EP3165865A1 - Heat exchanger - Google Patents

Abstract

Heat exchanger (1) for molten salt applications for transferring heat from a first fluid (F 1) to a second fluid (F 2), with an outer jacket (15) through which the first fluid (F 1) can flow Tube bundle (6) through which the second fluid (F 2) can flow, wherein the tube bundle (6) is arranged in the outer jacket (15) and can be flowed around to transfer the heat from the first fluid (F 1) Tube bundle (6) has an inner jacket (13) which is axially displaceably mounted in the outer jacket (15) in a longitudinal direction (L) thereof and wherein for storing the inner jacket (13) in the outer jacket (15) between the inner shell (13) and the outer jacket (15) at least one replaceable bearing element (22) is arranged.

Description

The invention relates to a heat exchanger.

With the aid of a heat exchanger, heat can be transferred from a first fluid to a second fluid or vice versa. Such heat exchangers are used, for example, in process engineering plants, for example for hydrogen production, power plants, in particular solar power plants, or the like. Such a heat exchanger has an outer jacket in which the first fluid circulates. In the outer shell, a tube bundle is provided, that is flowed around by the first fluid. The tube bundle is flowed through by the second fluid. The US 4,186,049 A . US 4,090,554 A . US 6,561,265 B2 . US 2011/0240261 A1 . US 4,045,286 A . US 6,701,711 B1 and US 6,877,508 B2 describe such heat exchangers.

Against this background, the object of the present invention is to provide an improved heat exchanger.

Accordingly, a heat exchanger for molten salt applications is proposed for transferring heat from a first fluid to a second fluid. The heat exchanger comprises an outer jacket through which the first fluid can flow, a tube bundle through which the second fluid can flow, the tube bundle being arranged in the outer jacket and the heat transferable to transfer the heat from the first fluid, the tube bundle an inner shell axially slidably supported in the outer shell in a longitudinal direction thereof, and an exchangeable bearing member being disposed between the inner shell and the outer shell for supporting the inner shell in the outer shell.

A molten salt application is understood to mean an application of the heat exchanger in which heat is transferred from one molten salt, which may be the first fluid, to another fluid, for example the second fluid, or vice versa. The heat exchanger can therefore also be referred to as a molten salt heat exchanger become. In particular, at least one replaceable bearing element is provided. Under an exchangeable bearing element is a bearing element to understand that non-destructive, especially without tools or with the help of tools, is interchangeable. In particular, the bearing element is connected cohesively neither to the inner shell nor to the outer jacket. Since the first fluid and the second fluid may have different temperatures, different thermal expansion between the outer shell and the tube bundle may occur. Characterized in that the inner jacket is mounted by means of the bearing element in the outer shell, these heat-related different dimensions of the tube bundle and the outer shell can be compensated without causing mechanical stresses in the heat exchanger. This increases the operational reliability and the life of the heat exchanger. The fact that the bearing element is replaceable, the heat exchanger is still very easy and comfortable to maintain.

According to one embodiment, a plurality of replaceable bearing elements are provided, which are arranged distributed uniformly over a circumference of the outer shell.

Preferably, at least three bearing elements are provided. Alternatively, four, five or more bearing elements may be provided.

According to a further embodiment, the replaceable bearing element is made of a soft metal.

For example, the replaceable bearing element may be made of aluminum, lead, bronze or copper or have aluminum, lead, bronze or copper. Alternatively, the replaceable bearing element may also be made of graphite or have graphite. As a result, good sliding properties are always guaranteed.

According to a further embodiment, the replaceable bearing element is received in a receiving element.

The receiving element is preferably box-shaped and preferably has four side walls between which the replaceable bearing element is received.

The bearing element is preferably inserted only in the receiving element and not firmly connected thereto. As a result, the bearing element can be exchanged particularly easily.

According to a further embodiment, the receiving element is attached to the outer jacket.

For example, the receiving element may be welded to the outer jacket. Alternatively, the receiving element may be formed, for example, as provided in the outer shell recess.

