Mesoporous molecular sieve MCM-41 supported Co-Mo catalyst for hydrodesulfurization of dibenzothiophene in distillate fuels

摘要

The mesoporous aluminosilicate molecular sieve with MCM-41 type structure was synthesized using aluminum isopropoxide as the Al source. Supported Co-Mo/MCM-41 catalysts were prepared by co-impregnation of Co(NO_3)_2 centre dot 6H_2O and (NH_4)_6Mo_7O_(24) followed by calcination and sulfidation. For comparison, conventional Al_2O_3-supported sulfided Co-Mo catalysts were also prepared using the same procedure. These two types of catalysts were examined at two different metal loading level in hydrodesulfurization of a model fuel containing 3.5 wt% sulfur as dibenzothiophene in n-tridecane. At 350-375 deg C under higher H-2 pressure (6.9 MPa), sulfided Co-Mo/MCM-41 catalysts show higher hydrogenation and hydrocracking activities at both normal and high metal loading levels, whereas Co-Mo/Al_2O_3 catalysts show higher selectivity to desulfurization. Co-Mo/MCM-41 catalyst at high metal loading level is substantially active than the Co-Mo/Al_2O_3 catalysts.