离子液体和醇胺溶液复配脱硫剂吸收H2S及再生性能

将5种离子液体[Bmim]HCO₃, [TMG]L, [MEA]L, [Bmim]Cl和[Bmim]BF₄分别与N-甲基二乙醇胺(MDEA)水溶液混合, 得到新型复配脱硫剂, 考察了离子液体的消泡性能和复配脱硫剂在不同离子液体、 吸收温度以及复配比例下的脱硫性能, 并且对较优脱硫剂进行了再生性能的研究. 采用离子色谱仪对经臭氧深度处理的再生液进行了S\begin{array}{c}{O}_4^{2-}\end{array}离子浓度测试, 并对脱硫剂进行了密度泛函理论研究, 从而进一步分析了吸收机理. 结果表明, 室温下复配脱硫剂脱硫能力大小顺序为[Bmim]Cl-MDEA-H₂O>[Bmim]HCO₃-MDEA-H₂O>[Bmim]BF₄-MDEA-H₂O>MDEA-H₂O>[TMG]L-MDEA-H₂O>[MEA]L-MDEA-H₂O. 离子液体与MDEA结合的稳定性为主要影响因素, [Bmim]HCO₃的消泡能力最强, [Bmim]Cl-MDEA-H₂O, [Bmim]BF₄-MDEA-H₂O和[Bmim]HCO₃-MDEA-H₂O脱硫剂可以通入空气获得基本再生, H₂S与离子液体的结合越稳定, 脱硫效率越高, 但脱硫剂的再生程度会降低.

H2S Absorption Capacity of Ionic Liquid-MDEA-H2O Combined Desulfurizers†

Three kinds of functionalized ionic liquids [Bmim]HCO₃, [TMG]L and [MEA]L were synthesized. The structure and thermostability of the synthetic ionic liquids(ILs) were confirmed by FTIR spectrum and thermogravimetry characterization, respectively. The new combined desulfurizers were prepared by mixing ionic liquid([Bmim]HCO₃, [TMG]L, [MEA]L, [Bmim]Cl or [Bmim]BF₄) with methyldiethanolamine(MDEA) aqueous solution according to certain proportion. Under conditions of different ionic liquids, absorption temperature and desulfurizer composition, H₂S absorption and bubble eliminating capacity of the desulfurizer were measured, and regeneration performance of the favorable desulfurizer was studied. The concentration of S\begin{array}{c}{O_4}^{2-}\end{array} in regenerated desulfurizer was analyzed by ion chromatography after deep oxidation by O₃, and the mechanism of absorption was analyzed based on the calculations from density functional theory. The results show that absorption capacity is in the sequence of [Bmim]Cl-MDEA-H₂O>[Bmim]HCO₃-MDEA-H₂O>[Bmim]BF₄-MDEA-H₂O>MDEA-H₂O>[TMG]L-MDEA-H₂O>[MEA]L-MDEA-H₂O, and the major factor is attributed to the stability of IL-MDEA; [Bmim]HCO₃ performs the best capacity of bubble elimination; [Bmim]Cl-MDEA-H₂O, [Bmim]HCO₃-MDEA-H₂O and [Bmim]BF₄-MDEA-H₂O can be nearly completely regenerated by air, and high stability of IL-H₂S leads to higher absorption efficiency, but smaller extent of regeneration.