According to a further embodiment, the bearing element is adapted to slide on a sliding element.

The sliding element is preferably plate-shaped. The bearing element and the sliding element can each be cylindrically curved.

According to a further embodiment, the sliding element is fastened to the inner jacket.

For example, the sliding element is welded to the inner shell. The sliding element may also be formed integrally with the inner shell.

According to a further embodiment, the outer jacket has an outer tube section extending longitudinally therefrom, wherein a diameter of the outer tube section is smaller than a diameter of the outer jacket.

In particular, an outer diameter of the outer tube portion is smaller than an outer diameter of the larger jacket. Preferably, the outer pipe section extends out of a curved end face of the outer shell. Preferably, the outer tube section is formed integrally with the outer jacket. For example, the outer tube section may be welded to the outer jacket.

According to a further embodiment, the inner jacket has a longitudinally extending inner tube section, wherein a diameter of the inner tube section is smaller than a diameter of the inner jacket.

Preferably, an outer diameter of the inner pipe section is smaller than an outer diameter of the inner shell. Preferably, the diameter of the inner shell is smaller than the diameter of the outer shell and the diameter of the inner pipe section is smaller than the diameter of the outer pipe section. Preferably, the inner pipe section extends out of a curved end face of the inner shell.

According to a further embodiment, the inner tube section is axially displaceably mounted in the outer tube section in the longitudinal direction, wherein the interchangeable bearing element is arranged for storing the inner tube section in the outer tube section between the inner tube section and the outer tube section.

Preferably, a plurality of replaceable bearing elements is arranged between the inner tube section and the outer tube section. The bearing elements may for example be connected to the outer pipe section.

According to a further embodiment, the outer jacket has a removable cover, which closes the outer tube section on the front side.

The lid may close a maintenance opening of the outer shell.

According to a further embodiment, the lid is cup-shaped.

The lid preferably has a bottom, a tubular base portion and a flange disposed opposite the bottom. With the help of the flange, the lid is connectable to the outer tube section. For this purpose, a flange may be provided on the outer pipe section. Between the flange of the outer tube portion and the flange of the lid, a sealing device be provided. The sealing device may be a weld ring seal or weld ring lip seal.

According to a further embodiment, the inner pipe section is at least partially disposed in the lid.

As a result, the inner tube section is accessible when removing the lid of the outer tube section. This facilitates the maintenance of the heat exchanger.

According to a further embodiment, the replaceable bearing element is at least partially disposed in the lid.

For example, the receiving elements of the bearing elements are connected to the lid. As a result, the bearing elements can be exchanged particularly easily when removing the lid.

According to a further embodiment, the first fluid is a molten salt and the second fluid is a thermal oil or an organic heat carrier.

For example, the molten salt may include alkali metal hydrates, nitrites, nitrates, sulfates, carbonates, chlorides, hydroxides, bromides, thiocyanates, fluorides or combinations of these. Preferably, during operation of the heat exchanger, the molten salt and the second fluid are fed under pressure to the heat exchanger and depressurized. In this case, for example, the first fluid having an inlet temperature of about 390 ° C and an outlet temperature of about 290 ° C and the second fluid having an inlet temperature of about 280 ° C and an outlet temperature of 380 ° C.

Further possible implementations of the heat exchanger also include not explicitly mentioned combinations of features or embodiments described above or below with regard to the exemplary embodiments. The expert will also add individual aspects as improvements or additions to the respective basic form of the heat exchanger.

Further advantageous embodiments and aspects of the heat exchanger are the subject of the dependent claims and the embodiments of the heat exchanger described below. Furthermore, the heat exchanger will be explained in more detail with reference to the accompanying figures.

