Research On The Technology Of High Pressure Hydrogen Storage Vessel Used In Hydrogenation Station Under Extreme Conditions

In recent years,with the adjustment of energy structure and the prominent problem of environmental pollution,clean,pollution-free and renewable hydrogen energy is expected to become the most valuable energy carrier in the 21 st century.China’s Energy Development in the New Era released by the State Council Information Office at the end of 2020 also clearly proposes to accelerate the development of hydrogen fuel cell technology industry chain and hydrogen fuel cell vehicle industry chain.Hydrogen refueling stations,as an important part of the hydrogen industry ecosystem,have also been greatly developed.As of November 2020,the number of hydrogen refueling stations has been built around the world to be 458.Due to the flammable and explosive nature of high-pressure hydrogen,high-pressure hydrogen storage vessels,as important hydrogen storage equipment in hydrogen refueling stations,will bring huge casualties and property losses in case of fire.The study on the safety performance of high-pressure hydrogen storage vessels in fire is of certain significance for the safe operation of hydrogen storage vessels in hydrogen refueling stations and construction of hydrogen refueling stations.In order to explore the laws of thermal response and pressure relief and explosion prevention of hydrogen storage vessels under fire conditions,and to provide technical support for the standardization of prevention measures of high-pressure hydrogen jet flame in hydrogenation stations in China,this paper is based on the National Key Research and Development Program Project "Research on Safety Performance Testing Technology and Equipment of Key Components in Hydrogenation"(With the support of Project No.2019YFB1505303)",the high pressure hydrogen storage cylinder vessel was taken as the research object.The CFD fluid mechanics software Fluent was used to establish a threedimensional numerical model of the combustion test and high pressure hydrogen discharge of the hydrogen storage vessel,and the combustion test process and the high pressure hydrogen discharge process after the operation of the safety valve were simulated.Combined with the existing fire test results,the release and explosion technology of high pressure hydrogen storage vessels under extreme fire conditions was studied.The research contents and main research results of this paper are as follows:(1)Combined with the specific combustion test model,a high pressure hydrogen storage vessel with a total length of 2 000 mm and a project volume of 205 L was used in the hydrogenation station to establish a physical model of combustion thermal response,and the theory of vessel wall heat transfer and medium temperature rise during the actual combustion process was studied.The mathematical model,flow field calculation boundary conditions and solution methods were determined.Combined with the experimental data,it laid a foundation for the further study of numerical simulation of hydrogen storage vessel fire.(2)By referring to the fire test of steel gas cylinder,the numerical model of fire test of 45 MPa high-pressure hydrogen storage vessel used in hydrogenation station was established,and the thermal response rule of hydrogen in the vessel and the cylinder during the fire test was obtained.The effects of different parameters,such as medium,filling pressure and ambient temperature,on the operation time of the safety valve during vessel fire were studied.The results show that the maximum pressure difference between the test results and the simulation results in the hydrogen storage vessel within 613 s is 1.1 MPa,and the relative error is3.9%.When the container is filled with air,hydrogen and nitrogen medium,the operation time of the safety valve of the hydrogen storage container is not affected by the combustion process.The safety valve can operate faster when the hydrogen storage container is tested under a higher charging pressure.When simulating under a lower charging pressure,the temperature of the hydrogen medium in the container rises faster.At this time,it is suggested that the hydrogen storage container group can adopt the combined structure of the discharge device to improve the safety performance under fire.(3)A numerical model of high-pressure hydrogen discharge was established for the safe discharge of high-pressure hydrogen storage vessels under fire,and the total discharge and flow rate of the discharge outlet were obtained by simulation calculation and compared with the calculated results of the formula.By comparing the model with the air discharge test data,the error was within an acceptable range to prove the feasibility of the model.The mole fraction diagram of hydrogen in the field was calculated during high-pressure hydrogen discharge by simulation,which was used as the safe distance during high-pressure hydrogen discharge.The simulation results can provide technical support for the design of pressure discharge of highpressure hydrogen storage vessels and the optimal setting of discharge devices under fire conditions,and provide a model reference for the subsequent high-pressure hydrogen discharge tests.