• 멤브레인
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• 제21권2호
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• pp.148-154
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• 2011

금속-세라믹 복합 분리막은 특히 석탄가스화 공정이나 메탄 개질에서 발생되는 혼합가스로부터 수소를 분리하기 위해 개발되어졌다. 수소투과 금속인 팔라듐과 세라믹 지지체로 $Y_2O_3$-stabilized $ZrO_2$ (YSZ)를 이용하여 cermet 수소분리막을 제조하였다. 이렇게 제조된 분리막은 팔라듐의 연속상이 잘 발달된 치밀 구조를 보였다. Pd/YSZ 분리막의 수소 투과량은 100% 수소를 흘려 0.5~2 atm에서 측정되었다. 수소 투과량은 $450^{\circ}C$, 2 atm에서 0.333 mL/$min{\cdot}cm^2$를 보였다. 수소 투과 후 분리막의 표면과 단면에서 균열이 형성되었다.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2012년도 제38회 춘계학술대회논문집
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• pp.100-103
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• 2012

친환경 추진제를 사용하는 추력기의 성능 향상을 위해서 미소량의 연료를 첨가하는 블렌딩 기법을 적용하였다. 친환경 추진제로는 90 wt.% 과산화수소를 사용하였으며, 혼합하는 연료는 에탄올을 사용하였다. 혼합비는 98 wt.% 과산화수소의 이론 성능을 상회하는 성능을 갖는 50으로 정하였다. 실험 결과 에탄올 블렌딩한 과산화수소의 반응기 온도가 과산화수소의 단열 분해 온도보다 높았다. 따라서 에탄올 블렌딩을 통해서 성능 증대를 꾀할 수 있었다. 또한 다양한 촉매 및 지지체의 비교를 통해 에탄올 블렌딩한 과산화수소 분해 및 연소에 적합한 촉매 조합을 파악하였다. 실험 결과 백금 촉매가 적합하다고 판단되며 이산화망간 촉매는 재사용 시 불안정성이 증가하였다. 고온 안정성이 높은 ${\alpha}-Al_2O_3$를 지지체로 사용할 경우 촉매의 분해 성능이 낮아 매우 불안정한 성능을 보였다.

• 한국가스학회지
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• 제27권1호
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• pp.33-37
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• 2023

기후변화 문제를 해결하기 위한 각국의 노력은 계속되고 있고, 친환경 연료로의 전환은 지속적으로 진행해야 할 인류의 과제이다. 국내에서는 최근 재생에너지자원이 비교적 풍부한 제주도에서 재생에너지와 연계한 그린수소를 생산하는 기술을 실증하기 위하여 준비 중이며, 본 연구에서는 국내외 기술현황을 파악 후 해외선진기업의 고분자 전해질 수전해 장치를 도입하여 적용하는 것을 목표로 하고 있다. 본 연구를 진행하면서 국외에서 제작되는 수전해 장치에 대하여 국내안전규제에 부합한 시스템 도입과정과 핵심부품의 평가방법을 소개하고자 한다.

• Journal of Microbiology
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• 제38권2호
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• pp.99-104
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• 2000

Hydrogen peroxide has been used in cleaning the piping of an advanced high-purity water system that supplies ultra-high purity water (UHPW) for 16 megabyte DRAM semiconductor manufacturing. The level of hydrogen peroxide-resistant bacteria in UHPW water was monitored prior to and after disinfecting the piping with hydrogen peroxide. Most of the bacteria isolated after hydrogen peroxide disinfection were highly resistant to hydrogen peroxide. However, the percentage of resistant bacteria decreased with time. The hydrogen peroxide-resistant bacteria were identified as Micrococcus luteus, Bacillus cereus, Alcaligenes latus, Xanthomonas sp. and Flavobacterium indologenes. The susceptibility of the bacteria to hydrogen peroxide was tested as either planktonic cells or attached cells on glass. Attached bacteria as the biofilm on glass exhibited increased hydrogen peroxide resistnace, with the resistance increasing with respect to the age of the biofilm regrowth on piping after hydrogen peroxide treatment. In order to optimize the cleaning strategy for piping of the high-purity water system, the disinfecting effect of hydrogen preoxide and peracetic acid on the bacteria was evaluated. The combined use of hydrogen peroxide and peracetic acid was very effective in killing attached bacteria as well as planktonic bacteria.

