A device for treating exhaust gases emitted by fuel-consuming devices

Abstract

A device (300) for treating at least a portion of an exhaust gas discharged by at least one fuel consuming device (100), comprising at least one compression member (320) designed to increase the pressure of at least a portion of the exhaust gas (FE1) discharged by the fuel consuming device (101) and at least one unit (310) for capturing carbon dioxide present in the exhaust gas (FE), the compression member (320) and the unit (310) for capturing carbon dioxide are arranged between the fuel consuming device (101) and a turbocharger (120), the turbine (122) of the turbocharger is designed to be powered by the exhaust gases (FE2, FE3) and the compressor (121) of the turbocharger is designed to supply an oxidant to the fuel consuming device (101).

Description

[Technical field]

[0001] The present invention relates to the field of engines powered by natural gas, in particular engines for propelling or driving accessories installed on ships capable of containing and / or transporting liquefied natural gas, or engines installed in gas terminals.

[0002] Such ships therefore conventionally comprise tanks containing natural gas in liquid state. Natural gas is liquid at atmospheric pressure at temperatures below -160°C. These tanks are not completely insulated so that the natural gas at least partially evaporates therein. These tanks therefore contain both natural gas in liquid form and in gaseous form. This natural gas in gaseous form forms the upper part of the tank and the pressure of this upper part of the tank must be controlled so as not to damage the tank. Thus, in the known method, at least a portion of the natural gas present in the tank in gaseous form is used, inter alia, to power the propulsion engines of the ship.

[0003] These engines consume natural gas and emit exhaust gases that may be routed to a turbocharger turbine to drive a turbocharger shaft that is itself rotatably connected to a turbocharger compressor that is then designed to compress air and supply the compressed air to the engine.

[0004] The exhaust gases emitted by these engines are then released into the atmosphere. These exhaust gases, resulting from the combustion of the natural gas supplied to the engines, contain high concentrations of carbon dioxide, which is then released into the atmosphere along with the rest of the exhaust gases. Summary of the Invention

[0005] It is now known that carbon dioxide is one of the main air pollutants and new standards are gradually being introduced that force ship owners to significantly reduce these carbon dioxide emissions. The present invention falls within this context by providing a device for treating exhaust gases that is suitable to be installed on ships as defined above and that makes it possible to reduce the level of carbon dioxide in these exhaust gases.

[0006] An object of the present invention therefore relates to a device for treating at least a portion of the exhaust gas discharged by at least one fuel consuming device, for example a ship, the treatment device comprising at least one compression member designed to increase the pressure of at least a portion of the exhaust gas discharged by the fuel consuming device and at least one unit for capturing carbon dioxide present in the exhaust gas, the compression member and the unit for capturing carbon dioxide being arranged between the fuel consuming device and a turbocharger, the turbine of which is designed to be powered by the exhaust gas and the compressor of which is designed to supply an oxidant to the fuel consuming device.

[0007] In other words, it is understood that the device for treating exhaust gases according to the invention makes it possible to treat at least a portion of the gases discharged by the fuel consuming device before they are reused to rotate the turbocharger and thus supply the fuel consuming device with oxidant. Advantageously, such a device therefore makes it possible to capture carbon dioxide from the exhaust gases when said gases have the highest concentration of carbon dioxide. As a result, the equipment used, in particular the unit for capturing carbon dioxide, has the smallest possible dimensions and therefore a limited volume.

[0008] The fuel may be liquefied petroleum gas, heavy fuel oil, extra low sulfur fuel oil, diesel, methanol, leaded or unleaded gasoline, or a cryogenic fluid such as liquefied natural gas or liquefied petroleum gas stored in a tank, e.g., a vessel equipped with a device for treating smoke and a fuel consumption apparatus as described herein.

[0009] According to a feature of the invention, the device for treating exhaust gases comprises at least one cooling means designed to cool the exhaust gases emitted by the fuel-consuming device upstream of a unit for capturing carbon dioxide, and at least one heating means designed to heat the exhaust gases downstream of the capture unit. The terms "upstream" and "downstream" are understood here with respect to the direction of movement of the exhaust gases. In other words, the cooling means are designed to cool the gas charged with carbon dioxide and the heating means are designed to heat the gas depleted of carbon dioxide. Advantageously, the cooling means and the heating means can work together, i.e. the heat present in the exhaust gas charged with carbon dioxide is used to heat this exhaust gas depleted of carbon dioxide, which makes it possible to simultaneously cool the gas charged with carbon dioxide.

[0010] Advantageously, the device for treating exhaust gases according to the invention is designed to reduce the concentration of CO2 in the exhaust gases to a level of up to 80%, advantageously 40%. In other words, the treatment device according to the invention is designed so that the exhaust gases discharged into the atmosphere have a carbon dioxide concentration that is 40% lower than the carbon dioxide concentration in the exhaust gases leaving the fuel consuming device.

[0011] According to a first embodiment of the invention, the unit for capturing carbon dioxide comprises an absorption device adapted for at least a portion of the exhaust gas passing through the compression member, said absorption device being arranged on a solvent circuit in which a solvent designed to capture the carbon dioxide present in said exhaust gas circulates. According to a feature of this first embodiment, the solvent circuit may comprise at least the absorption device, a member for circulating the solvent, at least one member for regenerating the solvent designed to enable the solvent to be stripped of the captured carbon dioxide, at least a first heat exchanger designed to exchange heat between the solvent loaded with carbon dioxide and the solvent stripped of this carbon dioxide, and at least a second heat exchanger designed to cool the solvent upstream of the absorption device relative to the direction of circulation of the solvent in the solvent circuit.

