Carbon dioxide-laden gas cooling system

Abstract

Title: Carbon Dioxide Gas Cooling System Carbon dioxide gas cooling system comprising a first circuit configured to be traversed by the carbon dioxide gas and a second circuit configured to be traversed by a decarbonized gas, said system comprising at least one heat exchange zone between the first circuit and the second circuit, said zone comprising at least one heat exchanger configured to operate a heat exchange between the carbon dioxide gas and the decarbonized gas, the cooling system comprising a third circuit configured to be traversed by a heat transfer fluid and which includes at least one heat exchanger configured to vaporize said heat transfer fluid by heat exchange with the carbon dioxide gas, said heat exchanger being disposed in the heat exchange zone, the third circuit being connected to the second circuit.Figure from the summary: figure 1.

Description

Title of the invention: System for cooling a gas loaded with carbon dioxide

[0001] The present invention relates to the field of treatment of gas loaded with carbon dioxide and more particularly concerns a system for cooling said gas loaded with carbon dioxide.

[0002] When a source of carbon dioxide-laden gas emission is in operation, for example an internal combustion engine of a vehicle such as a floating structure, carbon dioxide-laden gases are generated. These gases are generally released into the atmosphere, causing environmental damage, in particular because of the carbon dioxide they contain.

[0003] In addition to the ecological impact, this release into the atmosphere is a loss of energy because carbon dioxide has multiple interests in various technical fields and can, for example, serve as a cooling medium in a gas treatment system.

[0004] It may then be appropriate to treat the carbon dioxide-laden gases from a gas emission source in order to extract the carbon dioxide therefrom with a view to exploiting it for subsequent use or marketing. However, a system for cooling a carbon dioxide-laden gas does not currently make it possible to use all of the heat available in the carbon dioxide-laden gas fumes. The systems known to date are not optimized and this is one of the reasons why these systems must be improved.

[0005] The present invention makes it possible to overcome these drawbacks by proposing a system for cooling a flow of gas loaded with carbon dioxide comprising a first circuit configured to be traversed by the flow of gas loaded with carbon dioxide and a second circuit configured to be traversed by a flow of decarbonized gas, said system comprising at least one heat exchange zone between the first circuit and the second circuit, said zone comprising at least one heat exchanger configured to carry out a heat exchange between the flow of gas loaded with carbon dioxide and the flow of decarbonized gas, the cooling system comprising a third circuit configured to be traversed by a heat transfer fluid and which comprises at least one heat exchanger configured to vaporize said heat transfer fluid by heat exchange with the flow of gas loaded with carbon dioxide, said heat exchanger being arranged in the heat exchange zone,the third circuit being connected to the second circuit.

[0006] The purpose of the cooling system according to the invention is to recover the calories present within a flow of gas loaded with carbon dioxide emitted by an emission source. It is noted that, in the systems of the prior art, this energy in the form of calories is not used. The emission source may consist of a heat engine for example, which makes the temperature of the flow of gas loaded with carbon dioxide high. This is only an example, the emission source covering any device which releases a flow of hot gas loaded with carbon dioxide.

[0007] The recovered heat makes it possible to reduce the specific consumption of the device for treating the gas flow loaded with carbon dioxide by around 25% and also makes it possible to reduce the overconsumption of the emission source when it is associated with this treatment device. The injection of the heat transfer fluid, previously evaporated by heat exchange with the gas flow loaded with carbon dioxide, into the decarbonized gas flow makes it possible to lower the temperature of this decarbonized gas flow sent to one or more turbines. The work then carried out by this turbine has a significantly improved efficiency.

[0008] To recover this heat, the cooling system comprises at least one heat exchanger configured to carry out a heat exchange between the flow of gas loaded with carbon dioxide circulating in the first circuit and the heat transfer fluid circulating in the third circuit, the heat transfer fluid being configured to recover the calories present in the flow of gas loaded with carbon dioxide. The invention chooses to use a maximum of calories present in the flow of gas loaded with carbon dioxide. More precisely, the heat exchanger comprises a first pass crossed by the flow of gas loaded with carbon dioxide circulating in the first circuit and a second pass crossed by the heat transfer fluid circulating in the third circuit, the first pass and the second pass being close to each other so that the heat present in the flow of gas loaded with carbon dioxide leads to evaporation of the heat transfer fluid.

