CFD-simulation of gas-solid flow in bubbling fluidized bed reactor

Oumaima El Ajouri,Mohamed Lhassane Lahlaouti,Bousselham Kharbouch,B Benhala,A Raihani,K Mansouri,M Qbadou

doi:10.1051/e3sconf/202233600059

Oumaima El Ajouri, Mohamed Lhassane Lahlaouti + Show 5 more

Open Access

https://doi.org/10.1051/e3sconf/202233600059

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Abstract

The hydrodynamic behaviour of gas-solid flow has been studied in a two-dimensional bubbling fluidized bed reactor filled with particles of 275 µm in size, using computational fluid dynamics (CFD). The two-fluid model (TFM) approach based on the concept of Eulerian–Eulerian in combination with Kinetic Theory of Granular Flow (KTGF) is used to represent the fluid mechanics involved in the flow. The computational implementation was realized by the commercial software ANSYS FLUENT. Interphase momentum exchange between gas and solid phases were calculated using the modified Syamlal O’Brien drag force function. The simulation predictions have been comprehensively validated with experimental data measurements of bed expansion rate, pressure drops and average gas volume fraction profiles. The pressure drops predicted by the simulations were in comparatively strong agreement with the experimental data at higher superficial gas velocities. The bed expansion ratio of the simulation results is closer to that of the experimental data. This work provides a scalable means to assist in the design and operation of fluidised bed reactors and fluidisation processes.

Highlights

In recent years, due to its renewable, durable and environmentally friendly nature of biomass energy production has gained a great deal of interest within the research scientific community and the industrial engineering sector
The fluidized bed reactors can facilitate the study of thermochemical processes associated with biomass gasification, they help to investigate and to evaluate the effects of operational parameters on gasifier performance and product quality [5], [6]
Simulation results indicated that small bubbles were produced at the bottom of the bed. this study showed that the two-fluid model (TFM) model and the use of Syamlal O’Brien drag force can predict hydrodynamic and heat-transfer behaviour of gas-solid fluidized-bed reactors reasonably well

Summary

Introduction

Due to its renewable, durable and environmentally friendly nature of biomass energy production has gained a great deal of interest within the research scientific community and the industrial engineering sector. Biomass fuel can reduce dependence on energy production via fossil fuels, reducing the associated adverse environmental impacts [1,2]. Biomass gasification is always faced with a variety of technical challenges, pushing back potential commercialization. Among these challenges are the propagation of the complex chemical reactions within the fluidization zone and the limitations imposed by the process control and the prediction difficulty of momentum models due to the turbulent flow behaviour of the gas and the flowing particles [3]. The fluidized bed reactors can facilitate the study of thermochemical processes associated with biomass gasification, they help to investigate and to evaluate the effects of operational parameters on gasifier performance and product quality [5], [6]

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