scholarly journals Low NOx Premixed Combustion of MBTU Fuels Using the ABB Double Cone Burner (EV Burner)

1994 ◽  
Author(s):  
K. Döbbeling ◽  
H. P. Knöpfel ◽  
W. Polifke ◽  
D. Winkler ◽  
C. Steinbach ◽  
...  
Keyword(s):  
Gas Turbine ◽  
High Speed ◽  
Coal Gasification ◽  
Fuel Injection ◽  
Double Cone ◽  
Premixed Combustion ◽  
Injection Method ◽  
Wide Range ◽  
Ev Burner ◽  
Combustion Technique

A novel combustion technique, based on the Double Cone Burner, has been developed and tested. NOx emissions down to very low levels are reached without the usual strong dilution of the fuel for MBtu syngases from oxygen blown gasification of coal or residual oil. A limited amount of dilution is necessary in order to prevent ignition during the mixing of fuel and combustion air. The relevant properties of the fuel are reviewed in relation to the goal of achieving premixed combustion. The basic considerations lead to a fuel injection strategy which is completely different from that for natural gas. A high speed premixing system is necessary due to the very short chemical reaction times of MBtu fuel. Fuel must be prevented from forming ignitable mixtures inside the burner for reliability reasons. A suitable fuel injection method, which can be easily added to the ABB double cone burner, is described. In common with the design of the standard EV burner, the MBtu EV burner with this fuel injection method is inherently safe against flashback. Three dimensional flow field and combustion modelling is used to investigate the mixing patterns and the location of the reaction front. Two burner test facilities, one operating at ambient and the other at full gas turbine pressure, have been used for the evaluation of different burner designs. The full pressure tests were carried out with the original gas turbine burner size and geometry. Combing the presented numerical predictive capabilities and the experimental test facilities, burner performance can be reliably assessed for a wide range of MBtu and LBtu fuels (residue oil gasification, waste gasification, coal gasification etc.). The atmospheric tests of the burner show NOx values below 2 ppm at an equivalence ratio equal to full load gas turbine operation. The NOx increase with pressure was found to be very high. Nevertheless, NOx levels of 25 vppmd (@ 15% O2) have been measured at full gas turbine pressure. Implemented into ABB’s recently introduced gas turbine GT13E2 the new combustion technique will allow a more straightforward IGCC plant configuration without air extraction from the gas turbine to be used.

Low-Nox Premixed Combustion of MBtu Fuels Using the ABB Double Cone Burner (EV Burner)

1996 ◽  
Vol 118 (1) ◽  
pp. 46-53 ◽  
Author(s):  
K. Do¨bbeling ◽  
H. P. Kno¨pfel ◽  
W. Polifke ◽  
D. Winkler ◽  
C. Steinbach ◽  
...  
Keyword(s):  
Gas Turbine ◽  
High Speed ◽  
Coal Gasification ◽  
Fuel Injection ◽  
Double Cone ◽  
Premixed Combustion ◽  
Injection Method ◽  
Wide Range ◽  
Ev Burner ◽  
Combustion Technique

A novel combustion technique, based on the Double Cone Burner, has been developed and tested. NOx emissions down to very low levels are reached without the usual strong dilution of the fuel for MBtu syngases from oxygen-blown gasification of coal or residual oil. A limited amount of dilution is necessary in order to prevent ignition during the mixing of fuel and combustion air. The relevant properties of the fuel are reviewed in relation to the goal of achieving premixed combustion. The basic considerations lead to a fuel injection strategy completely different from that for natural gas. A high-speed premixing system is necessary due to the very short chemical reaction times of MBtu fuel. Fuel must be prevented from forming ignitable mixtures inside the burner for reliability reasons. A suitable fuel injection method, which can be easily added to the ABB double cone burner, is described. In common with the design of the standard EV burner, the MBtu EV burner with this fuel injection method is inherently safe against flashback. Three-dimensional flow field and combustion modeling is used to investigate the mixing patterns and the location of the reaction front. Two burner test facilities, one operating at ambient and the other at full gas turbine pressure, have been used for the evaluation of different burner designs. The full-pressure tests were carried out with the original gas turbine burner size and geometry. Combining the presented numerical predictive capabilities and the experimental test facilities, burner performance can be reliably assessed for a wide range of MBtu and LBtu fuels (residue oil gasification, waste gasification, coal gasification, etc.). The atmospheric tests of the burner show NOx values below 2 ppm at an equivalence ratio equal to full-load gas turbine operation. The NOx increase with pressure was found to be very high. Nevertheless, NOx levels of 25 vppmd (@ 15 percent O2) have been measured at full gas turbine pressure. Implemented into ABB’s recently introduced gas turbine GT13E2, the new combustion technique will allow a more straightforward IGCC plant configuration without air extraction from the gas turbine to be used.

