Effect of the Environmental Conditions of Tropical Climates on the Performance Parameters of a Gas Turbine Power Generation Plant

This paper studied the effects of atmospheric conditions on energy and exergy indicators of a two-axis General Electric LM5000 gas turbine power plant, an aerodynamically coupled power turbine and a Brush BDAX 7-290ER synchronous electric generator coupled and driven by the power turbine. The indicators studied were the mass air flow, the specific work consumed by the compressor, specific work produced by the turbine, the temperature of the flue gases, the NO concentration, the net output power, the thermal efficiency, the heat rate, specific fuel consumption, exergy destruction and exergy efficiency. A thermodynamic model was developed in EES, the thermodynamic model is validated with the gas turbine system parameters under ISO conditions, these parameters are the low pressure compressor outlet temperature, high pressure compressor outlet temperature, temperature of gas turbine output, net output power and thermal efficiency, which have a difference of less than 5%. The results showed that for each degree Celsius that the temperature of the air at the compressor inlet is reduced to constant relative humidity, on average the mass flow of dry air increases by 0.27 kg/s, the specific work consumed by the compressors decreases by 2.65 kJ / kg, the specific work delivered by the turbine is reduced by 0.84 kJ / kg, the temperature of the flue gas decreases by 0.44 ° C, the net output power is increased by 0.61%, the thermal efficiency is increased by 0.24%, the heat rate decreases by 25.24 kJ/kWh, the specific fuel consumption is reduced by 0.24%. exergy destruction increases by 101.15 kW and exergy efficiency increases by 0.24%. Likewise, it was observed that the NO concentration has its minimum values ​​when the air temperature is below 10 ° C. With respect to relative humidity, the results showed that increases in relative humidity at high temperatures cause greater changes in the evaluated indicators. An increase of 60 to 80% in relative humidity at 15 ° C decreases the output power by 82 kW, while for that same increment at 32 ° C the decrease in output power is 212 kW. The power plant studied is operating in Cartagena de Indias and since it is not operating in the design atmospheric conditions (15 ° C and 60% relative humidity), it experiences a loss of output power of 3537 kW and a drop in thermal efficiency of up to 6%. These results allow considering the implementation of air cooling technologies at the compressor inlet to compensate for the loss of power suffered by the atmospheric conditions of the installation site.