A device for mixing a gas in its solid state with a liquid stream

Abstract

The invention relates to a mixing device (40) for a gas in the solid state in a liquid stream (6), intended to be connected to an inlet (22) of a circuit on the one hand and to an outlet (21) of said circuit on the other hand to form a closed circuit in which the liquid stream (6) circulates in a loop, the mixing device comprising an inlet zone (50) extending along a first axis (X), the inlet zone comprising: A first main inlet (52) intended to receive the liquid stream (6) tangentially to the first axis (X); A second inlet (53) intended to introduce the gas in the solid state along an axis intersecting the first axis; An outlet (54) through which a mixture (33) composed of particles (32) of the gas in the solid state and the liquid stream (6) is intended to leave the inlet zone;the mixing device comprising a main outlet (55, 54) intended to be fluidly connected to the inlet (22) of the circuit and through which the mixture is intended to leave the mixing device, the particles of the mixture being uniformly distributed in the liquid flow as they pass through the main outlet. Figure 2;

Description

Title of the invention: Device for mixing a gas in the solid state in a liquid flow

[0001] The present invention relates generally to the field of mixing devices and more particularly to a device for mixing and homogenizing a gas in the solid state in a liquid flow. This invention can find its application in the field of melting a gas in the solid state, such as carbon dioxide.

[0002] Currently, a new logistics chain for processing a gas such as carbon dioxide is being developed. This chain involves a first phase of capturing the gas, a second phase of transporting this gas and a final phase of burying the gas at sites very far from the capture sites.

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

[0004] To bury this gas in sites very far from the capture sites, it is therefore necessary to use means which change the state of the gas to make it pass from the solid state to the supercritical state. The supercritical state is imposed for geological sequestration constraints.

[0005] Such a change of state of the gas requires passage through an intermediate phase. In particular, it is possible to change the solidified gas to the liquid state for transport before changing it to the supercritical state.

[0006] There are technical means for converting a gas from a solid state to a liquid state. However, these means are not suitable for the logistics chain mentioned above, particularly when it comes to carbon dioxide. Indeed, this chain involves considerable volumes of gas to be treated, according to a continuous process and the non-existence of carbon dioxide in the liquid state at a pressure below 5.2 bar. Furthermore, the treatment must respect environmental constraints and consume as little energy as possible. The technical means known to date do not allow these difficulties to be resolved.

[0007] The Applicant has already developed a device for treating gas by phase change, comprising a device for melting a gas in the solid state. The device for melting the gas in the solid state comprises a closed circuit in which the same gas as the gas in the solid state circulates in the liquid state and in a loop, the closed circuit comprising at least one inlet for receiving the gas in the solid state and an outlet through which a portion of the gas in the liquid state leaves the closed circuit, the fusion device comprising at least one heat exchanger which implements a heat exchange between the gas in the liquid state which circulates in a loop within the closed circuit and another fluid. The heat exchanger's role is to heat the liquid gas circulating within the closed circuit in order to melt the solid gas that has been continuously introduced into the closed circuit. The heat exchanger thus maintains the appropriate temperature conditions so that the gas circulating within the closed circuit remains in the liquid state.

[0008] The fusion device thus comprises a closed circuit which is configured to transform the gas in the solid state into a gas in the liquid state, by fusion.

[0009] In order to achieve the fusion of carbon dioxide particles in the solid state within a reasonable time and in a fusion device with industrially acceptable dimensions, it is necessary that the solid particles in the liquid flow initially have a relatively small characteristic dimension and that the mixture of the solid particles in the liquid flow is as homogeneous as possible.

[0010] It is known to supply carbon dioxide in the solid state in the form of longitudinal and continuous elements. However, there is no satisfactory solution making it possible, from these longitudinal and continuous elements, to obtain a homogeneous particle / liquid mixture with a view to the fusion of the particles in the liquid flow over a short distance and in a short time.

[0011] The invention aims to overcome all or part of the problems cited above by proposing a device for mixing a gas in the solid state in a liquid flow allowing, thanks to a judicious flow of the liquid flow, the destructuring of the gas in the solid state into particles and the homogenization of these particles in the liquid flow to allow their fusion in the liquid flow.

[0012] To this end, the invention relates to a device for mixing a gas in the solid state in a liquid flow, the mixing device being intended to be connected to an inlet of a circuit on the one hand and to an outlet of said circuit on the other hand to form a closed circuit in which the liquid flow circulates in a loop, the mixing device comprising an introduction zone extending along a first axis, the introduction zone comprising: - A first main inlet intended to receive the liquid flow tangentially to the first axis; - A second inlet intended to introduce the gas in the solid state along an axis intersecting the first axis; - An outlet through which a mixture composed of particles of the gas in the solid state and of the liquid flow is intended to leave the introduction zone; the mixing device further comprising a main outlet intended to be fluidically connected to the inlet of the circuit and through which the mixture is intended to leave the mixing device, the particles of the mixture being uniformly distributed in the liquid flow as it passes through the main outlet.

