An Experimental Investigation on Cellulosic Biofuel Manufacturing: Effects of Biomass Particle Size on Sugar Yield

Biofuels made from cellulosic biomass are an alternative to petroleum-based liquid transportation fuels. A key barrier to cost-effective manufacturing of cellulosic biofuel is low sugar yield in enzymatic hydrolysis. Particle size and crystallinity index of cellulosic biomass are two important parameters in enzymatic hydrolysis. The current literature contains many experimental investigations about effects of biomass particle size on sugar yield. However, particle size, often reduced by ball milling, is correlated with crystallinity index. Changes in particle size usually cause changes in crystallinity index. Therefore, particle size and crystallinity index may have confounding effects on sugar yield. Relations between particle size and sugar yield are not clear. This paper reports an experimental investigation on sugar yields from switchgrass particles produced by three methods: cutting milling, hammer milling, and manual cutting. The particles have different sizes but the same crystallinity index. Results show that there are no significant differences among sugar yields from these particles of different sizes. Particle size within the tested range has no significant effects on sugar yield.