Development of a Three-Staged Low Emissions Combustor for Industrial Small-Size Gas Turbines

1999 ◽  
Author(s):  
Hiroshi Sato ◽  
Toshiji Amano ◽  
Yoshihiro Iiyama ◽  
Masaaki Mori ◽  
Tsuneaki Nakamura
Keyword(s):  
Gas Turbines ◽  
Gas Flow ◽  
Superior Performance ◽  
Staged Combustion ◽  
Engine Operation ◽  
Fuel Gas ◽  
Low Emission ◽  
Lean Premixed ◽  
Development Temperature ◽  
Combustor Liner

This paper describes the development of an ultra-low emission single-can combustor applicable to 200 kW to 3 MW size natural gas-driven gas turbines for cogeneration systems. The combustor, called a three-staged combustor, was designed by applying the theory of lean premixed staged combustion. The combustor comprises two sets of premixing injector tubes located around the combustor liner downstream of the premixing nozzle equipped with a pilot diffusion nozzle in the center. The combustor controls engine output solely by varying the fuel gas flow without the need for complex variable geometry, such as inlet guide vanes, for combustion airflow control. Reliability, response to load variation and retrofit capability have been greatly improved along with wide low-emission operating range. As the result of the atmospheric rig tests, the three-staged combustor has demonstrated superior performance of 3.5 ppm NOx (O2 = 15%) and 7 ppm CO (O2 = 15%) at full load. Assuming the relationship between NOx emission and pressure and taking into account sequential CO oxidation occurring in the scroll, the performance of the combustor at engine operation is expected to be less than 9 ppm NOx (O2 = 15%) and 50 ppm CO (O2 = 15%) emissions between 25% and 100% engine load. During the development, temperature distribution in the atmospheric combustion was measured in detail to gain comprehensive understanding of the low emissions combustion phenomena. The results of the measurement were compared with the theory of lean premixed staged combustion. Employing the concept of effective mixing ratio, the theory of lean premixed staged combustion has proved to be a powerful method to design a lean premixed staged combustor.

scholarly journals Nitrogen Oxide Reduction by Staged Combustion of Biomass Gas in Gas Turbines — A Modeling Study of the Effect of Mixing

1999 ◽  
Author(s):  
Edgardo G. Coda Zabetta ◽  
Pia T. Kilpinen ◽  
Mikko M. Hupa ◽  
Jukka K. Leppälahti ◽  
C. Krister O. Ståhl ◽  
...  
Keyword(s):  
Gas Turbines ◽  
Nox Reduction ◽  
Plug Flow ◽  
Chemical Kinetic ◽  
Process Variables ◽  
Staged Combustion ◽  
Fuel Gas ◽  
Effective Option ◽  
Fuel Mixing ◽  
Lower Temperature

Detailed chemical kinetic modeling has been used to study the reduction of nitrogen oxides at gas turbine (GT) combustor conditions. A gas from gasification of wood with air has been used as the fuel. An air-staged combustion technique has been adapted. In our previous study a simple plug flow model was used to study the effects of pressure and temperature among others process variables. The air-fuel mixing was assumed perfect and instantaneous. Results showed the NOx reduction mainly affected by both pressure and temperature. The aim of the present work is to establish the effect of air-fuel mixing delay on NOx predictions and to extrapolate indications options for GT. To model the mixing delay, a varying number of air sub-streams are mixed with the fuel gas during different time periods. Alternatively, a combination of a perfectly mixed zone followed by a plug flow zone is illustrated. Results by any air-fuel mixing model show similar affect of process variables on NOx reduction. When a mixing delay is assumed instead of the instantaneous mixing the NOx reduction is enhanced, and only with delayed mixing NOx are affected by CH4. Lower temperature and higher pressure in the GT-combustor can enhance the NOx reduction. Also air staging is an effective option: a 3 stages combustor designed for low mixing speed appear competitive compared to more complicate combustors. The fewer hydrocarbons in the gasification gas the high NOx reduction.

scholarly journals Characterization of Melt Infiltrated SiC/SiC Composite Combustor Liners Using Meso- and Micro-NDE Techniques

2000 ◽  
Author(s):  
W. A. Ellingson ◽  
J. G. Sun ◽  
K. L. More ◽  
R. Hines
Keyword(s):  
Nondestructive Evaluation ◽  
Gas Turbines ◽  
Ceramic Matrix Composite ◽  
Ceramic Matrix ◽  
Test Methods ◽  
End User ◽  
Low Emission ◽  
Material Systems ◽  
Combustor Liner

