四氢呋喃对离子液体水溶液二氧化碳水合物生成特性影响

摘要

为改善离子液体1-胺丙基-3-甲基咪唑溴([APMIm][Br])水溶液CO2水合物的生成特性,加入四氢呋喃(THF)形成复配溶液体系,研究复配体系中吸收CO2同时生成水合物的特性.建立可视化高压反应釜,在273.15-288.15 K、0.5-3.5 MPa条件下,测试了不同浓度的[APMIm][Br]和THF体系中水合物-溶液-CO2气体三相相平衡数据.实验结果表明:离子液体会抑制CO2水合物生成,而THF能有效促进离子液体水溶液CO2水合物的生成,水合物生成压力可大幅降低.基于离子液体水溶液缔合特性的活度系数模型理论和气体水合物的Vander Waals-Platteeuw模型理论,对复配溶液中CO2气体水合物的相平衡进行了计算,与实验值相比,平均相对误差为1.84％.复配溶液对低压二氧化碳表现出良好的溶液吸收和气体水合物生成双效捕获能力.%In order to ameliorate the formative properties of CO2 hydrate in the aqueous solutions of ionic liquid 1-aminopropyl-3-methyl-imidazolium bromide ([APMIm] [Br]),tetrahydrofuran (THF) was added.The properties of CO2 absorption in mixed aqueous solutions and formation of CO2 hydrate simultaneously were researched.In the temperature range of 273.15-288.15 K,pressure range of 0.5-3.5 MPa,three phase equilibrium of hydrate-solutions-CO2 gas in the system with different [APMIm] [Br] and THF concentrations were investigated in a high-pressure quartz glass reactor.The results showed that the formation of CO2 hydrate was inhibited by the [APMIm] [Br],but promoted effectively by the THF in the [APMIm] [Br] aqueous solutions,and the pressure for the formation of CO2 hydrate got reduced drastically.The activity coefficient model for the ionic liquid aqueous solutions and the Van der Waals-Platteeuw model for the gas hydrate were applied to calculate the phase equilibrium in the mixed aqueous solutions,and the average relative error was 1.84％ compared to the experiment data.The low-pressure CO2 capture performance of the double-effect process with CO2 absorption by solutions and formation of gas hydrate in the mixed aqueous solutions were well.