Evaluation of Inter-cooling in the Absorption Column for CO₂ Capture Using Diglycolamine Amine: Benefits and Economic Assessment

FISCHER, CARLOS D.; MUSSATI, MIGUEL C.; MOROSUK, TATIANA; MUSSATI, SERGIO F.

Memphis

Congreso; International Mechanical Engineering Congress & Exposition® Engineering Innovation for a Resilient Future; 2025

The ASME's International Mechanical Engineering Congress & Exposition (IMECE)

CO2 capture through chemical absorption with amines is a key technology for reducing emissions in industrial and energy sectors. Diglycolamine (DGA) stands out among the solvents employed due to its high absorption capacity and thermal stability. However, process performance largely depends on the efficiency of the absorption column, where the design of the cooling system plays a fundamental role.Inter-cooling or intermediate cooling within the absorption column has been proposed as a strategy to enhance CO2 capture efficiency. Decreasing the solution temperature at different stages of the column mitigates the reduction in absorption capacity associated with the temperature increase caused by the exothermic reaction. On the one hand, the decrease of the temperature helps maintain a higher CO2 concentration gradient up to chemical equilibrium, thereby increasing capture efficiency and/or reducing the required solvent flow rate. On the other hand, however, the implementation of inter-cooling entails additional costs associated with the installation of heat exchangers, extra energy and cooling water consumption, and specific design requirements – primarily dictated by the desired CO₂ capture level and composition –. Therefore, it is essential to carefully evaluate the economic feasibility of intercooling, considering not only the improvement in capture efficiency but also operational and investment costs in the overall process.This study presents a detailed analysis of the benefits of intercooling in the absorption column for CO2 capture using DGA, comparing different configurations and their impact on overall process efficiency. The trade-offs between the capture capacity, energy consumption, and implementation costs are evaluated, providing criteria for decision-making in the optimal design of CO2 capture systems with this type of solvent.