• Journal of the Korean Institute of Gas
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• v.25 no.6
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• pp.53-65
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• 2021

While the hydrogen refueling station is rapidly expanded and installed, the safety inspection of the hydrogen pressure vessel in the station should be very important. Of these, according to ASME, hydrogen embrittlement tests must be performed for hydrogen vessel that store hydrogen above a certain pressure. The main test method for hydrogen embrittlement inspection is to carry out fracture tests and fatigue fracture tests in a high pressure hydrogen atmosphere, which allows the durability limit of the pressure vessel to be measured and the endurable limit to be determined in the hydrogen atmosphere. In detail, the critical crack depth can be calculated by the stress intensity factor(K), and the service life can be determined by da/dN (fatigue growth rate). API579-1/ ASME FFS-1 part 9 exemplifies the calculation method according to the mode of crack-like flaws, but for various shapes such as plates and cylinders, there are about 55 modes according to the shape and location of the crack. Due to the fairly complex formula, it is not easily accessible. In this study, we will show you how to calculate fracture mechanics numerically via Excel and VBA. In addition, this was applied to analyze the effects of the thickness and inner diameter of the pressure vessel on the service life.

• Journal of Hydrogen and New Energy
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• v.34 no.2
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• pp.162-168
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• 2023

The fast refueling process of compressed hydrogen has an important impact on the filling efficiency and safety. With the development and use of hydrogen energy, the demand for precision measurement of filling hydrogen thermodynamic parameters is also increasing. In this paper, the compressibility factor calculation model of high-pressure hydrogen gas was studied, and the basic equation of state and thermo-physical parameters were calculated. The hydrogen density data provided by the National Institute of Standards and Technology was compared with the calculation results of each model. Results show that at a pressure of 0.1-100 MPa and a temperature of 233-363 K, the calculation accuracy of the Zheng-Li equation of state was less than 0.5%. In the range of 0.1-70 MPa, the accuracy of Redich-Kwong equation is less than 3%. The hydrogen pressure more influences on the compressibility factor than the hydrogen temperature does. Using the Zheng-Li equation of state to calculate the compressibility factor of on-board high pressure hydrogen can obtain high accuracy.

• Journal of the Mineralogical Society of Korea
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• v.5 no.2
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• pp.72-78
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• 1992

The Earth outer core accomodates moderately considerable amount of lighter elements than pure iron itself. Hydrogen is one of the possible candidates of minor constituents in the outer core. It would be worth while to extend for the pressure effect on the solubility of hydrogen in the metal-hydrides including iron hydride. In view of hydrogen being one of the potential substitutes for petroleum, searching a more efficient way for storing hydrogen in the form of hydrides is of considerable value. For two purposes, $TiH_2$was selected among lot of hydrides for its characteristics under pressure and temperature. There have been two kinds of experiment carried out on $TiH_2$ under different experimental conditions. As one of these attempts, polycrystalline $TiH_2$ was loaded up to 15 GPa stepwise at the constant temperature 500${\circ}$ using a piston-cylinder diamond anvil cell equipped with a miniature furnace of an electric power supply. The X-ra diffraction technique was employed on the quenched samples after the simultaneous high pressure and temperature treatments. During these high pressure-temperature runs, and irreversible phase of $TiH_2$ has been observed at the pressures higher than 11.3 GPa, which would be assigned to the orthorhombic crystal system as one of the new phase(s) of $TiH_2$. Molar volume change on this phase transition is ∼10%.

• Journal of the Korean Institute of Gas
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• v.28 no.2
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• pp.32-37
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• 2024

Recently, transportations using hydrogen energy is being researched for the alternative energy of fossil fuels. To use them, processes of producing, storing and transferring are required. When carrying them in liquid under 90 MPa pressure, it costs less than in a gas status. Thus, a hydrogen pump is necessary and in this research we predicted the flow in the chamber using finite element methods (FEM) program ANSYS. As a result, when the valve was opened by 3 mm, between the 1^st chamber and the 2^nd chamber, the maximum velocity was decreased to 8.111 m/s by 10.6% (without valve, 9.075 m/s). In addition, pressure was also increased to 0.63 MPa by 1.6% (without valve, 0.62 MPa). When using these results, more efficient processes would be possible in designing them in detail.

• Journal of Hydrogen and New Energy
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• v.16 no.3
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• pp.253-261
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• 2005

석유 연료 고갈 해결 및 온실 효과 가스 배풀 저감을 위한 방안으로 제시되는 수소는 다양한 에너지 저장체로 사용되어 질 수 있으나 안전성에 대한 연구가 요구되어진다. 따라서, 일반적인 저장 형태인 고압 저장 탱크에서 누출이 되었을 경우 분사되는 수소의 거동에 대한 연구가 이루어져야하며 이를 바탕으로 한 보완책이 제시되어야 한다. 이번 연구에서는 누설 시 확산되는 수소의 밀도를 실제 거동과 유사한 3차원 컴퓨터 영상장으로 합성한 후 ART(algebraic reconstruction technique) 및 MART(multiplicative ART)를 기반으로 한 3차원 디지털 스페클 토모그래피 기법을 개발하여 재건하고 분석하였다.

