磷改性Y型分子筛的氢转移性能考察

INVESTIGATION ON HYDROGEN TRANSFER PROPERTIES OF Y ZEOLITE MODIFIED WITH PHOSPHORUS

以正十二烷为模型化合物 ,考察了不同类型分子筛和不同Y型分子筛的氢转移性能及其对裂化产物中液相烯烃产率的影响。结果表明 ,HY分子筛以具有更适合双分子氢转移反应的特点而具有最高的氢转移性能和最好的降烯烃效果。Y型分子筛中较高的稀土质量分数会促进分子筛的氢转移催化性能 ,但引起焦炭产率增加。含稀土分子筛的磷改性可以调变其表面酸性。磷改性后的分子筛不但具有良好的焦炭选择性 ,同时具有更好的氢转移性能 ,在此基础上提出了“选择性氢转移反应”

Hydrogen transfer activity of different zeolites and different Y zeolites has been studied in the catalytic cracking of dodecane. HY zeolite was the best in its hydrogen transfer activity as compared with HZSM 5 and H β due to its better suitability for bimolecular reactions than the other two zeolites. Higher content of rare earth in zeolites promoted hydrogen transfer reactions over zeolites, however, it also promoted the coke make. The addition of phosphorus optimized the acidity of the zeolite, maintaining lower coke yield while increasing hydrogen transfer reactions. This kind of hydrogen transfer reactions is defined as 'selective hydrogen transfer reactions'.