• Journal of Korean Society of Environmental Engineers
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• v.35 no.8
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• pp.547-553
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• 2013

This paper investigates the effect of coal-fired fly ash on dry $CO_2$ sorbents as the supports and additives. For this purpose, various kinds of dry sorbent were manufactured by mixing fly-ash, the primary $CO_2$ absorption components (NaOH and CaO) and water with their different combination. Thereafter, their $CO_2$ absorption performance and the property were analyzed. As a result, variation of absorption efficiency and temperature as well as $CO_2$ desorption of the sorbents are confirmed, which may be primarily ascribed to fly-ash addition to the sorbents. Particularly, fly-ash effect is strongly measured in the sorbent manufactured by mixing all four components (named WNCF sorbents). Absorption efficiency of WNCF sorbents at $550^{\circ}C$ is 35.6% higher than that of flyash free sorbent and desorption is solely observed in WNCF sorbents. Fly-ash in WNCF sorbents leads to increase the dispersity of $CO_2$ absorption components and decrease their particle size in the sorbents. In addition, fly-ash is used as the supports and pozzolanic reaction is hindered by NaOH in WNCF sorbent. Furthermore, $CO_2$ desorption from the sorbents may be due to fly-ash. The interaction between fly-ash and $CO_2$ absorption components substantially attenuate the strength between captured $CO_2$ in CaO and NaOH.

• Plant Journal
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• v.13 no.2
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• pp.46-51
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• 2017

In this study, the boiler efficiency and the change of boiler combustion state with the burner operation of the uppermost layer of 870MW opposite fired coal boiler were measured. Test results showed that the boiler efficiency was high in the order of the uppermost layer simultaneous operation of the front and rear burners, the front burner, and the rear burner operation. When the front and rear burners were operated simultaneously, the heat absorption rate of water walls in the boiler furnace was uniform at four side, and the temperature deviation of the left and right steam on the convection front surface decreased. As the heat absorption rate of the boiler improved, the loss of boiler exhaust gas decreased and the coal supply amount decreased by 8 tons/hour compared to the operation of the rear burner. This will contribute not only to the reduction of fuel cost but also to the reduction of greenhouse gas emissions.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.1
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• pp.21-27
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• 2016

Global warming due to greenhouse gas emissions is considered as a major problem worldwide, and many countries are making great efforts to reduce carbon dioxide emissions. Many technologies in post-combustion, pre-combustion and oxy-fuel combustion $CO_2$ capture have been developed. Among them, a hybrid pre-combustion $CO_2$ capture system of a water gas shift (WGS) reactor and a membrane gas separation unit was investigated. The 2 stage WGS reactor integrated high temperature shift (HTS) with a low temperature shift (LTS) was used to obtain a higher CO conversion rate. A Pd/Cu dense metal membrane was used to separate $H_2$ from $CO_2$ selectively. The performance of the hybrid system in terms of CO conversion and $H_2$ separation was evaluated using a 65% CO, 30 % $H_2$ and 5% $CO_2$ gas mixture for applications to pre-combustion $CO_2$ capture. The experiments were carried out over the range of WGS temperatures ($200-400^{\circ}C$), WGS pressures (0-20bar), Steam/Carbon (S/C) ratios (2.5-5) in a feed gas flow rate of 1 L/min. A very high CO conversion rate of 99.5% was achieved with the HTS-LTS 2 stage water gas shift reactor, and 83% $CO_2$ was concentrated in the retentate using the Pd/Cu membrane.

• Resources Recycling
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• v.29 no.3
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• pp.51-60
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• 2020

This study was carried out to get the optimum conditions for manufacturing high refractive glass beads from waste fluorescent lamp glass. Chemical composition, X-ray diffraction pattern, particle size distribution, refractive index of glass beads, and the effect of air mixing ratio and ejection rate were investigated. The obtained results are as follows. The X-ray diffraction pattern and chemical composition of glass beads made of waste fluorescent glass are similar to common glass except ReO₂ 0.0108 wt%, BaO 0.071 wt%, NiO 0.0039 wt% and CaO 7.8 wt% but 11.7 wt% of common glass. The glass beads made of waste fluorescent lamp glass have the narrower particle size distribution of and the higher refractive index than the glass beads made of common glass. The optimal conditions of kiln operation for manufacturing glass beads from waste fluorescent lamp glass are 20 m/sec of ejection rate, 1.7 of air mixing ratio, and 940℃ of temperature.

