Method and strand guide device for operating a cooling chamber

Abstract

The disclosure relates to a method for operating a cooling chamber in a strand guide device and the strand guide device 10 as such. The strand guide device serves to deflect a freshly cast strand, typically made of metal, into the horizontal. During the deflection, the cast strand passes through a cooling chamber 1 inside the strand guide device 2, in which it is sprayed with a coolant 33, with the formation of steam 5. The steam forms at least a steam-air mixture 5 with sucked-in secondary air, which is sucked out of the cooling chamber by a suction device 20. In particular, in order to reduce the pollutant content of the sucked-in and sucked-off steam-air mixture 5 and its emission into the environment, the present invention provides for pollutants, primarily dust, located in the steam-air mixture 5 by a separator 6, 6 to deplete.

Claims

1. A method for operating a continuous caster (100), comprising: deflecting a cast strand (13) after it exits a mold (40) of the continuous caster (100) into a horizontal orientation in a strand guide device (10) arranged downstream of the mold; cooling the cast strand (13) as it passes through a cooling chamber (1) inside the strand guide device (10) by spraying a coolant (33) onto the cast strand (13) causing steam (5) to form inside the cooling chamber (1), wherein the steam (5) forms, at least together with sucked-in secondary air, a steam-air mixture (5) which is at least partially saturated with the coolant (33); and extracting the steam-air mixture (5) from the cooling chamber (1) using a suction device (20) which comprises a suction fan (8), a suction opening (3) opening into the cooling chamber (1), and a suction duct (7) connecting the suction opening (3) and the suction fan (8); and depleting the steam-air mixture (5) by a separator (6).

2. The method according to claim 1, wherein depleting the steam-air mixture (5) within the separator (6) takes place by condensation and/or droplet separation in connection with air rectification.

3. The method according to claim 1, wherein depleting the steam-air mixture (5) takes place by the separator (6) arranged inside the cooling chamber (1) in front of the suction opening (3) of the suction device (20), and wherein the method further comprises draining condensed steam-air mixture (5) from the separator (6) into a waste water channel (24) inside the cooling chamber (1).

4. The method according to claim 1, wherein depleting the steam-air mixture (5) takes place alternatively or additionally by the separator (6) arranged in the suction duct (7) of the suction device (20) and/or a further separator (6).

5. The method according to claim 1, wherein depleting the steam-air mixture (5) also takes place before, on, or in the suction fan (8) of the suction device (20) by attachments and/or built-in components (16) by which a medium is introduced into the extracted steam-air mixture (5).

6. The method according to claim 1, wherein preconditioned steam-air mixture (5) after passing the suction fan to an extent of a first portion is returned to the cooling chamber (1); and/or to an extent of a second portion is supplied to a conditioning device (Z) to there be further conditioned.

7. The method according to claim 1, wherein the steam-air mixture (5) has a higher relative humidity than air supplied to the cooling chamber.

8. The method according to claim 1, wherein additional air (14) is blown into the cooling chamber (1) by a pressure fan (4), the pressure fan (4) being installed opposite the suction opening (3) of the suction device (20).

9. The method according to claim 8, wherein the additional air is outside air (70) sucked in from outside a hall (200), interior air (80) sucked in from the hall (200) and/or steam-air mixture (5) extracted out of the cooling chamber (1, 1) after it has been preconditioned; and wherein the additional air (14) is generated by extracted and preconditioned steam-air mixture (5) being conditioned by a conditioning device (Z), and/or by the outside air (70) or the interior air (80) being conditioned by an additional conditioning device (60) before being blown into the cooling chamber (1), the conditioning comprising at least one of cooling and/or heating of the additional air (14), increasing humidity of the additional air (14) by partial air recirculation or media injection, cleaning the additional air (14); and depleting pollutants of the additional air (14) by admixture of adsorbents.

10. The method according to claim 9, wherein the preconditioned steam-air mixture (5) is cooled, dehumidified and/or cleaned in the conditioning device (Z).

