关键词: 碳捕获, 气体水合物, 离子液体, 水溶液

Abstract: Double-capture process of CO2 with CO2 absorption in aqueous solution of ionic liquid 1-aminopropyl-3-methylimidazolium bromide ([APMIM]Br) and simultaneous formation of CO2 gas hydrate was designed. Based on the experimental data of CO2 solubility and phase equilibrium data of CO2 hydrate formation in [APMIM]Br aqueous solution, the mass balance of this process under various working conditions were calculated, the effects of water concentration, pressure and liquid gas flow ratio on the CO2 capture rate examined, and the comparative performances of CO2 gas hydrate capture and CO2 absorption by the ionic liquid solution in the process also studied. The results show that at high pressure and high water content, the CO2 capture performance by gas hydrate formation is comparatively higher than that of the absorption by ionic liquid solution, while at lower pressure, the absorption of the aqueous solution plays a major role. The CO2 capture performance of the double-effect process with CO2 absorption plus hydrate formation in the aqueous solution is superior to that of CO2 gas formation in pure water system. When molar content of CO2 in feed gas is less than 65%, the CO2 capture rate of double-capture process is less than 40%. For the feed gas with lower CO2 content, the process approaches to the pure absorption process with the ionic liquid aqueous solution.

Key words: CO2 capture, gas hydrate, ionic liquid, aqueous solution