• Journal of the Korean Institute of Gas
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• v.27 no.4
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• pp.116-122
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• 2023

In addition to analyzing the hydrogen economy trends of the international community (Korea, the United States, Europe, Japan, etc.), which is being promoted to realize a carbon-neutral society, this study compared and analyzed the differences between the gaseous hydrogen refueling station, which is a key hydrogen-using facility close to the people, and a liquefied hydrogen refueling station that is scheduled to be built in the future. In addition, SAFETI, a quantitative risk assessment program, was used to analyze the safety of liquefied hydrogen refueling stations and In consideration of the individual and societal risks and the ranking of risks by facility, which are conditional allowable areas, a plan to improve safety such as facility layout was proposed

• Transactions of the Korean hydrogen and new energy society
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• v.33 no.1
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• pp.55-60
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• 2022

As interest in sustainable and eco-friendly energy sources is increasing due to various problems in the carbon society, a hydrogen economy using hydrogen as a main energy source is emerging. While the natural gas reforming method generates carbon dioxide, the water electrolysis method based on renewable energy is eco-friendly. The water electrolysis device currently being developed uses a 2 Nm³/hr class alkaline aqueous solution as an electrolyte and produces hydrogen based on renewable energy. In this study, risk assessment was conducted for these water electrolysis devices

• Proceedings of the KSME Conference
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• 2007.05b
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• pp.2026-2031
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• 2007

Hydrogen is receiving much research attention as an alternative substitute for hydrocarbon fuels these days due to its cleanliness and renewability. However, hydrogen should be used with caution because of its high propensity for leak and wide flammable range. This study deals with a situation that hydrogen leaks and then forms a flammable mixture inside 1kW class residential fuel cell. The residential fuel cell was modeled as a box-shaped chamber with vent openings at the top and bottom, filled with various components such as reformer, desulfurizer, fuel cell stack and humidifier. Computational fluid dynamics (CFD) was used to simulate the diffusion, buoyant flow and accumulation of leaked hydrogen in the modeled chamber. From the simulation, the risk region vulnerable to flame was identified and the methods to minimize such hazardous region was discussed. When the vent openings are 1% of the total surface, as the quantity of hydrogen leakage increases the risk regions increases accordingly. As the vent openings of the total surface increased from 1% to 2.3%, averaged hydrogen mole fraction is under 1% in the system.

• Transactions of the Korean hydrogen and new energy society
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• v.33 no.1
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• pp.61-66
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• 2022

In order to introduce the hydrogen economy and increase supply, research in the field of hydrogen production is being actively conducted. Among the hydrogen production methods, the method of steam reforming from natural gas and producing it currently accounts for about 50% of the global hydrogen production. In the method of steam reforming process, hydrogen can be produced by adding a reformer to an existing natural gas supply pipe. Because of these advantages, it is evaluated as a realistic production method at present in Korea, where the city gas supply chain is well established. But there is concern in that it is highly likely to be installed in downtown areas and residential spaces. In this study, the risk of the process of steam reforming to produce hydrogen was reviewed.

• Transactions of the Korean hydrogen and new energy society
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• v.25 no.6
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• pp.609-619
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• 2014

In the present study, the frequency of the undesired accident was estimated for a quantitative risk assessment of a large-scale hydrogen liquefaction plant. As a representative example, the hydrogen liquefaction plant located in Ingolstadt, Germany was chosen. From the analysis of the liquefaction process and operating conditions, it was found that a $LH_2$ storage tank was one of the most dangerous facilities. Based on the accident scenarios, frequencies of possible accidents were quantitatively evaluated by using both fault tree analysis and event tree analysis. The overall expected frequency of the loss containment of hydrogen from the $LH_2$ storage tank was $6.83{\times}10^{-1}$times/yr (once per 1.5 years). It showed that only 0.1% of the hydrogen release from the $LH_2$ storage tank occurred instantaneously. Also, the incident outcome frequencies were calculated by multiplying the expected frequencies with the conditional probabilities resulting from the event tree diagram for hydrogen release. The results showed that most of the incident outcomes were dominated by fire, which was 71.8% of the entire accident outcome. The rest of the accident (about 27.7%) might have no effect to the population.

