Dynamic modeling and simulation of hydrogen supply capacity from a metal hydride tank

• Published in: International journal of hydrogen energy Vol. 38; no. 21; pp. 8813 - 8828
• Main Authors: Cho, Ju-Hyeong, Yu, Sang-Seok, Kim, Man-Young, Kang, Sang-Gyu, Lee, Young-Duk, Ahn, Kook-Young, Ji, Hyun-Jin
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 17.07.2013; Elsevier
• Subjects: Alternative fuels. Production and utilization; Applied sciences; Circulation; Discharge; Dynamic modeling; Energy; Exact sciences and technology; Fuel cell system; Fuels; Hydrogen; Hydrogen storage; Hydrogen supply; Mathematical models; Metal hydride; Metal hydrides; Tanks; Water tanks; Water temperature; Fuel cell system; Hydrogen supply; Metal hydride; Dynamic modeling; Hydrogen; Hydrides; Modeling; Fuel cell
• ISSN: 0360-3199; 1879-3487
• DOI: 10.1016/j.ijhydene.2013.02.142

The current study presents a modeling of a LaNi5 metal hydride-based hydrogen storage tank to simulate and control the dynamic processes of hydrogen discharge from a metal hydride tank in various operating conditions. The metal hydride takes a partial volume in the tank and, therefore, hydrogen discharge through the exit of the tank was driven by two factors; one factor is compressibility of pressurized gaseous hydrogen in the tank, i.e. the pressure difference between the interior and the exit of the tank makes hydrogen released. The other factor is desorption of hydrogen from the metal hydride, which is subsequently released through the tank exit. The duration of a supposed full load supply is evaluated, which depends on the initial tank pressure, the circulation water temperature, and the metal hydride volume fraction in the tank. In the high pressure regime, the duration of full load supply is increased with increasing circulation water temperature while, in the low pressure regime where the initial amount of hydrogen absorbed in the metal hydride varies sensitively with the metal hydride temperature, the duration of full load supply is increased and then decreased with increasing circulation water temperature. PID control logic was implemented in the hydrogen supply system to simulate a representative scenario of hydrogen consumption demand for a fuel cell system. The demanded hydrogen consumption rate was controlled adequately by manipulating the discharge valve of the tank at a circulation water temperature not less than a certain limit, which is increased with an increase in the tank exit pressure. •Dynamic process of hydrogen discharge from a metal hydride tank is simulated.•Hydrogen discharge is initially driven by pressurized gaseous hydrogen in the tank.•Hydrogen discharge is then driven by hydrogen desorption from the metal hydride.•Hydrogen consumption demand scenario is simulated using PID control logic.•Circulation water temperature plays a significant role in fulfilling hydrogen demand load.