Readings on Specific Gas Turbine Flame Behaviours Using an Industrial Combustion Monitoring System

2016 ◽  
Author(s):  
Fabrice Giuliani ◽  
Hans Reiss ◽  
Markus Stuetz ◽  
Vanessa Moosbrugger ◽  
Alexander Silbergasser
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Dynamic Pressure ◽  
Pressure Sensors ◽  
Research Programme ◽  
Response Measurement ◽  
Efficient Operation ◽  
Maintenance Costs ◽  
Full Field ◽  
Combustion Monitoring

The new energy mix places greater demands on power gas turbine operation; precision combustion monitoring, therefore has become a major issue. Unforeseen events such as combustion instabilities can occur and represent a danger to the integrity of the hot parts and also lead to a limitation of the output power. This is usually accompanied by an increase in maintenance costs. The enlarged off-design operating envelope of gas turbines to adapt to a fast-changing grid has made this issue even more acute, necessitating an expansion of the operating envelope into areas that were — for many engines — not foreseen in the original combustor design process. A good understanding of what happens within the gas turbine combustor is crucial. Complex and costly full-field measurements such as laboratory optical instrumentation in precision combustion diagnostics are not suitable for permanent fleet deployment. For practical and financial reasons, the monitoring should ideally be achieved with a limited amount of discrete sensors. If installed and interpreted correctly, fast response measurement chains could lead to a better gas turbine combustion management, possibly yielding considerable savings in terms of operating and maintenance costs. The firm Meggitt Sensing System (MSS), assisted by Combustion Bay One (CBOne), initiated an applied research programme dedicated to this topic — with MSS providing the instrumentation and CBOne providing the facility and test conditions. The objective was to investigate realistic combustion phenomena in a precisely controlled and reproducible way and to document the individual readings of the heat-resistant fast pressure transducers mounted on the combustor casing, as well as the accelerometers mounted on the outer surface of the machine. Particular attention was paid to the correlation between these two types of sensor readings. This paper reports on the monitoring of the flame using piezoelectric dynamic pressure sensors and accelerometers in a number of different situations that are relevant to the safe and efficient operation of gas turbines. Discussed are single events such as flame ignition, lean blow-out and flash-back, as well as longer test sequences observing the effect of warming-up or the presence of flame instability. The measurement chains and processing techniques are discussed in detail. The atmospheric test rig used for this purpose and the different testing configurations required for each of these situations are also illustrated in detail. The results and recommendations for their implementation in an industrial context conclude this paper.

Durability Surveillance of Advanced Gas Turbines: Performance and Mechanical Baseline Development for the GE Frame 7F

1993 ◽  
Author(s):  
Cyrus B. Meher-Homji ◽  
A. N. Lakshminarasimha ◽  
G. Mani ◽  
Clark V. Dohner ◽  
Igor Ondryas ◽  
...  
Keyword(s):  
Electric Power ◽  
Gas Turbine ◽  
Gas Turbines ◽  
Dynamic Pressure ◽  
Pressure Sensors ◽  
Practical Interest ◽  
Advanced Technology ◽  
Surveillance Program ◽  
Inlet Temperature ◽  
Base Line

This paper describes the methodology and approach of baseline development as part of a comprehensive Durability Surveillance Study Program of an Advanced Gas Turbine (AGT) sponsored by the Electric Power Research Institute (EPRI) on a GE Frame 7F gas turbine operating in peaking service. The gas turbine is an advanced technology 156 MW (ISO), 955 lb/sec machine operating at a turbine inlet temperature of 2300° F (rotor inlet temperature) and a pressure ratio of 13.5:1. The turbine is located at Potomac Electric Power Company (PEPCO) Station H plant in Dickerson, Maryland. In order to facilitate the durability surveillance, the turbine has a data acquisition and analysis system which obtains data from the control system (via serial port) as well as from special sensors such as proximity probes, dynamic pressure sensors, strain gauges and hot section pyrometers. With the GE Frame 7F and FA machines becoming very popular in utility applications worldwide, the EPRI Durability Surveillance Program and baseline generation methodology will be of considerable practical interest to gas turbine users. The basic methodology presented for baseline development can be used for any single shaft gas turbine. We believe the base-line to be of considerable importance in evaluating future condition of the machine as well as for maintenance planning. The paper also briefly describes the status and future plans of the EPRI durability surveillance program.

