稀土改性L沸石在烃类催化裂化催化剂中的应用

Application of rare earth-modified zeolite L in hydrocarbons cracking catalyst

采用离子交换的方法制备了一系列复合稀土(含La及Ce)质量分数不同的稀土改性超稳L沸石(RE-USL),以RE-USL沸石替代质量分数为5%的REUSY作为催化裂化催化剂的活性组分,用标准轻油微反活性试验(MAT)评价了其催化性能,并同单一稀土元素改性USL沸石进行了对比。结果表明,一定量的复合稀土改性USL沸石的催化性能优于单一稀土(La或Ce)改性的USL沸石,在催化裂化催化剂中加入稀土改性USL沸石,可以降低汽油产品的烯烃质量分数;可以提高汽油的辛烷值。当复合稀土在RE-USL沸石中的质量分数为0.4%左右时,与不加稀土改性USL沸石催化剂相比较,催化剂的活性指数MAT提高3.6个单位,烯烃质量分数降低1.57个单位,研究法辛烷值(RON)提高2.08个单位,产品分布更合理。

Zeolite RE-USL（ultra stable zeolite L modified by rare earth ions） with different contents of composite rare earth（La and Ce） was prepared by ion-exchange,substituted for REUSY of 5% as an active additive component of catalytic cracking catalyst.The catalytic cracking performance of the catalysts with the RE-USL zeolites was evaluated by micro-activity testing（MAT） using diesel oil as a feedstock,and compared with the catalyst containing the zeolite USL modified by single rare earth element of La or Ce.The results show that the performance of the catalyst added zeolite USL modified by a proper amount of composite rare earth into the FCC catalyst is superior to zeolite USL modified by single rare earth element.The new catalyst can decrease the content of olefins in gasoline and increase octane number of gasoline.When composite rare earth content in zeolite RE-USL is about 0.4%,compared with catalyst without zeolite RE-USL,MAT index increases 3.6 units,the content of olefins decreases 1.57 units,research octane number（RON） increases 2.08 units,and catalytic product distributions are more excellent.