压力和温度对用于燃料电池的微型反应器内甲烷自热重整特性的影响

Influences of Pressure and Temperature on Characteristics of Auto-thermal Reforming of Methane in Microreactors Used for Fuel Cells

采用CHEMKIN化学反应动力学软件及计算流体力学软件CFD等数值方法详细探讨了在微尺度内甲烷自热重整反应中温度和压力对出口组分摩尔分数的影响和催化壁面总积碳量的影响.结果表明,当温度超过873 K,会促进水煤气转化反应的发生,导致氢气减少、水和一氧化碳增加,用于燃料电池的微型反应器内甲烷自热重整的温度不宜超过1000K,此时重整合成气中氢气的摩尔分数可达54.05%,一氧化碳的摩尔分数为9.98%;从能效、积炭和燃料电池的原料气的要求分析,用于燃料电池的微型反应器内甲烷自热重整的反应压力应低于1.8105Pa;同时在1000K左右,积炭过程和消炭过程可到达一个平衡阶段,有利于催化剂寿命的延长。

Chemical reaction kinetics model and computational fluid dynamics software were used to study the mole fraction of components in outlet and the total carbon deposition in catalytic wall with the influence of temperature and pressure on micro-scale auto-thermal reforming reaction of methane. The results show that if the temperature is higher than 873 K, it will promote the occurrence of water gas shift reaction and lead to decrease of hydrogen and increase of water and carbon monoxide. The temperature of auto-thermal reforming reaction of methane in micro-reactor used in fuel cell should not be higher than 1 000 K. On this condition, the mole fraction of hydrogen in reforming syngas can reach 54.05% and the mole fraction of carbon monoxide is 9.98%. Based on energy efficiency, carbon deposition and the requirements of feed gas of fuel cell, it indicates that the pressure of auto-thermal reforming reaction of methane in micro-reactor used in fuel cell should be lower than 1.8×10^5 Pa. At the same time when the temperature is about 1 000 K, carbon deposition process and carbon elimination process can reach an equilibrium state, which is benefit to prolong catalyst life.