• The Journal of Engineering Geology
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• v.15 no.2 s.42
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• pp.133-144
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• 2005

Stability investigations were conducted for the heap of coal associated wastes occurred from D mine located in Gang-Won Province from the geotechnical and environmental engineering aspect, and a countermeasure was also examined to increase the stability in this area. Quality of water flowed from the heap of coal associated wastes was identified as Am. Slope stability investigations were conducted with both circular failure analyses using SLOPILE program and planar failure analyses in cases of dry, rainy, and ordinary slopes. The results of circular failure analyses indicated that the factor of safety is 0.78 for rainy case. for planar failure analyses, the factor of safety decreases with increase the depth and reaches below 1 about 4m depth for rainy case. A retaining wall system with backfill using the recycled-concrete aggregates as a practical scheme was suggested to satisfy both demands: reducing Am generation, and enhancing slope stability in the deposits of coal associated wastes.

• Journal of Korean Society of Environmental Engineers
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• v.29 no.1
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• pp.47-53
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• 2007

The aim of this study is to research applicable possibility or Dry Sorbent Injection Technique(DSI) in sox removal process using Computational Fluid Dynamics(CFD) software package. It will be applied for 500MW in capacity coal-fired thermal power plant operated by South Korea N. Power Co., Ltd. The DSI process is adapted between a preheater and an EP process in the technological assembly. The numerical analysis performs in predicting and optimizing of DSI process's characteristics, which consists of structure of duct, position of injection nozzles, injection speed, and dispersion of sorbent. Computing results are shown that degree of sorbent dispersion depends on structure of duct and position of injection nozzles strongly. The highest dispersion efficiency was obtained when we set a Lobed-plate inside the duct and 6 injection nozzles on the duct(4 injection nozzles at the corners and 2 injection nozzles on upper and under walls as a rectangle duct shape). We also know that change of injection speed of sorbent doesn't have an large effect on the sorbent dispersion but it can effect to drop pressure.

• Economic and Environmental Geology
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• v.36 no.2
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• pp.111-121
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• 2003

The objective of this study is to investigate the physical and chemical properties for environmental assessment of water system affected by acid mine drainage (AMD) from coal mining activities in the Youngwol, Jungseon and Pyungchang areas in Korea. During November 2000 to July 2002, 6 times of water samples were collected season-ally from acid mine drainage and nearby streams at 13 coal mines in the study area. The physical and chemical properties including pH, Eh, TDS, salinity, bicarbonates and DO were measured in the field. Eighteen cations includ-ing Al, Ca, Fe, Mg, Mn and Zn, and 6 anions including nitrates and sulfates were also analyzed by ICP-AES and If, respectively. Acid water from the Jungam coal mine has typical characteristics of AMD with very low pH(3∼4) and high TDS(1,000∼5,000 mg/1). Relatively high concentrations(mg/kg) of heavy meals, especially for Al(380), Fe(80), Mn(44) and Zn(8), were found in water samples from the Jungam coal mine area. Water samples from the Seojin, Sebang and Sungjin coal mines also contained over 50 mg/l of Al, >100 mg/1 of Fe and )10 mg/1 of Mn. In addition to anioins, over 1,000 mg/l of sulfate was found in several water samples. Seasonally, the concentrations of metals and sulfates varied; wet season samples were relatively higher in metals and sulfates than dry season samples. It is needed to establish the proper remediation and environmental monitoring of the AMD continuously.

• Journal of Korean Society for Atmospheric Environment
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• v.10 no.3
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• pp.170-174
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• 1994

Atmospheric lead concentrations in Seoul were monitored for ten years from January 1984 to June 1993 using X-ray fluorescence Spectrometer. 342 aerosol samples were collected using high volume samplers at two sites : one at Chungang University campus from 1984 to 1988 and the other at Yonsei University campus from 1989 to 1993. Lead concentration increased steadily from about 300ng/㎥ to the maximum of about 600ng/㎥ in 1988 and then decreased, and this is similar to the pattern of Korean leaded gasoline sales implying that Korean automobile emission is the main source. However, the emission from nation's coal combustion appeared to be substantial as welt, and this emmision is the major cause for the secondary feature strong seasonal variability. Lead concentration varied systematically from season to season, low in summer and high in winter. The region's characteristic climate, frequent and heavy precipitations in summer and dry in winter is considered to be another cause for the seasonal variability.

• 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 Health Sciences
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• v.26 no.4
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• pp.38-44
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• 2000

Compared to other waste, waste tire has much discharge quantity and calorie. When we use waste heat from waste tire, it can be definitely better substitute energy than coal and anthracite in high oil price age. To use as a basic data for providing low cost and highly effective heating system, following conclusion was founded. Annual waste tire production was 19,596 million in 1999, Recycling ratio was almost 55% and more than 8.78 million was stored. Waste tire has lower than 1.5% sulfur contain ratio which is resource of an pollution, So it is a waste fuel which can be combustion based on current exhaust standard value without any extra SOx exclusion materials. Waste tire has 9,256Kcal/kg calorific value and it is higher than waste rubber, waste rubber, waste energy as same as B-C oil. When primary and second air quantity was 1.6, 8.0 Nm$^3$/min, dry gas production time was 270min and total combustion time was 360 min. In the SOx, NOx, HC of air pollution material density were lower than exhaust standard value at the back of cyclone and dusty than exhaust standard value without dust collector.

