• Korean Chemical Engineering Research
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• v.48 no.2
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• pp.268-274
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• 2010

Emission of heavy metals as hazardous air pollutants has been focused with tightening regulatory limits due to their hazardousness. Measurements and characteristic investigations of heavy metals emitted from a commercial power plant burning anthracite coal have been carried out. The plant consists of a circulating fluidized bed combustor, a cyclone, a boiler and an electrostatic precipitator(ESP) in series. Dust and gaseous samples were collected to measure main heavy metals including gaseous mercury before ESP and at stack. Dust emissions as total particulate matter (TPM), PM-10 and PM-2.5 at inlet of ESP were very high with 23,274, 9,555 and $7,790mg/Sm^3$, respectively, as expected, which is much higher than those from pulverized coal power plants. However TPM at stack was less than $0.16mg/Sm^3$, due to high dust removal efficiency by ESP. Similarly heavy metals emission showed high collection efficiency across ESP. From particle size distribution and metal enrichment in sizes, several metal concentrations could be correlated with particle size showing more enrichment in smaller particles. Mercury unlike other solid metals behaved differently by emitting as gaseous state due to high volatility. Removal of mercury was quite less than other metals due to it's volatility, which was 68% only. Across ESP, speciation change of mercury from elemental to oxidized was clearly shown so that elemental mercury was half of total mercury at stack unlike other coal power plants which equipped wet a scrubber.

• Journal of Korean Society of Environmental Engineers
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• v.31 no.3
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• pp.186-192
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• 2009

In this study, The effects of three different activated carbon materials (each coal, coconut and wood based activated carbons), empty bed contact time (EBCT) and water temperature on the removal of pharmaceutical 4 species (oxytetracycline, tetracycline, trimethoprime and caffeine) in BAC filters were investigated. Experiments were conducted at three water temperature (5, 15 and $25^{\circ}C$) and four EBCTs (5, 10, 15 and 20 min). The results indicated that coal based BAC retained more attached bacterial biomass on the surface of the activated carbon than the other BAC, increasing EBCT or increasing water temperature increased the pharmaceutical 4 species removal in BAC columns. In the coal-based BAC columns, removal efficiencies of oxytetracycline and tetracycline were 87~100% and removal efficiencies of trimethoprime and caffeine were 72~99% for EBCT 5~20 min at $25^{\circ}C$. The kinetic analysis suggested a firstorder reaction model for pharmaceutical 4 species removal at various water temperatures (5~$25^{\circ}C$). The pseudo-first-order reaction rate constants and half-lives were also calculated for pharmaceutical 4 species removal at 5~$25^{\circ}C$. The reaction rate and half-lives of pharmaceutical 4 species ranging from 0.0360~0.3954 $min^{-1}$ and 1.75 to 19.25 min various water temperatures and EBCTs, could be used to assist water utilities in designing and operating BAC filters.

• Korean Chemical Engineering Research
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• v.59 no.1
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• pp.60-67
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• 2021

This study presented techno-economic analysis of a 500 MWe oxy-coal power plant with CO2 capture. The power plant included a circulating fluidized-bed (CFB), ultra-supercritical steam turbine, flue gas conditioning (FGC), air separation unit (ASU), and CO2 processing unit (CPU). The dry flue gas recirculation (FGR) was used to control the combustion temperature of CFB. One FGR heat exchanger, one heat exchanger for N2 stream exiting ASU, and a heat recovery from CPU compressor were considered to enhance heat efficiency. The decrease in the temperature difference (ΔT) of the FGR heat exchanger that means the increase in heat recovery from flue gas enhanced the electricity and exergy efficiencies. The annual cost including the FGR heat exchanger and FGC cooling water was minimized at ΔT = 10 ℃, where the electricity efficiency, total capital cost, total production cost, and return on investment were 39%, 1371 M$, 90 M$, and 7%/y, respectively.

