Liquid Fuelled Low NOx Radial Swirlers With Central Pilot Combustion

2007 ◽  
Author(s):  
Gordon E. Andrews ◽  
M. N. Kim ◽  
Mike C. Mkpadi ◽  
Sheriff A. Akande
Keyword(s):  
Natural Gas ◽  
Liquid Fuel ◽  
Fuel Injection ◽  
Liquid Fuels ◽  
Lean Combustion ◽  
Auto Ignition ◽  
Primary Zone ◽  
Low Nox Combustion ◽  
The Difference ◽  
Injection Location

Radial swirlers have proved effective in achieving low NOx using natural gas and this work investigates their use with kerosene with and without a central NG pilot. Two kerosene fuel injection locations were compared: at the inlet to the vane passages on the centreline with co-flow injection and 20mm downstream of the 76mm diameter swirler exit through the wall of a 76mm diameter 40mm long discharge duct. Flash back and auto ignition problems cannot occur with the downstream wall fuel injection location. All configurations were also tested with natural gas so that the difference in emissions due to the change from gas to liquid fuel could be established. The results show that ultra low NOx emissions can be achieved for kerosene with vane passage injection and that the use of a central pilot increases the NOx but improves the flame stability and power turndown. However, on liquid fuels the pilot to main flame propagation was not as good as when natural gas was used as the main fuel. Liquid fuel injection at the radial swirler wall outlet was effective but had slightly higher NOx for lean mixtures and worse HC and CO emissions. However, for richer primary zone mixtures the NOx was lower than for vane passage injection and this indicated that rich/lean combustion was occurring, without the uniform mixing and low NOx combustion that occurred with natural gas injection at this location.

Lean/Lean Staged Low NOx Combustion for Near Stoichiometric Gas Turbine Primary Zone Conditions

2001 ◽  
Author(s):  
M. C. Mkpadi ◽  
G. E. Andrews ◽  
I. Khan ◽  
M. N. Mohd Jaafar ◽  
M. Pourkashanian ◽  
...  
Keyword(s):  
Gas Turbine ◽  
Atmospheric Pressure ◽  
Equivalence Ratio ◽  
Fuel Injection ◽  
Nox Emissions ◽  
Two Stage ◽  
Second Stage ◽  
Lean Combustion ◽  
Primary Zone ◽  
Low Nox Combustion

A two-stage lean/lean primary zone at simulated atmospheric pressure gas turbine combustion conditions was shown to give low NOx emissions at atmospheric pressure and 600K inlet temperature. All the combustion air was admitted to the first lean stage, where very lean <5ppm low NOx combustion occurred. A 40mm outlet diameter radial swirler with radial vane passage fuel injection was used in the first stage. After completion of this first stage lean combustion, second stage of fuel injection with no associated air occurred 320mm downstream of the primary swirler outlet, using 76mm radially inward wall injection. This was followed by a dump flow expansion to a 140mm diameter combustor. This provided an expansion shear layer and associated turbulence to mix the second stage fuel with the outlet products from the primary swirl combustion. The second stage fuel burned in the depleted oxygen (∼12%) from the first stage, but still remained a lean combustion zone overall. This design was intended to achieve engine power variation using the second stage fuel. The use of the second stage fuel was shown to reduce the NOx emissions by 50% compared with injecting all of the fuel into the first stage radial swirler. Emission levels of NOx at a first stage swirler equivalence ratio of 0.4 were below 5ppm and at an overall primary zone equivalence ratio of 0.8 with the two stage fuel injection, NOx emissions were about 20ppm. The second stage flame radial distribution of equivalence ratio and emissions was determined by gas analysis. The second stage NOx formation was predicted using CFD with flamelet modelling, with a flamelet strain library computed for 12% oxygen combustion. The mole fraction profile of NOx and combustion temperatures for a range of strain rates in the second stage were predicted. NOx emissions at 0.65 equivalence ratio overall was predicted to be 23ppm at 15% oxygen compared with 16ppm measured. Improved second stage fuel mixing is required to achieve lower NOx emissions and the use of wall turbulators is recommended.

