DE102013200209A1 - Device for recovering energy from hot slab, has heat exchanger made of elastic, that is provided with cooling passage through which heat transfer medium or coolant passage is flowed - Google Patents

Abstract

The device has a heat exchanger (100) that is made into contact with slab. The heat exchanger made of elastic, is provided with a cooling passage (110) through which heat transfer medium or coolant passage is flowed. The heat exchanger is provided with pressing structures (130-1-130-3) that are provided in the form of field elements or hydraulic cylinders, for pressing surface elements (120-1-120-3). The heat transfer coefficient during contact of heat exchanger and surface of the slab is 1000 W/m2K. An independent claim is included for method for operating the device for recovering energy from hot slab.

Description

The invention relates to a device for energy recovery from a still warm slab. The device essentially has at least one heat exchanger, which can be brought into contact with the slab. Moreover, the invention relates to a method for operating such a device.

State of the art

Continuous casting plants for casting steel are well known in the art. They comprise a mold into which liquid metal, in particular a molten steel, is poured, and a strand guide arranged downstream of the mold, in which a cast strand drawn out of the mold is guided and solidifies. After its solidification of the cast strand is typically divided into easier to handle sections, so-called slabs or divided.

The molten steel typically has a temperature of about 1,600 ° C and the cast strand after its solidification and after leaving the strand guide typically still has a temperature of about 1,000 ° C.

A freshly poured and still so warm slab represents insofar a heat storage.

The recovery of energy from such a still hot slab is basically known in the art; she will z. B. described in the document DE 10 2004 023 031 A1 . DE 30 19 714 A1 . DE 26 22 722 . WO 2011/138171 A2 . JP 59 198883 A or JP 60040657 A ,

Particularly relevant to the subject matter of the present invention is the German Offenlegungsschrift DE 10 2009 031 557 A1 , From this publication, it is known to assign the freshly cast slabs heat exchanger in order to use the stored heat in the slabs can. It is proposed to form the heat exchangers, for example, as a plate heat exchanger. The heat exchangers may be assigned to the hot slabs during their transport to a slab store as well as in the slab store itself. It is mentioned that for optimum use of heat, good heat transfer between slab and heat exchanger should be made. It is also known from this document to aim for the highest possible outlet temperature of the heat medium from the heat exchanger; This can be suitably adjusted by suitably changing the flow rate of the heat transfer medium in the heat exchanger. On the other hand, targeted cooling rates should often be set for the stored slabs. This is advantageously achieved in that different outlet temperatures are specified for the heat transfer medium. These target temperatures can be suitably changed over the cooling time in order to be able to dynamically set predetermined cooling curves for the slabs. A process model monitors and controls the cooling process, preferably by means of a continuous measurement of the inlet and outlet temperature of the heat transfer medium or the cooling medium in the heat exchanger.

In the prior art, it is also known that the cast strand or the slabs are not uniformly cooled during their cooling time at each point of their surface; this often leads to tensions and deformations of the slab; their surfaces are then no longer flat. These deformations of the slab have the disadvantage that a plate-shaped heat exchanger with a flat contact surface touches the deformed slab only locally or punctually, which adversely affects the heat transfer coefficient between slab and heat exchanger.

The invention has the object of developing a known device for recovering energy from a still hot slab and a method for operating such a device to the effect that the contact and thus the heat transfer coefficient between slab and heat exchanger is improved.

This object is solved by the subject matter of claim 1. This is characterized in that the heat exchanger is elastic.

The term "hot slab" means, in particular, the slab which has not yet cooled to room temperature after casting. The temperature of the slab TB is then typically in the range of 1200 ° C> TB> 50 ° C.

Due to the invention claimed elastic design of the heat exchanger ensures that the heat exchanger to the possibly deformed, d. H. not flat surface of the slab snuggles, so that the contact surface and thus the heat transfer coefficient between the slab and heat exchanger is increased.

According to a first embodiment of the heat exchanger is formed in its planar extension of a plurality of surface elements for this purpose, which are preferably coupled together. At least some of the Surface elements are associated pressing elements for pressing the surface elements against the surface of the slab. As a result of this division of the entire effective area of the heat exchanger into individual smaller area elements, the heat exchanger is quasi-point elastic, because these individual area elements can be pressed individually against the part of the surface of the slab assigned to them.

The pressing of the surface elements is carried out with pressure elements, the z. B. are formed in the form of spring elements or hydraulic cylinders.

There may be a controller for driving the pressing elements so that the surface elements are engageable with a predetermined pressure against the surface of the slab.

