Connection device for a plant for treating products by high-temperature thermal treatment

Abstract

The present invention relates to a connection device (16) intended to connect a container (12) for treating waste by high-temperature heat treatment and / or by vitrification with at least one source (18) of a product containing said waste and intended to be treated in the container (12) and to connect it with a gas extraction device (20), the connection device (16) having a bottom end (42) intended to be connected to the container (12) and a gas extraction device (20) connected to said at least one source (18). The connecting device (16) comprises a cylindrical body (38) having a top end (40) intended to be connected to a gas extraction device (20) and an intermediate opening (48) intended to be connected to a gas extraction device (20), the connecting device (16) comprising a connecting element (54) made of a gas-permeable element extending coaxially with the cylindrical body (38), the connecting element (54) comprising a top end (56) disposed at the top end (40) of the cylindrical body (38), and the connecting element (54) comprising a bottom section (62) extending vertically below the bottom end (42) of the cylindrical body (38).

Description

[Technical Field]

[0001] The present invention relates to a connection device for a plant for treating a product to be treated, such as a waste, a reactant or any other input, by high-temperature heat treatment and / or by vitrification, as well as to a treatment plant comprising this connection device.

[0002] The invention more particularly relates to a connection device intended to allow an effective separation between the product stream to be treated and the gas stream generated during the treatment process.

[0003] The present invention is in the field of treating mixed hazardous waste with a view to storing it for long periods in suitable containers. [Background technology]

[0004] In the context of the operation and / or decommissioning of nuclear facilities or other plants containing toxic or contaminated elements, it has proven essential to treat the waste resulting therefrom, whether consisting of metallic waste, e.g. stainless steel, copper and / or aluminium, and / or organic waste, e.g. polyvinyl chloride (PVC) and polyethylene terephthalate (PET), or even mineral waste, e.g. glass fibre. All these materials may be contaminated with radioactive elements, and in particular fissile materials.

[0005] Generally, this waste must be treated and processed to minimize its volume, depending on its radioactivity, so as to allow for its long-term storage and preservation.

[0006] One method for treating this contaminated waste involves high-temperature vitrification with container consumption. This method is commonly referred to as "In-Can Vitrification" or ICV.

[0007] The product may also be treated by high temperature thermal treatment, in which case there is no vitrification, but the waste is mixed with other inputs that do not necessarily react with the waste to form a package of treated waste at the end of the process.

[0008] Generally, therefore, the products to be treated consist of waste, reactants in the case of vitrification operations, and inputs which may or may not react with the waste but which participate in the treatment of the waste.

[0009] FIG. 1 shows an example of one embodiment of a plant 10 for implementing such a method.

[0010] The plant 10 comprises a container 12 in which the product to be treated is intended to be treated.

[0011] When this method is carried out, the container 12 is placed in the furnace 14 and gradually fed with the waste to be treated.

[0012] At the end of the method, the filled container 12 is cooled and then extracted to form a waste package, which may or may not be vitrified.

[0013] The container 12 is supplied with the product to be treated by a connection device 16 which is connected to a source 18 of the product to be treated, to an extraction device 20 capable of extracting gases produced during the treatment process, and to the container 12. This connection device 16 is further arranged through the wall of the furnace 14.

[0014] When this process is carried out, the product introduced is initially at ambient temperature, while the container 12 is at a very high temperature. The product is then heated significantly, which causes the release of vapors and gases that arise from the chemical reaction within the vessel.

[0015] This release may be associated with melting of material within the container 12 .

[0016] In the connection device 16, the products move vertically downward, while the gases and vapors move upward.

[0017] These two flows oppose each other, compromising the filling efficiency of the container 12. In addition, the upward flow of gas can entrain some of the product, which is then directed towards the extractor 20 rather than towards the container 12.

[0018] In addition, when they are introduced, the products undergo chemical and physical changes within the connection device 16. These products may then adhere to the walls of the connection device 16 and gradually clog it. In addition, products that agglomerate on the walls of the connection device may prevent its subsequent use. Summary of the Invention [Problem to be solved by the invention]

[0019] The object of the invention is to propose a connection device which makes the introduction of products in a treatment method more reliable. [Means for solving the problem]

[0020] The invention proposes a connection device intended to connect a container for treating waste by high-temperature heat treatment and / or by vitrification with at least one source of the products intended to be treated in the container and with a gas extraction device, The connecting device comprises a cylindrical body having a bottom end intended to be connected to a container, a top end intended to be connected to the at least one product source, and an intermediate opening intended to be connected to a gas extraction device, the connecting device comprising a connecting element made of a gas-permeable element extending coaxially with the cylindrical body, the connecting element comprising a top end located at the top end of the cylindrical body, and a bottom section extending vertically below the bottom end of the cylindrical body.