Boundary Layer Flashback Limits of Hydrogen-Methane-Air Flames in a Generic Swirl Burner at Gas Turbine Relevant Conditions

2020 ◽  
Author(s):  
Dominik Ebi ◽  
Peter Jansohn
Keyword(s):  
Boundary Layer ◽  
Gas Turbine ◽  
Wall Temperature ◽  
Gas Turbines ◽  
High Speed ◽  
Cooling System ◽  
Atmospheric Conditions ◽  
Preheat Temperature ◽  
Swirl Burner ◽  
Wide Range

Abstract Operating stationary gas turbines on hydrogen-rich fuels offers a pathway to significantly reduce greenhouse gas emissions in the power generation sector. A key challenge in the design of lean-premixed burners, which are flexible in terms of the amount of hydrogen in the fuel across a wide range and still adhere to the required emissions levels, is to prevent flame flashback. However, systematic investigations on flashback at gas turbine relevant conditions to support combustor development are sparse. The current work addresses the need for an improved understanding with an experimental study on boundary layer flashback in a generic swirl burner up to 7.5 bar and 300° C preheat temperature. Methane-hydrogen-air flames with 50 to 85% hydrogen by volume were investigated. High-speed imaging was applied to reveal the flame propagation pathway during flashback events. Flashback limits are reported in terms of the equivalence ratio for a given pressure, preheat temperature, bulk flow velocity and hydrogen content. The wall temperature of the center body along which the flame propagated during flashback events has been controlled by an oil heating/cooling system. This way, the effect any of the control parameters, e.g. pressure, had on the flashback limit was de-coupled from the otherwise inherently associated change in heat load on the wall and thus change in wall temperature. The results show that the preheat temperature has a weaker effect on the flashback propensity than expected. Increasing the pressure from atmospheric conditions to 2.5 bar strongly increases the flashback risk, but hardly affects the flashback limit beyond 2.5 bar.

GT36 Turbine Aero-Thermal Development and Validation

2017 ◽  
Author(s):  
S. Naik ◽  
J. Krueckels ◽  
M. Henze ◽  
W. Hofmann ◽  
M. Schnieder
Keyword(s):  
Gas Turbine ◽  
High Speed ◽  
Pressure Sensors ◽  
Thermal Design ◽  
Local Pressure ◽  
Cooling Systems ◽  
Wide Range ◽  
Turbine Vanes ◽  
Thermal Development ◽  
Development And Validation

This paper describes the aero-thermal development and validation of the GT36 heavy duty gas turbine. The turbine which has evolved from the existing and proven GT26 design, consists of an optimised annulus flow path, higher lift aerofoil profiles, optimised aerodynamic matching between the turbine stages and new and improved cooling systems of the turbine vanes and blades. A major design feature of the turbine has been to control and reduce the aerodynamic losses, associated with the aerofoil profiles, trailing edges, blade tips, endwalls and coolant ejection. The advantages of these design changes to the overall gas turbine efficiency have been verified via extensive experimental testing in high-speed cascade test rigs and via the utilisation of high fidelity multi-row computational fluid dynamics design systems. The thermal design and cooling systems of the turbine vanes, blades have also been improved and optimised. For the first stage vane and blade aerofoils and platforms, multi-row film cooling with new and optimised diffuser cooling holes have been implemented and validated in high speed linear cascades. Additionally, the internal cooling design features of all the blades and vanes were also improved and optimised, which allowed for more homogenous metal temperatures distributions on the aerofoils. The verification and validation of the internal thermal designs of all the turbine components has been confirmed via extensive testing in dedicated Perspex models, where measurements were conducted for local pressure losses, overall flow distributions and local heat transfer coefficients. The turbine is currently being tested and undergoing validation in the GT36 Test Power Plant in Birr, Switzerland. The gas turbine is heavily instrumented with a wide range of validation instrumentation including thermocouples, pressure sensors, strain gauges and five-hole probes. In addition to performance mapping and operational validation, a dedicated thermal paint validation test will also be performed.

scholarly journals Experimental and Computational Study of Trapped Vortex Combustor Sector Rig with High-Speed Diffuser Flow

2001 ◽  
Vol 7 (6) ◽  
pp. 375-385 ◽  
Author(s):  
R. C. Hendricks ◽  
D. T. Shouse ◽  
W. M. Roquemore ◽  
D. L. Burrus ◽  
B. S. Duncan ◽  
...  
Keyword(s):  
Gas Turbine ◽  
High Speed ◽  
Fuel Injection ◽  
Computational Study ◽  
Combustion Efficiency ◽  
Flame Stabilization ◽  
Performance Data ◽  
Pollutant Emissions ◽  
Choked Flow ◽  
Trapped Vortex

