Method for treating a gas containing carbon dioxide

Abstract

The present invention relates to a method for treating exhaust gases, comprising: - a first cooling step in a heat exchanger (6); - a second compression step in a compression device (12); - a third drying step in a drying unit (14); - a fourth decarbonation step in a carbon dioxide capture device (20); - a fifth step, sampling the exhaust gases at a temperature of about 180°C; - a sixth step, regenerating the drying unit (14); - a seventh step, sampling the exhaust gases at a temperature of 5°C; - an eighth step: cooling the drying unit (14).

Description

Technical Field

[0001] This invention relates to the field of gases containing carbon dioxide, and more particularly to methods for treating such gases. Background Technology

[0002] When sources of carbon dioxide-containing gases (such as internal combustion engines in vehicles with floating structures) operate, they produce gases containing carbon dioxide. These gases are typically released into the atmosphere, causing environmental damage, especially because they contain carbon dioxide. Therefore, it makes sense to process carbon dioxide-containing gases from emission sources to extract the carbon dioxide for later use or sale.

[0003] The emission source can be, for example, a thermal engine, or more generally, any device that releases a stream of hot, carbon dioxide-containing gas. Hereinafter, the invention will be described by way of example in the context of thermal engines, and more specifically, engines fueled by natural gas. However, the invention is by no means limited thereto.

[0004] Natural gas-powered engines are, for example, propulsion engines or auxiliary drive engines that are equipped with floating or land-based structures capable of accommodating and / or transporting liquefied natural gas (LNG).

[0005] Such facilities typically include tanks containing liquefied natural gas (also known as liquid natural gas). This natural gas is liquid at atmospheric pressure and temperatures below -163°C. The tanks are never fully insulated, so the natural gas evaporates at least partially. These tanks contain both liquid and gaseous forms of natural gas. In known ways, at least some of the natural gas present in the tanks in gaseous form can therefore be used, in particular, to power propulsion engines for floating structures or auxiliary engines for floating or land-based structures.

[0006] These engines consume natural gas and release exhaust gases, which can be used to drive turbines before being released into the atmosphere. Because these exhaust gases are produced by burning the natural gas supplied to the engine, they contain carbon dioxide. Therefore, it is necessary to implement methods for treating these exhaust gases in order to limit pollution caused by the carbon dioxide they contain.

[0007] To separate carbon dioxide from exhaust gas, a treatment method is known in the prior art, in which the exhaust gas passes through a carbon dioxide capture device. However, such a carbon dioxide capture device requires a dry exhaust gas stream, thus necessitating the exhaust gas to pass through a drying unit, for example, comprising molecular sieves. The drying unit typically operates in two modes: an adsorption mode and a desorption mode. In the adsorption mode, the drying unit adsorbs moisture present in the exhaust gas; in the desorption mode, the moisture is discharged from the drying unit itself. The desorption mode includes a regeneration phase and a cooling phase. During the regeneration phase, the drying unit is heated, and during the cooling phase, the drying unit is cooled. The desorption mode requires a heat source in the first phase and a cold source in the second phase, which are not always available. Furthermore, this leads to an increase in the number of components required to implement the exhaust gas treatment method, which occupies a considerable overall size in floating or land-based structures.

[0008] In this context, the present invention provides a method for treating a gas containing carbon dioxide, which avoids the need for additional cold gas and simplifies the design of a treatment system for implementing the treatment method. Summary of the Invention

[0009] Therefore, the main object of the present invention is a method for treating carbon dioxide-containing gas emitted from an emission source, comprising the following steps during the flow of the carbon dioxide-containing gas within a treatment loop:

[0010] The first step involves cooling the carbon dioxide-containing gas within a heat exchanger during the first step.

[0011] The second step involves compressing the cooled gas containing carbon dioxide within a compression device.

[0012] The third step involves drying the compressed gas containing carbon dioxide within a drying unit.

[0013] In the fourth step, carbon dioxide is removed from the dried carbon dioxide-containing gas in the carbon dioxide capture device to produce decarbonized gas.

[0014] In the fifth step, during this fifth step, a first portion of the decarbonized gas is sampled from a first point in the processing loop, at which the temperature of the decarbonized gas is above 180°C, and the first portion of the decarbonized gas is sent to the drying unit.

[0015] The sixth step involves the regeneration and drying of the first portion of the decarbonized gas.

[0016] In the seventh step, a second portion of the decarbonized gas is sampled from the second point in the processing loop. The temperature of the decarbonized gas is approximately 5°C, and it is sent to the drying unit.

[0017] The eighth step involves the second portion of the decarbonized gas being cooled and regenerated in the drying unit.

[0018] The processing method according to the invention is configured to allow the capture of carbon dioxide present in the carbon dioxide-containing gas from the emission source of the carbon dioxide-containing gas (e.g., a propulsion engine or auxiliary drive motor of a floating or land-based structure).

[0019] This treatment method involves circulating a stream of carbon dioxide-containing gas emitted from an emission source within a treatment loop to a carbon dioxide capture device, while allowing for optimal and simplified operation of other components arranged in the treatment loop. The treatment method involves numerous steps that, on the one hand, decarbonize the carbon dioxide-containing gas, and on the other hand, ensure the proper operation of the components involved in the decarbonization process. However, it should be noted that the components of the treatment loop participating in performing one or another step of the treatment method can operate continuously or cyclically in different modes. Therefore, in the context of this invention, the term "step" refers to an operation performed on the carbon dioxide-containing gas, or to a time phase of operation of a cyclical functional element.