Fig. 1 shows a schematic sectional view of an embodiment of a heat exchanger;

Fig. 2 shows a schematic sectional view of the heat exchanger according to the section line II-II of Fig. 1 ;

Fig. 3 shows the detail view III according to Fig. 1 ;

Fig. 4 shows the detail view IV according to Fig. 3 ;

Fig. 5 shows the view V according to Fig. 3 ; and

Fig. 6 shows a schematic partial perspective view of the heat exchanger according to Fig. 1 ,

In the figures, the same or functionally identical elements have been given the same reference numerals, unless stated otherwise.

The Fig. 1 shows a schematic sectional view of an embodiment of a heat exchanger 1 for transferring heat from a first fluid F ₁ to a second fluid F ₂ . The Fig. 2 shows a schematic sectional view of the heat exchanger 1 according to the section line II-II of Fig. 1 , The Fig. 3 shows the detail view III according to Fig. 1 , The Fig. 4 shows the detail view IV according to the Fig. 3 , The Fig. 5 shows the view V according to Fig. 3 , The Fig. 6 shows a schematic perspective partial view of the heat exchanger 1. Hereinafter, the Fig. 1 to 6 simultaneously referred to.

The heat exchanger 1 is suitable for molten salt applications. Therefore, the heat exchanger 1 may also be referred to as a molten salt heat exchanger. The heat exchanger 1 is for process plants, such as plants for generating energy from solar radiation, refineries, plants for hydrogen production, power plants or the like. The heat exchanger 1 comprises a tubular first head 2 with an inlet 3 and an outlet 4. The head 2 may be closed at the front side with a cover 5. In the inlet 3, the second fluid to be heated F _{2 flows} . The second fluid F ₂ is supplied to the inlet 3 under pressure. In this case, the second fluid F _2, for example, have a temperature of 280 ° C. The second fluid F ₂ may be, for example, a thermal oil or an organic heat carrier.

From the outlet 4, the heated second fluid F _{2 flows,} for example, at a temperature of 380 ° C without pressure. Conversely, the second fluid F _{2 can} flow into the outlet 4 and flow out through the inlet 3. In this case, the outlet 4 is referred to as inlet and the inlet 3 as outlet. The inlet 3 and the outlet 4 can by a in the Fig. 1 not shown partition plate be fluidly separated from each other. The partition plate may be in the orientation of Fig. 1 be arranged horizontally.

The heat exchanger 1 has a in the Fig. 3 shown tube bundle 6, which has a plurality of tubes 7 to 10. The number of tubes 7 to 10 is arbitrary. For example, the tube bundle may include 50 to 200 tubes 7 to 10. The tubes 7 to 10 are connected to the first head 2 such that the second fluid F _{2 flows} from the inlet 3 through the tubes 9, 10 in the direction of a second head 11 of the heat exchanger 1. At the second head 11, the tube bundle 6 is connected to a closure plate 12. For example, the tubes 7 to 10 are welded to the end plate 12. The tubes 7 to 10 terminate at the end plate 12. Connected to the end plate 12 is an inner shell 13 of the heat exchanger 1. The end plate 12 and the inner shell 13 enclose a space 14 through which the second fluid F ₂ flows and deflects therein becomes. In this case, the second fluid F _{2 flows} through the tubes 9, 10 into the space 14 and from the space 14 via the tubes 7, 8 and the outlet 4 again from the heat exchanger 1 from.

The heat exchanger 1 further includes an outer jacket 15 having an inlet 16 and an outlet 17. The first fluid F ₁ , which is preferably a molten salt, flows into the inlet 16 under pressure. In this case, the first fluid F _{1 have} a temperature of about 390 ° C. The molten salt may contain alkali metal hydrates, Nitrites, nitrates, sulfates, carbonates, chlorides, hydroxides, bromides, thiocyanates, fluorides, or combinations of these. In particular, the molten salt may have a melting temperature of over 300 ° C. The first fluid F ₁ flows from the inlet 16 in the direction of the second head 11 and from this back towards the outlet 17 to flow out of the heat exchanger 1. When flowing out of the heat exchanger 1, the first fluid F _{1 may have} a temperature of about 290 ° C. When flowing out of the heat exchanger 1, the first fluid F _{1 is} preferably depressurized.

