Pt(Pd)/Hβ催化剂催化正丁烷异构化反应特性的研究

Performance of Pt(Pd)/Hβ Catalysts in n-Butane Isomerization

用等体积浸渍法制备了Pt/Hβ和Pd/Hβ催化剂,采用高压连续微反装置在反应温度300～500℃、反应压力2.0 MPa、氢与烃的摩尔比3.0、液态空速1.25 h-1的条件下考察了催化剂催化正丁烷异构化反应的性能;采用N2吸附-脱附和SEM方法对催化剂进行了表征。实验结果表明,反应温度为350℃时,Pd/Hβ催化剂的性能优于Pt/Hβ催化剂;反应温度为400℃时,后者的性能优于前者。反应温度为400℃时,Pt/Hβ催化剂的适宜Pt负载量为0.6%(w),此时正丁烷转化率为65.6%,异丁烷选择性为55.6%;Pd/Hβ催化剂的适宜Pd负载量为0.3%(w),此时正丁烷转化率为64.6%,异丁烷选择性为44.8%。考察了助剂对Pt/Hβ和Pd/Hβ催化剂性能的影响,添加Cu,Sn,Zn的催化剂性能良好。

Pt/Hβ and Pd/Hβ catalysts were prepared by incipient wet impregnation method with shaped Hβ zeolite as the support. Their catalytic performances in n-butane isomerization were studied in a continuous flow microreactor under the conditions of reaction pressure 2. 0 MPa, reaction temperature 300 - 500 ℃, H2/C mole ratio 3.0 and LHSV 1.25 h - 1. The catalysts were characterized by means of Nz adsorption-desorption and SEM. The results showed that the isomerization performance of Pd/Hβ catalyst was better than that of Pt/Hβ catalyst at 350 ℃ and quite the contrary at 400℃. Under reaction temperature 400 ℃ and appropriate Pt loading on Pt/Hβ catalyst 0. 6% （w）, its catalytic performance was best, and the conversion of n-butane and the selectivity to i-butane could reach 65.6% and 55.6% respectively; at Pd loading on Pd/Hβ catalyst 0.3% （w）, its catalytic performance was best, the conversion of n-butane and the selectivity to i-butane were 64.6% and 44.8% respectively. The performances of the Pt/Hβ and Pd/Hβ catalysts could were improved by addition of Cu, Sn and Zn additives.