Exploration of turbine blade cooling strategies for performance boosting and CO2 emissions reduction of combined cycle with steam injection based gas turbine

Abstract

The present work investigates the use of cooling schemes for the STeam Injection based Gas turbine (STIG) blades i.e. Steam Internal Convection Cooling (SICC) and Steam Transpiration Cooling (STC) techniques. The work aims to carry out the energy and exergy analyses considering variations in the design parameters like Gas Turbine Inlet Temperature (GTIT), Compressor Pressure Ratio (CPR), Turbine blade temperature (Tb ) and Steam mass Injection Ratio (SIR). The STIG Combined Cycle Power Plant (CCPP of 355 MW) performance and CO2 emissions are evaluated under the impact of these design parameters with these two cooling schemes, and comparison is made between them. The exergy efficiency increased by 2.98% points and CO2 emissions reduced by 0.0167 kg/kWh with STC scheme when compared with SICC scheme at GTIT = 1823 K, CPR = 12, Tb = 1123 K and SIR = 6 kg/kg of fuel. Exergy efficiency increased and CO2 emissions reduced with increase in SIR. Highlights Performance evaluation of STIG based CCPP with internal convection and transpiration cooling strategies using steam as a coolant applied to gas turbine blades. CO2 emissions reduction with high Steam mass injection ratio and with steam transpiration cooling scheme. The integration of STIG along with open loop steam cooling schemes enhances the performance of CCPP The exergy efficiency increases with increase in SIR, GTIT for STC scheme as compared to SICC scheme. STC is best cooling scheme with minimum coolant requirement.