The Effect of Alkali Metal Promoters on the Stability and Coke Formation of Platinum-Based Propane Dehydrogenation Catalysts: A Kinetic Study

Document Type : Research Article

Authors

1 Department of Chemistry, Science and Research Branch, Islamic Azad University, Tehran, I.R. IRAN

2 Catalyst Research Group, Petrochemical Research and Technology Company, National Petrochemical Company, P.O. Box 14358-84711 Tehran, I.R. IRAN

Abstract

The kinetics of catalyst deactivation and coke formation during dehydrogenation of propane over supported Pt–based catalysts and, in particular, the effect of alkali metal promoters on catalyst activity and stability were studied. The analysis of propane conversion data showed that there is an optimum level of alkali metal promoter loading for both catalyst activity and stability.A model based on individual site poisoning was proposed for coke deposition kinetics. The model showed fair fits for coke formation data with time on stream. While the rate constant of coke formation was slightly affected by loading of Na as the neutralizing promoter, the ultimate coke amount was strongly dependent on the Na loading. It was found that coke formation sites should be different from active sites for the main reaction.  

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[1] Rostrup-Nielsen J.R., Industrial Relevance of Coking, Catal. Today, 232, p. 37 (1997).
[2] Bartholomew, C.H., Mechanisms of Catalyst Deactivation, Appl. Catal., A: General, 17, p. 212 (2001).
[3] Forzatti P., Lietti L., Catalyst Deactivation, Catal. Today, 165, p. 52 (1999).
[4] Sahebdelfar S., Kazemeini M., Khorasheh F., Badakhshan, A., Deactivation Behavior of the Catalyst in Solid Acid Catalyzed Alkylation: Effect of Pore Mouth Plugging, Chem. Eng. Sci,.3611, p. 57 (2002).
[5] Moulijn J.A., van Diepen A.E., Kapteijn F., Catalyst Deactivation: Is It Predictable? What to Do?, Appl. Catal., A: General, 3, p. 212 (2004).
[6] Bhasin M.M., Mc. Cain J.H., Vora B.V., Imai T., Pujado R.R., Dehydrogenation and Oxydehydrogenation of Paraffins to Olefins to Plefins, Appl. Catal,. A: General, 397, p. 221 (2001).
[7] Tahriri Zangeneh F., Sahebdelfar S., Effect of Addition of Different Promoters on the Performance of Pt–Sn–K/Al2O3 Catalyst in the Propane Dehydrogenation, IJChE, 8(3), p. 48 (2011).
[8] Vaezifar S., Faghihian H., Kamali M., Dehydrogenation of Isobutane over Nanoparticles of Pt/Sn Alloy on Pt/Sn/Na–Y Catalyst: the Effect of Tin Precursor on the Catalyst Behavior, Iran. J. Chem. Chem. Eng., 28(1), p. 23 (2009).
[9] Praserthdam P., Mongkhonsi T., Kunatippapong S., Jaikaew B., Lim N., Determination of Coke Deposition on Metal Active Ssites of Propane Dehydrogenation Catalysts, Studies in Surface Science and Catalysis, Stud. Surf. Sci. Catal., 153, p. 111 (1997).
[10] He S., Sun C., Bai Z., Dai X., Wang B., Dehydrogenation of Long Chain Paraffins over Supported Pt-Sn-K/Al2O3 Catalysts: A Study of the Alumina Support Effect, Appl. Catal., A: General, 88, p. 356 (2009).
[11] Casella M.L., Siri G.J., Santori G.F., Ferreti O.A., Ramirez-Corredores M.M., Surface Characterization of Li-Modified Platinum/Tin Catalysts for Isobutane Dehydrogenation, Langmuir, 5639, p. 16 (2000).
