| abstract |
Disclosed is a modified Y-type molecular sieve having high stability, and the preparation and the use thereof. On a dry basis and using the weight of the modified Y-type molecular sieve as a reference, the modified metal content of the modified Y-type molecular sieve is approximately 0.5-6.3 wt% calculated in terms of a modified metal oxide, and the sodium content thereof is not more than approximately 0.5 wt% calculated in terms of sodium oxide, wherein the modified metal is magnesium and/or calcium. The non-skeleton aluminium percentage content of the modified Y-type molecular sieve is not higher than approximately 20% with respect to the total content of aluminum; the total pore volume thereof is approximately 0.33-0.39 mL/g, wherein the percentage of the pore volume of secondary pores with a pore diameter of 2-100 nm is approximately 10%-25% with respect to the total pore volume; the lattice constant thereof is approximately 2.440-2.455 nm; and the lattice collapsing temperature thereof is not lower than approximately 1040ºC. Moreover, the ratio of the amount of the B acid to that of the L acid in the total acid amount determined at 200ºC using a pyridine adsorption infrared method is not less than approximately 2.30. When used for the catalytic cracking of a heavy oil, the modified Y-type molecular sieve and a catalyst containing same have a lower coke selectivity, and can result in a higher gasoline yield and liquefied gas yield, and the resulting gasoline has a higher isomeric hydrocarbon content. |