Molecular Dynamics Simulations To Capture Nucleation and Growth of Particulates in Ethanolamine-Based Post-Combustion CO₂ Capture Columns

Abstract

Ethanolamines have traditionally been used for capturing CO 2 in a postcombustion carbon capture column. However, the use of ethanolamines, due to their high volatility and solvent losses, is not sustainable. One of the ways in which the solvent loss occurs is in the form of aerosols from the top of the column. The mechanism, rate of nucleation, growth rate, and interaction leading to the formation of aerosols, although essential for better process design, remain obscure. Using molecular dynamics simulations, we herein, analyze the formation of aerosols in columns based on aqueous monoethanolamine (MEA), aqueous methyldiethanolamine (MDEA), and their mixtures, using reference, pilot-scale, and industrial-scale data. In particular, the nucleation rate and cluster growth analyses were performed for five different cases. The results show that CO 2 concentration had a strong influence on the rate of aerosol formation, a factor that can be easily controlled for better process design. Moreover, the interactions within the formed aerosols were mainly dominated by CO 2 −water interactions. Taken together, our results and analysis contribute toward a better understanding of aerosol formation and present some practical value, namely, calculated nucleation rates and particulate growth rates can be used in process simulators to account for solvent losses, factors that were identified as contributing to formation of particulate matter can be controlled and adjusted in design process simulations and in real plants, providing better performance of postcombustion carbon capture columns and thus suggest ways to prevent solvent loss.

Insights into Aerosol Emission Control in the Postcombustion CO2 Capture Process: From Cluster Formation to Aerosol Growth

“…To explore potential enhancements in aerosol formation and growth, the gas temperature and vapor concentration in system B were adjusted. It is worth noting that noncondensable gases like N 2 /O 2 were excluded from the simulation, given their nonparticipation in the nucleation process. , Detailed information on molecule number and simulation box length (nm) under different simulation systems can be found in Table S1.…”

“…It is worth noting that noncondensable gases like N 2 /O 2 were excluded from the simulation, given their nonparticipation in the nucleation process. 36,37 Detailed information on molecule number and simulation box length (nm) under different simulation systems can be found in Table S1.…”

“…In contrast to gaseous components in aqueous absorption, those involved in particle formation and growth are supersaturated, leading to distinct mass transfer dynamics between the gas and liquid phases. Shah et al. , pioneered the exploration of the homogeneous nucleation of amine aerosols under supersaturated conditions via MD simulations. This approach sheds light on the overall nucleation rate and intermolecular interactions.…”

On Solvent Losses in Amine Absorption Columns

“…Recent studies estimated the nucleation rate of amine in PCCC plants using molecular dynamic (MD) simulation, which provides new insights into the nucleation process at the molecular levels. 34,35 However, implementation of the estimated nucleation rates using MD simulations in PCCC plants is lacking in the literature.…”

“…The simulation results mostly were not validated with experimental data, and none of them could predict the rate of nucleation and amine loss due to the nucleation process. Recent studies estimated the nucleation rate of amine in PCCC plants using molecular dynamic (MD) simulation, which provides new insights into the nucleation process at the molecular levels. , However, implementation of the estimated nucleation rates using MD simulations in PCCC plants is lacking in the literature.…”