Rapid Pyrolysis of Olive Residue. 1. Effect of Heat and Mass Transfer Limitations on Product Yields and Bio-oil Compositions

In this study, the aim was to obtain high bio-oil yields in a fixed bed tubular reactor at various pyrolysis temperatures, reaction times, sweeping gas velocities, particle sizes, and heating rates. In order to improve heat and mass transfer, a stainless steel basket was used. The raw material, olive residue, was placed into the reactor in two different ways: directly and with a stainless steel mesh basket. It was proved that employment of the basket provided an effective heat transfer between the sample and reactor wall. As a consequence, higher volatile yields were observed. The maximum oil yield was achieved as 46.72% with a particle size of 0.85 < D p < 0.45 mm, heating rate of 500 °C min - 1, pyrolysis temperature of 500 °C, and sweeping gas flow rate of 400 cm 3 min - 1 . It was concluded that reducing the residence time of evolved volatiles, minimizing the particle size, increasing the heating rate at a pyrolysis temperature of 500 °C, and improving the contact surface of raw material with the reactor wall caused enhancement of mass and heat transfer through the system. Compositions of bio-oils were determined in detail with various chromatographic and spectroscopic methods. These results show that the composition of bio-oil is quite similar to that of crude oil.