Investigation of Hydrogen Enriched Methane Flame in a Dry Low Emission Industrial Prototype Burner at Atmospheric Pressure Conditions

2017 ◽  
Author(s):  
Arman Ahamed Subash ◽  
Robert Collin ◽  
Marcus Aldén ◽  
Atanu Kundu ◽  
Jens Klingmann
Keyword(s):  
Atmospheric Pressure ◽  
Laminar Flame ◽  
Burning Velocity ◽  
Flame Stabilization ◽  
Oh Radicals ◽  
Burner Exit ◽  
Low Emission ◽  
Planar Laser ◽  
Pilot Fuel ◽  
Fuel Mixtures

Experiments were performed on a prototype 4th generation DLE (dry low emission) burner under atmospheric pressure conditions to investigate the effects of hydrogen (H2) enrichment on methane (CH4) flames. The burner assembly was designed to have three concentrically arranged premixed sections: an outer Main section, an intermediate section (Pilot) and a central pilot body termed the RPL (Rich-Pilot-Lean) section. The Planar laser-induced fluorescence (PLIF) of OH radicals together with flame chemiluminescence imaging were employed for studying the local flame characteristics so as to be able to investigate the turbulence-flame interactions and the location of the reaction zone at the burner exit. Flames were investigated for three different fuel mixtures having hydrogen (H2)/methane (CH4) in vol. % concentration of 0/100, 25/75 and 50/50. The results show that the characteristics of the flames are clearly affected by the addition of hydrogen and the effects are expected due to the faster reaction rate, higher diffusivity and higher laminar burning velocity of H2. Enriching the flame with H2 at a constant global phi (ϕ) is found to shorten the total extension of the flame due to the higher laminar flame speed. The OH signal distribution becomes thicker and more pronounced due to the higher production of OH radicals, and the flame stabilization zone that is produced after the burner throat, moves further downstream. At a constant global ϕ in altering the RPL and the Pilot ϕ, similar changes for both 0/100 and 25/75 (in vol. %) of the H2/CH4 fuel mixtures can be observed. At a rich RPL ϕ, the secondary RPL flame contributes to the main flame and to determining the flame stabilization position. The flame stabilization zone located after the burner throat moves further downstream with an increase in the RPL ϕ. When the PFR (Pilot fuel ratio) increases, the extension of the flame shortens and the flame stabilization zone moves upstream. Combustion emissions were also determined so as to observe the effects of the H2 enrichment on the NOX level.

Laser-Based Investigation on a Dry Low Emission Industrial Prototype Burner at Atmospheric Pressure Conditions

2016 ◽  
Author(s):  
Arman Ahamed Subash ◽  
Robert Collin ◽  
Marcus Aldén ◽  
Atanu Kundu ◽  
Jens Klingmann
Keyword(s):  
Atmospheric Pressure ◽  
Combustion Products ◽  
Flame Stabilization ◽  
Operating Conditions ◽  
Oh Radicals ◽  
Burner Exit ◽  
Planar Laser ◽  
Pilot Fuel ◽  
Intermediate Section ◽  
Primary Combustion Products

Experiments were performed at atmospheric pressure conditions on the prototype 4th generation DLE burner. The combustion changes that occur for alteration of the operating conditions by changing the equivalence ratios (ϕ) for CH4 as fuel at different sections of the burner, were optically investigated. The burner assembly has three concentrically arranged premixed burner sections: an outer Main section, an intermediate section (Pilot) and a central pilot body or pre-chamber combustor, called RPL (Rich-Pilot-Lean) section. All sections are facilitated to vary equivalence ratios to achieve optimal combustion. Planar laser-induced fluorescence (PLIF) of OH radicals and flame chemiluminescence imaging were applied to study the local flame characteristics in order to investigate turbulence-flame interaction and formation of reaction zone at the burner exit. The results show that the position and shape of the flame are clearly affected by the variation of equivalence ratios at different sections of the burner. During the experiments, first the RPL, then the Pilot and the Main flame were added in a step wise manner keeping constant the total air flow for the global ϕ = 0.5 in order to understand the flame contributions from the different combustion sections. It is observed that for the RPL fuel lean conditions, the primary combustion starts and reaches completion before exiting the burner throat while for rich conditions, the residual fuel escapes out through the RPL exit with primary combustion products and starts secondary combustion along with the Pilot and Main combustion. At the global ϕ = 0.5, for changing the RPL ϕ from lean to rich conditions, the flame stabilization region moves downstream of the burner exit and the flame front fluctuation along inner shear layer increases. For increasing the global ϕ and increasing the Pilot fuel ratio (PFR) without changing the RPL and the global ϕ, the total extension of the flame becomes shorter and the flame stabilization region moves upstream.

