Laboratory Investigations of Low-Swirl Injectors Operating With Syngases

2008 ◽  
Author(s):  
David Littlejohn ◽  
Robert K. Cheng ◽  
D. R. Noble ◽  
Tim Lieuwen
Keyword(s):  
Gas Turbines ◽  
Power Plants ◽  
Elevated Temperatures ◽  
Turbulent Flame ◽  
Flame Temperature ◽  
Lean Premixed Combustion ◽  
Gaseous Fuels ◽  
Swirl Injectors ◽  
Log Linear ◽  
Reduced Scale

The low-swirl injector (LSI) is a lean premixed combustion technology that has the potential for adaptation to fuel-flexible gas turbines operating on a variety of fuels. The objective of this study is to gain a fundamental understanding of the effect of syngas on the LSI flame behavior, the emissions and the flowfield characteristics for its adaptation to the combustion turbines in IGCC clean coal power plants. The experiments were conducted in two facilities. Open laboratory flames generated by a full size (6.35 cm) LSI were used to investigate the lean-blow off limits, emissions, and the flowfield characteristics. Verification of syngas operation at elevated temperatures and pressures were performed with a reduced scale (2.54 cm) LSI in a small pressurized combustion channel. The results show that the basic LSI design is amenable to burning syngases with up to 60% H2. Syngases with high H2 concentration have lower lean blow-off limits. From PIV measurements, the flowfield similarity behavior and the turbulent flame speeds of syngases flames are consistent with those observed in hydrocarbon and pure or diluted hydrogen flames. The NOx emissions from syngas flames show log-linear dependency on the adiabatic flame temperature and are comparable to those reported for the gaseous fuels reported previously. Successful firing of the reduced-scale LSI at 330 < T < 446° F and 8 atm verified the operability of this concept at gas turbine conditions.

Laboratory Investigations of Low-Swirl Injectors Operating With Syngases

2009 ◽  
Vol 132 (1) ◽  
Author(s):  
David Littlejohn ◽  
Robert K. Cheng ◽  
D. R. Noble ◽  
Tim Lieuwen
Keyword(s):  
Gas Turbines ◽  
Power Plants ◽  
Elevated Temperatures ◽  
Turbulent Flame ◽  
Flame Temperature ◽  
Combined Cycle ◽  
Integrated Gasification Combined Cycle ◽  
Lean Premixed Combustion ◽  
Log Linear ◽  
Reduced Scale

The low-swirl injector (LSI) is a lean premixed combustion technology that has the potential for adaptation to fuel-flexible gas turbines operating on a variety of fuels. The objective of this study is to gain a fundamental understanding of the effect of syngas on the LSI flame behavior, the emissions, and the flowfield characteristics for adaptation to the combustion turbines in integrated gasification combined cycle clean coal power plants. The experiments were conducted in two facilities. Open atmospheric laboratory flames generated by a full size (6.35 cm) LSI were used to investigate the lean blow-off limits, emissions, and the flowfield characteristics. Verification of syngas operation at elevated temperatures and pressures were performed with a reduced scale (2.54 cm) LSI in a small pressurized combustion channel. The results show that the basic LSI design is amenable to burning syngases with up to 60% H2. Syngases with high H2 concentration have lower lean blow-off limits. From particle image velocimetry measurements, the flowfield similarity behavior and the turbulent flame speeds of syngases flames are consistent with those observed in hydrocarbon and pure or diluted hydrogen flames. The NOx emissions from syngas flames show log-linear dependency on the adiabatic flame temperature and are comparable to those reported for the gaseous fuels reported previously. Successful firing of the reduced-scale LSI at 450 K<T<505 K and 8 atm verified the operability of this concept at gas turbine conditions.

