Development of a multiphysics model of corn stover undergoing dilute-acid pretreatment in a steam-gun reactor

The pretreatment of lignocellulosic biomass is a complex process involving several chemical and physical phenomena, including mass and energy transfer, phase transition, and chemical reaction. While there are several existing mathematical models for both acidic and alkaline pretreatment of lignocellulosic biomass that were developed for the biofuels industry and separately for the paper and pulping industry, none of these models account for all of the above mentioned phenomena. We evaluate these existing models, and, by combining the relevant elements from these models, we propose a comprehensive mathematical model for steam-assisted dilute-acid pretreatment of lignocellulosic biomass that includes the effects of heat and mass transfer, the phase transition of steam to water, and the reaction and dissolution of structural carbohydrates. The model is developed specifically for the case of acid-impregnated biomass that is not fully saturated with aqueous solution, i.e. the pores within biomass particles are only partially filled with liquid at the start of pretreatment. We further performed model simulations using finite-element methods to numerically solve the partial differential equations, and the preliminary simulation results are compared to experimental data.