A modification method of in-situ crystallization type catalytic cracking catalyst

Abstract

A method for modifying an in-situ crystallization type catalytic cracking catalyst. The method is to firstly treat the crystallized product of the in-situ crystallization type FCC catalyst with alkali under hydrothermal conditions, then exchange four times with ammonium ions and rare earth ions, and roast twice to obtain the desired catalyst product. . In the alkali treatment, the amount of alkali added is such that the weight ratio of alkali / crystallized product is 0.01-0.15, the reaction temperature is 70-100° C., and the treatment time is 0.1-3 hours. The method does not increase the modification cost of the catalyst, and greatly reduces the amount of ammonium salt used, thereby reducing the burden and investment in the treatment process of ammonia-nitrogen-polluted primary ammonia-nitrogen wastewater. It is an environmental protection technology in catalyst production; the prepared catalyst has relatively high With low sodium oxide content, the pore volume increases, and the catalyst performance remains basically unchanged or improved.

Description

technical field [0001] The invention relates to a modification method of a catalytic cracking catalyst, in particular to a modification method of an in-situ crystallization type catalytic cracking catalyst. Background technique [0002] In FCC catalysts, sodium oxide will seriously affect the activity, selectivity and stability of the catalyst, so the content of sodium oxide in the catalyst is strictly limited. At present, FCC catalysts include all clay catalytic cracking catalysts (in situ crystallization catalysts), semi-synthetic catalysts and fully synthetic catalysts. The in-situ crystallization catalyst uses a one-step method to prepare the molecular sieve and the matrix, which is convenient and quick, but the sodium oxide is distributed in the matrix and the molecular sieve at the same time, which greatly increases the difficulty of reducing the sodium oxide. For this reason, people use ion exchange to reduce the content of sodium oxide in the catalyst, thereby prepa...

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Problems solved by technology

The raw material processed in the method disclosed in this patent application is NaY molecular sieve synthesized by sol-gel, and in this method, NaY molecular sieve needs beating treatment before alkali washing, and the process is relatively cumbersome, and this method will increase the difficulty of NaY filtration and water washing. Therefore, it is not easy to realize in industrial production

[0009] U.S. Patent No. 3,326,797 also proposes a method for alkali treatment of molecular sieves: the equivalent molar concentration of hydroxide is 0.1 to 15 mol / L, the temperature is 0 to 100°C, and the time is 5 minutes to 5 hours. The alkali treatment in the method is mainly to extract Skeleton silicon in molecular sieves, this method only deals with molecular sieves with a silicon-aluminum ratio of 6-12, and is not applicable to molecular sieves with a ratio of less than 6

For in-situ crystallization products, when the concentration of sodium hydroxide in the solution exceeds 3mol / L and the time exceeds 3 hours, it is easy to cause the microsphere strength of the crystallization product to decrease, and the crystallinity of the molecular sieve will decrease more. When the temperature is 0 ~60°C or when the concentration of sodium hydroxide is less than 0.2mol / L, it has little effect on the matrix of the in-situ crystallization product and cannot achieve the desired effect

[0010] According to the existing technology, the ammonium salt used in the modification of the in-situ crystallization type catalytic cracking catalyst is too large, and the activity and selectivity of the catalyst cannot be significantly improved.

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