• Membrane Journal
• /
• v.17 no.2
• /
• pp.81-92
• /
• 2007

Membrane-based separation processes are receiving increasing attention in the scientific community and industry since they provide a desirable alternative to processes that are not easy to achieve by conventional separation technologies. In particular, gas separation using polymeric membranes have annually grown so fast owing to advantages such as easy installation, no moving parts, small footprint and low energy process. The key element is definitely a polymer membrane exhibiting high permeability and high selectivity to compete with other gas separation technologies. Current polymer membranes used for commercial gas separation are a family of hydrocarbon polymers for hydrogen separation, air separation and carbon dioxide separation from natural gas sweetening. Relatively, gas or vapor separation properties of fluoropolymers are not known so much as compared with those of hydrocarbon polymers. Accordingly, in this study, membranes prepared from amorphous perfluoropolymers are of particular interest because of the unique properties of these polymers. The advantages offered by these amorphous perfluoropolymers for use in gas and vapor separation will be discussed. In addition, membrane properties and separation performance will be compared with other membranes available on the market.

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

• Journal of the Korean Society of Industry Convergence
• /
• v.25 no.6_3
• /
• pp.1247-1260
• /
• 2022

The steel industry accounts for about 5% of the total annual global energy consumption and more than 6% of the total anthropogenic carbon dioxide emissions. Therefore, there is a need to increase energy efficiency and reduce greenhouse gas emissions in these industries. The utilization of coke oven gas, a byproduct of the coke plant, is one of the main ways to achieve this goal. Coke oven gas used as a fuel in many steelmaking process is a hydrogen-rich gas with high energy potential, but it is commonly used as a heat source and is even released directly into the air after combustion reactions. In order to solve such resource waste and energy inefficiency, several alternatives have recently been proposed, such as separating and refining hydrogen directly from coke oven gas or converting it to syngas. Therefore, in this study, recent research trends on the separation and purification of hydrogen from coke oven gas and the production of syngas were introduced.

• Membrane Journal
• /
• v.33 no.4
• /
• pp.168-180
• /
• 2023

H₂ generation from renewable sources is crucial for ensuring sustainable production of energy. One approach to achieve this goal is biohydrogen production by utilizing renewable resources such as biomass and microorganisms. In contrast to commercial methods, biohydrogen production needs ambient temperature and pressure, thereby requiring less energy and cost. Biohydrogen production can reduce greenhouse gas emissions, particularly the emission of carbon dioxide (CO₂). However, it is also associated with significant challenges, including low hydrogen yields, hydrodynamic issues in bioreactors, and the need for H₂ separation and purification methods to obtain high-purity H₂. Various technologies have been developed for hydrogen separation and purification, including cryogenic distillation, pressure-swing adsorption, absorption, and membrane technology. This review addresses important experimental developments in dense polymeric membranes for biohydrogen purification.

• Proceedings of the Korea Society for Energy Engineering kosee Conference
• /
• 2010.04a
• /
• pp.172-172
• /
• 2010

• Membrane Journal
• /
• v.14 no.2
• /
• pp.99-107
• /
• 2004

Carbon molecular sieve (CMS) membranes were prepared by pyrolysis of polyimides having carboxylic acid groups and applied to the hydrogen separation. The polymeric membranes having carboxylic acid groups showed different steric properties as compared with polymeric membranes having other side groups ($-CH_3$ and $-CF_3$) because of the hydrogen bond between the carboxylic acid groups. However, the microporous CMS membranes were significantly affected by the decomposable side groups evidenced from the wide angle X-rat diffraction, nitrogen adsorption isotherms, and single gas permeation measurement. Furthermore, the gas separation properties of the CMS membranes were essentially affected by the pyrolysis temperature. As a result, the CMS membranes Prepared by Pyrolysis of polyimide containing carboxylic acid froups at $700^{\circ}C$ showed the $H_2$ permeability of 3,809 Baller [$1{\times}10^{-10}$ H $\textrm{cm}^$(STP)cm/$\textrm{cm}^2$.s.cmHg], $H_2$/$N_2$, selectivity of 46 and $H_2$/$CH_4$ selectivity of 130 while the CMS membranes derived from polyimide showed the H$_2$ permeability of 3,272 Barrer, $H_2$/$N_2$ selectivity of 136 and $H_2$/$CH_4$ selectivity of 177.

