COMPARISON OF YELLOW-POPLAR PRETREATMENT BETWEEN NREL DIGESTER AND SUNDS HYDROLYZER

Single-stage cocurrent dilute acid pretreatments were carried out on y ellow poplar (Liriodendron tulipifera) sawdust using an as-installed a nd short residence time modified pilot-scale Sunds hydrolyzer and a 4- L bench-scale NREL digester (steam explosion reactor). Pretreatment co nditions for the Sunds hydrolyzer, installed in the NREL process devel opment unit (PDU), which operates at 1 t/d (bone-dry t) feed rate, spa nned the temperature range of 160-210 degrees C, 0.1-1.0% (w/w) sulfur ic acid, and 4-10-min residence times. The batch pretreatments of yell ow poplar sawdust in the bench-scale digester were carried out at 210 and 230 degrees C, 0.26% (w/w) sulfuric acid, and 1-, 3-, and 4-min re sidence times. The dilute acid prehydrolysis solubilized more than 90% of the hemicellulose, and increased the enzymatic digestibility of th e cellulose that remained in the solids. Compositional analysis of the pretreated solids and liquors and mass balance data show that the two pretreatment devices had similar pretreatment performance.