Heat and mass transfer in a concentric-annular-tube bed packed with ZrV_1.9Fe_0.1 particles

Pressure-composition isotherms of the ZrV_1.9Fe _0.1-hydrogen system were determined by a constant volume method and were correlated to an empirical van't Hoff equation. The enthalpy change of hydrogen absorption was correlated to a function of the hydrogen-to-alloy atomic molar ratio. The entropy change was independent of it. Heat and mass transfer process in a concentric-annular-tube bed packed with the ZrV _1.9Fe_0.1 particles was studied experimentally and numerically as a basic study of hydrogen storage at elevated temperature. A one-dimensional concentric-annular-tube bed was charged with hydrogen. The experimental profiles of hydrogen partial pressure and temperature were compared with numerical simulation calculated by the pressure-composition isotherm, a hydrogenating rate equation and two balance equations of hydrogen and heat. Another simplified analysis using three dimensionless lump parameters succeeded in estimating temperature profiles in the hydrogen-absorbing-alloy bed more easily. The simulation was able to make it better to understand contributions of experimental parameters such as the flow rate, surrounding temperature and other physical properties.