Dual-Membrane Gas Separation for Low-Selectivity Mixtures
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Solution Overview
Problem
Existing gas separation systems are inefficient in separating gas mixtures, particularly when the separation factor of the separation membranes is low, leading to suboptimal recovery rates and purities.
Innovation Solution
A gas separation system utilizing two separation membranes with specific separation factor ratios (α1/α2 ≥ 1.9 and α2 ≤ 50) to efficiently separate gas mixtures, where the first membrane is preferentially permeable to gas A and the second membrane is preferentially permeable to gas B, achieving high recovery rates and purities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single separation membrane with low separation factor (α ≤ 50) is used, then the device complexity is reduced, but the recovery rate and purity of gas separation are insufficient
Solution Approach 1:
The gas separation process is divided into two sequential stages using two different separation membranes. The first membrane (with separation factor α1 for gas A) performs initial separation to obtain permeated gas and non-permeated gas. The second membrane (with separation factor α2 for gas B) further separates the non-permeated gas from the first membrane. This segmentation allows each membrane to target a specific gas component, achieving high overall recovery purity (≥85 vol% for both gas A and gas B) even when individual membranes have low separation factors (α ≤ 50).
Solution Approach 2:
The system employs a composite membrane configuration where two different separation membranes are combined in series. The first membrane has preferential permeability to gas A while the second membrane has preferential permeability to gas B. This composite approach creates a synergistic effect where the combination of two membranes with complementary selectivities achieves separation performance superior to what either membrane could achieve alone, resolving the contradiction between device simplicity and separation precision.
2Ease of operation
If a single separation membrane is used, then the operation is simpler, but the recovery rate of gas components is insufficient
Solution Approach 1:
The separation process is segmented into two operational stages: first membrane separation and second membrane separation. The first membrane recovers gas A from the feed gas, and the second membrane recovers gas B from the non-permeated gas of the first stage. This segmentation enables high recovery rates for both gas components by targeting each gas in a dedicated separation stage, while maintaining operational simplicity through a straightforward series configuration without complex control systems.
3Manufacturing precision
If two separation membranes with specific separation factor ratios are used, then the recovery purity is improved, but the device complexity increases
Solution Approach 1:
Each separation membrane is designed with specific local quality characteristics tailored to its function. The first membrane has preferential permeability to gas A with separation factor α1, while the second membrane has preferential permeability to gas B with separation factor α2. The system requires that α1/α2 ≥ 1.9 and α2 ≤ 50, ensuring each membrane is optimized for its specific separation task. This local quality approach achieves high recovery purity (≥85 vol% for both gases) while keeping the overall device relatively simple through a basic series configuration.
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 system achieves high recovery rates and purities for gases A and B, with the first permeated gas containing 85 vol% or more of gas A and the second permeated gas containing 85 vol% or more of gas B, suitable for continuous processing of gas mixtures.
Implementation Method 1
a first separation membrane preferentially permeable to a gas A that separates a gas mixture containing the gas A and a gas B different from the gas A into a first permeated gas and a first non-permeated gas
Implementation Method 2
a second separation membrane preferentially permeable to the gas B that separates the first non-permeated gas into a second permeated gas and a second non-permeated gas
Data Source
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AI summary
The present invention provides a new gas separation system suitable for separating a gas mixture efficiently. A gas separation system 100 of the present invention includes: a first separation membrane 11 that separates a gas mixture 70 into a first permeated gas 80 and a first non-permeated gas 81; and a second separation membrane 21 that separates the first non-permeated gas 81 into a second permeated gas 90 and a second non-permeated gas 91. The gas mixture 70 contains a gas A and a gas B different from the gas A. The first separation membrane 11 is preferentially permeable to the gas A. The second separation membrane 21 is preferentially permeable to the gas B. A separation factor α1 of the first separation membrane and a separation factor α2 of the second separation membrane satisfy the following relational expressions (1) and (2). α1/α2≥1.9 α2≤50