摘要
化学吸收法是当前广泛应用的CO_(2)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CO_(2)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CO_(2)捕集性能提供了重要的理论支持和模拟工具。
Chemical absorption is one of the most widely used CO_(2)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 CO_(2)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 CO_(2)capture performance of amine solvents.
作者
黄可儿
刘佳豪
李昊明
周天航
高金森
蓝兴英
HUANG Ke’er;LIU Jiahao;LI Haoming;ZHOU Tianhang;GAO Jinsen;LAN Xingying(State Key Laboratory of Heavy Oil Processing,China University of Petroleum(Beijing),Beijing 102249,China)
出处
《化工进展》
北大核心
2025年第8期4352-4364,共13页
Chemical Industry and Engineering Progress
基金
国家自然科学基金(U22B20149)。
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
CO_(2)capture
amine solvent
molecular dynamics
dynamic properties
mass transfer
molecular simulation
reaction progress
作者简介
第一作者:黄可儿(2000-),女,博士研究生,研究方向为人工智能及化学产品设计。E-mail:huangkeer0728@163.com;通信作者:周天航,博士,副教授,研究方向为人工智能及化学产品设计。E-mail:zhouth@cup.edu.cn;通信作者:蓝兴英,博士,教授,研究方向为人工智能及化学产品设计。E-mail:lanxy@cup.edu.cn。
