Analysis of Compressor On-Line Washing to Optimize Gas Turbine Power Plant Performance

Author(s):  
Ernst Schneider ◽  
Saba Demircioglu Bussjaeger ◽  
Susana Franco ◽  
Dirk Therkorn

Due to compressor fouling, gas turbine efficiency decreases over time, resulting in decreased power output of the plant. To counteract the effects of compressor fouling, compressor on-line and off-line washing procedures are used. The effectiveness of compressor off-line washing is enhanced if combined with the cleaning of the VIGVs and the first compressor blade row by hand. This paper presents a thorough analysis of the effects of compressor on-line washing on the gas turbine performance. The analysis is based on the measured data of six gas turbines operated at two different plants. Different washing schedules and washing fluids are analyzed and compared. Furthermore, the effects of compressor on-line washing on the load distribution within the compressor are analyzed. The performance benefit of daily compressor on-line washing compared with weekly compressor on-line washing is quantified. As expected, daily compressor on-line washing yields the lowest power degradation caused by compressor fouling. Also, the effect of washing additives is analyzed. It is shown with long term data that compressor on-line washing cleans up to the first 11 compressor stages, as can be detected well in the compressor. With a view to gas turbine performance optimization, the recommendation is to perform compressor off-line washing at regular intervals and to take advantage of occasions such as inspections, when the gas turbine is cooled down anyhow. Especially for gas turbines with a high fouling rate, a daily compressor on-line washing schedule should be considered to reduce the power loss. For gas turbines operating with high fogging, compressor on-line washing has no added benefit. To determine the optimal compressor washing schedule, compressor blade erosion also has to be considered. A reasonable balance between compressor on-line washing and off-line washing improves the gas turbine performance and optimizes the gas turbine availability.

Author(s):  
Ernst Schneider ◽  
Saba Demircioglu ◽  
Susana Franco ◽  
Dirk Therkorn

Due to compressor fouling, gas turbine efficiency decreases over time, resulting in decreased power output of the plant. To counteract the effects of compressor fouling, compressor on-line and off-line washing procedures are used. The effectiveness of compressor off-line washing is enhanced if combined with the cleaning of the VIGVs and the first compressor blade row by hand. This paper presents a thorough analysis of the effects of compressor on-line washing on the gas turbine performance. The analysis is based on the measured data of six gas turbines operated at two different plants. Different washing schedules and washing fluids are analyzed and compared. Furthermore, the effects of compressor on-line washing on the load distribution within the compressor are analyzed. The performance benefit of daily compressor on-line washing compared to weekly compressor on-line washing is quantified. As expected, daily compressor on-line washing yields the lowest power degradation caused by compressor fouling. Also, the effect of washing additives is analyzed. It is shown with long term data that compressor on-line washing cleans up to the first 11 compressor stages, as can be detected well in the compressor. With a view to gas turbine performance optimization, the recommendation is to perform compressor off-line washing at regular intervals and to take advantage of occasions such as inspections, when the gas turbine is cooled down anyhow. Especially for gas turbines with a high fouling rate, a daily compressor on-line washing schedule should be considered to reduce the power loss. For gas turbines operating with high fogging, compressor on-line washing has no added benefit. To determine the optimal compressor washing schedule, compressor blade erosion also has to be considered. A reasonable balance between compressor on-line washing and off-line washing improves the gas turbine performance and optimizes the gas turbine availability.


2014 ◽  
Vol 136 (10) ◽  
Author(s):  
Uyioghosa Igie ◽  
Pericles Pilidis ◽  
Dimitrios Fouflias ◽  
Kenneth Ramsden ◽  
Panagiotis Laskaridis

Industrial gas turbines are susceptible to compressor fouling, which is the deposition and accretion of airborne particles or contaminants on the compressor blades. This paper demonstrates the blade aerodynamic effects of fouling through experimental compressor cascade tests and the accompanied engine performance degradation using turbomatch, an in-house gas turbine performance software. Similarly, on-line compressor washing is implemented taking into account typical operating conditions comparable with industry high pressure washing. The fouling study shows the changes in the individual stage maps of the compressor in this condition, the impact of degradation during part-load, influence of control variables, and the identification of key parameters to ascertain fouling levels. Applying demineralized water for 10 min, with a liquid-to-air ratio of 0.2%, the aerodynamic performance of the blade is shown to improve, however most of the cleaning effect occurred in the first 5 min. The most effectively washed part of the blade was the pressure side, in which most of the particles deposited during the accelerated fouling. The simulation of fouled and washed engine conditions indicates 30% recovery of the lost power due to washing.


