3D Numerical Study of Multiphase Counter-Current Flow within a Packed Bed for Post Combustion Carbon Dioxide Capture
3D Numerical Study of Multiphase Counter-Current Flow within a Packed Bed for Post Combustion Carbon Dioxide Capture
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DOI：
10.3390/en11061441
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发表时间：
2018-06
期刊：
影响因子：
3.2
通讯作者：
Li Yang;Fang Liu;Zhengchang Song;Kunlei Liu;Kozo Saito
中科院分区：
文献类型：
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作者：
Li Yang;Fang Liu;Zhengchang Song;Kunlei Liu;Kozo Saito
逆流流动填充床内的流体动力学对于提供对可能影响用于燃烧后CO2捕获的工艺中的反应器和反应效率的设计和操作参数的了解是至关重要的。然而，在这些过程中使用的随机填料中的多相逆流流动是复杂的可视化。因此，这项工作旨在开发一个计算流体动力学（CFD）模型，以更精确地研究填充床内流动的复杂细节。模拟结果清楚地显示了在不同的气体和液体流量下液体分布、润湿面积和膜厚度的发展和变化。随着We数的增加，液体分布更加均匀，并且随着We数的增加，流动模式从液滴流变为膜流和滴流。相反，增加气体流量对润湿面积和持液率没有显著影响。还确定了液体入口的数量影响流动行为，并且液体表面张力对压降或持液率的影响微不足道;然而，较低的表面张力提供较大的润湿面积和较薄的膜。进行实验研究，使实验测量的压降和模拟确定的压降之间的比较，实验数据和模拟数据之间显示出密切的对应关系和相似的趋势，因此，得出的结论是，模拟模型是有效的，可以合理地预测逆流流动填充床内的流动动力学。
The hydrodynamics within counter-current flow packed beds is of vital importance to provide insight into the design and operational parameters that may impact reactor and reaction efficiencies in processes used for post combustion CO2 capture. However, the multiphase counter-current flows in random packing used in these processes are complicated to visualize. Hence, this work aimed at developing a computational fluid dynamics (CFD) model to study more precisely the complex details of flow inside a packed bed. The simulation results clearly demonstrated the development of, and changes in, liquid distributions, wetted areas, and film thickness under various gas and liquid flow rates. An increase in values of the We number led to a more uniform liquid distribution, and the flow patterns changed from droplet flow to film flow and trickle flow as the We number was increased. In contrast, an increase in gas flow rate had no significant effect on the wetted areas and liquid holdup. It was also determined that the number of liquid inlets affected flow behavior, and the liquid surface tension had an insignificant influence on pressure drop or liquid holdup; however, lower surface tension provided a larger wetted area and a thinner film. An experimental study, performed to enable comparisons between experimentally measured pressure drops and simulation-determined pressure drops, showed close correspondence and similar trends between the experimental data and the simulation data; hence, it was concluded that the simulation model was validated and could reasonably predict flow dynamics within a counter-current flow packed bed.