(198c) Effect of Bi-Functional Catalysts in Producing High Quality Liquid Fuels From Renewable Feedstocks

High quality liquid fuels were obtained by the in-situ catalytic treatment of pinewood pyrolysis vapors. An integrated reactor system, comprised of an auger reactor for the pyrolysis of pine wood chips and a packed bed reactor mounted on the top of auger for catalytic upgrading, was employed for the studies carried out at 450 ^oC and a WHSV of 10-12 h^-1. The catalysts used were HZSM5, 10 wt% Fe-ZSM5, 10 wt% Ni-ZSM5, HY, 10 wt% Fe-Y, Co-Mo/γ-Al₂O₃ and Ni-Mo/γ-Al₂O₃. All experiments were conducted for one hour at a biomass feed rate of approximately 10 g/min. The liquid and gas products were analyzed using GC-MS and GC-TCD-FID, respectively. Physical properties including water content, acid value, pH, viscosity, and elemental analysis of the upgraded bio-oils were measured. While the  fresh catalysts were characterized using BET, XRD,TPR, and TEM, coke deposits on the used catalysts were characterized using TGA.

Low liquid yields and high gas yields were observed in all the catalytic experiments. While all the catalysts successfully deoxygenated the pyrolytic vapors, product yields, product selectivity and the production of hydrocarbons varied significantly with the catalyst composition. Metal promoted zeolites were more effective as deoxygenation catalysts compared to the respective proton zeolites, with iron and nickel promoted HZSM5 catalysts producing the highest yields of phenolics and aromatic hydrocarbons, respectively. The oxygen contents and the acid values of the Fe and Ni promoted HZSM5 upgraded bio-oils were substantially lower. TG analysis showed that the metal promoted catalysts coked less than the unpromoted zeolites. Results indicate that the bi-functional catlysts are better deoxygenating catalysts than the unpromoted acidic catalysts.