[0020] The process begins with a first or cooling step, during which the carbon dioxide-containing gas passes through a heat exchanger, such as a heat recovery boiler, where it exchanges heat to be cooled. In a second or compression step, the carbon dioxide-containing gas leaving the heat exchanger passes through a compression unit. It is then compressed. Upon exiting the compression unit, the carbon dioxide-containing gas undergoes a third or drying step, during which its moisture content is adsorbed by a drying unit. These first, second, and third steps are necessary to bring the carbon dioxide-containing gas to the optimal temperature and humidity for decarbonization, which occurs in a carbon dioxide capture unit during a fourth or carbon dioxide capture step.

[0021] At the end of the fourth step, the gas initially containing carbon dioxide is decarbonized and can therefore be released into the atmosphere without any pollution risk. However, the present invention aims to reuse at least a portion of these decarbonized exhaust gases for the regeneration and cooling of the drying unit. These two steps, corresponding to the desorption mode, are necessary to allow the implementation of the adsorption mode of the drying unit, which allows the drying of the carbon dioxide-containing gas. The regeneration step corresponds to the sixth step of the processing method, which is carried out after the fifth step or the step of sampling the first portion of the decarbonized gas. During this fifth step, the decarbonized gas is sampled at a temperature above 180°C, advantageously about 200°C, and up to 240°C. The term "about" refers to a temperature of 200°C ± 10°C. This temperature is necessary to allow the drying unit to regenerate (i.e., to reheat it to remove moisture). Then, in the seventh step, which is also a sampling step, a second portion of the decarbonized gas is sampled at a temperature of about 5°C. The term "about" refers to a temperature of 5°C ± 10°C. This second portion of the decarbonized gas is used to perform the eighth step of the processing method, namely the cooling step. This cooling step is feasible because the decarbonized gas exits the carbon dioxide capture device at a low temperature. The cooling step must be performed after the regeneration step within the drying unit; however, it should be understood that due to the nature of the processing method applied to a processing loop with continuous gas flow, some steps can be performed simultaneously.

[0022] As an example and regarding the above definition of the term "step", the seventh step corresponds to the continuous operation of the extraction loop for the second part of the decarbonized gas, and therefore applies to the entire element, while the eighth step corresponds to a time phase of the operation of the drying unit, and therefore applies only to a part of the drying unit.

[0023] According to an optional feature of the invention, the processing method includes a first heat exchange step and a second heat exchange step, during which the decarbonized gas passes through a heat exchanger to cool the carbon dioxide-containing gas emitted from the emission source.

[0024] This means that the gas passes through the heat exchanger twice in a countercurrent manner to form the first pass and the second pass.

[0025] According to an optional feature of the invention, the processing method includes a first energy generation step between the first heat exchange step and the second heat exchange step, during which the decarbonized gas passes through a first turbine in the processing loop.

[0026] During the processing, the decarbonized gases first pass through a heat exchanger to form their first pass, then through a first turbine, where they contribute to the generation of mechanical energy, and finally through another heat exchanger to form a second pass. In this way, the decarbonized gases exchange heat before and after passing through the first turbine.

[0027] According to an optional feature of the invention, the processing method includes a second energy generation step following the second heat exchange step, during which decarbonized gas passes through a second turbine in the processing loop.

[0028] In other words, the decarbonized gas leaving the heat exchanger passes through a second turbine, which again helps generate mechanical energy.

[0029] According to an optional feature of the invention, the fifth step occurs after the second energy generation step.

[0030] The decarbonized gas is then sampled from the outlet of the second turbine. This corresponds to the first embodiment of the processing method according to the invention.

[0031] According to an optional feature of the invention, the fifth step occurs between the first heat exchange step and the first energy generation step.

[0032] Understandably, the decarbonized gas is sampled between the first pass of the heat exchanger and the first turbine. This is a second embodiment of the processing method according to the invention.

[0033] According to an optional feature of the invention, the processing method includes the step of humidifying the decarbonized gas by injecting water into the processing loop, and the fifth step occurs before the humidification step.

[0034] In this case, corresponding to the third embodiment of the processing method according to the invention, the decarbonized gas is sampled between the compression device and the water injection point.

[0035] According to an optional feature of the invention, the humidification step occurs before the first heat exchange step.

[0036] Water is injected to humidify the decarbonized gas stream before it passes through the heat exchanger.

[0037] According to an optional feature of the invention, the processing method includes, after the sixth step, releasing a first portion of the decarbonized gas into the atmosphere.

[0038] This corresponds to the first embodiment, in which the decarbonized gas used for regeneration is released from the processing loop once it leaves the drying unit.

[0039] According to an optional feature of the invention, the processing method includes, after the sixth step, returning a first portion of the decarbonized gas to a point in the processing loop located between the heat exchanger and the first turbine.

[0040] This return step is effective for both the second and third embodiments. Therefore, a first portion of the decarbonized gas used for the regeneration drying unit is reinjected into the processing loop upstream of the first turbine for recirculation within the processing loop.

[0041] According to an optional feature of the invention, the processing method includes a reheating step after the fourth step, during which the decarbonized gas passes through a compression device.

[0042] Then, the decarbonized gas exchanges heat with carbon dioxide-containing gas from emission sources (such as fuel consumers).

[0043] According to an optional feature of the invention, the processing method includes, after the eighth step, returning a second portion of the decarbonized gas to a point in the processing loop located between the compressor and the heat exchanger.

[0044] This corresponds to the first embodiment, in which the decarbonized gas used to cool the drying unit is recirculated within the processing loop, more specifically upstream of the first pass of the heat exchanger.

[0045] According to an optional feature of the invention, the processing method includes, after the eighth step, returning a second portion of the decarbonized gas to a point in the processing loop located between the heat exchanger and the first turbine.

[0046] In the case covering the second and third embodiments, the decarbonized gas used to cool the drying unit is also recycled, but in this case, it is re-injected upstream of the first turbine.

[0047] According to an optional feature of the invention, the execution of the fifth step and the seventh step depends on the method used to control the state of the drying unit.

