Online oven drying method for hot blast stove

Abstract

The invention discloses an online oven drying method for a hot blast stove. The method comprises the following steps: 1) hot combustion-supporting air of an in-use hot-blast stove provides preheated hot combustion-supporting air for a newly-built hot-blast stove through a pipeline so as to perform low-temperature section oven drying on the newly-built hot-blast stove; (2) supplying blast furnace hot air to the newly-built hot blast stove through a blast furnace hot air pipeline of the in-use hot blast stove so as to carry out heating section oven drying on the newly-built hot blast stove; according to the method, an existing hot-blast stove production system is utilized, an oven device does not need to be additionally installed and dismantled, the method is safer and more reliable, and meanwhile the labor intensity and the investment cost are reduced.

Description

Technical Field

[0001] This invention relates to an online drying method for a hot blast stove. Background Technology

[0002] With the increasing demands for safe, efficient, low-consumption, energy-saving, and low-cost production in blast furnaces, the traditional three hot blast stoves in blast furnace workshops are no longer sufficient. To increase blast temperature and reduce the blast furnace fuel ratio, many blast furnace workshops require the addition of one more hot blast stove to meet normal production needs. Furthermore, if one of the original three hot blast stoves fails and requires cooling for repair, the blast furnace must shut down, directly impacting production. With the addition of one hot blast stove, there are a total of four. If one hot blast stove fails, it can be cooled for repair while the remaining three continue normal production without affecting overall blast furnace operations.

[0003] Hot blast stove baking is a crucial process that must be completed after installation and before commissioning. The newly constructed furnace walls utilize a large amount of monolithic refractory and insulating castable as the furnace lining to prevent heat loss. Especially for furnaces with insulated wall structures, a significant amount of moisture remains in the insulating castable during construction. If this free water is not thoroughly dried before commissioning, the moisture inside the furnace walls will evaporate upon heating, causing expansion and pressure, leading to cracks, deformation, and, in severe cases, large-scale wall collapse. Therefore, before commissioning, detailed baking curves and operating procedures should be developed based on the specific furnace type, the amount of wear-resistant refractory and insulating material used, and the actual thickness of the furnace walls. Simultaneously, baking allows for physicochemical reactions in the wear-resistant refractory materials, increasing their strength and ensuring the permanent stability of the masonry structure. This ensures the hot blast stove can operate safely, normally, and at full load for extended periods at high temperatures, achieving high production and efficiency.

[0004] Traditional hot blast stove drying methods involve installing specialized drying equipment on the hot blast stove after its construction. The entire drying process utilizes high-temperature flue gas generated by burning a combustible medium (typically blast furnace gas, natural gas, or coke oven gas) to dry the stove. The drying equipment is then removed once the drying process is complete. Hot blast stove drying is fuel-intensive, requires the installation and dismantling of specialized equipment, involves high labor intensity, and incurs significant initial investment costs. Summary of the Invention

[0005] To address the aforementioned shortcomings, this invention proposes an online hot blast stove drying method. This method achieves the hot blast stove drying requirements without the need for additional dedicated drying equipment or continuous furnace firing, while ensuring normal production and meeting the requirements of safety, low consumption, and environmental protection. This minimizes labor intensity, saves energy, and reduces investment and operating costs.

[0006] To achieve the above objectives, the present invention provides an online hot blast stove drying method, wherein the hot blast stove includes two or more existing hot blast stoves and one newly built hot blast stove; each hot blast stove is equipped with a blast furnace cold air duct, a hot combustion air duct, a blast furnace hot blast duct, a gas duct, a pressure exhaust gas duct, a flue gas duct, and a burner; Among them, the hot air pipeline of the in-use hot blast stove is connected to the hot air pipeline of the newly built hot blast stove through a pipeline; the hot blast pipeline of the in-use hot blast stove and the hot blast pipeline of the blast furnace are respectively connected to the hot blast pipeline of the newly built hot blast stove through pipelines. The method includes: 1) The hot combustion air of the existing hot blast stove is supplied to the newly built hot blast stove through pipelines after preheating, so as to perform low-temperature baking of the new hot blast stove; 2) The hot blast pipeline of the existing hot blast stove supplies hot blast to the newly built hot blast stove through the pipeline to carry out the heating section baking of the new hot blast stove; 3) Finally, the furnace is heated in a high-temperature section using the burners on the hot blast stove.

[0007] Furthermore, the temperature range of the low-temperature oven is from room temperature to approximately 200°C, and the heating rate is 1~1.5°C / h.

[0008] Furthermore, the temperature range of the heating section oven is from approximately 200°C to approximately 900°C, and the heating rate is 1~4.5°C / h.

[0009] Furthermore, the temperature range of the high-temperature section oven is approximately 900°C to approximately 1200°C, and the heating rate is 12~13°C / h.