11. A strand guide device (10), comprising: strand guide rollers (2) for guiding a cast strand (13) that has been cast by a mold (40) arranged upstream of the strand guiding device (10); a cooling device (30) with a cooling chamber (1) for cooling the cast strand (13) as it runs through the cooling chamber (1) by spraying a coolant (33) onto the cast strand (13) thereby forming a steam-air mixture (5) within the cooling chamber (1), wherein the steam-air mixture (5) is at least partially saturated with the coolant (33); a suction device (20), which includes a suction fan (8), a suction opening (3) in the cooling chamber (1), and a suction duct (7) connecting the suction opening (3) to the suction fan (8), for extracting the steam-air mixture (5) from the cooling chamber (1); and a separator (6, 6) for depleting pollutants (33) from the extracted steam-air mixture (5).

12. The strand guide device (10) according to claim 11, wherein the separator (6) is arranged in front of the suction opening (3) of the suction device (20) in the cooling chamber (1, 1) for condensing the coolant (33) within the cooling chamber (1, 1); and wherein the cooling chamber (1) has a waste water channel (24) for draining off the condensate (22).

13. The strand guide device (10) according to claim 11, wherein the separator (6) is arranged in the suction duct (7) of the suction device (20).

14. The strand guide device (10) according to claim 12, further comprising a further separator (6) arranged in the suction duct (7) of the suction device (20).

15. The strand guide device according to claim 11, further comprising attachments and/or built-in components (16) arranged in front of, on, in or behind the suction fan (8) for introducing a separating agent or absorbents into the steam-air mixture (5) to deplete it of dirt and/or pollutants.

16. The strand guide device (10) according to claim 11, further comprising a pressure fan (4) for blowing additional air (14) into the cooling chamber (1), the pressure fan (4) being arranged opposite the suction opening (3) of the suction device (20) in the cooling chamber (1).

17. The strand guide device (10) according to claim 11, further comprising a first partial air return line (11) for returning at least a first portion of preconditioned steam-air mixture (5) from an extended suction duct (9) into the cooling chamber (1).

18. The strand guide device (10) according to claim 17, further comprising a first distribution device (Z7_1), in form of a first distribution flap, in an extended exhaust air duct (9) at an outlet of the suction fan (8), for variable adjustment of the first portion of depleted or preconditioned steam-air mixture (5), which is routed back into the cooling chamber (1) preconditioned via the first partial air return line (11), and a second portion of the depleted steam-air mixture which is routed past the first partial air return line (11).

19. The strand guide device (10) according to claim 18, further comprising a conditioning device (Z) downstream of the first distribution device (Z7_1) for receiving and conditioning a second portion of extracted and preconditioned steam-air mixture, wherein the conditioning device (Z) includes at least one of a cooler (Z2) for cooling the second portion of the extracted steam-air mixture; a dehumidifier (Z3) for dehumidifying the cooled steam-air mixture by condensing; a filter (Z4) for cleaning the steam-air mixture; or a heat exchanger (Z1) for reheating the dehumidified and/or cooled steam-air mixture by extracting heat from the supplied second portion of the extracted steam-air mixture at an inlet of the conditioning device (Z) and for outputting a conditioned steam air mixture (5).

20. The strand guide device (10) according to claim 19, further comprising a second distribution device (Z7_2) downstream of the conditioning device (Z) for variably adjusting a first and a second portion of conditioned steam-air mixture (5) at the outlet of the conditioning device (Z); a second partial air return line (17) for directing the first portion of the conditioned steam-air mixture (5) back into the cooling chamber (1); and an outlet line (18) for conducting the second portion of the conditioned steam-air mixture (5) into a hall (200) surrounding the strand guide device (100) or outside the hall (200) surrounding the strand guide device.

21. The strand guide device according to claim 20, further comprising a damper (Z6) connected downstream of the second distribution device (Z7_2) for damping a flow noise of the second portion of the conditioned steam-air mixture in the outlet line (18).

