(276f) Towards a New Paradigm in the Ionic Liquid Pretreatment for the Production of Lignocellulosic Biofuels: Technoeconomic Insights

Ionic liquids (ILs) have been receiving increasing attention in biomass pretreatment applications (Konda et al., 2014 and 2015) as some ionic liquids are shown to be very efficient in biomass pretreatment. Among several benefits of ionic liquids in general, they are often regarded as green solvents due to their negligible volatility. More importantly, given the availability of numerous anions and cations, it is often possible to tune their properties to suit specific application(s) by appropriately selecting the combination of anion and cation. Specific to biomass pretreatment, some ionic liquids are shown to be feedstock agnostic (Li et al., 2013) which is a very desirable characteristic especially given the uncertainty with feedstock supply and quality (e.g., seasonal variations). Such a technology can be potentially disruptive and can play a critical role in enabling large-scale cellulosic biorefineries.

To tap into the full potential of ionic liquids, however, it is important that the processes are designed such that they are economically viable as well as environmentally sustainable. These criteria demand for minimal/reduced use of any other chemicals (e.g., co-solvents, water) and energy footprint in the entire process. Furthermore, given the highly integrated nature of these cellulosic biorefineries, these pretreatment technologies need to be developed in such a way that they can be â??plugged-inâ?? while minimizing any negative impact on the other sections of the process (including downstream). Realizing such a process is often challenging as there exists significant trade-offs amongst these criteria. This emphasizes the need for greater insights into the mass and energy balances of such complex processes. To this end, with the help of virtual biorefinery models, technoeconomic analysis (TEA) offers invaluable guidance to nurture technological advances. Equipped with technoeconomic insights, scientists at Joint BioEnergy Institute (JBEI) are harnessing the tunable nature of ILs, together with the novel process design and operational concepts, to develop advanced pretreatment technologies. Our previous TEA work (Konda at al., 2014) 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. A recent advancement in this direction includes the development of a novel integrated process that is capable of high yields under high-gravity (HG) conditions, while minimizing the use of water and IL. TEA revealed that the continued developments with the proposed integrated process could potentially reduce minimum fuel selling price (MFSP) to below $3/gal.

References:

• Konda et al. (2014). Understanding cost drivers and economic potential of two variants of ionic liquid pretreatment for cellulosic biofuel production. Biotechnology for Biofuels 7: 86.
• Konda et al. (2015). Towards a cost-competitive ionic liquid based pretreatment: Insights from technoeconomic analysis. AIChE Annual Meeting, November 2015, Salt Lake City, UT. 
• Li et al. (2013). Comparing the recalcitrance of eucalyptus, pine, and switchgrass using ionic liquid and dilute acid pretreatments." BioEnergy Research 6, no. 1 (2013): 14-23.