A device and method for preheating both submerged nozzle and casting protection slag

Abstract

The present invention relates to a device and method for preheating an immersed nozzle and casting protective slag together, comprising an outer shell, an inner shell, a spray gun system, an inner shell lifting rod, an air outlet preheating channel, an air inlet preheating channel, an upper cover plate, a fixer and an immersed nozzle, wherein the bottom of the inner shell is closed and arranged in an outer shell with an opening on the top, a gap is left between the inner shell and the side wall of the outer shell, the air inlet preheating channel is arranged in the inner shell, the spray gun system is arranged directly above the air inlet preheating channel, the air outlet preheating channel is connected to the gap between the inner shell and the outer shell and is arranged in the inner shell, the air inlet preheating channel and the air outlet preheating channel are connected with the bottom of the inner shell, the inner shell lifting rod is fixedly arranged on both sides of the inner shell and movably erected on the upper edge of the outer shell, the upper cover plate covers the top of the outer shell, and the upper cover plate is provided with through holes corresponding to the air outlet preheating channel and the air inlet preheating channel; the present invention realizes the simultaneous preheating of the immersed nozzle and the protective slag, improves the preheating efficiency and reduces energy consumption.

Description

Technical Field

[0001] The present invention relates to the technical field of continuous casting, and in particular to a device and method for preheating a submerged nozzle and start-casting protective slag together. Background Art

[0002] In the steelmaking continuous casting production process, the preheating of the submerged nozzle is a key link. In the existing technology, the method of preheating the submerged nozzle with gas is usually adopted. If the nozzle is not preheated enough, it will affect the service life of the nozzle. In severe cases, it will cause the nozzle to break and fail, leading to production safety accidents. If the nozzle is over-preheated, it will cause the refractory material of the nozzle to oxidize and cause decarburization and loosening, resulting in nodules and blockage on the inner wall of the nozzle. Therefore, ensuring the preheating effect of the submerged nozzle is related to the stability of continuous casting production and product quality. In addition, when the continuous casting production starts pouring, if the temperature of the molten steel is low, it is easy to stop or interrupt the pouring. The risk will affect the production rhythm at the least, and may even lead to safety accidents such as steel leakage. Preheating the protective slag for the start of pouring can effectively reduce the risk of stopping or interrupting the pouring due to the rapid temperature drop of the molten steel during the start of pouring operation. The existing offline nozzle preheating method and protective slag preheating method both consume a large amount of coal gas, resulting in energy waste. Therefore, the present invention proposes a device and method for preheating a submerged nozzle and start-cast protective slag together, which improves the nozzle preheating method. While ensuring the preheating effect, the flue gas waste heat is used to synchronously preheat the start-cast protective slag, thereby reducing the energy consumption of the continuous casting production process and ensuring the smooth operation of the continuous casting production. Summary of the Invention

[0003] The present invention provides a device and method for preheating an immersion nozzle and protective slag simultaneously, which realizes the simultaneous preheating of the immersion nozzle and the protective slag, improves the preheating efficiency, and reduces energy consumption. At the same time, the preheating flue gas is used to preheat the protective slag for pouring, which effectively reduces the risk of condensation of molten steel caused by the large amount of heat absorbed by the protective slag during the continuous casting process, thereby improving the stability of continuous casting production and product quality.

[0004] In order to achieve the above object, the present invention adopts the following technical solutions:

