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The development and scale-up of innovative nanotechnology-based processes into the value chain of the lubricants market

Final Report Summary - ADDNANO (The development and scale-up of innovative nanotechnology-based processes into the value chain of the lubricants market)

Executive Summary:
AddNano project, above all, aimed at demonstrating the performance benefits of lubricant formulations with nanoparticles and where such benefits could be demonstrated, addressed issues that could constitute barriers to full commercial-scale production of these lubricants. The main objective of the AddNano Project has therefore been to overcome the technological barriers relating to the development of large scale market introduction of a new generation of lubricants incorporating nanoparticles in their formulation. To achieve the market introduction of such advanced lubricants of improved properties and performance, in parallel to performance testing at bench and full scale, various processes from particle synthesis and manufacture to dispersion, stabilisation and final formulation have been developed in this project. Other objectives included:
- develop environmentally well-managed production methods that avoid potential for impact on health and release of harmful chemicals into the environment;
- identify and use REACH-compliant raw materials for the synthesis of MoS2 nanoparticles that are suitable for mass production for use in mainstream high-volume lubricants;
- prepare process design methods for dispersion process (scale-up of from lab to industrial scale);
- design and select process equipment for the industrial scale production of lubricants incorporating nanoparticles in their formulation using findings from the project;
- integrate fundamental understanding and applied research focussed on modelling of tribological behaviour of end-user materials to develop lubricants with tailored tribological functions.

Main project achievements c be summarised as follows:
- Several routes to synthesise MoS2 and WS2 were developed and of these two were retained for the rest of the project with potential for four others to be developed further.
- Whilst the ultimate target of the project was to develop one new formulation, two lubricants could be formulated: a crankcase oil for passenger cars and a grease for industrial bearings.
- Full scale manufacture of one of the nanoparticles is currently possible; the manufacture of the other has been scaled up from a few grams to a few kilograms.
- Incorporation, dispersion and final blending processes were evaluated, designed, optimised and scaled up. Cost calculations were also performed to assess the price of the final product.
- Validated numerical models and process design procedures were prepared. These can also be modified further in the future for other applications.
- Consistent product and process characterisation were conducted. Bench scale tribology tests revealed improved performance of newly formulated lubricants. Mechanism of lubrication could be identified. Analyses of contact surfaces and tribofilms were performed.
- HSE studies included the toxicological assessment of synthesised nanoparticles with in-vitro human epithelial cells. A bench scale diesel engine was used for the analysis of emissions. These studies also demonstrated fuel reduction, confirmed by field tests.
- Field tests aimed at assessing the benefits of new formulations under “real life” conditions. For the engine oil, a 20000 km long drive. Oil analysis, engine emissions and fuel economy tests were performed and emissions measured. For the new formulation grease, demonstration activities involved a pump used for the transport of wood pulp in a paper works factory during 1.500 h operation of under variable load. The final prototype was validated by means of the standard FAG bearing tests FE-8 (DIN 51819-2) and FE-9 (DIN 51821-02).
- An end user survey, LCA and RAMS were performed.
- Dissemination activities included two seminars, conference and journal papers, newsletters and press releases, a dedicated project website: http://sites.google.com/site/addnanoeu/home