[0009] The third circuit then directs the heat transfer fluid having recovered the calories within the flow of gas loaded with carbon dioxide to a heat exchange zone. This heat exchange zone is for example a chamber in which heat exchanges occur, in particular between the flow of gas loaded with carbon dioxide coming from the emission source and the heat transfer fluid. Upon contact with the flow of gas loaded with carbon dioxide present in the thermal zone, the heat transfer fluid vaporizes within the heat exchanger. The third circuit comprises a section in which the vaporized heat transfer fluid circulates to the second circuit in which the flow of decarbonized gas circulates so that the heat transfer fluid / flow of decarbonized gas mixture increases the mass of gas to be expanded and consequently optimizes the energy performance of the system.

[0010] According to another characteristic, at least one device for compressing the gas flow loaded with carbon dioxide is arranged on the first circuit. Advantageously, the compression device is arranged downstream of the heat exchange zone. In addition, an expansion device can be arranged upstream of the heat exchange zone.

[0011] The compression device is configured to raise the pressure of the carbon dioxide-laden gas stream.

[0012] According to another characteristic, the heat exchanger configured to vaporize the heat transfer fluid by heat exchange with the flow of gas loaded with carbon dioxide is a first heat exchanger, the third circuit comprising a second heat exchanger configured to carry out a heat exchange between the flow of gas loaded with carbon dioxide and the heat transfer fluid, said second heat exchanger being arranged on the first circuit, downstream of the compression device, in particular a first compression device.

[0013] The first and second heat exchangers each comprise a first pass and a second pass, the first pass of which is crossed by the flow of gas loaded with carbon dioxide and the second pass of which is crossed by the heat transfer fluid. Thus, said heat exchangers are configured to carry out a heat exchange between said flows making it possible on the one hand to lower the temperature of the flow of gas loaded with carbon dioxide intended to pass through a carbon dioxide capture system in order to generate a flow of decarbonized gas, and on the other hand to recover the heat present in said gas loaded with carbon dioxide.

[0014] According to another characteristic, the heat transfer fluid comprises mainly water. For example, the heat transfer fluid comprises at least 50% by volume of water, preferably at least 75% by volume of water and even more preferably at least 90% by volume of water. According to one aspect, the heat transfer fluid is exclusively water. The water may come from the cooling system according to the invention, which avoids the installation of storage means. The water may also come from a member external to the cooling system according to the invention. In all cases, the advantage of water is that it is available at low cost and is non-polluting, which allows it to be discharged into the environment, if necessary.

[0015] According to another characteristic, the cooling system comprises at least one separator configured to collect the heat transfer fluid present within the flow of gas loaded with carbon dioxide. The water present in the flow of gas loaded with carbon dioxide tends to condense within the separator, which makes it possible to recover the water in the liquid state in a lower portion of said separator.

[0016] According to another characteristic, the third circuit comprises a device for softening the heat transfer fluid. The softening device is configured to separate and / or extract from the heat transfer fluid the acid gases present therein, thus limiting the risk of corrosion for the components which are crossed by this heat transfer fluid.

[0017] According to another characteristic, the system comprises a plurality of separators configured to collect the heat transfer fluid present within the flow of gas loaded with carbon dioxide, said separators being connected to the softening device.

[0018] Each separator is arranged upstream of a compression device to ensure that the flow sent to said compression device is free of a liquid phase. For this purpose, the third circuit comprises several branches for circulating the heat transfer fluid extracted from the flow of gas loaded with carbon dioxide which extend from each separator and to the softening device. The invention thus makes it possible to collect the heat transfer fluid at various locations in the cooling system according to the invention.

[0019] According to another characteristic, the second circuit comprises a device for recovering energy generated by the flow of decarbonized gas, the connection of the third circuit to the second circuit being made between an outlet of the heat exchanger and an inlet of the energy recovery device. The injection of the heat transfer fluid takes place outside the heat exchange zone, downstream of the latter, but before entering the energy recovery device.

[0020] The energy recovery device is composed of a turbine associated with a generator, for example an electric generator. It is understood that said recovery device is arranged downstream of the heat exchanger, according to the direction of circulation of the flow of decarbonized gas within the second circuit.

