Self-diffusion coefficients in the process of carbon capture by amine solvents based on molecular dynamics simulation

doi:10.16085/j.issn.1000-6613.2025-0068

Abstract

Abstract:

Chemical absorption is one of the most widely used CO₂ capture methods, and amine solvent chemical absorption technology is more mature. The amine solvent carbon capture process is a typical chemical process with the characteristics of “three transfers and one inversion”. In this process, the diffusion coefficient is an important parameter for evaluating the mass transfer process, and it also affects the kinetic performance evaluation and the reaction performance evaluation of CO₂ absorption by amine solvents. In this study, the simulation accuracy of the traditional solvent molecular force field model was found to be low. To ensure the accuracy of the simulation, the solvent force-field model was first modified, and the results showed that the modified force-field model could accurately describe the intermolecular interactions and self-diffusion coefficients in the solvent of N-Methyldiethanolamine (MDEA), and the prediction error was less than 3%. Then, based on this model, the self-diffusion coefficients of other monoamine solvents [monoethanolamine (MEA), diethanolamine (DEA), etc.] were calculated, and the quantitative relationship between the self-diffusion coefficients and temperature was deduced. On the other hand, in order to explore the influence of ions generated during the reaction process on the kinetic properties of amine solvent, the simulation systems under different reaction progress were constructed. The findings of the study indicated a gradual decrease of the self-diffusion coefficient during the reaction process, with a concomitant linear relationship between the coefficient and the reaction progress. Furthermore, the simulation of mixed amine solvents (e.g. MEA and MDEA) at varying proportions demonstrated that the self-diffusion coefficient exhibited a linear relationship with the mass fraction of MEA. Through further analysis of the intermolecular interaction energy and radial distribution function, the variation rule of the amine solvent self-diffusion coefficient and its microscopic mechanism were explained. In conclusion, this study modified the force field model and provided important theoretical support and simulation tools for optimizing the CO₂ capture performance of amine solvents.

Key words: CO₂ capture, amine solvent, molecular dynamics, dynamic properties, mass transfer, molecular simulation, reaction progress

摘要：

化学吸收法是当前广泛应用的CO₂捕集方法之一，而采用胺溶剂进行化学吸收的技术较为成熟。胺溶剂碳捕集过程是典型具备“三传一反”特性的化工过程。在这一过程中，扩散系数是评估其传质过程的重要参数，同时影响着胺溶剂吸收CO₂过程中的动力学性能评价和反应性能评价。由于传统的实验方法测量胺溶剂扩散系数较为烦琐，本文采用分子动力学模拟的方法进行研究。首先，研究发现通用小分子力场模型（PCFF）在胺溶剂水溶液体系下的模拟精度较低，为确保模拟的准确性，需要针对分子力场模型进行修正。结果表明，修正后的力场模型能准确描述甲基二乙醇胺（MDEA）溶剂中的分子间相互作用和自扩散系数，预测误差小于3%。随后，基于修正模型，本文计算了多种单胺溶剂的自扩散系数，并推导了自扩散系数与温度之间的定量关系。为探明胺溶剂动力学性质受反应进度变化产生的离子的影响，研究构建了不同反应进度下的模拟体系。基于结果，研究发现自扩散系数在反应过程中逐渐减小，且与反应进度呈线性关系。此外，对不同比例混合胺溶剂（如单乙醇胺与甲基二乙醇胺）的模拟显示，自扩散系数与MEA的质量分数近似呈线性关系。通过对分子间相互作用能和径向分布函数的进一步分析，本文阐明了胺溶剂自扩散系数的变化规律及其微观机制。综上，本文针对通用小分子力场模型进行了修正，并为优化胺溶剂的CO₂捕集性能提供了重要的理论支持和模拟工具。

关键词: 二氧化碳捕集, 胺溶剂, 分子动力学, 动力学性质, 传质, 分子模拟, 反应进度

CLC Number:

TQ413.26

HUANG Ke’er, LIU Jiahao, LI Haoming, ZHOU Tianhang, GAO Jinsen, LAN Xingying. Self-diffusion coefficients in the process of carbon capture by amine solvents based on molecular dynamics simulation[J]. Chemical Industry and Engineering Progress, 2025, 44(8): 4352-4364.

