• 한국연소학회:학술대회논문집
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• 한국연소학회 2001년도 제23회 KOSCO SYMPOSIUM 논문집
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• pp.17-26
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• 2001

Self flue gas recirculation flow is an effective method for low NOx emission in the regenerative low NOx burner. The object of this study is to analyze the self flue gas recirculating flow by varying jet velocity of the combustion air. Fuel and air flow rates are fixed and combustion air jet nozzle diameters are 13, 6.5 and 5mm. The stoichiometric line is obtained from the concentration of the fuel using an acetone PLIF technique. It is found that the self flue gas recirculating flow is entrained into that line using a two color PIV technique. As the jet velocity of combustion air is increased, the flue gas entrainment rate into the stoichiometric line is increased. This result suggests that NOx emission can be reduced due to the effects of flue gas which is lowering the flame temperatures.

• 한국연소학회지
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• 제6권1호
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• pp.20-28
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• 2001

Self flue gas recirculation flow is an effective method for low NOx emission in a regenerative low NOx burner. The object of this study is to analyze self flue gas recirculating flow by varying the jet velocity of the combustion air. Fuel and air flow rates are fixed and combustion air jet nozzle diameters are 13, 6.5 and 5mm. The stoichiometric line is obtained from the concentration of fuel using the acetone PLIF technique. It is found that self flue gas recirculating flow is entrained into that line using the two color PIV technique. As the jet velocity of combustion air is increased, the flue gas entrainment rate into the stoichiometric line is increased. This result suggests that NOx emission can be reduced due to the effects of flue gas lowering the flame temperature.

• 한국연소학회지
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• 제14권1호
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• pp.19-24
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• 2009

A novel low NOx oil burner of 0.7 MW (for a 1 ton steam/hr industrial boiler) was designed and tested to investigate the combustion characteristics through in-flame measurement and flue gas analysis. Flame shape was observed by CCD camera and $CH^*/{C_2}^*$ radical distribution in the flame were observed, along with measurement of flue gas composition such as NOx and CO, for various heat inputs, excess airs and pressure of the fuel spary nozzles. The flame showed the two-zone structure: fuel-rich and fuel-lean zone, which was very favorable for the low-NOx combustion, and the NOx emission for haevy oil combustion was significantly reduced to < 150 ppm at 4 % $O_2$, compared with the NOx level of a conventional heavy oil burner.

• 대한기계학회논문집B
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• 제28권11호
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• pp.1339-1347
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• 2004

Development of the low NOx heating boiler was strongly asked due to severe air pollution and the large number of boilers in korea. Compactness of the commercial boiler was also important because of low manufacturing cost and easy installation. In this study. newly developed compact low NOx burner, using turbulent gas diffusion combustion with multi-staged air supplies and multiple fuel nozzles, was investigated. Comparison study of the new burner was performed between experimental results and computational analysis. Commercial computational fluid dynamic(CFD) program named CFX-5.6 was used for numerical analysis of the low NOx burner inside the test combustor. Comparisons of experiment data and numerical result were performed under various equivalence ratio and fuel flow rate.

• 연구논문집
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• 통권27호
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• pp.101-108
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• 1997

The characteristics of combustion and emissions in multi-staged oil burner have been experimentally studied for the various range of equivalence ratios, drop sizes and fuel formulations. Malvern system was used to measure droplet size of fuel. Light fuel oil and light fuel oil doped with pyridine($C_5H _5N$) were used to investigate the effects on fuel NOx emission. The emissions of NO and CO in exhaust gas and the flame temperatures were measured by the gas analyzer and thennocouples. NOx emissions were increased by increasing the excess air ratio (range:$lambda=1.1-1.4$) or decreasing the SMD of droplet in single-staged burner. In comparison with the single-staged burner, the emission of NOx in multi-staged burner was reduced by 50% but CO emission was slightly increased. It is found that multi-staged burner has a good capability in reducing thermal NOx resulting from the distributed heat release rate and lower flame temperature in fuel-rich and fuel-lean combustion zone. Moreover, the fuel NOx emission of the multi-staged burner is lower than that of single-staged burner, because multi-staged burner has fuel rich zone where fuel N is converted to $N_2$ more than NO. In 3-staged burner, the percentage of each stage combustion air have strong influence on emission characteristics. It is also found that NOx emission can be reduced by decreasing inner and outer air percentage or increasing middle air flow rate and CO emission is vice versa.

• 한국에너지공학회:학술대회논문집
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• 한국에너지공학회 1999년도 춘계 학술발표회 논문집
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• pp.89-93
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• 1999

Experimental studies are conducted to investigate the flame stability and the thermal/fuel NOx formation characteristics of the low calorific value(LCV) gas fuel. Synthetic LCV fuel gas is produced through mixing carbon monoxide, hydrogen, nitrogen and ammonia on the basis that the thermal input of the syngas fuel into a burner is identical to that of natural gas, and then the syngas mixture is fed to and burnt with air on flat flame burner. Flame behaviors are observed to identify flame instability due to blow-off or flash-back when burning the LCV fuel gas at various equivalence ratio conditions. Measurements of NOx in combustion gas are made for comparing thermal and fuel NOx emissions from the LCV syngas combustion with those of the natural gas one, and for analyzing ammonia to NOx conversion mechanism. In addition, the nitrogen dilution of the LCV syngas is preliminarily attempted as a NOx reduction technique.

