Research On Hea Tstrorage Performance And Device Based On Reversible Hydrogen Reaction Process Of Mg-Based Ma Terial

The hydrogenated Mg-3Ni-2MnO₂ is fabricated by planetary type ball millingunder hydrogen atmosphere;Through analysis method of XRD, SEM, the grain size andmicrostructure are analyzed and measured;The heat storage kinetics properties and thebasic discipline of the temperature field evolution under the condition of practicalreaction bed is tested by home-made pilot plant;The intrinsic thermal storage kineticsequation is established using theory of nucleation and growth, to reveal the couplingmechanism of hydrogen absorption and heat release;And a preliminary heat storageexperimental exploration is carried out in the big capacity heat storage apparatus.The results show that: In this paper the heat storage capacity of Mg-3Ni-2MnO₂composite material is up to 2600 kJ/Kg. In the heat storage process, the higher the initialtemperature is, the time required to complete heat storage is shorter; The larger thequality of thermal energy storage material is, the time required to complete fully heatstorage is longer; In the heat storage process,the reaction bed temperature of 1g thermalenergy storage material is not decreased with the release of hydrogen because of itsfaster heat transfer speed, while the reaction bed temperature of 10g thermal energystorage material is just to show on the contrary . In the exothermic process, the initialtemperature, inlet pressure and the quality of the reaction bed have an influence onexothermic and temperature performance , the lower the initial temperature, the greaterthe inlet pressure and the less the reaction bed mass is, the time required for thecompletion of heat release is shorter. The mass of 1g thermal energy storage materialreaction bed has a rapid reaction period, the heat released by hydrogen will help tocomplete reaction quickly, while the mass of 10g thermal energy storage material,subjected to the impact of heat and mass transfer, its heat release performance showsdifferent from the mass of 1g thermal energy storage material reaction bed.According to numerical simulation results,during the process of Mg-3Ni-2MnO₂ hydrogen absorption , there is a critical temperature, in the below of critical temperature,the higher the temperature is, the more favorable the rate of heat release is; Above thecritical temperature, the higher the temperature is, the slower the rate of heat releaseis;During the heat release process , three temperature zones are divided according to thekinetics character. For zone A, the higher the temperature is, the more excellent thekinetics property is. For zone B, the higher the temperature is, the weaker the kineticsproperty is, despite the fact that the heat release process can be finished in relativelyshort time. For zone C, the heat can not be released. It is concluded that the temperatureof the mass of 1g thermal energy storage material is raised because of the heatreleased by the hydrogen reaction which is beneficial to complete the reaction. The heatrelease dynamics performance of the mass of 10g reaction bed is poor due to the impactof heat and mass transfer. For this thermal energy storage material ,the reaction bed heatand mass transfer optimization is the key to achieve engineering applications.The exploratory experimental study of the big capacity heat storage apparatusshows that:the thermal energy storage material developed in this paper has an excellentthermal storage capacity, has ability to achieve electrical energy storage in the form ofchemical energy, and release the heat in time of necessary occasions.