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. The preparation method comprises the following steps: 1, modifying to prepare an Ag / SAPO-34 molecular sieve: uniformly mixing a silver nitrate solution with an SAPO-34 molecular sieve according to the load capacity of 1-10wt% through adopting an isometric impregnation technique, impregnating the molecular sieve at normal temperature for 10h, drying the obtained molecular sieve at 85DEG C until the weight is constant, roasting the dried molecular sieve at 550DEG C for 5h, and cooling the roasted molecular sieve to room temperature; and 2, modifying to prepare an I-Ag / SAPO-34 molecular sieve: uniformly mixing an iodine-containing substance solution with the Ag / SAPO-34 molecular sieve prepared in step 1 according to the load capacity of 1-10wt% through adopting the isometric impregnation technique, carrying out ultrasonic impregnation at normal temperature for 10-30min, routinely impregnating the molecular sieve for 2-12h, and drying the obtained molecular sieve at 50-105DEG C until the weight is constant. The modified SAPO-34 molecular sieve catalyst prepared in the invention can improve the methanol low-temperature conversion rate and the low-carbon olefin selectivity, and has a long service life.

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.