Degradation in Gas Turbine Systems

Abstract

Any prime mover exhibits the effects of wear and tear over time. The problem of predicting the effects of wear and tear on the performance of any engine is still a matter of discussion. Because the function of a gas turbine is the result of the fine-tuned cooperation of many different components, the emphasis of this paper is on the gas turbine and its driven equipment (compressor or pump) as a system, rather than on isolated components. We will discuss the effect of degradation on the package as part of a complex system (e.g., a pipeline, a reinjection station, etc.). Treating the gas turbine package as a system reveals the effects of degradation on the match of the components as well as on the match with the driven equipment. This article will contribute insights into the problem of gas turbine system degradation. Based on some detailed studies on the mechanisms that cause engine degradation, namely, changes in blade surfaces due to erosion or fouling, and the effect on the blade aerodynamics; changes in seal geometries and clearances, and the effect on parasitic flows; and changes in the combustion system (e.g., which result in different pattern factors), the effects of degradation will be discussed. The study includes a methodology to simulate the effects of engine and driven equipment degradation. With a relatively simple set of equations that describe the engine behavior, and a number of linear deviation factors which can easily be obtained from engine maps or test data, the equipment behavior for various degrees of degradation will be studied. A second model, using a stage by stage model for the engine compressor, is used to model the compressor deterioration. The authors have avoided to present figures about the speed of degradation, because it is subject to a variety of operational and design factors that typically cannot be controlled entirely.

Model Based Diagnosis and Supervision of Industrial Gas Turbines

“…In papers Diakunchak (1992); Kurz and Brun (2001); Kurz et al (2009), several mechanisms which cause degradation in gas turbines are presented. The major contribution of degradation mechanisms in an industrial gas turbine is fouling.…”

Simulation of a mixed-conducting membrane-based gas turbine power plant for CO2 capture: system level analysis of operation stability and individual process unit degradation

“…This phenomenon can lead to a decreased surge margin [22,23] and reduced efficiency as well as total flow rate of the compressor [15-18, 22, 24-26]. But fouling is usually recoverable to some extent [15,17,18,25,27]. The turbine efficiency decreases due to fouling or erosion [16,26].…”

“…The combustors in the conventional GTPP and the afterburners in the membrane-based GTPP are, in general, not directly affected by degradation [16,26,27,38]. Due to the lack of available data, degradation of the catalytic combustors in the membrane reactor [12] was also neglected.…”

A Model-Based Mixed Data Approach for Optimizing the Performance of an Offshore Gas Turbine Compressor

“…The correct construction and operation of the components of the gas turbine (GT) plant are also necessary for proper understanding and monitoring (Khalid et al 1998;Kurz and brun, 2001). Furthermore, the function of a GT is the result of the fine-tuned co-operation of the many different components of the plant.…”

“…Surge causes severe problems such as excessive pressure build-up at the inlet and cyclic loading on the compressor. These instabilities might lead to the inability of the compressor blade to produce the required compression and the engine might sustain catastrophic damage as a result of the excessive vibration (Iwakiri et al 2009 andKurz, 2009). The objective of this work is therefore to enunciate a method to further improve the operational performance of the GT through online water washing.…”