High added value materials from waste tyre gasification residues

Final Report Summary - TYGRE (High added value materials from waste tyre gasification residues)

Executive Summary:
TyGRe is a collaborative project funded under the European Commission's 7th Framework Programme (FP7/2007-2013 call FP7-ENV-2008-1). The project has run from September 2009 to December 2013.
TyGRe project has 9 partners; ENEA (Italy) leads the project as coordinator and the other partners are: ETRA (France), RWTH (Germany), TUBITAK (Turkey), ELASTRADE (Italy), IMEC (Hungary), FEBE (Italy), LIQTECH (Denmark) and SICAV (Italy).
TyGRe focused the attention to the problem of the waste tyres recycling, by promoting their treatment through the development of a thermal process mainly devoted to the production of a high added value ceramic material, the silicon carbide.
The main idea of TyGRe consists in coupling the waste tyre gasification process, which is a thermochemical conversion route for many different kinds of feeding, with a second thermal process, dedicated to the plasma synthesis of silicon carbide, for a more efficient use of the resources.
Such a project defines a recycling scenario that mainly concerns three principal elements (a particular INPUT waste material, an innovative thermal PROCESS and a high added value OUTPUT material).
The overall strategy of the project’s work plan mainly consists of three levels:
• the development of a sustainable recycling process for the waste tyre treatments, with the final construction of a prototype plant for its validation and demonstration;
• the sustainability assessment, in terms of analysis of economic, environmental and social impacts following a life cycle based approach;
• the market requirements analysis and the future perspectives in view of the potential stakeholders, and the diffusion of the results.
The experimental activities have been developed in 9 work packages (WPs); the innovative process has been developed in laboratory and Silicon carbide powders have been successful produced and processed in bench scale (WP1-5). Process parameters for each part were defined and all the units which compose the prototype plant (feedstock preparation, gasification, synthesis, gas treatment and energy production) were planned. Then, the different process modules were constructed and the prototype plant was assembled at ENEA Research Centre. The experimental tests of the process have been carried out.
Results of experimental test were used both to evaluate the performance of the process (yield and quality of SiC from waste tires) and to implement the sustainability assessment via life cycle approach.
Main results and topics achieved during the project were widely discussed in workshops and conferences organized around the Europe and addressed to both expert audiences (research Institutes, industry experts and SMEs) and to a wider audience.
A Web portal allows people to follow the development of the Project and anyone interested in further information can consult it to the following web address: www.tygre.eu
Project Context and Objectives:
The disposal of waste tyres represents a relevant problem within the waste management strategy of the European Community and, despite the attempts of reusing waste tyres in many different ways, a relevant fraction (nearly 13%) is still landfilled.
Pyrolysis and gasification are a promising way for high-efficiency material and energy recovery; nevertheless the experiences on both pilot and industrial scale have shown that without a valuable exploitation of the solid by-product, the whole economic balance of the process is not advantageous and therefore the process is not sustainable.
TyGRe is designed to expand the material outputs of tyre recycling by providing a valuable material with a broad array of applications.
The main idea of TyGRe consists in redirecting the gasification process towards the material recycling, by coupling a second thermal process, dedicated to the plasma synthesis of silicon carbide, to the preliminary waste tyres gasification.
Basically, the whole process consists of the steps showed in figure 1 in attachment.
The project is aimed at recovering the scrap tyre amount currently destined to landfill (400,000 ton/y), in agreement with the “zero-landfill" target prescribed by the EU Thematic Strategy on the prevention and recycling of waste.
The overall strategy of the project’s work plan mainly consists of three levels:
• the development of a sustainable recycling process for the waste tyre treatments, with the final construction of a prototype plant;
• the sustainability assessment, in terms of analysis of economic, environmental and social impacts following a life cycle based approach;
• the market requirements analysis and the future perspectives in view of the potential stakeholders, and the diffusion of the results.
The set-up of the process has been structured on lab scale experiments, a pilot scale plant build–up and the final pilot scale running; furthermore, to benefit from the feedbacks of the multidisciplinary partnership, the experimental activities have been in close relationship with the life cycle studies.
Table 1 shows the partnership composition of the project.
It’s worth of mentioning the relevant presence, within the consortium, of industrial and private partners (producer, recycler, ceramic powder final user and pyro-carbon producer), whose support, besides providing a valuable database of market information, will give a real projection of the future implementation of the developed process in the market.
From the starting date of the project so far, December 2013, the main achievements have been gained, a prototypal plant has been assembled in an ENEA Research Centre and the proposed process, able to recover matter and energy from end of life materials and then contributing to the natural resource saving, has been tested.
First, the whole process was settled in bench scale: process parameters for each part were defined and all the units (feedstock preparation, gasification, carbothermal reduction, gas treatment and energy production) were planned. Then, the ultimate process scheme and the integrate prototype plant flow-sheet were defined and the different process modules were constructed; the final assembling of the prototype plant was completed and experimental tests of the process have been carried out.
The SiC powder produced in laboratory by TyGRe process was successfully sintered in test manufacts (pellets and disks). The ceramic powder obtained from waste tyres was processed by using different sintering methods at LIQTECH, ENEA and IMEC.
High quality results, comparable with those obtained with commercial level powders, have been achieved.
As planned, additional tests with positive results were made on pyro-carbon provided by SICAV and on the synthesis of ceramic powders different from SiC. In order to improve the powder quality in view of the further sintering, a new purification method of the produced SiC powder was developed. The results demonstrate that TyGRe SiC can be used for industrial purposes.
Considering that the main goal of the project is to provide a sustainable solution for waste tyre recovery by producing high added value ceramics, this remarkable achievement was an important step in the consortium life.
In parallel, the sustainability of the scenario including SiC production from waste tyre has been assessed: the studies of Life Cycle Assessment (LCA), Life Cycle Costing and Social LCA have compared the scenario including the TyGRe technology with a references scenario, where post-use tyres are co-combusted in cement kilns and SiC is produced by Acheson process.
Projections on possible commercial sectors attractive for TyGRe products were made by ETRA, in view of the future market application.
The use of wastes like scrap tyres as secondary raw materials will contribute to save natural resources, such as coke or coal, commonly employed in the industrial synthesis processes (i.e. SiC synthesis). The energy recovery performed by the syngas exploitation contributes to improve the eco-sustainability of the whole process.
In addition to the raw materials cost reduction and to the electric energy production, this research could contribute to the improvement of the European industrial sector of ceramics production.
A broad dissemination of selected results, towards the Scientific Community, the Industry, the Policy makers and the Medias, has been performed.
The project has been developed on waste tyres, a priority waste stream, and has led to obtaining a product, the silicon carbide, successfully tested in the formulation of structural ceramics and membranes. Other applications are under investigation.
Impurities introduced with the starting material required the development of special purification methods to upgrade the product for use in high-level applications. The same process developed can also be applied in the future to other starting materials such as wastes (for example plastics, spent activated carbons, etc.) or biomass (for example rice husks, coconut, etc..) or to produce other ceramics (for example Silicon Nitride). Of course the use of "cleaner" reagents could lead to a final product of better quality or to simplify the purification step.
Due to the relevant SMEs presence within the Consortium, the exploitation strategies are primarily directed, for the time being, to verify the feasibility of the direct exploitation of the project results on behalf of the Consortium, even in collaboration with relevant third parties. for this reason, the Exploitation Board is developing an Exploitation Agreement for the dissemination and the exploitation of the research results to companies outside the consortium, for the development of the industrial and commercial phase.
For additional information, please consult the TyGRe website ( www.tygre.eu )
Project Results:
The TyGRe project has involved activities of different technical nature, and this has resulted in the subdivision into work packages listed in Table 2, each of them headed to a partner with experience in the area.
This section summarizes the main S&T results achieved during the project; they refer to the activities carried out within the following work packages: WP1, WP2, WP3, WP4, WP5, WP6, WP7 and WP8. The main results of the other work packages (WP0 and WP9) are highlighted in section 4.1.4. Further details are reported in the deliverable documents.
