Production of ethanol with reduced contaminants in a cellulosic biomass based process with rectification column and molecular sieves

摘要

Processes for producing ethanol from fermentation systems employing cellulosic feedstocks are provided, where contaminants prevalent from biomass hydrolysate fermentation are managed. The management of contaminants allows recycle of process water between the fermenter vent scrubber and rectification column, thereby removing the need for fresh water to the scrubber. After fermentation (101), the stream is sent to a beer column (103), a rectification column (111), a molecular sieve (113) and then a last product distillation column (118).