黄可儿, 刘佳豪, 李昊明, 周天航, 高金森, 蓝兴英. 基于分子动力学模拟的胺溶剂碳捕集过程自扩散系数[J]. 化工进展, 2025, 44(8): 4352-4364.

Figures/Tables 20

项目	288K	298K	308K
未修正力场结果/10^-10m²·s^-1	11.55	12.84	14.75
修正力场结果/10^-10m²·s^-1	0.41	0.64	1.15
阿伦尼乌斯方程拟合结果/10^-10m²·s^-1	0.41	0.61	0.89
实验结果/10^-10m²·s^-1	0.4	0.55	0.93

分子	原子	ϵ/kcal·mol^-1	σ/Å
反应物	N	0.325（修正值）	4.070
	H（—CH₂—、—NH₂）	0.013	1.098
	C	0.054	4.010
	O	1.200（修正值）	3.535
	H（—OH）	0.020	2.955
H₂O	H	0.013	1.098
H₂O	O	0.9864（修正值）	3.608
CO₂	C	0.064	4.010
CO₂	O	0.060	3.535
生成物	N	0.325（修正值）	3.262
	H	0.013	1.098
	C	0.120	3.908
	O（—NHCOO—中第一个O）	0.167	3.596
	O（—NHCOO—中第二个O）	1.200（修正值）	3.535

结果	303K	313K	323K
模拟值/10^-10m²·s^-1	4.76	5.81	7.12
实验值/10^-10m²·s^-1	4.49	5.76	7.27

英文缩写	中文名称	分子式	结构式	分子量
MEA	单乙醇胺	C₂H₇NO	NH₂CH₂CH₂OH	61.083
DEA	二乙醇胺	C₄H₁₁NO₂	NH(CH₂CH₂OH)₂	105.136
AEEA	羟乙基乙二胺	C₄H₁₂N₂O	NH₂CH₂CH₂NHCH₂CH₂OH	104.15
MDEA	甲基二乙醇胺	C₅H₁₃NO₂	CH₃N(CH₂CH₂OH)₂	119.16
EDEA	N-乙基二乙醇胺	C₆H₁₅NO₂	CH₃CH₂N(CH₂CH₂OH)₂	133.1888
DEA-1,2-PD	3-二乙氨基-1,2-丙二醇	C₇H₁₇NO₂	(CH₃CH₂)₂NCH₂(CHOH)CH₂OH	147.215

不同单胺溶剂	自扩散系数公式
MEA	$2.06 × 10 - 7 e - 13848 R T$
DEA	$5.31 × 10 - 7 e - 17772 R T$
MDEA	$4.6 × 10 - 7 e - 17367 R T$
AEEA	$1.5 × 10 - 7 e - 13850 R T$
EDEA	$2.83 × 10 - 7 e - 16046 R T$
DEA-1,2-PD	$2.53 × 10 - 7 e - 15750 R T$

不同单胺溶剂	自扩散系数公式
MEA	$2.06 × 10 - 7 e - 13848 R T$
DEA	$5.31 × 10 - 7 e - 17772 R T$
MDEA	$4.6 × 10 - 7 e - 17367 R T$
AEEA	$1.5 × 10 - 7 e - 13850 R T$
EDEA	$2.83 × 10 - 7 e - 16046 R T$
DEA-1,2-PD	$2.53 × 10 - 7 e - 15750 R T$

反应进度/%	分子个数
反应进度/%	MEA	DEA	MDEA	MEAH⁺MEACOO^-	DEAH⁺DEACOO^-	MDEAH⁺HCO $3 -$
0	253	147	130	0	0	0
10	227	133	117	13	7	13
20	203	117	104	25	15	26
30	177	103	91	38	22	39
40	151	89	78	51	29	52
50	127	73	65	63	37	65
60	101	59	52	76	44	78
70	77	45	39	88	51	91
80	51	29	26	101	59	104
90	25	15	13	114	66	117
100	0	0	0	126	74	130