22. The strand guide device according to claim 20, further comprising a fourth distribution device (Z7_4) for generating an air mixture at its outlet from received hall air (80) and outside air (70) in a predetermined mixing ratio; an additional conditioning device (60) for conditioning the air mixture to reduce its dirt and pollutant content; and a third distribution device (Z7_3) arranged in the second partial air return line (17) for mixing the first portion of the conditioned steam-air mixture (5) with the conditioned air mixture in a predetermined mixing ratio to generate the additional air (14) supplied into the cooling chamber (1, 1).

23. The strand guide device according to claim 11, wherein the cooling device (30) has a first and a second cooling chamber (1, 1) which are arranged one behind the other in a casting direction (G) within the strand guide device (10); wherein the first and the second cooling chamber (1, 1) are connected to one another via an air duct (50); and wherein an air washer (52) is arranged in the air duct (50) for filtering and/or cleaning a steam-air mixture (5) flowing in the air duct (50) counter to the casting direction (G) from the second cooling chamber (1) arranged further downstream in the casting direction of the first cooling chamber (1).

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0035] FIG. 1 shows a cooling chamber with associated suction device according to a first to sixth exemplary embodiment.

[0036] FIG. 2 shows different versions of a separator.

[0037] FIG. 3 shows the cooling chamber according to a seventh embodiment with a conditioning device.

[0038] FIG. 4 shows a strand guide device with two cooling chambers arranged one behind the other according to an eighth exemplary embodiment.

[0039] FIG. 5 shows a strand guide device according to the prior art.

[0040] FIG. 6 shows a cooling chamber with associated suction device according to the prior art.

DETAILED DESCRIPTION

[0041] The invention is described in detail below with reference to FIGS. 1 to 4 in the form of exemplary embodiments. The same technical elements are denoted by the same reference symbols in all figures.

[0042] FIG. 1 shows a cross section through a cooling chamber 1 of a strand guide device 10 of a continuous caster. FIG. 1 shows in particular a segment 12 of the strand guide device 10 with strand guide rollers 2 in cross section, between which the cast strand 13 is guided. The cooling chamber 1 forms a housing for the strand guide device 1, in particular the segments 12. It has undesired openings through which secondary air 15 in the form of ambient air or indoor air is inevitably sucked in as well. FIG. 1 shows the cooling chamber 1 with a plurality of exemplary embodiments, as will be described further below.

[0043] On its way through the strand guide device, more precisely through its segments 12, the cast strand 13 is cooled in the cooling chamber 1 by spraying with a coolant 33. The steam 5 produced by the evaporation of the coolant together with the inevitably sucked in secondary air 15 form a steam-air mixture 5. This is at least partially saturated with the coolant 33.

[0044] It can also be seen in FIG. 1 that the cooling chamber 1 is assigned a suction device 20 for sucking off the steam-air mixture 5 from the cooling chamber 1. The suction device 20 comprises a suction fan 8 and a suction duct 7 which connects a suction opening 3 in the cooling chamber 1 to the suction fan 8. The continuation of the suction duct 7 downstream of the suction fan 8 is denoted by the reference number 9. The continuation of the suction duct can direct the suctioned-off steam-air mixture 5 to a chimney 19. However, this variant is not favored.

[0045] In contrast to the prior art, at least one preferably multi-layer separator 6, 6 is provided, as shown in FIG. 2, left and right illustration, for example with 2 and 3 layers, also called packages. The separator 6 and possibly a further separator 6 are designed to implement at least one of the following functions and to treat the steam-air mixture 5 accordingly:

[0046] Condensation: Condensation describes the functionality with which the aerosols, fine dust aerosols and water vapor in the exhaust air, i.e., in the extracted steam-air mixture 5, are separated from the steam-air mixture 5 by active cooling (with cooling water). This can be referred to as physical separation. As part of the condensation function, the steam-air mixture is preferably cooled adiabatically and at the same time moisture is removed from it. This is achieved in that the moisture is condensed out of the sucked-in steam-air mixture 5 by the separator 6,6.

