• Journal of Korean Society for Atmospheric Environment
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• v.24 no.6
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• pp.662-673
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• 2008

Two hybrid receptor models, potential source contribution function (PSCF) and concentration weighted tracjectory (CWT), were compared for locating $PM_{2.5}$ sources contributing to the atmospheric $PM_{2.5}$ concentrations in Seoul. The source contribution estimates by chemical receptor model (CMB) receptor model were used to identify better source areas, Among the sources, soil, agricultural burning, marine aerosol, coal-fired power plant and Chinese aerosol were only considered for the study because these sources were more likely to be associated with the long-range transport of air pollutant. Both methods are based on combining chemical data with calculated air parcel backward trajectories. However, the PSCF analyses were performed with trajectories above the $75^{th}$ percentile criterion values, while the CWT analyses used all trajectories. This difference resulted in locating of different sources, which might be helpful to interpret locating of $PM_{2.5}$ sources, High possible source areas in source contribution of soil and agricultural burning contributing to the Seoul $PM_{2.5}$ were inland areas of Heibei and Shandong provinces (highest density areas of agricultural production and population) in China. The "Chinese aerosol" was used as a representative source for the $PM_{2.5}$ originated from urban area in China. High possible source areas for the aerosol were the cities in China where are relatively close to the receptor. This result suggests that Chinese aerosol is likely to be a useful tool in studies on source apportionment and identification in Korea.

• Journal of the Korean Ceramic Society
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• v.39 no.8
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• pp.735-741
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• 2002

This paper investigates circularity of fly ashes using the digital image processing. Fly ashes directly collect from electrostatic precipitator when the load of conditions of boiler are changed at a coal-fired power plant. Circularity measurement can be accomplished in five steps: ① image acquisition, ② grey image processing, ③ detection the component to measure ④ binary image processing ⑤ feature measurement. The mean circularity of fly ashes is in the range of 0.78 to 0.83. fly ashes collected from the same hopper has similar circularity regardless of the load of boiler and circularity increases as going from the 1st hopper to 3rd one, namely as particle size become finer.

• Journal of the Korean Ceramic Society
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• v.40 no.7
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• pp.702-708
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• 2003

Cement paste, mortar or concrete specimens, substituting the content of Portland cement with fly ash up to 50 wt%, were prepared to investigate the effect of fly ash on the temperature, free lime content and strength etc. of mortar/concrete. Being compared with the concrete made of ordinary Portland cement, temperature increment of the concrete containing 50 wt% fly ash reduced, according to appropriate conversion formulae, to about 45％ at the 7 days curing time: the temperature increment of the former amounted to 33.4$^{\circ}C$, while that of the latter only to 18.7$^{\circ}C$. On the other hand, it is better to control the content of fly ash in the cement that is used for reinforced concrete not to exceed 30 wt％. In this study, more than 28 days curing time is necessary in order that the strength of concrete made of fly ash cement will be higher than that of pure Portland cement. In addition, 28-days concrete strength higher than 360 kg/$\textrm{cm}^2$ could be easily achieved even with 50 wt% fly ash cement.

• Asian Journal of Atmospheric Environment
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• v.11 no.1
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• pp.33-36
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• 2017

China is suffering from severe air pollution especially fine $PM_{2.5}$ pollution. In 2015, the annual average $PM_{2.5}$ concentration of the 338 municipal cities was $50{\mu}g/m^3$, 78% cities at or above the prefectural level failed to comply with the $PM_{2.5}$ concentration standards. The $13^{th}$ Five-Year Plan for National Economic and Social Development set the goal that the annual average concentration of $PM_{2.5}$ in the municipal cities which failed to attain the ambient air quality standards shall be decreased by 18% by 2020 (CCCPC, 2016). In this study, an air pollution control scenario during the $13^{th}$ Five-Year Plan period was proposed and the $SO_2$, $NO_x$ and PM emission reductions in response to different measures in 31 provincial-level regions mainland China by 2020 were estimated. The air quality in the target year (2020) was simulated using the WRF-CMAQ model. The results showed that by 2020, the emissions of $SO_2$, $NO_x$ and primary PM in mainland China will be reduced by 4.19 million tons, 3.94 million tons and 4.41 million tons, a drop of 23%, 21% and 25% respectively compared with that in 2015, and the annual average concentration of $PM_{2.5}$ will decrease by 19%. Coal-fired power plant contributes the most pollutant emission reduction.

• Clean Technology
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• v.19 no.4
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• pp.453-458
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• 2013

Fly ash has capacity to oxidize or adsorb mercury in a flue gas. Mercury oxidation and adsorption efficiencies of fly ash vary depending on the properties of fly ash. This study was designed to understand reaction characteristics of mercury with fly ash components. The fly ash components were tested to determine their oxidation and adsorption capabilities for elemental mercury and oxidized mercury. A sample was synthesized with fly ash components and tested. The test results were compared with those of the fly ash sample obtained from a coal-fired power plant. $Fe_2O_3$, CuO and carbon black showed higher oxidation or adsorption efficiency for elemental mercury while CaO, MgO, CuO and carbon black showed higher adsorption efficiency for mercury chloride. In addition, the synthesized sample showed comparable mercury oxidation and adsorption efficiencies to the fly ash sample.