• Nuclear Engineering and Technology
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• 제54권4호
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• pp.1288-1294
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• 2022

Hydrogen as an environmentally friendly energy carrier has received special attention to solving uncertainty about the presence of renewable energy and its dependence on time and weather conditions. This material can be prepared from different sources and in various ways. In previous studies, fossil fuels have been used in hydrogen production, but due to several limitations, especially the limitation of the access to this material in the not-too-distant future and the great problem of greenhouse gas emissions during hydrogen production methods. New methods based on renewable and green energy sources as energy drivers of hydrogen production have been considered. In these methods, water or biomass materials are used as the raw material for hydrogen production. In this article, after a brief review of different hydrogen production methods concerning the required raw material, these methods are examined and ranked from different aspects of economic, social, environmental, and energy and exergy analysis sustainability. In the following, the current position of hydrogen production is discussed. Finally, according to the introduced methods, their advantages, and disadvantages, solar electrolysis as a method of hydrogen production on a small scale and hydrogen production by thermochemical method on a large scale are introduced as the preferred methods.

• 한국수소및신에너지학회논문집
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• 제22권1호
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• pp.77-82
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• 2011

In this study, a metal-supported SOFC was fabricated using a relatively cheap and simple process. The adhesion process between ceramic cell and metal support was performed in high temperature over $1400^{\circ}C$ and the deformation of large metal-supported cell happened in this process. Using bi-layered metal support fabricated by diffusion bonding, the deformation of the metal-supported cell can be minimized and the sealing efficiency of anode and cathode was improved. The flatness of the cell was improved by over 20% and the maximum power density of over 0.5 $Wcm^{-2}$ was obtained at the operation condition of $800^{\circ}C$.

• 한국수소및신에너지학회논문집
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• 제28권5호
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• pp.531-535
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• 2017

The performance of all-vanadium redox flow battery (VRFB) was tested with an increase of the current density. APS membrane (anion exchange membrane) and GF050CH (cabon felt) were used as a separator and electrode, respectively. An average energy efficiency of the VRFB was 79.5%, 68.1%, and 62.8% for the current density of $60mA/cm^2$, $120mA/cm^2$, and $160mA/cm^2$, respectively. It was confirmed that VRFB can be used as a energy storage system at the higher current density even if the energy efficiency was deceased about 21%.

• 한국표면공학회지
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• 제55권6호
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• pp.319-327
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• 2022

Ion exchange membranes have been developed from laboratory tools to industrial products with significant technical and trade impacts in the last 70 years. Today, ion exchange membranes are successfully applied for water and energy for different electro-membrane processes. Hydrogen could be produced by electrochemical water splitting using renewable energy, for example, solar, biomass, geothermal and wind energy. This review briefly summarizes the recent studies reporting the state-of-the-art anion-exchange membrane water electrolysis, especially focusing on the enhancement of the durability of anion-exchange membranes. Anion-exchange membrane water electrolysis could be used as inexpensive non-noble metal electrocatalysts that are capable of producing low cost of hydrogen. However, the main challenge of anion-exchange membrane water electrolysis is to increase the performance and durability. In this mini review, the limiting factors of the durability and the technology enhancing the durability will be discussed for anion exchange membrane water electrolysis.

• 한국수소및신에너지학회논문집
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• 제22권5호
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• pp.609-615
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• 2011

A 5 kW class SOFC system for cogeneration power units was consisted of a hot box part and cold BOPs. High temperature components such as a stack, a fuel reformer, a catalytic combustor, and heat exchanges are arranged in the bot box considering their operating temperatures for the system efficiency. The hot box was made of ceramic boards for the thermal insulation. A 5 kW class SOFC stack was composed of 2 sub-modules and each module had 64 cells with $15{\times}15cm^2$ area and stainless steel interconnects. The 5 kW class SOFC system was operated with a hydrogen and a city gas. With a hydrogen, the total power of the stacks was about 7.1 kWDC and electrical efficiency was about 49.3% at 80 A. With a city gas, the total power of the stacks was about 5.7 $kW_{DC}$ and electrical efficiency was about 38.8% at 60 A. Under self-sustained operating condition, the system efficiency including a power conditioning loss and a consumed power by BOPs was about 30.2%.

• 한국수소및신에너지학회논문집
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• 제33권6호
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• pp.616-622
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• 2022

At the present time, interest in hydrogen is increasingly growing worldwide to tackle climate change. Korea also takes an action by announcing the first hydrogen economy implementation basic plan with the import targets of 22.9 million tons of hydrogen from oversea in 2050. To achieve this plan, it is very essential to establish an overseas hydrogen supply chain. In this paper, the study estimates the import price for hydrogen into basic scenario and comprehensive scenario, and also analyses economic feasibility considering price of the each technology.