A heat exchange system and method for a continuous casting mold and a converter furnace

Abstract

This invention discloses a heat exchange system between a continuous casting crystallizer and a converter boiler, comprising a continuous casting crystallizer, a steam drum, a converter hood, and a steam recovery system. The steam drum includes a riser pipe, a downcomer pipe, a first water inlet pipe, and a first steam pipe. The return water inlet of the continuous casting crystallizer is connected to the first water inlet pipe. The converter hood includes a second water inlet pipe and a second steam pipe. The second water inlet pipe is connected to the downcomer pipe, and the second steam pipe is connected to the riser pipe. The first steam pipe is connected to the steam recovery system. This invention discharges the high-temperature cooling water generated by the continuous casting crystallizer into the steam drum of the converter waste heat boiler, reducing the steam consumption for heating the water in the steam drum and improving the efficiency of heat recovery and utilization in the converter waste heat boiler. After the high-temperature steam has its heat recovered by the steam recovery system, it is recondensed into room-temperature water and then returned to the continuous casting crystallizer to participate in the next round of water circulation. This saves water resources and eliminates the need for a cooling tower to cool the high-temperature cooling water output by the continuous casting crystallizer.

Description

Technical Field

[0001] This invention relates to the field of metallurgical continuous casting production line technology, specifically to a heat exchange system and method between a continuous casting crystallizer and a converter boiler. Background Technology

[0002] Converter steelmaking is one of the main methods of smelting. During oxygen blowing smelting, the converter generates a large amount of waste heat. The temperature range of the converter flue gas is between 1400℃ and 1600℃. Therefore, the existing technology uses the method of vaporization cooling to recover the heat of the converter flue gas using a converter hood. The high-temperature steam-water mixture formed by vaporization inside the converter hood is then sent to a waste heat boiler for recycling.

[0003] To ensure the effectiveness of vaporization cooling, water heated to boiling needs to be supplied from the waste heat boiler to the converter hood. This results in the waste heat boiler consuming a large amount of recovered steam to heat the replenished ambient temperature cooling water, greatly reducing the efficiency of the waste heat boiler in heat recovery and utilization.

[0004] Continuous casting is an intermediate link between steelmaking and rolling, an indispensable part of the metallurgical process, and an important component of steel plants. The continuous casting crystallizer, as a forced water-cooled bottomless ingot mold, is where the molten steel initially solidifies, and its performance plays a very important role in the production capacity of the continuous casting machine and the quality of the cast billet.

[0005] To ensure the cooling effect of the continuous casting mold, the existing continuous casting mold is equipped with a complete water circulation system. After passing through the continuous casting mold, the cooling water is fully cooled by the cooling tower in the water circulation system and then sent back to the continuous casting mold for recycling. Since the temperature of the high-temperature cooling water output from the continuous casting mold often does not exceed 70°C, the heat of the high-temperature cooling water is difficult to recover and utilize. Summary of the Invention

[0006] The purpose of this invention is to address the problems existing in the prior art by providing a heat exchange system and method for continuous casting crystallizers and converter boilers.

[0007] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0008] A heat exchange system between a continuous casting crystallizer and a converter boiler includes a continuous casting crystallizer, a steam drum, a converter hood, and a steam recovery system. The steam drum includes a riser pipe, a downcomer pipe, a first water inlet pipe, and a first steam pipe. The return water inlet of the continuous casting crystallizer is connected to the first water inlet pipe. The converter hood includes a second water inlet pipe and a second steam pipe. The second water inlet pipe is connected to the downcomer pipe, the second steam pipe is connected to the riser pipe, and the first steam pipe is connected to the steam recovery system.

[0009] This invention discharges the high-temperature cooling water generated by the continuous casting crystallizer into the steam drum of the converter waste heat boiler, thereby reducing the steam consumption of the steam drum heating water, improving the efficiency of heat recovery and utilization of the converter waste heat boiler, and avoiding the waste of heat from the high-temperature cooling water output by the continuous casting crystallizer.

