Metal Oxide Nano Zeolite Catalyst for Uniform Active Site Dispersion
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Solution Overview
Problem
Conventional methods for preparing hydrogenation catalytic conversion catalysts result in uneven dispersion of active sites, increased distances between metal and acid sites, and poor utilization of zeolites due to mechanical mixing, leading to weakened synergistic effects and increased production costs.
Innovation Solution
A method involving pretreatment of γ-Al2O3 balls with a quaternary ammonium alkali solution, followed by a hydrothermal synthesis of alumina-loaded zeolites, and a two-step high-temperature heat treatment to produce nano zeolite particles, which are then loaded with metal oxides, ensuring uniform distribution and improved catalytic performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If mechanical grinding mixture of zeolites and metal-loaded supports is used, then catalyst preparation is simple, but two active sites are unevenly dispersed and acid sites are far from metal sites
Solution Approach 1:
The patent embeds metal-loaded supports inside zeolite particles during hydrothermal synthesis, creating a nested structure where metal sites are enclosed within the zeolite matrix. This ensures intimate contact and uniform dispersion of both acid sites (on zeolite surface) and metal sites (inside particles), resolving the contradiction between simple preparation and uniform active site distribution.
Solution Approach 2:
The patent creates a composite catalyst structure combining zeolite and metal-loaded supports in a unified particle morphology. The composite structure allows both components to maintain their catalytic functions while achieving uniform spatial distribution, eliminating the need for separate mechanical mixing steps and ensuring optimal active site proximity.
2Quantity of substance
If conventional direct metal loading on zeolites is used, then metal sites are created, but large metal particles accumulate on zeolite surfaces due to incomplete filling
Solution Approach 1:
The patent loads metal compounds into the interior of zeolite particles during hydrothermal synthesis, creating a nested structure where metal sites are distributed throughout the particle volume rather than accumulating on the surface. This ensures complete filling of available sites and uniform metal distribution, preventing particle aggregation.
Solution Approach 2:
The patent utilizes the porous structure of zeolites to disperse metal compounds throughout the internal network. The porous framework provides extensive surface area and volume for metal loading, ensuring uniform distribution and preventing aggregation of large metal particles while maintaining high metal content.
3Adaptability or versatility
If zeolites are mixed with alumina by mechanical mixing, then HDT catalyst composition is achieved, but dispersibility of zeolites is poor and part of zeolites cannot act as catalyst
Solution Approach 1:
The patent embeds zeolite particles within alumina matrix during hydrothermal synthesis, creating a nested composite structure. This ensures uniform dispersion of zeolites throughout the alumina carrier, eliminating clumping and ensuring all zeolite particles are properly distributed and active, thus resolving the contradiction between achieving required composition and maintaining good dispersibility.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The method enhances the dispersibility and utilization of zeolites, reduces metal oxide agglomeration, and achieves a better synergistic effect between metal and acid sites, improving catalytic performance and reducing production costs.
Implementation Method 1
adding a quaternary ammonium alkali solution to wash industrial γ-Al2O3 balls, and then drying to obtain pretreated γ-Al2O3 balls
Implementation Method 2
hydrothermally crystallizing the mixture to generate an alumina loaded zeolite material
Implementation Method 3
calcining the alumina loaded zeolite material in a step S2 at a low temperature, then performing ammonium exchange, and then calcining at a high temperature to obtain an alumina loaded nano zeolite particle material
Implementation Method 4
performing ammonium exchange
Implementation Method 5
loading metal: preparing a salt solution containing Group VIB metals and/or Group VIII metals, adding the alumina loaded nano zeolite particle material prepared in a step S3, drying after impregnation
Data Source
AI summary
The present disclosure relates to a technical field of preparation of zeolite molecular sieve catalysts, and in particular relates to a preparation method of a metal oxide loaded nano zeolite particle catalyst. In the preparation method, industrial γ-alumina balls are treated with a quaternary ammonium alkali solution, then pretreated γ-alumina balls are mixed with a zeolite precursor solution and are hydrothermally crystallized. Then a two-step high-temperature heat treatment is performed to obtain an alumina loaded zeolite nano particle material, solving problems of large zeolite dosage and poor dispersion in hydrocracking catalysts. Finally, the metal oxide loaded nano zeolite particle catalyst is obtained by combining transition metals. Nano zeolite particles prepared regulate a surface acidity of alumina, and exfoliated zeolites may be used independently as a catalyst, which saves cost and improves a utilization of the zeolites.