Degradation analysis of a combined cycle heat recovery steam generator under full and part load conditions

Abstract

In this paper, a theoretical model is proposed to simulate the performance and determine the degradation percentages of a Heat Recovery Steam Generator (HRSG) components at different operating loads and conditions. In addition, a new criterion is developed to determine the actual operational load of the HRSG based on the actual test performance (ATP) measured variables. The proposed model and the load determining criteria are applied to two-year collected data. After applying modeling procedure and load determining criteria, 10 readings were obtained for each operational month (January and August) every year for each operational loads of (100%, 75%, and 50%). The degradation analysis is carried out based on the actual power plant logged data; this distinguishes this research from the other studies in the same field. The results show that the degradation rate increases with time and with the operational load. On the other hand, there was no significant effect observed on the degradation rate by ambient conditions. Overall, the results indicate that the maximum degradation of the HRSG components was in the low-pressure stage of the HRSG at the full load and reached −6.73%, while the maximum overall degradation of the HRSG reached −6.02% at the full load.