Method for treating high temperature of side wall of hearth

Abstract

The invention relates to the technical field of steel smelting equipment, in particular to a method for treating high temperature of the side wall of a hearth. The method comprises the following steps that S1, the incoming water temperature is reduced to T1 to be lower than the normal incoming water temperature T2, the silicon content in molten iron is controlled to be 0.25-0.4%, the sulfur content is controlled to be 0.02-0.024%, the iron notch depth is controlled to be 3000 mm or above, and the mud beating amount is controlled to be 440 mm or above; s2, when the thickness of the carbon bricks is lower than 550 mm, the temperature of the furnace shell is higher than 90 DEG C and the heat flow intensity is larger than 12000, the blast furnace small sleeve is changed into a straight tuyere with the diameter of 550 mm, and the length of the tuyere is lengthened by 50 mm; s3, when the temperature of the side wall of the hearth is higher than the temperature upper limit value, preparing high titanium balls, and when the titanium content in the molten iron is 0.8-1.0% and the temperature of the hearth is reduced to 450 DEG C, stopping preparing the high titanium balls; and S4, during damping down of the blast furnace, hot face grouting is conducted on the side wall of the hearth, and the upper limit of the grouting pressure is P. The technical problems of high coke ratio and high furnace protection cost caused by reduction of the temperature of the side wall of the hearth by feeding the titanium-containing material at the tuyere in the prior art are effectively solved.

Description

Technical Field

[0001] This invention relates to the field of steel smelting equipment technology, and in particular to a method for controlling high temperature on the sidewall of the furnace hearth. Background Technology

[0002] Blast furnaces are crucial equipment in the steelmaking process. Operating under high temperature and pressure for extended periods during smelting not only affects the normal operation of the equipment but also poses a threat to the health of operators. In particular, the high internal temperature and other factors contribute to increased sidewall temperatures, which not only disrupts normal operation but may also severely impact the furnace's safety and lifespan.

[0003] Currently, in response to the high temperature of the blast furnace sidewall, steel plants often use the method of adding a large amount of titanium-containing materials from the top of the blast furnace or the tuyeres to protect the furnace. The titanium-containing materials react chemically with elements such as carbon and nitrogen in the high-temperature blast furnace environment to generate Ti(C,N) compounds with high melting points and strong corrosion resistance. These compounds can firmly adhere to the blast furnace sidewall, forming a protective layer, thereby effectively resisting the erosion of high temperature and corrosive gases inside the furnace, thus improving the service life of the blast furnace and ensuring its normal operation.

[0004] While the above methods can reduce the temperature of the hearth sidewall, the Si content in the molten iron needs to be significantly increased during the furnace protection process to ensure the furnace protection effect. This will directly lead to an increase in the coke ratio (i.e., the ratio of the amount of coke consumed in the ironmaking process to the amount of molten iron produced), which in turn leads to a decrease in the amount of iron tapped from the blast furnace, resulting in a reduction in the total output of pig iron. In addition, due to the high cost of titanium-containing materials, the operation of feeding titanium-containing materials through the tuyeres will also greatly increase the cost of furnace protection. Summary of the Invention

[0005] This invention provides a method for controlling the high temperature of the furnace hearth sidewall, thereby solving the technical problem in the prior art where feeding titanium-containing materials into the tuyeres to reduce the temperature of the furnace hearth sidewall leads to a high coke ratio and high furnace protection costs.

[0006] To solve the above problems, the method for controlling high furnace hearth sidewall temperature provided by the present invention adopts the following technical solution:

[0007] A method for controlling high temperature on the sidewall of a furnace hearth includes the following steps:

[0008] S1: Lower the inlet water temperature to T1, making it lower than the normal inlet water temperature T2, control the silicon content in the molten iron to 0.25-0.4%, the sulfur content to 0.02-0.024%, the taphole depth to 3000mm or more, and the mud removal amount to 440mm or more;

[0009] S2: When the carbon brick thickness is less than 550mm, the furnace shell temperature is higher than 90℃ and the heat flux intensity is greater than 12000, the blast furnace sleeve is replaced with a straight tuyer with a diameter of 550mm and the tuyer length is increased by 50mm.

[0010] S3: When the temperature of the hearth sidewall is higher than the upper temperature limit, high-titanium balls are added to gradually increase the titanium content in the molten iron. When the titanium content in the molten iron is 0.8-1.0% and the hearth temperature drops to 450℃, the addition of high-titanium balls is stopped.