[0012] For example, the solvent may include an amine, an amine salt, a sodium hydroxide solution, a bicarbonate solution, or an alkaline solution. By way of example, the solvent may include one or a mixture of the following components: monoethanolamine (MEA), aminoethylethanolamine (AEEA), sodium hydroxide (NaOH), bisulfite (H2SO3), diethanolamine (DEA), diethylenetriamine (DETA), aminomethylpropanol (TEA), methyldiethanolamine (MDEA), and piperazine (PZ). Advantageously, the regenerating member is designed so that the carbon dioxide removed therein can be recovered in liquid form. The carbon dioxide is then stored in a liquid state and at high pressure.

[0013] According to a second embodiment, the unit for capturing carbon dioxide comprises at least one refrigerant circuit in which at least a first heat exchanger suitable for exchanging heat between a refrigerant in liquid state and gas, for example extracted from a tank of the ship, and at least a second heat exchanger suitable for exchanging heat between the refrigerant cooled by passage of the refrigerant through the first heat exchanger and at least a portion of the exhaust gas are arranged.

[0014] The result of the heat exchange taking place in the second heat exchanger is the freezing of the carbon dioxide in the second heat exchanger. To recover the carbon dioxide, the heat exchanger is closed so that its temperature is raised to at least the liquefaction temperature of the carbon dioxide. The carbon dioxide can then be stored in the liquid state and at high pressure, similar to what has been described above with reference to the first embodiment.

[0015] The present invention also relates to a system for supplying gas to at least one fuel consuming device, for example a gas carrier, the supply system comprising at least one tank containing gas in a liquid and gaseous state, at least one line for supplying gas to the fuel consuming device, at least one turbocharger designed to supply an oxidizer to the fuel consuming device and at least one device for processing the above-mentioned gas, the gas supply line comprising at least one heat exchanger designed to evaporate the gas taken from the tank in a liquid state and at least one compression device suitable for increasing the pressure of the gas to a pressure suitable for the needs of the fuel consuming device.

[0016] The present invention also relates to a method for treating exhaust gases emitted by a fuel consuming device using at least one device for treating exhaust gases as described above, comprising at least separating exhaust gas emitted by a fuel consuming device into a first portion of exhaust gas and a second portion of exhaust gas; providing a first portion of the exhaust gas to a compression member; compressing a first portion of the exhaust gas with a compression member; supplying a first portion of the compressed exhaust gas to a unit for capturing carbon dioxide; - capturing carbon dioxide present in a first portion of the exhaust gas by a unit for capturing carbon dioxide; mixing a first portion of the exhaust gas exiting the unit for capturing carbon dioxide with a second portion of the exhaust gas to form a mixed gas; supplying the mixed gas to a turbocharger; cooling the gas mixture exiting the turbocharger; and discharging the cooled mixed gas to atmosphere.

[0017] According to a feature of the method for treating a gas according to the invention, the second portion of the exhaust gas and the first portion of the exhaust gas are different from each other.

[0018] For example, the first portion of exhaust gases represents 10% to 90% of all of these exhaust gases, such as 50% of these exhaust gases, and the second portion of exhaust gases represents 90% to 10% of all of these exhaust gases, such as 50% of these exhaust gases.

[0019] The first portion of the exhaust gas and the second portion of the exhaust gas may be added together to form an exhaust gas emitted by the fuel consuming device.

[0020] The invention further relates to a ship for transporting liquefied gas, comprising at least one fuel consuming device as described above and at least one device for treating at least a portion of the exhaust gas emitted by the fuel consuming device.

[0021] Finally, the invention relates to a system for loading or unloading liquid gas, which combines at least one onshore facility as described above and at least one vessel for transporting the liquid gas.

[0022] The invention also relates to a method for loading or unloading liquid gas from a ship as described above.

[0023] Other characteristics, details and advantages of the invention will become more apparent from reading the specification that follows and from embodiments given by way of example, without limitation, with reference to the attached drawings, in which: [Brief description of the drawings]

[0024] [Figure 1] 1 shows diagrammatically a system for supplying gas to at least one fuel consuming device according to the invention, comprising at least one device for treating exhaust gases according to the invention; [Diagram 2] 2 illustrates a schematic diagram of the gas supply system shown in FIG. 1 according to an alternative embodiment of the present invention; [Diagram 3] 2 shows a schematic diagram of a first embodiment of the device for treating exhaust gases as shown in FIG. 1; [Figure 4] 2 shows a schematic representation of a second embodiment of the device for treating exhaust gases shown in FIG. 1; [Diagram 5] FIG. 1 is a cutaway schematic diagram of a tank of an LNG carrier and a terminal for loading and / or unloading the tank. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0025] In the remainder of this specification, the terms "upstream" and "downstream" are to be understood according to the direction of circulation of a liquid, gas or two-phase fluid through the element in question.

