Improvement of Hydrodynamics Performance of Naphtha Catalytic Reforming Reactors Using CFD

Document Type: Research Note

Authors

Process Development & Control Group, Process Development & Equipment Technology Division, Research Institute of Petroleum Industry (RIPI), Tehran, I.R. IRAN

Abstract

Due to high applicability of the fixed bed catalytic naphtha reforming reactors, hydrodynamic features of this kind of reactors with radial flow pattern are improved in this work by utilising computational fluid dynamics technique. Effects of catalytic bed porosity, inlet flow rate and flow regime through the bed on the flow distribution within the system are investigated.It is found that the first reactor among three fixed bed reactors in series is working inappropriately. It is due to the effects of recirculating flow on the hydrodynamics. In addition, flow distribution at the end of each bed is discovered to be non-uniform. By applying computational fluid dynamics technique to the system and manipulating effective parameters, not only vortices are removed at the end of each bed, but also flow distribution through the first reactor is considerably improved. A new internal modification for all reactors is proposed, which allows reactors to become overloaded with the catalyst. Subsequently, inlet flow rate can rise by 10-15 per cent over its current value.

Keywords

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[1] Ranade V.V., "Computational Flow Modeling for Chemical Reactor Engineering", Academic Press, London (2002).
[2] Zafar Q., Gevert B., von Sivers M., Statistical Model for Benzene Prediction in Catalytic Reforming, Prepr. Pap. Am. Chem. Soc., Div. Fuel Chem., 48: 2-660 (2003).
[3] Boyas R.S., Froment G.F., Fundamental Kinetic Modeling of Catalytic Reforming, Ind. Eng. Chem. Res., 48: 1107-1119 (2009).
[4] Fazeli A., Fatemi Sh., Mahdavian M., Ghaee A., Mathematical Modeling of an Industrial Naphtha Reformer with Three Adiabatic Reactors in Series, Iran. J. Chem. Chem. Eng. (IJCCE), 28: 97 (2009).
[5] Fortuny A., Bengoa C., Font J., Castells F., Fabregat A., Water Pollution Abatement by Catalytic Wet Air Oxidation in a Trickle Bed Reactor, Catalysis Today., 53: 107-114 (1999).
[6] Froment G.B., Bischoff K.B., "Chemical Reactor Analysis and Design", Wiley & Sons, New York (1990).
[7] Raskin A.Y., Sokolinskii Y.A, Mukosei V.I., Aerov M.E., Theor. Found. Chem. Techn [in Russian]., 2: 220 (1968).
[8] Panahandeh M.R., Fathikaljahi J., Taheri M., Steady-State Modeling and Simulation of an Axial-Radial Ammonia Synthesis Reactor, Chem. Eng. Technol., 26: 666-671 (2003).
[9] Liang K.M., Guo H.Y., Pan S.W., A study on Naphtha Catalytic Reforming Reactor Simulation and Analysis, J. Zhejiang. Univ. Sci., 6B: 590-596 (2005).
[10] Hlavacek V., Kubicek M., Modeling of Chemical Reactors-XXV: Cylindrical and Spherical Reactor with Radial Flow, Chem. Eng. Sci., 27: 177-186 (1972).
[11] Calo J.M., Cell Model Studies of Radial Flow, Fixed Bed Reactors, ACS. Symp. Ser., 65, 550 (1978).
[12] Genkin V.S., Dil’man V.V., Sergeev S.P., The Distribution of a Gas Streem Over a Radial Contact Apparatuos,  Int. Chem. Eng., 13: 24-     (1973).
[14] Chang H.C., Calo J.M., An Analysis of Radial Flow Packed Bed Reactor, ACS Symp. Ser., 168, 305 (1981).
