SYSTEM FOR HIGH-TEMPERATURE TIGHT COUPLING OF A STACK HAVING SOEC/SOFC-TYPE SOLID OXIDES

Abstract

A coupling system for high-temperature tight coupling of a stack having SOEC/SOFC-type solid oxides is described. The system includes a threaded hollow connector, a smooth hollow connector, and a threaded nut. The threaded hollow connector includes an opening for establishing fluid communication with a gas inlet/outlet pipe and is intended to be attached to the gas inlet/outlet pipe. The smooth hollow connector includes an opening for establishing fluid communication with a gas inlet/outlet pipe of the stack and is intended to be attached to the inlet/outlet pipe. The threaded nut engages with the threaded hollow connector to form a screw/nut system, slides relative to the smooth hollow connector, and includes a first threaded portion and a second smooth portion in sliding contact with the smooth hollow connector.

Claims

1-15. (canceled)

16. An assembly, comprising: a stack having SOEC/SOFC-type solid oxides operating at a high temperature; and a system coupling the stack to a furnace, the system comprising: a threaded hollow connector, which is at least partially threaded on an outer surface thereof, is intended to be attached to a gas inlet/outlet pipe, and comprises an opening for establishing fluid communication with the gas inlet/outlet pipe, a smooth hollow connector, which has an outer surface that is at least partially smooth, is intended to be attached to a gas inlet/outlet pipe of the stack, and comprises an opening for establishing fluid communication with the gas inlet/outlet pipe of the stack, and a threaded nut, which engages with the threaded hollow connector to form a screw/nut system, slides relative to the smooth hollow connector, and comprises a first threaded portion on an inner surface and a second smooth portion on an outer surface, wherein the smooth hollow connector and the threaded hollow connector each comprise an opening for establishing fluid communication with one another, the first threaded portion of the threaded nut engages with the thread of the threaded hollow connector, and the second smooth portion of the threaded nut is in sliding contact with the smooth hollow connector.

17. The assembly according to claim 16, wherein the smooth hollow connector comprises a rim that protrudes relative to the smooth outer surface thereof, the threaded nut comprises a rim that protrudes relative to the first threaded portion thereof, and the rim of the smooth hollow connector and the rim of the threaded nut contacts one another and stops the sliding of the threaded nut relative to the smooth hollow connector.

18. The assembly according to claim 17, wherein the system further comprises a gasket placed between the rim of the smooth hollow connector and the rim of the threaded nut.

19. The assembly according to claim 16, wherein the smooth hollow connector, the threaded nut and the threaded hollow connector are made from a nickel-based superalloy and/or austenitic stainless steel.

20. The assembly according to claim 16, wherein the smooth hollow connector comprises a bore for attaching it to the gas inlet/outlet pipe of the stack, and the threaded hollow connector comprises a bore for attaching it to the gas inlet/outlet pipe.

21. The assembly according to claim 16, wherein the system further comprises a gasket placed between the threaded hollow connector and the smooth hollow connector.

22. The assembly according to claim 16, wherein a nominal diameter of the threaded nut lies in the range of from M20 to M30.

23. The assembly according to claim 16, wherein the threaded hollow connector has a height that lies in the range of from 15 to 30 mm and a diameter that lies in the range of from 20 to 30 mm.

24. The assembly according to claim 16, wherein the smooth hollow connector has a height that lies in the range of from 45 to 70 mm and a maximum diameter of 30 mm.

25. The assembly according to claim 16, wherein the first threaded portion of the threaded nut and/or the threading of the threaded hollow connector are coated in an anti-seize agent capable of withstanding high temperatures.

26. The assembly according to claim 16, wherein the furnace supplies and discharges gases.

27. The assembly according to claim 16, wherein the threaded hollow connector is welded to a gas inlet/outlet pipe of the furnace.

28. The assembly according to claim 16, wherein the threaded hollow connector is welded to a support plate attached to a hearth of the furnace, and a gas inlet/outlet pipe of the furnace passes through the support plate.

