Sweep Membrane CO2 Removal from Mixed Combustion Exhaust
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Solution Overview
Problem
Current sweep-based membrane separation processes for carbon dioxide removal from multiple combustion sources are costly and inefficient, as they require modifying multiple combustion units and reduce oxygen levels, leading to decreased efficiency and increased costs.
Innovation Solution
A process that treats multiple exhaust gas streams from different combustion sources using a single membrane separation unit, where a carbon dioxide-depleted stream from one combustion unit is mixed with another exhaust stream, and the permeate stream is recycled back to the first combustion unit, reducing the need for multiple system modifications and maintaining efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If multiple separate carbon capture systems are implemented to treat exhaust streams from each combustion source, then carbon dioxide removal effectiveness is improved, but system complexity and capital costs increase significantly
Solution Approach 1:
The patent combines multiple exhaust gas streams from different combustion sources into a single mixed stream that is then treated by one membrane separation unit. This merging approach reduces the number of separate capture systems needed while maintaining effective carbon dioxide removal across all combustion sources.
Solution Approach 2:
The membrane separation unit serves multiple combustion sources simultaneously by treating a mixed exhaust stream that contains carbon dioxide from various sources. This multi-functional application eliminates the need for dedicated capture systems for each individual combustion unit.
2Object-affected harmful factors
If air stream entering the combustion unit is diluted with permeate stream, then carbon dioxide concentration in exhaust gas is reduced, but oxygen concentration decreases affecting combustion efficiency
Solution Approach 1:
The patent applies different quality requirements to different parts of the system: the permeate stream is selectively reused in the combustion chamber where it provides oxygen for combustion, while the residue stream is discharged to the environment where low carbon dioxide content is the primary requirement. This localized quality approach allows oxygen depletion in the permeate to be acceptable since it is recycled to a combustion process that benefits from the carbon dioxide enrichment.
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 effectively reduces carbon dioxide content in exhaust gases to 5 vol% or less, minimizing environmental impact and operational costs by allowing carbon dioxide recycling and reducing the need for multiple system modifications.
Implementation Method 1
providing 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
a driving force for transmembrane permeation may be supplied by 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
Data Source
AI summary
A gas separation process for treating exhaust gases from multiple combustion sources. The invention involves directing an exhaust gas stream from one combustion step to a carbon capture step. An off-gas stream depleted in carbon dioxide from the carbon capture step is mixed with a second exhaust stream from a second combustion step to form a mixed gas stream. The mixed gas stream is passed as a feed stream across the feed side of a membrane that is selectively permeable to carbon dioxide over nitrogen and carbon dioxide over oxygen. A sweep gas stream, usually air, flows across the permeate side, and picks up the preferentially permeating carbon dioxide. The permeate stream withdrawn from the permeate side of the membrane is then recycled back to the combustor.