Selective production of aromatic hydrocarbons from catalytic pyrolysis of biomass over Cu or Fe loaded mesoporous rod-like alumina

Abstract

The selective production of aromatic hydrocarbons from bio-oil derived from the fast pyrolysis of sunflower stalks over Cu or Fe-modified mesoporous rod-like alumina catalysts was investigated. Uniform mesoporous rod-like alumina with different pore sizes were successfully synthesized using a hydrothermal method with the assistance of Pluronic P123 surfactant. A high relative total hydrocarbon amount of about 59% in the upgraded bio-oil was obtained when pure mesoporous Al₂O₃ with a uniform pore size of 5.81 nm was used. Mesoporous Al₂O₃ with a larger pore size resulted in more polycyclic aromatic hydrocarbons (PAHs) such as indenes and naphthalenes being generated. Cu or Fe loaded Al₂O₃ with a loading amount in the range of 1–2.5 wt% showed a high selectivity towards monocyclic aromatic hydrocarbons (MAHs) such as benzene, toluene and xylenes (BTXs) over 80%. By using 2.5 wt% Cu/Al₂O₃-0.01, the highest relative total hydrocarbon amount reached 89%, which consisted of about 84% aromatic hydrocarbons and 4.9% aliphatic hydrocarbons. Both catalysts showed good catalytic stability and regeneration properties. A catalytic system with high effectiveness and long-term stability was expected to be obtained to convert the oxygenated compounds in bio-oil to high value-added hydrocarbons.