MODELING AND OPTIMIZATION OF THE DILUTE-SULFURIC-ACID PRETREATMENT OFCORN STOVER, POPLAR AND SWITCHGRASS

Lignocellulosic biomass may be used as a potential renewable feedstock for biochemical production of ethanol as an alternative transportatio n fuel. However cellulose, which is the major source of fermentable su gars in these materials, is protected by a network of lignin and hemic ellulose. The dilute-sulfuric-acid pretreatment removes this protectin g shield and makes the cellulose more susceptible to enzymatic digesti on. In this study, three lignocellulosic feedstocks (i.e. corn stover; poplar and switchgrass) were pretreated with dilute sulfuric acid (0. 6, 0.9 and 1.2% w/w) at relatively high temperatures (140, 160 and 180 degrees C) in a Parr batch reactor. The hydrolysis of hemicellulose t o its monomeric constituents and possible degradation of these monomer s were modeled by a series of first-order reactions. The kinetic param eters of two mathematical models for predicting the percentage of xyla n remaining in the substrate after pretreatment and the net xylose yie ld in the liquid stream were determined using rite actual acid concent ration in the reactor after accounting for the neutralization effect o f the substrates. (C) 1997 Elsevier Science Ltd.