The recycle of sulfuric acid and xylose in the prehydrolysis of corn stover

Ethanol may be produced from agricultural residues by using a two-stage acid hydrolysis followed by acid recovery, fermentation, and distillation. With sulfuric acid as a catalyst, xylose-rich and glucose-rich streams can be obtained from corn stover in the prehydrolysis and hydrolysis steps, respectively. After acid separation, the sugar solutions are fermented to ethanol and concentrated by distillation.