Ceria on alumina support for catalytic pyrolysis of Pavlova sp. microalgae to high-quality bio-oils

In this work, we report for the first time the in-situ catalytic pyrolysis of Pavlova sp. microalgae, which has been performed in a fixed-bed reactor in presence of Ce/Al₂O₃-based catalysts. The effects of pyrolysis parameters, such as temperature and catalyst were studied on the products yield distribution and bio-oil composition, among others. Results showed that all catalysts increased the bio-oil yield with respect to the non-catalytic runs and reduced the O/C ratio from 0.69 (Pavlova sp.) to 0.1–0.15, which is close to that of crude oil. In terms of bio-oil oxygen content, MgCe/Al₂O₃ presented the best performance with a reduction of more than 30%, from 14.1 to 9.8 wt%, of the oxygen concentration in comparison with thermal pyrolysis. However, NiCe/Al₂O₃ gave rise to the highest aliphatics/aromatics fractions. The elemental and gas analysis indicates that N was partially removed from the catalytic bio-oils in the gas phase in forms of NH₃ and HCN.