In the face of increasing energy resource constraints,eco-environmental protection pressure,CO2 emission and high salt wastewater treatment become the focus of great concern.In this paper,CO2 was captured by organic amine method,desalination and conversion can be performed simultaneously by using bipolar membrane electrodialysis technology,changing Na Cl containing solution into Na OH,and combining with post capture CO2 to prepare Na HCO3,so as to realize the goal of CO2and high salt wastewater resource utilization simultaneously.The main content and conclusions of the study are as follows:(1)In the experiment of developing high-performance organic amine absorbent,the CO2 absorption and desorption properties of six common single-component organic amines,DETA,MDEA,DETA,AEP,PZ,AMP and MEA,were studied.The results show that increasing the concentration of-NH2 group in absorbent is more conducive to increasing the absorption capacity and absorption rate of CO2.Compared with other five organic amine absorbents,enamine DETA has a high number of amino groups in its molecular structure,showing excellent absorption performance,with the absorption capacity reaching 4.80 mol/L and the maximum absorption rate reaching 1.89×10-3 mol/Ls.Tertiary amine absorbent shows lower temperature requirement and lower desorption energy consumption,and tertiary amine MDEA shows good desorption performance,with desorption rate reaching 85.21%and maximum desorption rate reaching0.96×10-3mol/Ls.(2)On the basis of the performance research of single-component organic amine absorbent,the research of mixed amine absorbent was carried out.The CO2 absorption-desorption performance of MDEA+PZ,DETA+AEP,and DETA+MDEA composite system absorbent was systematically explored.The results showed that the absorption-desorption performances of 10%MDEA+30%PZ,30%DETA+10%AEP,and 30%DETA+10%MDEA were better.By comprehensively consider that absorption amount of CO2,the absorption rate,the desorption amount,the desorption rate,the desorption rate and the cycle stability,the results show that the performance of the mix amine absorbent with the ratio of 30 wt%DETA+10 wt%MDEA is optimal,The absorption amount of CO2 is 4.95mol/L,that maximum absorption rate is 2.65×10-3 mol/Ls,the desorption amount is 4.33 mol/L,the maximum desorption rate is 0.79×10-3 mol/ls,the desorption rate is 87.45%,which is 1.79 time,1.27 times,2.13 time,1.29 times and 1.19 times of that of the traditional 30 wt%MEA absorbent respectively,and in the next three absorption-desorption cycle experiments of the ratio,the absorption stability reaches 98.38%and the desorption stability reaches 97.23%.(3)In that acid and alkali preparation experiment of the Na Cl solution proces by the bipolar membrane electrodialysis device with the self-constructed membrane stack configuration of BP-A-C-BP three-compartment,it is found that the leakage of the acid chamber H+is the main reason for the decrease of the concentration in the alkali cham,and by improving the p H value of the solution in the material chamber,the concentration of Na OH in the alkali chamber and the conversion rate of Na Cl can be effectively increase.The optimal experimental conditions were as follows:current density was 35 m A/cm2,concentration of feed liquid was 2 mol/L,concentration of Na2SO4 in the polar chamber was 2g/L,initial acid-base concentration was 0.15 mol/L,and p H in the feed chamber was adjusted to 3.5.Under these conditions,1.78 mol/L HCl concentration,1.75 mol/L Na OH concentration and 96.88%,Na Cl conversion were obtained.(4)In the experiment of preparing Na HCO3 by CO2 continuous method coupled with the Na Cl solution treated by bipolar membrane electrodialysis,the conversion rate of Na Cl in the feed chamber reached97.68%,and the yield of Na HCO3 was relatively low due to the incomplete conversion of CO32-to HCO3-in the solution in the alkali chamber.The Na HCO3 was prepare by using that Na OH solution obtain after the Na Cl solution was treated by bipolar membrane electrodialysis technology and CO2 in a reaction kettle under normal pressure.the yield reach more than96%.compared with the Na HCO3 prepared by the continuous method,the segmented method has the advantages of high CO2 absorption rate,high Na HCO3 yield and the like.therefore,the segmented preparation of Na HCO3 is more economical and reasonable. |