• Environmental Engineering Research
• /
• v.24 no.2
• /
• pp.347-353
• /
• 2019

Although membrane distillation (MD) has great promise for desalination of saline water sources, it is crucial to improve its thermal efficiency to reduce the operating cost. Accordingly, this study intended to examine the thermal energy efficiency of MD modules in a pilot scale system. Two different modules of hollow fiber membranes were compared in direct contact MD mode. One of them was made of polypropylene with the effective membrane area of $2.6m^2$ and the other was made of polyvinylidene fluoride with the effective membrane area of $7.6m^2$. The influence of operation parameters, including the temperatures of feed and distillate, feed flow rate, and distillate flow rate on the flux, recovery, and performance ratio (PR), was investigated. Results showed that the two MD membranes showed different flux and PR values even under similar conditions. Moreover, both flow rate and temperature difference between feed and distillate significantly affect the PR values. These results suggest that the operating conditions for MD should be determined by considering the module properties.

• Applied Chemistry for Engineering
• /
• v.7 no.5
• /
• pp.977-984
• /
• 1996

Liquid-liquid extractions by use of hollow fiber membrane module are fast because of the large surface area per volume. In these membranes, the extractant and feed can be contacted at high speed and two flows are completely independent, so there are no problems with loading and channeling. In this paper, it was investigated the selectivities of extractants for extraction of heavy metals from aqueous solution into organic extractants by using the hollow fiber membrane. To identify the effect of distribution ratio on mass transfer in the membrane, we also compared the distribution ratio with mass transfer coefficient. From these experiments for the system with high distribution ratio, effect of the distribution ratio on mass transfer was weak compare with the low distribution ratio system in the hollow fiber membrane.

• Membrane Journal
• /
• v.4 no.4
• /
• pp.197-204
• /
• 1994

In this study, permeation characteristics of pure $CH_4,\;CO_2$ and $CH_4/CO_2$ gas mixture were examined by permeation experiments through hollow fiber membrane module and experimental results were compared with simulation results. Permeation rate of pure gas increased with increaseing temperature in Arrhenius type. Activation energy was 6.61 kJ/mol for $CO_2$ and 25.26 kJ/mol for $CH_4$. In the permeation experiment of gas mixture, permeate flow rate and $CO_2$ concentration in permeate decreased and $CH_4$ concentration in reject increased with the increase of cut. Separation factor was in the range of 20~40 at 5~20 atm and 20% cut and it increased with pressure and against temperature Experimental values corresponded to numerical values with the deviation of 8% in permeate flow rate and $CO_2$ concentration in permeate and 15% in $CO_2$ concentration in reject.

• Journal of Biomedical Engineering Research
• /
• v.14 no.3
• /
• pp.221-226
• /
• 1993

Modules of hemodiafilter were manufactured by using MC-Hp200 and RC-HP4DOA hoi low fiber membranes of Enka Co. in a unique design. The performances of she hemodiafillers were evaluated by measuring the molecular weight cut-off, ultrafiltration rate, clearance, and pressure drop across the hemodiafiter. As a whole, the performances of the RC-HP400A module were superior to those of the MC-Hp200 module. The modules prepared in thls study showed the satisfactory performances for hemodiafiltration.

• Proceedings of the Membrane Society of Korea Conference
• /
• 2001.05a
• /
• pp.139-141
• /
• 2001

• Proceedings of the Membrane Society of Korea Conference
• /
• 2002.11a
• /
• pp.166-169
• /
• 2002

• Membrane Journal
• /
• v.14 no.2
• /
• pp.142-148
• /
• 2004

This paper presents the enhancement of oxygen transfer efficiency using vibrating intravascular lung assist device (VIVLAD) for patients having chronic respiratory problems. The flow rate was controlled by the pump and monitored by a built-in flow meter. The vibration apparatus was composed of a piezo-actuator, a function generator, and a power amplifier. Gas flow rates of up to 6 L/min through the 120-cm-long hollow fibers have been achieved by exciting a piezo-actuator. The output PVDF sensor and FRF (frequency response function) were investigated by various frequency in VIVLAD. As a result, the maximum oxygen transfer rate was found to occur with maximum amplitude and the transfer of vibration to the hollow fiber membranes. It was excited by the frequency band of 35 Hz at various distilled water flow rates, and various module types.

• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.41 no.8
• /
• pp.537-544
• /
• 2017

The purpose of this study is to analyze the flow characteristics when a staggered hollow fiber membrane module is modeled as a porous medium. The pressure-velocity equation was used for modeling the porous medium, using pressure drop data. In terms of flow characteristics, we compared the case of the "porous medium" when the membrane module was modeled as a porous medium with the case of the "membrane module" when considering the original shape of the membrane module. The difference in pressure drop between the "porous medium" and "membrane module" was less than 0.6%. However, the maximum flow velocity and mean turbulent kinetic energy of the "porous medium" were 2.5 and 95 times larger than those of the "membrane module," respectively. Our results indicate that modeling the hollow fiber module as a porous medium is useful for predicting pressure drop, but not sufficient for predicting the maximum flow velocity and mean turbulent kinetic energy.

• Membrane Journal
• /
• v.20 no.2
• /
• pp.127-134
• /
• 2010

This study is conducted about the system that reduces organism after fermenting food waste from a food waste disposal equipment, divides gas made when food waste is fermented into gas and water, and then sends gas to a reactor again, condenses water, and apply it to the MBR system with submerged MF hollow fiber membranes. A submerged MF hollow fiber membrane module was installed to a food waste disposal equipment and a water treatment system made by Bio Hitech Co,. Ltd. to process food waste generated from a staff cafeteria in a H institute for 90 days. For initial seeding of a food waste disposal equipment, 305 kg of rice bran, chaff, and sawdust as well as 1,648 kg of food were input during the operation, and 1,600 L of condensed wastewater occurred. Fermented by-product after finishing running a food waste disposal equipment was 386 kg and its reduction was shown to be 80%. The organism was processed by applying submerged MF hollow fiber membrane module to the MBR system of condensed wastewater, and the result shows reduction rates were BOD 99.9%, COD 97.5%, SS 98.6%, T-N 54.6% and T-P 34.7% and the total colon bacillus was perfectly eliminated.

• Membrane Journal
• /
• v.28 no.6
• /
• pp.406-413
• /
• 2018

In OBIGGS, a small amount of ozone in the atmosphere damages the polymer membrane. Therefore, the ozone removal device is installed at the front end to prevent the damage of the membrane by reducing the concentration of ozone in the gas delivered to the membrane. In this study, two hollow fiber membranes, PI and PSf, used to fabrication hollow fiber module with an effective membrane area of $6.37cm^2$ for gas separation in OBIGGS. The ozone concentration in the chamber was maintained at 2-3 ppm. The gas was continuously supplied into the module by using a pump. The gas permeation characteristics and the tensile strength were evaluated as a function of ozone exposure time. The PI-based hollow fiber membrane showed only 20% reduction in the transmittance, and remained its original uniformity without any significant changes. However, when PSf type hollow fiber membranes were used, the permeability decreased by more than 80% and the tensile strength decreased by more than 70%.