[0021] The connecting elements of the connecting device make it possible to separate the conduits and separate the waste stream and the gas stream, which therefore do not interfere with each other.

[0022] In addition, the waste does not come into contact with the walls of the connection device, preventing clogging thereof.

[0023] Preferably, the diameter of the connecting element is less than the inner diameter of the cylinder.

[0024] Preferably, the connecting element is mounted so that it can rotate about a common main axis A of the cylinder and the connecting element.

[0025] Preferably, the top end of the connecting element is connected to a means for rotationally guiding the connecting element relative to the cylinder and relative to the means for rotating the connecting element.

[0026] Preferably, the connecting element is made of a flexible material and the cylinder includes at least one obstacle that protrudes radially inward relative to the inner wall of the cylinder and causes deformation of the connecting element when it rotates within the cylinder.

[0027] Preferably, the bottom section includes at least one mass attached thereto.

[0028] Preferably, the mass is made from the same material as the connecting element.

[0029] Preferably, the mass is in the form of a ring coaxial with the connecting element.

[0030] Preferably, the bottom section comprises a plurality of vertically dispersed masses.

[0031] Preferably, the connecting element is an element that is impermeable to the waste material and permeable to the gas that is to be extracted by the extractor.

[0032] Preferably, the connecting element is made from woven glass fibre fabric.

[0033] Preferably, the top end of the connecting element is removably connected to the cylinder.

[0034] The present invention also relates to a plant for treating waste by high-temperature thermal treatment, comprising a container placed in a high-temperature furnace, at least one source of waste to be treated, a device for extracting gases generated during operation of the plant, and a connecting device according to the invention, which includes a connecting element, characterized in that the bottom section of the connecting element extends inside the container.

[0035] Preferably, all products to be processed in the container form one substance, and the bottom section of the connecting element extends to the surface of that substance inside the container. [Brief explanation of the drawings]

[0036] [Figure 1] 1 is a schematic diagram of a plant for treating contaminated waste, including a connection device according to the present invention; [Figure 2] 2 is an enlarged schematic view of a portion of the plant shown in FIG. 1, showing the connections between the connecting device, the vessel, and the furnace. [Figure 3] 1 is an enlarged view of a connection device according to the present invention; DETAILED DESCRIPTION OF THE INVENTION

[0037] In the following description, references to vertical orientation will be understood to be relative to the Earth's gravity.

[0038] As previously mentioned, FIG. 1 shows a plant 10 for carrying out a method for treating contaminated products by high temperature vitrification.

[0039] The plant includes a container 12 , a furnace 14 , a connection device 16 that connects the container 12 to a source 18 of the product to be treated, and to an extraction device 20 .

[0040] As previously mentioned, the products used in the plant 10 consist of the waste to be treated, strictly speaking, reactants which react with the waste in the case of a vitrification operation, and inputs which do not necessarily react with the waste but which participate in the treatment of the waste.

[0041] The product may be in liquid form, in which case it is stored in a tank 22 and conveyed by a pump 24 through the connecting device 16 to the container 12 .

[0042] The product may be in solid, powder or viscous form and is therefore stored in vessel 26. The product is then conveyed by gravity through connecting device 16 to container 12.

[0043] An airlock system including two valves 28 makes it possible to isolate the interior of the vessel 26, which is in contact with the ambient air, from the rest of the interior of the plant 10, in which the gas to be treated is present.

[0044] The airlock system allows the product to be gradually introduced into the plant without risking venting gases to the outside or introducing air into the plant.

[0045] The extraction device 20 comprises an extractor 30 which draws in the gases produced during the treatment method and discharges them in the direction of suitable retreatment and / or storage means. It will be understood that other components for treating the gases can be arranged in the extraction device 20, upstream or downstream of the extractor, without departing from the technical field of the present invention.

[0046] The extractor 20 also includes a dust remover 32 , a scrubber / condenser 34 and an ultra-high density filter 36 , all located upstream of the extractor 30 .

[0047] The dust collector 32 settles out any dust present in the gas stream which is removed by countercurrent circulation of a liquid elevated to its boiling point.

