title: Understanding cost drivers and economic potential of two variants of ionic liquid pretreatment for cellulosic biofuel production.
abstract: BACKGROUND
  Ionic liquid (IL) pretreatment could enable an economically viable route to produce biofuels by providing efficient means to extract sugars and lignin from lignocellulosic biomass. However, to realize this, novel IL-based processes need to be developed in order to minimize the overall production costs and accelerate commercial viability. In this study, two variants of IL-based processes are considered: one based on complete removal of the IL prior to hydrolysis using a water-wash (WW) step and the other based on a "one-pot" (OP) process that does not require IL removal prior to saccharification. Detailed techno-economic analysis (TEA) of these two routes was carried out to understand the cost drivers, economic potential (minimum ethanol selling price, MESP), and relative merits and challenges of each route.
  
  
  RESULTS
  At high biomass loading (50%), both routes exhibited comparable economic performance with an MESP of $6.3/gal. With the possible advances identified (reduced water or acid/base consumption, improved conversion in pretreatment, and lignin valorization), the MESP could be reduced to around $3/gal ($3.2 in the WW route and $2.8 in the OP route).
  
  
  CONCLUSIONS
  It was found that, to be competitive at industrial scale, lowered cost of ILs used and higher biomass loadings (50%) are essential for both routes, and in particular for the OP route. Overall, while the economic potential of both routes appears to be comparable at higher biomass loadings, the OP route showed the benefit of lower water consumption at the plant level, an important cost and sustainability consideration for biorefineries.
authors.affiliation: Joint BioEnergy Institute, 5885 Hollis Street, 94608 Emeryville, CA, USA ; Physical Biosciences Division, Lawrence Berkeley National Laboratory, 94720 Berkeley, CA, USA.
authors.forename: Nvsn Murthy
authors.initials: NM
authors.lastname: Konda
authors.affiliation: Joint BioEnergy Institute, 5885 Hollis Street, 94608 Emeryville, CA, USA ; Biological and Materials Science Center, Sandia National Laboratories, 94551 Livermore, CA, USA.
authors.forename: Jian
authors.initials: J
authors.lastname: Shi
authors.affiliation: Joint BioEnergy Institute, 5885 Hollis Street, 94608 Emeryville, CA, USA ; Biological and Materials Science Center, Sandia National Laboratories, 94551 Livermore, CA, USA.
authors.forename: Seema
authors.initials: S
authors.lastname: Singh
authors.affiliation: Joint BioEnergy Institute, 5885 Hollis Street, 94608 Emeryville, CA, USA ; Physical Biosciences Division, Lawrence Berkeley National Laboratory, 94720 Berkeley, CA, USA ; Department of Chemical Engineering, University of California, 94720 Berkeley, CA, USA.
authors.forename: Harvey W
authors.initials: HW
authors.lastname: Blanch
authors.affiliation: Joint BioEnergy Institute, 5885 Hollis Street, 94608 Emeryville, CA, USA ; Biological and Materials Science Center, Sandia National Laboratories, 94551 Livermore, CA, USA.
authors.forename: Blake A
authors.initials: BA
authors.lastname: Simmons
authors.affiliation: Joint BioEnergy Institute, 5885 Hollis Street, 94608 Emeryville, CA, USA ; Physical Biosciences Division, Lawrence Berkeley National Laboratory, 94720 Berkeley, CA, USA ; Dow Center for Sustainable Engineering Innovation, University of Queensland, St. Lucia, QLD, Australia.
authors.forename: Daniel
authors.initials: D
authors.lastname: Klein-Marcuschamer
keywords: Ionic liquid pretreatment; Lignin valorization; Lignocellulosic biofuels; One-pot process; Process modeling; Techno-economic analysis