• Journal of the Korean Institute of Gas
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• v.13 no.6
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• pp.9-14
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• 2009

In this study, the stress and deformation characteristics of corner protection in which is fabricated in an insulation area have been analyzed using a finite element method. The proposed corner protection may increase the strength and leakage safeties of conventional LNG storage system. The stress and deformation of LNG storage tank system are computed for an insulation panel box, membrane inner tank, and prestressed concrete outer tank. The FEM computed results indicate that the stress and displacement of new membrane LNG tank system with a corner protection between an inner tank and an outer tank are reduced in comparison to those of a conventional membrane LNG tank. This is explained that the strength safety of LNG membrane tank system may be increased due to a strength stiffness of a corner protection.

• Membrane and Water Treatment
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• v.9 no.5
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• pp.343-351
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• 2018

As membrane fouling is based on various factors, it is a complex phenomenon that is hard to estimate. This study investigated membrane fouling in a thermophilic jet loop membrane bioreactor (JLMBR). With this purpose, four different empirical membrane fouling models with different sludge retention times were applied on the flow data obtained in the system. As a result of the model implementation, it was found for all sludge retention times that, standard blocking is effective in the first 1.5 hours of filtration, while cake filtration was dominant in the remaining duration. Additionally, it was observed that as the sludge retention time increases, membrane fouling rate decreases.

• Journal of Environmental Science International
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• v.9 no.2
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• pp.159-164
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• 2000

For the purpose of development of a liquid membrane permeator which separates metal ions from aqueous solutions continuously and effectively, a continuous membrane permeator with the membrane solution trapped between extraction and stripping phases by two micro-porous hydrophilic films was manufactured. Experimental researches on the separation of zinc ion from aqueous solutions were performed in the liquid membrane permeator with 30 vol % D2EHPA solution in kerosine as liquid membrane. As results, the liquid membrane permeator separates zinc ion from aqueous solutions continuously and effectively in the wide range of operating conditions. A simple mass transfer rate model using equilibrium constant of the extraction reaction for the system used were proposed, and the model was compared with experimental results of separation of zinc ion in the permeator. And the effects of operating factors, such as space time, pH of extraction solution, extraction temperature, on the separation rate of zinc ion in the permeator were experimentally examined.

• Journal of Industrial Technology
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• v.26 no.B
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• pp.157-162
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• 2006

Recently, the humidity adjustment of indoor air is of great importance in air conditioning system as a applied, in buildings, vehicles, and containers for storage and transport of perishable products. Membrane dehumidification or air is potentially attractive because it offers low capital and operating costs, along with low energy consumption. And membrane dehumidification process attracted the attention of the public instead of the other dehumidification processes, such as adsorption, absorption, and refrigeration cycles and so on. In this study, the prepared hydrophilic inorganic membrane-based dehumidifiers(membrane air dehumidification) examined the performance of dehumidification. The surface-modified inorganic membrane prepared in this study showed high dehumidification efficiency(over 80%). The membrane might be very useful for dehumidification industries.

• Journal of the Korean Society of Safety
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• v.10 no.4
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• pp.68-74
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• 1995

This paper analyzes the behaviors of the membrane under drop impact loadings using the acoustic emission technique. The analysis is useful for evaluating the strength of the membrane as well as for studying its damping characterisics due to the corrugation and the ring knot. The membrane for LNG storage tank is basically composed linear and circular elements. Two membrane specimens have approximately same drop impact mass and same drop speed. Locan 320 system with piezoelectric sensor is used in the experimental measurement. Experimental results for the membranes indicated that AE siganls having higher energies were generated with increasing drop impact loadings. It was confirmed that the ring knot. membrane has high absorption of drop impact loadings in comparison with the flat membrane. These results are very important to reliable design and to improve the safey of the membrane components.

• Proceedings of the Membrane Society of Korea Conference
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• 1997.04a
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• pp.87-109
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• 1997

Reverse osmosis(R/O), ultrafiltration(UF) and microfiltration (MF) processes are widely used for water treatment. In the seminar, characteristics of typical membrane modules including tubular, hollow fiber, plate and frame and spiral wound types will be discussed in detail. The design methods based on hydrodynamics for hollow fiber and spiral wound modules will be introduced analytically. Concentration polarization (CP) and membrane fouling mechnism as well as the techniques for CP reduction will be handled. The CP control techniques contain chemically modified membrane surface, pretreatment of feed water, operation of low trans-membrane pressure, chemical or physical cleaning methods and artificial production of various fluid turbulences near the membrane surface, etc. In especially, the recent commercial membrane modules for CP control including module rotation, vibration and Taylor or Dean vortex system will be introduced and discussed in detail.

