• 기술사
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• 제45권6호
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• pp.20-27
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• 2012

World has become interested in the development of new dean energy because of oil prices rise and global warming due to carbon dioxide emissions. This study evaluated the safety of the refueling infrastructure for hydrogen, CNG and HCNG(hydrogen blended natural gas) which recently take center stage as a clean fuel. The risk of fuel was evaluated by 3D computational fluid dynamics program for gas dispersion and explosion. Hydrogen is higher than the CNG explosion overpressure and shows rapid spread. On the other hand, CNG and 30% HCNG showed quite similar characteristics. HCNG slightly rises in risk than the CNG, but HCNG is safe compared to hydrogen.

• 한국수소및신에너지학회논문집
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• 제22권1호
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• pp.29-34
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• 2011

This study examined the effect of environmental variables, such as the NaOH concentration and solution temperature, on the rate of hydrogen generation from NaOH solutions through the corrosion of used aluminum cans as a potential candidate material for the safe and economic production of hydrogen. Corrosion of the used aluminum cans was promoted by increasing the NaOH concentration and solution temperature because of the loss of aluminum passivity. The measured rate of hydrogen generation from the NaOH solutions increased with increasing NaOH concentration due to the catalytic activity of NaOH in the hydrolysis process. However, at higher solution temperatures, the rate of hydrogen generation rate was less affected by the NaOH concentration than that at lower temperature.

• International Journal of Internet, Broadcasting and Communication
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• 제16권2호
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• pp.255-266
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• 2024

The purpose is to evaluate evacuation safety by simulating the toxic effects of hydrogen fluoride leaks in areas surrounding national industrial complexes and to suggest alternatives for areas that do not satisfy evacuation safety. For human casualties caused by hydrogen fluoride leakage accidents, Available Safe Egress Time (ASET) is calculated by the toxic effects quantified with the Areal Locations of Hazardous Atmospheres (ALOHA), an off-site consequence assessment program. The Required Safe Egress Time (RSET) is calculated through Pathfinder, an evacuation simulation program. Evacuation safety is assessed by comparing ASET and RSET. The ALOHA program was used to evaluate the time to reach AEGL-2 concentration in 12 scenarios. The Pathfinder program was used to assess the total evacuation time of the high school among specific fire-fighting objects. Of the 12 accident scenarios, ASET was larger than RSET in the worst-case scenarios 1 and 9. For the remaining 10 accident scenarios, the ASET is smaller than the RSET, so we found that evacuation safety is not guaranteed, and countermeasures are required. Since evacuation safety is not satisfactory, we proposed to set up an evacuation area equipped with positive pressure equipment and air respirators inside specific fire-fighting objects such as the high school.

• International Journal of Advanced Culture Technology
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• 제3권2호
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• pp.87-99
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• 2015

Fast depletion of fossil fuels is urgently demanding a carry out work for research to find out the viable alternative fuels for meeting sustainable energy demand with minimum environmental impact. In the future, our energy systems will need to be renewable and sustainable, efficient and cost-effective, convenient and safe. Hydrogen is expected to be one of the most important fuels in the near future to meet the stringent emission norms. The use of the hydrogen as fuel in the internal combustion engine represents an alternative use to replace the hydrocarbons fuels, which produce polluting gases such as carbon monoxide (CO), hydro carbon (HC) during combustion. In this paper contemporary research on the hydrogen-fuelled internal combustion engine can be given. First hydrogen-engine fundamentals were described by examining the engine-specific properties of hydrogen and then existing literature were surveyed.

• 한국가스학회지
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• 제12권2호
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• pp.1-6
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• 2008

대부분의 가스공정의 안전한 설계와 조작을 위해서는 취급물질의 확실한 폭발한계, 인화점, 최소자연 발화온도, 최소산소농도 등을 알아야하고, 또한 고온 및 고압에서의 폭발한계도 알아야 한다. 본 연구에서는 수소의 안전한 취급을 위해 수소의 연소특성치인 폭발한계와 최소자연발화온도를 고찰하였다. 문헌자료를 고찰한 결과 수소의 폭발하한계와 상한계는 공기 중에서 4.0 vol%와 77.0 vol%를 추천하고, 최소 자연발화온도는 전면 가열인 경우는 $400^{\circ}C$, 국소 고온표면인 경우는 $640^{\circ}C$를 추천한다. 또한 수소의 폭발한계의 온도 및 압력의존성에 대한 새로운 예측식을 제시하였으며, 제시된 식에 의한 예측값은 문헌값과 일치하였다.

