Abstract Blended amine solvents are considered potential alternatives to monoethanolamine for CO2 capture, for the fast absorption kinetics of primary/secondary amine and low regeneration penalty of tertiary amine. In this research, blended amine solvents comprising N,N-dimethylcyclohexylamine (DMCA) and N-methylcyclohexyamine (MCA) were proposed. CO2 absorption increased the polarity of the products and ensured the absorbent remained homogenous throughout the absorption/desorption cycles. Through quantum chemical calculation, the low stability of MCA-carbamate was confirmed by a ΔΔG3 value of −6.41 kcal/mol, and a possible reaction route from carbamate to bicarbonate was revealed. Thus, the CO2 capacity of DMCA-MCA reached 0.875–0.985 mol CO2/mol amine. Moreover, MCA exhibited considerably low forward energy barrier for zwitterion formation (2.7 kcal/mol), and the CO2 absorption of DMCA could be accelerated through the proton transfer reaction with the MCA-zwitterion. Accordingly, the total mass transfer coefficient of CO2 in DMCA-MCA approached 2.02 × 10−10 mol/cm2 s Pa, which was 1.2-fold higher than that of 5 M MEA. The total regeneration energy of DMCA-MCA blend was estimated at 2.20 GJ/t CO2, which was 44.9% lower than 5 M MEA. This study developed a novel DMCA-MCA blended solvent with rapid absorption rate, huge CO2 capacity and efficient regeneration for CO2 capture.

中文翻译：

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N-甲基环己胺调控共混胺溶剂的CO2捕集性能及机理

摘要 由于伯/仲胺的快速吸收动力学和叔胺的低再生损失，混合胺溶剂被认为是单乙醇胺捕获 CO2 的潜在替代品。在本研究中，提出了包含 N,N-二甲基环己胺 (DMCA) 和 N-甲基环己胺 (MCA) 的混合胺溶剂。CO2 吸收增加了产品的极性并确保吸收剂在整个吸收/解吸循环中保持均匀。通过量子化学计算，通过-6.41 kcal/mol的ΔΔG3值证实了MCA-氨基甲酸盐的低稳定性，并揭示了从氨基甲酸盐到碳酸氢盐的可能反应路线。因此，DMCA-MCA 的 CO2 容量达到 0.875–0.985 mol CO2/mol 胺。此外，MCA 表现出相当低的两性离子形成前向能垒 (2. 7 kcal/mol)，并且通过与 MCA-两性离子的质子转移反应可以加速 DMCA 的 CO2 吸收。因此，DMCA-MCA 中 CO2 的总传质系数接近 2.02 × 10-10 mol/cm2 s Pa，比 5 M MEA 高 1.2 倍。DMCA-MCA 混合物的总再生能量估计为 2.20 GJ/t CO2，比 5 M MEA 低 44.9%。本研究开发了一种新型 DMCA-MCA 混合溶剂，具有吸收速度快、CO2 容量大、CO2 捕集再生高效。DMCA-MCA 混合物的总再生能量估计为 2.20 GJ/t CO2，比 5 M MEA 低 44.9%。本研究开发了一种新型 DMCA-MCA 混合溶剂，具有吸收速度快、CO2 容量大、CO2 捕获再生高效。DMCA-MCA 混合物的总再生能量估计为 2.20 GJ/t CO2，比 5 M MEA 低 44.9%。本研究开发了一种新型 DMCA-MCA 混合溶剂，具有吸收速度快、CO2 容量大、CO2 捕获再生高效。