Diesel fuel contains long chain n-alkanes which can phase separate at low temperatures and result in formation of large flat wax crystals. Such wax crystals can block fuel filters which results in fuels starvation and vehicle failure. These problems have become exacerbated by the introduction of biofuel, with thousands of vehicles failing in winter conditions. To-date, these issues have been addressed by developing chemistries to nucleate wax (and hence produce more smaller crystals) and also by introducing polymers which incorporate in a plane of crystallization and hence produce needle-like crystals. Both approaches reduce filter blockages, through modification of crystal structure. However, wax crystals do still form and the possibility of filter blockage and deposit formation throughout the fuel system (including in fuel injectors) does still exist.
If wax nucleation could be effectively understood and controlled, then tailored cold weather properties could be designed. Recent research has highlighted the presence of ordering prior to nucleation of crystals. If the factors affecting such pre-nucleation ordering were understood, it may be possible to prevent (or control) nucleation and hence wax crystal formation. Nucleation of wax then occurs via two possible mechanisms: instantaneous and progressive, which are influenced by the composition of the fuel (Paraffinic, Olefinics, Napthenics, Aromatics etc).The aim of the project will be to develop an understanding of the fundamental principles involved in pre-nucleation ordering of n-alkanes and biofuel components and to link instantaneous and progressive nucleation to the chemical composition of the fuel. This work will be used as a way of automating additive selection on 'Fuel tiles'
This project is mostly experimental with some complementary molecular, solid-state and morphological modelling required. The majority of experimental facilities are available at the University of Leeds in the School of Chemical and Process Engineering. Various techniques will be used throughout the project including polythermal (metastable zone widths and KHBR analysis) and isothermal (induction time) crystallisation studies, x-ray diffraction, crystal 16, thermochemical methods, optical microscopy and small angle x-ray (SAXS) both in Leeds and at Diamond Light Source.

Potential Impact:
The establishment of a CDT in Complex Particulate Products and Processes will have a range of positive impacts, both academic and socio-economic. We identify four groups of beneficiaries: industry partners and associated supply chains; academia; the general public; and government policy makers.

The research undertaken within the CDT will have a strong links to current UK industry needs. Particle science and engineering underpins a wide-range of manufacturing sectors in the UK including foods, home & personal care, healthcare, pharmaceuticals, agrochemicals, fine chemicals, catalysts and coatings. The CDT will support a highly significant part of the UK manufacturing base; a UK strategic sector that provides direct employment for 214,000 people and supports several hundred thousand additional jobs throughout the economy [UK Trade and Industry Report 2009: Chemicals - the UK advantage: Adding value for global investors and industry].

Clearly, the research outputs of 50 strategically-focused PhD research projects will significantly enhance knowledge in the area that will be proactively transferred to industry. Given our normal expectations, many of the CDT projects will lead to high-quality papers in the scientific literature thereby advancing our scientific and engineering understanding and providing impact within the academic community. It is also a key aim of the CDT to work across the boundary of science and engineering with a focus at the chemistry/chemical engineering interface. This is an area of current need and has been highlighted in a number of reports for investment, most recently the EPSRC Review of the Chemistry/Chemical Engineering Interface 2010/11. A CDT at this interface will build innovative approaches to integrated training where graduates are comfortable with the 'whole process', notably the impact that "small" decisions taken in product design can have on the efficiency and sustainability of manufacturing processes.

Moving beyond the traditional disciplinary boundaries and conventional research training approach, we will actively build teams clustered in a target area as is done in industry. For example, linking PhD projects on particle design, product stability and process development. Working together, the students can build a shared understanding of upstream and downstream process opportunities as well as understand any limitations that will ultimately affect the adoption of their research. This will have positive benefits for UK based industry, providing research leaders capable of driving innovation and creativity in this critical industry sector. Ultimately, there will also be benefits that accrue to the general public through the enhanced competitiveness of this critical manufacturing sector to the UK economy.

There is a need for graduates who understand how changes in ingredient quality, particle properties and/or formulation of a product can affect its processing and manufacturing. This links to the TSB high-value manufacturing strategy to apply 'leading-edge technical knowledge' to the 'creation of products' underpinning a technology-led economy where 'innovation in manufacturing' is a central theme. This addresses a government strategic agenda. The shortage of highly trained researchers to support novel and sustainable manufacturing approaches in this area has also been explicitly noted from our survey of 20 major manufacturing companies, highlighting a difficulty in finding engineers and scientists with the necessary skills. Across this space, there is a strong requirement for engineers and physical scientists who can iteratively translate novel materials discovery through the design and development of viable manufacturing processes, into innovative high-quality products. The graduates from this CDT will have a significant impact on the industrial and academic research and development capacity in this important area as the next-generation of research leaders in the field.