胍类氨基酸离子液体捕集烟气中CO_(2)实验研究

Experimental study on the capture of CO_(2) in flue gas by guanidine amino acid ionic liquids

目的通过开展胍类氨基酸离子液体捕集烟气中CO_(2)性能研究实验,找到吸收性能好、溶剂损失少和能耗低的新型CO_(2)吸收剂。方法以四甲基胍(TMG)为阳离子,赖氨酸(Lys)、丙氨酸(Ala)和天冬氨酸(Asp)为阴离子,制备了[TMG][Lys]、[TMG][Ala]和[TMG][Asp]3种低黏度胍类氨基酸离子液体,并对其脱碳性能进行评价。结果碱性较大的[TMG][Lys]具有较高CO_(2)吸收量,在常压、45℃、80 mL/min的条件下,吸收量为0.64 mol CO_(2)/mol IL。水的加入对CO_(2)的吸收有积极的影响,30%(w)[TMG][Lys]水溶液的吸收量增加到0.99 mol CO_(2)/mol IL,且经过5次吸收-解吸循环后仍能达到0.81 mol CO_(2)/mol IL。通过傅里叶红外光谱(FT-IR)、核磁共振氢谱(1H-NMR)对[TMG][Lys]的脱碳机理进行分析,CO_(2)主要通过与阴离子上的氨基反应生成氨基甲酸酯,以实现对烟气中CO_(2)的高效捕集。结论该研究可为工业CO_(2)捕集高效低耗吸收剂的开发提供参考。

Objective In order to find a new absorbent with good absorption performance,low solvent loss,and low energy consumption for CO_(2) capture,the preparation and performance of guanidine amino acid ionic liquids to capture CO_(2) in flue gas was investigated.Methods Three kinds of guanidine amino acid ionic liquids with low viscosity,namely[TMG][Lys],[TMG][Ala],and[TMG][Asp],were prepared using tetramethylguanidine(TMG)as a cation and lysine(Lys),alanine(Ala),and aspartic acid(Asp)as anions.The effects of anionic types on CO_(2) absorption were investigated.Results The alkaline[TMG][Lys]had a higher CO_(2) absorption,with a CO_(2) absorption capacity of 0.64 mol CO_(2)/mol IL under the condition of atmospheric pressure,45℃,and 80 mL/min.The addition of water had a positive effect on the absorption of CO_(2).The absorption capacity of 30 wt%[TMG][Lys]aqueous solution increased to 0.99 mol CO_(2)/mol IL and could still keep 0.81 mol CO_(2)/mol IL after 5 absorption-desorption cycles.The decarbonization mechanism of[TMG][Lys]was analyzed by Fourier transform infrared spectroscopy(FT-IR)and nuclear magnetic resonance hydrogen spectroscopy(1H-NMR).CO_(2) mainly reacts with the amino group on the anion to form carbamate to achieve efficient capture of CO_(2) in the flue gas.Conclusions It can provide reference for the development of new absorbents in industrial CO_(2) capture.