Flash Pyrolysis of Oleaginous Biomass in a Fluidized-Bed Reactor

In this study, flash pyrolysis was performed using milled soybean as a model substrate to assess the production of liquid fuels from oleaginous biomass feedstocks. A laboratory-scale fluidized-bed flash pyrolysis reactor that allowed rapid heat transfer to the biomass along with short vapor residence time was designed and constructed. Pyrolysis was performed between 250 and 610 degrees C with a vapor residence time between 0.2 and 0.3 s. At 550 degrees C or higher, nearly 70% of the initial feed mass as well as feed carbon was recovered in bio-oil. In addition, 90% of the feedstock lipids were recovered in the bio-oil at these pyrolysis conditions. The high liquid products yields were attributed to (1) the low secondary degradation of bio-oils due to the short vapor residence time and (2) the high recovery of liquids in a novel dry ice packed-bed condenser that provided a high surface area for condensation/aggregation of dilute bio-oil vapors/aerosols that were entrained in the carrier gas. The bio-oil from this study had higher C and H content, higher calorific value, and lower oxygen and water content than bio-oil from wood. These results show that high-quality bio-oil at high yield can be obtained from flash pyrolysis of oleaginous feedstock.