[0013] In a variant, the mixing device according to the invention further comprises at least one second main inlet intended to receive the second liquid flow tangentially to the first axis, the main inlets being preferentially distributed along the introduction zone.

[0014] In one embodiment of the invention, the mixing device comprises a homogenization zone arranged downstream of the introduction zone and extending along the first axis, the homogenization zone comprising: - an inlet fluidically connected to the outlet of the introduction zone and intended to receive the mixture from the introduction zone; - a device for homogenizing particles in the liquid flow arranged downstream of the inlet of the homogenization zone; - an outlet through which the mixture having passed through the homogenization zone is intended to leave the homogenization zone, the particles of the mixture being detached from the inner wall of the homogenization zone upon passing the outlet of the homogenization zone.

[0015] In a variant, the homogenization device comprises a deflector arranged on a portion of the inner wall of the homogenization zone, the deflector moving parallel to the first axis from a lower part to an upper part while having an increasing thickness.

[0016] In another variant, the homogenization device comprises a static mixer comprising a plurality of blades arranged in a staggered pattern and on either side of the first axis, each of the plurality of blades having a curved portion forming a flow channel for the mixture, the blades being oriented so that two successive flow channels have a distinct orientation around the first axis.

[0017] In another variant, the homogenization device comprises a first diaphragm configured to limit a first passage section of the mixture along the first axis.

[0018] In another variant, the homogenization device comprises a second diaphragm downstream of the first diaphragm, configured to limit a second passage section of the mixture along the first axis, at a distance from the first passage section.

[0019] In one embodiment of the invention, the mixing device comprises a zone for parallelizing the flow lines of the mixture arranged downstream of the homogenization zone and extending along the first axis, the parallelization zone

[0020]

[0021]

[0022]

[0023]

[0024]

[0025]

[0026] including: - an inlet fluidly connected to the outlet of the homogenization zone and intended to receive the mixture from the homogenization zone; - a device for parallelizing the flow lines of the mixture arranged downstream of the inlet of the parallelization zone; - an outlet through which the mixture having passed through the homogenization zone is intended to leave the parallelization zone, the particles of the mixture being uniformly distributed in the liquid flow as it passes through the outlet. In one variant, the parallelization device comprises at least one wall extending from the inlet to the outlet of the parallelization zone parallel to the first axis. In a variant of the invention, the section of the parallelization zone evolves from the exit section of the homogenization zone towards the exit section of the parallelization zone. The invention also relates to a method for mixing a gas in the solid state in a liquid flow of a closed circuit in which the liquid flow circulates in a loop, the method implementing a mixing device as mentioned previously and comprising the following steps: a. First step of introduction to the first main inlet of the liquid flow tangentially to the first axis, resulting in creation of a vortex flow around the first axis in the introduction zone; b. Second stage of introduction at the second inlet of the gas in the solid state, preferably in the form of longitudinal and continuous elements, along an axis intersecting the first axis; c. Third stage of destructuring the gas in the solid state into gas particles in the solid state so as to form a mixture in which the particles are distributed in the liquid flow. Advantageously, the mixing method according to the invention further comprises a step of detaching the particles of the mixture from the inner wall of the homogenization zone. Advantageously, the mixing method according to the invention further comprises a step of parallelizing the flow lines of the mixture in the parallelization zone so that the particles of the mixture are uniformly distributed in the liquid flow. In one embodiment of the mixing method according to the invention, the gas in the solid state and the liquid stream are carbon dioxide. These and other features and advantages of the present invention will become apparent more clearly from the following description, made with reference to the attached drawings, given as non-limiting examples, and in which:

[0027] [Fig.l] schematically represents a fusion device in which the mixing device according to the invention can be implemented;

[0028] [Fig.2] represents an embodiment of a mixing device according to the invention;

[0029] [Fig. 3] represents the current lines of the liquid flow in the introduction zone of the mixing device according to the invention;

[0030] [Fig.4] represents a variant of the introduction zone of the mixing device according to the invention;

[0031] [Fig.5] represents a first embodiment of the homogenization zone of the mixing device according to the invention;

[0032] [Fig.6] represents a second embodiment of the homogenization zone of the mixing device according to the invention;

[0033] [Fig.7] represents a third embodiment of the homogenization zone of the mixing device according to the invention;

[0034] [Fig.8] represents a fourth embodiment of the homogenization zone of the mixing device according to the invention;

[0035] [Fig.9] represents a first embodiment of the zone of parallelization of the current lines of the mixing device according to the invention;

[0036] [Fig. 10] represents a second embodiment of the zone of parallelization of the current lines of the mixing device according to the invention;

[0037] [Fig. 11] schematically represents the steps of a method of mixing a gas in the solid state in a liquid flow according to the invention.

