Master of Science in Chemical Engineering (MSChE)
A novel technology, a pulsed oscillating monolith reactor (POMR), was compared to a standard autoclave reactor for oxidative desulfurization (ODS) of a model diesel fuel. Two classes of catalysts, mesoporous Ti-MCM-41 and Pd on carbon, were used for ODS. The oxidants used were O2 and peroxide. The model diesel compound was 75 wt% alkanes, 24 wt% alkylaromatic, 0.95 wt% sulfur heterocycles and 0.05% nitrogen heterocycles. ODS reactions were conducted from 343-423 K and pressures from 1.0-1.3 MPa O2. The only component that was not oxidized was the alkane. The POMR showed promise; there was up to a factor of 20 enhancement in turnover frequency for alkylaromatics, up to a factor of 9 for sulfur heterocycles and up to 20 for nitrogen heterocycles. However, the POMR was no more selective and in some cases less selective when compared to runs performed in an autoclave. It was determined that the Ti-MCM-41 has a higher initial catalytic activity then supported Pd, but it deactivates more quickly due to the condensation of products on the surface and in the pores. It additionally had a higher selectivity than the carbon-supported Pd. The Ti-MCM-41 catalyst specifically did a better job of oxidizing dibenzothiophene, which is one of the most refractory sulfur compounds. There was no significant improvement from the substitution of benzoyl peroxide for O2 as oxidant. Neither the sulfur compound turnover frequencies nor the overall dibenzothiophene conversion were improved, when roughly equal amounts of oxidant were provided.
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Madrid, Andrew Marshall, "Catalytic Oxidative Desulfurization: A Comparison of Reactors" (2012). LSU Master's Theses. 2154.
Kerry M Dooley