[0026] FIG. 1 shows a schematic representation of a system 100 for supplying gas to at least one fuel consuming device 101, the system comprising a device 300 for treating exhaust gas emitted by the at least one fuel consuming device 101, and FIG. 3 and FIG. 4 show a schematic representation of a device 300 for treating exhaust gas according to a first embodiment of the invention and a second embodiment of the invention, respectively. As shown, the supply system 100 comprises at least one tank 200 for containing a fuel, for example a gas, intended to be supplied to the at least one fuel consuming device 101, the gas being contained in said tank 200 in liquid and gaseous states. The following description shows a particular example of application of the invention, in which the tank 200 contains liquefied natural gas, liquefied petroleum gas, heavy fuel oil, extra-low sulfur fuel oil, diesel, methanol or leaded or unleaded gasoline. It is understood that this is only one example of application, and that the fuel supply system 100 according to the invention can be used with different types of liquid or gaseous fuels, for example hydrocarbon or hydrogen gas. Similarly, although the figures show a system for supplying fuel to one fuel consuming device, it will be understood that the system may be suitable for supplying two or more gas consuming devices without departing from the context of the invention.

[0027] Thus, a fuel supply system as described in this document may be a gas supply system.Throughout this document, a fuel consuming device may be considered to be a gas consuming device.

[0028] In the remainder of this specification, unless otherwise stated, the term "fuel consuming device" refers to one or more gas consuming devices or devices. Furthermore, the terms "system 100" and "fuel system 100" are used interchangeably, as are the terms "exhaust gas discharged by the fuel consuming device", "exhaust gas" and "gas", and the terms "fuel consuming device 101" and "device 101". In the figures, dashed lines indicate the circuit portions through which gas or refrigerant drawn from the tank circulates, and solid lines indicate the circuit portions through which exhaust gas discharged by the fuel consuming device circulates.

[0029] Thus, Fig. 1 shows a supply system 100 according to the invention, comprising at least a tank 200 for containing gas in liquid and gaseous state, at least one gas supply line 110 of a fuel consuming device 101, at least one turbocharger 120, at least one unit 310 for capturing carbon dioxide (hereinafter carbon dioxide is designated by the symbol "CO2"), at least one cooling means 301, at least one heating means 302 and at least one compression member 320. According to the illustrated examples, the compression member 320 is arranged upstream of the unit 310 for capturing CO2. In other words, according to these examples, the exhaust gases undergo an increase in their pressure before reaching this capture unit 310. Alternatively, the compression member 320 can be positioned downstream of this unit for capturing CO2. In any case, this compression member 320 makes it possible to compensate for the pressure drop associated with the capture of CO2 by the processing device 300.

[0030] The cooling means 301 make it possible to reduce the temperature of the exhaust gases before they reach the capture unit 310. According to the example shown, the cooling means 301 are arranged between the compression member 320 and the capture unit 310, but it is understood that this is only an exemplary embodiment of the invention and that the positions of these components can for example be reversed without departing from the context of the invention. The heating means 302 are arranged, according to the example shown in Fig. 1, downstream of the capture unit 310, the function of which will be explained more fully below. Fig. 2 shows an alternative embodiment of the system 100 which differs from the one described below, in particular due to the arrangement of the cooling means 301, the compression member 320 and the heating means 302 relative to the unit 310 for capturing CO2.

[0031] The supply line 110 comprises at least one heat exchanger 111 designed to evaporate the gas taken from the tank 200 in a liquid state, and at least one compression device 112 designed to increase the pressure of the gas leaving the heat exchanger 111 to a pressure adapted to the needs of the fuel consuming device 101. In other words, the gas leaving the supply line 110 is in a gaseous state and has a pressure adapted to the needs of the fuel consuming device 101.

[0032] The illustrated example shows a situation in which gas is extracted from a tank 200 in liquid state. For this purpose, at least one pump 113 is placed at the bottom of the tank 200, i.e. the pump 113 is immersed in the gas present in liquid state in said tank 200. The heat exchanger 111 comprises at least a first path 114 and at least a second path 115, which is designed to exchange heat between a fluid circulating in said first path 114 and a fluid circulating in said second path 115.

[0033] As shown, the gas taken from the tank 200 in liquid state is fed to a first path 114 of a heat exchanger 111. The fluid circulating in the second path 115 of this heat exchanger 111 is then selected such that the heat exchange between this fluid and the gas in liquid state leads to the evaporation of this gas in liquid state. For example, the fluid circulating in the second path 115 can be seawater taken from the vicinity of the vessel equipped with the system 100 according to the invention. Thereby, the gas circulating in the first path 114 captures heat from the seawater circulating in the second path 115 such that this gas evaporates and leaves the first path 114 in gaseous state. The gas in gaseous state then reaches a compression device 112 where it undergoes compression, i.e. an increase in pressure, to reach a pressure compatible with the needs of the fuel consuming device 101.

[0034] According to an example not shown here, the gas can be taken from the tank in gaseous state, in which case the heat exchanger is designed to increase the temperature of this gas without changing the state of said gas. The heated gas then reaches the compression device as described above with reference to the example shown.

