• 한국연소학회:학술대회논문집
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• 2004.11a
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• pp.175-180
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• 2004

Improving furnace efficiency is a high priority need for aluminum, glass, steel and other metal casting industries. Oxy-fuel combustion is considered to be one of the most effective method to improve thermal efficiency and reduce $NO_x$, SOx and $CO_2$ emissions for high temperature furnaces. The characteristics of an oxy-fuel flame, in particular its shape, radiation profile and exhaust gas composition are considerably different to those of an air-fuel burner. For this reason, a new approach is needed regarding factors such as burner design, power input levels, number and positioning strategies of burners and also control philosophies. In this paper will discuss the latest developments of high performance oxy-fuel combustion reheating furnace system. This high performance oxy-fuel combustion system will be shown to be technologically superior to other types of combustion systems in the areas of fuel efficiency, emissions and productivity.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.29 no.7 s.238
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• pp.861-867
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• 2005

In order to develop oxy-fuel combustor, the Flame length characteristic of $CH_4$ with oxidizer of air and oxygen has been experimentally investigated for tile nozzle diameters of 1.6mm, 2.7mm, 4.4mm and 7.7mm. The structure of $CH_4$ flame with oxidizer of oxygen was sharp in contrast with the $CH_4$ flame with oxidizer of air. The stability of $CH_4$ flame with oxidizer of oxygen was higher than $CH_4$ flame with oxidizer of air. In all $CH_4$ flames with oxidizer of air and oxygen, the flame length were dependent on the flowrate in laminar flame regime, and in turbulent flame dependent on the initial jet diameter. Using correlation equation of Delichatsios, the flame length has been expected exactly for $CH_4$ flame with oxidizer of air, but underestimated for $CH_4$ flame with oxidizer of oxygen. This paper proposed correlation equation of $CH_4$ flame with oxidizer of oxygen.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.40 no.9
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• pp.577-587
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• 2016

Although the formation of oxy-fuel MILD combustion is considered one of the promising combustion technologies for high thermal efficiency, low emissions and stability have been reported as difficulties. In this paper, the effect of combustor geometry and operating conditions on the formation of oxy-fuel MILD combustion was analyzed using numerical simulation. The results show that the high temperature region and average temperature decreased due to an increase in oxygen inlet velocity; moreover, a high degree of temperature uniformity was achieved using an optimized combination of fuels and an oxygen injection configuration without external oxygen preheating. In particular, the oxy-fuel MILD combustion flame was found to be very stable with a combustion flame region at equivalence ratio 0.90, fuel velocity 10 m/s, oxygen velocity 200 m/s, and nozzle distance 33.5 mm.

• Journal of the Korean Society of Combustion
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• v.21 no.4
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• pp.39-47
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• 2016

The aims of this research were to investigate combustion characteristics of lab-scale pressurized oxy-fuel combustion(POFC) system. In this study, the reactor, 800 mm long, was equipped with co-axial burner. Low calorific value syngas that is composed of mainly CO and $H_2$ was used as fuel whereas pure oxygen was used as an oxidant. Thermal heat input to the reactor varied from 2.6 kW to 6.1 kW. The reactor pressure also increases from atmospheric up to 15 bar. The results show that as the pressure increase, the temperature of reactor decreases on the whole in all cases. A significant temperature drop was observed especially at the bottom section of the reactor that exist flame. In addition, the flame instability increases as the pressure increases. Furthermore $NO_x$ emissions increases from atmospheric up to 2 bar. However beyond 2 bar, $NO_x$ emission reduces as pressure increases. Lastly $NO_2$ ratio in $NO_x$ also increases as pressure increases.

• 한국연소학회:학술대회논문집
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• 2012.04a
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• pp.43-46
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• 2012

The oxygen concentration of primary oxidizer is decided under 10% due to flammable risk. It can be a spontaneous combustion inside burner or tube if the excess oxygen is added to primary oxidizer in Oxy-PC burner. In this case, the rest oxygen which can not be injected to primary oxidizer should be injected to another port. If added it to a second oxidizer, the ignition is unstable at outlet of burner. Accordingly an extra lancing port is needed to insert into the burner unlike other common air mode. And the flame formation and combustion characteristic differ from lancing port position. Therefore we observed flame formation which has stable combustion characteristic according to the shape and position of lancing port.

