팔라디움 복합막의 제조 및 응용

남승은,이규호 한국공업화학회 2002 공업화학 Vol.13 No.3

팔라디움(Pd)계 막들은 수소에 대한 선택투과도가 매우 높아서 고온의 혼합 기체 중에서 고순도 수소기체의 분리에 효과적으로 이용되고 있으며 탈수소 반응 등과 연계되어 많은 연구가 이루어져왔다. 순수한 팔라디움 금속 막의 경우 수소를 투과하면 수소농도에 따라 α 상 이외에 β 상이 형성되어 격자 평창에 의한 뒤틀림 현상이 발생하여 부스러지기 쉬우며 이를 보완하기 위해 니켈, 구리, 은 등 다른 금속과의 합금이 반드시 요구된다. 또한 높은 수소투과 속도와 기계적 강도를 함께 유지하기 위해 복합막 형태의 팔라디움 막이 제조되며 복합막 제조시 박막의 핀홀을 최소화하고 장기적 안정성을 유지하는 것이 매우 중요한 문제이다. 이러한 팔라디움 막을 막반응기에 활용함으로써 탈수소 반응이나 수증기 개질 반응 등의 반응효율을 크게 높일 수 있다. 본고에서는 팔라디움 막의 구조 및 수소와 다른 기체투과 메카니즘, 여러 팔라디움 복합막 제조 방법 및 이에 따른 특성 그리고 이들의 응용분야에 대해 살펴보고자 한다. Palladium(Pd) and palladium alloy membranes, which are well-known nonporous membranes with high perm-slectivity of hydrogen, have been used to separate hydrogen of high purity from vatious gas mixtures. The study of these membrane systems as hydrogen separation membranes and membrane reactors has been rather extensive for the past several decades. Pd alloys with other metals such as nickel, copper and silver are preferred over pure Pd, since pure Pd is subject to the α-β phase transformation due to the adsorption of hydrogen, which changes the atom spacing in the metal lattice and becomes brittle after repeated cycles of hydrogen sorption and desorption. For high flux of hydrogen permeation together with mechanical stability, Pd membranes have been mostly composite type structure with thin coating layer over a memchanically strong porous supporting layer. Minimization of pin holes and maintenance of long term stability of thin coating layer are very important factors in the preparation of composit membranes. The reaction effeciency of de-hydrogenation and water vapor reforming reaction was improve by the membrane reactors made with these palladium membranes. In this paper the structure of palladium membranes, the transport mechanism of hydrogen and gases, the preparation and characteristics of various composite palladium membranes and their applications will be discussed.

대기중 이산화탄소 배출 제어를 위한 분리막 기술

서봉국,박유인,이규호 한국화학공학회 2003 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.41 No.4

온실효과에 의한 지구 온난화 현상의 주요 원인이 되는 이산화탄소의 대기중 배출 제어를 위한 대책 기술의 하나로서 에너지 저 소비형 분리막 기술이 최근 주목을 받고 있다. 본 논문에서는 이산화탄소를 효율적으로 분리하기 위한 각종 분리막의 개념을 소개하고, 지금까지 개발된 이산화탄소 분리용 고분자막, 무기막, 중공사 접촉기막을 중심으로 국내외 연구 개발 동향과 향후 연구 전망에 대해서 해설하였다. Membrane separation technology is attracting much attention as an efficient tool for carbon dioxide reduction to migrate the green house effects. In this paper, we introduce concepts of membranes for carbon dioxide separation and review many researches relating to polymeric membranes, inorganic membranes and hollow fiber membrane contactor.

막 접촉기-탈거탑 복합 공정을 이용한 이산화탄소 분리회수

연순화,서봉국,박유인,이규호 한국화학공학회 2001 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.39 No.6

중공사막 접촉기를 기존의 흡수장치에 흡수기로 도입하여 구축한 hybrid 시스템을 이용하여 이산화탄소의 분리·회수에 관한 연구를 수행하였다. 분리효율이 우수한 중공사막 접촉기를 개발하기 위해 다양한 구조적 특성을 가지는 PVDF, PTFE 및 PP 중공사막을 이용하여 혼합 기체 및 흡수제 유량 등의 운전조건에 따른 이산화탄소 제거효율 특성을 조사하였다. 그 결과 중공사막 접촉기가 기존의 충진 흡수탑에 비해 큰 기-액간의 접촉면적으로 인해 분리효율이 높았으며, 그 중에서도 PVDF 중공사 막이 안정된 기-액간의 계면을 유지함으로서 다른 중공사막에 비해 우수한 분리효율을 나타내었다. 또한, 흡수제의 종류(H_2O, K_2CO_3, MEA)에 따른 흡수성능을 조사하고, CO_2-MEA계에서 각 중공사막에 대한 물질전달 특성을 비교하였다. 이산화탄소 분리효율, 경제성, 물질전달 특성 등을 고려하면, MEA를 흡수제로 사용한 경우, PVDF 중공사막이 막 접촉기로서 가장 적합할 것으로 기대된다. Membrane contactor-stripper hybrid process was used to recover CO_2 from the flue gas. Porous PTFE, PVDF, PP hollow fiber modules were used as the membrane contactor. The CO_2 was removed by the porous polymeric hollow fiber membrane contactor using H_2O, K_2CO_3 or monoethanolamine(MEA) solution as the absorbent. Then, the CO_2 was recovered from the absorbent by the thermal stripping tower with steam. The membrane contactor increased the gas-liquid contactor area and mass transfer coefficient, and thus the hybrid process showed a higher CO_2 removal efficiency than the conventional absorption tower. PVDF module with smaller pore size showed the most stable gas-liquid interface and the highest removal efficiency among the hollow fiber membrane contactor modules. gas