[0021] According to another characteristic, the heat exchange zone comprises a chamber intended to be traversed by the flow of gas loaded with carbon dioxide, the heat exchanger and the heat exchanger extending within the chamber.

[0022] The invention also covers a device for treating a gas flow loaded with carbon dioxide comprising a cooling system as described in the present document and a system for capturing the carbon dioxide present in the gas flow loaded with carbon dioxide, the capture system being configured to extract at least part of the carbon dioxide and return the decarbonized gas flow to the cooling system.

[0023] The invention also covers a method for cooling a gas flow loaded with carbon dioxide using a cooling system as described in the present document, during which the heat transfer fluid is evaporated by heat exchange with the gas flow loaded with carbon dioxide and during which the evaporated heat transfer fluid is injected into the decarbonized gas flow.

[0024] According to an optional characteristic of this process, the flow of decarbonized gas is saturated with heat transfer fluid before it enters the heat exchanger.

[0025] Other characteristics, details and advantages of the invention will emerge more clearly on reading the description of a detailed embodiment which follows, given for informational and non-limiting purposes with reference to the appended schematic drawings, in which:

[0026] [Fig-1] schematically represents a system for cooling a charged gas in carbon dioxide according to the invention;

[0027] [Fig.2] represents an embodiment of the system for cooling a gas loaded with carbon dioxide according to the invention;

[0028] [Fig.3] schematically represents the operation of the cooling system of [Fig.2].

[0029] The features, variants and the different embodiments of the invention, as they have been described or as they will be presented in the detailed description which follows, can be associated with each other, in various combinations, to the extent that they are not incompatible or mutually exclusive. In particular, variants of the invention may be imagined comprising only a selection of features described below in isolation from the other features described, if this selection of features is sufficient to confer a technical advantage and / or to differentiate the invention from the prior art.

[0030] This document uses the words "upstream" and "downstream" to define the relative arrangement of the components. These words are assessed according to the direction of circulation of the fluid which passes through said components or which circulates within the circuit concerned.

[0031] [Fig.l] illustrates a device 1 for treating a gas flow loaded with carbon dioxide 2 according to the invention which is configured to recover the treated carbon dioxide in order to reuse it in subsequent applications.

[0032] Such a treatment device 1 comprises a system 4 for capturing and a system 6 for cooling the carbon dioxide present in the flow of gas loaded with carbon dioxide 2.

[0033] The capture system 4 is configured to extract at least part of the carbon dioxide, thus generating a decarbonized gas flow 8. In other words, the capture system 4 according to the invention makes it possible to produce a decarbonized gas flow 8 after capturing the carbon dioxide contained in the combustion gas flow loaded with carbon dioxide 2.

[0034] This flow of decarbonized gas 8 is subsequently directed towards the cooling system 6 in order to increase the overall energy performance of the treatment device 1 as will be detailed in light of the description below. Indeed, the flow of decarbonized gas 8 reaches the cooling system 6 at a pressure greater than 4 bars (i.e. 4*105 Pa). It is therefore possible to implement an expansion of this flow of decarbonized gas 8, the efficiency of such expansion being improved by the injection of heat transfer fluid. It is understood here that the capture system 4 and the cooling system 6 operate together to fulfill the overall function of the treatment device 1.

[0035] Such a treatment device 1 may for example be integrated within a vehicle, at the outlet of a chimney, a factory or any other entity comprising an emission source 10 of gas loaded with carbon dioxide. The emission source 10 may for example be an internal combustion engine such as an engine providing propulsion for a vehicle or the engine of an electric generator of said vehicle, for example a floating structure.

[0036] When the emission source 10 is in operation, it emits gases comprising carbon dioxide, in other words, a flow loaded with carbon dioxide 2. The capture system 4 thus makes it possible to capture the carbon dioxide present within the flow loaded with carbon dioxide 2 in order to reuse it, instead of releasing it directly into the atmosphere, at the risk of polluting the environment.

