Superabsorbent Particle Drying and Recycling Process
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Solution Overview
Problem
The production of superabsorbent particles faces challenges in efficiently processing incompletely dried polymer particles, which affects the quality and efficiency of the final product, as existing methods do not effectively balance moisture content and particle size for optimal processing.
Innovation Solution
A process involving the classification of dried polymer gel into fractions of incompletely and completely dried particles, followed by comminution and recycling of incompletely dried particles, with storage to balance moisture content, allowing further processing without additional drying, and subsequent thermal surface postcrosslinking for improved properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If incompletely dried polymer particles are removed and recycled into the drying operation, then processing efficiency is improved, but the moisture content balance and particle size optimization are compromised
Solution Approach 1:
The patent segments the polymer particles into different fractions based on moisture content and particle size during the drying process. Incompletely dried particles are separated from completely dried particles, allowing each fraction to be processed differently - the incompletely dried particles are comminuted and recycled, while completely dried particles proceed to surface postcrosslinking. This segmentation enables simultaneous optimization of processing efficiency and moisture content balance.
Solution Approach 2:
The patent applies preliminary comminution to incompletely dried polymer particles before recycling them back into the drying operation. This preliminary action reduces the particle size of incompletely dried particles, making them more suitable for recycling and ensuring they will be properly processed in subsequent drying cycles, thereby maintaining moisture content balance while improving processing efficiency.
2Manufacturing precision
If incompletely dried polymer particles are comminuted and recycled, then particle size optimization is improved, but additional drying time is required
Solution Approach 1:
The patent implements a continuous recycling loop where incompletely dried polymer particles are comminuted and returned to the drying operation. This continuous cycle ensures that particle size optimization is achieved through repeated comminution and drying cycles, with the system operating continuously to minimize overall processing time while maintaining optimal particle size distribution.
Solution Approach 2:
The patent changes the physical parameters of incompletely dried polymer particles by applying comminution to reduce particle size before recycling. This parameter change (particle size reduction) allows the particles to be more effectively processed in subsequent drying cycles, optimizing final particle size while the recycling mechanism minimizes additional drying time required.
3Reliability
If surface postcrosslinking is performed on dried polymer particles, then absorption properties are improved, but processing complexity increases
Solution Approach 1:
The patent applies surface postcrosslinking selectively only to completely dried polymer particles that have passed through the classification process, while leaving incompletely dried particles for separate processing. This local application of surface postcrosslinking ensures optimal absorption properties are achieved on the appropriate particle fraction, while the classification system manages the complexity by separating the processing streams.
4Manufacturing precision
If classification is performed to separate incompletely and completely dried particles, then moisture content balance is improved, but device complexity increases
Solution Approach 1:
The patent employs a classification system that segments polymer particles into incompletely dried and completely dried fractions based on moisture content. This segmentation is achieved through mechanisms such as centrifugal separation or sieve analysis, which divide the particle stream into distinct moisture-based fractions, enabling subsequent differential processing while maintaining moisture content balance.
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 enables the production of superabsorbent particles with balanced moisture content and optimized particle size, enhancing processing efficiency and product quality by integrating comminution and storage steps to manage moisture and size effectively.
Implementation Method 1
drying a polymer gel to produce a dried polymer gel
Implementation Method 2
storing them together with the dried polymer gel before step ii) or the dried polymer particles after step ii) in a vessel for a period of at least 5 minutes... the combined storage of the comminuted incompletely dried polymer particles and of polymer particles having a low moisture content leads to balancing of the moisture content
Implementation Method 3
Crosslinkers suitable for that purpose are compounds which can form covalent bonds with at least two carboxylate groups of the polymer particles
Data Source
AI summary
A process for producing superabsorbent particles, comprising drying of a polymer gel, removal of incompletely dried polymer particles, comminution of the polymer particles removed, recycling of the comminuted polymer particles and storage of the recycled polymer particles.