• Journal of Korean Society of Environmental Engineers
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• v.32 no.10
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• pp.957-964
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• 2010

The deactivated catalyzed diesel particulate filter-trap (DPF) was remanufactured by ultrasonic wave treatment with various prepared solutions, followed by active component re-impregnation, and the emission control performance and surface properties of remanufactured DPF were studied at various remanufacturing conditions. The proper ultrasonic wave cleaning time at various prepared solutions and optimal re-impregnation amounts of active component for the best emission control performance of DPF were investigated and its performance tests were also carried out with various temperatures for the conversions of CO, THC (total hydrocarbon) and PM (particulate matter) by catalytic reaction test unit using bypass gas from the diesel engine dynamo system. It was found that the emission control performance of DPF remanufactured with the high-temperature air washing, ultrasonic wave cleaning at acid/base solutions and active component re-impregnation method was recovered to 95% level of its activity compared to that of the fresh DPF, which was caused by removing the deactivating materials from the surface of the DPF, through the analyses of performance test and their surface characterization by Optical microscope, EDX, ICP, TGA, and porosimeter.

• Journal of the Korea institute for structural maintenance and inspection
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• v.22 no.2
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• pp.154-160
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• 2018

Cement industries are considered key industries for reducing carbon emissions, and efforts are off the ground to reduce the use of cement in the concrete sector. As a part of this effort, research is off the ground to utilize a large amount of industrial by-products that can be used as a substitute for a part of cement. Concrete using industrial by-products has advantages such as durability, environment friendliness and economical efficiency, but there are problems such as retarding and early-age strength deterioration. Therefore, this study aimed to reduce the use of cement and solve the problem of early-age strength deterioration while using fly ash, which is an industrial by-product. Accordingly, it was confirmed that the strength was improved at all ages irrespective of curing temperature by accelerating the hydration reaction by using high fineness cement. Subsequently, high fineness cement was partially replaced with fly ash and the strength development characteristics were examined. As a result, it was possible to exhibit strength equal to or higher than ordinary portland cement even at the early age. Also, it was confirmed that even when the fly ash is replaced by 30%, it is possible to shorten the time for dismantling the forms of vertical and horizontal members.

• Proceedings of the Korea Water Resources Association Conference
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• 2012.05a
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• pp.593-593
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• 2012

