Keywords: evaporative gas turbines, part flow humidification, exergy analysis, optimisation, steam injection, exergy destruction, turbine inlet temperature, gas turbine cycles
Optimisation of the part-flow evaporative gas turbine cycles based on the exergy method
The evaporative gas turbine cycle is a new high-efficiency power cycle that has reached the pilot plant testing stage. The latest configuration proposed for this cycle is known as part flow evaporative gas turbine cycle (PEvGT) in which humidification is combined with steam injection. Having advantages of both steam injected and humid air cycles, it is regarded as a very desirable plant for future. In this paper, the exergy equations have been added to the mathematical model. Then exergy analysis and optimisation of the PEvGT cycles: PEvGT and PEvGT-IC (Intercooled PEvGT) have been done. This study shows the maximum exergy destruction rate related to combustion chamber in both cycles. The exergetic optimisation shows that the maximum second law efficiency occur in the highest values of part-flow humidification rate and turbine inlet temperature (β = 1, TIT = 1400°C).