N. Rajalakshmi et Ks. Dhathathreyan, Evaluation of thermodynamic parameters for hydrogen in the storage device ST-90 (R), INT J HYD E, 24(11), 1999, pp. 1067-1075
The thermodynamic parameters such as partial molar enthalpy (Delta H-H), pa
rtial molar entropy (Delta S-H), and partial molar excess entropy (Delta S-
H(E)) of the dissolved hydrogen in the hydrogen storage unit ST-90(R) conta
ining 18.6 kg of misch metal based AB(5) alloy are evaluated based on the c
alculation of Sievert's constant and from Clausius-Clapeyron equation. The
partial molar enthalpy at infinite dilution (Delta H-H(0)) and the partial
molar excess entropy at infinite dilution (Delta S-H(E.0)) have been obtain
ed from the dependence of and on the hydrogen concentration. The nature of
metal-hydrogen and hydrogen interactions are also evaluated for the three s
ingle phases namely alpha, beta and gamma. The hydrogen-hydrogen interactio
n is attractive in the alpha phase and repulsive in the beta and gamma phas
es. For the mixed phases alpha + beta and beta + gamma, it is very difficul
t to predict the nature of the interactions either as attractive or repulsi
ve. (C) 1999 International Association for Hydrogen Energy. Published by El
sevier Science Ltd. All rights reserved.