Solid-state gas melting device

Abstract

The present invention relates to an apparatus (8) for melting a gas (2) in a solid state, the apparatus comprising a closed loop (12) in which the same gas as the gas in the solid state (2) circulates in a liquid state (6) in the closed loop, the closed loop (12) comprising at least one inlet (14) for introducing the gas in the solid state (2) and an outlet (16) through which the gas in the liquid state (6) leaves the closed loop (12), the melting apparatus (8) comprising at least one heat exchanger (18) for exchanging heat between the gas in the liquid state (6) circulating in the closed loop (12) and another fluid.

Description

[Technical Field]

[0001] The present invention relates to the field of melting gases in the solid state, such as carbon dioxide. [Background technology]

[0002] A new supply chain is currently being developed for processing gases such as carbon dioxide, which involves a first step to capture the gas, a second step to transport it, and a final step to landfill the gas at a location very far from where it is captured.

[0003] This gas transport step is best performed when the carbon dioxide is in a solid state, especially for maritime transport, which is indeed the case at ambient pressure.

[0004] Therefore, in order to landfill this gas at a location very far from the capture site, it is necessary to use a means to change the state of the gas, converting it from a solid to a supercritical state, which is required by the constraints of geological sequestration.

[0005] Such phase changes of gases require an intermediate step, and the present invention aims to convert a solidified gas to a liquid state before converting the gas to a supercritical state for transport.

[0006] There are technical means to convert gases from a solid state to a liquid state. However, these means are not suitable for the above-mentioned supply chain, especially in the case of carbon dioxide. In fact, this supply chain contains a considerable amount of gas to be processed according to a continuous process, without carbon dioxide in a liquid state below 5.2 bar. Furthermore, the processing must comply with environmental constraints and consume as little energy as possible. The technical means of the art cannot solve these difficulties. Summary of the Invention [Problem to be solved by the invention]

[0007] The present invention at least partially overcomes the drawbacks of the state of the art by providing an apparatus for processing gases by phase change, comprising an apparatus for melting gases in the solid state, which can be carried out by the melting method according to the invention. [Means for solving the problem]

[0008] To that end, the present invention relates to a melting device for a gas in a solid state, comprising a closed loop, in which the same gas as the gas in a solid state circulates in a liquid state, the closed loop comprising at least one inlet for taking in the gas in a solid state and one outlet configured for a portion of the gas in a liquid state to leave the closed loop, the melting device comprising at least one heat exchanger designed to perform a heat exchange between the gas in a liquid state configured to circulate in the closed loop through the closed loop and another fluid, thereby heating the gas in a liquid state configured to circulate through the closed loop and melting the gas in a solid state in the closed loop, the outlet being positioned in the closed loop.

[0009] The melting device includes a closed loop configured to transform a gas in a solid state into a liquid state by melting.

[0010] The function of the heat exchanger is to heat the liquid gas circulating through the closed loop, thereby dissolving the solid gas continuously introduced into the closed loop, thus maintaining the proper temperature conditions so that the gas in the closed loop remains liquid.

[0011] According to an optional feature of the invention, the melting apparatus includes a solid-state gas decomposer that produces solid-state gas particles and that is in fluid communication with the closed-loop inlet, the decomposer being understood to be in fluid communication with the inlet either directly or through at least one other component.

[0012] The solid gas is pulverized by the decomposer, which makes it easier to incorporate into the liquid gas. Pulverizing the solid gas also reduces the melting time because the size of the solid gas flakes reduces the time the flakes remain solid.

[0013] The disintegrator may be, for example, a grinder into which a block of gas in solid state is poured, the grinder converting the block of gas in solid state into particles or flakes.

[0014] According to another feature, the closed loop comprises at least a first tributary and a third tributary, wherein at least the first tributary extends vertically, and the closed loop comprises a second tributary and a fourth tributary connecting the first tributary to the third tributary.

[0015] The branches may extend along a line. According to alternative embodiments, the branches may be coiled or may have angles. In fact, these branches are pipes assembled as closed loops.

[0016] The first branch is vertical, which improves heat transfer of the liquid gas stream toward the solid gas entering the closed loop through the closed loop inlet. By improving this transfer, the vertical configuration reduces the residence time of the solid gas while preventing the mixture from stratifying and freezing the liquid stream as the solid gas flows into the liquid gas circulating through the closed loop.

