Patent ID: 9574212
Date: 2017-02-21
CPC Classifications: B01D,C12M,C12P,C12Y,D21C,Y02E

Claim:
1. A process for producing a fermentation product from a lignocellulosic feedstock comprising: (i) soaking the lignocellulosic feedstock in a liquid comprising water to produce a soaked feedstock; (ii) at least partially dewatering the soaked feedstock to produce an at least partially dewatered feedstock; (iii) feeding the at least partially dewatered feedstock to a heating device; (iv) adding steam and acid to the heating device, said steam heating the at least partially dewatered feedstock to a first temperature to provide a heated feedstock, said acid comprising at least one of sulfur dioxide and sulfurous acid; (v) pretreating the heated feedstock in the presence of the acid in a pretreatment reactor to produce a pretreated feedstock, said pretreatment reactor disposed downstream of said heating device; (vi) hydrolyzing cellulose in the pretreated feedstock with cellulase enzymes to produce glucose, wherein the concentration of dissolved solids in the pretreated feedstock fed to the hydrolysis is at least about 50% of the concentration of dissolved solids in the pretreated feedstock produced in step (v); and (vii) fermenting the glucose to produce the fermentation product.