Synthesis of alumina-nitrogen-doped carbon support for CoMo catalysts in hydrodesulfurization process

Abstract

More stringent environmental legislation imposes severe requirements to reduce the sulfur content in diesel to ultra-low levels with high efficient catalysts. In this paper, a series of CoMo/[email protected] catalysts were synthesized by combination of the chemical vapor deposition of nitrogen-doped carbon (NDC) using 1,10-phenanthroline and co-impregnation of Mo and Co active components. The optimal catalyst with additive of 25% 1,10-phenanthroline was screened by a series of property characterization and the hydrodesulfrization (HDS) active test. The amount of “CoMoS” active phase of the optimal CoMo/C3 catalyst increased 5.3% as compared with the CoMo/γ-Al2O3. The introduction of NDC improved the sulfidation degree of Mo by 21.8% as compared to the CoMo/γ-Al2O3 catalyst, which was beneficial to form more active sites. The HDS conversion of the NDC supported catalysts are higher than CoMo/γ-Al2O3 whether for the dibenzothiophene (DBT) or 4,6-dimethyl dibenzothiophene (4,6-DMDBT). Further hydroprocessing evaluation with Dagang diesel revealed that the CoMo/C3 catalyst possessed higher HDS property and the removal rate of DBTs in the diesel increased by 4%–11% as compared to the CoMo/γ-Al2O3 catalyst.