Work Package 1 was dedicated to “Gasification and gas cleaning” and the activities were developed within the following 3 tasks:
 Task 1.1 - Selection and analysis of the input material (tyre and silica) and preparation of the feed;
 Task 1.2 - Execution of the experimental tests;
 Task 1.3 - Planning of the component (feeding system, reactor and gas cleaning system).
The preliminary activities of WP1, concerning the preparation of the mixtures to be treated during the process, have been conducted on the initial amount of scrap tyres supplied from ELASTRADE and using three different silica source (glass, sand quartz, olivine). For the preparation, a fluidizing agent has been used (particularly, simple water and organic gels have been tested). Then the mixtures have been characterized in terms of proximate and ultimate analysis.
The tests of pyrolysis and gasification of the mixtures have been conducted in parallel on two different continuous bench scale rotary kilns at ENEA and on laboratory scale bubbling fluidized bed gasifier at TUBITAK MRC operating at the same process parameters. Gasification was carried using air, carbon dioxide or water steam as gasifying agent.
In the first kiln, the materials is loaded in a feeder hopper which is fitted with a mechanical stirrer; during the experiments, the material was continuously fed into the beginning of the alumina reactor by means of a screw-driver device. This device has been mostly used for the carbon dioxide gasification experiments and for the most part of the pyrolysis tests.
In the second kiln, the material was loaded in a feeder hopper which was fitted with a screw feeder operating over the whole length of the equipment, heated zone included. Due to this configuration, the material entered the reactor from the hopper and rolled down the length of the kiln. This device has been mostly used for the steam gasification experiments; in such tests the water is injected into the reactor at controlled rate (thanks to a peristaltic pump) through a series of spatially distributed holes located on the central screw feeder.
In both the configurations, the solid residue was continuously discharged in a tank at the outlet of the reactor while the process gas was headed for the cleaning system; the gaseous stream passed through an ice-jacketed condenser trap that condensed the excess steam (in case of steam gasification experiments) and removed the oil particles from the gaseous products; subsequently, it first passed through a column filled with wool glass (to remove the thin soot formed during the treatment), than it bubbled into a 1 M NaOH solution, which served as a basic scrubber for the acid removal, and finally it entered a water-based bubbling system, which prevented any further charcoal transport.
In the third experimental apparatus, gasification agent was sent through a distributor plate to the reactor. Three different gasification agents were used: carbon dioxide, air and steam. The gasification agent streams were mixed before the gasification agent feeding point. Scrap tire was fed with the help of two screw feeders, positioned one on top of the other. In order to analyze the composition of the product gas, a product gas sampling system was constructed in the set up. The studied parameters were gasification agent type, bed material particle size, gasification agent inlet temperature, CO2 to air ratio, steam to air ratio and steam to fuel ratio and equivalence ratio.
The gases produced were on-line monitored via process gas chromatography; the gas heating value (GHV) was calculated from the composition data. The solid products were characterized in terms of ultimate and proximate analysis and further used as starting materials for the ceramic synthesis.
The different tests have been coded according to the process temperature, to the material treated and to the reactive atmosphere. The whole experimental plan performed at ENEA and TUBITAK laboratories is reported in the deliverable D1-A
With respect to the gas fraction, the principal components (apart from the carrier gas, that is nitrogen or carbon dioxide) detected over the different trials were H2, CH4, CO, CO2, and small quantities of some hydrocarbons, such as ethane, ethylene, and acetylene.
The in-depth study of the trends of the main outputs (gas composition, yields, etc.) versus the process conditions (mainly temperature and reactive atmosphere) has been of utmost importance for the drawing up of the technical specifications and for the choice of the final pilot plant set-up.
As far as the cleaning of the gas, two configurations were tested: “cold” gas cleaning system (ENEA) and “hot” gas cleaning system (TUBITAK MRC). The first one is a classic wet cleaning system of proved efficiency for acid component removal. The second is a sorbent/catalytic system that cleans the gas at high temperature.
Hot gas clean-up studies have been started with hot gas sulfur removal on Turkish dolomite. A series of tests has been carried out to understand the sulfur capture capability of the dolomite. Temperature, gas hour space velocity, gas composition and sulfur load were the parameters, were changed during tests.
For the removal of tar compounds, a commercial steam reforming catalyst has been experimented under catalytic methane steam reforming reaction conditions. Precious metal based catalyst has been used for the experiments. Xylene, toluene, benzene, ethyl benzene and naphthalene were the surrogated compounds for tar in the first trials.
The works on scrubber as a cold gas clean-up tool have been continued by ENEA.
The experimental data have shown that the “hot” gas cleaning system has some limitations and it cannot be used over the entire range of the selected process conditions especially for the sulfur removal with contemporary presence of steam.
Dolomite is effective for bulk sulfur removal with limitation due to the problems related to the syngas composition (steam, CO2); for fine sulfur removal ZnO should be used.
None of the catalysts presented an appreciable activity for total steam reforming of tar compounds but just a selective steam reforming trend.
Finally the solution implemented on the prototype, as a compromise of effectiveness and cost, has been a hybrid of the two systems, using a hot bag filter covered with CaO/activated carbon and further the wet cleaning system.
The steam gasification experiments, together with the main results about the influence of the process parameters on the performance in terms of solid and gas yields and gas composition, are widely described in deliverable D1-A.
Based on the results obtained, the Gasification and Gas Cleaning Units were designed. As far as the technology chosen for the gasification, a rotary kiln was finally selected as reactor, turned to be the most promising processes. This technology allows a good control of char production and its recovery is simple. The fluidized bed technology was rejected because provides several operational problems.
The objective of work package 2 in the TyGRe project was the design and construction of two membrane processes for gas separation. The first gas separation unit has the aim to clean up the argon torch gas stream after the ceramic synthesis; the second one was devoted to grade up the syngas by CO2 removal.
Since process design results for the synthesis gas treatment showed that neither a high purified H2 stream nor a high purified CO2 stream can be realized by a membrane process under the considered process conditions, and in addition to insufficient budget, the second gas separation unit was left.
The process design for a gas permeation unit depends strongly on the feed gas composition. Differing feed gas compositions cause a changed separation performance of the membrane processes and can induce reduced product purities or product recovery rates. Therefore it was essential to fix the boundary conditions for the membrane process before starting the process design. The boundary conditions were fixed based on the overall process calculation by ENEA and TUBITAK.
The most promising materials were selected for module design and the membrane process development started with the determination of the membrane separation performance.
Simulation models were implemented for the different membrane module designs to represent the module separation performance. The simulation models have been used for calculating and optimizing the module configuration and to design a final process design. Finally the prototype plant was built according to the simulation results.
The most applied material for gas separation membranes are polymers. Despite the high number of known polymers and polymer blends only a few gas permeation membranes are commercially available. For the construction of the pilot plant a sufficient membrane area has to be available. Therefrom the selection of potential membrane materials had to be restricted to commercially available membranes. Five different membrane materials have been used for the tests and they are marked from M1 to M5.
The results of single gas tests have given a first information about the potential applicability of the membrane materials for a given separation problem. The tests were executed for all the received materials at three different temperatures and different pressure rates.
Because the mass transfer through the membrane is proportional to the pressure difference for single gases, one average permeance could be calculated for every temperature and every gas.
The selectivities as the quotient of the permeances give information about the separation effect of the material. The experimental results are summarized in deliverable D2-A.
three membranes were chosen for further process design.
For the evaluation of different process designs it has been necessary to implement the different membrane modules in simulation models to represent the module separation performance. The models were designed in Aspen Custom Modeler®. For all the investigated modules the results feature only low deviations between experiment and simulation.
For a first application in the TyGRe pilot plant the membrane separation processes should be simple, easy to maintain and easy to control. In addition it should show acceptable investment costs.

