A Patent on Hydrodesulphurization Catalysts for Use in the Production of Ultra-low Sulfur Diesel (ULSD) Fuel
Selective Hydrodesulfurization of FCC Gasoline to Below 10 PPM Sulfur,
MX2015002230 (A)
Commonly, organic sulfur-containing compounds are present in gasoline fractions as mercaptans, heterocyclic compounds and disulfides. Generally, heavier fractions are significantly contaminated by sulfur-containing compounds, especially heterocycles. In fact, gasoline with high amounts of sulfur-containing heterocyclic compounds is hard to process via common methods. In common, desulfurizational hydrotreating occurs under severe operating conditions that, in turn, results in a significant octane penalty.
However, it is possible to use adsorption instead of hydrotreating. Still, the removal efficiency of this process is not significant enough since aromatic heterocyclic sulfur compounds adsorb in a same way as aromatic compounds of hydrocarbon matrix. Aromatic heterocyclic compounds that need to be removed by the processes include alkyl substituted thiophene, thiophenol, alkylthiophene and benzothiophene. Additionally, it is essentially to note mercaptans that are to be removed by the processes often contain from 2-10 carbon atoms. Aromatic heterocyclic compounds of the particular interest are thiophene, 2-methylthiophene, 3-methylthiophene, 2-ethylthiophene, benzothiophene and methylbenzothiophene, collectively termed “thiophenes.”.
The difference of the offered by authors catalyst is in its structure and composition. In fact, the authors offer to use the catalyst that includes Group VIII metals, such as cobalt, nickel, palladium, alone or in combination with other metals, such as molybdenum or tungsten, on a respectable support like alumina, silica-alumina, titania-zirconia. In addition, the catalysts may also contain components from Groups VB and VIB of the Periodic Table and mixtures thereof. Especially, catalysts that containing a Group VIB metal, like molybdenum, and a Group VIII metal, such as cobalt or nickel, are preferred. However, authors suggest that catalysts suitable for the hydrodesulfurization reaction need to include cobalt-molybdenum, nickel-molybdenum and nickel-tungsten alloys rather than pure nanoparticles of pure molybdenum supported by cobalt or nickel that are used at the present. As for support, it is possible to leave the alumina or silica-alumina that are common for the …
