Preparation method of copper-zinc catalyst

Abstract

The invention discloses a preparation method of a copper-zinc catalyst, wherein the preparation method includes the following contents: (1) dissolving Cu and Al soluble salts in water to prepare a solution A, and preparing a sodium carbonate solution B; (2) merging the solution A and the solution B and adding into a reaction tank, gelatinizing, then aging in a stirring condition, and adding nano zinc oxide in the gelatinizing and / or aging process; (3) filtering the slurry obtained in the step (2), and carrying out hydrothermal treatment on the obtained material with water steam, wherein urea is added during hydrothermal treatment; and (4) washing, filtering, drying, roasting and molding the material obtained in the step (3), and thus obtaining the copper-zinc catalyst. The copper-zinc catalyst prepared by the method has large active component copper oxide density in an epiphase, the utilization rate of active metal copper is high, the copper and zinc distribution is more uniform, the cooperation effect of the active metal copper and the auxiliary agent zinc is enhanced, a pore structure of the catalyst is reasonable, the activity, selectivity, heat stability of the catalyst for methanol synthesis are improved and the service life of the catalyst for methanol synthesis is prolonged.

Description

Technical field [0001] The invention relates to a method for preparing a copper-zinc catalyst, in particular to a method for preparing a copper-zinc catalyst with high activity, high selectivity and good heat resistance. Background technique [0002] Methanol is an extremely important chemical raw material, widely used in organic synthesis, dyes, fuels, medicine, coatings and national defense industries. Its output is second only to synthetic ammonia and ethylene, ranking third in the world. In recent years, methanol demand and production capacity have increased Industrial development continues to grow. [0003] Industrial methanol generally contains H 2 , CO, CO 2 The synthesis gas is produced under certain conditions of pressure, temperature and catalyst. At present, the medium and low pressure gas phase method is generally used to synthesize methanol in the world, and the catalyst used is basically a mixed oxide of copper, zinc and aluminum. CuO, ZnO, Al in methanol synthesis ...

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Problems solved by technology

[0010] The method for synthesizing methanol catalysts introduced in the above-mentioned patents is achieved by adding new additives (inorganic additives and organic additives), changing the catalyst preparation process (one-step process to two-step or three-step process) or changing the Al precursor. Increase the specific surface area of ​​the catalyst, change the grain size of CuO, adjust the proportion of catalyst components, and improve the dispersion of active components, so as to solve the problems of low activity and selectivity and short life of copper-based catalysts. There are disadvantages such as complex process, uneven dispersion of active components, small content of active metals in the surface phase of the catalyst, and low density of active centers.

[0011] Al 2 o 3 In the copper-based catalyst, it not only acts as a skeleton, but also can disperse the active components in the catalyst. How to use the additive Al 2 o 3 Skeletal effect, so that the main active component copper and promoter zinc appear more on the surface of the catalyst, increase the number of active centers on the catalyst surface, increase the contact probability of the active component copper and the promoter zinc, and make the catalyst have a suitable pore distribution , to significantly improve the activity, selectivity or lifetime of existing catalysts, which are not covered by the above patents

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