• Journal of Korean Society for Atmospheric Environment
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• v.28 no.2
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• pp.172-181
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• 2012

Mercury is one of the most hazardous air pollutants. Recently, mercury has been a concern in domestic and overseas because it has lethal toxicity, long distance transport, persistence and bioaccumulation in the environment. Stationary combustion sources such as coal-fired power plants, waste incinerators, and cement kilns are the major sources of mercury emissions. The objectives of this study were to measure the concentration for mercury from coal-fired power plants and to calculate emission factor to estimate its emission. The results showed that the mercury concentrations in the flue gas were 1.63-3.03 mg/$Sm^3$ in anthracite-fired power plants (average 2.32 mg/$Sm^3$) and 1.95-3.33 mg/$Sm^3$ in bituminous-fired power plants (average 2.6 mg/$Sm^3$). Mercury emission factor was estimated as 25.74 mg/ton for anthracite-fired power plants and 12.48 mg/ton for bituminous-fired power plants. Because actual measurements are limited in quantity, it is desirable to refine our estimates by extending the actual measurements.

• Clean Technology
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• v.8 no.1
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• pp.1-9
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• 2002

Mild pyrolysis of four different coals (two bituminous coals and two Korean antracite) was investigated. Desulfurization characteristics, weight loss and variation of heating values were studied. As operating variables of experiment, pyrolysis temperature($350{\sim}550^{\circ}C$), pyrolysis time(5~20 min.) and particle size(0~3.55mm) were examined. The maximum sulfur removal rate of bituminous coal and anthracite were 38% and 28%, respectively. The optimum mild pyrolysis conditions were 10~15 min for pyrolysis time and $450{\sim}550^{\circ}C$ for pyrolysis temperature. The mild pyrolysis was effective to reduce organic sulfur content. Heating values of char per mass after pyrolysis increased about 5% compared to raw coal. The effect of coal particle size on the desulfurization was not observed.

• Journal of Environmental Health Sciences
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• v.29 no.3
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• pp.79-85
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• 2003

The purpose of this study was to disclose the manufacturing process of activated carbon using coal. It investigated the influences on the physical properties that were manufactured activated carbon by using anthracite coal, bituminous coal under carbonizated and activated condition. The adsorption capacities of organic material were superior when the ash content was lower 5∼10%, and the iodine value was about 1,000 mg/g, the adsorption capacity decreased rapidly when ash content was over 15%. The manufactured activated carbon were found characteristics such as the iodine value was over 1,031 mg/g, the specific surface area was over 1,032 $m^2$/g and the hardness was over 95% under manufacturing conditions which were carbonizated temperature of $600^{\circ}C$( 180 minute), activated temperature of 95$0^{\circ}C$(210 minute) and steam weight of 6 $m\ell$/min.100 g coal.

• Proceedings of the Korea Society for Energy Engineering kosee Conference
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• 1995.05a
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• pp.158-162
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• 1995

Synergistic effects of mixed solvents, especially with mixtures of CS$_2$ with electron donor solvents, in inducing desired structural changes in coals were studied by solvent swelling techniques in addition to differential scanning calorimetric analyses. Mixed solvents exhibit significant synergistic efficacy in swelling the coal structure of medium bituminous rank. This synergy effect appears to be physical origin that is closely related to matching solubility parameters. Since the swollen coal structure can be obtained by mixed solvents with CS$_2$ at room temperature instead of high temperature, many possible technological pathways for economical utilization of coal might be sought.

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2008.10a
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• pp.228-229
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• 2008

• Journal of Korean Society for Atmospheric Environment
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• v.27 no.5
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• pp.485-493
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• 2011

In Korea, PM (Particulate Matter) emissions caused by coal-fired power plants are measured by a system, so called Clean Air Policy Support System (CAPSS), which uses foreign emission factors. However, the system fails to reflect the characteristics of domestic power plants. In this regard, this study aims to develop local, accurate domestic emission factors. The study measured the amount of TSP (Total Suspended Particulates), PM10 and PM2.5 by collecting samples from the latter parts of pollution control devices which were installed at 3 bituminous-fired power plants and 3 anthracite-fired power plants. The results showed that the average concentrations of TSP, PM10 and PM2.5 measured at bituminous-fired power plants were 4.63 mg/$Sm^3$, 2.96 mg/$Sm^3$ and 3.07 mg/$Sm^3$ respectively, much higher than those from anthracite-fired power plants (2.96 mg/$Sm^3$, 2.47 mg/$Sm^3$ and 1.37 mg/$Sm^3$, respectively). In addition, bituminous-fired power plants showed higher ratios of PM10/TSP and PM2.5/TSP with 0.66 and 0.92, respectively, compared to 0.82 and 0.46, the ratios of PM10/TSP and PM2.5/TSP measured in anthracite-fired power plants. Emission factors based-on concentration measurements were also higher for bituminous-fired power plants, and PM with smaller particles tended to have bigger difference in emission factors between the two fuels. This study calculated the amount of PM emissions by using the estimated emission factors. When it comes to the PM emissions, it was less than that of CAPSS while similar to that of CleanSYS in its amount. It is expected that the emission factors developed by this study will be used in Korea replacing foreign emission factors currently used in Korea by ensuring the objectivity and reliability as domestic emission factors.