• 한국안전학회지
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• 제36권4호
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• pp.71-79
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• 2021

In this study, a real-scale fuel-cell room of volume 1.36 m³ is constructed to confirm the explosion characteristics of hydrogen-air mixture gas in a hydrogen-powered house. A volume concentration of 40% is applied in the fuel-cell room as the worst-case scenario to examine the most severe accident possible, and two types of doors (made of plastic sheet and wood) are fabricated to observe their effects on the overpressure and impulse. The peak overpressure and impulse based on distance from the ignition source are experimentally observed and assessed. The maximum and minimum overpressures with a plastic-sheet door are about 20 and 6.7 kPa and those with a wooden door are about 46 and 13 kPa at distances of 1 and 5 m from the ignition source, respectively. The ranges of impulses for distances of 1-5 m from the ignition source are about 82-28 Pa·s with a plastic-sheet door and 101-28 Pa·s with a wooden door. The amount of damage to people, buildings, and property due to the peak overpressure and impulse is presented to determine the safe distance; accordingly, the safe distance to prevent harm to humans is about 5 m based on the 'injuries' class, but the structural damage was not serious.

• Nuclear Engineering and Technology
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• 제39권1호
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• pp.1-8
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• 2007

Hydrogen and electricity are expected to dominate the world energy system in the long term. The world currently consumes about 50 million metric tons of hydrogen per year, with the bulk of it being consumed by the chemical and refining industries. The demand for hydrogen is expected to increase, especially if the U.S. and other countries shift their energy usage towards a hydrogen economy, with hydrogen consumed as an energy commodity by the transportation, residential and commercial sectors. However, there is strong motivation to not use fossil fuels in the future as a feedstock for hydrogen production, because the greenhouse gas carbon dioxide is a byproduct and fossil fuel prices are expected to increase significantly. An advanced reactor technology receiving considerable international interest for both electricity and hydrogen production, is the modular helium reactor (MHR), which is a passively safe concept that has evolved from earlier high-temperature gas-cooled reactor (HTGR) designs. For hydrogen production, this concept is referred to as the H2-MHR. Two different hydrogen production technologies are being investigated for the H2-MHR; an advanced sulfur-iodine (SI) thermochemical water splitting process and high-temperature electrolysis (HTE). This paper describes pre-conceptual design descriptions and economic evaluations of full-scale, nth-of-a-kind SI-Based and HTE-Based H2-MHR plants. Hydrogen production costs for both types of plants are estimated to be approximately $2 per kilogram.

• International Journal of Safety
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• 제6권1호
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• pp.16-21
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• 2007

Carbon nanotubes hold much promise as future materials for safe storage of hydrogen. In this paper, hydrogen transport mechanisms in single-walled carbon nano-tubes (SWNTs) for various temperatures and chiral indices were studied using molecular dynamics simulation method. The SWNT models of zigzag (10,0), chiral (10,5) and armchair (10,10) with hydrogen molecules inside were simulated at temperatures ranging from 253K to 373K. Movements of hydrogen molecules ($H_2$) inside a SWNT were analyzed using mean-square displacements and velocity autocorrelation functions.

• Journal of Electrochemical Science and Technology
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• 제12권3호
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• pp.302-307
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• 2021

Polymer electrolyte membrane (PEM) electrolyzer or alkaline electrolyzer is required to produce green hydrogen using renewable energy such as wind and/or solar power. PEM and alkaline electrolyzer differ in many ways, instantly basic materials, system configuration, and operation characteristics are different. Building an optimal water hydrolysis system by closely grasping the characteristics of each type of electrolyzer is of great help in building a safe hydrogen ecosystem as well as the efficiency of green hydrogen production. In this study, the basic operation characteristics of a kW class alkaline water electrolyzer we developed, and water electrolysis efficiency are described. Finally, a brief overview of the characteristics of PEM and alkaline electrolyzer for large-capacity green hydrogen production system will be outlined.

• 한국수소및신에너지학회논문집
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• 제33권3호
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• pp.240-246
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• 2022

This study was conducted to develop a domestic product for a flow control valve for a hydrogen refueling station, and a domestic prototype was manufactured and the durability performance evaluation was conducted through comparison with an imported products. The stress generated by the internal pressure was checked and safety was confirmed using a commercial structural analysis program, ABAQUS, in accordance with the withstand pressure test standards. In addition, after identifying the weak areas the fatigue life was predicted through a commercial software, fe-safe. This fatigue analysis showed that the hydrogen gas repeated test criteria were satisfied.