Leakage-type-based analysis of accidents involving hydrogen fueling stations in Japan and USA

Flame characteristics of premixed H2-air mixtures explosion venting in a spherical container through a duct

In order for fuel cell vehicles to develop a widespread role in society, it is essential that hydrogen refueling stations become established. For this to happen, there is a need to demonstrate the safety of the refueling stations. The work described in this paper was carried out to provide experimental information on hydrogen outflow, dispersion and explosion behaviour. In the first phase, homogeneous hydrogen-air-mixtures of a known concentration were introduced into an explosion chamber and the resulting flame speed and overpressures were measured. Hydrogen concentration was the dominant factor influencing the flame speed and overpressure. Secondly, high-pressure hydrogen releases were initiated in a storage room to study the accumulation of hydrogen. For a steady release with a constant driving pressure, the hydrogen concentration varied as the inlet airflow changed, depending on the ventilation area of the room, the external wind conditions and also the buoyancy induced flows generated by the accumulating hydrogen. Having obtained this basic data, the realistic dispersion and explosion experiments were executed at full-scale in the hydrogen station model. High-pressure hydrogen was released from 0.8-8.0mm nozzle at the dispenser position and inside the storage room in the full-scale model of the refueling station. Also the hydrogen releases were ignited to study the overpressures that can be generated by such releases. The results showed that overpressures that were generated following releases at the dispenser location had a clear correlation with the time of ignition, distance from ignition point. INTRODUCTION In order for the ‘hydrogen economy’ to become a reality, not only is their a requirement to develop the fuel cell technology and associated equipment and infrastructure in an economic manner, but also it is necessary to demonstrate that all aspects of the supply and use of hydrogen can be performed safely. Osaka Gas Co., Ltd. has been operating a hydrogen refuelling station [1] safely as a demonstration plant, in parallel with developing a compact hydrogen reformer [2], (see Figure 1). However, in 2003, Osaka Gas joined the Japanese National Project on Hydrogen, with the aim of carrying out further work to investigate the safety aspects of hydrogen refuelling stations. One of the particular aims of this work was to help establish a suitable ‘safety zone’ around such a station. Figure 1: Osaka Gas’s hydrogen station (left) and hydrogen production unit, HYSERVE (right)

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Experimental study on hydrogen explosions in a full-scale hydrogen filling station model

Chemical kinetic behaviors at the chain initiation stage of CH4/H2/air mixture

A numerical study of hydrogen leakage and diffusion in a hydrogen refueling station

Safety studies on high-pressure hydrogen vehicle refuelling stations: Releases into a simulated high-pressure dispensing area

Experimental study of hydrogen explosion in repeated pipe congestion – Part 2: Effects of increase in hydrogen concentration in hydrogen-methane-air mixture

M. Royle

Papers

Safety studies on high-pressure hydrogen vehicle refuelling stations: Releases into a simulated high-pressure dispensing area

Experimental study of hydrogen explosion in repeated pipe congestion – Part 2: Effects of increase in hydrogen concentration in hydrogen-methane-air mixture

Experimental study of hydrogen explosion in repeated pipe congestion – Part 1: Effects of increase in congestion