Project Context and Objectives:
Fluid lubricants are used in almost every field of human technological activity and their purpose is multi-fold: they reduce frictional resistance, protect the engine against wear between contacting surfaces, remove wear debris, reduce heating and contribute to cooling, improve fuel economy and thereby reduce emissions. Lubricants contain several additives in their formulation which include anti-corrosives, anti-oxidants, detergents, dispersing agents and most importantly friction modifiers and anti-wear agents. Nanoparticles have shown indications that they can contribute to friction reduction and enhancing protection against wear and within the scope of the AddNano project, the potential of using nanoparticles in the formulation of lubricants has been explored.
AddNano, “The development and scale up of innovative nanotechnology based processes into the value chain of the lubricants market”, is a Large Collaborative project (Project No 229284). It is funded FP7 NMP-2008-1.2.2- Pilot lines to introduce nanotechnology based processes into the value chain of existing industries.
One of the motivations of this project has been to investigate the prospect of using nanoparticles as anti-friction, anti-wear agents to replace the more traditional additives used for this purpose. In the case of the crankcase application, the initial motivation was to replace traditionally used Zinc Dialkyle Dithiophosphates (ZDDPs) and thereby assist the durability and performance of exhaust treatment and accordingly reduce harmful emissions and subsequently enhance the performance of zinc-free formulations. Three key market segments were targeted initially with the aim of narrowing down as the project made progress. The project has been successful in demonstrating the potential benefits for both the crankcase application and greases for industrial bearings.
The technological barriers identified at the start of the project mainly relate to the commercial scale production, incorporation of nanoparticles into full formulations to make stable products and sustainability of their performance benefits.
Two specific nanoparticles considered within AddNano as additives to contribute to friction reduction and enhanced protection against wear have been tungsten disulphide (WS2) and molybdenum disulphide (WS2). Both of these materials are known to be highly lubricious. Tungsten disulphide has a layered hollow sphere structure with hexagonal crystal clusters. Surfaces formed have hexagonal networks with S-W-S molecules. The layers are connected by van-der-Waals forces, i.e. weak binding that can be broken up. Crystals are known to be very stable at high temperatures. Molybdenum disulphide is used in dry form or as a suspension in oils and greases (micron size in traditional formulations). It is lubricious due to its layered structure of S-Mo-S, without chemical bonds between Mo and S atoms. MoS2 particles form an adherent film on surfaces. At high pressure, when greases or oils are squeezed out, this film acts as a lubricant.
AddNano project, above all, aimed at demonstrating the performance benefits of lubricant formulations with nanoparticles and where such benefits could be demonstrated, addressed issues that could constitute barriers to full commercial-scale production of such lubricants.
The main objective of the AddNano Project has therefore been to overcome the technological barriers relating to the development of large scale market introduction of a new generation of lubricants incorporating nanoparticles in their formulation.
To achieve the market introduction of such advanced lubricants of improved properties and performance, in parallel to performance testing at bench and full scale, various processes from particle synthesis and manufacture to dispersion, stabilisation and final formulation have been developed throughout the project. Other project objectives included:
- Development of environmentally well-managed production methods that avoid potential for impact on health and release of harmful chemicals into the environment;
- identification and use REACH-compliant raw materials for the synthesis of MoS2 nanoparticles that are suitable for mass production for use in mainstream high-volume lubricants;
- preparation of process design methods based on improved understanding of the effects of particle and liquid properties on dispersion operations (scale-up of from laboratory scale to industrial scale);
- design and selection of process equipment for the industrial scale production of lubricants incorporating nanoparticles in their formulation using design rules and numerical models developed within the project;
- integration of fundamental understanding of tribological phenomena, applied research focussed on modelling of tribological behaviour of end-user materials and the development of lubricants with tailored tribological functions.


Project Results:
The project has been highly active and successful since its inception in October 2009.
Main activities, scientific and technical results and foreground generated are summarised in the paragraphs below.
Synthesis of nanoparticles and characterisation: Of the several synthesis routes explored in the initial stages of the project, six successful methods were developed to obtain MoS2 and WS2. These were tested in different formulations of crankcase and transmission oils and greases for industrial bearings. Two were retained for the rest of the project for further development, with potential for four others to be developed outside the project.

Electron microscopy images of some of the synthesised particles

Product formulation and characterisation: Whilst the ultimate target of the project was to develop one new formulation lubricant, having evaluated three applications in the first stage of the project: two lubricants could be formulated: a crankcase oil for passenger cars and a grease for industrial bearings.
Different formulations evaluated throughout the course of the project took into consideration the interaction of different additives, product performance and properties. Stability of intermediate and final products were tested and found to be excellent with comparable particle size distribution over a period of 24 months. Formulations were modified to adjust other additives to obtain target values of the fully formulated final product.

Example results from some of the stability tests performed:
(a) separation
(b) blotter tests
(c) sedimentation
(d) Particle Size Distribution

Scale up of synthesis: Full scale manufacture of one of the nanoparticles is currently possible; the manufacture of the other has been scaled up from a few grams to a few kilograms during the course of the project.
Products (intermediate and final) prepared from different batches including those from scaled up reactors were reproducible in terms of their performance and properties.
Performance testing: Lubrication conditions cover a wide range of regimes in the case of crankcase application, varying from hydrodynamic regime in engine bearings to elastohydrodynamic regime in valve train systems and mixed lubrication in piston ring/cylinder liner. In the case of greases, whilst this is predominantly elastohydrodynamic, under severe conditions boundary lubrication regime is covered.

Coefficient of friction in different lubrication regimes

Initial performance testing was conducted with different types of bench scale tribometers to evaluate the performance of different formulations. These results and product characterisation allowed screening and development of high performance formulations.

Performance results in terms of coefficient of friction with different formulations

Significant differences were noted in terms of the performance of different formulations, depending on the particle used, synthesis method, concentration and particle size distribution. The assessment of the comparative performance of different formulations is shown in terms of friction of coefficient above and wear tracks below.