Experimental Investigation of the Influence of Burner Geometry on Flame Characteristics at a Dry Low Emission Industrial Prototype Burner at Atmospheric Pressure Conditions

2017 ◽  
Author(s):  
Arman Ahamed Subash ◽  
Robert Collin ◽  
Marcus Aldén ◽  
Atanu Kundu ◽  
Jens Klingmann
Keyword(s):  
Atmospheric Pressure ◽  
Recirculation Zone ◽  
Flame Stabilization ◽  
Operating Conditions ◽  
Oh Radicals ◽  
Flow Area ◽  
Burner Exit ◽  
Low Emission ◽  
Planar Laser ◽  
Conical Section

Laser based investigations were performed on a prototype 4th generation DLE (dry low emission) burner under atmospheric pressure conditions to study the effects of changing burner geometry on the flame. In a full burner configuration, a divergent conical section termed the Quarl is located after the burner exit for expanding the flow area and holding the flame. The planar laser-induced fluorescence (PLIF) of OH radicals together with the flame chemiluminescence imaging were employed to study the flame characteristics under the conditions with and without Quarl using CH4 as fuel to understand the influence of Quarl on the flame. When there is no Quarl, the flame has more freedom to expand at the burner exit and with an increase in the global equivalence ratio (ϕ), the width of the flame increases and the total extension of the flame shortens. For all the global ϕ considered here, the total extension of the flame is shorter under the condition without Quarl in comparison to the one with Quarl. For a richer global ϕ (ϕ ≥ 0.46) the outer recirculation zones (ORZs) are not observed under the condition with Quarl, but are observed without Quarl along with the inner recirculation zone. Without Quarl conditions, equivalence ratios (ϕ) of the concentrically arranged three sections of the burner: an outer Main section, an intermediate section (Pilot) and a central pilot body or pre-chamber combustor, termed the RPL (Rich-Pilot-Lean) sections were altered. The results show that at a constant global ϕ, with an increase in the RPL ϕ and the Pilot ϕ, the flame shortens and expands radially as well as the flame stabilization zone that is produced after the burner exit moves further downstream. At a richer global ϕ, the ORZ is observed along with the inner recirculation zone of the flame. Otherwise, with an increase in global ϕ, the changes in the flame shape, in the flame fluctuation and in the flame stabilization position follow similar trends as for increasing the Pilot ϕ and the RPL ϕ. Additionally, combustion emissions were obtained to observe the effects on NOX level for different operating conditions with and without Quarl.

Investigation of Fuel and Load Flexibility in a SGT-600/700/800 Burner Under Atmospheric Pressure Conditions Using High-Speed Oh-Plif and Oh Chemiluminescence Imaging

2021 ◽  
Author(s):  
Arman Ahamed Subash ◽  
Haisol Kim ◽  
Sven-Inge Möller ◽  
Mattias Richter ◽  
Christian Brackmann ◽  
...  
Keyword(s):  
Atmospheric Pressure ◽  
Gas Turbines ◽  
High Speed ◽  
Recirculation Zone ◽  
Burning Velocity ◽  
Flame Stabilization ◽  
Operating Conditions ◽  
Optical Measurements ◽  
Experimental Investigations ◽  
Pilot Fuel

Abstract Experimental investigations were performed using a standard 3rd generation dry low emission (DLE) burner under atmospheric pressure to study the effect of central and pilot fuel addition, load variations and H2 enrichment in a NG flame. High-speed OH-PLIF and OH-chemiluminescence imaging were employed to investigate the flame stabilization, flame turbulence interactions, and flame dynamics. Along with the optical measurements, combustion emissions were recorded to observe the effect of changing operating conditions on NOX level. The burner is used in Siemens industrial gas turbines SGT-600, SGT-700 and SGT-800 with minor hardware differences. This study thus is a step to characterize fuel and load flexibility for these turbines. Without pilot and central fuel injections in the current burner configuration, the main flame is stabilized creating a central recirculation zone. Addition of the pilot fuel strengthens the outer recirculation zone (ORZ) and moves the flame slightly downstream, whereas the flame moves upstream without affecting the ORZ when central fuel injection is added. The flame was investigated utilizing H2/NG fuel mixtures where the H2 amount was changed from 0 to 100%. The flame becomes more compact, the anchoring position moves closer to the burner exit and the OH signal distribution becomes more distinct for H2 addition due to increased reaction rate, diffusivity, and laminar burning velocity. Changing the load from part to base, similar trends were observed in the flame behavior but in this case due to the higher heat release because of increased turbulence intensity.

