• 한국수소및신에너지학회논문집
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• 제28권2호
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• pp.166-173
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• 2017

For commercialization of hydrogen refuelling station (HRS), we need to reduce the clearance distance for jet fire in the real entities in the HRS. Thus, we revisited the current regulations of clearance distance for jet fire in the law. The law in korea has been set up by replica of japan, not by our own scientific basis. Recently, sandia lab developed Hydrogen Risk Assessment Model (HyRAM) tools and we simulated a series of circumstances such as 10 to 850 bar with several leak hole sizes. In 850 bar with 10 mm diameter hole leak cases, it shows $4,981kW/m^2$ at 12 m separation from leak source and $1,774kW/m^2$ at 17 m separation from leak source. In 850 bar with 1 mm diameter leak hole, it shows $0.102kW/m^2$ at 12 m separation and $0.044kW/m^2$ at 17 m separation. Current law may be acceptable with 1 mm hole size with 850 bar.

• Nuclear Engineering and Technology
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• 제51권8호
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• pp.1939-1950
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• 2019

The MELCOR code useful for a plant-specific hydrogen risk analysis has inevitable limitations in prediction of a turbulent flow of a hydrogen mixture. To investigate the accuracy of the hydrogen risk analysis by the MELCOR code, results for the turbulent gas behavior at pipe rupture accident were compared with CFX results which were verified by the American National Standard Institute (ANSI) model. The postulated accident scenario was selected to be surge line failure induced by station blackout of an Optimized Power Reactor 1000 MWe (OPR1000). When the surge line failure occurred, the flow out of the surgeline was strongly turbulent, from which the MELCOR code predicted that a substantial amount of hydrogen could be released. Nevertheless, the results indicated nonflammable mixtures owing to the high steam concentration released before the failure. On the other hand, the CFX code solving the three-dimensional fluid dynamics by incorporating the turbulence closure model predicted that the flammable area continuously existed at the jet interface even in the rising hydrogen mixtures. In conclusion, this study confirmed that the MELCOR code, which has limitations in turbulence analysis, could underestimate the existence of local combustible gas at pipe rupture accident. This clear comparison between two codes can contribute to establishing a guideline for computational hydrogen risk analysis.

• 한국수소및신에너지학회논문집
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• 제30권6호
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• pp.499-504
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• 2019

Due to the rapid spread and low minimum ignition energy of hydrogen, rupture is highly likely to cause fire, explosion and major accidents. The self-ignition of high-pressure hydrogen is highly likely to ignite immediately when it leaks from an open space, resulting in jet fire. Results of the diffusion and leakage simulation show that jet effect occurs from the leakage source to a certain distance. And at the end of location, the vapor cloud explosion can be occurred due to the formation of hydrogen vapor clouds by built-up. In the result, it is important that depending on the time of ignition, a jet fire or a vapor cloud explosion may occur. Therefore, it is necessary to take into account jet effect by location of leakage source and establish a damage minimizing plan for the possible jet fire or vapor cloud explosion. And it is required to any kind of measurements such as an interlock system to prevent hydrogen leakage or minimize the amount of leakage when detecting leakage of gas.

• 한국수소및신에너지학회논문집
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• 제30권4호
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• pp.338-346
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• 2019

During last years, hydrogen refueling infrastructure test and devices research for hydrogen station presented a significant growth consisting of the commercialization of fuel cell electric vehicles (FCEVs). However, we still have many challenges for making commercial hydrogen stations such as increased safety and cost reduction. This study demonstrates the low cost hydrogen storage tank (type 2) and effective winding method for high pressure hydrogen storage. We use numerical analysis to verify stress changes inside the wire according to the winding condition. Also liner size, winding wire size and wire tension were studied for the safety and cost down. Results show that the stress of winding wire decreased with increased winding angle and increased the liner diameter. On the other hand, the stress of winding wire increased according to the increased wire thickness and tension.

• Elastomers and Composites
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• 제55권4호
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• pp.270-276
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• 2020

The long-term durability of an FKM O-ring used as parts of a hydrogen station was investigated by exposing it to high-pressure gaseous hydrogen for 1, 3, and 7 days at room temperature. Changes in its sealing force were subsequently measured at 150℃ using intermittent compression stress relaxation (CSR). No changes in the tensile properties of FKM O-ring were observed, but its initial and overall sealing forces at 150℃ significantly decreased with increasing exposure time to hydrogen gas. Microvoid formation in the FKM O-ring upon exposure to high-pressure hydrogen was minimized over time after the ring was exposed to atmospheric pressure at room temperature, which prevented changes in its tensile properties. However, applying heat accelerated FKM O-ring oxidation, which decreased its sealing force. These results indicated that identifying changes in the sealing force of rubber materials using intermittent CSR is not sufficient for monitoring changes in mechanical properties under high-pressure hydrogen atmospheres; however, it is suitable for evaluating the long-term durability of sealing materials for hydrogen station applications under similar conditions.

