Hydrogen Combustion at High Combustor Airflow Using an Impinging Jet Flame Stabiliser With No Flashback and Low NOx

2012 ◽  
Author(s):  
Gordon E. Andrews ◽  
Mohamed A. Altaher ◽  
Hu Li
Keyword(s):  
Gas Turbines ◽  
Hydrogen Combustion ◽  
Inlet Temperature ◽  
Nox Emissions ◽  
Fuel Injector ◽  
Jet Flame ◽  
Air Jets ◽  
Industrial Gas Turbines ◽  
Stability Issue ◽  
Thermal Nox

The feasibility of hydrogen as a fuel for industrial gas turbines with low NOx emissions was investigated. Conventional well mixed flame stabilisers are difficult to use with 100% hydrogen owing to the flash back problem, which is potentially seven times worse for hydrogen due to its higher reactivity. This work was carried out using a rapidly mixed Jet Mix design, which had previously been investigated with NG and propane. This consisted of eight radial air jets into which the fuel was injected on their centrelines. These radial jets impinged into eight axial air jets which carried the bulk of the combustion air. Radial jet air flow proportions of 6.5% and 20% were investigated at an overall pressure loss at M1 = 0.047 of 4.3% in a 76mm diameter combustor. The reference Mach number, M1 of 0.047 represents all the compressor exit air entering the combustor with no dilution air. Very lean mixtures are required for low NOx emissions and there is no flame stability issue with hydrogen combustion, so all power turndown can be achieved with one main fuel injector. An inlet temperature of 600K was used at atmospheric pressure and the flames were lean enough to have temperatures where there was no pressure dependence of thermal NOx. For 6.5% radial air NOx emissions of 25ppm at 15% oxygen were demonstrated at 1800K and lower NOx at lower turbine entry temperatures.

scholarly journals Reduced NOx Emissions Using Low Radial Swirler Vane Angles

1991 ◽  
Author(s):  
H. S. Alkabie ◽  
G. E. Andrews
Keyword(s):  
Gas Turbines ◽  
Fuel Injection ◽  
Combustion Efficiency ◽  
Inlet Temperature ◽  
Nox Emissions ◽  
Primary Zone ◽  
Industrial Gas Turbines ◽  
Curved Blade ◽  
Swirl Vane ◽  
Vane Angle

The influence of vane angle and hence swirl number of a radial swirler on the weak extinction, combustion inefficiency and NOx emissions was investigated at lean gas turbine combustor primary zone conditions. A 140mm diameter atmospheric pressure low NOx combustor primary zone was developed with a Mach number simulation of 30% and 43% of the combustor air flow into the primary zone through a curved blade radial swirler. The range of radial swirler vane angles was 0–60 degrees and central radially outward fuel injection was used throughout with a 600K inlet temperature. For zero vane angle radially inward jets were formed that impinged and generated a strong outer recirculation. This was found to have much lower NOx characteristics compared with a 45 degree swirler at the same pressure loss. However, the lean stability and combustion efficiency in the near weak extinction region was not as good. With swirl the central recirculation zone enhanced the combustion efficiency. For all the swirl vane angles there was little difference in combustion inefficiency between the swirlers. However, the NOx emissions were reduced at the lowest swirl angles and vane angles in the range 20–30 degrees were considered to be the optimum for central injection. NOx emissions for central injection as low as 5ppm at 15% oxygen and 1 bar were demonstrated for zero swirl and 20 degree swirler vane angle. This would scale to well under 25 ppm at pressure for all current industrial gas turbines.

Reduced NOx Diffusion Flame Combustors for Industrial Gas Turbines

2000 ◽  
Vol 123 (4) ◽  
pp. 757-765 ◽  
Author(s):  
A. S. Feitelberg ◽  
V. E. Tangirala ◽  
R. A. Elliott ◽  
R. E. Pavri ◽  
R. B. Schiefer
Keyword(s):  
Diffusion Flame ◽  
Gas Turbines ◽  
Turbulent Flame ◽  
Steam Injection ◽  
Flame Length ◽  
Inlet Temperature ◽  
Nox Emissions ◽  
Complete Combustion ◽  
Industrial Gas Turbines ◽  
Fuel Nozzle