Flame Investigation of a Gas Turbine Central Pilot Body Burner at Atmospheric Pressure Conditions Using OH PLIF and High-Speed Flame Chemiluminescence Imaging

2015 ◽  
Author(s):  
Arman Ahamed Subash ◽  
Ronald Whiddon ◽  
Robert Collin ◽  
Marcus Aldén ◽  
Atanu Kundu ◽  
...  
Keyword(s):  
Residence Time ◽  
Atmospheric Pressure ◽  
High Speed ◽  
Combustion Products ◽  
Flame Stabilization ◽  
Operating Conditions ◽  
Time Resolved ◽  
Burner Exit ◽  
Planar Laser ◽  
Primary Combustion Products

Experiments were performed on the central pilot body (RPL-rich-pilot-lean) of Siemens prototype 4th generation DLE burner to investigate the flame behavior at atmospheric pressure condition when varying equivalence ratio, residence time and co-flow temperature. The flame at the RPL burner exit was investigated applying OH planar laser-induced fluorescence (PLIF) and high-speed chemiluminescence imaging. The results from chemiluminescence imaging and OH PLIF show that the size and shape of the flame are clearly affected by the variation in operating conditions. For both preheated and non-preheated co-flow cases, at lean equivalence ratios combustion starts early inside the burner and primary combustion comes to near completion inside the burner if residence time permits. For rich conditions, the unburnt fuel escapes out through the burner exit along with primary combustion products and combustion subsequently restarts downstream the burner at leaner condition and in a diffuse-like manner. For preheated co-flow, most of the operating conditions yield similar OH PLIF distributions and the flame is stabilizing at approximately the same spatial positions. It reveals the importance of the preheating co-flow for flame stabilization. Flame instabilities were observed and Proper Orthogonal Decomposition (POD) is applied to time resolved chemiluminescence data to demonstrate how the flame is oscillating. Preheating has strong influence on the oscillation frequency. Additionally, combustion emissions were analyzed to observe the effect on NOX level for variation in operating conditions.

Investigation of Fuel and Load Flexibility in a SGT-600/700/800 Burner Under Atmospheric Pressure Conditions Using High-Speed OH-PLIF and OH Chemiluminescence Imaging

2020 ◽  
Author(s):  
Arman Ahamed Subash ◽  
Haisol Kim ◽  
Sven-Inge Möller ◽  
Mattias Richter ◽  
Christian Brackmann ◽  
...  
Keyword(s):  
Atmospheric Pressure ◽  
Gas Turbines ◽  
High Speed ◽  
Recirculation Zone ◽  
Flame Stabilization ◽  
Operating Conditions ◽  
Oh Radicals ◽  
Load Variations ◽  
Pilot Fuel ◽  
Industrial Gas Turbines

Abstract Fuel and load flexibility have been increasingly important features of industrial gas turbines in order to meet the demand for increased utilization of renewable fuels and to provide a way to balance the grid fluctuations due to the unsteady supply of wind and solar power. Experimental investigations were performed using a standard 3rd generation dry low emission (DLE) burner under atmospheric pressure conditions to study the effect of central and pilot fuel addition, load variations and hydrogen (H2) enrichment in a natural gas (NG) flame. High-speed kHz planar laser-induced fluorescence (PLIF) of OH radicals and imaging of OH chemiluminescence were employed to investigate the flame stabilization, flame turbulence interactions, and flame dynamics. Along with the optical measurements, combustion emissions were also recorded to observe the effect of changing operating conditions on NOX level. The burner is used in Siemens industrial gas turbines SGT-600, SGT-700 and SGT-800 with no hardware differences and the study thus is a step to characterize fuel and load flexibility for these turbines. Without pilot and central fuel injections in the current burner configuration, the main flame is stabilized creating a central recirculation zone (CRZ). Addition of the pilot fuel strengthens the outer recirculation zone (ORZ) and moves the flame anchoring position slightly downstream, whereas the flame moves upstream without affecting the ORZ when central fuel injection is added. The flame was investigated utilizing H2/NG fuel mixtures where the H2 amount was changed from 0 to 100%. The results show that the characteristics of the flames are clearly affected by the addition of H2 and by the load variations. The flame becomes more compact, the anchoring position moves closer to the burner exit and the OH signal distribution becomes more distinct for H2 addition due to increased reaction rate, diffusivity, and laminar burning velocity. Changing the load from part to base, similar trends were observed in the flame behavior but in this case due to the higher heat release because of increased turbulence intensity.

