Non-aqueous absorbents receive more and more attention due to their low sensible heat and evaporation latent heat. But their low CO₂ desorption efficiency and high desorption reaction heat are still major limits for practical application. Herein, a novel non-aqueous diamine absorbent based on alkanolamine regulation is proposed. In the experiments, monoethanolamine (MEA) was used as the main absorbent for ensuring high CO₂ absorption capacity and absorption rate, while polyethylene glycol 200 (PEG200) was used as a cosolvent to reduce evaporation latent heat. Subsequently, MEA/PEG200 non-aqueous absorbents were composed with three typical secondary/tertiary amines including N-methyldiethanolamine (MDEA), diethanolamine (DEA) and triethanolamine (TEA), respectively, and their regulation effects on CO₂ capture performance were investigated systematically. The results showed that the MEA/MDEA/PEG non-aqueous system exhibited a superior CO₂ desorption performance. The corresponding maximum regeneration efficiency reached up to 82.1%, which was significantly higher than the case without addition of MDEA. It still kept a high CO₂ desorption efficiency (79%) after the 8th regeneration cycle. According to thermodynamic analysis, the desorption reaction heat for the MEA/MDEA/PEG non-aqueous system was only 1.40 GJ per ton CO₂, which was 20% lower than the non-aqueous MEA/PEG200 absorbent. And its total regeneration energy consumption was 1.90 GJ per ton CO₂, which was reduced by 48.1% compared to MEA aqueous solution. FT-IR, ¹³C-NMR and DFT calculations indicated that the introduction of the MDEA regulator would result in a much lower reaction energy barrier between zwitterions and MDEA compared to that between zwitterions and MEA. Besides, it would induce the formation of protonated MDEA (MDEAH⁺), which was much easier for MDEA regeneration.

中文翻译：

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一种基于 N-甲基二乙醇胺调节的新型二胺非水吸收剂，用于高效节能的二氧化碳捕获

非水吸收剂由于其较低的显热和蒸发潜热而受到越来越多的关注。但其低CO ₂解吸效率和高解吸反应热仍然是实际应用的主要限制。在此，提出了一种基于烷醇胺调节的新型非水二胺吸收剂。实验中，采用单乙醇胺(MEA)作为主要吸收剂，以保证较高的CO ₂吸收能力和吸收率，同时采用聚乙二醇200(PEG200)作为助溶剂，以降低蒸发潜热。随后，分别与N-甲基二乙醇胺(MDEA)、二乙醇胺(DEA)和三乙醇胺(TEA)三种典型仲胺/叔胺组成MEA/PEG200非水吸收剂，系统研究了它们对CO ₂捕集性能的调节作用。 。结果表明MEA/MDEA/PEG非水体系表现出优异的CO ₂解吸性能。相应的最大再生效率达到82.1%，明显高于不添加MDEA的情况。第8次再生循环后仍保持较高的CO _{2解吸效率(79%)。}热力学分析表明，MEA/MDEA/PEG非水体系解吸反应热仅为1.40 GJ/吨CO ₂，​​比非水MEA/PEG200吸收剂低20%。_{其再生总能耗为每吨CO 2} 1.90GJ ，比MEA水溶液降低48.1%。FT-IR、¹³ C-NMR 和 DFT 计算表明，MDEA 调节剂的引入将导致两性离子和 MDEA 之间的反应能垒比两性离子和 MEA 之间的反应能垒低得多。^{此外，它会诱导质子化MDEA（MDEAH +} ）的形成，这更容易MDEA再生。