Scheme of thermal compression of hydrogen (TCH) using MmNi4.25Al0.75 recovered with ethyl alcohol and handled under non protective atmospheres

S. OBREGÓN; M.R. ESQUIVEL

INTERNATIONAL JOURNAL OF HYDROGEN ENERGY

PERGAMON-ELSEVIER SCIENCE LTD

Lugar: Amsterdam; Año: 2014 vol. 39 p. 8577 - 8581

0360-3199

A MmNi4.25Al0.75 intermetallic was obtained by low energy mechanical alloying and low temperature heating at 600 _C for 24 h under Ar. The intermetallic was recovered from milling chamber using ethyl alcohol, dried, stored and handled under air at room conditions. Structure was characterized by XRD. A maximum stability temperature of 160 _C was obtained from non-isothermal DSC measurement under air. The kinetics of oxidation at 200 _C was analyzed. A maximum reaction degree (a ¼ 0.1) was obtained after 2500 s of treatment. The hydrogen sorption properties of samples were studied by volumetric measurements. Hydrogen maximum mass percent capacity (mass %) was reached in less than 300 s. The thermodynamic sorption properties were measured. Values of DHf ¼ _29 _ 2 kJ mol_1 and DSf ¼ 197 _ 10 J mol_1 K_1 were obtained for absorption process and DHd ¼ 28 _ 2 kJ mol_1 and DSd ¼ 189 þ 10 J mol_1 K_1 were obtained for desorption process. From these results, a one-stage of thermal compression of hydrogen is proposed with a standard compression ratio (Rc) of 5.71 in the 25e80 _C range.