Abstract: Taking a 15 MW gas turbine and double-pressure heat recovery steam generator (HRSG) system as the object, the process of modeling and variable condition analysis by Thermoflow software was studied. The accuracy of the process simulation of the software was verified by the actual operation results of the plant, and the reliability of the software in engineering design was proved. The influencing factors of gas turbine and HRSG co-generation system were analyzed by using the software. The results showed that the gas turbine output decreased with the increase of ambient temperature, and the gas turbine output at 40℃ was 26.9% lower than that at -10℃. When the ambient temperature was lower than 15℃, the power generation efficiency of gas turbine increased with the increase of temperature. When the ambient temperature was higher than 15℃, the power generation efficiency of gas turbine decreased with the increase of temperature. The ambient relative humidity had little effect on the gas turbine system in general. With the increase of gas turbine load, the power generation efficiency of gas turbine was significantly increased, and the efficiency of gas turbine at 100% load was 5.7% higher than that at 50% load. The exhaust temperature of gas turbine decreased approximately linearly with the increase of gas turbine load, and when the load was raised to 87.5% and above, the exhaust temperature of gas turbine was stabilized at about 506°C. The HRSG exhaust temperature increased with the increase of gas turbine load, with a minimum of 149°C. When the gas turbine was operated at full load, the heat supply of co-generation system was 25,804 kW. The total thermal efficiency of co-generation system increased with the increase of gas turbine load, and the maximum total thermal efficiency of co-generation system was 87.07% when the gas turbine load reached 87.5%. The study results provided theoretical basis and data support for the optimized operation of the plant and the further energy saving and consumption reduction transformation.

Key words: gas turbine, HRSG, Thermoflow, system design