Carbon dioxide storage tank

Abstract

The invention relates to a tank (10) for storing solid-state carbon dioxide, comprising: - an opening (11) in the upper part of the tank, through which a flow of gaseous-state carbon dioxide is likely to escape; - a device (12) for sealing the opening (11), which is able to move between a sealed position (13), in which the entire opening (11) is sealed, and an open position (14), in which at least one portion (14') of the opening is free, and vice versa; and - at least one dilution member (15) which is arranged near the opening (11) and is intended to generate a flow of gas, preferably air, so as to dilute the flow of gaseous-state carbon dioxide.

Description

Title of the invention: Carbon dioxide storage tank

[0001] The present invention relates to the field of treatment of a gas in the solid state such as carbon dioxide, and more particularly concerns a tank capable of storing a cargo of said gas, preferably in the solid state.

[0002] Currently, a new supply chain for processing a gas such as carbon dioxide is being developed. This chain involves an initial phase of gas capture, a second phase of gas transportation, for example within the tank of an entity such as a floating structure, and a final phase of gas burial at sites far removed from the capture sites.

[0003] The transport phase of carbon dioxide is optimal when it is in a solid state, particularly when it comes to maritime transport. At atmospheric pressure, carbon dioxide is in a solid or vapor state. In its solid state, the gas can be stored and handled at atmospheric pressure, while in its liquid state, its storage and handling can only be done at a pressure greater than 5.2 bar.

[0004] A problem arises during the carbon dioxide unloading stage. Indeed, there are a variety of methods for unloading bulk cargo in powder, granular, or block form from the tank. Typically, to reduce the cost of unloading bulk carriers or container ships, unloading facilities are located at terminals so that their use can be shared with all other ships unloading their cargo. The ships' holds are opened for unloading. The unloading solutions available at terminals are used to unload the tanks in the open air.

[0005] This type of unloading solution is not suitable for volatile and potentially toxic cargo. However, at atmospheric pressure, solid carbon dioxide sublimates at room temperature and is toxic above a certain concentration. Sublimated carbon dioxide is therefore likely to create a lethal atmosphere in the tank environment. During the unloading phase, care must therefore be taken to minimize the sublimation of solid carbon dioxide, i.e., to limit any heat exchange at the solid / gas interface of the solid carbon dioxide. In addition, it is important to keep the concentration of gaseous carbon dioxide in the tank environment low. storage.

[0006] It should be remembered that outdoor air naturally contains carbon dioxide, approximately 0.04%, or 415 ppm by volume. Above a certain concentration in the air, carbon dioxide is dangerous or even fatal due to cardiovascular risks and the risk of asphyxiation. In the European Union and the United States, occupational exposure limits for eight hours of work are 5000 ppm, or a concentration of 0.5% (Directive 91 / 322 / EC for the European Union, and ACGIH (American Conference of Governmental Industrial Hygienists) in the United States). Limit values ​​for short exposure periods can also be defined. For example, this ACGIH limit is 30,000 ppm, corresponding to the weighted average concentration over 15 minutes.Finally, the value of 40,000 ppm was retained in the United States as an immediately dangerous concentration for life and health (“Immediately Dangerous to Life and Health Concentration” or IDLH).

[0007] There are unloading devices that operate by flowing the cargo to the bottom of the tank via a conveyor arm connected to the lower part of the tank and ensuring a transfer in a closed environment. Although meeting the cargo containment criterion, such a solution is not feasible with carbon dioxide because the latter forms aggregates when packaged in bulk in an enclosed, non-refrigerated space. It is therefore necessary to provide a disaggregation device to be able to flow the carbon dioxide in order to extract it from the tank.

[0008] The invention aims to overcome all or part of the problems mentioned above by proposing a solid-state carbon dioxide storage tank making it possible to maintain in the environment near the tank an atmosphere with a low concentration of gaseous carbon dioxide during the discharge of the solid-state carbon dioxide, while limiting the heat input to the solid-state carbon dioxide.

[0009] To this end, the invention relates to a tank for storing carbon dioxide in the solid state comprising an opening extending along a first plane, preferably horizontal, in the upper part of the tank through which a flow of carbon dioxide in the gaseous state is likely to escape, a device for closing the opening capable of moving between a closing position in which the entire opening is closed and an open position in which at least a portion of the opening is free, and vice versa. According to the invention, the tank comprises at least at least one dilution member arranged near the opening intended to generate a flow of gas, preferably air, so as to dilute the flow of carbon dioxide in the gaseous state.

