MESOPOROUS MOLECULAR-SIEVE MCM-41 SUPPORTED CO-MO CATALYST FOR HYDRODESULFURIZATION OF PETROLEUM RESIDS

In this work, we explored the potential of mesoporous zeolite-supporte d Go-Mo catalyst for hydrodesulfurization of petroleum resids, atmosph eric and vacuum resids at 350-450 degrees C under 6.9 MPa of H-2 press ure. A mesoporous molecular sieve of MCM-41 type was synthesized; whic h has SiO2/Al2O3 ratio of about 41. MCM-41 supported Co-Mo catalyst wa s prepared by co-impregnation of Co(NO3)(2). 6H(2)O and (NH4)(6)Mo7O24 followed by calcination and sulfidation. Commercial Al2O3 supported C o-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 C o-Mo/Al2O3 for desulfurization of petroleum resids, It appears that th e pore size of the synthesized MCM-41 (28 Angstrom) is not large enoug h to convert large-sized molecules such as asphaltene present in the p etroleum resids. Removing asphaltene from the resid prior to HDS has b een found to improve the catalytic activity of Co-Mo/MCM-41(H). The us e of ATTM is not as effective as that of Co-Mo catalysts, but is bette r for conversions of >540 degrees C fraction as compared to noncatalyt ic runs at 400-450 degrees C. (C) 1998 Elsevier Science B.V. All right s reserved.