• Applied Chemistry for Engineering
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• v.24 no.3
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• pp.253-259
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• 2013

In the present study, the characteristics of combustion phenomena and NOx emission in the OFA-type tangentially injected coal-fired boiler have been investigated numerically in order to find the effect of geometrical variation on the performance of the boiler. For these, numerical analyses of turbulent flow, chemical reaction, and radiation heat transfer are performed by using the computational fluid dynamics method. The predicted results clearly show that NOx formation highly depends on the combustion processes, the temperature and species concentrations. In addition, the optimum conditions for both the maximum NOx reduction and highest boiler efficiency can be obtained by considering the amount of supplied air and the injection angle at OFA, and modifying the boiler configuration. It is also found that the variation of supplied air at OFA is more effective than that of the injection angle for reducing the NOx emission, within the present operating conditions.

• Proceedings of the KSME Conference
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• 2001.06d
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• pp.967-972
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• 2001

The emission of $NO_{x}$ during coal combustion is a major reason of environment impact. $NO_{x}$ is an acid rain precursor and participates in the generation of smog through ozone production. $NO_{x}$ can be divided into thermal $NO_{x}$, fuel $NO_{x}$ and prompt $NO_{x}$. Thermal $NO_{x}$ is formed in a highly temperature condition dependent. Fuel $NO_{x}$ is dependent on the local combustion characteristics and initial concentration of nitrogen bound compound, while prompt $NO_{x}$ is formed in a significant quantity in some combustion environments, such as low temperature and short residence times. This paper presents numerical simulation of the flow and combustion characteristics in the furnace of a tangential firing boiler of 500MW with burners installed at the every comer of the furnace. The purpose of this paper is to investigate the reduction of $NO_{x}$ emission in a 500MW pulverized coal tangential firing boiler with different OFA's and burner angles. Calculations with different air flow rates of over fired air(OFA) and burner angles are performed.

• Plant Journal
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• v.13 no.2
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• pp.46-51
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• 2017

In this study, the boiler efficiency and the change of boiler combustion state with the burner operation of the uppermost layer of 870MW opposite fired coal boiler were measured. Test results showed that the boiler efficiency was high in the order of the uppermost layer simultaneous operation of the front and rear burners, the front burner, and the rear burner operation. When the front and rear burners were operated simultaneously, the heat absorption rate of water walls in the boiler furnace was uniform at four side, and the temperature deviation of the left and right steam on the convection front surface decreased. As the heat absorption rate of the boiler improved, the loss of boiler exhaust gas decreased and the coal supply amount decreased by 8 tons/hour compared to the operation of the rear burner. This will contribute not only to the reduction of fuel cost but also to the reduction of greenhouse gas emissions.

• Journal of Energy Engineering
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• v.14 no.2 s.42
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• pp.147-152
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• 2005

Calculation equations of fired fuel comsumption rating at boiler can lead from combustion anal-ysis and boiler heat balance using mass & energy conservations. By comparing calculation equation results with those of measurement, we can confirm the deviation of fuel consumption rate, and correction rate, and correction degree, and can also establish the proven technology to apply the equation at the site. We applied fuel rate equation to the operating power plant and recorded $2.4\%\;&\;1.5\%$ of deviation at each coal and oil fired boilers. This range of deviation is regarded as trustable to apply the fuel consumption equation to the actual site.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2009.10a
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• pp.533-534
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• 2009

• Journal of the Korean Professional Engineers Association
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• v.46 no.2
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• pp.44-50
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• 2013

The treatment of city life wastes is headache problem. Now, only small portion of burnable wastes is burnt at modern process incinerators, the other large portion is buried in the soil by landfill method. The burnable wastes will be increased year by year. The dioxin, the cancer-causing agent, produced by incineration of wastes influences harmful effect to national human health. The new idea of burnable wastes treatment is using the city life wastes as auxiliary fuel of fluidizing bed combustion boiler of large scale coal-fired power plant. The dioxin-free treatment of burnable wastes is sucessfully achieved by burning the wastes, in flyash storm at fluidizing bed combustion boiler.

