Thermally controlled absorber for enhanced point-source CO2 capture: Scaling up the process intensification packing technology

Abstract

This work describes a pilot-scale, thermally controlled gas–liquid absorption column designed for point-source carbon dioxide (CO₂) capture, featuring a 4-m tall, 0.3-m diameter absorber with a capacity of up to 1 t of CO₂ per day. Flue-gas conditions are simulated using a natural gas-fired power generation engine. A key advancement is the integration of a 3D-printed process intensification packing (PIP) device characterized by a double-wall structure that allows coolant flow through internal channels and gas–solvent counter-current flow on the exterior walls of the channels. This intrastage cooling mechanism is used to effectively manage the exothermic heat generated by the reaction of CO2 with the solvent to enhance CO2 capture. A 30 wt% aqueous monoethanolamine solvent, commonly used for point-source CO2 capture, and a gas stream containing 10–15% CO2 concentration were employed for the demonstration of the absorber. Experimental data confirmed a significant improvement in CO2 capture efficiency, increasing from 89% to 96% at simulated coal fired flue gas conditions and reaching up to 98%, with an average enhancement of ~5% for all experimental campaigns. Effective in-situ solvent cooling provided by the PIP device enabled a lower required liquid-to-gas (L/G) ratio and approximately 17% reduction in solvent flowrate requirements. Rate-based process simulations were performed to compare results with experimental data, while machine learning was employed using real-time data to validate and predict the effects of temperature control on absorber performance. The findings illustrate a promising pathway toward optimizing CO2 capture systems and achieving more sustainable industrial practices.