Aerosol formation in CO2 capture plants - molecular dynamics simulation
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Date
2017-12
Authors
Mansurov, Ulan
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Nazarbayev University School of Engineering and Digital Sciences
Abstract
Carbon dioxide capture is becoming a major concern not only from the perspective of traditional sour gas sweetening but also because of adverse effects of CO2 on climate change. The most conventional method to eliminate CO2 is carried out in a post-combustion CO2 capture (PCCC) column using aqueous monoethanolamine (MEA) as a solvent. Numerous reports have manifested significant amount of solvent losses due to formation of aerosols in PCCC columns. This research provides insights into formation mechanisms of aerosols or particulate matter (PM) at a molecular level by emphasizing interaction parameters between participating components. Molecular dynamics (MD) simulations were performed using GROMACS software. Five different systems under ordinary PCCC conditions were considered each of which has unique configuration of components. MD simulations revealed evolution and development of molecular clusters that formed PM which consisted of all gaseous MEA, SO2, major portion of CO2, and water vapor. Furthermore, quantitative analysis of the molecular clusters was carried out in terms of CO2 molecules. Nucleation rates of PM were in the order of 10-30 cm-3s-1. Also, formed aerosol particles were structurally examined using radial distribution functions (RDF) and determining pair potentials between the molecules. It was found that MEA in vapor phase contributes to PM formation. Furthermore, strong attraction potential between water and CO2 and MEA imply that the presence of water in vapor phase might be one of the key factors that forms and sustains PM. Taken together, the results are first of the efforts to understand PM (aerosol) formation in a typical PCCC column based on molecular simulations, and based on the findings of the study, certain practical suggestions were offered to avoid formation of PM.
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Mansurov, Ulan. 2017. Aerosol formation in CO2 capture plants - molecular dynamics simulation. Nazarbayev University School of Engineering