Catalytic hydropyrolysis of microalgae: Influence of operating variables on the formation and composition of bio-oil

Catalytic hydropyrolysis of microalgae has been studied by using a batch reactor. Nine different heterogenous catalysts of Pd/C, Pt/C, Ru/C, Rh/C, CoMo/γ-Al₂O₃, Mo₂C, MoS₂, and activated carbon were screened. Mo₂C was identified as the most suitable catalyst. With Mo₂C catalyst, influence of reaction conditions on the yield and properties of the hydropyrolysis oil (HPO) was examined. Temperature was the most influential factor affecting the yield and quality of the HPO. Higher temperature will produce HPO with higher C and H content and lower N and O content but at the cost of lowering the yield of HPO. Mo₂C promoted the in situ deoxygenation and desulfurization of the HPO which has a HHVs varying between 35.3 and 39.3MJ/kg. The highest energy recovery of 87.5% was achieved. Thus, this work shows that the catalytic hydropyrolysis is an effective way to produce high quality bio-oil from microalgae.