MIEC Membrane Oxygen Separation in Oxy-Combustion Engine
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Solution Overview
Problem
Internal combustion engines face challenges in reducing NOx emissions and efficiently capturing CO2, particularly due to the high demand for oxygen in oxy-combustion processes and the limitations of existing membrane technologies in separating oxygen and CO2 from air.
Innovation Solution
The implementation of a regenerative Brayton cycle with a mixed ionic-electronic conducting (MIEC) membrane that separates oxygen from compressed air, integrated with an oxy-combustion system, allowing for the production of pure or diluted oxygen and the separation of CO2, while utilizing the heat from exhaust gases to maintain membrane operation efficiency and recover energy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a MIEC membrane is used to separate oxygen from compressed air in an oxy-combustion system, then oxygen productivity and CO2 capture efficiency are improved, but the device complexity and manufacturing difficulty increase
Solution Approach 1:
The system is divided into distinct functional modules: a MIEC membrane unit for oxygen separation, a combustion chamber for oxy-combustion, and a CO2 capture system. This segmentation allows each component to be optimized independently while maintaining overall system productivity.
Solution Approach 2:
The patent employs MIEC (mixed ionic-electronic conducting) membranes composed of composite ceramic materials that exhibit both ionic and electronic conductivity properties. These composite materials enable efficient oxygen separation at high temperatures, directly improving oxygen productivity while managing the complexity through material science advancements.
2Reliability
If high temperature operation is maintained for MIEC membrane efficiency, then oxygen separation performance is improved, but energy consumption and thermal management requirements increase
Solution Approach 1:
The patent combines the MIEC membrane oxygen separation process with the oxy-combustion chamber in an integrated system where the high-temperature environment required for membrane operation is provided by the combustion process itself. This merging eliminates the need for separate heating systems, reducing overall energy consumption while maintaining membrane efficiency.
Solution Approach 2:
The oxy-combustion system generates the high temperatures needed for MIEC membrane operation through its own combustion process, making the system self-sufficient for thermal requirements. The exhaust heat from combustion is utilized to maintain membrane temperature, reducing external energy input requirements.
3Object-generated harmful factors
If nitrogen is completely removed from the air current, then NOx emissions are prevented, but the loss of nitrogen for potential reuse increases
Solution Approach 1:
The MIEC membrane system selectively extracts oxygen from the compressed air current, effectively separating it from nitrogen and other gases. This extraction prevents nitrogen from participating in combustion reactions that would generate NOx emissions, while the nitrogen-rich permeate stream can be separately managed or reused in other processes.
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 prevents NOx emissions, maximizes oxygen productivity, and captures CO2, achieving efficient energy use and reducing the environmental impact of internal combustion engines by minimizing harmful gas emissions and promoting CO2 removal.
Implementation Method 1
oxygen ions are diffused from one side to the other through the properties of the crystal structure due to a chemical potential gradient of oxygen between both sides of the membrane
Implementation Method 2
Transport of the oxygen ion is simultaneous to the transport of electrons or electron holes (electron carriers)
Implementation Method 3
The oxygen selectivity of these membranes is 100%. These membranes work at high temperatures (usually in the range of 700-1000°C) with high air pressures (1-2 MPa) fed in on the retention side and vacuum on the permeation side
Implementation Method 4
utilizing the heat from exhaust gases to maintain membrane operation efficiency and recover energy
Implementation Method 5
a regenerative Brayton cycle with a mixed ionic-electronic conducting (MIEC) membrane that separates oxygen from compressed air
Implementation Method 6
an oxy-combustion system, allowing for the production of pure or diluted oxygen and the separation of CO2
Data Source
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AI summary
The invention relates to an internal combustion engine that comprises a first Brayton cycle comprising a mixed ionic-electronic conducting (MIEC) membrane that separates the O2 from the air such that the suctioned air current is free from N2; a second Brayton cycle combined in a binary manner with the first Brayton cycle and nested with a cycle selected from an Otto cycle and a diesel cycle performed by means of oxy-combustion. The second Brayton cycle transmits mechanical energy and thermal energy from exhaust gases to the first Brayton cycle. The first Brayton cycle provides to the second Brayton cycle compressed O2 from the MIEC membrane. By means of the present engine, the NOx emission into the atmosphere is prevented by the separation of N2 in the MIEC membrane.