[0011] S4: When the blast furnace is shut down, hot surface grouting is performed on the side wall of the hearth, with the upper limit of the grouting pressure being P.

[0012] The beneficial effects of the method for controlling high temperature on the sidewall of the furnace hearth provided by this invention are:

[0013] 1. By lowering the temperature of the incoming water, it can have a larger heat capacity to absorb the heat released inside the blast furnace, thereby increasing the cooling effect of the cooling system and reducing the temperature of the hearth sidewall.

[0014] 2. By controlling the silicon content in the molten iron to 0.25-0.4%, the molten iron can be kept within a reasonable temperature range, which helps to stabilize the temperature field of the hearth sidewall. By controlling the sulfur content in the molten iron to 0.02-0.024%, the corrosion of the refractory material of the hearth sidewall by sulfur can be reduced, thereby protecting the hearth sidewall and reducing its temperature. An effective solidified iron layer can be formed between the molten iron and the carbon bricks, protecting the carbon bricks from further corrosion.

[0015] 3. By replacing the blast furnace tuyeres with straight tuyeres of 550mm in diameter, the air delivery method of straight tuyeres is more direct compared to other types of tuyeres. This allows for more effective delivery of cold air into the blast furnace, where it can exchange heat with the high-temperature materials inside, thereby rapidly reducing the hearth temperature. Compared to conventional tuyeres, tuyeres of 550mm in diameter can concentrate the air volume and increase the air velocity, resulting in stronger contact between the cold air and the inner wall of the hearth, improving heat exchange efficiency and more effectively reducing the hearth temperature. Increasing the length of the tuyeres by 50mm can extend the flow path of the cold air within the tuyeres, increasing the heat exchange time between the cold air and the tuyeres material, resulting in lower temperatures of the cold air before it enters the blast furnace, further improving the cooling effect.

[0016] 4. High-titanium balls can react chemically with elements such as carbon and nitrogen in the furnace at high temperatures to generate Ti(C,N) compounds with high melting points and strong corrosion resistance. These compounds can firmly adhere to the side wall of the hearth, forming a protective layer, thereby effectively resisting the erosion of high temperature and corrosive gases in the furnace, gradually increasing the titanium content in the molten iron, and avoiding the situation of hearth accumulation and reduced blast furnace output caused by adding too much titanium at one time.

[0017] 5. Grouting on the hot surface during blast furnace shutdown can fill the gap between the blast furnace hearth sidewall and the cooling wall without affecting blast furnace production, preventing gas leakage, thereby reducing heat loss, lowering the temperature of the hearth sidewall, and improving the cooling effect of the cooling wall, so that the cooling water can more effectively absorb and remove the heat from the hearth sidewall, further reducing the temperature.

[0018] Through the above-mentioned settings, the present invention has improved and upgraded the existing furnace hearth sidewall cooling method, effectively solving the technical problems of high coke ratio and high furnace protection cost caused by feeding titanium-containing materials into the tuyeres to reduce the furnace hearth sidewall temperature.

[0019] Furthermore, the titanium content in the high-titanium spheres is 0.7%.

[0020] Furthermore, the incoming water temperature T2 is 40°C.

[0021] Furthermore, the incoming water temperature T1 is less than 38°C.

[0022] Furthermore, the hot-surface grouting includes the following steps:

[0023] a. Grouting holes are opened on the side wall of the furnace hearth, extending to the outer surface of the carbon bricks;

[0024] b. Inject composite fiber wear-resistant castable into the grouting hole;

[0025] c. Stop grouting when the grouting pressure reaches P.

[0026] Furthermore, the upper limit of the grouting pressure P is 25 MPa.

[0027] Furthermore, the hot-surface grouting is performed three times.

[0028] Furthermore, thermocouples are installed inside the blast furnace and are connected to the hearth erosion model software to monitor the furnace temperature in real time. The thickness of the carbon bricks is calculated synchronously using the measured temperature and the hearth erosion model software.