29. The assembly according to claim 16, wherein the smooth hollow connector is welded to the gas inlet/outlet pipe of the stack.

30. The assembly according to claim 16, wherein the smooth hollow connector is welded to a lower end plate of the stack, and the gas inlet/outlet pipe of the stack passes through the lower end plate.

Description

BRIEF DESCRIPTION OF THE FIGURES

[0074] The invention will be better understood upon reading the following detailed description of non-limiting example embodiments thereof and upon examining the diagrammatic and partial figures of the accompanying drawing, for which:

[0075] FIG. 1 is a diagrammatic view showing the operating principle of a high-temperature solid oxide electrolyser (SOEC),

[0076] FIG. 2 shows an exploded diagrammatic view of a part of a high-temperature solid oxide electrolyser (SOEC) comprising interconnects according to the prior art,

[0077] FIG. 3 shows the architectural principle of a furnace on which a high-temperature electrolysis (SOEC) or fuel cell (SOFC) stack operating at a high temperature is placed,

[0078] FIG. 4 shows a partial, perspective view of one example of a coupling system according to the invention for a stack having SOEC/SOFC-type solid oxides, in the configuration for use thereof for coupling the stack with a furnace, and

[0079] FIGS. 5 and 6 respectively show an isolated, perspective view of coupling systems according to the invention in the assembled configuration and in the disassembled configuration of the threaded nut and of the threaded connector.

[0080] In all of these figures, identical references may represent identical or similar elements.

[0081] Moreover, the different parts shown in the figures are not necessarily displayed according to a uniform scale in order to make the figures easier to read.

DETAILED DESCRIPTION OF SPECIFIC EMBODIMENTS

[0082] FIGS. 1 to 3 have been described hereinabove in the paragraphs on the prior art and technical background of the invention. It is specified here that, in FIGS. 1 and 2, the symbols and arrows showing the supply of steam H.sub.2O, the distribution and collection of dihydrogen H.sub.2, oxygen O.sub.2, air, and the electric current, are shown for the purposes of clarity and precision, to illustrate the operation of the devices shown.

[0083] It should also be noted that all component parts (anode/electrolyte/cathode) of a given electrochemical cell are preferentially ceramics. The operating temperature of a high-temperature SOEC/SOFC-type stack typically lies in the range 600 C. to 1,000 C.

[0084] Moreover, the terms upper and lower must be understood herein to be relative to the normal orientation of a stack of the SOEC/SOFC type when in the configuration of use thereof.

[0085] FIGS. 4 to 6 show a principle for producing a coupling system 30 according to the invention. This coupling system 30 produces the coupling between a stack 20 of the SOEC/SOFC type and a furnace 10 capable of allowing for the supply and discharge of the gases in the stack 20. Generally speaking, the coupling system 30 is of the screw/nut type.

[0086] FIG. 4 shows an assembly 70 comprising a stack 20 having SOEC/SOFC-type solid oxides operating at a high temperature and a furnace 10 with which the stack 20 is coupled for the supply and discharge of the gases via coupling systems 30 according to the invention. More specifically, the assembly 70 comprises four coupling systems 30 for the two inlets/outlets provided for the stack 20.

[0087] As shown in FIGS. 4 to 6, each coupling system 30 firstly comprises a hollow threaded connector 31. This threaded connector 31 comprises a thread F1 on the outer surface thereof, and is attached to a gas inlet/outlet pipe 12. More specifically, the threaded connector 31 is attached to this gas inlet/outlet pipe 12 by TIG-type welding, which constitutes the bearing plane for the stack 20, which thus forms a part of the hearth 11 of the furnace.

[0088] Moreover, the hearth 11 of the furnace 10 comprises, in this example, a support plate 40 through which passes the gas inlet/outlet pipe 12, and the threaded connector 31 is also attached to this support plate 40, in particular by TIG-type welding or by arc welding.

