Method for judging blowing ignition condition of converter

Abstract

The invention relates to a method for judging the blowing ignition condition of a converter, and belongs to the technical field of steelmaking methods. According to the technical scheme, the method comprises the steps that the oxygen content value of flue gas in a furnace mouth flue is monitored, monitoring and timing are started when a converter sends out a blowing starting signal, whether blowing is started and fire is not ignited or not is judged according to comparison of the oxygen content value of the flue gas in the set time, and after it is judged that the fire is not ignited, normal ignition is guaranteed by reducing the height of an oxygen lance, increasing the oxygen flow and increasing the bottom blowing flow. The method has the beneficial effects that the blowing ignition condition can be quickly and accurately judged by monitoring the oxygen content of the flue gas in the furnace mouth flue, a splashing accident caused by non-ignition during blowing and a blowing stopping accident caused by automatic lifting of a dry dedusting gun are avoided, and the aim of improving the technical and economic indexes and the production efficiency of the converter is achieved.

Description

Technical Field

[0001] The invention relates to a method for judging the ignition condition of a converter and belongs to the technical field of steelmaking methods. Background Art

[0002] The existing methods for judging the ignition situation of the blow-off are as follows: First, steelmakers judge the ignition situation by blowing the flame. The flame can only be clear after the oxygen flow rate climbs to full oxygen in about 90 seconds, and there is no unified standard for manual judgment. Second, the oxygen content monitoring value of the flue gas at the outlet of the electrostatic precipitator of the dry dust removal system is used. The outlet of the electrostatic precipitator of the dry dust removal system is about 400-500m away from the furnace mouth. The flue gas takes 90-120 seconds to reach the monitoring point, which is late. The two existing judgment methods are time-consuming and easy to misjudge, which brings great hidden dangers to the existing operation. In particular, after 90 seconds, the oxidation in the furnace is strong, which is easy to cause splashing production environmental accidents. At the same time, as time goes on, when the carbon-oxygen reaction begins, the carbon monoxide content begins to rise, which is easy to cause "69" (oxygen content ≥ 6% and carbon monoxide ≥ 9%) dry dust removal automatic gun lifting accidents. It is not conducive to the improvement of the technical and economic indicators of the converter and the improvement of production efficiency. Summary of the invention

[0003] The purpose of the present invention is to provide a method for judging the ignition condition of the converter. By monitoring the oxygen content of the flue gas in the furnace flue, the ignition condition of the blowing can be quickly and accurately judged, thereby avoiding splashing accidents caused by non-ignition of the blowing and blowing stop accidents caused by automatic lifting of the dry dust removal gun, thereby achieving the purpose of improving the technical and economic indicators and production efficiency of the converter, and effectively solving the above-mentioned problems existing in the background technology.

[0004] The technical solution of the present invention is: a method for judging the ignition condition of a converter, comprising the following steps: (1) Monitor the oxygen content of flue gas in the flue at the furnace mouth; (2) Start monitoring timing from the time the converter sends a blow-on signal; (3) Determine whether the blowing is on but no fire has occurred by comparing the flue gas oxygen content value at the specified time, or if: ① the difference between the flue gas oxygen content at 20 seconds of blowing and the flue gas oxygen content at the time of blowing is ≤2.0%; ② the flue gas oxygen content decreases by ≤0.5% / second after 15 to 20 seconds of blowing, and it is judged that the blowing is on but no fire has occurred; (4) After determining that the blow-through has not ignited, ensure that the blow-through ignites normally by lowering the oxygen gun height, increasing the oxygen flow rate, and increasing the bottom blow flow rate.

[0005] In the step (1), the frequency of monitoring the oxygen content of flue gas in the furnace flue is 1 second / time.

[0006] In the step (2), the time when the converter sends out a blowing start signal is the blowing start time.

[0007] In the step (3), the difference between the oxygen content of the flue gas 20 seconds after the blowing is started and the oxygen content when the blowing is started is: the oxygen content of the flue gas when the blowing is started minus the oxygen content of the flue gas 20 seconds after the blowing is started; the decrease in oxygen content between 15 and 20 seconds after the blowing is started is: the current oxygen content of the flue gas minus the oxygen content of the flue gas in the next second.

