EP2348272B1 - Regenerative heat exchanger and method for transferring heat between two solids - Google Patents

Description

The invention relates to a regenerative heat exchanger and a method for transferring heat from a first free-flowing solid to a second free-flowing solid.

Heat exchangers or heat exchangers are known. For example, the DE 30 27 187 A1 a recuperative heat exchanger for indirect heat transfer between free-flowing solids. This recuperative heat exchanger consists of a bundle of mutually parallel tubes, wherein adjacent tubes abut each other at least on one side surface. The tube bundle is arranged horizontally and rotatable about an axis of rotation. In the tubes conveying ribs are fixed so that the free-flowing solid is conveyed by the rotation of the tubes about the axis of rotation parallel to the extension direction of the tubes through the respective tube. Through a part of the tubes, the first solid is conveyed in one direction, while at the same time the second solid is conveyed in the opposite direction through the other part of the tubes. In this case, the heat is at least partially transferred from the warmer solid through the tube wall to the colder solid.

GB 322 601 A discloses a regenerative heat exchanger having a heat exchange surface for transferring heat from a first material (exhaust gas) to a second substance (air). A positioning device can change the position of the heat exchanger surface between a heat absorption position and a heat release position. The first substance (exhaust gas) moves through an exhaust passage in a direction of movement from a first side to a second side of the heat exchange surface. The second substance (air) moves through an air channel along the heat exchanger surface from the second side to the first side of the heat exchanger surface. After heating a part of the heat exchanger surface in the gas channel, the heat exchanger surface is rotated and the heated part is positioned in the air duct, while the cooled part is moved from the air duct into the gas duct. In each position of the heat exchanger surface therefore takes place a heat absorption in the gas duct and a heat emission in the air duct.

DE 32 25 838 A1 shows a heat exchanger, which has substantially the same structure as that of GB 322 601 A ,

Based on this, a heat exchanger and a method for heat transfer between free-flowing solids to be created with improved efficiency.

This object is achieved by a regenerative heat exchanger with the features of claim 1, by a heat exchanger assembly having the features of claim 12 and by the method having the features of claim 13.

The heat exchanger according to the invention is designed as a regenerative heat exchanger. The first free-flowing solid and the second free-flowing solid are moved successively over the heat exchanger surface of the heat exchanger for heat transfer. The hot first free-flowing solid releases its heat to the heat exchanger surface during its movement along the heat exchanger surface. Then, when the second free-flowing solid is passed over the heat exchanger surface, it absorbs the heat from the heat exchanger surface. In this way, the heat is at least partially transferred from the first free-flowing solid to the second free-flowing solid. There Both solids are brought into contact with the same heat exchanger surface, very high levels of heat transfer efficiency can be achieved.

The heat exchanger according to the invention also has a positioning device by means of which the position of the heat exchanger surface between a heat absorption position and a heat release position can be changed. To heat the heat exchanger surface, this is brought by the positioning in its heat receiving position. The first free-flowing solid moves in a direction of movement from a first side to a second side of the heat exchanger surface. Preferably, the two sides of the heat exchanger surface are arranged one above the other in the vertical direction. The heat exchanger surface heats up more in the region of its first side than in the region of its second side. This is due to the fact that the first solid cools continuously as it passes through the heat exchanger while delivering the heat to the heat exchanger surface. After the heat exchanger surface has been heated sufficiently, the supply of the first free-flowing solid is stopped in the heat exchanger and the positioning moves the heat exchanger surface in the heat release position. In this case, the heat exchanger surface changes its position such that the subsequently supplied second free-flowing solid first impinges on the less heated second side of the heat exchanger surface and is forwarded from there along the heat exchanger surface to its first side.

Preferably, the first side of the heat exchanger surface is arranged in the heat absorption position in the vertical direction seen over the second side, while the second side of the heat exchanger surface in the heat release position located vertically above the first page. In both positions, the respective solid trickles exclusively or at least supported by gravity along the heat exchanger surface from top to bottom.