[0048] The scrubber / condenser 34 performs cooling of the gas coming from the culverter 32 and additional scrubbing by countercurrent circulation of an acidic or complexing solution.

[0049] The filter 36 provides a final barrier to fine products and particles before they reach the extractor 30 .

[0050] As seen in more detail in FIG. 2, the connection device 16 that connects the container 12 to the product source 18 and to the extraction device 20 includes a cylindrical body 38 that includes a major axis A that is oriented vertically in the direction of the Earth's gravity.

[0051] The cylinder 38 includes a top end 40 that is connected to the product source 18 and a bottom end 42 that is connected to the container 12 .

[0052] The bottom end 42 is therefore positioned inside the furnace 14 and includes an opening 44 through which the cylinder 38 passes.

[0053] Additionally, the bottom end 42 of the cylinder 38 is in contact with the container 12 in the furnace 14 , which is raised to a high temperature substantially equal to that of the container 12 .

[0054] To limit heating at the top of the connection device 16, the cylinder 38 includes a double jacket 46 disposed on the outside of the furnace 14, the purpose of which is to limit the upward propagation of heat.

[0055] By way of non-limiting example, the double jacket 46 includes conduits (not shown) for circulating a heat transfer fluid, such as chilled or temperature-conditioned water or pressurized air.

[0056] The cylinder 38 includes an opening 48 at its top and an outer sleeve 50 that connects the interior volume of the connection device to the extractor 20 .

[0057] When the product processing method is carried out, the product flows vertically downward through the cylinder under the influence of the Earth's gravity.

[0058] Upon entering container 12, at least some of the product melts. Material 52 gradually accumulates inside container 12, eventually filling it. In the following description, the term material 52 is used to refer to all products present inside container 12, whether or not they are molten, that are elevated to high temperatures for processing.

[0059] When they are raised to high temperatures and / or when they come into contact with molten material, the products produce gases that flow vertically upward through the cylinder 38, i.e., in the opposite direction to the product being fed into the container 12.

[0060] To separate the gas stream from the product stream, the connecting device 16 includes a connecting element 54 disposed on the cylindrical body 38 .

[0061] The connecting element 54 defines a conduit that extends within the cylinder 38 from the top end 40 of the cylinder 38 to the interior of the container 12 .

[0062] According to one preferred but non-limiting embodiment, the connecting element 54 consists of a tubular element extending coaxially with the cylinder 38, i.e. vertically.

[0063] It includes a top end 56 disposed at the top end 40 of the cylinder 38 and a bottom end 58 in contact with the substance 52 .

[0064] Thus, the connecting element 54 includes a top section 60 disposed on the cylindrical body 38 of the connecting device 16 and a bottom section 62 extending vertically below the bottom end 42 of the cylindrical body 38 .

[0065] The free end of the bottom section 62 is in contact with the substance 52 and mixes with it as the level of the substance 52 in the container 12 rises.

[0066] Preferably, the connecting element 54 is made of a material that can be preserved in the material to be treated. The connecting element 54 is then "lost." According to one variant, only the bottom section 62 of the connecting element 54 is lost and thus detached from the rest of the connecting element 54.

[0067] The physical and chemical reactions that produce the gas occur both inside and outside of the connecting element 54 .

[0068] Therefore, to allow the evacuation of gas and its flow in the direction of the extractor 20, the connecting element 54 is designed to be permeable to gas but impermeable to the product poured into the container 12.

[0069] The dimension of the connecting element 54 is less than the inner diameter of the cylinder 38 .

[0070] The connecting element 54 therefore extends radially at a distance from the inner wall 74 of the cylindrical body 38 and thus delimits a peripheral conduit through which the gas intended to be extracted can flow.

[0071] According to a preferred embodiment, the connecting element 54 is made of woven glass fiber, which therefore melts with the rest of the molten material, but does not melt at the ambient temperature in the furnace and in the container. Preferably, this material is silica-based.

[0072] The dimensional characteristics of the connecting element 54 are defined to allow for the transport of product from the top end 40 of the cylinder 38 to the bath of substance 52 .

[0073] The mesh size of the fabric must form a barrier to any type of product being conveyed through the connecting element 54 while allowing the escape of gases to the extractor 20 .

[0074] According to one variant embodiment, the connecting element 54 consists of a metal tube, for example made of stainless steel or aluminum, which includes an orifice intended to allow the gas to escape to the extractor 20 .

[0075] According to one non-limiting example embodiment, the connecting element 54 is 2.5 meters long and has a diameter of 20 centimeters.

