溶剂分子在失活ZSM-5催化剂中的扩散行为  

Diffusion behavior of solvent molecules in deactivated ZSM-5 catalyst

作　　者：吕正忠 常素萍 凌嘉俊 王礼云 卜令坤 LV Zhengzhong;CHANG Suping;LING Jiajun;WANG Liyun;BO Lingkun(Ningxia Coal to Oil Chemical Quality Inspection and Measurement Center of National Energy Group,Yinchuan 750411,China)

机构地区：[1]国家能源集团宁夏煤业煤制油化工质检计量中心,宁夏银川750411

出　　处：《石油化工》2025年第3期304-310,共7页Petrochemical Technology

摘　　要：以ZMS-5分子筛为原料制备了不同积碳量的催化剂,利用NMR测试得到自旋-晶格弛豫时间(T_(1))、自旋-自旋弛豫时间(T_(2))、自扩散系数及曲折因子(ξ);分析了积碳催化剂的孔径分布,不同溶剂分子在积碳催化剂中的扩散行为,积碳催化剂中的弛豫行为及积碳对溶剂分子传质性能的影响。表征结果显示,ZSM-5分子筛存在积碳速率较快的非稳态阶段和积碳缓慢的稳态阶段;当庚烷和甲醇作溶剂探针分子时,随着积碳量的增加,T_(1)增加,T_(2)较小,ξ差异不大;而以环己烷为探针分子时,随积碳量的增加,T_(1)减少,T_(2)较大;随溶剂分子尺寸增大,ξ增大;以庚烷、甲醇、环己烷为探针分子,各积碳催化剂上探针分子的自扩散系数差异不大。Catalysts with different amounts of carbon deposition were prepared from ZMS-5 zeolite.The spin-lattice relaxation time(T_(1)),spin-spin relaxation time(T_(2)),self-diffusion coefficient and tortuosity factor(ξ)were obtained by NMR test.The pore size distribution of the carbon deposition catalyst was analyzed.The diffusion behavior of different solvent molecules in carbon deposition catalyst,the relaxation behavior of carbon deposition catalyst,and the influence of carbon deposition on the mass transfer performance of solvent molecules were explored.The characterization results show that ZSM-5 zeolite has a non-steady state stage with a fast carbon deposition rate and a steady state stage with a slow carbon deposition rate.When heptane and methanol are used as solvent probe molecules,with the increase in carbon deposition,T_(1) increases,T_(2) is small,and ξ is basically the same.When cyclohexane serves as a probe molecule,with the increase in carbon deposition,T_(1) decreases,and T_(2) is large.With the increases of molecular size of solvent,ξincreases.When heptane,methanol,and cyclohexane are used as probe molecules,the self-diffusion coefficients of probe molecules in various coked catalysts demonstrated negligible variation.

关 键 词：甲醇制丙烯 催化剂 ZSM-5分子筛 溶剂分子 

分 类 号：TQ426.94[化学工程]