Towards high-efficiency of hydrogen purification in metal hydride

Abstract

Recent advancement on hydrogen (H2) retrieval in a mixture gas of H2/CO2 based on the metal hydride (MH) technique has attracted numerous interests. In this work, we implement the lumped element model simulation to conduct a theoretical approach on the hydrogen purification process. The influence of orifice geometry and temperature of the tank, and inflow gas rate (fin) is investigated. The results show that the discharge coefficient (DC) is affected by the tank's orifice geometry. The orifice shape is increasing the value of DC, as a result, the CO2 (impurity) outflow rate heightens during the venting process and thereby promoting to obtain a high hydrogen purity. By overcoming the exothermic/endothermic effect in the absorption/desorption step and a proper fin selection, we find an improvement in the hydrogen storage capacity (wt%) into MH and consequently the hydrogen recovery rate increases. A sharp improvement in orifice geometry and thermal conditions of the tank, and fin enhances the main targeted results (hydrogen purity and recovery rate) and ensures the proper operation of the MH technique.