[0005] A device for preheating both an immersed nozzle and casting protection slag, comprising an outer shell, an inner shell, a spray gun system, an inner shell lifting rod, an air outlet preheating channel, an air inlet preheating channel, an upper cover plate, a fixer and an immersed nozzle, wherein the bottom of the inner shell is closed and arranged in an outer shell with an upper opening, the inner shell is used to contain and preheat the protection slag, a gap is left between the inner shell and the side wall of the outer shell, the air inlet preheating channel is arranged in the inner shell, the spray gun system is arranged directly above the air inlet preheating channel, and the nozzle of the spray gun system corresponds to the air inlet preheating channel, the The air outlet preheating channel is connected to the gap between the inner shell and the outer shell and is arranged in the inner shell. The air inlet preheating channel and the air outlet preheating channel are connected to the bottom of the inner shell. The inner shell lifting rod is fixedly arranged on both sides of the inner shell and movably mounted on the upper edge of the outer shell. The upper cover plate covers the top of the outer shell. The upper cover plate is provided with through holes corresponding to the air outlet preheating channel and the air inlet preheating channel. The immersion water inlet passes through the through holes of the upper cover plate and is inserted into the air inlet preheating channel. The fixer is arranged at the upper end of the immersion water inlet to fix the invasive water inlet to the air inlet preheating channel.

[0006] Furthermore, the outer shell material includes plain carbon steel, stainless steel, tinplate, magnesium refractory material or aluminum refractory material, and the inner shell material includes plain carbon steel, stainless steel or tinplate.

[0007] Furthermore, the width of the gap between the side walls of the inner shell and the outer shell is 5 to 20 cm.

[0008] Furthermore, the material of the fixture includes plain carbon steel or stainless steel, the inner lining of the fixture is provided with a refractory material, the refractory material includes refractory wool, and the thickness of the refractory material is 5 to 20 mm.

[0009] Furthermore, the inner diameter of the outlet air preheating channel is 100-500 mm, the number of the outlet air preheating channels is 4-16, and the inner diameter of the inlet air preheating channel is 200-600 mm.

[0010] Furthermore, the volume of the inner shell protective slag is 0.5 to 2 m 3 .

[0011] Furthermore, the exterior of the submerged nozzle is coated with a refractory material having a thickness of 1 to 10 cm, and the refractory material is refractory wool.

[0012] A method for preheating an immersion nozzle and a casting protection slag together, wherein the immersion nozzle is fixed on a fixture, and the fixture is placed in the air inlet preheating channel of the preheating device, the casting protection slag is placed in the inner shell, and then the inner shell is placed in the outer shell, ensuring that the gap between the inner shell and the outer shell is unobstructed, and the spray gun system is started, the air-fuel ratio R of the spray gun system is 4 to 7, and the gas flow rate is adjusted to 10 to 30m 3 / h, preheat with low fire, the preheating time is 15 to 30 minutes, after preheating, the water outlet temperature reaches 300 to 500℃, after the preheating with low fire, increase the gas flow to 40 to 60m 3 / h, and heat up with high fire for 30 to 50 minutes. After baking, the nozzle temperature reaches 1000 to 1200℃. During the preheating process, the smoke generated by the spray gun system circulates through the gaps and the air outlet preheating channel, exchanges heat with the start-casting protective slag in the inner shell, and preheats the protective slag. After the preheating is completed, the spray gun system is turned off, and the inner shell is lifted out of the outer shell through the inner shell lifting rod, the preheated start-casting protective slag is poured out, and the preheated immersion nozzle is removed from the holder and fixed on the middle package.

[0013] Furthermore, the air-fuel ratio R of the spray gun system in the low-fire baking preheating stage is 6, and the air-fuel ratio R in the high-fire heating stage is 4.

[0014] Compared with the prior art, the present invention has the following beneficial effects:

[0015] It can achieve simultaneous preheating of the submerged nozzle and the protective slag, improve the preheating effect and efficiency of the submerged nozzle, avoid the decarburization and loosening of the nozzle refractory due to oxidation, which leads to blockage of the nozzle inner wall, improve the preheating efficiency, reduce energy consumption, and use the preheating flue gas to preheat the casting protective slag, effectively reducing the risk of condensation of the molten steel caused by the large amount of heat absorbed by the protective slag during the continuous casting process, thereby improving the stability of continuous casting production and product quality, and can also improve energy utilization and reduce continuous casting production costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a structural schematic diagram of the present invention.

