• Membrane Journal
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• v.25 no.6
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• pp.465-477
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• 2015

Recently membrane-based gas separation has attracted a lot of attention due to the growing demands on energy efficient separation processes. Current membrane-based gas separation is dominant by polymer membranes and limited mostly to non-condensable gases rather than condensable gases such as hydrocarbon isomers due to the limitation s of polymer materials. Metal-organic framework (MOF) materials, consisting of metal ions and organic ligands, have received a tremendous attention as membrane materials due to high surface area, controllable pore structure, and functionality. In this review, we provide a recent development of MOF membrane preparation methods and their gas separation applications.

• International Journal of Air-Conditioning and Refrigeration
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• v.17 no.3
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• pp.88-93
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• 2009

Lubricant oil is needed in air conditioning and refrigeration system because the compressor requires oil to prevent surface to surface contact between its moving parts, to remove heat, to provide sealing, to keep out contaminants, to prevent corrosion, and to dispose of debris created by wear. Thus, the oil separation in an oil separator is one of the most important characteristics for proper compressor operation. In this study, a gravity type of oil separator is used. Oil separation characteristics have been investigated for $CO_2$/PAG mixture in the range of oil concentration 0 to 5 weight-percent and the mixture temperature range of $0^{\circ}C$ to $15^{\circ}C$ at 50 bar and $70^{\circ}C$ to $90^{\circ}C$ at 80 bar. The results obtained indicate that the oil separation is increased with an increase in the oil concentration. It is also found that the oil separation in liquid state is increased with an increase in the mixture temperature while the oil separation in gas state is decreased.

• Membrane Journal
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• v.28 no.2
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• pp.136-141
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• 2018

Carbon dioxide ($CO_2$) exists not only as a component of natural gas, biogas, and landfill gas, but also as a major combustion product of fossil fuels which leads to a major contributor to greenhouse gases. Hence it is essential to reduce or eliminate carbon dioxide ($CO_2$) in order to obtain high fuel efficiency of internal combustion engine, to prevent corrosion of gas transportation system, and to cope with climate change preemptively. In recent years, there has been a growing interest in not only conventional membrane-based separation but also new adsorbent-based separation technology. Particularly, in the case of metal-organic frameworks (MOFs), it has been received tremendous attentions due to its unique properties (eg : flexibility, gate effect or strong binding site such as open metal sites) which are different from those of typical porous adsorbents. Therefore, in this study, stereotype of two MOFs have been selected as its flexible MOFs (MIL-53) representative and numerous open metal sites MOFs (MOF-74) representative, and compared each other for $CO_2/CH_4$ separation performance. Furthermore, varying and changeable separation performance conditions depending on the temperature, pressure or samples' unique properties are discussed.

• Membrane Journal
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• v.21 no.2
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• pp.177-192
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• 2011

Hollow fiber membrane using CTA polymers were prepared by the phase separation method for the separation and purification of biogas and the hollow fiber gas separation membrane modules with the effective surface area of 0.17 $m^2$ were prepared. The pure gas permeation properties of membrane modules for methane, oxygen and carbon dioxide were measured. The permeance of $CO_2$ and $CH_4$were 0.46 GPU and 18.52 GPU, respectively, therefore, the high $CO_2$/$CH_4$ selectivity of 40.4 was obtained. The separation and purification test for 4 different simulated mixed gases were carried out after the pure gas test and the gas concentration and flux of the permeate at the various stage-cut were measured from the 1 stage, 2 stage, and 3 stage cascade of membrane modules. In the 1 stage test, the concentration of $CH_4$ increased as the increase of the stage-cut, while the $CH_4$ recovery efficiency ratio decreased. In the 2 stage test, the $CH_4$ recovery efficiency ratio increased compared to the 1 stage. The 3 stage test was employed to reduce the loss of $CH_4$ in biogas and the result showed less than 5% of $CH_4$ recovery loss.

