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International Journal of Chemical Engineering
Volume 2012 (2012), Article ID 786982, 13 pages
http://dx.doi.org/10.1155/2012/786982
Research Article

Numerical Studies of the Gas-Solid Hydrodynamics at High Temperature in the Riser of a Bench-Scale Circulating Fluidized Bed

1School of Chemical Engineering, University of Campinas, 500 Albert Einstein Avenue, Campinas 13083-970, SP, Brazil
2Department of Mechanical Engineering, Federal University of Technology of Parana, Monteiro Lobato Avenue, 84016-210 Ponta Grossa, PR, Brazil
3Faculty of Mechanical Engineering, University of Campinas, 200 Mendeleyev Avenue, Campinas, 13083-970, SP, Brazil

Received 8 May 2012; Revised 3 July 2012; Accepted 10 July 2012

Academic Editor: Adrian Schumpe

Copyright © 2012 Maximilian J. Hodapp et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

The hydrodynamics of circulating fluidized beds (CFBs) is a complex phenomenon that can drastically vary depending on operational setup and geometrical configuration. A research of the literature shows that studies for the prediction of key variables in CFB systems operating at high temperature still need to be implemented aiming at applications in energy conversion, such as combustion, gasification, or fast pyrolysis of solid fuels. In this work the computational fluid dynamics (CFD) technique was used for modeling and simulation of the hydrodynamics of a preheating gas-solid flow in a cylindrical bed section. For the CFD simulations, the two-fluid approach was used to represent the gas-solid flow with the k-epsilon turbulence model being applied for the gas phase and the kinetic theory of granular flow (KTGF) for the properties of the dispersed phase. The information obtained from a semiempirical model was used to implement the initial condition of the simulation. The CFD results were in accordance with experimental data obtained from a bench-scale CFB system and from predictions of the semiempirical model. The initial condition applied in this work was shown to be a viable alternative to a more common constant solid mass flux boundary condition.