A kind of preparation method of modified sapo-34 molecular sieve catalyst

Abstract

The invention discloses a preparation method of a modified SAPO-34 molecular sieve catalyst, comprising the following steps: (1), preparing Cu / SAPO-34 molecular sieve by modifying: mixing well copper nitrate solution and SAPO-34 molecular sieve according to a copper loading capacity of 1-12wt.% by means of isometric impregnation, impregnating at normal temperature for 2-12 h, drying at 50-120 DEG C to constant weight, calcining at 550 DEG C for 2 h, reductively calcining in hydrogen atmosphere at 200-400 DEG C for 2-6 h, and cooling to room temperature; (2), preparing I-Cu / SAPO-34 molecular sieve by modifying: mixing well iodine species-containing solution and the Cu / SAPO-34 molecular sieve prepared in step (1) according to a loading capacity of 1-12wt.% by means of isometric impregnation, ultrasonically impregnating at normal temperature for 10-20 min and then impregnating conventionally for 2-12 h, and drying at 50-105 DEG C to constant weight. Methanol low-temperature conversion rate and low-carbon olefin selectivity can be improved, and the service life of the catalyst is long.

Description

technical field [0001] The invention belongs to the technical field of chemical industry, and in particular relates to a preparation method of a modified SAPO-34 molecular sieve catalyst. Background technique [0002] SAPO-34 molecular sieve is made of SiO 4 , AlO 4 、PO 4 The chabazite-type microporous molecular sieve is composed of three tetrahedral units and has an elliptical cage and a three-dimensional intersecting channel structure. Because of its good hydrothermal stability, large specific surface area and strong shape-selective catalytic function, especially the unique cage structure shows high selectivity of low-carbon olefins, it has been widely used in the production of low-carbon olefins from coal-based methanol Olefin (MTO) technology process. [0003] Due to the small pores of the SAPO-34 molecular sieve and the unique cage structure, it is easy to form a large amount of carbon deposits, resulting in rapid deactivation and short life of the catalyst. At pre...

AI Technical Summary

Problems solved by technology

Therefore, a higher reaction temperature not only increases the unit energy consumption of the product, but also accelerates the formation of carbon deposits, resulting in rapid deactivation of the catalyst and the need for frequent regeneration, further increasing the production cost of the product

It can be seen that the existing MTO process has shortcomings such as high reaction temperature, high energy consumption per unit of product, easy carbon deposition and deactivation of the catalyst, and frequent regeneration.