Environment-friendly dust-free damping-down method for blast furnace

Abstract

The invention provides an environment-friendly dust-free damping-down method for a blast furnace, which belongs to the technical field of iron-making blast furnaces, and comprises the following steps: reducing the coal quantity by 50% 4 hours in advance, discharging clean slag iron, reducing air and stopping coal at the same time; when the top pressure is reduced to 15kpa, a clean gas blow-off valve is opened, a gravitational dust removal intercepting valve is closed, two blow-off valves of an ascending pipe are opened, the air volume is reduced to zero, damping down is finished, and in the whole damping down process, the problem that black smoke is emitted when the blow-off valves are opened is remarkably solved, and the air quality is effectively protected.

Description

Technical Field

[0001] The invention belongs to the technical field of iron-making blast furnaces, and in particular relates to an environmentally friendly dust-free blast furnace wind-off method. Background Art

[0002] In the blast furnace ironmaking process, when equipment fails, it needs to be shut down for maintenance, which is an inevitable operation link. Traditional shut-down methods are often accompanied by the emission of a large amount of smoke and dust, which has a serious impact on the environment, especially the black smoke emitted when the vent valve is opened. Therefore, it is of great significance for the ironmaking industry to develop an environmentally friendly dust-free shut-down method that can reduce smoke and dust emissions and protect air quality. Summary of the invention

[0003] The invention provides an environmentally friendly dust-free blast furnace wind-off method to solve the problem of black smoke when a vent valve is opened during the wind-off process.

[0004] In order to solve the above technical problems, the present invention provides a method for environmentally friendly dust-free blast furnace wind stop, which comprises the following steps in sequence:

[0005] S1. N hours before the planned wind-off time, the amount of coal injected is reduced by 50%;

[0006] S2. After the slag and iron are completely discharged and the iron mouth is blown, the air is reduced, and the coal and oxygen are stopped. The material is fed manually. When the air volume is lower than 70% of the normal air volume, the mixed air cut-off valve and the mixed air regulating valve are closed;

[0007] S3. Reduce the air flow in the fan room and reduce the top pressure accordingly. Each time the air flow is reduced, the air flow to the taphole must be guaranteed. When the air pressure is reduced to 100KPa, steam is passed through the furnace top. The furnace top pressure regulation is switched from TRT control to pressure regulating valve group control. At the same time, prepare to cut off the gas.

[0008] S4. When the wind pressure drops to about 50KPa, fully open the pressure regulating valve group. When the top pressure drops to 15KPa, cut off the gas. First open the clean gas release valve, close the gas main butterfly valve, and when the top pressure drops below 10kPa, open the furnace top release valve and drop the gravity shut-off valve.

[0009] S5. After the gas is cut off, gradually release the air and observe the working condition of the tuyere. When the air pressure reaches 15KPa and there is no abnormal iron blockage at the tuyere and the coke at the tuyere does not move, fully open the release valve and observe the working condition of the tuyere again. After confirming that the coke at the tuyere does not move, stop the hot blast furnace and the coal injection.

[0010] S6. After the wind-off process is completed, the wind-off time is reported, the molten iron tank is removed, and the wind-off is completed.

[0011] Compared with the related art, the present invention has the following beneficial effects:

[0012] It can significantly reduce smoke emissions during the wind-down process and effectively improve air quality; the method is simple to operate and easy to implement, suitable for various types of blast furnace equipment, and has broad application prospects; it reduces the erosion of smoke on blast furnace equipment and extends the service life of the equipment; it reduces the cost of environmental protection management and improves the economic benefits of iron-making enterprises. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] The drawings constituting part of the present application are used to provide a further understanding of the present application. The exemplary embodiments and descriptions of the present application are used to explain the present application and do not constitute an improper limitation on the present application. Among them:

[0014] Figure 1 A flow chart of the method for environmentally friendly dust-free wind-down of a blast furnace provided by the present invention. DETAILED DESCRIPTION

[0015] The present application will be described in detail below with reference to the accompanying drawings and in conjunction with embodiments. Each example is provided by way of explanation of the present application and does not limit the present application. In fact, it will be clear to those skilled in the art that modifications and variations may be made in the present application without departing from the scope or spirit of the present application. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the present application embodiments should fall within the scope of protection of the present application embodiments.

