JP3994701B2 - Detection method of immersion lance blowing abnormality - Google Patents

Description

【００２６】
表１から判るように、吹込み開始２５０秒後に遂に検出振動値が浸漬ランス吹込み異常時の閾値を下回り、浸漬ランス吹込み異常警報が出た。このとき、粉体１Ａの吹込み速度は２５７ｋｇ／ｍｉｎ、粉体１Ｂの吹込み速度は９１ｋｇ／ｍｉｎ、トータル吹込み速度は３１１ｋｇ／ｍｉｎ、浸漬ランス吹込み異常時の閾値は１２．１％であった。その後、吹込み停止を掛けて浸漬ランスを上昇させて確認したところ、浸漬ランスが途中から折れ曲がっており、浸漬ランスの異常が確認できた。
【００２７】
【発明の効果】
上記の説明から明らかなように、本発明によれば、浸漬ランスを介して溶融金属中に粉体吹込みを行っている際に、常時付きっきりで監視することなく、また、作業熟練度も必要とすることなく、折損等による浸漬ランスの吹込み異常を正確に検出することができるので、浸漬ランスの使用率向上と操業コストの低減を図ることができるという効果が得られる。
【図面の簡単な説明】
【図１】本発明の実施の形態の一例である浸漬ランスの吹込み異常検出方法を適用する粉体吹込み装置の概略図である。
【図２】浸漬ランスの吹込み異常時の閾値と粉体トータル吹込み速度との関係を示すグラフ図である。
【図３】操業中における浸漬ランスの吹込み異常検出を説明するためのフローチャート図である。
【図４】浸漬ランス位置、搬送ガス流量、粉体吹込み速度及び振動値のタイムチャート図である。
【符号の説明】
１Ａ〜１Ｄ…粉体
２Ａ〜２Ｄ…ディスペンサ（圧力容器）
４３…浸漬ランス
５０…トーピード
５１…溶銑（溶融金属）
６０…制御装置
７０…加速度計
７１…信号変換器[0001]
BACKGROUND OF THE INVENTION
In the present invention, when the powder fed from at least one pressure vessel via the carrier gas is blown into the molten metal in the torpedo from the tip of the immersion lance, the blowing is normally performed. The present invention relates to a method of detecting whether or not.
[0002]
[Prior art]
Conventionally, for example, powders (refining agents) stored in a plurality of pressure vessels or one pressure vessel are cut out into one blowing line connected to each pressure vessel, aired with carrier gas, and torpedo via an immersion lance In the operation of blowing in the molten metal to remove impurities in the molten metal, the immersion lance immersed in the molten metal is a consumable item, and it is advantageous in terms of cost to use many charges. Therefore, it is used until the powder blowing from the tip of the immersion lance is stopped during the powder blowing process, in other words, in the middle of the immersion lance, especially the vicinity of the slag surface is melted or broken. Whether the immersion lance is melted or broken must always be monitored by the operator.
[0003]
Inexperienced operators may not be aware of the melting or breakage of the immersion lance even when monitoring the blowing conditions. If the operation is carried out without being noticed abnormally, the impurity components in the molten metal will not decrease to the target component value, the processing time will be extended, the raw unit price in the current process and the next process will be increased, and the environment will deteriorate. It may cause a decrease in dust collection function.
[0004]
Therefore, improvements have been made to confirm the status of the immersion lance that returns to the standby position after each operation and replace it empirically in advance or to extend the life of the immersion lance itself.
[0005]
[Problems to be solved by the invention]
However, even if the immersion lance is replaced in advance, it is often the case that an abnormality of the immersion lance occurs during the powder blowing process after the replacement. The actual situation is that the lance abnormalities are entrusted to the judgment based on the empirical rules of individual operators.
[0006]
The present invention has been made paying attention to the above circumstances, does not require constant monitoring during powder blowing, and does not depend on the skill level of the work, and the immersion lance is melted, broken, etc. An object of the present invention is to provide an immersion lance blowing abnormality detection method capable of accurately detecting an immersion lance blowing abnormality caused by the above, and thereby improving the usage rate of the immersion lance and reducing the operation cost. .
