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ISSN Online: 2377-424X

ISBN Print: 978-1-56700-421-2

International Heat Transfer Conference 15
August, 10-15, 2014, Kyoto, Japan

Investigation of Heat and Mass Transfer in a Magnesium Hydride Heat Storage Reactor

Get access (open in a dialog) DOI: 10.1615/IHTC15.tst.008881
pages 9079-9091

Abstract

Based on the promising magnesium/magnesium hydride heat storage system, a three-dimensional mathematical model and the relative experimental apparatus were established to study the heat and mass transfer phenomena during the exothermic process. The numerical results show that the heat transfer capability of the system is the most critical factor which affects the reaction rate. By adding a cooling coil, the heat transfer capability of the system has a great improvement and the corresponding reaction rate is promoted. Moreover, the choice of wall temperature also significantly affects the speed of the reaction rate. The experimental results show that while the hydrogen pressure is kept constant, there exists an optimum wall temperature for the system to achieve the fastest reaction rate. When the hydrogen pressure is maintained at 30 atm, the relative optimum wall temperature is 340°C. Besides, the optimum wall temperature will change with the changing hydrogen pressure, as the optimum value will decrease from 340°C to 300°C while the hydrogen pressure increases to 35 atm. When the wall temperature is constant, the reaction rate will raise with the increasing hydrogen pressure. The results also show that the particle size of the reactants has an important influence on the reaction rate and reaction extent. When the particle size of magnesium powder decreases from 100 mesh to 400 mesh, the reaction extent increases from 24% to 56%, and the corresponding reaction rate also has a significant promotion.