[0010] Furthermore, the newly built hot blast stove is also equipped with a pressure relief pipe and a flue gas pipe; a pressure relief valve is installed on the pressure relief pipe, and a flue gas valve is installed on the flue gas pipe. When baking the furnace in the low-temperature section and the heating section, close the flue valve and open the pressure relief valve. The exhaust gas is discharged through the pressure relief pipe. When baking the furnace at high temperature, close the pressure relief valve and open the flue valve, and the exhaust gas is discharged through the flue gas duct.

[0011] The present invention has the following advantages: (1) The present invention utilizes the existing production hot air furnace system, without the need for additional installation and dismantling of the oven drying device, making it safer and more reliable, while reducing labor intensity and investment costs.

[0012] (2) In this invention, the low-temperature section of the hot blast stove is dried by using preheated hot combustion air, and the heating section of the hot blast stove is dried by using hot blast furnace air. Since the gas is not directly burned and consumed, the gas consumption and flue gas emissions are reduced, making it more energy-efficient and environmentally friendly. Attached Figure Description

[0013] Figure 1 This is a schematic diagram of the process of the present invention.

[0014] Icon labels: 1—New hot blast stove; 2—Blast furnace cold blast duct; 3—Hot combustion air duct; 4—Blast furnace hot blast duct; 5—Gas duct; 6—Pressure relief flue gas duct; 7—Flue gas duct; 8—Pressure equalization valve; 9—Cold blast valve; 10—Combustion air combustion valve; 11—Combustion air regulating valve; 12—Hot blast valve; 13—Gas combustion valve; 14—Gas shut-off valve; 15—Gas regulating valve; 16—Pressure relief valve; 17—Flue gas valve; 18—Existing hot blast stove in normal operation. Detailed Implementation

[0015] The embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0016] In the description of this invention, it should be understood that the terms "center", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "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.

[0017] The terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0018] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0019] Example 1 like Figure 1 As shown, there are already 3 hot blast stoves in use, and 1 new hot blast stove will be built.

[0020] This embodiment describes an online hot blast stove drying method. The newly constructed hot blast stove system mainly includes a hot combustion air duct 3, a gas duct 5, a blast furnace hot blast duct 4, a blast furnace cold blast duct 2, and a flue gas duct 7. The hot blast stove valves mainly include a hot blast valve 12, a cold blast valve 9, a pressure equalization valve 8, a pressure relief valve 16, a gas combustion valve 13, a gas shut-off valve 14, a combustion air combustion valve 10, a combustion air regulating valve 11, a gas regulating valve 15, and a flue valve 17. The furnace is dried in a low-temperature section through the preheated hot combustion air duct 3, then in a high-temperature section through the blast furnace hot blast duct 4, and finally in a high-temperature section using the hot blast stove's own burner, thus achieving the desired drying effect.

[0021] In this embodiment, the temperature range of the low-temperature furnace is from room temperature to approximately 200°C (this temperature is not a fixed value and can be adjusted according to the requirements of the hot blast furnace baking curve and the maximum temperature of the hot combustion air after heat exchange). Using the preheated hot combustion air pipeline 3, the opening of the combustion air combustion valve 10 is adjusted, the pressure relief valve 16 is opened, and the flue valve 17 is closed to achieve a heating rate control of 1~1.5°C / h, thus completing the low-temperature furnace baking task.

[0022] In this embodiment, the temperature range of the heating stage furnace is approximately 200°C to approximately 900°C (this temperature is not a fixed value and can be adjusted according to the requirements of the hot blast stove furnace baking curve). The pressure equalization valve 8 of the hot blast stove 1 is opened, and the blast furnace cold air pipe 2 is poured into the hot blast stove 1 to establish a basic airflow. The temperature of the blast furnace cold air is 200~280°C. After the pressure equalization of the hot blast stove 1 is completed, the hot air valve 12 and the pressure relief valve 16 are opened. According to the requirements of the hot blast stove furnace baking curve, the temperature of the dome is slowly increased, and the opening of the hot air valve 12 and the pressure relief valve 16 is adjusted to achieve a heating rate control of 1~4.5°C / h, thereby completing the furnace baking temperature control operation in the heating stage.

[0023] In this embodiment, the temperature range of the high-temperature section of the furnace is approximately 900°C to approximately 1200°C (this temperature is not a fixed value and can be adjusted according to the requirements of the hot blast furnace furnace drying curve). When the temperature reaches 900°C, the hot blast furnace 1 is depressurized, the flue valve 17 is opened, and the furnace is switched to self-burning furnace drying. The gas combustion valve 13 and the combustion air combustion valve 10 are opened. According to the requirements of the hot blast furnace furnace drying curve, the temperature at the top of the furnace is slowly increased, and the opening of the gas regulating valve 15 and the combustion air regulating valve 11 is adjusted. The final high-temperature stage furnace drying task is completed according to the temperature rise curve.

[0024] Example 2 As a variation of the present invention, it is also applicable to the maintenance of hot blast stoves after they have cooled down. There are already 4 hot blast stoves, of which 1 hot blast stove is undergoing maintenance after it has cooled down, while the other 3 hot blast stoves are in normal production. The hot blast stoves are then dried after maintenance.