[0010] Advantageously, the gas flow is generated along a first axis perpendicular to the first plane.

[0011] Advantageously, the tank of the invention comprises a first device for controlling the flow rate of the gas flow generated as a function of wind conditions blowing above the opening or a measurement of a carbon dioxide concentration in the ambient air near the opening of the tank.

[0012] According to one embodiment, the closure device comprises at least one closure panel, the at least one closure panel covering the entire opening in the closure position and uncovering the at least a portion of the opening in the open position.

[0013] Advantageously, the closing device comprises a device for setting the at least one closing panel in relative motion relative to the opening so as to move from the closing position to the open position, and vice versa, by activating the setting device in motion.

[0014] Advantageously, the at least one dilution member is movable in translation along the opening.

[0015] In another embodiment of the invention, the tank comprises a second device for controlling the translational movement of the at least one dilution member as a function of the open position of the closure device.

[0016] Advantageously, the tank comprises at least one carbon dioxide detector disposed near the opening configured to measure a carbon dioxide concentration in the ambient air near the opening of the tank.

[0017] Advantageously, the tank further comprises an alarm device configured to initiate corrective action if one of the at least one carbon dioxide detector measures a carbon dioxide concentration in the ambient air near the opening of the tank greater than a predetermined threshold.

[0018] The invention also relates to a floating structure comprising a hull forming a supporting structure and such a tank secured to said supporting structure.

[0019] The invention also relates to an unloading assembly for such a floating structure, comprising a carbon dioxide unloading device intended to plunge through the opening of the tank when the closure device is in the open position.

[0020] Advantageously, the carbon dioxide discharge device is configured to plunge in line with the opening when the shutter device is in the open position.

[0021] The invention also relates to a method for unloading such a solid-state carbon dioxide storage tank, the method comprising: a. A first step of placing the closure device in the open position; b. Prior to, or concomitantly with, the first step, a second step of generating the gas flow by the at least one dilution member; c. A third step of unloading the solid-state carbon dioxide.

[0022] Advantageously, the unloading method comprises, prior to at least one of the first and / or second steps, a step of bringing the tank to atmospheric pressure.

[0023] These and other features and advantages of the present invention will become more apparent from the following description, made with reference to the accompanying drawings, given as non-limiting examples, and in which:

[0024] [Fig.l] Figure 1 schematically represents a floating structure comprising a solid state carbon dioxide storage tank according to the invention, the opening of which is closed;

[0025] [Fig. 2] Figure 2 schematically represents a floating structure comprising a solid-state carbon dioxide storage tank according to the invention, the opening of which is partially open;

[0026] [Fig. 3] Figure 3 represents a sequence of the method of unloading a solid state carbon dioxide storage tank according to the invention;

[0027] [Fig. 4] Figure 4 illustrates the simulation results of the velocity contour at the tank level for four different configurations;

[0028] [Fig. 5] Figure 5 represents the simulation results of the evolution of the heat flux exchanged at the solid / gas interface of carbon dioxide in the solid state for the four different configurations;

[0029] [Fig. 6] Figure 6 illustrates an unloading terminal accommodating a floating structure according to the invention.

[0030] For the sake of clarity, the same elements will have the same references in the different figures.

[0031] Figure 1 schematically represents a floating structure 100 comprising a tank storage tank 10 for solid-state carbon dioxide 8 according to the invention, the opening of which is closed. In FIG. 1, the solid-state carbon dioxide is shown as being stored in the tank in the form of solid blocks. However, it does not depart from the scope of the invention if the carbon dioxide is stored in the tank in bulk or in another solid form.

[0032] The storage tank 10 for carbon dioxide in the solid state 8, which is the subject of the invention, comprises an opening 11 extending along a first plane PI, preferably horizontal, in the upper part of the tank. When carbon dioxide in the solid state is stored in the tank, it is likely to sublime and change state to pass, in part, to the gaseous state. A flow of carbon dioxide in the gaseous state is thus likely to escape through the opening 11 when the latter is open.

[0033] The storage tank 10 comprises a device 12 for closing the opening 11, capable of moving between a closing position 13 in which the entire opening is closed and an open position 14 in which at least a portion 14' of the opening is free, and vice versa. In other words, in the closing position, the tank is said to be closed and in the open position, the tank is at least partially open.

