Pd/FER分子筛模板剂脱除及其催化正丁烯骨架异构化反应性能

摘要/Abstract

摘要： 制备HFER-CHA分子筛并进行了钯改性，在不同温度的流动空气气氛下焙烧脱除模板剂，考察钯改性对分子筛模板剂脱除的影响，研究脱除模板剂后的分子筛催化醚后碳四中正丁烯骨架异构化的反应性能。采用X射线荧光光谱（XRF）、X射线衍射（XRD）和氨程序升温脱附（NH₃-TPD）等手段对催化剂进行了表征。结果表明：焙烧温度影响分子筛模板剂的脱除效果和分子筛物理化学性质，钯改性显著降低了HFER分子筛中模板剂的脱除温度，Pd/HFER-CHA分子筛在空气气氛中经350 ℃焙烧4 h即可将模板剂完全脱除；模板剂的脱除增加了分子筛的比表面积和孔体积；随着焙烧温度的提高，分子筛酸量增加，催化剂活性增强，分子筛中L酸的增多是导致醚后碳四中正丁烯发生聚合、裂解等副反应的主要原因；Pd/HFER-350分子筛在350 ℃、0.1 MPa、正丁烯质量空速2.0 h^-1的条件下连续运行720 h，正丁烯平均转化率大于40%，异丁烯选择性大于90%。

关键词: FER分子筛, 钯, 模板剂脱除, 正丁烯, 骨架异构化

Abstract: HFER-CHA was prepared and modified by palladium. The template was removed by calcination in flowing air at different temperatures. The effect of palladium modification on the removal of the template was investigated, and the catalytic performance for the skeletal isomerization of n-butene was studied, and the catalyst was characterized by XRF, XRD and NH₃-TPD, etc. The results showed that the calcination temperature affected the removal efficiency and properties of the zeolite template, and palladium modification significantly reduced the removal temperature of the template in the HFER. The template could be completely removed by calcining Pd/HFER-CHA in air at 350 ℃ for 4 h. The removal of the template increases the specific surface area and pore volume of zeolites. As the calcination temperature increases, the acidity of zeoilites increases, and the catalyst activity rises. The increase in Lewis-acid is the main reason for the side reactions such as polymerization and cracking of n-butene. After the Pd/HFER-350 was continuously operated for 720 h under conditions of 350 ℃, 0.1 MPa, and a mass space velocity of 2.0 h^-1 for n-butene,the average conversion rate of n-butene was greater than 40%, and the selectivity of isobutene was greater than 90%.

Key words: FER zeolite, palladium, templates removal, n-butene, skeletal isomerization

樊金龙朱学栋徐亚荣杨帆. Pd/FER分子筛模板剂脱除及其催化正丁烯骨架异构化反应性能[J]. 石油炼制与化工, 2024, 55(3): 9-20.

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