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Computational Fluid Dynamics-Discrete Element Method (CFD-DEM) Study of Mass-Transfer Mechanisms in Riser Flow
Álvaro E Carlos Varas1, E A J F Peters1, J A M Kuipers1
1Department of Chemical Engineering and Chemistry, Multiphase Reactors Group, Eindhoven University of Technology, 5600 MB Eindhoven, The Netherlands.
Industrial & Engineering Chemistry Research
|May 30, 2017
Summary
Particle clusters significantly impact mass transfer in gas-solid riser reactors. Lower air-to-solids ratios increase clustering, reducing gas-solid contact efficiency and affecting reactor performance.
Area of Science:
- Chemical Engineering
- Fluid Dynamics
- Particle Technology
Background:
- Cocurrent gas-particle flows in risers are crucial for chemical reactions.
- Understanding mass transfer and reaction kinetics in these systems is complex.
- Particle clustering significantly influences flow dynamics and efficiency.
Purpose of the Study:
- To investigate the interplay between mass transfer and heterogeneous catalysis in riser flows.
- To analyze the impact of particle clustering on gas-solid contact efficiency.
- To quantify the influence of various flow parameters on riser reactor performance.
Main Methods:
- Computational Fluid Dynamics-Discrete Element Method (CFD-DEM) simulations.
- Evaluation of slip velocity, axial gas dispersion, gas bypassing, and particle mixing.
- Analysis under various riser flow conditions and parameter variations.
Main Results:
- Particle cluster formation is a key factor affecting mass transfer.
- Low air-to-solids flux ratios promote heterogeneous systems and pronounced clustering.
- Falling clusters reduce gas-solid contact efficiency due to gas bypassing.
Conclusions:
- Particle clustering critically impacts the performance of riser reactors.
- Optimizing air-to-solids flux ratios can mitigate negative clustering effects.
- Quantifying cluster effects provides insights for improved reactor design and operation.
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