• 한국수소및신에너지학회논문집
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• 제32권3호
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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.

• 한국가스학회지
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• 제21권5호
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• pp.56-63
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• 2017

전세계적으로 수소 충전 스테이션 구축에 많은 투자와 지원을 하고 있는 실정이다. 그러나 수소는 폭발범위가 넓고 확산이 빠른 기체이다. 본 연구에서는 액화수소를 취급하는 소규모~대규모 충전스테이션을 대상으로, 사고시 발생하는 VCE로 인한 피해영향범위를 산출하고, 프로빗 모델을 통해 주변의 인적, 물적 피해를 예측하였다. 더불어, 벤트스택 끝단에서 발생 가능한 Jet fire를 시나리오로 선정하여 최적 높이를 설정하였다. 피해영향범위는 관심과압 6.9kPa을 기준으로 하여, 소규모 저장시설의 경우 8.24m, 중규모 14.10m, 대규모 22.38m이다. 폐출혈로 인한 인체 피해는 소규모와 중규모가 각각 50m, 대규모 100m였으며, 구조물 손상에 따른 피해는 소규모 200m, 중규모 300m 및 대규모 500m이다. 벤트스택의 최적높이는 소규모 4.7m, 중규모 8.8m 및 대규모 16.9m이다.

• 한국가스학회지
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• 제24권1호
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• pp.41-48
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• 2020

본 연구는 기존의 CNG충전소에 복합으로 수소충전소를 건설하는 형태의 수소-CNG 복합충전소에 대한 정량적 위험성평가를 수행하였다. 수소충전소와 CNG충전소에서 발생할 수 있는 사고시나리오를 도출하고 각 시나리오에 대한 사고발생빈도를 고려하여 개인적, 사회적 위험도를 계산하였다. 위험성평가 결과 사회적 위험도는 허용가능 범위에 들어 왔으나, 개인적 위험도에 있어서는 일부 지역에서 허용범위를 벗어나는 구간이 발생하였고, 위험성기여도 분석을 통해 고위험요소를 발굴하였다. 수소-CNG 복합충전소에서는 CNG 저장용기, 압축기, 제어 판넬에서 대규모 누출이 발생할 경우 높은 위험도를 보이게 되며 충전소 전체 위험도의 약 88%를 기여하게 된다. 따라서 이러한 고 위험요소에 대하여는 주기적이고 집중적인 안전관리가 이루어져야 한다.

• 한국연소학회:학술대회논문집
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• 한국연소학회 2014년도 제49회 KOSCO SYMPOSIUM 초록집
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• pp.113-113
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• 2014

This study has been conducted for evaluation of qualitative/quantitative risk of HCNG filling station. In case of fire explosion occurred because of hydrogen, CNG, and HCNG leaking on same conditions, maximum overpressure was measured as 30kPa for hydrogen, 3.5kPa for HCNG, and 0.4kPa for CNG. The overpressure of HCNG was measured 7.75 times higher than that of CNG, but it was only 11.7% compared with hydrogen. When the explosion was occurred, in case of hydrogen, the measured influential distance of overpressure was 59m and radiant heat was 75m. In case of CNG, influential distance of overpressure was 89m and radiant heat was 144m would be estimated. In case of 30% HCNG that was blended with hydrogen and CNG, influential distance of overpressure was 81m and radiant heat was 130m were measured. As the explosion occurred with the same sized container that had 350bar for hydrogen and 250bar of CNG and HCNG, the damage distance that explosive overpressure and radiant heat influenced CNG was seen as the highest. HCNG that was placed between CNG and hydrogen tended to be seen as more similar with CNG.

• 한국가스학회지
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• 제25권4호
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• pp.43-48
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• 2021

본 연구는 가스사고 전문해석 프로그램인 FLACS를 이용하여 진행하였다. 안전성해석 대상인 수소충전소는 압축설비, 저장탱크, 수소 배관 등으로 구성되어있다. 주요 시설 및 구성품의 설계 사양, 수소충전소 주변의 환경 조건 등을 반영한 후 잠재적 위험요인에 대한 안전성해석을 실시하였다. 국내 수소충전소는 2021년 기준 약 70여곳의 충전소가 보급되어있으며, 향후 2040년에는 1200기 도입이 예정되어있다. 수소충전소의 안전한 보급을 위해 잠재적 위험에 의한 발생 가능한 사고를 대비하고자 누출·확산 시나리오를 도출하여 안전성을 검토하고자 한다.