Gas Path Diagnostics for a Once-Through Steam Generator

Abstract

The performance of a once-through steam generator (OTSG) is bound to degrade due to fouling during its operation. The fouling will result in the degradation of the heat transfer between hot gas and water or steam on both sides of the tubes within the OTSG, thereby causing degraded OTSG performance. Such degradation could result in significant economic losses for a power plant where the OTSG plays a key role. Thus, it would be beneficial to develop a diagnostic method to quantify the fouling in an OTSG in order to support the condition monitoring and condition-based maintenance of the plant. In this study, a novel gas path diagnostic method for an OTSG based on Newton-Raphson method was developed to predict the OTSG degradation caused by fouling. The diagnostic method was applied to a model OTSG to test its effectiveness. The impact of measurement noise on the diagnostic accuracy was analyzed and discussed. A comparison between predicted and implanted degradation of a model OTSG demonstrated that the results are promising, and the method is satisfactory. Meanwhile, the diagnostic analysis of an OTSG based on real measurements has further proved that the developed diagnostic method works well and has a great potential to provide useful health information of OTSGs. In theory, the developed diagnostic method has the potential to be applied to different types of OTSGs.

A sequential model-based approach for gas turbine performance diagnostics

“…To analyze the influence of noise on diagnostic accuracy, measurement noise generated via the engine 446 thermodynamic model is imposed on the measured values. We have assumed that the noise is subject to a Gaussian 447 distribution with zero mean and standard deviation one, and the maximum deviation is shown in Table 10 [49,50]. We 448 assume that the engine measurements are recorded every 15 seconds, and for 5 minutes of steady-state operation, this 449 means that there are 20 operating points available.…”

Techno-economic evaluation and optimization of CCGT power Plant: A multi-criteria decision support system

“…The CCGT performance, including the GT, OTSG, and ST thermodynamic models is introduced first. The thermodynamic models previously developed by the authors and published in [38][39][40][41][42][43][44][45][46][47] are used in this study.…”

“…The parallel dual pressure OTSG performance model has been enhanced to include a fouling factor to facilitate the simulation of a degradation scenario, and validated using the MU power plant measurements [44]. Gas path analysis is used for the OTSGs in order to quantify the severity of tube fouling [45].…”