Example results showing wear tracks on cylinder liner specimens obtained with three different engine oils: (a) zinc containing reference oil; (b) zinc free reference oil, (c) zinc free AddNano oil containing nanoparticles

Analyses of contact surfaces were performed to detect the composition of the tribofilm. Techniques developed\adapted allowed the observation of isolated nanoparticles between two contacting surfaces providing useful insight in terms of the mechanism of lubrication.

Use of High Resolution TEM to observe single nanoparticles under compression and shear.
Deformation, exfoliation of the layered structures can be seen leading to the formation of a tribolayer.


In addition to bench scale tribometers, performance evaluation included motored engine head tests using a diesel DOHC (Double Over Head Cam) engine directly driven by a rotating shaft connected to an electric motor, as shown below. In one test cycle (500 minutes), the rotating speed of the driving shaft was varied between 1000 and 4000 rpm. During the test, the resistance torque was monitored by using a 50 Nm torque transducer. The test cycle was repeated for a total duration of 250 hours corresponding to a distance of 60,000 km.

Experimental setup for the motored full scale engine head test

Process design, optimisation and scale up: Several processes are involved in the manufacture if the intermediate and final products as schematically shown below. Achieving these processes successfully and demonstrating the prospect of further scale up have been some of the main challenges at the start of the project to tackle as potential technological barriers.

Initially the incorporation of nanoparticles is required to ensure that they do not float at the surface of the oil or sediment but a suspension is formed so that they can subsequently be broken up to generate a fine dispersion. Different process devices considered included a stirred tank with traditional impellers and a specific design allowing powder incorporation into the impeller region and an in-line rotor-stator, such as Ytron ZC.

Ytron ZC for powder incorporation
Different protocols were assessed at the start of the project for the deagglomeration stage, also taking into consideration the smaller amounts of materials available initially. These included a stirred tank equipped with a sawtooth impeller, a Microfluidizer, batch rotor-stator, a stirred bead mill and the ultrasonicator. These studies included the determination of the mechanisms and rate of break up. It was possible to obtain a fine dispersion with most of these devices, but due to the differences in the specific power input and consequently in the kinetics of break up some devices took considerably longer time compared to others. An appropriate process device, operating mode and alternative designs which consist of a combination of equipment were identified for the final process design.

Different dispersion protocols considered


Once the appropriate equipment was identified for large scale manufacture of the concentrated intermediate product, efforts concentrated on scale up. The dispersion process could be scaled up by a factor of 10 whilst maintaining dispersion properties.


Particle Size Distributions obtained for the concentrated nanoparticle dispersion at small and large scale
Validated numerical models could be developed relating to nanoparticle manufacture, incorporation and deagglomeration processes. These models provide valuable insight in terms of the flow field in the process devices, which is otherwise impossible to determine, concentration gradients and specific power input. They can be further modified for other processes if required.
The deagglomeration process was optimised to achieve a fine dispersion within as short a time period as possible, thereby minimising the energy consumption. The optimisation exercise also took into consideration the potential wear of the equipment (and associated parts) and temperature rise during processing, which could be quite rapid under certain conditions, and hence the cooling duty required, which can be problematic in large scale.


Results from the optimisation of the deagglomeration process to reduce the processing time
Prototype design procedures were prepared relating to these processes documenting the approach to be taken. Such design guides can be modified further in the future for other applications.
The process relating to blending into final product was also evaluated and designed. Cost calculations relating to these processes allowed to assessment of the price of the final product.
HSE: Several activities have been undertaken as part of HSE assessment. The cellular toxicity (exposure of human pulmonary epithelial cells, A549) of WS2 and MoS2 particles from AddNano as well as cell-free molecular mechanism of toxicity of these particles were studied. The results can form the basis of materials safety data.

Bench top Diesel engine

A bench scale diesel engine was used to evaluate the fate of the nanoparticles through the engines, and to establish the likely health impacts of the nanoparticles in virgin form and as emitted by the diesel engines. Slight improvement in terms of NO and CO2 was detected with no significant effect O2 and CO.

Through engine-scale tests with a 1.9 L common rail diesel engine (Euro V) the possibility of an anomalous ash production and progressive accumulation inside the diesel particulate filter was excluded, i.e. the retention in the filter of the soot incombustible fraction, originated from current fuel and lubricant additives, did not cause any progressive reduction of the available filtration area, which would have increased the bare filter pressure drop at the end of each repeated regeneration.
In addition to this, AddNano engine oil showed a remarkable performance in terms of fuel consumption, which was one of the original targets of the ADDANANO project, showing a 5% improvement with respect to the current unmodified lubricant oil formulation. The fuel consumption was determined by weighing the fuel in the engine before and after each test.

