Ultra-thin Gas Separation Membrane for Mild Pressure Diffusion

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing gas separation methods using membranes struggle to effectively separate minor components in mixed gases under mild conditions with a pressure difference of 1 atmosphere or less, which is crucial for applications like air conditioning and carbon dioxide concentration.

Innovation Solution

A gas separation method employing a very thin gas separation membrane with a film thickness of 1 um or less, made of polydimethylsiloxane and supported by a polyimide porous material, allows selective permeation of specific gases at concentrations up to 10000 ppm, optimizing gas permeability through logarithmic relationships between membrane thickness and permeability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If a conventional gas separation membrane is used, then the membrane has sufficient strength and stability, but it cannot effectively separate minor gas components under mild pressure conditions

Engineering Contradiction:
Improveseparation efficiency of minor gas componentsVSAvoidmembrane strength
Core Design Contradiction:
ProductivityVSStrength

Solution Approach 1:

The patent applies a very thin film structure (1 μm or less) as the gas separation membrane. This thin film design dramatically increases the permeability and separation efficiency for minor gas components while maintaining adequate mechanical strength through proper material selection and support structure design. The thin film enables effective gas separation under mild pressure conditions (≤1 atmosphere pressure difference) where conventional thicker membranes fail.

Inventive Principle:
Principle #30Flexible shells and thin films

2Productivity

If the membrane thickness is reduced to improve permeability, then gas permeability increases, but the membrane strength and stability deteriorate

Engineering Contradiction:
Improvegas permeabilityVSAvoidmembrane stability
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent employs an extremely thin film (1 μm or less) to maximize gas permeability while maintaining system reliability through a carefully designed composite structure. The thin film is integrated with a porous support layer that provides mechanical strength and stability, allowing the membrane to operate reliably under mild pressure conditions without compromising structural integrity.

Inventive Principle:
Principle #30Flexible shells and thin films

Solution Approach 2:

The gas separation membrane is constructed as a composite structure combining a very thin active separation layer (1 μm or less) with a porous support layer. This composite design allows the thin film to provide high permeability for minor gas components while the support layer ensures mechanical stability and prevents membrane failure under operating conditions.

Inventive Principle:
Principle #40Composite materials

3Productivity

If a thin membrane is used to separate minor gas components, then separation under mild conditions becomes possible, but the device complexity increases

Engineering Contradiction:
Improveseparation capability under mild conditionsVSAvoidmembrane structure complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent utilizes a very thin film (1 μm or less) to enable gas separation under mild pressure conditions (≤1 atmosphere pressure difference). This thin film design achieves effective separation of minor gas components without requiring complex external pressure control systems or additional processing equipment, thereby limiting the increase in device complexity while dramatically improving separation capability.

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

This method enables efficient separation of minor gas components under mild conditions, increasing the permeability of specific gases and reducing their concentration in the mixed gas, while maintaining stability and strength, suitable for applications like carbon dioxide enrichment in air conditioning systems.

Implementation Method 1

allowing selective permeation of a specific gas (A) from a mixed gas

Methodology Applied
Scientific EffectSelective permeation: Permeation

Implementation Method 2

the gas (A) can be satisfactorily separated even under mild conditions where the pressure difference between both sides of the gas separation membrane is 1 atmosphere or less

Methodology Applied
Scientific EffectDiffusion: Diffusion

Data Source

PatentEP3673975B1Gas separation method and gas separation membrane
Publication Date: 2023.05.17 TOKYO OHKA KOGYO CO LTD

AI summary

The present invention provides: a gas separation method which is capable of desirably separating a slight amount of a component from a mixed gas under mild conditions such that the pressure difference between both sides of a gas separation membrane is 1 atmosphere or less; and a gas separation membrane which is suitable for use in this gas separation method. According to the present invention, in a gas separation method wherein a specific gas (A) in a mixed gas, which contains the specific gas (A) at a concentration of 1,000 ppm by mass or less, is selectively permeated with use of a gas separation membrane, an extremely thin gas separation membrane that has a film thickness of 1 µm or less is used, so that the gas (A) is desirably separated under mild conditions such that the pressure difference between both sides of the gas separation membrane is 1 atmosphere or less.