Experimental verification and 4E analysis of a hydrate-based CO2 capture system for flue gas decarbonization

Gas hydrates, crystalline compounds composed of water and guest molecules, have gained attention for their potential in selective CO₂ capture and storage. This study evaluates hydrate-based CO₂ capture technologies for flue gas decarbonization through experimental investigations and process simulations. Hydrate formation and dissociation experiments examined two configurations: a two-stage high-pressure formation process using the kinetic promoter sodium p-styrenesulfonate, which achieved a 53.65% CO₂ removal rate and reduced concentration from 20 mol% to 9.27 mol%, and a three-stage low-pressure formation process employing both kinetic and thermodynamic promoters (TBAB and cyclopentane), attaining a 64.66% removal rate and lowering CO₂ concentration to 9.11 mol%. Complementary to the experimental data, process simulations was conducted by the Aspen HYSYS and Aspen EDR. Then the comprehensive 4E (Energy, Exergy, Economy, and Environment) analysis identified the Low-Pressure Formation with Atmospheric Dissociation (L-A) configuration as the most effective approach. The L-A process exhibited the lowest total energy consumption of 240,077 MJ/h and the highest exergy efficiency of 0.725. Economically, it presented significantly lower equipment and operational costs compared to high-pressure alternatives. Environmentally, the L-A configuration maintained indirect CO₂ emission ratios below one, indicating a net positive impact. These results suggest that the L-A process offers a balanced and efficient solution for industrial-scale CO₂ capture, combining technical feasibility, cost-effectiveness, and environmental sustainability.