[0010] In this invention, the high-temperature steam, after having its heat recovered by the steam recovery system, is recondensed into room-temperature water and then returned to the continuous casting crystallizer to participate in the next round of water circulation. This saves water resources and eliminates the need for a cooling tower to cool the high-temperature cooling water output from the continuous casting crystallizer.

[0011] Preferably, the steam drum is equipped with a steam-water separator, the riser pipe is connected to the steam-water separator, the first steam pipe is located above the steam-water separator, and the first water inlet pipe and the downcomer pipe are located below the steam-water separator.

[0012] The riser pipe delivers the high-temperature steam-water mixture into the steam-water separator. The mixture moves downwards in a centrifugal, inclined motion within the separator. The entrained water is separated due to the reduced velocity. The separated liquid flows through the steam-water separator's drain valve and is discharged. Dry, clean, high-temperature steam exits from the steam-water separator outlet. The separated boiling water continues to flow downwards and eventually exits through the downcomer pipe, while the high-temperature steam diffuses upwards and exits through the first steam pipe above.

[0013] Preferably, the inlet of the continuous casting crystallizer is connected to a transfer storage tank, the transfer storage tank is connected to a first pump, and the first pump is connected to a water treatment system.

[0014] Preferably, a transfer sedimentation tank and a second water pump are provided between the return water inlet of the continuous casting crystallizer and the first water inlet pipe. The return water inlet of the continuous casting crystallizer is connected to the transfer sedimentation tank, the second water pump and the first water inlet pipe in sequence through pipelines.

[0015] The intermediate sedimentation tank performs sedimentation treatment on the high-temperature cooling water discharged from the continuous casting crystallizer to reduce impurities entering the steam drum.

[0016] Preferably, the steam recovery system includes a steam turbine generator set, the first steam pipe is connected to the steam turbine generator set, and the condenser of the steam turbine generator set is connected to the water treatment system.

[0017] After the high-temperature steam is used for steam power generation, it is condensed back into room temperature water by the condenser, and the condensed room temperature water is sent to the water treatment system for treatment.

[0018] Preferably, the intermediate water storage tank is also provided with a water inlet, which is connected to the water supply network through a pipe.

[0019] Preferably, the water treatment system includes a deaerator and a third water pump. The deaerator includes a third inlet pipe and an outlet pipe. The third inlet pipe is connected to the condenser through the third water pump, and the outlet pipe is connected to the first water pump.

[0020] The deaerator is used to remove dissolved oxygen from the water and control oxygen corrosion in pipelines, steam drums, or continuous casting molds.

[0021] Preferably, the converter fume hood includes a movable fume hood and a fixed fume hood, and the second water inlet pipe and the second steam pipe are both installed on the movable fume hood.

[0022] Preferably, the outlet pipe is equipped with a filter, a flow meter, and a pressure regulating valve.

[0023] Preferably, a method for heat exchange between a continuous casting crystallizer and a converter boiler includes the following steps:

[0024] Cooling water is sent into the continuous casting crystallizer, and the cooling water is heated to high temperature after heat exchange with the molten steel passing through the continuous casting crystallizer.

[0025] The high-temperature cooling water in the continuous casting crystallizer is discharged into the steam drum through the first water inlet pipe. After heat exchange with the steam-water mixture in the steam drum, the high-temperature cooling water is heated into boiling water.

[0026] The boiling water in the steam drum is discharged into the converter hood through the downcomer. The boiling water evaporates after exchanging heat with the high-temperature flue gas passing through the converter hood to form a steam-water mixture.

[0027] The steam-water mixture inside the converter hood is discharged into the steam drum through the second steam pipe and the riser pipe;

[0028] The steam-water mixture is separated into boiling water and high-temperature steam through the steam drum. The boiling water is discharged into the converter hood through the downcomer, and the high-temperature steam is discharged into the steam recovery system through the first steam pipe.

