• Plant Journal
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• v.15 no.4
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• pp.30-35
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• 2019

To meet both increasing social demand for reduction of fine dust and the strengthened air pollutant emission standards, this paper indicated performance enhancement of FGD with structural constraints in 500 MW coal fired thermal power plant's. Through modifying internal facilities for flue gases to make swirl in the absorption tower, it made turbulence and increased the efficiency of material transfer, the reaction area and time with the limestone slurry. Therefore, it could reduce dust and enhance the performance of collecting the SO₂. As a result, desulfurization efficiency was improved from 91.61% to 98.43% and dust removal efficiency was improved from 77.4% to 87.08%. Emission density is 7.85 ppm of SO₂ and 4.67 mg/㎥ of dust. This is a level that satisfies emission limit of 25 ppm of SO₂ and 5 mg/㎥ of dust which are the air pollutant emission standards of 2023. The performance enhancement method of this study is expected to be effectively applied to other coal-fired power plants with similar constraints.

• Plant Journal
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• v.17 no.2
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• pp.32-41
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• 2021

Recently, air environmental issues such as fine dust have rapidly emerged as national issues, and intensive environmental regulations are being applied to coal-fired power plants. This study introduces the case of improving the performance of desulfurization facilities for removing sulfur oxides and dust, which are the main air pollutant emitters of coal-fired power plants, and conducted four case studies to improve the performance of 1,000 MW power plants currently in operation and carried out construction. Liquid ratio was increased by remodeling the absorption tower of desulfurization facilities, and vaporization reaction was promoted by increasing the flow rate of oxidized air. In addition, the gas heater leakage rate was improved to improve the efficiency of final desulfurization facilities. It is expected that performance improvement work considering harmony with existing facilities will satisfy the regulations(25ppm of sulfur oxides, 5mg/Sm³) that will be applied from 2023, and can be referred to other thermal power plants for review and application.

• Journal of the Korean Society of Combustion
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• v.19 no.3
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• pp.8-17
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• 2014

The aims of this research were to evaluate effects of biomass co-firing to pulverized coal power plants and the variation of co-firing ratios on the plant efficiency related to power consumption of auxiliary system and flue gas characteristics such as production and component by process simulation based on the existing pulverized coal power plant. In this study, four kinds of biomass are selected as renewable fuel candidates for co-firing: wood pellet(WP), palm kernel shell(PKS), empty fruit bunch(EFB) and walnut shell(WS). Process simulation for various biomass fuels and co-firing ratios was performed using a commercial software. Gas side including combustion system and flue gas treatment system was considering with combination of water and steam side which contains turbines, condenser, feed water heaters and pumps. As a result, walnut shell might be the most suitable as co-firing fuel among four biomass since when 10% of walnut shell was co-fired with 90% of coal on thermal basis, flue gas production and power consumption of auxiliary systems were the smallest than those of other biomass co-firing while net plant efficiency was relatively higher than those of other biomass co-firing. However, with increasing walnut shell co-firing ratios, boiler efficiency and net plant efficiency were expected to decrease rather than coal combustion without biomass co-firing.

• Journal of Korean Society of Environmental Engineers
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• v.28 no.10
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• pp.1065-1073
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• 2006

The unturned carbon in fly ash, recently occurred in the coal-fired Yong Hung power station, caused some problems in ash utilization and boiler efficiency. This paper describes the analysis of unburned carbon and six coals, some tests performed at Yong Hung Boiler, and the results of combustion modification for the reduction of unburned carbon in fly ash. From the physical and chemical analysis of unburned carbon in fly ash, most particles were turned out to be hollow cenosphere and agglomerated soot particles. The sooting potential from six coals used in the plant were investigated with CPD(Chemical Percolation Devolatilization) model. The results showed that the higher potential was presented to Peabody, Arthur, Shenhua coals rather than other coals. It was necessary to measure the coal flow rates at each coal feeding pipe for four burner levels since they affect the extent of mixing of soot with oxidant, in turn, the oxidation rate of soot particles. The unbalance in coal flow rate was found in several coal pipes. We successfully reduced unturned carbon in ash by increasing the excess air and changing the SOFA's yaw angle.

