Development of Gas Turbine Combustion Tuning Technology Using Six Sigma Tools

2012 ◽  
Author(s):  
Min Chul Lee ◽  
Kwang Ick Ahn ◽  
Youngbin Yoon
Keyword(s):  
Optimum Condition ◽  
Gas Turbine ◽  
Six Sigma ◽  
Nox Reduction ◽  
Current Status ◽  
Nox Emissions ◽  
Control Parameters ◽  
Tuning Method ◽  
Plant Operations ◽  
Gas Turbine Combustion

A conventional combustion tuning method for a gas turbine needs more than 24 hours with lots of human labor. In addition it is hard to certify whether the plant is optimized because the conventional tuning is based on human decisions and subjective empirical data over a long time. In this study we developed a combustion tuning technology using six sigma tools (CTSS) to effectively meet the increasingly stringent NOx regulations and to save combustion tuning time. CTSS was conducted in five steps—define-identify-design-optimize-verify (DIDOV). First, the NOx reduction target was defined (Step 1, define), the current status of the plant was diagnosed (Step 2, identify), and the vital few control parameters to achieve the defined target were determined by analyzing the correlation between the control parameters and NOx emissions (Step 3, design). For the next step, the optimum condition was derived from one of the six sigma tools (Step 4, optimize), and finally the optimum condition was verified by applying the condition to the gas turbine combustion (Step 5, verify). As a result of CTSS, averaged NOx emissions were reduced by more than 70% and the standard deviation was improved by more than 60%. These results show that CTSS is a potential tool for enhanced reliability of plant operations and scientific method for quick and exact combustion tuning.

Premixing Gas and Air to Reduce NOx Emissions With Existing Proven Gas Turbine Combustion Chambers

1986 ◽  
Author(s):  
B. Becker ◽  
P. Berenbrink ◽  
H. Brandner
Keyword(s):  
Gas Turbine ◽  
Nox Reduction ◽  
Combustion Process ◽  
Liquid Fuels ◽  
Nox Emissions ◽  
Combustion Chambers ◽  
Load Range ◽  
Usual Manner ◽  
Low Nox Combustion ◽  
Gas Turbine Combustion

In the case of the burners employed in KWU gas turbine combustion chambers, the entire primary air is supplied through the swirlers associated with the burners. It is thus relatively easy to add natural gas to this air uniformly before it enters the combustion zone. This results in a particularly low NOx combustion process provided that the air to fuel ratio is being maintained within a certain range. The supplementary equipment to premix the fuel and air does not affect the burner performance when the fuel is supplied in the conventional way by means of gas or oil nozzles. Consequently, the gas turbine will be started up and loaded in the usual manner. In the high load range the burners are then switched over to premixed combustion operation. A small amount of fuel through the central gas nozzle stabilizes the flame in the case of a sudden load decrease. Combustion chambers already in service can be retrofitted with the new premixing equipment to reduce NOx emissions to about one third of the original values. The combustors can be operated with liquid fuels together with steam or water for NOx reduction in the conventional way.

Kinetics Modeling on NOx Emissions of a Syngas Turbine Combustor Using RQL Combustion Method

2019 ◽  
Author(s):  
Haoyang Liu ◽  
Wenkai Qian ◽  
Min Zhu ◽  
Suhui Li
Keyword(s):  
Gas Turbine ◽  
Residence Time ◽  
Air Flow ◽  
Nox Reduction ◽  
Outlet Temperature ◽  
Nox Emissions ◽  
Gas Turbine Combustor ◽  
Kinetics Modeling ◽  
The Rich ◽  
Nox Control

Abstract To avoid flashback issues of the high-H2 syngas fuel, current syngas turbines usually use non-premixed combustors, which have high NOx emissions. A promising solution to this dilemma is RQL (rich-burn, quick-mix, lean-burn) combustion, which not only reduces NOx emissions, but also mitigates flashback. This paper presents a kinetics modeling study on NOx emissions of a syngas-fueled gas turbine combustor using RQL architecture. The combustor was simulated with a chemical reactor network model in CHEMKIN-PRO software. The combustion and NOx formation reactions were modeled using a detailed kinetics mechanism that was developed for syngas. Impacts of combustor design/operating parameters on NOx emissions were systematically investigated, including combustor outlet temperature, rich/lean air flow split and residence time split. The mixing effects in both the rich-burn zone and the quick-mix zone were also investigated. Results show that for an RQL combustor, the NOx emissions initially decrease and then increase with combustor outlet temperature. The leading parameters for NOx control are temperature-dependent. At typical modern gas turbine combustor operating temperatures (e.g., < 1890 K), the air flow split is the most effective parameter for NOx control, followed by the mixing at the rich-burn zone. However, as the combustor outlet temperature increases, the impacts of air flow split and mixing in the rich-burn zone on NOx reduction become less pronounced, whereas both the residence time split and the mixing in the quick-mix zone become important.