Laboratory Study of Premixed H2-Air and H2-N2-Air Flames in a Low-Swirl Injector for Ultra-Low Emissions Gas Turbines

2007 ◽  
Author(s):  
R. K. Cheng ◽  
D. Littlejohn
Keyword(s):  
Gas Turbines ◽  
Power Plants ◽  
Turbulent Flame ◽  
Combustion Method ◽  
Combined Cycle ◽  
Integrated Gasification Combined Cycle ◽  
Swirl Number ◽  
Turbulent Flame Speed ◽  
Swirl Injectors ◽  
Integrated Gasification

The objective of this study is to conduct laboratory experiments on Low-swirl injectors (LSI) to obtain the basic information for adapting LSI to burn H2 and diluted H2 fuels that will be utilized in the gas turbines of the Integrated Gasification Combined Cycle (IGCC) coal power plants. The LSI is a novel ultra-low emission dry-low NOx combustion method that has been developed for gas turbines operating on natural gas. It is being developed for fuel-flexible turbines burning a variety of hydrocarbon fuels, bio-mass gases and refinery gases. Adaptation of the LSI to accept H2 flames is guided by an analytical expression derived from the flowfield characteristics and the turbulent flame speed correlation. Evaluation of the operating regimes of nine LSI configurations for H2 shows an optimum swirl number of 0.51 which is slightly lower than the swirl number of 0.54 for the hydrocarbon LSI. Using Particle Image Velocimetry the flowfields of 32 premixed H2-air and H2-N2-air flames were measured. The turbulent flame speeds deduced from PIV show linear correlation with turbulence intensity. The correlation constant for H2 is 3.1 and is higher than the 2.14 value for hydrocarbons. Analysis of velocity profiles confirms that the nearfield flow features of the H2 flames are self-similar. These results demonstrate that the basic LSI mechanism is not affected by the differences in the properties of H2 and hydrocarbon flames and support the feasibility of the LSI concept for hydrogen fueled gas turbines.

Low Load Operation Range Extension by Autothermal On-Board Syngas Generation

2017 ◽  
Vol 140 (4) ◽  
Author(s):  
Max H. Baumgärtner ◽  
Thomas Sattelmayer
Keyword(s):  
Gas Turbines ◽  
Power Plants ◽  
Renewable Energy Sources ◽  
Flame Temperature ◽  
Combined Cycle ◽  
Sudden Increase ◽  
Gaseous Emissions ◽  
Fuel Processor ◽  
Burn Out ◽  
Unburned Hydrocarbons

The increasing amount of volatile renewable energy sources drives the necessity of flexible conventional power plants to compensate for fluctuations of the power supply. Gas turbines in a combined cycle power plant (CCPP) adjust the power output quickly but a sudden increase of CO and unburned hydrocarbons emissions limits their turn-down ratio. To extend the turn-down ratio, part of the fuel can be processed to syngas, which exerts a higher reactivity. An autothermal on-board syngas generator in combination with two different burner concepts for natural gas (NG) and syngas mixtures is presented in this study. A mixture of NG, water vapor, and air reacts catalytically in an autothermal reactor test rig to form syngas. At atmospheric pressure, the fuel processor generates syngas with a hydrogen content of −30 vol % and a temperature of 800 K within a residence time of 200 ms. One concept for the combustion of NG and syngas mixtures comprises a generic swirl stage with a central lance injector for the syngas. The second concept includes a central swirl stage with an outer ring of jets. The combustion is analyzed for both concepts by OH*-chemiluminescence, lean blow out (LBO) limit, and gaseous emissions. The central lance concept with syngas injection exhibits an LBO adiabatic flame temperature that is 150 K lower than in premixed NG operation. For the second concept, an extension of almost 200 K with low CO emission levels can be reached. This study shows that autothermal on-board syngas generation is feasible and efficient in terms of turn-down ratio extension and CO burn-out.

