Modeling of heat recovery steam generator performance

Abstract

The performance of the heat recovery steam generator (HRSG) strongly affects the overall performance of a combined-cycle power plant. An accurate simulation of the performance of the HRSG is therefore necessary to analyze the effects of various design and operating parameters on the performance of combined-cycle power plants. Unfortunately, there are many sources of uncertainty and operational variance which prevent the accurate prediction of the HRSG performance. Furthermore, the prediction of heat-exchanger performance is based on assumptions about flow patterns. Empirical correction for departures from these assumptions is not possible in cases where the benefits of new geometrical configurations are to be explored. A numerical method was developed to predict the performance of the HRSG in a fashion that accounts, as much as possible, for the design and operation constraints, while keeping computational complexity manageable. The method is intended for use in performance-simulation models of advanced power cycles, since its accuracy is acceptable without requiring large computational resources. The method was used to simulate the pressure, temperature, steam quality and heat-flux distributions in a commercially available HRSG (operating under full- and part-load conditions). The predicted results were found to compare well with measurements obtained on full-scale units.