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

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.

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

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.

Combustion Characteristics of Fuel Staged Combustor for Aeroengines at LTO Cycle Conditions

2011 ◽  
Author(s):  
Takeshi Yamamoto ◽  
Kazuo Shimodaira ◽  
Yoji Kurosawa ◽  
Seiji Yoshida
Keyword(s):  
Pressure Ratio ◽  
Nox Reduction ◽  
Combustion Characteristics ◽  
Nox Emissions ◽  
Staged Combustion ◽  
Drastic Reduction ◽  
Fuel Nozzle ◽  
Reduction Of Nox

In JAXA, combustion technologies have been developed with an aggressive target that is an 80% NOx reduction of CAEP/4. For the drastic reduction of NOx emissions, a fuel nozzle was designed based on the lean staged combustion concept. This paper describes single-sector combustor tests of a fuel staged combustor at ICAO LTO cycle conditions of an assumed engine with rated output of 40 kN and overall pressure ratio of 25.8. The results showed that the combustor enables a 77% reduction of the NOx standard of CAEP/4.

A Comprehensive Approach to NOx Reduction Without Low NOx Burners

2005 ◽  
Author(s):  
Stephen K. Storm ◽  
Maureen M. Moss
Keyword(s):  
Performance Optimization ◽  
Systems Approach ◽  
Traditional Approach ◽  
Nox Reduction ◽  
Maximum Load ◽  
Comprehensive Approach ◽  
Present System ◽  
Staged Combustion ◽  
Complete Combustion ◽  
Combustion Optimization

The traditional approach to reduce NOx has been to retrofit and install commercially available “plug-in” Low NOx burners. Typically, these use a combination of internal staging and are often used in conjunction with over-fire air to create off-stochiometric or staged combustion. That is, the complete combustion of the fuel occurs in several stages. Often, well designed Low NOx burners are installed without a comprehensive systems approach. The typical challenges associated with staged combustion are related to the fact that burner performance must be nearly perfect to complete combustion within the available residence time of the furnace. Specifically, attention to airflow measurement and control by use of reliable & repeatable venturis and with pulverizer performance optimization. To maintain or improve this unit’s excellent reliability, a focus on optimizing the inputs and completing the combustion prior to the furnace exit was implemented. The goals of this project were as follows: 1. NOx Reduction from .78lb/mmBtu(full load) – 1.0#/mmBtu(low load) to less than 0.36 lb/mmBtu; 2. Flyash Carbon Content less than 10%; 3. Combustion Optimization; 4. Minimal slagging; 5. Maintain the same as baseline FEGT or reduce FEGT; 6. Maximum Load Capability; 7. Maximum Fuel Flexibility; 8. Complete the project at the lowest cost per kW possible (with the best results). All of the goals were accomplished. The technical success of this project is the results of applying a systematic and comprehensive approach beginning with raw coal feed to the pulverizers. The benefits of this total combustion optimization project is that later when additional NOx reductions are required, they can be added as a complimentary change to the present system. For example, if this unit is later equipped with SNCR or SCR, reduced rates of ammonia will be required, there will be reduced “popcorn ash” production, and less SCR catalyst wear and overall unit improved performance and reliability.

Study of NOx Inhibition Technology Based on Water-Gas Reaction

2015 ◽  
Vol 737 ◽  
pp. 584-587
Author(s):  
Tian Hua Wu ◽  
Ren Zhang Qian
Keyword(s):  
Coal Combustion ◽  
Nox Reduction ◽  
Pulverized Coal ◽  
Peak Temperature ◽  
Emission Sources ◽  
Pulverized Coal Combustion ◽  
Staged Combustion ◽  
Combustion Technology ◽  
Low Nox Combustion ◽  
Water Gas

Pulverized coal combustion is one of the main NOx emission sources. The existing low NOx combustion technology can not meet the requirements of environment conservation. In this paper, a new low NOx combustion technology, the NOx inhibition method based on water-gas reaction, is presented, in which steam is injected into the anoxic flame of pulverized coal to bring water-gas reaction and produce CO and H2 which will inhibit the production of NOx. The produced H2 is especially very active. Water-gas reaction is endothermic, which has an effect of reducing the peak temperature of the flame and is very propitious to the inhibition of thermal type NOx. As the water-gas reaction is also an interim process, the heat absorbed in it will be released when burning with oxygen so that the whole amount of heat inside the furnace is not affected. The principle of the method is proved correct by experiments and industrial scale of 420 t/h boiler tests in which the effect of NOx reduction is obvious. The technology is consistent with that of air-staged combustion.

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