CO2 Separation via NO2 Recycling for Purity and Energy Efficiency
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Solution Overview
Problem
Current CO2 capture technologies in power plants face challenges in achieving high CO2 purity and energy efficiency, particularly in oxycombustion processes, where recycling of flue gases is complex and energy-intensive, and NOx emissions are not effectively managed.
Innovation Solution
A process and apparatus that separates CO2 from flue gases by producing a NO2 enriched stream, which is recycled to the combustion zone to convert SO2 into sulfuric acid, reducing the need for additional NOx sources and enhancing CO2 purity through low-temperature purification and phase separation, while minimizing energy consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If flue gas is compressed to high pressure for storage, then CO2 storage capability is improved, but energy consumption increases excessively
Solution Approach 1:
The process separates CO2 from flue gas through multiple stages including absorption, stripping, and purification units, creating a concentrated CO2 stream that requires less compression energy for storage compared to compressing entire flue gas volumes
Solution Approach 2:
The system changes the concentration parameter of CO2 by removing impurities and separating it from the flue gas matrix, transforming it from a dilute 4-14% CO2 stream to a high-purity stream suitable for efficient storage and transport
2Productivity
If chemical solvent absorption is used to remove CO2, then CO2 recovery is improved, but process complexity and energy intensity increase
Solution Approach 1:
The patent introduces a chemical solvent (amine-based) as an intermediary medium that selectively absorbs CO2 from flue gas, enabling efficient separation through the formation and breakdown of chemical complexes between the solvent and CO2
Solution Approach 2:
The system implements continuous circulation of the chemical solvent through absorption towers and stripping columns, maintaining continuous CO2 removal capability while regenerating the solvent in-situ to avoid external chemical additions
3Object-generated harmful factors
If NOx is added to oxidize SO2 to sulfuric acid, then SO2 removal is improved, but additional reagents and process complexity are required
Solution Approach 1:
The patent converts harmful NOx emissions into a useful oxidizing agent that transforms SO2 into sulfuric acid, thereby eliminating both pollutants simultaneously through the oxidation reaction: 2NO2 + 2SO2 + 2H2O → 2H2SO4 + 2NO
Solution Approach 2:
The system uses the flue gas's own NOx content (or recycled NOx) to perform the oxidation function, eliminating the need for external oxidizing reagents and reducing overall process complexity
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 improves CO2 recovery efficiency, reduces energy expenditure, and achieves higher CO2 purity, making it more economical and environmentally friendly for CO2 capture and storage.
Implementation Method 1
the NO 2 enriched stream reacts with SO2 in the unit for treating the fluid to form SO 3 and NO
Implementation Method 2
the SO 3 subsequently reacts with water to form sulfuric acid
Implementation Method 3
separating CO2 from flue gases by producing a NO2 enriched stream
Data Source
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AI summary
A process for separating carbon dioxide from a fluid containing carbon dioxide, NO2, and at least one of oxygen, argon, and nitrogen comprises the steps of separating at least part of the fluid into a carbon dioxide enriched stream, a carbon dioxide depleted stream comprising CO2 and at least one of oxygen, argon, and nitrogen and a NO2 enriched stream and recycling said NO2 enriched stream upstream of the separation step.