CFD Simulation of Porosity and Particle Diameter Influence on Wall-to-Bed Heat Transfer in Trickle Bed Reactors

Document Type : Research Paper

Authors

Faculty of Chemical, Petroleum and Gas Engineering, campus No.1, Semnan university, Semnan, Iran

Abstract

Wall-to-bed (or wall-to-fluid) heat transfer issues in trickle bed reactors (TBR) has an important impact on operation and efficiency in this category of reactors. In this study, the hydrodynamic and thermal behavior of trickle bed reactors was simulated by means of computational fluid dynamics (CFD) technique. The multiphase behavior of trickle bed reactor was studied by the implementation of the Eulerian-Eulerian multiphase approach. Also, bed porosity effect was modeled by porosity function method. In order to study the effect of operating parameters on wall-to-bed heat transfer, the influence of catalyst particle diameter and catalytic bed porosity was investigated on wall-to-bed Nu number. The results showed that the enhancement of catalytic bed porosity from 0.36 to 0.5 decreases the Nu number about 15% due to a reduction of liquid velocity adjacent to the reactor wall. Also, the increase of particle diameter from 4 to 6 millimeter decreases wall-to-bed Nu number about 15% owing to a reduction in liquid phase volume fraction.

Keywords


[1] Dixon AG, Nijemeisland M, Stitt EH. Packed tubular reactor modeling and catalyst design using computational fluid dynamics. Advances in Chemical Engineering. 2006 Jan 1;31:307-89.
[2] Miroliaei AR, Shahraki F, Atashi H. Computational fluid dynamics simulations of pressure drop and heat transfer in fixed bed reactor with spherical particles. Korean Journal of Chemical Engineering. 2011 Jun 1;28(6):1474-9.
[3] Nijemeisland M, Dixon AG. Comparison of CFD simulations to experiment for convective heat transfer in a gas–solid fixed bed. Chemical Engineering Journal. 2001 Mar 15;82(1-3):231-46.
[4] Peng W, Xu M, Huai X, Liu Z. CFD study on local fluid-to-wall heat transfer in packed beds and field synergy analysis. Journal of Thermal Science. 2016 Apr 1;25(2):161-70.
[5] Muroyama K, Hashimoto K, Tomita T. Heat transfer from wall in gas-liquid cocurrent packed beds. Heat Transfer - Japanese Research. 1978;7(1):87-93.
[6] Specchia V, Baldi G. Heat transfer in trickle-bed reactors. Chemical Engineering Communications. 1979 Nov 1;3(6):483-99.
[7] Mariani NJ, Mazza GD, Martínez OM, Cukierman AL, Barreto GF. On the influence of liquid distribution on heat transfer parameters in trickle bed systems. The Canadian Journal of Chemical Engineering. 2003 Jun;81(3‐4):814-20.
[8] Heidari A, Hashemabadi SH. CFD simulation of isothermal diesel oil hydrodesulfurization and hydrodearomatization in trickle bed reactor. Journal of the Taiwan Institute of Chemical Engineers. 2014 Jul 1;45(4):1389-402.
[9] Heidari A, Hashemabadi SH. CFD study of diesel oil hydrotreating process in the non-isothermal trickle bed reactor. Chemical Engineering Research and Design. 2015 Feb 1;94:549-64.
[10] Gunjal PR, Kashid MN, Ranade VV, Chaudhari RV. Hydrodynamics of trickle-bed reactors: experiments and CFD modeling. Industrial & Engineering Chemistry Research. 2005 Aug 3;44(16):6278-94.
[11] Gunjal PR, Ranade VV. Modeling of laboratory and commercial scale hydro-processing reactors using CFD. Chemical Engineering Science. 2007 Sep 1;62(18-20):5512-26.
[12] Attou A, Ferschneider G. A two-fluid model for flow regime transition in gas–liquid trickle-bed reactors. Chemical Engineering Science. 1999 Nov 1;54(21):5031-7.
[13] Salimi M, Hashemabadi SH, Noroozi S, Heidari A, Bazmi M. Numerical and Experimental Study of Catalyst Loading and Body Effects on a Gas‐Liquid Trickle‐Flow Bed. Chemical Engineering & Technology. 2013 Jan;36(1):43-52.