Gasoline desulfurization by catalytic alkylation over silica-supported heteropolyacids: From model reaction to real feed conversion
Résumé
In FCC gasoline, the alkylation of sulfur compounds with olefins present in the feed, followed by a distillation to eliminate them, could be a good alternative for the desulfurization. Acidic materials (zeolites, supported acids) were screened for the alkylation of 3-methylthiophene (3MT) with 2-methyl-2-butene (2M2B), used as model reaction. Results showed that the silica-supported 12-phosphotungstic (HPW) and 12- silicotungstic (HSiW) acids are the best catalysts among zeolites and other supported acids. The performance of 40HPW/SiO2 was then studied in a real feed of FCC gasoline. The production of heavier sulfur compounds was obtained with high conversion, and this catalyst still showed some activity after 50 h of reaction, as compared to the silica-supported phosphoric acid (SPA-11), used as a reference. Moreover the deactivation could be reduced by increasing the reaction temperature.