稀土-镁-镍系储氢合金的合成与吸放氢动力学研究

项目名称： 稀土-镁-镍系储氢合金的合成与吸放氢动力学研究

项目编号： No.51464008

项目类型： 地区科学基金项目

立项/批准年度： 2015

项目学科： 矿业工程

项目作者： 刘静

作者单位： 贵州师范大学

项目金额： 49万元

中文摘要： 氢的储存是氢能利用的关键。稀土-镁-镍系AB3及A2B7型储氢合金室温下吸放氢性能优异，成本相对低廉，有很好的应用前景。吸放氢反应动力学的研究是选择最佳工艺参数、对反应器进行设计的重要前提。本项目拟采用中间合金粉末作为原料，利用粉末烧结或燃烧合成技术制备上述合金并测试其性能。同时建立一套针对吸放氢反应各步骤作为控速环节的等温及非等温宏观动力学模型。将该模型体系应用在稀土-镁-镍系储氢合金中，了解等温及非等温条件下反应温度、氢气压力、升温速率及颗粒度等参数对合金吸放氢控速环节、速率、转化率及起始吸放氢温度的影响。最后，根据模型方程预报吸放氢反应的最佳反应条件和对应的反应动力学曲线。本项目的特色是理论模型中考虑了反应体系热力学性质对动力学过程的影响，同时针对反应过程中合金结构、反应条件的暂态性对模型进行修正。另外，模型方程中各参数均有明确的物理意义，可推广到其他类似的气固反应领域。

中文关键词： 储氢材料；稀土合金；吸放氢反应；动力学模型；粉末烧结

英文摘要： Hydrogen storage is the key point to the use of hydrogen energy. RE-Mg-Ni-based AB3 and A2B7 alloys are considered to be the promising materials for hydrogen storage due to their excellent performance in hydrogen absorption and desorption at room temperature and relatively low cost. Gas-solid kinetics is an important standard for selecting the best process parameters of hydrogen absorption/desorption and designing the reactor of hydrogen storage materials. In our subjet, the master alloys will be used as raw materials and the hydriding combustion synthesis or sinter synthesis will be used to prepared the RE-Mg-Ni alloys. At the same time, we suggest to establish a set of new models to describe the hydrogen absorption and desorption macro-kinetics processes which controlled by chemical adsorption, surface penetration, internal diffusion, chemical reaction, nucleation and growth under isothermal and non-isothermal conditions. These models will be applied in RE-Mg-Ni alloys to evaluate the influences of temperature, pressure of hydrogen, heating rate and particle size on the controlling step, rate, conversion rates and initial hydrogen desorption temperature of hydrogen absorption and desorption process under the isothermal and non-isothermal conditions. Finally, the optimum reaction condition and reaction time of hydrogen absorption should be calculated and forecasted based on the new model. This project is characterized by these theoretical models which considering the influence of thermodynamic properties on dynamic process of the reaction system. Moreover, the change of alloy structure during reaction and the transient performance of reaction conditions will also be considered to the modified models. In addition, all parameters in models should have clear physical meanings and these model equations can be popularized and applied to other similar gas-solid reactions fields.

英文关键词： Hydrogen storage material;RE-Alloy;Hydrogen Absorption-Desorption;Kinetics model;powder metallurgy