Pd 掺杂方式对 Pt/KL 分子筛正己烷芳构化及抗硫性能的影响

摘要

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.%以浸渍法和水热合成法向 Pt/KL 催化剂中掺杂金属 Pd,对催化剂进行改性和表征,并在固定床微型反应装置上考察 Pd 掺杂方式对 Pt/KL 催化剂正己烷芳构化性能及抗硫性能的影响。结果表明：不同方式掺杂 Pd 对分子筛的晶体结构和孔径分布等影响较小,对催化剂表面酸碱性质的影响较大；浸渍法掺杂金属 Pd 较水热法更能提高 Pt/KL 催化剂的正己烷芳构化反应活性、芳烃选择性及抗硫性能。这是由于通过浸渍法制备催化剂 Pt-Pd/KL 中的 Pd 与Pt 相互作用增强了催化剂的金属催化功能,使得其芳构化活性和抗硫性增强；通过水热法制备催化剂 Pt/PdKL 中的 Pd 增强了催化剂酸性,从而降低了催化剂芳构化活性和抗硫能力所致。