[0017] According to an optional feature, the solid gas cracker is located vertically above the fourth branch, such a layout making it possible to limit the penetration of liquid gas into the cracker.

[0018] According to another optional feature, the fourth branch comprises at least a first portion and a second portion, the first portion being located perpendicular to the inlet and having a flow cross-section of liquid gas strictly greater than that of the second portion. A mixture of solid and liquid gas flows through the first portion. When the solid gas comes into contact with the liquid gas flow, it dissolves into the liquid gas flow. To optimize dissolution and thus reduce the residence distance of the solid gas in the closed loop, the first portion has a larger volume than the second portion, thereby reducing the flow velocity of the liquid gas flow through the first portion compared to the flow velocity through the second portion. Reducing the flow velocity through the first portion allows the height of the first branch to be reduced.

[0019] According to another feature, the volume of the first tributary is strictly greater than the volume of the second tributary, the volume of the third tributary or the volume of the fourth tributary, so that the flow rate of the mixture of liquid gas and solid gas particles through the first tributary is lower than the flow rate of liquid gas through the second tributary, the third tributary or the fourth tributary.

[0020] The first branch of the closed loop collects both the liquid state gas flow and the solid state gas flow, which requires a larger volume compared to the volume of the other branches, and in the first branch, the solid state gas is already concentrated.

[0021] According to another optional feature, the heat exchanger is located in the third branch or in the second branch, or between the start of the fourth branch and the inlet of the closed loop, and the heat exchanger is located at a specific position in the closed loop where the liquid gas flow is free of solid gas particles.

[0022] The heat exchanger is configured to heat the gas in liquid state circulating through the closed loop and thus participates in the dissolution of the gas in solid state.

[0023] According to another optional feature, there is a circulation device for the flow of gas in the liquid state through the closed loop, said circulation device being located in the second branch or in the fourth branch, or between the start of the third branch and the heat exchanger, in the latter case the heat exchanger being located in the third branch.

[0024] The circulation device is configured to circulate the gas in a liquid state through a closed loop, which affects the time required for melting.

[0025] The greater the flow rate difference between the liquid and solid gases created by the circulation device, the higher the exchange rate and the faster the solid gas dissolves in the liquid gas.

[0026] A heat exchanger between the circulation device and the liquid gas outlet allows the liquid gas stream to be heated, thereby dissolving any potential residual particles of solid gas before a portion of the liquid gas is extracted through the closed loop outlet.

[0027] According to an embodiment, the circulation device is a pump configured to receive solid particles at its inlet.

[0028] According to an optional feature of the invention, the closed loop includes a mixing zone located between the outlet of the closed loop and the heat exchanger and before the inlet of the closed loop. Such a mixing zone improves uniformity in mixing the solid state gas into the liquid state gas stream. Such a mixing zone may include a static mixer or a dynamic mixer. An extrusion die for the solid state gas communicates with the mixing zone.

[0029] According to the characteristics of the melting device, the gas in the solid state and the gas in the liquid state are carbon dioxide. Therefore, these two states of gas are part of the melting device.

[0030] According to an option of the present invention, the melting device comprises a static or dynamic mixer integrated in a closed loop, which generates turbulence in the liquid gas stream, so that the solid gas particles are homogenized within said liquid gas stream.

[0031] The present invention also relates to an apparatus for processing gas by phase change, comprising: a melting device as described herein; at least one hopper configured to contain gas in a solid state; at least one pressurizing device for the gas in a solid state connected to an inlet of the closed loop; and at least one shut-off valve and at least one extrusion die located between the pressurizing device and the inlet of the closed loop; and the apparatus for processing gas by phase change comprises at least one high-pressure pump connected to an outlet of the closed loop and at least a first heat exchanger, wherein the high-pressure pump and the first heat exchanger are configured to increase the pressure and temperature of the gas in a liquid state, respectively, thereby changing the gas in the liquid state to a supercritical state.

[0032] A hopper is a tank that contains gas in solid form.

[0033] The apparatus for processing a gas by phase change includes an extrusion die configured to extrude a gas in a solid state as a longitudinally continuous element, and a flow rate of the gas in a liquid state through a closed loop causes the longitudinally continuous element to break down, thereby generating particles that are carried along a first branch of the closed loop.

