Copper Catalyst Bodies Volume Shrinkage Reduction
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Solution Overview
Problem
Copper-containing catalysts experience significant volume shrinkage and loss of mechanical strength during reduction, leading to inefficient reactor utilization and stability issues, particularly in methanol synthesis and CO conversion processes.
Innovation Solution
A process involving the combination of alkaline and copper-containing solutions to form a precipitate, followed by thermal treatment and tableting, which results in shaped catalyst bodies with reduced volume shrinkage and enhanced mechanical strength, using a specific ratio of mixed oxides and catalyst precursors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If copper-containing catalysts are produced using conventional multi-stage process with thermal treatment and tableting, then the catalysts achieve the required catalytic activity, but they undergo pronounced volume shrinkage during reduction which leads to significant loss of mechanical strength
Solution Approach 1:
The invention applies preliminary action by performing a specific thermal treatment (calcination) of the catalyst precursor at 200-600°C before tableting to form a mixed oxide with controlled pore structure and surface area (80-140 m²/g). This preliminary structural preparation ensures that when the catalyst is later reduced in situ, the mechanical strength is preserved despite the phase transformation, thereby resolving the contradiction between achieving catalytic activity and maintaining mechanical strength.
Solution Approach 2:
The invention utilizes parameter changes by controlling the thermal treatment temperature (200-600°C) and duration to optimize the pore structure and surface area of the mixed oxide precursor. By adjusting these parameters, the catalyst precursor develops an optimal structure that minimizes volume shrinkage during subsequent reduction, thus maintaining mechanical strength while ensuring catalytic activity is achieved.
2Ease of operation
If copper-containing catalysts are reduced before reactor loading to improve mechanical strength, then the catalysts are easier to handle, but they reoxidize over time through contact with air and require additional stabilization steps
Solution Approach 1:
The invention applies inversion by reversing the conventional sequence: instead of reducing the catalyst before loading (which improves handling but compromises stability), the catalyst is loaded in its stable oxide form and then reduced in situ during the first reaction cycle. This inverted approach eliminates storage stability issues while still achieving the required mechanical properties through the controlled thermal treatment of the precursor.
Solution Approach 2:
The invention employs self-service by enabling the catalyst to be activated (reduced) automatically during its first operational cycle in the reactor. The reduction occurs in situ using the reaction environment itself, eliminating the need for separate stabilization steps or external reducing agents, thereby simplifying the overall process while maintaining storage stability.
3Stability of the object's composition
If the catalyst bed undergoes volume shrinkage during operation, then the catalyst structure becomes more dense, but the reactor utilization decreases and heat exchange surface utilization is reduced
Solution Approach 1:
The invention applies preliminary action by pre-forming the catalyst precursor with an optimized pore structure and surface area through controlled thermal treatment before tableting. This preliminary structuring creates a robust framework that resists excessive shrinkage during reduction and operation, thereby maintaining reactor utilization and heat exchange surface efficiency while achieving the necessary structural density for stability.
Solution Approach 2:
The invention utilizes composite materials by creating a mixed oxide precursor containing copper, zinc, and aluminum oxides with specific surface areas (80-140 m²/g). This composite structure provides both the necessary density for stability and sufficient porosity to minimize shrinkage, thereby resolving the contradiction between structural density and reactor utilization.
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 achieves catalyst bodies with minimal volume shrinkage and high mechanical strength, improving reactor efficiency and stability, specifically suitable for methanol synthesis and low-temperature CO conversion.
Implementation Method 1
combining an alkaline solution, in particular a carbonate-containing precipitant, with a copper-containing solution obtainable by dissolving and/or suspending a copper compound
Implementation Method 2
the material is dried to form a solid catalyst precursor. In a further step, this solid catalyst precursor is thermally treated and converted into a largely oxide state
Implementation Method 3
The catalyst mass is then shaped by tableting, granulation, extrusion, or a combination of these methods. Finally, the resulting shaped body is converted into the catalytically active, highly dispersed copper metal using hydrogen, carbon monoxide or wet chemical reducing agents
Data Source
AI summary
The invention relates to a method for producing catalysts containing copper, in particular for producing catalyst moldings having increased mechanical strength and low volume reduction, to the catalysts produced by means of the method according to the invention, and to the use of said catalysts as catalysts or as precursors and components for catalysts. The catalysts according to the invention are suitable in particular for the synthesis of methanol and for the low-temperature conversion of CO into CO2.