A Study Of Metal Hydride-based Hydrogen Storage Device Using AB₅ Alloys

With the development of industrialization and globalization, the fossil energy consumption had been sped up, energy and environment problem has become a focus problem that must be solved in the world today. Hydrogen energy, as a clean energy with high-energy density, has been paid wide attentions. Hydrogen storage is one of the key issues in the hydrogen energy application. The metal hydride has become a carrier of the hydrogen storage and transportation due to the mild reaction conditions, large amount of hydrogen storage and advantages of long cycle time. Among the metal hydride materials, LaNi5 alloy has large hydrogen storage capacity, fast hydriding/dehydriding rate, low equilibrium pressure and flat pressure plateau. The purpose of this paper is to design a hydrogen storage tank with LaNi5 alloy whose storage is the same as hydrogen cylinder. By using the method of computational fluid dynamics, a physical and mathematical model of hydrogen storage has been established and verified its effectiveness. Using commercial software comsol4.4, simulation researches for hydriding/dehydriding under different operating conditions has been done, and finally simply optimized hydrogen storage reactor. The specific work includes:1. According to the amount storage of hydrogen storage bottle, the volume of metal hydride hydrogen storage tank has been confirmed, and the three types of the same volume with different draw ratio of hydrogen-storage tanks act as the object of study compared the performance of hydriding/dehydriding with different dimensions.2. Based on the real situation, the relative suitable dynamics model was chosen by studying variety of metal hydride dynamics model. The data in the literature for hydrogen storage reactor was adopted to establish the model validation.3. Hydriding performance of different size of hydrogen storage were simulated under different conditions, analyzing hydriding properties of reactor and studying the influence of draw ratio on the reactor's performance.4. Dehydriding performance of hydrogen storage tank in convective heating and electricity heating was simulated to research the change of the mass flow rate of hydrogen-storage tanks, analyzing the impact of draw ratio and back pressure.5. Two kinds of optimized structure from the aspects of heat and mass transfer were established, and the characteristics of dehydriding and the specific optimization effect simulated.