Co-Firing of Kerosene and Biodiesel With Natural Gas in a Low NOx Radial Swirl Combustor

2012 ◽  
Author(s):  
Mohamed A. Altaher ◽  
Hu Li ◽  
Gordon E. Andrews
Keyword(s):  
Natural Gas ◽  
Fuel Injection ◽  
Liquid Fuels ◽  
Inlet Temperature ◽  
Nox Emissions ◽  
Fuel Injector ◽  
Gas Combustion ◽  
Swirl Combustor ◽  
Low Nox Combustion ◽  
Natural Gas Combustion

Co-firing of biodiesel with natural gas, using a low NOx gas turbine combustor was investigated and compared with the equivalent natural gas and kerosene co-firing. The work was carried out at atmospheric pressure with 600K air inlet temperature and used an 8 vane radial swirler. Well mixed natural gas combustion was achieved using radially inward gas fuel injection through the wall of the swirler outlet throat. The biofuel was injected centrally using an eight hole radial fuel injector. This central fuel injector location forms a good pilot flame for natural gas low NOx combustion and was the only fuel injection location that biodiesel combustion could be stabilised. This was because central fuel injection was into the hot recirculating gases on the centreline that is a feature of radial swirl lean low NOX combustion. The biodiesel results were compared with equivalent tests for kerosene as the central injection fuel. Co-firing was investigated with a low level of main natural gas combustion that was held constant and the equivalence ratio was increased using the central injection of biodiesel or kerosene. Operation on kerosene with no acoustic problem was demonstrated up to Ø = 0.95. Three natural gas initial equivalence ratios were investigated with co-firing of liquid fuels, Ø = 0.18, 0.22 and 0.34. A key benefit of operating with hotter premixed combustion with natural gas was that the overall Ø at which stable low CO and HC operation could be achieved with biodiesel was extended to leaner overall Ø. The NOx emissions in this co-firing mode were remarkably low for relatively rich overall mixtures, where conventional single fuel main injection on natural gas gave higher NOx emissions.

Development and Integration of the Dual Fuel Combustion System for the MGT Gas Turbine Family

2021 ◽  
Author(s):  
Bernhard Ćosić ◽  
Frank Reiss ◽  
Marc Blümer ◽  
Christian Frekers ◽  
Franklin Genin ◽  
...  
Keyword(s):  
Gas Turbine ◽  
Distribution System ◽  
Gas Turbines ◽  
Liquid Fuel ◽  
Fuel Injection ◽  
Liquid Fuels ◽  
Dual Fuel ◽  
Gaseous Fuels ◽  
Supply And Distribution ◽  
Industrial Gas Turbines

Abstract Industrial gas turbines like the MGT6000 are often operated as power supply or as mechanical drives. In these applications, liquid fuels like 'Diesel Fuel No.2' can be used either as main fuel or as backup fuel if natural gas is not reliably available. The MAN Gas Turbines (MGT) operate with the Advanced Can Combustion (ACC) system, which is capable of ultra-low NOx emissions for gaseous fuels. This system has been further developed to provide dry dual fuel capability. In the present paper, we describe the design and detailed experimental validation process of the liquid fuel injection, and its integration into the gas turbine package. A central lance with an integrated two-stage nozzle is employed as a liquid pilot stage, enabling ignition and start-up of the engine on liquid fuel only. The pilot stage is continuously operated, whereas the bulk of the liquid fuel is injected through the premixed combustor stage. The premixed stage comprises a set of four decentralized nozzles based on fluidic oscillator atomizers, wherein atomization of the liquid fuel is achieved through self-induced oscillations. We present results illustrating the spray, hydrodynamic, and emission performance of the injectors. Extensive testing of the burner at atmospheric and full load high-pressure conditions has been performed, before verification within full engine tests. We show the design of the fuel supply and distribution system. Finally, we discuss the integration of the dual fuel system into the standard gas turbine package of the MGT6000.

