Molecular sieve catalyst for catalytic cracking regenerated flue gas denitrification and preparation method thereof

Abstract

The invention relates to a molecular sieve based catalyst for catalytic cracking regenerated flue gas denitration and a preparation method of the molecular sieve based catalyst. The preparation method is characterized by comprising the steps of firstly adding organic armine into deionized water to obtain a solution A; dissolving salt containing heteroatom in the deionized water to obtain a solution B; mixing the solution A and the solution B to obtain a mixed solution, adding an aluminum source into the mixed solution, adding a silicon source into the mixed solution, crystallizing the mixed solution in two stages under a temperature variable condition, centrifugally separating the crystallized solution, washing lower layer solids by utilizing alcohol, drying and roasting the solids, carrying out interchanging by utilizing ammonium nitrate, and roasting the solids again to obtain a product, wherein the heteroatom is Cu, Mo, La or Ce; the molar ratio of Si to the heteroatom is 200 to 10; a low temperature interval of the temperature variation in the two stages is 90 to 120 DEG C, and a high temperature interval of the temperature variation in the two stages is 160 to 190 DEG C; a molar ratio of SiO2 to Al2O3 is (100: 1) to (20: 1). The molecular sieve based catalyst is applied to the FCC regenerated flue gas denitration SCR reaction, the preparation time is short, the reaction activity is relatively high, and the application prospect is relatively good.

Description

technical field [0001] The invention relates to FCC regeneration flue gas denitrification technology, in particular to a molecular sieve-based catalyst for denitrification of FCC regeneration flue gas and a preparation method thereof, belonging to the technical field of environmental protection. Background technique [0002] Catalytic cracking (FCC) unit is an important unit in the deep processing of crude oil, and occupies a pivotal position in the oil refining industry. During the catalytic cracking reaction, when the raw oil cracks, 30% to 50% of the nitrogen-containing compounds enter the oil coke, and then deposit on the surface of the catalyst. The activity of the catalyst is reduced due to the oil coke attached to the surface, so it must be regenerated. During regenerator charring, most of the nitrogenous compounds are converted to N 2 , but 10% to 30% are converted into NOx and discharged with the regeneration flue gas. The main component is NO, the volume percent...

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Problems solved by technology

However, the active components loaded on the ZSM-5 molecular sieve are easy to aggregate during the preparation process, which leads to its inability to be fully utilized, resulting in a waste of resources. At the same time, the aggregates are also easy to cover the acid center, resulting in a decrease in the activity of the catalyst.

Since ordinary ZSM-5 is a micron crystal molecular sieve, its micropores limit the diffusion of NOx in the molecular sieve micropores to a considerable extent, thus greatly limiting the selective catalytic reduction rate of NOx on the microporous molecular sieve catalyst

Moreover, the catalyst preparation cycle is long and the energy consumption is high

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