• Journal of Environmental Science International
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• v.22 no.2
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• pp.205-213
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• 2013

This is made of domestic and foreign coal activated carbon of five species, physicochemical adsorption efficient about sterilize products and micro harmful substances and is a result of the economic evaluation. The most well-developed micropores bed volume 123,409 of AC-1 activate carbon appeared to be the best next AC-2, AC-3, AC-4, AC-5 followed by activated carbon was investigated. PFOA and PFOS in the BV 96,000 when evaluating foreign types of adsorption activated carbon adsorption capacity was greater when more than PFOA, PFOS showed that the adsorption well. The economic evaluation of activated carbon usage in chloroform (CUR) was most excellent as a AC-1 4.3 g/day, the next AC-2, AC-3, AC-4, AC-5 there are two types of foreign economic order appears to have appeared, but the current domestic market when applying the price AC-1, AC-3, AC-2, AC-4, AC-5 order was investigated.

• Economic and Environmental Geology
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• v.46 no.4
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• pp.351-358
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• 2013

Methane burns more clearly than any other fossil fuels. Coalbed methane(CBM) is natural gas contained in coal beds. This gas is usually producted from coal that is either too deep or too poor-quality to be mined commercially. While global coalbed methane resource estimates are rough, they indicate between 84 and 377tcm, which compares with proven natural gas reserves of 180tcm. Coalbed methane resources are currently only produced on a major scale in the United States, Canada, Australia and China. In this study, we analysed total 109 published papers for the CBM during the 1990~2012 periods by the programs of 'web of science'. The results of analysis, the CBM study led by the United States, the follow India and Australia. In subject area(web of sciences), Energy Fuels is 57, Engineering 58 and Geology 41 papers, respectively.

• 한국신재생에너지학회:학술대회논문집
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• 2010.06a
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• pp.106.1-106.1
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• 2010

석탄가스화기술은 매장량이 풍부하여 안정적인 공급이 보장되는 석탄을 이용함과 동시에 환경오염물질 감소라는 사회적 요구조건을 충족시키면서 화학제품, 석탄-가스화, 석탄-디젤화, 연료전지, 복합발전 등 다양한 분야에 응용이 가능한 장점이 있다. 특히 석탄가스화복합기술(Intergrated Coal Gasification Combined Cycle, IGCC)은 석탄을 고온, 고압하에서 가스화시켜 일산화탄소(CO), 수소($H_2$)가 주성분인 합성가스를 제조, 정제 후 가스터빈 및 증기터빈을 복합으로 구동하여 전기를 생산하는 친환경 차세대 발전기술로 주목을 받고 있다. 현재 IGCC 기술은 세계적으로 볼 때 상용화단계에 있고, 우리나라의 경우 한국형 IGCC 기술의 확보를 위한 연구사업이 진행중에 있다. 본 연구는 IGCC 발전플랜트의 발전효율을 결정하는 가장 중요한 부분이라 할 수 있는 가스화반응기의 모델링 기술을 개발하는 목적으로 진행되었다. 본 연구에서는 석탄가스화 반응기에서 발생하는 석탄의 휘발화와 Char의 표면반응 그리고 기상에서의 가스화반응등의 현상을 전산유체역학(Computational Fluid Dynamics)을 이용하여 모델링하는 방법론이 연구되었다. 해석을 위한 형상은 해석에 소요되는 시간을 줄이고, 형상이 해석결과에 미치는 영향을 줄이고자 2차원으로 구성하였다. 해석을 위한 수학적모델으로는 난류모델, 가스화반응모델, Lagrangian particle tracking, Char reaction 등을 포함하였고, 해석을 위한 Solver는 Fluent를 이용하였다. 모델링결과에 의해 예측되는 합성가스의 조성을 상용급 IGCC 가스화기의 운전결과와 비교해 본 결과 본 연구에서 설정한 모델로 예측되는 온도 및 가스농도가 실험치와 유사하게 나타남을 알 수 있었고 이를 통하여 본 연구에서 설정한 모델링방법이 적절함을 알 수 있었다.

