Fast pyrolysis of soybean hulls: analysis of bio-oil produced in a fluidized bed reactor and of vapor obtained in analytical pyrolysis

This research involved an investigation into the composition both of vapors produced in the analytical pyrolysis of soybean hulls and of the bio-oil produced in the fast pyrolysis of soybean hulls in a fluidized bed reactor. The reaction temperatures were 450, 550, 650 and 750 °C for analytical pyrolysis and 550 °C for the fluidized bed reactor. Product compositions were analyzed using a gas chromatograph coupled to a mass spectrometer. The main objectives of this work were to evaluate the chemical potential of the produced bio-oil and to study the extent and the effects of secondary reactions that occur in the fluidized bed pyrolysis apparatus. The bio-oil proved to be a complex mixture; rich in phenols, cyclopentene derivatives and tetradecane. The main compounds identified in the vapor were 1,3-pentadiene, acetic acid and tetradecane. The differences between the composition of bio-oil and vapor are probably due to the occurrence of secondary reactions, the distinct heating rates applied during analytical pyrolysis and in the fast pyrolysis pilot plant, and the vapor condensing process in the pyrolysis pilot unit.