(347e) Hydrogen Release Characterization and Simulation for Safe Design of Hydrogen Fueling Station

Hydrogen
is a prominent fuel for a renewable and environment-friendly energy carrier. It
can simultaneously reduce a country's reliance on foreign oil and considerably
reduce greenhouse gases. Significant advances have been made in the use of
hydrogen as a transportation fuel and a fuel for power generation. Hydrogen can
be used in an internal combustion engine or a fuel cell to generate power. A
number of hydrogen fueling stations are under construction to fuel
hydrogen-driven vehicles. It would be essential to ensure the safety of
hydrogen station equipment and operating procedure in order to prevent any leak
and explosions of hydrogen: safe design of facilities at hydrogen fueling
stations e.g. pressurized hydrogen leak from storage tanks. Several researches
have centered on the behaviors of hydrogen ejecting out of a set of holes of
pressurized storage tanks or pipes. Y. Lee et al. [1] have developed an
effective operator training program providing the safety information and the
public relations for the safer usage of hydrogen at hydrogen fueling stations. Some
studies related to the safety of hydrogen stations have been concerned with the
diffusion of leakage, explosion, deflagration or detonation of hydrogen and jet
flames from hydrogen fueling stations [2].

This
work focuses on the experiment and 3D simulation of hydrogen leak scenario
cases at a hydrogen fueling station, given conditions of a set of pressures,
100, 200, 300, 400 bar and a set of hydrogen ejecting hole sizes, 0.5, 0.7, 1.0
mm. The physical points for probing hydrogen concentrations along with the
centerline of leak jet stream are positioned at a set of horizontal distances
away from the hydrogen cylinder; 1, 3, 5, 7 and 9 m. Hydrogen concentrations
are measured from 5 samplers and collected from 5 probe points. In this work,
the simulation is performed using FLACS because one of the primary aims of this
study is to identify safe distances in case of hydrogen explosion and FLACS, a
CFD tool designed to simulate behaviors of both leak and explosion, is used to
calculate the concentration profile of high pressure hydrogen in released jet
stream. The simulation results are validated with experimental data and
compared with those of previous study [3]. The simulation is based on real 3D
geometrical configuration of a hydrogen fueling station that is being
commercially operated in Korea. The simulation results are validated with
hydrogen jet experimental data to examine the diffusion behavior of leak
hydrogen jet stream.

The
safety distance is defined as a distance between a major facility and building
where people reside. Each nation has its own standard for the safety distances.
It is defined as a distance at which the allowable burst pressure of 0.1226 bar
is considered on the premise that it will not cause any human damage to the
surroundings of the business or any property loss except minor ones. To
identify the safety distances in hydrogen fueling stations, explosion
scenario-based dynamic simulation is made, given a layout of facilities comprising
the station. Hydrogen blast pressure profiles are calculated in case of
explosion using FLACS, which provides information on the distribution
characteristics of blast pressure through geometric facility configurations,
and the directionality and development of explosion. 3D Simulation results of
scenarios are shown in Fig. 1. Finally, a set of marginal safe configurations
of fueling facility system are presented, together with an analysis of
distribution characteristics of blast pressure, directionality of explosion. This
work makes an important contribution to an enactment of official hydrogen
safety distance in Korea being in the absence of such a standard as well as
marginal hydrogen safety design for hydrogen fueling stations, enabling to keep
a reasonable balance between less construction cost and high safety.

Fig. 1. 3D Simulation
results of scenarios

REFERENCES

[1] Lee YH, Kim
JK, Kim JH, Kim EJ, Kim YG, Moon I. Development of a web-based 3D virtual
reality program for hydrogen station. Int J Hydrogen Energy 2010;35:2012-8.

[2] Zheng J, Bie
H, Xu P, Liu P, Zhao Y, Chen H, Zhao L. Numerical simulation of high-pressure
hydrogen jet flames during bonfire test. Int J Hydrogen Energy 2012;37:783-90.

[3] Kim EJ, Lee
KW, Kim JS, Lee YH, Park JD, Moon I. Development of Korean hydrogen fueling
station codes through risk analysis. Int J Hydrogen Energy 2011;36:13122-31.