Hollow Cylindrical Shell Catalyst for Acrylic Acid Selectivity
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Solution Overview
Problem
Existing annular shell catalysts for the heterogeneously catalyzed partial gas phase oxidation of acrolein to acrylic acid face challenges in selectivity and activity, with a molar ratio of Cu to V being at least 0.8, which is not satisfactory for achieving optimal results.
Innovation Solution
Development of a shell catalyst with a hollow cylindrical support body coated with a catalytically active oxide material having the formula Mo12V2-4W0-3Cu0.8-1.5, where the stoichiometric coefficients of W, V, and Cu are adjusted to enhance volume-specific activity, and the catalyst is produced using specific methods involving calcination and application of the oxide mass to the support body.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the molar ratio of Cu to V is increased to at least 0.8 in existing shell catalysts, then the catalytic activity is maintained, but the selectivity of acrylic acid formation deteriorates and cannot be fully satisfactory
Solution Approach 1:
The invention changes the chemical composition parameters of the catalytically active oxide mass by introducing tungsten (W) with specific stoichiometric coefficients (0.1 to 3.0, preferably 0.5 to 2.0, particularly preferably 0.75 to 1.5) in addition to Mo, V, and Cu. This parameter modification resolves the contradiction by achieving both high selectivity (>95%) and high catalytic activity simultaneously, which was not possible with the conventional Cu/V ratio alone.
Solution Approach 2:
The invention creates a composite oxide material with the general formula Mo12V2-4W0-3Cu0.8-1.5O n, combining multiple metal oxides (molybdenum, vanadium, tungsten, copper) in specific ratios. This composite material approach allows the catalyst to achieve both high selectivity and high activity by synergistic interactions between the different metal components, resolving the limitation of using only Cu/V ratio control.
2Productivity
If the shell thickness of catalytically active oxide material is increased to improve activity, then the volume-specific activity increases, but the manufacturing precision and application complexity worsen
Solution Approach 1:
The invention optimizes the shell thickness parameter to specific ranges (10 to 1000 μm, preferably 10 to 500 μm, particularly preferably 100 to 500 μm, very particularly preferably 200 to 300 μm) to achieve the desired volume-specific activity while maintaining manufacturability. This parameter optimization resolves the contradiction by finding the optimal thickness range that balances catalytic performance with application feasibility.
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 catalysts exhibit improved selectivity and activity in the formation of acrylic acid, particularly at high acrolein loadings, with the optimal stoichiometric coefficients of W, V, and Cu contributing to increased volume-specific activity and selectivity.
Implementation Method 1
They are mainly used as catalysts for the heterogeneously catalyzed partial gas phase oxidation of acrolein to acrylic acid
Implementation Method 2
a shell made of catalytically active oxide material which is applied to the outer surface of the support body
Data Source
Figure 1
Figure 2
AI summary
The invention relates to a shell catalytic converter made of a hollow cylindrical carrier body having a length of 2 to 10 mm, an outer diameter of 4 to 10 mm, and a wall thickness of 1 to 4 mm, and shell made of a catalytically active oxide mass applied to the outer surface of the carrier body, said mass having the general formula (I): MO12V2 to 4W0 to 3CU0,8 to 1,5?1 0 to 4 X2 0 to 40On, where the variables having the following meanings: X1 = one or more elements of the alkali and alkali earth metals; X2 = one or more elements from group of Si, Al, Ti and Zr; and n = the stoichiometric coefficient of the element oxygen, which is determined by the stoichiometric coefficients of the elements other than oxygen and the charge numbers thereof in I.