Exhaust Gas Recirculation for Low-Power CO2 Membrane Separation
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Solution Overview
Problem
Existing gas separation systems, such as those described in Patent Literature 1, require high recovery power for separating carbon dioxide from exhaust gases, which is inefficient and costly.
Innovation Solution
A gas separation system comprising a combustion device, a second gas circulation passage, and a gas separation device that includes a separation membrane or physical adsorption method to enhance carbon dioxide recovery by recycling exhaust gases within the system, utilizing pressurization to reduce the required separation power.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a decompression-type membrane separation unit is used to separate exhaust gas from a boiler, then carbon dioxide can be removed from the exhaust gas, but high recovery power is required
Solution Approach 1:
The system performs preliminary concentration of carbon dioxide by circulating and condensing water vapor from the exhaust gas before the membrane separation process. This pre-concentration step increases the carbon dioxide concentration in the gas fed to the membrane separator, reducing the energy required for separation and improving overall recovery efficiency
Solution Approach 2:
Water vapor condensation is used as an intermediary process to concentrate carbon dioxide. By removing water vapor through condensation and circulation, the system creates a pre-conditioned gas stream with higher carbon dioxide concentration, which serves as an ideal feed for the membrane separation unit, thereby reducing the energy demand of the separation process
2Quantity of substance
If exhaust gas is circulated and condensed to concentrate carbon dioxide, then the carbon dioxide concentration increases, but the system complexity increases
Solution Approach 1:
The circulating water vapor condensation system serves multiple functions simultaneously: it concentrates carbon dioxide, recovers water for reuse, and prepares the gas stream for membrane separation. This multi-functionality reduces the need for separate dedicated equipment for each function, thereby limiting the increase in system complexity while achieving carbon dioxide concentration
Solution Approach 2:
Instead of discarding water vapor from the exhaust gas, the system recycles it through condensation and re-evaporation. This recovery process concentrates carbon dioxide in the remaining gas stream while also recovering water for potential reuse, achieving concentration enhancement with minimal additional complexity by repurposing an existing component of the exhaust gas
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 effectively reduces the recovery power needed for carbon dioxide separation by optimizing the gas circulation and employing pressurization, making the process more efficient and cost-effective.
Implementation Method 1
a gas separation device that separates the second gas to obtain a third gas having a higher content of carbon dioxide than the second gas
Implementation Method 2
employing a separation membrane or physical adsorption method to enhance carbon dioxide recovery
Implementation Method 3
a second gas circulation passage for feeding at least a portion of the second gas to the combustion device
Implementation Method 4
employing pressurization to reduce the required separation power
Data Source
AI summary
The present invention provides a novel gas separation system suitable for reducing recovery power. A gas separation system includes: a combustion device that is supplied with a first gas containing oxygen and that discharges a second gas containing carbon dioxide; a second gas circulation passage for feeding at least a portion of the second gas to the combustion device; and a gas separation device that separates the second gas to obtain a third gas having a higher content of carbon dioxide than the second gas.