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

Author(s):  
Bernhard Ćosić ◽  
Frank Reiss ◽  
Marc Blümer ◽  
Christian Frekers ◽  
Franklin Genin ◽  
...  

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.

Author(s):  
Hu Li ◽  
Mohamed Altaher ◽  
Gordon E. Andrews

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.


2021 ◽  
Author(s):  
Bernhard Ćosić ◽  
Frank Reiß ◽  
Marc Blümer ◽  
Christian Frekers ◽  
Franklin Genin ◽  
...  

Abstract Industrial gas turbines like the MGT6000 are often operated as power supply or as mechanical drives for pumps and compressors at remote locations on islands and in deserts. Moreover, small gas turbines are used in CHP applications with a high need for availability. 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 already capable of ultra-low NOx emissions for a variety of gaseous fuels. This system has been further developed to provide dry dual fuel capability to the MGT family. 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, without the need for any additional atomizing air. The pilot stage is continuously operated to support further the flame stabilization across the load range, whereas the bulk of the liquid fuel is injected through the premixed combustor stage. The premixed stage comprises a set of four decentralized nozzles placed at the exit of the main air swirler. These premixed nozzles are based on fluidic oscillator atomizers, wherein a rapid and effective atomization of the liquid fuel is achieved through self-induced oscillations of the liquid fuel stream. We present results of numerical and experimental investigations performed in the course of the development process illustrating the spray, hydrodynamic, and thermal performance of the pilot injectors. Extensive testing of the burner at atmospheric and full load high-pressure conditions has been performed, before verification of the whole combustion system within full engine tests. The burner shows excellent emission performance (NOx, CO, UHC, soot) without additional water injection, while maintaining the overall natural gas performance. Soot and particle emissions, quantified via several methods, are well below legal restrictions. Furthermore, when not in liquid fuel operation, a continuous purge of the injectors based on compressor outlet (p2) air has been laid out. Generic atmospheric coking tests were conducted before verifying the purge system in full engine tests. Thereby we completely avoid the need for an additional high-pressure auxiliary compressor or demineralized water. We show the design of the fuel supply and distribution system. We designed it to allow for rapid fuel switchovers from gaseous fuel to liquid fuel, and for sharp load jumps. Finally, we discuss the integration of the dual fuel system into the standard gas turbine package of the MGT6000 in detail.


Author(s):  
Y. Wang ◽  
L. Reh ◽  
D. Pennell ◽  
D. Winkler ◽  
K. Döbbeling

Stationary gas turbines for power generation are increasingly being equipped with low emission burners. By applying lean premixed combustion techniques for gaseous fuels both NOx and CO emissions can be reduced to extremely low levels (NOx emissions <25vppm, CO emissions <10vppm). Likewise, if analogous premix techniques can be applied to liquid fuels (diesel oil, Oil No.2, etc.) in gas-fired burners, similar low level emissions when burning oils are possible. For gas turbines which operate with liquid fuel or in dual fuel operation, VPL (Vaporised Premixed Lean)-combustion is essential for obtaining minimal NOx-emissions. An option is to vaporise the liquid fuel in a separate fuel vaporiser and subsequently supply the fuel vapour to the natural gas fuel injection system; this has not been investigated for gas turbine combustion in the past. This paper presents experimental results of atmospheric and high-pressure combustion tests using research premix burners running on vaporised liquid fuel. The following processes were investigated: • evaporation and partial decomposition of the liquid fuel (Oil No.2); • utilisation of low pressure exhaust gases to externally heat the high pressure fuel vaporiser; • operation of ABB premix-burners (EV burners) with vaporised Oil No.2; • combustion characteristics at pressures up to 25bar. Atmospheric VPL-combustion tests using Oil No.2 in ABB EV-burners under simulated gas turbine conditions have successfully produced emissions of NOx below 20vppm and of CO below 10vppm (corrected to 15% O2). 5vppm of these NOx values result from fuel bound nitrogen. Little dependence of these emissions on combustion pressure bas been observed. The techniques employed also ensured combustion with a stable non luminous (blue) flame during transition from gaseous to vaporised fuel. Additionally, no soot accumulation was detectable during combustion.


Author(s):  
W. S. Y. Hung ◽  
J. G. Meier

This paper describes the successful development and application of industrial gas turbines using alternate gaseous fuels. These fuels include liquid petroleum gas, medium-Btu fuels derived from biodegradation of organic matters found in sanitary landfills and liquid sewage, and ultra-low Btu fuels from oilfield fireflood operations. The analyses, mathematical modelling and rig verification performed in the development are discussed. The effects of burning these alternate fuels on the gas turbine and its combustion system are compared to those of using standard natural gas fuel. Gas turbine development required to use other alternative gaseous fuels is also assessed.