[0038] For the sake of clarity, the same elements will bear the same references in the different figures.

[0039] 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.

[0040] This document uses the words upstream and downstream to define the relative arrangement of certain 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.

[0041] In the following, the mixing device according to the invention is described in the context of mixing and homogenizing carbon dioxide particles in the solid state in a liquid flow of carbon dioxide. As will appear from reading the description of the invention, the mixing device can be applied in a similar manner to other species, the liquid flow not necessarily being made up of the same species as the solid particles.

[0042] [Fig. 1] schematically represents a fusion device in which the mixing device according to the invention can be implemented. Such a fusion device 8 is responsible for changing a gas initially in the solid state 2 to the liquid state. The fusion device 8 comprises a closed circuit 12 in which a liquid flow (preferably the same gas as the gas in the solid state 2) circulates in a loop and in liquid form, in other words, a flow of gas in the liquid state 6. Such a flow is shown in dotted lines in [Fig. 1]. In the embodiment shown in [Fig. 1], the closed circuit 12 comprises at least one inlet 14 for receiving the gas in the solid state 2. This inlet 14 forms the zone through which the gas in the solid state 2 is introduced into the closed circuit 12. The closed circuit 12 also comprises an outlet 16 through which a portion of the flow of gas in the liquid state 6 exits. This fusion device 8 operates continuously.A flow of gas in the liquid state 6 rotates continuously within the closed circuit 12. A determined volume of gas in the solid state 2 is incorporated into this flow of gas in the liquid state 6 at a first point of the closed circuit 12, namely the inlet 14. A mass of gas flow in the liquid state 6 substantially identical to the mass of gas in the solid state 2 incorporated is extracted at a second point of the closed circuit 12, namely the outlet 16. The volume of gas in the liquid state 6 extracted is determined as a function of the level in the expansion tank 9 which controls the volume flow rate of the flow of gas in the liquid state 6 at the outlet 16 of the closed circuit 12. The volume of gas in the solid state 2 incorporated is controlled by a circuit outlet flow rate setpoint given by an operator.The expansion vessel 9 makes it possible to absorb the variations in the volume of gas in the liquid state 6 present within the closed circuit 12, during the start-up and shutdown phases, during fluctuations in the temperature of the mixture of gas in the liquid state and gas in the solid state and to balance the mass differences between the gas in the solid state which integrates the closed circuit 12 and the gas in the liquid state which is withdrawn at the outlet 16 of the closed circuit 12. In the case where the gas in the solid state 2 and the flow of gas in the liquid state 6 are carbon dioxide, the incorporated mass and the extracted mass represent a mass of between one tenth and one twelfth, preferably one eleventh, of the mass corresponding to the flow of gas in the liquid state present in the closed circuit 12.

[0043] The objective of such a fusion device is to obtain a constant volume of mixture of liquid gas 6 and solid gas 2 within the closed circuit as well as a good ho homogeneity of the mixture and a rapid and significant transmission of heat from the gas in the liquid state 6 to the gas in the solid state 2. The flow rate ratio makes it possible to maintain a significant temperature difference between the gas in the solid state 2 and the flow of gas in the liquid state 6 throughout the heat transfer leading to a maintenance of high heat transfer and consequently allowing faster fusion. Furthermore, maintaining the significant temperature difference between the gas in the solid state 2 and the flow of gas in the liquid state 6 makes it possible to avoid local freezing of the flow of gas in the liquid state 6 in contact with the gas in the solid state 2 within the closed circuit 12.

[0044] The melting device 8 advantageously comprises at least one heat exchanger 18 which implements a heat exchange between the flow of gas in the liquid state 6 which circulates in a loop within the closed circuit 12 and another fluid. This other fluid is for example glycol. The role of the heat exchanger 18 is to heat the flow of gas in the liquid state 6, in order to melt the gas in the solid state 2 mixed with the flow of gas in the liquid state 6 circulating within the closed circuit 12. The outlet 16 is configured to extract a portion of the flow of gas in the liquid state 6 previously heated by the heat exchanger 18.

[0045] The fusion device 8 comprises a circulation device 30, for example a pump, configured to ensure the movement of the flow of gas in the liquid state 6 within the closed circuit 12.

[0046] As illustrated in [Fig.l], the fusion device is configured so that the flow of gas in the liquid state 6 circulates in a counterclockwise direction within the closed circuit 12.

