Method for cooling silica brick hot blast stove of blast furnace

Abstract

The invention discloses a blast furnace silica brick hot blast stove cooling method which comprises the following steps: (1) firstly, the hot blast stove does not burn, in the initial cooling stage, a hot blast stove combustion fan is adopted to cool the stove, the vault temperature is slowly reduced to 900 DEG C from 1200 DEG C at a first cooling rate, and the exhaust gas temperature is controlled not to exceed 400 DEG C; (2) using a blast furnace blower as an air source to increase the air volume, continuing to cool the furnace, and slowly cooling the vault temperature from 900 DEG C to 700 DEG C at a second cooling rate; and (3) increasing the air volume and the air pressure of the blast furnace blower, continuously cooling the furnace, and slowly cooling the vault temperature from 700 DEG C to 120 DEG C at a third cooling rate. According to the method, slow cooling of the hot blast stove is achieved through three stages, damage to silica brick masonry caused by too fast cooling is avoided, and therefore the service life of the hot blast stove is prolonged.

Description

Technical Field

[0001] The invention relates to the technical field of blast furnace production, and in particular to a method for cooling a blast furnace silicon brick hot blast furnace. Background Art

[0002] The high temperature zone of the blast furnace hot blast stove is made of siliceous material. Due to the lattice transformation of residual quartz in the low temperature zone of silica bricks, volume changes will occur and its expansion coefficient is large. If the temperature is reduced too quickly, the silica brick masonry will be damaged. Therefore, the cooling of the silica brick hot blast stove is the same as the baking stove. There will also be risks if improper operation occurs during the process. If the hot blast stove is not cooled reasonably, the masonry will be easily damaged, thus affecting the service life of the hot blast stove. Therefore, strict requirements must be imposed on the cooling of the hot blast stove from the formulation of the curve to the control of the cooling rate.

[0003] The cooling furnace uses the dome temperature as its main control temperature, and the regenerator silica brick interface temperature and grate temperature as monitoring temperatures. When using combustion air to cool down in the initial stage, the grate temperature should be ensured not to exceed the maximum working temperature, that is, the grate RQTSi4Mo material is required not to exceed 470℃, and the RTCR2 material is required not to exceed 420℃. Therefore, how to avoid the damage of silica brick masonry due to excessive cooling has become a problem that needs to be solved urgently. Summary of the invention

[0004] The technical problem to be solved by the present invention is to provide a method for cooling a blast furnace silicon brick hot blast furnace, which adopts three stages to achieve slow cooling of the hot blast furnace, thereby avoiding damage to the silicon brick masonry due to too fast cooling, thereby increasing the service life of the hot blast furnace.

[0005] In order to solve the above technical problems, the present invention adopts the following technical solution: A method for cooling a blast furnace silicon brick hot blast furnace of the present invention, the innovation of which is that it comprises the following steps: (1) First, the hot blast furnace is no longer fired, and in the initial stage of cooling, the hot blast furnace combustion fan is used to cool the furnace, and the dome temperature is slowly cooled from 1200℃ to 900℃ at the first cooling rate, and the exhaust gas temperature is controlled not to exceed 400℃; (2) Then, the blast furnace blower is used as the air source to increase the air volume, and the furnace is cooled down continuously, and the dome temperature is slowly cooled down from 900°C to 700°C at the second cooling rate; (3) Then increase the air volume and pressure of the blast furnace blower, continue to cool the furnace, and slowly cool the dome temperature from 700°C to 120°C at the third cooling rate.

[0006] Preferably, in the above step (1), the specific process of cooling the dome temperature from 1200° C. to 900° C. is as follows: (1.1) First start the combustion-supporting fan and adjust the air pressure to 7.5kpa; (1.2) Open the air regulating valve and adjust its opening to 80%; at the same time, fully open the air shut-off valve and the flue valve; (1.3) At this time, the high-temperature exhaust gas is discharged through the chimney by the combustion-supporting fan, and then the first stage of cooling the furnace is slowly carried out at the first cooling rate of 6.3℃ / h. After cooling for 2 days, the dome temperature is slowly cooled from 1200℃ to 900℃.