The two simplest membrane processes
 single stage separation with feed gas compression to provide the driving force,
 single stage separation with vacuum at the permeate side to provide the driving force,
have been investigated in a first step.
In membrane separation unit the product (Ar) accumulates on the retentate side of the system. Therefore the desired purity can always be reached by one stage using a sufficient membrane area.
Unfortunately the product losses rise with higher purities. The recovery rate can be raised by multi‐stage process design. The feed gas is compressed to generate the driving force.
For the calculation and comparison of the different membrane process designs and different membrane modules, the different Aspen Custom Modeler© models were installed in Aspen Plus©. Afterwards the complete membrane process was designed and calculated.
The process designs were calculated for membrane modules with the selected membrane materials.
The reachable recovery rates are nearly identical for the two single stage processes. For a CO2 fraction of 2% in the retentate a recovery rate of around 75% can be realized. The treated feed flow rate is ten times higher for the compressor application. For the vacuum application a ten times major membrane area has to be implemented. With the same purity specification of 2% CO2 in the retentate a recovery rate of around 87% can be reached.
A process design of gas separation system was then developed once defined the boundary conditions (composition of gas in input of the gas separation). The new calculation results for the process performance are shown in deliverable D2-B. It is composed by three identical lines are set in parallel. Every line has two membrane modules in series.
WP3 was devoted for:
• Evaluation of the gaseous products formed during the gasification of scrap tyres for energy production;
• Planning and construction of gas conditioning system;
• Planning and construction of the energy production system.
The activities of WP3 were executed in five tasks, hereafter described in detail.
TUBITAK MRC has carried out a draft “chemical process simulation” study. The data supplied by the project partners has been used as a first input to the simulation work. The more realistic process simulation study has been improved upon further availability of the process conditions. The detailed heat integrated cases have been performed using the requirements of selected energy production system. The results of the simulation studies were used to figure out the effect of gas conditioning in terms of process economics and technical requirements of energy production system. Moreover, within the study of WP6, technical discussions have been realized to reach the optimum process lay out and agreed on that the gas conditioning unit would be composed of two subunits. One of these units (Unit I) was to reform the whole process gas by both steam methane reforming and low/high temperature water gas shift reactions. Hydrogen rich gas would make possible, in the future, the use of efficient energy production systems like fuel cells. The other one (Unit II) was to convert carbon monoxide content of the stream coming from thermal plasma reactor via high temperature water gas shift reaction.
After a series of simulation studies and an appropriate process selection, laboratory studies have been executed. A laboratory scale setup has been constructed for the test of Steam Reforming and High/Low Temperature Water Gas Shift (WGS) reactions.
The commercial WGS and steam reforming catalysts have been supplied for the laboratory scale testing.
Operating conditions such as gas hourly space velocity, reaction temperature, inlet steam to CO ratio and inlet steam to CH4 ratio have been investigated and the operation parameters have been optimized.
Thanks to the laboratory studies, steam methane reforming catalyst was able to be chosen between two alternative catalysts available from two different suppliers. For high temperature shift reactions, two different inlet gas compositions were prepared, one of them representing combined streams of gas clean-up and the other representing plasma module outlet. Depending on the obtained outlet gas composition for high temperature shift reaction, additional tests have been carried out on low temperature shift catalyst.
The experimental tests allowed making a design of the gas conditioning unit.
Gas conditioning system consists of two main sub units namely Unit 1 and Unit 2.