Author(s):  
Aristotelis Komodromos ◽  
George Moniatis ◽  
Frixos Kontopoulos ◽  
George Zaimis ◽  
Matthieu Vierling ◽  
...  

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.


1986 ◽  
Vol 108 (1) ◽  
pp. 182-190 ◽  
Author(s):  
J. G. Meier ◽  
W. S. Y. Hung ◽  
V. M. Sood

This paper describes the successful development and application of industrial gas turbines using medium-Btu gaseous fuels, including those derived from biodegradation of organic matters found in sanitary landfills and liquid sewage. The effects on the gas turbine and its combustion system of burning these alternate fuels compared to burning high-Btu fuels, along with the gas turbine development required to use alternate fuels from the point of view of combustion process, control system, gas turbine durability, maintainability and safety, are discussed.


Author(s):  
T. J. Rosfjord ◽  
J. B. McVey ◽  
R. A. Sederquist ◽  
D. F. Schultz

Gaseous fuels produced from coal resources have been considered for use in industrial gas turbines. Such fuels generally have heating values much lower than the typical gaseous fuel, natural gas; the low heating value could result in unstable or inefficient combustion. Additionally, coal gas fuels may contain ammonia which if oxidized in an uncontrolled manner could result in unacceptable NOx exhaust emission levels. Previous investigations have indicated that staged, rich-lean combustion represents a desirable approach to achieve stable, efficient, low NOx emission operation for coal-derived liquid fuels containing up to 0.8-wt pct nitrogen. An experimental program has been conducted to determine whether this fuel tolerance can be extended to include coal-derived gaseous fuels. The results of tests with three nitrogen-free fuels having heating values of 100, 250, and 350 Btu/scf and a 250 Btu/scf heating value doped to contain 0.7 pct ammonia are presented.


Author(s):  
Olle Lindman ◽  
Mats Andersson ◽  
Magnus Persson ◽  
Erik Munktell

This paper describes the latest results from the development of a liquid fuel solution for the 4th generation DLE system for Siemens medium size gas turbines. Gaseous fuels are the dominating fuels for industrial gas turbines. However, many customers need to be able to run on liquid fuel as backup. The demand for dry low NOx emissions when operating on liquid fuel is increasing. The aim for the 4th generation DLE system incorporated in the recently released SGT-750 [1] is to have emission levels well below market demands on both gas and liquid fuel. This paper will highlight the technical challenges when adding liquid fuel operation to a combustion system optimized for gas operation. The stand-alone spray characteristics for a liquid fuel nozzle is quite easy to predict, but the final combustion performance in a hot air cross flow environment is all but easy to predict by numerical simulations or cold flow tests [2]. Due to the complexity of the challenge, the development program focused on a selection of concepts for which fuel/air mixing calculations were made. The investigation was completed by testing in a full scale, single burner high pressure combustion test rig.


Author(s):  
Christian Steinbach ◽  
Thomas Ruck ◽  
Jonathan Lloyd ◽  
Peter Jansohn ◽  
Klaus Döbbeling ◽  
...  

A dual fuel burner has been developed to meet stringent NOx goals without the use of water or steam injection. This combustion system is based on the proven ABB EV burner dry low NOx technology and uses the same type of aerodynamic vortex breakdown flame stabilization. A more advanced aerodynamic design improves the quality of the fuel air mixture for both gaseous and liquid fuels. The design of the liquid fuel injection and the fuel-air-mixture preparation is described in this paper. Fuel air mixture homogeneity was improved with the help of experimental and numerical tools. This way an optimization in fuel atomizer design was possible. Distinct differences in fuel distribution were observed for different designs of pressure atomizers. Combustion tests of the burner were performed at pressures up to 20 bars. The NOx levels measured under gas turbine full load conditions are <25 vppm using oil no. 2 and <10 vppm using natural gas. These results highlight the potential for achieving similar combustion low emission performance for gaseous and liquid fuels near perfect lean premix conditions. Operating parameters and test results at part load conditions are discussed as well in this paper. The wide operating range of the burner in the full premix mode restricts the need for pilot application or burner staging to low load (<50 %) conditions. This allows for low emissions on NOx, CO and UHC in the entire load range.


Author(s):  
H. S. Alkabie ◽  
G. E. Andrews

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.


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