[0008] The beneficial effects of the present invention are as follows: by monitoring the oxygen content of the flue gas in the furnace flue, the blowing and ignition conditions can be quickly and accurately determined, thereby avoiding splashing accidents caused by non-ignition during blowing and blowing stop accidents caused by automatic lifting of the dry dust removal gun, thereby achieving the purpose of improving the technical and economic indicators and production efficiency of the converter. DETAILED DESCRIPTION

[0009] In order to make the purpose, technical solutions and advantages of the invention implementation cases clearer, the technical solutions of the present invention will be clearly and completely described in conjunction with the implementation cases below. Obviously, the implementation cases described are only a small part of the implementation cases of the present invention, rather than all the implementation cases. Based on the implementation cases in the present invention, all other implementation cases obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0010] A method for judging the ignition status of a converter, comprising the following steps: (1) Monitor the oxygen content of flue gas in the flue at the furnace mouth; (2) Start monitoring timing from the time the converter sends a blow-on signal; (3) Determine whether the blowing is on but no fire has occurred by comparing the flue gas oxygen content value at the specified time, or if: ① the difference between the flue gas oxygen content at 20 seconds of blowing and the flue gas oxygen content at the time of blowing is ≤2.0%; ② the flue gas oxygen content decreases by ≤0.5% / second after 15 to 20 seconds of blowing, and it is judged that the blowing is on but no fire has occurred; (4) After determining that the blow-through has not ignited, ensure that the blow-through ignites normally by lowering the oxygen gun height, increasing the oxygen flow rate, and increasing the bottom blow flow rate.

[0011] In the step (1), the frequency of monitoring the oxygen content of flue gas in the furnace flue is 1 second / time.

[0012] In the step (2), the time when the converter sends out a blowing start signal is the blowing start time.

[0013] In the step (3), the difference between the oxygen content of the flue gas 20 seconds after the blowing is started and the oxygen content when the blowing is started is: the oxygen content of the flue gas when the blowing is started minus the oxygen content of the flue gas 20 seconds after the blowing is started; the decrease in oxygen content between 15 and 20 seconds after the blowing is started is: the current oxygen content of the flue gas minus the oxygen content of the flue gas in the next second. Example 1

[0014] Before starting blowing in the converter, ensure that the flue gas oxygen content monitoring equipment in the furnace flue is operating normally. After adding scrap steel and iron to the converter, start lowering the gun and start blowing. The monitoring timing starts from the time the converter sends a start-blowing signal. At the moment of blowing, the flue gas monitoring equipment detects that the flue gas oxygen content is 21.0% at the moment of blowing, and the flue gas oxygen content is 19.5% after 20 seconds of blowing. The difference between the flue gas oxygen content at the time of blowing and the flue gas oxygen content at 20 seconds is 1.5%≤2.0%, which means that the blowing has not ignited. The operator needs to ensure normal ignition by lowering the height of the oxygen gun, increasing the oxygen flow rate, and increasing the bottom blowing flow rate. Example 2

[0015] Before starting blowing in the converter, ensure that the flue gas oxygen content monitoring equipment in the furnace flue is operating normally. After adding scrap steel and iron to the converter, start lowering the gun and start blowing. The monitoring timing starts from the converter sending a blowing signal. At the moment of blowing, the flue gas monitoring equipment detects that the flue gas oxygen content is 21.0% at the moment of blowing, 20.5% at 15 seconds after blowing, 19.5% at 16 seconds after blowing, 18.5% at 17 seconds after blowing, 17.5% at 18 seconds after blowing, 18.5% at 19 seconds after blowing, and 18.9% at 20 seconds after blowing. The difference between the flue gas oxygen content value at the start of blowing and the flue gas oxygen content at 20 seconds is 2.1%>2.0%, but the flue gas oxygen content decreases from 18 seconds to 19 seconds after blowing by -1.0%≤0.5% / second, and the flue gas oxygen content decreases from 19 seconds to 20 seconds after blowing by -0.4%≤0.5% / second. It is judged that the blowing did not ignite. The operator needs to ensure normal ignition by lowering the oxygen gun height, increasing the oxygen flow rate, and increasing the bottom blowing flow rate. Example 3

