Colorless Distributed Combustion (CDC) With Swirl for Gas Turbine Application

2010 ◽  
Author(s):  
Ahmed E. E. Khalil ◽  
Vaibhav K. Arghode ◽  
Ashwani K. Gupta
Keyword(s):  
Gas Turbine ◽  
Fuel Injection ◽  
Hot Spot ◽  
Stability Limit ◽  
High Heat ◽  
Experimental Investigations ◽  
Gas Turbine Combustor ◽  
Swirl Flows ◽  
Thermal Nox ◽  
Colorless Distributed Combustion

Colorless Distributed Combustion (CDC) can provide significant improvement in gas turbine combustor performance. CDC is characterized by uniform thermal field in the entire combustion chamber, thus avoiding hot-spot regions for low NOx emissions (thermal NOx) and significantly improved pattern factor. In this paper, colorless distributed combustion with swirl is investigated in detail to seek the beneficial aspects of CDC and swirl flows with focus on developing ultra low emissions of NO and CO, and much improved pattern factor. Experimental investigations have been performed using a cylindrical combustor with different modes of fuel injection, swirling air injection and gas exit stream location of the combustor. Air was injected tangentially to impart swirl to the flow inside the combustor. Results showed very low levels of NO (∼3PPM) and CO (∼70PPM) emissions at equivalence ratio of 0.7 at a high heat release intensity of 36MW/m3atm with non-premixed mode of combustion. Results have also been obtained on lean stability limit and OH* chemiluminescence under both premixed and non-premixed conditions.

Swirl Effects on Distributed Combustion for Near Zero Emission Gas Turbine Application

2010 ◽  
Author(s):  
Ahmed E. E. Khalil ◽  
Vaibhav K. Arghode ◽  
Ashwani K. Gupta
Keyword(s):  
Gas Turbine ◽  
Fuel Injection ◽  
High Heat ◽  
Spontaneous Ignition ◽  
Experimental Investigations ◽  
Diffusion Combustion ◽  
Swirl Intensity ◽  
Zero Emission ◽  
Colorless Distributed Combustion

Previous investigations of Colorless Distributed Combustion (CDC) demonstrated significant improvement in combustor’s performance. CDC is characterized by high recirculation of product gases, fast mixing, spontaneous ignition and distributed reaction, leading to avoidance of hotspots and much lower NOx emissions. In this investigation, CDC is sought with focus on tailored mixture preparation before ignition using swirl and achieving distributed combustion for developing near zero emission combustion under gas turbine combustion conditions. Numerical and experimental investigations have been performed on a cylindrical combustor. Different fuel injection and hot gases exit arrangements have been considered. Air was injected tangentially to produce vortical structure in the flow and produce high swirl intensity. Results obtained show ultra low NO emissions (∼3 PPM) at high heat release intensity of 36 MW/m3-atm at an equivalence ratio (Φ) of 0.6. The role of premixed and diffusion combustion is also examined.

Evaluation of Combustion and Emissions Using Biodiesel and Blends With Kerosene in a Low NOx Gas Turbine Combustor

2010 ◽  
Author(s):  
Hu Li ◽  
Mohamed Altaher ◽  
Gordon E. Andrews
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Equivalence Ratio ◽  
Fuel Injection ◽  
Waste Cooking Oil ◽  
Industrial Applications ◽  
Liquid Fuels ◽  
Gaseous Emissions ◽  
Gas Turbine Combustor ◽  
Industrial Gas Turbines

Biofuels offer reduced CO2 emissions for both industrial and aero gas turbines. Industrial applications are more practical due to low temperature waxing problems at altitude. Any use of biofuels in industrial gas turbines must also achieve low NOx and this paper investigates the use of biofuels in a low NOx radial swirler, as used in some industrial low NOx gas turbines. A waste cooking oil derived methyl ester biodiesel (WME) has been tested on a radial swirler industrial low NOx gas turbine combustor under atmospheric pressure and 600K. The pure WME and its blends with kerosene, B20 and B50 (WME:kerosene = 20:80 and 50:50 respectively), and pure kerosene were tested for gaseous emissions and lean extinction as a function of equivalence ratio. The co-firing with natural gas (NG) was tested for kerosene/biofuel blends B20 and B50. The central fuel injection was used for liquid fuels and wall injection was used for NG. The experiments were carried out at a reference Mach number of 0.017. The inlet air to the combustor was heated to 600K. The results show that B20 produced similar NOx at an equivalence ratio of ∼0.5 and a significant low NOx when the equivalence ratio was increased comparing with kerosene. B50 and B100 produced higher NOx compared to kerosene, which indicates deteriorated mixing due to the poor volatility of the biofuel component. The biodiesel lower hydrocarbon and CO emissions than kerosene in the lean combustion range. The lean extinction limit was lower for B50 and B100 than kerosene. It is demonstrated that B20 has the lowest overall emissions. The co-firing with NG using B20 and B50 significantly reduced NOx and CO emissions.