• Journal of Soil and Groundwater Environment
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• v.18 no.7
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• pp.73-80
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• 2013

Fine suspended solids from coal mine drainage were treated in the treating plant, using two different pilot-scale inclined clarifiers: radial and lamella types. Suspended solids in the mine drainage were monitored along with other geochemical factors, and metal contents. Fe and Mn are the main chemical components in the drainage, which exist predominantly as total metal forms, whereas dissolved portion is negligible. The raw mine drainage is subject to physical and chemical treatment using $CaCO_3$ and NaOH, therefore the suspended solids are thought to be composed of Fe and Mn precipitates, possibly $Fe(OH)_3$, along with carbonate precipitates. The elemental composition of precipitates are confirmed by SEM-EDS analysis. As nearly all the dissolved ions were precipitated in the primary process by $CaCO_3$, no further aeration or prolonged oxygenation are of necessity in this plant. Adoption of inclined clarifier proved to be effective in treating fine suspended solids in the current plant. Successful application of the inclined clarifier will also be beneficial to improve the current treating process by excluding the current application of chemical agent in the first stage. The final effluents from the pilot plant meet the national standards and the low dissolved Fe and Mn contents are expected not to cause secondary precipitation after discharge.

• Journal of Korean Society of Environmental Engineers
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• v.29 no.2
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• pp.205-213
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• 2007

We have studied NOM(natural organic matters) adsorption and biodegradation on 3 kinds of activated carbon and a anthracite. Coal based activated carbon showed the highest DOC(dissolved organic carbon) adsorption capability and roconut(samchully), wood (pica) in the order among the 3 kinds of activated carbon(F400). The biomass amount and activity also showed on coal, wood and coconut based activated carbon in the order. Over 15 minutes EBCT(empty bed contact time) needed to achieve 10 to 17% average removal efficiency and $18\sim24%$ maximum removal efficiency of NOM biodegradation in biofilter using anthracite. Hydrophobic and below 10,000 dalton NOM was much easier to adsorb into the activated carbon than hydrophilic NOM, THMFP(trihalomethane formation potential) and BDOC (biodegradable dissolved organic carbon)$_{slow}$ were much easier than HAA5FP(haloacetic acid 5 formation potential) and $BDOC_{rapid}$ to adsorb into the activated carbon. Hydrophilic and below 1,000 dalton NOM was much easily biodegraded and HAA5FP and $BDOC_{rapid}$ was easier than THMFT and $BDOC_{slow}$ to biodegrade in the biofilter.

• Korean Chemical Engineering Research
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• v.57 no.4
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• pp.492-500
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• 2019

In this study, the effect of chemical additives on the reduction of fine particles was identified in $9.2MW_e$ commercial scale circulating fluidized bed boiler firing bituminous coal. Futhermore, a simple and effective method of fine particle collection has been developed to collect the fine particles of the boiler during fossil fuel combustion. Chemical additives were used to reduce particles below 10 PM in the flue gas, and borax solution was used as a chemical additive. In order to identify the particle behavior of PM 10 or less among the collected fine particles, it was analyzed through particle size analyzer and SEM analysis. The Borax solution tends to absorb molten mineral in the flue gas and make fine particles grow. As a result, it was analyzed that particles smaller than $10{\mu}m$ were reduced by using borax solution.

• Proceedings of the Korean Environmental Health Society Conference
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• 2003.06a
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• pp.152-156
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• 2003

Air pollution problems due to the emission of pollutants from the various industrial facilities become serious issues and lots of air pollution control processes have been developed. To remove the SO$_2$ and NOx emitted from the solid waste incinerator and coal fired power plants, we studied the Ca-based sorbent which was prepared by waste clam and limestone. The objectives of this study were to develop a clam-based sorbent for removal of SO$_2$ and NOx, and to investigate the physicochemical properties of the waste clam sorbent. In order to determine acid gas removal capacity of sorbent, the batch study on SO$_2$ and NOx removal was performed with the Ca-based sorbent in the fixed bed reactor. Results of the research revealed that clam-based sorbent can be used as the iron-manufacturing industry and chemical adsorbents for the removal of acid gases because the lime content of the waste calm was more than 53.92%. From physicochemical analysis and gas reaction experiments, it could be concluded that clam is good sorbent for the removal of SO$_2$ and NOx in waste incinerator and flue gas desulfurization processes.