Parallel Membrane Separation for CO2 Capture in Combustion Systems
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Solution Overview
Problem
Current power generation processes, especially combined cycle power plants, face inefficiencies in energy recovery and environmental impact due to high carbon dioxide emissions in combustion exhaust gases, which are difficult to treat effectively.
Innovation Solution
Incorporating a sweep-based membrane separation unit into combustion systems to selectively remove carbon dioxide from exhaust gases, using membranes permeable to carbon dioxide over nitrogen and oxygen, with a sweep gas to enhance the separation process, allowing for recirculation of the permeate stream to increase carbon dioxide concentration and reduce emissions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a total pressure difference is applied between feed and permeate sides to drive membrane separation, then carbon dioxide removal efficiency is improved, but energy consumption and operating costs increase
Solution Approach 1:
The exhaust gas itself serves as the sweep gas on the permeate side, eliminating the need for external sweep gas flow and associated energy consumption. The system uses its own exhaust stream to maintain the pressure balance and drive the separation process, making the system self-sufficient and energy-efficient
Solution Approach 2:
The invention operates the membrane separation unit at approximately equal pressures on both feed and permeate sides, fundamentally changing the operating pressure parameters from conventional high-pressure differential operation to near-atmospheric balanced operation, thereby eliminating compression energy requirements
2Productivity
If a sweep gas is introduced to enhance carbon dioxide removal from exhaust gases, then carbon dioxide capture efficiency is improved, but capital costs and system complexity increase
Solution Approach 1:
The exhaust gas stream serves multiple functions simultaneously: it is the feed stream containing carbon dioxide to be removed, and it also serves as the sweep gas on the permeate side to maintain low partial pressure of carbon dioxide. This multi-functionality eliminates the need for separate sweep gas systems and reduces overall system complexity
Solution Approach 2:
The exhaust gas acts as an intermediary medium that facilitates the membrane separation process by providing the necessary sweep function without requiring external intervention. It mediates between the feed side and permeate side, enabling efficient carbon dioxide transfer while maintaining system simplicity
3Object-generated harmful factors
If conventional carbon dioxide treatment methods are applied to combustion exhaust gases, then carbon dioxide emissions are reduced, but technical feasibility and economic practicality deteriorate
Solution Approach 1:
The invention changes the operating parameters from conventional high-pressure differential operation to near-atmospheric balanced operation with minimal pressure differential, eliminating the need for expensive compression equipment and reducing capital costs while maintaining effective carbon dioxide separation
Solution Approach 2:
The system uses its own exhaust stream to provide the sweep function, eliminating the need for external energy inputs and complex equipment. This self-service approach makes the system economically practical by avoiding expensive operating costs associated with conventional treatment methods
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 reduces carbon dioxide content in exhaust gases to less than 5 vol %, enhancing energy efficiency and environmental sustainability by utilizing existing air/oxygen as a sweep gas, thereby reducing capital and energy costs while improving carbon dioxide capture efficiency.
Implementation Method 1
membranes permeable to carbon dioxide over nitrogen and oxygen
Implementation Method 2
a sweep gas to enhance the separation process
Data Source
AI summary
Disclosed herein are combustion systems and power plants that incorporate sweep-based membrane separation units to remove carbon dioxide from combustion gases. In its most basic embodiment, the invention is a combustion system that includes three discrete units: a combustion unit, a carbon dioxide capture unit, and a sweep-based membrane separation unit. In a preferred embodiment, the invention is a power plant including a combustion unit, a power generation system, a carbon dioxide capture unit, and a sweep-based membrane separation unit. In both of these embodiments, the carbon dioxide capture unit and the sweep-based membrane separation unit are configured to be operated in parallel, by which we mean that each unit is adapted to receive exhaust gases from the combustion unit without such gases first passing through the other unit.