FIELD: catalytic chemistry.
SUBSTANCE: molecular sieve proposed according to the invention contains rare earth elements and phosphorus, has an MFI structure and a high mesopore content, in which there is a silicon component, an aluminium component, a phosphorus component and a supported metal component, and the molecular sieve has a ratio of n(SiO2)/n(Al2O3), which is more than 15 and less than 70; the molecular sieve has a phosphorus content, calculated as P2O5, ranging from 1 to 15 wt%, based on the dry weight of the molecular sieve; wherein the molecular sieve has a supported metal content in terms of oxide of the supported metal, comprising from 1 to 10 wt% of the supported metal M1 and from 0.1 to 5 wt% of the supported metal M2 in relation to the dry weight of the molecular sieve, and the supported metal M1 is one or more metals selected from rare earth elements and the supported metal M2 is one metal selected from iron, cobalt, nickel, copper, manganese, zinc, tin, bismuth and gallium; wherein the mesopore volume of the molecular sieve is 40 to 70% by volume with respect to the total pore volume of the molecular sieve, the mesopore volume and the total pore volume of the molecular sieve being measured by nitrogen adsorption to calculate the Brunauer-Emmett-Teller specific surface area (BET), and mesopore volume means the pore volume for pores having a diameter of more than 2 nm and less than 100 nm, and the molecular sieve has an RE distribution parameter D that satisfies the following conditions: 0.9≤ D ≤ 1,3, and D = RE(S)/RE(C), where RE(S) is the content of rare earth elements in any area that is more than 100 nm2 and located at a distance H in the direction inward from the edge of the crystal face of the crystal molecular sieve grains as measured by Transmission Electron Microscopy-Energy Dispersive X-ray Spectroscopy (TEM-EDS), and RE(C) is the content of rare earth elements in any region greater than 100 nm2 and located at a distance H outward from the geometric centre crystal face of a crystal grain of a molecular sieve as measured by TEM-EDS, wherein H is 10% of the distance from a certain point on the edge of the crystal face to the geometric centre of the crystal face. The invention also relates to a method for producing a molecular sieve, a catalytic cracking catalyst and a method for producing the same, as well as to a method for catalytically cracking a hydrocarbon oil.
EFFECT: excellent yield of ethylene and, at the same time, a high yield of propylene, as well as benzene, toluene and xylenes (BTX) in the catalytic cracking of petroleum hydrocarbons.
28 cl, 11 tbl, 40 ex