Melt-infiltrated ceramic matrix composite SiC/SiC material systems are under development for use in combustor liners for low-emission advanced gas turbines. Uncertainty in repeatability of processing methods for these large components (33–76 cm diameter), and hence possible reduced reliability for the end user, requires that appropriate test methods, at both meso- and micro-scale, be used to ensure that the liners are acceptable for use. Nondestructive evaluation (NDE) methods, if demonstrated to reliably detect changes caused by processing, would be of significant benefit to both manufacturer and end user. This paper describes the NDE methods and their applications in detecting a process upset in a melt-infiltrated 33 cm combustor liner and how high-resolution scanning electron microscopy was used to verify the NDE data.

A Fuel Gas System Transient Study for Combined Cycle Plants

2014 ◽  
Author(s):  
Yizhou Yan
Keyword(s):  
Gas Turbines ◽  
Power Plants ◽  
Gas Flow ◽  
Pressure Control ◽  
Combined Cycle ◽  
Transient Model ◽  
Fuel Gas ◽  
Gas System ◽  
Set Up ◽  
Loop Tuning

Fuel gas for many Combined Cycle Power Plants is supplied directly by the gas provider’s regulator station in locations where the gas pipeline pressure is sufficient without further compression. Other locations require one or more onsite compressors to boost the fuel gas pressure. A rising concern is the fuel gas system transient response immediately after a significant reduction in the plant fuel gas consumption. Transient analysis models have been developed for typical fuel gas systems of combined cycle plants to ensure that the system is configured to respond appropriately to unplanned disturbances in fuel gas flow such as when a gas turbine trip occurs. Pressure control (regulator) and booster compressor control loop tuning parameters based on quantitative transient model results could be applied to set up targets for use in specifying and commissioning the fuel gas system. Case studies are presented for typical large combined cycle plants with two gas turbines taking fuel from a common plant header. This is done for designs without or with fuel gas booster compressors.

Specification, Development, and Testing of the FT8-2 Dry Low NOx Control System

1996 ◽  
Vol 118 (3) ◽  
pp. 547-552
Author(s):  
R. C. Bell ◽  
T. W. Prete ◽  
J. T. Stewart
Keyword(s):  
Control System ◽  
Gas Flow ◽  
Closed Loop ◽  
Engine Test ◽  
Lean Burn ◽  
Engine Operation ◽  
Fuel Gas ◽  
Loop Control ◽  
Engine Model ◽  
Nox Control

This paper describes the specification, development, and testing of the FT8-2 Dry Low NOx control system, and how the lean burn process requires an integration of the control system and combustion hardware. The FT8-2 digital fuel control system was developed to achieve the precise multizone fuel metering of both gas and liquid fuels, the calculation of combustor air flow necessary to achieve Dry Low NOx and the traditional governing/limiting control loops necessary for safe, stable engine operation. The system design goals were accomplished by the concurrent development of software-based fuel metering algorithms and fuel metering hardware. The fuel metering hardware utilizes an all-electronic valve positioner, employing a combination of feedback and software to achieve closed-loop control of actual fuel flow. Extensive testing under actual gas flow conditions and closed-loop bench testing using a real time engine model and fuel system model was conducted to prove system operation and develop system transient response prior to installation on the test engine. The setup and results of the flow testing and closed-loop testing are described. The paper describes the control scheme used to apportion the gas fuel between combustion zones and how external conditions such as ambient temperature and fuel gas composition affect the apportionment. The paper concludes with a description of the control system installation in the engine test cell and a review of engine test results.

Specification, Development, and Testing of the FT8-2 Dry Low NOx Control System

1995 ◽  
Author(s):  
Russell C. Bell ◽  
Thomas W. Prete ◽  
Jeffery T. Stewart
Keyword(s):  
Control System ◽  
Gas Flow ◽  
Closed Loop ◽  
Liquid Fuels ◽  
Engine Test ◽  
Engine Operation ◽  
Fuel Gas ◽  
Loop Control ◽  
Engine Model ◽  
Nox Control