[0047] A portion of the flow of gas in the liquid state 6 not extracted from the closed circuit 12 continues its circulation within the closed circuit 12, thanks to the circulation device 30, according to a substantially horizontal flow in order to perpetuate the circulation of the flow of gas in the liquid state 6 within the closed circuit 12 and thus ensure a device whose operation is continuous.

[0048] The gas in the solid state 2 is introduced into the closed circuit 12 through the inlet 14. The gas in the solid state, generally in the form of longitudinal and continuous elements, must be decomposed into particles 32 and then mixed with the gas in the liquid state 6 circulating in the closed circuit. To achieve the destructuring of the gas in the solid state 2 into particles 32 and then the homogenization of the particles 32 in the liquid flow of gas in the liquid state 6, a mixing device 40 is advantageously integrated into the loop of the closed circuit 12. Such a mixing device 40 is the subject of the invention. It should be noted that the fusion device 8 has been described as a non-limiting example to illustrate a possible implementation of the mixing device of the invention.Obviously, the mixing device which is the subject of the invention can be applied in other configurations to deconstruct the gas in the solid state into particles, and to mix and homogenize the solid particles in a liquid flow.

[0049] [Fig.2] represents an embodiment of a mixing device according to the invention. The mixing device 40 of a gas in the solid state 2 in a liquid flow 6 is intended to be connected to an inlet 22 of a circuit 12 on the one hand and to an outlet 21 of the circuit 12 on the other hand to form a closed circuit 12 in which the liquid flow 6 circulates in a loop, as explained previously. The outlet 21 and the inlet 22 are named arbitrarily. They each respectively represent an inlet and outlet connection point for the mixing device 40 of the invention. The mixing device comprises an introduction zone 50 extending along a first axis X. In the description of the invention, a zone is to be understood as a portion of the mixing device. The introduction zone 50 comprises an inlet for the liquid flow 6 and an inlet for the gas in the solid state.More precisely, the introduction zone comprises at least a first main inlet 52 intended to be connected to the outlet 21 of the circuit 12 and to introduce the liquid flow 6. The main inlet 52 is therefore the inlet which allows the direct fluidic connection with the liquid flow circulating in a loop in the closed circuit 12. The introduction zone comprises a wall 49 substantially perpendicular to the first axis X. This wall 49 has a role of closing the introduction zone. Advantageously, this wall can be convex in shape, that is to say that it has a spherical curvature in relief, being rounded.

[0050] The introduction zone therefore comprises a first main inlet 52 intended to receive the liquid flow 6 tangentially to the first axis X. This liquid flow is therefore the same liquid flow as that which circulates in the closed circuit 12. This main inlet 52 is connected to an injection means 56 (here an injection channel oriented substantially perpendicular to the first axis X) of the liquid flow. This injection means 56 allows the tangential injection of the liquid flow into the introduction zone. This injection of the liquid flow tangentially is preferably carried out by means of a pipe with a reduced diameter in the introduction zone. This makes it possible to set up a swirling flow in the introduction zone. In other words, the injection means 56 has a diameter smaller than the section of the introduction zone. As a result, with the same liquid flow rate, a high circulation speed is ensured.

[0051] [Fig.3] represents the streamlines of the liquid flow in the introduction zone 50 of the mixing device according to the invention. A streamline is a curve in space describing the movement of the fluid, here the liquid flow, and which, at any instant, has at any point a tangent parallel to the speed of the particles of the fluid. The streamlines thus make it possible to observe the flow of the liquid flow.

[0052] Returning to [Fig.2], the introduction zone 50 comprises a second inlet 53 intended to introduce the gas in the solid state 2 along an axis secant to the first axis X. Gé Generally, the solid-state gas 2 is provided in the form of longitudinal and continuous blocks or elements. The combination of the introduction of the liquid flow at the inlet 52 ensures a swirling flow, i.e. the flow is mainly a rotational movement around the first axis X. This is also referred to as a vortex, it being understood that in the context of the invention, the diameter of the swirl formed is such that the swirl is obviously contained in the introduction zone. The inlet 53 is advantageously arranged downstream of the inlet 52. This ensures that the solid-state gas is introduced into the introduction zone 50 where the swirling flow is already developed. The solid-state gas is introduced via the inlet 53. It comes into contact with the liquid flow in the form of a swirl having a high circulation speed.When the solid gas comes into contact with the vortex, the solid gas is torn away or nibbled away by the liquid flow. In other words, it is deconstructed and passes from the state of a block (or continuous longitudinal element) to the state of pellets or particles 32. .

[0053] In the case where the gas in the solid state 2 and the liquid flow 6 are carbon dioxide, taking into account the differences in densities of the two phases involved (of the order of 800 kg / m3 in the case of the gas in the solid state compared to 956 kg / m3 for the liquid flow), the particles 32, once torn off, refocus along the first axis X of the pipe, whereas the liquid flow tends to be pressed against the walls under the effect of centrifugal force.