• 한국연소학회:학술대회논문집
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• 2013.06a
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• pp.87-90
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• 2013

In pulverized coal fired boilers, slagging and fouling may cause significant effect on the operational life of boiler. As increasing a consumption of low rank coal, slagging and fouling are main issues in pulverized coal combustion. This study predicts ash deposition propensity in a 0.7 MW pilot-scale furnace. Slagging model is employed as a User-Defined Function (UDF) of FLUENT and validated against measurement and prediction. The results show good agreement compared with experiment. There is need to development of a pulverized coal combustion and slagging analysis at low coal.

• Asian Journal of Atmospheric Environment
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• v.6 no.1
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• pp.67-72
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• 2012

The chemical characterization of water-soluble organic carbon in ash emitted from a coal combustion boiler has not been reported yet. A total of 5 ash samples were collected from the outlet of an electrostatic precipitator in a commercial 500 MW coal-fired power plant, with their chemical characteristics investigated. XAD7HP resin was used to quantify the hydrophilic and hydrophobic water-soluble organic carbons (WSOC), which are the fractions of WSOC that penetrate and remain on the resin column, respectively. Calibration results indicate that the hydrophilic fraction includes aliphatic dicarboxylic acids and carbonyls (<4 carbons), amines and saccharides, while the hydrophobic fraction includes aliphatic dicarboxylic acids (>4-5 carbons), phenols, aromatic acids, cyclic acid and humic acid. The average mass of the WSOC in the ash samples was found to depend on the bituminous coal type being burned, and ranged from 163 to 259 ${\mu}g$ C/g of ash, which corresponds to 59-96 mg C of WSOC/kg of coal combusted. The WSOC mass accounted for 0.02-0.03 wt% of the used ash sample mass. Based on the flow rate of flue gas produced from the combustion of the blended coals in the 500 MW coal combustion boiler, it was estimated that the WSOC particles were emitted to the atmosphere at flow rates of 4.6-7.2 g C/hr. The results also indicated that the hydrophilic WSOC fraction in the coal burned accounted for 64-82% of the total WSOC, which was 2-4 times greater than the mass of the hydrophobic WSOC fraction.

• Journal of Energy Engineering
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• v.11 no.1
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• pp.67-73
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• 2002

The carbon-in-ash system for simultaneously monitoring the unburned carbon in fly ash produced in a coal-fired power plan is designed and evaluated using the domestic fly ash produced in the coal-fired power plant. Real time monitoring is very important to control the combustion of the boiler in the coal-fired power plant and the purification system for fly ash recycling. The carbon-in-ash system based on the capacitance measurement consists of a LCR meter, a duct collector and an electrode cell. The capacitance of fly ash increases linearly with increasing fly ash carbon contents. The water content in fly ash plays an important role on the ash capacitance. The empirical equation for predicting the content of unburned carbon in fly ash produced in the domestic Boryung, Hadong and Samchenpo coal-fired power plants can be derived in the range of carbon content 0-20%.

• Plant Journal
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• v.14 no.2
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• pp.39-44
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• 2018

In this study, I analyzed the effects on stabilizing the draft system, boiler efficiency when changing excess air ratio under 870 MW load limit operation condition in a large capacity coal fired power plant and decided optimum excess air ratio. It is positively necessary to choose adequate excess air ratio for stabilizing draft system because air pre-heater pressure drop and induced draft fan first stall margin are changing when adjusting excess air ratio. This study therefore, measured air pre-heater pressure drop, induced draft fan first stall margin, boiler efficiency, loss and has chosen adequate excess air ratio adjusting excess air ratio from 1.153 to 1.127. So it is recommended that the operation point needs to be changed to 1.127 that is not only to decrease air pre-heater pressure drop and to stabilize draft system and to secure stall margin but also to maintain boiler efficiency to equivalent level.