Attenuation of Catalyst Deactivation by Cofeeding Methanol for Enhancing the Valorisation of Crude Bio-oil

The catalytic transformation of crude bio-oil into hydrocarbons has been studied on a catalyst prepared based on a modified HZSM-5 zeolite. Previously, the bio-oil has been subjected to stabilization treatments to minimize pyrolytic lignin deposition on the catalyst and to attenuate deactivation. Cofeeding methanol (around 70 wt %) minimizes pyrolytic lignin deposition within and outside the catalyst particles, thereby increasing the viability of crude bio-oil upgrading. Given that the origin of catalyst deactivation is coke deposition within the particles, the nature of this coke has been studied by temperature-programmed oxidation. The coke is made up of (i) thermal coke (pyrolytic lignin formed mainly by polymerization of bio-oil phenolic components) and (ii) catalytic coke (formed in the HZSM-5 zeolite from bio-oil oxygenate compounds by acid sites). These two coke fractions have been quantified, and their combustion kinetics have been determined. Cofeeding methanol contributes to decreasing the conte...