Exergy assessment of air film blade cooled combined power cycle plant

ABSTRACT

The present work aims at the comparative assessment of specific fuel consumption ($\text{SFC}$) and carbon dioxide ($\text{C}{\text{O}}_2$) emissions of combined power cycle plant ($\text{CPCP}$) with and without gas turbine blade cooling. The open loop air film cooling has been employed to cool the turbine blades. In this work, the irreversibility of components of $\text{CPCP}$ is estimated. The effect of gas turbine inlet temperature (GTIT) and compressor pressure ratio (CPR) on exergy efficiency and mass flow rate of the coolant are evaluated. The coolant flow requirement was 0.03579 kg/kg of gas. The exergy efficiency was decreased by 0.3%, SFC and $\text{C}{\text{O}}_2$ emissions were increased by 0.4% and 0.3% respectively (GTIT = 1473 K, CPR = 12) for cooled gas turbine based $\text{CPCP }$when compared with un-cooled one. Since the increment in $\text{SFC}$ and $\text{C}{\text{O}}_2$ emissions were marginal, it is recommended to use open loop air film cooling for $\text{CPCP}$ to ensure a longer life of blades.

KEYWORDS:

• Blade cooling
• combined cycle power plant
• heat recovery steam generator
• exergy efficiency
• irreversibility
• carbon dioxide emissions

Disclosure statement

No potential conflict of interest was reported by the authors.