New pilot plant capabilities for demonstrating biochemical-based technologies for advanced biofuel production from lignocellulosic biomass

The NREL/DOE biochemical pilot plant is used to develop and demonstrate new technologies for converting lignocellulosic biomass to fuels and chemicals. This facility supports both DOE and industrially funded projects requiring pilot-scale equipment to generate representative materials (e.g., pretreatment slurries) and to produce process-relevant research results. We will highlight new improvements and capabilities added to the facility in the last five years that enhance its ability to support the emerging biofuels industry. The pilot plant is used to perform applied R&D, usually with the goal of exploring process performance (pretreatment and enzymatic hydrolysis yields) or investigating key equipment/scale up issues (solid-liquid separation, aeration). For some problems, reliable and relevant results can only be obtained using pilot-scale equipment. Several recent examples of research conducted in the pilot plant will be discussed. We demonstrated that deacetylating biomass (removing acetyl groups through a mild alkaline treatment) prior to dilute-acid pretreatment improved cellulose enzymatic hydrolysis yields. Residence time distributions were measured in a continuous, horizontal screw-tube pretreatment reactor providing insight into mixing in these types of pretreatment devices, which allows us to develop fluid dynamic and kinetic models that can be used to increase sugar yields and reduce undesired product formation. Finally, recent research suggests that pre-impregnating biomass with acid prior to pretreatment improved conversion yields compared to yields achieved using an on-line acid impregnation technique, presumably due to limited acid/biomass contact time inherent in the latter process.