[0037] In order to treat the flow of gas loaded with carbon dioxide 2, it circulates from the emission source 10 to the capture system 4 via a first circuit 12. Before reaching the capture system 4, the flow of gas loaded with carbon dioxide 2 is expanded by an expansion device 14 in order to reach a pressure of approximately 1.04 bar absolute, such an expansion device 14 being in particular an exhaust turbine of a turbocharger of an internal combustion engine, the latter forming the emission source 10. It may be noted that the expansion device 14 is optional and its presence depends in particular on the type of the emission source 10. Thus, the flow of gas loaded with carbon dioxide coming from the emission source 10 may not undergo expansion.In other words, within the framework of the invention, the pressure of the flow of this gas is indifferent, one can very well consider such a flow of gas from an emission source 10 and treat it at a pressure greater than 1.04 bar. In the example cited above, a pressure of 1.04 bar is used which corresponds to the outlet pressure of the exhaust gases from the ship's engine.

[0038] At the outlet of the expansion device 14, the flow of gas loaded with carbon dioxide 2 emitted by the emission source 10 passes through a heat exchange zone 16 delimited by a chamber 18 which can for example be defined as a closed internal space, which has an inlet and an outlet each used by the flow of gas loaded with carbon dioxide 2.

[0039] The chamber 18 houses a first heat exchanger 20 and a first heat exchanger 22. Optionally, the chamber 18 also houses a second heat exchanger 24.

[0040] The first heat exchanger 20 is arranged upstream of the first heat exchanger 22 which is itself arranged upstream of the second heat exchanger 24, according to the direction of circulation of the flow of gas loaded with carbon dioxide 2 within the heat exchange zone 16.

[0041] Alternatively, tubes of the first heat exchanger 20, the first heat exchanger 22 and / or the second heat exchanger 24 may be arranged in parallel with each other.

[0042] At the outlet of the heat exchange zone 16, the flow of gas loaded with carbon dioxide 2 joins a compression unit 7 whose role is to raise the pressure of the gas loaded with carbon dioxide 2, cool it and possibly ensure separation of certain products present in these gases loaded with carbon dioxide 2.

[0043] As illustrated in [Fig.l], such a compression unit 7 comprises a first inlet which receives the gas loaded with carbon dioxide 2 from the heat exchange zone 16, a second inlet connected to the capture system 4 and through which the decarbonized gas 8 enters the compression unit 7 and a third inlet through which the heat transfer fluid enters the compression unit 7.

[0044] The compression unit 7 also comprises outlets, among which there is a first outlet for decarbonized gas 8, a second outlet for gas loaded with carbon dioxide 2, and a third, a fourth, a fifth and a sixth outlet for heat transfer fluid.

[0045] [Fig.2] illustrates in detail the constitution of such a compression unit 7.

[0046] The flow of gas loaded with carbon dioxide 2 circulating in the first circuit 12 passes through at least one separator, possibly a plurality of separators among which there is a first separator 26 and a second separator 28 configured to separate a heat transfer fluid 30 from said flow of gas loaded with carbon dioxide 2. The second separator 28 is arranged within the first circuit 12 downstream of the first separator 26.

[0047] The role of the separator(s) is in particular to collect the heat transfer fluid 30. This heat transfer fluid 30 is water and it is configured to recover the calories present in the flow of gas loaded with carbon dioxide 2 by heat exchange within heat exchangers 36, 38. In the invention, the heat transfer fluid 30 circulates in a third circuit 54. The heat transfer fluid 30 recovered in the separator 26, 28 must be degassed at atmospheric pressure before it can be taken up by a pump 60.

[0048] Furthermore, the flow of gas loaded with carbon dioxide 2 passes through several compression devices, more particularly a first compression device 32 and a second compression device 34 arranged on the first circuit 12 and configured to raise the pressure of the gas of the flow loaded with carbon dioxide 2. The pressure at the outlet of the first compression device 32 is for example equal to 5.4 bars absolute.

[0049] The second compression device 34 is arranged downstream of the first compression device 32. More precisely, the first compression device 32 is arranged downstream of the first separator 26 and the second compression device 34 is arranged downstream of the second separator 28.

[0050] The flow of gas loaded with carbon dioxide 2 leaving the first compression device 32 passes through a second heat exchanger 36, the latter carrying out a heat exchange between the flow of gas loaded with carbon dioxide and compressed by the first compression device 32 and the heat transfer fluid 30. The flow of gas loaded with carbon dioxide 2 leaving the second compression device 34 passes through a third heat exchanger 38, the latter carrying out a heat exchange between the flow of gas loaded with carbon dioxide 2 and compressed by the second compression device 34 and the heat transfer fluid 30.

