Process and utility water requirements for cellulosic ethanol production processes via fermentation pathway

Abstract

In this study, the process and utility water requirements for cellulosic ethanol production via fermentation pathway were assessed on a volume-to-volume basis (i.e., gallons of water consumption per gallon of ethanol production) using the data reported in the literature. The water requirements were analyzed for a combination of three feedstocks (i.e., hardwood, corn stover, and switchgrass) and two pretreatment technologies (i.e., dilute acid and ammonia fiber expansion) under different water network configurations aiming for zero wastewater discharge. The results indicate that the process water requirement is significantly dependent on the selection of a pretreatment process and a feedstock, while the effective design and operation of a cooling tower offers an opportunity for saving utility water. © 2012 American Institute of Chemical Engineers.