Abstract: A Novel Structure zeolite Y (NSY) composite was modified by twice rear earth exchange and calcination. The crystal structure, surface area, pore volume, chemical compositions, thermal stability and hydrothermal stability of the modified samples were characterized by X-ray diffraction, X-ray fluorescence spectrometer, N2 adsorption, DTA and MAT techniques. Modified samples having various rear earth contents were used to prepared FCC catalysts, the catalytic performances of these catalysts were evaluated using fixed-fluidized bed (FFB) device. Test results showed that modified samples having higher rare earth content exhibited better residue cracking ability and higher light oil yield; modified samples having lower rare earth content exhibited better coke selectivity and higher LPG yield.

Key words: zeolite Y, modification, fluid catalytic cracking