[0048] It should be understood that this processing method is based on a control method that guides the implementation of either the regeneration step or the cooling step according to the state of the drying unit, both of which correspond to the desorption mode of the drying unit. Once these two steps are completed, the control method also controls the adsorption mode of the drying unit.

[0049] The present invention also relates to a processing system configured to implement the above-described processing method, the processing system comprising a processing loop for processing a gas containing carbon dioxide, wherein a heat exchanger, a compression device, a drying unit and a carbon dioxide capture device are arranged in sequence on the processing loop.

[0050] The treatment system includes a treatment loop, which corresponds to the assembly of pipes and components involved in implementing the treatment method. "In this order" means that the carbon dioxide-containing gas from the emission source flows through the treatment loop, first through a heat exchanger, then through a compression unit, then through a drying unit, and finally through a carbon dioxide capture unit. Once decarbonized, the decarbonized gas can flow through these different components in a different order.

[0051] To decarbonize the carbon dioxide-containing gas, a heat exchanger is configured to lower the temperature of the gas before supplying it to a compressor. The compressor is configured to increase the pressure of the carbon dioxide-containing gas it receives from the heat exchanger. A drying unit is configured to dry the carbon dioxide-containing gas once it has been compressed, and a carbon dioxide capture device is configured to decarbonize the dried gas to provide decarbonized gas.

[0052] According to an optional feature of the invention, the drying unit is configured to alternately exhibit a first adsorption configuration and a second desorption configuration.

[0053] The first adsorption structure removes moisture from the carbon dioxide-containing gas, while the second desorption structure is designed to dehumidify the drying unit itself. Therefore, when the drying unit is in the first adsorption structure, the third step of the processing method occurs, namely, drying the carbon dioxide-containing gas, and conversely, the sixth and eighth steps, respectively, for regeneration and cooling, occur in the second desorption structure of the drying unit.

[0054] According to an optional feature of the invention, the processing circuit includes a sampling line dedicated to guiding a first portion of the decarbonized gas to the drying unit, and a sampling conduit dedicated to guiding a second portion of the decarbonized gas to the drying unit.

[0055] It should be understood that the sampling line helps regenerate the drying unit, while the sampling conduit helps cool the drying unit.

[0056] According to an optional feature of the invention, the processing circuit includes a control valve and / or segment valve for the sampling line and a control valve for controlling the sampling conduit.

[0057] A control or segment valve on the sampling line allows the first portion of the decarbonized gas to pass through the sampling line. Similarly, a control valve in the sampling conduit can be used to allow or prevent a second portion of the decarbonized gas from passing through the sampling conduit.

[0058] According to an optional feature of the invention, the heat exchanger includes at least a first pass and a second pass, a first turbine is located on the processing loop between the first and second passes of the heat exchanger, and a second turbine connects the second pass of the heat exchanger to the outlet pipe of the processing loop.

[0059] The outlet pipe of the processing loop is led out of the processing system into the atmosphere.

[0060] According to an optional feature of the invention, the processing circuit includes an outlet conduit dedicated to discharging a first portion of the decarbonized gas from the drying unit into the atmosphere.

[0061] The outlet conduit is used in the first embodiment. For example, it is connected to an outlet pipe that is connected to a second turbine. Once they leave the drying unit, the decarbonized gas used in its regeneration can be discharged from the processing loop.

[0062] According to an optional feature of the invention, the processing circuit includes a return conduit dedicated to discharging a first portion and / or a second portion of the decarbonized gas from the drying unit.

[0063] This return conduit is present in all three embodiments. It allows the decarbonized gas used for regeneration and / or cooling of the drying unit to be reinjected into the processing loop.

[0064] According to an optional feature of the invention, a second portion of the return conduit is dedicated to discharging decarbonized gas, and the return conduit includes a first end connected to the drying unit and a second end connected between the compressor and the heat exchanger.

[0065] This is the first embodiment, in which the return duct is dedicated solely to the decarbonized gas used for cooling. The return duct then allows these gases to return to the first pass of the heat exchanger.

[0066] According to an optional feature of the invention, the return duct includes a first end connected to the drying unit and a second end connected between a first pass of the heat exchanger and a first turbine.

[0067] This corresponds to the second and third embodiments, in which the first and second portions of the decarbonized gas, namely the decarbonized gas for regeneration and the decarbonized gas for cooling, are transported between the first pass of the heat exchanger and the first turbine.

[0068] According to an optional feature of the invention, the processing circuit includes a flow control valve between the heat exchanger and the second end of the return duct.

[0069] In the second embodiment, the flow control valve is therefore located between the point where the first portion of the decarbonized gas is sampled and the point where the decarbonized gas for the desorption drying unit is returned.

[0070] According to an optional feature of the invention, the processing circuit includes a pilot valve for controlling the outlet conduit.

[0071] This pilot valve is used to allow or prevent decarbonized gas that has already participated in the desorption mode of the drying unit from entering the outlet duct.

[0072] According to an optional feature of the invention, the processing circuit includes a pilot valve for controlling the return conduit.

[0073] This pilot valve is used to allow or prevent decarbonized gas that has already participated in the desorption mode of the drying unit from entering the return duct.

[0074] According to an optional feature of the invention, the processing system includes a control system for controlling the flow of carbon dioxide-containing gas within the processing loop.

[0075] According to optional features of the invention, the system guides the opening and / or closing of the sampling line control valve, the sampling conduit control valve, the outlet conduit pilot valve, and the return conduit pilot valve.

[0076] According to an optional feature of the invention, the control system controls the opening and / or closing of the flow control valve.

[0077] Therefore, the control system controls the opening and / or closing of various valves in the processing loop in order to regenerate or cool the drying unit as needed.

[0078] According to an optional feature of the invention, the control performed by the control system depends on the flow rate of the carbon dioxide-containing gas within the processing loop.

