2-07: Impact of moisture on the effective impregnation of corn stover for dilute acid pretreatment

Dilute acid pretreatment technology has shown to effectively hydrolyze xylan and improve the enzymatic saccharification of cellulose, resulting in high yields of fermentable sugars.  However, to ensure effective pretreatment, uniform distribution of catalyst is imperative. Past studies have demonstrated effective catalyst impregnation by soaking biomass in excess dilute acid. However, the scalability and commercial relevance of such a process is questionable. Thus, other impregnation methods, including spray and drip systems require investigation. Preliminary work suggests that a minimum liquid: solid ratio is required to effectively distribute catalyst after mixing and compression through a plug screw feeder.  The present study investigates the optimization of the liquid: solid ratio targeted during impregnation to maximize catalyst distribution and diffusion in corn stover when compressed in a plug screw feeder. NREL pilot scale equipment is used to ensure process relevance, and samples are analyzed for acid content. Impact of process changes on sugar yields from pretreatment and enzymatic hydrolysis are evaluated compared to dilute-acid soaked controls.