摘要
对甲苯歧化与三甲苯烷基转移反应体系中不同温度和进料条件下的平衡组成、平衡转化率、平衡选择率进行了详细计算。结果表明:(1)随温度的升高,甲苯与三甲苯的芳烃平衡转化率降低,二甲苯的平衡选择率亦降低;(2)降低进料中的甲苯与三甲苯摩尔比(Tol∶TMB从9降到1),甲苯和三甲苯的芳烃平衡转化率降低,而二甲苯的平衡选择率明显上升。然后,在改性的β沸石催化剂上进行了不同工艺条件下的反应,通过对实验数据与平衡数据的比较和分析表明,反应温度升高,芳烃转化率上升且越来越接近平衡转化率,而二甲苯的选择率迅速下降;进料中Tol∶TMB存在一个最佳点,即60∶40(m∶m),此时芳烃转化率最高,二甲苯的选择率亦最高。
The reaction system of toluene disproportionation and trimethylbenzene transalkylation is a complex system for xylene preparation. In this paper, the equilibrium compositions of the products in this reaction system were carefully calculated and the equilibrium compositions at different temperatures and different feed compositions were analysed. The results show that as the temperature increases, the equilibrium conversions of toluene and trimethylbenzene decrease, and the equilibrium selectivity of xylene decreases as well. As Tol∶TMB value in the feed decreases from 9 to 1, the equilibrium conversions of toluene and trimethylbenzene decrease, while the equilibrium selectivity of xylene increases significantly. These results are due to the cooperation effect of toluene disproportionation and trimethylbenzene transalkylation. Using treated β zeolite as the catalyst, we analysed the reaction results and compared them with calculated equlibrium results. The results show that as the temperature increases, the aromatics conversions increase and approach to the equilibrium value, while xylene selectivity decreases markedly. It shows that there is an optimal point of Tol∶TMB value (60∶40) at which aromatics conversions and xylene selectivities achieve the maximum values.
出处
《华东理工大学学报（自然科学版）》
CAS
CSCD
北大核心
2003年第1期13-16,42,共5页
Journal of East China University of Science and Technology