[0035] According to the illustrated example, a fuel consuming device 101 requires an air supply. This fuel consuming device 101 can be, for example, a propulsion engine of a ship equipped with a system 100 according to the invention. In order to make it possible to supply the fuel consuming device 101 with an oxidizer, the system 100 comprises a turbocharger 120. This turbocharger 120 comprises at least one compressor 121 designed to draw in and compress, i.e. increase the pressure of, an air flow FA before sending it to be supplied to the device 101, and to power at least one turbine 122, part of which is designed to rotate a shaft 123 rotatably connected to the compressor 121. Advantageously, the turbine 122 is powered by the exhaust gases discharged by the fuel consuming device 101. In other words, the fuel consumer 101 consumes gas drawn from the tank 200 and emits exhaust gases at the outlet which are then used to power the turbine 122, which in turn drives a shaft 123 which rotates a compressor 121 capable of compressing air which is then supplied to the fuel consumer 101. The exhaust gases leaving the turbocharger 120 are then discharged into the atmosphere.

[0036] According to the illustrated embodiment, the exhaust gases emitted by the fuel consuming device 101 have a pressure of about 3 bar. For example, these gases may escape the device 101 at a pressure of 3.5 bar. It will be understood that this is by way of example only and that these exhaust gases may have a pressure greater than or less than 3 bar without departing from the context of the invention.

[0037] In order to limit the impact of the system 100 on the environment, it further comprises a device 300 for treating the exhaust gases. As mentioned above, this treatment device 300 comprises cooling means 301, heating means 302, a compression member 320 and a unit 310 for capturing CO2. The components of the capture unit 310 are explained in more detail below and vary depending on the embodiment implemented.

[0038] A method for processing gases is now described that implements the system 100 according to the invention, and more particularly the device for processing gases 300 according to the invention.

[0039] The operation of the supply line 110 has been described above and will not be repeated in detail here. The exhaust gases FE discharged by the fuel consuming device 101 take a first duct 102 extending between the fuel consuming device 101 and a connection point 103 from which extend at least a second duct 104 and a third duct 105, the third duct 105 carrying at least one flow control member 106. Here, the term "flow control member" means any member capable of controlling the flow of gases in the duct carrying said flow.

[0040] The second duct 104 extends between the connection point 103 and the turbocharger 120, more specifically between the connection point 103 and an inlet 124 of a turbine 122 of said turbocharger 120. The third duct 105 extends between the connection point 103 and the treatment device 300. According to the illustrated example, this third duct 105 extends more specifically between the connection point 103 and a compression member 320. This compression member 320 is connected to a unit for capturing CO2 310 by a fourth duct 107 that extends from this compression member 320 to the capture unit 310, this fourth duct 107 carrying the cooling means 301. The heating means 302 are arranged on a fifth duct 108 that extends between the capture unit 310 and the connection point 103.

[0041] A sixth duct 109 finally extends between an outlet 125 of the turbine 122 and the environment outside the system 100, this sixth duct 109 carrying at least one member 126 for cooling the exhaust gases. This cooling member 126 is therefore designed to cool the exhaust gases before they are discharged into the atmosphere.

[0042] The exhaust gases FE discharged by the fuel consumption device 101 reaching the connection point 103 are divided into two by the flow control member 106. This flow control member 106 thus allows a first portion FE1 of the exhaust gases FE to take the third duct 105, while at the same time a second portion FE2 of the exhaust gases FE takes the second duct 104. According to the invention, the second portion FE2 of the gases FE is different from these first portions FE1 of the exhaust gases FE. For example, it is possible that the second portion FE2 represents 90% to 10%, in particular 50%, of all the exhaust gases FE, and the first portion FE1 represents 10% to 90%, for example 50%, of all the exhaust gases FE, and the first portion FE1 and the second portion FE2 together represent 100% of the exhaust gases.

[0043] Thus, half of the gas FE exhausted by the fuel consuming device 101 is directed directly to the inlet 124 of the turbine 122, while the other half is directed to the device for treating gases 300. In other words, only half of the exhaust gases are treated by the device for treating gases 300. Advantageously, this makes it possible to reduce the size of the elements that make up the device for treating gases 300, and thus the overall dimensions of this device for treating gases 300.

[0044] The first portion FE1 of the exhaust gases takes the third duct 105 and reaches the compression element 320 and the cooling means 301, where these gases undergo an increase in their pressure and a decrease in their temperature. As mentioned above, the gases FE escape from the fuel consuming device 101 at a pressure of about 3.5 bar. According to the illustrated example, the compression element 320 is then designed to increase the pressure of the first portion FE1 of the gases to a pressure of about 4.5 bar. The first portion FE1 of the gases at high pressure and low temperature then reaches the unit for capturing CO2 310, where at least a part of the CO2 that these gases contain is removed from said gases. For example, this unit 310 for capturing CO2 is designed to retain 80% of the CO2 present in this first portion FE1 of the gases. These gases, from which most of the CO2 has been removed, then take the fifth duct 108, which extends between the capture unit 310 and the connection point 103. Along this fifth duct 108, the first part of gas FE1 passes through heating means 302 and its temperature increases. The first part of gas FE1 then reaches the connection point 103, where this first part of gas FE1 freed of CO2 reaches and mixes with the second part of gas FE2 discharged by the fuel consumer 101. The mixture thus produced of the second part of gas FE2 and the first part of gas FE1 freed of CO2 is then used to power the turbine 112 of the turbocharger 121, i.e. this mixture takes the second duct 104 to the inlet 124 of the turbine 112. In the remainder of this description, the gas circulating in this second duct 104 is therefore called "mixed gas FE3".

