Hydrophobic Membrane Separation of Volatile Siloxanes

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Solution Overview

Problem

Current methods for separating volatile siloxanes from liquid mixtures often require harsh temperature conditions, leading to degradation of components and inefficiencies, such as pot stripping and wiped film evaporators.

Innovation Solution

A method using a dense hydrophobic membrane where a liquid feed mixture containing a polymer and volatile siloxane is contacted with a sweep medium, such as a gas, liquid, or vacuum, to produce a permeate enriched in volatile siloxanes and a retentate depleted in them, utilizing a nonporous or dense membrane to minimize leakage and fouling.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If harsh temperature conditions are used for separation (pot stripping or wiped film evaporators), then volatile siloxanes can be removed from the mixture, but components of the mixture are degraded

Engineering Contradiction:
Improveremoval of volatile siloxanesVSAvoiddegradation of components
Core Design Contradiction:
Quantity of substanceVSObject-affected harmful factors

Solution Approach 1:

The invention changes the separation mechanism from thermal-based to membrane-based, allowing separation at mild temperatures by exploiting differences in permeability through the dense hydrophobic membrane rather than relying on harsh temperature conditions

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

A dense hydrophobic membrane is introduced as an intermediary medium to facilitate selective separation of volatile siloxanes from the liquid mixture, enabling separation without direct thermal exposure that would cause degradation

Inventive Principle:
Principle #24Intermediary (Mediator)

2Quantity of substance

If conventional separation methods are used, then volatile siloxanes can be separated, but energy consumption is high and component degradation occurs

Engineering Contradiction:
Improveseparation of volatile siloxanesVSAvoidenergy consumption
Core Design Contradiction:
Quantity of substanceVSUse of energy by moving object

Solution Approach 1:

The invention changes the operating parameters from high-temperature thermal processes to ambient or mild temperature membrane permeation, dramatically reducing energy consumption while achieving effective separation

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention replaces the mechanical/thermal separation system (evaporators, strippers) with a membrane-based separation system that operates on permeability differences, eliminating the need for high energy input

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

3Quantity of substance

If porous membranes are used, then separation can occur, but leakage and clogging increase maintenance needs

Engineering Contradiction:
Improveseparation efficiencyVSAvoidmembrane leakage and fouling
Core Design Contradiction:
Quantity of substanceVSReliability

Solution Approach 1:

The invention uses dense hydrophobic membranes rather than porous membranes, eliminating pore-related leakage and clogging issues while maintaining effective separation through the membrane's dense structure and hydrophobic properties

Inventive Principle:
Principle #31Porous materials

Solution Approach 2:

The invention employs composite membrane materials with specific hydrophobic characteristics that provide both separation efficiency and resistance to fouling, combining multiple material properties to address both separation and reliability requirements

Inventive Principle:
Principle #40Composite materials

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 allows for efficient removal of volatile siloxanes under mild conditions, reducing energy consumption and component degradation, with enhanced separation efficiency and reduced maintenance needs compared to conventional methods.

Implementation Method 1

contacting a first side of a first dense hydrophobic membrane with a liquid feed mixture comprising a polymer and at least one volatile siloxane

Methodology Applied
Scientific EffectPermeation: Permeation

Data Source

PatentEP3122440B1Method of separating volatile siloxane from a liquid feed mixture
Publication Date: 2018.11.21 DOW SILICONES CORP
  • EP3122440B1 patent drawingFigure 1
  • EP3122440B1 patent drawingFigure 2
  • EP3122440B1 patent drawingFigure 3

AI summary

Various embodiments disclosed relate to methods of separating a volatile siloxane from a liquid mixture. In various embodiments, the method includes contacting a first side of a first hydrophobic membrane with a liquid feed mixture including a polymer and at least one volatile siloxane. The method can also include contacting a second side of the membrane with a sweep medium including at least one of a sweep gas, a sweep liquid, and a vacuum, to produce a permeate mixture on the second side of the membrane and a retentate mixture on the first side of the membrane, wherein the permeate mixture is enriched in the volatile siloxane, and the retentate mixture is depleted in the volatile siloxane.