Influence of Main Components of FCC Catalyst Prepared by Semi Synthetic Method on Its Pore Structure
The pore structure characteristics of the fluid catalytic cracking(FCC)catalyst with rare earth modified Y-type molecular sieves as the key active constituents and its main components were analyzed in-depth by N2 adsorption-desorption method,Hg porosimetry method,scanning electron microscope(SEM)and transmission electron microscope(TEM).Particularly,the effects of three common binders such as aluminum sol,acidified pseudoboehmite and silica sol on the pore structure of catalyst were investigated.The results show that the micropores of FCC-1 catalyst are chiefly generated from the zeolites.The effects of binders on the micropore structure of zeolites include physical plugging and chemical action.When aluminum sol,acidified pseudoboehmite and silica sol are mixed with USY zeolite according to the mass ratio of 1/2,the loss rate of microporous specific surface area of zeolite is 23.0％,14.2％and 7.7％,respectively,indicating the greatest effect of aluminum sol on the micropores of zeolite.The mesopores of FCC-1 catalyst mainly originated from the stacking pores of binder particles,which are related to the size,morphology and stacking mode of binder particles.Aluminum sol,acidified pseudo boehmite and silica sol with the diameter of 1～2 nm,4～5 nm and 10～50 nm respectively are stacked densely in the form of amorphous alumina,granular y-Al2O3,and spherical SiO2 after calcination at 500 ℃;for particle stacking pores,the most probable pore size are 4.8,5.7 and 7.3 nm,respectively.The macropores of FCC-1 catalyst mainly originated from the piling pores between zeolite and/or Kaolin particles.
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