For guiding the first fluid F ₁ in the outer jacket 15, a partition plate 18 is provided therein, which is in the orientation of Fig. 1 is arranged horizontally. The partition plate 18 extends from the first head 2 in a longitudinal direction L of the outer shell 15 in the direction of the second head 11 Fig. 2 shows the partition plate 18 can be arranged rotated relative to a horizontal h by an angle α. The angle α can be for example 45 °. The partition plate 18 may be fixedly connected to the outer jacket 15, in particular welded, be. The partition plate 18 may optionally be insulated.

The heat exchanger 1 further comprises vertically arranged partition plates 19, 20, which are alternately attached either to the outer jacket 15 and / or to the partition plate 18. Like in the Fig. 1 represented by arrows, the first fluid F _{1 is} guided along the horizontally disposed partition plate 18 and thereby guided around the vertically arranged partition plates 19, 20. The tubes 7 to 10 of the tube bundle 6 are passed through the partition plates 19, 20. In this case, the tubes 7 to 10 with respect to the partition plates 19, 20 in the longitudinal direction L axially displaceable. By diverting the first fluid F ₁ by means of separator plates 19, 20 a special good flowing around the tube bundle 6 with the first fluid F ₁ is achieved. As the Fig. 2 Furthermore, 15 optional stiffening rings 21 may be provided on the outside of the outer jacket 15 on the outside.

As the Fig. 3 shows, the inner jacket 13 is disposed within the outer shell 15. Due to the different temperatures of the first fluid F ₁ and the second fluid F ₂ , there may be different length expansions in the longitudinal direction L of the outer jacket 15 and the tube bundle 6. For this reason, the inner shell 13 in the longitudinal direction L is axially displaceable in stored the outer jacket 15. The inner jacket 13 is mounted floating on the second head 11 in the outer jacket 15. Therefore, the second head 11 may also be referred to as a floating head.

For storing the inner shell 13 in the outer shell 15 is between the inner shell 13 and the outer shell 15, an exchangeable bearing element 22 (FIG. Fig. 5 ) intended. The number of bearing elements 22 is arbitrary. Preferably, a plurality of such replaceable bearing elements 22 are provided which are distributed uniformly over a circumference u _{15 of} the outer shell 15. For example, three, four, five, six or more bearing elements 22 may be provided. Under interchangeable is to be understood in the present case that the bearing elements 22 are destructively removable from the heat exchanger 1. As a result, the bearing elements 22 can be easily replaced when worn.

The bearing elements 22 are preferably provided on the outer jacket 15 or attached thereto. The replaceable bearing elements 22 are preferably made of a soft metal such as aluminum, copper, bronze or lead or have a soft metal. Alternatively, the bearing elements 22 may also be made of graphite or have graphite. The bearing elements 22 can each be accommodated in receiving elements 23. The receiving elements 23 are box or box-shaped. The bearing elements 22 may be inserted without further attachment in the receiving elements 23. The receiving elements 23 are attached to the outer jacket 15. The receiving elements 23 may be provided in the outer jacket 15 recesses or be welded, for example, on the outer jacket 15. The bearing elements 22 are adapted to slide on corresponding sliding elements 24. The sliding elements 24 may be attached to the inner shell 13. For example, the sliding elements 24 may be welded to the inner shell 13.

As the Fig. 3 Furthermore, the outer jacket 15 has an outer tubular section 25 extending out of the longitudinal direction L out of this. The outer tube section 25 is preferably formed in one piece with the outer jacket 15. The outer tube section 25 extends out of a curved end face 26 of the outer jacket 15. A diameter d ₂₅ , in particular a Inner diameter of the outer tube portion 25 is smaller than a diameter d ₁₅ , in particular an outer diameter, of the outer jacket 15. The outer jacket 15 has a removable cover 27 which closes the outer tube portion 25 frontally. For example, a flange 28 may be provided on the outer pipe section 25 and a flange 29 corresponding to the flange 28 may be provided on the cover 27. The flanges 28, 29 are sealed together.

