Two-Stage CO2 Recovery Process with Elevated Pressure Absorption
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Solution Overview
Problem
Conventional carbon dioxide recovery processes require high energy for compression due to low-pressure carbon dioxide output, which increases the overall energy demand and costs associated with sequestration and industrial uses.
Innovation Solution
A two-stage carbon dioxide recovery process involving countercurrent contact with a liquid absorbent in multiple zones, followed by depressurization and heating at elevated pressures to recover carbon dioxide at pressures higher than atmospheric, reducing the need for additional compression stages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If conventional carbon dioxide recovery processes are used, then carbon dioxide can be separated from the fluid stream, but the recovered carbon dioxide is at low pressure requiring additional compression energy
Solution Approach 1:
The absorber is divided into multiple absorption zones with different operating pressures. The first absorption zone operates at high pressure (3-20 bar) to recover bulk carbon dioxide, while the second absorption zone operates at lower pressure for polishing. This segmentation allows carbon dioxide to be recovered at elevated pressures, reducing the need for subsequent compression.
Solution Approach 2:
The process changes the pressure parameter across different absorption zones. By operating the first absorption zone at elevated pressure (3-20 bar) compared to conventional single-stage processes, the recovered carbon dioxide is already pressurized, significantly reducing the energy required for compression to sequestration pressures.
2Stress or pressure
If a two-stage absorption method is employed, then carbon dioxide can be recovered at elevated pressure, but the device complexity increases
Solution Approach 1:
The process combines bulk removal and polishing functions within a single integrated absorber unit with multiple absorption zones. Rather than using separate equipment for each function, both the high-pressure bulk removal and low-pressure polishing occur in one device, reducing overall system complexity while achieving elevated pressure recovery.
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 reduces the overall energy required for carbon dioxide recovery and compression, enabling efficient sequestration and industrial uses by recovering at least part of the carbon dioxide at elevated pressures, thereby minimizing energy consumption.
Implementation Method 1
bringing it into countercurrent contact with a liquid absorbent in a first absorption zone and thereafter in a second absorption zone to absorb at least part of the carbon dioxide contained in the fluid into the absorbent
Implementation Method 2
depressurizing the loaded absorbent to release a first stream of carbon dioxide and yield a partially regenerated absorbent
Implementation Method 3
heating a second stream of the partially regenerated absorbent to release a second stream of carbon dioxide and yield a regenerated absorbent
Implementation Method 4
heating of the second stream of the partially regenerated absorbent takes place at an elevated pressure of at least 3 bar (absolute) and the second stream of carbon dioxide is recovered at the elevated pressure
Data Source
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AI summary
A process for removing carbon dioxide from a fluid comprises the steps of: (a) treating the fluid by bringing it into countercurrent contact with a liquid absorbent in a first absorption zone and thereafter in a second absorption zone to absorb at least part of the carbon dioxide contained in the fluid into the absorbent; (b) depressurizing the loaded absorbent to release a first stream of carbon dioxide and yield a partially regenerated absorbent; (c) recycling a first stream of the partially regenerated absorbent into the first absorption zone; (d) heating a second stream of the partially regenerated absorbent to release a second stream of carbon dioxide and yield a regenerated absorbent; (e) recycling the regenerated absorbent into the second absorption zone; (f) condensing water vapour entrained in the second stream of carbon dioxide by cooling the second stream of carbon dioxide and transferring at least part of the heat recovered to the partially regenerated absorbent by indirect heat exchange. The invention provides a two-stage carbon dioxide recovery process wherein the overall energy required for carbon dioxide recovery is reduced and/or wherein at least part of the carbon dioxide is recovered at a pressure higher than atmospheric pressure so as to reduce the energy required for compression of the carbon dioxide, e. g., for sequestration. Also disclosed is a plant for removing carbon dioxide from a fluid.