Technoeconomic analysis to nurture advances in ionic liquid pretreatment towards economically sustainable cellulosic biorefineries

Over the last decade, ionic liquids (ILs) have received increasing attention in biomass pretreatment applications. While research efforts focused on IL pretreatment have improved our scientific understanding of underlying mechanisms, further channeling these research efforts in an informed direction can help accelerate the progress towards commercially viable IL pretreatment technologies. To this end, at Joint BioEnergy Institute (JBEI), technoeconomic analysis (TEA) is used to help scientists take informed decisions. Our recent TEA work emphasized the importance of high biomass loading, high IL recovery, low IL and water usage to ensure the prospective cellulosic biorefineries can indeed be economically sustainable using these green solvents. Furthermore, these pretreatment technologies need to be integrated into biorefineries while minimizing any negative impact on the overall process economics. This is challenging, as there are significant trade-offs amongst these multiple objectives. Given the numerous possible combinations of cations and anions, however, it is possible to design ILs that are efficient in pretreatment while minimizing negative impact on downstream operations. By combining this tunable nature of ILs with the novel process design and operational concepts, scientists at JBEI are developing advanced pretreatment technologies. A recent advancement in this direction includes the development of a novel one-pot (OP) process that is capable of high yields at high-gravity (HG) conditions, while minimizing the use of water and IL. Our initial TEA has shown that the OP process has the potential to reduce minimum ethanol selling price (MESP) to below $3/gal.