[0034] For example, the pressurizing device is a rotor / stator set and at least one worm screw, and the function of the pressurizing device is to force the solid-state gas into an extrusion die, thereby changing the solid-state gas into a longitudinally continuous element. Furthermore, the pressurizing device increases the pressure of the solid-state gas to a value higher than the pressure of the liquid-state gas passing through the closed loop, thereby reducing the head loss of the components between the outlet of the pressurizing device and the inlet of the closed loop, particularly the extrusion die.

[0035] According to another optional feature, the processing device includes a thermodynamic circuit including at least one compression device, a first heat exchanger configured to convert the liquid gas from the high-pressure pump into a supercritical fluid, an expansion device, and a second heat exchanger functioning as an evaporator, wherein the first heat exchanger functions as a condenser in the thermodynamic circuit.

[0036] This first heat exchanger therefore heats the gas in liquid state from the closed loop, causing it to change state, which means changing to a supercritical state.

[0037] The present invention also relates to a method of melting a gas in a solid state implementing a melting device as described herein, the method comprising at least one step of circulating a gas in a liquid state through a closed loop, contacting the gas in a solid state entering the closed loop through an inlet with the gas in a liquid state circulating through the closed loop, increasing the temperature of the gas in a liquid state flowing through the closed loop, and releasing a portion of the gas in a liquid state through an outlet.

[0038] According to an optional embodiment, the melting method comprises melting gas in a solid state with gas in a liquid state in the first branch stream.

[0039] When the melting method includes a step of decomposing the gas in a solid state, the melting method includes a step of decomposing the gas in a solid state by a decomposition device.

[0040] The invention also relates to an apparatus for treating gases by phase change, which implements at least the melting method as described above, comprising at least one step of pressurizing the gas in the solid state before the decomposition step, and a step of changing the gas stream in the liquid state into a supercritical state after the step of compressing the gas in the liquid state.

[0041] The pressurizing step makes it possible to increase the pressure of the gas in solid state to a value higher than the pressure in the closed loop, so that the gas in solid state is transferred to the melting device according to the invention.

[0042] Other characteristics, details and advantages of the invention will become apparent from the following detailed description, given by way of non-limiting reference, with reference to the accompanying schematic drawings. [Brief explanation of the drawings]

[0043] [Figure 1] 1 shows an embodiment of a melting device according to the present invention; [Figure 2] 2 is a cross-sectional view of a solid state gas decomposition device included in the melting device of FIG. 1. [Figure 3] 3 is another cross-sectional view of the solid-state gas decomposition apparatus of FIG. 2. [Figure 4] 1 is a schematic diagram of a solid-state gas mixer included in a melter; FIG. [Figure 5] 2 is a schematic diagram of an apparatus for treating a gas by phase change, comprising the melting apparatus of FIG. 1, with a device for changing the liquid to a supercritical state; DETAILED DESCRIPTION OF THE INVENTION

[0044] The features, variations, and various embodiments of the invention described above or below in the detailed description may be associated in various combinations, provided they are not mutually contradictory or exclusive. Variations of the invention may also be envisioned that include only a selection of the features described below, apart from the other features described, provided that this selection of features is sufficient to confer technical advantage and / or to distinguish the invention from the state of the art.

[0045] The terms upstream and downstream are used herein to define the relative location of some components and should be interpreted relative to the direction of fluid flow through those components or associated circuits.

[0046] Figure 1 shows a melting device 8 according to the invention, designed to melt an initially solid gas 2. Such a melting device 8 comprises a closed loop 12 through which the same gas as the solid state gas 2 flows as a liquid, in other words as a gas stream 6 in the liquid state. Such a flow is indicated by a dotted line in Figure 1.

[0047] According to an embodiment of the present invention, the closed loop 12 comprises at least one inlet 14 for introducing the gas 2 in solid state. The inlet 14 is the region through which the gas 2 in solid state is fed into the closed loop 12.

[0048] The closed loop 12 also comprises an outlet 16 through which a portion of the flow of gas 6 in liquid state is discharged. In other words, the outlet 16 is where the flow of gas 6 in liquid state is extracted from the closed loop 12.

