How Wood Chip Size Affects Pretreatment Effectiveness of Woody Biomass for Biological Processing
Woody biomass is particularly resistant to breakdown and must be size reduced to make pretreatment with steam, acid, or other chemicals effective. However, because mechanical size reduction of woody biomass can consume significant amounts of energy, it is important to understand how to minimize size reduction, while still realizing high sugar yields from the combined operations of pretreatment and enzymatic hydrolysis. Thus, this study focused on determining how sugar yields change with particle size. Downscaled composition analysis and enzymatic hydrolysis were applied to different sized wood chips and powder of Populus tremuloides to examine whether wood chips could perform similarly to powder. It was found that above a certain pretreatment severity range (R0=3.8), large wood chips could give higher enzymatic sugar yields, so that size reduction is not always required, thus saving energy. Furthermore, models were applied to better understand whether heat transfer affected pretreatment effectiveness and establish maximum dimensions for high sugar release.