Two-Stage Fractionation of Hardwoods

A two-stage lignocellulosic biomass fractionation process consisting of a formic- or acetic acid-reinforced wood autohydrolysis step followed by an ethanol-water treatment was applied to a mixture of Southern hardwood chips. The wood products in the hydrolysate were mostly monomeric xylose, other monomeric sugars, polymeric hemicelluloses, acetic acid, and a relatively small amount of lignin. The second step mostly dissolves sulfur-free lignin, while the fibrous residue consists mainly of cellulose fibers, which may be used for liquid fuels or pulp production. The yield composition, and quality of these products were determined as a function of treatment conditions, with the aim to develop an economic and robust biorefinery fractionation technology.