[0051] The flow of gas loaded with carbon dioxide 2 leaving the third heat exchanger 38 is subsequently directed towards a third heat exchanger 40 before reaching the capture system 4 in order to produce the flow of decarbonized gas 8.

[0052] Figures 2 and 3 show the existence of two separators referenced 26 and 28 each arranged upstream of a compression device 32, 34. Interestingly, the invention can comprise another separator arranged downstream of the third heat exchanger 38. It is also possible to provide an additional separator arranged downstream of the third heat exchanger 40. These additional separators recover the heat transfer fluid with a view to using it within the system according to the invention.

[0053] The flow of decarbonized gas 8 passes through a second circuit 42 of the cooling system 6 according to the invention. The second circuit 42 channels the flow of decarbonized gas 8 to the third heat exchanger 40 and it is then understood that the third heat exchanger 40 carries out a heat exchange between the flow of gas loaded with carbon dioxide 2 circulating in the first circuit 12 and the flow of decarbonized gas 8 circulating in the second circuit 42. The flow of decarbonized gas 8 is subsequently conveyed to a fourth heat exchanger 44 which carries out a heat exchange between the flow of decarbonized gas 8 upstream of the heat exchange zone 16 and the same flow of decarbonized gas 8 downstream of the heat exchange zone 16.

[0054] The second circuit 42 channels the flow of decarbonized gas 8 towards the first heat exchanger 22, in particular via the branch referenced 42b, then possibly towards the second heat exchanger 24.

[0055] After passing through the first heat exchanger 22, the decarbonized gas flow 8 passes through a first energy recovery device 50, just as after passing through the second heat exchanger 24, the decarbonized gas flow 8 passes through a second energy recovery device 52. The recovery devices energy 50, 52 consist of a turbine which operates an expansion of the decarbonized gas flow 8. Such a turbine can constitute a drive turbine which directly supplies mechanical energy to the first or second compression device 32, 34. Alternatively, this turbine can be associated with an electric generator so as to transform the mechanical energy of the turbine into electrical energy.

[0056] At the outlet of the second energy recovery device 52, the second circuit 42 conducts the flow of decarbonized gas 8 towards the fourth heat exchanger 44, then towards a third separator 46, in order to reach a management member 48 in order to be able to be recycled or reused or released into the atmosphere.

[0057] It is understood here that the heat exchange zone 16 is an enclosure where a heat exchange takes place between the flow of gas loaded with carbon dioxide 2 coming from the emission source 10 and the flow of decarbonized gas 8 alone or a mixture of this flow of decarbonized gas 8 and heat transfer fluid 30, by means of the heat exchanger 20 and the heat exchanger 22.

[0058] The heat transfer fluid 30 extracted from the flow of gas loaded with carbon dioxide 2 circulates in the third circuit 54. The third circuit 54 comprises a first branch 54a connecting the first separator 26 to a softening device 56. The circulation of the heat transfer fluid 30 towards the softening device 56 is authorized for example by means of a first regulating valve 58 and a first pump 60.

[0059] The softening device 56 is configured to rid the heat transfer fluid 30 of potentially present acid gases. The softening device 56 comprises a discharge pipe 62 configured to discharge the acid residues of the heat transfer fluid 30 from the treatment device 1 in order to limit the risks of corrosion of all the components belonging to said cooling system 6.

[0060] The third circuit 54 also comprises a second branch 54b which connects the softening device 56 to the third heat exchanger 38 before returning to said softening device 56, thus forming a closed loop for circulation of the heat transfer fluid 30. The circulation of the heat transfer fluid 30 to the softening device 56 within the second branch 54b is controlled by a second regulating valve 58b and implemented by a second pump 61. It is understood here that the third heat exchanger 38 operates a heat exchange between the flow of gas loaded with carbon dioxide 2 and the heat transfer fluid 30.

[0061] Furthermore, a third branch 54c belonging to the third circuit 54 connects the second branch 54b to the second heat exchanger 36. It is thus understood that the second heat exchanger 36 operates a heat exchange between the flow of gas loaded with carbon dioxide 2 and the heat transfer fluid 30.

