Abstract: The invented process separates main components in lignocellulosic biomass, specifically hardwoods, softwoods into lignin and fractions of high purity sugars which are used for ethanol production. The invented process comprises of treatment stages at high temperature and high pressure with hydrochloric acid or sulfuric acid. Residual lignin and extractives in the cellulosic solid fraction are selectively removed by chemical treatments of sodium chlorite, anhydrous acetic acid, chlorine and chlorine dioxide to enhance the purity and biological conversion of cellulose to ethanol. The pre-hydrolysate generated from the acid treatment stage, containing xylose, arabinose, galactose, glucose and the purified cellulosic fraction are enzymatically hydrolyzed and fermented to produce ethanol. Significant amount of lignin from the process is recovered as a by-product.

Abstract: A continuous and modular process converts lignocellulosic materials for the production of ethanol principally and/or chemicals such as methanol, butanediol, propanediol, hydrocarbon fuel, etc. Renewable lignocellulosic biomass such as but not all inclusive hardwoods (gum, beech, oak, sweet gum, poplar, eucalyptus, etc.), soft woods (pines, firs, spruce, etc.), corn stovers, straws, grasses, recycled papers, waste products from pulp and paper mills, etc can be used as feedstock. The process is designed to be modular and the feed entry point can be selected to adapt to different biomass feedstock. Lignocellulosic biomass such as hardwood and softwood are subjected to chemical/pressure treatment stages using potent and selective chemicals such as sodium chlorite/acetic acid (anhydrous) and chlorine/chlorine dioxide to separate the main components—lignin, cellulose (glucose) and hemicelluloses (xylose, arabinose, galactose)—into three process streams.