Low NOx Premixed Combustion of MBtu Fuels in a Research Burner

1997 ◽  
Vol 119 (3) ◽  
pp. 553-558 ◽  
Author(s):  
K. Do¨bbeling ◽  
A. Eroglu ◽  
D. Winkler ◽  
T. Sattelmayer ◽  
W. Keppel
Keyword(s):  
High Pressure ◽  
Quartz Glass ◽  
Atmospheric Pressure ◽  
Fuel Injection ◽  
Flame Stabilization ◽  
Premix Combustion ◽  
Planar Laser ◽  
Preliminary Study ◽  
Combustion Tests

The paper reports on the development and testing of a premix research burner for MBtu fuels. The burner has a quartz glass annular mixing section and a quartz, glass flame tube to allow visualization of the flame. A central lance is used to mount modules for fuel injection, swirl generation, and flame stabilization. This allows a large number of variants with different swirl strength, mixing section length, fuel injection geometry, and flameholder size and shape to be easily tested. Experiments have been performed at atmospheric pressure and under high-pressure conditions (14 bar pressure, 400°C air preheat temperature) for syngas with a H2/CO ratio of up to 5. In a preliminary study, the mixing quality of the tested variants has been assessed with planar laser-induced fluorescence (LIF). High-pressure combustion tests show that low NOx (<10 vppmd @ 15 percent O2) premix combustion of MBtu fuels under industrial GT conditions without dilution is feasible.

Pilot-Pilot Interaction Effects on a Prototype DLE Gas Turbine Burner Combustion

2016 ◽  
Author(s):  
Atanu Kundu ◽  
Jens Klingmann ◽  
Arman Ahamed Subash ◽  
Robert Collin
Keyword(s):  
Gas Turbine ◽  
Residence Time ◽  
Interaction Effect ◽  
Flame Stabilization ◽  
Experimental Results ◽  
Optical Measurements ◽  
Pollutant Emissions ◽  
Total Power ◽  
Low Emission ◽  
Pilot Fuel

Lean premixed dry low emission (DLE) combustion system in a gas turbine engine is a globally accepted concept to reduce pollutant emissions and to improve combustion efficiency. This study is focused on an industrial downscaled prototype burner (4th Generation Dry Low Emission Burner for SGT-750 designed and manufactured by Siemens Industrial Turbo machinery AB), which has been tested extensively at atmospheric conditions. To enhance the operability and alleviate flame dynamics behavior, multiple fuel and air circuits (i.e. Rich-Pilot-Lean (RPL), Pilot and Main) are engaged in the burner. Primarily, present study evaluates the RPL-Pilot interaction effect on the main combustion zone. A highly swirled flow from the burner exit produces a central recirculation zones (CRZ) to recirculate the hot vitiated gas for sustaining the combustion process. The main flame is stabilized in the inner shear layer (ISL), which is found in the diverging section (named as Quarl). The total power of the burner was varied between 70–140 kW and the fuel used for the experiment was 99.5% pure methane. A short length quartz liner was used for the experiment and the residence time of the combustor is 9 ms. At the liner exit, emission sampling (CO, NOx) has been conducted using a water-cooled emission probe. Optical measurements were permitted, as the Quarl and combustor liner were optically accessible. Planar laser-induced fluorescence of OH molecule (OH-PLIF) and natural chemiluminescence measurements were conducted to visualize the flame characteristics and its response by changing the RPL and Pilot fuel splits. A comprehensive study was performed by varying the RPL residence time to investigate the main flame stabilization and pollutant formation of the burner. Higher RPL residence time exhibits NOx benefits but at the same time flame instability was increased. Pilot fuel percentage modification demonstrate negative impact on NOx formation due to the limited mixing of fuel and air. With the increase of Pilot fuel split, CO emission decreases, which is advantageous for increasing the LBO margin. The study has identified a number of critical situations where the flame was stabilized without any RPL and Pilot combustion. Apart from the experimental results, a simple reactor network model has been applied for predicting NOx emission. Different kinetic mechanisms were assessed and the prediction results are compared to experimental results. Heat loss from the combustor wall played a significant role on emission formation and was included in the reactor model. This study provides a good understanding of the new DLE industrial burner concept and the RPL-pilot interaction effect on the emission.