This paper describes reduced NOx diffusion flame combustors that have been developed for both simple cycle and regenerative cycle MS3002 and MS5002 gas turbines. Laboratory tests have shown that when firing with natural gas, without water or steam injection, NOx emissions from the new combustors are about 40 percent lower than NOx emissions from the standard combustors. CO emissions are virtually unchanged at base load, but increase at part load conditions. Commercial demonstration tests have confirmed the laboratory results. The standard combustors on both the MS3002 and MS5002 gas turbine are cylindrical cans, approximately 10.5 inches (27 cm) in diameter. A single fuel nozzle is centered at the inlet to each can and produces a swirl stabilized diffusion flame. The walls of the cans are louvered for cooling, and contain an array of mixing and dilution holes that provide the air needed to complete combustion and dilute the burned gas to the desired turbine inlet temperature. The MS3002 turbine is equipped with six combustor cans, while the MS5002 turbine is equipped with twelve combustors. The new, reduced NOx emissions combustors (referred to as a “lean head end,” or LHE, combustors) retain all of the key features of the conventional combustors; the only major difference is the arrangement of the mixing and dilution holes in the cylindrical combustor cans. By optimizing the number, diameter, and location of these holes, NOx emissions can be reduced considerably. Minor changes are also sometimes made to the combustor cap. The materials of construction, pressure drop, and fuel nozzle are all unchanged. The differences in NOx emissions between the standard and LHE combustors, as well as the variations in NOx emissions with firing temperature, are well correlated using turbulent flame length arguments. Details of this correlation are presented.

scholarly journals Ultra Low NOx Emissions for Gas and Liquid Fuels Using Radial Swirlers

1989 ◽  
Author(s):  
H. S. Alkabie ◽  
G. E. Andrews
Keyword(s):  
Gas Turbines ◽  
Fuel Injection ◽  
Air Flow ◽  
Combustion Efficiency ◽  
Liquid Fuels ◽  
Inlet Temperature ◽  
Flame Stability ◽  
Nox Emissions ◽  
Gas Oil ◽  
Industrial Gas Turbines

Curved blade radial swirlers using all the primary air were investigated with applications to lean burning gas turbine combustor primary zones with low NOx emissions. Two modes of fuel injection were compared, central and radial swirler pássage injection for gaseous and liquid fuels. Both fuel systems produced low NOx emissions but the upstream mixing in the swirler passages resulted in ultra low NOx emissions. A 140mm diameter atmospheric pressure combustor was used with 43% of the combustor air flow into the primary zone through the radial swirler. Radial gas composition measurements at various axial distances were made and these showed that the flame stability and NOx emissions were controlled by differences in local mixing at the base of the swirling shear layer downstream of the swirler outlet. For radial passage fuel injection it was found that a very high combustion efficiency was obtained for both propane and liquid fuels at 400K and 600K inlet temperatures. The flame stability, although worse than for central fuel injection was considerably better than for a premixed system. The NOx emissions at one bar pressure and 600K inlet temperature, compatible with a high combustion efficiency, for propane and kerosene were 3 and 6 ppm at 15% oxygen. For Gas Oil the NOx emissions were higher, but were still very low at 12ppm. Assuming a square root dependence of NOx on pressure these results indicate that NOx emissions of 48ppm for Gas Oil and less than 12ppm for gaseous fuels could be achieved at 16 bar pressure, which is typical of recent industrial gas turbines. High air flow radial swirlers with passage fuel injection have the potential for a dry solution to the NOx emissions regulations.

Reduced NOx Diffusion Flame Combustors for Industrial Gas Turbines

2000 ◽  
Author(s):  
Alan S. Feitelberg ◽  
Venkat E. Tangirala ◽  
Richard A. Elliott ◽  
Roointon E. Pavri ◽  
Richard B. Schiefer
Keyword(s):  
Diffusion Flame ◽  
Gas Turbines ◽  
Turbulent Flame ◽  
Steam Injection ◽  
Flame Length ◽  
Inlet Temperature ◽  
Nox Emissions ◽  
Complete Combustion ◽  
Industrial Gas Turbines ◽  
Fuel Nozzle

