349161 Catalytic Deoxygenation of Pyrolysis Vapors for Biofuel Production

Monday, November 4, 2013
Grand Ballroom B (Hilton)
Julie Rorrer, Chemical Engineering, Arizona State University, Tempe, AZ and Matthew M. Yung, National Bioenergy Center, National Renewable Energy Laboratory, Golden, CO

An important step in the conversion of biomass to liquid hydrocarbon fuels is the efficient removal of oxygen compounds from pyrolysis vapors through catalytic deoxygenation reactions. In this investigation, catalysts were synthesized and tested for their deoxygenation ability in reactions with acetic acid, which serves as a model compound for pyrolysis of biomass. Catalysts on alumina (Al2O3) and zeolite (Zeolyst ZSM-5) supports were synthesized using incipient wetness impregnation to incorporate Ni and Cu into the structures.  Zeolite-supported catalysts with varying silica (SiO2) to alumina ratios (ZSM-5 SiO2:Al2O3; 80, 50, and 23) were also tested. The catalysts were characterized using XRD, SEM, EDS, and Temperature-Programmed Oxidation/Reduction. The catalysts were evaluated using transient temperature-programmed reactions (TP-Rxn) to assess the catalytic activity over a temperature range of 200 °C - 600°C, and using temperature programmed oxidation and reduction to determine catalyst deactivation. The catalysts which achieved the highest levels of deoxygenation in terms of selectivity towards carbon dioxide were the alumina supported catalysts and the low acidity (high SiO2:Al2O3) zeolite-supported catalysts. The addition of 5 wt% Ni into the catalysts increased selectivity towards decarboxylation, and increased the temperature range for which CO2 and CH4 are formed. The addition of 5 wt% Cu into the catalysts also increased selectivity towards CO2 and CH4 and broadened the range of higher temperatures at which selectivity towards CO2 is high. This investigation has identified trends with respect to metal addition and catalyst acidity that have the potential to improve deoxygenation of pyrolysis vapors.

Extended Abstract: File Uploaded