• Journal of Energy Engineering
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• v.28 no.3
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• pp.10-17
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• 2019

According to South Korea's policy of supplying eco-friendly hydrogen vehicles, related industries are actively conducting research on the development of hydrogen cars and hydrogen charging station infrastructure. On the other hand, there is a lack of empirical research and assessment of the risk of non-metallic materials (such as liners, seals, gaskets) for classified materials that directly affect the durability and reliability of hydrogen vehicles and hydrogen charging stations. In this study, the risk factors for liners and seals of non-metallic parts used in high-pressure hydrogen installations were derived using FMEA, and the RPN values were calculated by converting the severity, frequency of occurrence and degree of detection into scores. The maximum value of the RPN 600, minimum value 63, average value 278.5 was calculated and periodic control of the liner and seal was identified as important. In addition, through hydrogen soakage and oxygen aging tests for non-metallic rubber products, physical test values that can be used as basic data were presented.

• Korean Chemical Engineering Research
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• v.60 no.3
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• pp.356-362
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• 2022

Research related to hydrogen technology is being actively conducted around the world. Korea is also making great efforts to develop technology to leap forward as a hydrogen economy powerhouse. In particular, the world's No. 1 hydrogen vehicle penetration rate is proof of this. However, the construction of hydrogen refueling stations is being delayed. The biggest delay factor is the public opposition. As such, policies without public support cannot be successfully implemented and are not sustainable. Therefore, this study intends to analyze the factors affecting the acceptability of hydrogen refueling stations in favor of and against them. As a research method, the basic factors affecting acceptability were identified by reviewing previous studies, and a questionnaire was designed and investigated based on the established factors. The validity and reliability of the questionnaire were verified, and the hypothesis was verified through correlation analysis. And, using structural equation modeling, a factor model was developed on the acceptability of hydrogen refueling stations. As a result of the study, acceptability defined private acceptability and public acceptability. In the case of private acceptability, it was confirmed that the higher the attitude toward the environment, the higher the level of knowledge about the hydrogen charging station, and the lower the degree of feeling the risk of the hydrogen charging station, the higher the acceptability. In the case of public acceptability, it was confirmed that the higher the benefit, the better the attitude toward the environment, and the lower the risk-taking characteristics of the individual, the higher the acceptability. Therefore, in this study, based on the potential factors verified in previous studies, the main factors affecting the acceptance on hydrogen refueling stations were identified. And the acceptance model was developed using structural equation modeling. This study is expected to provide basic data to seek ways to improve the acceptance of public when implementing national policies such as hydrogen refueling stations, and to be used analysis data for scientific communication.

• Transactions of the Korean hydrogen and new energy society
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• v.33 no.6
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• pp.660-673
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• 2022

In achieving carbon neutrality and the hydrogen economy, the estimation of H₂ cost is critical in terms of CCU technologies. This study analyzes LCOH of hydrogen produced by the carbon utilization unit with methane reforming and CO₂ from thermal power plant. LCOH for H₂ made with CO is estimated in three ways of Joint Cost Allocations with financial performance risk assessment. Regarding cost analysis, the zero value of LCOH is $6,003/ton. We found that the CCU technology has economic feasibility in terms of profitability. The sensitivity analysis result shows that the input ratio is more influential to the LCOH than other variables. Risk analysis presents the baseline price of zero value of LCOH - $8,408/ton, which is higher than the cost analysis - $6,003/ton. Mainly, the price variability of natural gas primarily affects the LCOH. The study has significant value in analyzing the financial performance risks as well as the cost of H₂ produced by a Plasma-based CCU system.

• Journal of the Korean Institute of Gas
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• v.27 no.4
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• pp.110-115
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• 2023

According to the Off-Gas Generation and Use Status Report (2015), Off-gas from the steel industry is estimated to be 80 million tons per year in Korea. If this is purified, large amounts of hydrogen can be produced, so active research and development related to hydrogen purification facilities is underway. In this study, a quantitative risk assessment (QRA) was conducted by analyzing the components of a off-gas based hydrogen purification facility and investigating risk factors. The risk analysis results were determined to be at an acceptable level and will be used as basic data to improve the safety of facilities considering the risks of hydrogen.

• Transactions of the Korean hydrogen and new energy society
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• v.28 no.2
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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.