Composite CO2 Separation Membrane for Low-Pressure Mixed Gases
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Solution Overview
Problem
Existing gas separation membranes struggle to achieve high selectivity and permeability for carbon dioxide at low concentrations and atmospheric pressures, particularly in applications like carbon neutrality and carbon negativity, where carbon dioxide concentrations are low and pressures are moderate.
Innovation Solution
A gas separation membrane comprising a separation layer with C—N and C—C bonds and a support layer made of organopolysiloxane, with specific thickness and intensity ratio relationships, optimized for carbon dioxide separation from mixed gases with low carbon dioxide concentrations and atmospheric pressures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a gas separation membrane is designed for high concentration carbon dioxide separation (50 mol %) at high pressure (3 atm), then the membrane can achieve adequate separation performance under those specific conditions, but the separation performance cannot be sufficiently extracted when carbon dioxide concentration or supply pressure is low (0-10 vol % at 0.5-2.0 atm)
Solution Approach 1:
The patent modifies the chemical composition parameters of the membrane by incorporating specific functional groups (C—N bonds with intensity ratio I(C—N)/I(C—C) of 0.05-0.40) and controlling the thickness ratio of separation layer to support layer (0.01-0.15). These parameter changes enable the membrane to maintain high gas selectivity ratio and gas permeability across a wide range of carbon dioxide concentrations (0-50 mol %) and pressures (0.5-3.0 atm), resolving the adaptability issue.
Solution Approach 2:
The patent employs a composite membrane structure consisting of a support layer containing organopolysiloxane and a separation layer with specific polymer composition containing C—N bonds. This composite material design combines the mechanical strength of the organopolysiloxane support with the selective separation properties of the functionalized separation layer, achieving both high separation performance and mechanical durability under varying operating conditions.
2Productivity
If the separation layer is made thinner to improve gas permeability, then the mechanical strength of the membrane decreases
Solution Approach 1:
The patent divides the membrane into two distinct functional layers: a thin separation layer (5-200 nm) optimized for gas permeability and selectivity, and a thicker support layer (50-2000 nm) providing mechanical strength. The thickness ratio tA/tB is controlled at 0.01-0.15, allowing the separation layer to be sufficiently thin for high productivity while the support layer maintains structural integrity.
Solution Approach 2:
The patent applies different material properties to different parts of the membrane structure. The separation layer is composed of polymers with specific C—N bond content (intensity ratio 0.05-0.40) to maximize gas separation performance, while the support layer uses organopolysiloxane to provide mechanical strength. This local optimization of material properties resolves the contradiction between thinness for permeability and thickness for strength.
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 membrane achieves high selectivity and permeability for carbon dioxide, balancing mechanical strength and efficiency in separating carbon dioxide from atmospheric and industrial gases, reducing energy input requirements.
Implementation Method 1
the separation layer including a polymer having a C—N bond and a C—C bond and having a function of selecting and separating carbon dioxide
Implementation Method 2
the support layer containing an organopolysiloxane
Data Source
AI summary
Provided is a gas separation membrane including: a separation layer having a function of selecting and separating carbon dioxide; and a support layer disposed on the side opposite to the space side to which a mixed gas is supplied and containing an organopolysiloxane;wherein when the layer thickness of the separation layer is tA [nm] and the layer thickness of the support layer is tB [nm], the separation layer and the support layer satisfy the following formulas (1) and (2), and when the separation layer is subjected to X-ray photoelectron spectroscopy to obtain an XPS spectrum and the C1s peak is subjected to waveform separation, the intensity ratio I (C—N)/I (C—C) satisfies the following formula (3).1<tA+tB<1000(1)0.01<tA/tB<0.2 0(2)0.03<I(C-N)/I(C-C)<0.5(3)