[0045] From the above, it can be seen that the mixed gas FE3 circulating in the second duct 104 has a lower CO2 level than the CO2 level present in the exhaust gas FE discharged by the fuel consuming device, i.e. the exhaust gas FE circulating in the first duct 102. According to the illustrated example, the mixed gas FE3 has a CO2 level that is 40% lower than the CO2 level present in the gas FE discharged by the device 101 and circulating in the first duct 102.

[0046] These carbon dioxide depleted gas mixtures FE3 may then be directed to the cooling member 126 to be cooled and then discharged to the atmosphere.

[0047] Figure 2 shows an alternative embodiment of the system 100 shown in Figure 1, in which the operation of the cooling means 301 and the heating means 302 are interdependent. To facilitate understanding of the drawing, only the device for processing gas 300 is shown in detail in this figure (Figure 2).

[0048] As shown, the treatment device 300 according to this alternative embodiment comprises at least a first heat exchange means 303, at least a second heat exchange means 304, at least a unit for capturing CO2 310, and at least a compression member 320.

[0049] Thus, the first portion FE1 of the gas first reaches the first heat exchange means 303 and then the second heat exchange means 304 before reaching the unit for capturing CO2 310. The first portion FE1 of the gas from which CO2 has been removed then reaches the compression member 320 before passing again through the first heat exchange means 303 and then reaching the second duct 104 as described above.

[0050] In particular, the first heat exchange means 303 here takes the form of a heat exchanger comprising at least a first path 307 through which the CO2-charged gas circulates and at least a second path 308 through which the CO2-depleted gas circulates. The first heat exchange means 303 thus allows to exchange heat between the CO2-charged gas and the CO2-depleted gas, resulting in an increase in the temperature of the CO2-depleted gas and a decrease in the temperature of the CO2-charged gas. The heated gas can thus be remixed in the second duct 104 with the gas discharged by the fuel consumer 101 and not treated by the device for treating gases 300. The CO2-charged gas, part of which is partially cooled, reaches the second heat exchange means 304, which is designed to exchange heat between these partially cooled gases and seawater in order to further cool the gas and thus enable its treatment by the capture unit 310. For example, the gas may arrive at the unit for capturing CO2 310 at a temperature of about 35°C, while the gas arrives at the inlet of the first heat exchange means 303 at a temperature of about 350°C.

[0051] As mentioned above, the passage through the unit 310 for capturing CO2 causes a pressure drop that needs to be compensated for before the CO2-depleted gas is returned to the second duct 104. Therefore, according to this alternative, the compression member 320 is arranged downstream of the unit 310 for capturing CO2 with respect to the circulation direction of the gas in the treatment device 300.

[0052] It is therefore understood that the cooling means 301 are provided by the first heat exchange means 303 and the second heat exchange means 304, and the heating means 302 are provided by the first heat exchange means 303, according to the alternative shown in Fig. 2. The compression member 320 is also responsible for increasing the temperature of the CO2-exhausted gas by increasing its pressure. Such an arrangement therefore makes it possible to directly use the heat carried by the gas, without the need to supply external energy to the device 300 for treating the gas.

[0053] Optionally, the flow separator 305 can be arranged upstream of the first heat exchange means 303 with respect to the circulation direction of the CO2-filled gas, and the flow mixer 306 can be arranged downstream of this first heat exchange means 303 with respect to the circulation direction of the CO2-depleted gas.

[0054] Two embodiments of a device 300 for processing a gas will now be described with reference to Figures 3 and 4, where Figure 3 shows a processing device 100 according to a first embodiment and Figure 4 shows a processing device 100 according to a second embodiment.

[0055] According to a first embodiment, the CO2 is captured using a solvent, whereas according to a second embodiment, the capture unit makes it possible to carry out what is known as "cryogenic" capture. In other words, the first embodiment differs from the second embodiment because of the elements that make up the capture unit 310. According to other embodiments (not shown), the CO2 is captured by a membrane process, by non-chemical absorption, i.e. without a solvent, or by adsorption.

[0056] Thus, according to a first embodiment shown in Figure 3, a unit 310 for capturing CO2 comprises a solvent circuit 330, i.e. a circuit 330 in which a solvent circulates, a compression member 320, cooling means 301 and heating means 302. Figure 3 shows an embodiment in which the cooling means 301, the heating means 302 and the compression member 320 are provided according to the example shown in Figure 1, but it is understood that they may be arranged as described and illustrated in the alternative form shown in Figure 2 without departing from the context of the invention.

[0057] The solvent circuit 330 comprises at least one absorption device 331 designed to extract CO2 from the exhaust gas, at least one regeneration element 332 designed to extract CO2 from the solvent, at least one element 333 for circulating the solvent, and at least one element 334 for circulating the solvent S charged with carbon dioxide. +CO2 The solvent S from which the carbon dioxide has been removed -CO2and at least a second heat exchanger 335 designed to cool the solvent upstream of the absorption device 331, i.e. the solvent from which the CO2 has been removed.