본 연구는 화력 및 원자력 발전소로 취입된 냉각수(circulating and essential service water)가 복수기로부터 온배수 형태의 개수로 흐름으로 표층배수 될 경우 수온을 저감시키기 위해 주입하는 희석수(by-pass cooling water)와의 혼합효과의 효율성을 증대시키고, 불리한 수리현상을 야기하지 않으며, 경제적인 배수로 구조물을 고찰하기 위한 목적으로 시도되었다. 배수로 구조물 내 온배수와 희석수가 혼합되는 구간을 혼합지(mixing basin)라 하는데, 본 과업에서는 ${\bigcirc}{\bigcirc}$발전소의 배수로 구간 중 혼합지를 대상으로 FLOW-3D$^{(R)}$를 이용한 3차원 수치모형을 구축하고, 총 9개에 해당하는 각 대안별 현상을 분석하고 비교하였다. 각 대안들의 차이점은 배수로에 설치되는 보조구조물들의 형상과 배열 등이며, 복수기로부터 나오는 배출수의 수온은 $42^{\circ}C$, 희석수는 $35^{\circ}C$이고, 본 과업의 주요 관심대상 물리량은 유속과 온도이다. 배수로에 아무런 보조 구조물이 없는 형태인 기본 계획안을 검토한 결과, 평균 $3.31^{\circ}C$의 수온강하가 이루어졌으나, 우안 쪽으로 강한 흐름이 발생하여 수온의 좌우편차가 $4.61^{\circ}C$ 가량 발생하는 것으로 나타났다. 기본 계획안의 검토결과를 보완하기 위한 대안으로 연직 흐름의 소산을 위해 고안된 잠형 소파블록(baffle block) 설치안은 평균 $3.06^{\circ}C$의 수온강하가 이루어지고 $4.44^{\circ}C$의 수온 좌우편차가 발생했다. 지그재그(zigzag) 형태의 흐름을 만들어 혼합효과를 올리기 위한 미로형 수제(labyrinth groin) 설치안은 평균 $5.33^{\circ}C$의 수온강하가 이루어지고, $1.43^{\circ}C$의 수온 좌우편차를 보여줘 검토했던 대안들 중 가장 좋은 결과를 보여주었다. V자 배열 소파블럭(deformed block) 설치안은 연직 및 수평방향의 소산을 기대했으나 평균 $3.00^{\circ}C$의 수온 강하와 $4.41^{\circ}C$의 수온 좌우편차를 나타냈다. 벤츄리(Venturi) 형태의 흐름을 발생시키기 위한 병목형(bottleneck) 수로안은 평균 $3.18^{\circ}C$의 수온강하와 $3.94^{\circ}C$의 수온 좌우편차, 흐름의 소산과 흐름방향을 변화시키기 위한 와형 수제(swirl groin) 설치안은 평균 $2.24^{\circ}C$의 수온강하와 $1.48^{\circ}C$의 수온좌우편차, 우안 흐름을 지연시키기 위한 물방석(water cushion) 수로안은 평균 $3.03^{\circ}C$의 수온강하와 $4.50^{\circ}C$의 수온 좌우편차, 우안의 흐름을 좌안으로 보내기 위한 분사형(injector) 수로안은 평균 $3.13^{\circ}C$의 수온강하와 $4.45^{\circ}C$의 수온 좌우편차, 우안의 흐름을 막기 위한 외팔형 수제(cantilever groin) 설치안은 평균 $3.11^{\circ}C$의 수온강하와 $3.02^{\circ}C$의 수온 좌우편차가 발생하는 것으로 나타났다.

• Proceedings of the Korea Water Resources Association Conference
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• 2016.05a
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• pp.520-520
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• 2016

