of the ES-SCR and the physical prototype were implemented.
Results No. 2-4 state of development: At the end of the project reporting, the models and the concept design have been defined, the reactor and plant design layout with the required control system have been produced and the prototype implemented /tested.
The SMEs of the project will be respectively owners of the following foreground:
o AKRETIA, Results no. 1,2 and 4;
o LINARI, Results no. 1 and 3;
o STOGDA, Results no. 2 and 4.
With regards to patenting, a novelty search of the project results has been performed and reported in the D6.1 where the novelty of the project results and the possibility to protect the project results by the means of patenting has been assessed. The strategy for IPR protection has been discussed inside the Consortium.
A final decision on patenting was taken by the SMEs. Specifically, DTU was granted the possibility to patent the results of their research on ceramic nanofibres and to include partial results obtained under WP2 regarding the ceramic nanofibres of interest for the project BLUESHIP. This was done by establishing, in parallel to the filing of the patent, a free-licensing agreement between this RTD performer and the beneficiaries owning Result No.1 on the nanofibres synthesis. The details and the contractual agreements for the license have been reported in D6.3 Filing of patents, which also include the references of the patent and its full text.
The preliminary agreement established among the beneficiaries regarding the exploitation of the results produced in BLUESHIP reports the following indications:
1. LINARI will be the exclusive supplier of the BLUESHIP electrospun fibres and equipment to produce them;
2. AKRETIA will be the exclusive supplier of the BLUESHIP SCR system for maritime applications;
3. STOGDA will get a world-wide license agreement for the design and installation of the BLUESHIP in the naval sector.
The option to apply the results also in other sectors (SCR for automotive and stationary) will also be pursued directly by the SMEs or through licensing (in case of IPR protection). At M24, and according to the results achieved in the project, the SMEs have revised the exploitation strategy as follows, also stated the decisions done regarding patenting in general:
AKRETIA
Result/ Benefit from the project Exclusive supplier of the BLUESHIP SCR system for maritime applications.
LINARI
Result / Benefit from the project Licensee for the exclusive production of the BLUESHIP electrospun ceramic fibres tailored in designed textures module.
STOGDA
Result/ Benefit from the project Design and installation of the BLUESHIP on ships under commercial agreement with the other partners.
As evident from the description of the results and their achievement assessment (D5.1 and D5.2 on the results of field tests and the tech-economical evaluation), we can state that the scientific and technological objectives of the research are to be considered as achieved.
However, results on the SCR performance in reducing NOx and the efficiency of the overall unit still need to be improved in the view of obtaining a more attractive and mature technology, ready to work in a real environment. In fact, since the solution pursued using deposition of fibres on metallic rolled filters resulted not reliable at pilot scale, it was not possible to validate the efficiency of the electrospun SCR.
Plans for future steps required to achieve a more reliable proof of concept were defined, identifying a possible alternative route for the implementation of the BLUESHIP SCR using self-standing catalytic mats realized with the nanofibers, instead of metallic support for deposition. This route was pursued in the final stage of the project and realized in lab scale. Tests of this solution at the SCR test bench prototype made available during the project are planned right after the end of the project with common effort between SMEs and RTDs. After validation at prototype level, engineering and testing at relevant environment level will be pursued by the owners, through funding from potentially interested end users.
DISSEMINATION IN BLUESHIP
An important step for the realization of an effective dissemination plan is the understanding of what to disseminate of a project, how, when and above all to whom. In order to do this, internal discussions were held by the Consortium members to implement a dissemination plan, that is, a well-thought and systematic approach involving the identification of target potential adopters of the technology which is disseminated, and a list of actions – with related actors/partners performing them – considered of support in the transfer of the project outcomes to the selected audience.
In BLUESHIP, a preliminary dissemination plan was created at the beginning of the project; however, this was extended and revised in P2 to ensure continuous exchange of information related to the project results toward the external.
In this sense, dissemination was conceived as a continuously running task within the project.
Full commitment of the partners was put in:
- The interactions with both the scientific and the industrial world, whenever possible;
- The send-out of releases and articles disclosing all the non-confidential information and the details that the SMES decided to share for a proper promotion of the BLUESHIP technology;
- The monitoring of the activities carried out at a Consortium level in the view of refining/ improving the dissemination plan according to the feedback received when disseminating the project.