[0058] Thus, the first portion FE1 of the exhaust gases first reaches the absorption device 331 where it comes into contact with a solvent circulating in the solvent circuit 330. The solvent is selected for its ability to react with the carbon dioxide present in the gases in order to extract this CO2 from these gases. The first portion FE1 of the exhaust gases therefore leaves the absorption device 331 with some of its CO2 removed. According to the invention, the device 300 for treating a gas is more particularly designed so that the first portion FE1 of the gas leaves the absorption device with about 80% of the CO2 it carries removed. For example, the solvent may comprise an amine, an amine salt, a sodium hydroxide solution, a bicarbonate solution or an alkaline solution. By way of example, the solvent may include one or a mixture of the following components: monoethanolamine (MEA), aminoethylethanolamine (AEEA), sodium hydroxide (NaOH), bisulfite (H2SO3), diethanolamine (DEA), diethylenetriamine (DETA), aminomethylpropanol (TEA), methyldiethanolamine (MDEA), and piperazine (PZ).

[0059] Solvent S filled with CO2 +CO2 The solvent S then leaves the absorption device 331 and reaches the first heat exchanger 334. +CO2 The CO2 reaches the regeneration element 332, which removes the CO2 captured in the absorption device 331. The solvent S with the carbon dioxide removed is -CO2 The CO2-loaded solvent S exits the regeneration element 332 and reaches the first heat exchanger 334 again, where the first heat exchanger converts the CO2-loaded solvent S +CO2 As a result of this heat exchange, the CO2-filled solvent S +CO2 is heated and at the same time, the solvent S from which CO2 has been removed -CO2The regenerator 332 is adapted, in part, to capture the CO2 in a liquid state to enable storage. More specifically, the CO2 is captured in liquid form and then compressed and stored at high pressure.

[0060] The cooled, CO2-free solvent S -CO2 The CO2-depleted solvent S, which has been cooled by passing through the first heat exchanger 334, reaches the second heat exchanger 335 where it is cooled again. For example, this second heat exchanger 335 may -CO2 The device 300 for processing gases may be designed to exchange heat between the solvent circuit 330 and seawater. It is understood that this is only one embodiment and that the seawater may be replaced by any known refrigerant compatible with the present invention without departing from the context of the present invention. In any case, the solvent circuit 330, and more generally the device 300 for processing gases, may be designed to exchange heat between the solvent S, which has been stripped of gas and CO2, and the seawater. -CO2 The solvent S, which is stripped of gas and CO2, is designed to reach the absorption device 331 at a similar temperature. -CO2 may have a temperature of about 35° C. at the inlet of the absorption device 331.

[0061] The CO2 is then removed and the cooled solvent S -CO2 can again reach the absorption device 331 and restart the cycle on the solvent circuit 330.

[0062] Finally, Figure 4 shows a device 300 for treating gases according to a second embodiment of the invention. As mentioned before, the capture of CO2 according to the second embodiment is carried out by freezing it. In other words, this second embodiment consists in cooling at least a portion of the exhaust gases to a temperature at which the CO2 becomes solid. At the pressures involved, this temperature is approximately -125°C.

[0063] For this purpose, the unit 310 for capturing CO2 comprises at least a first heat exchanger 311 designed to exchange heat between the gas taken from the tank 200 in the liquid state and the refrigerant FR, and at least a second heat exchanger 312 designed to exchange heat between a first portion FE1 of the exhaust gas and the refrigerant FR. As shown, the first heat exchanger 311 and the second heat exchanger 312 are arranged on a refrigerant circuit FR, which further comprises at least one compression means 313 designed to increase the pressure of the refrigerant FR and at least one expansion means 314 designed to reduce the pressure of this refrigerant FR. The first heat exchanger 311 thus comprises at least a first path 315 participating in the formation of the supply line 110 of the fuel consuming device 101 and at least a second path 316 through which the refrigerant FR passes.

[0064] From the above, it can be seen that the first heat exchanger 311 has a similar function to the heat exchanger of the supply line described above with reference to Figure 1, namely to evaporate the gas extracted from the tank 200 in liquid state, in order to supply it to the fuel consumption device 101. The first heat exchanger 311 therefore differs from the aforementioned heat exchangers in that it is designed to exchange heat not between the gas extracted from the tank 200 and seawater, but between the refrigerant FR and the gas extracted from the tank 200.

[0065] The processing device 300 according to this second embodiment also comprises cooling means 301 and heating means 302. The example shown in Figure 4 repeats the arrangement described with reference to Figure 1, but it is understood that the cooling means 301 and heating means 302 can be arranged according to the example shown and described with reference to Figure 2 without departing from the context of the invention.

[0066] The term "refrigerant" is understood here to mean any fluid designed to capture, exchange and transport heat by changing state. The refrigerant FR thus reaches the compression means 313 in gaseous state and at low pressure and leaves it there in gaseous state and at high pressure. It then reaches this first heat exchanger 311, more specifically the second pass 316 of this first heat exchanger 311, where it gives up heat to the gas circulating in particular in the first pass 315, which causes it to condense. It then reaches the expansion means 314, where the pressure of the refrigerant FR is reduced. It thus reaches the second heat exchanger 312, more specifically the first pass 317 of this second heat exchanger 312, in a liquid or two-phase state and at low pressure. In this second heat exchanger 312, the refrigerant captures heat and thus evaporates, leaving this second heat exchanger 312 in gaseous state and at low pressure to reach the compression means 313 again, starting a new cycle. Advantageously, the refrigerant FR can return through the first heat exchanger 311, more particularly through the third pass 318 of this first heat exchanger 311, before reaching the compression means 313, as shown in Figure 4. The second pass 315 and the third pass 318 of this first heat exchanger 311 thus form an internal heat exchanger making it possible to pre-cool the refrigerant upstream of the expansion means 315, i.e. the refrigerant circulating in the second pass 316, and to pre-heat the refrigerant upstream of the compression means 313, i.e. the refrigerant circulating in the third pass 318 of this first heat exchanger 311.

