(672e) Alternative Low-Cost Process for the Hydrolysis of Lignocellulosic Materials for Bioethanol Production

The Energy Policy Act of 2005 (EPA2005) provides incentives for the production of up to 1 billion gallons of cellulosic ethanol by 2015. By 2012, 250 million gallons of bioethanol must be produced from qualified cellulosic materials. A solicitation of up to three integrated biorefinery demonstration projects was issued by U.S. Department of Energy on Feb. 22, 2006 for the demonstraction of the production of bioethanol using lignocellulosic feedstocks with a total of 80 million dollars. An efficent and cost effective conversion technology is needed in order to convert lignocellulosic materials such as wood chips, corn stover and wheat straw to bioethanol or other commodity chemicals in a biorefinery. Many different conversion schemes have been proposed and tested in the laboratory and various scale piloting factilities for the conversion of biomass. These include concentration acid hydrolysis, dilute acid hydrolysis, and dilute acid pretreatment combined with enzymatic hydrolysis. Among these, the most desirable technology is the dilute acid/enzymatic hydrolysis process and it is pursued by several companies around the globe. TVA has studied and piloted the concentrated and dilute acid hydrolysis processes in the past 20+ years. Many testings have also been carried out for the dilute acid pretreatment and enzymatic hydrolyiss process. It was found that a more efficicent and cost effective technology is needed to propel the cellulosic ethanol industry to reach the 1 billion gallon goal. A new process combines the delignification and aqua hydrolysis technology was recently invented and developed at TVA. This innovative process initially removes some lignin by heating the biomass with a delignifying chemical at elevated temperature without biomass hydrolysis. The second stage completely hydrolyze the hemicellulose without any acid. The remaining cellulose can be hydrolyzed to glucose by separate acid hydrolysis or enzymatic hydrolysis. The new process doesn't require special alloy reactor and produces little degradation products. Higher value co-produce could be produced to improve the economics of the biorefinery. This presentation will describe such process and highlights its advantages over other biomass conversion processes.