TY - JOUR

T1 - Effects of exit-pressure variation on the hydrogen supply characteristics of metal hydride reactors

AU - Yang, Tian Shiang

AU - Tsai, Meng Lung

AU - Ju, Din Sun

N1 - Funding Information:
The authors gratefully acknowledge the Taiwan National Science Council for supporting this work through grant No. NSC98-2221-E-006-170-MY2 . They would also like to thank Professors C.-J. Ho and C.-D. Wen of NCKU, and Dr. B.-H. Chen of ITRI, for a number of fruitful discussions on this work and other related topics.

PY - 2010/8

Y1 - 2010/8

N2 - 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 LaNi5 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" (tPD, during which the exit-pressure is decreasing) and the initial exit-pressure drop rate (ṗe0) are the control parameters. Results of a systematic parameter study indicate that, for a given t PD, increasing ṗe0 generally increases the mean hydrogen discharge rate, while there is a particular ṗe0 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.

AB - 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 LaNi5 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" (tPD, during which the exit-pressure is decreasing) and the initial exit-pressure drop rate (ṗe0) are the control parameters. Results of a systematic parameter study indicate that, for a given t PD, increasing ṗe0 generally increases the mean hydrogen discharge rate, while there is a particular ṗe0 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.

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U2 - 10.1016/j.ijhydene.2010.04.175

DO - 10.1016/j.ijhydene.2010.04.175

M3 - Article

AN - SCOPUS:77955571721

SN - 0360-3199

VL - 35

SP - 8597

EP - 8608

JO - International Journal of Hydrogen Energy

JF - International Journal of Hydrogen Energy

IS - 16

ER -