By rotating the heat exchanger surface, it is achieved that the temperature gradient between the solid material passed through the heat exchanger and the heat exchanger surface remains approximately the same at each point of the heat exchanger surface. The regenerative heat exchanger works as it were according to the "countercurrent principle". This ensures a high efficiency in the heat transfer from the first to the second free-flowing solid. Both solids are passed one after the other over the same, entire heat exchanger surface.

The regenerative heat exchanger or the heat exchanger arrangement comprising a plurality of regenerative heat exchangers and the method according to the invention can advantageously be used in conjunction with a calciner. The first hot, free-flowing solid is a calcium oxide (CaO) enriched solid. The second free-flowing solid is preferably a calcium carbonate (CaCO ₃ ) enriched solid. The heat transfer can take place between the first solid stream led out of the calciner and the second solid stream leading into the calciner. The regenerative heat exchanger can therefore be an integral part of the calciner.

In some embodiments of the heat exchanger surface, it is advantageous to provide a heat exchanger housing surrounding the heat exchanger surface. The heat exchanger housing is provided in particular for embodiments of the heat exchanger surface which are not fastened to one another Parts, such as loosely packed packing. Such fillers can be very easily filled into the heat exchanger housing. The heat exchanger housing does not have to be completely closed for this purpose. It can have a grid-like structure. Housing openings must be designed in their shape and / or size so that the filler can not fall through and can be held in the heat exchanger housing. For example, perforated wall elements or grid elements may be used to form housing openings. In each case at least at a first and a second location, a housing opening is present, so that can be fed or removed via the two housing openings of each passing through the heat exchanger solid.

The positioning device can displace the heat exchanger housing together with the heat exchanger surface between the heat release position and the heat absorption position. In particular, the first and the second housing openings in each case exchange their positions. This makes it possible to achieve a compact design of the regenerative heat exchanger, which requires little space. In a simple embodiment of the positioning device, this can be designed as a rotating device which rotates the heat exchanger surface or the heat exchanger housing with the heat exchanger surface between the two positions. The axis of rotation preferably runs transversely to the direction of movement of the solids through the heat exchanger. For example, the axis of rotation can be arranged approximately horizontally. Between the two positions of the heat exchanger surface, this can then be rotated, for example, by 180 degrees.

At least part of the heat exchanger surface may be formed by arranged in the heat exchanger housing packing. These fillers serve the size of the heat exchanger surface so that the heat exchange surface provided for contact with the respective solid is large for a given volume. This ensures that a sufficient passage cross-section for the passage of the respective solid remains. On the design of the shape and size of the packing not only the heat exchanger surface can be increased, but also the residence time of the passed solid and thus the contact time between the solid and the heat exchanger surface varies and be set as desired.

The packing may form a solid structure or matrix and be immovably connected relative to each other. In this case, can be dispensed with a heat exchanger housing.

Advantageously, the filler can have spacer means, so that the distance between adjacent packing ensures a sufficiently large passage cross-section for the passage of the respective solid. As a spacer means may be used by the filler projecting projections, such as pins, rods, discs, disc segments or the like.

As filler, for example, balls or polyhedra can be used. These may alternatively or in addition to spacer means comprise one or more through holes through which the solid in question can be passed.

Wavy or multiply angled plates or sheets can also be used as the packing. Alternatively or additionally, it is also possible to use rods running transversely to the direction of movement of the respective solid as filling bodies.

Conveniently, the same solid inlet and / or outlet is used to introduce the first and second solids into the heat exchanger. The heat exchanger surface is arranged between Feststoffeinlass- and solids outlet. Between the heat exchanger surface or the heat exchanger housing and the solids inlet may also be provided a Feststoffverteileinrichtung which serves to distribute the solid in a surface which extends transversely to the direction of movement of the solid along the heat exchanger surface. This ensures a uniform contact of the heat exchanger surface with the solid. In particular, the solids distribution device distributes the solid in a substantially horizontal area. As a solid distribution device, for example, serve a distribution tray. This distribution trough can be fluidized, so that a particularly homogeneous fluidized bed is formed and distributes the solids uniformly over the surface, which can then trickle out of the distribution trough to the heat exchanger surface via a multiplicity of overflow openings.

