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

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" Effects of hydrogen sulfide, ammonia and water on catalytic hydrogenation of propylbenzene "
S. A. Ali

Document Type	:	Latin Dissertation
Language of Document	:	English
Record Number	:	1112660
Doc. No	:	TLpq303320335
Main Entry	:	S. A. Ali
Title & Author	:	Effects of hydrogen sulfide, ammonia and water on catalytic hydrogenation of propylbenzene\ S. A. Ali
College	:	King Fahd University of Petroleum and Minerals (Saudi Arabia)
Date	:	1984
student score	:	1984
Degree	:	M.S.
Page No	:	160
Abstract	:	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 375C under a hydrogen pressure of 1000 psig. with NiMo/Al2O3 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 330C, 42.8% at 350C and 36.4% at 375. 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. Comparision of oxide and sulfided forms of NiMo/Al2O3 catalyst showed that the hydrogenation activity enhances by 20-25 times due to sulfiding. All apparent activation energies were found to be in the range of 17-21 kcal/gmol.
Subject	:	Applied sciences
	:	Chemical engineering