Graphite Shaping Aid for Multi-Element Oxide Catalysts
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Solution Overview
Problem
Existing methods for producing shaped catalyst bodies with multi-element oxides do not adequately consider the properties of graphite as a shaping aid, particularly its grain size and specific surface area, which affects the catalytic performance in heterogeneously catalyzed partial gas phase oxidations of organic compounds.
Innovation Solution
A process for producing shaped catalyst bodies with a finely divided precursor mixture containing graphite as a shaping aid, where the graphite has a specific surface area between 0.5 and 5 m^2/g and a particle diameter between 90 μm and 200 μm, and is thermally treated to form a multi-element oxide catalyst with improved selectivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If graphite with small particle diameter and large specific surface area is used as shaping aid, then the catalyst has high activity, but the selectivity to target product decreases due to complete oxidation
Solution Approach 1:
The patent changes the physical parameters of graphite (particle diameter and specific surface area) to resolve the contradiction. By selecting graphite with particle diameter of 3-10 μm and specific surface area of 1-5 m²/g, the patent achieves optimal balance between catalytic activity and selectivity, preventing complete oxidation while maintaining high activity.
Solution Approach 2:
The patent applies local quality by optimizing the distribution and properties of graphite within the catalyst structure. The controlled particle size and surface area of graphite create specific local environments that favor partial oxidation reactions over complete oxidation, thereby improving selectivity to target products.
2Shape
If graphite is added as shaping aid, then the catalyst structure is improved, but the combustion temperature must be carefully controlled to avoid affecting catalytic performance
Solution Approach 1:
The patent controls the combustion temperature parameter during catalyst preparation. By maintaining the combustion temperature below 700°C (preferably 400-650°C), the patent achieves proper catalyst structure formation while preventing excessive graphite combustion that would degrade catalytic performance.
3Adaptability or versatility
If multi-element oxides are used as active material, then the catalyst is suitable for partial oxidations, but the production process requires precise control of graphite properties
Solution Approach 1:
The patent establishes specific parameter ranges for graphite (particle diameter: 3-10 μm, specific surface area: 1-5 m²/g) that simplify the production process. By defining these clear parameter specifications, the patent makes the process controllable and reproducible while maintaining the catalyst's versatility for various partial oxidation reactions.
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 process results in catalysts with enhanced target product selectivities in heterogeneously catalyzed partial gas phase oxidations by optimizing the graphite's properties, leading to improved catalytic performance.
Implementation Method 1
the resulting shaped catalyst precursor bodies are thermally treated at elevated temperature to obtain the shaped catalyst bodies, the active material of which is a multi-element oxide
Implementation Method 2
at least 1% by weight, preferably at least 2% by weight, particularly preferably at least 3% by weight, and very particularly preferably at least 5% by weight, of the amount of graphite contained in the shaped catalyst precursor bodies (calculated as the pure amount of carbon) is converted into gaseous escaping compounds (e.g. to CO and/or CO2 burned)
Data Source
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AI summary
The invention relates to a method for producing catalyst moulded bodies whose active mass is a multi-element oxide, wherein a finely-divided precursor mixture is moulded to the desired geometry by adding a graphite having a specific particle size, and is subsequently thermally treated.