Energy and Exergy Evaluation of a Dual Fuel Combined Cycle Power Plant: An Optimization Case Study of the Khoy Plant

Abstract

This study examines the energy and exergy performance of the Khoy dual fuel combined cycle power plant, focusing on dual pressure heat recovery steam generators (HRSGs). The aim is to identify an optimal design through the development of a thermodynamic model using ASPEN PLUS software. In the simulation, isentropic efficiencies of high-pressure and low-pressure steam turbines, gas turbines, and compressors are assumed to be 0.85, 0.80, 0.85, and 0.85, respectively. Various practical parameters, such as compressor pressure, condenser pressure, high-pressure steam turbine pressure, and outlet and inlet temperatures of superheaters and turbines, are investigated for their effects on energy and exergy efficiencies. The analysis reveals that combustion chamber I and combustion chamber II contribute the highest amounts of exergy destruction, accounting for 21.80% and 21.50% of the total exergy destruction, respectively. These areas are identified as requiring improvement. Based on the findings, an optimal design is presented, resulting in significant enhancements in energy and exergy efficiencies. The energy efficiency experiences a remarkable increase of 8.75%, while the exergy efficiency demonstrates a substantial improvement of 22.04%. This underscores the superiority of the optimized power plant configuration and provides valuable insights for designers, engineers, and power plant operators. In conclusion, this study advances the understanding of the energy and exergy performance of the Khoy dual fuel combined cycle power plant and offers guidance for optimizing its design and operation.