Chinese Journal of Chemical Engineering | 2021
Production of aromatic hydrocarbons by co-cracking of bio-oil and ethanol over Ga2O3/HZSM-5 catalysts
Abstract
Abstract The catalytic cracking of bio-oil is important to produce aromatic hydrocarbons, which can partially replace gasoline or diesel to greatly reduce carbon emissions from transportation. To further promote the formation of aromatic hydrocarbons, this work studied the effects of the preparation method and the acid strength of Ga2O3/HZSM-5 on catalytic cracking of the bio-oil distilled fraction systematically. The preparation method of Ga2O3/HZSM-5 had an important effect on its catalytic activity: the Ga2O3/HZSM-5 prepared by physical mixing showed the low dispersion of active phases and poor pore structure, resulting in its insufficient activity and severe coke deposition; the Ga2O3/HZSM-5 prepared by precipitation exhibited the higher activity, while many polycyclic aromatic hydrocarbons unfavorable for the subsequent utilization were in the oil phase; the Ga2O3/HZSM-5 prepared by impregnation showed the highest activity and 35.5%(mass) selectivity of the oil phase, including 80.3% monocyclic aromatic hydrocarbons and 12.0% polycyclic aromatic hydrocarbons. The Bronsted acidity of Ga2O3/HZSM-5 decreased with Si/Al ratio, leading to the decline in reactant conversion, oil phase selectivity and quality. Meanwhile, the polymerization between monocyclic aromatic hydrocarbons and oxygenates was promoted to produce many polycyclic aromatic hydrocarbons and even coke, causing catalyst deactivation.