NOx Reduction Strategy by Staged Combustion with Plasma-Assisted Flame Stabilization

2012 ◽  
Vol 26 (7) ◽  
pp. 4284-4290 ◽  
Author(s):  
Dae Hoon Lee ◽  
Kwan-Tae Kim ◽  
Hee Seok Kang ◽  
Young-Hoon Song ◽  
Jae Eon Park
Keyword(s):  
Nox Reduction ◽  
Flame Stabilization ◽  
Staged Combustion ◽  
Reduction Strategy

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.

NOx Reduction for RPF Gasification Gas by a Staged Combustion with External Oscillation

2015 ◽  
Vol 32 (5) ◽  
pp. 436-443
Author(s):  
Eun Hyuk Kim ◽  
Young Nam Chun
Keyword(s):  
Nox Reduction ◽  
Staged Combustion ◽  
External Oscillation

An In-Cycle based NOx Reduction Strategy using Direct Injection of AdBlue

2014 ◽  
Vol 7 (4) ◽  
pp. 1984-1996 ◽  
Author(s):  
Kenan Muric ◽  
Ola Stenlaas ◽  
Per Tunestal ◽  
Bengt Johansson
Keyword(s):  
Direct Injection ◽  
Nox Reduction ◽  
Reduction Strategy

A Model for Predicting the Lift-Off Height of Premixed Jets in Vitiated Cross Flow

2015 ◽  
Author(s):  
Michael Kolb ◽  
Denise Ahrens ◽  
Christoph Hirsch ◽  
Thomas Sattelmayer
Keyword(s):  
Time Scale ◽  
Ignition Delay ◽  
Gas Turbines ◽  
Cross Flow ◽  
Flame Stabilization ◽  
Staged Combustion ◽  
Flow Temperature ◽  
Jet Flame ◽  
Stage Combustion ◽  
Lift Off

Lean premixed single-stage combustion is state of the art for low pollution combustion in heavy-duty gas turbines with gaseous fuels. The application of premixed jets in multi-stage combustion to lower nitric oxide emissions and enhance turndown ratio is a novel promising approach. At the Lehrstuhl für Thermodynamik, Technische Universität München, a large scale atmospheric combustion test rig has been set up for studying staged combustion. The understanding of lift-off behavior is crucial for determining the amount of mixing before ignition and for avoiding flames anchoring at the combustor walls. This experiment studies jet lift-off depending on jet equivalence ratio (0.58–0.82), jet preheat temperature (288–673 K), cross flow temperature (1634–1821 K) and jet momentum ratio (6–210). The differences to existing lift-off studies are the high cross flow temperature and applying a premixed jet. The lift-off height of the jet flame is determined by OH* chemiluminescence images, and subsequently, the data is used to analyze the influence of each parameter and to develop a model that predicts the lift-off height for similar staged combustion systems. A main outcome of this work is that the lift-off height in a high temperature cross flow cannot be described by one dimensionless number like Damköhler- or Karlovitz number. Furthermore, the ignition delay time scale τign also misses part of the lift-off height mechanism. The presented model uses turbulent time scales, the ignition delay and a chemical time scale based on the laminar flame speed. An analysis of the model reveals flame stabilization mechanisms and explains the importance of different time scale.

Synergistic effect of co-firing woody biomass with coal on NOx reduction and burnout during air-staged combustion

2016 ◽  
Vol 71 ◽  
pp. 114-125 ◽  
Author(s):  
Yonmo Sung ◽  
Sangmin Lee ◽  
Changhyun Kim ◽  
Dongheon Jun ◽  
Cheoreon Moon ◽  
...  
Keyword(s):  
Synergistic Effect ◽  
Nox Reduction ◽  
Woody Biomass ◽  
Staged Combustion

Optimized In Cylinder NOx Reduction Strategy for Meeting BSVI Emission Limits

2019 ◽  
Author(s):  
Anbarasu Muthusamy ◽  
Vagesh Shangar Ramani ◽  
Pranav Kumar Sinha ◽  
Giftson J ◽  
Sivasubramamanian R ◽  
...  
Keyword(s):  
Nox Reduction ◽  
Reduction Strategy ◽  
Emission Limits

A Model for Predicting the Lift-Off Height of Premixed Jets in Vitiated Cross Flow