[0029] Furthermore, the number of thermocouples is multiple. Attached Figure Description

[0030] The above and other objects, features, and advantages of exemplary embodiments of the present invention will become readily apparent upon reading the following detailed description with reference to the accompanying drawings. In the drawings, several embodiments of the invention are illustrated by way of example and not limitation, and like or corresponding reference numerals denote like or corresponding parts, wherein:

[0031] Figure 1 The flowchart illustrates the method for controlling high temperature on the sidewall of the furnace hearth provided by this invention. Detailed Implementation

[0032] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Those skilled in the art should understand that the embodiments described below are only some, not all, of the embodiments disclosed. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0033] It should be noted that the main concept of the method for controlling high temperature on the hearth sidewall provided by this invention is as follows: Firstly, by reducing the temperature of the incoming water, the heat capacity of the incoming water is increased, thereby enhancing the cooling effect of the cooling system. Secondly, by controlling the silicon and sulfur content in the molten iron, the molten iron can be kept within a reasonable temperature range, reducing the erosion of the refractory material on the hearth sidewall by the molten iron, and forming an effective solidified iron layer between the molten iron and the carbon bricks to protect the hearth sidewall and stabilize its temperature field. Thirdly, by replacing the blast furnace jacket with a straight tuyere with a diameter of 550mm and increasing the tuyere length by 50mm, cold air can be delivered into the blast furnace more directly and centrally, improving the heat exchange efficiency between the cold air and the high-temperature materials inside the furnace, extending the flow path of the cold air within the tuyere, increasing the heat exchange time between the cold air and the tuyere material, and further improving the cooling effect. Fourthly, by adding high-titanium balls, high-melting-point, highly corrosion-resistant T-type blast furnace linings can be generated that can adhere to the hearth sidewall. The i(C,N) compounds are used to resist the erosion of high temperatures and corrosive gases inside the furnace. Hot-surface grouting of the hearth sidewalls fills the gaps between the hearth sidewalls and the cooling walls, preventing gas leakage and thus reducing heat loss and lowering the hearth sidewall temperature. This design effectively solves the technical problems of high coke ratios and high furnace protection costs associated with feeding titanium-containing materials into the tuyeres to lower the hearth sidewall temperature.

[0034] After introducing the basic principles of the present invention, various non-limiting embodiments of the present invention are described in detail below. Any number of elements in the accompanying drawings is for illustrative purposes only and not for limitation, and any naming is for distinction only and has no limiting meaning.

[0035] The principles and spirit of the present invention will be explained in detail below with reference to several representative embodiments.

[0036] Example 1 of the method for controlling high temperature on the sidewall of the furnace hearth provided by the present invention:

[0037] like Figure 1 As shown, the method for controlling the high temperature of the furnace sidewall includes the following steps:

[0038] S1: Lower the inlet water temperature to T1, making it lower than the normal inlet water temperature T2, control the silicon content in the molten iron to 0.25-0.4%, the sulfur content to 0.02-0.024%, the taphole depth to 3000mm or more, and the mud removal amount to 440mm or more;

[0039] S2: When the carbon brick thickness is less than 550mm, the furnace shell temperature is higher than 90℃ and the heat flux intensity is greater than 12000, the blast furnace sleeve is replaced with a straight tuyer with a diameter of 550mm and the tuyer length is increased by 50mm.

[0040] S3: When the temperature of the hearth sidewall is higher than the upper temperature limit, high-titanium balls are added to gradually increase the titanium content in the molten iron. When the titanium content in the molten iron is 0.8-1.0% and the hearth temperature drops to 450℃, the addition of high-titanium balls is stopped.

[0041] S4: When the blast furnace is shut down, hot surface grouting is performed on the side wall of the hearth, with the upper limit of the grouting pressure being P.

[0042] Among them, the titanium content in the high-titanium ball is 0.7%, the inlet water temperature T2 is 40℃, the inlet water temperature T1 is less than 38℃, the upper limit of the grouting pressure P is 25MPa, and the number of hot surface groutings is three.

[0043] Specifically, hot-face grouting includes the following steps:

[0044] a. Grouting holes are opened on the side wall of the furnace hearth, extending to the outer surface of the carbon bricks;

[0045] b. Inject composite fiber wear-resistant castable into the grouting hole;

[0046] c. Stop grouting when the grouting pressure reaches 25MPa.

[0047] In addition, multiple thermocouples are installed inside the blast furnace. These thermocouples are connected to the hearth erosion model software to monitor the furnace temperature in real time and to calculate the carbon brick thickness synchronously using the temperature measured by the thermocouples and the hearth erosion model software.

