Medium-scale metal hydride hydrogen storage container: modelling and experimental studies

Abstract

The article presents results of development of the medium scale (up to 1.4 Nm³ H₂) externally heated/cooled prototype metal hydride container intended for the use in a hydrogen storage tank on-board fuel cell forklift. The container uses powdered composite of C14-Laves-type hydride-forming intermetallic (A=Ti+Zr; B=Mn+V+Cr+Ni+Fe) additionally doped with Cu and La for the improvement of activation performance, with the additive of reduced graphite oxide for absorption of stresses caused by the lattice expansion of the parent intermetallic upon hydrogenation, as well as for the augmentation of heat transfer performance of the metal hydride bed. Further improvement of the heat transfer was achieved by the use of transversal copper fins inside the cylindrical container. The design of the metal hydride container was optimised towards maximising the size of a single unit while preserving fast hydrogen charge/discharge dynamics using 3D CFD modelling. The modelling results were validated by the experimental tests of the container’s hydrogen charge and discharge characteristics. It was shown that about 70% of the full hydrogen storage capacity is achieved during 10–15 minutes-long charge with hydrogen at the pressure of 50 bar and ambient temperature; about 90% of the capacity of the fully charged container can be released at the flow rate of 10 NL/min and output pressure above 4 bar when heating the container to 40°C. H₂ delivery at the specified flow rate and pressure can be maintained during 20–30 minutes even at the ambient temperature.