[0029] During this process, since the cooling water fed into the continuous casting mold is either freshly replenished room temperature water or room temperature water cooled by the condenser, its temperature is easier to control. Even when the ambient temperature is high, the temperature of the cooling water fed into the continuous casting mold can be kept from being too high, which would affect the cooling effect of the continuous casting mold.

[0030] Compared with the prior art, the beneficial effects of the present invention are:

[0031] (1) The present invention discharges the high-temperature cooling water generated by the continuous casting crystallizer into the steam drum of the converter waste heat boiler, which reduces the steam consumption of the steam drum heating water, improves the efficiency of the converter waste heat boiler in heat recovery and utilization, and avoids the waste of heat of the high-temperature cooling water output by the continuous casting crystallizer.

[0032] (2) In this invention, the high-temperature steam is re-condensed into room temperature water after the heat is recovered by the steam recovery system, and then returned to the continuous casting crystallizer to participate in the next round of water circulation process. While saving water resources, there is no need to set up a cooling tower to cool the high-temperature cooling water output by the continuous casting crystallizer. Attached Figure Description

[0033] Figure 1 This is a schematic diagram of the structure of the present invention;

[0034] Figure 2 This is a schematic diagram of the structure of the steam drum in this invention;

[0035] In the diagram: 1. Continuous casting crystallizer; 2. Steam drum; 201. Steam-water separator; 202. Ascend pipe; 203. Downcomer; 204. First steam pipe; 205. First water inlet pipe; 3. Converter hood; 301. Second water inlet pipe; 302. Second steam pipe; 4. Steam recovery system; 5. Deaerator; 501. Third water inlet pipe; 502. Water outlet pipe; 6. Ladle; 7. Molten steel; 8. Transfer reservoir; 801. Water inlet; 9. Transfer sedimentation tank; 10. First water pump; 11. Second water pump; 12. Third water pump. Detailed Implementation

[0036] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are merely some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0037] In the description of this invention, it should be noted that the terms "middle", "upper", "lower", "left", "right", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0038] like Figures 1-2 As shown, the specific scheme of the embodiment is as follows: a heat exchange system between a continuous casting crystallizer and a converter boiler, including a continuous casting crystallizer 1, a steam drum 2, a converter fume hood 3 and a steam recovery system 4.

[0039] The continuous casting crystallizer 1 is a container used to cool the molten steel 7 flowing out of the ladle 6 and to form a billet shell. The converter hood 3 is used to cool the high-temperature flue gas discharged from the converter. The steam recovery system 4 adopts a steam turbine generator set.

[0040] The inlet of the continuous casting crystallizer 1 is connected to the intermediate water storage tank 8, the intermediate water storage tank 8 is connected to the first water pump 10, the first water pump 10 is connected to the water treatment system, and the intermediate water storage tank 8 is also equipped with a water supply inlet 801, which is connected to the water supply network through a pipeline.

[0041] The steam drum 2 includes a riser pipe 202, a downcomer pipe 203, a first water inlet pipe 205, and a first steam pipe 204. The return water inlet of the continuous casting crystallizer 1 is connected to the first water inlet pipe 205. The converter hood 3 includes a second water inlet pipe 301 and a second steam pipe 302. The second water inlet pipe 301 is connected to the downcomer pipe 203, the second steam pipe 302 is connected to the riser pipe 202, and the first steam pipe 204 is connected to the steam turbine generator set. The condenser of the steam turbine generator set is connected to the water treatment system.

[0042] A transfer sedimentation tank 9 and a second water pump 11 are provided between the return water inlet of the continuous casting crystallizer 1 and the first water inlet pipe 205. The return water inlet of the continuous casting crystallizer 1 is connected to the transfer sedimentation tank 9, the second water pump 11 and the first water inlet pipe 205 in sequence through pipelines.

[0043] The water treatment system includes a deaerator 5 and a third water pump 12. The deaerator 5 includes a third inlet pipe 501 and an outlet pipe 502. The third inlet pipe 501 is connected to the condenser through the third water pump 12, and the outlet pipe 502 is connected to the first water pump 10. The outlet pipe 502 is equipped with a filter, a flow meter and a pressure regulating valve.

