Water-absorbing polymer drying process with vibrating screen

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Solution Overview

Problem

The production of water-absorbing polymer particles often results in inhomogeneous drying, leading to incompletely dried polymeric particles that cause quality issues and require separation, which is inefficient and labor-intensive.

Innovation Solution

A process involving polymerization of a monomer solution with ethylenically unsaturated monomers, crosslinkers, and initiators, followed by drying on a through-circulation belt dryer, crushing, pre-grinding, and separation using a vibrating perforated screen to effectively remove incompletely dried particles, with subsequent grinding and classification to achieve uniform particle size.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If drying is performed on a through circulation belt dryer, then drying efficiency is improved, but inhomogeneous drying occurs leading to incompletely dried particles

Engineering Contradiction:
Improvedrying efficiencyVSAvoiddrying uniformity
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

Oversize lumps are removed before drying to prevent them from causing inhomogeneous drying. By performing this preliminary size reduction, the drying process can proceed uniformly across all particles, eliminating the need for over-drying certain areas to compensate for under-dried lumps.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The drying process is made dynamic through continuous size reduction during drying. The system transitions from static drying to dynamic processing where particles are continuously crushed and redistributed, allowing uniform moisture removal throughout the drying period.

Inventive Principle:
Principle #15Dynamics

2Manufacturing precision

If oversize lumps are removed before drying, then drying uniformity is improved, but additional processing steps are required

Engineering Contradiction:
Improvedrying uniformityVSAvoidprocessing steps
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

Multiple functions are merged into a single continuous process. Size reduction, drying, and further size reduction are combined into one integrated flow where particles move through the system continuously, being crushed at multiple stages without discrete separation between operations.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The process maintains continuous useful action by eliminating idle time between operations. Particles are continuously fed through drying and crushing operations without interruption, and the crushed material is immediately redistributed for further drying, maximizing process efficiency.

Inventive Principle:
Principle #20Continuity of useful action

3Manufacturing precision

If incompletely dried particles are separated and recycled, then product quality is improved, but maintenance routine work increases

Engineering Contradiction:
Improveproduct qualityVSAvoidmaintenance work
Core Design Contradiction:
Manufacturing precisionVSEase of manufacture

Solution Approach 1:

Size reduction is performed preliminarily before drying to prevent lump formation that would cause incomplete drying. This preliminary crushing eliminates the root cause of the problem, reducing the need for subsequent separation and recycling operations.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The problematic oversize lumps are extracted and removed from the process flow before they can cause drying issues. By taking out these problematic particles early, the system avoids the cycle of incomplete drying, separation, and recycling that increases maintenance work.

Inventive Principle:
Principle #2Taking out (Extraction)

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 process significantly reduces the amount of incompletely dried particles, improves the service life of the vibrating screen, and results in polymer particles with consistent moisture content and particle size distribution, enhancing product quality and reducing maintenance.

Implementation Method 1

separating of incompletely dried particles with a vibrating screen

Methodology Applied
Scientific EffectVibration: Vibration

Implementation Method 2

a perforated plate having a thickness from 0.5 to 5mm, an opening area from 20 to 80% and a hole diameter from 5 to 20mm

Methodology Applied
Scientific EffectFiltration: Filter (physical)

Implementation Method 3

drying the resulting polymer gel on a through circulation belt dryer

Methodology Applied
Scientific EffectEvaporation: Evaporation

Implementation Method 4

drying the resulting polymer gel on a through circulation belt dryer

Methodology Applied
Scientific EffectHeat transfer: Conduction (thermal)

Data Source

PatentEP2890722B1Process for producing water-absorbing polymer particles
Publication Date: 2018.11.21 BASF SE
  • EP2890722B1 patent drawingFigure 1

AI summary

The invention relates to a process for producing water-absorbing polymer particles, comprising polymerization, drying the resulting polymer gel on a through circulation belt dryer, crushing the dried polymer gel, pre-grinding, separating of incompletely dried particles with a perforated plate, grinding and classifying the resulting polymer particles.