• Journal of the Korean earth science society
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• v.40 no.6
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• pp.549-560
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• 2019

The effects of the coal-fired power plant emissions, as the biggest point source of air pollutants, on spatiotemporal surface air pollution over the remote area are investigated in this study, based on a set of date selection and statistical technique to consider meteorological and geographical effects in the emission-concentration (source-receptor) relationship. We here proposed the sophisticated technique of data processing to separate and quantify the effects. The data technique comprises a set of data selection and statistical analysis procedure that include data selection criteria depending on meteorological conditions and statistical methods such as Kolmogorov-Zurbenko filter (K-Z filter) and empirical orthogonal function (EOF) analysis. The data selection procedure is important for filtering measurement data to consider the meteorological and geographical effects on the emission-concentration relationship. Together with meteorological data from the new high resolution ECMWF reanalysis 5 (ERA5) and the Korea Meteorological Administration automated surface observing system, air pollutant emission data from the telemonitoring system (TMS) of Dangjin and Taean power plants as well as spatio-temporal air pollutant concentrations from the air quality monitoring system are used for 4 years period of 2014-2017. Since all the data used in this study have the temporal resolution of 1 hour, the first EOF mode of spatio-temporal changes in air pollutant concentrations over the Seoul metropolitan area (SMA) due to power plant emission have been analyzed to explain over 97% of total variability under favorable meteorological conditions. It is concluded that SO₂, NO₂, and PM₁₀ concentrations over the SMA would be decreased by 0.468, 1.050 ppb, and 2.045 ㎍ m^-3 respectively if SO₂, NO₂, and TSP emissions from Dangjin power plant were reduced by 10%. In the same way, the 10% emission reduction in Taean power plant emissions would cause SO₂, NO₂, and PM₁₀ decreased by 0.284, 0.842 ppb, and 1.230 ㎍ m^-3 over the SMA respectively. Emissions from Dangjin power plant affect air pollution over the SMA in higher amount, but with lower R value, than those of Taean under the same meteorological condition.

• Korean Chemical Engineering Research
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• v.50 no.2
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• pp.365-370
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• 2012

In this study, Economic analysis of supercritical coal-fired power plant with $CO_2$ capture process was performed. For this purpose, chemical absorption method using amine solvent, which is commercially available and most suitable for existing thermal power plant, was studied. For the evaluation of the economic analysis of coal-fired power plant with post-combustion $CO_2$ capture process in Korea, energy penalty after $CO_2$ capture was calculated using the power equivalent factor suggested by Bolland et al. And the overnight cost of power plant (or cost of plant construction) and the operation cost reported by the IEA (International Energy Agency) were used. Based on chemical absorption method using a amine solvent and 3.31 GJ/$tonCO_2$ as a regeneration energy in the stripper, the net power efficiency was reduced from 41.0% (without $CO_2$ capture) to 31.6% (with $CO_2$ capture) and the levelized cost of electricity was increased from 45.5 USD/MWh (Reference case, without $CO_2$ capture) to 73.9 USD/MWh (With $CO_2$ capture) and the cost of $CO_2$ avoided was estimated as 41.3 USD/$tonCO_2$.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.40 no.7
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• pp.679-683
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• 2016

Boilers of large-sized coal-fired power plants are being operated under very poor conditions such as continuous operation or repeating of start-up and shutdown for a stable supply of electricity. Thus periodic inspection and maintenance are required to ensure reliability of operation. The loads of existing scaffolding systems for the maintenance of boilers are concentrated in the lower parts structurally, which may cause a serial collapse of the overall scaffolding system when there are problems in some members. Therefore, in this study, a safe furnace scaffolding system is developed by dispersing the loads in the upper part, as well as minimizing the hazards of serial collapsing. In addition, for cases where the direct installation of furnace scaffolding is challenging owing to the structure of the boiler tube, a lifting system for the installation of furnace scaffolding is developed so that furnace scaffolding can be supported to secure the integrity of the power generating facility.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2014.11a
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• pp.204-206
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• 2014

석탄 화력발전소에는 연소가스의 질소산화물(NOx) 저감을 위한 SCR(selective catalytic reduction)설비가 운전되고 있으며, SCR은 환원제인 암모니아($NH_3$)를 이용하여 연소가스 내에 질소산화물을 물과 질소로 분해하는 역할을 한다. 그러나, 연소가스 중의 일부 삼산화황($SO_3$)과 미반응 암모니아가 결합하여 황산암모늄염(Ammonium bisulfate; $NH_4HSO_4$)을 생성하며, 이는 후단 APH(air preheater)의 열소자에 점착된 후 분진들과 함께 성장하여 막힘을 야기한다. 막힘이 발생된 APH는 연소가스의 흐름을 방해하기 때문에 차압을 증가시키며, 이는 발전효율의 감소뿐만 아니라 급전정지를 초래한다. 이를 해결하기 위하여 $CO_2$ 드라이아이스 세정 방법을 적용하였으며, pilot-scale plant에서 실험을 수행하였다. 또한, 드라이아이스 공정변수인 분사압력과 분사시간을 제어하여 pilot-scale plant의 APH 열소자 표면에 생성되어있는 오염물질들의 제거효율을 관찰한 결과 95 %의 높은 제거효율을 보였다.