[0007] Preferably, if the exhaust gas temperature exceeds 400°C, the flue valve opening should be adjusted to 50% depending on the rising trend of the exhaust gas temperature, and the air control valve opening should be adjusted to 30% at the same time, thereby reducing the immediate discharge of a large amount of high-temperature exhaust gas and avoiding damage to equipment and refractory materials due to improper furnace cooling.

[0008] Preferably, in the above step (2), the specific process of cooling the dome temperature from 900° C. to 700° C. is as follows: (2.1) Start the blast furnace blower, control the blower air volume and pressure according to the second cooling rate, and control the blast furnace blower pressure at 200~300kPa; (2.2) Fully open the backflow valve to ensure smooth heat dissipation; (2.3) Open the air-cooled equalizing pressure valve, adjust the air intake volume by adjusting the opening of the air-cooled equalizing pressure valve, and then adjust the second cooling rate to 2.8℃ / h; (2.4) The high-temperature exhaust gas is passed through the grate, the regenerator checker bricks, and the hot blast furnace vault in sequence at a second cooling rate of 2.8°C / h to enter the hot blast outlet. The hot blast valve is then opened to allow the high-temperature exhaust gas to enter the hot blast main pipe and then discharged into the atmosphere through the backflow valve, thereby slowly cooling the furnace in the second stage. (2.5) After cooling for 3 days, slowly cool the dome temperature from 900℃ to 700℃.

[0009] Preferably, in the above step (3), the specific process of cooling the dome temperature from 700°C to 120°C is as follows: (3.1) First, increase the air volume and pressure of the blast furnace blower, and control the pressure of the blast furnace blower at 300~400kpa; (3.2) Then fully open the cold air valve, and then adjust the opening of the cold air valve according to the vault temperature, and let the high-temperature exhaust gas enter the hot air outlet through the grate, the heat storage chamber lattice bricks, and the hot air furnace vault in turn. Then open the hot air valve to allow the high-temperature exhaust gas to enter the hot air main pipe, and then be discharged into the atmosphere through the backflow valve, and then slowly carry out the third stage of cooling the furnace at the third cooling rate.

[0010] Preferably, in the above step (3.2), the third cooling rate is adjusted by adjusting the opening of the cold air valve, and the third cooling rate is set in three cases, specifically: (3.2.1) During the process of the dome temperature decreasing from 700°C to 580°C, the third cooling rate is adjusted to 1.7°C / h, and the cooling time of this process is 3 days; (3.2.2) During the process of the dome temperature decreasing from 580°C to 300°C, the third cooling rate is adjusted to 1.6°C / h, and the cooling time of this process is 7 days; (3.2.3) During the process of the dome temperature decreasing from 300°C to 120°C, the third cooling rate was adjusted to 1.3°C / h, and the cooling time of this process was 6 days.

[0011] Preferably, in the above step (3.2), the cold air valve is initially in a fully open state, and when the temperature rises too quickly, the opening of the cold air valve needs to be adjusted to 30%-50%.

[0012] Preferably, when the dome temperature drops to 120° C., it is regarded as the end point of the cooling.

[0013] Preferably, the dome temperature is used as the vertical axis, the cooling time is used as the horizontal axis, and the first cooling rate, the second cooling rate and the third cooling rate are used as the slopes of each stage, thereby forming a cooling curve for the hot blast furnace to cool down, and ensuring that the cooling is strictly carried out according to the cooling curve during the cooling period; in the process of cooling down according to the cooling curve, if the difference between the temperature change of the interface between the silica brick and the high-alumina brick and the dome temperature is too large, it is necessary to reduce the cooling speed of the hot blast furnace and increase the cooling time.

[0014] Preferably, during the process of cooling down the furnace, a slight positive pressure of 1 kPa is maintained in the hot blast furnace, thereby preventing air other than that provided by the combustion-supporting blower from entering, which makes the total air flow in the hot blast furnace difficult to control.

[0015] Beneficial effects of the present invention: The present invention uses three stages to achieve slow cooling of the hot blast furnace, thereby avoiding damage to the silicon brick masonry due to excessively rapid cooling, thereby increasing the service life of the hot blast furnace. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0017] Figure 1 The present invention is a schematic diagram of a method for cooling a blast furnace silicon brick hot blast furnace.

