Sweep-Based Membrane Separation for Flue Gas Carbon Dioxide Capture
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Solution Overview
Problem
Current methods for treating flue gases contaminated with carbon dioxide from combustion processes are technically and economically inefficient, requiring more effective techniques to reduce carbon dioxide emissions and minimize environmental impact.
Innovation Solution
A membrane-based gas separation process combining a sweep-based membrane separation with an absorption step, where a portion of the flue gas is treated using membranes selectively permeable to carbon dioxide, and the carbon dioxide-enriched permeate stream is recycled back to the combustion process, enhancing carbon dioxide concentration and reducing emissions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional flue gas treatment methods are used, then carbon dioxide removal is achieved, but the process is technically and economically inefficient
Solution Approach 1:
The flue gas stream is divided into two separate streams: one treated by absorption and another by membrane separation. This segmentation allows each process to handle a portion of the carbon dioxide removal task, improving overall efficiency while maintaining manageable process complexity through modular design
Solution Approach 2:
The invention changes the concentration parameter of carbon dioxide in the flue gas by using membrane separation to enrich one stream before absorption treatment. This parameter change enhances the effectiveness of the absorption process and reduces the volume of gas requiring treatment, thereby improving productivity without proportionally increasing device complexity
2Productivity
If flue gas is transported for carbon dioxide capture, then capture is achieved, but transportation cost and complexity increase
Solution Approach 1:
The membrane separation unit extracts and concentrates carbon dioxide from the flue gas stream, creating a smaller, more concentrated stream that requires less transportation volume. This extraction step reduces the quantity of gas that needs to be transported while maintaining high capture productivity
Solution Approach 2:
By changing the concentration parameter through membrane enrichment, the invention reduces the total volume of gas requiring transportation. The enriched stream contains higher carbon dioxide concentration, allowing the same capture productivity to be achieved with reduced transport quantity and associated costs
3Object-affected harmful factors
If flue gas is discharged to environment, then process simplicity is maintained, but environmental damage occurs
Solution Approach 1:
The flue gas stream is segmented into two treatment paths: absorption for bulk carbon dioxide removal and membrane separation for polishing and enrichment. This segmentation enables effective environmental protection by treating different portions of the gas stream with appropriately sized units, managing process complexity through modular architecture
Solution Approach 2:
The membrane separation process changes the carbon dioxide concentration parameter, creating an enriched stream that can be efficiently captured and a depleted stream that meets emission standards. This parameter transformation reduces environmental impact while maintaining reasonable process complexity through targeted treatment
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 significantly increases carbon dioxide concentration in the exhaust stream, simplifies and reduces the cost of transporting the gas for capture, and minimizes carbon dioxide in vent streams, thereby reducing environmental impact.
Implementation Method 1
a membrane having a feed side and a permeate side, and being selectively permeable to carbon dioxide over nitrogen and to carbon dioxide over oxygen
Implementation Method 2
membranes selectively permeable to carbon dioxide
Implementation Method 3
passing a sweep gas across the permeate side of the membranes, thereby lowering the partial pressure of a desired permeant on that side to a level below its partial pressure on the feed side
Implementation Method 4
an absorption-based carbon dioxide capture step
Data Source
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AI summary
A gas separation process for treating flue gases (117) from combustion processes (112), and combustion processes including such gas separation. The invention involves routing a first portion (106) of the flue gas stream to be treated to an absorption -based carbon dioxide capture step (113), while simultaneously flowing a second portion (103) of the flue gas across the feed side of a membrane (118), flowing a sweep gas stream (101), usually air, across the permeate side, then passing the permeate/sweep gas to the combustor (112).