Absorber Column Segmentation for CO2 and SO2 Capture
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Solution Overview
Problem
Current CO2 capture technologies, such as post combustion capture (PCC), are hindered by the presence of sulfur dioxide (SO2) in flue gases, as SO2 is absorbed preferentially and rapidly, degrading CO2 capture performance and requiring additional desulfurization steps, which increase costs and complexity, especially in locations without existing flue gas desulfurization (FGD) infrastructure.
Innovation Solution
A process utilizing a single absorber column with separate sections and a liquid flow distributor allows for the preferential absorption of SO2 in the first section and CO2 in the second section, using a single solvent stream, leveraging differences in solubility and reaction rates between CO2 and SO2 to enable effective capture of both gases without prior SO2 removal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single solvent stream is used to capture both CO2 and SO2 in a single absorber column, then the process complexity and cost are reduced, but the capture performance degrades because SO2 is absorbed preferentially and rapidly
Solution Approach 1:
The absorber column is divided into two distinct sections: a first section for preferential SO2 absorption and a second section for CO2 absorption. This segmentation allows each section to be optimized for its specific function, resolving the contradiction by maintaining capture performance while using a single integrated column structure.
Solution Approach 2:
Different regions of the absorber column are assigned different functional qualities - the first section is optimized for SO2 absorption while the second section is optimized for CO2 absorption. This local differentiation enables the system to handle both gases effectively without requiring separate processing units.
2Reliability
If additional desulfurization steps are added to remove SO2 before CO2 capture, then the capture performance is improved, but the process complexity and cost increase
Solution Approach 1:
The SO2 removal function and CO2 capture function are merged into a single absorber column with two sections. This integration eliminates the need for separate desulfurization units and process steps, maintaining capture performance while reducing overall process complexity.
Solution Approach 2:
The single absorber column performs multiple functions - it acts as both a desulfurization unit (first section) and a CO2 capture unit (second section). This multi-functionality resolves the contradiction by achieving both SO2 removal and CO2 capture in one piece of equipment.
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 enables efficient CO2 capture from flue gases containing high levels of SO2 without the need for pre-treatment, reducing costs and technical complexity by using a single solvent stream and existing gas cleaning technologies, thereby facilitating CO2 capture in scenarios where FGD is not installed.
Implementation Method 1
SO2 is absorbed preferentially and rapidly, degrading CO2 capture performance
Implementation Method 2
When CO2 is absorbed into an aqueous solution a number of reactions can occur... When SO2 is absorbed into an aqueous solution analogous reactions occur to those for CO2
Implementation Method 3
providing an absorbent liquid for CO2 and the second acid gas to the second section to flow counter current to the gas stream
Implementation Method 4
leveraging differences in solubility and reaction rates between CO2 and SO2 to enable effective capture of both gases
Data Source
AI summary
An absorption column 1 for separating CO2 and a second acid gas from a gas stream, the column comprising a first and second section (4, 5) for the absorption of CO2 and the second acid gas; a solvent inlet in the second section for the addition of liquid stream 3 including an absorbent liquid for CO2 and the second acid gas; a gas inlet (21) in the first section for the addition of a gas stream (2) containing CO2 and the second acid gas; a gas outlet (15) in the second section of the column; a first solvent outlet (22) for the removal of at least a portion of the solvent (6) from the second section of the column and a second solvent outlet (23) for solvent stream (11) from the first section of the column; and a liquid flow distributor arrangement (8) to allow a portion of the solvent to flow from the second section of the column to the first section. A method of operating the apparatus and method of solvent extraction is also disclosed.