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化工学报  2015 

颗粒内部毛细凝聚对气体有效扩散系数的影响

DOI: 10.11949/j.issn.0438-1157.20141309, PP. 1363-1369

Keywords: 毛细凝聚,有效扩散系数,多孔介质,内扩散,滞后环

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Abstract:

采用改进型Wicke-Kallenbath稳态扩散池,在373~413K及0.4~1.0MPa条件下测定了氢气在某工业催化剂CuO/ZnO/γ-Al2O3内部的有效扩散系数。实验采用逐步增加环己烷流量至某最大值而后逐步降低回到初始点的方法,测定了催化剂孔内发生毛细凝聚时氢气有效扩散系数随环己烷蒸气相对压力的变化。实验结果表明:在373K下环己烷蒸气相对压力为0.42时开始发生毛细凝聚,而在413K下则延迟到0.6才开始出现这一现象。此外,滞后环宽度随着温度的升高而变窄,并且氢气的有效扩散系数随环己烷蒸气相对压力变化出现多重滞后环。建立了催化剂部分润湿时氢气的有效扩散系数与内部润湿分率的关联式,与实验测量值符合较好。

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