Industrial RB211 DLE Gas Turbine Combustion Update

2000 ◽  
Author(s):  
Jeffrey D. Willis ◽  
A. John Moran
Keyword(s):  
Gas Turbines ◽  
Combustion Process ◽  
Air Distribution ◽  
Fuel Quality ◽  
Ambient Conditions ◽  
Severe Damage ◽  
Pressure Oscillations ◽  
Lean Burn ◽  
Industrial Gas Turbines ◽  
Good Report

Industrial gas turbines have universally had problems with combustion amplified pressure oscillations (combustion instability or noise) in premix lean burn combustors. Reference 1 issued by General Electric is a particularly good report. Under specific conditions a resonant frequency achieves sufficient amplitude to cause severe damage to the combustor. As the emissions are reduced to lower levels, by achieving better uniformity of fuel and air distribution and a larger percentage of the air is used in the combustion process, then these amplitudes have the potential to become greater especially at high pressure ratios. Small changes in either ambient conditions or fuel quality appear to cause noise amplitudes to become unacceptable.

The Effect of Water Injection for Emissions Control on Industrial Gas Turbine Combustors

1984 ◽  
Author(s):  
R. J. Antos ◽  
W. C. Emmerling
Keyword(s):  
Gas Turbines ◽  
Mechanical Design ◽  
Water Injection ◽  
Combustion Process ◽  
Liquid Fuels ◽  
Nox Emissions ◽  
Design Features ◽  
Industrial Gas Turbines ◽  
Comprehensive Test ◽  
Industrial Gas Turbine

One common method of reducing the NOx emissions from industrial gas turbines is to inject water into the combustion process. The amount of water injected depends on the emissions rules that apply to a particular unit. Westinghouse W501B industrial gas turbines have been operated at water injection levels required to meet EPA NOx emissions regulations. They also have been operated at higher injection levels required to meet stricter California regulations. Operation at the lower rates of water did not affect combustor inspection and/or repair intervals. Operation on liquid fuels with high rates of water also did not result in premature distress. However, operation on gas fuel at high rates of water did cause premature distress in the combustors. To evaluate this phenomenon, a comprehensive test program was conducted; it demonstrated that the distress is the result of the temperature patterns in the combustor caused by the high rates of water. The test also indicated that there is no significant change in dynamic response levels in the combustor. This paper presents the test results, and the design features selected to substantially improve combustor wall temperature when operating on gas fuels, with the high rates of water injection required to meet California applications. Mechanical design features that improve combustor resistance to water injection-induced thermal gradients also are presented.

Numerical Assessment of SCAP: A Passive System for Preventing Thermoacoustic Oscillations in Gas Turbine Annular Combustors

2007 ◽  
Author(s):  
Stefano Tiribuzi
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Research Unit ◽  
Combined Cycle ◽  
Computational Time ◽  
Computational Domain ◽  
Ambient Conditions ◽  
Pressure Oscillations ◽  
Operation Conditions ◽  
Thermoacoustic Oscillations

ENEL operates a dozen combined cycle units whose V94.3A gas turbines are equipped with annular combustors. In such lean premixed gas turbines, particular operation conditions could trigger large pressure oscillations due to thermoacoustic instabilities. The ENEL Research unit is studying this phenomenon in order to find out methods which could avoid or mitigate such events. The use of effective numerical analysis techniques allowed us to investigate the realistic time evolution and behaviour of the acoustic fields associated with this phenomenon. KIEN, an in-house low diffusive URANS code capable of simulating 3D reactive flows, has been used in the Very Rough Grid approach. This approach permits the simulation, with a reasonable computational time, of quite long real transients with a computational domain extended over all the resonant volumes involved in the acoustic phenomenon. The V94.3A gas turbine model was set up with a full combustor 3D grid, going from the compressor outlet up to the turbine inlet, including both the annular plenum and the annular combustion chamber. The grid extends over the entire circular angle, including all the 24 premixed burners. Numerical runs were performed with the normal V94.3A combustor configuration, with input parameters set so as no oscillations develop in the standard ambient conditions. Wide pressure oscillations on the contrary are associated with the circumferential acoustic modes of the combustor, which have their onset and grow when winter ambient conditions are assumed. These results also confirmed that the sustaining mechanism is based on the equivalence ratio fluctuation of premix mixture and that plenum plays an important role in such mechanism. Based on these findings, a system for controlling the thermoacoustic oscillation has been conceived (Patent Pending), which acts on the plenum side of the combustor. This system, called SCAP (Segmentation of Combustor Annular Plenum), is based on the subdivision of the plenum annular volume by means of a few meridionally oriented walls. Repetition of KIEN runs with a SCAP configuration, in which a suitable number of segmentation walls were properly arranged in the annular plenum, demonstrated the effectiveness of this solution in preventing the development of wide thermoacoustic oscillations in the combustor.

