Experimental Study On Temperature Field Of Hydrogen Absorption Process In Metal Hydride Reactor

With the rapid development of the global economy,the consumption of fossil energy has caused energy depletion and serious ecological pollution,while hydrogen energy has the characteristics of green,clean,abundant and recyclable,which attracts the attention of countries all over the world.Among them,metal hydride hydrogen storage technology has obvious advantages and has become a hot spot after high-pressure hydrogen storage.In this paper,in view of the hydrogen storage alloy in the process of hydrogen absorption will send a lot of calories,results in uneven bed reactor,reactor under different operating conditions is studied temperature change trend,analyze the temperature variation characteristics,and to the improvement of the structure of the reactor,the heat exchange structure after the reactor temperature field distribution,which provide certain reference significance for its practical application.In the experiment of hydrogen storage performance of LaNi₅ and LaY₂Ni_9.7Mn_0.5Al_0.3alloys,activation properties and hydrogen absorption/dehydrogenation curves at different temperatures were obtained through PCT and activation tests.The experimental results show that the two alloys have the same activation conditions and can be fully activated only 2-3times.The fully activated alloys have good kinetic properties.The amount of hydrogen absorption/dehydrogenation of LaY₂Ni_9.7Mn_0.5Al_0.3.3 alloy is greater than that of LaNi₅ alloy at different temperatures.The hydrogen absorption/dehydrogenation platforms of the two alloys are of low pressure at 25?,and have great hysteresis at room temperature.With the increase of temperature,the amount of absorption/dehydrogenation of LaNi₅ and LaY₂Ni_9.7Mn_0.5Al_0.3alloy increases continuously,the pressure of the absorption/dehydrogenation platform increases continuously,and the hysteresis factor decreases continuously.The reaction enthalpy of LaNi₅ alloy obtained from the Van't Hoff curve was greater than that of LaY₂Ni_9.7Mn_0.5Al_0.3.3 alloy.In the experiment of reactor temperature field,the distribution of reactor temperature field under different conditions,including inlet pressure,inlet flow rate and the improvement of reactor internal structure,was analyzed by comparing the temperature change curve.The experimental results show that when hydrogen is charged at a constant intake pressure and full flow rate,the temperature inside the reactor rises rapidly and the temperature rise of the upper and lower bed is uneven.When the intake pressure rises continuously,the maximum temperature between the inner and outer wall of the reactor is higher,and the hydrogenation reaction time is shorter.When hydrogen is charged at a constant intake rate,the temperature rise of the whole reactor is more stable,and the time for the bed to reach the maximum temperature is longer.However,the maximum temperature of the bed is lower than that of the full-flow hydrogen supply mode.The maximum reactor bed temperature of LaY₂Ni_9.7Mn_0.5Al_0.3.3 alloy was lower than that of LaNi₅ reactor.The air inlet pipe can obviously improve the uneven temperature rise of the reaction bed,improve the hydrogen absorption performance of the alloy at the bottom of the reactor,and speed up the hydrogen absorption reaction rate of the alloy.Heat transfer fins can improve the heat transfer performance of the reactor,reduce the maximum temperature reached by the bed,and timely conduct excess heat in the reactor to the outer wall.