Measurement and Abatement of PM Emitted by Stationary Gas Turbines: Experience Gained With Different Fuels and Combustor Types

2018 ◽  
Author(s):  
Aristotelis Komodromos ◽  
George Moniatis ◽  
Frixos Kontopoulos ◽  
George Zaimis ◽  
Matthieu Vierling ◽  
...  
Keyword(s):  
Gas Turbines ◽  
Liquid Fuel ◽  
Power Plants ◽  
Water Injection ◽  
Liquid Fuels ◽  
Injection System ◽  
Joint Work ◽  
Gaseous Fuels ◽  
Scale Test ◽  
Combustion Systems

Whichever the type of combustion installation, liquid fuels burned in gas turbines tend to generate particulate matter (PM) emissions, which consist in soot only or in ash plus soot, according to their ash-free or ash-forming character. Standard diffusion flame combustion systems are known as “universal” combustors, capable to burn both ash-free (naphtha, light and heavy distillates) and ash-forming (crude and heavy) fuels. In contrast, DLN systems are designed to burn gaseous fuels and light distillates. PMs in the range of a few parts per million represent a solid micropollutant, the measurement and abatement of which creates specific technical challenges. In order to fully characterize soot emission and investigate their reduction, GE has undertaken a multi-year investigation program covering (i) an exploratory engineering study starting from the EN13284-1 standard and (ii) the testing of a number of inorganic oxidation catalysts used in the form of fuel additives (“soot inhibitors”). In this framework, a joint work involving GE and Electricity Authority of Cyprus has been conducted in the first half of 2017 and a full-scale test plan has been performed at the Vasilikos power plant in Cyprus, involving a Frame 6F.03 DLN2.6 that burns light distillate oil and is equipped with a DeNOx water injection system. Four types of soot inhibitor additives: cerium (IV) and (III), iron (III) and (II) were tested. This paper reviews the results of this field test and compares them with data previously acquired at other power plants featuring different liquid fuels and combustion systems. Its goal is to provide the gas turbine community with a better understanding of PM emissions and their abatement using various soot inhibitor candidates, in function of liquid fuel type and combustion system.

Micromixers and Hydrogen Enrichment: The Future Combustion Technology in Zero-Emission Power Plants

2020 ◽  
Author(s):  
Muzafar Hussain ◽  
Ahmed Abdelhafez ◽  
Medhat A. Nemitallah ◽  
Mohamed A. Habib
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Power Plants ◽  
Flame Temperature ◽  
Fuel Mixture ◽  
Flame Stability ◽  
Emission Power ◽  
Adiabatic Flame Temperature ◽  
Combustion Technology ◽  
Zero Emission

Abstract The stable and flexible micromixer (MM) gas-turbine technology is coupled with hydrogen (H2) enrichment to present an oxy-methane combustor that can sustain highly diluted flames for application in the Allam cycle for zero-emission power production. MMs have never been tested under oxy-fuel conditions, which highlights the novelty of the present study. The operability window was quantified over ranges of fuel hydrogen fraction (HF) and oxidizer oxygen fraction OF. The MM showed superior stability, allowing for reducing OF down to 21% (by vol.) without H2 enrichment, which satisfies the dilution requirements (23%) of the primary reaction zone within the Allam-cycle combustor. By comparison, swirl-based burners from past studies exhibited a ∼30% minimum threshold. Enriching the fuel with H2 boosted flame stability and allowed for reducing OF further down to a record-low value of 13% at HF = 65% (by vol.) in fuel mixture. Under these highly diluted conditions, the adiabatic flame temperature is 990°C (1800°F), which is substantially lower than the lean blowout limit of most known technologies of lean premixed air-fuel combustion in gas-turbine applications. The results also showed that H2 enrichment has minimal effect on the adiabatic flame temperature and combustor power density (MW/m3/atm), which facilitates great operational flexibility in adjusting HF to sustain flame stability without influencing the Allam cycle peak temperature or affecting the turbine health. MM combustion with H2 enrichment is thus a recommended technology for controlled-emission, fuel/oxidizer-flexible combustion in gas turbines.