• Figur 1 ein Blockschaltbild einer einen Kalzinator und einen Karbonator aufweisenden Kraftwerkanlage,
• Figur 2 eine Draufsicht auf eine Wärmetauscheranordnung zwischen Kalzinator und Karbonator in schematischer Darstellung,
• Figur 3 die in Figur 2 dargestellte Wärmetauscheranordnung gemäß Schnittlinie B-B,
• Figur 4 ide in Figur 2 dargestellte Wärmetauscheranordnung gemäß Schnittlinie A-A,
• Figur 5 ein erstes Ausführungsbeispiel einer Wärmetauscherfläche mit gewellten Platten,
• Figur 6 ein zweites Ausführungsbeispiel einer Wärmetauscherfläche mit abgewinkelten Platten,
• Figur 7 ein drittes Ausführungsbeispiel einer Wärmetauscherfläche mit quer zur Bewegungsrichtung der Feststoffe verlaufenden Stäben,
• Figur 8 ein viertes Ausführungsbeispiel einer Wärmetauscherfläche mit einer gitterähnlichen Struktur,
• Figur 9 kugelförmige Füllkörper mit Abstandhaltemitteln in Form von Stiften zur Bildung einer Wärmetauscherfläche nach einem fünften Ausführungsbeispiel und
• Figur 10 kugelförmige Füllkörper mit Durchgangslöchern zur Bildung einer Wärmetauscherfläche nach einem sechsten Ausführungsbeispiel.

Further advantages and preferred embodiments of the invention will become apparent from the dependent claims and the description. In the description, preferred embodiments of the invention will be described with reference to the accompanying drawings. Show it:

• FIG. 1 1 is a block diagram of a power plant comprising a calciner and a carbonator;
• FIG. 2 a top view of a heat exchanger assembly between calciner and carbonator in a schematic representation,
• FIG. 3 in the FIG. 2 illustrated heat exchanger assembly according to section line BB,
• FIG. 4 ide in FIG. 2 illustrated heat exchanger assembly according to section line AA,
• FIG. 5 A first embodiment of a heat exchanger surface with corrugated plates,
• FIG. 6 A second embodiment of a heat exchanger surface with angled plates,
• FIG. 7 A third embodiment of a heat exchanger surface with transverse to the direction of movement of the solids rods,
• FIG. 8 A fourth embodiment of a heat exchanger surface with a grid-like structure,
• FIG. 9 Spherical fillers with spacer means in the form of pins to form a heat exchanger surface according to a fifth embodiment and
• FIG. 10 Spherical packing with through-holes for forming a heat exchanger surface according to a sixth embodiment.

FIG. 1 shows a block diagram of a power plant 20 with a furnace 21, such as a steam generator firing. The resulting exhaust gas contains carbon dioxide (CO ₂ ), which is fed to a carbonator 22 in which the CO ₂ is absorbed by a sorbent in the form of calcium oxide (CaO) and reacts to calcium carbonate (CaCO ₃ ). The carbonate stream 22 containing, the calcium oxide-containing or consisting of solid stream is a first free-flowing solid F1.

Via a solids separator 23, a solids flow of a second free-flowing solid F 2, which contains or consists of the calcium carbonate, is fed from the carbonator 22 to a calciner 24. In a calciner firing 25, a mixture of fuel B and an oxidizer, eg, pure oxygen or air L, is combusted to heat the calciner 24 to reach the calcination temperature of about 900 degrees Celsius. In calciner 24, the calcium carbonate is split again into calcium oxide (CaO) and carbon dioxide (CO ₂ ). The calcium oxide is fed to the carbonator 22 in the first solid F1.

The concentrated CO ₂ gas produced in the calciner 24 can be compressed after cooling and purification and stored, for example, underground. For cooling, a heat exchanger 26 can serve, so that the heat contained in the CO ₂ can be converted into useful energy. Part of the CO ₂ -containing exhaust gas can be supplied from the calciner 24 via a return line 27 to the carbonator 22 together with the CO ₂ from the exhaust gas of the furnace 21. In the return line 27, a further heat exchanger 28 may be present. Further, before the supply of the exhaust gas to the carbonator 22, a flue gas desulfurization unit 29 and a control valve 30 for controlling the Carbonator 22 supplied amount of gas be present. Another flue gas desulfurization unit 31 and a further valve 32 may be present in the connection line 33 between the furnace 21 and the carbonator 22. Optionally, the flue gas desulfurization unit 31 and the control valve 32 can also be used for the exhaust gas flow conducted through the return line 27, as shown in dashed lines in FIG FIG. 1 is shown. In this case, the flue gas desulfurization unit 29 and the control valve 30 can be omitted.