LCA and RAMS: Project activities included a “Life Cycle Analysis” (LCA) and an analysis of “Reliability, Availability, Maintenance and Safety” (RAMS) for the different products. Both LCA and RAMS are original.
End-user survey conducted covered 85 participants to cross match the range of application and performance features found by Addnano consortium members and end-user needs. The objective of the survey was to ensure that the products formulated within AddNano are aligned with market requirements and expectations. The summary of customer feedback for the automotive and industrial lubes manufacturers and for the grease and aerosol manufacturers confirmed that the market introduction of newly formulated products containing nanoparticles in their formulation is unlikely to face an adverse reaction from end-users.
Demonstration: Final project activities focussed on demonstration of the benefits of new formulation lubricants under “real life” conditions.
For the engine oil, this was performed through a 20000 km long drive. Oil analysis, engine emissions and fuel economy tests were performed regularly every 5000 km. Emissions were measured using a Portable Emissions Measurement System (PEMS). No functional problems on the engine were noted during these road tests and fuel economy of the order of 2-3 % with respect to the standard base oil was measured.

Roller chassis dyno test A portable emissions measurement system A test vehicle (Lancia Delta with 2 L (PEMS) diesel engine) equipped with a PEMS.

For the new formulation grease, demonstration activities involved a pump (75 KW) used for the transport of wood pulp in a paper works factory during 1.500 h operation of under variable load. The first results were used for optimizing the EP/wear properties and the resistance to oxidation (operation life) and the final prototype was validated by means of the standard FAG bearing tests FE-8 (DIN 51819-2) and FE-9 (DIN 51821-02).


Pump in paper pulp factory used during demonstration tests for the industrial grease
The FAG testing demonstrated the satisfactory performance of the nanoparticles used for imparting EP/wear properties. Both wear measured in FE-8 (mw50 of rollers and mk50 of cage) and oxidation resistance in FE-9 (operating life F50) obtained values exceeding the typical standards of comparable multipurpose bearing greases, allowing for a differentiation in performance without compromising a reasonable cost of the final product

Results from standard FAG bearing tests

Dissemination activities included two well attended seminars with the development of teaching material, several conference presentations and papers, newsletters and press releases. These are listed for reference in Tables A1 and A2. A dedicated project website, open to public, was regularly updated:
http://sites.google.com/site/addnanoeu/home

Potential Impact:
During the course of the project, several post-graduate students and researchers at post-doctoral level were trained at both academic and industrial partners. The expertise and skills thus developed has enhanced employment capability of young researchers in Europe.
A patent search performed revealed several patents and a few competing technologies. A lot of the patents granted are recent (after the start of AddNano) and mainly from outside Europe, highlighting the importance of this project in maintaining Europe at a competitive edge. Any future manufacturing initiatives will mean further employment opportunities.
The project has demonstrated the benefits of using nanoparticles in lubricant formulations. Of these, the reduction of friction (from around 0.11 to 0.06 as determined in tribometers) and protection against wear (reduced scar diameter) result in reduced fuel consumption (of the order of 1-5%) and emissions (CO2 emission reduction estimated to be of the order of 1%) and can potentially prolong equipment lifetime and service cycles all of which have environmental and societal impacts.
Dissemination activities included

- Two well attended seminars:
• The first one in 2010 at Politecnico di Torino which was mainly aimed at academic researchers (undergraduate students performing research projects, postgraduate students undertaking Masters and PhD degrees, post- doctoral researchers and some lecturers) which was attended by around 50 people.

1st dissemination workshop
• The second one was held on 10th September 2013 in Torino, just before the 7th World Tribology Congress 2013- WTC 2013. This was attended by around 80 people from industry and academia.
• Both events were filmed and CDs containing presentations were prepared, contributing towards the development of teaching material which can be used further.

