为了达到快速筛选相变吸收剂的目的,基于汉森溶解度参数理论,以N-甲基二乙醇胺(MDEA)为主吸收剂,有机溶剂为分相促进剂,水为溶剂,快速筛选出一种新型相变吸收剂———MDEA/聚乙二醇二甲醚(NHD)/H2O。热重分析(TGA)测试了相变吸收剂的热稳定性,CO2吸收、解吸试验探究了相变吸收剂的CO2吸收性能、解吸性能及循环再生能力。1HNMR测试了相变前后物质的分布情况。结果表明,MDEA/NHD/H2O相变吸收剂相比质量分数30%乙醇胺(MEA)吸收剂及文献已报道的MDEA/正丁醇/H2O相变吸收剂具有最高的热稳定性。NHD作为分相促进剂的同时可促进CO2在相变吸收剂中的溶解,MDEA/NHD/H2O相变吸收剂发生液-液分相需要NHD和H2O同时存在。25℃时,质量比为3∶5∶2的MDEA/NHD/H2O相变吸收剂具有最高CO2吸收容量为1.0695mol/L。所开发的相变吸收剂可将送至解吸单元的解吸液体积降至42%。在解吸温度90℃时,CO2解吸效率达98.96%。在25℃下吸收,90℃下热解吸,经10次吸收、解吸循环再生试验,质量比为3∶5∶2的MDEA/NHD/H2O相变吸收剂的CO2总循环容量为9.2604mol/L,相比于质量分数30%MEA吸收剂、30%MDEA吸收剂及MDEA/正丁醇/H2O相变吸收剂具有最高的CO2循环能力。1HNMR测试结果表明该相变吸收剂的上液相主要成分为NHD,为贫液相。下液相主要成分为MDEA和MDEAH+,为富液相。

To achieve the purpose of rapid screening of phase change absorbent, a new phase change absorbent-MDEA/ polyethylene glycoldimethyl ether (NHD) / H2O was quickly screened with N-methyl diethanolamine (MDEA) as the main absorbent, organic solvent as thephase separation accelerator and water as the solvent, guided by the theory of Hansen solubility parameter. The thermal stability of thephase change absorbent was tested by thermogravimetric analysis ( TGA), and the CO2 absorption and desorption performance of thephase change absorbent was investigated by CO2 absorption and desorption experiments, as well as the recycling ability.1HNMR was usedto test the distribution of the substances before and after the phase change. The results show that MDEA/ NHD/ H2O phase change absorbent has the highest thermal stability compared with 30% ethanolamine (MEA) absorbent and MDEA/ n-butanol/ H2O phase change absorbent reported in the literature. NHD as a phase separation accelerator can promote the dissolution of CO2 in the phase transition absorbent, MDEA/ NHD/ H2O phase transition absorbent liquid-liquid phase separation requires the coexistence of NHD and H2O. At the absorption temperature of 25 ℃ , the MDEA/ NHD/ H2O phase change absorbent with a mass ratio of 3 ∶ 5 ∶ 2 has the highest CO2 absorption capacity of 1.069 5 mol/ L. The phase change absorbent developed in this paper can reduce the volume of desorption liquid sent to thedesorption unit to 42%. The CO2 desorption efficiency reached 98.96% at a desorption temperature of 90 ℃ . The total CO2 cycling capacity of MDEA/ NHD/ H2O phase change absorbent with a mass ratio of 3 ∶ 5 ∶ 2 was 9.260 4 mol/ L after 10 cycles of absorption at 25 ℃and thermal desorption at 90 ℃ . Compared with 30% MEA absorbent, 30% MDEA absorbent and MDEA/ n-butanol / H2O phase changeabsorbent, it has the highest CO2 cycling capacity. The 1HNMR test results showed that the upper liquid phase of the phase change absorbent was mainly composed of NHD, which was a CO2-lean phase. The lower liquid phase is mainly composed of MDEA and MDEAH+,which is a CO2-rich phase.

0 引言

1 试验

   1.1 试剂与仪器

   1.2 试验流程

2 结果与讨论

   2.1 MDEA/NHD/H2O相变吸收剂CO2吸收试验

   2.2 相变吸收剂的热稳定性

   2.3 MDEA/NHD/H2O相变吸收剂CO2解吸试验

   2.4 相变吸收剂两相物质分布

3 结论