The exhaust gases largely freed of CO ₂ in the carbonator 22 are fed via an exhaust pipe 34 to a chimney or cooling tower 35. In the exhaust pipe 34, a further heat exchanger 36, a further control valve 37 and a dust separator 38 may be arranged.

The arrangement of the heat exchangers 26, 28, 36, the flue gas desulfurization units 29, 31, the control valves 30, 32, 37 and the dust separator 38 represent a preferred embodiment of the power plant 20, but can be changed. For example, the order of the mentioned components in a line can be changed. It is also possible to combine functionally identical units in order to simplify the construction of the system. It is also possible to provide a further dust separator 39 in the connecting line 33 following the firing 21 of the power plant 20.

Between carbonator 22 and calciner 24, at least one regenerative heat exchanger 45 is provided according to the invention. The regenerative heat exchanger 45 serves for the at least partial transfer of heat from the first free-flowing solid F1, which is supplied to the carbonator 22 from the calciner 24, to the second free-flowing solid F2, which is the calciner 24 from the carbonator 22nd is supplied. In the preferred embodiment, the calciner 24 has a heat exchanger unit 46 with a plurality of and, for example, three regenerative heat exchangers 45 connected in parallel. The regenerative heat exchangers 45 serve to preheat the second free-flowing solid F2, so that fuel B and oxygen carrier (O ₂ ) can be saved in the calciner firing 25. For this purpose, the regenerative heat exchangers 45 transfer heat of the hot first free-flowing solid F1 to the second free-flowing solid F2.

A schematic representation of the heat exchanger assembly 46 with the means for supplying and discharging the solids F1, F2 is shown schematically in the FIGS. 2 to 4 shown.

Each regenerative heat exchanger 45 of the heat exchanger assembly 46 is assigned a solids inlet 47. Each solids inlet 47 is connected via a respective first inlet pipe 48 to a first inlet valve device 49. The first inlet valve device 49 is seated between the first inlet tubes 48 and a siphon 50 of a solids separator of the calciner 24, not shown in detail. In the siphon 50, the first free-flowing solid F1 is collected.

Furthermore, each of the solids inlets 47 is connected via a second inlet pipe 51 and a second inlet valve device 52 to the solids separator 23 of the carbonator 22, in which the second free-flowing solid F 2 is located. By way of the two inlet valve devices 49, 52, either the first free-flowing solid F1 or the second free-flowing solid F2 can be fed to each of the regenerative heat exchangers 45 independently of one another.

The supply of solids F1, F2 takes place in the preferred embodiment exclusively by gravity. Below each inlet opening 47, a distributor trough 55 is arranged in each heat exchanger 45, which serves for the areal substantially horizontal distribution of the respectively supplied solid F1 or F2. The distribution trough 55 can be easily fluidized for better distribution of solids and has a plurality of along its surface overflow openings 56, as shown schematically in FIG FIG. 4 is shown.

Seen in the vertical direction below the distributor trough 55 and vertically below the respective solids inlet 47, the heat exchanger surface 57 of the regenerative heat exchanger 45 is arranged. In the preferred embodiment, the heat exchanger surface 57 is within a heat exchanger housing 58. The heat exchanger housing 58 can be omitted in embodiments of the heat exchanger 45, in which the heat exchanger surface 57 has a rigid or rigid structure and can be rotatably supported without housing, for example, in heat exchanger surfaces with plate-shaped elements ( FIGS. 5, 6 ). The heat exchanger surface 57 is in the Figures 3 and 4 only schematically indicated by a hatching. On the heat exchanger surface 57 will be later in connection with the FIGS. 5 to 10 discussed in more detail.

