Safety analysis and quantitative risk assessment of hydrogen releases accident in a highway hydrogen refueling station

Hydrogen is a clean energy that has the advantage of a wide variety of sources. Hydrogen energy is one of the important means to replace traditional fossil energy and achieve the goal of “carbon peak and carbon neutrality”. Ensuring the safe use of hydrogen is critical for the large-scale commercialization and success of hydrogen energy initiatives. Hydrogen refueling stations are essential nodes in the development and commercialization of hydrogen energy, especially those located in highway service areas, which are characterized by high pedestrian flow and frequent traffic. Therefore, conducting a post-incident consequence analysis and quantitative risk assessment for this highway hydrogen refueling station is vital to inform their safe design and operational practices. This study uses the FLACS software to simulate potential hydrogen leakage and explosion scenarios within a hydrogen refueling station situated in a highway service area. To mitigate the potential harm from hydrogen accidents, the study assesses the protective efficacy of safety barriers against hydrogen leaks and explosions. Finally, a quantitative risk assessment is performed on the refueling station, calculating risk values for typical accident conditions and comparing these values against acceptable criteria to determine the acceptability of the risks associated with such incidents. The findings show that the strategic placement of safety barriers can significantly reduce the lateral spread of hydrogen clouds, lessening the potential harm from combustion or explosion to both humans and structures in open spaces, and consequently narrowing the required safety distances between various facilities within the station. However, due to the potential for shock wave reflection by safety barriers, leading to increased overpressure within their vicinity, it is advisable to maintain an adequate distance between these barriers and hydrogen-related equipment. For the conditions analyzed in this study, the hazard radius resulting from diffusion, fire, and explosion in the event of a hydrogen leak is relatively small, and the overall risk of such incidents is considered acceptable. The research presented in this paper offers valuable insights into the design and safety precautions of hydrogen refueling stations along highways.