Catalyst suitable for two-stage catalytic cracking reaction, and preparation method and application thereof

Abstract

A catalyst suitable for a two-stage catalytic cracking reaction, and a preparation method and application thereof. The catalyst is characterized by comprising five-member ring micropores, twelve-member ring micropores and mesopores in a pore volume ratio of 1:9-11:4-6 in a structure, and by being prepared from 2-12wt% of ZSM-5 molecular sieve, 20-45wt% of rare earth Y molecular sieve, 5-15wt% of aluminium sol calculated by Al2O3 and 10-30wt% of pseudo-boehmite, 0.5-5wt% of pore forming agent and the balance of kaolin into microballoons with an average particle size of 50-70mum, through slurryand spray moulding. During beating, 5-30wt% of hydrochloric acid, calculated by dry basis, is added into the pseudo-boehmite, and maintained at 40-90 DEG C for 0.1-2 h; and the rare earth Y molecularsieve contains 1-16wt% of oxidized rare earth and has a crystal cell of 2.450-2.470 nm. When applied to a catalytic cracking apparatus, in which a second stage reaction temperature is 10-35 DEG C lower than that of the first stage and an oil agent contact time of a second stage reaction is 3-6 times longer than that of the first stage, the catalyst has advantages of low oil slurry yield, high light hydrocarbon liquid yield and low sulfur and alkene in gasoline fraction.

Description

technical field [0001] The invention relates to a catalyst for catalytic cracking of petroleum hydrocarbons, in particular to a catalyst suitable for two-stage catalytic cracking reaction and its preparation method and application, belonging to the field of petrochemical catalysts. Background technique [0002] With the increasing emphasis on environmental protection, the problem of automobile exhaust pollution has attracted more and more attention from all countries in the world. For this reason, the olefin content and sulfur content of unleaded gasoline for vehicles have been restricted in the "Standard for Unleaded Gasoline for Vehicles (GB17930-1999)" issued by the State Bureau of Quality and Technical Supervision. Most of the components in blended gasoline are still produced by catalytic cracking units. Catalytic cracking is also the most important means of lightening heavy oil. Its reactors have undergone fixed bed, moving bed, fluidized bed, riser and other Variation...

AI Technical Summary

Problems solved by technology

Other existing technologies with multi-section reactor forms include CN1091393C, CN1364854A, CN1340593A, CN1340594A, CN100377774C, CN2214222Y, USP6106697, CN100586909C, CN101191068A, etc. There is no essential difference in principle, but because the structure is too complicated Or there is no big difference in the implementation effect and other reasons, so it has not been well applied in practice

[0007] The heavy oil catalytic cracking catalyst generally adopted on the catalytic cracking unit at present, as disclosed in CN1733362, CN1733363, CN101386788, CN101385983 etc., in order to maintain the conversion efficiency of heavy feedstock has kept very high cracking activity, but the selectivity of cracking product is not Not good, when used in a catalytic cracking unit with zonal reaction characteristics, it is difficult to take into account the different performance requirements of the catalyst in two different reaction zones, and there are often defects such as high coke and dry gas yields, poor product distribution, etc.

CN1157259C, CN1124892C disclose the cracking catalyst of prolific isoparaffins, adopted two kinds of high silicon Y zeolites to improve the selectivity of isoparaffins in the product gasoline, but in actual use, there is not enough conversion depth of heavy oil, and the light product is Disadvantages of low hydrocarbon yield

CN1607239A, CN1607241A, and CN1281716C disclose catalytic cracking methods with two reaction zones and adopt a catalyst with desulfurization performance. Because it adopts a metal oxide with desulfurization function, it weakens the acid center on the catalyst, resulting in heavy oil conversion of the catalyst Obvious lack of ability

Choose to have the largest yield of light hydrocarbons (liquefied petroleum gas, gasoline and diesel oil), or for catalytic cracking units with zonal reaction characteristics, with specific pore volume gradient distribution, strong conversion ability of heavy oil, high total liquid yield of light hydrocarbons and product gasoline fraction A cracking catalyst with medium sulfur and low olefins has not been reported in the prior art