Abstract: Described are methods for pretreating lignocellulosic biomass that comprise thermally conditioning the biomass by flow processing an aqueous slurry of the biomass through an outer passage(s) of one or more heat exchange devices while circulating a heat exchange fluid through an inner passage(s) of the heat exchange device(s). Also described are methods for producing fermentation products, especially ethanol, from the pretreated biomass.

Abstract: Described are methods for pretreating lignocellulosic biomass that comprise passing a hot aqueous biomass slurry through a heat exchange passage from an inlet to an outlet and locally regulating pressure in the passage by feed of a pressurized liquid medium to one or more intermediate locations of the passage. Also described are methods for producing ethanol from the pretreated biomass.

Abstract: The disclosure describes a process for the conversion of lignocellulosic biomass to ethanol utilizing a dicarboxylic acid such as maleic acid as an enzyme mimic to hydrolyze the hemicellulose and cellulose of the biomass. Controlling the condition of the maleic acid hydrolysis can selectively hydrolyze the hemicellulose giving as a result a liquid portion rich in xylose and a solid portion rich in glucan. The glucan can be further hydrolyzed to produce a glucose containing material. The sugar materials can be fermented to produce ethanol which is recovered. The dicarboxylic acid is then recovered from the residue left after the ethanol is removed from the fermentation material, and the recovered dicarboxylic acid is recycled to the beginning of the process to treat additional lignocellulosic biomass.