The main objective of the dissemination in the project is that of presenting the research work carried out in it and to inform any stakeholder about the state of development of the BLUESHIP solution. Additional, but not less important, objectives are related to raising awareness among the end-users about the potential impact of the technology and of describing its main features and advantages respect to state of the art solutions.
There are a number of maritime shipping stakeholders who might be interested in the BLUESHIP project results. These include, but are not limited to the following groups:
- Private sector representatives: ship-owners, shipyards, ship operators and managers, related industries such as shipbuilding or marine equipment;
- Governmental entities, regulators and policy makers in the maritime transport and in the environmental sector;
- Shipping industry (manufacturers);
- NGOs and academic institutions.
Among the several potential stakeholders mentioned above, some key ones have been identified for the BLUESHIP project:
PRIMARY AUDIENCE - Ship-owners, shipyards and designers
SECONDAY AUDIENCE - Maritime sector associations
The project dissemination plan foresaw the following steps:
Stage 1: Preparation phase. In Period 1, the Consortium prepared the way for a more intense communication step by introducing the project and launching its official start, diffusing news about its objectives and expectations. In this phase, dissemination materials were created to support the spreading of the project launch (press release, website, brochure, etc.).
Stage 2: Dissemination for understanding. Once the project has been initially presented and initial curiosity about its results and impact raised, the Consortium planned more targeted activities aiming at ensuring that end users and stakeholders are provided with technical features and details regarding the BLUESHIP technology demonstrating its commercial potential.
The main dissemination activities carried out at a Consortium level were reported in the Final PUDK Deliverable.
Potential Impact:
The unique selling point of the BLUESHIP is to be the first compact, highly performing exhaust gas cleaning solution for de-NOx in the maritime industry, also allowing for retrofitting on vessels and capable of being even installed on small sized crafts, due to reduce volume and weight and consequent reduced Total Cost of Ownership for the end user, due to the increase of useful loading area on vessel. The maritime sector has been considered the target application. However, the potential market for BLUESHIP is really outstanding, due to the huge range of possible applications in several industrial sectors such as automotive, biomass boilers or thermoelectric power plants.
The scientific and technological results achieved in the research project are very promising: synthesis, performance and industrial scale up for production of catalytic nanofibers are beyond initial expectations in terms of catalytic conversion tested at lab scale. The production method to scale up production for an industrial production was implemented and process parameters optimized to ensure the best production of the nanofibres morphology (no or minor defects);
On the other hand, problems were encountered with the solution selected as supporting substrate for the deposition of the nanofibers for the production of the catalytic modules, due to detach of the nanofibers from the metallic substrate. An alternative solution to produce self-standing catalytic mats was pursued in the final stage of the project and realized in lab scale. Tests of this solution at the SCR test bench prototype made available during the project are planned right after the end of the project.
The tangible results of the project, available to the SMEs for exploitation, are the following:
5. Optimized synthesis and networking patterning of functionalized fibres;
6. Optimized production process of functionalized catalytic fibres;
7. Fluid-dynamic simulation model; optimized design and test bench prototype of the BLUESHIP SCR
RESULT 1: Optimized synthesis and network patterning of functionalized fibres
For BLUESHIP project, TiO2-based catalysts for SCR applications were synthesized by a soft-chemistry method to form TiO2nanofibres, functionalized with V2O5 and with both V2O5 and WO3. Titania has been used as support for the catalyst (V2O5 and V2O5-WO3 oxides) and has been synthesized to have high surface area and the anatase phase. The synthetic path elaborated for the SCR consists in the formulation of a Ti-based sol-gel precursor to be used for the electrospinning of the fibres. Pure TiO2fibres can be synthesized and used as catalytic substrate for the functional elements to be added in successive steps. Another procedure adopted in the project includes the preparation of a starting solution added of individual or several the functional elements. In the latter case, the Ti-precursor was functionalized with the catalysts by dissolving the metals (V and V-W) directly into the TiO2 solution. This strategy is considered more valuable than other procedures, e.g. impregnation methods, where the catalysts are added by successive steps on the formed TiO2support. The main advantage of a direct dissolution of the catalysts consists in the fact that the elements result dispersed at the atomic level in the TiO2substrates, forming a highly active surface to the catalytic process. Moreover by this method the functionalized TiO2fibre is produced in a single step reaction at the electrospinning and a single calcination is the second and final step used to complete the fibres synthesis. The result was included in a wider patent application filed by DTU on “OPTIMIZED SYNTHESIS AND NETWORK PATTERNING OF FUNCTIONALIZED FIBRES” (WO 2015/169786 A1). License agreement with the SMEs owners was defined for the use of catalytic fibers for the application of SCR. The fibers have been confirmed to have the following advantages: a) Very high specific surface area of the active material: about 40 m2/g; b) High performance: better than conventional pure catalytic powders; c) Possibility to have textured components with rational, highly intricate, continuous, and open porosity. The method will be pursued by the SMEs to produce self-standing catalytic
RESULT 2: Optimized production process for functional catalytic fibres
The electrospinning solution applied within the project for the production of the nanofibres is a well-known technology. This technique involves the use of a high voltage to charge the surface of a polymer solution (or melt) droplet this to induce the ejection of a liquid jet through a spinneret or a flat surface. Within BLUESHIP project both techniques (needle and needleless technologies) were investigated at pilot scale in order to select the most proper technology to be used for the large scale production of nanofibrous catalyst.
