Estimation of diffusivity and intermolecular interaction strength of secondary and tertiary amine for CO₂ absorption process by molecular dynamic simulation

ABSTRACT

CO₂ capture by absorption method is a promising way to realise CO₂ reduction in the industrial process. To reduce the cost of the CO₂ absorption and desorption process, people are looking for efficient solvents. Mixed solvents are an attractive way to solve the problem. Thus evaluating the mass transfer features of molecules is critical for mixed solvents in the CO₂ absorption process, which requires knowledge of the diffusion coefficient. 2-ethylamino ethanol (2EAE) and 2-dimethylamino ethanol (2DMAE) are selected for current study. The key objective of the current study is to investigate the diffusivity of 2EAE and 2DMAE and to explore the effect of the solvent concentration on the intermolecular interactions of selected amines. A molecular dynamic simulation analysis is carried out to assess the diffusivity and intermolecular interaction strength. Three different process temperatures were selected, i.e. 298, 313, and 318 K. The results show that as temperature rises, the rate of the diffusion coefficient increases. The CO₂ diffusivity on MEA is higher compared to 2DMAE but lower than that of 2EAE. The intermolecular interaction strength increases by increasing the solvent concentration. The highest intermolecular interactions in CO₂ are shown by 30%wt of 2EAE and 40%wt of 2DMAE.

KEYWORDS:

• CO₂ capture
• primary & secondary amine
• amine absorption process
• CO₂ diffusion coefficient
• molecular dynamic simulation

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

.This work was supported by China Postdoctoral Science Foundation: [grant number 2020M673390]; National Natural Science Foundation of China: [grant number Nos. 51876150 and 52106209].