Conversion of biomass to sugars via ionic liquid hydrolysis: Process synthesis and economic evaluation

Replacement of fossil fuels with new sustainable resources is becoming crucial due to depleting petroleum reserves, increasing global energy demand, and arising environmental concerns. Lignocellulosic biomass can be an alternative to fossil resources as a sustainable and environmentally friendly feedstock for producing chemicals and fuels. One of the major challenges of biomass-based technologies is to extract sugars that are covalently trapped inside the lignocellulosic biomass efficiently. Recently, ionic liquids (ILs) have been recognized as promising solvents for mild and rapid hydrolysis of biomass feedstocks with higher sugar yields. In this study, we first develop and then evaluate an IL-based biomass hydrolysis strategy for large-scale production of fermentable sugars from corn stover. Toward this aim, we develop a process simulation model based on the experimental studies reported by Binder and Raines (P Natl Acad Sci USA 107: 4516-4521(2010)) and a simulated-moving-bed (SMB) system. We identify that the major cost driver is the IL cost. Our analysis suggests that process alternatives with lower IL consumption and/or separation strategies that would allow higher recycle of ILs should be studied.