[0034] Finally, the storage tank 10 comprises at least one dilution member 15 arranged near the opening 11 intended to generate a gas flow so as to dilute the flow of carbon dioxide in the gaseous state. The flow of carbon dioxide in the gaseous state which would escape through the opening 11 is therefore mixed with a gas flow initiated by the at least one dilution member 15. The pocket of carbon dioxide in the gaseous state thus has a diluted carbon dioxide concentration. Preferably, the gas is the surrounding air. Preferably the dilution member(s) are fans. In the description which follows, we will use the term fan to designate the dilution member. Nevertheless, the invention is not limited to this embodiment and includes other variants to ensure the dilution of the carbon dioxide in the gaseous state.Another example of a dilution member may be an eductor, or mixing nozzle, operating according to the venturi principle by sucking in the surrounding fluid. Such an eductor may be connected to a flow of compressed air. Alternatively, the dilution member may be one or more jets of compressed air ensuring the dilution of the carbon dioxide in the gaseous state. Finally, in the following, the invention is described with the example of the fan as a dilution member generating an air flow from the surrounding air. This configuration has the advantage of using the surrounding air. available. However, it should be noted that it is not outside the scope of the invention to use another gas, for example nitrogen, which would have the same dilution role as air as described below. The use of nitrogen as a dilution gas is advantageously coupled with a check of the local oxygen level to ensure that the latter is not too low for safety reasons. Alternatively, it is also possible to use liquid air which would be vaporized.

[0035] The at least one dilution member 15 (we will refer hereinafter, in a non-limiting manner, to a fan) is arranged close to the opening 11, for example connected to an edge of the opening or spaced a few centimeters or decimeters from the opening in the first plane PI.

[0036] Preferably, the fan(s) 15 are positioned close to the opening 11, between the opening and the quay or a second floating structure to which the floating structure is attached. The fan(s) 15 thus ensure that the hazardous environment on the quay of the floating structure or on the second floating structure receives little, or no, carbon dioxide in the gaseous state.

[0037] In a preferred embodiment, the air flow is generated along a first axis 16 perpendicular to the first plane PI. The advantages resulting from this will be explained below.

[0038] In Figure 1, the closure device 12 is in the closure position (the opening 11 is in the closed position). The closure device 12 comprises at least one closure panel 21. Thus, it is understood that the at least one closure panel 21 covers the entire opening 11 in the closure position 13 and uncovers at least a portion of the opening in the open position 14.

[0039] In Figures 1, 2 and 3, the closed position, or closing of the tank, is achieved by wedge panels that are partitioned along the axis transverse to the ship. The open position is obtained when the panels are slid on the PI plane but along an axis transverse to the ship's axis. This is a schematic representation for illustrative purposes. The panels can also be partitioned along the longitudinal axis or even along several axes. And they can also slide along a longitudinal axis.

[0040] Figure 2 schematically represents a floating structure comprising a solid-state carbon dioxide storage tank according to the invention, the opening 11 of which is partially open. The portion 14' of the opening is free, that is to say that the opening 11 is open at the level of the portion 14'.

[0041] Advantageously, the closure device 12 comprises a device 22 for moving the at least one closure panel 21 relative to the opening 11 so as to move from the closure position 13 to the open position 14, and vice versa, by activating the movement device. The movement device 22 thus makes it possible to slide the panels 21, or to retract or fold them onto each other according to the configuration envisaged. Alternatively, it is also possible to move from the closure position 13 to the open position 14, and vice versa, by moving the panels 21 by means of a crane positioned at the quayside or on the second floating structure. This may in particular be the crane intended to unload the carbon dioxide in the solid state. By way of non-limiting example, the closure device 12 of FIG. 2 comprises two closure panels 21 connected by a pivot connection.The free portion 14' of the opening 11 is obtained by rotating one panel relative to the other. In the open position 14, the two panels 21 are superimposed on each other.

[0042] Alternatively, rails may be arranged on either side of the opening 11, and the at least one closing panel is configured to cooperate with the rails so as to move from the closed position to the open position, and vice versa, by translation along the rails.

[0043] Figure 2 also shows an unloading assembly for the floating structure 100. This assembly comprises a carbon dioxide unloading device 30 intended to dive through the opening 11 of the tank when the closure device is in the open position 14. The unloading device 30 may be, for example, an arm equipped with a cutter (which breaks up the solid matter) and a mechanical or pneumatic conveying device in the case of carbon dioxide stored in bulk. It may also be of the crane type for gripping a gripping device holding a block of carbon dioxide. As mentioned previously, the unloading device may in this case be used to retract the panels to move between the closure position and the open position of the tank opening.As seen in Figures 1 and 2, the unloading device 30 is conventionally brought to the level of the opening 11 by the deployment of an arm 31 of a tower 33 by means of the connection 32.