Towards an Innovative Combination of Natural Gas and Liquid Fuel Injection in Spark Ignition Engines

2010 ◽  
Vol 3 (2) ◽  
pp. 196-209 ◽  
Author(s):  
Vivien Delpech ◽  
Jerome Obiols ◽  
Dominique Soleri ◽  
Laurent Mispreuve ◽  
Eric Magere ◽  
...  
Keyword(s):  
Natural Gas ◽  
Liquid Fuel ◽  
Fuel Injection ◽  
Spark Ignition ◽  
Spark Ignition Engines

Development of a Dual-Fuel Injection System for Lean Premixed Industrial Gas Turbines

1996 ◽  
Author(s):  
Luke H. Cowell ◽  
Amjad Rajput ◽  
Douglas C. Rawlins
Keyword(s):  
Natural Gas ◽  
Gas Turbines ◽  
Liquid Fuel ◽  
Fuel Injection ◽  
Premixed Combustion ◽  
Injection System ◽  
Fuel Injection System ◽  
Load Range ◽  
Lean Premixed Combustion ◽  
Lean Premixed

A fuel injection system for industrial gas turbine engines capable of using natural gas and liquid fuel in dry, lean premixed combustion is under development to significantly reduce NOx and CO emissions. The program has resulted in a design capable of operating on DF#2 over the 80 to 100% engine load range meeting the current TA LUFT regulations of 96 ppm (dry, @ 15% O2) NOx and 78 ppm CO. When operating on natural gas the design meets the guaranteed levels of 25 ppm NOx and 50 ppm CO. The design approach is to apply lean premixed combustion technology to liquid fuel. Both injector designs introduce the majority of the diesel fuel via airblast alomization into a premixing passage where fuel vaporization and air-fuel premixing occur. Secondary fuel injection occurs through a pilot fuel passage which operates in a partially premixed mode. Development is completed through injector modeling, flow visualization, combustion rig testing, and engine testing. The prototype design tested in development engine environments has operated with NOx emissions below 65 ppm and 20 ppm CO at full load. This paper includes a detailed discussion of the injector design and qualification testing completed on this development hardware.

Influence of Injection Parameters and Operating Conditions on Ignition and Combustion in Dual-Fuel Engines

2018 ◽  
Vol 140 (10) ◽  
Author(s):  
Marcus Grochowina ◽  
Michael Schiffner ◽  
Simon Tartsch ◽  
Thomas Sattelmayer
Keyword(s):  
Natural Gas ◽  
High Speed ◽  
Measurement Techniques ◽  
Injection Pressure ◽  
Operating Conditions ◽  
Liquid Fuels ◽  
Dual Fuel ◽  
Injection Parameters ◽  
Auto Ignition ◽  
Pilot Fuel

Dual-fuel (DF) engines offer great fuel flexibility since they can either run on gaseous or liquid fuels. In the case of diesel pilot-ignited DF engines, the main source of energy is provided by gaseous fuel, whereas the diesel fuel acts only as an ignition source. Therefore, a proper auto-ignition of the pilot fuel is of utmost importance for combustion in DF engines. However, auto-ignition of the pilot fuel suffers from lower compression temperatures of Miller or Atkinson valve timings. These valve timings are applied to increase efficiency and lower nitrogen oxide (NOx) engine emissions. In order to improve the ignition, it is necessary to understand which parameters influence the ignition in DF engines. For this purpose, experiments were conducted and the influence of parameters, such as injection pressure, pilot fuel quantity, compression temperature, and air–fuel (A/F) equivalence ratio of the homogenous natural gas–air mixture were investigated. The experiments were performed on a periodically chargeable combustion cell using optical high-speed recordings and thermodynamic measurement techniques for pressure and temperature. The study reveals that the quality of the diesel pilot ignition in terms of short ignition delay and a high number of ignited sprays significantly depends on the injection parameters and operating conditions. In most cases, the pilot fuel suffers from too high dilution due to its small quantity and long ignition delays. This results in a small number of ignited sprays and consequently leads to longer combustion durations. Furthermore, the experiments confirm that the natural gas of the background mixture influences the auto-ignition of the diesel pilot oil.

