温度对离子液体支撑膜捕集CO_2的影响

Effect of temperature on CO_2 capture with the ionic liquid support membrane

传统CO_2的捕集方法存在设备投资大、环境污染严重、再生能耗高等缺点,利用新型绿色工质离子液体负载于聚偏氟乙烯上制备离子液体支撑膜可以较好地解决该问题。在压力为0.2 MPa、流量为50 m L·min-1、温度在298～318 K范围内变化时,测定了CO_2在1-乙基-3甲基咪唑双三氟磺酰亚胺盐([Emim][Tf_2N])和1-乙基-3-甲基咪唑醋酸盐([Emim][AC])2种离子液体支撑膜中的渗透系数、溶解度和扩散系数,采用Van’t Hoff方程对溶解度数据进行关联、Arrhenius方程对渗透和扩散系数的数据进行关联。实验结果表明,CO_2在2种离子液体支撑膜中的渗透和扩散系数随着温度的升高而增大,溶解度随着温度的升高而降低。[Emim][Tf_2N]离子液体支撑膜对CO_2的捕集性能优于[Emim][AC]支撑膜,CO_2在[Emim][Tf2N]支撑膜中的溶解度最大值为0.447,在[Emim][AC]离子液体支撑膜中的最大溶解度为0.253,由此可确定离子液体支撑膜分离CO_2的最佳工作温度,为其在工业应用中奠定良好的基础。

Traditional CO2capture methods have disadvantages,such as large investment in equipment,serious environmental pollution,and high regeneration energy consumption etc.The preparation of ionic liquid supporting film by a new type of green working ionic liquid loaded on PVDF can solve this problem.The permeability coefficient,solubility and diffusion coefficient of CO2in two kinds of ionic liquid supporting membranes of 1-ethyl-3 methimidazole bisthree fluorosulfonimide salt [Emim][Tf2N]and 1-ethyl-3-methyl imidazole acetate [Emim][AC]were measured at the pressure of 0.2MPa,the flow rate of 50mL.min^-1,and the temperature range of 298~318K.The Van't Hoff equation was used to correlate the solubility data,and the Arrhenius equation was used to correlate the permeability coefficient and diffusion coefficient data.The experimental results showed that with the increase of temperature,the permeability and diffusion coefficient increased,while the solubility decreased.The CO2capture performance of [Emim][Tf2N]ionic liquid supporting membrane was better than [Emim][AC]supporting membrane,and the maximum CO2solubility in [Emim][Tf2N]and [Emim][AC]supporting membranes was 0.447and 0.253,respectively.Then the optimum working temperature for CO2separation by ionic liquid supporting membrane can be determined accordingly,which lays a good foundation for its industrial application.