DYNAMIC CHARACTERISTICS OF THE HYDROGEN SORPTION PROCESS IN MMNI4.15FE0.85HX COMPACTS

It is shown that the dynamic pressure P//d//y//n prevailing upon the process of hydrogen sorption by metal hydrides differs considerably from the equilibrium pressure P//e//q at the same temperature. However, for a dynamic process (nonzero hydrogen flow), isothermal conditions must be preserved in order to define a temperature of the hydride bed. It was shown that it was possible to achieve this to an accuracy of plus or minus 0. 5 degree C, with limited hydrogen flow rates, for compacted hydrides having a high thermal conductivity. Dynamic P//d//y//n-T-C characteristics upon desorption were determined for PMH compacts of MmNi//4//. //1//5Fe//0//. //8//5H//x with an 18 wt. % aluminum matrix. Constant hydrogen flow-rate experiments were interpreted by means of a gas dynamics model for compressible fluids and corresponding rate equations were given.