Unit 1 and 2 are defined as the followings;
- UNIT 1 – Steam reformer, HTS and LTS units
- UNIT 2 – WGS (HTS) unit
After establishing an appropriate scale up strategy, dimensioning of the gas conditioning units has been accomplished. Sub-components of the designed units have been specified. After procurements were achieved, gas conditioning units (reactors and other sub components) have been constructed and assembled. The detailed specification sheets of these units are reported in detail in deliverable D3-A.
Energy production system studies have been conducted in parallel to the gas conditioning studies. A literature survey and market research on the provisioned energy production systems (EPS) has been completed and reported in “D3-C Technical Specification of the Energy Production Unit”. Microturbine, Gas Engine, Solid Oxide Fuel Cell and Polymer Electrolyte Fuel Cell have been chosen as the options to be evaluated. Technical and economic analysis of the EPS has been carried out. The selection of the EPS in terms of cost, availability and technical conformity has been done. Gas engine has been selected for prototype plant as the best option in terms of technical and economic reasons. A technical specification document for the required gas engine has been produced.
For the integration of Gas Conditioning Unit (GCU) and Energy Production System (EPS), tuning the settings of the control system, definition of the control test procedures and checking all control loops of GCU have been accomplished and reported in the part of “Checking Control Strategy of GCU” of the deliverable report, “D3-D The integration of the gas conditioning unit with the energy production unit”. The additional needs for the integration of GCU to the main control board of the pilot plant have been determined via the communication between the control staff of the WP3 and WP6. According to this study, each unit has a dedicated control system integrated with the control systems of the other units. The control systems of all units are connected to the main control system for power management of the prototype plant.
Since gas engine would work after mixing the gases coming from different sources, in the prototype plant, an integration study of all these units has been conducted firstly by ASPEN HYSYS process simulation software. Different scenarios have been simulated by simulation package in line with the recommendations of the engine suppliers. Five different scenarios have been studied
The results were discussed in the report, “D3-D the integration of the gas conditioning unit with the purchased energy production unit”.
WP4 of the TyGRe project was dedicated to SiC synthesis with the following goals:
 to set up a pilot scale process for the synthesis of silicon carbide;
 to study the synthesis on bench scale;
 to characterize the ceramic powders from tests on bench scale;
 to design the reactor;
 to construct the synthesis section for the prototype arrangement.
The design of thermal plasma reactor and its auxiliary units requires a detailed knowledge on synthesis reaction taking place. For this reason, the synthesis of silicon carbide was studied on a RF thermal plasma system at IMEC laboratories and on a high temperature furnace at ENEA laboratories.
The experimental work was mainly addressed to the production of silicon carbide starting from waste tyre; different feedings and precursors were tested into the reaction.
The process was also applied on commercial carbon-sources selected by SICAV, with the aim to use spent activated carbons, polluted from organics (i.e. hydrocarbons), as alternative carbon-source in the synthesis. In addition to SiC synthesis, the technology was tested for producing other ceramic powders, such as Si3N4, as well. These tests helped us to interpret the synthesis phenomena in a broader context.
Bench scale tests allowed to verify that in the plasma process high SiC conversion rate have been achieved. The formed SiC has low mean particle size of about 200 nm, and it consists of mainly β-SiC.
The yield, defined as the weight ratio of purified SiC to the starting mixture, may be 20-50 % of the theoretical yield in particular experimental set-up.
Carbothermal synthesis of SiC ceramic powders in high temperature furnace gave very attractive results, as regards the yields and selectivity of products. Our tests proved that a residence time of nearly 90 minutes and a temperature not higher than 1650°C are proper conditions of SiC synthesis. The reaction temperature greatly depends on the quality of carbon source. In these conditions ceramic powder of high β-SiC and low α-SiC content can be produced with a yield of 90-95% related to the theoretical yield.
It was found that the properties of the precursors, especially their particle size and purity, are of decisive importance in terms of reaction mechanism and properties of reaction products. The starting reagents should contain as little metal contamination as possible. It is needed to obtain pure SiC products with negligible amount of fibre-like SiC. An acidic-based treatment applied as purification method on the reagents in some tests was effective towards the impurities removal. It is a prerequisite to improve the quality of the SiC produced by synthesis, in view of further applications (i.e. sintering).
Properties of SiC powders and thus the optimum synthesis conditions cannot be established in a proper way without serious consideration of future exploitation; for this reason sintering tests aiming at production of structural ceramic and membranes have been performed in WP5.
A processing method was applied to purify the as-produced SiC powders from unreacted precursors. The optimum parameters of purification were established.
SiC samples from the thermal plasma and the high temperature furnace processes were analyzed for particle size distribution and morphology, chemical surface and phase compositions.
Both the thermal plasma and the high temperature furnace process are suitable to produce advanced SiC materials from waste tyre. Specialty of the experimental SiC powders is the nanosized particles in the thermal plasma case and the fibrous structure in the furnace process.
Thermal plasma technique has been selected for the prototypal scale. By means of the data collected on tests of synthesis of SiC and of results of calculations of the energy requirements, the prototype plant synthesis section has been designed and then constructed. It is composed by units of storage, transportation, milling and mixing of mixtures, together with the plasma reactor and its auxiliary units for the synthesis of SiC.
The purpose of WP5 has been to determine the quality of the Silicon Carbide (SiC) produced from the waste tires in the TyGRe project. The comparison of the SiC samples produced by ENEA and IMEC in WP4 with the commercial SiC powder was conducted (the results of the experimental activities are reported in D5-A)
The subtask 5.1 was targeted to the optimization of the sintering of the TyGRe powder for making the powder more valuable for production, and generally to explore the feasibility of the industrial exploitation of the powders.
Being derived from a waste material, the produced TyGRe powder is different from the commercial powder, and in some way it can be considered like a new material. For these reason many efforts were put on the research and the optimization of the proper sintering methods, which were used for the commercial powder as well, and the results of both the materials were compared.
Different sintering procedures, commercially used, have been experimented:
 the reactive sintering, where the SiC powder (commercial or TyGRe) is mixed with silicon and carbon as sintering-aids;
 the solid-state sintering, where the SiC powder (commercial or TyGRe) is mixed with boron and carbon as sintering-aids;
 the liquid-phase sintering, where the SiC powder (commercial or TyGRe) is mixed with alumina and yttria (as sintering-aids).
A relevant part of the work was the optimization of the sintering procedures (thermal cycles, amount of sintering aids, and so on) for TyGReSiC. Simple shapes (pellets and discs) manufacts have been prepared to test sintering procedures.
In addition to the traditional heating used for the preparation of the test samples, some sintering tests have been performed with a spark plasma sintering (SPS) machine, available at IMEC facility.
Several successfully sintered pellets were produced by all the partners involved, and the used sintering methods were different from facility to facility, depending on the sintering equipment and parameters.
The samples were characterized by SEM analysis (for the visual evaluation of the sintering), EDX (for the identification of the pollution after the sintering) and density measurements (for the identification of the physical properties of the materials).
Another important step was producing manufacts to test the use of ceramic powders for the production of commercial products. For this reason, discs were selected as geometrical form and, considering the core business of LIQTECH, porous materials were produced.
First results demonstrated the attitude of TyGRe SiC to be sintered together with commercial powder. However, the starting materials (i.e. waste tyres) introduce in TyGRESiC impurities, like metals and oxides, that strongly affect the sintering and whose effect must be carefully evaluated.
The impurities in SiC powder play a very important role, causing poor forming and bad sintering.
Special attention was devoted to powder purification, in order to achieve high quality sintering level. The choice of the correct purification method (for the impurity removal) is very important in order to improve the grade of the produced SiC; this fact is relevant especially with common sintering methods (i.e no SPS and hot pressing sintering). On the contrary, successful sintering tests have been performed by SPS using the same TyGReSiC powder. The sintered samples have 98 % t.d. density.
For this reason, a relevant part of the research work was dedicated to find a valid procedure to use TyGRe SiC.
The experimental work has been developed with a twice aim:
 To improve the quality of the produced powder in view of further application (i.e sintering)
 To optimize the sintering thermal cycle.
Tests have been performed treating both the reagents before the synthesis of the raw SiC produced.
A purification method has been developed and patented by ENEA.
Best results have been achieved applying the method on raw SiC produced.
After the purification, the true density of the powder was determined by helium pycnometry; such a parameter was used as indirect control of the purification level of the powder.
The liquid-phase method was selected for sintering; tests on purified powders were performed at ENEA using pressureless and conventional heating for the preparation of the test samples.
Starting from a commercial powder ready-for-sintering (i.e. prepared by the supplier with the required sintering aids), ENEA tested the thermal cycle for liquid phase sintering process.
On the other hand, another commercial powder has been used for SPS tests at IMEC facility.
Successful sintering tests have been performed with both the techniques: pellets and discs sintered reached a 98% t.d. in line with the suppliers technical specification.
Finally, hardness was measured on samples sintered by SPS and pressureless methods. Samples sintered using commercial powders have been used as benchmark. The results on TyGReSiC were completely in line with the expected values.
Then, SiC powder samples synthesized using the prototype plant were used to perform sintering ceramic product tests. The production of pellets were performed ENEA Faenza for insuring optimal sintering. Even in this case purification method developed has been applied and, as performed for bench scale powders, liquid phase sintering method has been applied. The pressureless method has been used for the preparation of the samples.
The “ready-to-press powder” commercial SiC powder was chosen to compare the properties of the TyGReSiC.
Even in this case using the powder produced in pilot scale, the sintering density of TyGReSiC was 98% t.d. analogous to that of the commercial.
Sintered samples were polished and plasma etched. This etching technique is required with liquid phase materials because the grain boundary phase is leachable with the typical chemical etcher useful for silicon carbide based-materials.
In both samples the residual porosity is very low. Sintered TyGRe SiC is composed by finer microstructure than commercial.
Hardness, fracture toughness, elastic modulus and flexural strength were determined: TyGRe SiC powder showed flexural strength comparable to commercial powder and his hardness was completely in compliance with the expected values reported for the commercial powder.
The sintering of TyGRe SiC powder was a success and pellets of pure TyGRe powder were produced, which shows that the powder can be exploited for industrial purpose.
TyGRe SiC powder was also used to produce a two layer membrane starting from a monotube obtained using TyGRe SiC powder as sublimation grains. These filters have been then compared with those produced by commercial SiC powder. This comparison was based on a standard tests and procedures normally used for characterizing ceramic membranes.
Collected results demonstrated that TyGRe SiC produced in pilot scale has shown very promising properties. Especially the actual grain size has made it commercially interesting. The purity of the powder has significantly increased and actual extrusions and membrane coating has been possible to carry out. The substrates produced partly from the TyGRe powder have shown good formability and sintering. Further the purity has increased to an extent were it was possible to control the viscosity of SiC slurry for membrane application. The final test of the actual produced parts are showing very good trends.
In conclusion, the powder produced in the project is comparable to commercial SiC from the Acheson process used to produce structural components and porous components (sintering applications). The TyGReSiC is very interesting due to the small particle size, which is smaller than regular commercial powder.
WP6 mainly covers the second part of the experimental work of the project; after the preliminary execution of the laboratory tests and following the planning and the construction of the different parts of the plant (modules), the final prototype plant have been assembled. However, during the development of the first part of the project it appeared clearly the necessity to collect the different module contributions in a unique process scheme, assessing in a definite way the different equipments and the process conditions.
The selected Research Centre where the assembly has been performed was the ENEA Research Centre of Trisaia in Rotondella (MT) – Italy. First, a platform in durable prefabricated concrete with cable ducts and a roof to cover and protect the prototypal plant from the elements has been constructed.
Once completed the construction of the platform, the operations related to assembly of pilot plant have begun. First, the layout of the prototypal plant has been defined, in order to assure a proper management of the modules during the experimental tests and the material handling incoming and outgoing from the platform.
ENEA has planned the proper connections among the different modules, based on the flowchart of the process and considering that it was necessary to realize auxiliary pipes for assure a more flexibility of experimentation of pilot plant (for example to allow the operation of some modules while the others are switched off) and the drainage of gas in the emergency torch if some problems were to occur during the experimental tests (obstruction of pipes, faulty of modules, etc).
Figure 2 depicts a frontal view of the assembled prototypal plant.
In support of the prototype plant, ENEA has installed some auxiliaries next to the platform. The plant is equipped with a suitable dry saturated steam generator for the production of the main process steam, with a circuit of demineralized water using some auxiliaries already present in the Research Centre, in particular a chiller and with tanks and lines for the process and technical gases: Ar, He, N2, compressed air, LPG. A water supply ring, with demineralizer, cooling tower and pipelines, feeds the steam generator and the heat exchangers.
ENEA has planned the piping for the supply of these technical gases to the modules of the prototypal plant.
Next to the prototypal plant a steam generator has been installed for the production of steam which is employed in the gasification unit by gasification of tires and in the Gas conditioning Unit. The generator produces saturated steam from demineralized water using LPG as fuel gas. LPG is stored in a tank and fed to to the various devices through a suitable pipe line.
Once the construction, assembling and set-up of the designed pilot plant have been realized, experimental tests for the synthesis of silicon carbide (SiC) from waste tires have been performed. The execution of the experimental tests has been carried out under the responsibility of ENEA which has driven the operation with the collaboration of the partners involved in the construction of the different modules (IMEC, RWTH and TÜBITAK).
For the set-up and operational tests of Gas Conditioning and Gas Engine Units, the following integrations and settings have been issued by the joint work of TUBITAK MRC and ENEA:
 Integration of gas conditioning and gas engine units electrically;
 Revision of control program;
 Start-up the control modules and monitoring the data of gas conditioning unit via the user interface;
 Loading the monolithic catalysts to the reactors;
 Introduction the system to the EC experts and project partners;
 Connection of nitrogen line to the super-heated steam generation unit. Verification of nitrogen flow in the steam lines via mass flow meters, FM1 and FM2;
 Connection of instrument air to the relevant pneumatic valves;
 Checking all instruments and by-pass lines;
 Determination of all leakage points on the GCU and fixation by replacing the flange gaskets and further gripping;
 Checking calibration ranges and measurement functions of temperature transmitters;
 Corrections of differential pressure transmitter measurements;
 Installation and commissioning of gas engine.
For the set-up and operational test preparations on Gas Engine (ICE), it was installed on the platform hosting the prototypal plant, connected to the flare, integrated with the other units for fuel feeding. Thereby, the energy production system was made ready to be tested by means of LPG flow. Before the tests with LPG fuel, parallel feed pipelines were established: one for the syngas coming from the process and one for the LPG which was used for these preliminary tests.

