【作者】 李红；

【导师】 张永春；

【作者基本信息】 大连理工大学 ， 化学工程（专业学位）， 2021， 硕士

【摘要】 比较了九种不同配方醇胺溶液对CO₂的吸收解吸性能。其中,N-乙基乙醇胺（EMEA）+二乙氨基乙醇（DEEA）+哌嗪（PZ）和2-氨基-2-甲基-1,3丙二醇（AMPD）+哌嗪（PZ）+水（H₂O）两种溶液的吸收解吸的稳定性最佳,溶剂的两次平均解吸率在94.00%以上。对溶液进行144 h热降解和96 h氧化降解,结果表明热降解后的EMEA+DEEA+PZ溶液的吸收解吸性能稳定性较高,溶液平均吸收量、平均解吸量略有升高,分别升高了1.58L CO₂/kg solution,0.35 L CO₂/kg solution,平均解吸率下降2.04%;而氧化降解造成平均吸收量、平均解吸量分别下降0.45 L CO₂/kg solution、1.75 L CO₂/kg solution,平均解吸率下降2.25%;热降解对于AMPD+PZ+H₂O溶液吸收解吸性能影响较大,热降解实验造成溶液平均吸收量、平均解吸量分别下降5.63 L CO₂/kg solution,4.03 L CO₂/kg solution,平均解吸率分别升高2.32%,在经过氧化降解之后,溶液的平均吸收量、平均解吸量分别下降1.05 L CO₂/kg solution,0.70 L CO₂/kg solution,平均解吸率分别升高0.59%。液质联用分析结果表明,热降解导致EMEA浓度减少19.67%,AMPD浓度减少71.89%;氧化降解导致EMEA浓度减少18.18%,AMPD浓度减少74.53%。热降解以及氧化降解实验结果表明:EMEA+DEEA+PZ比AMPD+PZ+H₂O具有更好的抗降解性能。根据电喷雾质谱结果对两种溶液的热降解、氧化降解的机理进行推测,热降解中生成恶唑烷酮类物质,氧化降解则是生成酸类物质。在研究金属离子对于EMEA+DEEA+PZ降解的影响实验结束后发现,在热降解与氧化降解过程中,添加了金属离子使电导率高于未加入金属离子的溶液。氧化降解实验过程中,加入Fe³⁺的溶液的粘度在降解过程中粘度始终低于另外三种溶液。在热降解过程中,加入Fe³⁺和加入Ni²⁺的EMEA+DEEA+PZ溶液的最终的粘度略低于最初溶液的粘度。在氧化降解过程中,加入金属离子使胺浓度下降更多。在热降解过程中,加入Fe³⁺、Cr³⁺会使胺浓度下降更多。加入Fe³⁺会加强热降解对于EMEA+DEEA+PZ溶液在吸收解吸性能方面的负影响,加入Ni²⁺、Cr³⁺对于热降解后的EMEA+DEEA+PZ溶液的吸收解吸性能影响不大。加入Fe³⁺会影响氧化降解后的EMEA+DEEA+PZ溶液的解吸性能,加入Ni²⁺会影响氧化降解后的EMEA+DEEA+PZ溶液的吸收解吸性能的稳定性,加入Cr³⁺会降低氧化降解对于EMEA+DEEA+PZ在吸收解吸性能方面的负影响。在AMPD+PZ+H₂O溶液中加入己二胺,可以有效减少溶液中AMPD浓度的降低程度,而加入二异丙醇胺、咪唑会使AMPD的浓度降低程度加重。在AMPD+PZ+H₂O中加入己二胺可以有效提高溶液的抗热降解性能。更多还原

