| The porous material adsorption hydrogen storage technology has the advantages of high hydrogen storage density,rapid charging and discharging,and high safety.It is a promising hydrogen storage method.This paper uses numerical simulation method to simulate the low-temperature adsorption of hydrogen storage tank to study its charging/discharging characteristics.First,simulating the hydrogen charging and discharging of small hydrogen storage tanks with different adsorption materials to study the hydrogen charging and discharging properties.Then,modifying the geometric structure of the hydrogen storage tank to improve the problem of heat accumulation caused by adsorption heat and compression work during the adsorption process.The vehicle-mounted hydrogen storage tank with heat exchange fins is used for adsorption hydrogen storage simulation,the working conditions and the size of the hydrogen storage tank during the adsorption simulation process of the vehicle-mounted hydrogen storage tank are changed,and the pressure,temperature and other characteristics of the simulation results are compared and analyzed.The specific research content and results are as follows:First,the hydrogen storage tank and the hydrogen storage adsorption material are described,and the research on the hydrogen charging/discharging of the hydrogen storage tank is introduced.The adsorption material mainly introduces the metal organic framework material and activated carbon with the best adsorption effect at present.Then,describing the relevant theories of the simulation in this paper,and introducing the basic theories,including the mass conservation equation,momentum conservation equation,and energy conservation equation,as well as the mass source and heat source term equations in the COMSOL Multiphysics language.The adsorption behavior of adsorbent materials can be better described by introducing theoretically related formulas such as adsorption and the gas state equation.Then,the finite element software COMSOL Multiphysics is used to realize the hydrogen charging/discharging simulation.Useing COMSOL Multiphysics software to perform low-temperature adsorption simulations on small hydrogen storage tanks equipped with different adsorption materials MOF-177 and AX-21-33,and compareing and analyzeing their charging/discharging characteristics（pressure,temperature,mass balance,etc.）.The results show that MOF-177 has better hydrogen storage performance.Next,the problem of high temperature accumulation in the hydrogen storage tank due to the heat of adsorption and compression work during the adsorption process is addressed.The geometric model is optimized,that is,heat exchange fins are added at the bottom and at the bottom of the hydrogen storage tank,and the hydrogen storage tanks with heat exchange fins at different intervals are simulated for adsorption.By comparing the results of pressure and temperature distribution,the results show that the addition of heat exchange fins can effectively reduce the temperature level in the hydrogen storage tank and solve the problem of high temperature accumulation at the bottom.Finally,a vehicle-mounted hydrogen storage tank equipped with heat exchange fins is selected as the geometric model to simulate two different adsorption materials,MOF-177 and AX-21-33,for low-temperature adsorption hydrogen storage.Then choosing MOF-177 with better adsorption performance as the adsorption material,changing the operating conditions of the vehicle-mounted hydrogen storage and the size of the hydrogen storage tank,and analyzing and comparing the adsorption characteristics of different simulation results.The results show that a higher inflation rate can greatly save inflation time and cost.Increasing thermal conductivity and initial pressure can greatly improve the adsorption effect.Low temperature adsorption has irreplaceable advantages over room temperature adsorption,and the adsorption quality increases with the increase of the size of the hydrogen storage tank. |
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