• 한국연소학회:학술대회논문집
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• 한국연소학회 2004년도 제28회 KOSCO SYMPOSIUM 논문집
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• pp.248-255
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• 2004

For the compactness of regenerative combustion, self regenerative combustion and embedding regenerator inside furnace are proposed. The Self Regenerative burner system was developed to enhance thermal efficiency and Low Nox emission. In the twin regenerative system, two burner heads are generally used for preheating and exhausting combustion mode. But self regenerative burner system use only single nozzle body for regenerative combustion. Also two kind of regenerator, internal and external type, were designed to operate conveniently in both large and small furnace. According to test result, the self regenerative combustion system gives strong internal exhaust gas recirculation that reduce NOx emission significantly. NOx was measured as 50ppm(5% O2, 1290C furnace temperature). Also it is found that the fuel saving rate due to the self regenerative burner system reach to 30-40%. Thus it can be concluded that self regenerative mild combustion system appears to provide a reasonable regenerative burner for compactness and high performance as compared with conventional twin regenerative burner system. Also in the RT Application , compact twin regenerative burner was developed with the help of embedding regenerator inside furnace.

• 한국산학기술학회논문지
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• 제19권6호
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• pp.696-701
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• 2018

연소 반응 시 발생하는 질소산화물은 산성비와 미세먼지 발생에 많은 영향을 미치는 물질이다. 이에 대한 저감 방법으로 고비용의 탈질설비 대신 지연연소 등의 방법에 대한 연구가 많이 이루어지고 있다. 이러한 연구들 중에 적은 양의 공기로 많은 양의 배기가스를 재순환 할 수 있는 코안다 노즐을 이용한 배기가스 재순환 연소에 대한 연구가 최근에 이루어지고 있다. 본 연구에서는 배기가스 재순환 배관에 코안다 노즐을 사용하여 배기가스를 재순환하는 재순환 버너의 양쪽 출구가 트인 형상에 대하여 전산유체해석을 통해 연구를 수행하였으며 연소 유동의 압력, 유선, 온도, 연소 반응 속도와 질소산화물의 분포 특성을 살펴보았다. 배기가스를 재순환하여 연소용 공기와 혼합된 기체가 원통의 접선방향으로 유입되어 연료노즐 출구 부근에서 압력이 낮은 영역이 존재하고 이에 따라 원통 버너의 중심부근에는 버너의 가운데 부분으로 역류가 형성되며 가장자리 부분으로 배기가스가 배출되는 것을 확인하였다. 배기가스가 유입되는 부분이 버너의 오른쪽에 있어서 버너의 오른쪽으로 연소반응이 일어나며 상대적으로 온도분포와 NOx 분포가 높게 나타났다. 연소용 공기비를 1.0에서 1.8까지 변화하여 NOx 생성을 관찰한 결과, 공기비가 1.0에서 1.5까지는 평균 NOx 생성이 감소하다가 공기비가 1.8일 때 급격히 증가하는데 이는 NOx 생성 반응은 온도의 지수승에 비례하게 되는데 공기비가 1.5이상이 되면서 온도의 영향을 많이 받아서 NOx 생성 반응이 오른쪽 영역에서 급격히 증가하는 것으로 판단된다.

• 대한기계학회논문집B
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• 제33권10호
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• pp.767-772
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• 2009

The demand for a boiler with low NOx burner is increasing with the recent strict NOx regulation. Staged burner is a common low NOx burner to suppress the formation of thermal NOx by yielding local fuel rich and lean condition. The staged burner gives fire with bigger frontal area and length compared with a conventional burner, which changes heat transfer characteristics in the combustion chamber. The heat transfer and exhaust gas characteristics have been studied in the present study for a 0.5 t/h class furnace type boiler adopting the staged burner. A numerical simulation has been conducted to clarify the detailed physics inside the combustion chamber.

• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2008년도 춘계학술대회논문집
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• pp.555-558
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• 2008

The demand for a boiler with low NOx burner is increasing with the recent strict NOx regulation. Staged burner is a common low NOx burner to suppress the formation of thermal NOx by yielding local fuel rich and fuel lean condition. The staged burner gives fire with bigger frontal area and length compared with a conventional burner, which changes heat transfer characteristics in the combustion chamber. The heat transfer and exhaust gas characteristics has been studied in the present study for a 0.5 t/h class furnace type boiler adopting the staged burner. A numerical simulation has been conducted to clarify the detailed physics inside the combustion chamber.