稀土改性MCM-41催化剂在庚烷临氢异构化反应影响因素研究

采用稀土改性MCM-41催化剂进行庚烷临氢异构化反应，通过正交试验设计方法，对影响庚烷转化率和选择性的因素进行了优化设计和实验。结果表明：6个因素影响产物异构选择性的主次顺序为：反应温度＞改性载体的稀土种类＞氢气流速＞催化剂中磷钼酸含量＞催化剂中Ni含量＞还原温度；6个因素影响庚烷转化率的主次顺序为：反应温度＞催化剂中Ni含量＞氢气流速＞催化剂中磷钼酸含量＞还原温度＞改性载体的稀土种类。对正交实验结果进行优化，得到优化方案为：催化剂中Ni质量分数为5%、载体改性稀土为La、反应温度为300 ℃、还原温度为370 ℃、磷钼酸质量分数为20%、H2流速为120 mL/min，在该条件下正庚烷转化率为13.5%、异构庚烷选择性为68%。

STUDY ON THE FACTORS AFFECTING n-HEPTANE HYDROISOMERIZATION OVER RARE EARTH MODIFIED MCM-41 CATALYSTS

Factors affecting the conversion and selectivity of n-heptane hydroisomerization over rare earth modified MCM-41 catalysts were investigated by orthogonal experimental design.Test results showed that the six factors affecting isoheptane selectivity were in the order of reaction temperature>rare earth type in modified support>H2 flow rate>phosphomolybdic acid content in catalyst>Ni content in catalyst>reduction temperature;factors affecting the conversion of n-heptane were in the order of reaction temperature>Ni content in catalyst>H2 flow rate>phosphomolybdic acid content in catalyst>reduction temperature>rare earth type in modified support.The orthogonal test results were further optimized as follows:using La-MCM-41 support,catalyst having Ni mass fraction of 5% and phosphomolybdic acid mass fraction of 20%,H2 flow rate of 120 mL/min,reaction temperature of 300 ℃ and reduction temperature of 370 ℃,under such conditions the conversion of n-heptane was 13.5%,and isoheptane selectivity reached 68%.