Influence of reaction conditions on the hydrodeoxygenation of light components in bio-oil to long-chain alkanes over Ni/HZSM-5-γ-Al2O3

A modified gamma-Al2O3-supported nickel-based Ni/HZSM-5 catalyst prepared by the impregnation method was characterized by physical adsorption of N-2, X-ray diffraction, temperature-programmed desorption of ammonia, thermogravimetric analysis, and scanning electron microscopy. The influence of temperature, pressure, flow, and space velocity on the hydrodeoxygenation (HDO) of light components in bio-oil was studied, and a lifespan test was performed on the Ni/HZSM-5-gamma-Al2O3 catalyst. The results showed that at a reaction temperature of 380 degrees C, pressure of 2 MPa, flow rate of 380 ml min(-1), and mass space velocity of 0.78 h(-1), the hydrocarbon content of the upgraded oil was the highest, reaching 89.47%. Long-chain alkanes were the main hydrocarbons in the upgraded oil. The results of a lifespan experiment show the good stability of the Ni/HZSM-5-gamma-Al2O3 catalyst in the HDO of bio-oil over 5 h of reaction. The HDO reaction pathway of bio-oil mainly resulted in conversion into long-chain alkanes through a condensation reaction, a decarbonylation/decarboxylation reaction and hydrogenation. This study provides a reference for the preparation of high-quality liquid fuels from biomass.