Microalgae has been considered as one of the promising biomass for renewable energy application and plate form molecules production. Hydrothermal catalytic liquefaction of chlorella and the derived biocrude in situ upgrading provides a better approach for wet feed conversion under mild reaction conditions. Highly active SBA-15 supported metal oxides structured catalysts have been fabricated with dual step coating method. The modified SBA-15 catalysts were employed for the model compounds (palmitic acid, methyl palmitate, and glutamic acid) hydrothermal conversion in a biphasic mixture of tetralin and water. The effects of catalyst properties (support Si/Al ration and pore size distribution) to deoxygenation products distribution were intensively studied. The influence of reaction conditions (reaction temperature, reaction time, and solvents) to reactants conversion. The relation of the fatty acid methyl ester (FAME) adsorption and CO2 desorption on the catalysts, and the products distribution has been studied. The apparent kinetics and in situ DRIFT of FAME decarboxylation were elucidated to deduce the rate-limiting step (CO2 desorption from the catalyst) and deactivation mechanism. The desorption temperature of CO2 on the CuO-ZnO/SBA-15 catalyst declined to 255°C when glutamic acid was added, which confirmed the interaction of methyl palmitate and glutamic acid, and the amides were produced in the co-conversion. The synergistic effect of acid sites and basic sites on the catalyst prompted the fatty acids and FAME decarboxylation or decarbonylation under milder conditions. It provided the experimental and theoretical basis for model reactants highly efficient conversion on the certain active sites of the modified SBA-15 catalysts. The catalysts were used for chlorella hydrothermal liquefaction- in situ upgrading to tune the products distribution preference to hydrocarbons. Challenges and opportunities in converting fatty acids and amino acids in a biphasic mixture via various routes would be reviewed briefly.

Mesoporous catalyst for microalgae liquified biocrude upgrading: Kinetics and mechanism study

256th National Meeting (2018)

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