Upgrading of 4-methylanisole in a catalytic reactor with electric discharges: A novel approach to O-removal from bio-oils

Abstract

Lignocellulosic biomass is considered as a very promising alternative to replace fossil sources due to its abundance, consistency with environment and renewability. Conversion of lignin biomass to bio-oil by flash pyrolysis is considered recently due to its feasibility and economical profits. The produced bio-oil contains highly oxygenated compounds that require upgrading in order to be used as a fuel source. In this study, upgrading of 4-methylanisole as a model compound of lignin derived bio-oil was performed in a hybrid catalytic dielectric barrier discharge (DBD) plasma reactor under ambient temperature and atmospheric pressure. Different commercial catalysts including Pt–Cl, Ni–Mo, Co–Mo, Pt–Re and Ni supported on Al2O3 were packed between the two electrodes in the discharge zone. The effects of various catalysts on conversion of 4-methylanisole, discharge power (DP) to the rector, distribution of products and degree of deoxygenation were investigated. The highest 4-methylanisole conversion (98.7%) and deoxygenation degree (47%) were achieved in the presence of Pt–Cl/Al2O3 and Pt–Re/Al2O3 catalysts, respectively. The plasma catalysis system has a lower DP, electrode temperature and breakdown voltage compared to plasma alone. According to the results, the main products were 4-methylphenol, 2,4-dimethylphenol and p-xylene. The results indicated that the catalytic DBD plasma reactor is a promising tool for the upgrading of 4-methylanisole.