Effect of Different Zeolite Supported Bifunctional Catalysts for Hydrodeoxygenation of Waste Wood Bio-oil

Abstract

Effects of various types of zeolite on the catalytic performance of hydrodeoxygenation (HDO) of bio-oil obtained from waste larch wood pyrolysis were investigated herein. Bifunctional catalysts were prepared via wet impregnation. The catalysts were characterized through XRD, BET, and SEM. Experimental results demonstrated that HDO enhanced the fuel properties of waste wood bio-oil, such as higher heating values (HHV) (20.4–28.3 MJ/kg) than bio-oil (13.7 MJ/kg). Water content (from 19.3 in bio-oil to 3.1–16.6 wt% in heavy oils), the total acid number (from 150 in bio-oil to 28–77 mg KOH/g oil in heavy oils), and viscosity (from 103 in bio-oil to 40–69 mm2/s in heavy oils) also improved post HDO. In our experiments, depending on the zeolite support, NiFe/HBeta exhibited a high Si/Al ratio of 38 with a high specific surface area (545.1 m2/g), and, based on the yield of heavy oil (18.3–18.9 wt%) and HHV (22.4–25.2 MJ/kg), its performance was not significantly affected by temperature and solvent concentration variations. In contrast, NiFe/zeolite Y, which had a low Si/Al ratio of 5.2, exhibited the highest improved quality for heavy oil at high temperature, with an HHV of 28.3 MJ/kg at 350 °C with 25 wt% of solvent.