甲烷二氧化碳重整热力学分析

Thermodynamic analysis of methane reforming with carbon dioxide

关键词:  平衡常数  重整  Aspen Plus  热力学  自热 

Key words:  equilibrium constant  reforming  Aspen Plus  thermodynamics  auto-thermal

摘要:

为了优化反应条件及提高催化剂的反应效率,采用平衡常数法对甲烷二氧化碳重整制合成气进行了热力学分析,计算出该反应发生的最低可行温度为914 K。研究了反应温度、压力及反应原料进气组成对重整特性的影响。结果 表明,温度在1 123 K和常压下,CH₄和CO₂的转化率可分别达到94.47%和97.31%,且温度升高有利于转化率的提高, 而压力升高却不利于反应正向进行。随着原料气中n(CH₄)/n(CO₂)比值的增加,CH₄和CO₂转化率呈现单调但相反的变化趋势,当n(CH₄)/n(CO₂)=1.2时,CO₂的转化率可达99.29%,n(H₂)/n(CO)为0.99。O₂含量增加,使CH₄和CO₂转化率分别升高和降低,且使n(H₂)/n(CO)的值增加; 当n(CH₄)∶ n(CO₂)∶n(O₂)=1.2∶1∶0.575时,能使反应实现自热。 

Abstract:

To optimize reaction conditions and improve the reaction efficiency of catalyst, an equilibrium constant method was applied to study the thermodynamic influences of operating parameters, such as reaction temperature, pressure and feed inlet composition, on the reforming properties. The minimum feasibility temperature of the reaction was calculated to be 914 K. The results showed that the methane conversion increased with temperature and decreased with pressure. At 1 123 K,the conversions of CH₄ and CO₂ achieved 94.47％and 97.31％ respectively. When the molar ratio of CH₄ and CO₂ increased, the conversion of CH₄ and CO₂ appeared a drab but opposite change tendency, when molar ratio of CH₄ and CO₂ is 1.2, CO₂ conversion rate reached 99.29% and molar ratio of H₂ and CO was 0.99. By the introduction of oxygen, the conversion of CH₄ increased, but that of CO₂ reduced, and the molar ratio of H₂ and CO increased. When the molar ratio of CH₄, CO₂ and O₂ was 1.2∶1∶0.575, auto-thermal reaction could be realized.