PTFE Membrane Contactors for Low-Energy Acrylic Acid Extraction

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Solution Overview

Problem

Existing methods for purifying acrylic acid are energy-inefficient and require frequent shutdowns due to polymerization, leading to high operational costs and complexity.

Innovation Solution

A membrane contactor process using a porous polytetrafluoroethylene (PTFE) membrane with a defined contact area for liquid-liquid extraction of acrylic acid from an aqueous stream into an organic solvent, eliminating the need for phase separation and reducing polymerization by operating at ambient temperature.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If distillation is used to purify acrylic acid, then high purity is achieved, but energy consumption increases significantly

Engineering Contradiction:
ImprovepurityVSAvoidenergy consumption
Core Design Contradiction:
Manufacturing precisionVSUse of energy by moving object

Solution Approach 1:

A liquid membrane acts as an intermediary carrier phase between the aqueous feed stream and the organic extractant. The membrane selectively transports acrylic acid from the aqueous phase into the organic phase through diffusion, enabling separation without direct mixing of the two immiscible phases. This mediator approach replaces energy-intensive distillation with a mass-transfer-based extraction process.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces the thermal field (distillation requiring heating) with a mass transfer field (extraction based on diffusion). By using a liquid membrane contactor, the separation process shifts from thermal energy-driven distillation to concentration-gradient-driven diffusion, significantly reducing energy consumption while maintaining high purity.

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

2Manufacturing precision

If distillation columns are used for acrylic acid purification, then separation is achieved, but polymerization occurs requiring frequent shutdowns

Engineering Contradiction:
ImproveseparationVSAvoidoperational continuity
Core Design Contradiction:
Manufacturing precisionVSReliability

Solution Approach 1:

The patent changes the operating parameters from high-temperature distillation to ambient-temperature extraction. By conducting the separation at lower temperatures through the liquid membrane contactor, the process suppresses thermal polymerization of acrylic acid, eliminating the need for frequent shutdowns to clear polymerized material from columns.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The liquid membrane serves as a protective intermediary that enables separation without exposing acrylic acid to the high temperatures that cause polymerization. The membrane contactor facilitates mass transfer at ambient conditions, preventing the harmful thermal effects that lead to operational interruptions.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Use of energy by moving object

If extraction process is used instead of distillation, then energy consumption is reduced, but phase separation complexity is introduced

Engineering Contradiction:
Improveenergy consumptionVSAvoidprocess complexity
Core Design Contradiction:
Use of energy by moving objectVSDevice complexity

Solution Approach 1:

The liquid membrane acts as a stabilizing intermediary that maintains distinct phase boundaries between the aqueous feed and organic extractant. This prevents direct mixing and emulsion formation, simplifying the process by eliminating the need for additional phase separation equipment while maintaining the energy advantages of extraction.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The liquid membrane functions as a flexible thin film barrier that provides a large surface area for mass transfer while maintaining phase separation. This thin-film approach enables efficient extraction without requiring complex mechanical mixing or separation devices, reducing overall process complexity.

Inventive Principle:
Principle #30Flexible shells and thin films

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

The process achieves efficient acrylic acid extraction with reduced energy consumption and extended operational reliability by preventing polymerization, allowing for continuous operation with lower mechanical complexity and cost.

Implementation Method 1

The acrylic acid first diffuses from the aqueous medium into the selective membrane and then into the other phase

Methodology Applied
Scientific EffectDiffusion: Diffusion

Implementation Method 2

A membrane contactor process using a porous polytetrafluoroethylene (PTFE) membrane with a defined contact area for liquid-liquid extraction of acrylic acid from an aqueous stream into an organic solvent

Methodology Applied
Scientific EffectLiquid-liquid extraction: Liquid-Liquid Extraction

Implementation Method 3

A membrane contactor process using a porous polytetrafluoroethylene (PTFE) membrane with a defined contact area

Methodology Applied
Scientific EffectPorosity: Porosity

Data Source

PatentEP4482818B1Separation of acrylic acid using membrane contactors
Publication Date: 2026.04.01 EVONIK SUPERABSORBER GMBH
  • EP4482818B1 patent drawingFigure 1
  • EP4482818B1 patent drawingFigure 2
  • EP4482818B1 patent drawingFigure 3

AI summary

The invention relates to the extraction of acrylic acid from aqueous streams. The aim of the invention is to provide a process for extracting acrylic acid from aqueous streams with a low energy expenditure and allowing longer operating times. This aim is achieved in that, in order to extract the acrylic acid, the aqueous stream containing the acrylic acid is brought into contact with a membrane whose side facing away from the aqueous stream is subjected to an organic solvent.