Recoverable Versus Unrecoverable Degradations of Gas Turbines Employed in Five Natural Gas Compressor Stations

2015 ◽  
Vol 138 (2) ◽  
Author(s):  
K. K. Botros ◽  
C. Hartloper ◽  
H. Golshan ◽  
D. Rogers
Keyword(s):  
Gas Turbines ◽  
Measurement Errors ◽  
Standard Procedure ◽  
Engine Performance ◽  
Performance Degradation ◽  
Pipeline System ◽  
Variable Model ◽  
Air Compressor ◽  
Hourly Data ◽  
Over Time

Gas turbines (GT), like other prime movers, experience wear and tear over time, resulting in decreases in available power and efficiency. Further decreases in power and efficiency can result from erosion and fouling caused by the airborne impurities the engine breathes in. To counteract these decreases in power and efficiency, it is a standard procedure to “wash” the engine from time to time. In compressor stations on gas transmission systems, engine washes are performed off-line and are scheduled in such intervals to optimize the maintenance procedure. This optimization requires accurate prediction of the performance degradation of the engine over time. A previous paper demonstrated a methodology for evaluating various components of the GT gas path, in particular, the air compressor side of the engine since it is most prone to fouling and degradation. This methodology combines gas path analysis (GPA) to evaluate the thermodynamic parameters over the engine cycle followed by parameter estimation based on the Bayesian error-in-variable model (EVM) to filter the data of possible noise due to measurement errors. The methodology quantifies the engine-performance degradation over time, and indicates the effectiveness of each engine wash. In the present paper, the methodology was extended to assess both recoverable and unrecoverable degradations of five GT engines employed on TransCanada's pipeline system in Canada. These engines are: three GE LM2500+, one RR RB211-24G, and one GE LM1600 GTs. Hourly data were collected over the past 4 years, and engine health parameters were extracted to delineate the respective engine degradations. The impacts of engine loading, site air quality conditions, and site elevation on engine-air-compressor isentropic efficiency are compared between the five engines.

Assessment of Recoverable vs Unrecoverable Degradations of Gas Turbines Employed in Five Natural Gas Compressor Stations

2015 ◽  
Author(s):  
K. K. Botros ◽  
C. Hartloper ◽  
H. Golshan ◽  
D. Rogers
Keyword(s):  
Gas Turbines ◽  
Measurement Errors ◽  
Standard Procedure ◽  
Engine Performance ◽  
Performance Degradation ◽  
Pipeline System ◽  
Variable Model ◽  
Air Compressor ◽  
Hourly Data ◽  
Over Time

Gas Turbines (GT), like other prime movers, experience wear and tear over time, resulting in decreases in available power and efficiency. Further decreases in power and efficiency can result from erosion and fouling caused by the airborne impurities the engine breathes in. To counteract these decreases in power and efficiency, it is standard procedure to ‘wash’ the engine from time to time. In compressor stations on gas transmission systems, engine washes are performed off-line and are scheduled in such intervals to optimize the maintenance procedure. This optimization requires accurate prediction of the performance degradation of the engine over time. A previous paper demonstrated a methodology for evaluating various components of the GT gas path, in particular the air compressor side of the engine since it is most prone to fouling and degradation. This methodology combines Gas Path Analysis (GPA) to evaluate the thermodynamic parameters over the engine cycle followed by parameter estimation based on the Bayesian Error-in-Variable Model (EVM) to filter the data of possible noise due to measurement errors. The methodology quantifies the engine-performance degradation over time, and indicates the effectiveness of each engine wash. In the present paper, the methodology was extended to assess both recoverable and un-recoverable degradations of five gas turbine engines employed on TransCanada’s pipeline system in Canada. These engines are: three GE LM2500+, one RR RB211-24G, and one GE LM1600 gas turbines. Hourly data were collected over the past four years, and engine health parameters were extracted to delineate the respective engine degradations. The impacts of engine loading, site air quality conditions and site elevation on engine-air-compressor isentropic efficiency are compared between the five engines.