scholarly journals Effects of Ambient Conditions and Fuel Composition on Combustion Stability

1997 ◽  
Author(s):  
Michael C. Janus ◽  
George A. Richards ◽  
M. Joseph Yip ◽  
Edward H. Robey
Keyword(s):  
Gas Turbines ◽  
Pressure Fluctuations ◽  
Field Testing ◽  
Combustion Stability ◽  
Fuel Composition ◽  
Ambient Conditions ◽  
Reaction Region ◽  
Industrial Gas Turbines ◽  
Thermal Nox ◽  
Combustion Oscillation

Recent regulations on NOx emissions are promoting the use of lean premix (LPM) combustion for industrial gas turbines. LPM combustors avoid locally stoichiometric combustion by premixing fuel and air upstream of the reaction region, thereby eliminating the high temperatures that produce thermal NOx. Unfortunately, this style of combustor is prone to combustion oscillation. Significant pressure fluctuations can occur when variations in heat release periodically couple to acoustic modes in the combustion chamber. These oscillations must be controlled because resulting vibration can shorten the life of engine hardware. Laboratory and engine field testing have shown that instability regimes can vary with environmental conditions. These observations prompted this study of the effects of ambient conditions and fuel composition on combustion stability. Tests are conducted on a subscale combustor burning natural gas, propane, and some hydrogen/hydrocarbon mixtures. A premix, swirl-stabilized fuel nozzle typical of industrial gas turbines is used. Experimental and numerical results describe how stability regions may shift as inlet air temperature, humidity, and fuel composition are altered. Results appear to indicate that shifting instability regimes are primarily caused by changes in reaction rate.

Advanced Catalytic Pilot for Low NOx Industrial Gas Turbines

2002 ◽  
Author(s):  
Hasan Karim ◽  
Kent Lyle ◽  
Shahrokh Etemad ◽  
Lance Smith ◽  
William Pfefferle ◽  
...  
Keyword(s):  
High Pressure ◽  
Surface Temperature ◽  
Gas Turbines ◽  
Lean Burn ◽  
Pressure Testing ◽  
Wide Range ◽  
Industrial Gas Turbines ◽  
Design And Testing ◽  
Pilot Burner ◽  
Load Conditions

This paper describes the design and testing of a catalytically-stabilized pilot burner for current and advanced Dry Low NOx (DLN) gas turbine combustors. In this paper, application of the catalytic pilot technology to industrial engines is described using Solar Turbines’ Taurus 70 engine. The objective of the work described is to develop the catalytic pilot technology and document the emission benefits of catalytic pilot technology when compared to higher, NOx producing pilots. The catalytic pilot was designed to replace the existing pilot in the existing DLN injector without major modification to the injector. During high pressure testing, the catalytic pilot showed no incidence of flashback or autoignition while operating over wide range of combustion temperatures. The catalytic reactor lit off at a temperature of approximately 598K (325°C/617°F) and operated at simulated 100% and 50% load conditions without a preburner. At high pressure, the maximum catalyst surface temperature was similar to that observed during atmospheric pressure testing and considerably lower than the surface temperature expected in lean-burn catalytic devices. In single injector rig testing, the integrated assembly of the catalytic pilot and Taurus 70 injector demonstrated NOx and CO emission less than 5 ppm @ 15% O2 for 100% and 50% load conditions along with low acoustics. The results demonstrate that a catalytic pilot burner replacing a diffusion flame or partially-premixed pilot in an otherwise DLN combustor can enable operation at conditions with substantially reduced NOx emissions.

Development and Application of Industrial Gas Turbines for Medium-Btu Gaseous Fuels

1986 ◽  
Vol 108 (1) ◽  
pp. 182-190 ◽  
Author(s):  
J. G. Meier ◽  
W. S. Y. Hung ◽  
V. M. Sood
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Combustion Process ◽  
Point Of View ◽  
Combustion System ◽  
Successful Development ◽  
Gaseous Fuels ◽  
Sanitary Landfills ◽  
Industrial Gas Turbines ◽  
Alternate Fuels

This paper describes the successful development and application of industrial gas turbines using medium-Btu gaseous fuels, including those derived from biodegradation of organic matters found in sanitary landfills and liquid sewage. The effects on the gas turbine and its combustion system of burning these alternate fuels compared to burning high-Btu fuels, along with the gas turbine development required to use alternate fuels from the point of view of combustion process, control system, gas turbine durability, maintainability and safety, are discussed.