[0007]
[Means for Solving the Problems]
In order to achieve the above object, according to the first aspect of the present invention, the powder blown from the at least one pressure vessel through the carrier gas is blown into the molten metal in the torpedo from the tip of the immersion lance. In the method for detecting whether or not the blowing is normally performed,
When the powder is blown into the molten metal from the tip of the immersion lance, vibration when reacting with the molten metal is detected, and the detected vibration value corresponds to the powder blowing speed determined in advance. When the vibration value of the immersion lance is abnormally lower than the vibration threshold, the abnormality of the immersion lance is detected .
The detected vibration value is calculated based on a signal from an accelerometer installed in the torpedo .
[0009]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an example of an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a schematic view of a powder blowing apparatus to which an immersion lance blowing abnormality detection method according to an embodiment of the present invention is applied. FIG. FIG. 3 is a graph showing the relationship with the injection speed, FIG. 3 is a flow chart for explaining the detection of the immersion lance in operation, the time chart of the immersion lance position, the carrier gas flow rate, the powder injection speed, and the vibration value FIG.
[0010]
As shown in FIG. 1, this powder blowing apparatus accommodates each powder 1A-1D (1A: iron oxide, 1B: lime, 1C: reserve, 1D: soda ash) and pressurizes it to a predetermined pressure. Dispensers (pressure containers) 2A to 2D are provided. The powders 1A to 1D in the dispensers 2A to 2D are fed together with the carrier gas 31 to the consumable immersion lance 43 via the powder carrier line 40, and the hot metal 51 (melted) in the torpedo 50 from the tip of the immersion lance 43. Metal).
[0011]
In FIG. 1, reference numeral 3 is a dispenser pressure gauge for measuring the dispenser pressure, 4 is a dispenser pressure regulating valve for controlling the dispenser to a predetermined pressure, a predetermined differential pressure or an atmospheric pressure, 5 is a pre-pressurization line, and 6 is a pre-pressurization line. Pressure valve, 7 is a pressurized gas, 8 is a pressure control line, 9 is a pressure valve, 10 is an exhaust control line, 11 is an individual transfer line, 12 is an emergency exhaust valve, 13 is an intermediate exhaust valve, 14 is in the dispenser A load cell for measuring the weight of the powder, 16 is an aeration line for fluidizing powder cut out from the dispenser via the aeration gas 15, 17 is an aeration valve, 18 is an outlet valve for cutting out powder from the dispenser, and 19 is powder cut out from the dispenser. This is a variable valve for controlling the body weight, and the reference numerals 3 to 17 are not shown in the dispensers 2B to 2D.
[0012]
Reference numeral 32 denotes a carrier gas flow meter, 33 denotes a carrier gas valve, 34 denotes a carrier gas flow rate adjustment valve, 35 denotes a carrier gas line, 36 denotes a blowing line pressure gauge, 37 denotes a blow gas flow meter, 38 denotes a blow gas valve, 39 Is a blow gas line, 41 is a lance back pressure gauge, 42 is an injection lance holder for connecting the immersion lance 43, 44 is a motor for raising and lowering the immersion lance 43, 45 is a lance car capable of running, tilting and switching to a spare lance. , 52 is a slag, 60 is a control device for controlling the blowing of powder from the tip of the immersion lance 43, and 61 is an operation disk.
[0013]
Here, in this embodiment, the accelerometer 70 is simply installed on the torpedo 50, and the signal of the accelerometer 70 is filtered by the signal converter 71 and converted into a vibration value, which is used as a detected vibration value. Output to the control device 60, and the control device 60 compares the detected vibration value with a preset threshold value, and the powder is normally blown from the tip of the immersion lance 43 into the hot metal 51 in the torpedo 50. It is designed to detect whether or not.
[0014]
The accelerometer 70 is installed on the torpedo car 50a when the torpedo 50 is dispatched to the hot metal pretreatment factory.
