The fast refueling of compressed hydrogen has an important influence on the efficiency and safety of the filling process. Precision measurements of the thermodynamic characteristics of hydrogen under the filling process are becoming more important as hydrogen energy is developed and used. One of the key elements of hydrogen fuel cell vehicles is the on-board hydrogen storage cylinder (HSC). Due to the compression of the hydrogen during filling, there could be a fast increase in temperature. The tank's maximum temperature and maximum fueling pressure are both restricted to less than 358.15 K and 125% of the tank's design pressure for safety reasons. This study revealed the hydrogen temperature rise during refueling and developed a theoretical model for computing the temperature rise in the HSC during the high-pressure refueling procedure. The HSC filling procedure was examined using a theoretical approach. Also, the relationship between the refueling procedure and the temperature change of hydrogen in the type IV tank was investigated. The temperature evolution mechanism of various HSCs was explained, and predictions were made for the minimum precooling temperature needed for hydrogen under various filling scenarios. The results of the theoretical analysis gave a theoretical foundation to the present method for controlling the hydrogen temperature of the gas source in the hydrogenation station, which then enables us to determine the optimum amount of energy needed for cooling hydrogen in the hydrogen refueling station.

With the development of the petrochemical industry, the number of storage tanks has continuously increased, exacerbating the issue of oil evaporation losses. Therefore, it is urgent to find efficient and economical measures to reduce oil evaporation losses. This paper establishes a diffusion model for internal floating roof tanks (IFRTs) and uses numerical simulation methods to study the mass fraction distribution, pressure distribution, and the variation patterns of oil vapor inside the tanks at different floating roof heights. The results show that the closer to the top of the tank, the lower the oil vapor mass fraction, and the mass fraction distribution is almost symmetrical. As the floating roof height decreases, the vapor mass fraction in the mixed gas region inside the tank gradually decreases, showing a distribution below the lower explosive limit (LEL), indicating improved safety. Furthermore, the study found that in the benchmark model, the behavior characteristics of gasoline vapor are reflected in the changes in mass fraction, velocity, and pressure distribution, where the oil vapor concentration in the upper part is lower but evenly distributed. By comparing the behavior characteristics of oil vapor inside the tank at different floating roof heights, it was found that the floating roof height significantly affects the diffusion and accumulation of oil vapor. The presence of vents effectively reduces the accumulation of oil vapor concentration, improving the stability and safety inside the tank. For different floating roof height scenarios (such as CASE 1, CASE 2, and CASE 4), the oil vapor behavior characteristics are similar. The study results provide important theoretical support for the future development of oil vapor recovery technologies and the design of enclosed energy-saving recovery devices inside tanks, indicating that optimizing the floating roof height and vent system design can significantly reduce oil evaporation losses.