INFLUENCE OF AMBIENT CONDITIONS ON AN AERODERIVATIVE GAS TURBINE BASED COGENERATION PLANT. A COMPARISON OF NUMERICAL SIMULATION WITH FIEL PERFORMANCE DATA

Gas turbine performances are directly related to outside conditions. The use of gas turbines in combined gas-steam power plants, also applied to cogeneration, increases performance dependence by outside conditions, because plants boundary conditions become more complex. In recent years, inlet air cooling systems have been introduced to control air temperature and humidity at compressor inlet resulting in an increase in plant power and efficiency. In this paper, the dependence of outside conditions for an existing cogenerative plant, located in Tuscany (Italy), is studied. The plant is equipped with two GE-LM6000 aeroderivative gas-turbines coupled with a three pressure level heat recovery steam generator, cogenerative application being related to the industrial district. The ambient temperature has been found to be the most important factor affecting the plant performance, but relative air humidity variation also has considerable effects. The field performance data are compared with a numerical simulation. The simulation results show a good agreement with the field performance data. The simulation allows evaluation of design and off-design plant performance and can become a useful tool to study the outside condition influence on power plant performance.