Single-Atom Solvent for Enhanced CO2 Capture: Process Modeling and Multi-Objective Optimization

This work addresses the post-combustion CO2 capture demand, employing a single-atom solvent as the absorbent to conduct systematic research on process modeling, energy consumption analysis, and multi-objective optimization. The energy consumption of the single-atom solvent-enhanced CO2 capture process was reduced to 2.864 GJ/t, representing a 26.9% reduction compared with that of the conventional solution. The effects of solvent flow rate, gas flow rate, rich solvent temperature, reflux ratio, and extraction ratio on the energy consumption, annual total utility consumption, CO2 equivalent emissions, and total annual cost were systematically investigated. The results indicate that rich solvent temperature and reflux ratio are the most sensitive parameters affecting system energy consumption variations; increasing solvent flow rate linearly elevates the reboiler duty, whereas gas flow rate variations exert negligible influence on system performance. The energy consumption was further reduced to 1.84 GJ/t CO2 after process parameter optimization. A multi-objective optimization approach coupling the NSGA-II with Aspen Plus process simulation was developed for economic–energy–environmental optimization. Annual total utility consumption was reduced by 12.75%, CO2 equivalent emissions per unit of product were reduced by 47.87%, and total annual cost was reduced by 13.09% after optimization. The optimal operating conditions under multi-objective optimization were determined simultaneously. This study provides an optimization strategy for the industrial application of CO2 capture technology.