[0054] Finally, the introduction zone comprises an outlet 54 through which a mixture 33 composed of particles 32 of the gas in the solid state 2 and of the liquid flow 6 is intended to leave the introduction zone 50. For information purposes, the longitudinal and continuous elements of gas in the solid state may have a diameter of 2 mm. The particles 32 have a length of the order of 2 to 2.5 mm, for example 2.4 mm.

[0055] Furthermore, the mixing device 40 comprises a main outlet 55 intended to be fluidically connected to the inlet 22 of the circuit 12 and through which the mixture 33 of particles and liquid flow is intended to leave the mixing device 40. At the main outlet, the particles 32 of the mixture are uniformly distributed in the liquid flow as they pass through the main outlet.

[0056] As will be described below, the mixing device 40 may comprise, in different variants, other additional zones (homogenization zone 60 with its inlet 64 and its outlet 65, and / or zone for parallelization of the streamlines 70) to allow better homogenization of the particles 32 in the liquid flow. However, since the introduction zone alone ensures a good level of homogenization, the main outlet may be the outlet 54 corresponding to the outlet of the introduction zone.

[0057] After passing the main outlet of the mixing device, the mixture 33 continues the circulation through a branch 20 of the closed circuit 12. The particles 32 still present in the mixture 33 will merge during this circulation as detailed previously.

[0058] [Fig. 4] represents a variant of the introduction zone 50 of the mixing device 40 according to the invention. In this variant, the introduction zone comprises at least one second main inlet 52', associated with its injection means 56', intended to receive the liquid flow 6 tangentially to the first axis X. Preferably, the main inlets 52, 52' are distributed along the introduction zone 50 along an axis parallel to the first axis X. In [Fig. 4], two main inlets are illustrated. However, the invention applies in a similar manner to a plurality of main inlets along the length of the introduction zone.The plurality of main inlets makes it possible to guarantee both a sufficient supply of heat to avoid the formation of frost at the level of the introduction of the gas in the solid state and the maintenance of a good swirling flow in the introduction zone and the maintenance of a high flow speed around the periphery of the introduction zone, despite the introduction of the gas in the solid state via the inlet 53 which tends to reduce the flow speed near the inlet 53. In [Fig. 4], the main inlets 52, 52' are arranged next to each other along an axis Y parallel to the first axis X. However, it is not outside the scope of the invention to have a plurality of main inlets which would be distributed offset from each other around a section of the introduction zone.

[0059] In one embodiment of the invention, the mixing device comprises a homogenization zone 60 arranged downstream of the introduction zone 50 and extending along the first axis X. As can be seen in [Fig. 2], the homogenization zone 60 comprises an inlet 64 fluidly connected to the outlet 54 of the introduction zone and intended to receive the mixture 33 from the introduction zone 50. The homogenization zone 60 comprises an outlet 65 through which the mixture 33 having passed through the homogenization zone 60 is intended to leave the homogenization zone 60. Between the inlet 64 and the outlet 65, the homogenization zone comprises a homogenization device 67 intended to homogenize the particles 32 in the mixture 33. The particles 32 of the mixture are then detached from the inner wall of the homogenization zone at the exit 65 of the homogenization zone 60.Indeed, given the difference in density between the solid particles and the liquid flow, and the vortex flow set up, the particles are initially found mainly near the walls of the mixing device. The homogenization zone ensures as quickly as possible and over a short distance the homogeneity of the distribution of the particles 32 in the liquid flow. This results in a lower mass concentration of particles lo. caly, allowing faster melting of particles in the liquid flow. Similarly, the homogenization zone prevents the appearance of zones of refreezing of carbon dioxide in the form of larger particles downstream of the introduction zone.

[0060] [Fig. 5] represents a first embodiment of the homogenization zone 50 of the mixing device according to the invention. The upper illustration of [Fig. 5] is a transparent view and the lower illustration of [Fig. 5] is a sectional view orthogonal to the first axis X. In this embodiment, the homogenization device 67 comprises a deflector 61 arranged on a portion of the inner wall of the homogenization zone. The deflector 61 moves parallel to the first axis X from a lower part 61a to an upper part 61b, having an increasing thickness e.

[0061] Thanks to this variation of local section in the homogenization zone 60, the deflector 61 makes it possible to detach the particles blocked on the wall, disturbing the flow to a minimum. The deflector is placed in the direction of the rotation of the vortex flow and, preferably, on the direct path of the jet facing the third inlet 53, so as to disturb the zone with the highest concentration of particles. The deflector 61 makes it possible to bring some of the particles back towards the center of the homogenization zone.