[0016] Example

[0017] Please refer to Figure 1 This embodiment provides a method for environmentally friendly dust-free blast furnace ventilation, the method comprising the following steps in sequence:

[0018] S1. Four hours before the planned wind-off time, notify the coal injection operation area to reduce the amount of coal injection by 50%;

[0019] S2. After the slag and iron are completely discharged and the iron mouth is blown, notify the dispatcher and TRT to start reducing the air flow, stop the coal and oxygen, and manually feed the material. When the air volume is lower than 70% of the normal air volume, close the mixed air cut-off valve and the mixed air regulating valve;

[0020] S3. Reduce the air flow in the fan room and remove the top pressure accordingly (i.e., high pressure to normal pressure operation). Each time the air flow is reduced, the iron mouth must be guaranteed to have air. When the air pressure is reduced to 100KPa, steam is passed through the furnace top (the top steam must be closed in advance before the furnace top is ignited). The furnace top pressure regulation is switched from TRT control to pressure regulating valve group control, and gas is prepared to be cut off at the same time.

[0021] S4. When the wind pressure drops to about 50KPa, fully open the pressure regulating valve group. When the top pressure drops to 15KPa, cut off the gas. First open the clean gas release valve, close the gas main butterfly valve, and when the top pressure drops below 10kPa, open the furnace top release valve and drop the gravity shut-off valve.

[0022] S5. After the gas is cut off, gradually release the air and observe the working condition of the tuyere. When the air pressure reaches 15KPa and there is no abnormal iron blockage at the tuyere and the coke at the tuyere does not move, fully open the release valve and observe the working condition of the tuyere again. After confirming that the coke at the tuyere does not move, stop the hot blast furnace and the coal injection.

[0023] S6. After the wind-off process is completed, the wind-off time is reported, the molten iron tank is removed, and the wind-off is completed.

[0024] The wind-off method of this embodiment can significantly reduce smoke and dust emissions during the wind-off process and effectively improve air quality; the method is simple to operate and easy to implement, is applicable to various types of blast furnace equipment, and has broad application prospects; it reduces the erosion of smoke and dust on blast furnace equipment and extends the service life of the equipment; it reduces environmental protection management costs and improves the economic benefits of ironmaking enterprises.

[0025] The above description is only a preferred embodiment of the present application and is not intended to limit the present application. For those skilled in the art, the present application may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A method for environmentally friendly dust-free blast furnace air shut-off, characterized in that: The method comprises the following steps in sequence: S1. N hours before the planned wind-off time, the amount of coal injected is reduced by 50%; S2. After the slag and iron are completely discharged and the iron mouth is blown, the air is reduced, and the coal and oxygen are stopped. The material is fed manually. When the air volume is lower than 70% of the normal air volume, the mixed air cut-off valve and the mixed air regulating valve are closed; S3. Reduce the air flow in the fan room and reduce the top pressure accordingly. Each time the air flow is reduced, the air flow to the taphole must be guaranteed. When the air pressure is reduced to 100KPa, steam is passed through the furnace top. The furnace top pressure regulation is switched from TRT control to pressure regulating valve group control. At the same time, prepare to cut off the gas. S4. When the wind pressure drops to about 50KPa, fully open the pressure regulating valve group. When the top pressure drops to 15KPa, cut off the gas. First open the clean gas release valve, close the gas main butterfly valve, and when the top pressure drops below 10kPa, open the furnace top release valve and drop the gravity shut-off valve. S5. After the gas is cut, gradually release the air and observe the working condition of the tuyere. When the air pressure reaches 15KPa, there is no abnormal iron blockage at the tuyere. After the coke at the tuyere does not move, fully open the release valve and observe the working condition of the tuyere again. After confirming that the coke at the tuyere does not move, stop the hot blast furnace and the coal injection. S6. After the wind-off process is completed, the wind-off time is reported, the molten iron tank is removed, and the wind-off is completed.

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