A method for controlling blast furnace air volume to stabilize furnace conditions

Abstract

The present application relates to the field of blast furnace operation control, a method for controlling blast furnace air volume to stabilize furnace condition, comprising the following steps: step one, collecting the average value ΔP of the total pressure difference of the blast furnace in the last 24 hours, then setting the blast furnace control pressure difference as ΔP+15kPa; if ΔP+15kPa≥200kPa, then setting the blast furnace control pressure difference as 200±5kPa; step two, when the instantaneous pressure difference in the furnace reaches the set control pressure difference, if the air flow is unstable, which is manifested as the 25m static pressure difference bifurcation being greater than 25kPa or the 29m static pressure difference being greater than 10kPa, the foreman directly controls the air volume to be 100-200Nm 3 / min; if the air flow is stable, i.e. the 25m static pressure difference is less than 25kPa and the 29m static pressure difference is less than 10kPa, the air volume can be temporarily maintained; step three, when the pressure difference in 2-5min is greater than the set control pressure difference, an alarm is given and the air volume is controlled to be 100-300Nm 3 / min. After using the improved blast furnace air volume control method, the stability and smoothness of the 6# blast furnace condition are improved, the foreman's prediction of the blast furnace condition change is effectively guided, the number of air volume increase and decrease is reduced, and the furnace condition can be stabilized for a long period.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of blast furnace operation control, in particular to a method for controlling blast furnace air volume to stabilize furnace condition. BACKGROUND

[0002] The blast furnace air volume is an important index of the blast furnace operation state, which refers to the volume of the air entering the blast furnace per unit time under standard state. The blast furnace air volume is first determined by the blast furnace volume. Under the same conditions, the greater the air volume, the higher the output. Under normal production, the air volume entering the blast furnace is required to be stable. Only when the blast furnace is cooled, the material is not discharged smoothly, or the equipment fails and needs to be treated by reducing the air volume, the air volume is reduced. Once the conditions allow the air volume to be restored, it should be timely and gradually restored.

[0003] Under daily production, the foreman generally controls the air volume through the instantaneous pressure difference. If the blast furnace frequently increases and reduces the air volume, the air volume fluctuation will affect the material speed and the furnace temperature fluctuation, which will further affect the stability and smooth operation of the blast furnace. Therefore, how to reasonably control the air volume to keep the blast furnace airflow stable has become an important issue to be solved in blast furnace production.

[0004] The present application is developed under such circumstances. The operation characteristics of the blast furnace under normal production conditions are that the blast furnace is stable in air volume and output under certain raw fuel conditions. When the instantaneous pressure difference exceeds the set upper limit, the air volume should be controlled in time, otherwise long-term high pressure difference operation will lead to abnormal blast furnace airflow. The traditional operation is mainly based on experience, and there are many human factors. The operation level of the foreman affects the stability and smooth operation of the blast furnace. If the instantaneous pressure difference reaches the control standard, the air volume will be reduced, which will lead to frequent increase and reduction of the blast furnace air volume. In view of this phenomenon existing in the blast furnace production, the present application proposes an improved blast furnace air volume control method to reduce the frequent increase and reduction of the air volume, reduce the fluctuation of the furnace condition, and maintain a high level of output and index. SUMMARY

[0005] The purpose of the present application is to provide a method for controlling the blast furnace air volume to stabilize the furnace condition.

[0006] The purpose of the present application is achieved by a method for controlling the blast furnace air volume to stabilize the furnace condition, comprising the following steps: step one, collecting the average value ΔP of the total pressure difference of the blast furnace in the last 24 hours, and setting the blast furnace control pressure difference as ΔP+15kPa; if ΔP+15kPa≥200kPa, the blast furnace control pressure difference is set as 200±5 kPa; step two, when the instantaneous pressure difference in the furnace reaches the set control pressure difference, if the airflow is unstable, which is manifested as that the 25m static pressure difference is greater than 25kPa or the 29m static pressure difference is greater than 10kPa, the foreman directly controls the air volume to be 100-200Nm 3 / min; if the air flow is stable, i.e. the 25m static pressure difference is less than 25kPa and the 29m static pressure difference is less than 10kPa, the air flow can be temporarily maintained; in step three, when the 2-5min pressure difference is greater than the set control pressure difference, an alarm is given and the air flow is controlled to be 100-300Nm 3 / min.