[0048] In addition, it should be noted that when the temperature of the furnace hearth sidewall measured by the thermocouple reaches 500℃, cooling measures should be taken to control the further development of the furnace hearth sidewall temperature and prevent its maximum value from exceeding 550℃. If the diameter of the blast furnace sleeve is changed to a 550mm straight tuyer, and the heat flux intensity is again greater than 12000, the tuyer should be blocked and the furnace should be protected. The tuyer should be opened again after the temperature of the furnace hearth sidewall drops to 400℃.

[0049] Example 2 of the method for controlling high temperature on the sidewall of the furnace hearth provided by the present invention:

[0050] Its main difference from Example 1 is:

[0051] In Example 1, the hot surface grouting was performed three times.

[0052] In this embodiment, the number of hot-surface grouting operations is determined by the temperature of the furnace hearth sidewall. Hot-surface grouting can be performed when the temperature of the furnace hearth sidewall is high.

[0053] Based on the above description in this specification, those skilled in the art will also understand that the following terms, such as "upper," "lower," "front," "rear," "left," "right," "width," "horizontal," "top," "bottom," "inner," and "outer," which indicate orientation or positional relationships, are based on the orientation or positional relationships shown in the accompanying drawings of this specification. They are only for the purpose of facilitating the explanation of the present invention and simplifying the description, and do not explicitly or implicitly suggest that the device or element involved must have the specific orientation, or be constructed and operated in a specific orientation. Therefore, the above-mentioned orientation or positional relationship terms should not be understood or interpreted as limitations on the present invention.

[0054] In addition, in the description of this specification, "multiple" means at least two, such as two, three or more, etc., unless otherwise expressly and specifically defined.

Claims

1. A method of managing high temperature in the side wall of a hearth, characterized by, The method comprises the following steps: S1: reducing the temperature of incoming water to T1, which is lower than the normal temperature T2 of incoming water, controlling the silicon content in molten iron to be 0.25-0.4%, the sulfur content to be 0.02-0.024%, the iron notch depth to be more than 3000 mm, and the clay hitting amount to be more than 440 mm; S2: when the carbon brick thickness is less than 550 mm, the furnace shell temperature is higher than 90℃, and the heat flow intensity is greater than 12000, the small sleeve of the blast furnace is changed into a straight tuyere with a diameter of 550 mm, and the tuyere length is lengthened by 50 mm; S3: when the sidewall temperature of the hearth is higher than the upper limit temperature, high-titanium balls are added to gradually increase the titanium content in the molten iron; when the titanium content in the molten iron is 0.8-1.0% and the hearth temperature drops to 450℃, the addition of high-titanium balls is stopped; S4: when the blast furnace is blown down, hot-face grouting is performed on the sidewall of the hearth, and the upper limit of the grouting pressure is P.

2. The method of managing high furnace wall temperatures of claim 1, wherein, The titanium content in the high-titanium ball is 0.7%.

3. The method of managing high temperature in the side wall of a furnace hearth of claim 1 or 2, wherein, The temperature T2 of the incoming water is 40℃.

4. The method of managing high temperature in the side wall of a furnace hearth of claim 3, wherein, The temperature T1 of the incoming water is less than 38℃.

5. The method of managing high temperature in the side wall of a furnace hearth of claim 1 or 2, wherein, The hot-face grouting comprises the following steps: a. grouting holes are opened on the sidewall of the hearth, and the grouting holes extend to the outer surface of the carbon brick; b. composite fiber wear-resistant castable is injected into the grouting holes; c. grouting is stopped when the grouting pressure reaches P.

6. The method of managing high temperature in the side wall of a furnace hearth of claim 5, wherein, The upper limit P of the grouting pressure is 25 MPa.

7. The method of managing high temperature in a furnace side wall according to claim 6, wherein, The hot-face grouting is performed three times.

8. The method of managing high temperature in the side wall of a furnace hearth of claim 1 or 2, wherein, A thermocouple is installed in the blast furnace, and the thermocouple is connected to a hearth erosion model software signal to monitor the temperature in the furnace in real time, and the carbon brick thickness is calculated synchronously by the measured temperature and the hearth erosion model software.

9. The method of managing high temperature in a furnace side wall according to claim 8, wherein, The number of the thermocouples is multiple.

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