Effects of hydrogen sulfide, ammonia and water on catalytic hydrogenation of propylbenzene

(1984) Effects of hydrogen sulfide, ammonia and water on catalytic hydrogenation of propylbenzene. Masters thesis, King Fahd University of Petroleum and Minerals.


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A high-pressure reactor system for studying catalytic hydroprocessing reactions was constructed and tested. The autoclave was used as a liquid-phase batch slurry reactor for investigating the individual and simultaneous effects of hydrogen sulfide, ammonia and water on the kinetics of catalytic hydrogenation of propylbenzene. Experiments were carried out at 330, 350 and 375 °C under a hydrogen pressure of 1000 psig. With NiMo/A1₂0₃ commercial hydrotreating catalyst. The catalyst was used either in oxide form or after presulfiding it in the laboratory. The partial pressures of hydrogen sulfide, ammonia and water was kept at about 100 mm Hg. Each (for the experiments in which their presence was needed). About 1 wt% of propylbenzene was taken in n-hexadecane. Liquid samples were analysed by Gas Chromatography. Propylcyclohexane was the only product of propylbenzene hydrogenation. The hydrogenation of propylbenzene over both oxide and sulfided catalysts was observed to follow pseudo-first order kinetics in propylbenzene under all conditions studied. Results showed that due to the presence of hydrogen sulfide, the hydrogenation rate was reduced by 10-15%. Filling of sulfur-anion vacancies is postulated as the cause for this effect. In the presence of hydrogen sulfide and ammonia, the rate was inhibited by 44.7% at 330 ⁰C, 42.8% at 350° C and 36.4% at 375⁰C. This increase in inhibition is due to the competitive adsorption of highly basic ammonia on the acidic sites. Addition of water to hydrogen sulfide and ammonia does not influence the rate of hydrogenation. Comparison of oxide and sulfided forms of NiMo/A1₂0₃. In the above expression B₀, B₁, B₂, B₃ are function of I₁. To predict the behaviour of the system in presence of any two concentrations of I₁ and I₂, a new concept, interaction factor ψ is greter than unity and antagonism, for ψ less than unity. The inhibitory effect would be additive for equal to unity.

Item Type: Thesis (Masters)
Subjects: Chemical Engineering
Department: College of Chemicals and Materials > Chemical Engineering
Committee Advisor: Gultekin, Selahattin
Committee Members: Al-Saleh, Muhammad A. and Abdel-Aal, Hussein K.
Depositing User: Mr. Admin Admin
Date Deposited: 22 Jun 2008 13:47
Last Modified: 01 Nov 2019 13:50
URI: http://eprints.kfupm.edu.sa/id/eprint/9713