[0007] The beneficial effects of the present application are that after using the improved blast furnace air flow control method, the stability and smoothness of the 6# blast furnace condition are improved, the forejudgment of the foreman to the blast furnace condition change is effectively guided, the number of air flow increase and decrease is reduced, and the blast furnace condition is stably maintained for a long period. The blast furnace fluctuation frequency and loss are reduced, and the important economic and technical indicators are obviously improved, which achieves great benefits. The main benefits are as follows: the daily output of molten iron of the 6# blast furnace of TISCO is increased from 9571t / d to 9903t / d, and according to the normal production and operation of the steel enterprise, the economic benefit brought to the enterprise by each ton of molten iron is at least 200yuan / tFe. The economic benefit generated per year after the output is increased: (9903-9571) x 360 x 200 / 10000 x 40% = 956.2 million yuan.

[0008] Therefore, the economic benefit generated by the present application per year is 956.2 million yuan, which not only has good economic benefit, but also has high popularization value.

[0009] Note: The data time range after using the patent is from October 2020 to September 2022, and the comparison data time range is from the blowing-in of the 6# blast furnace to September 2020. DETAILED DESCRIPTION

[0010] In daily blast furnace operation, the air flow should be stably maintained within a certain range, and frequent increase and decrease of air flow should be avoided to stabilize the furnace condition. In traditional operation, if the instantaneous pressure difference reaches the control standard, the air flow will be reduced, which will affect the stable and smooth operation of the blast furnace. How to reduce the number of frequent increase and decrease of air flow and stabilize the furnace condition is an important problem to be solved in blast furnace production. The present application proposes a method for controlling the air flow of the blast furnace to stabilize the furnace condition, which mainly uses the full pressure difference, the 25m and 29m static pressure difference bifurcation level, and the 2-5min pressure difference to control the air flow, so as to control the air flow and avoid the fluctuation of the furnace condition caused by frequent reduction of the air flow. The present application uses data operation to avoid experience operation, which can effectively reduce the number of air flow reduction, is beneficial to the long-period stable and smooth operation of the blast furnace, and achieves good results.

[0011] 1. Controlling the air flow of the blast furnace according to the pressure difference data

[0012] According to the fluctuation level of the pressure difference, i.e. the difference between the hot blast pressure and the top pressure in the blast furnace iron-making production, the pressure difference can be controlled and stabilized by adjusting the air volume, air temperature and coke ratio. The traditional judgment method mainly relies on the full pressure difference of the blast furnace column and the descent of the column size, and basically analyzes the starting conditions and results. Sometimes, when the pipeline appears, the pressure difference is very low. Therefore, we propose a certain time range of moving pressure difference operation method. According to the production experience, the moving pressure difference of 2-5 minutes is generally taken, i.e. the average value of the pressure difference of 2-5 minutes before the current time. When the moving pressure difference is greater than the upper limit of the pressure difference set according to the production conditions, the air flow must be controlled.

[0013] 2. Control the air volume according to the size of the static pressure difference of 25m and 29m

[0014] The static pressure can make up for the defects and deficiencies of the full pressure difference air reduction operation. Sometimes, the static pressure difference can clearly show that the blast furnace has a serious problem, but it is not obvious from the full pressure difference.

[0015] The static pressure can facilitate the foreman to directly monitor the pressure conditions at different positions of the longitudinal edge of the blast furnace, more forwardly judge the local air flow in the blast furnace, and guide the foreman to adjust in advance.

[0016] In the operation, the numerical range of the static pressure at different heights is monitored in real time to judge whether the air flow distribution of the blast furnace is normal and reasonable. According to the operation experience, the static pressure difference and the blast furnace condition in the secondary database are analyzed. If the static pressure difference of 25m is greater than 25kPa or the static pressure difference of 29m is greater than 10kPa, it indicates that the air flow of the blast furnace is abnormal, the deviation is large, the air flow is unevenly distributed, the blast furnace operation type changes, and the edge air flow is easy to upsurge. Therefore, the air volume needs to be controlled in time to prevent the blast furnace from appearing the pipeline.

