High Temperature Acid Hydrolysis of Cellulose for Alcohol Fuel Production

摘要

In the past decade, a concerted effort has been made to develop a process for converting renewable lignocellulosic feedstocks into ethanol fuels. This can be accomplished by the hydrolysis of cellulose and hemicellulose to their component sugars and subsequent fermentation of the sugars to ethanol. The hydrolysis may be accomplished by either acid or enzymatic processes. Acid processes are relatively fast, with reaction times on the order of seconds for high-temperature, dilute-acid processes, and minutes for low-temperature, concentrated-acid processes. Enzymatic processes have reaction times of one to two days. Acid processes have low yields (50 to 70% of theoretical), require expensive materials, and consume large amounts of energy, while enzymatic process offer higher yields and are carried out at low temperatures and pressures in inexpensive materials. This report provides a parametric analysis of the high-temperature, dilute sulfuric acid hydrolysis process and examines the effect of processing variations on yield, capital cost, and process economics. The study was conducted using a process simulation program developed by Chem Systems (1981a, 1981b). The model performs material and energy balances, estimates capital cost, and computes the cost of production. The results of this study are reported in greater detail in a report by the author (Wright 1983). The parametric analyses indicate the potential for significant reductions in the selling price of ethanol. The model utilized in this study is best suited for comparisons of processes and not predictions of absolute costs. However, results are reported and compared in dollars per gallon to provide a common measure of the economics of the processes. 6 references, 7 figures, 8 tables. (ERA citation 09:016108)