Visualization study of natural gas direct injection combustion

2003 ◽  
Vol 217 (8) ◽  
pp. 667-676 ◽  
Author(s):  
Z Huang ◽  
S Shiga ◽  
T Ueda ◽  
H Nakamura ◽  
T Ishima ◽  
...  
Keyword(s):  
Natural Gas ◽  
High Speed ◽  
Fuel Injection ◽  
Single Injection ◽  
Direct Injection ◽  
Video Camera ◽  
Injection Timing ◽  
Lean Combustion ◽  
High Speed Video Camera ◽  
Wrinkled Flame

A visualization study of natural gas direct injection combustion was carried out by using a high speed video camera. The results show that the distribution of the stratified mixture di ers with the injection mode, with parallel and single injection tending to form a higher degree of mixture stratification than opposed injection. Flame propagates toward the downstream direction in the cases of parallel and single-injection combustion, and flame propagates outward from the centre of the combustion chamber in the case of opposed injection combustion. A characteristic of turbulent combustion with a wrinkled flame front is presented in natural gas direct injection combustion. Super-lean combustion can be realized owing to the formation of an ignitable stratified mixture with the optimum setting of the fuel injection timing.

Comparison of Liquid Fuel/Air Mixing and NOx Emissions for a Tangential Entry Nozzle

1994 ◽  
Author(s):  
Timothy S. Snyder ◽  
Thomas J. Rosfjord ◽  
John B. McVey ◽  
Louis M. Chiappetta
Keyword(s):  
Droplet Size ◽  
Liquid Fuel ◽  
Fuel Injection ◽  
Experimental Program ◽  
Spatial Density ◽  
Main Body ◽  
Initial Droplet ◽  
Combustion Tests ◽  
Initial Droplet Size ◽  
Injection Location

An experimental program was conducted to develop a technique for designing a dry low NOx liquid fuel injection configuration for a tangential entry lean-premixed fuel nozzle. Calculations were performed to predict the effect of liquid fuel injection location, orifice size and spacing, and initial droplet size on the vaporized fuel/air mixture uniformity exiting the highly-swirled premixing nozzle. Combustion tests were conducted at pressures ranging from 10–18 atm, and inlet temperatures ranging from 650–730 K, for the different liquid fuel injection schemes analyzed from the mixing study. Liquid fuel injection configurations that were predicted to give the best fuel/air distribution generated the lowest levels of NOx. The calculated fuel/air uniformity was a weak function of the spatial density of liquid fuel injection sites and the method of injecting the liquid fuel. The injection location and initial droplet size have the greatest impacts on fuel/air uniformity. The analysis indicated that 40 micron diameter droplets mix adequately while larger droplets (80 micron) are centrifuged out of the main body of the flow and produce locally high fuel/air ratios. The NOx levels achieved for the best liquid fuel injection configuration approached those obtained for a well premixed gas fuel configuration using the same tangential entry nozzle.

Results and Experience From Operation and Testing of ALSTOM’s 30 MW GT10C Gas Turbine

2003 ◽  
Author(s):  
Anders Hellberg ◽  
Georg Norden ◽  
Mats Andersson ◽  
Thomas Widgren ◽  
Christer Hjalmarsson ◽  
...  
Keyword(s):  
Natural Gas ◽  
Gas Turbine ◽  
Liquid Fuel ◽  
Engine Performance ◽  
Liquid Fuels ◽  
Critical Parameters ◽  
Test Rig ◽  
Load Range ◽  
Performance And Emissions ◽  
Inlet Conditions

ALSTOM’s new gas turbine, the GT10C, is a 30 MW industrial gas turbine for mechanical drive and power generation, which has been upgraded from the 25 MW GT10B. The thermal efficiency of the new gas turbine is 37.3% at ISO inlet conditions with no losses. The GT10C features a dual-fuel dry low emission gas turbine, with emissions values of 15 ppm NOx on gaseous fuel and 42 ppm NOX on liquid fuel (also dry). The GT10C was first started and operated on load in November 2001 and the test program is ongoing until the fall of 2002. The program covers a complete package test, including gas turbine, auxiliaries and control system, to ensure package availability. For the tests, a new test rig has been built in Finspong, Sweden, for testing on both natural gas and liquid fuels. The tests have been very successful, achieving the product targets, for example below 15 ppm NOx, without combustor pulsations. This paper discusses operation experience from the test rig, where the engine has been tested on both natural gas and liquid fuel over the whole load range. The engine has been equipped with over 1200 measuring points, covering the complete gas turbine. All critical parameters have been carefully verified in the test, such as turbine blade temperature and stresses, combustor temperatures and dynamics and engine performance. Results from the tests and measurements will be discussed in this paper. Performance and emissions will also be evaluated.

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