Simulation of the Flow in a Packed-Bed with and without a Static Mixer by Using CFD Technique

Authors: Phavanee Narataruksa, Karn Pana-Suppamassadu, Sabaithip TungkamaniRungrote Kokoo, Prayut Jiamrittiwong

Abstract:

The major focus of this work was to characterize hydrodynamics in a packed-bed with and without static mixer by using Computational Fluid Dynamic (CFD). The commercial software: COMSOL MULTIPHYSICSTM Version 3.3 was used to simulate flow fields of mixed-gas reactants i.e. CO and H2. The packed-bed was a single tube with the inside diameter of 0.8 cm and the length of 1.2 cm. The static mixer was inserted inside the tube. The number of twisting elements was 1 with 0.8 cm in diameter and 1.2 cm in length. The packed-bed with and without static mixer were both packed with approximately 700 spherical structures representing catalyst pellets. Incompressible Navier-Stokes equations were used to model the gas flow inside the beds at steady state condition, in which the inlet Reynolds Number (Re) was 2.31. The results revealed that, with the insertion of static mixer, the gas was forced to flow radially inward and outward between the central portion of the tube and the tube wall. This could help improving the overall performance of the packed-bed, which could be utilized for heterogeneous catalytic reaction such as reforming and Fischer- Tropsch reactions.

Keywords: Packed Bed, Static Mixer, Computational Fluid Dynamic (CFD).

Digital Object Identifier (DOI): doi.org/10.5281/zenodo.1078831

References:

[1] Pedernera, M.N. et al., Use of a heterogeneous two-dimensional model to improve the primary steam reformer performance Chemical Engineering Journal. 94 (2003): 29-40.
[2] Stitt, E.H. NATO Science Series II, Kluwer Academic Publishers, Dordrecht, 191 (2005): 185-216. E.H. Stitt, Reactor technology for syngas and hydrogen. In: E. Derouane, V. Parmon, F. Lemos and F. Ramoa-Ribiero, Editors, Sustainable Strategies for the Upgrading of Natural Gas: Fundamentals, Challenges and Opportunities, NATO Science Series II vol. 191, Kluwer Academic Publishers, Dordrecht (2005), pp. 185-216
[3] Sie, S.T. & Krishna, R. Process development and scale up: II. Catalyst design strategy. Reviews in Chemical Engineering. 14 (1998): 159-202.
[4] Bruno, S.P. et al., Effect of the geometric characteristics of commercial catalysts for steam reforming. Chemical Engineering Journal. 39 (1988): 147-156.
[5] Andersson, S. & SchLoLon, N. Industrial and Engineering Chemistry Research. 32 (1993): 1081-1086.
[6] Khinast, G. J. et al., Mass -transfer enhancement by static mixers in a wall-coated catalytic reactor Chemical Engineering Science. 58 (2003): 1063-1070.
[7] Mariani, N.J. et al., A one-dimensional equivalent model to evaluate overall reaction rates in catalytic pellets, Transactions of the Institution of Chemical Engineers. 81 (2003): 1033-1042.
[8] Keegan, S.D. et al., Behavior of catalytic pellets at high reaction rates. The effect of edges, Industrial and Engineering Chemistry Research. 45 (2006): 85-97.