• Proceedings of the SAREK Conference
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• 2008.06a
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• pp.1019-1024
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• 2008

A 3 MW class oxy-fuel boiler has been developed to capture $CO_2$ from the exhaust gas. The system is a scale-up of the previous 0.5 MW class system in general. A heat exchanger and a mixer are additionally installed to stabilize the flame for the FGR mode. The system yields the exhaust gas with $CO_2$ concentration over 90% and reduced NO emission to 1/10 of conventional air combustion system.

• 한국연소학회:학술대회논문집
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• 2006.04a
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• pp.149-156
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• 2006

Structure of edge flame established in a mixing layer, formed between two uniformly flowing pure $CH_4$ and pure $O_2$ streams, is numerically investigated by employing a detailed methane-oxidation mechanism. The numerical results exhibited the most outstanding distinction of using pure oxygen in the fuel-rich premixed-flame front, through which the carbon-containing compound is found to leak mainly in the form of CO instead of HC compounds, contrary to the rich $CH_4-air$ premixed flames in which $CH_4$ as well as $C_2H_m$ leakage can occur. Moreover, while passing through the rich premixed flame, a major route for CO production, in addition to the direct $CH_4$ decomposition, is found to be $C_2H_m$ compound formation followed by their decomposition into CO. Beyond the rich premixed flame front, CO is further oxidized into $CO_2$ in a broad diffusion-flame-like reaction zone located around moderately fuel-rich side of the stoichiometric mixture by the OH radical from the fuel-lean premixed-flame front. Since the secondary CO production through $C_2H_m$ decomposition has a relatively strong reaction intensity, an additional heat-release branch appears and the resulting heat-release profile can no longer be seen as a tribrachial structure.

• Journal of the Korean Society of Combustion
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• v.11 no.1
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• pp.19-26
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• 2006

Structure of edge flame established in a mixing layer, formed between two uniformly flowing pure $CH_4$ and pure $O_2$ streams, is numerically investigated by employing a detailed methane-oxidation mechanism. The numerical results exhibited the most outstanding distinction of using pure oxygen in the fuel-rich premixed-flame front, through which the carbon-containing compound is found to leak mainly in the form of CO instead of HC compounds, contrary to the rich $CH_4-air$ premixed flames in which $CH_4$ as well as $C_2H_m$ leakage can occur. Moreover, while passing through the rich premixed flame, a major route for CO production, in addition to the direct $CH_4$ decomposition, is found to be $C_2H_m$ compound formation followed by their decomposition into CO. Beyond the rich premixed flame front, CO is further oxidized into $CO_2$ in a broad diffusion-flame-like reaction zone located around moderately fuel-rich side of the stoichiometric mixture by the OH radical from the fuel-lean premixed-flame front. Since the secondary CO production through $C_2H_m$ decomposition has a relatively strong reaction intensity, an additional heat-release branch appears and the resulting heat-release profile can no longer be seen as a tribrachial structure.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.29 no.11 s.242
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• pp.1277-1284
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• 2005

The combustion characteristics of methane oxygen diffusion flames have been investigated to give basic information for designing industrial oxyfuel combustors. NOx reduction has become one of the most determining factors in the combustor design since the small amount of nitrogen is included from the current low cost oxygen production process. Flame lengths decreased with increasing fuel or oxygen velocity because of the enhancement of mixing effect. Correlation equation between flame length and turbulent kinetic energy was proposed. NOx concentration was reduced with increasing fuel or oxygen velocity because of the enhanced entrainment of the product gas into flame zone as well as the reduction of residence time in combustion zone.

• 한국연소학회:학술대회논문집
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• 2002.11a
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• pp.57-64
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• 2002

This paper describes the results of a series of experiments executed by using two pilot-scale oxv-fuel burners are designed for maximum capacity of 50,000 kacl/hr, 300,000 kcal/hr and installed in the test furnace. The effects of turn-down ratio, excess oxygen ratio, nozzle exit velocity, injection angle, swirl vane angle and inlet oxygen temperature on the combustion characteristic are investigated. Temperature distributions are measured using R-type and Molybdenum sheathed C-type thermocouple. The results showed that maximum temperature and mean temperature increase with the increase of turn-down ratio and inlet oxygen temperature. The maximum flame temperature was increased about 35% compared to the case of equivalent air operated condition. In addition, Optimum excess oxygen ratio and nozzle characteristics are obtained for this oxy-fuel glass melting furnace.