Simulation of a combined cycle gas turbine power plant in Aspen HYSYS

A detailed model is developed in Aspen HYSYS for simulating the operation of a triple-pressure reheat combined cycle gas turbine (CCGT) power plant. To our knowledge, this is the first such model in the literature. A comparison with an equivalent GateCycle model shows that the predictions of the two models (Aspen HYSYS and GateCycle) are comparable. The average relative deviations for the power outputs and thermal efficiencies of the gas turbine, steam cycle, and CCGT plant are less than 2.0%. The minor discrepancies are primarily from the differences in gas enthalpy correlations. On the other hand, Aspen HYSYS may have some advantages over GateCycle. First, its use of the well-proven real-gas Peng-Robinson fluid package may give more accurate predictions. Second, it allows easy integration with various energy systems such as CO2 capture, organic Rankine cycles, fuel cells, LNG terminals, air separation, absorption chillers, etc. Third, its model can be made dynamic for predicting the real-time behaviour of a CCGT plant.