온실가스 저감을 위한 국내외 R&D 및 정책 동향

이상훈,서봉국,이규호 한국환경과학회 2004 한국환경과학회지 Vol.13 No.9

Recently many countries agreed to reduce emissions of greenhouse gases into the atmosphere or at least to keep them at the current level at the Kyoto Protocol. Carbon dioxide has been proven to be 80% of greenhouse gases, contributing to the increase of the earth's surface temperature. It is reported that half of the CO₂ emissions are produced by industry and power plants using fossil fuels. In this article, we review and analysis domestic and abroad R&D policy trends relating to UN framework convention on climate change(UNFCCC).

연구발표논문초록 ( 분리기술 (3) )

Kew Ho Lee (정),Sun Tak Hwang (정) 한국화학공학회 1987 추계학술발표회 Vol.- No.-

광촉매 공정에 의한 유기물 제거가 나노여과 공정에 미치는 영향

Kew-Ho Lee,In-Hwan Choi,In-Chul Kim,Byoung-Ryul Min 한국막학회 2007 멤브레인 Vol.17 No.3

광촉매 반응이 자연유기물에 의한 나노여과막의 오염에 미치는 영향을 살펴보았다. 광촉매 분해공정은 자연유기물의 분해와 변형에 효율적이었으며 이산화티타늄과 고정화 비드를 광촉매로 사용하였다. 광촉매적 특성을 비교하기 위하여 칼슘 이온 존재 시의 휴민산의 광분해를 모델 반응으로 설정하였다. 광분해 전에는 치밀한 막오염층이 형성되어 막오염을 가속화시킨 반면, 광분해 후에는 막오염이 크게 감소하였다. This research investigated the effect of a photocatalytic reaction on nanofiltration(NF) membrane fouling by natural organic matter(NOM). The photocatalytic degradation was very effective for destruction and transformation of NOM and was carried out by titanium dioxide(TiO2) and TiO2-immobilized bead as a photocatalyst. In order to compare their phtocatalytic properties, the photocatalytic degradation of humic acid in the presence of calcium ion was used as a model reaction. After the photocatalytic degradation the membrane fouling was dramatically decreased.

Preparation of Fouling Resistant Nanofiltration and Reverse Osmosis Membranes and Their use for Dyeing Wastewater Effluent

Kew-Ho Lee,In-Chul Kim,Young-Hyun Ka,Joo-Young Park 한국공업화학회 2004 Journal of Industrial and Engineering Chemistry Vol.10 No.1

Flow of gases through microporous membrane

( Kew Ho Lee ) 한국화학공학회 1987 추계학술발표회 Vol.1987 No.-

Preparation of a Water-Selective Ceramic Membrane on a Porous Stainless Steel Support by Sol-Gel Process and Its Application to Dehydration Membrane Reactor

Lee, Kew-Ho,Sea, Bongkuk,Youn, Min-Young,Lee, Yoon-Gyu,Lee, Dong-Wook The Membrane Society of Korea 2004 Korean Membrane Journal Vol.6 No.1

We developed a water-selective ceramic composite membrane for use as a dehydration membrane reactor for dimethylether (DME) synthesis from methanol. The membranes were modified on the porous stainless steel support by the sol-gel method accompanied by a suction process. The improved membrane modification process was effective in increasing the vapour permselectivity by removal of defects and pinholes. The optimized alumina/silica composite membrane exhibited a water permeance of 1.14${\times}$10$^{-7}$ mol/$m^2$.sec.Pa and a water/methanol selectivity of 8.4 at permeation temperature of 25$0^{\circ}C$. The catalytic reaction for DME synthesis from methanol using the membrane was performed at 23$0^{\circ}C$, and the reaction conversion was compared with that of the conventional fixed-bed reactor. The reaction conversion of the membrane reactor was much higher than that of the conventional fixed-bed reactor. The reaction conversion of the membrane reactor and the conventional fixed-bed reactor was 82.5 and 68.0%, respectively. This improvement of reaction efficiency can last if the water vapour produced in the reaction zone is removed continuously.

Modification of Polysulfone Membranes and Their Application to Gas Separations

Lee, Kew Ho,Park, You In,Kim, Jung Ran,Rhim, Ji Won 한국공업화학회 2001 Journal of Industrial and Engineering Chemistry Vol.7 No.5

The surface of polysulfone membranes has been modified using the fluorine chemicals, PFPA (pentafluoropropionic anhydride F.W.=310.05) and TFI (Trideca-fluoro-8-idoctane, F.W.=474.0), based on Friedel-Crafts reaction mechanism with varying reaction temperatures, reaction time, and catalysis types. The resulting membranes were characterized through the analysis of ESCA, contact angle measurement and pure water permeability. And the modified PS membranes were exposed to gases of O₂, N₂, and CO₂ to measure the permeation rates and ideal separation factors. In addition, the diffusivities and solubilities of individual gases were measured.