Analysis of heat transfer performance and hydrogen adsorption reaction characteristics of metal hydride reactor

A three-dimensional mathematical model for the metal hydride reactor incorporating spiral coil tube was proposed, which coupled the effects of the variation of heat transfer fluid temperature on the hydrogen adsorption rate. The present model was solved using multi-physics software and the heat transfer performance and the hydrogen adsorption reaction characteristics under various operating conditions were investigated. The results showed that hydrogen adsorption reaction could be divided into three stages. In the first stage, hydrogen pressure was a major influence. In the third stage, the reaction was mainly under the control of the heat transfer process. And the second stage was a transition phase. With the decrease of hydrogen pressure, the reaction rate and the average bed temperature reduced. When the pressure decreased to 0.6 MPa, the reaction rate reduced significantly. As the temperature of heat-transfer fluid increased, the temperature difference decreased, leading to reducing of reaction rate. When the temperature increased to 323 K, the reaction was not complete and the reaction rate reduced remarkably. In the bed, the temperature in places near spiral coil tube was low and the reaction was completely finished. However, the heat transfer performance in places far away from spiral coil tube was relatively poor and the reaction was pretty slow. Therefore, there was a direction to improve the heat transfer structure. © 2016, Editorial Department of Journal of Sichuan University (Engineering Science Edition). All right reserved.