As an alternative to the just described embodiment of the heat exchanger from a plurality of individual surface elements, the heat exchanger according to a second embodiment can also be designed in the form of a temperature-stable heat-conducting and elastic cushion.

The cushion is then in its interior, but outside its cooling channels, with a filling medium, for. B. filled with air or with a hydraulic fluid, and it may be provided a control for adjusting the filling of the pad with the filling medium such that the pad presses with a predetermined pressure against the surface of the slab.

The two variants of the heat exchanger just described, d. H. the first heat exchanger, formed from the plurality of surface elements, and the second heat exchanger, formed in the form of the elastic pad, can both be applied to different surfaces of one and the same slab for recovering energy from the slab.

The above object of the invention is also achieved by the device according to claim 8, which aims at a combination of at least one heat exchanger according to the invention with a slab. The advantages of this solution according to claim 8 correspond to the advantages mentioned above with reference to the device according to the invention.

According to one embodiment, it is advantageous that - when the heat exchanger is formed from one of the plurality of surface elements - the control is designed to control only those pressing elements whose associated surface elements of the surface of the slab opposite. Conversely, those pressing elements whose associated surface elements are outside the surface of the slab should not be controlled. In this respect, the claimed embodiment of the heat exchanger allows flexible adaptation to different surface sizes of the slab.

In order to further increase the heat transfer coefficient, it is advantageous that those sides of the slab, z. B. whose narrow sides, which are not covered by one of the heat exchanger according to the invention or are in contact with it, are thermally insulated.

By contacting the slab with the heat exchangers according to the invention, a heat transfer coefficient of at least 1000 W / m ² × K is advantageously achieved. This advantageously allows a desired cooling of the slab within about 1 hour.

The above object is further achieved by a method for operating the device according to claim 13. This method comprises the following steps: contacting the still hot slab with the at least one elastic heat exchanger; as long as the temperature TB of the slab is still above a predetermined threshold temperature TBS: flow through the heat exchanger with a heat transfer medium, wherein the heat transfer medium due to the heat emitted from the slab from a first inlet temperature TE1 to a first outlet temperature TA1 heats up with TB> TA1> TBS; and - after the temperature TB of the slab has fallen below the predetermined threshold temperature TBS -: flowing through the heat exchanger with a cooling medium, wherein the cooling medium heats up from a second inlet temperature TE2 to a second outlet temperature TA2 due to the residual heat of the slab with: TE2 < TE1 and TA2 <TA1 with, for example, TA1> 250 ° C and TBS 250 ° C.

The claimed subdivision of the method steps for a slab temperature above the threshold value TBS and a slab temperature below the threshold value TBS is based on the following consideration:

As long as the temperature of the slab is above said threshold temperature TBS and the first outlet temperature TA1 is also above this threshold temperature TBS, an energy recovery from the still-warm slab is energetically meaningful; It is then worthwhile in particular the forwarding of the heat transfer medium to an energy recovery system, eg. B. an Organic Rankine Cycle ORC - or a Kalina plant for power generation. Below the threshold temperature TBS makes the Transmission of the heat transfer medium energetically no longer meaning. It may then be useful to deliberately cool down the slab, ie, for example, to cool down to a predetermined temperature as quickly as possible; This is achieved, for example, in that, instead of the heat transfer medium, a cooling medium is now used which, when passing through the heat exchanger, is significantly cooler than the heat transfer medium. The cooling of the cooling medium can, for. B. by an external cooling source. Substantially, the heat transfer medium and the cooling medium may basically be the same medium, as stated above, but the temperature of the cooling medium, when used in the heat exchanger, is lower than the temperature of the heat transfer medium.

Further advantageous embodiments of the invention are the subject of the dependent claims.

The description is attached to six figures, wherein

1 the temperature profile of the slab under different boundary conditions;

2 a manipulator for loading and unloading the heat exchanger sites;

3 Heat exchangers in Sandwitch design with different slabs;

4 a detailed view 1 with additions;

5 an even more partial view 4 ; and

6 shows the heat exchanger in the form of a pad according to the invention.

The invention will be described in detail below with reference to the mentioned figures. In all figures, the same technical features are designated by like reference numerals.

At the end of the description, the content of the priority document is reproduced again. The 1 to 3 refer to the documents giving priority to the priority and are therefore only described at the end of the description.

4 shows an enlarged section of the 1 ,

In the 4 The features shown are described below with reference to the more detailed 5 explained in more detail.

