Co-torrefaction of corncob and waste cooking oil coupled with fast co-pyrolysis for bio-oil production

[Display omitted] •A new idea for hydrocarbon production by co-torrefaction coupled with co-pyrolysis.•Hydrogen in oil-bath co-torrefied corncob increased from 5.21 wt% to 6.12 wt%.•Average activation energy of oil-bath co-torrefied corncob was 164.29 kJ/mol.•Oil-bath co-torrefaction residual was more suitable for bio-oil production.•Torrefaction temperature has the greatest effect on pyrolysis bio-oil composition. Lignocellulosic biomass is a rich source of fixed renewable carbon and a promising alternative to fossil sources. However, low effective hydrogen to carbon ratio limits its applications. This work studied the influence of oil-bath co-torrefaction of corncob and waste cooking oil for co-pyrolysis. It was compared with dry torrefaction and hydrothermal wet torrefaction firstly. Residual of oil-bath co-torrefaction were the highest of 97.01 %. Oil-bath co-torrefaction could maximize hydrogen atoms retention in corncob, which has a positive significance for deoxygenation during pyrolysis. Oil-bath co-torrefaction could also reduce the average activation energy required for corncob decomposition, while it was increased with dry torrefaction. Oil-bath co-torrefaction coupled with co-pyrolysis was more suitable for hydrocarbon-rich bio-oil production. Oil-bath co-torrefaction temperature had the greatest influence on bio-oil composition. High pressure promoted formation of the CC double bond and degradation of lignin, which further promoted the formation of monocyclic aromatics in bio-oil.