Study On The Use Of Ionic Liquids For Trapping Volatile Organic Compounds In Thioethwes

Thioethers are a class of substances with distinctive characteristics in volatile organic compounds,which are frequently found in industrial production due to their special physicochemical properties.It can be used as a raw material for production and an important industrial product.However,it has low boiling point,volatility,irritating odor and toxicity.Therefore,thioether-containing waste gas generated by volatilization or other factors during use or production needs to be treated.In this paper,representative dimethyl sulfide(C2H6S)and dimethyl disulfide(C2H6S2)in thioethers were selected for research and analysis.In this paper,by comparing the characteristics of various VOCs removal methods,the ionic liquid with excellent characteristics is selected as the absorbent,and the absorption method is used to capture C2H6S and C2H6S2 in the gas.The feasibility of ionic liquids for C2H6S and C2H6S2 capture was explored through theoretical calculations,experiments and process simulations.In this paper,the COSMO-RS model is used to calculate the Henry's constant of N2,C2H6S and C2H6S2 in 240 ionic liquids,and the selectivity of these ionic liquids to N2/C2H6S and N2/C2H6S2 is further calculated.Then based on the Henry's constant and the selectivity data,considering the physicochemical properties of ionic liquids and other factors,the ionic liquid 1-ethyl-3 methyl-imidazole bistrifluoromethanesulfonimide salt([EMIM][Tf2N])was finally determined.as an absorbent for trapping C2H6S and C2H6S2 from nitrogen.At the same time,the COSMO-RS model was used to calculate the shielding charge distribution(?-profiles)of each component and the mixing enthalpy of[EMIM][Tf2N]with C2H6S and C2H6S2,respectively.From the molecular level,[EMIM][Tf2N]Capture the principles of C2H6S and C2H6S2.In order to further understand the mechanism of the[EMIM][Tf2N]capture process,this paper quantified and analyzed the system.The spatial configuration of[EMIM][Tf2N],N2,C2H6S and C2H6S2 were optimized by Gaussian software,and the binding energy of[EMIM][Tf2N]with N2,C2H6S and C2H6S2 were calculated to explore the strength of the combination between substances.The IGM calculation was performed using Multiwfn software to analyze the types and strengths of weak interaction forces between[EMIM][Tf2N]and N2,C2H6S and C2H6S2.Based on the results of theoretical calculations,the saturated vapor pressure values of the binary systems composed of C2H6S and C2H6S2 and[EMIM][Tf2N]were determined by static experiments.The experimental results were used to investigate the influence of the molar composition and temperature of the binary system on the saturated vapor pressure of the binary system,and verify the strength of[EMIM][Tf2N]on C2H6S and C2H6S2.At the same time,based on experimental data and literature data,the UNIFAC model group interaction parameters of each substance of the system were obtained.In this paper,the absorption packed column is used for absorption experiments to explore the actual effects of[EMIM][Tf2N]capture of C2H6S and C2H6S2,and the effect of[EMIM][Tf2N]flow on the capture effect.The Aspen Plus software was used to set the same experimental conditions and procedures for simulation analysis,and the reliability of the model was verified by comparing the experimental values with the simulated values.At the same time,the process design of industrial scale[EMIM][Tf2N]capture C2H6S,C2H6S2 process was also carried out.The effects of design parameters and operating parameters on the[EMIM][Tf2N]capture effect are explored,and the optimal parameters are obtained by optimizing each parameter.