• Proceedings of the Membrane Society of Korea Conference
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• 1995.04a
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• pp.58-59
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• 1995

기체 분리용 무기분리막은 고분자막과 비교하여 열 및 구조적 안정성이 우수하므로, 석탄가스화반응 혼합기체중의 기체분리 등 고온 또는 고압공정에 적합한 분리방법으로서 주목되고 있다. 기체의 분리를 위한 무기재료막은 크게 다공성막과 비다공성막으로 나눌 수 있으며, 이 중 비기공 성막의 경우 높은 선택도를 가지나 투과도가 낮아 경제성이 떨어지는 것으로 평가되고 있다. 한편, 기존의 다공성막의 경우 투과도는 높으나 기체의 분리가 혼합기체중 각 기체의 분자량의 차이에 의존하는 Knudsen 확산에 제한되는 낮은 선택도를 갖는 단점이 있다. 따라서 다공성막의 기공을 특정기체의 선택도가 우수한 촉매물질등으로 개선하여 비기공성막에 비해 우수한 투과도를 갖고, 기공성막에 비해 향상된 선택도를 보이는 복합막의 연구가 활발히 추진되고 이\ulcorner. 본 연구는 솔젤법에 의해 제조된 팔라듐 함침 알루미나 지지막의 기공을 침투$\cdot$증착(Soaking and Vapor-deposition)법에 의해 개선하여 기체의 투과도를 높게 유지하면서 수소의 선택성을 향상시키는 것을 목적으로 하였다.

• Journal of the Korean Applied Science and Technology
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• v.37 no.5
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• pp.1106-1115
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• 2020

Research was conducted on the production of bio-methane for city gas, from food waste digestion gas using two membrane-separation methods(4SBR and 3SDR) in a commercial plant. A purity of 98.9% can be obtained using either method. The recovery rate of methane from the digestion gas was 88.1% for 4SBR and 79.4% for 3SDR. the ratios of bio-methane production to treated digestion gas were 53.5% for 4SBR and 49.4% for 3SDR. However, the 4SBR method had a higher ratio of returned gas(56.5%), approximately twice that of 3SDR, making 3SDR the more desirable method in terms of maximum treat capacity. Therefore, 4SBR seems more economical when the digestion gas to be treated is less than 200 N㎥/day, while 3SDR is more suited to treat gas volumes of more than 240 N㎥/day. The relative deviation of each operation index, compared to mean values, was generally greater for the 4SBR method. Additionally, the correlation coefficients between major system indexes, such as bio-methane production and bio-methane draw out pressure(which is the main control measure of membrane facility) showed that these indexes are more closely related in the 3SDR method.

• Korean Chemical Engineering Research
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• v.43 no.2
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• pp.222-229
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• 2005

Five stage enriching membrane system for separating combustion gas (air 90%, $CO_2$ 10%) was proposed and simulated by using Aspen plus and Excel. The system recovers 90% $CO_2$ of the combustion gas and the purity of $CO_2$ recovered was more than 99%. Optimization yields a reduction in membrane area as well as operating and capital cost. Retentate concentration and permeate pressure of each stage were chosen as optimization variables. By analyzing the optimization results, we derived several design guide lines for the enriching membrane system.

• Membrane Journal
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• v.14 no.1
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• pp.66-74
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• 2004

Total resistance of membrane in a micro-filtration system using a metal membrane was mainly attributed to the permeate resistance of cake layer($R_c$), which was formed by deposited particles from the physico-chemical interactions of solids on membrane surface. Intermittent back ozonation was highly effective than the air backwashing for fouling reduction. As far the operational effect, under same ozone injection, the increase of gas flow-rate was more favorable than the increase of injection time far the recovery of permeation flux. As the filtration time was longer, the effect of flux recovery by intermittent back-ozonation decreased. Therefore, it is preferable to operate membrane cleaning before the foulant is consolidated on membrane surface.