Risk-Based Assessment of Unplanned Outage Events and Costs for Combined-Cycle-Plants

2012 ◽  
Author(s):  
Dale Grace ◽  
Thomas Christiansen
Keyword(s):  
Power Systems ◽  
Gas Turbine ◽  
Cash Flow ◽  
Gas Turbines ◽  
Operational Reliability ◽  
Combined Cycle ◽  
Maintenance Costs ◽  
Wide Range ◽  
Turbine Equipment ◽  
The Impact

Unexpected outages and maintenance costs reduce plant availability and can consume significant resources to restore the unit to service. Although companies may have the means to estimate cash flow requirements for scheduled maintenance and on-going operations, estimates for unplanned maintenance and its impact on revenue are more difficult to quantify, and a large fleet is needed for accurate assessment of its variability. This paper describes a study that surveyed 388 combined-cycle plants based on 164 D/E-class and 224 F-class gas turbines, for the time period of 1995 to 2009. Strategic Power Systems, Inc. (SPS®), manager of the Operational Reliability Analysis Program (ORAP®), identified the causes and durations of forced outages and unscheduled maintenance and established overall reliability and availability profiles for each class of plant in 3 five-year time periods. This study of over 3,000 unit-years of data from 50 Hz and 60 Hz combined-cycle plants provides insight into the types of events having the largest impact on unplanned outage time and cost, as well as the risks of lost revenue and unplanned maintenance costs which affect plant profitability. Outage events were assigned to one of three subsystems: the gas turbine equipment, heat recovery steam generator (HRSG) equipment, or steam turbine equipment, according to the Electric Power Research Institute’s Equipment Breakdown Structure (EBS). Costs to restore the unit to service for each main outage cause were estimated, as were net revenues lost due to unplanned outages. A statistical approach to estimated costs and lost revenues provides a risk-based means to quantify the impact of unplanned events on plant cash flow as a function of class of gas turbine, plant subsystem, and historical timeframe. This statistical estimate of the costs of unplanned outage events provides the risk-based assessment needed to define the range of probable costs of unplanned events. Results presented in this paper demonstrate that non-fuel operation and maintenance costs are increased by roughly 8% in a typical combined-cycle power plant due to unplanned maintenance events, but that a wide range of costs can occur in any single year.

Correlation Analysis of Multiple Sensors for Industrial Gas Turbine Compressor Blade Health Monitoring

2015 ◽  
Vol 137 (11) ◽  
Author(s):  
Brian Kestner ◽  
Tim Lieuwen ◽  
Chris Hill ◽  
Leonard Angello ◽  
Josh Barron ◽  
...  
Keyword(s):  
Gas Turbine ◽  
Acoustic Pressure ◽  
Dynamic Pressure ◽  
Pressure Sensors ◽  
Rotating Stall ◽  
Compressor Blade ◽  
Blade Vibration ◽  
Multiple Sensors ◽  
Dynamic Pressure Measurements ◽  
Industrial Gas Turbine

This paper summarizes an analysis of data obtained from an instrumented compressor of an operational, heavy duty industrial gas turbine; the goal of the aforementioned analysis is to understand some of the fundamental drivers, which may lead to compressor blade vibration. Methodologies are needed to (1) understand the fundamental drivers of compressor blade vibration, (2) quantify the severity of “events,” which accelerate the likelihood of failure and reduce the remaining life of the blade, and (3) proactively detect when these issues are occurring so that the operator can take corrective action. The motivation for this analysis lies in understanding the correlations between different sensors, which may be used to measure the fundamental drivers and blade vibrations. In this study, a variety of dynamic data was acquired from an operating engine, including acoustic pressure, bearing vibration, tip timing, and traditional gas path measurements. The acoustic pressure sensors were installed on the first four compressor stages, while the tip timing was installed on the first stage only. These data show the presence of rotating stall instabilities in the front stages of the compressor, occurring during every startup and shutdown, and manifesting itself as increased amplitude oscillations in the dynamic pressure measurements, which are manifested in blade and bearing vibrations. The data that lead to these observations were acquired during several startup and shutdown events, and clearly show that the amplitude of these instabilities and the rpm at which they occur can vary substantially.

scholarly journals Design and Test of a New Axial Compressor for the Nuovo Pignone Heavy Duty Gas Turbines

1996 ◽  
Author(s):  
Erio Benvenuti
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Dynamic Pressure ◽  
Pressure Ratio ◽  
Axial Compressor ◽  
Leading Edge ◽  
Meridional Flow ◽  
Heavy Duty ◽  
Pressure Transducers ◽  
Easy Integration

