A kind of spherical heteroatom ni-sapo-34 molecular sieve and its preparation and application

Abstract

The invention relates to a spherical heteroatom Ni-SAPO-34 molecular sieve, and a preparation method and an application thereof. The preparation method comprises the following synthesis steps: (1) dissolving nickel nitrate hexahydrate in deionized water, and dropwise adding a chelating agent at room temperature while stirring to obtain a Ni chelate solution A; (2) mixing an aluminum source, a phosphorous source, a silicon source, a template and deionized water, and heating and stirring the obtained mixture to obtain an initial sol B; (3) adding the solution A to the initial sol B, and heating and stirring the solution A and the initial sol B to obtain a sol C; and (4) filling a reaction kettle with the sol C, carrying out a crystallization reaction, filtering and washing a product obtained after the reaction is completed until the product is neutral, and drying, calcining and cooling the neutral product to obtain the spherical heteroatom Ni-SAPO-34 molecular sieve. The spherical heteroatom Ni-SAPO-34 molecular sieve with a high crystallinity is synthesized by a sol-hydrothermal synthesis technology, the pressure drop of an accumulated catalyst bed is effectively reduced, the introduction of metallic nickel provides many active sites for the reaction, and the molecular sieve has an important application in an NH3-SCR reaction. The synthesis method has the advantages of simple steps, and easiness in operation.

Description

technical field [0001] The invention belongs to the technical field of synthesis of heteroatom molecular sieves, in particular to a method for synthesizing spherical heteroatom Ni-SAPO-34 molecular sieves. Background technique [0002] Molecular sieves are silicon-phosphorus-aluminum molecular sieves with a CHA topology. Due to their unique pore structure, high specific surface area and moderate acidity, they are widely used in methanol-to-olefin, NH 3 - SCR catalytic reaction. In recent years, in order to improve the catalytic performance of SAPO-34 molecular sieve, many scientific researchers have carried out a series of modified synthesis on SAPO-34 molecular sieve. Among them, the modification of SAPO-34 by using metal ions has attracted extensive attention of researchers. [0003] Liu Hongxing and others used the method of solid-state ion exchange to modify SAPO-34. The analysis results showed that the acidity of SAPO-34 modified with CaO was reduced. Misook Kang syn...

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Problems solved by technology

[0007] The purpose of this invention is to provide a kind of preparation method of spherical heteroatom Ni-SAPO-34 molecular sieve, to solve the problem that the pressure drop of the catalyst bed is too large after the traditional cubic SAPO-34 molecular sieve is piled up, meanwhile, in SAPO-34 molecular sieve Ni elements are introduced into the framework structure to adjust the acid properties (acid type and acid strength) of molecular sieves and improve their catalytic performance

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