When the powder blowing process is started and the dipping lance 43 is lowered and the powder starts to be blown into the hot metal 51 from the tip of the dipping lance 43, the accelerometer 70 causes the bath of the powder and hot metal 51 to move. The vibration generated in the torpedo 50 due to the middle reaction or stirring is detected. -On the other hand, when the middle of the immersion lance 43 is melted or broken and the powder is no longer blown into the hot metal 51, the reaction and stirring of the powder and the hot metal 51 are eliminated, and the vibration of the torpedo 50 is not detected. . Accordingly, by providing a reference for the vibration value at which the torpedo 50 is generated, it is possible to detect an abnormal blowing of the immersion lance 43 when the detected vibration value falls below this reference value.
[0015]
In this case, since the immersion degree of the immersion lance 43 differs for each charge, it is not known which part of the immersion lance 43 is melted or broken. The brand of powder to be blown in and the powder blowing speed vary greatly depending on the amount and temperature of impurities in the hot metal 51 and the presence or absence of forming. Therefore, the generated vibration value varies depending on them.
[0016]
Therefore, it is considered that the threshold value of the vibration value serving as a reference is caused by the degree of the powder blowing speed for each powder and from the following formula 1 and FIG. It is determined as a relationship with blowing abnormality due to breakage, and these may be obtained empirically in a normal immersion lance through operation.
WtPV = WaPV × Ka + WbPV × Kb + WcPV × Kc + WdPV × Kd (1)
WtPV: Total blowing speed (kg / min)
WaPV: Powder 1A blowing speed (kg / min) Ka: Powder 1A coefficient WbPV: Powder 1B blowing speed (kg / min) Kb: Powder 1B coefficient WcPV: Powder 1C blowing speed ( kg / min) Kc: Powder 1C coefficient WdPV: Powder 1D blowing speed (kg / min) Kd: Powder 1D coefficient The detection signal from the accelerometer 70 is filtered by the signal converter 71 into a vibration value. and outputs to the controller 60 as a detection vibration value it after conversion, the control device 60, from the tip of the immersion lance 43 to come and detection vibration values as compared to the detecting vibration value and the threshold value is below the threshold value of the torpedo 50 It is determined that the powder injection into the hot metal 51 is abnormal, and an alarm or the like is output.
[0017]
FIG. 3 shows a flowchart for detecting abnormalities in blowing the immersion lance, including the operation of the control device 60 during powder blowing.
First, when the blowing start PB is turned on at the operation desk 61 in step S1, the immersion lance 43 is lowered to the blow position (step S2), and when it is detected in step S3 that the immersion lance 43 has reached the blow position, step The process proceeds to S4 and blow is started.
[0018]
Next, when the blow time is up in step S5, the process proceeds to step S6 and the immersion lance 43 is lowered to the blowing position, and when it is detected in step S7 that the immersion lance 43 has reached the blowing position, the process proceeds to step S8. Then, the blowing of the powder from the tip of the immersion lance 43 into the hot metal 51 is started and the blow is stopped, and the process proceeds to step S9.
[0019]
In step S9, when the predetermined time has elapsed after the outlet valve 18 is opened, the process proceeds to step S10. In step S10, the immersion according to the total blowing speed of the powder using FIG. 2 and the above equation (1). The threshold value of the vibration value when the lance 43 is abnormally blown is calculated.
Next, the process proceeds to step S11, where the detected vibration value obtained by converting the detection signal from the accelerometer 70 by the signal converter 71 is compared with the threshold value. If the detected vibration value falls below the threshold value, the step is performed. The process proceeds to S12 to output a blow abnormality alarm for the immersion lance 43. If not lower, the process proceeds to step S14.
[0020]
When an alarm is output in step S12, the blow stop PB is turned on at the operation desk 61 (step S13), and the process proceeds to step S17.
In step S17, the blowing of powder from the immersion lance 43 is stopped and blowing is started. When the end timer expires in step S18, the process proceeds to step S19, and the immersion lance 43 is raised to the blow position.
[0021]
Next, when it is detected in step S20 that the immersion lance 43 has reached the blow position, and when the blow timer expires in step S21, the process proceeds to step S22, where the immersion lance 43 rises to the upper limit position, and step S23. When it is detected that the immersion lance 43 has reached the upper limit position, the process ends.
