磷改性ZSM-5及其对催化裂化增产丙烯的影响

对催化裂化（FCC）催化剂/助剂进行功能改性是提高丙烯产量、助力炼油厂转型升级的一种简单有效的方法。制备了经过碱处理和不同含量磷改性的ZSM-5分子筛xP/A/ZSM-5，x表示分子筛磷负载量（以P₂O₅质量分数计），%]，将其用于FCC增产丙烯。采用X射线衍射、透射电镜、³¹P固体核磁共振和X射线光电子能谱等表征方法对改性样品的结构、酸性和磷存在形态进行表征，并对其在FCC过程中增产丙烯的性能进行研究。结果表明，所有改性后ZSM-5作用下的丙烯收率均优于改性前ZSM-5分子筛，这与孔体积减小和酸度变化有关。在测试的助剂中，8.0P/A/ZSM-5样品的催化性能最好，丙烯收率为8.62%。对磷与ZSM-5分子筛相互作用机理的研究表明，磷能与骨架铝和非骨架铝相互作用形成AlPO₄物种，并在磷改性分子筛表面检测到了AlPO₄物种。

EFFECT OF PHOSPHORUS MODIFICATION ON THE ZSM-5 ZEOLITE FOR INCREASING PROPYLENE PRODUCTION IN FCC UNIT

Direct functional modification of fluid catalytic cracking (FCC) catalyst additives is a simple and effective method for increasing propylene production. ZSM-5 modified by alkali and different content of phosphorus named XP/A/ZSM-5 was prepared for increasing propylene production in FCC unit,in which x means the loading amount of phosphorus (calculated by the mass fraction of P₂O₅,%) . The structure, acidity and phosphorus forms of modified samples were characterized by XRD, TEM, ³¹P NMR and XPS. The performance of increasing propylene production in FCC process was studied. The results show that the propylene yield of all phosphorus modified samples is better than that of ZSM-5, which is related to the decrease of pore volume and acidity. Among the tested additives, 8.0 P/A/ZSM-5 sample had the best catalytic performance, and the yield of propylene was 8.62%. The interaction mechanism of phosphorus and ZSM-5 zeolites showed that phosphorus could interact with framework aluminum and non-framework aluminum to form AlPO₄ species which were detected on the surface of phosphorus modified zeolites.