The Trapped Vortex Combustor (TVC) potentially offers numerous operational advantages over current production gas turbine engine combustors. These include lower weight, lower pollutant emissions, effective flame stabilization, high combustion efficiency, excellent high altitude relight capability, and operation in the lean burn or RQL modes of combustion. The present work describes the operational principles of the TVC, and extends diffuser velocities toward choked flow and provides system performance data. Performance data include EINOx results for various fuel-air ratios and combustor residence times, combustion efficiency as a function of combustor residence time, and combustor lean blow-out (LBO) performance. Computational fluid dynamics (CFD) simulations using liquid spray droplet evaporation and combustion modeling are performed and related to flow structures observed in photographs of the combustor. The CFD results are used to understand the aerodynamics and combustion features under different fueling conditions. Performance data acquired to date are favorable compared to conventional gas turbine combustors. Further testing over a wider range of fuel-air ratios, fuel flow splits, and pressure ratios is in progress to explore the TVC performance. In addition, alternate configurations for the upstream pressure feed, including bi-pass diffusion schemes, as well as variations on the fuel injection patterns, are currently in test and evaluation phases.

System Evaluation and LBTU Fuel Combustion Studies for IGCC Power Generation

1995 ◽  
Vol 117 (4) ◽  
pp. 673-677 ◽  
Author(s):  
C. S. Cook ◽  
J. C. Corman ◽  
D. M. Todd
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Coal Gasification ◽  
Flame Temperature ◽  
Combined Cycle ◽  
Gas Turbine Combustor ◽  
Gas Cleaning ◽  
Wide Range ◽  
Cycle Systems ◽  
Combined Cycles

The integration of gas turbines and combined cycle systems with advances in coal gasification and gas stream cleanup systems will result in economically viable IGCC systems. Optimization of IGCC systems for both emission levels and cost of electricity is critical to achieving this goal. A technical issue is the ability to use a wide range of coal and petroleum-based fuel gases in conventional gas turbine combustor hardware. In order to characterize the acceptability of these syngases for gas turbines, combustion studies were conducted with simulated coal gases using full-scale advanced gas turbine (7F) combustor components. It was found that NOx emissions could be correlated as a simple function of stoichiometric flame temperature for a wide range of heating values while CO emissions were shown to depend primarily on the H2 content of the fuel below heating values of 130 Btu/scf (5125 kJ/NM3) and for H2/CO ratios less than unity. The test program further demonstrated the capability of advanced can-annular combustion systems to burn fuels from air-blown gasifiers with fuel lower heating values as low as 90 Btu/scf (3548 kJ/NM3) at 2300°F (1260°C) firing temperature. In support of ongoing economic studies, numerous IGCC system evaluations have been conducted incorporating a majority of the commercial or near-commercial coal gasification systems coupled with “F” series gas turbine combined cycles. Both oxygen and air-blown configurations have been studied, in some cases with high and low-temperature gas cleaning systems. It has been shown that system studies must start with the characteristics and limitations of the gas turbine if output and operating economics are to be optimized throughout the range of ambient operating temperature and load variation.

scholarly journals Conversion of Liquid to Gaseous Fuel for Prevaporised Premixed Combustion in Gas Turbines

1997 ◽  
Author(s):  
Y. Wang ◽  
L. Reh ◽  
D. Pennell ◽  
D. Winkler ◽  
K. Döbbeling
Keyword(s):  
High Pressure ◽  
Gas Turbine ◽  
Gas Turbines ◽  
Liquid Fuel ◽  
Fuel Injection ◽  
Premixed Combustion ◽  
Fuel Oil ◽  
Injection System ◽  
Nox Emissions ◽  
Combustion Tests

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.

A New Hybrid Air Blast Nozzle for Advanced Gas Turbine Combustors

2000 ◽  
Author(s):  
Adel Mansour ◽  
Michael Benjamin ◽  
Erlendur Steinthorsson
Keyword(s):  
Gas Turbine ◽  
Thermal Management ◽  
Fuel Injection ◽  
Injection System ◽  
Operating Pressure ◽  
Air Blast ◽  
Pressure Drops ◽  
Fuel Delivery ◽  
Wide Range ◽  
Atomization Performance

The push towards higher specific fuel consumption and smaller, lighter packaging for aerospace gas turbine engines has resulted in large increases in engine operating pressure and temperature. This is a trend that is expected to continue, and as a result, thermal management of the hot engine section including the fuel nozzle, combustor, and turbine has emerged as a critical technology area requiring further development. For the fuel injection system, nozzle thermal management, turndown ratio, and atomization performance while maintaining correct combustor aerodynamics are the most important performance features that necessitate optimization. Significant advances in fuel injection concepts are required to meet the increasingly demanding combustor requirements. Complex heat-shielded designs are often required to reduce nozzle wetted-wall temperatures and prevent the formation of carbonaceous deposits within the fuel delivery passages. To support the development of advanced combustors and address these increasing performance demands, Parker has developed a new Hybrid Air Blast nozzle. Advanced analytical and experimental design tools were applied to reduce the cut-and-try approach previously used in nozzle development. The developed hybrid air blast design achieved excellent atomization performance over a wide range of fuel flow rates and air pressure drops. Thermal analysis of the nozzle showed that the wetted wall temperatures were reduced considerably when compared to previous designs operating at the same conditions. Eight-port circumferential spray patternation results were outstanding with the patternation factor at various values of liquid flow rate ranging between 0.12 and 0.18. This patternation factor is a significant improvement over those of current state-of-the-art injectors that are typically of the order of 0.25.

