Preparation method and application of calcium aluminate catalyst capable of regulating olefin selectivity

Abstract

The invention provides a preparation method of a calcium aluminate catalyst capable of regulating olefin selectivity, and relates to the technical field of heavy oil catalytic cracking. The preparation method comprises the following steps: S1, uniformly dispersing aluminum source powder, calcium source powder and a pore-enlarging agent into a liquid-phase medium to obtain mixed slurry; S2, calcining the mixed slurry obtained in the step S1 for 2-8h at 900-1200 DEG C in an inert gas atmosphere, and then placing the calcined mixed slurry in a mixed gas atmosphere composed of water vapor and oxygen for gasification pore-forming to obtain a calcium aluminate carrier precursor; and S3, uniformly dispersing a modifier and the calcium aluminate carrier precursor prepared in the step S2 in the liquid-phase medium to form homogeneous slurry, drying the homogeneous slurry, roasting the dried homogeneous slurry at 500-700 DEG C for 2-7 hours, and carrying out granulating and screening to obtain the calcium aluminate catalyst. The texture characteristics of the calcium aluminate catalyst obtained by the preparation method provided by the invention are better than those of the catalyst obtainedby the traditional preparation method.

Description

technical field [0001] The invention belongs to the technical field of heavy oil catalytic cracking, and in particular relates to a preparation method and application of a calcium aluminate catalyst capable of regulating olefin selectivity. Background technique [0002] Catalyst is an important factor affecting the efficient conversion of heavy oil. Therefore, the cracking catalyst must have good reactivity, stability, mechanical strength and carbon deposition resistance. So far, the most studied heavy oil conversion catalysts include acid catalysts and basic catalysts. [0003] Acidic catalysts, as the name implies, are catalysts with acidic active centers. In the field of petrochemical industry, molecular sieve catalysts are most commonly used. The surface of this type of catalyst generally has two types of acid centers, Bronsted acid and Lewis acid, which can induce or promote the formation of carbocations in hydrocarbon molecules. In the field of heavy oil catalysis, a...

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Problems solved by technology

People such as Nowak disclosed on the 103-127 pages of the 1989 No. 53 issue of "Surface Science and Catalysis Research" that gas oil was used as a raw material, and calcium aluminate was used as a catalyst to catalyze the conversion of heavy oil raw materials to prepare light olefins. According to the route, the study found that factors such as reaction temperature and catalyst addition ratio have a significant impact on the yield of low-carbon olefins, light oil and aromatics in the cracking products, but the catalyst needs to be synthesized at high temperature, high energy consumption, lack of texture characteristics, and low-carbon olefins in the cracking products. Small change in carbene selectivity

Chinese Invention Patent Application No. CN200710099844.6 discloses a steam cracking catalyst and its preparation method and application. The modified calcium aluminate and aluminum-containing compound carrier are used as catalysts for steam cracking of light petroleum raw materials to produce low-carbon olefins. Research It was found that the prepared catalyst had the advantages of high yield of low-carbon olefins, high catalytic activity, suitable pore structure, and high strength in the steam cracking reaction, but the conversion rate of raw oil during the reaction was not high, only 63.3% to 72.3%, and the cracking reaction Relatively high temperature up to 720 ~ 765 ℃

[0007] The calcium aluminate catalysts adopted in the heavy oil catalytic technology disclosed above are all prepared by solid-phase synthesis, and the specific surface area for preparing calcium aluminate is small (2 g –1 ), lack of pore structure and large specificity, it is difficult to maximize its uniform distribution of active components, control of olefin selectivity and fluidization characteristics, which has become a bottleneck that further restricts the industrial application of calcium aluminate catalysts that can control olefin selectivity

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