• Resources Recycling
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• v.26 no.6
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• pp.10-19
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• 2017

It is studied the effect of crystal structure of domestic High-Ca limestones using absorbent for desulfurization on the grinding characteristics and dissolution rates in wet flue gas desulfurization process of domestic coal fired power plant. It compared the crystal structure, grinding work index and dissolution rates with 4 Limestones from Jecheon-Danyang with different crystal structure, and we found that grinding work index differ in crystal size and crystal structure of limestones : The lower the value of the grinding work index is, the higher the dissolution rates of limestones. Confirmed that we have important indicators of grinding characteristics for crystal structure with CaO content of limestones.

• Journal of the Korean GEO-environmental Society
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• v.11 no.6
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• pp.77-83
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• 2010

In this study, we tried to determine any detrimental effects on water quality when bottom ash obtained from a coal-fired power plant intended to be used as a fill material in construction sites. Physical-chemical properties of bottom ash were determined using proximate analysis, elemental analysis, XRD, and XRF. Classification of bottom ash as a waste material and soil contamination due to the use of bottom ash were performed by Korea waste standard leaching test and soil toxicity test, respectively. Results of leaching tests were compared to the regulations for water quality and groundwater quality and no harmful effects on water quality were found. Most of heavy metals in leachate were below detection limits but trace amount of $Cr^{6+}$ was found. However, concentration of $Cr^{6+}$ was below the regulation criteria. Column leaching tests indicated that concentrations of Pb and Zn were slightly higher than regulations but below regulations within 1 PVE, but concentrations of sulfate were 10 times higher than regulation and thus, the required time to reach regulation was almost 8 PVE.

• Journal of Energy Engineering
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• v.28 no.1
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• pp.1-9
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• 2019

In the flue gas desulfurization process of the coal-fired power plant, the grinding efficiencies of the limestone as the sorbent for desulfurization were compared after BWI and HGI measurements. As a result, the grinding index of the domestic desulfurization limestone were linear inversely proportional relationship with decreasing BWI was observed with increasing HGI. There was a difference in grinding efficiency depending on the chemical composition and crystal structure. Therefore, it is considered that when grinding ability of limestone is measured, the grinding property of the sample can be confirmed even by using HGI which can be measured more easily than BWI which is difficult to measure and takes a long time. The desulfurization efficiency can be improved by selective utilization of limestone depending on the crushing characteristics.

• Environmental and Resource Economics Review
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• v.31 no.3
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• pp.343-365
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• 2022

This paper tries to identify the effect of reducing PM2.5 concentration of the First Seasonal Management Policy implemented by Korean government by using statistical method. In particular, this paper tests the hypothesis that this policy effect may differ by region (west-coast, south-coast, and east-coast). To this end, this paper analyzed only pure policy effects by removing temporal abnormalities such as COVID-19, warm winter temperature during the policy implementation period (December 2019 to March 2020) by using the difference-in-difference method (DID). As a result of the analysis, this policy had the effect of reducing PM2.5, but the effect is not homogenous by region. In particular, PM2.5 reducing effect is the largest in west-coast region and south-coast region folllows, but its effect is not statistically significant in the east-cost region. In conclusion, this paper drew implications that the current Seasonal mamangement policy which is implemented regardless of the regional difference needs to be changed.

• Environmental and Resource Economics Review
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• v.27 no.2
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• pp.261-286
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• 2018

This paper evaluated the economic feasibility of the life extension of Kori unit 1 and Wolsong unit 1 according to the types of the nuclear power plants (NPPs) and the life extension period comparing to the levelized costs of energy (LCOE) of the new NPPs, coal-fired plants (CFPs), and combined cycle gas turbine (CCGTs) which proposed in the $7^{th}$ Basic Plan for Electricity Supply and Demand. The economic feasibility of the life extension of NPPs using LCOE method is affected by the types of NPPs, lifetime extension periods, discount rate, and capacity factor. According to the analysis results, the pressurized light water reactor (PWR) is more economical than the pressurized heavy water reactor (PHWR). Comparing the economical efficiency between the life extension of NPPs and other alternatives, the operation of the PWR for 20 years is more economical than the one of new NPPs and CFPs. However, 20 years of life extension of PHWR is more economical than the CCGTs, but less economical than new NPPs and CFPs. In summary, the 20 years of life extension of the NPPs seems to be more, especially for the PWR, which is more cost effective than other generation alternatives. Therefore, the government policy of the life extension of NPPs need to be a selective approach that simultaneously considers both safety and economics rather than closing all NPPs.