Novel CO2 Separation Process By Using Ionic Liquids

Novel CO₂ separation process by Using Ionic Liquids

Haifeng Dong, Suojiang Zhang*

Institute of Process Engineering, Chinese Academy of Sciences, 100190, Beijing, China

*Corresponding author: sjzhang@ipe.ac.cn

As a new solvent or medium, the unique structures and properties of ionic liquids make them show significant advantages in the reaction and separation fields. That offers new opportunities for new technology development and the breakthrough of reaction conditions ^[1]. Previously, we have done some interesting work for understanding the fundamental nature of ILs and developing new gas separation process. New task-specific ILs for CO₂ separation were designed and synthesized by modifying the structure of the anion and cation of the ILs. The CO₂ capture capacity of dual amino-functionalized ionic liquids is up to 18.5 wt%, which is obviously higher than previously reported amino- functionalized ILs ^[2]. Ionic-fragment method and corresponding states principle were proposed to develop predictive models for thermodynamic properties and phase equilibria of ILs system ^[3]. The effect of small amount of water on CO₂ bubble behavior in ionic liquid was investigated. The results indicated that a small amount of water has significant influence on the bubble behavior and mass-transfer coefficient in ionic liquids ^[4].

Based on simulated flue gas, continuous experiments were completed to evaluate the ionic liquids performance in the laboratory by using gas separation unit (1.0Nm³/h). Process simulation was also developed to optimize the CO₂ removal performance using pure ILs and ILs mixture. The results showed that ILs process saved about 31% regeneration heat energy consumption and 13.5% total capture cost compared to the monoethanolamine process^[5]. Next step, we hope to promote the engineering design and construction of demonstration equipments by cooperating with company.

Reference:

[1]      X. P. Zhang, X. C. Zhang, H. F. Dong, Z. J. Zhao, S. J. Zhang, Y. Huang. Carbon capture with ionic liquids: overview and progress. Energy Environ. Sci., 2012, 5, 6668

[2]      J. Z. Zhang, C. Jia, H. F. Dong, J. Q. Wang, X. P. Zhang, S. J. Zhang. A Novel Dual Amino- Functionalized Cation-Tethered Ionic Liquid for CO₂ Capture. Ind. Eng. Chem. Res., 2013, 52(17), 5835

[3]      Y. Huang, H. F. Dong, X. P. Zhang, C. S. Li, S. J. Zhang. A new fragment contribution- corresponding states method for physicochemical properties prediction of ionic liquids. AIChE J., 2013, 59(4), 1348

[4]      X. Zhang, H. F. Dong, D. Bao, Y. Huang, X. Zhang, S. J. Zhang. Effect of small amount of water on CO₂ bubble behavior in ionic liquid systems. Ind. Eng. Chem. Res. 2014, 53, 428-439.

[5]      Y. Huang, X. P. Zhang, H. F. Dong, X. Zhang, S. J. Zhang. Thermodynamic Modeling and Assessment of Ionic Liquid-based CO₂ Capture Processes, Ind. Eng. Chem. Res., 2014, 53 (29): 11805