[0044] Deaerator 5 can be a sponge iron deaerator 5, which uses activated sponge iron to remove dissolved oxygen in water. The main component of sponge iron is iron. Its loose and porous internal structure provides a specific surface area that is 50,000 to 100,000 times that of ordinary iron filings. When water containing oxygen enters the sponge iron deaerator 5 and passes through the sponge iron filter media layer, the dissolved oxygen in the water can undergo a rapid oxidation reaction with the iron, thereby removing the oxygen from the water.

[0045] Since the sponge iron deaerator 5 operates at room temperature, no additional heat source is required. The water temperature of the condensate after treatment by the sponge iron deaerator 5 can meet the cooling water temperature requirements of the continuous casting mold 1. The water after treatment by the sponge iron deaerator 5 can be directly sent back to the transfer storage tank 8 to participate in the cooling of the continuous casting mold 1.

[0046] The steam drum 2 is equipped with a steam-water separator 201. The riser pipe 202 is connected to the steam-water separator 201. The first steam pipe 204 is located above the steam-water separator 201, and the first water inlet pipe 205 and the downcomer pipe 203 are located below the steam-water separator 201.

[0047] The riser pipe 202 sends the high-temperature steam-water mixture into the steam-water separator 201. The steam-water mixture moves downward in a centrifugal, inclined motion in the steam-water separator 201. The entrained water is separated due to the reduced speed. The separated liquid flows through the steam trap of the steam-water separator 201 and is discharged. The dry and clean high-temperature steam is discharged from the outlet of the steam-water separator 201. The separated boiling water continues to flow downward and eventually flows out from the downcomer pipe 203. The high-temperature steam diffuses upward and flows out from the first steam pipe 204 above.

[0048] The first water inlet pipe 205 sends the high-temperature cooling water discharged from the continuous casting crystallizer 1 into the steam drum 2 to maintain the water level in the steam drum 2.

[0049] The converter fume hood 3 includes a movable fume hood and a fixed fume hood. The second water inlet pipe 301 and the second steam pipe 302 are both installed on the movable fume hood.

[0050] A method for heat exchange between a continuous casting crystallizer and a converter boiler includes the following steps:

[0051] (1) Cooling water is sent to the intermediate storage tank 8 through the water supply network, and then sent to the continuous casting crystallizer 1 through the intermediate storage tank 8. The cooling water is heated to high temperature after heat exchange with the molten steel 7 that has passed through the continuous casting crystallizer 1.

[0052] (2) The high-temperature cooling water in the continuous casting crystallizer 1 flows into the transfer sedimentation tank 9, and the calcium and iron contained in the water are treated by natural sedimentation or by adding a softener, so as to reduce the impact on the water quality in the steam drum 2 and avoid the steam drum 2 being rapidly corroded.

[0053] (3) The high-temperature cooling water treated by the transfer sedimentation tank 9 is discharged into the steam drum 2 through the first water inlet pipe 205. After heat exchange with the steam-water mixture in the steam drum 2, the high-temperature cooling water is heated into boiling water.

[0054] (4) The boiling water in the steam drum 2 is discharged into the converter hood 3 through the downcomer 203 and the second water inlet pipe 301. The boiling water evaporates after heat exchange with the high-temperature flue gas passing through the converter hood 3 to form a steam-water mixture.

[0055] (5) The steam-water mixture in the converter hood 3 is discharged into the steam drum 2 through the second steam pipe 302 and the riser pipe 202;

[0056] (6) The steam-water mixture is separated into boiling water and high-temperature steam through the steam drum 2. The boiling water is discharged into the converter hood 3 through the downcomer 203, and the high-temperature steam is discharged into the steam turbine generator set of the steam recovery system 4 through the first steam pipe 204.

[0057] (7) The steam turbine generator set uses high-temperature steam to generate electricity, and the condenser serves as the cold source for the steam turbine generator to re-condense the high-temperature steam into room temperature water;

[0058] (8) The condenser discharges ambient temperature water into the deaerator 5 for deoxygenation treatment. The treated ambient temperature water is sent back to the intermediate storage tank 8 to participate in the next round of water circulation.

