CO2 capture process
The method of compressing, condensing, and separating CO2 and water mixtures addresses the issue of vapor phase emissions, enhancing CO2 capture efficiency and reducing costs by recycling the gaseous phase in the CO2 capture process.
Patent Information
- Application Number
- FR2024006099
- Authority / Receiving Office
- FR · FR
- Patent Type
- Utility models
- Current Assignee / Owner
- Filing Date
- 2024-06-10
- Publication Date
- 2025-10-24
- Estimated Expiration
- 2034-06-10
AI Technical Summary
The emission of a vapor phase during the expansion of condensates from CO2 capture units results in CO2 loss, reducing the capture unit's efficiency and incurring additional costs due to emissions.
A method involving compression, condensation, and separation of CO2 and water mixtures, followed by partial condensation, distillation, and solidification to capture CO2, with the gaseous phase being recycled upstream of the compression stage.
Enhances CO2 capture efficiency by recovering the gaseous phase and reducing emissions, thereby optimizing the capture process and minimizing costs.
Smart Images
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Abstract
Description
Title of the invention: CO2 capture method
[0001] The present invention relates to a method for capturing CO2.
[0002] Units for capturing and purifying CO2 from wet sources (e.g., fumes) most often include a wet source compression stage. This compression is often multi-stage and includes cooling between each stage. These cooling stages most often generate condensates that must be purified in a wastewater treatment unit before their release into the natural environment or use.
[0003] It is conventional to expand the condensates generated at different pressures to a common pressure corresponding to the lowest pressure (often close to atmospheric pressure) before mixing them and exporting them to the treatment system. A step of pumping the common condensates is also conventional in order to overcome the pressure losses between the CO2 capture process and the condensate treatment station or even the pressure losses of the station itself.
[0004] During the expansion of condensates, a weak vapor phase can be generated. Indeed, certain molecules are solubilized at high pressure while they are not at lower pressure. This vapor phase is typically emitted into the atmosphere.
[0005] The problem solved by this invention is that the emission into the atmosphere of the vapor phase of the condensates induces a loss of CO2. The efficiency of the capture unit is therefore reduced, generating additional costs linked to CO2 emissions.
[0006] According to an object of the invention, a method for capturing CO2 is provided in which a mixture of CO2 and water is compressed in at least one compression stage, the compression generating condensation of the water present in the mixture, at least one condensate consisting of the condensed water is separated from the compressed mixture, the compressed mixture is separated by partial condensation and / or distillation and / or solidification to form CO2 to be captured, the at least one condensate is expanded producing a liquid phase and a gaseous phase and the gaseous phase is returned upstream of the compression stage.
[0007] The invention will be described in more detail with reference to the figure.
[0008] [Fig.l] represents a method according to the invention.
[0009] An adsorption unit P produces a gas mixture containing CO2, water and at least one other component. The mixture is compressed in a series of compression stages 1, 2, 3 in series. After each compression stage, the mixture is cooled by a cooler RI, R2, R3 which has the effect of condensing part of the water that the mixture contains. Thus compression stage 1 produces a condensate W1, stage 2 a condensate W2 and stage 3 a condensate W3. The three condensates W1, W2, W3 are each expanded in a valve then mixed and sent to a phase separator S forming a liquid phase L and a gaseous phase G. The liquid phase L is sent to an enclosure E. The gaseous phase G, richer in CO2 than the liquid phase, is returned upstream of the first compression stage 1 and downstream of the adsorption P.
[0010] The compressed gas mixture in steps 1, 2, 3 always contains water which is removed by temperature-swing adsorption in the adsorbent beds A1, A2. The dried gas mixture 11 is then separated by partial condensation and / or distillation and / or solidification in the separation unit K.
[0011] The separation unit K produces a gas which is heated by the heater R and then used for the regeneration of the beds A1, A2, thus recovering the water they contain. This water can be condensed, forming a condensate W4 which can also be mixed with the condensate W1.
[0012] Among the interesting characteristics of the process, we can name: • Expand the condensates generated by the cooling of wet fluids at various process pressures (intermediate and final compressor cooling, cooling of gas used for the regeneration of a TSA, etc.) • Collect the expanded condensates in a capacity allowing the separation of the gas phase and the liquid phase generated by the expansions • Recycle the gas phase generated upstream of the wet fume compressor.
Claims
Claims
1. A method for capturing CO2 in which a mixture of CO2 and water is compressed in at least one compression stage (1, 2, 3), the compression generating condensation of the water present in the mixture, at least one condensate (W1, W2, W3) consisting of the condensed water is separated from the compressed mixture, the compressed mixture (11) is separated by partial condensation and / or distillation and / or solidification (K) to form CO2 to be captured, the at least one condensate is expanded producing a liquid phase (L) and a gaseous phase (G) and the gaseous phase is returned upstream of the compression stage.