Comparative study on the numerical simulation of hydrogen separation through palladium and palladium?copper membranes
Comparative study on the numerical simulation of hydrogen separation through palladium and palladium?copper membranes
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钯膜与钯铜膜分离氢气数值模拟对比研究
DOI：
10.1016/j.ijhydene.2022.05.094
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发表时间：
2022
影响因子：
7.2
通讯作者：
Hayakawa Yukio
中科院分区：
文献类型：
--
作者：
El-Shafie Mostafa;Kambara Shinji;Hayakawa Yukio
通过建立二维计算流体力学模型，对氢气在钯（Pd）膜和钯铜（Cu）膜中的扩散行为进行了数值模拟.在垂直圆柱形反应器中，求解了不同操作条件下层流条件下的动量和质量传递现象。模拟并比较了两种钯基膜的进料间隙距离、氢气浓度和反应器加热温度对氢气渗透过程的影响。利用所设计的模型分析了浓度、速度、对流和扩散传质通量的分布。H2浓度与进料间隙距离/横截面积成正比。进料间隙距离越小，H2分子被膜表面吸附的可能性越大，电离能越大，导致H2通过Pd基膜进一步解离.结果发现，所有进料浓度的扩散通量在渗透过程开始后50秒显著降低。在相同的操作条件下，Pd-Cu 40%膜的扩散通量比纯Pd膜的扩散通量大。Pd-Cu 40%膜的对流通量、扩散传质通量和浓度的分布在高达350 °C时显著增加，然后在较高温度下下降到较低值。模拟结果与实验结果进行了验证，分析表明，在相同的操作条件下，模拟结果与实验结果吻合较好。可以得出结论，钯基膜的模拟建模是能够预测在高H2扩散速率的最佳操作条件。
The hydrogen (H2) diffusion through palladium (Pd) and Pd–copper (Cu) membranes was numerically investigated by developing a two-dimensional computational fluid dynamics model for predicting the performance of H2separation. The momentum and mass transport phenomena in the laminar flow conditions were solved at different operating conditions in a vertical cylindrical-type reactor. The effect of feed-gap distance, H2concentration, and reactor heating temperature on the H2permeation processes were simulated and compared for both Pd-based membranes. The concentration, velocity, and convective and diffusion mass transfer flux distributions were analyzed using the designed model. The H2concentration was proportional to the feed-gap distance/cross-sectional area. The smaller the feed-gap distance, the greater the probability of a H2molecule being adsorbed by the membrane surface and the ionization energy increasing, leading to further H2dissociation through the Pd-based membranes. It was found that the diffusion flux of all feed concentrations was substantially decreased 50 s after the start of the permeation process. Moreover, the diffusion flux of the Pd–Cu40% membrane was relatively larger than that of the pure Pd membrane under the same operating conditions. The distributions of the convective flux, diffusion mass transfer flux, and concentration of the Pd–Cu40% membrane were substantially increased up to 350 °C, then fell to a lower value at higher temperatures. The simulation results were validated with the experimental results, with analysis indicating a good agreement with the experimental results under the same operating conditions. It can be concluded that the simulation modeling for Pd-based membranes was able to predict the optimum operating conditions at high H2diffusion rates.