Alkaline Pretreatment of Corn Stover: Pilot-Scale Fractionation, Stream Characterization, and Bench-Scale Enzymatic Hydrolysis

Alkaline pretreatment is a process by which lignocellulosic biomass is separated into a carbohydrate rich solid phase and a lignin rich liquor phase using a caustic aqueous solution. Previous bench scale work has shown that the efficacy of the alkaline pretreatment depends upon contact time, temperature of the solution, severity, and constitution of the biomass. A three factor, two level central composite experimental design with triplicate runs at the center point was conducted at the pilot scale to determine the relationship of pretreatment NaOH loading, temperature, and AQ loading on solids solubilization and component yields.  Alkaline pretreatment was performed in a 130 L, jacketed, horizontal vessel with agitation at 15 rpm for 30 minutes at 10% (w/w) TS.  In addition to the 17 alkaline pretreatment runs conducted within the central composite experimental design, a wash step was applied to five additional pretreatment runs to examine the effect of washing on lignin removal, alkaline pretreated insoluble solids composition, and enzymatic hydrolysis yields. This presentation will address the procedures for scaling this process to pilot scale as well as resulting pretreatment yields and enzymatic hydrolysis results.