Development and optimization of a two-stage metal hydride hydrogen compressor with AB2-type alloys

Abstract

This study reports the development of a two-stage metal hydride hydrogen compressor (MHHC) capable of compressing hydrogen from 1 to 30 MPa through a temperature change between 20 and 150 °C. AB2-type hydrogen storage alloys in the C14 Laves phase are employed, where A = Ti and Zr and B = Cr, Mn, and V. The pressure transfer conditions between the two stages are investigated, and the composition of the AB2 alloys is optimized accordingly: the Mn content x in Ti0.8Zr0.2Cr1.9？xMnxV0.1 and the Zr content y in Ti1？yZryCr1.2Mn0.8, for the 1st and the 2nd stage materials, respectively. A laboratory-scale two-stage compressor is fabricated and operated using the selected alloys, whereby hydrogen is successfully compressed to 30 MPa. The compression capacity is analyzed to estimate the useable capacity of the materials. The results of this study can serve as a guide for the design and evaluation of multistage MHHCs.