Preparation method of ZnO-ZrO2@Al2O3@SAPO-34 dual-core-shell catalyst

Abstract

The invention discloses a preparation method of a ZnO-ZrO2@Al2O3@SAPO-34 dual-core-shell catalyst. The preparation method comprises the following steps: preparing ZnO-ZrO2@Al2O3 powder; taking Al2O3,P2O5, SiO2, MOR and H2O in a molar ratio of 1.0:0.8:0.6:2.5:80; adding pseudo-boehmite, ethyl orthosilicate and a template agent morpholine to an orthophosphoric acid solution sequentially while stirring, performing uniform stirring continuously, and performing stirring and aging for 24h at room temperature to form a sol system; adding 200-400-mesh ZnO-ZrO2@Al2O3 powder to the system according tothe core-shell mass ratio of ZnO-ZrO2@Al2O3: SAPO-34 of (1:4)-(4:1), performing uniform stirring continuously, and then, transferring the product into a reactor; and performing hydrothermal crystallization for 24-48h at 190-210 DEG C, performing cooling and filtration, performing washing to neutrality with deionized water, performing drying for 6h at 105 DEG C, and performing roasting for 3h at 500-600 DEG C to obtain the catalyst. The catalyst prepared by the preparation method disclosed by the invention can simultaneously improve the conversion rate of carbon dioxide and the selectivity of low-carbon olefin in a two-step process for preparing low-carbon olefin by CO2 hydrogenation through methanol.

Description

technical field [0001] The invention belongs to the technical field of chemical industry, in particular to a ZnO-ZrO 2 @Al 2 o 3 Preparation method of @SAPO-34 dual core-shell catalyst. Background technique [0002] Zinc Zirconium (ZnO-ZrO 2 ) The two-component catalyst is CO 2 Catalytic hydrogenation synthesis methanol process is a kind of metal oxide catalyst with strong anti-sintering stability and anti-sulfur ability and good effect. SAPO-34 molecular sieve is made of SiO 4 , AlO 4 and PO 4 Microporous silicoaluminophosphate-based molecular sieves with three kinds of tetrahedral units interlaced to form a three-dimensional intersecting channel structure are widely used in Methanol catalytic cracking to light olefins process (MTO). Accordingly, a bifunctional core-shell catalyst was prepared by coupling metal oxides and acidic molecular sieves, and applied to CO 2 In the hydrogenation process of methanol to light olefins, it is CO 2 The design and development...

AI Technical Summary

Problems solved by technology

However, the active components of existing composite catalysts are randomly distributed, and the structure only provides an open reaction environment. More importantly, the distribution structure with traditional nano-copper particles as the active component has extremely poor anti-sintering stability and cannot effectively solve the problem of CO 2 CO in the two-step process of hydrogenation and methanol to light olefins 2 The hydrogenation synthesis of methanol process and methanol catalytic conversion to light olefins process require different reaction formation and dissociation conversion environmental conditions, resulting in the poor catalytic effect of existing composite catalysts