Due to the complexity of the whole process, the partners involved agreed it would been necessary to test the proper operation of the different units separately.
First, experimental tests of gasification of tires were carried out, by varying the main process parameters.
Tests of gasification have been carried out and showed results very similar to those obtained in tires gasification carried out within WP1. They are reported in the deliverable D6-C_b.
Concerning the Plasma module, before the execution of the tests of synthesis of SiC some preliminary studies were performed with the aim to understand how the main process parameters adopted in the lab scale tests carried out in the laboratories of IMEC would be scaled up to assure the same performance in terms of SiC yields and purity.
After this preliminary study, several tests of synthesis of SiC has been performed.
During the first tests, it was noticed an excessive entrainment in the gas flow that would have involved several problems if it were sent directly to the gas conditioning: poison of catalyst used in the desulfurizer and of catalysts used in steam reformer and water-gas shift reactors, obstruction of piping and, of course, pollution. This aspect suggested to make some adjustments to prevent this problem and after them, no evidence of entrained particles has been noticed on the gas flow.
Once solved this issue, several attempts have been carried out to verify the synthesis of silicon carbide using different process parameters or different arrangements (radial and axial feeding of precursors, specific energy consumption, central plasma and carrier gases flow rates and so on).
Moreover, different precursor mixtures have been used for the synthesis, which main difference was basically the particle size.
Tests performed shown that particle size was a critical parameter for synthesis; in fact only under a critical value, it was possible to obtain SiC in the products.
Once settled the particle size as prerequisite, ENEA and IMEC focused their attention on the influence of the main process parameters involved on the yield and quality of products: position of probe, direction of feeding (axial or radial), energy supplied, central plasma and carrier gases flow rates.
In each test carried out, samples of collected powder were taken and subjected to analysis in order to evaluate the presence of SiC, in both SiC-α and SiC-β crystal structures.
In deliverable D6-C_b all the experimental data are reported in detail and, as far as the plasma synthesis which represents the most challenging technology in the process proposed, the influence of the main process parameters on the performance of the process is described.
In spite of several tests carried out by varying all the process parameters involved, the SiC yield was not big enough (about 17% of the theoretical value that one can obtain). This suggested to the partners to perform some technical modifications on the plasma system that allowed to increase the SiC yield up to the 70% of the theoretical value. Details of the modifications, together with data of tests carried out after them, are reported in deliverable D6-C_b.
Main objective of this WP has been the life cycle-based sustainability assessment (LCSA) of the TyGRe technology, where:
LCSA = Life Cycle Assessment (LCA) + environmental Life Cycle Costing (eLCC) + Social-LCA (S-LCA)
For assessing the sustainability of the innovative technology proposed in the TyGRe project a reference system for the post-use tyre treatment has been defined, to which to compare tyres gasification. Co-combustion in cement kilns was selected as the reference system since it is presently the commonest end of life (EoL) treatment applied.
First, a preliminary analysis has been carried out regarding the available approaches for the Sustainable Assessment of Technology, and the methodological framework to be adopted in TyGRe. Moreover, general description of the systems (TyGRe technology and post-use tyre incineration in cement kiln), and some preliminary information on SiC market and applications, data on post-consumer tyres management in Europe and data on the recycling of glass packaging in Europe were investigated. As post-consumer white glass is currently recycled to produce glass in a not saturated market and this production presents lower environmental impacts than the production starting from raw materials, the use of waste instead of raw material does not offer environmental advantages under a scenario perspective, so the use of silica quartz was assumed in TyGRe.
LCA supplied the reference framework for the sustainability assessment. The following functions of the systems have been investigated in the comparison: production of SiC; production of electricity; EoL treatment of scrap tyres; production of clinker. As systems can be compared only if functions are the same the comparison between technologies needed the definition of the following two scenarios:
- Innovative scenario, including: EoL tyres collection and granulate production; TyGRe technological system (pilot plant and industrial scale); clinker production by fossil fuels burning;
- Reference scenario, including: EoL tyres collection and scrap tyres production; production of clinker by co-combustion of EoL tyres; production of electricity; production of SiC by Acheson process.
The perspective adopted is that of a decision maker who is interested in evaluating possibilities of development of new markets for high added value materials starting from waste flows, specifically EoL tyres. In agreement with this perspective, the main function is the production of SiC and the functional unit has been defined as 1000 kg of SiC.
The LCA study has been performed on both pilot plant and industrial scale of the TyGRe technology.
Both the scenarios investigated include systems that are highly energy consuming (Acheson process, plasma torch of TyGRe, and cement kilns). To deal with this critical aspect the scale-up of the pilot plant has been focused on optimising the use of energy and reducing net electricity consumption. The changes of layout and scale that were assumed when moving from pilot plant to industrial scale have led the net electricity consumption from 45 kWh to 8 kWh per kg of SiC produced, if a reaction yield of 85% is assumed. The TyGRe pilot plant and the industrial plant are able to treat 20 kg/hour and 1 tonne/hour of tyre granulate, respectively. The inventory data have been obtained from laboratory scale and design data for the pilot plant and from process simulation software and experts’ judgment for the industrial plant. Life cycle inventory data of SiC produced via the Acheson process have been adapted from the silicon carbide dataset of Ecoinvent 2.01. The LCA4AFR tool, developed by the Swiss Federal Institute of Technology to compare different waste management scenarios in energy intensive industries, has been used to produce the inventory data for clinker production.
Parameterised models of both the scenarios investigated have been built in GaBi software, in order to obtain a good flexibility for the evaluation of different TyGRe plant layouts and assumptions, including different yields of SiC production.
The recommended environmental impact categories classified as level I and level II of the ILCD Handbook have been selected for the assessment. Impact assessment results for two different yields of production (85% and 35%) have been produced. The categories related to energy consumption, i.e. fossil abiotic depletion, global warming, acidification, and photochemical oxidation, are the most significant for this case study. The comparison between scenarios at pilot plant scale shows differences up to 20 %, excepting for fresh water and marine eutrophication impact categories, which are strongly affected by the treatment of the TyGRe waste. The comparison between scenarios at industrial scale shows low/negligible differences, depending on the reaction yield, for most impact categories. Higher fresh water eutrophication values of the Reference scenario are due to waste treatments. Higher values of acidification and particulate matter of the Innovative scenario are due to on-site emissions at the TyGRe plant, emissions that could be reduced by using abatement techniques. A sensitivity analysis demonstrated that some impact categories are much affected by the type of waste management assumed in the study and the models used for the inventory. For this reason, further investigation and optimisation ofstrategies for the TyGRe waste management is strongly recommended.
The eLCC study has been performed under the SiC producer perspective. The function of interest is the production of SiC. The production of electricity by gasification of waste tyres saves energy costs. In this case, no comparison of scenarios is necessary, but the focus of the analysis is on the economic sustainability, i.e. affordability, of the TyGRe technology and the comparison with market prices. To assess the economic sustainability at industrial scale, two methods have been applied for scaling-up the TyGRe pilot plant data: a simplified version of the Analogous Model and costs estimation by technical modelling. Main assumptions for scaling-up by analogy are that the industrial producer applying TyGRe and the reference company (in this case study ESD-SIC BV, which produces SiC with Acheson process) compete on the same market; and that unitary cost of materials is constant. In this way costs derived from the pilot plant have been scaled-up in analogy to the structure of the costs resulting from the financial statement of ESD-SIC BV. The results have shown that maintaining the market marginality would require an extra cost of about 1 euro for the TyGRe technology. This confirms that TyGRe-SiC cannot compete on the market of the low-quality applications of SiC, such as the metallurgical, abrasive and refractory ones, but markets offering higher marginality to producers have to be considered. As a second step of the analysis, costs and investments at industrial level have been calculated on the basis of a pilot plant layout adapted to optimise energy consumption and in agreement with a scale-up factor of 50. Three production yields (85%, 35% and 22%) have been assessed. The results have shown that costs of TyGRe-SiC are from 8 to 38 euro/kg, depending on the reaction yield. As prices of SiC for sintering ceramic products vary from 25 to 35 euro/kg, TyGRe-SiC has the potential to compete on this market, provided that the process is optimised, controlled and standardized.
UNEP/SETAC Guidelines for Social Life Cycle Assessment of Products and related Methodological sheets, and further contributions from NEEDS, PROSA and PROSUITE projects have been the reference documents for identifying the relevant social aspects and indicators suitable for the evaluation of the TyGRe technology. Methods and measures proposed by the existing methodological frameworks can only be partly applied to this study, which is characterized by the lack of an implementing and managing company and low level of market penetration of the technology. Starting from these features and considering the scenarios that have to be compared, relevant social aspects for the new technology have been identified on the basis of the physical characteristics of the technology (equipments and systems), the level of maturity of the technologies compared (TyGRe and Acheson), the type of materials in input (supply chain). The following social aspects have been selected: Health&Safety and Professional Development (which affect the stakeholder ‘workers’); Technology Development (which affects the stakeholder Society); Occupational level (which affects Workers and Society); Suppliers relationships (which affects suppliers).
The results of the analysis of registered patents, taken as a proxy indicator for measuring the effect in terms of contribution to Technology development, confirm the innovativeness potential of the TyGRe technology, being at very early stages in its technology lifecycle. Literature and statistical data support the conclusion that, due to the characteristics of the technology, the impact on the workers’ Health&Safety is potentially lower in TyGRe than in Acheson. The higher degree of automation of the TyGRe technology highlights the need for higher skilled workforce from one side, but the expectation of lower occupational levels on the other side. The latter aspect could be significant under the hypothesis of the new technology displacing the mature one, but a deeper analysis would be necessary to consider specific socio-economic contexts and target markets. Finally, distribution of higher added-value along the supply chain, in particular tyre granulate producers, could be anticipated, especially if TyGRe-SiC can reach a high quality degree, but this will depend on company’s specific commercial agreements.
The application of the LCSA framework in TyGRe proved to be challenging for the following main reasons:
- Presently, the framework has been applied mainly to products already on the market;
- So far the debate on the LCSA has been focused on data availability rather than on feasibility and robustness of the framework itself. The application to TyGRe allowed the identification of lights and shadows of the framework, as a contribution to its further development.
The approach proposed and tested to assess the sustainability of a new technology has been discussed in several international conferences giving a contribution to R&D on LCSA.
The exploitation committee was organized with the objective to identify the existing and the potential markets for the products.
A market inquiry was conducted by ETRA. Current SiC market and applications in the EU and abroad were considered. The analysis revealed that the SiC market is a very complex frame.
Considering that the market is in constant evolution, the picture should be updated periodically including new evidences and emerging sectors.
In 2009 the Worldwide production of Silicon Carbide amounted to approximately 1.2 Million tonnes. The Table 3 reports the distribution of the produced silicon carbide among the four principal continents. China is the largest world producer, currently providing approximately 49% of the total production. Further, Chinese production continues to increase.
At the end of 2012 the global SiC capacity highly increased, rising up to 2,500,000 tonnes per years. The 75% of the total is produced in China.

