Study and characterization of a metal hydride container

Sorption performance tests were conducted on a small metal hydride hydrogen-storage prototype container. The relevant aspects considered are mainly the activation behavior, desorption capacity, desorption flow rates and heat transfer. The alloy employed to fill the container is of the AB5AB5 intermetallic type, its chemical composition is MmNi4.7Al0.3MmNi4.7Al0.3 (Mm stands for “mischmetal,” a mixture of rare earths) and its equilibrium pressure at room temperature is about 300 kPa, which is adequate for the required operating conditions.Pressure evolution was monitored during discharge tests at constant temperature for different flow rates and initial charge pressures. A decrease in the dynamic pressure measured during the discharge was observed as a function of time, in agreement with the alloy plateau pressure slope. Also, a decrease in the dynamic discharge pressure with increasing discharge flow rates was found, associated with the hydride decomposition kinetics and heat transfer conditions.