[0059] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A heat exchange system between a continuous casting crystallizer and a converter boiler, characterized in that, The system includes a continuous casting crystallizer, a steam drum, a converter hood, and a steam recovery system. The steam drum includes a riser pipe, a downcomer pipe, a first water inlet pipe, and a first steam pipe. The return water inlet of the continuous casting crystallizer is connected to the first water inlet pipe. The converter hood includes a second water inlet pipe and a second steam pipe. The second water inlet pipe is connected to the downcomer pipe, the second steam pipe is connected to the riser pipe, and the first steam pipe is connected to the steam recovery system.

2. The heat exchange system between a continuous casting crystallizer and a converter boiler according to claim 1, characterized in that, The steam drum is equipped with a steam-water separator. The riser pipe is connected to the steam-water separator. The first steam pipe is located above the steam-water separator, and the first water inlet pipe and the downcomer pipe are located below the steam-water separator.

3. The heat exchange system between a continuous casting crystallizer and a converter boiler according to claim 1, characterized in that, The inlet of the continuous casting crystallizer is connected to a transfer storage tank, the transfer storage tank is connected to a first pump, and the first pump is connected to a water treatment system.

4. The heat exchange system between a continuous casting crystallizer and a converter boiler according to claim 1, characterized in that, A transfer sedimentation tank and a second water pump are provided between the return water inlet of the continuous casting crystallizer and the first water inlet pipe. The return water inlet of the continuous casting crystallizer is connected to the transfer sedimentation tank, the second water pump and the first water inlet pipe in sequence through pipelines.

5. The heat exchange system between a continuous casting crystallizer and a converter boiler according to claim 3, characterized in that, The steam recovery system includes a steam turbine generator set, the first steam pipe is connected to the steam turbine generator set, and the condenser of the steam turbine generator set is connected to the water treatment system.

6. The heat exchange system between a continuous casting crystallizer and a converter boiler according to claim 3, characterized in that, The intermediate water storage tank is also equipped with a water supply inlet, which is connected to the water supply network via a pipe.

7. The heat exchange system between a continuous casting crystallizer and a converter boiler according to claim 5, characterized in that, The water treatment system includes a deaerator and a third water pump. The deaerator includes a third inlet pipe and an outlet pipe. The third inlet pipe is connected to the condenser through the third water pump, and the outlet pipe is connected to the first water pump.

8. The heat exchange system between a continuous casting crystallizer and a converter boiler according to claim 1, characterized in that, The converter fume hood includes a movable fume hood and a fixed fume hood, and the second water inlet pipe and the second steam pipe are both installed on the movable fume hood.

9. A heat exchange system between a continuous casting crystallizer and a converter boiler according to claim 7, characterized in that, The outlet pipe is equipped with a filter, a flow meter, and a pressure regulating valve.

10. A method for heat exchange between a continuous casting crystallizer and a converter boiler, characterized in that, Using a heat exchange system between a continuous casting crystallizer and a converter boiler as described in any one of claims 1 to 9, the method includes the following steps: Cooling water is sent into the continuous casting crystallizer, and the cooling water is heated to high temperature after heat exchange with the molten steel passing through the continuous casting crystallizer. The high-temperature cooling water in the continuous casting crystallizer is discharged into the steam drum through the first water inlet pipe. After heat exchange with the steam-water mixture in the steam drum, the high-temperature cooling water is heated into boiling water. The boiling water in the steam drum is discharged into the converter hood through the downcomer. The boiling water evaporates after exchanging heat with the high-temperature flue gas passing through the converter hood to form a steam-water mixture. The steam-water mixture inside the converter hood is discharged into the steam drum through the second steam pipe and the riser pipe; The steam-water mixture is separated into boiling water and high-temperature steam through the steam drum. The boiling water is discharged into the converter hood through the downcomer, and the high-temperature steam is discharged into the steam recovery system through the first steam pipe.

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