[0018] Figure 2 It is a schematic diagram of a cooling curve of the present invention. DETAILED DESCRIPTION

[0019] The technical solution of the present invention will be clearly and completely described below through specific implementation methods.

[0020] A method for cooling a blast furnace silicon brick hot blast furnace of the present invention, as follows Figure 1 , Figure 2 As shown, the following steps are included: (1) First, the hot blast furnace is no longer burned, and in the initial stage of cooling, the hot blast furnace combustion fan is used to cool the furnace, and the dome temperature is slowly cooled from 1200℃ to 900℃ at the first cooling rate, and the exhaust gas temperature is controlled not to exceed 400℃.

[0021] In the above steps, the specific process of cooling the dome temperature from 1200°C to 900°C is as follows: (1.1) First start the combustion-supporting fan and adjust the air pressure to 7.5 kPa.

[0022] (1.2) Open the air regulating valve and adjust its opening to 80%; at the same time, fully open the air shut-off valve and the flue valve.

[0023] (1.3) At this time, the high-temperature exhaust gas is discharged through the chimney by the combustion-supporting fan, and then the first stage of cooling the furnace is slowly carried out at the first cooling rate of 6.3℃ / h. After cooling for 2 days, the dome temperature is slowly cooled from 1200℃ to 900℃.

[0024] If the exhaust gas temperature exceeds 400°C, the flue valve opening must be adjusted to 50% depending on the rising trend of the exhaust gas temperature, and the air control valve opening must be adjusted to 30% at the same time, thereby reducing the immediate discharge of a large amount of high-temperature exhaust gas and avoiding damage to equipment and refractory materials due to improper furnace cooling.

[0025] (2) Then, the blast furnace blower is used as the air source to increase the air volume, and the furnace is cooled down continuously, and the dome temperature is slowly cooled down from 900°C to 700°C at the second cooling rate.

[0026] In the above steps, due to the limited capacity of the combustion-supporting fan, it is far from enough to meet the requirements of cooling air volume and pressure. Therefore, when the temperature drops to 900℃, the blast furnace blower is used as the wind source to increase the air volume. The specific process of cooling the dome temperature from 900℃ to 700℃ is as follows: (2.1) Start the blast furnace blower, control the blower air volume and pressure according to the second cooling rate, and control the blast furnace blower pressure at 200~300kPa.

[0027] (2.2) Fully open the backflow valve to ensure smooth heat dissipation.

[0028] (2.3) Open the air-cooled equalizing pressure valve, adjust the air intake volume by adjusting the opening of the air-cooled equalizing pressure valve, and then adjust the second cooling rate to 2.8℃ / h.

[0029] (2.4) At the second cooling rate of 2.8℃ / h, the high-temperature exhaust gas is passed through the grate, the lattice bricks of the heat storage chamber, and the dome of the hot blast furnace into the hot blast outlet. Then the hot blast valve is opened to allow the high-temperature exhaust gas to enter the hot blast main pipe and then be discharged into the atmosphere through the backflow valve, thereby slowly cooling the furnace in the second stage.

[0030] (2.5) After cooling for 3 days, slowly cool the dome temperature from 900℃ to 700℃.

[0031] Because this temperature is the crystallization transformation process of siliceous bricks, if the temperature drops too quickly, it will cause the bricks to be damaged, so the cooling in this process is mainly slow and not too fast.

[0032] (3) Then increase the air volume and pressure of the blast furnace blower, continue to cool the furnace, and slowly cool the dome temperature from 700°C to 120°C at the third cooling rate.

[0033] In the above steps, the specific process of cooling the dome temperature from 700°C to 120°C is as follows: (3.1) First, increase the air volume and pressure of the blast furnace blower, and control the pressure of the blast furnace blower at 300~400kpa.

[0034] (3.2) Then fully open the cold air valve, and then adjust the opening of the cold air valve according to the vault temperature, and let the high-temperature exhaust gas enter the hot air outlet through the grate, the heat storage chamber lattice bricks, and the hot air furnace vault in turn. Then open the hot air valve to allow the high-temperature exhaust gas to enter the hot air main pipe, and then be discharged into the atmosphere through the backflow valve, and then slowly carry out the third stage of cooling the furnace at the third cooling rate.

