SSZ-13 molecular sieve catalyst as well as preparation method and application thereof

Abstract

The invention provides an SSZ-13 molecular sieve catalyst as well as a preparation method and application thereof. The preparation method comprises the following steps: adding a sodium source, a silicon source, an aluminum source, a boron source, a template agent and deionized water into a synthesis kettle according to a ratio, then dynamically or statically crystallizing in temperature stages, filtering, washing and drying the product to obtain molecular sieve raw powder; roasting the molecular sieve raw powder at high temperature in the air atmosphere for removing the template agent, exchanging the molecular sieve raw powder with ammonium ions, then roasting the molecular sieve raw powder at the high temperature to obtain a hydrogen type SSZ-13 molecular sieve with a high silicon-aluminum ratio (the ratio of nSiO2 to nAl2O3 is greater than 80), wherein the hydrogen type SSZ-13 molecular sieve has appropriate acidic sites, thermal stability and aperture size. According to the SSZ-13 molecular sieve with controllable and high silicon-aluminum ratio, high crystallinity, small crystal grains, the range of the silicon-aluminum ratio of SSZ-13 prepared by the conventional method is broken through; the problem that the crystallinity of the molecular sieve catalyst during regeneration is reduced can be solved; when the SSZ-13 molecular sieve is used as a catalyst and is applied to MTO reaction, the SSZ-13 molecular sieve has extremely high reaction activity and selectivity.

Description

technical field [0001] The invention relates to the synthesis of zeolite molecular sieves, in particular to a method for synthesizing SSZ-13 molecular sieve catalysts with small crystal grains and high silicon-aluminum ratio. Specifically, it is a method for synthesizing the SSZ-13 molecular sieve catalyst with small grain size and high silicon-aluminum ratio without using organic ammonium salt as a structure-directing agent. Background technique [0002] The American chemist Zones synthesized a new molecular sieve SSZ-13 molecular sieve by the hydrothermal method in the 1980s, which is classified according to the size of the zeolite channel and belongs to the small-pore zeolite in the micropore. The structure of molecular sieve SSZ-13 is composed of AlO4 and SiO4 tetrahedrons connected end to end through oxygen atoms, orderly arranged into a crystal structure with an eight-membered ring shape, the pore size is 0.38nm, and the pore area is 0.113nm 2 . This structural featu...

AI Technical Summary

Problems solved by technology

However, small crystal or nano zeolites still face many problems in the process of synthesis and use, for example, they are easy to agglomerate during synthesis, and the composition and reaction conditions of the synthesis system need to be strictly controlled

Agglomeration often occurs during post-treatment processes such as drying and high-temperature roasting, which usually reduces the use efficiency of nano-zeolites.

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