Consequence analysis of CNG leakage at joint refueling and charging stations

The number of new-energy vehicles is steadily increasing worldwide, and joint refueling and charging stations will be increasingly constructed and developed in China. A CNG leakage at joint stations can lead to superimposed consequences, including fire (flash fire, pool fire, jet fire), explosion, and release of toxic and hazardous gases. Based on FLACS and SAFETI, the impact of leakage aperture and wind direction on CNG leakage diffusion are analyzed by modeling a joint refueling and charging station in Shaanxi, China. The safe distance between charging piles and leakage points is investigated in the worst case scenario. The superimposed consequences of leakage in joint stations under different scenarios are analyzed, and the individual risk is analyzed at stations. This study shows that the larger the leakage aperture, the larger the CNG leakage dispersion range under the same wind directions and wind speeds, and the higher the wind speed, the more volatile the gas under the same leakage apertures. The safety distance of the charging pile should reach at least 37 and 40 m considering leaks in the tanker and gas storage well, respectively. The impact range of superimposed consequences shows the descending order of jet fire > flash fire > pool fire.