[0062] [Fig. 6] represents a second embodiment of the homogenization zone of the mixing device according to the invention. In this embodiment, the homogenization device 67 comprises a static mixer 62 comprising a plurality of blades 62a, 62b arranged in a staggered manner and on either side of the first axis X, each of the plurality of blades having a curved portion 62c forming a flow channel for the mixture 33. The blades are oriented so that two successive flow channels have a distinct orientation (respectively denoted X+ and X-) around the first axis X. The static mixer 62 forces the flow to rotate successively in one direction then in the other, thus promoting good distribution of the particles in the liquid flow.

[0063] It may be noted that the homogenizing device 67 may comprise a deflector 61 and a static mixer 62 to combine the effects of each, or the homogenizing device may comprise only one of the two.

[0064] [Fig.7] represents a third embodiment of the homogenization zone of the mixing device according to the invention. In this embodiment, the homogenization device 67 comprises a first diaphragm 63 configured to limit a first passage section of the mixture along the first axis X. The diaphragm is an element which limits the flow of a fluid. In the context of the invention, the first diaphragm 63 constitutes a convergent which directs the flow towards the first axis X. In other words, the flow which was previously swirling near the walls tends to distribute the particles of the mixture 33 towards the walls. Thanks to the first diaphragm, the flow of the mixture 33 is refocused. The particles 32 are detached from the wall.

[0065] Flow simulations made it possible to observe the distribution of the particles 32 in the mixture at different distances upstream of the bend formed before the branch 20 (d1 is 1.5 m from the bend and 0.5 m from the first diaphragm, d2 is 1.0 m from the bend and d3 is at the inlet of the bend). At d1, it was possible to observe that the first diaphragm 63 made it possible to detach some of the particles, but the central zone is a little less concentrated in particles and many particles have stuck back to the wall. At d2, it was possible to observe that certain particles near the first axis X have melted. Finally, at d3, the melting of the particles near the first axis X has continued. It is nevertheless observed that certain particles have remained close to each other near the wall.

[0066] It follows that the diaphragm 63 makes it possible to bring some of the particles towards the center of the homogenization zone where they melt more quickly.

[0067] [Fig. 8] represents a fourth embodiment of the homogenization zone of the mixing device according to the invention. In this embodiment, the homogenization device 67 comprises a second diaphragm 66 downstream of the first diaphragm 63, configured to limit a second passage section of the mixture 33 along the first axis X, at a distance from the first passage section. The presence of the second diaphragm 66 in series with the first diaphragm makes it possible to bring the particles back to the center of the homogenization zone a first time, and allow them to melt there, then to bring back those remaining close to the wall.

[0068] It may also be noted that the homogenizing device 67 may comprise a deflector 61, a static mixer 62 and one or more diaphragms to combine the effects of each, or the homogenizing device may comprise only one or two of the three.

[0069] It must be kept in mind that the diaphragm(s) allow(s) to detach the particles from the wall to direct them towards the center of the homogenization zone. However, this detachment is carried out on a swirling flow. With a restriction of the passage section of such a flow, the particles are found to be distributed in a very homogeneous manner in the mixture 33 on a portion downstream of the homogenization zone. However, past this portion, they may find themselves more concentrated on another downstream portion of the section.

[0070] Although the embodiments of the mixing device described above already offer a very satisfactory solution in terms of homogenization of the particles in the mixture, a zone of parallelization of the streamlines of the mixture can be introduced in order to maintain an optimal distribution of particles in the mixture.

[0071] [Fig.9] represents a first embodiment of the zone of parallelization of the current lines of the mixing device according to the invention. In this embodiment, the mixing device 40 comprises a zone 70 for parallelizing the flow lines of the mixture, arranged downstream of the homogenization zone 60 and extending along the first axis X. The parallelization zone 70 comprises an inlet 74 fluidly connected to the outlet 65 of the homogenization zone 60 and intended to receive the mixture 33 from the homogenization zone 60. The parallelization zone 70 comprises an outlet 75 through which the mixture 33 having passed through the homogenization zone 60 is intended to leave the parallelization zone 70. Between the inlet 74 and the outlet 75, the parallelization zone 70 comprises a device 77 for parallelizing the flow lines of the mixture, arranged downstream of the inlet 74 of the parallelization zone 70.The flow lines of the mixture 33 downstream of the homogenization zone 60 being made parallel to each other, the particles 32 of the mixture are uniformly distributed in the liquid flow as they pass the outlet 75. Note that the outlet 75 corresponds in this embodiment to the outlet 55 of the mixing device 40.