[0047] Droplet separation: This function of the separator is implemented in that the sucked-in steam-air mixture 5 is deflected at a minimum speed. Due to their inertia, any heavy droplets present in the mixture 5 cannot follow the deflection of the air. Instead, they take a trajectory that deviates from the deflection. This effect can be utilized in order to enable a first separation of the coarse droplets with dirt and/or pollutants deposited on them from the mixture 5. The function can be described as mechanical separation.

[0048] Air rectification: The rectification of the sucked-in steam-air mixture 5 within the separator can be optimally adjusted by the specific arrangement of the separator packs according to FIG. 2 and their distance from one another. Uniform flow velocities are produced over the entire suction area without significantly changing the penetration depth. In this way, the effective suction area can even be expanded beyond the extent of the actual opening of the extraction point. Tests have shown that the suction area can be expanded by up to 30%.

[0049] Self-cleaning: The functionality of the self-cleaning of the separator is implemented in such a way that drops with accumulated dirt and/or pollutant particles are safely discharged with the draining condensate water on the smooth pipes of the separator. Due to the permanently moist pipes, the risk of caking is almost completely eliminated.

[0050] Individual or all of the functionalities mentioned can take place in sequence or simultaneously. If the separator 6 and/or the further separator 6 is designed to implement two or more of the functions mentioned, they are also referred to as multi-function separators.

[0051] As shown in FIG. 1, according to a first exemplary embodiment, the separator 6 is advantageously arranged in front of the suction opening 3 of the suction device 20 in the cooling chamber. This is advantageous because the condensate 22 emerging in the separator 6, in particular the condensed coolant, can then be discharged through a waste water channel 24 or a sinter channel within the cooling chamber 1. Alternatively, according to a second exemplary embodiment, the separator can also be arranged in the direction of flow of the steam-air mixture 5 between the suction opening 3 and the suction fan 8 in the suction duct 7 or also in the exhaust air duct 9 that continues behind the suction fan in the direction of flow.

[0052] If, according to a third exemplary embodiment, not only a single separator 6 but also a further separator 6 is provided, this can (likewise) be arranged in the suction duct 7. In cases where the separator 6 and/or the further separator 6 are arranged in the suction duct 7, there must be a possibility in the suction channel 7 for collecting and discharging the condensate 22 generated there.

[0053] The cooling water required for the operation of the separator can be taken from the secondary cooling water of the strand guide device 10 and does not have to be specially conditioned. In addition, the water, which is separated via the separator 6, 6 is returned to the cooling circuit and is not fed to the environment via the chimney 19 as a steam-air mixture. This leads to an additional saving of water.

[0054] Optionally, the depletion of the steam-air mixture 5except by the separator 6, 6can, according to a fourth embodiment, additionally be effected by means of attachments and built-in components 16, such as spray nozzles, which are arranged in front of, in, on orin the direction of flowbehind the suction fan 8. They offer an additional possibility of reducing or preconditioning the pollutant content of the steam-air mixture 5 before it is passed on into the exhaust air chimney 19, into a first partial air return line 11 or into a conditioning device Z, see FIG. 3.

[0055] According to a fifth exemplary embodiment, additional air can optionally be blown into the cooling chamber 1 by a pressure fan 4. The pressure fan 4 is preferably arranged in the cooling chamber 1 opposite the suction opening 3 of the suction device 20, as shown in FIG. 1. The additionally supplied air 14 mixes in the cooling chamber 1 with the steam-air mixture 5 already present there.

[0056] The additional air 14 can be generated by conditioning the steam-air mixture 5 sucked out of the cooling chamber 1 with the conditioning device Z, by conditioning indoor air 80 sucked out of the hall 200 with a further conditioning device 60 and/or by preferably conditioning outside air 70, also with the conditioning device 60, the outside air being sucked in from outside the hall 200.