反应进度/%	分子个数
反应进度/%	MEA	DEA	MDEA	MEAH⁺MEACOO^-	DEAH⁺DEACOO^-	MDEAH⁺HCO $3 -$
0	253	147	130	0	0	0
10	227	133	117	13	7	13
20	203	117	104	25	15	26
30	177	103	91	38	22	39
40	151	89	78	51	29	52
50	127	73	65	63	37	65
60	101	59	52	76	44	78
70	77	45	39	88	51	91
80	51	29	26	101	59	104
90	25	15	13	114	66	117
100	0	0	0	126	74	130

质量分数	分子个数
质量分数	MEA	DEA	MDEA	DEA-1,2-PD
0.06	50	29	26	21
0.08	67	39	35	28
0.10	84	49	43	35
0.12	101	59	52	42
0.14	118	69	60	49
0.16	135	78	69	56
0.18	152	88	78	63
0.20	169	98	86	70
0.22	185	108	95	77
0.24	202	117	104	84

References 30

[1]	D’ALESSANDRO Deanna M, SMIT Berend, LONG Jeffrey R. Carbon dioxide capture: Prospects for new materials[J]. Angewandte Chemie International Edition, 2010, 49(35): 6058-6082.
[2]	GAO Wanlin, LIANG Shuyu, WANG Rujie, et al. Industrial carbon dioxide capture and utilization: State of the art and future challenges[J]. Chemical Society Reviews, 2020, 49(23): 8584-8686.
[3]	ZHAO Xiaomeng, LI Xingyu, LU Houfang, et al. Predicting phase-splitting behaviors of an amine-organic solvent-water system for CO₂ absorption: A new model developed by density functional theory and statistical and experimental methods[J]. Chemical Engineering Journal, 2021, 422: 130389.
[4]	Mai BUI, ADJIMAN Claire S, BARDOW André, et al. Carbon capture and storage (CCS): The way forward[J]. Energy & Environmental Science, 2018, 11(5): 1062-1176.
[5]	HEPBURN Cameron, ADLEN Ella, BEDDINGTON John, et al. The technological and economic prospects for CO₂ utilization and removal[J]. Nature, 2019, 575(7781): 87-97.
[6]	MAKUL Natt. Towards computational CO₂ capture and storage models[J]. The Global Environmental Engineers, 2021, 8: 55-69.
[7]	ROCHELLE Gary T. Amine scrubbing for CO₂ capture[J]. Science, 2009, 325(5948): 1652-1654.
[8]	ZHANG Qi, BAHAMON Daniel, ALKHATIB Ismail I I, et al. Molecular insights into the CO₂ absorption mechanism by superbase protic ionic liquids by a combined density functional theory and molecular dynamics approach[J]. Journal of Molecular Liquids, 2024, 394: 123683.
[9]	DUTCHER Bryce, FAN Maohong, RUSSELL Armistead G. Amine-based CO₂ capture technology development from the beginning of 2013—A review[J]. ACS Applied Materials & Interfaces, 2015, 7(4): 2137-2148.
[10]	OSMAN Ahmed I, HEFNY Mahmoud, ABDEL MAKSOUD M I A, et al. Recent advances in carbon capture storage and utilisation technologies: A review[J]. Environmental Chemistry Letters, 2021, 19(2): 797-849.
[11]	SMIT Berend. Carbon capture and storage: Introductory lecture[J]. Faraday Discussions, 2016, 192: 9-25.
[12]	Alicia GARCÍA-ABUÍN, Diego GÓMEZ-DÍAZ, NAVAZA José M, et al. Carbon dioxide capture with tertiary amines. Absorption rate and reaction mechanism[J]. Journal of the Taiwan Institute of Chemical Engineers, 2017, 80: 356-362.
[13]	WANG M, LAWAL A, STEPHENSON P, et al. Post-combustion CO₂ capture with chemical absorption: A state-of-the-art review[J]. Chemical Engineering Research and Design, 2011, 89(9): 1609-1624.
[14]	YU Y S, LU H F, WANG G X, et al. Characterizing the transport properties of multiamine solutions for CO₂ capture by molecular dynamics simulation[J]. Journal of Chemical & Engineering Data, 2013, 58(6): 1429-1439.
[15]	CASTRO-ANAYA Luis E, OROZCO Gustavo A. Self-diffusion coefficients of amines, a molecular dynamics study[J]. Fluid Phase Equilibria, 2022, 553: 113301.
