Development of a metal hydride hydrogen compressor with high-pressure hydrogen storage alloys

Abstract

Single- and double-stage metal hydride hydrogen compressors (MHHC) were developed using two series of metal hydrides of AB5-based La0.5Ce0.5Ni5-xAlx (x = 0, 0.1, 0.2) alloys and AB2-based Ti1-yZryMn0.8Cr1.2 (y = 0.05, 0.1, 0.2) alloys. In single-stage mode, La0.5Ce0.5Ni5 and Ti0.9Zr0.1Mn0.8Cr1.2 alloys could produce hydrogen pressures of 117 atm and 132 atm, respectively, at 100 °C. When the temperature was raised to 140 °C, both alloys could produce hydrogen pressures of 200 atm. The Ti0.9Zr0.1Mn0.8Cr1.2 alloy exhibited higher hydrogen discharging pressure and faster kinetics than those of the La0.5Ce0.5Ni5 alloy. A pair of alloys were used for a double-stage MHHC (first stage: Ti0.9Zr0.1Mn0.8Cr1.2; second stage: Ti0.95Zr0.05Mn0.8Cr1.2). The initial hydrogen pressure of 50 atm increased to 245 atm when the working temperature was raised from 25 °C to 100 °C, which provides an opportunity for designing a compact and simple MHHC.