Meltem DOĞAN, Timur DOĞU, Saliha KILIÇARSLAN ÇETİNYOKUŞ

İzobütan dehidrojenasyonu için reaksiyon hız ifadesinin geliştirilmesi ve membran reaktör modellemesi

Bu çalışmada, hidrotermal olarak sentezi gerçekleştirilen Cr-MCM-41 (%3 Cr kütlece) katalizörü üzerinde izobütan dehidrojenasyonu için reaksiyon hız ifadesi geliştirilmiştir. Reaksiyon hızı belirleme çalışmaları diferansiyel reaktör şartlarında, sabit katalizör miktarı (0,05g) üzerinden, farklı izobütan başlangıç konsantrasyonlarında (0,002-0,01mol/L) ve farklı sıcaklıklarda (723K-873K) gerçekleştirilmiştir. CrMCM-41 katalizörü üzerinde yürütülen reaksiyon için aktivasyon enerjisi 55 kJ/mol olarak belirlenmiştir. Ticari olarak temin edilen Pd membran reaktör sisteminde 823K ve 873K sıcaklıklarda izobütan dehidrojenasyonu incelenmiştir. Reaksiyon uygulamalarının gerçekleştirildiği membran reaktör sistemi modellenmiştir. Model denkliklerinin oluşturulmasında izotermal reaktör ve yatışkın durum kabulleri yapılmıştır. Model denkliklerinin çözümünde MATLAB R2011a/ODE45 programından yararlanılmıştır. 823K'de membran reaktörde deneysel belirlenen dönüşüm değerlerinin model sonuçları ile uyum gösterdiği tespit edilmiştir. 873K'de model sonuçları ile deneysel sonuçlar arasındaki farklılık ise membranın 873K'de yan reaksiyonlar için aktif hale gelmesi ile açıklanmıştır

Derivation of reaction rate expression for isobutane dehydrogenation and membrane reactor modelling

In this study, reaction rate expression for isobutane dehydrogenation was derivated on the Cr-MCM-41 catalyst (3% wt. Cr) synthesized by hydrothermal method. The study on derivation of reaction rate expression was performed under differential reactor conditions, with fixed amount of catalyst (0.05 g), at different initial concentration of isobutane (0.002-0.01mol / L) and at different temperatures (723K-873K). Activation energy for the reaction carried out over Cr-MCM-41 catalyst was determined as 55 kJ /mol. Isobutane dehydrogenation was investigated at 823K and 873K in a Pd membrane reactor obtained commercially. Isothermal reactor and the steady-state assumptions were made in derivation of model equations. MATLAB R2011 / ODE45 program was used to solve the model equations. It was predicted that there was a consistence between the conversion value determined from modelling and conversion obtained experimentally for reaction application at 823K. The difference between the experimental and the model results for reactor temperature of 873K was explained by activity of membrane for side reactions.