2016 ◽  
Vol 138 (8) ◽  
Author(s):  
Michael Kolb ◽  
Denise Ahrens ◽  
Christoph Hirsch ◽  
Thomas Sattelmayer
Keyword(s):  
Time Scale ◽  
Ignition Delay ◽  
Gas Turbines ◽  
Cross Flow ◽  
Flame Stabilization ◽  
Dimensionless Number ◽  
Staged Combustion ◽  
Flow Temperature ◽  
Jet Flame ◽  
Lift Off

Lean premixed single-stage combustion is state of the art for low pollution combustion in heavy-duty gas turbines with gaseous fuels. The application of premixed jets in multistage combustion to lower nitric oxide emissions and enhance turn-down ratio is a novel promising approach. At the Lehrstuhl für Thermodynamik, Technische Universität München, a large-scale atmospheric combustion test rig has been set up for studying staged combustion. The understanding of lift-off (LO) behavior is crucial for determining the amount of mixing before ignition and for avoiding flames anchoring at the combustor walls. This experiment studies jet LO depending on jet equivalence ratio (0.58–0.82), jet preheat temperature (288–673 K), cross flow temperature (1634–1821 K), and jet momentum ratio (6–210). The differences to existing LO studies are the high cross flow temperature and applying a premixed jet. The LO height of the jet flame is determined by OH* chemiluminescence images, and subsequently, the data is used to analyze the influence of each parameter and to develop a model that predicts the LO height for similar staged combustion systems. A main outcome of this work is that the LO height in a high temperature cross flow cannot be described by one dimensionless number like Damköhler- or Karlovitz-number. Furthermore, the ignition delay time scale τign also misses part of the LO height mechanism. The presented model uses turbulent time scales, the ignition delay, and a chemical time scale based on the laminar flame speed. An analysis of the model reveals flame stabilization mechanisms and explains the importance of different time scale.

Characterization of a Real Size Retrofittable Catalytic Combustion System

2008 ◽  
Author(s):  
Olaf Diers ◽  
Michael Fischer ◽  
Johannes Heinze ◽  
Johan Koopman ◽  
Denis Schneider ◽  
...  
Keyword(s):  
Nox Reduction ◽  
Gas Analysis ◽  
Flame Stabilization ◽  
Catalytic Reactor ◽  
Atmospheric Conditions ◽  
Reactor Model ◽  
Nox Formation ◽  
Radial Temperature ◽  
Stirred Reactor ◽  
Anti Stokes

This contribution describes the investigation of an engine-scale catalytic hybrid burner. The burner has been investigated under atmospheric conditions with preheated air and natural gas fuel in two operating points, with and without the catalytic reactor. By using the catalyst, an extension of the operating range to leaner stoichiometries has been demonstrated. Exhaust gas analysis performed directly downstream of the burner as well as in the burner far-field showed a NOx reduction potential of more than 20% when employing the catalyst. For the operation with the catalytic reactor, the flame stabilization process and dependency of NOx formation on the piloting gas ratio is described with results of OH chemiluminescence measurements. Radial temperature profiles taken with Coherent Anti Stokes Raman Scattering (CARS) suggest a reaction delay directly downstream of the catalytic section of the burner. Calculations with a perfectly stirred reactor model help to obtain a better understanding of the kinetics of the hot gases leaving the catalyst section.

Application Analysis on the Bias and Air Staged Combustion Technology in the Opposed Firing Boiler

2011 ◽  
Author(s):  
Tai-sheng Liu
Keyword(s):  
Recirculation Zone ◽  
Nox Reduction ◽  
Pulverized Coal ◽  
Nox Emission ◽  
Unburned Carbon ◽  
Staged Combustion ◽  
Bias Model ◽  
Combustion Technology ◽  
Radial Model ◽  
Low Nox Emission

The bias combustion technology has been widely used in the swirling burner. Take the distribution of the pulverized-coal concentration at the primary air outlet as the division principle, there are three kinds of bias combustion models: radial model with inside dense and outside lean, radial model with outside dense and inside lean, and circumferential model. Considering stable ignition and low NOx emission, at the phase of the pulverized-coal ignition, the dense pulverized-coal flow should be heated by the high temperature flue gas intensively and quickly to ensure the coal’s timely ignition and form an In-flame NOx reduction zone for low NOx emission. Hence the bias combustion technology should be in accordance with the recirculation zone. So the radial bias model with inside dense and outside lean suits to central recirculation zone while radial bias model with outside dense and inside lean suits to annular recirculation zone. The circumferential bias model suits to both recirculation zones. Furthermore, appropriate measures should be taken on the burner’s arrangement and furnace’s design to prevent the obvious increase of slagging problem and unburned carbon in fly ash when using bias and air staged combustion technology.

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