• Proceedings of the KIEE Conference
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• 1989.07a
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• pp.94-97
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• 1989

This work describes the imortance of the load run back control of a thermal power plant which has a serious effect on a power system, and shows the load run back tests results which was carried out at BORONG Thermal Power Plant, finally suggests what control circuits should be modified in the plant control system in order to prevent plant trip in case of auxiliary machine failure.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 2003.09a
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• pp.350-353
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• 2003

In this paper, we proposed the method to design fuzzy controller using the experience of the operating expert and experimental numeric data for the robust control about the noise and disturbance instead of the traditional PID controller for the main steam temperature control of the thermal power plant. The temperature of main steam temperature process has to be controlled uniformly for the stable electric power output. The process has the problem of the hunting for the cases of various disturbances. In that case, the manual action of the operator happened to be introduced in some cases. We adopted the TSK (Takagi-Sugeno-Kang) model as the fuzzy controller and designed the fuzzy rules using the informations extracted directly from the real plant and various operating condition to solve the above problems and to apply practically. We implemented the real fuzzy controller as the Function Block module in the DCS(Distributed Control System) and evaluated the feasibility through the experiment81 results of the simulation.

• Progress in Superconductivity and Cryogenics
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• v.23 no.3
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• pp.14-19
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• 2021

The reduction of carbon dioxide emissions becomes a global issue, the main source of carbon dioxide emissions in the Asian region is the energy conversion sector, especially coal-fired power plants. We are working to develop technologies that will at least limit the increase in carbon dioxide emissions from the thermal power plants as one way to reduce carbon dioxide emissions. Our research aims to reduce carbon dioxide emissions by removing iron oxide scale from the feedwater system of thermal power plants using a superconducting high-gradient magnetic separation (HGMS) system, thereby reducing the loss of power generation efficiency. In this paper, the background of thermal power plants in Asia is outlined, followed by a case study of the introduction of a chemical cleaning line at an actual thermal power plant in Japan, and the possibility of introducing it into the thermal power plants in China based on the results.

• Journal of Energy Engineering
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• v.26 no.4
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• pp.74-83
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• 2017

Coal-fired power plants supply roughly 50 percent of the nation's electricity but produce a disproportionate share of electric utility-related air pollution. Coal combustion technology can facilitate volume reduction of up to 90%, with the inorganic contaminants being captured in furnace bottom ash and fly ash residues. These disposal coal ash residues are however governed by the potential release of constituent contaminants into the environment. Accelerated carbonation process has been shown to have a potential for improving the chemical stability and leaching behavior of bottom ash residues. The aim of this work was to quantify the volume of $CO_2$ that could be sequestrated with a view to reducing greenhouse gas emissions and stabilize the contaminated heavy metals from bottom ash samples. In this study, we used PC boiler bottom ash, Kanvera reactor (KR) slag and calcined waste lime for measuring chemical analysis and heavy metals leaching tests were performed and also the formation of calcite resulting from accelerated carbonation process was investigated by thermo gravimetric and differential thermal analysis (TG/DTA).

• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.1304-1308
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• 2005

This paper presents the case that the existing analog control systems were retrofitted with digital DCS(Distributed Control System)s for boiler unit in thermal power plant. Replacement of existing worn-out or obsolete analog control systems has been considered. Replacement of existing analog control systems with another analog control systems has lots of difficulties in maintaining the systems due to being out of stock. Due to those difficulties, existing analog control systems have been retrofitted with digital DCSs in many industrial sites. KEPRI(Korea Electric Power Research Institute) accomplished the project that retrofitted analog control systems with the developed DCSs for boiler unit in middle-scale coal-fired thermal power plant. The benefits of an upgrade to digital control include a increase of reliability due to system redundancy, ease of modifying the control logic and the parameters of function block, ease of maintenance due to available spare parts, improvement of information display, ease of modifying MMI(Man Machine Interface) displays, a increase in system availability, and improvement of control performance. This paper describes how to use the parameters of existing analog controllers, the implementation of digital PID controller, control system configuration for boiler unit in thermal power plant, some boiler control loops, control result during commissioning, and the comparison of boiler characteristic test data after retrofitting with the existing test data.

• Plant Journal
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• v.18 no.1
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• pp.55-61
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• 2022

In this study, I analyzed the effect of slagging caused by blending bituminous coal and subbituminous coal while maintaining the generator output, combustion conditions, and ventilation conditions for 870MW thermal power plant designed with bituminous coal. Accordingly I proposed an acceptable method of blending coal method. the blending ratio of sub-bituminous coal was adjusted to 10%, 20%, 40%, 60%, 80%, etc. to confirm ultimate analysis, proximate analysis, ash fusion temperature change, slagging indices, etc. Proper blending coal conditions are blending with sub-bituminous coal at 40% or less, ratio of base component to acid component(B/A) is 0.4 or less or 1 or more, total alkali(TA) is 3.5 or less, fusion slagging index(Rfs) is 1,345℃ or more, and ash content is 13% or less in ultimate analysis, the ash content in proximate analysis is 15% or less, and the initial deformation temperature(IDT) should be at least 1,200℃ or more