Mo/HZSM-5催化剂上甲烷无氧芳构化反应中积炭的研究  

Study of Coke Deposition on Mo/HZSM-5 Catalyst in Methane Dehydro-Aromatization under Non-oxidative Conditions

作　　者：刘红梅[1] 李涛[1] 田丙伦[1] 徐奕德[1] 

机构地区：[1]中国科学院大连化学物理研究所催化基础国家重点实验室,大连116023

出　　处：《催化学报》2001年第4期373-376,共4页

基　　金：国家重点基础研究发展规划项目 (G19990 2 2 40 0 )

摘　　要：对经过程序升温表面甲烷无氧芳构化反应后的Mo/HZSM 5催化剂上的积炭进行程序升温加氢反应和程序升温二氧化碳反应 ,并对相应的催化剂上的积炭进行程序升温氧化反应和热重实验 ,以研究催化剂上的不同积炭物种 .结果表明 ,甲烷无氧芳构化反应后有两类烧炭峰 ,一类是低温烧炭峰 ,另一类是高温烧炭峰 ;H2 主要对高温烧炭峰发生作用 ,对低温烧炭峰几乎没有影响 ;CO2 可同时对两种烧炭峰产生影响 .由此推论 ,甲烷在无氧条件下直接转化生成芳烃的反应过程中 ,沉积在Mo/HZSM 5催化剂上的积炭有三种形式 ,即 :能够与H2 反应的积炭 ,能够与CO2 反应的积炭和可能以Mo2 C形式存在的物种 .The results of TPH (temperature-programmed hydrogenation), TPCO2 (temperature-programmed CO2 reaction) and TPO (temperature-programmed oxidation) for the 6% Mo/HZSM-5 catalyst after TPSR (temperature-programmed surface reaction) illustrated that various coke deposits are formed during the reaction of methane dehydro-aromatization in the absence of oxygen. The TPO profiles of the coked catalyst showed two peaks. The TPH experiment resulted in the decrease of the area of the peak at high temperature, but had no effect on the area of the peak at low temperature. Meanwhile, the TPCO2 experiment exhibited obvious decrease of the both peak areas. On the basis of TPSR, TPH and TPCO2 experiments and the corresponding TG (thermogravimetry), the quantitative analysis of the coke amount was proceeded. The results showed that there are three types of coke deposits. One can mainly react with H-2, the other can be eliminated by CO2, and the third one may exist in Mo2C, an active species for the title reaction.

关 键 词：甲烷 脱氢芳构化 Mo/HZSM-5沸石 程序升温反应 积炭 钼 HZSM-5沸石 负载型催化剂 

分 类 号：O643.3[理学—物理化学]