[0079] According to an optional feature of the invention, the heat exchanger is a recovery boiler.

[0080] According to an optional feature of the invention, the drying unit includes a plurality of dryers, the plurality of dryers including at least a first dryer and a second dryer, wherein when the second dryer is in a second desorption configuration, the first dryer is in a first adsorption configuration.

[0081] This means that the two dryers are in opposite configurations; the first dryer helps dry the gas containing carbon dioxide, while the second dryer regenerates and then cools, and vice versa. These dryers are identical and alternate over time to ensure continuous drying of the gas. This allows the treatment process to be implemented without any interruption due to the need for desiccant desorption. Individually, each dryer operates in a cycle, meaning it undergoes a continuous cycle of adsorption and desorption.

[0082] The present invention also relates to a floating structure comprising an emission source for discharging gas containing carbon dioxide and a treatment system for treating the gas containing carbon dioxide emitted from the emission source (i.e., exhaust gas emitted by the fuel consumer).

[0083] The emission sources here are fuel consumers, such as propulsion engines or auxiliary drive motors of floating structures, which are supplied with vapors from liquefied gases (such as liquefied natural gas) stored in tanks of floating structures. Attached Figure Description

[0084] On the one hand, other features, details, and advantages of the invention will become clearer when reading the following description, and on the other hand, when examples of embodiments are given by way of indication and non-limitation with reference to the accompanying drawings, in which:

[0085] [ Figure 1 A first embodiment of a treatment system implementing the exhaust gas treatment method according to the present invention is shown schematically;

[0086] [ Figure 2 A second embodiment of a processing system implementing the processing method according to the present invention is illustrated schematically;

[0087] [ Figure 3 A third embodiment of a processing system implementing the processing method according to the present invention is illustrated schematically. Detailed Implementation

[0088] Features, variations, and different embodiments of the present invention can be associated with each other in various combinations, provided that they are not incompatible or mutually exclusive. In particular, variations of the invention may be conceived to contain only that selection of features if a selection of features described below, isolated from the other described features, is sufficient to impart technical advantages and / or distinguish the invention from the prior art.

[0089] In the accompanying drawings, elements common to several drawings retain the same reference numerals.

[0090] In this specification, the invention is described in a non-limiting manner within the context of a floating structure having a fuel consumer, which represents an emission source of gas containing carbon dioxide. The gas containing carbon dioxide is the exhaust gas emitted by such a fuel consumer. These gases become decarbonized exhaust gas after passing through a carbon dioxide capture device. However, the invention is similarly applicable to any device that releases a hot, carbon dioxide-containing gas stream.

[0091] Figures 1 to 3 An exhaust treatment system 1 according to the invention is schematically illustrated. The treatment system 1 is configured with a floating or land-based structure to capture carbon dioxide contained in the exhaust of a fuel consumer 2 within the structure. This fuel consumer 2 (e.g., an engine) is supplied with gas possibly derived from the natural evaporation of liquefied natural gas, which is stored in one or more tanks in the floating or land-based structure. The exhaust is generated by the fuel consumer 2 using the gas derived from the natural evaporation of liquefied natural gas.

[0092] The treatment system 1 includes a treatment circuit 4 through which exhaust gas flows. The treatment circuit 4 includes various lines and conduits for allowing the exhaust gas to be guided, and various components for treating the exhaust gas.

[0093] The processing circuit 4 includes a guide line 3 and an exhaust line 5. The guide line 3 allows exhaust gas to flow within the processing circuit 4 to decarbonize it, while the exhaust line 5 allows decarbonized exhaust gas to be guided.

[0094] Processing loop 4 is connected to fuel consumer 2 via guide line 3 to deliver its exhaust gas. Upon leaving fuel consumer 2, this exhaust gas is guided via guide line 3 to heat exchanger 6, in this case, recovery boiler 6. Heat exchanger 6 includes a first pass 8 and a second pass 10. Heat exchanger 6 is configured to cool the exhaust gas, which successively exchanges heat with the gas flowing through the first pass 8 and then with the gas flowing through the second pass 10.

[0095] Processing loop 4 also includes a compression device 12 connected to heat exchanger 6 via guide line 3. Alternatively, according to a variant of the embodiment, the compression device 12 may have one or more compression stages. The compression device 12 is configured to compress the exhaust gas it receives from heat exchanger 6.

[0096] The guide line 3 connects the outlet of the compression unit 12 to the inlet of the drying unit 14 of the processing circuit 4 of the processing system 1. The drying unit 14 is configured to remove moisture contained in the exhaust gas. For this purpose, the drying unit 14 is configured to have a first adsorption configuration and a second desorption configuration. The first adsorption configuration corresponds to effectively capturing moisture present in the exhaust gas, while the second desorption configuration is employed in the absence of exhaust gas and allows for the removal of moisture present in the drying unit 14 after moisture has been removed from the exhaust gas. More specifically, the second desorption configuration covers a first regeneration stage of the drying unit 14, during which the drying unit 14 is dried, and then covers a second cooling stage, during which the drying unit 14 is cooled to a temperature that allows the first adsorption configuration to be restored.

[0097] As shown in the figure, the drying unit 14 includes a plurality of dryers 16, including a first dryer 16A, a second dryer 16B, and a third dryer 16C. To allow continuous removal of moisture present in the exhaust gas, at least one of the dryers 16 is in a first adsorption configuration, while at least another of these dryers 16 is in a second desorption configuration. For example, the first dryer 16A and the second dryer 16B are in the first adsorption configuration, while the third dryer 16C is in the second desorption configuration. Any of these configurations can be implemented by including a valve 18 associated with each dryer 16 within the processing loop 4. These valves 18 are located at the inlet and outlet of the dryer 16 due to the countercurrent operation of the first adsorption and second desorption configurations. It should be understood that the inlet of the dryer 16 corresponds to the portion connected to the compression unit 12.

