JP2003055710A - Method for detecting abnormal blow of immersed lance - Google Patents

Abstract

PROBLEM TO BE SOLVED: To correctly detect any abnormal blow of an immersed lance caused by the breakage thereof without any constant monitoring or requiring any working skill. SOLUTION: In a method for detecting whether or not the blow is normally performed when the powder 1A fed from at least one pressure vessel 2A via a carrier gas is blown into a molten metal 51 in a torpedo 50 from a tip of the immersed lance 43, the vibration caused by blowing the powder 1A and the gas in the molten metal 51 from the tip of the immersed lance 43 is detected by an accelerometer 70 provided on a torpedo car 50a, and the abnormal blow of the immersed lance 43 is detected when the detected vibration is below the threshold of the vibration in the abnormal blow of the immersed lance 43 according to the powder blowing speed which is obtained in advance.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method in which powder blown from at least one pressure vessel via a carrier gas is blown into a molten metal in a torpedo from the tip of an immersion lance. The present invention relates to a method for detecting whether or not the operation is normally performed.

[0002]

2. Description of the Related Art Conventionally, for example, powder (refining agent) contained in a plurality of or one pressure vessel is connected to each pressure vessel.
In the operation of cutting out into a blowing line of a book, pneumatically feeding it with a carrier gas, and blowing it into the molten metal in the torpedo through an immersion lance to remove impurities in the molten metal, dipping in a molten metal Lance is a consumable item, and it is cost effective to use multiple charges. Therefore, it is used until the powder injection from the tip of the immersion lance is interrupted during the powder injection process, in other words, during the immersion lance, especially until the slag surface is melted or broken and cannot be used. In order to determine whether the immersion lance is melted or broken, the operator needs to constantly monitor the blowing condition.

Further, even an inexperienced operator may not notice the melting damage or breakage of the immersion lance even while monitoring the blowing condition. If the operation is performed without being noticed abnormally, the impurity components in the molten metal will not fall to the target component values, the processing time will be extended, the unit price of the current process and the next process will increase, and the environment will deteriorate. This may lead to a reduction in dust collection function.

Therefore, improvements have been made to confirm the condition of the immersion lance that returns to the standby position after each operation, and empirically replace it in advance, or to extend the life of the immersion lance itself.

[0005]

However, even if the immersion lance is replaced in advance, an abnormality of the immersion lance often occurs during the powder blowing process after the replacement, and therefore, the operator always keeps the cut-off. The actual situation is that the operation is monitored by monitoring the blowing condition, and if the immersion lance is abnormal, it is left to the operator to make judgments based on the empirical rules.

The present invention has been made in view of the above circumstances and does not require constant supervision during powder injection, and does not depend on the skill level of operation, and the melting damage of the immersion lance In addition, it is possible to provide a method for detecting a blow-in abnormality of a dip lance which can accurately detect a blow-in abnormality of the dip lance due to breakage or the like, which can improve the usage rate of the dip lance and reduce the operating cost. To aim.

[0007]

In order to achieve the above-mentioned object, the invention according to claim 1 is a method in which a powder fed from at least one pressure vessel via a carrier gas is fed into a torpedo from the tip of an immersion lance. While blowing into the molten metal of
In the method for detecting whether or not the blowing is normally performed, vibration when reacting due to the powder and / or the carrier gas being blown into the molten metal from the tip of the immersion lance is used. When the detected vibration value falls below a threshold value of the vibration value at the time of abnormal blowing of the immersion lance according to the powder blowing speed that has been previously obtained, the blowing abnormality of the immersion chest is detected. It is characterized by

According to a second aspect of the present invention, in the first aspect, the detected vibration value is calculated based on a signal from an accelerometer installed on the torpedo.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION An example of an embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic diagram of a powder blowing apparatus to which a method for detecting abnormalities in blowing of an immersion lance which is an example of an embodiment of the present invention is applied, and FIG. 2 is a threshold value when abnormal blowing of an immersion lance and total powder blowing are performed. FIG. 3 is a graph showing the relationship with the injection speed, FIG. 3 is a flow chart for explaining the detection of the injection abnormality of the immersion lance during operation, the immersion lance position, the carrier gas flow rate, the powder injection speed and the time chart of the vibration value. It is a figure.

As shown in FIG. 1, this powder blowing device has powders 1A to 1D (1A: iron oxide, 1B:
Dispensers (pressure vessels) 2A to 2D for accommodating lime, 1C: spare, 1D: soda ash) and pressurizing them to a predetermined pressure are provided. Powders 1A to 1D in the dispensers 2A to 2D
Is pneumatically sent together with the carrier gas 31 to a consumable immersion lance 43 via a powder transfer line 40, and is blown into the hot metal 51 (molten metal) in the torpedo 50 from the tip of the immersion lance 43. .

In FIG. 1, reference numeral 3 is a dispenser pressure gauge for measuring dispenser pressure, 4 is a dispenser pressure adjusting valve for controlling the dispenser to a predetermined pressure, a predetermined differential pressure or atmospheric pressure, 5 is a pre-pressurization line, and 6 Is a pre-pressurization valve, 7 is a pressurized gas, 8 is a pressurization control line, 9 is a pressurization valve, 10 is an exhaust control line, 11 is an individual transfer line, 12 is a quick exhaust valve, 13 is an intermediate exhaust valve, and 14 is A load cell for measuring the weight of powder in the dispenser, 16 an aeration line for fluidizing the powder cut out from the dispenser through an aeration gas 15, 17 an aeration valve, 18
Is an outlet valve that cuts out the powder from the dispenser, and 19 is a variable valve that controls the amount of powder cut out from the dispenser.
In the dispensers 2B to 2D, the reference numerals 3 to 17 are omitted.

