The SUPRABIO project researches, develops and demonstrates a toolkit of novel generic processes together with advanced intensification and integration methodologies that can be applied to a range of biorefinery scenarios based on sustainable biomass feedstocks. Supporting economic and lifecycle assessment of the resulting gains in energy efficiency and conversion of renewable carbon, together with an implementation strategy based on a product mix with optimal value, will inform step changes that contribute to achieving a more secure and sustainable economy in Europe.
The concept of the biorefinery is a realistic response in Europe to the perceived need to reduce the dependence on fossil fuels for energy in the transport sector by moving toward biomass feedstocks. The main drivers are reducing carbon dioxide emissions (climate change), improving the security of energy supply and the economic opportunities thrown up by changing the technology basis of production and conversion. However, there are many issues and technical hurdles that must be overcome before biorefineries are realized on the ground and the project addresses these. Rather than build a project around a particular biorefinery type, the project focuses on certain critical unit operations that are at present limiting economic feasibility and which are sufficiently generic to be applicable to a range of biorefinery scenarios.
Cognisant of the debate around the use of agricultural land for energy crops, our project concentrates on currently the most economic feedstocks; lignocelluloses from sustainable forestry and agricultural wastes and the available organic waste streams from food industries and municipalities. The project also focuses on algae, because although currently very costly, land use is not an issue and there is considerable potential for improving growth rates and the efficiency of CO2 capture. Lipids from oilseed crops are also considered because whole crop processing from high lipid plants grown on less favourable land may have advantage.
The economics of producing biofuels is at present unfavourable and comparison with fossil fuels is very dependent on the price of oil. It is generally agreed that the best approach to improving the situation is to adopt a whole biorefinery approach. This means that the maximum value is obtained from a particular biomass by selecting the optimum mix of products (fuels, chemical intermediates, high added value chemicals, materials, energy). SUPRABIO goes beyond this by focusing on the intensification of critical process steps to improve the economics of building and operating equipment appropriate for smaller and intermediate scale refining and distributed production. In addition, SUPRABIO concentrates on process optimisation and sophisticated integration that considers whole Biorefinery management issues. Thus optimisation of material and waste flow within the biorefinery, water management and process energy requirements are all considered in addition to process technologies. In this manner we expect to couple optimum economic benefit to optimum usage of biocarbon and minimal GHG emission.
In SUPRABIO, the important steps were categorised as Production (selection of strains), Fractionation/Extraction (biomass into major components), Separation (solid-liquid, liquid-liquid, gas-liquid), Conversion (enzymatic, microbiological, catalytic) and Process Integration (gasification of process wastes, clean up, reactor/heat exchanger design), all to be linked by full Life Cycle Analysis.
Production: The scale of biomass availability is an issue here, to be coupled to the scale of producing products. Although it is possible to conceive of very large industrial plants fed by biomass, in many situations harvesting and transportation constraints will drive towards smaller refineries, perhaps fed by a mixture of feedstocks. In addition, multiproduct processes will inevitably require individual process steps at a smaller scale.
Fractionation/Extraction: This is a critical step in the biorefinery is fractionating biomass into major components (lignin, cellulose and hemicelluloses). Similarly fractionation of microalgae into constituent lipid, protein and carbohydrate components.
Separation into individual components becomes a key technology towards efficient utilization and conversion.
Conversion (enzymatic, microbiological, catalytic) of the intermediates is a core activity and the focus will be to identify highly selective agents and optimum conditions for improved efficiency and selectivity towards the desired products. In the case of the catalytic conversions to fuels, the objective is to improve overall efficiency, downsize plants and reduce costs.
Process integration: Process intensification and integration is a way to improve the economics of smaller scale production, but novel/improved technologies may also be required. For example, the gasification and clean up of biorefinery wastes for process energy and CO/H2 will be very different to that for large-scale electricity or CHP. Similarly, novel combinations of reactor design with catalyst or immobilized enzymes are required for both intensified and integrated conversion and processing. Separation and purification are frequently major factors in the economics of potential processes. These aspects are addressed in the specific activities, particularly developing dewatering and low moisture processing techniques.
Life Cycle Analysis: These processes will be subjected to full Life Cycle Analysis to quantify their impact on the use of energy and materials and their interactions with the environment. Options for integrating these potential routes will be studied within the project taking into account the energy requirements, aspects of engineering integration, emissions and the economics.
Putting the results of these activities together with market studies of the relevant fuels and high added value products, will allow the project to define biorefinery options for specific situations that are economic, sustainable, compatible with biomass resources and acceptable to society.