Exploring Use of Hydrogen for Extending Operability of a Full-Scale Annular Combustor

2021 ◽  
Author(s):  
Candy Hernandez ◽  
Vincent McDonell ◽  
Jacob Delimont ◽  
Gareth Oskam ◽  
Michael Ramotowski
Keyword(s):  
Natural Gas ◽  
Gas Turbines ◽  
Power Plants ◽  
Elevated Temperatures ◽  
Chemical Reactor ◽  
Combined Heat And Power ◽  
Full Scale ◽  
Design Tool ◽  
Annular Combustor ◽  
Reactor Network

Abstract In anticipation of increased use of hydrogen as a means of decarbonizing future power generation used widely in combined heat and power plants, studies are underway to understand how hydrogen impacts operability and emissions from existing low emission gas turbines. In the current study, a full-scale annular combustor is used to study how added hydrogen to methane (as a proxy for natural gas) impacts lean blow-off limits. Of particular interest is understanding if hydrogen can be used strategically to extend low emissions operation at lower load. This would facilitate use of gas turbines to offset intermittent renewable power which is becoming increasing integrated into microgrid environments where combined heat and power system are prevalent. A combined experimental and numerical approach is taken. Tests were carried out at Southwest Research Institute using a full-scale annular combustor test rig at elevated temperatures and atmospheric pressure. The individual fuel injectors used were piloted injectors based on natural gas injectors used in practice. Various blends of hydrogen and methane were tested for different scaled load conditions and different pilot to main fuel splits. Besides identifying the overall equivalence ratio at blow-off, measurements also included temperature uniformity at the exit plane and imaging of the reaction. To complement and extend the study a chemical reactor network approach was also applied. The reactor network was initially validated on a prior study involving use of a piloted model combustor. The reactor network was applied to the current configuration and further tuned to align with the measured data. The agreement between the reactor network blow-off and measured blow-off was reasonable. The validated reactor network was then used in combination with a statistically designed simulation matrix to derive a design tool. The tool is then used to estimate other performance features including CO emissions near LBO and the impacts of ambient humidity and the presence of higher hydrocarbons typically found in natural gas. The design tool quantifies the extent to which hydrogen content and pilot percentage can extended part load operability for the full annular combustor system.

Experimental and Numerical Investigations of Low-Swirl Multi-Nozzle Combustion in a Lean Premixed Combustor

2014 ◽  
Author(s):  
Weijie Liu ◽  
Bing Ge ◽  
Yinshen Tian ◽  
Yongwen Yuan ◽  
Shusheng Zang ◽  
...  
Keyword(s):  
Gas Turbines ◽  
Equivalence Ratio ◽  
Flame Temperature ◽  
Main Reaction ◽  
Nox Emissions ◽  
Lean Premixed ◽  
Planar Laser ◽  
Reaction Zones ◽  
Promising Solution ◽  
Log Linear

This paper presents large-eddy simulations (LES) and laser diagnostic experiments of low-swirl lean premixed methane/air flames in a multi-nozzle combustor including five nozzles with the same structure. OH Planar Laser Induced Fluorescence (PLIF) is used to observe flame shapes and identify main reaction zones. NOx and CO emissions are also recorded during the experiment. The flows and flames are studied at different equivalence ratios ranging from 0.5 to 0.8, while the inlet velocity is fixed at 6.2 m/s. Results show that the neighboring swirling flows interact with each other, generating a highly turbulent mixing zone where intensive reactions take place. The flame is stabilized above the nozzle rim and its liftoff height decreases with increasing equivalence ratio. The center flow is confined and distorted by the neighboring flows, resulting in instabilities of the center flame. Mean OH radical images reveals that the center nozzle flame is extinguished when equivalence ratio is equals to 0.5, which is successfully predicted by LES. In addition, NOx emissions show log-linear dependency on the adiabatic flame temperature, while the CO emissions remain lower than 10 ppm. NOx emissions for multi-nozzle flame are less sensitive to the flame temperature than that for single nozzle. These results demonstrate that the low-swirl multi-nozzle concept is a promising solution to achieve stable combustion with ultra-low emissions in gas turbines.

scholarly journals Transpiration Air Protected Turbine Blades: An Effective Concept to Achieve High Temperature and Erosion Resistance for Gas Turbines Operating in an Aggressive Environment

1978 ◽  
Author(s):  
R. Raj ◽  
S. L. Moskowitz
Keyword(s):  
High Temperature ◽  
Gas Turbine ◽  
Gas Turbines ◽  
Power Plants ◽  
Erosion Resistance ◽  
Turbine Blades ◽  
Future Generation ◽  
Combined Cycle ◽  
Gaseous Fuels ◽  
Cooled Blade

