Valuable Biofuel Production via Pyrolysis Process of Olive Pomace over Alkali and Transition Metal Oxides Catalysts Supported on Activated Biochar

Abstract

Non-catalytic and catalytic pyrolysis of olive pomace as the second generation of biomass has been investigated for the production of valuable biofuels. Bio-oil from the pyrolysis of olive pomace has high amounts of oxygenated compounds, therefore in this study, NiO, CoO, MgO and CaO catalysts supported on the activated biochar were used to upgrade the bio-oil via the deoxygenation process. The results indicated that the maximum bio-oil production yield through noncatalytic process was 56 wt. % at a temperature of 500 °C, which mainly includes oxygenated compounds with content more than 90 wt. %. Production of hydrocarbons, ketones and aldehydes through catalytic pyrolysis process of olive pomace over alkali metal oxides catalysts confirm occurrence of the decarboxylation, decarbonylation, ketonization and aldol condensation reactions. MgO/biochar and CaO/biochar catalysts represented similar performance in the conversion of fatty acids, but the CaO/biochar deoxygenation performance was better than MgO/biochar catalyst. Catalytic pyrolysis investigations indicated that transition metal oxides (NiO and Co 3 O 4 / biochar) catalysts represent higher deoxygenation activity than alkali metal oxides catalysts.