• Proceedings of the KAIS Fall Conference
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• 2009.12a
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• pp.682-684
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• 2009

본 논문에서는 해수 중에 존재하는 염분을 제거하기 위하여 가스하이드레이트 형성 원리를 이용하였다. 하이드레이트 형성을 위한 guest molecule는 이산화탄소를 사용하였으며, host moelcule로는 3.5% NaCl 물을 사용하였다. 염수에 강한 반응기를 만들기 위하여 스테인레스 강에 epoxy 수지를 코팅하여 실험을 수행하였다. 실험한 결과 70% 이상의 염제거율을 얻을 수 있었으며, 2단 공정이나 3단 공정을 적용할 경우 더욱 높은 염제거율을 얻을 수 있을 것이라고 판단된다.

• Membrane Journal
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• v.15 no.2
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• pp.175-186
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• 2005

An electrodialysis process was operated for a long period to investigate the scale formation on the membrane surface. During the desalination process, concentration of $Ca^{2+}$ and $SO_4^{2-}$ ions increased continuously in the concentrate compartment and eventually caused precipitation on the cation exchange membrane (Neosepta CMX) surface. During the initial scale formation, the performance of the process and membrane characteristics did not show significant changes, except the decrease in limiting current density of the CMX membrane occurring due to increase in the salt concentration in the concentrate compartment. Eventually, the limiting current density of the fouled CMX membrane dropped significantly to $300\;A/m^2$ as water dissociation occurred in the CMX membrane. It was concluded that the fouling was caused mainly by the scale formation on the cation exchange membrane surface in the concentrate and consequent water dissociation. Also the scale formation was reasonably predicted by the solubility of $CaSO_4$.

• Proceedings of the Membrane Society of Korea Conference
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• 2008.05a
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• pp.210-213
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• 2008

• Environmental Engineering Research
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• v.16 no.3
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• pp.165-173
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• 2011

The equilibrium and kinetic adsorption of arsenic on six different adsorbents were investigated with one synthetic and four natural types (two surface and two ground) of water. The adsorbents tested included magnetic ion exchange resins (MIEX), hydrous ion oxide particles (HIOPs), granular ferric hydroxide (GFH), activated alumina (AA), sulfur modified iron (SMI), and iron oxide-coated microsand (IOC-M), which have different physicochemical properties (shape, charge, surface area, size, and metal content). The results showed that adsorption equilibriums were achieved within a contact period of 20 min. The optimal doses of adsorbents determined for a given equilibrium concentration of $C_{eq}=10\;{\mu}g/L$ were 500 mg/L for AA and GFH, 520-1,300 mg/L for MIEX, 1,200 mg/L for HIOPs, 2,500 mg/L for SMI, and 7,500 mg/L for IOC-M at a contact time of 60 min. At these optimal doses, the rate constants of the adsorbents were 3.9, 2.6, 2.5, 1.9, 1.8, and 1.6 1/hr for HIOPs, AA, GFH, MIEX, SMI, and IOC-M, respectively. The presence of silicate significantly reduced the arsenic removal efficiency of HIOPs, AA, and GFH, presumably due to the decrease in chemical binding affinity of arsenic in the presence of silicate. Additional experiments with natural types of water showed that, with the exception of IOC-M, the adsorbents had lower adsorption capacities in ground water than with surface and deionized water, in which the adsorption capacities decreased by approximately 60-95%.

• Environmental Engineering Research
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• v.25 no.4
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• pp.498-505
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• 2020

This study analyzes the velocity and pressure incurred by protruding shapes installed within the inlet part of a pressurized membrane module during operation to determine the fluid flow distribution. In this paper, to find the flow distribution within a module, it investigates the velocity and pressure values at cross-sectional and outlet planes, and 9 sections classified on outlet plane using computational fluid dynamics. From the Reynolds number (Re), the fluid flow was estimated to be turbulent when the Re exceeded 4,000. In the vertical cross-sectional plane, shape 4 and 6 (round-type protrusion) showed the relatively high velocity of 0.535 m/s and 0.558 m/s, respectively, indicating a uniform flow distribution. From the velocity and pressure at the outlet, shape 4 also displayed a relatively uniform fluid velocity and pressure, indicating that fluid from the inlet rapidly and uniformly reached the outlet, however, from detailed data of velocity, pressure and flowrate obtained from 9 sections at the outlet, shape 6 revealed the low standard deviations for each section. Therefore, shape 6 was deemed to induce the ideal flow, since it maintained a uniform pressure, velocity and flowrate distribution.

