Cellulosic Bioethanol Production

This chapter discusses some aspects of various separation technologies applied in bioethanol production from lignocellulosic materials. Bioethanol can be produced from lignocellulosic biomass using several different process configurations. The main energy-demanding process steps in lignocellulosic ethanol production are distillation to concentrate the ethanol, adsorption to remove the final content of water, and, optionally, evaporation either of the sugar solution before fermentation or of the stillage stream, as an option to anaerobic digestion, and drying of the solid residue, if this is required. The dehydration of ethanol using adsorption on zeolites is performed in two packed columns, where one is adsorbing water while the other is regenerated. One of the most important issues is to verify all process steps in an integrated way at a pilot and/or demonstration scale. The step from pilot- and demonstration-scale production of lignocellulosic ethanol to competitive full-scale production requires further reduction of the production cost.