Author(s):  
Jos Oosting ◽  
Klaas Boonstra ◽  
Annemarie de Haan ◽  
Dick van der Vecht ◽  
Jean-Pierre Stalder ◽  
...  

On line compressor washing is an established practice amid gas turbine operators. Among these operators is the Netherlands Division of Electrabel who is operating at Eemshaven 5 x GE Frame 9-FA units since 1995. The plant operator used to perform routinely a daily on line wash and a single off line wash every year at shut down of the units for the annual inspection or maintenance outage. The on line water wash (OLWW) systems installed on these 5 engines are of the Turbotect Mk1 nozzle design and were originally procured and supplied by the OEM. To our knowledge, all other manufactured gas turbines in the 7/9-FA fleet are equipped with the OEMs’ own engineered OLWW nozzle systems. The OLWW regime of washing was reduced in June 2001 upon receipt of a recommendation by the OEM to inspect the first stages of the compressor for erosion marks. This recommendation was issued because some events have lead to investigation on erosion issues which materialized in the R0 (first stage rotor) compressor blades in some engines of the 7/9-FA fleet operating with the OEM OLWW system and resulting from frequent compressor wash routine, and/or from water ingestion used in power augmentation. Likewise, during the same time, some gas turbines at Eemscentrale had undergone their first major overhaul which allowed the compressor first row blading to be examined for signs of erosion. It was found that only minor erosion at the R0 blade leading edge had occurred over more than seven years of operation, during which period a daily on line wash had been performed. However, because of the erosion concerns among the 7/9-FA fleet and the OEM-recommended frequent inspections and measures to mitigate the rate of erosion due to droplet impingement, Electrabel investigated independently for a way of further reducing the erosion rate while maintaining on line washing over the lifetime of the gas turbine and improving the cleaning efficiency. To this effect, the OLWW system on unit EC-6 was upgraded in June 2004 with a new on line nozzle system specifically developed for use in large gas turbines. This paper presents the investigation results after some 24 months of operation and routine on line compressor washing. The Turbotect Mk3 OLWW nozzle system demonstrated and confirmed that it is contributing to mitigate the erosion risk on the R0 compressor blade leading edge, and in turn to decrease the number of blending operations over the life time of the R0 compressor blades. This nozzle designed for on line compressor cleaning of large gas turbines achieved a substantially improved cleaning effectiveness, respectively a lower rate in power degradation, by approx. 30 to 40% as compared to the current in use Mk1 OLWW nozzle system.


2012 ◽  
Vol 452-453 ◽  
pp. 195-199 ◽  
Author(s):  
Lei Zhu ◽  
Hong Fu Zuo

Due to compressor fouling, gas turbine efficiency decreases over time, resulting in decreased power output of the plant. To counteract the effects of compressor fouling, compressor on-line and off-line washing procedures are used. The present research is aimed to propose a method of mathematical modeling of offline washing interval which will be estimated as the RUL of compressor based on Proportional hazards model. Application of the proposed prediction method to the case of Civil Aero-engine proved its effectiveness.


Author(s):  
George F. Gramatikas ◽  
Daniel L. Davis

This paper describes a program that groups gas turbines from one or more sites for the purpose of efficient monitoring and performance evaluation. Cost-improved gas turbine and power plant operation is achieved by a new, unified-yet-flexible service approach which combines state-of-the-art microprocessor-based monitoring with routine and emergency evaluation by a core of highly skilled personnel many miles from the operating site. This unique approach delivers expertise which supplements the gas turbine owner’s in-house resources. It is based on a modular concept of condition health monitoring and performance evaluation, including scheduled as well as on-line services. Portable condition health monitoring equipment provides the capability for scheduled plant performance evaluation by service engineers without investment in additional equipment. On-line monitoring includes a PC-based software system and a computer link to the service engineer’s headquarters. Both scheduled and on-line monitoring services include trend evaluation, projected maintenance requirements, maintenance planning assistance and suggestions for performance enhancement.