[0049] The melting device 8 operates continuously. Liquid gas 6 constantly flows through a closed loop 12. A predetermined volume of solid gas 2 is incorporated into the liquid gas 6 stream at a first point, i.e., an inlet 14, of the closed loop 12. A predetermined weight of liquid gas 6 substantially equal to the mass of the incorporated solid gas 2 is extracted from a second point, i.e., an outlet 16, of the closed loop 12. The volume of the extracted liquid gas 6 is determined as a function of the volumetric flow rate of the liquid gas stream 6 measured at the outlet 16 of the closed loop 12. The volume of the incorporated solid gas 2 is determined as a function of the liquid level of the liquid gas 6 measured in the expansion chamber 9. When the solid gas 2 and liquid gas 6 streams are carbon dioxide, the incorporated mass and the extracted mass represent between 1 / 11 and 1 / 12 of the weight of the liquid gas stream in the closed loop 12.

[0050] This keeps the volume of the mixture of liquid gas 6 and solid gas 2 constant in the closed loop, resulting in good mixture homogeneity and fast and powerful heat transfer from the liquid gas 6 to the solid gas 2. The flow rate ratio creates a large temperature difference between the solid gas 2 and the liquid gas stream 6, which results in good heat transfer and therefore faster melting. Furthermore, this good heat transfer makes it possible to prevent local freezing of the liquid gas stream 6 in contact with the solid gas 2 in the closed loop 12.

[0051] However, it is necessary to take into account start-up or shutdown phases of the melter 8 and temperature fluctuations of the mixture, which may cause volume differences within the closed loop 12. For this reason, an expansion chamber 9 is part of the closed loop 12. The expansion chamber 9 is located immediately upstream of the outlet 16 of the closed loop 12.

[0052] This expansion chamber 9 absorbs the change in volume of the liquid state gas 6 passing through the closed loop 12 during start-up or shut-down phases and temperature fluctuations of the mixture of liquid state gas and solid state gas, thereby balancing the mass difference between the solid state gas entering the closed loop 12 and the liquid state gas exiting the outlet 16 of the closed loop 12.

[0053] Thus, by adding a gas 2 in the solid state to a gas flow 6 in the liquid state, the melting device 8 according to the invention dissolves the gas in the solid state and generates a gas in the liquid state.

[0054] The melting device 8 according to the invention also comprises at least one heat exchanger 18 for exchanging heat between the gas 6 in liquid form arranged to circulate in a closed loop through the closed loop 12 and another fluid, for example glycol.

[0055] 1, the outlet 16 is advantageously located downstream of the heat exchanger 18. This location reduces the risk of gas in a solid state at the outlet 16. However, the outlet 16 may also be positioned upstream of the heat exchanger 18. Similarly, the outlet 16 may be positioned upstream of a circulation device 30 configured to move the liquid gas flow 6 through the closed loop 12. Such an alternative location of the outlet 16 is possible when dissolution of the gas in a solid state into a liquid state has previously occurred, which means being upstream of the closed loop.

[0056] The closed loop 12 comprises at least a first branch 20 and a third branch 24. The first branch 20 extends vertically or substantially vertically, which enhances melting of the gas from its solid state to its liquid state. Optionally, the third branch 24 is also substantially vertical.

[0057] The closed loop 12 also includes a second tributary 22 and a fourth tributary 26, which connect the first tributary 20 to the third tributary 24, thereby forming a loop that constitutes the closed loop 12.

[0058] Thus, first, second, third and fourth branches, labeled 20, 22, 24 and 26, are designed to conduct liquid state gas 6 from inlet 14 to outlet 16 of closed loop 12. First branch 20 has a volume strictly greater than the volumes of the other branches. First branch 20 takes in solid state gas 2 from inlet 14 of closed loop 12. This volume of first branch 20 allows the flow through this branch to be reduced compared to the flow rate of the other branches. This therefore increases the contact time between solid state gas particles 2 and liquid state gas 6.

[0059] On the other hand, the third branch 24 presents a smaller volume than the first branch 20 because, at this point in the closed loop 12, most of the gas 2 in solid state has already dissolved in the first branch 20 and the second branch 22, which allows the cross-section of the third branch 24 to be reduced compared to the cross-section of the first branch 20.

[0060] The expansion chamber 9 is a volume in which the volume of the liquid gas increases or decreases. The expansion chamber 9 is attached to the junction of the third branch 24 and the fourth branch 26, which is connected to the expansion chamber at a vertically lower position than the inlet where the third branch 24 is connected to the expansion chamber 9.