Each regenerative heat exchanger 45 or each heat exchanger assembly 46 is associated with a positioning device 60. The positioning device 60 serves to displace the heat exchanger surface 57 between a heat absorption position I and a heat release position II. In the embodiment described here, the heat exchanger surface 57 is fixedly connected to the heat exchanger housing 58, wherein the positioning device 60, the heat exchanger housing 58 moves together with the heat exchanger surface 57. For this purpose, the heat exchanger housings 58 are preferably rotatably mounted on a respective holder 62 about a substantially horizontally extending axis of rotation 61. The positioning device 60 is designed in this case as a rotator 63. The three heat exchanger housings 58 can be moved independently between their two positions I, II.

Below the heat exchanger surface 57 and, according to the example vertically below the solids inlet 47, a solids outlet 64 is present, to which an outlet valve device 65 is assigned. Via the outlet valve device 65, the solids outlet 64 of the heat exchanger 45 is connected either to a first outlet line 66 to the carbonator 22 or to a second outlet line 67 to the calciner 24. Depending on which solid F1, F2 is passed through the heat exchanger 45, the outlet valve device 65 is adjusted.

The holder 62 is configured in the form of a heat exchanger housing 58 surrounding outer housing 70 in the preferred embodiment. In the region of the heat exchanger housing 58, a rotation region 71 is present in the interior of the outer housing 70, which enables the rotation of the heat exchanger housing 58 about the axis of rotation 61. The rotation area 71 is designed as a cylindrical cavity, for example.

According to the embodiment FIG. 1 The heat exchanger housing 58 has a cylindrical contour with a cylinder axis extending in the direction of the axis of rotation 61. The base of the cylindrical heat exchanger housing 58 is indicated by a polygon, such as a hexagon. The base could alternatively be circular or be elliptical. In principle, the housing shape of the heat exchanger housing 58 is freely selectable.

The heat exchanger surface 57 of each heat exchanger 58 has a first side 72 and a relative to the axis of rotation 61 diametrically opposite second side 73. In the heat absorption position I of the heat exchanger surface 57, its first side 72 is assigned to the solids inlet 47 and its second side 73 to the solids outlet 64. Therefore, the first side 72 is located vertically above the second side 73. For displacement of the heat exchanger surface 57 from the heat receiving position 1 in the heat release position 2, the rotator 63 rotates the relevant heat exchanger surface 57 by 180 degrees. The two sides 72, 73 therefore exchange their positions. In the heat release position II, therefore, the second side 73 is assigned to the solids inlet 47 and the first side 72 to the solids outlet 64.

The first side 72 of the heat exchanger surface 57 is arranged adjacent to a first housing opening 75 and the second side 73 adjacent to a second housing opening 76 in the heat exchanger housing 58. Through the housing openings 75, 76 of the respective solid F1, F2 depending on position I, II of the heat exchanger housing 58 can be supplied or removed. The in the FIGS. 5 and 6 drawn arrows indicate the direction of movement of the heat exchanger 45 passing through the solid F1 or F2, wherein the heat exchanger surface 57 is for example in each case in their heat absorption position I.

The heat exchanger surface 57 can be designed differently. Some embodiments are in the FIGS. 5 to 10 shown. According to the first embodiment FIG. 5 the heat exchanger surface 57 is formed by a plurality of mutually parallel corrugated plates or sheets 79. Instead of the corrugated plates 79 also multiply angled plates or sheets 80 may be used, as in FIG. 6 is shown schematically. Due to the corrugated or angled shape of the plates 79, 80, the direct trickling through of the solids F1, F2 is prevented. The plates 79, 80 form obstacles, so to speak, which redirect the solid in its direction of movement over and over again in order to extend the contact time between the solid F1, F2 and the heat exchanger surface 57. The plates or plates 79, 80 represent provided in the heat exchanger housing packing 81.

At an in FIG. 7 illustrated third embodiment, the heat exchanger housing 58 is filled with a plurality of rod-shaped packing 81. The rods 82 forming the packing 81 are arranged transversely to the direction of movement R of the solids F1, F2 through the heat exchanger. The rods 82 may pass through the heat exchanger housing partially or completely from one side wall to the opposite side wall. Spacer means 83 are provided around the rods 82 to space the rods 82 apart so as to provide a sufficient passage area for the solids F1, F2. The rods 82 then need not be fixedly connected to the heat exchanger housing 58. The spacer means 83 are formed in this embodiment of annular discs 84 which surround the rods 82.

