A combined theoretical and experimental analysis on transient breakthroughs of C2H6/C2H4 in fixed beds packed with ZIF-7
A combined theoretical and experimental analysis on transient breakthroughs of C2H6/C2H4 in fixed beds packed with ZIF-7
复制标题
ZIF-7固定床中C2H6/C2H4瞬时突破的理论与实验结合分析
DOI：
10.1016/j.micromeso.2015.01.019
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发表时间：
2015-05-15
影响因子：
5.2
通讯作者：
Krishna, Rajamani
中科院分区：
文献类型：
--
作者：
Chen, De-Li;Wang, Ningwei;Krishna, Rajamani
通过沸石咪唑酯骨架ZIF-7可以实现C2 H6/C2 H4混合物的选择性分离，ZIF-7是一种众所周知的柔性微孔材料，由于其响应于外部刺激如压力和温度的开门效应。在不同的压力和温度条件下进行了C2 H6/C2 H4混合物的瞬态穿透实验，以确认ZIF-7在吸附循环期间选择性吸附饱和烷烃并拒绝气相中的不饱和烯烃的潜在应用。瞬态突破模拟，包括晶内扩散的影响，进行了比较与实验突破。可忽略的扩散限制的假设是能够捕捉到的实验突破的本质特征。在实验和模拟研究的基础上，计算了ZIF-7分子筛对C2 H6和C2 H4的吸附量，并与理想吸附溶液理论计算结果进行了比较。推导出的等量吸附热的两种吸附物进行了比较，并用于解释在ZIF-7中的C2 H4的C2 H6的吸附选择性。实验和模拟之间的良好的一致性验证，在当前的研究中采用的模拟方法是一个有价值的和有效的工具，用于建模的C2 H6/C2 H4混合物在ZIF-7的分离性能。(C)2015 Elsevier Inc. All rights reserved.
The selective separation of C2H6/C2H4 mixtures can be achieved by the zeolitic imidazolate framework ZIF-7, which is a well-known flexible microporous material due to its gate-opening effect in response to external stimuli such as pressure and temperature. Transient breakthrough experiments with C2H6/C2H4 mixtures were carried out at varying pressure and temperature conditions to confirm the potential application of ZIF-7 to selectively adsorb the saturated alkane and reject the unsaturated alkene in the gas phase during the adsorption cycle. Transient breakthrough simulations, including the influence of intra-crystalline diffusion, were compared with the experimental breakthroughs. The assumption of negligible diffusional limitations is able to capture the essential characteristics of the experimental breakthroughs. With the breakthroughs from both experiments and simulations, the adsorbed amounts of C2H6 and C2H4 in ZIF-7 were calculated to estimate the separation selectivity, which is in reasonable agreement with ideal adsorbed solution theory calculations. The derived isosteric heats of adsorption for both adsorbates are compared and used to explain the adsorption selectivity for C2H6 over C2H4 in ZIF-7. The good agreement between experiments and simulations verifies that the simulation methodology employed in the current study is a valuable and efficient tool for modeling the separation performance of C2H6/C2H4 mixtures in ZIF-7. (C) 2015 Elsevier Inc. All rights reserved.