This axial compressor design was primarily focused to increase the power rating of the current Nuovo Pignone PGT10 Heavy-Duty gas turbine by 10%. In addition, the new 11-stage design favourably compares with the existing 17-stage compressor in terms of simplicity and cost. By seating the flowpath and blade geometry, the new aerodynamic design can be applied to gas turbines with different power ratings as well. The reduction in the stage number was achieved primarily through the meridional flow-path redesign. The resulting higher blade peripheral speeds achieve larger stage pressure ratios without increasing the aerodynamic loadings. Wide chord blades keep the overall length unchanged thus assuring easy integration with other existing components. The compressor performance map was extensively checked over the speed range required for two-shaft gas turbines. The prototype unit was installed on a special PGT10 gas turbine setup, that permitted the control of pressure ratio independently from the turbine matching requirements. The flowpath instrumentation included strain-gages, dynamic pressure transducers and stator vane leading edge aerodynamic probes to determine individual stage characteristics. The general blading vibratory behavior was proved fully satisfactory. With minor adjustments to the variable stator settings the front stage aerodynamic matching was optimized and the design performance was achieved.

Static and Dynamic Pressure Measurements With Temperature Correction Using High Temperature Optical Pressure Sensors

2010 ◽  
Author(s):  
A. P. R. Harpin
Keyword(s):  
High Temperature ◽  
Gas Turbine ◽  
Dynamic Range ◽  
Dynamic Pressure ◽  
Measurement Techniques ◽  
Pressure Sensors ◽  
Real Life ◽  
Temperature Correction ◽  
Harsh Environments ◽  
Wide Range

We describe our range of high temperature (1100°C) pressure sensors capable of measuring both static pressures of several Bar as required by gas turbine and jet engines, and measuring dynamic pressure fluctuations with a total dynamic range of in excess of 100000. This is achieved by a combination of rugged sensor design and our proprietary optical interrogator. This allows operation in harsh environments, EMI immunity, and simultaneous interrogation of not only static and dynamic pressure, but also the temperature of the sensor. This allows the sensor to maintain high accuracy over a wide range of operating temperatures. To date sensors have not been able to offer operation temperatures this high whilst enabling accurate dynamic pressure readings at the locations required. Also the static pressure cannot be retrieved simultaneously in real time from the same sensor. Also the temperature coefficient of the sensor has to be taken into account by measuring the temperature the sensor is operating at. Oxsensis has addressed these issues and we will present results showing dynamic pressure and temperature and explain how we can measure the temperature of the sensor with our interrogation schemes. We will describe the form of the sensor and the test data confirming its suitability for harsh environments. We will also explain the optical interrogator performance and present simulated results. The interrogator may be realised by a slave cavity or preferably on an integrated optical platform. As these sensors are intended for hostile gas turbine and aerospace environments, we will also present data from real life engine trials that we have performed, and compare the data we obtained with existing measurement techniques. Tests on a combustor rig have tested the sensor up to 1000°C, demonstrating that using our sensors in an engine at these temperatures is a realistic prospect. We believe that the ruggedness and performance of these sensors together with our complimentary interrogators mean that they are of significant interest to instrumentation of gas turbine engines and in the future the development of sophisticated engine feedback and emission control schemes, both in land based and aerospace environments.

Progress on Combined Optic-Acoustic Monitoring of Combustion in a Gas Turbine

2020 ◽  
Author(s):  
Lukas Andracher ◽  
Fabrice Giuliani ◽  
Nina Paulitsch ◽  
Vanessa Moosbrugger
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Soot Formation ◽  
Data Interpretation ◽  
Ignition Process ◽  
Spectral Bands ◽  
Technical Requirements ◽  
Other Information ◽  
Light Components ◽  
Combustion Monitoring

Abstract The need for better combustion monitoring in gas turbines has become more acute with the latest technical requirements, standards, and policies in terms of safety, environment, efficiency, operation flexibility and operation costs. This paper reports on a concept for gas turbine combustion monitoring using multiple probes that combine optical and acoustical measurements. The motivation of the project is twofold. On the one side, one wants to exploit the radiative feature of the flame and transform it into a piece of reliable information about the combustion status. On the other side, this information can be useful in terms of data interpretation or data reconciliation with other information coming from further sensors such as temperature probes, fast pressure probes or accelerometers. For this purpose, a set of multiple Rayleigh Criterion Probes (RCPs) combining optical and acoustical sensors is used. Detailed information about the RCP can be found in paper GT2017-63626, [1]. The focus is put on the detection of the flame, on the monitoring of the ignition process, on the quality assessment of combustion based on its spectral contents (including soot formation) and on the detection of possible combustion instabilities. The novel test rig used for validation of this advanced combustion monitoring concept is introduced, and minimal instrumentation including three probes is recommended. The split in red, green and blue (RGB) light components and their further analysis allows mapping the different types of operation. Solutions are proposed to bring the optical interface as near as possible to the flame and make it operational and reliable despite prevailing heat. The paper closes with a description of the ongoing tests on a pressurized combustion facility, and a sketch for a 3-RCPs based compact combustion monitoring system. The advantages of selected chromatic spectral bands are discussed, as well as the remaining challenges towards a full demonstration.

