Okra type SAPO-34 molecular sieve as well as preparation method and application thereof

Abstract

The invention discloses an okra type SAPO-34 molecular sieve as well as a preparation method and application thereof. The preparation process mainly comprises the following steps: mixing a phosphorus source, a silicon source, an aluminum source, a template agent and deionized water, and heating and stirring to obtain a synthetic solution A; adding powder polyvinyl alcohol and hydrofluoric acid into the synthetic solution A, and continuously heating and stirring to obtain a dispersed synthetic solution B; and transferring the dispersed synthetic solution B into a high-pressure reaction kettle, carrying out hydrothermal crystallization, and filtering, washing, drying, roasting and cooling the obtained solid product. The prepared SAPO-34 molecular sieve is of a special okra type morphology structure, the particle size length is 3-5 microns, the particle size width is 0.5-1.5 microns, the SAPO-34 molecular sieve is an excellent catalyst carrier due to the special morphology, mass transfer is facilitated due to the flat structure, and the SAPO-34 molecular sieve shows excellent catalytic performance in the methanol-to-olefin catalytic reaction process.

Description

technical field [0001] The invention belongs to the technical field of molecular sieve materials, and in particular relates to an okra-type SAPO-34 molecular sieve and a preparation method and application thereof. Background technique [0002] Due to its special pore structure, SAPO-34 molecular sieve has good shape selectivity to ethylene, propylene and other low-carbon olefins, and as the main catalyst, it shows excellent catalytic activity in methanol to olefins. However, the smaller pores and the conventional cubic shape limit the mass transfer to a certain extent. Studies have shown that the sheet-like shape or flat shape can shorten the diffusion path of reactants and products, inhibit the formation of carbon deposits and prolong the Catalyst service life. [0003] The invention patent of 201610915336.X introduced a preparation method of layered SAPO-34 molecular sieve. The templating agent used in this patent is tetraethylammonium hydroxide, which is used in a relat...

AI Technical Summary

Problems solved by technology

The molecular sieve prepared by this patent has a small needle-like shape and a short crystal width, which is conducive to shortening the mass transfer distance, but due to its fine size, its mechanical stability may be poor

[0005] In summary, SAPO-34 molecular sieve catalysts with conventional cubic morphology have the problem of long mass transfer diffusion distance, and the lamellar and needle-like morphology have poor mechanical resistance.

Images