5 shows the heat exchanger according to the invention 100 according to the first embodiment, according to which it - in its planar extent - from a plurality of surface elements 120-1 . 120-2 and 120-3 is constructed. Each of these surface elements is a pressure element, here for example a hydraulic cylinder 130-1 . 130-2 . 130-3 associated with individually adjusting the surface elements against the surface of a slab 200 , As in 4 shown, the slab can be stored both vertically and horizontally. The pressing elements are using a first controller 140 individually controlled. The control is preferably carried out such that each of the surface elements 120-1 . 120-2 . 120-3 is pressed against the surface of the slab with a predetermined pressure, which is preferably given the same amount for all surface elements.

In 5 is further to recognize that the heat exchanger 100 and in particular its individual surface elements 120-1 . 120-2 . 120-3 with a cooling channel 110 are traversed, which is traversed either by a heat transfer medium or a cooling medium. Substantively, the two media can be identical; However, they have in each case a different inlet temperature; the temperature of the cooling medium is lower than that of the heat transfer medium. The conceptual distinction between heat transfer medium and cooling medium is made to express that when operating the heat exchanger with a heat transfer medium, the primary goal is to absorb the heat of the freshly cast slab and supply it to an energy recovery system. In contrast, the primary intention in the operation of the heat exchangers with a cooling medium is to cool the slab as quickly as possible, ie dissipate as much heat as possible from the slab in as short a time as possible.

The cooling channels of the individual surface elements can be connected to each other, as in 5 is shown schematically. In addition, the individual surface elements may be mechanically coupled to each other, as in 5 through the continuous cooling channel 110 is also shown schematically. The coupling of the surface elements 120-1 . 120-2 . 120-3 can also exist in the connection of their cooling channels. In any case, the coupling should, however, be elastic or flexible in order to be able to ensure the optionally required adjustment of adjacent surface elements to different positions / heights.

6 shows a second embodiment of the heat exchanger according to the invention, after which it is designed in the form of a pad. The material of the pillow must be temperature stable be able to withstand the high temperatures that the slab still has at least at the beginning of their cooling process. Alternatively, the pad material used would have to be cooled. This applies both to the shell of the pad and to the filling medium used inside the pad. The pillow is also from a cooling channel 110 traversed, which is also traversed either by the heat transfer medium or by the cooling medium. It can be a second controller 150 be provided for adjusting the filling of the pad with the filling medium such that the pad with a predetermined pressure against the surface of the slab, in 5 deliberately not drawn, pressed. Due to the good heat-conducting properties of the shell of the pad and its filling material, the heat is released from the surface of the slab well to the heat transfer medium or the cooling medium. Due to its elasticity, the pillow adapts well to the possibly uneven surface of the slab 200 at.

It can be provided that, in particular, the two broad sides of one and the same slab are contacted with different heat exchangers, firstly with the heat exchanger according to the first embodiment and secondly with the heat exchanger according to the second embodiment. The not contacted with heat exchangers parts of the surface of the slab are preferably thermally insulated.

The inventive construction of the heat exchanger according to the first or second embodiment ensures that the heat transfer coefficient at the contact of the heat exchanger with the surface of the slab is at least 1000 W / m ² × K.

The content of the priority application is reproduced below. This is fully the subject of the present description.

1. Sandwich heat exchanger for slab cooling

• – Abkühlung erfolgt in der Regel im Brammenlager in Stapeln, d. h. sie dauert vergleichsweise lange, so dass das Brammenlager groß dimensioniert werden muss. Außerdem werden Brammenstapel durch benachbarte heiße Brammenstapel in der Abkühlung behindert.
• – Die Energie der Brammen geht komplett verloren.
• – Die Brammen kühlen durch die ungleichmäßigen thermischen Randbedingungen ungleichmäßig ab und verformen sich zum Teil.
• – Wegen der hohen Energieverluste muss für die Halle eine geeignete Ventilation vorhanden sein.

Problems with the cooling of slabs are

• - Cooling is usually in the slab stock in stacks, ie it takes a comparatively long time, so that the slab stock must be large dimensions. In addition, slab stacks are obstructed by adjacent hot slab stacks during cooling.
• - The energy of the slabs is completely lost.
• - The slabs cool unevenly due to the uneven thermal boundary conditions and deform in part.
• - Because of the high energy losses must be available for the hall a suitable ventilation.

To speed up cooling, slabs are also cooled in water basins, so that the slab bearings can be dimensioned smaller. However, even with the use of water cooling, the thermal energy of the slab is lost unused.