[0098] The outlet of the drying unit is connected via guide line 3 to a carbon dioxide capture device 20, which is configured to remove carbon dioxide present in the exhaust gas. The carbon dioxide capture device 20 includes a first subunit 22 and a second subunit 24. The first subunit 22 is designed to receive the dried exhaust gas as it leaves the drying unit 14, and the second subunit 24 is designed to release the decarbonized exhaust gas at low temperature. As can be understood from the above, the first subunit 22 is connected to guide line 3, while the second subunit 24 is connected to discharge line 5, which is dedicated to the flow of decarbonized exhaust gas.

[0099] Within processing loop 4, the carbon dioxide capture device 20, and more specifically its second subunit 24, is connected to the compression device 12. Exhaust gas containing carbon dioxide passes through the compression device 12 via guide line 3, and decarbonized exhaust gas passes through the compression device 12 via discharge line 5. In other words, guide line 3 allows exhaust gas to be supplied to the carbon dioxide capture device 20, while discharge line 5 allows decarbonized exhaust gas to exit the carbon dioxide capture device 20.

[0100] The discharge line 5 of the processing loop 4 also connects the compression unit 12 to the heat exchanger 6, such that the discharge line 5 is connected to the first pass 8. Opposite to the compression unit 12, the first pass 8 is connected to the first turbine 26. The first turbine 26 uses energy from the decarbonized exhaust gas to provide useful mechanical energy within a floating or land-based structure. The first turbine 26 is connected to the second pass 10 of the heat exchanger 6, so it can be understood that the decarbonized exhaust gas flows counter-currently through the first pass 8 and the second pass 10 to exchange heat twice with the exhaust gas passing through the feed line 3.

[0101] At the outlet of the second pass 10, the discharge line 5 connects the heat exchanger 6 to the second turbine 28, which, like the first turbine 26, is configured to supply mechanical energy to a floating or land-based structure. At the outlet of the second turbine 28, the discharge line 5 includes an outlet pipe 30 through which the discharge line 5 discharges into the atmosphere, i.e., to the outside of the treatment loop 4 and the treatment system 1.

[0102] In addition to the guide line 3 and discharge line 5 used in the first adsorption configuration of the drying unit 14, the processing circuit 4 also includes a tube that allows the implementation of the second desorption configuration of the drying unit 14. The processing circuit 4 includes a sampling line 32 for regenerating the drying unit 14 and a sampling conduit 34 for cooling the drying unit 14.

[0103] Sampling line 32 is connected to discharge line 5 in the region where the decarbonized exhaust gas it delivers has a temperature above 180°C, corresponding to the first portion of the decarbonized exhaust gas. This temperature is optimal for the dryer 16 in the regeneration drying unit 14. Sampling conduit 34 is connected to exhaust line 5 in the region where the decarbonized exhaust gas it delivers has a temperature of approximately 5°C, corresponding to the second portion of the decarbonized exhaust gas. This 5°C temperature is suitable for cooling the dryer 16 after regeneration in the drying unit 14. It should be noted that this connection of sampling line 32 and sampling conduit 34 varies according to different embodiments of the invention.

[0104] Processing system 1 in Figure 1 In the first embodiment, in Figure 2 In the second embodiment and in Figure 3 The third embodiment is shown. The first and second embodiments correspond to low-pressure treatment system 1 and high-pressure treatment system 1, respectively. These first and second embodiments are suitable for, but not limited to, situations where the flow rate of decarbonized exhaust gas is greater than 50% of the total exhaust gas leaving fuel consumer 2. In contrast, the third embodiment is a water injection treatment system 1. This third embodiment is suitable for situations where the flow rate of decarbonized exhaust gas is less than 50% of the total exhaust gas leaving fuel consumer 2.

[0105] exist Figure 1 In the first embodiment shown, a sampling line 32 through which a first portion of the decarbonized exhaust gas flows is connected to the discharge line 5 between the second turbine 28 and the outlet pipe 30. This sampling line 32 also leads to the drying unit 14. Within the sampling line 32 of the first embodiment, the first portion of the decarbonized exhaust gas has an absolute pressure of approximately 1.1 bar. More generally, the first portion of the decarbonized exhaust gas has a pressure between 1 and 1.3 bar absolute pressure.

[0106] In this first embodiment, the processing loop 4 includes an outlet conduit 38 dedicated to discharging a first portion of the decarbonized exhaust gas from the processing system 1. Figure 1 The outlet duct 38, visible in the diagram, connects the drying unit 14 to the atmosphere. For this purpose, it can be connected to the outlet pipe 30, through which the first portion of the decarbonized exhaust gas passes and is then released into the atmosphere. Alternatively, the outlet duct 38 can be a separate duct leading to the atmosphere. Near the drying unit 14, the outlet duct 38 is equipped with a pilot valve 40, which allows the first portion of the decarbonized exhaust gas to enter the outlet duct 38 when open and prevents this passage when closed.

[0107] exist Figure 2In the second embodiment shown, a sampling line 32 for delivering a first portion of the decarbonized exhaust gas is connected to an outlet line 5 between a first pass 8 of the heat exchanger 6 and a first turbine 26, and leads to the drying unit 14. In this sampling line 32 of the second embodiment, the first portion of the decarbonized exhaust gas has a pressure of approximately 4 bar absolute value. More generally, the first portion of the decarbonized exhaust gas has a pressure between 3 and 5 bar absolute pressure.

[0108] exist Figure 3 In the third embodiment shown, the discharge line 5 includes a water injection point 36 at which water is injected into the treatment circuit 2 to humidify the decarbonized exhaust gas. More specifically, the water injection point 36 is located between the compressor 12 and the first pass 8 of the heat exchanger 6. In the third embodiment, a sampling line 32 through which the first portion of the decarbonized exhaust gas flows is connected to the discharge line 5 between the compressor 12 and the water injection point 36; in other words, upstream of the water injection point 36, and leading to the drying unit 14. Within the sampling line 32 of this third embodiment, the first portion of the decarbonized exhaust gas has an absolute pressure of approximately 4 bar, i.e., between 3 bar and 5 bar.

