Separation of Methane/Ethylene Gas Mixtures Using Wet ZIF‑8

• Published in: Industrial & engineering chemistry research 2015-08, Vol.54 (32), p.7890-7898
• Main Authors: Zhang, Xiao-Xin, Xiao, Peng, Zhan, Chang-Hua, Liu, Bei, Zhong, Rui-Qin, Yang, Lan-Ying, Sun, Chang-Yu, Liu, Huang, Pan, Yong, Chen, Guang-Jin, Li, Nan
• Format: Article
• Language: English
• Subjects: Adsorption; Ethylene; Formations; Gas mixtures; Hydrates; Methane; Moisture content; Separation
• ISSN: 0888-5885; 1520-5045
• DOI: 10.1021/acs.iecr.5b00941

The separation of methane/ethylene gas mixtures by the adsorption–hydration method was investigated by using a wet zeolitic imidazolate framework (ZIF) microporous material, ZIF-8. The influences of the initial gas–solid ratio (the volume ratio of gas mixture to ZIF-8) and water content of wet ZIF-8 on the separation performance were studied systematically at 274.15 K. The experimental results show that gas–solid ratio of ca. 310 and water content of ca. 38.50 wt % are the suitable conditions for the separation of methane/ethylene mixture with wet ZIF-8 on the premise of hydrate formation. When water content of wet ZIF-8 is 38.50 wt % and the gas–solid ratio is 297, the mole fraction of ethylene in gas phase decreases from 30.91% to 14.44%, the selectivity coefficient reaches 5.57, and the adsorption quantity of ethylene reaches 3.37 mmol/g after one stage of the adsorption–hydration process. Compared with a single adsorption method or hydration method, methane/ethylene gas mixtures can be further separated with the synergistic effect of gas adsorption and hydrate formation. The morphology and crystal structure of ZIF-8 remains after a series of processes of saturation with water, adsorption–hydration, hydrate decomposition, and drying.