• Korean Membrane Journal
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• v.1 no.1
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• pp.100-105
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• 1999

A novel system to thicken the concentrated colloidal solution from membrane water treat-ment processes was developed. A hollow-fiber microfilter(hydrophilic polyethylene nominal pore size 0.1 ${\mu}$m total surface area 0.42 m2) was installed in an acrylic housing that has an aeration port 5 cm below the membrane and a clarifier in the bottom. The concentrate was uniformly supplied from the top of the housing. Bacuum filtration caused downward flow of concentrate and as a result thickening interface. The addition of poly-aluminum chloride (PAC) resulted in rapid increase of trans-membrane pressure (TMP) and in no improvement of the filtered water turbidity and thickening process. Two types of con-centrate and concentrate turbidity had little effect on the increase of TMP and concentrate thickening. It was observed that for the same height of membrane housing membrane surface area to housing volume (A/V) ratio had significant effect on the increase of TMP. When the housing volume was increased ten times the increasing rate of TMP was three times faster as compared to the original housing. A hydraulic model successfully simulated the formation and sedimentation of thickening interface.

• Journal of the Society of Naval Architects of Korea
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• v.47 no.2
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• pp.233-241
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• 2010

Scaffolding system in the membrane LNG carrier is a steel structure composed of various pipe-shaped members connected by specific coupling devices. In this study, the automatic design program for scaffolding system in membrane LNG carrier has been developed. It enables user to arrange members easily considering design constraints and input variables such as size of tank, position of legs, level height and so on. In addition to that, it creates finite element analysis model with loading and boundary conditions automatically and carries out structural analysis. With post processor based a state-of-the-art computer graphics, users can easily check the results of structural analysis and make a report for structural safety of scaffolding system.

• Journal of Korean Society of Water and Wastewater
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• v.23 no.4
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• pp.459-469
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• 2009

It is well known that coagulation pretreatment can reduce foulants prior to membrane filtration. The purpose of this research was to investigate the effects of coagulation on fouling of ceramic microfiltration membrane($0.1 {\mu}m$) using pilot plant of $150m^3/day/train$ capacity. Train A membrane system has pretreatment process of ozonation and coagulation while train B has only coagulation. Two types of coagulation operation were investigated: back mixer(rapid mixing with or without slow mixing) which is a conventional mechanically stirred mixer and an inline static mixer. Ozone dose rate for train A was 1 mg/L and ozone contact time was 12 min. The coagulation dose(PACl 10% as $Al_2O_3$) rate was changed 20~40 mg/L according to experimental schedule. In this experimental conditions, the coagulation of back mixer type with rapid mixing(GT=72,000) and slow mixing(GT=45,000) was the best effective in reduction of ceramic membrane fouling regardless preozonation. Especially, the effect of inline static mixer was sensitive to change in water quality. Ozonation mainly affected irreversible fouling rather than reversible fouling in accordance with less adsorption of NOM on the membrane surface. Thus, the increase rate of the nomalized TMP(trans membrane pressure) at $25^{\circ}C$ for train A was relatively lower than that of train B under same coagulation process with same coagulant dosage. The best performance of ceramic membrane appeared in case of combined process with ozonation, therefore this integrated process is able to archive less coagulant dosing and secure a stability of ceramic membrane system.

• Journal of Korean Society of Water and Wastewater
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• v.18 no.6
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• pp.770-777
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• 2004

Three pilot-scale membrane systems were operated using lake water as influent in this study. Microfiltration (MF) membrane with pore size of 0.01 m was used in Systen I of which filtration mode was set at constant pressure of $1kgf/cm^2$. Ultrafiltration (UF) membranes with molecular cutoff (MWCO) of 80,000 and 13,000 were used in System II-1 and II-2, respectively. Constant flow mode was applied at the range between 0.7 and $1.5m^3/m^2{\cdot}d$ (average of $1.1m^3/m^2${\cdot}d) for System II-1 and between 0.37 and $1.65m^3/m^2{\cdot}d$ (average of $1.18m^3/m^2{\cdot}d$) for System II-2. In System I, the flux changed from $1m^3/m^2{\cdot}d$ to $0.2m^3/m^2{\cdot}d$ during the operation time of 5 months. System II showed recovery of 94% under the allowable maximum pressure of $3kgf/cm^2$ during the same operation period. From these results, the efficient operation was observed in constant flow mode with respect to filtration time and recovery. Average filtrate turbidity showed 0.0071 NTU in System I and 0.0054 NTU in System II, which implied that high turbidity removal was obtained in both MF and UF systems with no significant difference between MF and UF. From the fact that membrane flux depends largely on membrane type and operation mode, a guideline of optimum design and operation should be suggested for application of membrane systems to full scale water treatment.