CDs containing AddNano dissemination workshop presentations organised by Politecnico di Torino which can be obtained from Main Contact Person: Prof. Debora Fino, Politecnico di Torino

- Several conference and journal papers were presented as part of dissemination activities, which are listed in Tables A1 and A2. These included two EC events: EuroNano Forum in 2013 and Industrial Technologies 2014. Presentations during conferences and professional society events were most helpful in establishing contacts with colleagues working in the field in terms of both exchange of information, future collaborations and to secure future business. They have also been an excellent means for the development of young researchers who presented their work. For example, Imen Lahouij at ECL worked on AddNano during her PhD project. Three of her conference posters received awards:
• Prize of the Best Poster presentation, International Nanotribology Forum, May 23-27 2011, Hoi an, Vietnam
• Platinum Level Poster Award, 68th Annual Meeting of Soc. of Tribologists & Lubrication Eng.- STLE, May 06-11, 2012, St Louis, USA

Prize of the Best Poster presentation, Collogue Indentation 2012, October 29-31 2012, Lyon, France- shown on the left

- Newsletters and press releases were sent to thousands of contacts in the field.
- A dedicated project website, open to public, has been updated regularly
http://sites.google.com/site/addnanoeu/home

Exploitation:
In total 12 exploitable products were developed during the project. Two main products are the new formulation engine oil and industrial grease. Nanoparticles synthesised through four different routes are other exploitable products. Expertise developed on dispersion processes, numerical models relating to these processes and particle synthesis, process design guides, LCA and teaching material also constitute exploitable products. The exploitation of some of these has already

List of Websites:
Contact details for the project and partners

Several details about the project can be found on the project web site: https://sites.google.com/site/addnanoeu/
List of beneficiaries with contact names are as follows:

i. VirtualPiE Ltd
Dr N. Gül Özcan-Taşkın,
VirtualPiE Ltd trading as BHR Group, College Road, Cranfield, Bedfordshire MK43 0AJ UK
Tel: +44 1234 756 422 Fax: +44 1234 750 074
E-mail: gozcan@bhrgroup.co.uk

ii. CIDETEC
Dr Iñaki Garcia
CIDETEC Parque Tecnológico de San Sebastián
Pº Miramón, 196
20009 Donostia-San Sebastián (Gipuzkoa), Spain
Tel: +34 943 30 90 22 E-mail: Iggarcia@cidetec.es

iii. CRF
Dr. Mauro Francesco Sgroi
Centro Ricerche FIAT, Strada Torino 50, 10043 Orbassano (TO), Italia
Tel: +390119083552 Fax: +390119083666 E-mail: mauro.sgroi@crf.it

iv. NML

v. InS
Dr. Francesca Pagliarulo
INS Sarl, rue Ampere, ZI Lyon Nord, 69730 Genay, France
Tel 0033-(0)478727848/ 0033-(0)647407673 Fax: 0033(0)4 78 91 23 05

vi. Krafft Lubricants
Mr. Pablo Aguirre
KRAFFT S.L.U. Ctra. Urnieta s/n,
20140 Andoain,SPAIN
Tel: +34 943 410 475 Fax: +34 410 487
E-mail: Pablo.aguirre@krafft.es


vii. LTDS\ECL
Prof Fabrice DASSENOY
LTDS
av Guy de Collonque,36
F 69134 ECULLY cedex-FRANCE
tel: +33(0)4 72 18 67 00 Fax: +33(0)4 78 43 33 83
email: fabrice.dassenoy@ec-lyon.fr

viii. Multisol
Ms Bénédicte Fenouil
Multisol France
10 avenue du Québec
Silic 547
91946 Courtaboeuf Cedex France
Tel/Fax: +33 (0)1 69 59 17 30 / +33 (0)1 69 59 16 49
E-mail : benedictefenouil@multisol-france.comNML

ix. Nanomates
Prof. Paolo Ciambelli
Centre NANO_MATES
University of Salerno
Department of Industrial Engineering
Via Giovanni Paolo II, 134
84084 Fisciano – Salerno, Italy
Tel. +39 089964151; Mobile: +39 3207979006
E-mail: pciambelli@unisa.it

x. Politecnico di Torino
Prof. Debora Fino
Politecnico di Torino,
Department of Applied Science and Technology
Corso Duca degli Abruzzi 24, 10129 Torino (Italy)
Tel. +39 011 090 4710; Fax + 39 011 090 4624;
E-mail: debora.fino@polito.it

xi. Stockholm University
Dr. Stefan Csillag , Professor in Physics Director of Studies
International co-ordinator
Fysikum AlbaNova
Stockholm University
S-106 91 Stockholm Sweden
Phone: +46 8 55 37 86 85 ; Mobile: +46 7 08 76 84 27 ;
Fax: +46 8 55 37 86 01 ;
E-mail: scs@physto.se

xii. Fuchs Lubricants
Dr. G. Kraft,
FUCHS Europe Schmierstoffe, Friesenheimerstr. 19, 68169 Mannheim, Germany
Tel.: + 49 (0) 621 3701-1778, Fax.: + 49 (0) 621 3701-7778,
E-mail: gunther.kraft@fuchs-europe.de