On the other hand, if the detected vibration value does not fall below the threshold value in step S11, the process proceeds to step S14. In step S14, it is determined that the blowing amount of the powder reaches a predetermined amount, or the blowing end is determined in step S15. When the blow stop PB is turned on, the process proceeds to step S17, and the processes of steps S17 to S23 are performed.
[0022]
As described above, in this embodiment, it is not necessary to constantly monitor the powder during blowing, and the blowing of the immersion lance 43 due to melting, breakage, or the like of the immersion lance 43 without requiring skill of operation. Since the abnormality can be detected accurately, the utilization rate of the immersion lance 43 can be improved and the operation cost can be reduced.
In the above embodiment, the case where the accelerometer 70 is installed in the torpedo car 50a is taken as an example. However, the present invention is not limited to this. For example, the accelerometer 70 is installed at the upper end position of the injection lance holder 42 or the immersion lance 43. Then, the vibration value at the time of abnormal blowing may be detected, and the accelerometer 70 may be either of a contact type or a non-contact type.
[0024]
【Example】
FIG. 4 shows a time chart of the immersion lance position, the carrier gas flow rate, the powder blowing speed, and the vibration value when an abnormality in the immersion lance is detected by the method of the present invention in the blowing apparatus having the above configuration.
Immediately after the start of blowing from the immersion lance 43 with the powders 1A and 1B to perform the dephosphorization process (T1 in the figure), the blowing speed of the powder 1A is 116 kg / min, and the blowing speed of the powder 1B is 149 kg / min, based on these, the total blowing speed was 205 kg / min, and the threshold when the blowing of the immersion lance 43 was abnormal was 8.7 %. On the other hand, the vibration value detected by the accelerometer 70 is 18 %, which is not an abnormality in blowing the immersion lance 43. When the blowing time has elapsed (T2 in the figure), the vibration value detected by the accelerometer 70 has decreased. The data before and after this is shown in Table 1.
[0025]
[Table 1]

[0026]
As can be seen from Table 1, the detected vibration value finally fell below the threshold value when the immersion lance was blown abnormally 250 seconds after the start of blowing, and an immersion lance blow abnormality alarm was issued. At this time, the blowing speed of the powder 1A is 257 kg / min, the blowing speed of the powder 1B is 91 kg / min, the total blowing speed is 311 kg / min, and the threshold when the immersion lance blowing is abnormal is 12.1%. there were. Thereafter, when the immersion lance was lifted and confirmed by stopping blowing, the immersion lance was bent from the middle, and it was confirmed that the immersion lance was abnormal.
[0027]
【The invention's effect】
As is apparent from the above description, according to the present invention, when powder is blown into the molten metal through the immersion lance, it is not necessary to monitor constantly and work skill is also required. Therefore, it is possible to accurately detect the abnormality in blowing the immersion lance due to breakage or the like, so that it is possible to improve the usage rate of the immersion lance and reduce the operation cost.
[Brief description of the drawings]
FIG. 1 is a schematic view of a powder blowing apparatus to which an immersion lance blowing abnormality detection method according to an embodiment of the present invention is applied.
FIG. 2 is a graph showing a relationship between a threshold value when an immersion lance is blown abnormally and a total powder blowing speed.
FIG. 3 is a flowchart for explaining detection of an abnormality in the immersion lance in operation.
FIG. 4 is a time chart of immersion lance position, carrier gas flow rate, powder blowing speed, and vibration value.
[Explanation of symbols]
1A-1D ... Powder 2A-2D ... Dispenser (pressure vessel)
43 ... immersion lance 50 ... torpedo 51 ... hot metal (molten metal)
60 ... Control device 70 ... Accelerometer 71 ... Signal converter

Claims (1)

Detects whether or not blowing is normally performed when blowing powder fed from at least one pressure vessel via carrier gas into the molten metal in the torpedo from the tip of the immersion lance In the way to
When the powder is blown into the molten metal from the tip of the immersion lance, vibration when reacting with the molten metal is detected, and the detected vibration value corresponds to the powder blowing speed determined in advance. When the vibration value of the immersion lance is abnormally lower than the vibration threshold, the abnormality of the immersion lance is detected .
An immersion lance blowing abnormality detection method, wherein the detected vibration value is calculated based on a signal from an accelerometer installed in the torpedo .

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