[0072] In the embodiment shown in [Fig. 9], the parallelization device 77 comprises at least one wall 71, 72 extending from the inlet 74 to the outlet 75 of the parallelization zone 70 parallel to the first axis X. The wall or walls of the parallelization zone make it possible to straighten the flow of the mixture 33, that is to say to cause the mixture 33 to have a flow substantially parallel to the first axis X to stop the winding effect generated by the upstream swirling flow. As illustrated, the walls 71, 72 are perpendicular to each other and intersect along the first axis X. They thus form four parallel flow channels for channeling the flow of the mixture 33 in the parallelization zone. The parallelization device may also comprise several other walls, for example three or four.However, it is preferable to have a limited number of walls (preferably two) to maintain channels of sufficient width to avoid aggregation of particles 32. .

[0073] It is not outside the scope of the invention if the walls 71, 72 are parallel to each other and also form flow channels for the mixture 33.

[0074] In [Fig.9], the parallelization zone has a constant section along the first axis X. Such a section makes it possible to limit the recirculation zones of the flow of the mixture 33.

[0075] [Fig. 10] represents a second embodiment of the zone of parallelization of the current lines of the mixture of the mixing device according to the invention. In this embodiment, the section of the parallelization zone evolves from the outlet section 64 of the homogenization zone 60 towards the outlet section 75, of section su above section 64, of the parallelization zone 70. Such a flaring of the section of the parallelization zone makes it possible to gradually return from a lower section downstream of the diaphragm to a higher nominal section of the branch 20 to which the mixing device 40 is connected.

[0076] [Fig. 11] schematically represents the steps of a method for mixing a gas in the solid state in a liquid flow according to the invention. The method for mixing a gas in the solid state in a liquid flow of a closed circuit in which the liquid flow circulates in a loop uses the mixing device 40 as described previously. The method according to the invention comprises a first step 110 of introducing the liquid flow 6 at the first main inlet 52 tangentially to the first axis X. The step 110 results in the creation of a swirling flow around the first axis X in the introduction zone 50. The method comprises a second step 120 of introducing the gas in the solid state 2 at the second inlet 53, preferably in the form of longitudinal and continuous elements, along an axis intersecting the first axis X. The introduction of the gas in the solid state takes place downstream of the formation of the swirling flow.The gas in the solid state enters the introduction zone where a vortex flow is already established.

[0077] Finally, the method comprises a third step 130 of destructuring the gas in the solid state 2 into particles 32 of gas in the solid state 2 so as to form a mixture 33 in which the particles 32 are distributed in the liquid flow 6. The swirling flow formed thanks to the judicious combination of the injections of the liquid flow in step 110 has a destructuring effect on the gas introduced in the solid state. The winding of the liquid flow acts as a blade on the gas in the solid state. After its introduction at the second inlet, the gas in the solid state collides with the liquid flow swirl. This results in a decomposition of the gas in the solid state into a plurality of particles 32 which are distributed in the liquid flow 6 to form the mixture 33.

[0078] Advantageously, the mixing method according to the invention may further comprise a step 140 of detaching the particles 32 of the mixture 33 from the inner wall of the homogenization zone 60.

[0079] Advantageously, the mixing method according to the invention may further comprise a step 150 of parallelizing the flow lines of the mixture 33 in the parallelization zone 70 so that the particles 32 of the mixture are uniformly distributed in the liquid flow 6.

[0080] Although the invention has been described in connection with several particular embodiments, it is quite obvious that it is in no way limited thereto and that it includes all the technical equivalents of the means described as well as their combinations if these fall within the scope of the invention.

[0081] The use of the verb “comporter”, “comprendre” or “include” and its forms conjugated does not exclude the presence of other elements or other steps than those set out in a claim.

[0082] In the claims, any reference sign in parentheses cannot be interpreted as a limitation of the claim.

[0083] 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 the embodiments set out in the present description, but should be interpreted to include all equivalents which the claims are intended to cover by virtue of 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. Mixing device (40) of a gas in the solid state (2) in a liquid flow (6), the mixing device being intended to be connected to an inlet (22) of a circuit (12) on the one hand and to an outlet (21) of said circuit (12) on the other hand to form a closed circuit (12) in which the liquid flow (6) circulates in a loop, the mixing device comprising an introduction zone (50) extending along a first axis (X), the introduction zone (50) comprising: a. A first main inlet (52) intended to receive the liquid flow (6) tangentially to the first axis (X); b. A second inlet (53) intended to introduce the gas in the solid state (2) along an axis intersecting the first axis (X); c. An outlet (54) through which a mixture (33) composed of particles (32) of the gas in the solid state (2) and of the liquid flow (6) is intended to leave the introduction zone (50); the mixing device (40) further comprising a main outlet (55, 54, 65, 75) intended to be fluidically connected to the inlet (22) of the circuit (12) and through which the mixture (33) is intended to leave the mixing device (40), the particles (32) of the mixture being uniformly distributed in the liquid flow as it passes through the main outlet.

