SIMULATION OF ETHANOL-PRODUCTION PROCESSES BASED ON ENZYMATIC-HYDROLYSIS OF LIGNOCELLULOSIC MATERIALS USING ASPEN PLUS

The process simulator ASPEN PLUS was used for simulation of an ethanol production process based on enzymatic hydrolysis of lignocellulosic materials. The effect of water recycling, necessary to reduce the amount of waste water and to increase the ethanol concentration in the feed to the distillation, was investigated. For a process based on 20 t/h raw material, the amount of waste water can be reduced from 70.7 t/h, without recycling, to 7.1 t/h. Furthermore, the ethanol concentration in the distillation feed increased from 2.5 to 10%. The concentration of byproducts and possible inhibitors increased by a factor of 20-40 in the hydrolysis and fermentation steps. This gives new conditions for future hydrolysis and fermentation experiments.