EVALUATION METHOD OF GAS TURBINE BLADES COVERING INTEGRITY BY IR CAMERA

2006 ◽  
Vol 20 (25n27) ◽  
pp. 4329-4334 ◽  
Author(s):  
DONG-JO YANG ◽  
CHOUL-JUN CHOI ◽  
JAE-YEOL KIM
Keyword(s):  
Gas Turbine ◽  
Infrared Thermography ◽  
Turbine Blade ◽  
High Speed ◽  
Evaluation Method ◽  
Coating Layer ◽  
Turbine Blades ◽  
Gas Turbine Blade ◽  
Ir Camera ◽  
Wide Range

Key parts of the main equipment in a gas turbine may likely be damaged due to operation under high temperature, high pressure, high-speed rotation, etc. Accordingly, the cost for maintenance increases and the damaged parts may cause generation to stop. The surface of a blade is thermal-sprayed, using powder with main compositions such as Ni , Cr , Al , etc, in order to inhibit hot oxidation. Conventional regular maintenance of the coating layer of a blade is made by FPI (Fluorescent Penetrant Inspection) and MTP (Magnetic Particle Testing). Such methods, however, are complicated and take a long time and also require high cost. In this study, defect diagnostics were tested on the coating layer of an industrial gas turbine blade, using an infrared thermography camera. Since the infrared thermography method can check a temperature distribution by means of non-contact on a wide range of areas, it can advantageously save expense and time as compared to conventional test methods. For the infrared thermography method, however, thermo-load must be applied onto a tested specimen and it is difficult to quantify the measured data. To solve the problems, this paper includes description about producing a specimen of a gas turbine blade (bucket), applying thermo-load onto the produced specimen, photographing thermography images by an infrared thermography camera, analyzing the thermography images, and pre-testing to analyze defects on the coating layer of the gas turbine blade.

scholarly journals Effect of Air Extraction for Cooling and/or Gasification on Combustor Flow Uniformity

1998 ◽  
Author(s):  
T. Wang ◽  
J. S. Kapat ◽  
W. R. Ryan ◽  
I. S. Diakunchak ◽  
R. L. Bannister
Keyword(s):  
Flow Field ◽  
Gas Turbine ◽  
Gas Turbines ◽  
Coal Gasification ◽  
Field Experiments ◽  
Fuel Injection ◽  
Flow Distribution ◽  
Flow Uniformity ◽  
Complex Flow ◽  
Local Flow

Reducing emissions is an important issue facing gas turbine manufacturers. Almost all of the previous and current research and development for reducing emissions has focused, however, on flow, heat transfer, and combustion behavior in the combustors or on the uniformity of fuel injection without placing strong emphasis on the flow uniformity entering the combustors. In response to the incomplete understanding of the combustor’s inlet air flow field, experiments were conducted in a 48% scale, 360° model of the diffuser-combustor section of an industrial gas turbine. In addition, the effect of air extraction for cooling or gasification on the flow distributions at the combustors’ inlets was also investigated. Three different air extraction rates were studied: 0% (baseline), 5% (airfoil cooling), and 20% (for coal gasification). The flow uniformity was investigated for two aspects: (a) global uniformity, which compared the mass flow rates of combustors at different locations relative to the extraction port, and (b) local uniformity, which examined the circumferential flow distribution into each combustor. The results indicate that even for the baseline case with no air extraction there was an inherent local flow aonuniformity of 10 ∼ 20% at the inlet of each combustor due to the complex flow field in the dump diffuser and the blockage effect of the cross-flame tube. More flow was seen in the portion further away from the gas turbine center axis. The effect of 5% air extraction was small. Twenty-percent air extraction introduced approximately 35% global flow asymmetry diametrically across the dump diffuser. The effect of air extraction on the combustor’s local flow uniformity varied with the distances between the extraction port and each individual combustor. Longer top hats were installed with the initial intention of increasing flow mixing prior to entering the combustor. However, the results indicated that longer top hats do not improve the flow uniformity; sometimes, adverse effects can be seen. Although a specific geometry was selected for this study, the results provide sufficient generality to benefit other industrial gas turbines.

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.

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