Dilute sulfuric acid hydrolysis of biomass for ethanol production

A series of pilot plant experiments have been conducted to compare the performance of a system utilizing two percolation reactors in series to a single reactor system. Although theoretically capable of producing higher glucose yields or concentrations, the two-reactor system concentrations were approximately the same and the yields were considerably lower than those from the single reactor study. An associated kinetics study found the glucose degradation kinetics to be accelerated by chromium ions, but this effect was greatly reduced in the presence of wood. The presence of metal surfaces also increased the rate of degradation even without large ion concentrations. The poor performance of the reactor system is proposed to be caused by intraparticle glucose diffusion effects and the catalytic effect on glucose degradation reactions of chromium ions from the corrosion of stainless steel by the acid. Strategies for reducing the effects of these phenomena on PBR performance are presented.