[0062] At the outlet of the second heat exchanger 36, the third branch 54c extends to the first heat exchanger 20 arranged within the heat exchange zone 16. The first heat exchanger 20 carries out a heat exchange between the flow of gas loaded with carbon dioxide 2 emitted by the emission source 10 and the heat transfer fluid 30 circulating within the third branch 54c, and this heat exchange leads to an evaporation of the heat transfer fluid 30, so as to create a superheated vapor which, ultimately, will increase the mass of the expanded gases at the energy recovery devices. The third branch 54c ends with a connection section 66 from the third circuit 54 to the second circuit 42. This connection section 66 is arranged downstream of an outlet 51 of the first heat exchanger 20, outside the heat exchange zone 16, and upstream of an inlet 53 of the first energy recovery device 50. The connection section 66 is terminated by an injection port in the second circuit 42.

[0063] The third circuit 54 also comprises a fourth branch 54d connecting the second separator 28 to the first separator 26. Within this fourth branch 54d, the circulation of the heat transfer fluid 30 is authorized by means of a third regulating valve 58c.

[0064] The third circuit 54 comprises a fifth branch 54e configured to channel the heat transfer fluid 30 from the third separator 46 to the softening device 56, in particular via a third pump 64.

[0065] The third circuit 54 further comprises a pipe 54f connected at the inlet to the third branch 54c and at the outlet to the branch 42b of the second circuit 42, such a pipe making it possible to mix the heat transfer fluid with the decarbonized gas flow 8. The heat transfer fluid is then evaporated and advantageously superheated. As a result, a larger gas volume is directed towards the energy recovery device 50. The mechanical expansion energy is thus increased. In other words, the residual heat available in the decarbonized gas flow recovered by the fourth heat exchanger 44 is used to produce heat transfer fluid vapor, preferably water vapor, which is mixed and expanded with the decarbonized gas flow.

[0066] The different branches 54a, 54b, 54c, 54d, 54e are configured to supply the heat transfer fluid 30 necessary for carrying out the heat exchange within the heat exchanger associated with the branch concerned.

[0067] [Fig. 3] shows the same treatment device 1 as that illustrated in [Fig. 2]. Unlike the latter, [Fig. 3] illustrates the circulation of the different flows within the cooling system 6 when the latter is in operation. The flow of gas loaded with carbon dioxide 2 is illustrated in a thick line. The flow of decarbonized gas 8 is illustrated in a thin line and the heat transfer fluid 30, both in liquid and gaseous state, is illustrated in a dotted line.

[0068] In [Fig.3], the flow of gas loaded with carbon dioxide 2 produced by the source emission 10, after having been previously expanded by the expansion device 14, reaches the chamber 18 of the heat exchange zone 16 via the first circuit 12. The first circuit 12 then directs the flow of gas loaded with carbon dioxide 2 leaving the heat exchange zone 16 to the first separator 26. The first separator 26 is at a confluence between the first circuit 12 and the third circuit 54, in this case the first branch 54a of the third circuit 54. The first separator 26 comprises a gas flow inlet loaded with carbon dioxide, a gas flow outlet loaded with carbon dioxide and a heat transfer fluid outlet. Said inlet and said gas flow outlet loaded with carbon dioxide are part of the first circuit 12, while the heat transfer fluid outlet delimits the third circuit 54.Thus, the first separator 26 is configured to recover the heat transfer fluid 30 present in the flow of gas loaded with carbon dioxide 2 with a view to sending it to the first branch 54a of the third circuit 54.

[0069] The flow of gas loaded with carbon dioxide 2 leaving the first separator 26 is then directed towards the first compression device 32 in order to raise its pressure, then towards the second heat exchanger 36 in order to lower its temperature. The second heat exchanger 36 comprises both a first pass which is part of the first circuit 12 and a second pass which is part of the third circuit 54. It is thus understood that the first pass is taken by the flow of gas loaded with carbon dioxide 2 and that the second pass is taken by the heat transfer fluid 30. Thus, the second heat exchanger 36 is configured to lower the temperature of the flow of gas loaded with carbon dioxide 2 circulating in the first pass by heat exchange with the heat transfer fluid 30 circulating in the second pass.It is understood here that the heat transfer fluid 30 recovers the heat present within the flow of gas loaded with carbon dioxide 2 via the second heat exchanger 36.