Parametric Studies of Gas Turbine Combustion NOx Emissions Using KIVA With a Reduced Mechanism

2000 ◽  
Author(s):  
K. Su ◽  
C. Q. Zhou
Keyword(s):  
Gas Turbine ◽  
Chemical Mechanism ◽  
Inlet Pressure ◽  
Fuel Spray ◽  
Injection Velocity ◽  
Inlet Temperature ◽  
Nox Emissions ◽  
Wide Range ◽  
Mean Diameter ◽  
Gas Turbine Combustion

Abstract A numerical study was conducted to determine the effects of combustion condition parameters, including inlet temperature and pressure, fuel spray characteristics on NOx emissions in gas turbine combustion using the KIVA-3V code. Log-normal spray distribution was assumed for the simulation of real fuel spray distributions at injection. A simplified mechanism with 17-species and 26-step was employed for chemical reactions of Jet A in a formula of C12H23. A sector model of a typical annular combustor was used in calculations. Flow fields and temperature distributions were analyzed. A wide range of operating condition was varied with the inlet pressure from 0.1 to 2.0 MPa, inlet temperature from 400 to 900 K, and overall fuel/air ratio from 0.012 to 0.08. The results reasonably agreed with those from experimental data and Chemkin modeling, which demonstrates the applicability of KIVA-3V and the chemical mechanism to the predictions of NOx emissions. With respect to the inlet temperature, NOx productions show a trend of monotone increasing. As the inlet pressure increases, NOx emissions increase at the beginning and then decrease. The droplet mean diameter as well as injection velocity and angle were independently varied to distinguish the separate effects of variables involved. It is found that the NOx emissions decrease with the Sauter mean diameter, but increase with the injection velocity and angle of fuel sprays. It appears that KIVA-3V code can be a valuable tool for the development of low emission combustors.

Pollutants From Methane Fueled Gas Turbine Combustion

1973 ◽  
Vol 95 (2) ◽  
pp. 97-104
Author(s):  
P. G. Parikh ◽  
R. F. Sawyer ◽  
A. L. London
Keyword(s):  
Gas Turbine ◽  
Liquid Fuels ◽  
Hydrocarbon Emissions ◽  
Nox Emissions ◽  
Gas Composition ◽  
Combustion System ◽  
Piston Engine ◽  
Primary Zone ◽  
Low Levels ◽  
Gas Turbine Combustion

In view of the greater flexibility of a gas turbine combustion system design as compared to that for a piston engine, control of NOx emissions even while keeping the CO and hydrocarbon emissions at very low levels appears feasible. Factors influencing the production of these pollutants in a methane fueled gas turbine type combustor are studied in this investigation by analyzing the gas samples taken at various locations within the combustor. Increasing the homogeneity of the primary zone gas composition by using gaseous or prevaporized liquid fuels is found to be an effective way to reduced NOx emissions.

NOx Reduction Strategy in GE10 Hydrogen-Fuelled Heavy Duty Gas Turbine

2008 ◽  
Author(s):  
Peter Benovsky ◽  
Iarno Brunetti ◽  
Stefano Sigali ◽  
Christine Leroy ◽  
Paolo Gheri ◽  
...  
Keyword(s):  
Power Plant ◽  
Gas Turbine ◽  
High Efficiency ◽  
Nox Reduction ◽  
Second Phase ◽  
Pure Hydrogen ◽  
Nox Emissions ◽  
Cfd Model ◽  
Correct Operation ◽  
North East