Effects of Engine Wash Frequency on GT Degradation in Natural Gas Compressor Stations

2013 ◽  
Author(s):  
K. K. Botros ◽  
H. Golshan ◽  
D. Rogers
Keyword(s):  
Gas Turbine ◽  
Standard Procedure ◽  
Engine Performance ◽  
Performance Degradation ◽  
Pipeline System ◽  
Variable Model ◽  
Turbine Engine ◽  
Wear And Tear ◽  
Optimal Maintenance ◽  
Over Time

Gas Turbine (GT), like other prime movers, undergoes wear and tear over time which results in performance drop as far as available power and efficiency is concerned. In addition to routine wear and tear, the engine also undergoes corrosion, fouling etc. due to the impurities it breathes in. It is standard procedure to ‘wash’ the engine from time to time to revive it. However, it is important to establish a correct schedule for the wash to ensure optimal maintenance procedure. This calls for accurate prediction of the performance degradation of the engine over time. In this paper, a methodology is presented to predict the performance degradation in a GE LM2500+ Gas Turbine engine used at one of TransCanada’s pipeline system, Canada. Evaluation of various components of the GT gas path, in particular the air compressor side of the engine since it is most prone to fouling and degradation is presented and correlated to the frequency and span of offline engine washes. Other components, such as the high pressure turbine and the power turbine are also evaluated. Although the results presented are for a specific engine type, the general framework of the model could be used for other engines as well to quantify degradation over time of other components within the GT engine. This model combines Gas Path Analysis (GPA) to evaluate the thermodynamic parameters over the engine cycle followed by parameter estimation based on Error-in-Variable Model (EVM) to filter the data of possible noise due to instrumentation errors. The model helps quantify the degradation in the engine performance over time and also indicates the effectiveness of each engine wash. The analysis will lead to better scheduling of the engine wash thereby optimizing operational costs as well as engine overhaul time.

Prediction of Gas Turbine Performance Degradation Between Soakwashes in Natural Gas Compressor Stations

2012 ◽  
Author(s):  
R. Chatterjee ◽  
K. K. Botros ◽  
H. Golshan ◽  
D. Rogers ◽  
Z. Samoylove
Keyword(s):  
Gas Turbine ◽  
Standard Procedure ◽  
Engine Performance ◽  
Performance Degradation ◽  
Pipeline System ◽  
Turbine Engine ◽  
Wear And Tear ◽  
Optimal Maintenance ◽  
Prime Movers ◽  
Over Time

Gas Turbine (GT), like other prime movers, undergoes wear and tear over time which results in performance drop as far as available power and efficiency is concerned. In addition to routine wear and tear, the engine also undergoes corrosion, fouling etc. due to the impurities it breathes in. It is standard procedure to ‘wash’ the engine from time to time to revive it. However, it is important to establish a correct schedule for the wash to ensure optimal maintenance procedure. This calls for accurate prediction of the performance degradation of the engine over time. In this paper, a methodology is presented to predict the performance degradation in a GE LM2500 Gas Turbine engine used at one of TransCanada’s pipeline system, Canada. Emphasis is laid on analyzing the degradation of the air compressor side of the engine since it is most prone to fouling and degradation. Although the results presented are for a specific engine type, the general framework of the model could be used for other engines as well to quantify degradation over time of other components within the GT engine. The present model combines Gas Path Analysis (GPA) to evaluate the thermodynamic parameters over the engine cycle followed by parameter estimation to filter the data of possible noise due to instrumentation errors. The model helps quantify the degradation in the engine performance over time and also indicates the effectiveness of each engine wash. The analysis will lead to better scheduling of the engine wash thereby optimizing operational costs as well as engine overhaul time.

Design, Development and Application of Vehicle Gas Turbine Engines

1966 ◽  
Vol 181 (1) ◽  
pp. 149-172
Author(s):  
P. A. Phillips ◽  
Peter Spear
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Low Cost ◽  
Engine Performance ◽  
Turbine Engines ◽  
Gas Turbine Engines ◽  
Design Development ◽  
Turbine Engine ◽  
Wide Range ◽  
Cycle Temperature

After briefly summarizing worldwide automotive gas turbine activity, the paper analyses the power plant requirements of a wide range of vehicle applications in order to formulate the design criteria for acceptable vehicle gas turbines. Ample data are available on the thermodynamic merits of various gas turbine cycles; however, the low cost of its piston engine competitor tends to eliminate all but the simplest cycles from vehicle gas turbine considerations. In order to improve the part load fuel economy, some complexity is inevitable, but this is limited to the addition of a glass ceramic regenerator in the 150 b.h.p. engine which is described in some detail. The alternative further complications necessary to achieve satisfactory vehicle response at various power/weight ratios are examined. Further improvement in engine performance will come by increasing the maximum cycle temperature. This can be achieved at lower cost by the extension of the use of ceramics. The paper is intended to stimulate the design application of the gas turbine engine.