[0061] The third branch 24 comprises a heat exchanger 18 upstream of the expansion chamber 9. The function of the heat exchanger 18 is to heat the liquid gas stream 6, thereby dissolving the solid gas 2 mixed in the liquid gas stream 6, which circulates through the closed loop 12. At the same time, the outlet 16 is configured to extract a portion of the liquid gas 6 preheated by the heat exchanger 18.

[0062] Alternatively, the heat exchanger 18 is located in the second branch 22 or in the fourth branch 26 .

[0063] The heat exchanger 18 is located downstream of the circulation device 30 in the second branch 2 .

[0064] The circulation device 30 is configured to move the liquid state gas flow 6 through the closed loop 12. For example, such a circulation device 30 may be a pump. The greater the flow velocity difference between the liquid state gas 6 and the solid state gas 2 created by the circulation device 30, the greater the exchange rate and the faster the solid state gas 2 dissolves into the liquid state gas 6. In this case, the circulation device 30 is positioned between the end of the first branch 20 and the heat exchanger 18. The fourth branch 26 of the closed loop 12 comprises a first portion 36 and a second portion 38. The first portion 36 comprises a flow cross-section of the liquid state gas 6 that is strictly greater than the flow cross-section of the second portion 38.

[0065] The first section 36 is positioned vertically perpendicular to the inlet 14 of the closed loop 12, which is the flow path through which the dissolved solid gas 2 enters the closed loop 12 as particles 32. The cross-section of the first section 36 is larger than the cross-section of the second section 28, thereby reducing the flow velocity of the liquid gas 6 through the first section 36, where the particles 32 and the liquid gas 6 flow together, allowing the liquid gas 6 to coat the solid gas particles. The cross-section of the second section 28, which is smaller than the cross-section of the first section 36, saves some of the volume of the liquid gas 6 in the closed loop and reduces the material required to form the closed loop 12.

[0066] The melting device according to the present invention is configured so that the liquid gas 6 flows counterclockwise through the closed loop 12 from the second portion 38 to the first portion 36 .

[0067] The portion of the liquid state gas stream 6 that is not extracted from the closed loop 12 continues to circulate by the circulation device 30 along a substantially horizontal flow from the fourth branch 26 to the first branch 20, thereby maintaining the circulation of the liquid state gas stream 6 within the closed loop 12 and thus ensuring continuous operation of the device.

[0068] 2 and 3 show a decomposition device 34 for solid state gas 2. The decomposition device 34 is installed upstream of the inlet 14 of the closed loop 12 so that solid state gas particles flow into the liquid state gas stream. The decomposition device 34 for solid state gas 2 is configured to produce solid state gas 2 particles 32.

[0069] The melter 8 includes a mixing zone 40 of the solid gas 2 and the liquid gas stream 6, where particles 32 of the solid gas 2 previously decomposed by the decomposer 34 are carried away by the liquid gas stream 6 of the closed loop 12. The particles 32 of the solid gas 2 flow through the mixing zone 40 within the closed loop 12. As shown in FIG. 1 , the mixing zone 40 is part of the fourth branch 26. The mixing zone 40 is located between the outlet 16 of the closed loop 12 and the first branch 20. More specifically, the mixing zone 40 is located between the outlet 16 of the closed loop 12 and the first portion 36 of the fourth branch 26.

[0070] 2 and 3, the disintegrator 34 collects the solid gas 2 agglomerated as large blocks from a hopper 46. The blocks then pass through a reducer 47, which converts the blocks into particles that can flow to a pressurizer 50. For example, the reducer 47 can be a grinder.

[0071] The particles fall under the influence of gravity into a double stuffing screw 35 at the bottom of the feed cone, which supplies the solid state gas to a pressurizing device 50. By way of example, such a pressurizing device 50 is a double screw pump 37 which makes it possible to increase the pressure of the solid state gas 2 to a value at least equal to the pressure in the closed loop 12. The pressurizing device 50 thus increases the pressure of the solid state gas to a level at least equal to, for example, 30 bar.

[0072] There is also a shut-off valve 39, the function of which is to prevent liquid gas 6 from flowing back into the pressure pump 50. As particles of solid gas 2 flow through the shut-off valve 39, they are forced through an extrusion die 41, which causes the particles to form a plurality of longitudinally continuous elements.

