Thermodynamic performance analysis of retrofitted simple cycle gas turbine power plant

Abstract

The combined cycle power plant (CCPP) utilizes both gas and steam turbines to generate more than 50% electricity using the same fuel than the conventional simple cycle gas turbine power plant. The waste heat from the gas turbine is harnessed by the steam turbine utilizing the heat recovery steam generator (HRSG) to generate additional electricity, increase efficiency and reducing emission. Thermodynamic performance analysis of a retrofitted simple cycle gas turbine power plant was carried out. The studied gas turbine unit is the Siemens SGT5-2000E (3 units) gas turbine model with an installed capacity of 145 MW each located at the Geregu gas turbine power plant in Ajaokuta Kogi State. A one-year data covering March, 2018 to February, 2019 was used for the study in other to investigate the effect of ambient temperature on the performance parameters such as compressor work, turbine work, pump work, steam turbine work, power output and efficiency of the combined cycle power plant. The different control volumes of gas and steam turbines were subjected to thermodynamic study, and comparisons between simple and combined cycles were made. The analysis's predicted findings indicate that a drop in ambient temperature will boost power output, improve efficiency, and reduce emissions. Similar to this, a combined cycle power plant would produce more electricity and have a higher efficiency than a simple cycle gas turbine power plant.