Catalytic pyrolysis of microalgal lipids to alternative aviation fuels: catalysts with hierarchical structure and metal oxide doping.

Alternative aviation fuel is a crucial strategy to realize CO₂ reduction for airline industry and catalytic pyrolysis is one of important processes to produce alternative aviation fuels. However, catalytic pyrolysis is still hindered by high production cost and deactivation of catalysts during catalytic conversion processes. In this study, composite catalysts Me-Y/MCM-41 (Me = La, Ce, and Ni) with hierarchical pores and metal oxide doping have been synthesized for catalytic pyrolysis of microalgal lipids to produce alternative aviation fuels. The hierarchically porous supports were prepared via the method of in situ growth of mesoporous materials on microporous zeolites. The characterization of as-synthesized catalysts indicated the presence of mesoporous and microporous phases in composite catalysts, and metal oxides were well dispersed on the surface of hierarchically porous supports with the doping amount of 7.7–11.5%. Catalytic activity of as-synthesized composite catalysts was also evaluated by Py-GC/MS using the feedstock of microalgal lipids. After catalytic pyrolysis, the selectivity of hydrocarbons in liquid biofuels significantly increased, especially for composite catalyst Ce-Y/MCM-41, while the composition of liquid biofuels was predominated by fatty acids in blank experiments without catalysts. Therefore, the main composition of liquid biofuels were alkanes, olefins, and aromatic hydrocarbons with high selectivity (above 70%) on kerosene-range products (C₈–C₁₆). This research provides necessary information about novel hierarchically porous composite catalysts for microalgae-based biorefinery and production of alternative aviation fuels by catalytic pyrolysis. [ABSTRACT FROM AUTHOR]