In a further, fourth exemplary embodiment, the heat exchanger surface 57 is formed by a grid-like structure 85. Again, transverse to the direction of movement R extending rods 82 are present, which are fixed in the direction of movement R extending holding rods 85 in position.

In the FIGS. 9 and 10 further alternative possibilities for packing 81 are shown. The packing 81 are each configured as an approximately spherical body. In the embodiment according to FIG. 9 has each filler 81 radially distributed in different directions projecting pins 86, the spacer means 83 form. The pins are preferably distributed over the entire circumference of the packing 81. The respective solid F1 or F2 can flow through the heat exchanger housing 58 between the spherical packing 81 and the pins 86.

Also in FIG. 10 shown packing 81 are configured in the form of balls. They each have a plurality of through holes 87 to allow the passage of the first and second solid F1 and F2 through the heat exchanger housing 58.

In a modification to the embodiment variants of the heat exchanger surface 57 described here, combinations of the described packing 81 may also be used. For example, spherical packing 81 may also be used between the plates 79, 80.

The heat exchanger 45 according to the invention or the heat exchanger arrangement 46 consisting of three regenerative heat exchangers 45 operates as follows:
In the heat absorption position I of the heat exchanger surface 57, the first free-flowing solid F1 is supplied to the regenerative heat exchanger 45 via the first inlet pipe 48. The distributor trough 55 distributes the first free-flowing solid F1 horizontally evenly. Through the overflow openings 56 in the distributor pan 55, the first free-flowing solid F1 trickles through the first housing opening 75 It then impinges on the heat exchanger surface 58 and moves along the heat exchanger surface 57 to the second housing opening 76. There it exits the heat exchanger housing 58 and becomes the carbonator 22 via the solids outlet 64 and outlet valve means 65 of the first outlet conduit 66 fed. After sufficient heating of the heat exchanger surface 57, the first inlet valve device 49 stops the supply of the first free-flowing solid F1. During the heating of the heat exchanger surface 57, its first side 72 was below the solids inlet 47, while its second side 73 was associated with the solids outlet 64. Therefore, the first side 72 has heated more than the second side 73. The temperature of the heat exchanger surface 57 decreases continuously from the first side 72 to the second side 73.

Via the positioning device 60, the heat exchanger surface 57 is displaced into its heat release position II, for example rotated about the axis of rotation 61. Now, the less warm second side 73 is associated with the solids inlet 47 and the more heated first side 72 with the solids outlet 64. The second free-flowing solid F2 is now fed to the regenerative heat exchanger 45 via the second inlet valve device 52, with the second free-flowing solid F2 increasingly heating as it moves along the heat exchanger surface 57. Since the temperature of the heat exchanger surface 57 in the heat release position II in the direction of movement R of the second free-flowing solid F2 continuously increases from the second side 73 to the first side 72, an approximately constant temperature difference between the second free-flowing solid F2 and the heat exchanger surface 57 on the the entire path of the second free-flowing solid F2 along the heat exchanger surface 57 can be achieved. The regenerative Heat exchanger 45 operates, so to speak, according to the "countercurrent principle". The second free-flowing solid F2 of the second outlet line 67 is fed to the calciner 24 via the outlet valve device 65.

Since the heat exchanger surface 57 increasingly cools in the heat release position II, the supply of the second free-flowing solid F2 is stopped after a certain time and the positioning device 60 brings the heat exchanger surface back into its heat absorption position I. The warmer first side 72 of the heat exchanger plate is now back to the solids inlet assigned. The first free-flowing solid F1 therefore moves from the warmer first side to the less hot second side 73 of the heat exchanger surface 57. Therefore, during the entire movement, the temperature difference between the first free-flowing solid F1 and the heat exchanger surface 57 is approximately constant.

The procedure described is continued cyclically.