This paper describes the specification, development and testing of the FT8-2 Dry Low NOx control system, and how the lean bum process requires an integration of the control system and combustion hardware. The FT8-2 digital fuel control system was developed to achieve the precise multi-zone fuel metering of both gas and liquid fuels, the calculation of combustor air flow necessary to achieve Dry Low NOx and the traditional governing/limiting control loops necessary for safe, stable engine operation. The achievement of the system design goals was accomplished by the concurrent development of software Based fuel metering algorithms and fuel metering hardware. The fuel metering hardware utilizes an all electronic valve positioner, employing a combination of feedback and software to achieve closed loop control of actual fuel flow. Extensive testing under actual gas flow conditions and closed loop bench testing using a real time engine model and fuel system model was conducted to prove system operation and develop system transient response prior to Installation on the test engine. The setup and results of the flow testing and dosed loop testing are described. The paper describes the control scheme used to apportion the gas fuel between combustion zones and how external conditions such as ambient temperature and fuel gas composition effect the apportionment. The paper concludes with a description of the control system installation in the engine test cell and a review of engine test results.

Fuel Switchover at High Load, Integration Into an Engine Operation Concept

2014 ◽  
Author(s):  
Susanne Schell ◽  
Ghislain Singla
Keyword(s):  
Power Output ◽  
Gas Turbines ◽  
High Load ◽  
Combined Cycle ◽  
Fuel Oil ◽  
Load Range ◽  
Engine Operation ◽  
Fuel Gas ◽  
Standard Operation ◽  
Secondary Fuel

The capability to switch online from a main to a back-up fuel is a necessity for dual fuel gas turbines. The switching procedure is itself challenging; fuel gas, fuel oil and supporting systems need to be operated in parallel, with the safe start-up and shut-down of each system having to be ensured. Additionally, the requirements of gas turbine and combined cycle have to be considered; with the target to provide fast reliable fuel switching, without a major effect on the power output. Alstom’s GT26/GT24 High Load Fuel Switchover (HLFSW) fulfils these requirements. HLFSW is a concept which allows switching back and forth between fuel gas and fuel oil in the load range of base load down to 60 % relative GT load. A key feature of the HLFSW is the stable load during the complete duration of the fuel switchover process, ensuring nearly constant power output in combined cycle mode from the moment the fuel switchover is triggered until standard operation is achieved on the secondary fuel. In this paper the integration of the HLFSW into the engine operation concept is presented. It is shown, how the sequential combustion of the Alstom GT26/GT24 is transferred from primary to secondary fuel by sequential fuel switchover. The focus is on how the high load fuel switchover concept is embedded into the gas turbine’s engine operation concept, allowing a smooth transfer between the fuel gas standard operation concept and the fuel oil standard operation concept and vice-versa, resulting in a fuel switchover concept without any significant disturbances to the heat recovery steam generator (HRSG).

Development Approach to the Dry Low Emission Combustion System of MAN Diesel and Turbo Gas Turbines

2014 ◽  
Author(s):  
Holger Huitenga ◽  
Eric R. Norster
Keyword(s):  
High Pressure ◽  
Gas Turbines ◽  
Field Tests ◽  
Test Facility ◽  
Design Parameters ◽  
Combustion System ◽  
Low Emission ◽  
Lean Premixed ◽  
Industrial Gas Turbines ◽  
Gas Pumping

The THM series of industrial gas turbines covers a power range of 6 to 12.5 MW and has been improved and uprated over many years. The majority of turbines installed are still in commercial operation and they are mainly used for compressor drives but also find generator applications. In recent years the constraints of emission legislations for new and existing gas turbines has made a development programme for a dry low emission (DLE) combustion system essential. The combustion system apart from meeting latest emission targets of 75 mg/mN3 NOx and 100 mg/mN3 CO must be suitable for both, new and retrofit engine options and therefore compact for standard enclosure installation. In addition the design should be simple and robust with the same accessibility as the existing standard combustion system. The paper describes the design and development steps to provide a prototype lean premixed DLE combustion system. The basic approach for a simple lean premixed design together with aero-thermodynamic sizing for pressure loss, flow proportions, stability and cooling is described. The initial efforts were directed to a system for the 11 MW THM 1304-11AP machine, with combustor atmospheric testing to verify design parameters and operating limits. The development was continued by subsequent high pressure testing of the prototype, starting with suitable units in the MAN engine test facility, omitting any high pressure rig tests. Field tests were carried out on a compressor drive application on a gas pumping station to prove long term durability. Adaptations of the design are now engine-tested for other THM models, even recuperated ones. Also, the combustor technology and methods developed here provide the basis for the combustors on the new MAN MGT 6100 and 6200 engines [1].

