(737e) In-Situ Catalytic Upgrading of Pinewood Pyrolysis Vapors: Effect of Process Variables

The main objective of this research effort was to produce high quality (i.e., deoxygenated, less acidic) bio-oil through in-situ catalytic modification (upgrading) of pine wood pyrolysis vapor. In-situ catalytic upgrading of pine wood pyrolysis vapors was performed using an integrated reactor set-up where fast pyrolysis of pine wood chips was carried out in an auger reactor followed by catalytic upgrading in a packed bed reactor mounted on the top of auger reactor. The pyrolysis process was carried out at 450 °C under a nitrogen atmosphere. The effects of process variables such as catalyst composition (γ-Al₂O₃, Si/Al, HY, HZSM-5), temperature and Weight Hourly Space Velocity (WHSV) were studied. The WHSV was varied by changing the biomass feed rate while holding the amount of catalyst constant. Compared to non-catalytic experiments, deoxygenated products increased over all the tested acid catalysts.  While Si/Al and γ-Al₂O₃ yielded higher amounts of liquid product, the zeolites (HZSM-5, HY) favored the formation of aromatic hydrocarbons and higher gaseous yield. The GC-MS results, elemental analysis, acid value and Karl-Fisher titration analysis showed that the liquid fuel was deoxygenated to the largest degree.  The largest concentrations of gasoline-range hydrocarbons were obtained using the HZSM5 catalyst at low WHSV (6 h^-1) and moderate reaction temperatures (370-400 ^oC).  The occurrence of deoxygenation could be noticed through the reduced oxygen content in the form of H₂O (significant increase in water yield), CO, CO₂.