Catalytic pyrolysis of torrefied olive stone for production of potential petrochemical alternatives

Bench-scale fluidized bed fast pyrolysis of as-received and torrefied residual olive stone (OS) was carried out at 500 °C in the presence or absence of a solid acid catalytic bed. Light to mild torrefaction conditions were investigated, with temperatures of 200, 225, and 250 °C, set in a bench-scale fluidized bed torrefier. Light torrefaction temperatures (200 and 225 °C) did not yield appreciable differences in the thermogravimetric pyrolysis studies, despite notable changes in mass and energy yield resulting from the influence of temperature difference. The mass and energy yields decreased from 91.1 to 74.0% and from 92.0 to 80.9%, respectively, moving from light to mild torrefaction. The higher heating value (HHV) increased linearly with an increase in torrefaction temperature, reaching a maximum of 22.1 MJ/kg at 250 °C, which was 9.7% greater than the as-received OS sample. A comparison was made between the influence of light and mild torrefaction on subsequent bench-scale pyrolysis experiments. In particular, the quality of bio-liquids for torrefaction coupled to fast pyrolysis shifted signifcantly towards the production of higher phenolic and aromatic derivatives that may find applications as potentaila drop-in alternative hydrocarbons. © 2022 The Authors. Biofuels, Bioproducts and Biorefining published by Society of Industrial Chemistry and John Wiley & Sons Ltd.