Ideas of the invention

According to the invention, it is proposed to reduce the cooling time of the slabs and at the same time to recover energy from the slabs. This is done according to the invention by heat exchangers, which are facing the two broad sides of the slab and use the thermal energy of the slab to heat the heat transfer medium. This ensures that both broad sides of the slabs cool evenly and no distortion of the slab arises because of uneven temperature distribution. It is characteristic that only one slab of 2 the two broad sides of the slabs opposite heat exchangers is cooled.

After cooling to a certain temperature, the slab is removed again and can continue to cool alone in the stack.

(Fig. 1 = Fig. 1: Cooling diagram for single slab, slab stack)

• – Direkter Kontakt der Wärmetauscher mit den Brammen, um höhere Wärmeübergangszahlen zu erzielen und um mehr Wärme aus der Bramme nutzen zu können. Das kann z. B. durch Verwenden von Wärmetauschern mit planen Flächen geschehen.
• – Anpressen der Wärmetauscher zur Erhöhung der Kontaktfläche und Erhöhung der Wärmeübergangszahlen
• – An einer gewissen Temperatur, ab der die Wärme der Bramme nicht mehr effektiv genutzt wird, kann durch Umschalten der Wärmetauscher von einem Wärmeträgermedium zu einem Kühlmedium (z. B. auf einen Kühlwasserkreis) für eine schnelle weitere Abkühlung der Brammen gesorgt werden.
• – Aufteilung der Wärmetauscherfläche in mehrere Teilflächen, die durch hydraulisches Zu- und Abschalten der Brammengröße angepasst werden kann.

Ideas that improve the invention

• - Direct contact of the heat exchangers with the slabs, in order to achieve higher heat transfer rates and to be able to use more heat from the slab. This can z. B. done by using heat exchangers with flat surfaces.
• - Pressing the heat exchanger to increase the contact area and increase the heat transfer coefficients
• - At a certain temperature, from which the heat of the slab is no longer effectively used, can be provided by switching the heat exchanger from a heat transfer medium to a cooling medium (eg, a cooling water circuit) for rapid further cooling of the slabs.
• - Distribution of the heat exchanger surface in several sub-areas, which can be adjusted by hydraulic connection and disconnection of the slab size.

• – Die Bramme liegt waagerecht im Sandwich; der untere Wärmetauscher ist z. B. mit fester Verrohrung in den Boden integriert.
• – Isolierung der stirnseitigen Flächen der Brammen
• – Translatorische Elemente, um die Wärmetauscher möglichst flächig an die Brammen zu drücken (z. B. Hydraulikzylinder)

Ideas for constructive realization and improvement horizontally arranged heat exchanger broadsides

• - The slab lies horizontally in the sandwich; the lower heat exchanger is z. B. integrated with solid piping in the ground.
• - Insulation of the frontal surfaces of the slabs
• - Translational elements in order to press the heat exchangers as extensively as possible against the slabs (eg hydraulic cylinders)

• – Die Bramme steht auf einer Schmalseite (in Längsrichtung der Bramme) im senkrechten Sand-Wärmetauscher (Bilder bzw. 2–4)
• – Isolierung der stirnseitigen Flächen der Brammen
• – Translatorische Elemente, um die Wärmetauscher möglichst flächig an die Brammen zur drücken (z. B. Hydraulikzylinder)
• – Elastische Bettung des Wärmetauschers auf einem Hubkissen um eine große Kontaktfläche zwischen Wärmetauscher und Bramme zu erzeugen. Das Hubkissen presst durch Aufbringen eines Luft- oder hydraulischen Druckes den Wärmetauscher an die Bramme.
• – Tragkonstruktion, in der mehrere Paare von Wärmetauschern als Sandwiche senkrecht untergebracht sind (Multisandwich) (Bilder bzw. 2–4).
• – Manipulator, der die Brammen aufnimmt, das Multisandwich beschickt und entleert bzw. entlädt (Bilder bzw. 2 und 3).

Ideas for constructive realization and improvement - vertically arranged heat exchanger broadsides

• - The slab is on a narrow side (in the longitudinal direction of the slab) in the vertical sand heat exchanger (pictures or 2 - 4 )
• - Insulation of the frontal surfaces of the slabs
• - Translational elements in order to press the heat exchangers as extensively as possible against the slabs (eg hydraulic cylinders)
• - Elastic bedding of the heat exchanger on a lifting cushion to produce a large contact surface between the heat exchanger and slab. The lifting cushion presses the heat exchanger to the slab by applying an air or hydraulic pressure.
• - Support structure, in which several pairs of heat exchangers are housed as sandwiches vertically (multi-sandwich) (pictures or 2 - 4 ).
• - Manipulator that receives the slabs, the multi-sandwich feeds and empties or discharges (pictures or 2 and 3 ).