[0044] Advantageously, the carbon dioxide discharge device 30 is configured to plunge in line with the opening 11 when the closure device 12 is in the open position 14. In other words, the closure device 12 is in open position 14 to the right of the carbon dioxide discharge device 30. This feature makes it possible to open only the part of the tank intended to be discharged, thus limiting the possibilities of carbon dioxide in the gaseous state flowing out of the tank.

[0045] Figure 3 represents a sequence of the method for unloading a solid-state carbon dioxide storage tank according to the invention. The method for unloading the solid-state carbon dioxide storage tank comprises: a. A step 200 of docking or coupling a second floating structure of the floating structure 100. At this step, the closure device 12 is in the closure position 13 (the tank is closed). b. A step 201 of deploying the arm 32, in order to initiate the unloading of the solid-state carbon dioxide stored in the tank. c. A step 203 of placing the closure device in the open position. The opening 11 is thus partially open to allow the unloading of the cargo. d. Prior to, or concomitantly with, step 203, a step 202 of generating the air flow by the at least one fan 15. In FIG. 3, step 202 of generating the air flow takes place before step 203 of opening the tank.This configuration ensures that no pockets of gaseous carbon dioxide are released into the tank environment. e. A step 204 for unloading solid carbon dioxide. The unloading device 30 plunges through the portion 14' of the opening 11 to access the solid carbon dioxide cargo.

[0046] Such an unloading process ensures a low concentration of gaseous carbon dioxide in the tank environment during unloading.

[0047] If the tank is capable of being able to increase pressure, the unloading method of the invention comprises, prior to at least one of the steps 200, 201, 202, 203, a step of bringing the tank to atmospheric pressure, either by progressive dilution of the carbon dioxide in a mast (in the approach phase for example), or possibly by re-solidification or liquefaction of the carbon dioxide in the gaseous state.

[0048] Figure 4 illustrates the simulation results of the velocity contour at the tank for four different configurations. Figure 5 shows the simulation results of the evolution of the heat flux exchanged at the solid / gas interface of carbon dioxide in the solid state for the four different configurations (x-axis = time in seconds, y-axis = flux in watts).

[0049] The velocity contour simulation results are intended to illustrate the dispersion of gaseous carbon dioxide when the tank is opened and / or released by sublimation during unloading. Darker areas indicate higher velocities compared to lighter areas. Specifically, the results show the dispersion of gaseous carbon dioxide released by sublimation generated by convection with ambient air and solar radiation during cargo unloading.

[0050] For these simulations, it was considered that the floating structure extends parallel to the quay or to the second floating structure as illustrated in figures 1 and 2. In figure 4, we see a cross-sectional view of the floating structure and a tank. Only the gaseous sky of the tank is represented. In these simulations, carbon dioxide in the solid state in bulk was considered (we therefore see a dome shape of solid carbon dioxide under the gaseous sky) and, depending on the configurations, an air flow is generated by one or more dilution devices (fan(s)).

[0051] The four different configurations shown in Figure 4 correspond to wind conditions and fan positions as follows: a. Configuration A: no wind, no fan on the sea side (left of the figure), one fan on the quay side (right of the figure), airflow generated horizontally b. Configuration B: no wind, no fan on the sea side, one fan on the quay side, airflow generated inclined at 30° to the foreground c. Configuration C: 0.5 m / s wind (directed from the sea towards the quay, i.e. from left to right in the figure), no fan on the sea side, one fan on the quay side (airflow generated vertically) d. Configuration D: 0.5 m / s wind (directed from the sea towards the quay), one fan on the sea side (airflow generated vertically), one fan on the quay side (airflow generated vertically)

[0052] These simulations made it possible to highlight the impact of the flow generated by the fans on the propagation of carbon dioxide and on the flow exchanged at the solid / gas interface of carbon dioxide in the solid state.

