Combined Cycle and Steam Gas-Fired Power Plant Analysis through Exergoeconomic and Extended Combined Pinch and Exergy Methods

Exergy analysis, thermoeconomics, and combined pinch and exergy analyses are useful methods for improving design and performance of processes such as thermal power plants. However, these methods are usually applied separately. In this paper, the methods are applied simultaneously to the 423-MW Neka combined-cycle power plant and the 315-MW Ramin steam power plant to evaluate and compare the performance of the systems and their components under different load conditions. To perform these analyses, a computer simulation and analysis program is developed. The simulator can predict the cycle behavior for different operating conditions with relative errors of less than 1.5%. The models are refined using performance test data from these plants. The system information is displayed graphically to visualize the performance of the systems for different conditions by applying combined pinch-exergy analysis. To better illustrate the plant performance and benefits of knowing the exergy destructions, the exergy destruction level (EDL) and the exergy cost destruction level (ECDL) are proposed and applied. Correspondingly, a new graphical representation is developed to illustrate the performance of each component based on exergoeconomic analysis, providing enhanced combined pinch-exergy and EDL/ECDL representations.