[0017] Figure 2 It is a structural schematic diagram of the immersion nozzle and the fixer of the present invention.

[0018] Figure 3 It is a schematic diagram of the cross-sectional structure of the present invention.

[0019] Figure: 1. Outer shell 2. Inner shell 3. Spray gun system 4. Inner shell lifting rod 5. Gap 6. Exhaust preheating channel 7. Inlet preheating channel 8. Upper cover 9. Immersed nozzle 10. Fixer DETAILED DESCRIPTION

[0020] The specific embodiments of the present invention will be further described below with reference to the accompanying drawings:

[0021] See Figure 1-3, is a schematic diagram of the structure of the present invention. The present invention provides a device and method for preheating a submerged nozzle and casting protective slag together, comprising an outer shell 1, an inner shell 2, a spray gun system 3, an inner shell lifting rod 4, an air outlet preheating channel 6, an air inlet preheating channel 7, an upper cover plate 8, a fixer 10 and a submerged nozzle 9. The inner shell 2 is closed at the bottom and arranged in the outer shell 1 with an upper opening. The inner shell 2 is used to contain and preheat the protective slag. A gap 5 is left between the side walls of the inner shell 2 and the outer shell 1. The air inlet preheating channel 7 is arranged in the inner shell 2. The spray gun system 3 is arranged directly above the air inlet preheating channel 7, and the nozzle of the spray gun system 3 corresponds to the air inlet preheating channel 7. The outlet preheating channel 6 is connected to the gap 5 between the inner shell 2 and the outer shell 1 and is arranged in the inner shell 2. The inlet preheating channel 7 and the outlet preheating channel 6 are connected to the bottom of the inner shell 2. The inner shell 2 lifting rod is fixedly arranged on both sides of the inner shell 2 and movably mounted on the upper edge of the outer shell 1. The upper cover plate 8 covers the top of the outer shell 1. The upper cover plate 8 is provided with through holes corresponding to the outlet preheating channel 6 and the inlet preheating channel 7. The immersion water inlet 9 passes through the through hole of the upper cover plate 8 and is inserted into the inlet preheating channel 7. The fixer 10 is arranged at the upper end of the immersion water inlet 9 to fix the invasive water inlet to the inlet preheating channel 7.

[0022] The shell 1 of the preheating device for the submerged water nozzle 9 and the casting protective slag is used to accommodate the inner shell 2, the air outlet preheating channel 6 and the air inlet preheating channel 7. It is made of stainless steel, has good corrosion resistance and high temperature resistance, has a size of 1m×1m×1.5m, and is open at the top.

[0023] The inner shell 2 of the immersion nozzle 9 and the protective slag preheating device is used to contain and preheat the protective slag, complete the heat exchange between the waste heat flue gas and the protective slag, and is made of stainless steel, with a size of 0.8m×0.8m×1.4m and a sealed bottom.

[0024] A 10 cm gap 5 is left between the side walls of the inner shell 2 and the outer shell 1 for smoke to circulate.

[0025] The spray gun system 3 is used to provide a heat source to preheat the submerged nozzle 9 and the protective slag. The fuel of the spray gun system 3 is coal gas, natural gas, methane, etc. The spray gun system 3 can be heated by gas combustion. During the preheating process, the nozzle can move up and down along the axis. In this device, coal gas is selected as the fuel, and the heat generated by the gas combustion is introduced into the preheating device through the spray gun. The spray gun system 3 adjusts the air-fuel ratio R=4 to achieve the best preheating effect.

[0026] The inner shell lifting rod 4 is used to lift the inner shell 2 out of the outer shell 1 and tilt to pour out the protective slag. The inner shell lifting rod 4 is connected to the outer shell 1, and the inner shell lifting rod 4 is used to place the inner shell 2 and lift it out of the outer shell 1.