[0017] The present application proposes a new method for controlling the air volume of the blast furnace to stabilize the blast furnace condition, which mainly uses the full pressure difference of the blast furnace, the static pressure difference of 25m and 29m, and the 2-5min moving pressure difference to control the air volume. The method comprises the following steps: step one, collecting the average value ΔP of the full pressure difference of the blast furnace in the last 24 hours, and setting the control pressure difference of the blast furnace as ΔP+15kPa; if ΔP+15≥200, the control pressure difference of the blast furnace is set as 200kPa; step two, when the instantaneous pressure difference in the blast furnace reaches the set control pressure difference, if the air flow is unstable, which is manifested as that the static pressure difference of 25m is greater than 25kPa or the static pressure difference of 29m is greater than 10kPa, the foreman directly controls the air volume; if the air flow is stable, i.e. the static pressure difference of 25m is less than 25kPa and the static pressure difference of 29m is less than 10kPa, the air volume can be temporarily not reduced; step three, when the 2-5min moving pressure difference is greater than the set control pressure difference, the first level system pops up an alarm, and the foreman controls the air volume to control the air flow and avoid the effect of frequent air reduction leading to the fluctuation of the blast furnace condition.

[0018] The improved air volume control method has been used in TISCO 6# blast furnace in April 2021, and the implementation examples are as follows: if the instantaneous pressure difference in the furnace reaches the set control pressure difference, the airflow is unstable, which is manifested as that the 25m static pressure difference is greater than 25kpa or the 29m static pressure difference is greater than 10kPa, and the foreman directly controls the air volume; when the instantaneous pressure difference in the furnace reaches the set control pressure difference, if the airflow is stable, such as the heat load is stable, the 25m static pressure difference is less than 10kPa, the air volume can be not reduced first, and the 3min pressure difference is observed; if the 3min pressure difference reaches the set control pressure difference, the air volume must be reduced to control the airflow.

[0019] On April 13, 2021, at 9:00 in the morning shift, when the instantaneous pressure difference in the furnace of TISCO 6# blast furnace reaches the set control pressure difference 190kpa, the airflow is unstable, the 25m static pressure difference is 31kpa, and the 29m static pressure difference is 13kPa, and the foreman directly controls the air volume 200Nm 3 / min; when the subsequent 3min pressure difference reaches the set control pressure difference 190kpa, the blast furnace continues to reduce the air volume 100Nm 3 / min. After using the above operation method, the airflow of the blast furnace is not continuously deteriorated, the furnace condition is gradually stabilized, and after the pressure difference and the static pressure are restored to the normal stable state, the air volume of the blast furnace is gradually restored.

[0020] The above only describes specific embodiments of the present application, but the structural features of the scope of protection of the present application are not limited thereto, any person skilled in the art makes changes or modifications in the field of the present application, which are covered in the patent scope of the present application.

Claims

1. A method of controlling blast volume for stabilizing the condition of a blast furnace, characterized by: Comprising the following steps: Step one, collect the average value of the blast furnace differential pressure in the last 24 hours ΔP, then set the blast furnace control pressure difference as ΔP+15kPa; if ΔP+15kPa≥200kPa, then set the blast furnace control pressure difference as 200±5 kPa; Step two, when the instantaneous pressure difference in the furnace reaches the set control pressure difference, if the gas flow is unstable, which is manifested by the 25m static pressure difference bifurcation being greater than 25kPa or the 29m static pressure difference being greater than 10kPa, the foreman directly controls the air volume to be 100-200Nm / min; if the gas flow is stable, i.e. the 25m static pressure difference is less than 25kPa and the 29m static pressure difference is less than 10kPa, the air volume is temporarily maintained. 3 Step two, when the instantaneous pressure difference in the furnace reaches the set control pressure difference, if the gas flow is unstable, which is manifested by the 25m static pressure difference bifurcation being greater than 25kPa or the 29m static pressure difference being greater than 10kPa, the foreman directly controls the air volume to be 100-200Nm / min; if the gas flow is stable, i.e. the Step three, when 2 ~ 5min pressure difference greater than the set control pressure difference, then alarm, control air volume 100-300Nm 3 / min.