Hierarchical porous honeycomb NiCo/C catalyst for decarboxylation of fatty acids and upgrading of sludge bio-crude

Abstract

Honeycomb NiCo/C-Na catalyst featured with a micro-meso-macroporous structure is fabricated and shows a significantly higher catalytic activity for decarboxylation of fatty acid compared to a series of other carbon-based catalysts. A 100 % conversion of stearic acid and a C15-18 alkane total yield of 70 % is achieved at 280 °C for 3 h under 1 MPa H2 with heptadecane as the main product. NiCo/C-Na also achieves a complete conversion of monoglyceride into heptadecane when using edible oil as reactant. The catalyst is further evaluated for upgrading of sludge HTL bio-crude and proves to be highly efficient. The obtained upgraded biofuel exhibits a decreased viscosity and an increased density. Specifically, the higher heating value (HHV) increases to 47.32 MJ/kg. This result is attributed to the easier desorption of CO2, better H2 activation capacity and the unique hierarchical pore structure of the catalyst, which allows faster mass transfer and reaction rate.