The markets is shared, in a decreasing order by quantities uses, by the following sectors
- Metallurgical Industry 60%
- Abrasive and Ceramics 28%
- Electro-products 12%

The grade of SiC largely varies among these sectors, as well as its price. Clearly, the greater the degree of purity of the SiC, the higher will be its price. SiC having upper grade of purity is employed in Electronics products, while SiC having lower purity is largely used in Refractory and Foundry.
Purity is defined as a percentage or percentage range and with respect to the application e.g.:
 88 – 92 % Metallurgical, Abrasives
 97 – 98 % Ceramics, Refractory
 99 % Electronic devices and other high value added components

and the decreasing order by prices of the material used by the above sectors are Electro-products> Ceramics> Metallurgical Industry.
New applications in the field of ceramic reinforced composites show the improvements of the mechanical properties using nanometre range SiC particles (nano-composites).
Of course, the electronic industry market requires very high quality materials produced by special methods. This market is in constant growth. The electronic market is an emerging sector in constant evolution, very interesting to be considered for the high price of the produced powders.

The Acheson process is the main industrial method to produce SiC. Approximately 49% of the SiC produced worldwide with Acheson process is the lower purity metallurgical grade and 39% is abrasive grade. The remainder is sold on the refractory and specialty markets. Considering that this process is high energy expensive, the Silicon Carbide cost is strongly affected by the energy price.
The greatest costs of SiC production are therefore energy, as well as pollution controls for both emissions to air and water. A fourth element – currency fluctuation, has played an increasingly important role during the past decade. In fact, energy is the driving force in the production of SiC – the cost of which has been the basis for most pricing increases for more than a decade.

The SiC current produced via plasma system could be suitable for ceramic and/or refractory products. As regards the potential uses for SiC ceramics, it was determined that structural components and ceramic membranes could be an appropriate reference product for the output materials. Silicon Carbide membranes can be used for the filtration of a variety of liquids including waters, chemicals, fuels, among others. They are used as an alternative to filters that require cartridges or polymers, etc. SiC membranes are known for the following characteristics: high flux rate, high membrane area per unit volume, lower cost, lower energy consumption, lower manpower and utility for maintenance and cleaning, temperature resistance at 600°C, corrosion and abrasion resistance, excellent strength, environmental safety.

The production of SiC has increased geometrically during the past decades and basically this has been achieved by using Acheson process. The environmental impact has been deeply investigated and supports the presentation of the TyGRe SiC as a sustainable raw material. Besides the good quality of TyGReSiC, the use of end of life tyres as starting material is a good approach in compliance with the principles of recycling society, saving hence natural resources, and it represents a good opportunity for the tyre recyling industry. Newer methods of producing SiC are also being used and they are more environmentally sustainable. So the environmental comparison between traditional produced SiC and TyGReSiC should be updated from time to time in the future.
Considering the rapid growth and the high price of the produced powders, electronic market seems to be a very interesting sector to be considered. However this application requires high purity powders. The impurities enclosed in TyGre SiC, due to the nature of the materials involved in the process, are probably the biggest limitation for this kind of exploitation.
Based on the results collected during the first experimental work, TyGReSiC could be attractive for the abrasive sector and more for ceramics sintering.
In fact, results as good as commercial powders have been obtained with powder produced in bench scale by conventional and SPS sintering. The experimental evidences encourage the use of TyGreSiC in specific application for liquid phase sintering process.
After experimental tests carried out on the prototype plant, SiC powder was produced and used for preparation of samples of membranes and discs. What will be determining for the success of the TyGRe SiC is the purity and small dimension of the grains. Not only the TyGRe SiC could have characteristics not available in the standard SiC. The data achieved by the project encourage further exploration of market opportunities for TyGReSiC.
Potential Impact:
Strategic Impact

The markets for Silicon Carbide (SiC) are broad, global and growing. Research illustrates how, throughout the 20th Century, SiC usage grew and evolved into an essential ingredient for many of the most sought after high-tech, high performance products and applications – from metallurgy to ceramics, as well as abrasives and electronics. As these sectors have grown, manufacturers around the world have sought new material sources.
Nowadays, the main part of SiC is produced by the Acheson process starting from silica sand and low-ash petroleum coke carbon. The process developed by Acheson uses electrical resistance furnaces of rectangular cross section (Liethschmidt, 2000; Guichelaar, 1997). The electric current is fed into the furnace via graphite or carbon electrodes inserted in the end walls. The yield and quality of silicon carbide are seriously affected by impurities in raw materials. The SiC is formed around the hot core in the form of a polycrystalline, compact cylinder. After the current is switched off, the furnace is allowed to cool for several days. Then the side walls are removed, and the excess reaction mixture is carried off. The roll of silicon carbide contains not only the original resistance core, but also graphite formed by decomposition of silicon carbide. When the SiC roll has been isolated and cooled, it is broken down piece by piece and taken for crushing and refining.
The bar charts in Figure 3 show the SiC world production in 2009.
In particular, as far as Europe, that is the market to which the SiC from TyGRe project is looking at, the furnace and processing plant are located as following, together with their capacity net tons (Table 4).
Despite all progresses and the use of energy saving technologies, SiC production remains energy intensive. As pressures increase to reduce CO2 emissions, new ways are being sought to reduce environmental impacts while maintaining consistent, high performance materials and different technologies are investigated.
In this frame, the TyGRe project was aimed at demonstrating the feasibility and sustainability of waste exploitation, by creating high-value-added materials from waste, as a means of reducing reliance upon virgin resource and increasing resource efficiency in the European Union. Specifically, the project relied upon material from post-consumer tyres as a replacement for fossil carbon materials.
Pyrolysis and gasification are promising ways for high-efficiency material and energy recovery; nevertheless the experiences on both pilot and industrial scale have shown that without a valuable exploitation of the solid by-product, the whole economic balance of the process is not advantageous and therefore the process is not sustainable.
TyGRe is designed to expand the material outputs of tyre recycling by providing a valuable material with a broad array of applications.
The main idea of TyGRe consists in coupling the gasification process with a second thermal process, dedicated to the plasma synthesis of silicon carbide, to have a final solid by-product with market perspectives.
TyGRe project contributes to the objective of the EU Thematic Strategy on the prevention and recycling of waste (COM 2005) and to resource efficient flagship initiative (COM 2011a). In particular, by exploiting the recycling possibilities of End of Life (EoL) tyres, the pressure on demand for primary raw materials will be reduced, thus supporting the reuse of valuable materials which would otherwise be wasted. Moreover, this action potentially supports major economic opportunities (business opportunities and new jobs) and boost competitiveness.
This analysis in TyGRe requires a quantitative understanding of the markets upstream (EoL tyres) and downstream (SiC sintering grade for specific applications) of the supply chain of TyGRe and of how direct and indirect changes in supply and demand of the analyzed good or service act in the markets to cause specific changes in demand and supply of other goods and services.
As far as the markets upstream of TyGRe are concerned, the evolution of EoL recovery and arising has been almost steady until 2012. Then the downturn has impacted also on the market of new tyres. In Europe, around 3.3 million tonnes of used tyres were generated annually in 2012. Of this amount approximately 38% has been recycled (material recycling) and an equivalent amount has gone to energy recovery. Even more significant is the trend of the valorization route from 1992 to 2012.
These data illustrate the extensive progress made in post-consumer tyre management and recycling during the past twenty years. It is important to note that in 1992, prior to the emergence of current collection and monitoring systems, + 65% of all reported tyre arising in the then 12 EU States were sent to landfills – only 35% were disposed by other means.
By comparison, in 2011 – 2012, the 27 EU States and Norway valorized approximately 90% of post-consumer tyres – through a combination of reuse and export, retreading, material recycling and energy recovery. Indications are that less than 10% were sent to landfills.
The EU goal of a ‘recycling society’ with a target of zero landfilling has placed huge demand on EU recyclers. They have doubled their efforts to develop and commercialize innovative technologies, applications and products that meet market needs – while reducing dependency upon virgin resources. New technologies are developing and brought to market offering environmentally sound and cost-effective outputs that meet or exceed performance requirements with sustainable substitutes for traditional materials.
This place Europe in a very good position in term of quantities of tyres recycled to produce raw materials and for the quantities recovered altogether. In this scenario the TyGReSiC is a significant example and could be a model for other projects on tyre recycling.
Regarding the market, the applications for Silicon Carbide are in metallurgic Industry, as abrasive or as a high performance ceramics and in Electronic industry for semiconductor applications. New applications in the field of ceramic reinforced composites show the improvements of the mechanical properties using nanometer range SiC particles (nano-composites). Consequently, economical and efficient synthesis routes for nanometer-sized SiC powders are getting more and more important. SiC-based ceramics are considered as a promising material for a number of high-tech applications due to its unique combinations of properties, such as high hardness and strength, chemical and thermal stability, oxidation resistance, etc.
The market is mainly shared by the following sectors:
- Metallurgical Industry (refractory and foundry) 60%
- Abrasive and Ceramics 28%
- Electro-products 12%

