Performance analysis of absorber intercooling for a CO2 capture plant integrated with the natural gas combined cycle

An amine-based CO2 capture plant could mitigate CO2 emissions from a combined-cycle gas turbine (CCGT) plant, but it would require substantial energy. This investigation tackles this issue by assessing the merits of absorber intercooling (AIC) for a CO2 capture plant under the exhaust gas recirculation (50%EGR) and selective exhaust gas recirculation (70%SEGR) flue gas conditions for a CCGT plant, which, to the best of the authors' knowledge, has not been addressed in previous studies. The findings revealed that the greatest benefits of AIC were observed when the bulge temperature peaked at the center of the absorber under the critical lean loading. At the critical lean loading (mol CO2/mol MEA) of 0.35, 0.34, and 0.28 for baseline, EGR, and SEGR, respectively, installing three intercoolers in the absorber can reduce the bulge temperature by approximately 5–9 °C. This results in a 22–29% reduction in specific reboiler duty (SRD) across all configurations. In comparison, at the optimal lean loading of 0.20 across all configurations, the advantages of three intercoolers were limited to approximately 1–2 °C reductions in bulge temperature and around 7–9% reductions in SRD.