Particular attention was paid to:
- The needle technology (LINARI is producing such a kind of devices) in order to define the most proper design (needle shape and distance) and to
- The geometry of the machineries in order to ensure a proper production of catalyst with diameter in the range 100 – 700 nm.
In fact, another major technical problem for mass production of electrospun fibres is the assembly of spinnerets during electrospinning. A straightforward multi-jet arrangement as in high speed melt spinning cannot be used because adjacent electrical field often interfere with one another. Accordingly, the array of the needles needs to be carefully designed to ensure that the electric filed strength at the tip of each needle is identical in order to produce samples containing uniform fibres.
The characteristics of the needleless apparatus for electrospinning for production of large scale, optimized for nanofibrous ceramic catalyst present at the NEXT premises were defined, and tested for the production at pilot scale, to be fully exploited for the production scale-up. The process parameters and operative conditions were optimized to ensure the best production of the nanofibres morphology (no or minor defects). The evaluation of scale up conditions and costs for production at large scale of catalytic nanofibers were calculated, through the scaled up industrial method implemented, assessing the industrial feasibility of the production.
RESULT 3: Fluid-dynamic simulation model; optimized design and test bench prototype of the BLUESHIP SCR
A model for the optimization of the geometric parameters of the reactor and the simulation of the fluid-dynamic behaviour was developed during the project, as well as calculation tool for the optimization of the exposed surface available for deposition in relation to the cell density of rolled filters. These were used for optimal dimensioning of the BLUESHIP SCR, on the base of which a final layout and design was created allowing for subsequent prototyping of the reactor and its testing at lab scale.
The preliminary layout of the BLUESHIP SCR reactor was conceived as a cylindrical packed bed reactor, with several cylindrical catalytic bed modules put in series, realised through deposition of the catalytic fibres on metallic rolled filter substrates. This solution was chosen to grant mechanical support for the fibres, that are fragile and need mechanical support, and to allow an easily industrially scalable production. Due to the problems of detachment of the fibres from the metallic substrate caused by differential thermal behaviour of fibres and support during calcinations and to the mechanical stresses, this solution was not successful. For this reason an alternative solution to produce self-standing catalytic mats was pursued in the final stage of the project and realized in lab scale. Tests of this solution at the SCR test bench prototype made available during the project are planned right after the end of the project. After validation at prototype level, engineering and testing at relevant environment level will be pursued by the owners, through funding from potentially interested end users (letter of interest from a large ship-owner was already got).
List of Websites:
The aim of the BLUESHIP website is to provide basic information, since the beginning of the project, to the external audience. It gives, in a very immediate way, an overview on the expected technical, operational and strategic objectives and on the relevant events in the addressed market.
The content of the web site is accessible to a general public in order to promote the exploitation of the project and research results. At the same time, the interested companies and the specialist audience will be able to establish contacts through the contact form. The address of the public website for BLUESHIP is the following:
http://www.blueship-fp7.eu/
A dedicated area for the project partners was provided, to be intended as project documentation repository.
Besides the project website, additional information and news on the project can be found at the LinkedIn showcase page at: https://www.linkedin.com/company/blueship-project.