Numerical analysis of candidate materials for multi-stage metal hydride hydrogen compression processes

A numerical study on multistage metal hydride hydrogen compression (MHHC) systems is presented and analyzed. Multistage MHHC systems use a combination of different materials to increase the final compression ratio at the end of the compression process. In the current work a numerical model is proposed to describe the operation of a complete three-stage MHHC cycle, which can be divided in seven steps (for a three-stage compression system): first stage hydrogenation process, sensible heating of first stage, coupling process between the first and the second stage, sensible heating of the second stage, second coupling with the upcoming sensible heating of the third stage material and finally the delivery of high pressure hydrogen to a high pressure hydrogen tank. Three scenarios concerning the combination of different materials for the compression stages are introduced and analyzed in terms of maximum compression ratio, cycle time and energy consumption. According to the results, the combination of LaNi5 (stage 1), MmNi4.6Al0.4 (stage 2) and a novel synthesized AB2-Laves phase intermetallic (stage 3) present a compression ratio 22:1 while operating between 20- 130 oC.

Publisher Statement: NOTICE: this is the author’s version of a work that was accepted for publication in Renewable Energy. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Renewable Energy, [111, (2017)] DOI: 10.1016/j.renene.2017.04.037

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