2. Mixing device according to claim 1, further comprising at least one second main inlet (52') intended to receive the second liquid flow (6) tangentially to the first axis (X), the main inlets (52, 52') being preferentially distributed along the introduction zone (50).

3. Mixing device according to claim 1 or 2, comprising a homogenization zone (60) arranged downstream of the introduction zone (50) and extending along the first axis (X), the homogenization zone (60) comprising: a. an inlet (64) fluidly connected to the outlet (54) of the introduction zone and intended to receive the mixture (33) from the introduction zone (50); b. a device (67) for homogenizing the particles (32) in the liquid flow (32) arranged downstream of the inlet (64) of the zone homogenization (60); c. an outlet (65) through which the mixture (33) having passed through the homogenization zone (60) is intended to leave the homogenization zone (60), the particles (32) of the mixture being detached from the inner wall of the homogenization zone upon passing the outlet (65) of the homogenization zone (60).

4. Mixing device according to claim 3, in which the homogenization device (67) comprises a deflector (61) arranged on a portion of the inner wall of the homogenization zone, the deflector (61) evolving parallel to the first axis (X) from a lower part (61a) towards an upper part (61b) while having an increasing thickness (e).

5. A mixing device according to claim 3 or 4, wherein the homogenizing device (67) comprises a static mixer (62) comprising a plurality of blades (62a, 62b) arranged in a staggered manner and on either side of the first axis (X), each of the plurality of blades having a curved portion (62c) forming a flow channel for the mixture (33), the blades being oriented so that two successive flow channels have a distinct orientation (X+, X-) around the first axis (X).

6. Mixing device according to any one of claims 3 to 5, wherein the homogenizing device (67) comprises a first diaphragm (63) configured to limit a first passage section of the mixture along the first axis (X).

7. Mixing device according to claim 6, wherein the homogenizing device (67) comprises a second diaphragm (66) downstream of the first diaphragm (63), configured to limit a second passage section of the mixture (33) along the first axis (X), at a distance from the first passage section.

8. Mixing device according to any one of claims 3 to 7, comprising a zone of parallelization (70) of current lines of the mixture arranged downstream of the homogenization zone (60) and extending along the first axis (X), the parallelization zone (70) comprising: a. an inlet (74) fluidically connected to the outlet (65) of the homogenization zone (60) and intended to receive the mixture (33) from the homogenization zone (60); b. a device (77) for parallelizing the flow lines of the mixture arranged downstream of the inlet (74) of the parallelization zone (70); c. an outlet (75, 55) through which the mixture (33) having passed through the homogenization zone (60) is intended to leave the parallelization zone (70), the particles (32) of the mixture being uniformly distributed in the liquid flow as it passes through the outlet (75, 55).

9. Mixing device according to claim 8, wherein the parallelization device (77) comprises at least one wall (71, 72) extending from the inlet (74) to the outlet (75) of the parallelization zone (70) parallel to the first axis (X).

10. Mixing device according to claim 8 or 9 in combination with claims 6 or 7, wherein the section of the parallelization zone evolves from the outlet section (64) of the homogenization zone (60) towards the outlet section (75) of the parallelization zone (70).

11. Method for mixing a gas in the solid state (2) in a liquid flow (6) of a closed circuit (12) in which the liquid flow (6) circulates in a loop, the method implementing a mixing device (40) according to any one of claims 1 to 10 and comprising the following steps: a. First step (110) of introducing at the first main inlet (52) the liquid flow (6) tangentially to the first axis (X), resulting in the creation of a swirling flow around the first axis (X) in the introduction zone (50); b. Second step (120) of introducing at the second inlet (53) the gas in the solid state (2), preferably in the form of longitudinal and continuous elements, along an axis intersecting the first axis (X); c. Third step (130) of destructuring the gas in the solid state (2) into particles (32) of gas in the solid state (2) so as to form a mixture (33) in which the particles (32) are distributed in the liquid flow (6).

12. Mixing method according to claim 11 using a mixing device according to any one of claims 3 to 7, further comprising a step (140) of detaching the particles (32) of the mixture (33) from the inner wall of the homogenization zone (60).

13. Mixing method according to claim 11 or 12 implementing a mixing device according to any one of claims 8 to 10, further comprising a step (150) of parallelizing the flow lines of the mixture (33) in the parallelization zone (70) so that the particles (32) of the mixture are uniformly distributed in the liquid flow (6).

14. A mixing method according to any one of claims 11 to 13, wherein the solid state gas (2) and the liquid stream (6) are carbon dioxide.

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