Reaction coupled with transport phenomena in oxidative coupling of methane:CFD modeling for single pellet

Authors

1 iran

2 tehran

Abstract

This study presents the phenomena occuring in small scale single-pellet for the oxidative coupling of methane where heat transfer plays an important role. Computational fluid dynamics (CFD) is used as a tool for obtaining detailed rate and temperature profiles through the porous catalytic pellet where reaction and diffusion are competing. Inter particle temperature and concentration gradients were taken into account by solving heat transfer coupled with continuity equations in the catalyst pellet. In the heat transfer equation the source term of energy due to high exothermic of reaction is considered. Subsequent to achieving this goal, two external programs are successfully implemented to CFD-code as kinetic and heat of reaction terms. This simulation results show the reaction is favorite for the beginning of the pellet and for downstream of the pellet domain the diffusion is predominates. The results of CFD simulation indicate that temperature variation within the catalyst pellet is < 1K due to the completion of exothermic oxidation reactions. Also, the results show that exothermic oxidation reactions occur before endothermic coupling reaction in the pellet length.

Keywords

References

 
 [1] یعقوبی، ن. (1387) تحقیقات روی گاز طبیعی در راستای اهداف سند چشم انداز، دومین سمپوزیوم بین المللی ایران توسعه یافته 1404، آبان.
[2] keller, G.E., Bhasin, M.M. (1982) “Synthesis of ethylene via oxidative coupling of methane”. Journal of Catalysis, Vol.73, pp. 9-19.
[3] Lane, G.S., Wolf, E.E. (1988) “Methane utilization by oxidative Coupling I. A study of reactions in the gas phase during the cofeeding of methane and oxygen”.Journal of Catalysis, Vol.113, pp. 144-163.
[4] Miro, E.E., Santamaria, J. M., Wolf, E. E. (1990) “Oxidative Coupling of Methane on Alkali Metal-Promoted Nickel Titanate”.Journal of Catalysis, Vol. 124, pp. 465-476.
[5] Hoebnik, J. M. B. J., Couwenberg, P. M., Marin G. B. (1994) “Fixed bed reactor design for gas phase change reactions catalysed by solids: The oxidative coupling of methane”. Chemical Engineering Science, Vol. 49, pp. 5453-5463.
[6]Tye, C.T.,  Mohamed, A.R., Bhatia,  S.( 2002) “Modeling of catalytic reactor for oxidative coupling of methane using La2O3/CaO catalyst”. Chemical Engineering Journal, Vol.  87, pp. 49-59.
[7] Yaghobi, N., Ghoreishy, M.H. R. (2008) “Oxidative coupling of methane in a fixed bed reactor over perovskite catalyst: A simulation study using experimental kinetic model”. Journal of Natural Gas Chemistry, Vol. 17, pp.  8-16.
[8] Yaghobi, N., Ghoreishy, M.H. R. (2009) “Modeling the oxidative coupling of methane: Heterogeneous chemistry coupled with 3D flow field simulation”. Journal of Natural Gas Chemistry, Vol. 18, pp. 39-44.
[9] Seyednejadian, S.,Yaghobi, N., Maghrebi, R., Vafajoo L. (2011) “CFD Modeling of Reaction and Mass Transfer through a Single Pellet: Catalytic Oxidative Coupling of Methane”. Journal of Natural Gas Chemistry, Vol. 20, pp. 356-363.
 
[10] Blazek, J. (2001) “Computational fluid dynamics: Principles and application”. Amsterdam, New York, Elsevier.
[11] Calis, H.P.A., Romkes, S., Dautzenberg, F.M., Van den Bleek, C.M. (2001) “First International Conference on Structured Catalysts and Reactors”. Delft, The Netherlands.
[12] Canu, P., Vecchi, S. (2002) “CFD Simulation of reactive flows: Catalytic combustion in a monolith”. AIChE Journal, Vol.48, pp.2921-2935.
 
[13] Dixon, A., Nejemeisland, M., Stitt, E.H. (2003) “CFD simulation of reaction and heat transfer near the wall of a fixed bed”. International journal of Chemical reactor Engineering, Vol.1, article 22.
 
[14] Nejemeisland, M., Dixon, A.G., Stitt, E.H.  (2004) “Catalyst design by CFD for heat transfer and reaction in steam reforming”. Chemical Engineering Science, Vol. 59, pp.5189-5191.
 
[15] Quiceno, R.,   Perez-Ramirez,  J., Warnatz, J., Deutschmann, O. (2007) “  Rational modeling of the CPO of methane over platinum gauze Elementry gas-phase and surface mechanisms coupled with flow simulations”. Catalysis Today, Vol.119, pp.311-316.
 
[16] Yi, Ch., zhu, J. (2008) “Hydrodynamics and scale up of liquid-solid circulating fluidized beds: similitude method vs. CFD”. Chemical Engineering Science, Vol. 63 pp. 3201-3211.
 
[17] Yaghobi, N., Mirzadeh, H., Bagherzadeh, E. (2001) “Conversion process of natural gas to ethylene”. 3rd Iran petrochemical Forum, pp. 245-256.
[18] یعقوبی، ن.، میرزاده، ح.، اسلامی منش، و.، پژوهشگاه پلیمر و پتروشیمی ایران. ساخت کاتاتست آزمایش تغیین پارامتر های کارایی کاتالیست های فرایند جفت شدن اکسایشی متان . ثبت اختراع 14659، سری الف/ 82
 
 [19] Stansch, Z., Mleczko, L., Baerns, M. (1995) “Kinetics for oxidative coupling of methane process over La2O3/Ca-O catalyst”. Industrial and Engineering Chemistry Research, Vol. 36, pp. 2568–2579.
 [20] Kolaczkowski, S.T., Chao, R., Awdry, S., Smith, A. (2007) “Application of a CFD code (Fluent) to formulate models of catalytic gas phase reactions in porous catalyst pellets”. Chemical Engineering Research and Design, Vol. 85 (A11), pp. 1539-1552.
[21] FLUENT 6.3 copyright FLUENT Inc. (2006).
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Journal of Modeling in Engineering
Volume 12, Issue 39
December 2014
Pages 123-141

Files

History

  • Receive Date: 28 January 2017
  • Revise Date: 18 September 2017
  • Accept Date: 28 January 2017

Share

How to cite

Statistics