改性Mo-Co/HZSM-5催化剂对甲烷无氧芳构化反应的影响

Effect of methane dehydroaromatization over modified 6%Mo-0. 7%Co/HZSM-5 catalysts in absence of oxidants

以6%Mo-0.7%Co/HZSM-5催化剂为基础,分别添加第3金属活性组分Mg、Ni、Zn、Fe,采用共浸渍法制备一系列催化剂,并考察他们对甲烷无氧芳构化催化性能的影响。结果表明,在HZSM-5分子筛上浸渍得到的6%Mo-0.7%Co-0.1%Ni/HZSM-5催化剂与6%Mo-0.7%Co/HZSM-5相比甲烷的最大转化率从12%增加到13.9%,苯收率从6.58%增加到7.05%,同时还提高了催化剂的稳定性,使其失活速率由13.72%/h降低到12.73%/h。NH3-TPD等结果表明,6%Mo-0.7%Co/HZSM-5中添加第3活性组分Ni后,分子筛的酸强度及酸量得到优化,弱酸量与强酸量比例适中。TG的表征进一步说明了Ni物种调节了B酸位与Mo物种之前的相互作用,优化了催化剂的积碳行为。

A series of 6% Mo-0. 7% Co-M/HZSM-5 catalysts （ here M refers to the third metals ： Mg, Ni, Zn, Fe） are made by co-impregnation method. The promotion effect in methane dehydroaromatization in absence of oxidants is evaluated. The results show that compared with 6% Mo-0. 7% Co/HZSM-5 ,the maximum methane conversion rate of 6% Mo-0. 7% Co-0. 1% Ni/HZSM-5 catalyst is increased from 12% to 13.9% and the biggest benzene yield is increased from 6. 58% to 7. 05%. Meanwhile, the stability of catalyst is also improved. The deactivation rate is reduced from 13.72%/h to 12. 73% /h. The result of NH3-TPD shows that after adding the third active component,the amount and the strength of acid are optimized. The volume rate of weak acid and strong acid are suitable. The result of TG illustrates that Ni species modifies the interaction between the Bronsted acid and Mo species and optimized the carbon deposition behavior of the catalyst.