[0067] The terms "low pressure" and "high pressure" are understood here relative to one another, i.e. the term "low pressure" means "pressure lower than high pressure". The terms "upstream" and "downstream" are understood with respect to the direction of circulation of the refrigerant FR in the refrigerant circuit.

[0068] The first portion FE1 of the exhaust gases first reaches, in part, the second heat exchanger 312, more specifically the second pass 319 of this second heat exchanger 312, where it transfers heat to the refrigerant FR, evaporating this refrigerant and cooling the gas FE1. The device 300 for treating exhaust gases is designed such that the cooling carried out in this second heat exchanger 312 is sufficient to cause the solidification of the CO2 present in the first portion FE1 of the gases. In particular, the CO2 freezes in the second heat exchanger 312, such that the gas leaving this second heat exchanger has a CO2 level 40% lower than the proportion that this same gas had upstream of the second heat exchanger 312. The CO2-free gas then reaches the first heat exchanger 311, more specifically the fourth pass 410 of this first heat exchanger 311, in which it captures the heat rejected by the refrigerant FR so as to heat it and condense the latter. The CO2-free gas can then be heated by the heating means 302 and then remixed with a second portion of the exhaust gas, part of which is sent directly to the turbocharger as described above.

[0069] Finally, the second heat exchanger 312 can be turned off so that its temperature increases, thus capturing the CO2 present in frozen form within this second heat exchanger 312, which can then melt to be stored in liquid form and at high pressure.

[0070] Finally, Figure 5 is a cutaway view of a vessel 70 showing a tank 200 containing gas in liquid and gaseous states, said tank 200 being generally prismatic in shape and mounted within the vessel's double hull 72. This tank 200 may be part of an LNG vessel, but it may also be a reservoir if the gas is used as fuel for a fuel consumer.

[0071] The wall of the tank 200 comprises a primary sealing membrane intended to be in contact with the gas in liquid state contained in the tank, a secondary sealing membrane arranged between the primary sealing membrane and the double hull 72 of the vessel 70, and two insulating barriers arranged respectively between the primary sealing membrane and the secondary sealing membrane and between the secondary sealing membrane and the double hull 72.

[0072] Loading and / or unloading pipes 73 located on the upper deck of the vessel can be connected by suitable connectors to an offshore or port terminal for transferring a cargo of gas in liquid state from or to the tanks 200, such as liquefied natural gas, liquefied petroleum gas, heavy fuel oil, extra low sulfur fuel oil, diesel, methanol, or leaded or unleaded gasoline.

[0073] FIG. 5 also shows an example of a marine terminal with a loading and / or unloading station 75, an underwater duct 76, and an onshore facility 77. The loading and / or unloading station 75 is a fixed offshore facility with a moving arm 74 and a tower 78 that supports the moving arm 74. The moving arm 74 carries a bundle of insulated pipes 79 that can be connected to the loading and / or unloading pipes 73. The adjustable moving arm 74 fits all vessel sizes. The loading and unloading station 75 allows the loading and / or unloading of the vessel 70 from or to the onshore facility 77. Said facility has a liquefied gas storage tank 80 and a connecting duct 81 connected to the loading or unloading station 75 by an underwater duct 76. The underwater duct 76 allows the transfer of liquefied gas between the loading or unloading station 75 and the onshore facility 77 over long distances, for example 5 km, which makes it possible to keep the vessel 70 at a long distance from the shore during the loading and / or unloading operations.

[0074] To generate the pressure required for the transport of liquefied gas, one or more unloading pumps carried by the tower are used to load and / or unload the tanks 200, and / or pumps provided at the onshore facility 77, and / or pumps provided at the loading and unloading stations 75.

[0075] Naturally, the invention is not limited to the examples just described, and many variations can be made to these without departing from the scope of the invention.

[0076] The invention therefore provides a device for treating exhaust gases emitted by fuel consuming devices, in particular gas consuming devices of ships, such as ship propulsion engines, which makes it possible to significantly reduce the concentration of carbon dioxide present in these exhaust gases before they are released into the atmosphere.

[0077] However, the invention may not be limited to the means and configurations described and illustrated herein, but extends to any equivalent means or configurations, and any combination of the technical uses of such means. In particular, the shape and arrangement of the cooling means, heating means and compression members may be modified without impairing the invention, so long as they perform the functions described in this document.

Claims

1. A device (300) for treating at least a part of the exhaust gas discharged by at least one fuel consumption device (101), the treatment device (300) comprising at least one compression member (320) designed to increase the pressure of at least a part (FE1) of the exhaust gas discharged by the fuel consumption device (101), and at least one unit (310) for capturing carbon dioxide present in the exhaust gas (FE1), the compression member (320) and the unit (310) for capturing carbon dioxide (CO ２ ) are arranged between the fuel consumption device (101) and the turbocharger (120), the turbine (122) of the turbocharger is designed to be powered by exhaust gas (FE2, FE3), and the compressor (121) of the turbocharger is designed to supply an oxidant to the fuel consumption device (101), the treatment device (300).

