离子液体脱除低浓度氯乙烯的实验与流程模拟

Experiment and process simulation for the removal of low concentration vinyl chloride by ionic liquids

为探究离子液体深度脱除尾气中氯乙烯的可行性,提出了离子液体高效吸收氯乙烯的技术.通过等体积饱和法测定了3种离子液体([BMPYR][Tf_(2)N],[BMIM][Tf_(2)N]和[EMIM][Tf_(2)N])对低浓度氯乙烯模拟气(5%)的饱和吸收量,并在填料塔中进行了超低浓度氯乙烯模拟气(0.01%)吸收实验,随后采用Aspen Plus流程模拟软件对离子液体吸收氯乙烯的工艺进行了概念设计和流程优化.结果表明,氯乙烯的亨利常数远低于氮气,且温度的影响较小.吸收塔的实验结果表明在25℃、常压、进气流速100mL/min的条件下,3种离子液体均可实现对超低浓度氯乙烯模拟气(0.01%)的高效捕集(吸收率>94%),其中[BMPYR][Tf_(2)N]表现出最大的吸收率97%.对[BMPYR][Tf_(2)N]吸收氯乙烯尾气(1%,进气流量100kg/h)的流程优化结果表明,在给定的最佳操作条件,即吸收塔板数为6,吸收塔相对压力为0.25MPa、吸收质流量2600kg/h、二级闪蒸罐温度为160℃、压力为0.001bar时,出口排放氯乙烯浓度能达到设定标准(0.0015%).研究表明离子液体可用于尾气中氯乙烯深度脱除,推广应用可降低尾气中有毒有害组分的污染.

The feasibility of deep vinyl chloride removal from tail gas was investigated by proposing the efficient absorption of vinyl chloride using ionic liquids(ILs).The saturation absorption of three types of ILs(i.e.,[BMPYR][Tf_(2)N],[BMIM][Tf_(2)N]and[EMIM][Tf_(2)N])on simulated vinyl chloride gas with a low concentration(5%)was measured using the equal volume saturation method,followed by an absorption experiment in a packed tower with simulated vinyl chloride gas at an extremely low concentration(0.01%).Subsequently,the concept design and process optimization of vinyl chloride absorption by ILs was performed using Aspen Plus process simulation software.The results indicate that the Henry constant of vinyl chloride is significantly lower than that of nitrogen,and the influence of temperature was relatively small.The experimental results of the absorption tower demonstrate that all the three ILs exhibited excellent removal performance(absorption ratio>94%)of vinyl chloride simulation gas with extremely low concentration(0.01%)under conditions of 25℃,atmospheric pressure,and inlet flow rate of 100mL/min.Among them,[BMPYR][Tf_(2)N]exhibited the highest absorption ratio at 97%.Process optimization results for[BMPYR][Tf_(2)N]absorbing vinyl chloride tail gas(1%,inlet flow rate of 100kg/h)reveal that under optimal operating conditions:number of theoretical plates for absorption tower of 6,a relative operating pressure of 0.25MPa,an IL absorption mass flow rate of 2600kg/h,as well as a temperature of 160℃and a pressure of 0.001bar for the secondary flash tank,the emitted concentration of vinyl chloride can meet the specified standard(0.0015%).The findings demonstrate that the utilization of ILs for efficient removal of vinyl chloride from exhaust gas and their extensive application can significantly contribute to mitigating the pollution caused by toxic and hazardous substances.