석유 화학공장에서 발생하는 spent sulfidic caustic (SSC) 폐수는 액화석유가스(LPG)나 천연가스(NG)의 정제과정에서 발생되는 것으로 고농도의 sulfide와 cresylic, phenolic 그리고 mercaptan 등이 포함된 독성과 냄새를 유발하는 물질이다. 이러한 물질들은 LPG나 NG의 정제과정에서 높은 산도를 가진 휘발성 황화합 물질들을 제거하기 위해 사용된 NaOH가 $H_2S$와 반응하여 발생하는 것이다. 진한 갈색 또는 검은색을 띄는 SSC 폐수는 12 이상의 높은 pH를 가지고 있으며 5~12 wt%의 높은 염분도를 가지고 있다. 또한 강한 부식성과 독성을 가진 황화합물의 농도가 1~4 wt%이며, 방향족 탄화수소 물질 (i.e. methanethiol, benzene, tolune and phenol)들도 다량 함유되어 있다. 따라서 이러한 유해 물질들은 기존의 하수처리 공정으로 방류하기 전에 완벽하게 처리해야만 하수처리 공정의 오염 부하량을 줄일 수 있다. 습식산화공정은 SSC 폐수를 처리하기 위해 흔히 사용되고 있는 물리-화학적 처리 공정이지만 고비용, 고에너지가 필요하며, 고온 및 고압에서만 작동되어 안전상의 문제점을 갖고 있다. 또한 습식산화공정을 거친 폐수는 배출허용기준을 만족하기 위해 생물학적 2차 처리가 반드시 필요하다. 철-과산화수소를 이용하는 펜톤산화 공정, 그리고 sulfide를 sulfate로 전환시키는 생물학적 처리 공정은 황화합물의 완전한 무기물화가 힘들며, 현장 적용 시 기술적 경제적 부담이 크다. 이러한 단점을 극복하고, SSC 폐수를 효과적으로 처리하기 위해 본 연구는, 높은 흡착력과 광산화력을 가진 흡착광산화 반응 시스템(Adsorption Photocatalysis System, APS)을 개발하였다. APS는 SSC 폐수를 시스템 내부로 유입하여 수중의 오염물질을 흡착광산화제로 구성된 반응구조체가 흡착하고, 흡착된 오염물질을 UV에너지와 이산화티타늄 광촉매의 광화학반응에 의해 최종적으로 무해한 물질로 환원시키는 폐수처리시스템이다. APS의 반응구조체는 태양에너지 및 인공에너지원에 의해 활용 가능하며, 난분해성 유기화합물질을 물과 이산화탄소로 분해할 수 있는 친환경적이고 경제적인 소재로서 널리 쓰이고 있는 이산화티타늄 광촉매와 화력발전소의 높은 소성온도에 의해 연소된 후 발생되는 bottom ash를 이산화티타늄의 지지체로 사용하여 높은 흡착력과 광촉매 산화력을 가진 복합물이다. 개발된 APS에 의해 SSC 폐수를 처리한 결과, COD 86.1%, 탁도 98.4%, sulfide 99.9%의 높은 처리효율을 보여주고 있다. 따라서 본 연구를 통해 개발된 APS는 강한 부식성과 독성 그리고 높은 농도를 가지고 있는 SSC 폐수를 효과적으로 처리할 수 있다.

• Korean Journal of Soil Science and Fertilizer
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• v.31 no.1
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• pp.77-84
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• 1998

In order to investigate microbiological control of malodors, particularly including ammonia, the effect of three thermophilic ammonium tolerant bacteria strains. TAT112. TAT117 and TAT119, were tested during composting of pig manure in the laboratory scale composters. The total weight, volatile solids and BOD of the pig manure compost were decreased during composting process in all treatments. The temperature in all treatments rose in first 3 days dramatically, but that in control without inoculation reached its maximum most lately among the treatments. The nitrogen content of drain water accumulated inside and outside composter, and trapped in 6N $H_2SO_4$ was lower in TAT112 inoculated composter than in control. However, it was not lower in the treatment of TAT117 and TAT119 inoculated. Ammonia concentration in the exhaust gas monitored everyday during composting also demonstrated that it was lowest at TAT112 inoculated among all treatments. It was appeared to have an effect on reducing ammonia emission at the treatment of TAT112 inoculated than the control.

• Journal of the Korean Society of Marine Environment & Safety
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• v.27 no.6
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• pp.898-904
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• 2021

This experimental study aims to investigate the use of a wet electrostatic precipitator as a post-treatment device to satisfy the strict emission regulations for sulfur oxides and particulate matter (PM). The inlet/outlet of a wet electrostatic precipitator was installed in a funnel using a marine four-stroke diesel engine (STX-MAN B&W) consuming marine heavy fuel oil (HFO) with a sulfur content of about 2.1%. Measurements were then obtained at the outlet of the wet electrostatic precipitator; an optical measuring instrument (OPA-102), and the weight concentration measurement method (Method 5 Isokinetic Train) were used for the PM measurements and the Fourier transform infrared (FT-IR; DX-4000) approach was used for the sulfur oxide measurements. The experimenst were conducted by varying the engine load from 50%, to 75% and 100%; it was noted that the PM reduction efficiency was a high at about 94 to 98% under all load conditions. Additionally, during the process of lowering the exhaust gas temperature in the quenching zone of the wet electrostatic precipitator, the sulfur dioxide (SO₂) values reduced because of the cleaning water, and the reduction rate was confirmed to be 55% to 81% depending on the engine load.