New insight on competitive reactions during deep HDS of FCC gasoline

• Published in: Applied catalysis. A, General Vol. 352; no. 1; pp. 114 - 123
• Main Authors: Dos Santos, N., Dulot, H., Marchal, N., Vrinat, M.
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier B.V 15.01.2009; Elsevier
• Subjects: 3MT; Catalysis; Chemical Sciences; Chemistry; CoMo/Al 2O 3; Exact sciences and technology; General and physical chemistry; H 2S effect; Hexene; Selectivity; Surface physical chemistry; Theory of reactions, general kinetics. Catalysis. Nomenclature, chemical documentation, computer chemistry; CoMo/Al 2O 3; 3MT; Selectivity; Hexene; H 2S effect; Sulfur compounds; Binary compound; Recombination; Active site; Purity; Hydrogen sulfides; Hydrogenation; Thermodynamics; Model compound; Inhibition; Chemical reactivity; H2S effect; Aluminium oxide; Thiol; CoMo/Al2O3; Competitive reaction; Heptane; Operating conditions; Heterogeneous catalysis; Olefin; Adsorption; Gasoline; Fuel; Kinetics; Alumina; Ethylenic compound; Hydrodesulfurization
• ISSN: 0926-860X; 1873-3875
• DOI: 10.1016/j.apcata.2008.09.035

In order to satisfy requests for high purity fuel, sulfur compounds have to be removed selectively from FCC gasoline with a minimum of olefins hydrogenation and recombination between olefins and H 2S (product of hydrodesulfurization) to form thiols. Competition between hydrodesulfurization (HDS) and olefin hydrogenation (HYD) is truly a non-trivial subject. In this study, the impact of H 2S on reactivity and selectivity has been studied for model compounds (3-methylthiophene and 1-hexene in heptane) under operating conditions allowing kinetic studies. Formation of C 6-thiols appears to be under thermodynamic control. Inhibition of H 2S on both HDS and HYD reactions has been demonstrated. Moreover, inhibition of olefins on HDS and of 3MT on hydrogenation have been observed. This competition between HYD and HDS reactions is an argument in favor of an adsorption of both olefin and sulfur compounds on the same active sites. In this study, impact of H 2S on reactivity and selectivity has been studied for 3-methylthiophene and 1-hexene in heptane. Formation of C6-thiols appears to be under thermodynamic control. Inhibition of H 2S on HDS and HYD reactions has been shown. Moreover, inhibition action of olefins on HDS and of 3MT on hydrogenation have been observed. ▪