Process Intensification for Acceleration of Bio & Chemo Catalysis in Biorefining

Biorefineries take as their feedstock materials from sustainable sources and ideally from non-food competitive sources. These materials are converted into valuable materials which may be used directly in products such as emollients for skin care creams or flavour and fragrances. Alternatively they may in turn be a raw material for a subsequent process which produces more complex products such as a monomer used for production of polyurethanes. However the existing process technologies have been designed for petrochemical based feedstocks. Such processes and the associated equipment have been refined over decades to be optimal for these chemistries and materials. Even when new technologies become available the cost of scrapping old process facilities and replacing them with new equipment may make it economically unattractive. Since the biorefinery industry is still developing there is a significant opportunity to introduce new and innovative processes and process equipment before long term capital investments are irrevocably made. The project seeks to evaluate one such extremely novel proprietary mixing technology which is already producing technology patents in adjacent industry sectors but has not to date been considered in biorefining. Many operations in biorefineries involve using water-insoluble materials. This means that there are solid particles (eg plant material) or droplets of liquids (eg oil) in the reaction mixture. Problems arise because the catalysts or reagents needed to convert the insoluble materials to products have to be dissolved in the water. Therefore, the reactions have to take place at the interface between the solid or oil and the water. In such reactions the intimate mixing of the feedstock and the catalysts is crucial to rapid conversion. We have developed a new type of mixing process that can vastly increase the surface area of the feedstock by producing smaller drops and particles. We aim to demonstrate the opportunities of such a novel combination of chemistry, biology and engineering through a focussed feasibility study with two example systems. In the first system we look at the degradation of waste lignin from biorefineries and the lignin present in biomass by commonly available enzymes. Lignocellulosic biomass as exemplified by wood, straw etc. is the single biggest source of sustainable organic materials. However the lignin fraction of this biomass is resistant to all but the most aggressive of chemical treatments and, whilst enzymes are responsible for the degradation of lignin in nature, they are much too slow for commercial processes. Nevertheless, lignin is one of the few sources of aromatic compounds in renewable feedstocks, and these are important industrial products. Therefore, a commercially viable route to lignin degradation would be extremely attractive to industry. In the second system we aim to take plant oils from biorefinery feedstock and, rather than converting them all to biodiesel, our goal is to oxidise them to more valuable intermediate feedstocks, such as materials used to prepare plastics. Thus we partly replace plastics made from oil with plastics made from plants,while also generating opportunities for new industries associated with the biorefinery. For both examples the conversions will be achieved in water without the aid of any of the additional chemicals which are traditionally introduced to overcome processing problems or to condition raw materials to make them easier to work with. Therefore, the mixer will simplify the processes and reduce waste, and also decrease energy consumption through the elimination of extra processing steps associated with separation and purification. As all of these things add to the cost of producing a chemical and may produce pollution, successful integration of the chemistry, biology and engineering will yield cleaner products from renewable resources, offering potential business opportunities.

This proposal addresses 'enhancing product value', while providing capability in 'integrative bioprocessing'. The Ultra Mixing and Processing Facility (UMPF) provides engineering capability to demonstrate that clean bio- and chemo-catalysis can be used, as integrated unit operations adjunct to the fuel production stream of the biorefinery, to produce high value aromatics from lignin and monomers from unsaturated oils. The examples chosen to demonstrate the valorisation of by-products of biofuel production are (a) production of monomers from oils in biphasic systems and (b) enzymatic processing of recalcitrant lignin fractions. Both examples rely directly on the use of a novel proprietary Process Intensification technology (UMPF) to overcome mass transfer limitations. Application specific knowledge is provided by University of Bath and Nottingham respectively. The UMPF has been shown in a parallel industry sectors to improve energy efficiency of distributive and dispersive mixing process to produce biphasic systems with large surface area. Scalability is built into the project, as are cleaner processing, reduced waste, energy efficiency and optimised unit operations; concepts central to the environmental, social and economic sustainability of integrated biorefining processes. The basic principles of the UMPF design are a uniform process experience to all molecules and maximisation of the specific area to increase the rate of intra and intermolecular events. We believe that these principles will lead to processes with better selectivity and enable reactions to occur with reduced or even no aids such as phase transfer catalysts, (hazardous) solvents and surfactants. Resulting sustainability gains will be assessed through the used of structured approaches such as Product-Driven Process Synthesis methodologies which are suited for developing conceptual designs and which will support more comprehensive analysis (e.g. life cycle analysis) in follow on proposals.

The impact of demonstrating that biphasic chemical reactions can be achieved efficiently without mediation of added auxiliaries such as the quaternary ammonium salts usually applied as phase transfer catalysts or volatile organic compounds used as co-colvents extends far beyond the examples of chemical product valorisation described in this integrated bio-refinery application. The Centre for Sustainable Chemical Technologies (CSCT), University of Bath has industrial associates, who are engaged in collaborative research with the Centre. Information sharing events are held periodically, notably the CSCT's summer seminar programme where industrialists, academics, students and other associates are brought together to share information. This will provide a forum for greater sharing of the results of this project directly with potential industrial development partners who are engaged in the development of more sustainable practices in the chemical industry. (Clearly any such dissemination will follow clearance according to the rules and guidelines of the IBTI initiative.) Papers will be prepared for high-profile journals and Scott is regularly invited to speak at academic conferences (for e.g. the Gordon Research Conference on Green Chemistry) providing a further forum for knowledge sharing. This proposal incorporates a significant training element, including an MRes or part of a PhD project with a student from Bath (the project is too limited in time to make this the subject of a full PhD project), but there are opportunities to extend this through direct interaction with the students in the Doctoral Training Centre in Sustainable Chemical Technologies. Results would be as a case study in a course entitled 'Clean Technology', which deals with process intensification and green chemistry and the collaboration would be extended to include DTC student PhD projects. The sustainability impact of such process intensification and cleaner chemical processes must be measured on a case-by-case basis as proper benchmarks and appropriate tools, such as Life Cycle Assessment must be applied. The data gathered in this feasibility project will allow demonstration of such comparisons in a form that will facilitate discussion of future projects with industrial partners, utilising the lessons learned in this feasibility study. Such comparisons would form an excellent basis for press releases and presentations at knowledge sharing events, such as the CI-KTNs knowledge dissemination events.