Temperature Control Scheme for Gas Turbine of Combined Cycles with Exhaust Gas Recirculation
Under partial-load conditions,the combined application of exhaust gas recirculation of heat recovery steam generator and compressor inlet guide vane adjustment(EGR-IGVC)can effectively improve the performance of gas turbine combined cycle.However,if this strategy is combined with the temperature control scheme of constant T3(turbine inlet temperature)-T4m(maximum allowable turbine exhaust temperature),which is often adopted in gas turbine combined cycles under part-load conditions,it would cause a large bottoming cycle exergy destruction and a significant decrease in bottoming cycle power output at relatively lower loads.In this paper,a constant T3-T4m-T4d(the design value of turbine exhaust temperature)scheme suitable for the EGR-IGVC strategy is proposed,the PG9351FA gas turbine combined cycle unit is taken as the research object,and the partial-load performance of combined cycle under the two temperature control schemes is compared and investigated based on energy and exergy analysis.The results show that the combination of the EGR-IGVC strategy with the constant T3-T4m scheme is still the best at the ambient temperature of 15 ℃ and the partial-load rate of above 80％.At a load of 30％-80％,compared with the constant T3-T4m scheme,the EGR-IGVC strategy combined with the constant T3-T4m-T4d scheme can increase the gas turbine efficiency by 0.15％-0.47％,and decrease the exergy destruction of the heat recovery steam generator by more than 0.51％(2.15 MW).The results also show that adopting the constant T3-T4m-T4d scheme can always obtain higher combined cycle efficiency when the ambient temperature varies between 0 and 40 ℃.In addition,the increase in partial-load efficiency becomes more evident with the rise of ambient temperature.
gas turbine combined cycleexhaust gas recirculation(EGR)compressor inlet guide vane(IGV)energy and exergy analysispartial load
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