Improving hydrocarbons and phenols in bio-oil through catalytic pyrolysis of pine sawdust

The objective of this research was to develop low-cost metal-supported catalysts to improve the hydrocarbons, phenols, and phenolic compounds yield in the bio-oil. In this study, pyrolysis of pine sawdust was performed without a catalyst, with HZSM-5 catalyst and with Ni/HZSM-5 catalyst at temperatures of 400, 500, and 600 °C in a fixed bed reactor. The metal supported catalyst Ni/HZSM-5 was developed by wet impregnation method. The effects of temperatures and catalyst type on the yield and quality of the pyrolysis oil were investigated. The non-catalytic pyrolysis resulted in bio-oil yield of 37.4 wt% at 500 °C; however, HZSM-5 and Ni/HZSM-5 catalysts had a marginally lower yield of bio-oil (36.6 and 35.3 wt%, respectively) at 400 °C. The presence of catalysts improved the bio-oil viscosity by producing approximately more than 90% of light bio-oil while the remaining 10% was heavy bio-oil. Ni/HZSM-5 catalyst exhibited the best catalyst activity, with 80.2% and 49.7% yields of the desired compounds in heavy and light bio-oils respectively, while the bio-oil obtained without catalyst contained only 34.9% at 400 °C.