Two-Stage Membrane Gas Separation for Lower Power and Area
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Solution Overview
Problem
Existing gas separation systems require large membrane areas and high recovery power, making them inefficient and difficult to scale down.
Innovation Solution
A two-stage gas separation system using a depressurization type for the first-stage separation membrane unit and a pressurization type for the second-stage separation membrane unit, with separation factors α1 < α2, to reduce both recovery power and membrane area.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If a two-stage separation membrane system with depressurization type units is used, then recovery power is reduced, but total membrane area increases making system size reduction difficult
Solution Approach 1:
The system divides the gas separation process into two stages with different operational modes. The first stage uses depressurization type separation membrane units to remove CO2, SO2, and NOx, while the second stage uses pressurization type separation membrane units to separate CO2 and SO2. This segmentation allows each stage to be optimized for its specific function, reducing overall membrane area while maintaining energy efficiency.
Solution Approach 2:
The invention changes the operational parameter (pressure mode) between stages. The first stage operates in depressurization mode with permeation-side space depressurized to 10-1000 mbar, while the second stage operates in pressurization mode with feed-side space pressurized to 1.01-5.0 MPa. This parameter change enables more efficient membrane utilization and reduces total membrane area required.
2Use of energy by moving object
If depressurization type separation membrane units are used in two stages, then recovery power is reduced, but system complexity increases
Solution Approach 1:
Instead of using depressurization type units for both stages, the invention inverts the approach in the second stage by using pressurization type units. This inversion simplifies the overall system design by matching each stage's operational mode to its specific separation requirements, reducing unnecessary complexity while maintaining energy efficiency.
3Area of stationary object
If pressurization type is used for second-stage separation membrane unit, then membrane area is reduced, but system complexity increases
Solution Approach 1:
The invention applies different operational qualities to different parts of the system. The first stage uses depressurization mode with specific pressure conditions optimized for bulk removal of multiple gases, while the second stage uses pressurization mode optimized for selective separation of CO2 and SO2. This local optimization reduces total membrane area while the modular design keeps system complexity manageable.
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 significant reduction in recovery power and membrane area while maintaining efficient gas separation, particularly effective for gas mixtures with low carbon dioxide content.
Implementation Method 1
a first separation membrane unit accommodating a first separation membrane that separates a gas mixture into a first permeated gas and a first non-permeated gas; the first separation membrane and the second separation membrane are preferentially permeable to the second gas
Implementation Method 2
a second separation membrane unit accommodating a second separation membrane that separates the first permeated gas into a second permeated gas and a second non-permeated gas; the first separation membrane and the second separation membrane are preferentially permeable to the second gas
Implementation Method 3
a depressurizing device that depressurizes a permeation-side space of the first separation membrane unit
Implementation Method 4
a pressurizing device that pressurizes a feed-side space of the second separation membrane unit
Data Source
Figure 1
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AI summary
The present invention provides a new gas separation system and a new gas mixture separation method that are suitable for achieving both reduction of the recovery power and reduction of the membrane area. A gas separation system (100) of the present invention includes: a first separation membrane unit (10) accommodating a first separation membrane (11) that separates a gas mixture (S1) into a first permeated gas (S2) and a first non-permeated gas (S3); a second separation membrane unit (20) accommodating a second separation membrane (21) that separates the first permeated gas (S2) into a second permeated gas (S4) and a second non-permeated gas (S5); a depressurizing device (30) that depressurizes a permeation-side space of the first separation membrane unit (10); and a pressurizing device (40) that pressurizes a feed-side space of the second separation membrane unit (20). The gas mixture (S1) contains a first gas and a second gas different from the first gas. The first separation membrane (11) and the second separation membrane (21) are preferentially permeable to the second gas, and a separation factor α1 of the first separation membrane (11) and a separation factor α2 of the second separation membrane (21) satisfy α1 < α2.