scholarly journals Development of a Dry Ultra Low NOx Double Swirler Staged Gas Turbine Combustor

1996 ◽  
Author(s):  
Hiroshi Sato ◽  
Masaaki Mori
Keyword(s):  
Gas Turbine ◽  
Gas Flow ◽  
Combustion Efficiency ◽  
Nox Emission ◽  
Superior Performance ◽  
Operating Pressure ◽  
Gas Turbine Combustor ◽  
Fuel Gas ◽  
Combustion Tests ◽  
Low Nox Emission

This paper describes the development of an ultra-low NOx gas turbine combustor for cogeneration systems. The combustor, called a double swirler staged combustor, utilizes three-staged premixed combustion for low NOx emission. The unique feature of the combustor is its tertiary premix nozzles located downstream of the double swirler premixing nozzles around the combustor liner. Engine output is controlled by simply varying the fuel gas flow, and therefore employs no complex variable geometries for air flow control. Atmospheric combustion tests have demonstrated the superior performance of the combustor. NOx level is maintained at less than 3 ppm (O2=15%) over the range of engine output between 50% and 100%. Assuming the general relationship that NOx emission is proportional to the square root of operating pressure, the NOx level is estimated at less than 9 ppm (O2=15%) at the actual pressure of 0.91 MPa (abs.). Atmospheric tests have also shown high combustion efficiency; more than 99.9% over the range of engine output between 60% and 100%. Emissions of CO and UHC are maintained at 0 and 1 ppm (O2=15%), respectively, at the full engine load.

Ceramic Stationary Gas Turbine Development

1993 ◽  
Author(s):  
Mark van Roode ◽  
William D. Brentnall ◽  
Paul F. Norton ◽  
Gregory P. Pytanowski
Keyword(s):  
Silicon Carbide ◽  
Silicon Nitride ◽  
Gas Turbine ◽  
Gas Turbines ◽  
Ceramic Materials ◽  
Ceramic Composites ◽  
Department Of Energy ◽  
Engine Operation ◽  
Component Design ◽  
Combustor Liner

A program has been initiated under the sponsorship of the Department of Energy (DOE), Office of Industrial Technology, to improve the performance of stationary gas turbines in cogeneration through the selective replacement of metallic hot section parts with uncooled ceramic components. It is envisioned that the successful demonstration of ceramic gas turbine technology, and the systematic incorporation of ceramics in existing and future gas turbines will enable more efficient engine operation, resulting in significant fuel savings, increased output power, and reduced emissions. The program which started in September, 1992, takes an engine of the Solar Centaur family of industrial gas turbines, and modifies the design of the hot section to accept ceramic first stage blades and first stage nozzles, and a ceramic combustor liner. The ceramic materials selected for the blade are silicon nitride, for the nozzle silicon nitride and silicon carbide, and for the combustor liner silicon carbide as well as two continuous fiber reinforced ceramic composites, one with a silicon carbide matrix and another with an oxide matrix. This paper outlines the approach, conceptual component design, and materials selection for the program.

The Design, Selection, and Application of Oil-Injected Screw Compressors for Fuel Gas Service

1995 ◽  
Vol 117 (1) ◽  
pp. 81-87
Author(s):  
S. Tsutsumi ◽  
J. Boone
Keyword(s):  
Gas Turbines ◽  
Gas Flow ◽  
High Reliability ◽  
Slide Valve ◽  
Screw Compressor ◽  
Gas Temperature ◽  
Fuel Gas ◽  
Discharge Gas ◽  
Design Selection ◽  
Environmentally Sound

Fuel gas compressors installed in cogeneration systems must be highly reliable and efficient machines, like the other main components, such as gas turbines, gas engines, etc. In the range of gas flow rate and pressure conditions generally required for such systems, the oil-injected screw compressor is often the most suitable compressor type for these requirements. Advantages of oil injected screw compressors are: improved compression efficiency; low discharge gas temperature; high reliability; simple mechanical construction; which all result from injection of lubricant into the compressor. Injected lubricant is discharged together with compressed gas on the high-pressure side but the oil is separated by a fine oil separation system down to a level that causes no problems for the downstream combustion equipment. The oil-injected screw compressor is equipped with an integral stepless capacity control by means of a slide valve, which makes part-load operation possible with reduced power consumption and improves overall system efficiency. As cogeneration systems, which are energy efficient and environmentally sound, are now increasing in number, so oil-injected screw compressors are expected to be used more widely.

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