混合醇胺溶液耦合电石炉净化灰吸收-矿化CO_(2)性能

Absorption-mineralization performance of CO_(2) by mixed alcohol amine solution coupled with purified dusts from calcium carbide furnace

针对醇胺吸收法中富CO_(2)吸收液的解吸封存问题,详细探究了乙醇胺(MEA)与N,N-二甲基乙醇胺(DMEA)混合溶液耦合电石炉净化灰吸收-矿化CO_(2)的潜力,并同等添加比例(n(CO_(2)):n(Ca)=1.0:1.0)下CaO、Ca(OH)_(2)的CO_(2)矿化性能进行了对比。实验结果表明,配比为1.5 mol/LMEA+1.5 mol/LDMEA的混合醇胺溶液的CO_(2)吸收负荷和解吸率最大,分别为1.807mol/L和82.78%;经过4次吸收-解吸循环后其CO_(2)吸收性能有所下降,但4次循环后CO_(2)吸收负荷仍有0.950 mol/L,利用电石炉净化灰可有效解吸封存MEA/DMEA混合醇胺溶液吸收的CO_(2)。电石炉净化灰的解吸性能接近CaO但优于Ca(OH)_(2),所得矿化产物包括文石、球霰石和方解石型碳酸钙。这主要由于活性含钙物质可以向富CO_(2)溶液中释放Ca^(2+)和OH^(-),继而同溶液中CO_(3)^(2-)和HCO_(3)^(-)反应生成CaCO_(3)沉淀,并中和质子化胺MEAH+/DMEAH+,同时实现CO_(2)矿化和混合醇胺溶液的再生。

To address the problem of desorption and sequestration of CO_(2)-rich absorption solution in the alcoholamine absorption method,the potential of absorption-mineralization of CO_(2) from mixed solution of ethanolamine(MEA)and N,N-dimethylethanolamine(DMEA)which coupled with purified dusts from calcium carbide furnace was investigated in detail.And the CO_(2) mineralization performance of this purified dust was compared with that of CaO and Ca(OH)_(2) at an equal adding proportion(n(CO_(2)):n(Ca)=1.0:1.0).The experimental results show that the CO_(2) absorption loads and desorption rate are the largest with the 1.5 mol/L MEA+1.5 mol/L DMEA mixed solution,which are respectively 1.807 mol/L and 82.78%.The CO_(2) absorption performance decreases after four absorption-desorption cycles,but still has the CO_(2) absorption loads of 0.950 mol/L.The CO_(2) absorbed by MEA/DMEA mixed solution can be effectively desorbed and stored by purified dusts from calcium carbide furnace.The desorption performance of purified dusts from calcium carbide furnace for CO_(2) rich solution is similar to that of CaO but better than that of Ca(OH)_(2).The mineralization products consist three types of calcium carbonate which are aragonite,sphalerite and calcite.This is mainly due to the fact that the active calcium-containing components can release Ca^(2+)and OH^(-)into the CO_(2) rich solution,and then they react with CO_(3)^(2-) and HCO_(3)^(-) in the solution to form CaCO_(3),neutralize the protonated amine MEAH+/DMEAH+.Finally,CO_(2) mineralization and alcoholamine solution regeneration are achieved simultaneously.