A model to predict the behaviour at part load operation of once-through heat recovery steam generators working with water at supercritical pressure

This paper describes a one-dimensional mathematical model that allows simulating the heat exchange in a steam generator working with water at supercritical pressure. The model has been developed in order to simulate the full and part load behaviour of heat recovery steam generators (HRSGs) of combined cycle gas turbine (CCGT) power plants. It takes into account the strong variation of some of the thermal and transport properties of fluids at supercritical pressure and discusses what parameters may be considered as constant along the heat exchanger. On the one hand, the model is useful because going supercritical is considered a way to further improve the efficiency of CCGT power plants and, on the other hand, because part load operation is the most usual operation mode in power plants.