scholarly journals Response of a Model Gas Turbine Combustor to Variation in Gaseous Fuel Composition

2000 ◽  
Vol 123 (4) ◽  
pp. 824-831 ◽  
Author(s):  
R. M. Flores ◽  
M. M. Miyasato ◽  
V. G. McDonell ◽  
G. S. Samuelsen
Keyword(s):  
Gas Turbine ◽  
Fuel Injection ◽  
Injection System ◽  
Fuel Composition ◽  
Gas Turbine Combustor ◽  
Fuel Distribution ◽  
Air Mixing ◽  
Predominant Factor ◽  
Model Gas Turbine Combustor ◽  
Composition Changes

The effect of fuel composition on performance is evaluated on a model gas turbine combustor designed to mimic key features of practical devices. A flexible fuel injection system is utilized to control the placement of the fuel in the device to allow exploration and evaluation of fuel distribution effects in addition to chemistry effects. Gas blends reflecting the extremes in compositions found in the U.S. are considered. The results illustrate that, for the conditions and configuration studied, both fuel chemistry and fuel air mixing play a role in the performance of the device. While chemistry appears to be the predominant factor in stability, a role is noted in emissions performance as well. It is also found that changes in fuel distribution associated with changes in fuel momentum for fixed firing rate also have an impact on emissions. For the system considered, a strategy for sustaining optimal performance while fuel composition changes is illustrated.

Numerical Simulation of NO Production in Gas-Turbine Combustor With Large-Eddy Simulation Using 2-Scalar Flamelet Approach

2009 ◽  
Author(s):  
Shingo Nishida ◽  
Tomonori Yamamoto ◽  
Kazuhiro Tsukamoto ◽  
Nobuyuki Oshima
Keyword(s):  
Gas Turbine ◽  
Prediction Method ◽  
Calculation Model ◽  
No Production ◽  
Test Model ◽  
Gas Turbine Combustor ◽  
Eddy Simulation ◽  
Higher Temperature ◽  
Thermal Nox ◽  
High Level

Under high temperature combusting environment, very high level of thermal NOx is generated. In order to prevent environmental contamination and pursue more power generation efficiency, we need to build up radically new combustion mode that satisfies both of higher temperature at outlet and lower NOx emissions. To investigate the ability of our numerical prediction method in a practical combustor system, we calculate two combustion modes and predict time-averaged temperature and NOx distribution in the 1700degC class gas-turbine combustor that is a test model fabricated by Mitsubishi Heavy Industries, Ltd. Then, we compare with experimental data to validate and analyze our calculation model. The results show LES and 2-scalar flamelet approach is very effective to predict NOx production in practical gas-turbine combustor.

Non-Premixed and Premixed Colorless Distributed Combustion for Gas Turbine Application

2010 ◽  
Author(s):  
Vaibhav Arghode ◽  
Ashwani K. Gupta
Keyword(s):  
Gas Turbine ◽  
Fuel Injection ◽  
Premixed Combustion ◽  
Spontaneous Ignition ◽  
Combustion Mode ◽  
Acoustic Signatures ◽  
Combustion Modes ◽  
Sound Levels ◽  
Colorless Distributed Combustion ◽  
Gas Recirculation

Non-premixed and premixed modes of Colorless Distributed Combustion (CDC) are investigated for application to gas turbine combustors. The CDC provides significant improvement in pattern factor, reduced NOx emission uniform thermal field in the entire combustion zone for it to be called as a isothermal reactor, and lower sound levels. Basic requirement for CDC is mixture preparation through good mixing between the combustion air and product gases so that the reactants are at much higher temperature to result in hot and diluted oxidant stream at temperatures that are high enough to auto-ignite the fuel and oxidant mixture. With desirable conditions one can achieve spontaneous ignition of the fuel with distributed combustion reactions. Distributed reactions can also be achieved in premixed mode of operation with sufficient entrainment of burned gases and faster turbulent mixing between the reactants. In the present investigation two non-premixed combustion modes and one premixed combustion mode that provide potential for CDC is examined. In all the configurations the air injection port is positioned at the opposite end of the combustor exit, whereas the location of fuel injection ports is changed to give different configurations. The results are compared for global flame signatures, exhaust emissions, acoustic signatures, and radical emissions using experiments and flow field, gas recirculation and mixing using numerical simulations. Ultra low NOx emissions are observed for both the premixed and non-premixed combustion modes, and almost colorless flames (no visible flame color) have been observed for the premixed combustion mode. The non-premixed mode was also provided near colorless distributed combustion. The reaction zone is observed to be significantly different in the two non-premixed modes.