The Fig. 4 shows the sealing of the flanges 28, 29. The flanges 28, 29 and the outer jacket 15 and the lid 27 may be made for example of a chromium-molybdenum steel. In the flanges 28, 29 a plurality of through holes 30, 31 may be provided, can be passed through the fastening means 32 such as screws. With the help of the fastening means 32, the flanges 28, 29 are pressed axially against each other. Between the flanges 28, 29, a sealing device 33 is provided. The sealing device 33 is a so-called welding ring seal or welding ring lip seal. In the area of the sealing device, the flanges 28, 29 are each provided with a fastening element 34, 35. The fastening elements 34, 35 are applied, for example, by build-up welding and made of a nickel- and / or molybdenum-based alloy. The sealing device 33 has a first sealing element 36 which is fixedly connected to the fastening element 34 and a second sealing element 37 which is fixedly connected to the second fastening element 35.

Between the sealing elements 36, 37, an optional sealing means 38 may be provided. The sealing means 38 seals the sealing device 33, for example during a pressure test. The sealing elements 36, 37 may optionally be welded together. For this purpose, each sealing element 36, 37 has a semicircular welding section 39, 40. The welding sections 39, 40 can be firmly connected to one another by a weld 41. During operation of the heat exchanger 1, a heat-related relative movement of the flanges 28, 29 to each other by the elastically deformable welding portions 39, 40 are compensated.

Now returning to Fig. 3 For example, the lid 27 has a cup-shaped geometry with a tubular base portion 42 on which the flange 29 is provided and a bottom 43 opposite the flange 29. The bottom 43 is curved. The inner shell 13 has a longitudinal direction L in this extending inner tube portion 44. The inner tube section 44 extends out of a curved end face 45 of the inner jacket 13. A diameter d _{44 of} the inner tube portion 44 is smaller than a diameter d _{13 of} the inner shell 13. Further, the diameter d _{44 is} smaller than the diameter d ₂₅ and the diameter d ₁₃ is smaller than the diameter d _15th

As the Fig. 3 shows, the inner tube portion 44 is axially slidably mounted in the outer tube portion 25 in the longitudinal direction L, wherein for supporting the inner tube portion 44 in the outer tube portion 25 between the inner tube portion 44 and the outer tube portion 25, the bearing elements 22 are arranged. Furthermore, the bearing elements 22 can be arranged at least partially in the cover 27. Also, the inner pipe section 44 is at least partially disposed in the lid 27.

The inner tube section 44 is closed at the end with a cover 46. The cover 46 is fastened to a flange 47 provided on the end of the inner pipe section 44. Between the plate-shaped cover 46 and the flange 47 is also in the Fig. 4 shown sealing device 33 is provided. An outer diameter of the lid 46 is smaller by about 5 mm than an inner diameter bounded by the bearing elements 22. As a result, the cover 27 can be removed via the cover 46. In this case, the receiving elements 23 of the bearing elements 22 can be firmly connected to the cover 27. As a result, a particularly simple replacement of the bearing elements 22 is possible.

Characterized in that the inner jacket 13 is floatingly mounted in the outer jacket 15 stresses due to different thermal expansions can be prevented. Thermal bypasses or heat leaks are effectively reduced in the heat exchanger 1 described above. The molten salt can move freely through the heat exchanger 1. By the use of the partition plate 18, an effective heat transfer is possible, wherein the partition plate 18 may be optionally isolated. The heat exchanger 1 is particularly easy to maintain because the lid 27 is easily removable. The heat exchanger 1 is particularly pressure-insensitive by the use of the sealing device 33. The heat exchanger 1 is also particularly inexpensive to produce.

Although the present invention has been described with reference to embodiments, it is variously modifiable.