The Efficiency of Closed-Cycle Gas Turbines Controlled by Different Methods and Programs

2020 ◽  
pp. 51-63
Author(s):  
V.D. Molyakov ◽  
B.A. Kunikeev ◽  
N.I. Troitskiy
Keyword(s):  
Gas Turbine ◽  
Heat Exchangers ◽  
Gas Turbines ◽  
Power Plants ◽  
Control Method ◽  
Low Pressure ◽  
Working Fluid ◽  
Closed Cycle ◽  
Efficient Operation ◽  
Pressure Compressor

Closed-cycle gas turbine units can be used as power plants for advanced nuclear power stations, spacecraft, ground, surface and underwater vehicles. The purpose and power capacity of closed gas turbine units (CGTU) determine their specific design schemes, taking into account efficient operation of the units both in the nominal (design) mode and in partial power modes. Control methods of both closed and open gas turbine units depend on the scheme and design of the installation but the former differ from the latter mainly in their ability to change gas pressure at the entrance to the low-pressure compressor. This pressure can be changed by controlling the mass circulating in the CGTU circuit, adding or releasing part of the working fluid from the closed system as well as by internal bypassing of the working fluid. At a constant circulating mass in the single-shaft CGTU, the temperature of the gas before the turbines and the shaft speed can be adjusted depending on the type of load. The rotational speed of the turbine shaft, blocked with the compressor, can be adjusted in specific ways, such as changing the cross sections of the flow of the impellers. At a constant mass of the working fluid, the pressure at the entrance to the low-pressure compressor varies depending on the control program. The efficiency of the CGTU in partial power modes depends on the installation scheme, control method and program. The most economical control method is changing the pressure in the circuit. Extraction of the working fluid into special receivers while maintaining the same temperature in all sections of the unit leads to a proportional decrease in the density of the working fluid in all sections and the preservation of gas-dynamic similarity in the nodes (compressors, turbines and pipelines). Specific heat flux rates, and therefore, temperatures change slightly in heat exchangers. As the density decreases, heat fluxes change, as the heat transfer coefficient decreases more slowly than the density of the working fluid. With a decrease in power, this leads to a slight increase in the degree of regeneration and cooling in the heat exchangers. The underestimation of these phenomena in the calculations can be compensated by the underestimation of the growth of losses in partial power modes.

Combustion Oscillation Monitoring Using Flame Ionization in a Turbulent Premixed Combustor

2006 ◽  
Vol 129 (2) ◽  
pp. 352-357 ◽  
Author(s):  
B. T. Chorpening ◽  
J. D. Thornton ◽  
E. D. Huckaby ◽  
K. J. Benson
Keyword(s):  
Standard Deviation ◽  
Gas Turbine ◽  
Gas Turbines ◽  
Dynamic Pressure ◽  
Pressure Oscillation ◽  
Chamber Pressure ◽  
Ion Distribution ◽  
Combustion Dynamics ◽  
Gas Turbine Combustors ◽  
Flame Ionization

