高岭土微球 细粉混合晶化制备高结晶度Y分子筛

PREPARATION OF Y ZEOLITE WITH HIGH CRYSTALLINITY BY MIXING KAOLIN MICROSPHERES AND POWDER

采用高岭土微球、细粉为原料,分别经过高温和中温焙烧得到相应的高土微球细粉、偏土细粉微球,通过微球、细粉混合原位晶化的方式,合成了Y分子筛,并采用X射线衍射、N 2吸附-脱附、扫描电子显微镜进行了表征。结果表明:高土和偏土混合晶化中,偏土晶化产物具有更高的结晶度;在液固质量比为2.5、高土微球和偏土细粉质量比为1∶1时,分离得到的偏土晶化产物(命名为PK-1)Y分子筛结晶度可达81%,介孔孔体积和外比表面积分别为0.13 cm^(3)/g和53.3 m^(2)/g,高于对比工业NaY分子筛的0.02 cm^(3)/g和28.8 m^(2)/g;PK-1的晶体粒度为300~600 nm。ACE评价结果显示,与工业NaY分子筛相比,采用PK-1所制备的催化剂具有更好的重油转化能力和更优的焦炭选择性。

Kaolin microsphere(or powder)and metakaolin powder(or microsphere)were used as raw materials,the corresponding kaolin microsphere and metakaolin powder were obtained by high temperature and medium temperature calcination respectively.Y zeolite was synthesized and characterized by XRD,N_(2) adsorption-desorption and SEM.The results showed that the crystallinity of metakaolin was higher in the mixed crystallization of kaolin and metakaolin.When the mass ratio of liquid to solid was 2.5 and the mass ratio of kaolin microsphere to metakaolin powder was 1∶1,the crystallinity of the metakaolin product(named PK-1)was 81%,and the mesoporous pore volume and external surface area were 0.13 cm^(3)/g and 53.3 m^(2)/g respectively,which were higher than those of NaY(0.02 cm^(3)/g and 28.8 m^(2)/g).The grain size of PK-1 was 300—600 nm.ACE evaluation showed that the catalyst prepared by using PK-1 had better heavy oil conversion ability and better coke selectivity than by commercial NaY zeolite.