Advanced Catalytic Pilot for Low NOx Industrial Gas Turbines

2003 ◽  
Vol 125 (4) ◽  
pp. 879-884 ◽  
Author(s):  
H. Karim ◽  
K. Lyle ◽  
S. Etemad ◽  
L. L. Smith ◽  
W. C. Pfefferle ◽  
...  
Keyword(s):  
High Pressure ◽  
Surface Temperature ◽  
Gas Turbines ◽  
Lean Burn ◽  
Pressure Testing ◽  
Wide Range ◽  
Industrial Gas Turbines ◽  
Design And Testing ◽  
Pilot Burner ◽  
Load Conditions

This paper describes the design and testing of a catalytically stabilized pilot burner for current and advanced Dry Low NOx (DLN) gas turbine combustors. In this paper, application of the catalytic pilot technology to industrial engines is described using Solar Turbines’ Taurus 70 engine. The objective of the work described is to develop the catalytic pilot technology and document the emission benefits of catalytic pilot technology when compared to higher, NOx producing pilots. The catalytic pilot was designed to replace the existing pilot in the existing DLN injector without major modification to the injector. During high-pressure testing, the catalytic pilot showed no incidence of flashback or autoignition while operating over wide range of combustion temperatures. The catalytic reactor lit off at a temperature of approximately 598 K (325°C/617°F) and operated at simulated 100% and 50% load conditions without a preburner. At high pressure, the maximum catalyst surface temperature was similar to that observed during atmospheric pressure testing and considerably lower than the surface temperature expected in lean-burn catalytic devices. In single-injector rig testing, the integrated assembly of the catalytic pilot and Taurus 70 injector demonstrated NOx and CO emission less than 5 ppm @ 15% O2 for 100% and 50% load conditions along with low acoustics. The results demonstrate that a catalytic pilot burner replacing a diffusion flame or partially premixed pilot in an otherwise DLN combustor can enable operation at conditions with substantially reduced NOx emissions.

Uncertainty Reduction in Gas Turbine Performance Diagnostics by Accounting for Humidity Effects

2001 ◽  
Author(s):  
K. Mathioudakis ◽  
A. Tsalavoutas
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Ambient Conditions ◽  
Ambient Temperatures ◽  
Turbine Performance ◽  
Industrial Gas Turbines ◽  
Industrial Gas Turbine ◽  
The Impact ◽  
Performance Diagnostics ◽  
Health Parameters

The paper presents an analysis of the effect of ambient humidity on the performance of industrial gas turbines and examines the impact of humidity on methods used for engine condition assessment and fault diagnostics. First, the way of incorporating the effect of humidity into a computer model of gas turbine performance is described. The model is then used to derive parameters indicative of the “health” of a gas turbine and thus diagnose the presence of deterioration or faults. The impact of humidity magnitude on the values of these health parameters is studied and the uncertainty introduced, if humidity is not taken into account, is assessed. It is shown that the magnitude of the effect of humidity depends on ambient conditions and is more severe for higher ambient temperatures. Data from an industrial gas turbine are presented to demonstrate these effects and to show that if humidity is appropriately taken into account, the uncertainty in the estimation of health parameters is reduced

Influence of Variations in the Natural Gas Properties on the Combustion Process in Terms of Emissions and Pulsations for a Heavy-Duty Gas Turbine

2003 ◽  
Author(s):  
Lars O. Nord ◽  
Helmer G. Andersen
Keyword(s):  
Natural Gas ◽  
Gas Turbine ◽  
Gas Turbines ◽  
Combustion Process ◽  
Mechanical Damage ◽  
Combustion Noise ◽  
Combustion Instabilities ◽  
Ambient Conditions ◽  
Process Data ◽  
Gas Properties

