CO2 Separation Membrane Pressure Control Using Water Vapor Sweep
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Solution Overview
Problem
Conventional carbon dioxide separation methods using membranes face issues with insufficient carbon dioxide permeation performance due to excessive pressure application and the need for additional energy sources for humidified sweep gases, which fail to achieve expected energy savings.
Innovation Solution
Adjusting the pressure of the permeation gas to an appropriate range, ensuring a pressure difference between the feed and permeate sides of the membrane, and utilizing water vapor to create a sweep effect without an external sweep gas, by controlling temperature and humidity within specific ranges.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stress or pressure
If excessive pressure is applied to the permeate side of the carbon dioxide separation membrane, then the pressure difference between the permeate side and feed side decreases, but the carbon dioxide permeation performance deteriorates
Solution Approach 1:
The invention optimizes the pressure parameter on the permeate side by maintaining it at atmospheric pressure or slightly below (sub-atmospheric pressure) rather than applying excessive pressure. This parameter change preserves the pressure difference across the membrane while preventing the deterioration of carbon dioxide permeation performance, thereby resolving the contradiction between pressure management and productivity.
2Stability of the object's composition
If a humidified sweep gas is fed to the permeate side to prevent water evaporation, then water vapor is maintained, but an additional source of sweep gas and an additional humidification step are required
Solution Approach 1:
The invention extracts and eliminates the need for the external humidified sweep gas system by utilizing the water vapor naturally present in the feed gas mixture. By removing the carbon dioxide through membrane separation while allowing water vapor to remain in the permeate stream, the system achieves stable water vapor content without requiring additional sweep gas sources or humidification equipment, thereby reducing device complexity.
Solution Approach 2:
The system utilizes the water vapor already contained in the feed gas to maintain the required humidity in the permeate stream. The feed gas itself serves as the source of water vapor, eliminating the need for external humidification systems. This self-service approach resolves the contradiction by maintaining water vapor stability while avoiding additional system complexity.
3Stability of the object's composition
If a humidified sweep gas is fed to the permeate side, then water evaporation is prevented, but energy saving is not achieved due to additional sweep gas requirements
Solution Approach 1:
The invention extracts and eliminates the energy-consuming humidified sweep gas system by utilizing the water vapor naturally present in the feed gas. The feed gas itself serves as the moisture source, removing the need for external humidification equipment and the associated energy consumption. This resolves the contradiction by maintaining water vapor stability while achieving energy savings.
Solution Approach 2:
The system uses the water vapor already contained in the feed gas to maintain humidity in the permeate stream, making the system self-sufficient regarding moisture supply. This eliminates the need for external energy input for humidification, thereby achieving energy savings while maintaining stable water vapor content.
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 approach enhances carbon dioxide permeation performance while reducing energy consumption and eliminating the need for additional sweep gases, leading to a more efficient separation process.
Implementation Method 1
a facilitated transport separation membrane for separating carbon dioxide is a separation membrane which utilizes a reversible reaction of carbon dioxide and a carbon dioxide carrier
Implementation Method 2
causing water vapor which permeates the carbon dioxide separation membrane to produce a sweep effect
Data Source
Figure 1~2
Figure 3
AI summary
A carbon dioxide separation method including the steps of: feeding a mixed gas that contains at least carbon dioxide and water vapor to a carbon dioxide separation membrane that contains a hydrophilic resin and a carbon dioxide carrier; separating, from the mixed gas, a permeation gas that contains the carbon dioxide by use of the carbon dioxide separation membrane; adjusting temperature of gas which contacts the carbon dioxide separation membrane so that a temperature difference between the mixed gas and the permeation gas is not lower than 0°C and not higher than 20°C; and adjusting pressure of the permeation gas, the pressure of the permeation gas and water vapor partial pressure in the mixed gas satisfying the following formula (1): 2.5 kPaA < (pressure of permeation gas) < (water vapor partial pressure in mixed gas) ··· (1).