【Abstract】 The CO₂ absorption and desorption performances of nine alcohol amines were compared.Among them,there were two kinds of solutions that showed the better stability of absorption-desorption performance,which contained N-ethylethanolamine（EMEA）+dieth-ylaminoethanol（DEEA）+piperazine（PZ）and 2-amino-2-methyl-1,3-propanediol（AMPD）+piperazine（PZ）+H₂O.The average desorption rate of the solvents were above 94.00%after two cyclic tests.The solutions were subjected to thermal degradation for 144 h and oxidative degradation for 96 h.It was found that the absorption-desorption performance of EMEA+DEEA+PZ solution after thermal degradation was stable.The average absorption amount and desorption amount of the solution increased slightly by 1.58 L CO₂/kg solution and 0.35 L CO₂/kg solution,respectively,and the average desorption rate decreased by 2.04%.While oxidative degradation caused the average absorption amount and desorption amount to decrease by 0.45 L CO₂/kg solution and 1.75 L CO₂/kg solution,respectively,and the average desorption rate decreased by 2.25%.The thermal degradation had a distinct impact on the absorption-desorption performance of AMPD+PZ+H₂O solution,which caused a decrease in the average absorption amount and desorption amount of the solution by 5.63 L CO₂/kg solution and 4.03 L CO₂/kg solution,respectively,and the average desorption rate increased by 2.32%.After oxidative degradation,the average absorption amount and desorption amount of the solution decreased by 1.05 L CO₂/kg solution and 0.70 L CO₂/kg solution,respectively,and the average desorption rate increased by 0.59%.The results of the liquid mass spectrometry analysis showed that the concentrations of EMEA and AMPD decreased by19.67%and 71.89%due to thermal degradation,18.18%and 74.53%due to oxidative degradation,respectively.The results of thermal and oxidative degradation experiments demonstrated that EMEA+DEEA+PZ had the better anti-degradation performance than AMPD+PZ+H₂O.The mechanisms of thermal and oxidative degradation of the two kinds of alcohol amines were speculated based on the results of electrospray mass spectrometry,in which oxazolidinones were generated in thermal degradation and acids were generated in oxidative degradation.In both cases,oxidative degradation had negative effects on both solutions,while thermal degradation did not.At the end of the experiments to study the effect of metal ions on the degradation of EMEA+DEEA+PZ,it was found that the conductivity of the solutions with Fe³⁺,Ni²⁺,and Cr³⁺were higher than that of the solution without metal ions during thermal and oxidative degradation.During the oxidative degradation experiments,the viscosity of the solution with Fe³⁺was always lower than the other three solutions of EMEA+DEEA+PZ solution without metal ions and with Ni²⁺and Cr³⁺during the degradation process.During thermal degradation,the final viscosity of the EMEA+DEEA+PZ solution with Fe³⁺and Ni²⁺was slightly lower than that of the initial solution.During oxidative degradation,the concentration of EMEA in the EMEA+DEEA+PZ solution without metal ions and with the Fe³⁺、Ni²⁺、Cr³⁺decreased by18.18%,29.51%,50.87%,and 49.63%,respectively,the addition of metal ions decreased more the amine concentration.During thermal degradation,the concentration of EMEA in the EMEA+DEEA+PZ solution without metal ions and with the Fe³⁺,Ni²⁺,and Cr³⁺decreased by22.26%,33.66%,22.14%,and 28.44%,respectively,and the addition of Fe³⁺and Cr³⁺decreased more concentration of amine.The addition of Fe³⁺strengthens the negative effect of thermal degradation on the absorption-desorption performance of EMEA+DEEA+PZ solution after thermal degradation,and the addition of Ni²⁺and Cr³⁺has little influence.The addition of Fe³⁺affects the desorption performance of EMEA+DEEA+PZ solution after oxidative degradation,the addition of Ni²⁺affects the stability of the absorption and desorption performance of EMEA+DEEA+PZ solution after oxidative degradation,and the addition of Cr³⁺weakens the negative effect of oxidative degradation on EMEA+DEEA+PZ in terms of absorption and desorption performance.The addition of hexanediamine to AMPD+PZ+H₂O solution can effectively reduce the degree of reduction of AMPD concentration in the solution,while the addition of diisopropanolamine and imidazole will strengthen the degree of reduction of AMPD concentration.The addition of hexanediamine to AMPD+PZ+H₂O could effectively improve the thermal degradation resistance of the solution.更多还原