USE OF A DISPERSED MOLYBDENUM CATALYST AND MECHANISTIC STUDIES FOR UPGRADING EXTRA-HEAVY CRUDE-OIL USING METHANE AS SOURCE OF HYDROGEN

A dispersed molybdenum catalyst, derived from MoO2(acac)(2) (where aca c = acetylacetonate), was used for upgrading extra-heavy crude oil in the presence of methane as source of hydrogen. The experiments were ca rried out in a batch reactor at a final CH4 pressure of 11 MPa, 410 de grees C, for 1 h. An increase of 7 degrees in the API gravity, 16% of reduction in sulfur content, and 55% conversion of the >500 degrees C fraction with respect to the original crude was found. The catalyst wa s analyzed by XPS and EDAX from the coke isolated from the upgrading r eaction and it was confirmed that molybdenum is present as MoS2. By XP S and SIMS, mechanistic studies were carried out using MoS2 synthesize d on a pure molybdenum sheet. A mechanism for addition of the methane to crude oil is proposed which involves activation of CH4 by the MoS2 catalyst generating CHx and H4-x species on the catalyst surface (wher e x = 1, 2, or 3). The CHx moiety can be added to the hydrocarbon mole cules, forming methylated products. By carbon isotope ratio mass spect rometry analysis, labeled methane ((CH4)-C-13) was found to incorporat e into the crude oil (estimated value 0.01% w/w) giving conclusive evi dence on the involvement of CH4 in the heavy crude oil upgrading proce sses.