Zhang Jie, Liu Hong, Zhou Fubao, Li Xingcheng, Wei Kangwei, Song Jiaojiao
Jiangsu Key Laboratory of Fire Safety in Urban Underground Space, China University of Mining and Technology (CUMT), Xuzhou 221116, PR China.
Faculty of Safety Engineering, China University of Mining and Technology (CUMT), Xuzhou 221116, PR China.
ACS Omega. 2021 Mar 5;6(10):6914-6923. doi: 10.1021/acsomega.0c06148. eCollection 2021 Mar 16.
A type of carbon molecular sieve (CMS-3KT) was used as the adsorbent for the CH enrichment of a methane/oxygen/nitrogen (CH/O/N) mixture using micro-positive pressure vacuum pressure swing adsorption (∼120 kPa). The adsorption isotherms of individual CH, O, and N on CMS-3KT were studied and fitted. The results indicated the important influence of the adsorbent surface heterogeneity on the adsorption equilibrium process. In addition, the interaction of adsorbent-adsorbate in this process was studied from the measured adsorption heat. The adsorption uptake curves were fitted linearly with a classical micropore model for evaluating the kinetics-based separation possibility of CH/O/N, and the corresponding diffusion time constants of CH, O, and N were calculated. Based on the results of adsorption equilibrium and kinetics, breakthrough experiments were employed to explore the upper limit value of methane concentration in feed gas such that methane can be enriched feasibly but difficultly. The breakthrough experiments were performed on the CH/O/N mixture with CH concentration ranging from 1 to 30%. Regarding industrial application, the O removal and CH enrichment performance of ultra-low-concentration methane (CH < 5%) were evaluated according to the results of the breakthrough experiment. The results indicated that the proposed method was promising for enriching O-containing ultra-low-concentration CBM.
一种碳分子筛（CMS-3KT）被用作吸附剂，采用微正压变压吸附（约120 kPa）对甲烷/氧气/氮气（CH₄/O₂/N₂）混合物中的CH₄进行富集。研究并拟合了CH₄、O₂和N₂在CMS-3KT上的吸附等温线。结果表明吸附剂表面非均质性对吸附平衡过程有重要影响。此外，根据测得的吸附热研究了该过程中吸附剂 - 吸附质的相互作用。用经典微孔模型对吸附量曲线进行线性拟合，以评估CH₄/O₂/N₂基于动力学的分离可能性，并计算了CH₄、O₂和N₂相应的扩散时间常数。基于吸附平衡和动力学结果，进行了穿透实验，以探索原料气中甲烷浓度的上限值，使得甲烷能够可行但困难地被富集。对CH₄浓度范围为1%至30%的CH₄/O₂/N₂混合物进行了穿透实验。对于工业应用，根据穿透实验结果评估了超低浓度甲烷（CH₄ < 5%）的O₂脱除和CH₄富集性能。结果表明，所提出的方法对于富集含O₂的超低浓度煤层气具有前景。