• Journal of the Korean Institute of Gas
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• v.23 no.2
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• pp.9-16
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• 2019

The frequency of major accidents which has probability of occurrence at the high pressure underground pipeline of industrial estate such an Ulsan, Yeo-ju by the other construction such as an excavation work will be compared to city gas underground pipeline to derive the basic event by the FTA and present. Also, Observe and analyze the pipe damage impact factor such as an excavation frequency, patrol cycle. As a result, It contributes to the safety improvement of high pressure gas buried pipeline due to obtain importance and sensitivity of the pipe damge impact factors.

• 한국신재생에너지학회:학술대회논문집
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• 2007.11a
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• pp.462-465
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• 2007

석탄가스화 수소생산 기술 분야는 석탄 등의 화석연료를 이용하여 고온, 고압하에서 반응가스(산소, 수증기, 수소)와의 화학적 반응을 통해 생산된 연소성 가스 ($H_2$, CO, $CO_2$ 등)를 전환반응(WGS) 및 분리반응을 거쳐 효율적으로 청정하게 수소를 생산해 내는 기술이다. 전력산업에서 석탄가스화 수소생산은 그 사용 방법(연료전지, 수소 터빈, 분산 이용 등)에 따라 발전시스템의 고효율화를 지향하고, zero-emission을 실현하는 첨단 발전 시스템의 종합 구현을 목표로 하고 있으며, 더불어, 도래하는 수소 경제로의 전이에 대비에 석탄을 이용한 중앙(Central) 수소생산 시스템을 구현하여 이송 및 전환을 통한 지역적 분산 이용을 가능케 하는 종합적인 인프라를 구축하는 기술이다. 본 기술에는 석탄가스화 기술, 수성가스 전환기술, 수소/$CO_2$ 분리기술, 이송용 연료 전환기술 등이 포함된다. 석탄가스화 수소생산 기술은 급등하는 오일 가격과 이의 수입사용 증가에 대응하기 위한 에너지 안보 대책 마련 및 효율 극대화의 필요성과 더불어, 전력산업에서 화력 발전시스템의 궁극적 실현 목표인 고효율, 초청정의 전력생산 시스템의 구현을 가능케 하여, 향후 화석 연료를 이용한 미래 발전 기술을 선도 할 것으로 기대된다. 더불어, 수소 경제로의 전환 시 수소 수요의 급팽창에 대비한 경제적인 대규모 수소생산 기술의 개발이 필요하며, 이에 기술 실현성이 가장 높은 석탄가스화 수소생산 기술의 개발 구현이 요구된다.

• Journal of Hydrogen and New Energy
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• v.31 no.5
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• pp.453-458
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• 2020

In this study, ethylene-propylene-diene monomer (EPDM) rubbers reinforced with various particle size of carbon black were prepared and tested. We followed recently published CSA/ANSI CHMC2 standard "the test methods for evaluating material compatibility in compressed hydrogen applications-polyemr". Measurement of change in hardness, tensile strength and volume were performed after exposure to maximum operating pressure, 87.5 MPa, for 168 hours (1 week). Once EPDM was exposed to high-pressure hydrogen, the samples experience volume increase and degradation of the physical properties. Also, after the dissolved hydrogen was fully eliminated from the specimens, the hardness and the tensile properties were not recovered. The rubber reinforced with smaller sizes of carbon black particles showed less volume expansion and decrease of physical properties. As a result, smaller particle size of carbon black filler led to more resistance to high-pressure hydrogen.

• Journal of Hydrogen and New Energy
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• v.23 no.4
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• pp.316-322
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• 2012

A fuel cell vehicle has the hydrogen detection sensors for checking the hydrogen leakage because it use hydrogen for its fuel and can't use a odorant to protect the fuel cell stack. To verify the hydrogen safety of leakage we select the high possible leak points of fittings in hydrogen storage system and test the leaking behavior at them. The hydrogen leakage flow rate is 10, 40, 118 NL/min and the criterion for maximum hydrogen leakage is based on allowing an equivalent release of combustion energy as permitted by gasoline vehicles in FMVSS301. There are total 18EA hydrogen leakage detection sensors installed in test system. we acquire the hydrogen leakage detection time and determine the ranking. Hydrogen leakage detection time decrease when hydrogen leakage flow rate increase. The minimum hydrogen leakage detection time is about 3 seconds when the flow rate is 118NL/min. In this study, we optimize hydrogen sensor position in fuel cell vehicle and verify the hydrogen leakage safety because there is no inflow inside the vehicle.

• Journal of Hydrogen and New Energy
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• v.32 no.3
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• pp.163-171
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• 2021

Securing energy sources is a key element essential to economic and industrial development in modern society, and research on renewable energy and hydrogen energy is now actively carried out. This research was conducted through experiments and analytical methods on the hydrogen filling process in the hydrogen storage tank of the hydrogen charging station. When low-temperature, high-pressure hydrogen was injected into a high-pressure tanks where hydrogen is charged, the theoretical method was used to analyze the changes in temperature and pressure inside the high-pressure tanks, the amount of hydrogen charge, and the charging time. The analysis was conducted in the initial vacuum state, called the First Cycle, and when the residual pressure was present inside the tanks, called the Second Cycle. As a result of the analysis, the highest temperature inside the tanks in the First Cycle of the high-pressure tank increased to 442.11 K, the temperature measured through the experiment was 441.77 K, the Second Cycle increased to 397.12 K, and the temperature measured through the experiment was 398 K. The results obtained through experimentation and analysis differ within ±1%. The results of this study will be useful for future hydrogen energy research and hydrogen charging station.