[0076] As the products flow through the connecting element 54, it is possible that they may solidify there and clog it.

[0077] To prevent this clogging and thus promote product flow in the connecting element 54, the connecting element 54 is a flexible element and the connecting device 16 includes means for periodically deforming the connecting element 54. This embodiment is advantageous when the connecting element 54 is made from woven glass fabric, as previously mentioned.

[0078] According to another embodiment of the connection device, shown in FIG. 3, the connection device 54 is mounted so that it can rotate about a main axis A within the cylindrical body 38 .

[0079] For this purpose, the top end 56 of the connecting element 54 is connected to a rotary support 64 which is supported for rotation by the cylinder 38. This rotary support 64 allows the product to be treated to pass through it.

[0080] The rotary support 64 includes a cylindrical barrel 66 to which the top end 56 of the connecting element 54 is secured, and a top radial collar 68 that provides a rotational connection between the cylindrical body 38 and the rotary support.

[0081] The cylindrical body 38 comprises an annular base 70 extending in a plane perpendicular to the main axis A, which supports the rotary support 64 by means of its radial collar 68 , here in particular by means of a ball bearing 72 .

[0082] The rotary support 64 is further connected to a means (not shown) for driving it in rotation.

[0083] In addition to its rotation about the main vertical axis A, the connecting element 54 also deforms radially to prevent jamming of the connecting element 54 .

[0084] The inner wall 74 of the cylinder is for this purpose made here from the same metal as the cylinder 38 and includes an obstacle 76 which projects radially in the direction of the connecting element 54 .

[0085] The radial height of each obstacle 76 is greater than the radial distance between the connecting element 54 and the inner wall 74 of the cylindrical body 38 so as to cause radial deformation of the connecting element 54 .

[0086] The obstacles 76 are distributed vertically and circumferentially on the inner wall 74 of the cylinder 38 so as not to impair the possibility of product flow.

[0087] The bottom end 58 of the connecting element 54 is in permanent contact with the material 52, which may prevent the connecting element 54 from maintaining its cylindrical shape during rotation.

[0088] For this purpose, masses 78 are placed in the bottom section 62 of the connecting element 54. These masses 78 are preferably annular and attached to the outside of the connecting element 54 so as not to impede the flow of the product.

[0089] Masses 78 are preferably made from the same material as connecting elements 54 so as to melt in the final processing material and optionally in material 52. It will be understood that alternative embodiments in which all masses 78 or some of them are made from a material other than that of connecting elements 54 can also form part of the present invention.

[0090] The presence of lumps 78 in part of the bottom section 62 of the connecting element 54, and optionally in the molten material, makes it possible to generate agitation of the material 52 in combination with the rotational movement of the connecting element 54. This feature is used to improve the homogenization conditions, which is also important for methods that use thermal convection in the molten medium to provide this mixing.

[0091] According to another embodiment of the connecting element 54, whether or not it can rotate about the main axis A, its top end 56 is removably connected to the top end 40 of the cylindrical body 38.

[0092] This allows the connection element 54 to be removed at the end of the filling sequence of the processing method and dropped into the container 12. The connection element 54 may then be incorporated into the substance 52 and melted, or not.

[0093] The method for processing a product using the plant 10 just described therefore comprises successive steps.

[0094] First, the container 12 , optionally loaded with product, is placed in the furnace 14 and then connected to the connection device 16 .

[0095] Next, the connecting element 54 is fitted into the connecting device 16 from the top end 40 of the barrel 38 .

[0096] The furnace 14 is then heated, the extractor is started, and, if applicable, the connecting element 54 is set to rotate.

[0097] The container 12 is then supplied with the product to be processed by a connection device 16 .

[0098] The product is then heated and degassed, and the gas produced is discharged to the extractor 20 through the connecting element 54. Upon arriving at the surface of the material 52, the supplied and heated product is incorporated into the accumulation of this material 52.

[0099] When the container 12 is filled, the connecting element 54 and, if applicable, the mass 78 come into contact with the substance.

[0100] Once all of the product to be processed has been loaded into the container 12 , the rotation of the connecting element 54 is stopped and the connecting element 54 is then removed from the top end 40 of the cylinder 38 so that it can be loaded into the substance 52 .

[0101] The connecting element 54 to which the product may remain stuck is not used in the next implementation of the treatment method but is renewed, which makes it possible to ensure the reproducibility of the method without variations in implementation conditions.