[0073] As shown in FIG. 4, the longitudinally continuous elements are then cut by a liquid gas 6, which flows through the closed loop 12 and transforms the elements into particles 32. The particles 32 are mixed with the liquid gas stream 6 by a mixer 43, which generates turbulence in the liquid gas stream 6, thereby uniformly dispersing the particles 32 within the liquid gas stream 6. Such a mixer 43 may be, for example, a dynamic mixer or a static mixer. In the latter case, the mixer 43 may be a double impeller, as shown in FIG. 4. According to an alternative embodiment, a rotary feed valve is present, into which the solid gas 2 particles fall after being pulverized by a reducer 47. The rotary feed valve then feeds the double stuffing screw 35. The rotary feed valve is therefore positioned in the feed cone that directs the solid gas 2 particles to the double stuffing screw 35. The function of the rotary feed valve is to prevent clogging of the double stuffing screw 35 by periodically releasing a predetermined amount of particles of gas 2 in solid state.

[0074] 5 shows an apparatus 1 for treating a gas by phase change, which comprises at least the melting device 8 described above, in particular a device 34 for decomposing the gas, and a device 10 for converting the liquid to a supercritical state. The apparatus 1 for treating a gas by phase change may also comprise a hopper 46, a pressurizing device 50, a shut-off valve 39 and an extrusion die 41.

[0075] The device 1 for treating gas by phase change is designed to change a gas 2 in a solid state through a liquid state to a supercritical state 66, thereby storing the gas in a supercritical state, for example in an underground pocket.

[0076] As shown in FIG. 5, the apparatus 1 for treating a gas by phase change comprises the melting device 8 described above, at least a hopper 46, a decomposition device 34, a pressurizing device 50, a high-pressure pump 52, and a thermodynamic circuit 54 described below.

[0077] The hopper 46 is configured to receive the solid state gas 2, for example, from a conveyor belt (not shown). The hopper 46 is in communication with the decomposition device 34, whereby the solid state gas 2 received in the hopper 46 is brought to a pressurization device 50 for the same solid state gas 2.

[0078] The pressurizing device 50 is in fluid communication with the melting device 8, where the gas 2 in solid state is transformed into a liquid by melting, as described above.

[0079] The high pressure pump 52 is configured to increase the pressure of the liquid state gas stream 6 extracted from the closed loop 12 through the outlet 16 to approximately 100 bar, which causes the gas to reach a supercritical state 66 when the gas is carbon dioxide and the temperature of the gas is high.

[0080] 5 also shows a melting apparatus 8, which includes a circulation device 30, a heat exchanger 18, and an outlet 16 connected to each other by the loop configuration of the closed loop 12. A portion of the gas in liquid state that leaves the closed loop 12 through the outlet 16 thermally interacts with a thermodynamic circuit 54 as it flows through a first tube 56, shown in dotted lines in FIG.

[0081] Thermodynamic circuit 54 includes a first heat exchanger 58, as well as an expansion device 60, a compression device 62, and a second heat exchanger 64, all mounted in series to form thermodynamic circuit 54. Although not shown in this figure, a refrigerant, such as carbon dioxide or ammonia, flows along thermodynamic circuit 54. Thermodynamic circuit 54 is the portion of apparatus 10 that converts a liquid to a supercritical state.

[0082] The gas 6 in liquid state flows from the outlet 16 of the closed loop 12 along a first heat exchanger 58. This gas in liquid state is compressed to about 100 bar by the high-pressure pump 52 in a first pipe 56 and then flows to said first heat exchanger 58. At the same time, the refrigerant in the thermodynamic circuit 54 flows through the first heat exchanger 58.

[0083] The increase in temperature of the liquid state gas stream 6 across the first heat exchanger 58, relative to the pressure of the liquid state gas stream 6, causes a phase change, converting the initially liquid gas to a supercritical state 66. The first heat exchanger 58 serves as a condenser for the refrigerant passing through the thermodynamic circuit 54. The refrigerant also has a tendency to condense in thermal contact with the liquid state gas 6.

[0084] The refrigerant exiting the first heat exchanger 58 is directed to an expansion device 60, the function of which is to reduce the pressure of the refrigerant.

[0085] The refrigerant then continues to a second heat exchanger 64. The second heat exchanger 64 is located between the expansion device 60 and the compression device 62. The second heat exchanger 64 serves as an evaporator for the refrigerant passing through the thermodynamic circuit 54.