In this frame the volume of the market of our interest (SiC powder for technical ceramics and membranes) is estimated to be 8% of the whole. This quantity is growing with the introduction of new products (i.e. submicron and nanometric powders, nanocomposites, etc.).
The grade of SiC largely varies among these sectors, as well as its price. Clearly, the greater the degree of purity of the SiC, the higher will be its price. Figure 5 shows that SiC having upper grade of purity is employed in Electronics products, while SiC having lower purity is largely used in Foundry.
The SiC price may be included in a range between 1 and 5 euros for conventional uses, and it can be more than 5,000 euros for high-tech applications (Table 5). After optimisation of the processes of production and purification, TyGRe is expected to produce a valuable grade of SiC.
As regards the pricing strategy, analysis within the consortium started, aiming at going deeper in the analysis of market forces and needs. Despite its niche dimension, the SiC markets spread all over the world. There are other forces than simply offer/demand that impact on the dynamic of the prices, such as the delays in supply and the stocks dimension. There are recent new investments in facilities to increase the production in certain areas, and the financial crisis has also affected this sector. In this context the development of scenarios for the prices for SiC materials is an exercise that will absorb lots of efforts of the TyGRe consortium in the near future.
The prototype plant allows the significant scale testing of the experimental process. Conceptually, the prototype has a modular definition, where all the sections are streamlined towards the solution of the technical problems normally encountered in similar treatment plant. Furthermore, the combination of the described sections in just one plant represents an integrated approach towards the waste tyre management and it is the fundamental innovation gathered by the project.
However the cost of the technology limits the range of possible applications. Starting from the data collected in prototypal scale, the analysis of the costs at industrial scale for the TyGRe system, performed in WP7, suggested a cut off value of 25 euro/kg as selling price of TyGreSiC. This achievement excludes low price (metallurgical and refractory) applications. Technical ceramics sector is a very promising application for TyGRe SiC. Very good results (sintered density was 98% T.D.) in comparison with commercial powders, have been obtained with powder produced in prototype scale. The mechanical properties have been compared to the commercial SiC.
The measured values of mechanical properties of Tygre SiC, as reported in Table 6, were very close to commercial SiC powder considered as the benchmark, so it can be concluded that TyGRe SiC is suitable for structural application.
In addition, monotubes membranes have been successfully produced by LIQTECH. The membranes have been characterized compared to that produced by commercial powders. Tests demonstrated that the powder could be used as recrystallization powder in the process and TyGRe SiC showed very interesting properties; for this application the powder resulted comparable to the commercial SiC.
In addition the average value of grain size of TyGReSiC was equal to 340 nm or finer, and the particle size distribution is quite narrow. This value is very interesting and candidates the TyGRe SiC for high technology applications (submicron powders applications).
After the results of experimental tests on the TyGRe SiC and the mechanical characterization done in laboratories, and taking into account the expected industrial cost of production, we arrived to the conclusion that the more promising sector for the TyGRe SiC output is the Ceramics’ one.
The key for the success of the TyGRe SiC is the purity and small dimension of the grains. Such features, together with a proper pricing strategy, will be crucial for a future successful marketing strategy.
Further analysis has been developed within WP8 in order to investigate price dynamics and related driving forces behind them. Those aspects will be continuously updated and possibly widened and analyzed more in depth, to serve at best the needs for the exploitation of the project results.
Dissemination of project results
A broad and early dissemination plan is essential to recognize dissemination as being important and significant to the success of the project.
The objective of the dissemination activity is to create the greatest innovation momentum within the targeted research communities and industries throughout Europe and beyond. Therefore, awareness has been created on the one hand to make a wide range of key persons i.e. decision makers, and “awareness multipliers” (from association, industrial partners, technical board experts) sensitive of the potential improvements by TYGRE innovations. On the other hand, these persons provided detailed feedback, so that the scientific-technological strategies could be further optimized.
The participation to dissemination activities and events has been performed taking into account the geographical mapping of the partners’ countries.
All partners have been strongly committed to disseminate the project’s activities and results at local/national level and at European level as well. Discussion and information exchange between involved SMEs, Association representatives , and RTD players have encouraged has been encouraged with dedicated dissemination events, conferences, round tables, and so on in order to better harmonise participants’ efforts.
With this respect the project’s outputs have been disseminated both at a European level, mostly by taking part or organizing relevant events (such as conferences, seminars, brokerage events, workshops, and so on ) also at a national dimension, by participating in focused national events which have been considered during the whole project implementation. In such a manner, a critical mass of interested audience in Europe was more likely to be reached by the consortium as a whole or by single partners acting on behalf of the project. The outcome of reachout activities has been and will be continuously monitored, as we think is key in order to establish technical collaboration, to provide and get inputs for advancing the project results, as well as to raise awareness among the public decision bodies and policy makers in areas of interest for the project.
The dissemination of the project outcomes and activities have been organized to reach the external audience (section “External dissemination”) as well as as to be shared within the project consortium (section “Internal dissemination”).

