Molecular Mechanism and Absorption Performance Evaluation of CO2 Capture from the PCC Process by Monoethanolamine-Based Deep Eutectic Solvents

Abstract

In the field of green chemistry, deep eutectic solvents (DESs) and their applications have always been a research hotspot. In this work, the absorption performance of CO₂ in DESs is studied by molecular dynamics(MD) simulation and process simulation. The microbehaviors of hydrogen bond acceptors (HBAs)/ hydrogen bond donors (HBDs) and DES/H₂O are studied by MD simulation. Through the analysis of interaction energy, radial distribution function, spatial distribution function, and diffusion coefficient the potential relationship between the absorption effect and molecular structure and aggregation characteristics is clarified. The key factors such as absorption mechanism and regeneration ability under various conditions are discussed. Because the high viscosity of DES hinders its commercial application, we studied the effects of temperature and water on the viscosity and absorption capacity of DES. After comprehensively considering the diffusion coefficient and the interaction energy, we recommend the use of 10% DES in industrial applications. In industrial applications, increasing system temperature has a more positive effect on ChCl/monoethanolamine (MEA) viscosity than adding water. The CO₂ removal process of MEA-based DESs is modeled and simulated using Aspen Plus. The feasibility and development trend of carbon dioxide capture is evaluated by sensitivity analysis. The CO₂ capture rate (RCO₂) is 99.03%, and the CO₂ purity in the product gas (PCO₂) is 99.06%. Global warming potential and eutrophication potential are considered. Compared with the traditional MEA process, this process has obvious advantages in product yield and environmental pollution. This work provides a technical reference for the realization of more efficient and environmentally friendly solvents in industrial applications. It will help industries such as coal and electricity to achieve low carbon emissions and promote sustainable development.