Mesoporous molecular sieve MCM-41 supported Co–Mo catalyst for hydrodesulfurization of petroleum resids

Abstract

In this work, we explored the potential of mesoporous zeolite-supported Co–Mo catalyst for hydrodesulfurization of petroleum resids, atmospheric and vacuum resids at 350–450°C under 6.9 MPa of H 2 pressure. A mesoporous molecular sieve of MCM-41 type was synthesized; which has SiO 2/Al 2O 3 ratio of about 41. MCM-41 supported Co–Mo catalyst was prepared by co-impregnation of Co(NO 3) 2·6H 2O and (NH 4) 6Mo 7O 24 followed by calcination and sulfidation. Commercial Al 2O 3 supported Co–Mo (criterion 344TL) and dispersed ammonium tetrathiomolybdate (ATTM) were also tested for comparison purposes. The results indicated that Co–Mo/MCM-41(H) is active for HDS, but is not as good as commercial Co–Mo/Al 2O 3 for desulfurization of petroleum resids. It appears that the pore size of the synthesized MCM-41 (28 Å) is not large enough to convert large-sized molecules such as asphaltene present in the petroleum resids. Removing asphaltene from the resid prior to HDS has been found to improve the catalytic activity of Co–Mo/MCM-41(H). The use of ATTM is not as effective as that of Co–Mo catalysts, but is better for conversions of >540°C fraction as compared to noncatalytic runs at 400–450°C.