P-RE-USY沸石的稳定性、酸性和裂化反应特性

采用NH3-TPD、FT-IR、XRD和元素分析方法研究了稀土和磷改性沸石P-RE-USY的酸性、水热稳定性,并在小型固定流化床反应装置中评价了含有这种改性沸石催化剂的反应性能。结果表明,由于磷促进了稀土离子由超笼向方钠石笼中的迁移,阻止了沸石在水热条件下的脱铝作用,从而改善了P-RE-USY沸石的水热稳定性；P-RE-USY沸石酸性分布更集中在中强酸范围,有利于发生氢转移反应,而强酸数量的降低有利于减少焦炭形成,改善了焦炭选择性。评价表明含有这种改性沸石的催化剂显示了优越的降低汽油烯烃的效果,柴油产率可增加2.31%。

ACIDITY AND HYDROTHERMAL STABILITY OF P-RE-USY AND ITS CRAKING REACTION PERFORMANCE

The techniques such as NH_3-TPD, FT-IR, XRD were used to investigate the acid properties and hydrothermal stability of zeolite Y modified with rare earth and phosphorus (P-RE-USY), and the catalyst using P-RE-USY as an active component was evaluated in a small confined fluidized bed apparatus. The results have shown that P-RE-USY has good hydrothermal stability owing to the migration of hydroxy rare earth cation from the super cages to the sodalite cages enhanced by phosphorus addition, inhibiting the framework dealumination of zeolite in the steaming condition. The acid distribution of P-RE-USY is more concentrated in the range of intermediate and strong acidity, improving the hydrogen transfer activity. The reduction of strong acid decreases the formation of coke. The catalyst containing P-RE-USY exhibits excellent performance of reducing naphtha olefins, increasing diesel yield more than 2.31%.