High-Solids Process for the Pretreatment of Lignocellulosic Feedstock in Bioethanol Production

This paper describes a high-solids (40-50% solids) pretreatment process that can be used to produce ethanol from lignocellulosic feedstock. A 130-L reactor, designed for processing slurries containing 30-50% solids, was used to demonstrate the process using dilute sulfuric acid. This pilot study showed that the proposed high-solids process is a promising approach to biomass pretreatment for thefollowing reasons: 1) a high degree of xylan hydrolysis with relatively low furfural formation; 2) lower acid consumption on a unit dry weight of biomass; and 3) lower costs due to reductions in heating energy and water usage. The resultant pretreated biomass shows good enzymatic digestibility and fermentability, and it is therefore a suitable substrate in the context of bioethanol production.Furthermore, this process can be easily scaled up because a commercial-scale version of this reactor is used in the cellulose-derivatives industry: this is a vitally important aspect since the scale-up of many bench-scale prototypes is nontrivial.