Abstract

The effect of the rare-earth element (REE) content in dual-zeolite cracking catalysts on the conversion of n-dodecane and an n-dodecane–2-methylthiophene mixture (5000 ppm S) has been studied. The catalysts have been synthesized using zeolites Y and ZSM-5 modified with REEs and phosphorus, respectively, as the active component. It has been shown that the presence of REE oxides in zeolite Y (at a constant SiO₂/Al₂O₃ ratio) affects the catalytic activity of cracking catalysts based on this zeolite. The dependence of the light olefin yield on the REE oxide content in zeolite Y passes through a maximum at 2–3 wt %. The presence of a sulfur compound in an amount of 5000 ppm (in terms of sulfur) in the feedstock leads to a decrease in the model hydrocarbon conversion and the C₂–C₄ olefin yield. In the presence of a sulfur compound, the change in the C₂–C₄ olefin yield as a function of REE oxide content in zeolite Y is less pronounced than that in the case of individual n-dodecane cracking.

中文翻译：

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含有不同数量稀土元素的双沸石裂解催化剂存在下的正十二烷与2-甲基噻吩的共转化

摘要

研究了双沸石裂化催化剂中稀土元素（REE）含量对正十二烷和正十二烷-2-甲基噻吩混合物（5000 ppm S）转化的影响。使用分别用REE和磷改性的Y和ZSM-5沸石作为活性组分合成了催化剂。已经表明，沸石Y中存在REE氧化物（SiO ₂ / Al ₂ O ₃恒定）比例）影响基于该沸石的裂化催化剂的催化活性。轻质烯烃产率对沸石Y中REE氧化物含量的依赖性最大达到2-3 wt％。原料中硫化合物的含量为5000 ppm（以硫计）导致模型烃转化率和C ₂ -C ₄烯烃产率降低。在存在硫化合物的情况下，与单独的正十二烷裂解情况相比，沸石Y中C ₂ -C ₄烯烃产率随REE氧化物含量变化的变化不那么明显。