[0053] As a reminder, the shape of the solid / gas interface is rounded. The velocity contours show in configurations A and B that the airflow generated by the fan is attracted by this interface. This can be seen in the velocity profile which has a maximum value in the tank, at the solid / gas interface (configuration A) or just above the tank opening (configuration B). The 30° upward inclination of the airflow generated by the fan (configuration B) does not prevent the phenomenon from occurring. This results in an exchanged flux of around 30000 W / m (see figure 5. Note that since these are calculations based on a 2D model, the unit is W / m). These two configurations meet the criterion of low concentration of carbon dioxide in the gaseous state in the environment, but promote the heat exchange between the ambient air and the carbon dioxide in the solid state in the tank.

[0054] Fan configuration D results in mutual attraction of the vertical jets, which generates vortices at the solid / gas interface. These vortices are illustrated by the high velocity contours. This results in a heat flux oscillating between 10000 W / m and 40000 W / m (see Figure 5). This configuration ensures a low level of gaseous carbon dioxide near the tank. However, this configuration is not optimal in terms of the exchanged flux at the solid / gas interface of carbon dioxide.

[0055] Configuration C shows that the flux exchanged at the solid / gas interface is limited (less than 5,000 W / m). As can be seen from the high velocity contour directed vertically from the fan, this configuration directs the gaseous carbon dioxide flow vertically, allowing its vertical dilution in the ambient air. This configuration ensures a low concentration of gaseous carbon dioxide in the tank environment, while limiting the heat exchange at the solid / gas interface of the cargo.

[0056] It appears that the presence of at least one fan 15 arranged near the opening 11 intended to generate an air flow, preferably vertical, so as to dilute the flow of carbon dioxide in the gaseous state allows the dilution in the ambient air of the carbon dioxide in the gaseous state which escapes from the tank during unloading.

[0057] Preferably, the air flow generated by the at least one fan 15 is vertical to allow better dilution of the gas. This configuration makes it possible to guarantee a low level of carbon dioxide concentration above the platform while limiting the flow exchanged between the carbon dioxide in the gaseous state present in the gaseous ceiling of the tank and the carbon dioxide in the solid state in the tank.

[0058] Thus, a vertically generated air flow makes it possible both to limit the exchanged flow at the solid / gas interface of the carbon dioxide in the tank, and also to dilute the carbon dioxide in the gaseous state in the ambient air. The object of the invention makes it possible to maintain in the environment near the tank an atmosphere with a low concentration of carbon dioxide in the gaseous state during the discharge of the carbon dioxide in the solid state, while limiting the heat input to the carbon dioxide in the solid state.

[0059] Figure 6 illustrates an unloading terminal accommodating a floating structure 100 according to the invention. The floating structure 100 comprises a hull 101 forming a supporting structure and a tank 10 as described previously, secured to said supporting structure 101.

[0060] In Figure 6, three fans 15 per opening 11 are shown schematically. This is an example. The invention relates to all configurations, with more than three or fewer than three fans 15 per opening. The number of fans 15 may in particular depend on the size of the opening and the power of each fan.

[0061] In a variant of the invention, the fans 15 can be movable in translation along the opening 11. They can be arranged on rails extending parallel to an edge of the opening and translate along the open portion 14' of the opening 11. This configuration makes it possible to limit the number of fans. In addition, the tank of the invention can comprise a second device 40 for controlling the translational movement of the at least one fan 15 as a function of the open position 14 of the closure device 12.

[0062] Advantageously, the tank according to the invention may further comprise a first device for controlling the flow rate of the air flow generated as a function of wind conditions blowing above the opening or a measurement of a carbon dioxide concentration in the ambient air near the opening 11 of the tank. The wind conditions may be measured by dedicated instrumentation on board the floating structure or at the quayside and / or transmitted by a weather station. They may also be wind conditions derived from weather predictions.

[0063] Advantageously, the storage tank according to the invention comprises at least one carbon dioxide detector 50 arranged near the opening 11 and configured to measure a carbon dioxide concentration in the ambient air near the opening 11 of the tank. The at least one detector 50 makes it possible to check the content in carbon dioxide in the tank environment and thus to check that this content is well below the required threshold. The flow rate of the air flow can thus be controlled according to the concentration of carbon dioxide in the ambient air measured by the detector 50.

[0064] Advantageously, the storage tank according to the invention may further comprise an alarm device 60 configured to initiate a corrective action if one of the at least one carbon dioxide detector 50 measures a carbon dioxide concentration in the ambient air near the opening of the tank greater than a predetermined threshold. The corrective action may be at least one of: a. Placing the closure device 12 of the opening 11 in the closure position; b. Spraying liquid nitrogen into the tank; c. Increasing the flow rate of the airflow generated by the fan(s).