Like this in the FIGS. 2 to 4 a plurality of regenerative heat exchangers 45 form a heat exchanger unit 46. Preferably, at least three heat exchangers 45 are combined in a heat exchanger unit 46. It is possible to achieve continuous streams both for the first free-flowing solid F1, and for the second free-flowing solid F2. For this purpose, there are the regenerative heat exchanger 45 a heat exchanger unit 46 in different states: heat absorption position I, heat release position II or switching state between the two positions I, II. As long as one of the regenerative heat exchanger 45 is in its heat absorption position I, takes at least one of the other regenerative heat exchanger 45th the heat release position II, as in FIG. 3 is shown. The third regenerative heat exchanger 45 of the heat exchanger assembly 46 is in the switching state between the two positions I, II. In the switching state, during the displacement movement of the heat exchanger surface 57 between the two positions I, II, no solids supply to the heat exchanger 45 takes place. By providing three parallel-connected regenerative heat exchangers 45 in a heat exchanger unit 46, a continuous flow of both solids F1, F2 can nevertheless be ensured.

The invention relates to a regenerative heat exchanger 45 and to a method for transferring heat from a first free-flowing solid F1 to a second free-flowing solid F2. The regenerative heat exchanger 45 has a heat exchanger surface 57. The heat exchanger surface 57 can be switched between a heat absorption position I and a heat release position II by a positioning device 60. In the heat absorption position I trickles a first free-flowing solid F1 along the heat exchanger surface 57 from a first side 72 to a second side 73. In this case, the heat exchanger surface 57 heats up, with their temperature continuously increases from the first side 72 to the second side 73. After heating the heat exchanger surface 57, the positioning device 60 moves the heat exchanger surface 57 into the heat release position II, in which the second free-flowing solid F 2 to be heated is passed along the heat exchanger surface 57. The second free-flowing solid F2 moves from the less warm second side 73 to the warmer first side 72. The solids F1, F2 preferably move vertically downwards in a direction of movement R solely by gravity along the heat exchanger surface 47. During the entire movement of the respective free-flowing solid F1, F2 along the heat exchanger surface 57, the temperature difference between the free-flowing solid F1, F2 and the heat exchanger surface 57 is approximately constant, resulting in a continuous heat transfer between the heat exchanger surface 57 and the respective solid F1, F2.

In a preferred heat exchanger arrangement 46, three regenerative heat exchangers 45 are provided, each heat exchanger 45 being in a different state: one heat exchanger 45 takes the heat absorption position I, the other heat exchanger 45 the heat release position II and the third heat exchanger 45 a switching state between the heat absorption position I. and the heat release position II.

LIST OF REFERENCE NUMBERS

20

Power plant

21

heating

22

carbonator

23

solids

24

calciner

25

Kalzinatorfeuerung

26

Heat exchanger

27

Return line

28

Heat exchanger

29

Rauchgasentschwefelungseinheit

30

control valve

31

Rauchgasentschwefelungseinheit

32

control valve

33

connecting line

34

exhaust pipe

35

Fireplace / cooling tower

36

Heat exchanger

37

control valve

38

dust collector

39

dust collector

45

Regenerative heat exchanger

46

heat exchanger unit

47

Solids inlet

48

First inlet pipe

49

First inlet valve device

50

Siphon v. 24

51

Second inlet pipe

52

Second inlet valve device

55

distribution pan

56

Overflow opening

57

Heat exchanger surface

58

heat exchanger housing

60

Positioniereirichtung

61

axis of rotation

62

bracket

63

rotator

64

solids outlet

65

outlet valve

66

First outlet line

67

Second outlet pipe

70

outer casing

71

rotation range

72

First page

73

Second page

75

First housing opening

76

Second housing opening

79

Corrugated plate

80

Angled plate

81

packing

82

Rod

83

Spacer means

84

disc

85

retaining bar

86

pen

87

Through Hole

I

Heat receiving position

II

Heat position

B

fuel

F1

First free-flowing solid

F2

Second free-flowing solid

L

air

R

movement direction

O ₂

oxygen

Co ₂

carbon dioxide

Claims (13)

