Mg对Cr2O3/Al2O3催化剂及其丙烷脱氢性能的影响

制备了不同Mg含量的Cr2O3-MgO/Al2O3催化剂，考察了Mg含量对Cr2O3/Al2O3催化剂丙烷脱氢反应性能的影响，并通过低温N2吸附-脱附、XRF、XRD、NH3-TPD、H2-TPR和SEM等手段对催化剂进行了表征。结果表明：MgO的加入能提高丙烷脱氢反应中的丙烯选择性，主要原因是MgO的加入使载体表面酸量减少，调变了催化剂中Cr价态的分布，并使Cr晶粒变小，更好地分散在载体上；Cr2O3-MgO/Al2O3催化剂中Cr2O3负载量（w）为18%时，MgO负载量（w）为1%~2%较为适宜，催化剂的性能可达到最佳，在反应条件下3 h内，丙烷平均转化率为33%，丙烯选择性为93%。

INFLUENCE OF Mg ADDITION ON PROPANE DEHYDROGENATION PROPERTIES OF Cr2O3/Al2O3 CATALYST

The influence of different Mg content of Cr2O3/Al2O3 catalysts for propane dehydrogenation reaction was investigated. The catalysts were characterized by N2 adsorption at low temperature，XRF，XRD，NH3-TPD，H2-TPR and SEM , to discuss the influence of different Mg content of Cr2O3/Al2O3 catalysts to catalyst physical structure, acidity, crystal type and valence state. Results showed that the major reason for MgO improves the reaction of propylene selectivity is that reducing the carrier surface acid amount, adjusting the valence distribution of Cr in the catalyst, and making the Cr better dispersion on the carrier. If the Cr2O3 content is 18% in the Cr2O3-MgO /Al2O3 catalyst, the appropriate addition of MgO is 1%—2% that catalyst had the best catalytic performance. Under the reaction condition, the propane average conversion of 33% was achieved with the corresponding propylene average selectivity of higher than 93% during reaction for 3 h.