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Mo/HZSM-5催化剂上甲烷芳构化反应行为的改善—催化剂制备因素及反应物添加剂的考察
Improvement of Methane Dehydroaromatization Performance over Mo/HZSM-5 Catalyst-Effects of Catalyst Preparation Methods and Reactant Additives
【摘要】 考察了6Mo/HZSM-5催化剂的不同制备因素对其甲烷芳构化反应性能的影响,包括甲烷气氛下以不同的程序升温速率(从600℃到700℃)预还原催化剂,及采用热溶液(70~80℃)浸渍制备催化剂等方法.在t=700℃,P=0.1MPa,SV=1500mL/(g-cat·h)的反应条件下,发现适当的程序升温速率预还原和热溶液浸渍制备等方法可以改善6Mo/HZSM-5催化剂的甲烷芳构化反应性能,提高催化剂的反应活性及稳定性.同时还考察了1.5%二甲醚作为反应物添加剂在不同反应温度、不同Mo担载量的HZSM-5催化剂上的甲烷芳构化反应性能,并与CO2,H2O的反应结果进行了对比.实验结果表明,在P=0.1MPa,SV=1500mL/(g-cat·h)的反应条件下,较高的反应温度及适量增加催化剂Mo担载量有利于进一步改善1.5%二甲醚/甲烷共进料情况下的芳构化反应行为;反应6h后催化剂的TEM照片显示,二甲醚与甲烷共进料改变了催化剂上积碳的形貌.
【Abstract】 Methane aromatization performance of different 6Mo/HZSM\|5 catalysts, which were prepared by changing the conditions of preparation, was investigated under the reaction conditions of t=700 ℃, P=0.1 MPa, SV=1 500 mL/(g-cat·h). It was found that the catalysts prepared by reducing Mo/HZSM-5 in CH4 stream at a slower heating rate from 600 ℃ to 700 ℃ or by impregnating HZSM-5 power in hot (NH4)6Mo7O24 solution (70 80 ℃) had a better catalytic activity and stability. The effects of 1.5% dimethyl ether (DME) as reactant additive to CH4 feed were also investigated over Mo/HZSM-5 catalysts with different Mo loadings and at different temperatures. The results showed that higher reaction temperatures and higher Mo loadings were in favor of the aromatization of 1.5%DME/CH4 co-feed under the reaction conditions of P=0.1 MPa and SV=1 500 mL/(g-cat·h). The TEM images of 6Mo/HZSM-5 catalysts coked for 6 h showed that the appearance of the coke was changed by 1.5%DME/CH4 co-feed. The effects of 1.5% H2O and 2.5% CO2 co-reactants were also investigated and compared.
【Key words】 Mo/HZSM-5; Methane aromatization; Dimethyl ether (DME); CO2; H2O;
- 【文献出处】 分子催化 ,Journal of Molecular Catalysis , 编辑部邮箱 ,2005年02期
- 【分类号】O643.3
- 【被引频次】4
- 【下载频次】226