Life-Cycle Greenhouse Gas and Water Intensity of Cellulosic Biofuel Production Using Cholinium Lysinate Ionic Liquid Pretreatment

Publication Type

Journal Article

Date Published

09/2017

Abstract

Cellulosic biofuels present an opportunity to meet a significant fraction of liquid transportation fuel demand with renewable, low-carbon alternatives. Certain ionic liquids (ILs) have proven effective at facilitating hydrolysis of lignocellulose to produce fermentable sugars with high yields. Although their negligible vapor pressure and low flammability make ILs attractive solvents at the point of use, their life-cycle environmental impacts have not been investigated in the context of cellulosic biorefineries. This study provides the first life-cycle greenhouse gas (GHG) and water use inventory for biofuels produced using IL pretreatment. We explore two corn stover-to-ethanol process configurations: the conventional water-wash (WW) route and the more recently developed integrated high gravity (iHG) route, which eliminates washing steps after pretreatment. Our results are based on the use of a representative IL, cholinium lysinate ([Ch][Lys]). We find that the WW process results in unacceptably high GHG emissions. The iHG process has the potential to reduce GHG emissions per megajoule of fuel by ∼45% relative to gasoline if [Ch][Lys] is used. Use of a protic IL with comparable performance to [Ch][Lys] could achieve GHG reductions up to 70–85%. The water intensities of the WW and iHG processes are both comparable to those of other cellulosic biofuel technologies.

Journal

ACS Sustainable Chemistry & Engineering

Volume

5

Year of Publication

2017

Short Title

ACS Sustainable Chem. Eng.

Pagination

10176-10185

Issue

11

ISSN

2168-0485