[0109] In the second and third embodiments, the processing system 1 does not have an outlet conduit 38 as in the first embodiment. Instead, in both embodiments, a first portion of the decarbonized exhaust gas is configured to be reinjected into the processing loop 4. For this purpose, the processing loop 4 includes a return conduit 42 that returns the first portion of the decarbonized exhaust gas, which has already participated in the regeneration of the drying unit 14, back to the processing loop 4. In the second and third embodiments, the return conduit 42 connects the drying unit 14 between the first pass 8 of the heat exchanger 6 and the first turbine 26 to the discharge line 5. More specifically, in the second embodiment, the return conduit 42 is connected between the sampling line 32 and the first turbine 26. To facilitate the flow of the decarbonized exhaust gas within a portion of the discharge line 5 arranged between the first pass 8 of the heat exchanger 6 and the first turbine 26, the discharge line 5 is equipped with a flow regulating valve 44, which is arranged between the connection point of one side of the sampling line 32 and the connection point of the other side of the return conduit 42.

[0110] Furthermore, in this second embodiment, the return duct 42 is equipped with a control valve 46, which, when open, allows a first portion of the decarbonized exhaust gas to enter the return duct 42, and when closed, prevents any such passage.

[0111] Regardless of the embodiment, sampling line 32 includes a control valve 48 or a segmented valve that, when open, allows a first portion of the decarbonized exhaust gas to enter sampling line 32 for regeneration of drying unit 14, and prevents such passage when closed. In a first embodiment, sampling line 32 also includes a flow control valve 49.

[0112] As previously described, sampling conduit 34 serves to guide a second portion of the decarbonized exhaust gas to drying unit 14 for cooling. Sampling conduit 34 is connected to discharge line 5 in the region where the decarbonized exhaust gas it delivers has a temperature of approximately 5°C. In all three embodiments, sampling conduit 34 thus connects the outlet of compressor 12 to drying unit 14. As shown, sampling conduit 34 may have a portion merged with sampling line 32 dedicated to regeneration. Since cooling and regeneration do not occur simultaneously but sequentially, this allows the decarbonized exhaust gas to utilize a portion of processing loop 4 that would otherwise be unused. Sampling conduit 34 is provided with control valve 50, which, when open, allows the second portion of the decarbonized exhaust gas to pass through to cool drying unit 14, and when closed, prevents this passage.

[0113] In the second and third embodiments, the return duct 42, which allows the first portion of the decarbonized exhaust gas to be re-injected, is also used by the second portion of the decarbonized exhaust gas. In other words, the return duct 42 is shared for both the decarbonized exhaust gas used for regenerating the drying unit 14 and the decarbonized exhaust gas used for cooling the drying unit 14.

[0114] Conversely, in the first embodiment, the processing loop 4 includes a return conduit 42 specifically designed to guide a second portion of the decarbonized exhaust gas, the first portion of which passes through the outlet conduit 30. In this first embodiment, as... Figure 1 As shown, the return conduit 42 connects the drying unit 14 to the first pass 8 of the heat exchanger 6.

[0115] In all embodiments, the processing system 1 includes a system 52 for controlling the flow of exhaust gas within the processing loop 4. This control system 52 is capable of controlling the opening and closing of various valves in the processing system 1 to implement the first adsorption configuration and the second desorption configuration of the drying unit 14, and more specifically, its regeneration or cooling.

[0116] The processing system 1 is configured to implement the exhaust gas treatment method according to the invention, and will now be described with respect to each embodiment.

[0117] Processing method 1 begins with a first step or cooling step, wherein exhaust gas from fuel consumer 2 is routed from fuel consumer 2 to heat exchanger 6 via feed line 3. This first cooling step is performed by implementing a heat exchange step within heat exchanger 6, wherein the first heat exchange step operates between exhaust gas from fuel consumer 2 and decarbonized exhaust gas flowing in a first pass 8, and a second heat exchange step operates between exhaust gas from fuel consumer 2 and decarbonized exhaust gas flowing in a second pass 10.

[0118] Following the first step, the processing method includes a second step or a compression step, wherein the cooled exhaust gas is compressed within the compression device 12. Once compressed, the exhaust gas is directed by the guide line 3 to the drying unit 14 to perform a third step or a drying step. The compressed exhaust gas then passes through one or more dryers 16 in their first adsorption configuration, i.e., for the embodiment shown here, a first dryer 16A and a second dryer 16B.

[0119] During the fourth step, or carbon dioxide capture step, the dried exhaust gas passes through the first sub-unit 22 and the second sub-unit 24 of the carbon dioxide capture device 20, where it is decarbonized and cooled to a cryogenic temperature. In the fourth step, the dried exhaust gas is cooled to a cryogenic temperature.

[0120] Once the exhaust gas has been decarbonized, it travels along the discharge line 5. The treatment method includes a reheating step during which the decarbonized exhaust gas flowing in the discharge line 5 passes through the compression unit 12. It is then reheated by exchanging heat with the exhaust gas flowing through the compression unit 12 before being dried in the drying unit 14.

[0121] When the processing method is implemented in the processing system 1 according to the third embodiment, the processing method includes a humidification step, which corresponds to injecting water into the processing loop 4, and more precisely, into the discharge line 5, to humidify the decarbonized exhaust gas flowing therethrough. This humidification step is performed after the reheating step. The first and second embodiments do not include such a humidification step.