[0027] The air inlet preheating channel 7 is used to place and preheat the immersion nozzle 9. The air inlet channel and the air outlet channel are connected to the bottom of the inner shell 2, providing a waste heat flue gas channel in the outer shell 1 of the preheating device for heat generated by the nozzle of the spray gun system 3. The air inlet preheating channel 7 is located in the center of the inner shell 2, corresponding to the spray gun system 3. The gas flame enters the preheating device through the air inlet channel. The inner diameter of the air inlet preheating channel 7 is 200-600 mm.

[0028] The outlet preheating channel 6 is used for the flow of flue gas generated by the nozzle of the spray gun system 3 and for heat exchange with the protective slag. The heat and flue gas generated after the coal gas enters the air preheating channel 7 and burns flow through the gap 5 and the outlet preheating channel 6 and are discharged from the preheating box. The inner diameter is 300 mm, and there are 8 of them, which are evenly distributed in the inner shell 2.

[0029] The submerged nozzle 9 and the pouring protection slag common preheating device are made of a composite material of metal and refractory material, the metal material is stainless steel, and the refractory material is asbestos.

[0030] The upper cover plate 8 is used to reduce heat dissipation during the preheating process, and is used to seal the top of the shell 1 to reduce heat dissipation during the preheating process. It is made of stainless steel and has good sealing and high temperature resistance. At the same time, the openings match the air inlet preheating channel 7 and the air outlet preheating channel 6.

[0031] The holder 10 is used to fix, lift and carry the submerged nozzle 9. The materials of the holder 10 include: plain carbon steel, stainless steel. The holder 10 is lined with soft refractory material to avoid damaging the nozzle, and to facilitate preheating operation. The refractory material includes: refractory cotton; optionally, the refractory material has a thickness of 5 to 20 mm. In this embodiment, it is made of stainless steel and lined with 5 mm thick refractory cotton.

[0032] The protective slag volume of the inner shell 2 is 0.5 to 2 m 3 .

[0033] The submerged nozzle 9 is externally coated with a refractory material having a thickness of 1 to 10 cm, and the refractory material is refractory wool.

[0034] A method for preheating an immersion nozzle and casting protection slag together, fixing the immersion nozzle 9 on a holder 10, and placing the holder 10 in the air inlet preheating channel 7 of the preheating device, placing the casting protection slag in the inner shell 2, and then placing the inner shell 2 in the outer shell 1, ensuring that the gap 5 between the inner shell 2 and the outer shell 1 is unobstructed, starting the spray gun system 3, and the spray gun system 3 can adjust the air-fuel ratio R=4 to achieve the best preheating effect, and adjusting the gas flow rate to 20m 3 / h, preheat with low fire, the preheating time is 20min, after preheating, the water outlet temperature reaches 400℃; after the preheating with low fire, increase the gas flow to 50m 3 / h, high fire heating is carried out, the high fire heating time is 40min, and the nozzle temperature reaches 1100℃ after baking.

[0035] During the preheating process, the smoke generated by the spray gun system 3 flows through the gap 5 and the air outlet preheating channel 6, and exchanges heat with the casting protection slag in the inner shell 2 to preheat the protection slag. After the preheating is completed, the spray gun system 3 is closed, and the inner shell 2 is lifted out of the outer shell 1 through the inner shell lifting rod 4, and the preheated casting protection slag is poured out. The temperature of the protection slag can reach 250°C. The preheated immersion nozzle 9 is removed from the holder 10 and fixed on the middle package.

[0036] The fuel is coal gas, methane, propane and other commonly used gas fuels in metallurgy. In this embodiment, the fuel is coal gas.

[0037] The above embodiments are implemented under the premise of the technical solution of the present invention, and detailed implementation methods and specific operation processes are given, but the protection scope of the present invention is not limited to the above embodiments. The methods used in the above embodiments are conventional methods unless otherwise specified.