• Membrane Journal
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• v.31 no.4
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• pp.268-274
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• 2021

One of the chronic problems in the issue of global warming is the emission of greenhouse gases. Carbon dioxide (CO₂), which accounts for the highest proportion of various greenhouse gases, has been continuously researched by humans to separate it. From this point of view, a poly(vinyl alcohol) (PVA)-based copolymer with acrylic acid monomer was utilized in a gas separation membrane in this study. We employed a free radical polymerization to fabricate PVA-g-PAA (VAA) graft copolymer. It was utilized in the form of a composite membrane on a polysulfone substrate. The proper amount of acrylic acid reduced the crystallinity of PVA and increased CO₂ solubility in separation membranes. In this perspective, we suggest the novel approach in CO₂ separation membrane area by grafting and solution-diffusion.

• Applied Chemistry for Engineering
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• v.16 no.2
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• pp.282-287
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• 2005

Palladium membranes, which are permselective to hydrogen separation, were used for the hydrogen purification and in membrane reactors for improving conversions by shifting the reaction equilibrium. Palladium/ceramic composite membranes were prepared by electroless plating technique and then etched in titanium chloride ($TiCl_4$) as a post treatment to enhance the membrane's durability. These membranes were used for membrane reactors in water gas shift (WGS) reaction. CO conversions for the membrane reactor were obtained according to experimental parameters and compared to the traditional reactor without a palladium/ceramic membrane. As a result, CO conversion using palladium membrane reactor at an appropriate condition was over 20~25% greater than that without the membrane reactor. The stability in the long-term test of up to 120 h for WGS reaction with the membrane reactor was good without the degredation of CO conversion.

• Journal of the Korean Institute of Gas
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• v.10 no.2 s.31
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• pp.14-21
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• 2006

An experimental apparatus for the removal of $SO_2$ gas using microporous hollow-fiber membrane G-L contactors was setup. Various performance experiments were carried out with commercial membrane modules and the membrane modules made by KIER. The $SO_2$ removal efficiency was outstanding. When the hollow-fiber membrane was used for the removal of $SO_2$, the selection of absorbers and additives, membrane material, operating conditions of membrane manufacture were significant variables to develop optimal G-L contactors. More experiment works will be done for the development of compact, cost-effective and better G-L contactors.

• Applied Chemistry for Engineering
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• v.21 no.4
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• pp.475-478
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• 2010

Fluorinated polymeric membranes were prepared by direct surface modification of PDMS with fluorine gas ($50{\sim}2000\;{\mu}mol/mol$ in nitrogen). The formed fluorinated polymeric membranes were characterized by FT-IR spectroscopy, GC (Gas chromatography), atomic force microscopy, and scanning electron microscopy. Direct fluorination resulted in the change of permeability and selectivity of various gases (pure gases such as $CO_2$, $O_2$, $N_2$, $C_2H_4$, mixture of He, Ne, Kr, Xe) through PDMS membranes. Fluorination resulted in the maximum 50% increase of selectivity through PDMS membrane.

• Membrane Journal
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• v.20 no.4
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• pp.267-277
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• 2010

Gas separation membranes have been developed for decades in various areas to replace the conventional processes. Membrane processes for gas separation have many advantages of energy saving, compact size, and easy scale-up. Nowadays, gas separation processes is widely spreaded in nitrogen generating system, hydrogen generating system, membrane dryer, on board inert gas generating system, natural gas purification, biogas purification and fuel cells. Carbon dioxide separation process using membrane would be a strong candidate of carbon dioxide capturing process. In order to broaden the scope of application of gas separation membranes, development of new materials which can overcome the borderline of Robeson's plot should be necessary, so that many researchers and companies are trying to develop the new materials like polymers containing cardo and spiro group and PIMs (polymers for intrinsic microporosity).

• Membrane Journal
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• v.33 no.6
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• pp.305-314
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• 2023

Various methods for removing by-products from chemical reactions are being studied to improve yield of catalytic reaction. Since the water is predominantly generated as a by-product in industrially significant reactions, it is necessary to develop the technology that can reliably remove water over a wide range of temperatures. Although several strategies using absorbents and additional dehydration reactions, have been proposed, they have limitations due to the issues such as additional energy and time consuming steps and sustainability of conversion. Membrane technology, which offers advantages such as easy operation, installation, and low maintenance costs, proves to be a promising approach for enhancing the efficiency of catalysts in various catalytic reactions. Therefore, this review discusses the removal of by-products using membranes and the associated benefits in this context.