Investigating the Possibility of Coke Formation in Midrex Reformer

Document Type : Research Paper

Authors

1 Chemical Engineering Department, Islamic Azad University

2 Petroleum University

3 Chemical Engineering Department, University of South California, USA

Abstract

For the production of synthesis gas utilized in Midrex direct reduction plants, catalytic steam/CO2 reforming of hydrocarbons in tubular reactor is commonly used. Owing to the high heat flux through the wall of reformer tube, the endothermic nature of reforming reactions, low mass velocity of feed gas and large tube diameter, the catalyst bed is exposed to the considerable axial and radial temperature gradients. These radial gradients of concentration and temperature may create local areas with potency of carbon formation. In this investigation, a two dimensional model is developed for simulating the operation of a Midrex reformer. In this model, a thermodynamic approach is used to recognize zones inside the reformer tubes in which the risk of carbon formation is high. The simulation results are in good agreement with available data of Mobarake Plant, in Esfahan, Iran. The results show that the first half of tubes, both in center and near the wall, is critical in point of view of carbon formation.

Keywords

References

مراجع
[1] Sadri M., Vakhshouri K. and Hashemi M. M. Y. M., “Coke Formation Possibility During the Production of Reducing Gas in Large Scale Direct Reduction Plant”, Ironmaking and Steelmaking, 34,1-7, 2007.
[2] Wagner E. S. and Froment G. F., “Steam Reforming Analyzed” Hydrocarbon Processing, pp. 73, 69-77, 1992.
[3] Soneck J. W., Froment G. F. and Fowles M. “Steam/CO2 Reforming of Methane. Carbon Filament Formation by the Boudouard Reaction and Gasification by CO2,By H2,and by Steam :Kinetic Study”, Ind. Eng. Chem. Res.,41, pp. 4252-4265, 2002.
[4] Farhadi F., Hashemi M. M. Y. M. and Babaheidari M. B.,˝Radiative models for the furnace side of a Bottom-fired Raformer”, Applied Thermal Enginieering, 25, pp. 2398-2411, 2005.
[5] Deken D., Devos J. C., Froment G. F., Steam Reforming of natural gas: Kinetics, Diffusional Influence and Reactor Design, Chem. rea. Eng., 1982, 196.
[6] Hyman M. H., Simulate Methane Reformer Reaction, Hydrocarbon, Processing, July, 1968,131-137.
[7] Gunn D. J., “Axial and Radial Dispersion in Fixed Beds”, Chem. Eng. Sci., 42, pp. 363-373, 1987.
[8] Borkink J., Westerterp K. R., “Influence of Tube and Particle Diameter on Heat Transfer in Packed Beds” AIChE J, 38, pp. 703-715, 1992.
[9] Ergun S., “Fluid Flow through Packed Beds”, Chem. Eng. Prog. pp. 48,89-94, 1952.
[10] Akers W. W. and camp D. P., “Kinetics of the Methane Steam Reaction”, AIChE J,,4, pp. 471-474, 1995.
[11] Singh C. P. P. and Saraf D. N, “Simulation of side-fired hydrocarbon reformers”, Ind.Eng. Chem. Process,18, pp. 1-7, 1979.
[12] Elnashaie S. S. E. H., solaman M. A., Al-Ubaid A. S. and Adris A., “On the Non-monotonic Behavior of Methane-Steam Reforming Kinetics”, Chem. Eng. Sci., 454,91-501, 1990.
[13] Froment, G. F. and Bischoff, K. B., Chemical Reactor Analysis and Design ,2th Edition, Wiley publication,New York.,1999.
[14] Trambouze P., Landeghem H. V., and Weuquier J. P. Chemical Reactors, Gulf Publication Company, Texas, 1988.
[15] Daubert T. E. and Danner R. P., Design Institute for Physical Property Data,American Institute of Chemical Engineers, Hemispher Publishing,1991.
[16] Prausnitz J. M., Lichtenthaler R.N. and Azevedo E.G.D., Molecular Thermodynamics of fluid phase equilibria, 3rd,Prentice Hall PTR, 1999.
[17] Filla M. “An Improved Rosler _type Flux Method for Radiative Heat Transfer in one dimensional Furnace”, Chem .Eng.Sci., 39, pp. 159-161, 1984.
Journal of Petroleum Research
Volume 22, Issue 70 - Serial Number 70
July and August 2012
Pages 13-23

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