[0035] The third cooling rate is adjusted by adjusting the opening of the cold air valve, and the third cooling rate is set in three situations, specifically: (3.2.1) During the process of cooling the dome temperature from 700°C to 580°C, the third cooling rate was adjusted to 1.7°C / h, and the cooling time of this process was 3 days.

[0036] (3.2.2) During the process of the dome temperature decreasing from 580°C to 300°C, the third cooling rate was adjusted to 1.6°C / h, and the cooling time of this process was 7 days.

[0037] (3.2.3) During the process of the dome temperature decreasing from 300°C to 120°C, the third cooling rate was adjusted to 1.3°C / h, and the cooling time of this process was 6 days.

[0038] The cold air valve of the present invention is initially in a fully open state, and when the temperature rises too quickly, the opening of the cold air valve needs to be adjusted to 30%-50%; when the dome temperature drops to 120°C, it is regarded as the end point of the cooling.

[0039] The present invention takes the dome temperature as the vertical axis, the cooling time as the horizontal axis, and the first cooling rate, the second cooling rate, and the third cooling rate as the slope of each stage, thereby forming a cooling curve of the hot blast furnace cooling furnace, such as Figure 2 As shown, ensure that the cooling is carried out strictly according to the cooling curve during the cooling process; during the cooling process according to the cooling curve, if the difference between the temperature change of the interface between the silica brick and the high alumina brick and the dome temperature is too large, it is necessary to reduce the cooling speed of the hot blast furnace and increase the cooling time.

[0040] In the process of cooling down the furnace, the hot blast furnace is required to maintain a small positive pressure of 1 kPa, thereby preventing air other than that provided by the combustion-supporting blower from entering, resulting in the difficulty in controlling the total air flow in the hot blast furnace.

[0041] Beneficial effects of the present invention: The present invention uses three stages to achieve slow cooling of the hot blast furnace, thereby avoiding damage to the silicon brick masonry due to excessively rapid cooling, thereby increasing the service life of the hot blast furnace.

[0042] The embodiments described above are merely descriptions of preferred implementation modes of the present invention, and are not intended to limit the concept and scope of the present invention. Without departing from the design concept of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary engineering technicians in the field should fall within the protection scope of the present invention. The technical contents for which protection is sought in the present invention have been fully recorded in the technical requirements.

Claims

1. A method for cooling a blast furnace silicon brick hot blast furnace, characterized in that The following steps are involved: (1) First, the hot blast furnace is no longer fired, and in the initial stage of cooling, the hot blast furnace combustion fan is used to cool the furnace, and the dome temperature is slowly cooled from 1200℃ to 900℃ at the first cooling rate, and the exhaust gas temperature is controlled not to exceed 400℃; (2) Then, the blast furnace blower is used as the air source to increase the air volume, and the furnace is cooled down continuously, and the dome temperature is slowly cooled down from 900°C to 700°C at the second cooling rate; (3) Then increase the air volume and pressure of the blast furnace blower, continue to cool the furnace, and slowly cool the dome temperature from 700°C to 120°C at the third cooling rate.

2. The method for cooling a blast furnace silicon brick hot blast furnace according to claim 1, characterized in that: In the above step (1), the specific process of cooling the dome temperature from 1200°C to 900°C is as follows: (1.1) First start the combustion-supporting fan and adjust the air pressure to 7.5kpa; (1.2) Open the air regulating valve and adjust its opening to 80%; at the same time, fully open the air shut-off valve and the flue valve; (1.3) At this time, the high-temperature exhaust gas is discharged through the chimney by the combustion-supporting fan, and then the first stage of cooling the furnace is slowly carried out at the first cooling rate of 6.3℃ / h. After cooling for 2 days, the dome temperature is slowly cooled from 1200℃ to 900℃.

3. The method for cooling a blast furnace silicon brick hot blast furnace according to claim 2, characterized in that: If the exhaust gas temperature exceeds 400℃, the flue valve opening must be adjusted to 50% depending on the rising trend of the exhaust gas temperature, and the air control valve opening must be adjusted to 30% at the same time, thereby reducing the immediate discharge of a large amount of high-temperature exhaust gas and avoiding damage to equipment and refractory materials due to improper furnace cooling.

