An experimental study and heat transfer analysis of porous adsorption reactors

• Main Authors: Chien-MingWu, 吳健銘
• Other Authors: Tian-Shiang Yang
• Format: Others
• Language: zh-TW
• Published: 2013
• Online Access: http://ndltd.ncl.edu.tw/handle/86817752546036719977

碩士 === 國立成功大學 === 機械工程學系碩博士班 === 101 === The hydriding process in a hydrogen storage system involves a reversible exothermic chemical reaction. The heat released during the reaction process has a direct effect on the hydrogen supply characteristics and therefore must be carefully managed. However, in investigating and enhancing the performance of hydrogen systems, experimental cost and safety are major concerns. Therefore, metal hydride powder is substituted by silica gel in our experimental study of the thermal management of porous adsorption reactors. The temperature variation with time within reactors in both hydrogen system and silica system are similar. Thus, relatively safe silica gel system is a proper material to mimic the thermal behavior of hydrogen storage system. In the present study, air with a known humidity and flow rate flows into a reactor filled with silica gel and the temperature, pressure, flow rate and humidity are measured both within the reactor and at the reactor outlet as the exothermal chemical reaction proceeds. The heat transfer characteristics at a point in the reactor are explained by physical arguments, and then a simplified mathematic model is constructed to support the physical arguments. Temperature at three axial positions in silica system are shown and the heat diffusion equation is employed to interpret the temperature variation in axial positions. The temperature variation, adsorption heat power, adsorption mass and humidity of outlet air under different conditions are shown and interpreted on physical grounds. The obtained results show that the moisture adsorption rate and adsorption heat power increase as the average reactor pressure and inlet humidity increase. Since the heat transfer characteristics in silica gel system and hydrogen system are similar, by improving the heat transfer in a silica system, the heat transfer problem in a hydrogen system can also be solved indirectly.