Effect of NiO Loading on the Catalytic Activity of Ni-Al2O3 Catalyst by Co-precipitation for Green Diesel Production

Abstract

This project studied the effect of nickel loading on Ni-Al₂O₃ catalyst with preparation by co-precipitation method. The amount of NiO was 0, 20, 40, 60, 80 and 100%wt. The catalysts were characterized by XRD, N₂ adsorption-desorption, TEM and SEM-EDS techniques. Then, the synthesized catalysts were activated with H₂ superior to test with deoxygenation of oleic acid in a batch reactor. The reaction was operated at a temperature of 310°C for 4 h using H₂ pressure of 40 bar and analyzed the product with gas chromatograph. The characterization results revealed that the presence of crystal phase of β-Ni(OH)₂ and Al(OH)₃ was obtained for non-activation Ni-Al₂O₃ catalyst synthesized by co-precipitation. The synthesized catalysts were mesoporous structures. Moreover, only 19%wt of Ni metal was detected on the alumina surface. The catalytic activities via deoxygenation were determined using Ni-Al₂O₃(R) catalyst activated with H₂. The 80Ni-Al₂O₃(R) catalyst provided 68% conversion of oleic acid with maximum C17 yield via decarbonylation and decarboxylation. 54% of C14-C18 yield as a green diesel was obtained at reaction time of 240 min. This was due to the 80Ni-Al₂O₃(R) catalyst was the highest Ni on the catalyst surface area, high NiO dispersion and high average pore size. While, 0Ni-Al₂O₃(R) catalyst could not be active for deoxygenation, this can be seen from the lowest hydrocarbon yield less than 1%.