Integrated Size Classification and Extrusion for Solvent Removal

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Solution Overview

Problem

Current plastic recycling methods fail to efficiently remove impurities and solvents, resulting in recycled polymers of lower quality, which limits their application and introduces environmental concerns due to the persistence of toxic chemicals associated with microplastics.

Innovation Solution

A continuous method integrating size classification and extrusion with optional degassing, using a membrane or sieve in an extruder to remove solvents and impurities from dissolved target polymers, reducing the need for energy-intensive evaporation and improving the quality of recycled polymers to a virgin-like standard.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If traditional solvent removal methods (evaporation, precipitation) are used, then solvent is removed from polymer solution, but energy consumption increases and manufacturing precision decreases

Engineering Contradiction:
Improveenergy consumptionVSAvoidpolymer quality
Core Design Contradiction:
Use of energy by moving objectVSManufacturing precision

Solution Approach 1:

The patent combines size classification and extrusion into a single integrated process within the extruder. The size classification unit (membrane or sieve) is incorporated directly into the extruder, allowing simultaneous solvent removal and polymer extrusion in one step, eliminating the need for separate evaporation and processing steps, thereby reducing energy consumption while maintaining polymer quality

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent replaces thermal evaporation (energy-intensive thermal process) with mechanical size classification and filtration. The membrane or sieve physically separates solvent from polymer based on size differences, substituting a mechanical separation method for a thermal process, thus significantly reducing energy consumption

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Manufacturing precision

If size classification and extrusion are integrated, then manufacturing precision improves, but device complexity increases

Engineering Contradiction:
Improvepolymer qualityVSAvoidextruder structure
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The extruder is designed to perform multiple functions simultaneously: it acts as both an extrusion device and a size classification unit. The membrane or sieve integrated into the extruder enables the same device to both extrude the polymer and classify/separator solvent based on size, making the device multi-functional and improving polymer quality without requiring entirely separate systems

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

Solution Approach 2:

The patent uses a membrane or sieve with specific pore sizes integrated into the extruder. This porous material enables size-based separation of solvent from polymer while being incorporated into the existing extruder structure, allowing quality improvement through a relatively simple additive component rather than a completely complex new system

Inventive Principle:
Principle #31Porous materials

3Productivity

If solvent-based recycling is used, then productivity increases, but object-affected harmful factors increase due to toxic chemicals

Engineering Contradiction:
Improverecycling throughputVSAvoidtoxic chemicals
Core Design Contradiction:
ProductivityVSObject-affected harmful factors

Solution Approach 1:

The patent extracts and removes toxic chemicals and impurities from the polymer solution during the size classification and extrusion process. The membrane or sieve physically separates harmful substances based on size differences, extracting them from the polymer stream before the final product is formed, thereby maintaining high recycling throughput while eliminating harmful factors from the final product

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 method enhances the efficiency and sustainability of plastic recycling by achieving high-quality, virgin-like polymers with reduced energy consumption and increased throughput, addressing the challenges of impurity removal and solvent evaporation in existing techniques.

Implementation Method 1

said extruder comprises a size classification unit which is permeable for said solvent and impermeable for said target polymer

Methodology Applied
Scientific EffectFiltration: Filter (physical)

Implementation Method 2

said extruder comprises a size classification unit which is permeable for said solvent and impermeable for said target polymer

Methodology Applied
Scientific EffectPermeation: Permeation

Implementation Method 3

optionally wherein said extruder comprises a degassing unit

Methodology Applied
Scientific EffectDegassing: Evaporation

Data Source

PatentEP3950796A1Method for solvent removal from a polymer solution by integrated size classification and extrusion in a plastic extruder
Publication Date: 2022.02.09 LYB SOLVENT RECYCLING GMBH
  • EP3950796A1 patent drawingFigure 1
  • EP3950796A1 patent drawingFigure 2~3
  • EP3950796A1 patent drawing

AI summary

The invention relates to a continuous method for removing a solvent from a suspension or solution comprising a target polymer, wherein the method comprises the steps of delivering said suspension or solution to an extruder, wherein said extruder comprises a size classification unit that is designed to be permeable for the solvent and impermeable for the target polymer; and filtration and extrusion of said suspension or solution in said extruder. The invention also relates to a plastic waste recycling system for recycling a target polymer. Furthermore, the invention also relates to a polymer material obtained by this recycling method.