Laminar Flame Velocity of Syngas Fuels

2010 ◽  
Author(s):  
Bidhan Dam ◽  
Vishwanath Ardha ◽  
Ahsan Choudhuri
Keyword(s):  
Laminar Flame ◽  
Burning Velocity ◽  
Flame Velocity ◽  
Laminar Burning Velocity ◽  
Velocity Data ◽  
Flame Propagation Velocity ◽  
Exit Velocity ◽  
Flat Flame ◽  
Burner Exit

The paper presents the experimental measurements of the laminar burning velocity of H2-CO mixtures. Hydrogen (H2) and carbon monoxide (CO) are the two primary constituents of syngas fuels. Three burner systems (nozzle, tubular, and flat flame) are used to quantify the effects of burner exit velocity profiles on the determination of laminar flame propagation velocity. The effects to N2 and CO2 diluents have been investigated as well, and it is observed that the effects of N2 and CO2 on the mixture burning velocity are significantly different. Finally, the burning velocity data of various syngas compositions (brown, bituminous, lignite and coke) are presented.

Laminar Flame Speed Measurements of H2/CO/CO2 Mixtures Up to 15 atm and 600 K Preheat Temperature

2008 ◽  
Author(s):  
J. Natarajan ◽  
Y. Kochar ◽  
T. Lieuwen ◽  
J. Seitzman
Keyword(s):  
Temperature Dependence ◽  
Atmospheric Pressure ◽  
Radiation Effects ◽  
Laminar Flame ◽  
Elevated Pressure ◽  
Flame Speed ◽  
Preheat Temperature ◽  
Numerical Predictions ◽  
Kinetic Mechanisms ◽  
Fuel Mixtures

Laminar flame speeds of lean H2/CO/CO2 (syngas) fuel mixtures have been measured for a range of H2 levels (20–90% of the fuel) at pressures and reactant preheat temperatures relevant to gas turbine combustors (up to 15 atm and 600 K). A conical flame stabilized on a contoured nozzle is used for the flame speed measurement, which is based on the reaction zone area calculated from chemiluminescence imaging of the flame. A O2:He mixture (1:9 by volume) is used as the oxidizer, rather than standard air, in order to suppress the hydrodynamic and thermo-diffusive instabilities that become prominent at elevated pressure conditions for lean H2/CO fuel mixtures. All the measurements are compared with numerical predictions based on two leading kinetic mechanisms: the H2/CO mechanism of Davis et al. and the C1 mechanism of Li et al. The results generally agree with the findings of an earlier study at atmospheric pressure: 1) for low H2 content (<40%) fuels, the model predictions are in good agreement with measurements at both 300 K and 600 K preheat temperature; but 2) the models tend to over predict the temperature dependence of the flame speed for medium (∼40–60%) and high (> 60%) H2 content fuels, especially at very lean conditions. The elevated pressure (∼15 atm) results, however, reveal that the effect is less pronounced than at atmospheric pressure. The exaggerated temperature dependence of the current models may be due to errors in the temperature dependence used for so-called “low temperature” reactions that become more important as the preheat temperature is increased. The radiation effects associated with CO2 addition to the fuel (up to 40%) is found to be less important for medium and high H2 content syngas fuels at elevated pressure and preheat temperature.

Low NOx Premixed Combustion of MBtu Fuels in a Research Burner

1996 ◽  
Author(s):  
K. Döbbeling ◽  
A. Eroglu ◽  
D. Winkler ◽  
T. Sattelmayer ◽  
W. Keppel
Keyword(s):  
High Pressure ◽  
Quartz Glass ◽  
Atmospheric Pressure ◽  
Fuel Injection ◽  
Flame Stabilization ◽  
Premix Combustion ◽  
Planar Laser ◽  
Preliminary Study ◽  
Combustion Tests

The paper reports on the development and testing of a premix research burner for MBtu fuels. The burner has a quartz glass annular mixing section and a quartz glass flame tube to allow visualization of the flame. A central lance is used to mount modules for fuel injection, swirl generation and flame stabilization. This allows a large number of variants with different swirl strength, mixing section length, fuel injection geometry and flameholder size and shape to be easily tested. Experiments have been performed at atmospheric pressure and under high pressure conditions (14 bar pressure, 400°C air preheat temperature) for syngas with a H2/CO ratio of up to 5. In a preliminary study the mixing quality of the tested variants has been assessed with planar laser induced fluorescence (LIF). High pressure combustion tests show that low NOx (< 10 vppmd @ 15% O2) premix combustion of MBtu fuels under industrial GT conditions without dilution is feasible.

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