Abstract:

Through impregnation and hydrothermal synthesis method, another metal Pd was doped into the Pt/KL catalyst to carry on the modification. The results show that two different ways of introducing Pd have little effect on the crystal structure and pore size distribution of the molecular sieve, but have relatively remarkable influence on its surface acidity. In the fixedbed microreactor, the influences of Pd doping methods on the Pt/KL catalyst activity of n-hexane aromatization and sulfur resistance performance were investigated. The results show that the impregnation method of doping metal Pd can bring more improvement of n-hexane aromatization reactivity, selectivity of aromatic hydrocarbon and sulfur resistance than the hydrothermal method. The analysis indicates that the PtPd/KL catalyst prepared by impregnation enhances metallicity via interaction of Pd and Pt, hence enhances the aromatization activity and sulfur resistance; while Pd in the Pt/Pd KL catalysts prepared by hydrothermal synthesis method enhances the acidity of the catalyst and reduces the aromatization activity and sulfur resistant ability of the catalyst.

Key words:  palladium, platinum, KL zeolite, aromatization, sulphur-resistance