• Korean Chemical Engineering Research
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• v.46 no.3
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• pp.443-450
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• 2008

Efficient use of low rank coals (LRC) have been investigated as a method to cope with recent high oil price. Among the coals used in industry, lignite and sub-bituminous coals are belong to the LRC, and have abundant deposit and are distributed worldwide, but high moisture contents and self ignition properties inhibits their utilization. In this paper, chemical coal cleaning to produce ash-free coal from LRC has been investigated. Two technologies, that is, UCC(Ultra Clean Coal) process removing ash from coal and Hyper Coal process extracting combustibles from coal were compared with. UCC process has merits of simple and reliable when it compared with Hyper Coal process, but the remaining ash contents werehigher than Hyper Coal. Hyper Coal has ash contents under the 200ppm when raw coal is treated with appropriate solvent and ion exchange materials to remove alkali materials in extracted solution. The ash-free coal which is similar grade with oil can be used as alternate oil in the industry, and also used as a high grade fuel for IGCC, IGFC and other advanced combustion technology.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.35 no.10
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• pp.997-1003
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• 2011

In order to investigate devolatilization characteristics for ashless coal with relatively low ash content and high heating value, an experiment was performed in different bed configurations of TGA and DTF(Drop Tube Furnace) at atmospheric pressure condition. The heating rate was $10^{\circ}C$/min up to $950^{\circ}C$ in TGA, while the temperatures of DTF varied from 500 to $1300^{\circ}C$ in step of $200^{\circ}C$. A weight loss and particle temperature were obtained to determine devolatilization kinetics. The kinetic parameters including an activation energy and pre-exponential factor for ashless coal were obtained using Coats-Redfern method in TGA and single step method in DTF. Furthermore, the devolatilization kinetics of the ashless coal were compared with the results of different kinds of conventional coal such as sub-bituminous and bituminous. The results show that the activation energy of devolatilazation for ashless coal is lower than those of others in fixed and entrained conditions.

• Journal of the Korean Society of Combustion
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• v.18 no.3
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• pp.44-53
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• 2013

In this study, the economic evaluation for imported coals was conducted for power plant based on thermo-dynamical performance analysis. The number of coal types considered was 1,755 imported by five power generation companies in Korea during the 2010-2012. The higher heating value (HHV) of the coals ranged 4,000-6,500 kcal/kg, mostly sub-bituminous. The 1D thermo-dynamical performance modeling was performed for a 500 MWe standard power plant using PROATES code. It was founded that the low rank coals had negative effects on the plant efficiency mainly due to the increased heat loss by moisture, hydrogen and flue gas. Based on the performance analysis, the economic performance of the coals was evaluated. The apparent price of low-rank coals tended to be significantly lower than design coal; for example, the unit price of coal with a HHV of 4,000 kcal/kg was 57% of the reference coal having 6,080 kcal/kg. Considering the negative effects leading to a decrease in the thermal performance, heating value compensation, and increased parasite load, the corrected unit cost for the coal with 4,000 kcal/kg was 90.7% of the reference coal. Overall, the cost saving by imported coals was not high as expected.

• Journal of environmental and Sanitary engineering
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• v.14 no.3
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• pp.63-70
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• 1999

A study on the zeolite synthesized of bituminous coal fly ash from power plant has been carried out to reuse industrial waste. The synthesized zeolite was proved to be 4A type by means of the X-ray diffraction analysis and the degree of crystallinity was found to be higher than 90%. Then the synthesized zeolite was used as an adsorbent to remove the heavy metal ions in the CU, Pb, and Cd containing wastewater and water. Also, adsorption characteristics and kinetics of synthesized zeolite in the each metal ion solutions were studied. In each ion solutions, the adsorbed amounts of Pb, Cd, and Cu to the unit weight of synthesized zeolite were 141.6, 118.8, and 131.4mg/g respectively when each metal ion concentration was 500mg/L solution. The adsorption kinetics was fitted well to the Freundlich isotherms. The value of l/n for Pb, Cd, and Cu and 0.27, 0.50, and 0.66, respectively. Those results showed that the synthesized zeolite could be used as an adsorbent to remove single heavy metal ions in the wastewater and water. The heats of adsorption, H values of Pb, Cd, and Cu were 4.87, 14.95, and 18.23kacl/mol by the Henry-van't Hoff equation.