Separating Plastic and Cellulose from Sanitary Products

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Solution Overview

Problem

Existing methods for recycling post-consumer absorbent sanitary products are inefficient due to the presence of organic excretions and high humidity, which complicates the separation of plastic and cellulose, requiring additional sterilization steps and different apparatuses for post-production versus post-consumer products.

Innovation Solution

A method involving a rotary autoclave for sterilization, followed by shredding and drying, and then using centrifugal separators to efficiently separate plastic and cellulose, with a system that includes a conveyor belt and multiple stages of centrifugal separation to achieve high purity of both materials.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If washing methods are used to separate plastic and cellulose from post-consumer absorbent sanitary products, then separation can be achieved, but the process becomes inefficient and requires additional sterilization steps due to organic excretions and high humidity

Engineering Contradiction:
Improveseparation efficiencyVSAvoidprocess complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent applies preliminary sterilization and drying actions before the separation process. The rotary autoclave performs sterilization and moisture removal in advance, preparing the material for more efficient mechanical separation in the centrifugal separator, thereby avoiding complications from organic excretions and high humidity during separation

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent divides the recycling process into distinct sequential stages: sterilization, drying, shredding, and separation. Each stage is handled by dedicated equipment (rotary autoclave, shredder, centrifugal separator), allowing each process to be optimized independently and improving overall separation efficiency without increasing unnecessary complexity

Inventive Principle:
Principle #1Segmentation

2Reliability

If different apparatuses are used for post-production versus post-consumer products, then specific requirements are met, but operational complexity increases

Engineering Contradiction:
Improveproduct treatment effectivenessVSAvoidoperational complexity
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The patent employs a multi-functional rotary autoclave that can process both post-production and post-consumer absorbent sanitary products. The autoclave's sterilization and drying functions address the specific requirements of post-consumer products (organic excretions, high humidity) while maintaining effectiveness for post-production materials, thereby reducing the need for separate dedicated apparatuses and simplifying operations

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Reliability

If sterilization steps are added for post-consumer products, then bacteria are eliminated, but processing time and operational complexity increase

Engineering Contradiction:
Improvesterilization effectivenessVSAvoidprocessing time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent merges sterilization and drying functions into a single rotary autoclave unit. This combination eliminates the need for separate sterilization and drying steps, reducing total processing time while maintaining sterilization effectiveness. The integrated design also simplifies operations by using one apparatus instead of multiple sequential equipment

Inventive Principle:
Principle #5Merging (Combining)

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 method achieves efficient sterilization, shredding, and separation of plastic and cellulose from post-consumer absorbent sanitary products, resulting in high purity outputs with continuous processing and reduced operational complexity.

Implementation Method 1

The autoclave is loaded with post-consumer absorbent sanitary products without prior shredding of the products. The autoclave containing a load of sterilized products is closed and heated to a sterilization temperature

Methodology Applied
Scientific EffectHeating: Heating

Implementation Method 2

centrifugal separation of plastic and cellulose from the shredded material. Centrifugal separators used for separating plastic and cellulose comprise a perforated drum and a rotor rotating inside the perforated drum, which projects the shredded mass radially outwards

Methodology Applied
Scientific EffectCentrifugal separation: Centrifugal Separation

Data Source

PatentEP3518987B1A method and apparatus for separating plastic and cellulose from post-consumer absorbent sanitary products
Publication Date: 2023.07.19 PROCTER & GAMBLE CO
  • EP3518987B1 patent drawingFigure 1
  • EP3518987B1 patent drawingFigure 2~3
  • EP3518987B1 patent drawingFigure 4

AI summary

A method for separating plastic and cellulose from post-consumer absorbent sanitary products, comprising: - sterilizing successive batches of post-consumer absorbent sanitary products in at least one rotary autoclave (18), - shredding the sterilized absorbent sanitary products and obtaining sterilized and shredded material containing plastic and cellulose, - drying the sterilized and shredded material containing plastic and cellulose, and - separating cellulose from plastic from said sterilized, shredded and dried material in at least one centrifugal separator (66).