Parametric Effects on Advanced Exergy and Exergoeconomics of a Gas-Fired Steam Power Plant Boiler

The achievable potentials for thermal system components improvement and the interactions of the system components cannot be obtained solely by the conventional exergy and exergoeconomic analysis. This information is imperative in the design and operation of installed thermal systems. However, advanced exergy and exergoeconomic analyses employ exergy destruction splitting to reveal the limitations associated with the conventional exergy analysis. Parametric advanced exergy analyses have been previously performed to assess the performances of some thermal systems, limited however to gas-fired steam turbine power plants. The goal of this study was to apply the advanced exergy and exergoeconomic analysis to the boiler of a gas-fired steam power plant to assess the performances of the superheater under different operating conditions (temperature and pressure). The operating temperature of the superheater were found to significantly affect the splits of exergy destruction and the sum of cost rates of avoidable endogenous exergy destruction and avoidable endogenous investment. Increasing the current plant operating temperature of the superheater decreases the avoidable, endogenous, avoidable endogenous and avoidable exogenous exergy destruction rates by 2.6% (1.4 MW), 4% (11.5 MW), 3% (1.2 MW) and 1.4% (0.2 MW), respectively. However, decreasing the current plant operating temperature of the superheater decreases the sum of cost rates of its avoidable endogenous exergy destruction and avoidable endogenous investment by 7% (350 $/h).