This paper describes reduced NOx, diffusion flame combustors that have been developed for both simple cycle and regenerative cycle MS3002 and MS5002 gas turbines. Laboratory tests have shown that when firing with natural gas, without water or steam injection, NOx emissions from the new combustors are about 40% lower than NOx emissions from the standard combustors. CO emissions are virtually unchanged at base load, but increase at part load conditions. Commercial demonstration tests have confirmed the laboratory results. The standard combustors on both the MS3002 and MS5002 gas turbine are cylindrical cans, approximately 10.5 inches (27 cm) in diameter. A single fuel nozzle is centered at the inlet to each can and produces a swirl stabilized diffusion flame. The walls of the cans are louvered for cooling, and contain an array of mixing and dilution holes that provide the air needed to complete combustion and dilute the burned gas to the desired turbine inlet temperature. The MS3002 turbine is equipped with six combustor cans, while the MS5002 turbine is equipped with twelve combustors. The new, reduced NOx emissions combustors (referred to as a “lean head end”, or LHE, combustors) retain all of the key features of the conventional combustors; the only major difference is the arrangement of the mixing and dilution holes in the cylindrical combustor cans. By optimizing the number, diameter, and location of these holes, NOx emissions can be reduced considerably. Minor changes are also sometimes made to the combustor cap. The materials of construction, pressure drop, and fuel nozzle are all unchanged. The differences in NOx emissions between the standard and LHE combustors, as well as the variations in NOx emissions with firing temperature, are well correlated using turbulent flame length arguments. Details of this correlation are presented.

Comparison of Numerical Combustion Models for Hydrogen and Hydrogen-Rich Syngas Applied for Dry-Low-NOx-Micromix-Combustion

2016 ◽  
Author(s):  
H. H.-W. Funke ◽  
N. Beckmann ◽  
J. Keinz ◽  
S. Abanteriba
Keyword(s):  
Reaction Mechanism ◽  
Gas Turbines ◽  
Combustion Process ◽  
Computational Effort ◽  
Hydrogen Combustion ◽  
Combustion Stability ◽  
Research Approach ◽  
Pure Hydrogen ◽  
Nox Emissions ◽  
Combustion Models

The Dry-Low-NOx (DLN) Micromix combustion technology has been developed as low emission combustion principle for industrial gas turbines fueled with hydrogen or syngas. The combustion process is based on the phenomenon of jet-in-crossflow-mixing. Fuel is injected perpendicular into the air-cross-flow and burned in a multitude of miniaturized, diffusion-like flames. The miniaturization of the flames leads to a significant reduction of NOx emissions due to the very short residence time of reactants in the flame. In the Micromix research approach, CFD analyses are validated towards experimental results. The combination of numerical and experimental methods allows an efficient design and optimization of DLN Micromix combustors concerning combustion stability and low NOx emissions. The paper presents a comparison of several numerical combustion models for hydrogen and hydrogen-rich syngas. They differ in the complexity of the underlying reaction mechanism and the associated computational effort. For pure hydrogen combustion a one-step global reaction is applied using a hybrid Eddy-Break-up model that incorporates finite rate kinetics. The model is evaluated and compared to a detailed hydrogen combustion mechanism derived by Li et al. including 9 species and 19 reversible elementary reactions. Based on this mechanism, reduction of the computational effort is achieved by applying the Flamelet Generated Manifolds (FGM) method while the accuracy of the detailed reaction scheme is maintained. For hydrogen-rich syngas combustion (H2-CO) numerical analyses based on a skeletal H2/CO reaction mechanism derived by Hawkes et al. and a detailed reaction mechanism provided by Ranzi et al. are performed. The comparison between combustion models and the validation of numerical results is based on exhaust gas compositions available from experimental investigation on DLN Micromix combustors. The conducted evaluation confirms that the applied detailed combustion mechanisms are able to predict the general physics of the DLN-Micromix combustion process accurately. The Flamelet Generated Manifolds method proved to be generally suitable to reduce the computational effort while maintaining the accuracy of detailed chemistry. Especially for reaction mechanisms with a high number of species accuracy and computational effort can be balanced using the FGM model.

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.