• Proceedings of the Membrane Society of Korea Conference
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• 2004.05b
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• pp.147-152
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• 2004

Gas separation membrane technology is useful for a variety of applications [1, 2]. such as hydrogen recovery from reactor purge gas, nitrogen and oxygen enrichment, water vapor removal from air, stripping of carbon dioxide from natural gas. etc. Although membrane separations are attractive because of low energy costs and simple operation, low permeabilities and/or selectivity often limit membrane applications [3, 4].(omitted)

• Proceedings of the Membrane Society of Korea Conference
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• 1994.10a
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• pp.26-27
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• 1994

이산화탄소는 지구 온난화를 일으키는 대표적인 온실 기체로 알려져 왔으며 이에 따라 고온의 배가스에서 이산화탄소를 효율적으로 분리해 낼수 있는 기술이 국가 산업적 필요성을 갖게 되었다. 막을 이용한 기체 분리 기술은 낮은 가격, 비교적 간단한 공정상의 잇점 등 때문에 많은 관심을 끌고 있는 분리 기술이며, 특히 무기막은 열적, 화학적 안정성 등의 장점으로 인해 혹독한 조건에의 응용이 가능하다. 본 연구에서는 다공성 지지체에 염을 함침시킨 무기막(Immmobilized Salt Membrane)을 제조하여 기체 분리 특성을 조사하였다.

• Proceedings of the Membrane Society of Korea Conference
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• 2005.11a
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• pp.291-294
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• 2005

• Membrane Journal
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• v.33 no.4
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• pp.222-232
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• 2023

In this study, a hollow fiber support membrane was prepared by a non-solvent induced phase separation (NIPS) method using a polysulfone (PSf). The prepared hollow fiber support membrane was coated with PDMS and Pebax to prepare a hollow fiber composite membrane. The prepared composite membrane was measured for permeance and selectivity for pure CO₂, H₂, O₂ and N₂. Gas separation performance of the module having the highest selectivity (CO₂/H₂) among the prepared composite membrane modules was measured according to the change in stage cut using simulated gas. The composition of the simulated gas used at this time was 70% CO₂ and 30% H₂. In the 1 stage experiment, it was possible to obtain values of about 60% of H₂ concentration and 12% of H₂ recovery. In order to overcome the low H₂ concentration and recovery, 2 stage serial test was performed, and through this, it was possible to achieve 70% H₂ concentration and 70% recovery. Through this, it was possible to derive a separation process configuration for CO₂/H₂ separation.

• KSBB Journal
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• v.22 no.3
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• pp.174-178
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• 2007

The aim of this study was to identifyisothiocyanates (ITCs) from wasabi (Wasabi japonica Matsum) using supercritical carbon dioxide ($SCO_2$) and to compare the composition in the extracts between $SCO_2$ and organic solvents extraction. A semi-continuous high pressure apparatus was used to extract wasabi (roots, stems and leaves) at following conditions pressure 80$\sim$120 bar, temperature $40\sim50^{\circ}C$. Ether, ethanol, chloroform and dichloromethane were used as organic solvents. The ITCs extracted by means of both separation technologies were analyzed by a gas chromatography system. As the results of study, AITC and ITCs were highly extracted at 40$^{\circ}C$ and 80 bar. To extract AITC from wasabi, $SCO_2$ extraction is more effective than organic solvents extraction, resulted in thermal degeneration and remaining of organic solvents.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.7
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• pp.4698-4706
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• 2014

In this study, the simulation was performed for the CO removal process using a composite membrane in DME production. The composite membrane, PEI-PDMS (polyetherimide- polydimethyl siloxane) manufactured by Airrane Co. Ltd., was used in the modeling through a commercial simulation design program, PRO/II with PROVISION 9.2 by Invensys. To simulate the process, the permeability constants of each of the pure component from Airrane Co. Ltd. were determined by regression analysis from the experimental data. The required separation membrane area and utility cost in the CO removal process were obtained using a chemical process simulator and composite membrane with a compatible permeability constant.