i) External dissemination
External dissemination has included all those activities which were able to reach the largest number of professionals and experts in the several scientific areas involved in TyGRe project, as well as to outline the project aims and to enhance public awareness of TyGRe project. They included: conferences, workshops, meetings, poster and articles, website.
Workshop: Dissemination events (seminars) dedicated to TyGRe have been organized by the partnership to disseminate project contents; within this frame the project results and the materials produced according to the proposed technology have been presented to make visible the impact of project. The events were addressed to scientific community, industrial players in the fields of interest of the project and decision makers. They are hereafter summarized (in the brackets, the year of the workshop):
1. “Innovation in tyre recycling”, dissemination event at 17th Annual ETRA Conference (2010)
2. Round Table on Tyre Recycling” at ECOMONDO 14th International Trade Fair on Material & Energy Recovery and Sustainable Development on Material & Energy Recovery and Sustainable Development (2010)
3. ECOMONDO 15th International Trade Fair on Material & Energy Recovery and Sustainable Development on Material & Energy Recovery and Sustainable Development (2011)
4. Dissemination event at 20th Annual ETRA Conference (2013)
5. “I recycling - a source of valuable materials“- dissemination event at ECOMONDO 18th International Trade Fair on Material & Energy Recovery and Sustainable Development on Material & Energy Recovery and Sustainable Development (2013)
An external experts, industrial representatives, public decision bodies and policy makers in areas of interest for the project budget were invited to the thematic events. The events have been organized by ETRA and ENEA.
During the workshops held a very interesting exchange of view between project partners and industrial and scientific representatives took place.
This fruitful dialogue effectively contributed to shorten the gap between the consortium and the external players providing new elements on the real demands of the markets involved.
Congress: Similarly, the results achieved during the project have been presented within the frame of the main representative expositions of the involved business line; particularly, project results have been presented in conferences, as listed below (in the brackets, the year of the conferences):
1. Presentation in “Pyrolysis Forum” at 17th Annual ETRA Conference (2010)
2. Presentation in scientific seminars at 4th International Seminar on Society & Materials, SAM4 (2010)
3. Presentation in scientific seminars at 12nd International Conference on Modern Materials and Technologies CIMTEC (2010)
4. Presentation in scientific seminars at 17th SETAC Europe LCA Case Studies Symposium (2011)
5. European Conference on Tyre Recycling (2011)
6. Presentation in "Contemporary Approaches to Rubber goods and Tires Recycling" at International Theoretical and Practical Conference (2011)
7. Presentation in Int. Conf. European Ceram. Society (2011)
8. Presentation in Hungarian Conf. on Material Science (2011)
9. Presentation at International Congress of Membranes and Membrane Processes (2011)
10. Presentation at 8th European Congress of Chemical Engineering (2011)
11. Presentation in “Pyrolysis Forum” at 19th annual ETRA conference (2012)
12. Techno-economic analysis of a membrane supported CO removal process for Argon recovery (2012)
13. Presentation in scientific seminars at 6th SETAC World Congress (2013)
14. Presentation in scientific seminars at XXII IGF congress (2013)
In addition to these conferences, to disseminate TyGRe project to the wide audience, some press release and media briefings have been issued as following:
1. Tyres turned to treasure (http://www.elements-science.co.uk)
2. “Recycling tyres The ultimate retread” in The Economist on line (http://www.economist.com/node/16780047)
3. “TyGRe targets SiC market” in Silicon Carbide & More (www.siliconcarbideandmore.com)
All these events have led to a wide dissemination of the results achieved within the project towards a large audience of professionals and industry experts.
A lot of expressions of interest have been received by TyGRe website (TyGRe mail); contacts with SiC final users or SMEs involved in Tyre management, pyrolysis and SiC production have been collected.
Publications: the data related to the experimental work results have been published on International journals of recognised impact factor, such as (in brackets the number of publications):
- Waste Management (1);
- Powder Technology (1);
- Fuel Processing Technology (2);
- Industrial and Engineering Chemistry Research (2);
- Fuel (1);
- Acta Fracturae (1).
Other papers have been submitted.
Web Portal: a project web site has been created and administrated by ENEA (www.tygre.eu). It provides access to the general public; the site includes also updates on the project developments and linkages to websites related to TyGRe. In addition a collection of documents concerning TyGRe (document repository) like newsletters, events, congress proceedings, scientific communications and presentations is also present.
The web portal (Figure 6) has obtained and is getting good visibility and assiduous consultation, and from its establishment until the end of the project has counted a number of visits over 2000. In addition, the number of newsletters produced was equal to 8 that have been sent to about 100 users.
The website will be kept alive in order to inform third parties outside the project consortium about the advancement in the development of the exploitation plan, about opportunities may arise for collaboration, as well as to get their inputs for better fine tune the exploitation strategy.
Other dissemination tools were the parallel newsletters disseminating TyGRe project (rete italiana LCA, Tyrepress, etc.). TyGRe is also disseminated on line by others multimedia and networking tools dissemination tools and networking websites like innovation seeds catalogue (www.innovationseeds.eu) EcoWeb- from research to realizations ( www.ecoweb.info ) and ENEA webTV (www.enea.it ). An article about TyGRe project was published by the magazine Focus (www.focus.it ). The communication on the project presented during the 19th and 20th annual ETRA Conference.
ii) Internal dissemination
In addition to external dissemination events, a series of activities aimed at the sharing of information within the working group, and then among the various project partners, have been implemented. They include first of all a series of foreseen internal meetings having the aim of focusing the performed activities, sharing of problems encountered and searching for possible solutions. As planned, the following five main internal meetings have been done (Table 7):
Further meetings have been organized, with different purposes, and hereafter listed and described:
 Meeting date performed on June 28th, 2012 at Budapest (Hungary) discussing the purchasing of the Carbothermal reduction Unit, which is considered the most challenging technology involved in this project.
 External regular/foreseen review performed on March 21st, 2013 at ENEA Trisaia Research Centre in Rotondella (Italy). It has been performed at the presence of two external reviewers, experts in technical area involved within the project. In this occasion, besides the appreciations for the work performed in the project, for the solutions found to face the rubs from the partnership and for the results achieved up to now, the reviewers provided a very interesting point of view on technical and commercial aspects of both the performed and ongoing activities, giving valuable remarks and suggestions to be carefully considered during the final development of the project and in the next future.
Web site internal dissemination: The website includes also a private area (Figure 7), with secure access for project participants, used for internal dissemination and project management. In fact documents relevant for the consortium such as consortium agreement, the complete EC-GA, meeting minutes, deliverables and so on, have been uploaded in the dedicated folders.
Moreover, it includes a chat tool (Tygrechat), a communication channel for the consortium members, devoted to sharing information and for the communication among the partners involved in the project; the tool was useful used to have virtual meetings and to discuss scientific issues.

Exploitation of project results

The exploitation strategy of the consortium firstly aims at developing strong coherent plans for commercial exploitation of project results and deriving marketable products from them. Furthermore, the strategy aims at ensuring the delivery of timely market awareness actions, in order to keep potential parties outside the project consortium aware about the advancement in the development of the plan – in particular, maturation of the results, opportunities for collaboration, as well as in getting their inputs for better fine tune the exploitation strategy.
Exploitation strategy includes:
a) Market and business studies to identify market segment, estimate future market potentials and identify critical success factors for respective exploitation plans.
b) Strategy deployment: action plan for fostering win-win situations among research and business sectors forming virtual alliances and enterprises in order to collaborating in developing products for specific target application, thus reaching a concerted strong impact on the market.
In order to ensure the development of a satisfactory plan for the management of knowledge, intellectual property and other innovation-related activities, we have adopted the following actions:
 A specific Work Package (WP8) mostly dedicated to these activities has been included in the project work program.
 An Exploitation Board has been established.
Due to the relevant SMEs presence within the Consortium (LIQTECH, ELASTRADE, FEBE and SICAV), the exploitation strategies have been primary focused on direct exploitation by the consortium, in collaboration with outside partners. The Exploitation Board is developing an Exploitation Agreement for the dissemination and exploitation of all the results of the research.
Such an agreement foresees a gradual involvement of Companies outside the consortium after an initial period, aimed at the development of the industrial and commercial phase.
The involvement of outside Companies is also foreseen, in a more immediate way, for the exploitation of results which fall outside the markets/applications identified by the Exploitation board. To this aim, the consortium will contact potentially interested private parties for proposing and agreeing on a plan for sharing the know-how and fostering the application of solutions developed within the TyGRe project in all the relevant fields of application.
The objective of this Exploitation Agreement will be to set a framework by which all the project participants can contribute to the achievement of the exploitation and commercialisation goals of the project. Such an agreement comprehensively will cover also the management of intellectual property assets, with clear identification of foreground and background information and related ownership and access rights aspects.
The TyGRe project involves Companies belonging to two complementary sectors: Material supplier (Elastrade, SICAV) and end users (LIQTECH), even if it is to be remarked that the main field of application of our main target product, that is SiC, lies outside the tyre industry. The interest of the former enterprises is to find a valuable route to recycle the waste tyres or the pyrocarbons, while the latter represents the final user of the ceramic materials. The involvement of these two different types of Companies ensures a proper coverage of the SiC value chain, together with the RTD performers.
As regards the first part of the Exploitation strategy (letter (a) above), the consortium intends to continue the work done by the WP8, in order to provide further intelligence for better tune the exploitation plans. The work performed up to know evidenced for TyGRe SiC very good results in structural ceramics market and in ceramic membrane market. In particular, the consortium aims at focusing on 3-5 potential products/applications and concentrates the investigation efforts on those ones. Of course sectors of interest of the consortium partners will be explored firstly. The activity will be complemented with a constant update of the analysis of the market needs, by asking customers’ feedback and opinion in the different sector of applications, as well as involving in the exercise other relevant players from the sectors’ value chain. Such an exercise is crucially important for implementing a concrete action plan to tackle the market needs, by deploying new solutions originated from the TyGRe project. The details on how to proceed on the matter will be discussed in the next months within the project partners.
As regards the section (b) of the Exploitation strategy, TyGRe partners have already identified the key foreground developed within the project (see section of the Report “Use and dissemination of foreground”), coupled with the relevant background owned by each participant, and agreed on a medium term granting policy which originates from the consortium agreement provisions. The plan foresees roles and tasks for each partner, according to:

 their capabilities and competences;
 their interests (research, technical and commercial ones);
 the contribution provided, in terms of background and foreground to be further developed /exploited.

In particular:

- ETRA will promote a new eco-compatible disposal route for waste tyre and coherent with the process developed in TyGRe project which foresees the recovery of material. In such a way ETRA will demonstrate the feasibility of the recycling approach, where nothing is landfilled anymore; furthermore it could give feedbacks to the tyre producers world, focusing the attention on the formulation of new generation tyres.
- ELASTRADE, together with SICAV, will find new opportunities for the introduction of their products on the market. Furthermore, SICAV will try to develop the process at industrial level by tuning the process to the treatment of pyrocarbon as well as on spent carbon.
- LIQTECH is interested into the industrial exploitation of the process, based on the demonstrated economic feasibility of the production of high purity silicon carbide.
- FEBE will develop, together with ENEA, a model for assessing different management systems for end-of-life tyre. In particular, the application of LCA, LCC and S-LCA in the TyGRe project allowed the development of an approach to the environmental, economic and social assessment of new technologies in their early stages of development. This approach could support decision making in projects aiming at developing/implementing technologies from TRL (technology readiness level) IV forward.
- RWTH has streamlined a separation system on gas which could be useful for upgrading of treatment plants.
- TUBITAK has gone in depth into the development of combined thermal process for the energy production, holding a leader position in its own country.
- IMEC has improved the exploitation of plasma technology in the field of ceramic synthesis.
- ENEA, besides the acquisition of new competences on thermal treatment, thermal plasma and conversion, had the occasion to promote the exploitation of an own patents.
The evaluation of Potential Impact of TyGRe Project has been possible also with the information collected in the activities performed within the work packages WP0 and WP9. Main results of these WPs have been reported in related deliverables.

List of Websites:
www.tygre.eu

Final Report Summary - TYGRE (High added value materials from waste tyre gasification residues)

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