[0025] like Figure 1As shown, in this embodiment, the hot blast stove online baking method involves the hot blast stove 1 after cold furnace maintenance using the existing hot blast stove system 18 medium, equipment and control, etc. First, it uses the preheated hot combustion air pipeline 3 for low-temperature baking, then uses the blast furnace hot blast pipeline 4 for heating baking, and finally uses the hot blast stove 1's own burner to burn the furnace for high-temperature baking, thus achieving the baking effect.

[0026] In this embodiment, the temperature range of the low-temperature furnace is from room temperature to approximately 200°C (this temperature is not a fixed value and can be adjusted according to the requirements of the hot blast furnace baking curve and the maximum temperature of the hot combustion air after heat exchange). Using the preheated hot combustion air pipeline 3, the opening of the combustion air combustion valve 10 is adjusted, the pressure relief valve 16 is opened, and the flue valve 17 is closed to achieve a heating rate control of 1~1.5°C / h, thus completing the low-temperature furnace baking task.

[0027] In this embodiment, the temperature range of the heating stage furnace is approximately 200°C to approximately 900°C (this temperature is not a fixed value and can be adjusted according to the requirements of the hot blast stove furnace baking curve). The pressure equalization valve 8 of the hot blast stove 1 is opened, and the blast furnace cold air pipe 2 is poured into the hot blast stove 1 to establish a basic airflow. The temperature of the blast furnace cold air is 200~280°C. After the pressure equalization of the hot blast stove 1 is completed, the hot air valve 12 and the pressure relief valve 16 are opened. According to the requirements of the hot blast stove furnace baking curve, the temperature of the dome is slowly increased, and the opening of the hot air valve 12 and the pressure relief valve 16 is adjusted to achieve a heating rate control of 1~4.5°C / h, thereby completing the furnace baking temperature control operation in the heating stage.

[0028] In this embodiment, the temperature range of the high-temperature section of the furnace is approximately 900°C to approximately 1200°C (this temperature is not a fixed value and can be adjusted according to the requirements of the hot blast furnace furnace drying curve). When the temperature reaches 900°C, the hot blast furnace 1 is depressurized, the flue valve 17 is opened, and the furnace is switched to self-burning furnace drying. The gas combustion valve 13 and the combustion air combustion valve 10 are opened. According to the requirements of the hot blast furnace furnace drying curve, the temperature at the top of the furnace is slowly increased, and the opening of the gas regulating valve 15 and the combustion air regulating valve 11 is adjusted. The final high-temperature stage furnace drying task is completed according to the temperature rise curve.

[0029] The present invention has been described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the embodiments described above. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present invention. Many other changes and modifications made without departing from the concept and scope of the present invention should be considered within the scope of protection of the present invention.

[0030] In the description of this specification, specific features, structures, materials, or characteristics may be combined in any suitable manner in one or more embodiments or examples.

[0031] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A method for online drying of a hot blast stove, characterized in that: The hot blast stoves include two or more existing hot blast stoves and one newly built hot blast stove; each hot blast stove is equipped with a blast furnace cold air duct, a hot combustion air duct, a blast furnace hot blast duct, a gas duct, a pressure exhaust gas duct, a flue gas duct, and a burner; Among them, the hot air pipeline of the in-use hot blast stove is connected to the hot air pipeline of the newly built hot blast stove through a pipeline; the hot blast pipeline of the in-use hot blast stove and the hot blast pipeline of the blast furnace are respectively connected to the hot blast pipeline of the newly built hot blast stove through pipelines. The method includes: 1) The hot combustion air of the existing hot blast stove is supplied to the newly built hot blast stove through pipelines after preheating, so as to perform low-temperature baking of the new hot blast stove; 2) The hot blast pipeline of the existing hot blast stove supplies hot blast to the newly built hot blast stove through the pipeline to carry out the heating section baking of the new hot blast stove; 3) Finally, the furnace is heated in a high-temperature section using the burner on the hot blast stove.

2. The online drying method for a hot blast stove according to claim 1, characterized in that: The temperature range of the low-temperature drying oven is from room temperature to about 200°C, and the heating rate is 1~1.5°C / h.

3. The online drying method for a hot blast stove according to claim 1, characterized in that: The temperature range of the heating section oven is from about 200°C to about 900°C, and the heating rate is 1~4.5°C / h.

4. The online drying method for a hot blast stove according to claim 1, characterized in that: The temperature range of the high-temperature section oven is from about 900°C to about 1200°C, and the heating rate is 12~13°C / h.

5. The online baking method for a hot blast stove according to claim 1, characterized in that: The newly built hot blast stove is also equipped with a pressure relief pipe and a flue gas pipe; a pressure relief valve is installed on the pressure relief pipe, and a flue gas valve is installed on the flue gas pipe. When baking the furnace in the low-temperature section and the heating section, close the flue valve and open the pressure relief valve. The exhaust gas is discharged through the pressure relief pipe. When baking the furnace at high temperature, close the pressure relief valve and open the flue valve, and the exhaust gas is discharged through the flue gas duct.

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