Air-Permeable Conveyor Belt for Uniform Catalyst Drying
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Solution Overview
Problem
The production of multimetal oxide catalysts for propene oxidation to acrolein or acrylic acid often results in non-uniform catalyst characteristics due to uneven drying of extrudates, leading to suboptimal yield, selectivity, and catalyst life in industrial reactors.
Innovation Solution
A method involving the preparation of a plasticized precursor composition, extrusion into strands, breaking into pieces, and drying on an air-permeable conveyor belt under reduced pressure to ensure uniform drying and prevent sticking, resulting in a catalyst with improved uniformity and performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If extrudates are dried on a conventional conveyor belt, then drying efficiency is improved, but extrudates stick together and intertwine causing non-uniform drying
Solution Approach 1:
The conveyor belt is designed with air-permeable properties, allowing air to pass through from both above and below the extrudates. This porous structure enables uniform drying by eliminating sticking and intertwining, while maintaining high drying efficiency through enhanced air circulation.
Solution Approach 2:
The drying system uses air flow through the porous conveyor belt from both sides to achieve uniform moisture removal. The pneumatic approach allows simultaneous drying of both surfaces of each extrudate, improving efficiency while preventing sticking through controlled air circulation.
2Productivity
If extrudates are dried at high temperature to improve drying speed, then productivity increases, but extrudates stick together causing non-uniform characteristics
Solution Approach 1:
The system uses air flow through the porous belt from both sides to achieve efficient drying without excessive temperature. The pneumatic drying approach removes moisture through air circulation rather than relying solely on high heat, preventing sticking while maintaining drying speed.
Solution Approach 2:
The porous conveyor belt structure allows distributed air flow through and around the extrudates, enabling efficient heat and mass transfer at moderate temperatures. This prevents localized overheating and sticking while maintaining overall drying efficiency.
3Manufacturing precision
If all precursor material is treated under uniform conditions to obtain uniform active material, then catalyst performance is improved, but process complexity increases
Solution Approach 1:
The porous conveyor belt provides a simple structural solution that achieves uniform drying conditions across all extrudates. The air-permeable design naturally distributes air flow uniformly, eliminating the need for complex control systems while ensuring consistent catalyst characteristics.
Solution Approach 2:
The porous conveyor belt serves multiple functions simultaneously: it supports the extrudates, allows air flow from both sides for uniform drying, and prevents sticking through its permeable structure. This multi-functionality simplifies the overall drying system while achieving uniform catalyst production.
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
This approach produces catalysts with enhanced product selectivity and COx-selectivity by maintaining uniform characteristics and preventing extrudate sticking, thereby optimizing catalyst performance and reactor efficiency.
Implementation Method 1
moving the pieces through the at least one drying chamber on an air permeable drying conveyor belt
Implementation Method 2
steps b) through d), preferably steps b) through e), are carried out under reduced pressure
Data Source
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AI summary
A method for producing a multimetal oxide catalyst comprises preparation of a precursor composition, exposing said precursor composition to elevated temperatures to activate the composition, and grinding the activated composition. The preparation of the precursor composition comprises: a) forming a plasticized precursor composition from the constituents of the composition; b) discharging the plasticized precursor composition from an extruder having at least one die to form extrudates; c) allowing the extrudates to drop onto a transfer surface disposed beneath the at least one die whereby the extrudates break into pieces which come to rest on the transfer surface; d) transferring the pieces to at least one drying chamber; and e) moving the pieces, through the at least one drying chamber on an air permeable drying conveyor belt; wherein steps b) through d) are carried out under reduced pressure. The method allows the production of a multimetal oxide catalyst with uniform characteristics. Fine particles of the multimetal oxide precursor that may be generated during extrusion of the plasticized precursor composition and handling of the extrudates are removed.