Liquefaction of Lignocellulose

The liquefaction of biomass materials is a process where particulate wood, corn stover, sugarcane bagasse and other forms of lignocellulose feedstocks are converted to an aqueous suspension of solid materials that is suitable for further processing to fermentable sugars and biofuel materials. A number of reports have described the liquefaction of pretreated materials using either cellulose enzyme or an enzyme biomimetic (maleic acid). Our work has evolved to begin to examine the liquefaction of lignocellulosic substrates at 25% solids loading prior to pretreatment, since the ability to obtain pumpable slurries prior to pretreatment has significant benefits in equipment design and operating conditions for the pretreatment step itself. Challenges in obtaining pumpable slurries of biomass materials, either pre- or post-pretreatment include the shear thinning character of the slurry, mixing of the particulate biomass during the liquefaction process, and definition of operating conditions that make efficient use of the biocatalysts required for the liquefaction process. This paper presents an analysis of the insoluble particle characteristics that enable slurries to be obtained, and proposes a model for the liquefaction process that relates particle size, shape, and composition to the liquefaction process.