Application of Forecasting Methodologies to Predict Gas Turbine Behavior Over Time

2011 ◽  
Author(s):  
A. Cavarzere ◽  
M. Venturini
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Current Trend ◽  
Performance Limit ◽  
Industrial Systems ◽  
Forecasting Method ◽  
Double Exponential ◽  
The Future ◽  
Double Exponential Smoothing ◽  
Over Time

The growing need to increase the competitiveness of industrial systems continuously requires a reduction of maintenance costs, without compromising safe plant operation. Therefore, forecasting the future behavior of a system allows planning maintenance actions and saving costs, because unexpected stops can be avoided. In this paper, four different methodologies are applied to predict gas turbine behavior over time: Linear and Non Linear Regression, One Parameter Double Exponential Smoothing, Baesyan Forecasting Method and Kalman Filter. The four methodologies are used to provide a prediction of the time when a performance limit will be exceeded in the future, as a function of the current trend of the considered parameter. The application considers different scenarios which may be representative of the trend over time of some significant parameters for gas turbines. Moreover, the Baesyan Forecasting Method, which allows the detection of discontinuities in time series, is also tested for predicting system behavior after two consecutive trends. The results presented in this paper aim to select the most suitable methodology that allows both trending and forecasting as a function of data trend over time, in order to predict time evolution of gas turbine characteristic parameters and to provide an estimate of the occurrence of a failure.

Rolls Royce/Allison 501-K Gas Turbine Anti-Fouling Compressor Coatings Evaluation

2002 ◽  
Author(s):  
Daniel E. Caguiat
Keyword(s):  
Gas Turbine ◽  
Fuel Consumption ◽  
Gas Turbines ◽  
Performance Degradation ◽  
Specific Fuel Consumption ◽  
Inlet Temperature ◽  
Test Results ◽  
Turbine Inlet ◽  
Compressor Performance ◽  
Compressor Efficiency

The Naval Surface Warfare Center, Carderock Division (NSWCCD) Gas Turbine Emerging Technologies Code 9334 was tasked by NSWCCD Shipboard Energy Office Code 859 to research and evaluate fouling resistant compressor coatings for Rolls Royce Allison 501-K Series gas turbines. The objective of these tests was to investigate the feasibility of reducing the rate of compressor fouling degradation and associated rate of specific fuel consumption (SFC) increase through the application of anti-fouling coatings. Code 9334 conducted a market investigation and selected coatings that best fit the test objective. The coatings selected were Sermalon for compressor stages 1 and 2 and Sermaflow S4000 for the remaining 12 compressor stages. Both coatings are manufactured by Sermatech International, are intended to substantially decrease blade surface roughness, have inert top layers, and contain an anti-corrosive aluminum-ceramic base coat. Sermalon contains a Polytetrafluoroethylene (PTFE) topcoat, a substance similar to Teflon, for added fouling resistance. Tests were conducted at the Philadelphia Land Based Engineering Site (LBES). Testing was first performed on the existing LBES 501-K17 gas turbine, which had a non-coated compressor. The compressor was then replaced by a coated compressor and the test was repeated. The test plan consisted of injecting a known amount of salt solution into the gas turbine inlet while gathering compressor performance degradation and fuel economy data for 0, 500, 1000, and 1250 KW generator load levels. This method facilitated a direct comparison of compressor degradation trends for the coated and non-coated compressors operating with the same turbine section, thereby reducing the number of variables involved. The collected data for turbine inlet, temperature, compressor efficiency, and fuel consumption were plotted as a percentage of the baseline conditions for each compressor. The results of each plot show a decrease in the rates of compressor degradation and SFC increase for the coated compressor compared to the non-coated compressor. Overall test results show that it is feasible to utilize anti-fouling compressor coatings to reduce the rate of specific fuel consumption increase associated with compressor performance degradation.

