Analysis of the changes in the absorption and regeneration performance of diethylenetriamine in carbon capture environments with functionalized alcohols and mixed amines

• Published in: Fuel (Guildford) Vol. 368; p. 131375
• Main Authors: Jin, Lijian, Hou, Xueyan, Zhan, Lingxiao, Hou, Dawei, Gu, Lina, Zhang, Daguang, Shen, Jianchong, Zheng, Zhihao, Lv, Chao, Liu, Shaoqing, Yang, Linjun
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 15.07.2024
• Subjects: DFT; Functional groups; Hydrophobicity; Mixed amines; Molecular dynamics; Molecular dynamics; Mixed amines; DFT; Hydrophobicity; Functional groups
• ISSN: 0016-2361; 1873-7153
• DOI: 10.1016/j.fuel.2024.131375

[Display omitted] •The interaction between the -Cl functional group and the amino group is detrimental to carbon capture and phase separation.•Calculation of the reaction mechanism of mixed amines with CO2.•Classical molecular dynamics reveals the effect of functional groups on intermolecular forces.•Analysis of the impact of log P values on the absorption and regenerative performance of absorbents. Biphasic solvents significantly reduce the energy consumption of CO2 capture processes due to their phase separation behavior. In this investigation, the effects of six absorption accelerators and five phase splitters (alcohols) on the CO2 absorption, CO2 desorption and phase separation performance of biphasic solvents were evaluated. In addition to the phase splitter being 3-chloro-1-propanol, the higher the hydrophobicity (log P) of the phase splitter, the better the absorbent phase separation performance. The phase splitting behavior of the absorbent changes the carbon capture environment of the amine, and the new carbon capture environment is not conducive to the reaction between the amine and CO2, therefore, a phase splitter with a lower log P can improve the CO2 loading of the absorbent. The CO2 desorption performance of the absorbent was significantly enhanced by the presence of more alcohols in the rich phase. Diethylenetriamine (DETA) reacts with CO2 to produce a product with the largest dipole moment, which is suitable for the phase separation of various mixed amines. Synergistic effects between 2-Aminoethanol (MEA) and DETA are evident, as the partial substitution of DETA with MEA yields no substantial changes in phase separation performance. To better understand the effects of mixed amines and phase splitter on the CO2 uptake and phase separation behavior of biphasic solvents, the present study carried out density-functional theory (DFT) calculations and molecular dynamics (MD) simulations, to analyse in depth the effects of different functional groups on the intermolecular forces, the CO2 absorption mechanism and synergistic effects between mixed amines. This study was carried out to analyse in detail the effects of different functional groups on the intermolecular forces, and the mechanism of CO2 absorption between mixed amines and the synergistic effects.