A Study on Milling Pretreatment for Ethyl Alcohol Production from Cellulosic Woody Biomass

Milling of cellulosic woody biomass as preprocessing is one of the key technologies for an ethanol production by an enzymatic hydrolysis process. Generally a mechanical mill is used for grinding of woody biomass. However, because the efficiency of the normal vibratory ball mill is low, it is not suitable for grinding of woody biomass. Therefore, the most suitable condition of woody biomass for ethanol production is needed to develop the mill system. The purpose of this research is to get the optimum condition for the high enzymatic hydrolysis by the normal vibratory ball mill. As a result, it was clarified that average particle size of 20 ∼ 30 μm and cellulose crystallinity index of 8 ∼ 12 % is the optimum condition for the high enzymatic hydrolysis. In a commercial scale, the development of the mill system to achieve those conditions in a short time is necessary, and it became clear that the application of a special-rod mill or super-high-speed ball mill would be effective for commercial ethanol production.