Some Effects of Size on the Performances of Small Gas Turbines

2003 ◽  
Author(s):  
C. Rodgers
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Engine Performance ◽  
Lessons Learned ◽  
Rapid Expansion ◽  
Cycle Performance ◽  
Frictional Drag ◽  
Component Design ◽  
Turbine Component ◽  
Performance Development

By the new millennia gas turbine technology standards the size of the first gas turbines of Von Ohain and Whittle would be considered small. Since those first pioneer achievements the sizes of gas turbines have diverged to unbelievable extremes. Large aircraft turbofans delivering the equivalent of 150 megawatts, and research micro engines designed for 20 watts. Microturbine generator sets rated from 2 to 200kW are penetrating the market to satisfy a rapid expansion use of electronic equipment. Tiny turbojets the size of a coca cola can are being flown in model aircraft applications. Shirt button sized gas turbines are now being researched intended to develop output powers below 0.5kW at rotational speeds in excess of 200 Krpm, where it is discussed that parasitic frictional drag and component heat transfer effects can significantly impact cycle performance. The demarcation zone between small and large gas turbines arbitrarily chosen in this treatise is rotational speeds of the order 100 Krpm, and above. This resurgence of impetus in the small gas turbine, beyond that witnessed some forty years ago for potential automobile applications, fostered this timely review of the small gas turbine, and a re-address of the question, what are the effects of size and clearances gaps on the performances of small gas turbines?. The possible resolution of this question lies in autopsy of the many small gas turbine component design constraints, aided by lessons learned in small engine performance development, which are the major topics of this paper.

A latent variable analysis of corporate social responsibility and firm value

2018 ◽  
Vol 44 (4) ◽  
pp. 478-494 ◽  
Author(s):  
Boonlert Jitmaneeroj
Keyword(s):  
Firm Value ◽  
Measurement Errors ◽  
Latent Variable ◽  
Fixed Effects ◽  
Latent Variable Model ◽  
Variable Model ◽  
Content Type ◽  
Latent Variable Analysis ◽  
Corporate Social ◽  
Variable Analysis

Purpose Corporate social responsibility (CSR) has several dimensions that are inherently unobservable or measured with errors. Due to measurement errors of CSR proxies, regression analysis seems inappropriate for investigating the relationship between CSR and firm value. Accounting for CSR measurement errors, the purpose of this paper is to use a latent variable analysis to examine whether CSR affects firm value. Design/methodology/approach This study applies a latent variable model that directly takes into account the measurement errors of CSR proxies. Moreover, the inclusion of firm-fixed effects in the model controls for time-invariant unobservable firm-specific characteristics that may drive both CSR and firm value. CSR is measured by environmental, social, and corporate governance activities. Findings Based on data of US firms between 2002 and 2014, this study finds conflicting evidence of a direct association between each CSR proxy and firm value. When all CSR proxies are incorporated into a latent variable model, CSR significantly positively impacts firm value. Therefore, CSR strategies based on a single measure of CSR or the equal weighting of CSR measures tend to underestimate the influence of CSR on firm value. Practical implications Corporate managers should enhance firm value by simultaneously engaging in environmental, social, and corporate governance activities because there is a synergistic effect with firm value. Furthermore, investors who downplay CSR factors in firm valuation can lead to significant errors in making equity investment choices. Originality/value This study presents a novel examination of the price-earnings ratio in the CSR valuation by using the latent variable model with firm-fixed effects.

Error Considerations for Turbine-Generator Torsional Vibration Monitoring

2020 ◽  
Author(s):  
Jindrich Liska ◽  
Jan Jakl ◽  
Sven Kunkel
Keyword(s):  
Power Systems ◽  
Torsional Vibration ◽  
Gas Turbines ◽  
Measurement Errors ◽  
Power Plants ◽  
Signal To Noise Ratio ◽  
Vibration Monitoring ◽  
Turbine Generator ◽  
Turbine Generators ◽  
Incremental Encoder

Abstract Turbine-generator torsional vibration is linked to electrical events in the power grid by the generator air-gap torque. Modern power systems are subject to gradual transformation by increasing flexibility demands and incorporation of renewable resources. As a result, electrical transient events are getting more frequent and thus torsional vibration is getting more and more attention. Especially in the case of large steam and gas turbines torsional vibration can cause material fatigue and present a hazard for safe machine operation. This paper freely builds on previous work, where a method for torsional vibration evaluation using an incremental encoder measurement was presented, in that it supplements error considerations to this methodology. Measurement errors such as precision of the rotor encoder manufacturing, choice of the proper sensor, its signal to noise ratio and the error of instantaneous velocity computation algorithm are analyzed. The knowledge of these errors is essential for torsional vibration as there is an indirect and relatively complicated path from the measurement to the final torsional vibration results compared to other kinds of vibration. The characteristics of particular errors of the processing chain are validated both on experimental data from a test rig as well as field data measured on turbine-generators in power plants.

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