[16]	FENG Huajie, LIU Xin, GAO Wei, et al. Evolution of self-diffusion and local structure in some amines over a wide temperature range at high pressures: A molecular dynamics simulation study[J]. Physical Chemistry Chemical Physics, 2010, 12(45): 15007-15017.
[17]	SHARIF Maimoona, WU Xiaomei, YU Yunsong, et al. Estimation of diffusivity and intermolecular interaction strength of secondary and tertiary amine for CO₂ absorption process by molecular dynamic simulation[J]. Molecular Simulation, 2022, 48(6): 484-494.
[18]	MELNIKOV Sergey M, STEIN Matthias. The effect of CO₂ loading on alkanolamine absorbents in aqueous solutions[J]. Physical Chemistry Chemical Physics, 2019, 21(33): 18386-18392.
[19]	SNIJDER Erwin D, RIELE Marcel J M TE, VERSTEEG Geert F, et al. Diffusion coefficients of several aqueous alkanolamine solutions[J]. Journal of Chemical & Engineering Data, 1993, 38(3): 475-480.
[20]	BABA Hiromi, URANO Ryo, NAGAI Tetsuro, et al. Prediction of self-diffusion coefficients of chemically diverse pure liquids by all-atom molecular dynamics simulations[J]. Journal of Computational Chemistry, 2022, 43(28): 1892-1900.
[21]	HARUN N, MASIREN E E. Molecular dynamic simulation of amine-CO₂ absorption process[J]. Indian Journal of Science and Technology, 2017, 10(2): 110382.
[22]	LIN Po-Hsun, Chih-Chiang KO, LI Menghui. Ternary diffusion coefficients of diethanolamine and N-methyldiethanolamine in aqueous solutions containing diethanolamine and N-methyldiethanolamine[J]. Fluid Phase Equilibria, 2009, 276(1): 69-74.
[23]	KIM Sunkyung, SHI Hu, LEE Jin Yong. CO₂ absorption mechanism in amine solvents and enhancement of CO₂ capture capability in blended amine solvent[J]. International Journal of Greenhouse Gas Control, 2016, 45: 181-188.
[24]	YIANNOURAKOU M, UNGERER P, LEBLANC B, et al. Molecular simulation of adsorption in microporous materials[J]. Oil & Gas Science and Technology-Revue d’IFP Energies Nouvelles, 2013, 68(6): 977-994.
[25]	MOOSAVI Fatemeh, ABDOLLAHI Farkhondeh, RAZMKHAH Mohammad. Carbon dioxide in monoethanolamine: Interaction and its effect on structural and dynamic properties by molecular dynamics simulation[J]. International Journal of Greenhouse Gas Control, 2015, 37: 158-169.
[26]	RODNIKOVA M N, SAMIGULLIN F M, SOLONINA I A, et al. Molecular mobility and the structure of polar liquids[J]. Journal of Structural Chemistry, 2014, 55(2): 256-262.
[27]	Chih-Chiang KO, CHANG Wen-Haur, LI Menghui. Ternary diffusion coefficients of monoethanolamine and N-methyldiethanolamine in aqueous solutions[J]. Journal of the Chinese Institute of Chemical Engineers, 2008, 39(6): 645-651.
[28]	ORLOV Alexey Alam, VALTZ Alain, COQUELET Christophe, et al. Computational screening methodology identifies effective solvents for CO₂ capture[J]. Communications Chemistry, 2022, 5(1): 37.
[29]	ZHANG Shihan, SHEN Yao, SHAO Peijing, et al. Kinetics, thermodynamics, and mechanism of a novel biphasic solvent for CO₂ capture from flue gas[J]. Environmental Science & Technology, 2018, 52(6): 3660-3668.
[30]	CHOWDHURY Firoz A, YAMADA Hidetaka, HIGASHII Takayuki, et al. CO₂ capture by tertiary amine absorbents: A performance comparison study[J]. Industrial & Engineering Chemistry Research, 2013, 52(24): 8323-8331.