A new approach to the upgrading of the traditional propylene carbonate washing process with significantly higher CO2 absorption capacity and selectivity
A new approach to the upgrading of the traditional propylene carbonate washing process with significantly higher CO2 absorption capacity and selectivity
复制标题
传统碳酸丙烯酯洗涤工艺升级的新方法，显着提高二氧化碳吸收能力和选择性
DOI：
10.1016/j.apenergy.2019.01.236
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发表时间：
2019-04-15
期刊：
影响因子：
11.2
通讯作者：
Qin, Huibo
中科院分区：
文献类型：
--
作者：
Chen, Wan;Chen, Mengzijing;Qin, Huibo
虽然一系列先进的技术和材料，如离子液体和金属有机框架，正在开发用于碳捕获，传统的技术，如碳酸丙烯酯（PC）洗涤，仍然广泛应用于工业，因为它们的材料成本低，易于操作。考虑到PC的低CO2溶解度和选择性，我们尝试在乙二醇（EG）作为助溶剂的情况下，在PC中加入2-甲基咪唑（mIm）来改善PC的洗涤工艺。制备了一系列EG-mIm-PC复合溶剂，并测定了其在不同温度下的粘度。在293.15、303.15和313.15 K、0.1-0.8 MPa条件下，测定了这些复合吸收体以及纯PC对CO2的吸收等温线。用克劳修斯-克拉珀龙方程计算了这些溶剂混合物中CO2的吸收热。为了评价mIm对CO2对其他气体选择性的影响，还测量了CH4、N-2和H-2在纯PC和CO2溶解度最高的24%-mIm复合溶剂中的吸收等温线。结果表明：当mIm含量低于20% wt%时，随着mIm质量分数的增加，复合吸附剂的粘度、溶解度和CO2吸收热均有中等或缓慢的增加；当mIm含量超过20% wt%时，复合吸附剂的粘度迅速增加；当mIm含量达到24 wt%时，CO2溶解度可以提高一倍以上，而粘度和吸收热仍然保持在较低的水平，即低于14 mPa。s和26kj /mol。更重要的是，在mIm的存在下，CH4、N-2和H-2的溶解度急剧下降；使用24 wt%-mIm络合吸附剂代替纯PC， CO2对CH4的选择性提高了0.7 ~ 2.8倍，对N-2的选择性提高了3.9 ~ 6.3倍，对H-2的选择性提高了3.5 ~ 7.7倍，且在较低压力范围内提高更为显著。这项工作为PC洗涤技术的升级提供了一条非常有前途的途径。
Although a series of advanced technologies and materials, like ionic liquids and metal organic frameworks, is being developed for carbon capture, traditional techniques, like propylene carbonate (PC) washing, are still widely applied in industry because of their low material costs and ease of operation. Considering the low CO2 solubility and selectivity in PC, we have tried to improve the PC washing process by adding 2-methylimidazole (mIm) to PC in the presence of ethylene glycol (EG) as cosolvent. A series of EG-mIm-PC complex solvents was prepared and their viscosities measured at different temperatures. The absorption isotherms of CO2 in these complex absorbents, as well as in pure PC, were measured at 293.15, 303.15, and 313.15 K at 0.1-0.8 MPa. The heats of CO2 absorption in these solvent mixtures were calculated using the Clausius-Clapeyron equation. For evaluating the effect of mIm on the selectivity of CO2 over other gas species, the absorption isotherms of CH4, N-2, and H-2 in pure PC and in 24%-mIm complex solvent with highest CO2 solubility were also measured. The results showed that the viscosities of these complex absorbents, as well as the solubility and heats of absorption of CO2 in all of them, moderately or slowly increased with an increase in mIm mass fraction, when the mIm content was lower than 20 wt%, and rapidly increased when it surpassed 20 wt%. The CO2 solubility could be more than doubled when the mIm content reached 24 wt% while viscosity and absorption heat still remains at low levels, that is, lower than 14 mPa.s and 26 kJ/mol, respectively. More importantly, the solubilities of CH4, N-2, and H-2 drastically decreased in the presence of mIm; using the 24 wt%-mIm complex absorbent instead of pure PC, the selectivity of CO2 over those other gas species increased by: 0.7-2.8 times for CH4, 3.9-6.3 times for N-2, and 3.5-7.7 times for H-2, with more significant improvements at lower pressure ranges. This work presents a very promising approach to PC washing technology upgrading.