2. Ideas for constructive realization and improvements of the multi-sandwich construction by using modules

• • Einer transportfähigen Tragkonstruktion, der Transport kann z. B. mit dem Kran oder über Schienen und Rollen erfolgen, die mit dem Fundament Kraft- oder Formschlüssig verbunden sind.
• • Die Tragkonstruktion kann so ausgebildet werden, dass: – die zu kühlende Bramme zwischen den zwei Wärmetauschern steht. Die Tragkonstruktion hat die Form eines U – die Tragkonstruktion zwischen zwei zu kühlende Brammen steht. Die Tragkonstruktion hat die Form eines I.
• • Die Tragkonstruktion enthält: – zwei Wärmetauscher, je eine für die Brammenbreitseite – die Regelarmatur zur Steuerung des Wärmeträgermediums – Messsensoren für Temperatur, Druck und Menge – Rohrleitungen und/oder Schläuche für das Wärmeträgermedium – Je eine Absperrarmatur für die Zu- und Abfuhrleitung – Schnellschlusskupplungen zur Verbindung mit der fest installierten Rohrleitung auf dem Fundament

A module consists of:

• • A transportable support structure, the transport can z. B. done with the crane or rails and rollers that are connected to the foundation force or positive fit.
• • The supporting structure can be designed in such a way that: - the slab to be cooled stands between the two heat exchangers. The supporting structure has the shape of a U - the supporting structure stands between two slabs to be cooled. The supporting structure has the shape of an I.
• • The support structure contains: - two heat exchangers, one each for the slab side - the control valve for controlling the heat transfer medium - temperature, pressure and flow sensors - pipes and / or hoses for the heat transfer medium - one shut-off valve each for the supply and discharge line - quick-release couplings for connection to the permanently installed pipeline on the foundation

• • Andrücken der Wärmetauscher an die Bramme um eine höhere Wärmeübergangszahl zu erzielen.
• • Einsatz von translatorischen Elementen zum Vergrößern des Abstandes zwischen den Wärmetauschern beim Ein- und Ausladen der Brammen zum Schutz der Wärmetauscher, sowie zum Anpressen der Wärmetauscher an die Bramme in der Abkühlphase.
• • Elastische Bettung der Wärmetauscher um eine größere Kontaktfläche zwischen Bramme und Wärmetauscher zu erzielen. Hierdurch wird die Wärmeabfuhr an die Wärmetauscher vergrößert, besonders bei nicht ebenen Brammen.

Further improvements

• • Pressing the heat exchangers against the slab for a higher heat transfer coefficient.
• • Use of translational elements to increase the distance between the heat exchangers when loading and unloading the slabs to protect the heat exchangers and to press the heat exchangers against the slab in the cooling phase.
• • Elastic bedding of the heat exchangers to achieve a larger contact surface between slab and heat exchanger. As a result, the heat dissipation is increased to the heat exchanger, especially for non-planar slabs.

3. Influencing the cooling rate of the slab by changing the flow temperature of the heat exchangers.

• • By raising and lowering the flow temperature of the heat exchangers, the cooling of the slabs can be controlled. This can be done by: - Switching of 3-way valves (at least two each for flow and return) between two circuits that are connected to a heat exchanger and operated with different flow temperature. - Operated by moving the slab from a cooling position in the heat carrier with high flow temperature to a new position in which the heat exchangers are operated with lowered flow temperature.

4. Improvement of the utilization of the energy dissipated via the heat exchangers

In order to efficiently operate the heat removal from the slabs via the heat exchangers for later energy recovery, it is necessary to control the heat transfer media. The aim is to obtain a high heat flow with small fluctuations over a long time. This is achieved by a simulation model.

