Method for preparing nano molecular sieve microspherical catalyst

Abstract

The invention relates to a method for preparing a nano molecular sieve microspherical catalyst. The method comprises the following steps of: mixing pseudo-boehmite, silica solution, phosphoric acid and a template agent in a rotary reaction tank, rotating the rotary reaction tank around a horizontal central shaft, heating and nucleating at the temperature of 100 to 160 DEG C for 2 to 4 hours, adding an abrasion-resistant carrier and water, heating by microwave at the temperature of 150 to 180 DEG C, crystallizing for 40 to 80 minutes, and obtaining the nano molecular sieve microspherical catalyst. Compared with the prior art, the method has the advantages that the process is simple and is suitable for production. The prepared nano molecular sieve microspherical catalyst is high in uniformity and has the characteristics of high specific area and high catalyst activity. The nano molecular sieve microspherical catalyst is applied to reaction of methyl alcohol and dimethyl ether in preparing low-carbon olefin, has the characteristic of low abrasion consumption and is favorable for industrial production.

Description

technical field [0001] The invention relates to a molecular sieve catalyst, in particular to a preparation method of a nano molecular sieve microsphere catalyst. Background technique [0002] Nano-molecular sieves refer to molecular sieves with a particle size between 1-100nm. The ratio of the number of surface atoms to the number of bulk phase atoms increases sharply as the particle size decreases, making nano-molecular sieves a new material with unique catalytic properties. The characteristics of nano-molecular sieves are specifically manifested in: it has a larger outer surface, which exposes more active centers, effectively eliminates the diffusion effect, and enables the catalyst efficiency to be fully exerted; it has more pores exposed to the outside, and is not easy to be reacted Sediment clogging is beneficial to prolong the reaction operation cycle. [0003] The advantages of nano-SAPO-34 molecular sieve are obvious, such as (1) improved diffusion limitation, which...

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Problems solved by technology

[0005] Chinese patent CN1557555A discloses a method for preparing a homogeneous nano-molecular sieve material with high catalytic activity. The patent uses 100-300 nanometer uniform polymer beads in the water phase to form a nano-molecular sieve confined reactor after stirring for a certain period of time. Nano-molecular sieves were synthesized. The molecular sieves prepared by this method are limited to the raw powder of molecular sieves and cannot be directly applied to industrial production.

[0010] There are many patents related to SAPO-34 molecular sieve molding technology, but less about nanometer SAPO-34 molecular sieve molding technology. For example, Chinese patent CN101284246B discloses a catalyst for converting oxygen-containing compounds into low-carbon olefins. The patent points out that in the catalyst The crystal size of 90% of the contained SAPO-34 molecular sieves is less than 0.5 microns, and the grain size of the SAPO-34 molecular sieves is still far behind that of nano-molecular sieves in the strict sense. At the same time, the molding technology adopted is traditional Hybrid bonding molding technology, due to the limitations of this method, the utilization rate of SAPO-34 molecular sieve is also affected to a certain extent, which is not conducive to fully exerting the catalytic performance of SAPO-34 molecular sieve

[0011] Chinese patent CN102219237A discloses a method for preparing a SAPO molecular sieve material with a hierarchical pore structure. The actually obtained monolithic SAPO molecular sieve material with a hierarchical pore structure cannot be directly applied to a fluidized bed process due to its shape and strength.

The reason is that during hydrothermal crystallization, the solid phase carrier in the crystallization mother liquor has uneven mass transfer due to natural settlement, because of the concentration gradient and the liquid-solid separation problem in the reaction process.

It will inevitably lead to performance differences in the synthesized SAPO-34 molecular sieve, and the prepared catalyst cannot achieve the best catalytic performance

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