车用天然气储罐脱附放气过程热力特性

Thermodynamic Properties Analysis of Natural Gas Vehicle Tank in Desorption

车用吸附天然气储罐在脱附放气过程中产生的热效应,严重影响了储罐的脱附效率和汽车行驶速度.建立了天然气、活性炭吸附剂和天然气储罐的热质交换模型,模拟计算了脱附过程中储罐内温度、压力和脱附量的变化,分析了温度、压力等热力参数对脱附速度和脱附量的影响.计算结果表明:储罐的自然脱附过程是吸热过程,在脱附过程中,储罐内的平均温度由293.15K降到了250.46K;储罐中心处温降最大,由293.15K降至244K,降幅达到了49.15K;自然对流下的脱附效率比等温脱附降低了24.49%;在自然对流条件下,壁面所提供的热量越少,脱附速度越小,脱附效率也就越低.

Thermal effect produced in desorption of natural gas vehicle tank seriously affects desorption efficiency and vehicle velocity.The variation of storage tank temperature,pressure and desorption amount are simulated and the influence of storage tank temperature and pressure on the desorption rate and the desorption amount are analyzed based on the newly-erected heat and mass transfer model of natural gas,activated carbon adsorbents and gas tank.The results show that desorption process is an endothermic process;the average temperature of adsorbent in the storage tank reduces from 293.15 K to 250.46 K and the maximum temperature at the center of the storage tank reduces from 293.15 K to 244 K with a margin of 49.15 K.At the same time,the desorption rate in natural convection is lower than that of the isotherm desorption by 24.49%.Under natural convection,the desorption rate and efficiency varies with the heat of the wall.