Effects of exit-pressure variation on the hydrogen supply characteristics of metal hydride reactors

✍ Scribed by Tian-Shiang Yang; Meng-Lung Tsai; Din-Sun Ju

• Publisher: Elsevier Science
• Year: 2010
• Tongue: English
• Weight: 499 KB
• Volume: 35
• Category: Article
• ISSN: 0360-3199
• DOI: 10.1016/j.ijhydene.2010.04.175

✦ Synopsis

Here we examine how the temporal mean and steadiness of the hydrogen discharge rate of a metal hydride reactor (MHR) vary, when its exit-pressure is deceased quadratically with time. To accomplish this task, a mathematical model accounting for the hydrogen desorption kinetics of LaNi 5 and the mass and energy balance in a cylindrical MHR is solved numerically. The initial and final exit-pressures of the MHR are prescribed, whereas the "pressure-drop time" (t PD , during which the exit-pressure is decreasing) and the initial exitpressure drop rate ð _ p e0 Þ are the control parameters. Results of a systematic parameter study indicate that, for a given t PD , increasing _ p e0 generally increases the mean hydrogen discharge rate, while there is a particular _ p e0 that minimizes the variance of the hydrogen discharge rate. The MHR exit-pressure variation therefore can be "optimized" to discharge hydrogen with maximized temporal steadiness. Some other strategies for MHR performance improvement also are discussed here.