[0089] The threaded connector 31 comprises an opening 41 for establishing fluid communication with the gas inlet/outlet pipe 12. It is thus positioned perpendicular to the pipe 12, forming a supply loop to the stack 20.

[0090] Moreover, each coupling system 30 further comprises a hollow smooth connector 33 having a smooth outer surface L3 and, at the lower part thereof, a rim 63 protruding relative to this smooth outer surface L3, as shown in FIG. 6.

[0091] The smooth connector 33 is attached by welding to a gas inlet/outlet pipe 52 of the stack 20 having SOEC/SOFC-type solid oxides, in particular by TIG-type welding. Moreover, the smooth connector 33 is also attached by welding to a lower end plate 25 of the stack 20, in particular by TIG-type welding or by arc welding. The gas inlet/outlet pipe 52 of the stack 20 thus passes through the lower end plate 25, as shown in FIG. 4.

[0092] Moreover, the smooth connector 33 comprises an opening 43 for establishing fluid communication with the gas inlet/outlet pipe 52 of the stack 20.

[0093] The smooth connector 33 and the threaded connector 31 each comprise an opening 44, 45 for establishing fluid communication between the two connectors 33 and 31, as shown in FIG. 6.

[0094] Furthermore, in order to allow for the assembly thereof with the gas inlet/outlet pipe 52 of the stack 20, the upper part of the smooth connector 33 comprises a bore 73, as shown in FIG. 6. Similarly, the threaded connector 31 comprises a bore 71 for the attachment thereof to the gas inlet/outlet pipe 12.

[0095] Moreover, according to the invention, each coupling system 30 further comprises a threaded nut 32 which engages with the threaded connector 31 to form a screw/nut system.

[0096] This threaded nut 32 slides relative to the smooth connector 33. More specifically, the inner surface of the threaded nut 32 comprises a first threaded portion S1 engaging with the thread F1 of the threaded connector 31 and a second smooth portion S2 in sliding contact on the smooth outer surface L3 of the smooth connector 33. More particularly, the threaded nut 32 comprises a rim 62 protruding relative to the first threaded portion S1 thereof, as shown in FIG. 6. This rim 62 comprises the second smooth portion S2. Thus, the rim 63 of the smooth connector 33 and the rim 62 of the threaded nut 32 come into contact with one another, which stops the sliding of the threaded nut 32 relative to the smooth connector 33.

[0097] In other words, the threaded nut 32, mounted such that it slides on the smooth connector 33, preferentially with clearance, will thus move down onto the smooth connector 33 and come into contact with the flat surface of the rim 63 of the smooth connector 33 by way of the flat surface of the rim 62 of the threaded nut 32. Thus, a plane-plane contact is established. The threaded nut 32 is retained by the smooth connector 33, i.e. it cannot be disassembled. The smooth connector 33 and the threaded nut 32 thus become elements of the stack 20.

[0098] Furthermore, as shown in FIG. 6, a mica gasket J2 can be placed between the rim 63 of the smooth connector 33 and the rim 62 of the threaded nut 32. This gasket J2 can resemble a mica washer inserted at the plane/plane contact in order to electrically insulate the connection where necessary. The presence of such a gasket J2 is not required if there is no need for electrical insulation.

[0099] Moreover, the nominal diameter of the threaded nut 32 preferentially lies in the range M20 to M30. It should be noted that the greater the diameter, the better the clamping, however the choice of diameter depends on the available overall dimensions. Moreover, the thicker the chosen threads, the lower the risk of bonding of the diffusion bonding type. In the case of a diameter M20, the thread pitch is 2.5 mm, and in the case of a diameter M30, the thread pitch is 3.5 mm.