• Journal of Environmental Science International
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• v.18 no.7
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• pp.755-765
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• 2009

Some sections of the exhaust system to determine the shape of the duct is to suffer the difficulties by space constraints to install new equipment of the environment post-treatment for existing operation of the power plants. In this paper the large duct in flue gas desulfurization equipments of the 500MW coal-fired power plant on the current operation is numerically analyzed from induced draft fan exit to booster up fan inlet section which is in the narrow space of the exhaust system with four times bending and is connected to emergency duct to bypass the exhaust gas on the emergency operation. The procedure and method using computational fluid dynamics are proposed to maintain the stability of the guide vane with the uniform flow and a minimum pressure loss of exhaust gas in the case of normal and emergency operation between the direction of the flow of exhaust gas duct at different.

• Journal of Welding and Joining
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• v.30 no.6
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• pp.10-14
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• 2012

Recently the low alloy steel plate made with manganese-molybdenum is used widely in steam drum and separator of the new coal-fired power plant boiler. This material is suitable for the vapor storage of high pressure and high temperature. The high temperature creep strength of Mn-Mo alloy is higher than the carbon plate(SA516) that used in the subcritical pressure boiler. It reduces the thickness of the pressure vessel and makes the lightweight possible. Recently in the power plant boiler operation and production process, the damage has happened frequently in the heat affected zone and base material according to the hydrogen crack and delayed crack. This paper describes the research result about the damage case experienced in the boiler steam drum production process and present the optimum manufacture method for the similar damage prevention of recurrence.

• Journal of Korean Society of Environmental Engineers
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• v.36 no.2
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• pp.103-108
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• 2014

Using dried sludge as a secondary fuel of a coal-fired power plant is proposed as an alternative option for sludge disposal. Because elemental contents of sludge are different from those of coal, different levels of acidic gas emissions are expected from the co-combustion of sludge with coal. In this study, sludge samples were obtained from 7 sewage treatment plants in Korea. Each sludge sample was combusted together with coal in a lab-scale combustor, and the concentrations of nitrogen oxides ($NO_x$), sulfur dioxide ($SO_2$), hydrogen chloride (HCl), chlorine ($Cl_2$) in the flue gas were analyzed. Compared to the combustion of coal only, $NO_x$ concentration was slightly higher in the flue gas from the co-combustion of coal and sludge. $SO_2$ emission increased with the combustion of sludge due to the higher content of sulfur in sludge than in coal. For most of the tested samples, the concentrations of HCl and $Cl_2$ were varied depending on the chlorine content in the sludge sample.

• Proceedings of the KSME Conference
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• 2001.06d
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• pp.939-944
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• 2001

For the application of simultaneous $DeSO_{2}\;&\;DeNO_{x}$ equipment using non-thermal plasma process to the industrial and power plants, the many types of plasma device and process were studied. The e-beam and pulsed plasma corona discharge process are outstanding for the study to apply commercial large-scale plant from among these. In this paper, non-thermal plasma of technical trends and the characteristics of system developed by Doosan heavy industries & construction Co., Ltd. are explained. We have researched pulsed plasma corona discharge process since 1994. At the basis of reasonable results for the pilot plant, we constructed the demonstration plant at a domestic coal-fired power plant in 1999, as the previous step for commercial use. In near future, enough information about designs and costs of commercial-size system will be obtained.

• Journal of Welding and Joining
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• v.28 no.1
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• pp.41-46
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• 2010

The low alloy-steel material(1.0Cr-0.5Mo, SA213T12), which has widely been used for the waterwall tube in the conventional power plant, do not have enough creep rupture strength for waterwall tubes of the Ultra-supercritical(USC) boilers. According to this reason, the high-strength low alloy-steel(2.25Cr-1.0Mo, SA213T22) has newly been adopted for the waterwall tube in the USC boilers. This paper presents failure analysis on weld-joint of the waterwall tubes in USC boilers. Visual inspections were performed to find out the characteristics of the fracture. Additionally both microscopic characteristics and hardness test were carried out on failed tube samples. Failures seem to happen mainly because the welding process has not been conducted strictly.(preheating, P.W.H.T and so forth). Thus, this paper has the purpose to describe the main cause of the poor welding process and to explain how to prevent similar failures in those weld-joints.

• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.1842-1843
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• 2011

화력발전소는 화석연료 에너지를 전기에너지로 변환하는 과정에 참여하는 많은 종류의 기기들이 유기적으로 운전되는 복합시스템이다. 발전소 정상운전 중 어느 한 기기가 갑자기 정지되면, 불안정현상이 크게 발생하고 정상 운전이 어렵게 된다. 그러므로 이러한 상황이 발생하는 경우 빠른 시간 내에 적정한 수준으로 출력을 감소시키고, 새로운 안정운전 상태를 찾아가도록 하는 선행적 제어기능이 필요하게 된다. 화력발전소에 이 목적으로 구현되는 제어기능을 로드런백(Load Runback)이라고 부른다. 특히 화력발전소 보일러는 급수, 연료, 통풍을 담당하는 많은 기기가 많이 동시 운전되고 있으므로, 적합하게 설계된 로드런백 기능이 없다면 신뢰성 운전을 보장하기 어렵다. 이 논문에서는 국내 500MW급 표준화력에서 사용하고 있는 로드런백 기능의 핵심을 분석하였고, 이 분석을 토대로 현재 개발 단계에 국산화 제어시스템에 로드런백 기능을 구현하고자 한다. 실제 발전소 취득한 로드런백 시험 그래프를 제시하고 분석 결과의 타당성을 확인하였다.