Power plant systems performance assessment with applications of combined pinch and exergy analysis

Abstract

Steam power plants forms an effective share of global electricity production. Thus, improving such plants performance is crucial to minimize its environmental effects and to enhance operational economy. Al-Mosyab thermal power station in Iraq is considered as a case study of this paper, with an objective of achieving best system performance. A combined pinch & exergy analysis (CPEA) is conducted under actual operating conditions. Further analytical attempt is varying pressure (165, 175, 185) bar, and temperature (450, 550, 620) °C at selected cycle location. Examining thereby the impact of each variable on the system power output, exergy destruction and 2nd low efficiency. The Engineering Equation Solving program (EES) is used for the simulation of each system components under these various operating conditions. The yielded results showed that the maximum mechanical & thermal output are (36.75 & 94.88) % of fuel energy respectively, while, turbine, boiler and condenser irreversibility and 2nd law efficiency are (157.76, 1086.18, 303.19) kJ/kg) and (88.36, 68.97, 28.68) % respectively. The analytical part of the analysis however showed that the high-pressure turbine network output increases by about (1%) with pressure variation, while such increase rise up to (70%) with temperature variation. Final concluded results predicted that best performance could be obtained at maximum pressure and temperature of (175) bar and (620) °C respectively.