[0102] In a method for treating material resulting from the cleanup / dismantling of a nuclear facility at the end of its operation, the properties of which are neither completely known nor uniform throughout the body to be treated, the use of connecting element 54 extending from top end 40 of cylinder 38 to material 52 makes it possible to maintain the cleanliness of the process equipment, which is not or only little contaminated by radioactive contaminants present in powder and particulate form. Renewing connecting element 54 further makes it possible to ensure the radiological cleanliness of plant 10. [Explanation of symbols]

[0103] 10 Plant 12 containers 14 Furnace 16 Connecting Devices 18 Source 20 Extraction device 22 Tank 24 Pump 26 Container 28 valves 30 extractor 32 Dust remover 34 Cleaner / Condenser 36 filters 38 Cylinder 40 Apex 42 Bottom end 44 Aperture 46 Double Jacket 48 Aperture 50 outer sleeve 52 Substance 54 Connecting Elements 56 Apex 58 Bottom end 60 Top Section 62 Bottom Section 64 Rotating support 66 Cylindrical Barrel 68 Radial Collar 70 Circular Base 72 ball bearings 74 Inner wall 76 Obstacles 78 lump

Claims

1. A connection device (16) intended to connect a container (12) for treating waste by high-temperature heat treatment and / or by vitrification with at least one source (18) of a product containing said waste and intended to be treated in said container (12), and with a gas extraction device (20), comprising: A connection device (16) comprising a cylindrical body (38) having a bottom end (42) intended to be connected to said container (12), a top end (40) intended to be connected to said at least one product source (18), and an intermediate opening (48) intended to be connected to said gas extraction device (20), The connection device (16) includes a connection element (54) made of a gas-permeable element extending coaxially with the cylindrical body (38), the connection element (54) including a top end (56) disposed at the top end (40) of the cylindrical body (38), and the connection element (54) including a bottom section (62) extending vertically below the bottom end (42) of the cylindrical body (38).

2. 2. The connecting device (16) of claim 1, wherein the diameter of the connecting element (54) is less than the inner diameter of the cylindrical body (38).

3. 3. The connecting device (16) according to claim 1 or 2, characterized in that the connecting element (54) is mounted so as to be able to rotate about a common main axis (A) of the cylindrical body (38) and the connecting element (54).

4. 4. The connecting device (16) of claim 3, wherein the top end (56) of the connecting element (54) is connected to a means (64) for rotationally guiding the connecting element (54) relative to the cylindrical body (38) and relative to a means for rotating the connecting element (54).

5. 5. The connection device (16) according to claim 3 or 4, characterized in that the connection element (54) is made of a flexible material and the cylindrical body (38) includes at least one obstacle (76) that protrudes radially inward relative to an inner wall (74) of the cylindrical body (38) and causes deformation of the connection element (54) when it rotates within the cylindrical body (38).

6. 6. A connection device (16) according to any one of claims 1 to 5, characterized in that the bottom section (62) includes at least one mass (78) attached thereto.

7. 7. A connecting device (16) according to claim 6, characterized in that said mass (78) is made from the same material as said connecting element (54).

8. 8. A connecting device (16) according to claim 7, characterized in that said mass (78) is in the form of a ring coaxial with said connecting element (54).

9. 9. A connection device (16) according to any one of claims 6 to 8, characterized in that the bottom section (62) comprises a plurality of vertically distributed masses (78).

10. 10. The connection device (16) according to any one of claims 1 to 9, characterized in that the connection element (54) is an element impermeable to the waste and permeable to the gas to be extracted by the extraction device (20).

11. 11. The connecting device (16) according to claim 10, characterized in that the connecting element (54) is made of woven glass fabric.

12. 12. The connecting device (16) of any one of claims 1 to 11, characterized in that the top end (56) of the connecting element (54) is removably connected to the cylindrical body (38).

13. A plant (10) for treating waste by high-temperature thermal treatment, comprising: a container (12) placed in a high temperature furnace (14); at least one source (18) of waste to be treated; a device (20) for extracting gases generated during the operation of the plant (10); A connection device (16) according to any one of claims 1 to 12, comprising a connection element (54); Including, A plant (10) characterized in that the bottom section (62) of the connecting element (54) extends inside the container (12).

14. 14. The plant (10) according to claim 13, characterized in that all products to be processed in the container (12) form one substance (52), and the bottom section (62) of the connecting element (54) extends inside the container (12) to the surface of the substance (52).

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