Kinetics of spontaneous liquid-gas imbibition in carbon molecular sieves used for O-2/N-2 separation
Kinetics of spontaneous liquid-gas imbibition in carbon molecular sieves used for O-2/N-2 separation
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用于 O-2/N-2 分离的碳分子筛中自发液气吸入动力学
DOI：
10.1016/j.micromeso.2016.12.040
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发表时间：
2017
影响因子：
5.2
通讯作者：
Cong Yuanyuan
中科院分区：
文献类型：
--
作者：
Jia Xinyu;Xu Shaoping;Cong Yuanyuan
研究了用于空气分离的碳分子筛（CMS）微孔中自发液气吸入的动力学。基于动力学，可以估计CMS的微孔结构，并建立了CMS在变压吸附（PSA）中O2/N2分离性能的新评估方法。选择水作为吸入液体探针，选择N2和O2作为气体探针。采用伪二级（PSO）动力学模型和线性驱动力（LDF）模型证实水-O2/N2自发吸吸的限速步骤主要归因于水的表面吸附和气体通过CMS微孔入口或内部的扩散。水分子先于较宽的微孔口侵入较窄的微孔口。建立 O2/N2 选择性系数 K 来评估 CMS 的空气分离性能。当K值等于0时，CMS内微孔口的尺寸分布最适合空气分离，可以获得最高的N2产量。但随着K逐渐偏离零，CMS的空气分离性能下降。
The kinetics of spontaneous liquid-gas imbibition in micropores of carbon molecular sieves (CMSs) used for air separation has been investigated. Based on the kinetics, the microporous textures of CMSs could be estimated, and a new assessment method for O2/N2separation performance of CMSs in pressure swing adsorption (PSA) was established. Water was chosen as the imbibition liquid probe, and N2and O2were chosen as the gas probes. The pseudo-second-order (PSO) kinetic model and the linear driving force (LDF) model were employed to confirm that the rate-limiting steps of the spontaneous water-O2/N2imbibition were mainly attributable to the surface adsorption of water and the diffusion of gas through the micropore entrence or interior in CMSs. Water molecules invade into the narrower micropore mouths prior to the wider micropore mouths. An O2/N2selectivity coefficient K was established to assess the air separation performance of CMSs. When the K value is equal to zero, the size distribution of micropore mouths in CMSs is the fittest for the air separation and the highest N2production can be obtained. But with K gradually deviating zero, the air separation performance of CMSs decreases.