[15] Lobanov E.L., Skipin Y.L., Increasing the Operating Efficiency of Radial Reactors in Reforming, Chem. Tech. Fuels Oil., 22: 275-    (1986).
[16] Nooy F.M., Dense Loading, Oil & Gas Journal., 82: 152-    (1984).
[17] Song X., Wang Z., Jin Y., Gong M., Investigations on Hydrodynamics of Radial Flow Moving Bed Reactors, Chem. Eng. Technol., 16: 383-  (1993).
[18] Heggs P.J., Ellis D.I., The Modeling of Fluid-Flow Distribution in Aannular Packed Beds, Gas Sep. & Pur., 8:257-  (1994).
[19] Bolton G.T., Hooper C.W., Mann R., Stitt E.H., Flow Distribution Measurement in a Radial Flow Fixed Bed Reactor Using Electrical Resistance Tomography, "Proceedings of 17th International Symp. On Chem. Eng.", Hong Kong, (2002).
[20] Ranade V.V., Improve Reactor via CFD, Chem. Eng. (An Indian J)., 104: 96- (1997).
[21] Mohammadikhah R., Ziyari A., Behjat Y., Ahmadi-Marvast M., Ayazi M., Nikbakht M., Removing Mal-Distribution Through a Radial-Flow Fixed Bed Reactor using CFD, "Proceedings of 6th Int. Chem. Eng. Cong.", Iran (2009).
[22] Mohammadikhah R., Behjat Y., Ahmadi-Marvast M., Nikbakht M., Ganji H., CFD Application in Capacity Enhancement of Naphtha Catalytic Reforming Unit of Tehran Refinery, "Proceedings of 14th Int. Oil. Gas. Petrochem. Cong.", Iran (2010).
[23] Mohammadikhah R., Ganji H., Ahmadi-Marvast M., Zahedi Abghari S., Turbulence Model Inspection for Hydrodynamics of Naphtha Catalytic Reactors, "Proceedings of 7th Int. Chem. Eng. Cong.", Iran (2011).
[24] Mohammadikhah R., Zahedi Abghari S., Ahmadi-Marvast M., Ganji H., Simulation of Hydrodynamic and Heat Transfer Phenomena in Catalytic Reforming Reactors via CFD, Petroleum Science & Technology journal [In Persion], 73: 25-44 (2012).
[25] Mohammadikhah R., Zahedi Abghari S., Ahmadi-Marvast M., Ganji H., CFD Simulation of Catalytic Naphtha Reforming Process, "7th International Chemical Engineering Congress & Exihibition", 21-24 November, Kish Island, Iran, (2011).
[26] Carman P.C., Fluid Flow Through Granular Beds, Trans. Inst. Chem. Eng., 15: 150- (1937).
[27] Ergun S., Flow Through Packed Columns, Chem. Eng. Prog., 48: 89- (1952).
[28] Mehta D., Hawley M.C., Wall Effect in Packed Column, Ind. Eng. Chem. Proc. Des. Dev., 8: 280- (1969).
[30] Hosseini-Ashrafi M.E., Tuzun U., A Tomographic Study of Voidage Profiles in Axially Symmetric Granular flows, Chem. Eng. Sci., 48: 53- (1993).
[31] Zhang Z.P., Liu L.F., Yaun Y.D., Yu A.B., A Simulation Study of the Effects of Dynamic Variables on the Packing of Spheres, Powder Technology., 116: 23- (2001).
[32] Cundall B., Strack O.D.L., A Discrete Element Model for Granular Assemblies, Geotechnique., 29: 47- (1979).
[33] Theuerkauf J., Witt P., Schwesig D., Analysis of Particle Porosity Distribution in Fixed Beds Using the Discrete Element Method, Powder Technology., 165: 92- (2006).
[35] Freund H., Zeiser T., Huber F., Klemm E., Brenner G., Durst F., Emig G., Numerical Simulations of Single Phase Reacting Flows in Randomly Packed Fixed-Bed Reactors and Experimental Validation, Chem. Eng. Sci., 58: 903- (2003).
[36] Perry R.H., D.W. Green Eds., "Perry’s chemical engineering handbook", 7th Ed, Mc Graw Hill, New York (1997).
[37] Levenspiel O., "Chemical Reaction Engineering", 2nd Ed, Wiley & Sons, New York (1972).