费托合成油品加氢裂化异构化反应的热力学

摘要

利用 Benson 基团贡献法和 ABWY 法计算了费托合成油品的标准摩尔生成焓、标准熵及摩尔定压热容等基础数据，在298-750 K，对费托合成油品加氢裂化异构化反应体系的反应焓、吉布斯自由能以及平衡常数等热力学数据进行了计算；对体系中各反应的热力学可能性与生成顺序进行了判断以及各反应的热力平衡与限度进行了分析。结果表明：费托合成油品加氢裂化异构化反应是放热反应，低温时大部分反应在热力学上均能够自发的进行，且平衡常数均较大，能够进行到较高的程度；从热力学上看，升高温度不利于加氢裂化异构化反应的进行，适宜反应温度的选择应兼顾各种反应的进行；烯烃比烷烃更容易发生加氢裂化异构化反应；所获得的热力学数据可为费托合成油品加氢裂化异构化工艺研究、反应器开发以及新型催化剂研制等提供理论依据。%The standard molar enthalpy of formation,the standard entropy and isobaric molar heat capacity of Fischer-Tropsch syncrude were estimated by Benson group contribution method and ABWY method.The enthalpy change,Gibbs free energy change and equilibrium constant of hydrocracking and isomerization reaction of Fischer-Tropsch syncrude were calculated as a function of the temperature from 298 K to 750 K.The thermodynamic possibility and formation sequences of hydrocracking and isomerization reaction of Fischer-Tropsch syncrude were judged.Meanwhile,the thermodynamic equilibrium and the limit of different reaction steps were also analyzed. The results show that the hydrocracking and isomerization reaction of Fischer-Tropsch syncrude is an exothermic reaction,most of which are spontaneous at low temperature and can reach to a deep extent.Improving the temperature is not good for hydrocracking and isomerization reaction from a thermodynamic point of view.The choice of the suitable temperature should take into account all the reactions.The occurrence of the hydrocracking and isomerization reaction of alkene is easier than that of alkane.The thermodynamic data obtained can provide the theoretical basis for the study of hydrocracking and isomerization reaction of Fischer-Tropsch syncrude process, reactor development and new catalyst preparation.