[0100] Advantageously, the first threaded portion S1 of the threaded nut 32 and the thread F1 of the threaded connector 31 are coated, before placement and tightening of the connection, with a high-temperature anti-seize paste in order to ease disassembly and prevent the diffusion bonding phenomenon. This anti-seize paste further lubricates the connection and has anti-corrosion properties. It prevents the seizing and excessive wear of parts exposed to extreme temperatures or so-called corrosive atmospheres, for example in the case of heat engine threadings, tubing sets for hot gases, burners, valves, disc brakes, spark plugs, exhaust screw connectors, rollers, bolts and collars, etc. The copper-, aluminium- and graphite-based formulation thereof can protect the metal parts and ensure the disassembly thereof.

[0101] Moreover, as shown in FIGS. 5 and 6, each coupling system 30 further comprises another mica gasket J1 placed between the threaded connector 31 and the smooth connector 33. The thickness of the mica gasket J1 preferentially lies in the range 0.1 to 1 mm. This gasket J1 can take on the form of a washer punch-cut as needed. The mica has high electrical insulation properties and high thermal stability, i.e. at a continuous temperature of 900 C. and at a peak temperature of 1,000 C. During assembly, high mechanical compression is applied in order to exert a pressure on the gasket J1 that lies in the range 70 to 100 N/m.

[0102] Furthermore, during assembly, the tightening of the threaded nut 32 after having placed the mica gasket J1 causes the smooth connector 33, which will form a part of the stack 20, to move closer to the threaded connector 31, which will form a part of the furnace 10, in order to place the planar faces in contact, which will sandwich the mica gasket J1 therebetween. The same principle is applied at all of the inlets/outlets of the stack 20 such that the positioning of the stack 20 perpendicular to the four threaded connectors 31 results in the weight of the applied assembly already being sealed.

[0103] Preferentially, the smooth connector 33, the threaded nut 32 and the threaded connector 31 are made from a nickel-based superalloy, in particular of the Inconel 600 type, and/or are made from austenitic stainless steel, in particular of the 316L stainless steel type. The threaded connector 31 has a height H1 that lies in the range 15 to 30 mm and a diameter D1 that lies in the range 20 to 30 mm. Moreover, the smooth connector 33 has a height H3 that lies in the range 45 to 70 mm and a maximum diameter D3 of 30 mm, as shown in FIG. 6. The height H3 of the smooth connector 33 must be great enough for the threaded nut 32 to be removed when placing the stack 20. In the case of a threaded nut 32 of the type M20, the height H3 of the smooth connector 33 is, for example, 30 mm. In the case of a threaded nut 32 of the type M30, the height H3 of the smooth connector 33 is, for example, 40 mm.

[0104] The present invention has many advantages compared to the solutions of the prior art, which advantages are at least partially described hereinbelow.

[0105] Given that the stack 20 must be removed and transported from one furnace 10 to another, thus having a Plug & Play-type feature, the invention allows for the connections to be easily disconnected using open-ended spanners since no contact has been made between the materials.

[0106] Moreover, such a disassembly operation is facilitated by the coating of the threads of the threaded connector 31 and the tappings of the threaded nut 32, before cycling in the furnace 10, with a high-temperature anti-seize paste. The gasket surfaces can thus be surface-treated using sandpaper in order to prepare them for another cycling.

[0107] Furthermore, the seal is ensured by the pressure applied to the mica gasket J1 and not by the threading such that the invention does not require the production of optional conical threadings to improve sealing. Moreover, the assembly eliminates potential alignment and parallelism defects concerning the contact surfaces with the gasket J1 as a result of the adaptability of the connection by elastic deformation of the assembly upon pressurisation.

[0108] Furthermore, the use of mica gaskets J1 and J2 allows said gaskets to be manufactured in situ, i.e. on the geographical site where the furnace 10 is situated, for example by using a simple punch or a pair of scissors allowing the desired dimensions of the gaskets J1 and J2 to be obtained, as well as geometrical shapes that are not necessarily circular.

[0109] It goes without saying that the invention is not limited to the aforementioned examples of embodiment. Various modifications can be made thereto by a person skilled in the art.