Author(s):  
Yongjun Zhao ◽  
Vitali Volovoi ◽  
Mark Waters ◽  
Dimitri Mavris

Traditionally the gas turbine power plant preventive maintenances are scheduled with constant maintenance intervals based on recommendations from the equipment suppliers. The preventive maintenances are based on fleet wide experiences, and they are scheduled in a one-size-fit-all fashion. However, in reality, the operating conditions for each gas turbine may vary from site to site, and from unit to unit. Furthermore, the gas turbine is a repairable deteriorating system, and preventive maintenance usually restores only part of its performance. This suggests the gas turbines need more frequent inspection and maintenance as it ages. A unit specific sequential preventive maintenance approach is therefore needed for gas turbine power plants preventive maintenance scheduling. Traditionally the optimization criteria for preventive maintenance scheduling is usually cost based. In the deregulated electric power market, a profit based optimization approach is expected to be more effective than the cost based approach. In such an approach, power plant performance, reliability, and the market dynamics are considered in a joint fashion. In this paper, a novel idea that economics drive maintenance expense and frequency to more frequent repairs and greater expense as the equipment and components age is introduced, and a profit based unit specific sequential preventive maintenance scheduling methodology is developed. To demonstrate the feasibility of the proposed approach, this methodology is implemented using a base load combined cycle power plant with single gas turbine unit.


Author(s):  
B. Chudnovsky ◽  
L. Levin ◽  
A. Talanker ◽  
V. Mankovsky ◽  
A. Kunin

Diagnostics of large size combined-cycle power plant components (such as: Gas Turbine, HRSG, Steam Turbine and Condenser) plays a significant role in improving power plant performance, availability, reliability and maintenance scheduling. In order to prevent various faults in cycle operation and as a result a reliability reduction, special monitoring and diagnostic techniques is required, for engineering analysis and utility production management. In this sense an on-line supervision system has developed and implemented for 370 MW combined-cycle. The advanced diagnostic methodology is based on a comparison between actual and target conditions. The actual conditions are calculated using data set acquired continuously from the power plant acquisition system. The target conditions are calculated either as a defined actual best operation (Manufacturer heat balances) or by means of a physical model that reproduces boiler and plant performance at off-design. Both sets of data are then compared to find the reason of performance deviation and then used to monitor plant degradation, to support plant maintenance and to assist on-line troubleshooting. The performance calculation module provides a complete Gas Turbine, HRSG and Steam Turbine island heat balance and operating parameters. This paper describes a study where an on-line performance monitoring tool was employed for continuously evaluating power plant performance. The methodology developed and summarized herein has been successfully applied to large size 360–370 MW combined cycles based on GE and Siemens Gas Turbines, showing good capabilities in estimating the degradation of the main equipment during plant lifetime. Consequently, it is a useful tool for power plant operation and maintenance.


Author(s):  
Steve Ingistov ◽  
Michael Milos ◽  
Rakesh K. Bhargava

A suitable inlet air filter system is required for a gas turbine, depending on installation site and its environmental conditions, to minimize contaminants entering the compressor section in order to maintain gas turbine performance. This paper describes evolution of inlet air filter systems utilized at the 420 MW Watson Cogeneration Plant consisting of four GE 7EA gas turbines since commissioning of the plant in November 1987. Changes to the inlet air filtration system became necessary due to system limitations, a desire to reduce operational and maintenance costs, and enhance overall plant performance. Based on approximately 2 years of operational data with the latest filtration system combined with other operational experiences of more than 25 years, it is shown that implementation of the high efficiency particulate air filter system provides reduced number of crank washes, gas turbine performance improvement and significant economic benefits compared to the traditional synthetic media type filters. Reasons for improved gas turbine performance and associated economic benefits, observed via actual operational data, with use of the latest filter system are discussed in this paper.


Author(s):  
Edgar Vicente Torres González ◽  
Raúl Lugo Leyte ◽  
Martín Salazar Pereyra ◽  
Helen Denise Lugo Méndez ◽  
Miguel Toledo Velázquez ◽  
...  

In this paper is carried out a comparison between a gas turbine power plant and a combined cycle power plant through exergetic and environmental indices in order to determine performance and sustainability aspects of a gas turbine and combined cycle plant. First of all, an exergetic analysis of the gas turbine and the combined is carried out then the exergetic and environmental indices are calculated for the gas turbine (case A) and the combined cycle (case B). The exergetic indices are exergetic efficiency, waste exergy ratio, exergy destruction factor, recoverable exergy ratio, environmental effect factor and exergetic sustainability. Besides, the environmental indices are global warming, smog formation and acid rain indices. In the case A, the two gas turbines generate 278.4 MW; whereas 415.19 MW of electricity power is generated by the combined cycle (case B). The results show that exergetic sustainability index for cases A and B are 0.02888 and 0.1058 respectively. The steam turbine cycle improves the overall efficiency, as well as, the reviewed exergetic indexes. Besides, the environmental indices of the gas turbines (case A) are lower than the combined cycle environmental indices (case B), since the combustion gases are only generated in the combustion chamber.


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