Composite modified molecular sieve, catalytic cracking catalyst and preparation and application of composite modified molecular sieve and catalytic cracking catalyst

The invention discloses a preparation method of a modified molecular sieve and a catalytic cracking catalyst, which comprises the following steps: (1) preparing a shape-selective cracking molecular sieve, an Ag compound, an Mn compound, a phosphorus compound and deionized water into a mixed slurry with the solid content of 10-65%, stirring for 0.1-5 hours, then filtering, washing, drying or directly drying, and roasting at 300-750 DEG C to obtain a composite modified molecular sieve; and (2) preparing a catalytic cracking catalyst by using the composite modified molecular sieve as a main cracking component. The composite modified molecular sieve and the catalytic cracking catalyst are used for the catalytic cracking reaction of hydrocarbons, can effectively improve the yield of low-carbon olefins such as ethylene and propylene, and show a good effect of reducing methane. 本发明公开了一种改性分子筛及催化裂解催化剂的制备方法，包括：(1)将择形裂化分子筛与Ag化合物、Mn化合物、磷化合物和去离子水制备成固含量为10-65％的混合浆液，搅拌0.1-5h，然后过滤、洗涤、干燥或者直接干燥，经过300-750℃焙烧，获得复合改性分子筛；(2)采用复合改性