Evaluation of CO2 removal from a CO2+CH4 gas mixture using gas hydrate formation in liquid water and THF solutions
Evaluation of CO2 removal from a CO2+CH4 gas mixture using gas hydrate formation in liquid water and THF solutions
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DOI：
10.1016/j.apenergy.2015.08.058
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发表时间：
2015-11
期刊：
影响因子：
11.2
通讯作者：
D. Zhong;Zheng Li;Yiyu Lu;Jia-le Wang;Jin Yan
中科院分区：
文献类型：
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作者：
D. Zhong;Zheng Li;Yiyu Lu;Jia-le Wang;Jin Yan
在这项工作中，评估了在液态水、THF 和 THF/SDS 溶液中形成水合物以从模拟回收的页岩气（40 mol% CO2 和 60 mol% CH4）中去除 CO2 的性能。实验在固定温度 277.15 K 和压力范围 (2.8–6.7) MPa 下进行。在液态水和 THF 溶液中研究了驱动力（超压）对水合物生长和 CO2 选择性的影响。研究发现，较高的驱动力会导致最终气体吸收量减少以及 CO2 回收率和分离因子显着降低。结果表明，在高驱动力下，水合物生长的传质受到极大阻碍，并且随着驱动力的增加，CH4和CO2分子之间对水合物空穴占据的竞争变得更强。尽管通过在液态水中添加THF和SDS改善了CO2/CH4气体混合物形成水合物的动力学，但与液态水中相比，从CO2/CH4气体混合物中去除CO2的选择性受到损害。在液态水中以低驱动力 (2.5 MPa) 获得最高的 CO2 回收率 (52%) 和分离因子 (8.8)，远高于在 THF 和 THF/SDS 溶液中获得的结果。因此，在不降低CO2选择性的情况下增强水合物形成动力学是改进基于水合物的气体分离工艺从CO2/CH4气体混合物中去除CO2的关键因素。
In this work, the performance of hydrate formation for CO2removal from a simulated recovered shale gas (40 mol% CO2and 60 mol% CH4) was evaluated in liquid water, and THF and THF/SDS solutions. Experiments were carried out at a fixed temperature of 277.15 K and in the pressure range of (2.8–6.7) MPa. The impact of driving force (overpressure) on hydrate growth and CO2selectivity was studied both in liquid water and in THF solutions. It was found that higher driving force resulted in a reduction of the final gas uptake as well as a significant decrease of the CO2recovery and separation factor. The results indicated that mass transfer for hydrate growth was greatly hindered at high driving force, and the competition between CH4and CO2molecules for the occupancy of hydrate cavities became stronger with the increase of driving force. Although the kinetics of hydrate formation with the CO2/CH4gas mixture was improved by adding THF and SDS into liquid water, the selectivity for CO2removal from the CO2/CH4gas mixture was compromised as compared to that in liquid water. The highest CO2recovery (52%) and separation factor (8.8) were obtained at a low driving force (2.5 MPa) in liquid water, which were much higher than those obtained in THF and THF/SDS solutions. As a result, enhancing the kinetics of hydrate formation without reducing CO2selectivity is the key factor to improve the hydrate based gas separation process for CO2removal from the CO2/CH4gas mixture.