1. Regenerative heat exchanger for transferring heat from a first free-flowing solid (F1) to a second free-flowing solid (F2),
   with a heat exchanger surface (57) which is arranged between a solids inlet (47) and a solids outlet (64),
   wherein the same solids inlet (47) is used for introduction of the first free-flowing solid (F1) and the second free-flowing solid (F2) into the heat exchanger, and the same solids outlet (64) is used for discharge of the first free-flowing solid (F1) and the second free-flowing solid (F2) from the heat exchanger,
   with a positioning device (60) by means of which the position of the heat exchanger surface (57) can be changed between a heat-absorbing position (I) and a heat-emitting position (II),
   wherein in the heat-absorbing position (I), a first side (72) of the heat exchanger surface (57) is assigned to the solids inlet (47) and a second side (73) to the solids outlet (64), and wherein in the heat-emitting position (II), the second side (73) is assigned to the solids inlet (47) and the first side (72) to the solids outlet (64),
   wherein in the heat-absorbing position (I) of the heat exchanger surface (57), the first free-flowing solid (F1) flows at least supported by gravity from top to bottom in a movement direction (R) along the heat exchanger surface (57) from the first side (72) to the second side (73) of the heat exchanger surface (57), and
   wherein in the heat-emitting position (II), the second free-flowing solid (F2) flows at least supported by gravity from top to bottom along the heat exchanger surface (57) substantially from the second side (73) to the first side (72) of the heat exchanger surface (57).
2. Regenerative heat exchanger according to claim 1, characterised in that a heat exchanger housing (58) with a first housing opening (75) and a second housing opening (76) is provided, in which housing the heat exchanger surface (57) is arranged.
3. Regenerative heat exchanger according to claim 2, characterised in that in order to move the heat exchanger surface (57) between the heat-absorbing position (I) and the heat-emitting position (II), the positioning device (30) moves the heat exchanger housing (58) together with the heat exchanger surface (57) arranged therein.
4. Regenerative heat exchanger according to claim 3, characterised in that the two housing openings (75, 76) exchange their positions on movement of the heat exchanger surface (57) between its two positions (I, II).
5. Regenerative heat exchanger according to claim 1, characterised in that the positioning device (60) is configured as a turning device (63) which turns the heat exchanger surface (57) about a rotation axis (61) which runs transversely to the movement direction (R) of the solids (F1, F2) along the heat exchanger surface (57).
6. Regenerative heat exchanger according to claim 2, characterised in that at least part of the heat exchanger surface (57) is formed by filler bodies (81) arranged in the heat exchanger housing (58).
7. Regenerative heat exchanger according to claim 6, characterised in that the filler body (81) comprises spacer means (83) for maintaining a minimum distance from the respective adjacent filler bodies (81).
8. Regenerative heat exchanger according to claim 6, characterised in that each filler body (81) comprises at least one passage hole (87).
9. Regenerative heat exchanger according to claim 6, characterised in that corrugated or angled plates (79, 80) are used as filler bodies (81).
10. Regenerative heat exchanger according to claim 6, characterised in that rods (82) arranged transversely to the movement direction (R) of the solids (F1, F2) are used as filler bodies (81).
11. Regenerative heat exchanger according to claim 1, characterised in that a solids distribution device (55) is provided between the solids inlet (47) and the heat exchanger surface (57), by means of which device the respective supplied solid (F1, F2) is distributed evenly over the surface transversely to its movement direction (R).
12. Heat exchanger arrangement with at least two regenerative heat exchangers (45) according to any of the preceding claims, wherein the heat exchanger surface (57) of at least one of the heat exchangers (45) is in the heat-absorbing position (I) while the heat exchanger surface (57) of at least one other heat exchanger is in the heat-emitting position (II).
13. Method for transferring heat from a first free-flowing solid (F1) to a second free-flowing solid (F2) by means of a regenerative heat exchanger (45) according to any of claims 1 to 11,
    wherein, in a heat-absorbing position (I) of the heat exchanger surface (57), the first free-flowing solid (F1) is conducted in a movement direction (R) along the heat exchanger surface (57) from a first side (72) to a second side (73) of the heat exchanger surface (57),
    wherein after heating, the heat exchanger surface (57) is moved into a heat-emitting position (II) in which the second free-flowing solid (F2) is conducted along the heat exchanger surface (57) from the second side (73) to the first side (72) of the heat exchanger surface (57).

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