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Casanave D.K., Fiaty J.A., Dalmon M., Kinetics and mechanism studies of the catalytic dehydrogenation of isobutane on Platinum-Indium catalyst, Reaction Kinetics and the Development of Catalytic Processes, 367-374, 1999. 2.
Çetinyokuş Kılıçarslan,S., Reaction Mechanism Research for Isobutane Dehydrogenation, Journal of the Faculty of Engineering and Architecture of Gazi University, 31 (2), 221-229, 2016.
Yanping S., Trevor, C.B., Kinetics of isobutane dehydrogenation and cracking over HZSM-5 at low pressures, Journal of Catalysis, 194, 301-308, 2000.
Milas I., Nascimento M.A.C., The dehydrogenation and cracking reactions of isobutane over the ZSM-5 zeolite, Chemical Physics Letters, 373, 379-384, 2003.
Le Minh C., Brown T.C., Rate parameters from low- pressure dehydrogenation of isobutane over zeolite catalysts, Applied Catalysis A: General, 310, 145-154, 2006. and
Rashidi M., Nikazar Z., dehydrogenation propane and simultaneous isobutane on Pt-Sn-K/Al2O3 catalyst, Chemical Engineering Research and Design, 95, 239-247, 2015.
Çetinyokuş Kılıçarslan S., Doğan M., Doğu T., Synhthesis and Characterization of Ca-Cr-MCM-41 Catalysts for Isobutane Dehydrogenation, Journal of the Faculty of Engineering and Architecture of Gazi University, 29 (3), 459-467, 2014.
Ciavarella P., Casanave D., Moueddeba H., Miachon Fiaty S.K., Dalmona J.A., Isobutane dehydrogenation in a membrane reactor Influence of the operating conditions on the performance, Catalysis Today, 67, 177-184, 2001.
Illgen U., Schafer R., Noack M., Kölsch P., Külnle A., Caro dehydrogenation of iso-butane using an MFI zeolit membrane reactor, Catalysis Communications, 2, 339- 345, 2001. supporeted catalytic
Bergh J., van den, Gücüyener C., Gascon J., Kapteijn F., Isobutane dehydrogenation in a DD3R zeolite membrane reactor, Chemical Engineering Journal, 166 (1), 368-377, 2011.
Steintuch M., Dessau R.M., Obsevation modelling and optimization of yield, selectivity and activity during dehydrogenation of isobutane and propane in a Pd membrane reactor, Chemical Engineering Science, 51 (4), 535-547, 1996.
Liang W., Hughes R., The catalytic dehydrogenation of isobutane to isobutene in a palladium/silver composite membrane reactor, Catalysis Today, 104, 238-243, 2005.
Farsi M., Jahanmiri A., Rahimpour M.R., Optimal operating condition of membrane reactors to enhance isobutene production, Journal of Industrial and Engineering Chemistry, 18, 1676-1682, 2012. and hydrogen
Koutsonikolas D., Kaldis Sakellaropoulos G.P., Potential application of a microporous silica membrane reactor for cyclohexane dehydrogenation, International Journal of Hydrogen Energy, 37, 16302-16307, 2012. S., Zaspalis V.T.,
Samimi F., Kabiri A., Mirvakili S., Rahimpour M.R., Simultaneous dimethyl ether synthesis and decalin dehydrogenation in an optimized thermally coupled dual membrane reactor, Journal of Natural Gas Science and Engineering, 14, 77-90, 2013.
Abo-Ghander Nabeel S., Logist F., Grace John R., Van Impe Jan F.M., Elnashaie S.E.H., Said Lim, C. Jim, Heterogeneous modeling of an autothermal membrane reactor coupling dehydrogenation of ethylbenzene to styrene with hydrogenation of nitrobenzene to aniline: Fickian diffusion model, Chemical Engineering and Processing: Process Intensification, 77, 50-65, 2014.
Kilicarslan S., Dogan M., DoguT., Cr Incorporated MCM-41 Type Catalysts for Isobutane Dehydrogenation and Deactivation Mechanism, Ind. Eng. Chem. Res., 52, 3674-3682, 2013.
Çetinyokuş Kılıçarslan S., Doğan M., Doğu T., Contribution of Pd membrane to dehydrogenation of isobutane over a new mesoporous Cr/MCM-41 catalyst, Int. J. Chem. Reactor Eng., 14 (3), 727-736, 2016.
Raich, B.A., Foley, H.C., Supra-equilibrium conversion in palladium membrane reactors: Kinetic sensitivity and time dependence, Applied Catalysis A: General, 129, 167-188, 1995.
Vernikovskaya N.V., Savin I.G., Kashkin V.N., Pakhomov N.A., Ermakova A., Molchanov V.V., Nemykina E.I., Parahin O.A., Dehydrogenation of propane-isobutane mixture in a fluidized bed reactor over Cr2O3/Al2O3 catalyst: Experimental studies and mathematical modeling, Chemical Engineering Journal, 176-177, 158-164, 2011.
Airaksinen S.M.K., Harlin M.E., Krause A.O.I., Kinetic Modeling of Dehydrogenation of Isobutane on Chromia/Alumina Catalyst, Ind. Eng. Chem. Res., 41 (23), 5619-5626, 2002.
Sahebdelfar S., Bijani P.M., Saeedizada M., Zangeneh F.T., Ganji K., Modeling of adiabatic moving-bed reactor for dehydrogenation of isobutane to isobutene, Applied Catalysis A: General, 395, 107-113, 2011.