2. At least one cooling means (301) designed to cool the exhaust gas (FE1) discharged by the fuel consumption device (101) upstream of the unit (310) for capturing carbon dioxide, and at least one heating means (302) designed to heat the exhaust gas (FE1) downstream of the capture unit (310). The processing device (300) according to claim 1.

3. The concentration of carbon dioxide (CO ２ ) in the exhaust gas (FE) discharged by the fuel consumption device (101) is designed to be reduced by up to 80%, and the processing device (300) according to claim 1 or 2 is characterized in that.

4. The unit (310) for capturing the carbon dioxide (CO ２ ), an absorption device (331) suitable for at least a portion of the exhaust gas (FE1) exiting through the compression member (320), wherein the absorption device (331) contains a solvent (S ２ ), S ＋ＣＯ２ ), S －ＣＯ２ ) designed to capture the carbon dioxide (CO) present in the exhaust gas (FE1), and is disposed on a solvent circuit (330) through which the solvent circulates. The processing device (300) according to claim 1 or 2, comprising an absorption device (331).

5. The solvent circuit (330) includes at least the absorption device (331), a member (333) for circulating the solvent, and at least one member (332) for regenerating the solvent designed to allow the captured carbon dioxide (CO ２ ) to be removed from the solvent, at least a first heat exchanger (334) designed to exchange heat between the solvent (S ＋ＣＯ２ ) filled with carbon dioxide and the solvent (S －ＣＯ２ ) from which the carbon dioxide has been removed, and at least a second heat exchanger (335) designed to cool the solvent (S －ＣＯ２ ) upstream of the absorption device (331) with respect to the circulation direction of the solvent in the solvent circuit (330). The processing device (300) according to claim 4.

6. The unit (310) for capturing carbon dioxide (CO ２ ) comprises at least a first heat exchanger (311) suitable for exchanging heat between a refrigerant (FR) and a gas withdrawn from a tank (200) in a liquid state, and at least a second heat exchanger (312) suitable for exchanging heat between the refrigerant (FR) cooled by its passage through the first heat exchanger (311) and at least a part of the exhaust gas (FE1). The processing device (300) according to claim 1 or 2, comprising at least one refrigerant circuit (FR) in which the heat exchangers are arranged.

7. A system (100) for supplying gas to at least one fuel consumption device, wherein the supply system (100) includes at least one tank (200) containing gas in a liquid state and a gas state, at least one line (110) for supplying gas to the fuel consumption device (101), and at least one turbocharger (120) designed to supply an oxidant to the fuel consumption device (101). And at least one device (300) for processing the gas according to claim 1 or 2, wherein the gas supply line (110) includes at least one heat exchanger (111) designed to evaporate the gas taken out from the tank (200) in a liquid state, and at least one compression device (112) suitable for raising the pressure of the gas to a pressure suitable for the requirements of the fuel consumption device (101). A system (100).

8. A method for processing exhaust gas (FE) discharged by a fuel consumption device (101) using at least one device (300) for processing exhaust gas according to claim 1 or 2, wherein at least Separating the exhaust gas (FE) discharged by the fuel consumption device (101) into a first portion (FE1) of the exhaust gas and a second portion (FE2) of the exhaust gas; Supplying the first portion (FE1) of the exhaust gas to a compression member (320); Compressing the first portion (FE1) of the exhaust gas by the compression member (320); A step of supplying the first portion (FE1) of the compressed exhaust gas to a unit (310) for capturing carbon dioxide (CO ２ ); Carbon dioxide (CO ２ ) is captured by the unit (310) to recover carbon dioxide (CO ２ ) present in the first portion (FE1) of the exhaust gas; Mixing the first portion (FE1) of the exhaust gas exiting the unit (310) for capturing carbon dioxide with the second portion (FE2) of the exhaust gas to form a mixed gas (FE3); Supplying the mixed gas (FE3) to a turbocharger (120); The step of cooling the mixed gas (FE3) exiting the turbocharger (120); The step of discharging the cooled mixed gas (FE3) to the atmosphere; A method comprising the above.

9. The method for treating exhaust gas according to claim 8, wherein the first portion (FE1) of the exhaust gas and the second portion (FE2) of the exhaust gas are different from each other.

10. The method for treating exhaust gas according to claim 8, wherein the first portion (FE1) of the exhaust gas represents 10% to 90% of all of these exhaust gases (FE), and the second portion (FE2) of the exhaust gas represents 90% to 10% of all of these exhaust gases (FE).

11. A ship (70) for transporting liquefied gas, comprising at least one fuel consumption device (101) and at least one device (300) for treating at least a portion of the exhaust gas (FE) discharged by the fuel consumption device (101) according to claim 1 or 2.

12. A system (100) for loading or unloading liquid gas, comprising a system (100) combining at least one onshore facility (77) and at least one ship (70) for transporting liquid gas according to claim 11.

13. A method for loading or unloading liquid gas from the gas carrier (70) according to claim 11.

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