[0086] The refrigerant flows through a compression device 62 downstream of a second heat exchanger 64, which compresses the refrigerant and increases its pressure and therefore its temperature. At the end of the flow of the refrigerant through all components of the thermodynamic circuit 54, temperature and pressure parameters are collected, which allows the flow of gas, initially extracted as a liquid at outlet 16 and raised by high-pressure pump 52 to a pressure of about 100 bar, to reach a supercritical state 66.

[0087] A heat input circuit 68 is present in the second heat exchanger 64 to provide heat through the thermodynamic circuit 54 to vaporize the refrigerant. Seawater or glycol can flow through such a heat input circuit.

[0088] The fluid passing through the heat exchanger 18 is directed to a heat input section 80. Glycol can flow through this heat input section, thereby heating the liquid gas flow 6 passing through the closed loop 12 of the melting device 8 according to the present invention.

[0089] The present invention also relates to a melting method implementing the melting device 8 disclosed above. This melting method comprises a first step of circulating a gas stream 6 in a liquid state in a closed loop 12, in particular in four branches 20, 22, 24, 26 that define the closed loop 12. Such movement of the gas 6 in a liquid state is carried out, for example, by a circulation device 30 that is also located in the closed loop 12.

[0090] The melting method includes a second step of contacting the solid state gas 2, which accesses the closed loop 12 through the inlet 14, with the liquid state gas stream 6 circulating through the closed loop 12. This contact induces mixing and dissolution of the solid state gas 2, which has previously been reduced to particles 32 by the decomposer 34.

[0091] The melting method includes a third step of increasing the temperature of the liquid gas stream 6 circulating through the closed loop 12. The increase in temperature of the liquid gas stream 6 is performed by the heat exchanger 18 of the closed loop 12, which promotes the dissolution of the solid gas 2 particles 32, thereby best removing any solid gas 2 particles from the decomposition device 34.

[0092] Finally, the melting method includes a fourth step of releasing a portion of the gas stream 6 in a liquid state circulating in the closed loop 12 through the outlet 16. This portion of the gas stream 6 in a liquid state extracted from the closed loop 12 is compressed to about 100 bar and then directed to a thermodynamic circuit 54 configured to convert said gas stream 6 in a liquid state to a supercritical state, thereby producing a gas 66 in a supercritical state for storage, for example, in an underground pocket.

[0093] The present invention also relates to a method for treating a gas by phase change, which method comprises the above-mentioned steps of the melting method, and in addition comprises a first step of pressurizing the gas 2 in solid state, for example before the step of decomposing the gas in solid state.

[0094] The solid gas 2 in the hopper 46 needs to be reduced to particles 32 so that the solid gas 2 is more easily dissolved in the liquid gas 6 flowing through the closed loop 12. This is the function of the decomposer 34, as will be described below.

[0095] The method for treating gas by phase change also includes, after the step of extracting the gas stream 6 in a liquid state during the melting method, a second step of converting said liquid gas stream 6 to a supercritical state, whereby the gas is injected in a supercritical state into the underground pocket.

[0096] In the above description, the gas in the solid state 2 and the gas stream in the liquid state 6 are the same gas. The gas is preferably carbon dioxide. The means and configuration of the melting device 8 and the device 1 for processing a gas by phase change are particularly suitable for this gas.

[0097] The present invention achieves the goal of providing an optimized solution for industrial-scale dissolution of large amounts of gas stored in solid state, followed by conversion of the gas to a supercritical state and injection into landfills, as described above. Such a solution can be applied to carbon dioxide, thereby reducing greenhouse gas emissions.

[0098] The present invention is not limited to the means and arrangements described and illustrated herein, but also includes all equivalent means and arrangements and all technically valid combinations of these means.

Claims

1. 1. A melting device (8) for a gas in a solid state (2), comprising a closed loop (12) designed to circulate the same gas in a liquid state (6) through the closed loop (12) in the closed loop, the closed loop (12) comprising at least one inlet (14) for taking in the gas in a solid state (2) and one outlet (16) configured to allow a portion of the gas in a liquid state (6) to exit the closed loop (12), the melting device (8) comprising at least one heat exchanger (18) designed to exchange heat between the gas in a liquid state (6) configured to circulate in a closed loop through the closed loop (12) and another fluid, thereby heating the gas in a liquid state configured to circulate through the closed loop and melting the gas in the solid state in the closed loop, the outlet (16) being positioned in the closed loop (12).