Oxidation Behavior of LTA/YSZ Intermixed Layer Coating

2018 ◽  
pp. 107-130
Author(s):  
Pritee Purohit ◽  
Shashikant T. Vagge
Keyword(s):  
Gas Turbines ◽  
Operating Conditions ◽  
Inlet Temperature ◽  
Power Generators ◽  
Industrial Gas Turbines ◽  
The Mean ◽  
Aero Engines ◽  
Industrial Gas Turbine ◽  
Day By Day ◽  
Very High

This chapter describes how for power generators like gas turbines and aero engines, the economic and environmental challenges are increasing day by day for producing electricity more efficiently. The efficiency of power generators can be increased by changing its operating conditions like inlet temperature and procedure. Currently, the inlet temperature to the industrial gas turbine is reaching up to 1400°C. Also, in aero engines, the ring temperature reaches around 1550°C. Therefore, the coatings used in aero engine applications undergo short duration thermal cycles at very high temperature. The mean metal temperatures reach around 950°C and can increase up to 1100°C. But in industrial gas turbines, it varies from 800 to 950°C. Operating temperature of industrial gas turbines slowly reaches to maximum and ideally remains constant for thousands of hours, unlike aero engines.

Adaptive Control of Microgas Turbine for Engine Degradation Compensation

2020 ◽  
Vol 142 (4) ◽  
Author(s):  
Valentina Zaccaria ◽  
Mario L. Ferrari ◽  
Konstantinos Kyprianidis
Keyword(s):  
Adaptive Control ◽  
Gas Turbine ◽  
Gas Turbines ◽  
High Reliability ◽  
Energy Conversion Efficiency ◽  
Health Condition ◽  
Effective Control ◽  
Inlet Temperature ◽  
Or Efficiency ◽  
Industrial Gas Turbines

Abstract Microgas turbine (MGT) engines in the range of 1–100 kW are playing a key role in distributed generation applications, due to the high reliability and quick load following that favor their integration with intermittent renewable sources. Micro-combined heat and power (CHP) systems based on gas turbine technology are obtaining a higher share in the market and are aiming at reducing the costs and increasing energy conversion efficiency. An effective control of system operating parameters during the whole engine lifetime is essential to maintain desired performance and at the same time guarantee safe operations. Because of the necessity to reduce the costs, fewer sensors are usually available than in standard industrial gas turbines, limiting the choice of control parameters. This aspect is aggravated by engine aging and deterioration phenomena that change operating performance from the expected one. In this situation, a control architecture designed for healthy operations may not be adequate anymore, because the relationship between measured parameters and unmeasured variables (e.g., turbine inlet temperature (TIT) or efficiency) varies depending on the level of engine deterioration. In this work, an adaptive control scheme is proposed to compensate the effects of engine degradation over the lifetime. Component degradation level is monitored by a diagnostic tool that estimates performance variations from the available measurements; then, the information on the gas turbine health condition is used by an observer-based model predictive controller to maintain the machine in a safe range of operation and limit the reduction in system efficiency.

Test Validation of Flamelet Model Predictions of NOx

1999 ◽  
Author(s):  
Yu. Buriko ◽  
V. Zakharov ◽  
A. Belokon ◽  
G. Opdyke
Keyword(s):  
Gas Turbines ◽  
Prediction Method ◽  
Inlet Temperature ◽  
Nox Emissions ◽  
Load Curve ◽  
Flamelet Model ◽  
Numerical Predictions ◽  
Air Supply ◽  
Model Predictions ◽  
The Relationship

Calculations of NOx emissions were made for the original high pressure combustor and for the original and a modified design of the low pressure combustor used in a Compressed Air Energy Storage (CAES) plant. All were typical diffusion flame combustors. Since a CAES plant has an independent air supply, the relationship between combustor inlet temperature and pressure is not typical for gas turbines, and the pressure level for the HP combustor is unusually high (up to 4.5 MPa). Vitiated air from HP combustor exhaust is used as combustion air in the LP combustor. The NOx emissions prediction method, which was used, for calculations is based on a flamelet model which takes detailed kinetic schemes for fuel oxidation, NOx generation and turbulence/chemistry interaction into account. Site measurements over the entire load curve confirmed the numerical predictions for both the original combustors and the newly developed LP combustor design.

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.

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