The corn stover (comprised of stalks, leaves, cobs, and husks), is delivered to the feed handling area (A100) for storage and size reduction. From there the biomass is conveyed to pretreatment and detoxification (A200). In this area, the biomass is treated with dilute sulfuric acid catalyst at a high temperature (about 190C) for a short time, liberating the hemicellulose sugars and other compounds. Separation with washing removes the acid from the solids for neutralization. Overliming is required to remove compounds liberated in the pretreatment that are toxic to the fermenting organism.