[0070] Subsequently, the first circuit 12 transports the flow of gas loaded with carbon dioxide 2 to the second separator 28. The second separator 28 is at a junction between the first circuit 12 and the third circuit 54, in this case the fourth branch 54d of the third circuit 54. The second separator 28 comprises an inlet for the flow of gas loaded with carbon dioxide, an outlet for the flow of gas loaded with carbon dioxide and a heat transfer fluid outlet. Said inlet and said outlet for the flow of gas loaded with carbon dioxide are part of the first circuit 12, while the heat transfer fluid outlet delimits the third circuit 54. Thus, the second separator 28 is configured to recover the heat transfer fluid 30 present in the flow of gas loaded with carbon dioxide 2 in order to conduct it to the softening device 56, via the fourth branch 54d.

[0071] The flow of gas loaded with carbon dioxide 2 leaving the second separator 28 is directed towards the second compression device 34 in order to raise its pressure, then towards the third heat exchanger 38 in order to lower its temperature. The third heat exchanger 38 comprises a first pass and a second pass. Thus, the third heat exchanger 38 is configured to lower the temperature of the flow of gas loaded with carbon dioxide 2 circulating in the first pass of the third heat exchanger 38 by heat exchange with the heat transfer fluid 30 circulating in the second pass of the third heat exchanger 38, in order to recover the calories present within the flow of gas loaded with carbon dioxide 2.

[0072] Leaving the third heat exchanger 38, the first circuit 12 transports the flow of gas loaded with carbon dioxide 2 to the third heat exchanger 40 in order to lower the temperature before conveying said cooled flow to the capture system 4 configured to generate the flow of decarbonized gas 8.

[0073] The flow of decarbonized gas 8 leaving the capture system 4 is recovered by the second circuit 42 which directs it to the third heat exchanger 40. Thus, it is understood that the third heat exchanger 40 is configured to lower the temperature of the flow of gas loaded with carbon dioxide 2 by heat exchange with the flow of decarbonized gas 8.

[0074] Leaving the third heat exchanger 40, the flow of decarbonized gas 8, having at this location a temperature for example equal to 37°C, is directed towards the fourth heat exchanger 44. At the outlet of the fourth heat exchanger 44, the flow of decarbonized gas 8 is mixed with the heat transfer fluid which comes from the pipe 54f, and the whole is directed towards the second heat exchanger 22 carrying out a heat exchange between the flow of gas loaded with carbon dioxide 2 present within the heat exchange zone 16 and the flow of decarbonized gas 8 mixed with the evaporated heat transfer fluid. This latter flow is then conveyed to the first energy recovery device 50. This flow of decarbonized gas 8 mixed with the evaporated heat transfer fluid then circulates through the second heat exchanger 24 and once again exchanges calories with the flow of gas loaded with carbon dioxide 2 present within the heat exchange zone 16.The decarbonized gases containing superheated water vapor are then reheated before a second expansion stage which takes place in the second energy recovery device 52.

[0075] This flow of decarbonized gas 8 mixed with the evaporated heat transfer fluid thus continues on its way to reach the second energy recovery device 52, where the expansion of this flow makes it possible to generate energy which can be exploited elsewhere. Downstream of the latter, the flow of decarbonized gas 8 circulates towards the fourth heat exchanger 44, then towards the third separator 46 to reach the management member 48.

[0076] The first heat exchanger 20 crossed by the circulating heat transfer fluid 30 in the third branch 54c belonging to the third circuit 54 is configured to vaporize the heat transfer fluid 30, by heat exchange with the flow of gas loaded with carbon dioxide 2 coming from the emission source 10. The vaporized heat transfer fluid 30 circulating within this first heat exchanger 20 is connected to the second circuit 42 by the connection section 66, the latter being a port for injecting the heat transfer fluid 30 into the flow of decarbonized gas 8.

[0077] It is understood here that the vaporized heat transfer fluid 30 circulating in the third circuit 54c is mixed with the flow of decarbonized gas 8 circulating in the second circuit 42 in order to increase the heat exchanges, which has the effect of improving the overall performance of the treatment device 1.

[0078] The invention also relates to a cooling method implementing the cooling system 6 for the flow of gas loaded with carbon dioxide 2, where the heat transfer fluid 30 is evaporated and superheated by heat exchange with the flow of gas loaded with carbon dioxide 2 via the heat exchanger 20 arranged within the thermal zone 16, then the evaporated heat transfer fluid 30 is injected into the flow of decarbonized gas 8 circulating in the second circuit 42, in particular upstream of the energy recovery device 50, 52.