2. The melting apparatus (8) of claim 1, further comprising a decomposition device (34) for the solid state gas (2) that produces particles (32) of the solid state gas (2) and that is in communication with the inlet (14) of the closed loop (12).

3. 3. The melting device (8) of claim 1 or 2, wherein the closed loop (12) comprises at least a first tributary (20) and a third tributary (24), at least the first tributary (20) extending vertically, and the closed loop (12) comprises a second tributary (22) and a fourth tributary (26) connecting the first tributary (20) to the third tributary (24).

4. 4. The melting device (8) according to claim 3, wherein the decomposition device (34) of the solid state gas (2) is located vertically above the fourth branch (26).

5. 5. The melting device (8) according to claim 3 or 4, wherein the fourth branch (26) comprises at least a first portion (36) and a second portion (38), the first portion (36) being located perpendicular to the inlet (14), and the first portion (36) comprising a flow cross-section of the gas flow (6) in the liquid state that is strictly greater than the flow cross-section of the second portion (34).

6. 6. The melting device (8) according to claim 3, wherein the volume of the first branch (20) is strictly greater than the volume of the second branch (22), the volume of the third branch (24) or the volume of the fourth branch (26).

7. 7. The melting device (8) according to claim 3, wherein the heat exchanger (18) is located in the third branch (24) or the second branch (22), or between the start of the fourth branch (26) and the inlet (14) of the closed loop (12).

8. 8. The melting device (8) according to claim 3, further comprising a circulation device (30) for the liquid state gas flow (6) passing through the closed loop (12), the circulation device (30) being located in the second branch (22) or in the fourth branch (26), or between the start of the third branch (24) and the heat exchanger (18).

9. 9. The melting device (8) of claim 1, wherein the closed loop (12) comprises a mixing zone (40) located between the outlet (16) of the closed loop (12) and the heat exchanger (18) and before the inlet (14) of the closed loop (12).

10. The melting device (8) according to any one of claims 1 to 9, wherein the gas in the solid state (2) and the gas in the liquid state (32) are carbon dioxide.

11. An apparatus (1) for processing a gas by phase change, comprising a melting device (8) according to any one of claims 1 to 10, at least one hopper (46) configured to receive the gas (2) in a solid state, at least one pressurizing device (50) for the gas (2) in a solid state connected to the inlet (14) of the closed loop (12), at least one shut-off valve (39) and at least one extrusion duct located between the pressurizing device (50) and the inlet (14) of the closed loop (12). and (41), wherein the apparatus (1) for treating gas by phase change comprises at least one high-pressure pump (52) connected to the outlet (16) of the closed loop (12) and at least a first heat exchanger (58), wherein the high-pressure pump (52) and the first heat exchanger (58) are configured to increase the pressure and temperature of the gas in a liquid state (6), respectively, thereby changing the gas in a liquid state (6) to a supercritical state.

12. 12. The apparatus (1) for processing gas by phase change according to claim 11, comprising a thermodynamic circuit (54) including at least one compressor (62), the first heat exchanger (58) configured to change the gas (6) in a liquid state from the high-pressure pump (52) to a supercritical state, an expansion device (60), and a second heat exchanger (64) functioning as an evaporator.

13. 11. A method for melting a gas (2) in a solid state by implementing a melting device (8) according to any one of claims 1 to 10, comprising: - circulating said gas in liquid state (6) through said closed loop (12); - contacting said gas in solid state (2) accessing said closed loop (12) through said inlet (14) with gas in liquid state (6) circulating through said closed loop (12); - increasing the temperature of the gas in liquid state (6) circulating through the closed loop (12); - removing a portion of said gas in liquid state (6) through said outlet (16); A method for dissolving, comprising at least the steps of:

14. The melting method according to claim 13, wherein the gas in the solid state (2) and the gas in the liquid state (32) are carbon dioxide.

15. 15. The melting method according to claim 13 or 14, when dependent on claim 2, including the step of decomposing the gas (2) in solid state by means of the decomposition device (34).

16. A method (1) for processing gases by phase change, at least by carrying out the melting method according to claim 15, which additionally comprises: - pressurizing said gas in solid state (2) before said decomposition step; - after the step of compressing the gas in the liquid state (6), converting the gas stream (6) in the liquid state to a supercritical state (66); 1. A method (1) for treating a gas by phase change, comprising at least:

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