Rotary Packed Bed CO2 Capture for Compact Flue Gas Absorption
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Solution Overview
Problem
Conventional processes for capturing carbon dioxide from flue gases are inefficient due to limited mass transfer caused by gravitational force in static packed columns, requiring large space and high installation and operational costs.
Innovation Solution
The use of Rotary Packed Bed (RPB) absorbers that rotate circularly, where the solvent moves from the inner radius to the outer radius under centrifugal force, enhancing mixing with flue gas in a counter-current flow, and incorporating a solvent regeneration process to recycle the solvent.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If static packed columns are used for CO2 capture, then the system is simple in structure, but mass transfer efficiency is limited due to gravitational force constraints
Solution Approach 1:
The patent transforms the static packed column into a dynamic rotating packed bed system. The packing material rotates at high speed, creating centrifugal forces that enhance liquid distribution and gas-liquid contact. This dynamic approach dramatically improves mass transfer efficiency compared to static columns, resolving the contradiction between productivity and device complexity.
Solution Approach 2:
The rapid rotation of the packed bed creates mechanical vibrations and turbulence in the liquid and gas flows. This vibration effect enhances mixing and mass transfer rates, allowing the system to achieve high productivity while maintaining a relatively simple overall structure.
2Productivity
If large static packed columns are used to compensate for low mass transfer efficiency, then sufficient contact time is achieved, but the plant footprint and installation cost increase
Solution Approach 1:
By rotating the packed bed at high speeds, the system achieves intense gas-liquid mixing and rapid mass transfer in a compact volume. This eliminates the need for large column dimensions, reducing the plant footprint while maintaining high CO2 capture efficiency.
Solution Approach 2:
The system changes the operating parameters by introducing rotational speed as a new variable. This parameter change enables high mass transfer coefficients in a small volume, resolving the contradiction between capture efficiency and plant footprint.
3Reliability
If static packed columns with wash stages are used, then solvent traces are removed, but the system requires large space and high operational costs
Solution Approach 1:
The rotating packed bed wash stages create intense mixing and short contact times, achieving effective solvent removal with reduced liquid inventory and lower energy requirements compared to large static wash columns.
Solution Approach 2:
The rapid rotation enables the wash process to occur quickly, with gas passing through the wash stages in a short time. This 'rushing through' approach achieves solvent removal effectiveness while minimizing space and operational costs.
4Productivity
If gravitational force is used for solvent flow in static columns, then the system requires no moving parts, but mass transfer is limited
Solution Approach 1:
The system introduces rotational motion as the driving force for mass transfer enhancement. The rotating packing creates centrifugal forces that improve liquid distribution and gas-liquid contact, achieving high mass transfer rates while incorporating a single moving component (the rotating pack).
Solution Approach 2:
The patent replaces the gravitational flow mechanism with a rotation-driven mechanism. This substitution transforms the mass transfer process from gravity-limited to rotation-enhanced, dramatically improving productivity with minimal increase in mechanical 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 increases mass transfer efficiency, reduces solvent degradation, lowers energy and capital costs, and allows for a smaller plant footprint by utilizing smaller RPB strippers and wash units, with improved CO2 capture and recovery.
Implementation Method 1
a solvent provided through an inner radius of the at least one RPB absorber moves towards an outer radius of the at least one RPB absorber
Implementation Method 2
CO2 is separated from a mixture of gases, using a solvent which selectively reacts with the CO2
Implementation Method 3
the solvent is heated to a temperature so that at an operating pressure of the stripper column 112, water present in the solvent gets vaporized to steam
Implementation Method 4
Inside the reboiler 114, the solvent is heated
Implementation Method 5
a condenser cools the steam and gas to around 40°C. This condenses the steam into water 116 and gaseous CO2 118
Data Source
Figure 1
Figure 2
Figure 3A
AI summary
A system and a process for capturing Carbon Dioxide (CO2) from flue gases are disclosed. The process comprises feeding a flue gas comprising CO2 to at least one Rotary Packed Bed (RPB) absorber rotating circularly. A solvent may be provided through an inner radius of the RPB absorber. The solvent may move towards an outer radius of the RPB absorber. The solvent may react with the flue gas in a counter-current flow. The process further includes passing the flue gas through at least one of a water wash and an acid wash to remove traces of the solvent present in the flue gas. Finally, the solvent reacted with the CO2 may be thermally regenerated for re-utilizing the solvent back in the process.