[0065] Advantageously, the storage tank 10 of the invention is a sealed and thermally insulating tank comprising at least one wall comprising at least one thermally insulating panel intended to rest, directly or indirectly, against the supporting structure. This characteristic makes it possible to maintain the carbon dioxide in the solid state for as long as possible in the tank, whatever the external conditions, in particular temperature. In other words, said wall makes it possible to reduce the rate of transformation of carbon dioxide in the solid state into carbon dioxide in the gaseous state.

[0066] Although the invention has been described in connection with several particular embodiments, it is obvious that it is in no way limited thereto and that it includes all technical equivalents of the means described as well as their combinations if these fall within the scope of the invention.

[0067] The use of the verb "comprise", "comprise" or "include" and its conjugated forms does not exclude the presence of other elements or other steps than those set out in a claim.

[0068] In the claims, any reference sign in parentheses cannot be interpreted as a limitation of the claim.

[0069] It will more generally appear to those skilled in the art that various modifications can be made to the embodiments described above, in light of the teaching which has just been disclosed to them. In the following claims, the terms used should not be interpreted as limiting the claims to embodiments set forth in this description, but should be interpreted to include all equivalents which the claims are intended to cover by their wording and the prediction of which is within the reach of those skilled in the art based on their general knowledge.

Claims

Claims

1. Storage tank (10) for carbon dioxide in the solid state (8), characterized in that it comprises: a. an opening (11) extending along a first plane (PI), preferably horizontal, in the upper part of the tank through which a flow of carbon dioxide in the gaseous state is likely to escape, b. a device (12) for closing the opening (11) capable of moving between a closing position (13) in which the entire opening is closed and an open position (14) in which at least a portion (14') of the opening is free, and vice versa, c. at least one dilution member (15) arranged near the opening (11) intended to generate a flow of gas in the ambient air, preferably air, so as to dilute the flow of carbon dioxide in the gaseous state in the ambient air.

2. Tank according to claim 1, in which the gas flow is generated along a first axis (16) perpendicular to the first plane (PI).

3. Tank according to claim 1 or 2, comprising a first device for controlling the flow rate of the gas flow generated as a function of wind conditions blowing above the opening or a measurement of a carbon dioxide concentration in the ambient air near the opening (11) of the tank.

4. Tank according to any one of claims 1 to 3, in which the closure device (12) comprises at least one closure panel (21), the at least one closure panel (21) covering the entire opening in the closure position (13) and uncovering the at least a portion of the opening in the open position (14).

5. Tank according to claim 4, in which the closure device (12) comprises a device (22) for setting in motion relative to the at least one closure panel (21) relative to the opening (11) so as to pass from the closed position (13) to the open position (14), and vice versa, by activation of the movement device.

6. Tank according to any one of claims 1 to 5, in which the at least one dilution member (15) is movable in translation along the opening (11).

7. Tank according to claim 6, comprising a second device (40) for controlling the translational movement of the at least one dilution member (15) as a function of the open position (14) of the closure device (12).

8. A tank according to any one of claims 1 to 7, comprising at least one carbon dioxide detector (50) disposed near the opening configured to measure a carbon dioxide concentration in the ambient air near the opening (11) of the tank.

9. A tank according to claim 8, further comprising an alarm device (60) configured to initiate corrective action if one of the at least one carbon dioxide detector measures a carbon dioxide concentration in the ambient air near the opening of the tank greater than a predetermined threshold.

10. Floating structure (100) comprising a hull (101) forming a supporting structure and a tank (10) according to any one of claims 1 to 9 secured to said supporting structure (101).

11. An assembly for unloading a floating structure (100) according to claim 10, comprising a device (30) for unloading carbon dioxide intended to plunge through the opening (11) of the tank when the closure device is in the open position (14).

12. Unloading assembly according to claim 11, in which the carbon dioxide unloading device (30) is configured to plunge in line with the opening (11) when the closure device (12) is in the open position (14).

13. A method of unloading a solid state carbon dioxide storage tank according to any one of claims 1 to 9, comprising: a. A first step (203) of placing the closure device (12) in the open position; b. Prior to, or concomitantly with, the first step (203), a second step (202) of generating the gas flow in the ambient air, preferably air, by the at least one dilution member (15); c. A third step (204) of discharging the carbon dioxide in the solid state.

14. Unloading method according to claim 13, comprising, prior to at least one of the first and / or second steps (202, 203), a step of bringing the tank to atmospheric pressure.

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