• Journal of the Korean Institute of Gas
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• v.16 no.1
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• pp.15-21
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• 2012

An analysis was completed of the hazards distance of hydrogen accidents such as jet release, jet fire, and vapor cloud explosion(VCE) of hydrogen gas, and simplified equations have been proposed to predict the hazard distances to set up safety distance by the gas dispersion, fire, and explosion following hydrogen gas release. For a small release rate of hydrogen gas, such as from a pine-hole, the hazard distance from jet dispersion is longer than that from jet fire. The hazard distance is directly proportional to the pressure raised to a half power and to the diameter of hole and up to several tens meters. For a large release rate, such as from full bore rupture of a pipeline or a large hole of storage vessel, the hazard distance from a large jet fire is longer than that from unconfined vapor cloud explosion. The hazard distance from the fire may be up to several hundred meters. Hydrogen filling station in urban area is difficult to compliance with the safety distance criterion, if the accident scenario of large hydrogen gas release is basis for setting up the safety distance, which is minimum separation distance between the station and building. Therefore, the accident of large hydrogen gas release must be prevented by using safety devices and the safety distance may be set based on the small release rate of hydrogen gas. But if there are any possibility of large release, populated building, such as school, hospital etc, should be separated several hundred meters.

• Transactions of the Korean hydrogen and new energy society
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• v.25 no.2
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• pp.161-172
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• 2014

Hydrogen, which can be produced from abundant and widely distributed renewable energy resources, seems to be a promising candidate for solving the concerns for improving energy security, urban air pollution, and reducing greenhouse gas emissions. The two primary motivating factors for hydrogen economy are fossil fuel supply limitations and concerns about global warming. But the safety issues associated with hydrogen economy need to be investigated and fully understood before being considered as a future energy source. Limited operating experience with hydrogen energy systems in consumer environments is recognised as a significant barrier to the implementation of hydrogen economy. To prevent unnecessary restrictions on emerging codes, standards and local regulations, safety policies based on real hazards should be developed. This article studies briefly the direct impact-distances from hazard events such as hydrogen release and jet fire, and damage levels from hydrogen gas explosion in a confined space. Based on the direct impact-distances indicated in the accident scenarios and consumer environments in Korea, the safety policies, which are related to hydrogen filling station, hydrogen fuel cell car, portable fuel cell, domestic fuel cells, and hydrogen town, are suggested to implement hydrogen economy. To apply the safety policies and overcome the disadvantages of prescriptive risk management, which is setting guidance in great detail to management well known risk but is not covering unidentified risk, hybrid risk management model is also proposed.

• 한국연소학회:학술대회논문집
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• 2012.04a
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• pp.245-246
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• 2012

The possibility that self-ignition can be generated near an obstacle is high in practical applications such as a hydrogen car. In this paper, experimental investigations were suggested to understand the effects of a wall on self-ignition phenomena through high-speed images. The results showed that the existence of a wall could not change the ignition phenomena itself irrespective of wall height and burst pressure. However, when a strong flame was induced in the tube, a wall could promote the flame stabilization.

• Transactions of the Korean hydrogen and new energy society
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• v.28 no.2
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• pp.225-230
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• 2017

Coal oil is widely used as a home heating fuel for portable and installed coal oil heaters. Today, Coal oil is widely used as fuel for jet engines and some rocket engines in several grades. This paper describes the performance characteristics according to the compression ratio of spark ignition engine fuelled with coal oil. As a result, the following knowledge is obtained: As the compression ratio is decreased, there is an increase in torque, indicated mean effective pressure (IMEP), heat release rate, and brake thermal efficiency. Higher compression ratio of the engine decreases the ignition delay period, combustion period, and cooling loss.

• Journal of Korean Tunnelling and Underground Space Association
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• v.23 no.6
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• pp.535-547
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• 2021

A policy to expand the hydrogen economy has been established in Korea and the supply of FCEV is being expanded to realize a hydrogen society. Therefore, the supply of FCEV is expected to increase rapidly, and a solution to respond to accidents of FCEV is required. In this study, an experimental study was conducted to analyze the effect of the hydrogen jet flame generated by a FCEV on the inner wall of the tunnel and the characteristics of the internal radiant heat. For the experiment, the initial pressure of hydrogen tank was set to 700 bar, and the injection nozzle diameter was set to 1.8 mm in order to make the same as the conditions generated in the FCEV. In addition, a tunnel fire resistance test specimen having the same strength as the compressive strength of concrete applied to general tunnels of 40 MPa was manufactured and used in the experiment. The results were analyzed for the separation distance (2 m and 4 m) between the hydrogen release nozzle and the tunnel fire resistance test concrete. As the result, the maximum internal temperature of the test concrete was measured to 1,349.9℃ (2 m separation distance), and the radiant heat around the jet flame was up to 39.16 kW/m².

• Journal of Korean Tunnelling and Underground Space Association
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• v.23 no.1
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• pp.47-60
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• 2021

Hydrogen is a next-generation energy source, and according to the roadmap for activating the hydrogen economy, it is expected that industries to stably produce, store, and transport of hydrogen as well as the supply of hydrogen fuel cell vehicles will be made rapidly. Accordingly, safety measures for accidents of hydrogen vehicles in confined spaces such as tunnels are required. In this study, as part of a study to ensure the safety of hydrogen fuel cell vehicles in road tunnels, a basic investigation and research on the risk of fire and explosion due to gas leakage and hydrogen tank rupture among various hazards caused by hydrogen fuel cell vehicle accidents in tunnels was conducted. The following results were obtained. In the event of hydrogen fuel cell vehicle accidents, the gas release rate depends on the orifice diameter of TPRD, and when the gas is ignited, the maximum heat release rate reaches 3.22~51.36 MW (orifice diameter: 1~4 mm) depending on the orifice diameter but the duration times are short. Therefore, it was analyzed that there was little increase in risk due to fire. As the overpressure of the gas explosion was calculated by the equivalent TNT method, in the case of yield of VCE of 0.2 is applied, the safety threshold distance is analyzed to be about 35 m, and number of the equivalent fatalities are conservatively predicted to reach tens of people.