[0016] Before starting blowing in the converter, ensure that the flue gas oxygen content monitoring equipment in the flue gas duct at the furnace mouth is operating normally. After adding scrap steel and iron to the converter, the gun is lowered and blowing begins. The monitoring timing starts from the converter sending a blowing signal. At the time of blowing, the flue gas monitoring equipment detects that the flue gas oxygen content is 21.0% at the time of blowing, 20.5% at 15 seconds after blowing, 19.5% at 16 seconds after blowing, 18.5% at 17 seconds after blowing, 17.5% at 18 seconds after blowing, 18.5% at 19 seconds after blowing, and 19.5% at 20 seconds after blowing. The difference between the flue gas oxygen content value and the flue gas oxygen content at -20 seconds is 1.5%≤2.0%, and the decrease in the flue gas oxygen content from 18 seconds to 19 seconds and from 19 seconds to 20 seconds after blowing is -1.0%≤0.5% / second. It is judged that the blow did not ignite. The operator needs to ensure normal ignition by lowering the oxygen gun height, increasing the oxygen flow rate, and increasing the bottom blow flow rate. Example 4

[0017] Before the converter starts blowing, ensure that the flue gas oxygen content monitoring equipment in the furnace flue is operating normally. After adding scrap steel and iron to the converter, the gun is lowered and the blowing is started. The monitoring timing starts from the converter sending the blowing signal. At the time of blowing, the flue gas monitoring equipment detects that the flue gas oxygen content is 21.0% at the time of blowing, 20.5% at 15 seconds after blowing, 19.5% at 16 seconds after blowing, 18.5% at 17 seconds after blowing, 17.5% at 18 seconds after blowing, 15.5% at 19 seconds after blowing, and 13.5% at 20 seconds after blowing. The difference between the flue gas oxygen content value at the time of blowing and the flue gas oxygen content at 20 seconds is 7.5%>2.0%, and the decrease in the flue gas oxygen content per second is>0.5% / second from 15 to 20 seconds after blowing. It is judged that the blowing is on fire. The operator can follow the normal operation later.

[0018] Usage statistics: Before adopting this method, the monitoring and treatment time of the three converters of the Long Products Division of Tangshan Branch of Hebei Iron and Steel Co., Ltd. was 90-120 seconds, the splash rate caused by the failure to ignite was 7.2%, and the stop accidents caused by the automatic lifting of the dry dust removal gun due to the failure to ignite were 5 times / month. After adopting this method, the monitoring and treatment time of the failure to ignite was within 20 seconds, the splash rate caused by the failure to ignite was reduced to 0.2%, and the stop accidents caused by the automatic lifting of the dry dust removal gun due to the failure to ignite were reduced to 0 times / month.

[0019] The present invention can quickly and accurately judge the ignition status of the blow-on within 20 seconds of the blow-on by using the flue gas oxygen content value in the furnace flue, which is 90 to 120 seconds earlier than the judgment by artificial flame and the judgment by the flue gas value at the outlet of the dry dust removal electrostatic precipitator. It can effectively shorten the accident prediction and processing time by 70 to 100 seconds, effectively avoid the splashing accident caused by the failure of the blow-on and the stop accident caused by the automatic lifting of the dry dust removal gun, and achieve the purpose of improving the technical and economic indicators and production efficiency of the converter.

Claims

1. A method for judging the ignition status of a converter, characterized in that The following steps are involved: (1) Monitor the oxygen content of flue gas in the flue at the furnace mouth; (2) Start monitoring timing from the time the converter sends a blow-on signal; (3) Determine whether the blowing is started without ignition by comparing the flue gas oxygen content value at the specified time, or if: ① The difference between the flue gas oxygen content 20 seconds after the blowing is started and the flue gas oxygen content when the blowing is started is ≤ 2.0%; ② If the oxygen content of flue gas decreases by ≤0.5% / second after the blowing is started for 15 to 20 seconds, it is judged that the blowing is started but no fire occurs; (4) After determining that the blow-through has not ignited, ensure that the blow-through ignites normally by lowering the oxygen gun height, increasing the oxygen flow rate, and increasing the bottom blow flow rate.

2. A method for judging the ignition condition of a converter according to claim 1, characterized in that: In the step (1), the frequency of monitoring the oxygen content of flue gas in the furnace flue is 1 second / time.

3. A method for judging the ignition condition of a converter according to claim 1, characterized in that: In the step (2), the time when the converter sends out a blowing start signal is the blowing start time.

4. A method for judging the ignition condition of a converter according to claim 1, characterized in that: In the step (3), the difference between the oxygen content of the flue gas 20 seconds after the blowing is started and the oxygen content when the blowing is started is: the oxygen content of the flue gas when the blowing is started minus the oxygen content of the flue gas 20 seconds after the blowing is started; the decrease in oxygen content between 15 and 20 seconds after the blowing is started is: the current oxygen content of the flue gas minus the oxygen content of the flue gas in the next second.