Used reference signs:

1

heat exchangers

2

head

3

inlet

4

outlet

5

cover

6

tube bundle

7

pipe

8th

pipe

9

pipe

10

pipe

11

head

12

End plate

13

coat

14

room

15

coat

16

inlet

17

outlet

18

separating plate

19

separating plate

20

separating plate

21

stiffening ring

22

bearing element

23

receiving element

24

Slide

25

pipe section

26

front

27

cover

28

flange

29

flange

30

Through Hole

31

Through Hole

32

fastener

33

sealing device

34

fastener

35

fastener

36

sealing element

37

sealing element

38

sealant

39

welding portion

40

welding portion

41

Weld

42

base section

43

ground

44

pipe section

45

front

46

cover

47

flange

F ₁

fluid

F ₂

fluid

₁₃

diameter

₁₅

diameter

d ₂₅

diameter

d ₄₄

diameter

H

horizontal

L

longitudinal direction

u ₁₅

scope

α

angle

Claims (15)

Heat exchanger (1) for molten salt applications for transferring heat from a first fluid (F ₁ ) to a second fluid (F ₂ ), with an outer jacket (15) through which the first fluid (F ₁ ) can flow Tube bundle (6) through which the second fluid (F ₂ ) can flow, wherein the tube bundle (6) is arranged in the outer jacket (15) and can be flowed around to transfer the heat from the first fluid (F ₁ ) Tube bundle (6) has an inner jacket (13) which is axially displaceably mounted in the outer jacket (15) in a longitudinal direction (L) thereof and wherein for storing the inner jacket (13) in the outer jacket (15) between the inner shell (13) and the outer jacket (15) an exchangeable bearing element (22) is arranged. Heat exchanger according to claim 1, wherein a plurality of interchangeable bearing elements (22) is provided, evenly distributed over a circumference (U ₁₅₎ of the outer jacket (15) are arranged. Heat exchanger according to claim 1 or 2, wherein the replaceable bearing element (22) is made of a soft metal. Heat exchanger according to one of claims 1-3, wherein the replaceable bearing element (22) is received in a receiving element (23). A heat exchanger according to claim 4, wherein the receiving element (23) is fixed to the outer jacket (15). Heat exchanger according to one of claims 1-5, wherein the replaceable bearing element (22) is adapted to slide on a sliding element (24). A heat exchanger according to claim 6, wherein the sliding member (24) is fixed to the inner shell (13). A heat exchanger according to any one of claims 1-7, wherein the outer jacket (15) has an outer pipe section (25) extending outwardly therefrom in the longitudinal direction (L) and having a diameter (d ₂₅ ) of the outer pipe Pipe section (25) is smaller than a diameter (d ₁₅ ) of the outer jacket (15). A heat exchanger as claimed in claim 8, wherein the inner shell (13) has an inner tubular section (44) extending therefrom in the longitudinal direction (L) and wherein a diameter (d ₄₄ ) of the inner tubular section (44) is smaller than a diameter (d ₁₃ ). of the inner shell (13). A heat exchanger according to claim 8 or 9, wherein the inner pipe section (44) is axially slidably mounted in the outer pipe section (25) in the longitudinal direction (L) and wherein for supporting the inner pipe section (44) in the outer pipe section (25) between the inner tube section (44) and the outer tube section (25), the replaceable bearing element (22) is arranged. Heat exchanger according to one of claims 8 - 10, wherein the outer jacket (15) has a removable cover (27) which closes the outer pipe section (25) at the end. A heat exchanger according to claim 11, wherein the lid (27) is pot-shaped. Heat exchanger according to claim 11 or 12, wherein the inner pipe section (44) is at least partially disposed in the cover (27). Heat exchanger according to one of claims 11-13, wherein the replaceable bearing element (22) is at least partially disposed in the cover (27). Heat exchanger according to one of claims 1-14, wherein the first fluid (F ₁ ) is a molten salt and the second fluid (F ₂ ) is a thermal oil or an organic heat carrier.

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