A monolithic honeycomb structure forming method for molecular sieve catalyst

Abstract

The invention provides a forming method of an integral cellular molecular sieve based catalyst. The forming method comprises the following steps: (1) impregnating a molecular sieve in a metal solution, and performing stirring, drying and high-temperature calcining to prepare a powdery molecular sieve based catalyst; (2) adding an adhesive, an extrusion aid, an acid solution and water, and mixing and kneading to obtain a wet material paste; (3) performing primary smelting, vacuum refining and high-pressure vacuum extrusion on the wet material paste to extrude to form a cellular integral wet-based blank body; (4) preparing the cellular integral molecular sieve based catalyst from the blank body by drying, cutting, polishing and calcining for 6-10 h at 500-550 DEG C. The forming method can precisely control key parameters in the drying process and limit the water loss rate of the blank body, and ensures that the blank body is high in strength and neat and orderly in shape. The forming method can be applied to industrial mass production, and adopts equipment in the prior art to reasonably arrange the process route so as to obtain qualified industrial application products.

Description

technical field [0001] The invention belongs to the technical field of catalysis, and in particular relates to a method for forming an integral honeycomb structure of a molecular sieve catalyst. Background technique [0002] Molecular sieves are widely used in many fields, such as microporous molecular sieves, as the main catalytic materials, adsorption separation materials and ion exchange materials, play an increasingly important role in petroleum processing, petrochemical, fine chemical, daily chemical and environmental protection fields. role. The application forms of molecular sieve catalysts are usually powder and granular, and granular catalysts can be divided into spherical, strip and clover, etc. These types of monolithic catalysts are widely used because of their simple preparation and mature industrial routes. [0003] With the intensification of environmental pollution, industrial waste gas is in urgent need of deep treatment, and molecular sieves have been used...

AI Technical Summary

Problems solved by technology

The monolithic molecular sieve catalyst prepared by the coating method, although the active components can be evenly distributed by certain techniques, can not solve the shortcomings of less active components, different thermal expansion coefficients between the carrier and the molecular sieve, which cause the molecular sieve to fall off, and the activity is easy to lose.

The in-situ generation method is to use the formed monolithic honeycomb structure to generate new molecular sieves on its surface through hydrothermal synthesis to prepare a honeycomb monolithic molecular sieve catalyst. Synthetic molecular sieves for N 2 Catalytic direct decomposition of O, the molecular sieve mass is 5% to 30% of the mass of the monolithic catalyst. This method also faces the problem of molecular sieve catalyst falling off after a period of use. At the same time, the preparation process of this method is complicated, which is not conducive to industrial production.

[0006] And patent CN103111322A has reported a kind of N 2 The preparation method of the monolithic honeycomb molecular sieve catalyst for O decomposition, the method is to directly form the active components, binders, extrusion aids, etc. through pressurization, and prepare the monolithic honeycomb molecular sieve catalyst, but this method is limited to the experiment chamber, the size of the preparation is small, and a complete process route has not been formed in the industry, the problem of engineering scale-up needs to be solved, and the application field is narrow

[0007] Molecular sieve is a porous material with a high temperature sensitivity index and is easy to crack during the drying process. Therefore, its molding preparation is a technical bottleneck, which directly affects the industrial application of molecular sieve catalysts.

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