• 연구논문집
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• s.27
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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.

• Journal of the Korean Society of Combustion
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• v.12 no.3
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• pp.1-7
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• 2007

A combined hydrogen generator of plasma and catalytic reformer was developed, and was applied to stabilize unstable flame of 200,000 Kcal/hr LPG combustor. The role of the plasma reformer was to generate hydrogen in a short period and to heat-up the catalytic reformer during the start-up time. After the start-up period, the catalytic reformer generates hydrogen through steam reforming with oxygen (SRO) reactions. The maximum capacity of the hydrogen generator was enough 100 lpm to stabilize the flame of the present combustor. In order to reduce NOx and CO emissions simultaneously, 1) FGR (Flue Gas Recirculation) technique has been adopted and 2) the hydrogen was added into the fuel supplied to the combustor. Test results showed that the addition of 25% hydrogen and 30% FGR rate lead to simultaneous decrease of CO and NOx emissions. The technique developed in the present study showed good potential to replace $NH_3$ SCR technique, especially in the small-scale combustor applications.

• 한국연소학회:학술대회논문집
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• 2007.05a
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• pp.187-190
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• 2007

A combined hydrogen generator of plasma and catalytic reformers has been developed, and has been applied to stabilize unstable flame of 200,000 Kcal/hr LPG combustor. The role of the plasma reformer is to generate hydrogen in a short period and to heat-up the catalytic reformer during the start-up time. After the start-up period, the catalytic reformer generates hydrogen through steam reforming with oxygen (SRO) reactions. The maximum capacity of the hydrogen generator is 100 lpm that is sufficient to be used to stabilize the flame of the present combustor. In order to reduce NOx and CO emissions simultaneously, 1) FGR (Flue Gas Recirculation) technique has been adopted and 2) the hydrogen has been added into the fuel supplied to the combustor. Test results shows that 25 % addition of hydrogen and 30 % FGR rate lead to simultaneous decrease of CO and NOx emissions. The technique proposed in the present study shows good potential to replace $NH_3$ SCR technique, especially in the case of small-scale combustor applications.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.25 no.12
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• pp.1793-1801
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• 2001

A study of low NOx atomizer was carried out to reduce nitrogen oxides(NOx) in a liquid fuel burner flame. The basic concept of NOx reduction in this atomizer is the fuel 2-staging combustion which is generated by a single atomizer forming two different stoichiometric flames. Two orifices swirl atomizer was selected and modified to realize this concept, and it was tested to obtain the design process of low NOx atomizer. These experiments were achieved to find out the relationship between the injection pressures and the flow rate, spray angle and drop size of swirl atomizer as well as to confirm the NOx reduction concept in real plant(power boiler). In comparison between experimental and theoretical results, the correct discharge coefficient and spray angle were obtained. In real burning test, NOx reduction rate was reached to above 27% of the case using conventional swirl atomizer.

• Proceedings of the KSME Conference
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• 2004.11a
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• pp.1751-1755
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• 2004

Increasing environmental pressures to reduce NOx emission are being placed on coal-fired boilers. To meet the environmental requirements, Doosan Heavy Industries & Construction Co., Ltd.(Doosan) has developed low NOx pulverized coal burner. Low NOx pulverized coal burner has already delivered, and it's combustion performance was evaluated to the NOx and Unburned Carbon(UBC) during the commissioning tests. The test results are shown that the strong relationship is existed between NOx and OFA flow rate, and also fuel-N fraction of coal has effected on NOx emission.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.25 no.2
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• pp.235-243
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• 2001

This paper describes a design study of the cylindrical multi-hole premixed burner to be used for condensing gas boiler which can raise performance and reduce NOx emission. In this study, specifications of the multi-hole burner (hole diameters and arrangement) are investigated using model flat burners in terms of flame stability, and combustion characteristics for stability and NOx emission are examined for cylindrical multi-hole burner. As a result, the equivalence ratio for optimum operation condition of the cylindrical burner is around 0.72(0.7∼0.75). In this condition, turn-down ratio becomes 3 : 1 at least which is suitable for proportional control. The NOx and CO emission is less than 40ppm and 25ppm(0$_2$0% basis), respectively. This burner can be applied LPG as well as NG because there is no difference for stable combustion region.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.11 no.5
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• pp.109-114
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• 2012

The combustion characteristics using forced pulsating flow were experimentally investigated with confined premixed flames stabilized by a reward-facing step. The intermittent combustion has many merits, for instance, such as high load combustion, high heat transfer, low emission gas, compared with those of continuous combustion. For these purposes, data processing of binary image was conducted to reveal the differences between intermittent and continuous combustion. As the results, it was possible to calculate the reaction zone using OH-emission band and, therefore, showed that forced pulsating flow was useful in combustion technology.

• 한국연소학회:학술대회논문집
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• 2015.12a
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• pp.123-125
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• 2015

A study has been conducted to investigate the effect of swirl angle in low swirl combustor. In this study, the employed swirl angles were $28^{\circ}$, $32^{\circ}$ and $37^{\circ}$. Direct flame photos show that the width of the flame is expanded and the length of the flame is shortened when swirl angle is increased. Also, as the swirl angle was increased, the flame stability region could be widened due to the expansion of lower flammable limit. Between 3 and 7kW, CO emissions was below 10 ppm and NOx emissions was also below 27 ppm at $O_2$ 15% basis over the lean burning range of 0.6 < ${\Phi}$ < 0.9. From this investigation of stability expansion effect and emission performance, it was identified that the swirl angle $37^{\circ}$ is most suitable swirling condition in the low swirl model combustor.

• Journal of the Korean Institute of Gas
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• v.23 no.6
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• pp.8-16
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• 2019

One of the methods for low-pollution combustion, flue gas recirculation(FGR) is effective to reduce nitrogen oxides and it was applied in CH₄/air premixed counterflow flames to identify the change of flame characteristics and NOx mechanisms. Considering that the mole fraction of the products varied depending on the strain rates, the major products: CO₂, H₂O, O₂ and N₂ were recirculated as a diluent to reflect the actual combustion system. With the application of the FGR technique, a turning point of maximum flame temperature under certain strain rate condition was found. Furthermore as the recirculation ratio increased, the tendency of NO was changed before and after the turning point and the analysis on thermal NO and Fenimore NO production was conducted.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.35 no.2
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• pp.137-143
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• 2011

This paper describes the effects of biodiesel blended fuel on the engine combustion and emission characteristics in a four cylinder CRDI(Common-rail direct injection) diesel engine. In this work, the biodiesel-diesel blended fuel(20% of biodiesel and 80% of ULSD(ultra low sulfur diesel) by volume ratio, BD20) and ULSD fuel are used under the various injection pressures and engine speeds. The experimental results of BD20 and ULSD fuel show that NOx emissions were increased and soot emissions were decreased with the increase of injection pressure. In particular, NOx emissions were slightly increased for the BD20 fuel, however, soot emissions were significantly reduced compared to the ULSD fuel. When the engine speed is increased from 1000rpm to 2000rpm, NOx emissions are decreased at all tested conditions, and soot emissions are largely increased at lower injection pressure.