用于甲烷脱氢芳构化反应Mo基催化剂的研究  

Study of Mo-Based Catalysts for Dehydro-aromatization of Methane

作　　者：叶飞[1] 余林[1] 宋一兵[1] 孙长勇[1] 方奕文[1] 郝志峰[1] 林维明[2] 徐奕德[3] 林励吾[3] 

机构地区：[1]汕头大学化学系,广东汕头515063 [2]华南理工大学化工系,广东广州510641 [3]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,辽宁大连116023

出　　处：《催化学报》2003年第3期198-202,共5页

基　　金：国家自然科学基金 ( 2 0 14 30 0 4);广东省自然科学基金 ( 0 115 73)资助项目

摘　　要：通过对分子筛载体HZSM 5进行精密前处理 ,然后浸渍钼酸铵溶液和添加微量助剂Fe ,分别制得催化剂Mo HZSM 5(t)和Fe Mo HZSM 5 (t) ,考察了它们对甲烷脱氢芳构化反应的催化性能 .结果表明 ,在Mo HZSM 5 (t)催化剂上 ,反应 5h后 ,甲烷的转化率可达 11 4% ,苯收率高于 6 2 % ,在反应 3 0h后 ,甲烷的转化率可达 8 8% ,苯收率高于 5 3 % ,催化剂显示出较高的稳定性 .微量助剂Fe的添加在保持催化剂稳定性的前提下进一步改善了催化剂的活性 ,使甲烷的转化率相对于Mo HZSM 5 (t)上的提高了 18% ,苯收率提高了 5 2 % .XRD和TPO测试表明活性组分Mo和助剂Fe高度分散于载体上或进入载体孔道中 ,载体的精密前处理及Fe的添加提高了催化剂的抗积炭能力 。Methane dehydro-aromatization over Mo/HZSM-5 catalyst has been widely studied in recent years. One of the main problems for the industrial application is the short lifetime of the catalyst owing to the serious carbon deposit on the catalyst surface. The addition of CO or CO_2 in feed as well as the steaming-dealumination and the silanization of the support was used to enhance the stability of the catalyst. In order to effectively suppress the formation of carbon deposit, we designed an easy and special route to prepare the Mo/HZSM-5(t) catalyst, in which HZSM-5 was precisely pretreated by calcination in air at 400 ℃ for 4 h , then re-calcination in N_2 at 500 ℃ for 4 h (precise pretreatment of support) before impregnation with ammonium molybdate. The precise pretreatment was found to be able to significantly improve the activity and the stability of the catalyst. On Mo/HZSM-5(t), the methane conversion and benzene yield even remained at 8.8% and 5.3% respectively after 30 h. Addition of promoter Fe leads to a significant increase in methane conversion and the selectivity for benzene, and methane conversion and benzene yield increase by 18% and 52% respectively, compared with Mo/HZSM-5(t). Through XRD and TPO characterization, it is concluded that Mo and Fe species are highly dispersed on the surface of the support or migrate into the channels of the support. The precise pretreatment of support and the addition of Fe restrain carbon deposit, hence the catalysts with high stability can be obtained.

关 键 词：脱氢芳构化反应 Mo基催化剂 甲烷 HZSM-5沸石 精密前处理 积炭 铁 钼 

分 类 号：O643.3[理学—物理化学]