Hydrodynamic and Heat Transfer Study of a Fluidized Bed by Discrete Particle Simulations

Lijing Mu,J A M Kuipers,Niels G Deen,Kay A Buist

doi:10.3390/pr8040463

Abstract

A numerical simulation study was carried out to study the combined thermal behavior and hydrodynamics of a pseudo-2D fluidized bed using a computational fluid dynamics–discrete element method (CFD-DEM). To mimic the effect of heterogeneous exothermic reactions, a constant heat source was implemented in the particle energy equation. The effects of superficial gas velocity, bed height and heat source distribution were analyzed with the aid of averaged volume fraction and temperature distributions and velocity profiles. It was found that both the gas superficial velocity and the bed aspect ratio have a profound influence on fluidization behavior and temperature distributions.

Highlights

Fluidized beds find widespread application in various industrial processes because of their favorable heat transfer characteristics
We present computational fluid dynamics–discrete element method (CFD-discrete element method (DEM)) simulations of a pseudo-2D fluidized bed with spherical particles, through which we studied the influence of particle size and superficial gas velocity on fluidized bed thermal behavior
Different gas superficial velocities and varying aspect ratios: 0.5, and different gas superficial velocities and varying aspect ratios: 0.5, and heat source was incorporated in the particle phase thermal energy equation to mimic the heat liberation due to chemical conversion

Summary

Introduction

Fluidized beds find widespread application in various industrial processes because of their favorable heat transfer characteristics. Many of the important applications of fluidized beds involve reactions with large heat effects. This may give rise to high rates of heat removal or production. Examples can be found in fluidized bed coal combustion, fluid catalytic cracking and polymerization processes for the production of polyethylene. For a proper understanding of the role of heat production and transport, detailed knowledge is required. This includes considering studies of the fluidized bed hydrodynamics and heat transfer

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