• Proceedings of the Membrane Society of Korea Conference
• /
• 2004.05b
• /
• pp.106-109
• /
• 2004

원자력의 고온가스로(HTGR)의 열원에서 약 1,00$0^{\circ}C$의 열을 이용하여 물을 분해하는 열화학적 수소제조 IS 프로세스는 다음과 같은 3단계 화학반응식에 의해 수소를 제조한다. 이들 화학반응의 수행과정을 반응온도와 공정에 따라 도식화하면 Fig. 1과 같은 3가지 공정으로 구성된다.(중략)

• Proceedings of the Membrane Society of Korea Conference
• /
• 1998.10a
• /
• pp.73-74
• /
• 1998

1. Introduction : We have researched to separate water effectively from aqueous pyridine solution. In our previous papers, we have proposed new separation mechanism, in-situ complex, which is different from solution-diffusion and accelerated transport by hydrogen bonding. We have adopted in-situ complex mechanism to membranes containing phosphoric acids as well as acrylic acid and sulfonic acid in copolymer for dehydration of pyridine.

• Journal of the Korean institute of surface engineering
• /
• v.48 no.1
• /
• pp.11-22
• /
• 2015

Pd alloy hydrogen membranes for hydrogen purification and separation need thermal stability at high temperature for commercial applications. Intermetallic diffusion between the Pd alloy film and the porous metal support gives rise to serious problems in long-term stability of Pd alloy membranes. Ceramic barriers are widely used to prevent the intermetallic diffusion from the porous metal support. However, these layers result in poor adhesion at the interface between film and barrier because of the fundamentally poor chemical affinity and a large thermal stress. In this study, we developed Pd alloy membranes having a dense microstructure and saturated composition on modified metal supports by advanced DC magnetron sputtering and heat treatment for enhanced thermal stability. Experimental results showed that Pd-Cu and Pd-Ag alloy membranes had considerably enhanced long-term stability owing to stable, dense alloy film microstructure and saturated composition, effective diffusion barrier, and good adhesive interface layer.

• Journal of Electrochemical Science and Technology
• /
• v.8 no.3
• /
• pp.183-196
• /
• 2017

The research efforts directed at advancing water electrolysis technology continue to intensify together with the increasing interest in hydrogen as an alternative source of energy to fossil fuels. Among the various water electrolysis systems reported to date, systems employing a solid polymer electrolyte membrane are known to display both improved safety and efficiency as a result of enhanced separation of products: hydrogen and oxygen. Conducting water electrolysis in an alkaline medium lowers the system cost by allowing non-platinum group metals to be used as catalysts for the complex multi-electron transfer reactions involved in water electrolysis, namely the hydrogen and oxygen evolution reactions (HER and OER, respectively). We briefly review the anion exchange membranes (AEMs) and electrocatalysts developed and applied thus far in alkaline AEM water electrolysis (AEMWE) devices. Testing the developed components in AEMWE cells is a key step in maximizing the device performance since cell performance depends strongly on the structure of the electrodes containing the HER and OER catalysts and the polymer membrane under specific cell operating conditions. In this review, we discuss the properties of reported AEMs that have been used to fabricate membrane-electrode assemblies for AEMWE cells, including membranes based on polysulfone, poly(2,6-dimethyl-p-phylene) oxide, polybenzimidazole, and inorganic composite materials. The activities and stabilities of tertiary metal oxides, metal carbon composites, and ultra-low Pt-loading electrodes toward OER and HER in AEMWE cells are also described.