Co-hydrotreatment of pyrolysis oil with coconut oil towards jet fuel-range hydrocarbons

Although fast pyrolysis is a mature technology, the upgrading of pyrolysis oil to drop-in transportation fuels remains a major challenge. Catalyst deactivation, formation of coke, and the removal of methoxyl groups in the form of CH 4 are the key limitations identified. Furthermore, the resulting cuts are typically rich in aromatics, while stringent fuel specifications add additional difficulties to pyrolysis oil hydroprocessing. As a result, co-hydrotreatment approaches with lipids and other hydrocarbons have gained attention. However, prior studies have reported limited selectivity toward jet fuel-range hydrocarbons. In this study, co-hydrotreatment of pyrolysis oil (PyOil) with coconut oil (CNO), a lipid rich in medium-chain fatty acids that are more aligned with jet fuel carbon range distribution, was investigated as a strategy to maximize jet fuel cut. Co-hydrotreatment results showed that increasing CNO content led to a linear increase (R 2 = 0.99) in upgraded oil yield, substantial reductions in coke, gas, and water formation, and lower hydrogen consumption of approximately 50% compared to pure PyOil. With CNO blending, upgraded oils revealed a marked shift in hydrocarbon distribution toward n-paraffinic, jet fuel-range hydrocarbons, accompanied by a significant reduction in oxygenated compounds. Jet fuel-range hydrocarbon selectivity increased from 28% for pure PyOil to over 80% for CNO-rich blends, with jet fuel hydrocarbon yields increasing by up to almost eightfold relative to pure PyOil. Specifically, the obtained jet fuel hydrocarbon yields (on a feed wt% basis) for the different blends were 6.31% (100:0), 38.04% (50:50), 52.18% (30:70), and 68.43% (0:100). All jet fuel distillation cuts exhibited high calorific value (up to ∼48 MJ/kg). Although upgraded oil yield improvements were largely additive, the compositional shifts induced by CNO blending were highly favorable for sustainable aviation fuel (SAF) production. These results demonstrate that medium-chain fatty acid–rich CNO provides an effective co-feed strategy to enhance the jet-fuel relevance of biomass-derived pyrolysis oils.