基于Aspen Plus的甲烷三重整热力学模拟

摘要

To optimize reaction conditions and improve the efficiency of catalyst , the reaction process is analyzed on methane tri-reforming by thermodynamic , the relationship between the equilibrium constant and the temperature is calculated ,also the competition abilities of the reactions in the reforming process are compared .The influences of reaction temperature and pressure on the reforming characteristics are studied as well .The CH4 and CO2 conversion ratio ,H2/CO ratio and reactor heat duty of 1 331 different feed ratios are calculated by using Aspen Plus analysis .The results show that the conversion rate increases with temperature and decreases with pressure ,so the optimum reaction temperature and pressure are 1 123 .15 K and 101 .325 kPa respectively . Under this condition ,with the mole ratio of CH4 :CO2 : H2 O:O2 being 1:0 .2:0 .1:0 .5 in the feed gases , the reforming system can realize self-heating avoiding carbon deposition on catalyst .At this time , CH4 and CO2 conversion rate reach 99 .35% and 46 .98% respectively ,the product gas with a H2/CO ratio of 1 .73 .%为了优化反应条件及提高催化剂的反应效率 ,从热力学角度对甲烷三重整的反应过程进行了分析,求出了平衡常数与温度的关系式 ,据此对重整过程中各反应的竞争能力进行了比较.研究了反应温度、压力对重整结果的影响.利用Aspen Plus软件采用排列组合的方法 ,求出了1331种不同进料比下CH4 、CO2 转化率、n(H2 )/n(CO)、积碳量及反应器热负荷的值 ,并进行了筛选.结果表明 ,升温有利于CH4 和CO2 的转化 ,但压力升高不利于反应的正向进行 ,从而确定了最佳反应温度和压力分别为1123 .15K和101 .325 kPa.在此条件下 ,当 n(CH4 ): n(CO2 ): n(H2O ): n(O2 )为1:0 .2:0 .1:0 .5时,积碳量为零且系统能够实现自热.此时,CH4 和CO2 的转化率分别为99 .35% 和46 . 98% ,n(H2 )/n(CO )=1 .73.