• Journal of the Korea Concrete Institute
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• v.27 no.5
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• pp.531-539
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• 2015

Properties of normal-strength mortar containing coarsely-crushed coal bottom ash considering standard particle size distribution of fine aggregate were investigated. Mortar containing raw bottom ash was applied as a reference. By crushing the bottom ash with a particle size larger than fine binder but smaller than fine aggregates, i.e., coarse-crushing, water absorption and specific gravity of the particles could be controlled as similar levels to those of natural fine aggregates. Workability and strength of the mortar were not changed and even increased when the coarsely-crushed bottom ash was added considering standard particle size distribution in Standard Specification for Concrete, while those were decreased when raw bottom ash was added without any treatment. When a replacement ratio of coarsely-crushed bottom ash was less than 30 vol.%, there were no significant decrease in dynamic modulus of elasticity and dry shrinkage of the mortar.

• Journal of Korean Society for Atmospheric Environment
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• v.18 no.2
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• pp.161-170
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• 2002

Total(=wet+dry) atmospheric depositions were collected by filtration-sampling method at 17 sampling sites of the coal-fired power plant area from September 1999 to January 2000. The soluble and insoluble fractions of deposition were also measured to investigate a suitability of simplified collection method for a long-term monitoring of total deposition. In the study, the 50% of sampled soluble fractions showed the electric conductivity (E.C.) of below 50 $\mu$S/cm and the 42% of them showed the lower pH than 5.0. The monthly mean fluxes of water soluble ionic components; S $O_4$$^{2-}$, C $l^{[-10]}$ , N $O_3$$^{[-10]}$ , N $a^{+}$, N $H_4$$^{+}$, $K^{+}$, $Mg^{2+}$, $Ca^{2+}$ were 168.4 kg/k $m^2$.month, 100.5 kg/k $m^2$.month, 88.6kg/k $m^2$.month, 31.3kg/k $m^2$.month, 25.6 kg/k $m^2$.month, 13.3 kg/k $m^2$.month, 8.7 kg/k $m^2$.month, 43.1kg/k $m^2$.month, respectively. The mean ionic concentration of all sample(n=79) was 314 $\mu$eq/ι, with contributions of 24.2% and 23.0% by [nss-C $a^{2+}$] and [nss-S $O_4$$^{2-}$]. The ratio of [N $O_3$$^{[-10]}$ ]/[nss-S $O_4$$^{2-}$] and [N $H_4$-C $a^{2+}$] were found to be 0.52 and 0.68, respectively.espectively.

• Journal of the Korea Institute of Building Construction
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• v.17 no.4
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• pp.313-320
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• 2017

Flue gas desulfurization gypsum(FDG) is produced when removing sulfur oxides from combustion gas generated by coal power plant. However, the recycling of FDG is still limited to the certain purposes. In order to expand the possible application of FDG, this study aims to utilize FDG as an activator for ground granulated blast furnace slag. FDG produced by dry- and wet-process were used for the experiments. Slag paste specimens were produced by mixing with deionized water and simulated pore solution, and the role of FDG as an activator for blast furnace slag was evaluated using hydration study by XRD analysis and compressive strength development. According to the results, dry-type FDG was found to work as an activator for blast furnace slag without the presence of soluble alkalis. However, wet-type FDG needs assistance by soluble alkalis in order to work as an activator for blast furnace slag. It was also found that the substitution of dry- and wet-type FDG into blast furnace slag can increase the 28 day compressive strength of slag paste. It is expected that efficient and economical recycling of FDG will be possible if quantitative analysis of strength enhancement according to substitution rate of both dry- and wet-type FDG.

• Journal of the Korea Concrete Institute
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• v.21 no.1
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• pp.3-11
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• 2009

The increased demand and consumption of coal has intensified problems associated with disposal of solid waste generated in utilization of coal. Major utilization of coal by-products has been in construction-related applications. Since fly ash accounts for the part of the production of utility waste, the majority of scientific investigations have focused on its utilization in a multitude of use, while little attention has been directed to the use of bottom ash. As a consequence of this neglect, a large amount of bottom ash has been stockpiled. However, the need to obtain safe and economical solution for its proper utilization has been more urgent. The study presented herein is designed to ascertain the performance characteristics of bottom ash, as autoclaved lightweight foamed concrete product. The laboratory test results indicated that tobermorite was generated when bottom ash was used as materials for hydro-thermal reaction. According to the analysis of variance, at the fresh state, water ratio affects on flow and slurry density of autoclaved lightweight foamed concrete, but foam ratio influences on slurry density, while, at the hardened state, foam ratio affects on the density of dry and the compressive strength but doesn't affect on flexural and tensile strength. In the results of response surface analysis, to obtain target performance, the most suitable mix condition for lightweight foamed concrete using bottom ash was water ratio of 70$\sim$80% and foaming ratio of 90$\sim$100%.