[0122] Following the reheating step, or the humidification step in an embodiment of which this step is implemented, the decarbonized exhaust gas participates in the first and second heat exchange steps as described above. It should be noted that between these two heat exchange steps, the treatment method includes the occurrence of a first energy generation step, during which the decarbonized exhaust gas passes through the first turbine 26. A further energy generation step, in this case a second energy generation step, is performed after the second heat exchange step. During this second energy generation step, the decarbonized exhaust gas flows through the second turbine 28. After this second energy generation step, the decarbonized exhaust gas is discharged from the treatment system 1 through a release step, in which it enters the atmosphere through the outlet pipe 30.

[0123] The above description of the processing method according to the invention applies when one of the drying units 14, or more specifically one of its dryers 16, is in its first adsorption configuration. The processing method also includes steps for implementing a second desorption configuration, which will now be described in detail.

[0124] The second desorption structure of the drying unit 14 requires the successive implementation of a regeneration step and a cooling step, which correspond to the sixth and eighth steps of the treatment method, respectively. Each of these sixth and eighth steps requires the supply of decarbonized exhaust gas within the drying unit 14, which is carried out during the fifth step for the regeneration step and the seventh step for the cooling step, respectively.

[0125] The fifth step is the sampling step, during which a first portion of the decarbonized exhaust gas is sampled at a first point in the processing loop, which varies depending on the embodiment, wherein the temperature of these decarbonized exhaust gases is between 35 and 250°C.

[0126] As previously mentioned Figure 1 As described in the processing system 1, in the first embodiment, the sampling point for the first portion of the decarbonized exhaust gas is located within the processing loop 4 between the second turbine 28 and the outlet pipe 30. It should be understood that in this first embodiment, the fifth step is therefore performed after the flow of the decarbonized exhaust gas and after the second energy generation step.

[0127] Once sampled, the first portion of the decarbonized exhaust gas is then sent to the drying unit 14 via sampling line 32. This first portion of the decarbonized exhaust gas regenerates one or more dryers 16 of the drying unit 14 during the sixth step, and is then returned to the atmosphere via outlet duct 38 and then outlet pipe 30 during the release step.

[0128] In the case of the second embodiment of processing system 1, that is, regarding Figure 2The fifth step, which samples the first portion of the decarbonized exhaust gas, occurs between the heat exchanger 6 and the first turbine 26; in other words, it occurs between the first heat exchange step and the first energy generation step, depending on the flow of the decarbonized exhaust gas.

[0129] Once sampled, the first portion of the decarbonized exhaust gas is then sent to the drying unit 14 via sampling line 32. This first portion of the decarbonized exhaust gas regenerates one or more dryers 16 of the drying unit 14 during the sixth step, and is then reinjected into the processing loop 4 during the return step. More specifically, it is reinjected between the point where the first portion of the decarbonized exhaust gas is sampled and the first turbine 26, i.e., according to the flow of the decarbonized exhaust gas between the first heat exchange step and the first energy generation step.

[0130] Finally, Figure 3 In the third embodiment shown, the fifth step of sampling the first portion of the decarbonized exhaust gas occurs between the compression device 12 and the water injection point 36, i.e., based on the flow of the decarbonized exhaust gas between the reheating step and the humidification step.

[0131] Once sampled, a first portion of the decarbonized exhaust gas is then sent to the drying unit 14 via sampling line 32. This first portion of the decarbonized exhaust gas regenerates one or more dryers 16 of the drying unit 14 during a sixth step, and is then re-injected into the processing loop 4 during a return step. More specifically, it is re-injected between the first pass 8 of the heat exchanger 6 and the first turbine 26, i.e., according to the flow of the decarbonized exhaust gas between the first heat exchange step and the first energy generation step, as in the second embodiment.

[0132] The seventh step is a sampling step, during which a second portion of the decarbonized exhaust gas is sampled at a second point in the processing loop via sampling conduit 34, at a temperature of approximately 5°C. Similar to all three embodiments, this second sampling point is located on the processing loop 4 at the outlet of the compression unit 12, i.e., according to the flow of the decarbonized exhaust gas after the first reheating step.

[0133] The second portion of the exhaust gas sampled during the seventh step is directed to the drying unit 14, where the dryer 16 is cooled during the eighth cooling step.

[0134] At the end of the eighth cooling step, a second portion of the decarbonized exhaust gas is reinjected into the processing loop 4 via return duct 42 at a point that varies depending on the embodiment. In the first embodiment, the second portion of the decarbonized exhaust gas is reinjected upstream of the heat exchanger 6, i.e., before the first heat exchange step according to the flow of the decarbonized exhaust gas.

[0135] In the second and third embodiments, the re-injection of the second portion of the decarbonized exhaust gas occurs between the first pass 8 of the heat exchanger 6 and the first turbine 26, i.e., according to the flow of the decarbonized exhaust gas between the first heat exchange step and the first energy generation step.

[0136] It should be noted that, regardless of the embodiment chosen, the implementation of the processing method is supervised by a control method implemented by the control system 52, which, for example, determines the alternation between the first adsorption structure and its second desorption structure of the drying unit 14, and for the second desorption structure, determines the alternation between the regeneration stage and the cooling stage, these alternations being controlled by the opening or closing of various valves in the processing loop 4 of the processing system 1.

[0137] Therefore, the present invention proposes a treatment method and system for treating exhaust gas from fuel consumers, which limits the number of components required to operate the drying unit of the treatment system by avoiding the need for cold gas, which would otherwise be used exclusively to cool the drying unit.

[0138] However, the invention is not limited to the devices and constructions described and illustrated herein, but extends to any equivalent devices and constructions, and any technically operable combinations thereof.

