ESR-GC法研究沸石催化剂的积炭与失活

STUDY ON THE COKE FORMATION AND DEACTIVATION OF ZEOLITE CATALYSTS BY ESR-GC TECHNIQUE

用ESR-GC-computer联机的动态装置,研究了HM,Al-Cl-M和HZSM-5沸石催化剂在固定床微型石英反应器中400℃催化正己烷裂化反应的积炭和失活行为。由于观测时间不同,在HM和HZSM-5发现了两种变化规律相反的ESR谱图。借助于ESR准原位测试得到了与C_c=At^n方程一致的模拟方程E_c=Bt^m。对三种催化剂观测到相同ESR幅值对应着不同的积炭量,这意味着来自三种催化剂的不同反应物种对ESR幅值贡献不同。由GC-Computer观测到酸性催化剂的失活主要是因为生成焦炭,其反应的活性中心即是积炭的部位。用ESR-GC法研究催化剂的积炭和失活是一种有效的方法。

The coke formation and deactivation of HM, A1-C1-M and HZSM-5 zeolite catalysts for n-hexane cracking reaction were studied at 400℃ in a fixed-bed micro-type quartz reactor with a dynamic state equipment of combined ESR-GC-Computer. It is found that there are two kinds of ESR spectra in opposite pattern varied with the change of observation time on HM and HZSM-5. A simulated equation Ec= Btm coincided with Cc = At is obtained by means of in psudo- situ ESR measurement. The equivalent ESR amplitude in relation to different amount of coke formation is observed, on three catalysts, it means that the different reactant species from three catalysts make different contributions to ESR amplitude. GC-Computer confirms that the deactivation of acidic catalysts is mainly clue to the coke formation and that the reactant active site is exactly the site of coke formation.