Claims

1. A device for preheating both an immersion nozzle and a casting powder, characterized in that: It includes an outer shell, an inner shell, a spray gun system, an inner shell lifting rod, an outlet air preheating channel, an inlet air preheating channel, an upper cover plate, a fixer and an immersion nozzle. The bottom of the inner shell is closed and arranged in the outer shell with an opening on the top. The inner shell is used to hold and preheat the protective slag. A gap is left between the side walls of the inner shell and the outer shell. The inlet air preheating channel is arranged in the inner shell. The spray gun system is arranged just above the inlet air preheating channel, and the nozzle of the spray gun system corresponds to the inlet air preheating channel. The outlet air preheating channel is connected to the inner shell. The gap between the inner shell and the outer shell is set in the inner shell, the air inlet preheating channel and the air outlet preheating channel are connected with the bottom of the inner shell, the inner shell lifting rod is fixedly set on both sides of the inner shell and movably mounted on the upper edge of the outer shell, the upper cover plate covers the top of the outer shell, and the upper cover plate is provided with through holes corresponding to the air outlet preheating channel and the air inlet preheating channel. The immersion water inlet is inserted into the air inlet preheating channel through the through holes of the upper cover plate. The fixer is set at the upper end of the immersion water inlet to fix the immersion water inlet to the air inlet preheating channel.

2. The device for preheating a submerged nozzle and mold slag according to claim 1, characterized in that: The outer shell material includes plain carbon steel, stainless steel, tinplate, magnesium refractory material or aluminum refractory material, and the inner shell material includes plain carbon steel, stainless steel or tinplate.

3. The device for preheating a submerged nozzle and mold slag according to claim 1, characterized in that: The width of the gap between the side walls of the inner shell and the outer shell is 5 to 20 cm.

4. The device for preheating a submerged nozzle and mold slag according to claim 1, characterized in that: The material of the fixture includes ordinary carbon steel or stainless steel, and the inner lining of the fixture is provided with a refractory material, the refractory material includes refractory wool, and the thickness of the refractory material is 5 to 20 mm.

5. The device for preheating both the submerged nozzle and the casting powder according to claim 1, characterized in that: The inner diameter of the outlet air preheating channel is 100-500 mm, the number of the outlet air preheating channels is 4-16, and the inner diameter of the inlet air preheating channel is 200-600 mm.

6. The device for preheating both the submerged nozzle and the casting powder according to claim 1, characterized in that: The volume of the inner shell protective slag is 0.5 to 2 m 3 .

7. The device for preheating both the submerged nozzle and the casting powder according to claim 1, characterized in that: The exterior of the submerged nozzle is covered with a refractory material having a thickness of 1 to 10 cm, and the refractory material is refractory wool.

8. A preheating method according to any one of claims 1 to 7, characterized in that: Fix the submerged nozzle on the holder, and place the holder in the air preheating channel of the preheating device, put the casting protection slag into the inner shell, and then place the inner shell into the outer shell, making sure the gap between the inner shell and the outer shell is unobstructed, start the spray gun system, the air-fuel ratio R of the spray gun system is 4-7, and the gas flow rate is adjusted to 10-30m 3 / h, preheat with low fire, the preheating time is 15 to 30 minutes, after preheating, the water outlet temperature reaches 300 to 500℃, after the preheating with low fire, increase the gas flow to 40 to 60m 3 / h, and heat up with high fire for 30 to 50 minutes. After baking, the nozzle temperature reaches 1000 to 1200℃. During the preheating process, the smoke generated by the spray gun system circulates through the gaps and the air outlet preheating channel, exchanges heat with the start-casting protective slag in the inner shell, and preheats the protective slag. After the preheating is completed, the spray gun system is turned off, and the inner shell is lifted out of the outer shell through the inner shell lifting rod, the preheated start-casting protective slag is poured out, and the preheated immersion nozzle is removed from the holder and fixed on the middle package.

9. A method for preheating a submerged nozzle and mold slag together according to claim 8, characterized in that: The air-fuel ratio R of the spray gun system in the low-fire baking preheating stage is 6, and the air-fuel ratio R of the high-fire heating stage is 4.

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