[12] Zhang Y., Zhou Y., Qiu Anding., Wang Y., Xu Y., Wu P., Effect of Na Addition on Catalytic Performance of PtSn/ZSM–5 Catalyst for Propane Dehydrogenation, Acta Phys. Chim. Sin., 22(6), p. 672 (2006).
[13] He S., Lai Y., Bi W., Yang X., Rong X., Sun C., Effect of K Promoter on the Performance of Pt–Sn–K/γ–Al2O3 Catalyst for n–Hexadecane Dehydrogenation, Chin. J. Catal., 31(4), p. 435 (2010).
[14] Resasco D.E., Dehydrogenation– heterogeneous, in: I.T. Horváth, (Ed.), “Encyclopedia of Catalysis, Vol. 3, Wiley, New York, (2003).
[15] Salmones J., Wang J.A., Galicia J.A., Aguilar-Rios, G., H2 Reduction Behaviors and Catalytic Performance of Bimetallic Tin-Modified Platinum Catalysts for Propane Dehydrogenation, J. Mol. Catal. A: Chem., 184, p. 203 (2002).
[16] Aguilar-Rios G., Salas P., Valenzuela M.A., Armendariz H., Wang J.A., Salmones, Propane Dehydrogenation Activity of Pt and Pt–Sn Catalysts Supported on Magnesium Aluminate: Influence of Steam and Hydrogen, Catal. Lett., 60, p. 21 (1999).
[17] Jiafeng Y., Qingjie G., Wen F., Hengyong X., Enhanced Performance of Ca-Doped Pt/g-Al2O3 Catalyst for Cyclohexane Dehydrogenation, Int. J. Hydrogen Energy, 36, p. 11536 (2011).
[18] Moghimpour Bijani P., Sahebdelfar S., Modeling of a Radial-Flow Moving-Bed Reactor for Dehydrogenation of Isobutane, Kinetics and Catalysis, 49(4), p. 599 (2008).
[19] Voorhies A., Carbon Formation in Catalytic Cracking, Ind. Eng. Chem., 37, p. 318 (1945).
[20] Corella J., Monzón A., Deactivation and Coking Relations Between Activity, Concentration of Coke and Time–on–Stream for Different Mechanisms of Formation and Accumulation of coke, Ann. Quim., 205, p.84 (1988).
[21] Dumez F.J., Froment, Dehydrogenation of 1–Butene Into Butadiene-Kinetics, Catalyst Coking, and Reactor Design,  G. F., Ind. Eng. Chem. Proc. Des. Dev., 291, p. 15 (1976).
[22] Mohagheghi M., Bakeri G., Saeedizad M., Study of the Effect of External and Internal Diffusion on the Propane Dehydrogenation Reaction over Pt–Sn/Al2O3 Catalyst, Chem. Eng. Technol., 30(12), p. 1721 (2007).
[23] Duan Y., Zhou Y., Zhang Y., Sheng X., Xue M., Effect of Sodium Addition to PtSn/AlSBA–15 on the Catalytic Properties in Propane Dehydrogenation, Catal. Lett., 120, p. 141 (2011).
[24] Zhang S., Zhou Y., Zhang Y., Huang L., Effect of K Addition on Catalytic Performance of PtSn/ZSM–5 Catalyst for Propane Dehydrogenation, Catal. Lett., 76, 135 (2010).
[25] Bai L., Zhou Y., Zhang Y., Liu H., Sheng X., Effect of Mg Addition to. PtSnNa/ZSM–5 on the Catalytic Properties in Propane Dehydrogenation, Ind. Eng. Chem. Res., 48(22), p. 9885 (2009).
[26] Del Angel G., Bonilla A., Navarrete J., Figueroa E.G., Fierro J.L.G., The Inhibiting Effect of Lanthanum on the Formation of Benzene over PtSn/Al2O3 Reforming Catalysts, J. Catal., 257, p. 203 (2001).
[27] Liu J., Gao, X., Zhang T., Lin L., Thermoanalytical Studies of Carbon Deposition on Pt/Al2O3 and Pt–Sn/Al2O3 Catalysts for Dehydrogenation of Butane in the Presence of Hydrogen, Thermochim. Acta, 9, p. 179 (1991).
[28] Tahriri Zangeneh F., Mehrazma S., Sahebdelfar S., The Influence of Solvent on the Performance of Pt-Sn/θ–Al2O3 Propane Dehydrogenation Catalyst Prepared by Co-Impregnation Method, Fuel Process. Technol., 109, p. 118 (2013).