The future generation is looking forward to the use of gas turbine inlet temperatures as high as 3000 F (1650 C) with attendant thermal efficiencies of from 40 to 50 percent in combined cycle electric power plants. In addition to the use of high temperature for improved efficiency, the national needs, due to scarcity of oil and natural gas, will heavily stress the use of coal as a fuel. The particulate from combustion of coal derived liquid and gaseous fuels, even after employing hot gas cleanup systems, may damage conventional turbine blades and thus reduce turbine life. This paper is intended to show how a transpiration-cooled blade can cope with both of the foregoing problems simultaneously. The fundamental aspects of the transpiration-cooled blade technology will also be explained. Experimental results using this design concept indicate that significant erosion resistance is feasible for gas turbine blading in the near future.

scholarly journals High Temperature Microelectromechanical Systems Using Piezoelectric Aluminum Nitride

2014 ◽  
Vol 2014 (HITEC) ◽  
pp. 000040-000046
Author(s):  
Benjamin A. Griffin ◽  
Scott D. Habermehl ◽  
Peggy J. Clews
Keyword(s):  
Thin Films ◽  
High Temperature ◽  
Aluminum Nitride ◽  
Mechanical Strength ◽  
Gas Turbines ◽  
Power Plants ◽  
Microelectromechanical Systems ◽  
Elevated Temperatures ◽  
Coefficient Of Thermal Expansion ◽  
Temperature Limit

We report on the efforts at Sandia National Laboratories to develop high temperature capable microelectromechanical systems (MEMS). MEMS transducers are pervasive in today's culture, with examples found in cell phones, automobiles, gaming consoles, and televisions. There is currently a need for MEMS transducers that can operate in more harsh environments, such as automobile engines, gas turbines, nuclear and coal power plants, and petroleum and geothermal well drilling. Our development focuses on the coupling of silicon carbide (SiC) and aluminum nitride (AlN) thin films on SiC wafers to form a MEMS material set capable of temperatures beyond 1000°C. SiC is recognized as a promising material for high temperature capable MEMS transducers and electronics because it has the highest mechanical strength of semiconductors with the exception of diamond and its upper temperature limit exceeds 2500°C, where it sublimates rather than melts. Most transduction schemes in SiC are focused on measuring changes in capacitance or resistance, which require biasing or modulation schemes that can withstand elevated temperatures. Instead, we are coupling temperature hardened, micro-scale SiC mechanical components with piezoelectric AlN thin films. AlN is a non-ferroelectric piezoelectric material, enabling piezoelectric transduction at temperatures exceeding 1000°C. AlN is a favorable MEMS material due to its high thermal, electrical, and mechanical strength. It is also closely matched to SiC for coefficient of thermal expansion.

Using Fresh Air in Windbox Repowering of Existing Steam Power Plants

2007 ◽  
Author(s):  
V. Nayyeri ◽  
P. Asna Ashary
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Power Plants ◽  
Flame Temperature ◽  
Heat Transfer Process ◽  
Low Oxygen ◽  
Steam Power ◽  
Steam Power Plants ◽  
Gas Turbine Exhaust ◽  
Turbine Exhaust

Repowering is increasing efficiency and output power of an existing steam power plants by integration them with gas turbine. Several approaches are proposed for repowering regards to condition of existing power plants. One of those approaches which provides opportunity for existing boiler reusing is windbox repowering. In this method, one or several gas turbines are installed near the existing steam unit and the exhaust of gas turbines is used as preheated combustion air for boiler. The main difficulty in integration of gas turbine and boiler is decreasing flame temperature in supplementary combustion of boiler due to low oxygen content of gas turbine exhaust compared with fresh air and its effect on heat transfer process especially in radiative sections. When advanced gas turbines are used in windbox repowering, the fresh air should be used for increasing oxygen due to low oxygen percent. In this study, the effect of using fresh air in wind box repowering will be investigated and two main arrangements, preheating and not preheating of fresh air will be compared. This study shows the advantages of using preheated air for mixing with gas turbine exhaust when advanced gas turbines are used for windbox repowering.

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