• Proceedings of the KAIS Fall Conference
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• 2011.12b
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• pp.391-393
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• 2011

본 연구에서는 원자력 발전 및 화력 발전소에서 Turbine 운전 시 열교환기 및 콘덴서에 증기를 응축시 열효율을 높여주기 위해 콘덴서 Tube 내에 이물질 및 스케일을 Sponge Ball을 이용하여 자동으로 제거하는 장치로서 콘덴서 튜브 클리닝 시스템(CTCS)에 사용되고 있는 Screen 재료인 Duplex Stainless Steel UNS S31803의 파손사례에 대해 연구하였다. 파손원인 분석은 스크린의 강도해석, 재료의 화학분석시험, 조직시험 및 점용접부의 신뢰성 시험(Peel-off test)으로 수행되었고 저항용접부의 용접 불량 때문에 발생하였을 확인하였다.

• Proceedings of the KSME Conference
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• 2001.06d
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• pp.17-24
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• 2001

To solve the problems of energy and environment conservation issued recently, mainly in mechanical engineering point of view, R&D's on the thermal, fluid and environmental engineering technology have been carried out by two R&D departments in the Korea Institute of Machinery & Materials (KIMM). Now there are 65 researchers in the two. The representative projects in the field of thermal and fluid engineering are development of an inactive gas generator and development of a cryogenic cooler for electronic sensors. Pyrolysis and melting of wastes, gas treatment using nonthermal plasma, and desalination are important technology to be developed in environmental R&D areas. To reduce the emission from the existing diesel engines for buses, an LPG direct injection type of bus engine is being developed supported by LPG supply companies. These several R&D projects which have been carried out in KIMM are introduced briefly.

• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.1368-1369
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• 2011

이 연구는 최근 물 부족시대를 대비한 차세대 기술로 각광 받고 있는 해수담수화설비의 동력을 기존의 화석연료에서 신재생에너지로 전환하고 있는 세계적인 추세와 기술동향을 살펴보고 국내 적용 가능성을 검토한 것이다. 특히 태양열, 태양광, 풍력 등을 활용하여 MENA(Middle East Asia & North Africa), 스페인, 지중해 연안 등의 지역에서 추진 중인 프로젝트의 성과를 살펴보고, 이를 토대로 극심한 물 부족으로 불편을 겪고 있는 국내 해안 도서지역에 적용할 수 있는 방안을 검토하였다.

• Proceedings of the Membrane Society of Korea Conference
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• 1996.09a
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• pp.121-145
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• 1996

Due to more stringent regulations in drinking water, membrane separation has been playing an increasingly important role. Seawater desalination by reverse osmosis is a typical example and has been used world-wide. Although the existing technology based on coagulation and media filtration is well established and reliable technology, with the advance of industrial and agricultural activities it is difficult for this technology to remove contaminants such as nitrate and synthetic organic chemicals. To meet the drinking water standards and produce higher quality water, several membrane filtration research programs have been initiated which include Japanese MAC21 and New MAC21 projects. In this paper, potable water application of reverse osmosis (RO) and nanofiltration(NF) and their case histories will be explained in more detail.

• Membrane and Water Treatment
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• v.13 no.6
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• pp.259-290
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• 2022

Carbon nanotubes (CNTs), due to their excellent physical, chemical and mechanical properties and their ability to prepare new membranes with attractive properties, have found applications in water and wastewater technology. CNT functionalization, which involves the introduction of different types of functional groups into pure CNTs, improves the capabilities of CNT membranes for water and wastewater treatment. It turns out that CNT-based membranes have many advantages, including enhanced water permeability, high selectivity and anti-fouling properties. However, their full-scale application is still limited by their high cost. With their tremendous separation efficiency, low biofouling potential and ultra-high water flux, CNT membranes have the potential to be a leading technology in water treatment in the future, especially in desalination.