AN EVALUATION OF 2 ACID-HYDROLYSIS PROCESSES FOR THE CONVERSION OF CELLULOSIC FEEDSTOCKS TO ETHANOL AND OTHER CHEMICALS

The Tennessee Valley Authority (TVA) has been actively involved in the development of acid hydrolysis processes for the conversion of cellulosic feedstocks to ethanol since 1981. At that time, the TVA renewed earlier work conducted in the 1950s with the USDA Forest Products Laboratory to develop a dilute sulfuric acid hydrolysis process. Hydrolysis research at the TVA was further expanded in 1983 with the development of a concentrated sulfuric acid hyrolysis process for converting cellulosic feedstocks to sugars for ethanol production. Both processes are being developed in laboratory-, bench-, and pilot-scale studies. Ethanol yields from the two processes are 63 gal/t using dilute acid hydrolysis and 72 gal/t using the concentrated acid hydrolysis. An economic assessment of the two processes has been conducted using a base-case, commercial-scale design for producing 11M gal/yr of ethanol. Hardwoods and corn stover are used as feedstocks for the dilute and concentrated sulfuric acid hydrolysis processes, respectively. This paper will evaluate the effects of both internal and external factors on ethanol production costs. The sensitivity of these costs to technology, market, and economic changes will be presented. © 1990 Humana Press Inc.