4. The method for cooling a blast furnace silicon brick hot blast furnace according to claim 1, characterized in that: In the above step (2), the specific process of cooling the dome temperature from 900°C to 700°C is as follows: (2.1) Start the blast furnace blower, control the blower air volume and pressure according to the second cooling rate, and control the blast furnace blower pressure at 200~300kPa; (2.2) Fully open the backflow valve to ensure smooth heat dissipation; (2.3) Open the air-cooled equalizing pressure valve, adjust the air intake volume by adjusting the opening of the air-cooled equalizing pressure valve, and then adjust the second cooling rate to 2.8℃ / h; (2.4) The high-temperature exhaust gas is passed through the grate, the regenerator checker bricks, and the hot blast furnace vault in sequence at a second cooling rate of 2.8°C / h to enter the hot blast outlet. The hot blast valve is then opened to allow the high-temperature exhaust gas to enter the hot blast main pipe and then discharged into the atmosphere through the backflow valve, thereby slowly cooling the furnace in the second stage. (2.5) After cooling for 3 days, slowly cool the dome temperature from 900℃ to 700℃.

5. The method for cooling a blast furnace silicon brick hot blast furnace according to claim 1, characterized in that: In the above step (3), the specific process of cooling the dome temperature from 700°C to 120°C is as follows: (3.1) First, increase the air volume and pressure of the blast furnace blower, and control the pressure of the blast furnace blower at 300~400kpa; (3.2) Then fully open the cold air valve, and then adjust the opening of the cold air valve according to the vault temperature, and let the high-temperature exhaust gas enter the hot air outlet through the grate, the heat storage chamber lattice bricks, and the hot air furnace vault in turn. Then open the hot air valve to allow the high-temperature exhaust gas to enter the hot air main pipe, and then be discharged into the atmosphere through the backflow valve, and then slowly carry out the third stage of cooling the furnace at the third cooling rate.

6. The method for cooling a blast furnace silicon brick hot blast furnace according to claim 5, characterized in that: In the above step (3.2), the third cooling rate is adjusted by adjusting the opening of the cold air valve, and the third cooling rate is set in three cases, specifically: (3.2.1) During the process of the dome temperature decreasing from 700°C to 580°C, the third cooling rate is adjusted to 1.7°C / h, and the cooling time of this process is 3 days; (3.2.2) During the process of the dome temperature decreasing from 580°C to 300°C, the third cooling rate is adjusted to 1.6°C / h, and the cooling time of this process is 7 days; (3.2.3) During the process of cooling the dome temperature from 300°C to 120°C, the third cooling rate was adjusted to 1.3°C / h, and the cooling time of this process was 6 days.

7. The method for cooling a blast furnace silicon brick hot blast furnace according to claim 6, characterized in that: In the above step (3.2), the cold air valve is initially fully open, and when the temperature rises too quickly, the opening of the cold air valve needs to be adjusted to 30%~50%.

8. The method for cooling a blast furnace silicon brick hot blast furnace according to claim 6, characterized in that: When the dome temperature drops to 120℃, it is considered the end of the cooling process.

9. The method for cooling a blast furnace silicon brick hot blast furnace according to claim 6, characterized in that: The dome temperature is taken as the vertical axis, the cooling time is taken as the horizontal axis, and the first cooling rate, the second cooling rate and the third cooling rate are taken as the slopes of each stage, thereby forming a cooling curve for the hot blast furnace. Ensure that the cooling is carried out strictly in accordance with the cooling curve during the cooling period. In the process of cooling down according to the cooling curve, if the difference between the temperature change of the interface between the silica brick and the high-alumina brick and the dome temperature is too large, it is necessary to reduce the cooling speed of the hot blast furnace and increase the cooling time.

10. The method for cooling a blast furnace silicon brick hot blast furnace according to claim 1, characterized in that: During the cooling process, a small positive pressure of 1kpa should be maintained in the hot blast furnace to prevent the entry of air other than that provided by the combustion-supporting fan, which makes the total air flow in the hot blast furnace difficult to control.

Images