Claims

1. A method for treating a carbon dioxide-containing gas emitted from an emission source (2), comprising, during the flow of the carbon dioxide-containing gas within a treatment loop (4): In the first step, during the first step, the gas containing carbon dioxide is cooled in a heat exchanger (6); The second step involves compressing the cooled gas containing carbon dioxide within the compression device (12). The third step involves drying the compressed gas containing carbon dioxide within the drying unit (14). In the fourth step, carbon dioxide is removed from the dried carbon dioxide-containing gas in the carbon dioxide capture device (20) to produce decarbonized gas. In the fifth step, during the fifth step, a first portion of the decarbonized gas is sampled from a first point in the processing loop (4), at which the temperature of the decarbonized gas is above 180°C, and the first portion of the decarbonized gas is sent to the drying unit (14). In the sixth step, during which a first portion of the decarbonized gas regenerates the drying unit (14); In the seventh step, during the seventh step, a second portion of the decarbonized gas is sampled from a second point in the processing loop (4), at which the temperature of the decarbonized gas is approximately 5°C, and the second portion of the decarbonized gas is sent to the drying unit (14). In the eighth step, a second portion of the decarbonized gas is cooled in the regenerated drying unit (14).

2. The processing method according to claim 1, comprising a first heat exchange step and a second heat exchange step, wherein during the first heat exchange step and the second heat exchange step, the decarbonized gas passes through the heat exchanger (6) to cool the carbon dioxide-containing gas emitted from the emission source (2).

3. The processing method according to claim 2, wherein a first energy generation step is included between the first heat exchange step and the second heat exchange step, during which the decarbonized gas passes through the first turbine (26) of the processing loop (4).

4. The processing method according to claim 3, comprising a second energy generation step after the second heat exchange step, wherein during the second energy generation step, the decarbonized gas passes through the second turbine (28) of the processing loop (4).

5. The processing method according to any one of the preceding claims in conjunction with claim 3, wherein, The fifth step occurs between the first heat exchange step and the first energy generation step.

6. The processing method according to claim 4, wherein, The fifth step occurs after the second energy generation step.

7. The processing method according to any one of claims 1 to 4, comprising a humidification step of humidifying the decarbonized gas by injecting water into the processing circuit (4), wherein the fifth step occurs prior to the humidification step.

8. The processing method according to claim 7 in combination with any one of claims 3 and 4, wherein, The humidification step occurs before the first heat exchange step.

9. The processing method according to any one of the preceding claims, comprising, after the sixth step, releasing a first portion of the decarbonized gas into the atmosphere.

10. The processing method according to any one of claims 1 to 8 in conjunction with claim 3, after the sixth step, includes the step of returning a first portion of the decarbonized gas to a point in the processing loop (4) located between the heat exchanger (6) and the first turbine (26).

11. The processing method according to any one of the preceding claims, comprising a reheating step after the fourth step, during which the decarbonized gas passes through the compression device (12).

12. The processing method according to claim 11, after the eighth step, includes the step of returning a second portion of the decarbonized gas to a point in the processing loop (4) located between the compression device (12) and the heat exchanger (6).

13. The processing method according to any one of claims 1 to 11, comprising, after the eighth step, returning a second portion of the decarbonized gas to a point in the processing loop (4) located between the heat exchanger (6) and the first turbine (26).

14. The processing method according to any one of the preceding claims, wherein, The execution of the fifth step and the seventh step depends on the method used to control the state of the drying unit (14).

15. A processing system (1) configured to implement the processing method according to any one of the preceding claims, the processing system (1) comprising a processing loop (4) for processing a gas containing carbon dioxide, wherein the heat exchanger (6), the compression device (12), the drying unit (14) and the carbon dioxide capture device (20) are arranged sequentially on the processing loop (4).

16. The processing system (1) according to claim 15, wherein, The drying unit (14) is configured to alternately exhibit a first adsorption structure and a second desorption structure.

17. The processing system (1) according to any one of claims 15 and 16, wherein, The processing circuit (4) includes a sampling line (32) dedicated to guiding a first portion of the decarbonized gas to the drying unit (14), and a sampling conduit (34) dedicated to guiding a second portion of the decarbonized gas to the drying unit (14).

18. The processing system (1) according to the preceding claim, wherein, The processing circuit (4) includes a control valve (48) and / or a segment valve for the sampling line (32) and a control valve (50) for controlling the sampling conduit (34).

19. The processing system (1) according to any one of claims 15 to 18 in combination with claim 4, wherein, The heat exchanger (6) includes at least a first pass (8) and a second pass (10), the first turbine (26) is located on the processing loop (4) between the first pass (8) and the second pass (10) of the heat exchanger (6), and the second turbine (28) connects the second pass (10) of the heat exchanger (6) to the outlet pipe (30) of the processing loop (4).

20. The processing system (1) according to any one of claims 15 to 19, wherein, The processing circuit (4) includes an outlet conduit (38) dedicated to discharging a first portion of the decarbonized gas from the drying unit (14) into the atmosphere.

21. The processing system (1) according to any one of claims 15 to 20, wherein, The processing circuit (4) includes a return conduit (42) dedicated to discharging a first portion and / or a second portion of the decarbonized gas from the drying unit (14).

22. The processing system (1) according to any one of claims 15 to 21, comprising a control system (52) for controlling the flow of carbon dioxide-containing gas within the processing loop (4).

23. The processing system (1) according to claim 22, wherein, The control performed by the control system (52) depends on the flow rate of the carbon dioxide-containing gas in the processing loop (4).

24. The processing system (1) according to claim 16, wherein, The drying unit (14) includes a plurality of dryers (16), the plurality of dryers (16) including at least a first dryer (16A) and a second dryer (16B), wherein when the second dryer (16B) is in the second desorption configuration, the first dryer (16A) is in the first adsorption configuration.

25. A floating structure comprising an emission source (2) for discharging a gas containing carbon dioxide and a treatment system (1) for treating the gas containing carbon dioxide emitted from the emission source (2) according to any one of claims 15 to 24.

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