To achieve very low NOx emission levels, lean-premixed gas turbine combustors have been commercially implemented that operate near the fuel-lean flame extinction limit. Near the lean limit, however, flashback, lean blow off, and combustion dynamics have appeared as problems during operation. To help address these operational problems, a combustion control and diagnostics sensor (CCADS) for gas turbine combustors is being developed. CCADS uses the electrical properties of the flame to detect key events and monitor critical operating parameters within the combustor. Previous development efforts have shown the capability of CCADS to monitor flashback and equivalence ratio. Recent work has focused on detecting and measuring combustion instabilities. A highly instrumented atmospheric combustor has been used to measure the pressure oscillations in the combustor, the OH emission, and the flame ion field at the premix injector outlet and along the walls of the combustor. This instrumentation allows examination of the downstream extent of the combustion field using both the OH emission and the corresponding electron and ion distribution near the walls of the combustor. In most cases, the strongest pressure oscillation dominates the frequency behavior of the OH emission and the flame ion signals. Using this highly instrumented combustor, tests were run over a matrix of equivalence ratios from 0.6 to 0.8, with an inlet reference velocity of 25m∕s(82ft∕s). The acoustics of the fuel system for the combustor were tuned using an active-passive technique with an adjustable quarter-wave resonator. Although several statistics were investigated for correlation with the dynamic pressure in the combustor, the best correlation was found with the standard deviation of the guard current. The data show a monotonic relationship between the standard deviation of the guard current (the current through the flame at the premix injector outlet) and the standard deviation of the chamber pressure. Therefore, the relationship between the standard deviation of the guard current and the standard deviation of the pressure is the most promising for monitoring the dynamic pressure of the combustor using the flame ionization signal. This addition to the capabilities of CCADS would allow for dynamic pressure monitoring on commercial gas turbines without a pressure transducer.

Visualisation of Diffuser Instabilities in a Wet Gas Compressor

2015 ◽  
Author(s):  
Veronica Ferrara ◽  
Lars E. Bakken
Keyword(s):  
Oil And Gas ◽  
New Technologies ◽  
Dynamic Pressure ◽  
Pressure Sensors ◽  
Petroleum Industry ◽  
Research Programme ◽  
Open Loop ◽  
Ongoing Research ◽  
Wet Gas ◽  
Response Dynamic

The continuous demand for oil and gas pushes the petroleum industry to develop new technologies in order to increase production and exploit existing fields. The wet gas process, based on direct compression of unprocessed well stream subsea is a powerful means to expand the extraction of crude oil and gas and reach remote regions. Consequently centrifugal compressors are key elements that need to be developed in this area. Since no commercial subsea compressors are available and the liquid phase inside the standard process has to be avoided, it is essential to fully understand the machine behaviour, particularly investigate the presence of a gas-liquid mixture. Because of liquid impact, the performance of compressors and consequently the margin of stability may have to be modified. Here, delayed instability inception should be identified. An ongoing research programme is conducted at the Norwegian University of Science and Technology (NTNU) concerning the influence of wet gas on performance and aerodynamic stability. An open loop wet gas test rig is designed and employed in an experimental campaign. The main goal of this study is the visualisation of flow in a vaneless diffuser by means of special windows in Plexiglas, in correspondence with the diffuser and volute. Most attention is focused on the behaviour that leads to unstable phenomena, like stall and surge, in order to expose wet effects. Interactions between the diffuser and volute will also be taken into account. Simultaneously, the analysis will be supported by measurements from high-response dynamic pressure sensors. A fast Fourier transform (FFT) examination will be realised, in order to identify characteristic frequencies of unsteady events.

scholarly journals Optimum Operation and Maintenance of Gas Turbines Offshore

1996 ◽  
Author(s):  
Lars E. Bakken ◽  
Roald Skorping
Keyword(s):  
Gas Turbine ◽  
Thermal Efficiency ◽  
Test Performance ◽  
Gas Turbines ◽  
Operational Experience ◽  
Substantial Impact ◽  
Maintenance Costs ◽  
Total Potential ◽  
Operation And Maintenance ◽  
Optimum Energy

At present, offshore gas turbines are operated encouraging high thermal efficiency and low power consumption. High thermal efficiency normally demands operation close to full load, which may increase the emission of specific components. The present emission tax on CO2 has a substantial impact on gas turbine operation and maintenance costs. At present, it is of great importance to include the influence of emission taxes by focusing on optimum energy operation and maintenance. The influence of gas turbine degradation on operating costs is high. Analysis based on operational experience and field test performance data show an extra cost due to deterioration up to NOK 4.5 million a year. To obtain optimum energy operation and maintenance for the gas turbine drivers on Sleipner A, analysis and developments are based on: • on-line condition monitoring, to detect machinery condition and component degradation • prediction routines, to forecast degradation “development” as a function of time • optimisation routines, to predict optimum intervention time based on operating and maintenance costs • sensitivity analysis, including site performance correction to actual operating condition The developed procedure has resulted in increased flexibility and availability, in addition to reduced operating and maintenance costs. Total potential savings are estimated up to NOK 2.5 mill. per gas turbine a year. The system forms an important tool in future operation of the 60 gas turbines in present service.

Sign in / Sign up

Export Citation Format

Share Document