In December 2006 Enel promoted a project oriented towards Environment and Innovation including the development of zero emission plants. The hydrogen project foresees the construction of a 11 MWe hydrogen-fed gas turbine able to couple high efficiency (fuel utilization) with low nitrogen-oxide emissions. The project (partly funded by Regione Veneto, a local authority in the North-East of Italy), will be built at Enel’s coal-fired Fusina Power Plant [1]. The aim of a first demonstrative phase is to verify the correct operation of the gas turbine supplied by pure hydrogen and to acquire know-how of hydrogen combustion, safety aspects and control technologies in gas turbine cycles. In the second phase, the goal will be to optimize the combustion technology, paying particular attention to NOx emissions. To make hydrogen suitable for the electricity generation in an environmentally compatible manner, Enel is developing the Fusina’s experimental power plant project. Since currently no commercial hydrogen burners are suitable for gas turbine power plants, both Enel and Nuovo Pignone are investigating feasible solutions for a hydrogen-fuelled low-NOx diffusion burner design. In this context, this paper presents the results from a CFD analysis showing the NOx reduction based on steam injection and burner minor modifications. An initial model with a coarse mesh and simple aerodynamic treatment was used to evaluate the NOx emissions with varying amount of steam injected into the combustion chamber. In the view of the following experimental campaign, some solutions have been selected after an initial tuning of the CFD model. Furthermore, a second CFD model based on a finer mesh and a detailed geometry discretization will enable a more precise investigation of the fluidynamic field. Results of the numerical model, which simulates a GE10 gas turbine combustor fuelled with pure hydrogen, are presented and compared with experimental tests at full scale and full pressure conditions.

Premixed Pilot Flames for Improved Emissions and Flexibility in a Heavy Duty Gas Turbine Combustion System

2015 ◽  
Author(s):  
William D. York ◽  
Bryan W. Romig ◽  
Michael J. Hughes ◽  
Derrick W. Simons ◽  
Joseph V. Citeno
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Hydrogen Gas ◽  
Operating Conditions ◽  
Nox Emissions ◽  
Combustion System ◽  
Heavy Duty ◽  
Low Load ◽  
Gas Turbine Combustion ◽  
Base Load

Operators of heavy duty gas turbines desire more flexibility of operation in compliance with increasingly stringent emissions regulations. Delivering low NOx at base load operation, while at the same time meeting aggressive startup, shutdown, and part load requirements for NOx, CO, and unburned hydrocarbons is a challenge that requires novel solutions in the framework of lean premixed combustion systems. The DLN2.6+ combustion system, first offered by the General Electric Company (GE) in 2005 on the 9F series gas turbines for the 50 Hz market, has a proven track record of low emissions, flexibility, and reliability. In 2010, GE launched a program to incorporate the DLN2.6+ into the 7F gas turbine model. The primary driver for the introduction of this combustion system into the 60 Hz market was to enable customers to capitalize on opportunities to use shale gas, which may have a greater Wobbe range and higher reactivity than traditional natural gas. The 7F version of the DLN2.6+ features premixed pilot flames on the five outer swirl-stabilized premixing fuel nozzles (“swozzles”). The premixed pilots have their roots in the multitube mixer technology developed by GE in the US Department of Energy Hydrogen Gas Turbine Program. A fraction of air is extracted prior to entering the combustor and sent to small tubes around the tip of the fuel nozzle centerbody. A dedicated pilot fuel circuit delivers the gas fuel to the pilot tubes, where it is injected into the air stream and given sufficient length to mix. Since the pilot flames are premixed, they contribute lower NOx emissions than a diffusion pilot, but can still provide enhanced main circuit flame stability at low-load conditions. The pilot equivalence ratio can be optimized for the specific operating conditions of the gas turbine. This paper presents the development and validation testing of the premixed pilots, which were tested on E-class and F-class gas turbine combustion system rigs at GE Power & Water’s Gas Turbine Technology Lab. A 25% reduction in NOx emissions at nominal firing temperature was demonstrated over a diffusion flame pilot, translating into more than 80% reduction in CO emissions if increased flame temperature is employed to hold constant NOx. On the new 7F DLN2.6+, the premixed pilots have enabled modifications to the system to reduce base load NOx emissions while maintaining similar gas turbine low-load performance and bringing a significant reduction in the combustor exit temperature at which LBO occurs, highlighting the stability the pilot system brings to the combustor without the NOx penalty of a diffusion pilot. The new combustion system is scheduled to enter commercial operation on GE 7F series gas turbines in 2015.

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