The natural gas supply can vary significantly on a day-to-day or even hour-to-hour basis for a power plant equipped with gas turbines. The influence of such variations could potentially have an adverse effect on the combustion process in terms of emissions and acoustic pulsations, even if the fuel properties are within the original equipment manufacturer (OEM) guidelines. Since the operation of a gas turbine typically requires steady emissions within the air permit as well as low pulsations to limit mechanical damage on the unit, fuel variations could significantly affect how the unit can be operated. To investigate this matter, data from an ALSTOM GT11N1 gas turbine was collected and studied during a 6-month period. The data acquired included on-line gas chromatograph readings, frequency-analyzed combustion instabilities, various process data, as well as ambient conditions. The collected data shows the magnitude of the changes in the emissions and combustion noise with changes in the fuel. The conclusion is that normal day-to-day variations in the natural gas properties do not have a significant effect on the emissions and combustion instabilities; however, larger sudden changes, as exemplified in the paper, could lead to considerable changes in the combustion behavior of the unit.

CFD Analysis of a Complete Industrial Lean Premixed Gas Turbine Combustor

2000 ◽  
Author(s):  
P. Birkby ◽  
R. S. Cant ◽  
W. N. Dawes ◽  
A. A. J. Demargne ◽  
P. C. Dhanasekaran ◽  
...  
Keyword(s):  
Gas Turbines ◽  
Combustion Process ◽  
Operating Conditions ◽  
Combustion Model ◽  
Reacting Flow ◽  
Lean Premixed Combustion ◽  
Fuel Injectors ◽  
Lean Premixed ◽  
Industrial Gas Turbines ◽  
Combustion Technology

The introduction of lean premixed combustion technology in industrial gas turbines has led to a number of interesting technical issues. Lean premixed combustors are especially prone to acoustically-coupled combustion oscillations as well as to other problems of flame stability such as flashback. Clearly it is very important to understand the physics that lies behind such behaviour in order to produce robust and comprehensive remedies, and also to underpin the future development of new combustor designs. Simulation of the flow and combustion using Computational Fluid Dynamics (CFD) offers an attractive way forward, provided that the modelling of turbulence and combustion is adequate and that the technique is applicable to real industrial combustor geometries. The paper presents a series of CFD simulations of the Rolls-Royce Trent industrial combustor carried out using the McNEWT unstructured code. The entire combustion chamber geometry is represented including the premixing ducts, the fuel injectors and the discharge nozzle. A modified k-ε model has been used together with an advanced laminar flamelet combustion model that is sensitive to variations in fuel-air mixture stoichiometry. Detailed results have been obtained for the non-reacting flow field, for the mixing of fuel and air and for the combustion process itself at a number of different operating conditions. The study has provided a great deal of useful information on the operation of the combustor and has demonstrated the value of CFD-based combustion analysis in an industrial context.

scholarly journals Transient Behavior in Variable Geometry Industrial Gas Turbines: A Comprehensive Overview of Pertinent Modeling Techniques

Entropy ◽  
2021 ◽  
Vol 23 (2) ◽  
pp. 250
Author(s):  
Muhammad Baqir Hashmi ◽  
Tamiru Alemu Lemma ◽  
Shazaib Ahsan ◽  
Saidur Rahman
Keyword(s):  
Steady State ◽  
Gas Turbine ◽  
Gas Turbines ◽  
Low Cycle Fatigue ◽  
Transient Behavior ◽  
Variable Geometry ◽  
Ambient Conditions ◽  
Comprehensive Overview ◽  
Modeling Techniques ◽  
Industrial Gas Turbines

Generally, industrial gas turbines (IGT) face transient behavior during start-up, load change, shutdown and variations in ambient conditions. These transient conditions shift engine thermal equilibrium from one steady state to another steady state. In turn, various aero-thermal and mechanical stresses are developed that are adverse for engine’s reliability, availability, and overall health. The transient behavior needs to be accurately predicted since it is highly related to low cycle fatigue and early failures, especially in the hot regions of the gas turbine. In the present paper, several critical aspects related to transient behavior and its modeling are reviewed and studied from the point of view of identifying potential research gaps within the context of fault detection and diagnostics (FDD) under dynamic conditions. Among the considered topics are, (i) general transient regimes and pertinent model formulation techniques, (ii) control mechanism for part-load operation, (iii) developing a database of variable geometry inlet guide vanes (VIGVs) and variable bleed valves (VBVs) schedules along with selection framework, and (iv) data compilation of shaft’s polar moment of inertia for different types of engine’s configurations. This comprehensive literature document, considering all the aspects of transient behavior and its associated modeling techniques will serve as an anchor point for the future researchers, gas turbine operators and design engineers for effective prognostics, FDD and predictive condition monitoring for variable geometry IGT.

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