Abstract In this paper, we present the investigation towards the feasibility of turbine blade cooling using Exhaust Gas from the Exhaust Gas Recirculation (EGR) in Combined Cycle Gas Turbine (CCGT) power plants for enhanced carbon capture (CC). The study has been performed due to the need to develop more economical solutions for carbon capture in current CCGTs during the transition towards net zero. Based on theoretical studies, it is generally accepted that EGR should be applied in current CCGTs to reduce exhaust flow and increase its exhaust CO2 concentration. In this study, we explore an innovative approach that uses exhaust gas for cooling the turbine blade, referred to as exhaust gas cooling (EGC), as a potential solution for further increasing the CO2 concentration in the exhaust and reducing exhaust mass flow without impact on combustion. Results showed that, compared to conventional EGR, for the same O2 fraction at the combustor inlet, replacing compressor bleed air with exhaust gas for turbine cooling can increase the EGR ratio from 0.35 to 0.40 and reduce the exhaust mass flow by 91.2 kg/s (14.4%) in an H-class CCGT, leading to an increase in CO2 exhaust concentration by 15.32%. As a result, the size of the CC columns and their heat consumption were slightly reduced. With EGC, the power plant efficiency also increased by around 2%, mainly due to the use of exhaust gas with high specific heat for cooling.
Dubey et al. (Wed,) studied this question.