[0057] The type and scope of the conditioning depend on the type and quality of the air drawn in. The proportions of the three possible components mentioned in the additional air 14 are adjusted via a third distribution device Z7_3 and/or a fourth distribution device Z7_4, each designed in the form of a distribution flap, for example. By the distribution device Z7_4, for example, the quantitative proportions of the indoor air 80 and the intake outside air 70 in the additional air 14 can be variably preset. These proportions are depleted to the extent necessary by the further conditioning device 60. With the help of the distribution device Z7_3, for example, the proportions of the conditioned steam-air mixture 5 and the air at the outlet of the further conditioning device Z7_4 in the additional air 14 can be variably adjusted. The individual proportions of the three possible components in the total amount of additional air 14 supplied is between 0% and 100% each, and in sum always 100%. The arrangement of the distribution devices Z7_3 and Z7_4 and the further conditioning device 60 shown in FIG. 1 are merely exemplary. Other interconnections of these devices or use of fewer than all of the devices are also conceivable, depending on which of the possible components or proportions the additional air 14 is supposed to contain. The distribution devices Z7_3 and Z7_4 and the further conditioning device 60 can also be omitted completely if only the conditioned steam-air mixture 5 is to be fed into the cooling chamber 1 as additional air 14 or no additional air 14 is used at all.

[0058] Catch grates can be provided as a system protection in front of or in the separator 6 or in the suction duct 7 in order to protect subsequent system parts in the direction of flow from undesired external influences due to coarse foreign objects that have been sucked in.

[0059] According to a sixth exemplary embodiment, a first distribution device Z7_1, for example in the form of a first distribution flap, is located in the extended exhaust air duct 9, preferably at the outlet of the suction fan 8, before the first partial air return line 11. The first distribution device Z7_1 serves to variably divide the preconditioned steam-air mixture 5 into a first and a second portion. The first portion of the preconditioned steam-air mixture is fed back into the cooling chamber 1 via the first partial air return line 11.

[0060] The second portion of the steam-air mixture is routed past the first partial air return line 11 and is either discharged via the chimney 19 into the area surrounding the strand guide device 100 (not favored) or, according to a seventh exemplary embodiment, supplied to the conditioning device Z via the extended exhaust air duct 9.

[0061] FIG. 3 shows the cooling chamber 1 according to the seventh embodiment. This relates essentially to the treatment of the steam-air mixture 5 which has been sucked out of the cooling chamber 1 andas described abovepreferably already preconditioned.

[0062] In the conditioning device Z, the second portion of the steam-air mixture preferably first runs through a cooler Z2 for the purpose of cooling. As a result of the cooling, the steam-air mixture 5 is further preconditioned for a subsequent removal of (air) moisture. A dehumidifier Z3 is connected downstream of the cooler Z2 for dehumidifying the cooled steam-air mixture by (out) condensing. The dehumidifier is followed by a filter Z4 for cleaning the steam-air mixture and a heat exchanger Z1 for reheating the dehumidified and cooled steam-air mixture, preferably by extracting heat from the supplied second portion of the extracted steam-air mixture at the inlet of the conditioning device Z. As a result, the incoming steam-air mixture is advantageously already pre-cooled before it reaches the cooler Z2. Finally, the conditioning device Z outputs a conditioned steam-air mixture 5. The conditioning device Z does not necessarily have to have all of the components mentioned, such as the cooler Z2, the dehumidifier Z3, the filter Z4 and the heat exchanger Z1. Depending on the configuration, the conditioning device Z can also only contain individual components.

[0063] The steam-air mixture 5 conditioned in this way is routed to a second distribution device Z7_2. This second distribution device, for example in the form of a second distribution flap, is used for variably dividing the conditioned steam-air mixture 5 into a first and a second portion. The first portion is fed back into the cooling chamber 1 via a second partial air return line 17 as the additionally supplied air 14 or a part thereof. Optionally, this takes place with the addition of indoor air 80 or outside air 70, as already described above with reference to FIG. 1 and as indicated by the third distribution device Z7_3 drawn in dashed lines in FIG. 3. The second portion of the conditioned steam-air mixture 5 is conducted via an exit line 18 into the hall 200 surrounding the strand guide device 10 or to the outside of the hall 200.

