Initial evaluation of simple mass transfer models to describe hemicellulose hydrolysis in corn stover

The uncatalyzed hydrolysis and removal of xylan from corn stover is markedly enhanced when operation is changed from batch to continuous flowthrough conditions, and the increase in hemicellulose removal with flow rate is inconsistent with predictions by widely used first-order kinetic models. Mass transfer or other physical effects could influence the hydrolysis rate, and two models reported in the literature for other applications were adapted to investigate whether incorporation of mass transfer into the kinetics could explain xylan removal in both batch and continuous flowthrough reactors on a more consistent basis. It was found that a simple leaching model and a pore diffusion/leaching model could describe batch and flowthrough data with accuracy similar to that of conventional batch models and could provide a more rational explanation for changes in performance with flow rate.