气–固法合成制备氢化镁及热力学分析 Preparation of MgH2 by Gas-Solid Synthesis and Thermodynamics Analysis

氢能发展日益壮大，制氢、储氢、运氢成为关键的工程技术问题。氢化镁作为镁基储氢材料，因其储氢量大，密度小，氢气释放易于控制而成为氢燃料电池领域关注的焦点之一。本文采用气–固反应法制备氢化镁，并通过对不同状态的镁(镁蒸汽与固体镁粉)与氢气的在高温高压下的合成反应进行热力学计算和实验，从而论证其大规模生产的工业可行性。热力学分析和试验验证结果表明：相比于镁在蒸汽状态下与氢气反应制备氢化镁而言，工业高纯镁固体粉末与氢气反应制备氢化镁的温度和压强条件要求较低(673 K, 7 MPa, 72 h)，可工业化制备氢化镁。 With the rapid development of hydrogen energy, hydrogen production, storage and transport be-come key issues of engineering technology. MgH2, as an Mg-based hydrogen storage material, has become the center of attention in hydrogen fuel-cell area because it has a high hydrogen capacity with less dense and easy control in hydrogen releasing. In this paper, gas-solid reaction is adopted to prepare MgH2. And a feasibility study in industry is analyzed about reactions between hydrogen with magnesium vapor and powder, respectively, by considering their thermodynamics calculation. The thermodynamics analysis and experimental results show that the temperature and pressure conditions of the reaction between hydrogen and magnesium powder are more easily fulfilled (673 K, 7 MPa, 72 h) than that between hydrogen and magnesium vapor, and that this method can be used in industry.