• • Produktionsleistung der Gießmaschine (Gießdauer und Gießgeschwindigkeit)
• • Brammengeometrie
• • Eintrittstemperatur der Brammen
• • Anzahl Lagerplätze und maximale Verweilzeit der Brammen im Wärmetauscher
• • Zieltemperatur der Bramme
• • Temperaturintervall des Wärmeträgermediums am Austritt

Fixed sizes are:

• • Production capacity of the casting machine (casting time and casting speed)
• • Slab geometry
• • inlet temperature of the slabs
• • Number of storage bins and maximum residence time of the slabs in the heat exchanger
• • Target temperature of the slab
• • Temperature interval of the heat transfer medium at the outlet

Varying sizes are:
Flow and / or return temperature of the heat transfer medium
Mass flow of the heat transfer medium
Adjustment force of the translational elements for influencing the heat transfer between slab and heat exchangers

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 102004023031 A1 [0005]
• DE 3019714 A1 [0005]
• DE 2622722 [0005]
• WO 2011/138171 A2 [0005]
• JP 59198883 A [0005]
• JP60040657A [0005]
• DE 102009031557 A1 [0006]

Claims (15)

Apparatus for energy recovery from a slab ( 200 ), with: at least one with the slab ( 200 ) contactable heat exchanger ( 100 ), wherein the heat exchanger at least one cooling channel ( 110 ), which is flowed through by a heat transfer medium or a cooling medium; characterized in that the heat exchanger is formed eleastisch. Apparatus according to claim 1, characterized in that the heat exchanger in its planar extension of a plurality of preferably coupled together surface elements ( 120-1 . 120-2 . 120-3 ) is formed, and at least some of the surface elements pressing elements ( 130-1 . 130-2 . 130-3 ) are assigned, for pressing the surface elements against the surface of the slab. Apparatus according to claim 2, characterized in that the pressing elements are in the form of field elements or hydraulic cylinders. Apparatus according to claim 2 or 3, characterized in that a first control ( 140 ) is present for driving the pressing elements so that the surface elements can be adjusted with a predetermined pressure against the surface of the slab. Apparatus according to claim 1, characterized in that the heat exchanger ( 100 ) is formed in the form of a temperature-stable, heat-conducting and elastic pad. Apparatus according to claim 5, characterized in that the pad is filled with a filling medium; and a second controller ( 150 ) is provided for adjusting the filling of the pad with the filling medium such that the pad is pressed with a predetermined pressure against the surface of the slab. Device according to claim 1, characterized in that the device comprises two heat exchangers, wherein a first heat exchanger is formed according to one of claims 2, 3 or 4; and a second heat exchanger is formed according to one of claims 5 or 6. Device according to one of the preceding claims with a slab ( 200 ), characterized in that the at least one elastic heat exchanger ( 100 ) is arranged in at least two-dimensional surface contact with at least one of the broad sides of the slab. Apparatus according to claim 8, characterized in that when the heat exchanger from the plurality of surface elements ( 120-1 . 120-2 . 120-3 ), the controller ( 140 ) is designed to control only those pressing elements whose associated surface elements of the surface of the slab are opposite. Device according to one of claims 8 or 9, characterized in that a first part of the surface of the slab, in particular a first broad side of the slab, is contacted with a heat exchanger according to one of claims 2 to 4, and a second part of the surface of the slab, in particular a second broad side of the slab, is contacted with a heat exchanger according to one of claims 5 or 6. Apparatus according to claim any one of claims 8 to 10, characterized in that the non-covered by the heat exchanger sides of the slab, in particular their narrow sides, are thermally insulated. Device according to one of claims 8 to 11, characterized in that the heat transfer coefficient in contacting the heat exchanger with the surface of the slab is at least 1000 W / m ² K. Method for operating the device according to one of claims 1 to 12 for cooling the slab, characterized by the following steps: Contacting the still-warm slab with the at least one elastic heat exchanger; as long as the temperature TB of the slab is still above a predetermined threshold temperature TBS: flow through the heat exchanger with a heat transfer medium, wherein the heat transfer medium due to the heat emitted from the slab from a first inlet temperature TE1 to a first outlet temperature TA1 heats up with TB> TA1> TBS; and after the temperature TB of the slab has fallen below the predefined threshold temperature TBS: flow through the heat exchanger with a cooling medium, wherein the cooling medium heats up from a second inlet temperature TE2 to a second outlet temperature TA2 due to the residual heat of the slab with: TE2 <TE1 and TA2 <TA1. A method according to claim 13, characterized in that it is in the heat transfer medium and the cooling medium material in each case the same media, and the heat transfer medium for its use as a cooling medium is cooled by an example external cooling source to realize the smaller inlet temperature TE2 <TE1. A method according to claim 13 or 14, characterized in that the heat transfer medium with the outlet temperature TA1 after flowing through the heat exchanger only as long as an energy recovery plant for power generation, for example, an ORC or Kalina plant is supplied as the temperature TB of the slab greater than that Threshold temperature TBS is.

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