Computational study on metal hydride based three-stage hydrogen compressor

A mathematical model for predicting the performances of a three-stage metal hydride based hydrogen compressor (MHHC) is presented. The performance of the MHHC is predicted by solving the unsteady heat and mass transfer characteristics of the coupled metal hydride beds of cylindrical configuration. The governing equations for energy, momentum and mass conservations, and reaction kinetic equations are solved simultaneously using the finite volume method. Metal hydrides chosen for a three-stage MHHC are LaNi5, MmNi4.6Al0.4 and Ti0.99Zr0.01V0.43Fe0.99Cr0.05Mn1.5. Numerical results obtained for a single-stage MHHC using MmNi4.6Al0.4 are in good agreement with the experimental data reported in the literature. Using three-stage compression, a maximum pressure ratio of 28 is achieved for the supply conditions of 20 °C absorption temperature and 2.5 bar supply pressure. A maximum delivery pressure of 100 bar is obtained for the operating conditions of 20 °C absorption temperature and 120 °C desorption temperature.

► We developed a mathematical model of three-stage metal hydride based hydrogen compressor.
► Numerical results are validated with experimental data.
► The effects of operating parameters on the performance of the system are presented.
► Optimum operating parameters of the system are predicted.