[0064] A damper Z6 is preferably connected downstream of the second distribution device Z7_2 to dampen the flow noise of the second portion of the conditioned steam-air mixture 5 in the outlet line 18.

[0065] FIG. 4 illustrates an eighth embodiment. Accordingly, in the strand guide device a plurality of cooling chambers 1, 1 are arranged one behind the other, through which the cast strand 13 cast in the mold 40 passes in succession. Two adjacent cooling chambers 1, 1 are each connected to one another via an (exhaust) air duct 50, which extends in the casting direction G, and thus form an overall system that communicates with one another in terms of air flow. Only the first cooling chamber 1, i.e., the cooling chamber immediately downstream of the mold 40, is connected to a lateral suction device 20. In contrast to the prior art, the cooling chambers 1 arranged downstream in the casting direction G no longer each have their own lateral suction device. Instead, the exhaust air, i.e., the steam-air mixture, is also sucked out of the downstream cooling chambers 1 counter to the casting direction G through said air duct 50 into the first, uppermost cooling chamber 1, ultimately effected by the suction device 20 assigned to the first cooling chamber. The extracted exhaust air passes through an air washer 52 within the air ducts 50 before it reaches the first uppermost cooling chamber 1 and is extracted there by the suction device 20. Since the exhaust air from a cooling chamber first passes through the air washer 52, it is pre-cleaned before it reaches the first or uppermost cooling chamber.

[0066] The air washers 52 are operated with water. The water required for this can be taken from the secondary cooling water circuit, with which the cast strand 13 is (secondarily) cooled in the upper cooling chambers. This is possible because, in particular in the cooling chambers arranged further down in the casting direction G, as mentioned, a particularly large cooling capacity is no longer required; the (secondary) cooling water available there can therefore be used for the air washers there to clean the exhaust air.

[0067] The air ducts 50 are quasi assigned to the cooling chambers 1; in this respect, the cleaning of the exhaust air takes place by the air washer 52, so to speak, within the respectively downstream cooling chambers 1. The cooling water used for the operation of the air washer 52 from the secondary cooling water circuit does not have to be specially conditioned beforehand. After it has passed through the air washer 52, it can be returned to the secondary cooling water circuit, and it does not have to be processed separately for this either. This leads to an additional saving of water. Overall, the use of the air washer 52 brings about a significant pre-cleaning, i.e., a reduction in the pollutant content in the exhaust air from the respective cooling chamber.

REFERENCE SIGN LIST

[0068] 1 cooling chamber [0069] 1 cooling chamber [0070] 2 strand guide rollers [0071] 3 suction opening [0072] 4 pressure fan [0073] 5 steam [0074] 5 steam-air mixture [0075] 5 conditioned steam-air mixture [0076] 6 separator [0077] 6 further separator [0078] 7 suction duct [0079] 8 suction fan [0080] 9 extended exhaust air duct (chimney) [0081] 10 strand guide device [0082] 11 first partial air return line [0083] 12 segment of the strand guide device [0084] 13 casting strand [0085] 14 additional air [0086] 15 secondary air [0087] 16 attachments and/or build-in components [0088] 17 first partial air return line [0089] 18 output line [0090] 19 chimney [0091] 20 suction device [0092] 22 condensate [0093] 24 waste water channel [0094] 30 cooling device [0095] 33 coolant [0096] 40 mold [0097] 50 air duct [0098] 52 air washer [0099] 60 additional conditioning device [0100] 70 outside air [0101] 80 indoor air [0102] 100 continuous caster [0103] 200 hall [0104] G casting direction [0105] Z conditioning device [0106] Z1 heat exchanger [0107] Z2 cooler [0108] Z3 dehumidifier [0109] Z4 filter [0110] Z6 damper [0111] Z7_1 exhaust air distribution flap (first distribution device) [0112] Z7_2 return distribution flap (second distribution device) [0113] Z7_3 third distribution device [0114] Z7_4 fourth distribution device