Mixture Preparation Effects on Distributed Combustion for Gas Turbine Applications

2012 ◽  
Vol 134 (3) ◽  
Author(s):  
Ahmed E. E. Khalil ◽  
Ashwani K. Gupta ◽  
Kenneth M. Bryden ◽  
Sang C. Lee
Keyword(s):  
Gas Turbine ◽  
Fuel Injection ◽  
Hot Spot ◽  
Turbine Blades ◽  
Active Species ◽  
Low Noise ◽  
Spontaneous Ignition ◽  
Air Cooling ◽  
Nox Emissions ◽  
Mixing Process

Distributed combustion is now known to provide significantly improved performance of gas turbine combustors. Key features of distributed combustion include uniform thermal field in the entire combustion chamber for significantly improved pattern factor and avoidance of hot-spot regions that promote thermal NOx emissions, negligible emissions of hydrocarbons and soot, low noise, and reduced air cooling requirements for turbine blades. Distributed combustion requires controlled mixing between the injected air, fuel, and hot reactive gasses from within the combustor prior to mixture ignition. The mixing process impacts spontaneous ignition of the mixture to result in improved distributed combustion reactions. Distributed reactions can be achieved in premixed, partially premixed, or nonpremixed modes of combustor operation with sufficient entrainment of hot and active species present in the combustion zone and their rapid turbulent mixing with the reactants. Distributed combustion with swirl is investigated here to further explore the beneficial aspects of such combustion under relevant gas turbine combustion conditions. The near term goal is to develop a high intensity combustor with ultralow emissions of NOx and CO, and a much improved pattern factor and eventual goal of near zero emission combustor. Experimental results are reported for a cylindrical geometry combustor for different modes of fuel injection with emphasis on the resulting pollutants emission. In all the cases, air was injected tangentially to impart swirl to the flow inside the combustor. Ultra low NOx emissions were found for both the premixed and nonpremixed combustion modes for the geometries investigated here. Results showed very low levels of NO (∼10 ppm) and CO (∼21 ppm) emissions under nonpremixed mode of combustion with air preheats at an equivalence ratio of 0.6 and a moderate heat release intensity of 27 MW/m3-atm. Results are also reported on lean stability limits and OH* chemiluminescence under different fuel injection scenarios for determining the extent of distribution combustion conditions. Numerical simulations have also been performed to help develop an understanding of the mixing process for better understanding of ignition and combustion.

Experimental Evaluation of Fuel Injection Configurations for a Lean-Premixed Low NOx Gas Turbine Combustor

1987 ◽  
Author(s):  
Kenneth O. Smith ◽  
F. R. Kurzynske ◽  
Leonard C. Angello
Keyword(s):  
Gas Turbine ◽  
Experimental Evaluation ◽  
Fuel Injection ◽  
Nox Emissions ◽  
Fuel Injector ◽  
Gas Turbine Combustor ◽  
Program Goal ◽  
Preliminary Step ◽  
Gas Fuel ◽  
Design And Testing

The design and testing of three natural gas fuel injector configurations for a low emissions gas turbine combustor are described. The injectors provided varying degrees of fuel/air premixing and permitted an assessment of the degree of premixing necessary to achieve NOx emissions below the program goal of 10 ppm. The work described represents a preliminary step in an effort to develop production-level gas turbine combustor hardware with ultra-low NOx capabilities.

Preliminary Study of Low Emission Gas Turbine Combustor With Airblast Fuel Atomizer

1976 ◽  
Vol 98 (1) ◽  
pp. 15-22
Author(s):  
K. Yamanaka ◽  
K. Nagato
Keyword(s):  
Gas Turbine ◽  
Fuel Injection ◽  
Tube Wall ◽  
Combustion Stability ◽  
Exhaust Emission ◽  
Fuel Injector ◽  
Gas Turbine Combustor ◽  
Low Emission ◽  
New Type ◽  
Preliminary Study

Recent papers describe that an airblast fuel atomizer is very effective for reducing emissions from a gas turbine and this type of fuel injector is being applied to practical engines. This paper deals with the new type of airblast fuel atomizer AFIT which comes from “Airblast Fuel Injection Tube” that makes fuel to break up into droplets by atomizing air at several small holes on the tube wall and fuel is well mixed with atomizing air instantly at the exits of holes. Regarding this AFIT, the fuel spray characteristics, combustion stability which is usually narrow for the combustor with an airblast fuel atomizer at lower engine speeds and exhaust emission levels are experimented and its effectiveness is discussed.

Investigation of the Working Processes in a Gas Turbine Combustor With Steam Injection

2011 ◽  
Author(s):  
Serhiy Serbin ◽  
Anna Mostipanenko ◽  
Igor Matveev
Keyword(s):  
Power Generation ◽  
Nitrogen Oxides ◽  
Gas Turbine ◽  
Geometry Optimization ◽  
Steam Injection ◽  
Experimental Investigations ◽  
Gas Turbine Combustor ◽  
Operation Modes ◽  
Working Processes

Theoretical and experimental investigations of the working processes in a gas turbine combustor with steam injection have been conducted. Selected concept of a gas turbine combustor can provide higher performance, wider turn down ratios, lower emission of nitrogen oxides, demonstrate satisfactory major gravimetric and volumetric parameters. Obtained results and recommendations can be used for the gas turbine combustor operation modes modeling, geometry optimization, prospective propulsion and power generation units design and engineering.

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