[0079] The invention, as just described, achieves the aim it set itself, namely to propose an optimized solution for recovering and exploiting the calories present in a flow of gas loaded with carbon dioxide emitted by an emission source, in order to improve the energy performance of a treatment device that said cooling system equips. Applied to carbon dioxide, such a solution makes it possible to reduce the greenhouse effect.

[0080] The present invention cannot, however, be limited to the means and configurations described and illustrated here and it also extends to any equivalent means and configuration as well as to any technically effective combination of such means.

Claims

Claims

1. Cooling system (6) for a flow of gas loaded with carbon dioxide (2) comprising a first circuit (12) configured to be traversed by the flow of gas loaded with carbon dioxide (2) and a second circuit (42) configured to be traversed by a flow of decarbonized gas (8), said system comprising at least one heat exchange zone (16) between the first circuit (12) and the second circuit (42), said zone (16) comprising at least one heat exchanger (22, 24) configured to carry out a heat exchange between the flow of gas loaded with carbon dioxide (2) and the flow of decarbonized gas (8), the cooling system (6) comprising a third circuit (54) configured to be traversed by a heat transfer fluid (30) and which comprises at least one heat exchanger (20) configured to vaporize said heat transfer fluid (30) by heat exchange with the flow of gas loaded with carbon dioxide (2),said heat exchanger (20) being arranged in the heat exchange zone (16), the third circuit (54) being connected to the second circuit (42).,

2. Cooling system (6) according to claim 1, comprising at least one compression device (, 32, 34) of the flow of gas loaded with carbon dioxide (2) arranged on the first circuit (12).

3. Cooling system (6) according to any one of claims 1 or 2, wherein the heat exchanger configured to vaporize the heat transfer fluid (30) by heat exchange with the gas loaded with carbon dioxide (2) is a first heat exchanger (20), the third circuit (54) comprising a second heat exchanger (36) configured to carry out a heat exchange between the flow of gas loaded with carbon dioxide (2) and the heat transfer fluid (30), said second heat exchanger (36) being arranged on the first circuit (12), downstream of the compression device (, 32, 34).

4. Cooling system (6) according to any one of claims 1 to 3, characterized in that the heat transfer fluid (30) comprises mainly water.

5. Cooling system (6) according to any one of claims 1 to 4, comprising at least one separator (26, 28) configured to collect the heat transfer fluid (30) present within the flow of gas loaded with carbon dioxide (2).

6. Cooling system (6) according to any one of the claims- indications 1 to 5, in which the third circuit (54) comprises a softening device (56) for the heat transfer fluid (30).

7. Cooling system (6) according to claim 6, comprising a plurality of separators (26, 28) configured to collect the heat transfer fluid (30) present within the flow of gas loaded with carbon dioxide (2), said separators (26, 28) being connected to the softening device (56).

8. Cooling system (6) according to any one of claims 1 to 7, in which the second circuit (42) comprises at least one energy recovery device (50) generated by the flow of decarbonized gas (2), the connection of the third circuit (54) to the second circuit (42) being made between an outlet (51) of the heat exchanger (22) and an inlet (53) of the energy recovery device (50).

9. Cooling system (6) according to any one of claims 1 to 8, in which the heat exchange zone (16) comprises a chamber (18) intended to be traversed by the flow of gas loaded with carbon dioxide (2), the heat exchanger (22) and the heat exchanger (20) extending within the chamber (18).

10. Device (1) for treating a gas loaded with carbon dioxide comprising a cooling system (6) according to any one of claims 1 to 9 and a system (4) for capturing carbon dioxide present in the flow of gas loaded with carbon dioxide (2), the capture system (4) being configured to extract at least part of the carbon dioxide and return the flow of decarbonized gas (8) to the cooling system (6).

11. Method for cooling a flow of gas loaded with carbon dioxide (2) using a cooling system (6) according to any one of claims 1 to 9, during which: - the heat transfer fluid (30) is evaporated by heat exchange with the flow of gas loaded with carbon dioxide (2); - the evaporated heat transfer fluid (30) is injected into the flow of decarbonized gas (8).

12. Cooling method according to claim 11, during which the flow of decarbonized gas (8) is saturated with heat transfer fluid (30) before it enters the heat exchanger (22).

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