Cu/ZnO/Alumina-Silica Catalyst Composition for Stable CO Conversion
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Solution Overview
Problem
Existing copper-based catalysts for carbon oxide conversion reactions, such as the water-gas shift reaction and methanol synthesis, suffer from low initial activity and poor stability due to the use of silica derived from soluble aluminum salts or the absence of silica, leading to reduced selectivity and longevity.
Innovation Solution
A catalyst composition comprising copper oxide, zinc oxide, alumina, and silica, where the alumina is derived from an alumina sol, with a specific Si:Al atomic ratio and high copper surface area, is prepared by co-precipitation and calcination, followed by shaping into pellets, enhancing initial activity and resistance to deactivation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If silica is derived from soluble aluminum salts or is absent, then manufacturing is simpler, but initial activity and stability deteriorate
Solution Approach 1:
The patent changes the source material parameter from soluble aluminum salts to alumina sol, and controls the Si:Al atomic ratio parameter within 0.005-0.15:1. This parameter change transforms the silica derivation approach while maintaining manufacturing feasibility, resolving the contradiction between ease of manufacture and catalyst reliability
Solution Approach 2:
The patent creates a composite catalyst system combining copper oxide, zinc oxide, alumina, and silica in specific proportions. The alumina-silica composite structure provides both mechanical stability and high initial activity, while the specific Si:Al ratio optimization ensures manufacturing feasibility. This composite approach resolves the contradiction by integrating multiple materials with complementary functions
2Productivity
If copper oxide is reduced to metallic copper to increase surface area, then initial activity improves, but resistance to deactivation deteriorates
Solution Approach 1:
The patent optimizes the copper surface area parameter to greater than 37m²/g catalyst through controlled reduction, while simultaneously optimizing the alumina-silica support structure and Cu:Zn:Al:Si molar ratios. These parameter changes enable high initial activity while the stabilized support structure enhances resistance to deactivation
Solution Approach 2:
The patent uses a composite structure where metallic copper particles are dispersed on an alumina-silica support. The alumina derived from alumina sol provides structural stability that prevents copper sintering and deactivation, while the high copper surface area maintains high initial activity. This composite architecture resolves the contradiction between productivity and reliability
3Ease of manufacture
If alumina is derived from soluble aluminum salts, then manufacturing is easier, but resistance to deactivation deteriorates
Solution Approach 1:
The patent changes the alumina source parameter from soluble aluminum salts to alumina sol, and controls the Si:Al atomic ratio within 0.005-0.15:1. This parameter change maintains manufacturing ease while dramatically improving resistance to deactivation, as the alumina sol provides a more stable alumina structure
Solution Approach 2:
The patent uses alumina sol as an intermediary material that bridges the gap between ease of manufacture and high reliability. The alumina sol can be easily processed into the catalyst structure while providing superior structural stability and resistance to deactivation compared to alumina from soluble salts
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 catalyst exhibits high initial activity and improved resistance to deactivation, maintaining performance over time, particularly suitable for methanol synthesis and water-gas shift reactions.
Implementation Method 1
The intimate mixture is generally made by precipitation of copper compounds and compounds convertible to the other oxidic materials, and/or precipitation of the copper compounds in the presence of the other oxidic materials or compounds convertible thereto
Implementation Method 2
followed by calcination to convert the precipitated copper compounds, and other components as necessary, to the oxides
Implementation Method 3
the pellets are subjected to reducing conditions to reduce the copper oxide in said pellets to metallic copper
Data Source
AI summary
A catalyst suitable for use in carbon oxide conversion reactions is described, said catalyst in the form of a shaped unit formed from an oxidic catalyst powder, said catalyst comprising 30-70% by weight of copper oxide, combined with zinc oxide, alumina and silica, having a Si:Al atomic ratio in the range 0.005 to 0.15:1, and having a BET surface area ≥105 m2/g and a copper surface area >37 m2/g catalyst. The catalyst is prepared by a co-precipitation method using an alumina sol.