Evaluation Of Size Reduction And Storage Methods For The Conversion Of Lignocellulosic Biomass

Concerns of over global climate change and unstable petroleum supply have ledto the urgent development of alternatives to fossil oil as an energy source.Lignocelluloses-based renewable energy (such as cellulose ethanol) is potential tocontribute to meet the energy demand.Size reduction and biomass storage are the essential process for biomassutilization. Effects of biomass particle size and dry/wet storage on the efficiency ofsteam explosion pretreatment and enzymatic hydrolysis are systematic investigated inthe present study. To our knowledge, this is the first systematically study on theeffects of particle sizes and storages on the conversion of corn stover biomass tofermentable sugars by steam explosion pretreatment.Sugar recoveries and conversions of corn stover with particle sizes at2.5,2.0,1.5,1.0and0.5cm were compared. The highest sugar recovery reached99.6%for glucanand67.0%for xylan at particle size of1.0and0.5cm, respectively, but the highestsugar conversion (100%for glucan and83%for xylan) was observed at particle sizeof2.5cm. Enzymatic hydrolysis rate and conversion of pretreated biomass obviouslyincreased with increasing biomass particle size. With increase of biomass particle size,specific surface area significantly increased and crystallinity index apparentlydecreased. In studied extent of particle sizes, the utilization of larger biomass particleswould be desirable to achieve the high pretreatment efficiency and hence improvesubsequent enzymatic hydrolysis performance compared with the smaller ones.Sugar conversions and yields for wet stored biomass were obviously higher thanthose for dry stored biomass. Shredding reduced sugar conversions compared withnon-shredding, but increased sugar yields. Glucan conversion and glucose yield fornon-shredded wet stored biomass reached91.5%and87.6%, respectively. Data ofmicro-structure and crystallinity of biomass indicated that corn stover biomassmaintained the flexible and porous structure after wet storage, and hence led to thehigh permeability of corn stover biomass and the high efficiency of pretreatment andhydrolysis. Therefore, wet storage methods would be desirable for the conversion ofcorn stover biomass to fermentable sugars based on steam explosion pretreatment.