Reference numeral 32 is a carrier gas flow meter, 3
3 is a carrier gas valve, 34 is a carrier gas flow rate adjusting valve,
35 is a carrier gas line, 36 is a blow line pressure gauge, 37 is a blow gas flow meter, 38 is a blow gas valve, 3
9 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 moving the immersion lance 43 up and down, and 45 is capable of traveling, tilting, and switching to the auxiliary lance. Lancer, 52 is slag, 60 is a control device for controlling powder injection from the tip of the immersion lance 43, 6
Reference numeral 1 is an operation disk.

Here, in this embodiment, the accelerometer 70 is simply installed on the torpedo 50 and the accelerometer 7 is installed.
After the signal of 0 is filtered by the signal converter 71 and converted into a vibration value, this is output as the detected vibration value to the control device 60, and the control device 60 compares this detected vibration value with a preset threshold value and dips it. It is configured to detect whether or not the powder is normally blown from the tip of the lance 43 into the hot metal 51 in the torpedo 50.

The accelerometer 70 is installed on the torpedo car 50a when the torpedo 50 is dispatched to the hot metal pretreatment plant. Then, the powder blowing process is started, the immersion lance 43 descends, and when the powder starts to be blown into the hot metal 51 from the tip of the immersion lance 43, the accelerometer 70
Detects the vibration generated in the torpedo 50 due to the reaction and stirring of the powder and the hot metal 51 in the bath. On the other hand, when the immersion lance 43 is melted or broken in the middle and the powder is not blown into the hot metal 51, the reaction between the powder and the hot metal 51 in the bath and the stirring are lost, and the vibration of the torpedo 50 is not detected. . Therefore, by setting a reference for the vibration value generated by the torpedo 50, it is possible to detect the blow-in abnormality of the immersion lance 43 when the detected vibration value falls below this reference value.

In this case, since the degree of immersion of the immersion lance 43 differs for each charge, it is not known which part of the immersion lance 43 is melted or broken. Further, the brand of the powder to be blown in and the powder blowing speed greatly change depending on the amount of impurities in the hot metal 51, the temperature, and the presence or absence of forming. Therefore, the generated vibration value also changes depending on them.

Therefore, the threshold of the vibration value which is a reference is
It is considered that each powder is caused by the degree of the powder blowing speed, and it is determined from the following equation 1 and FIG. 2 as a relation between the total powder blowing speed and the blowing abnormality due to the melting damage or breakage of the immersion lance. , These can be empirically obtained through normal operation in a normal immersion lance. WtPV = WaPV x Ka + WbPV x Kb + WcPV x Kc + WdPV x Kd (1) WtPV: Total blowing speed (kg / min) WaPV: Blowing speed of powder 1A (kg / min) Ka: Powder 1A coefficient WbPV: Powder Blowing speed of 1B (kg / min) Kb: Coefficient of powder 1B WcPV: Blowing speed of powder 1C (kg / min) Kc: Coefficient of powder 1C WdPV: Blowing speed of powder 1D (kg / min) Kd: powder 1D coefficient, and the detection signal from the accelerometer 70 is converted into a signal converter 71.
When it is output to the control device 60 as a detected vibration value after being filtered by and converted into a vibration value by the control device 70, the control device 70 compares the detected vibration value with the threshold value, and when the detected vibration value is below the threshold value, the immersion lance 43 is detected. It is determined that the injection of the powder into the hot metal 51 in the torpedo 50 from the tip of the is abnormal, and an alarm or the like is output.

FIG. 3 shows a control device 70 during powder injection.
5 is a flow chart for detecting the blow-in abnormality of the immersion lance including the operation of. First, when the blowing start PB is turned on at the operation desk 71 in step S1, the immersion lance 43 descends to the blow position (step S2), and when it is detected that the immersion lance 43 reaches the blow position in step S3, The process proceeds to S4 and the blow is started.

Next, when the blow time is up in step S5, the process proceeds to step S6, the immersion lance 43 is lowered to the blowing position, and when it is detected that the immersion lance 43 reaches the blowing position in step S7, the step is performed. The process moves to S8, the blowing of the powder into the hot metal 51 from the tip of the immersion lance 43 is started, the blowing is stopped, and the process proceeds to step S9.

At step S9, when the outlet valve 18 is opened for a predetermined time after the opening, the process proceeds to step S10. At step S10, the total blowing speed of the powder is determined by using FIG. 2 and the above equation (1). Corresponding immersion lance 43
The threshold value of the vibration value at the time of abnormal blowing is calculated. Next, the process proceeds to step S11, 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, and if the detected vibration value is below the threshold value, the step is performed. The process shifts to S12 to output the blow-in abnormality warning of the immersion lance 43, and if not lower, the process shifts to step S14.

When the alarm is output in step S12, the blow stop PB is turned on at the operation desk 61 (step S1).
3) and shifts to step S17. In step S17, the blowing of the powder from the immersion lance 43 is stopped and the blowing is started. When the end timer is timed out in step S18, the process proceeds to step S19 and the immersion lance 43 is moved to the blow position.

Then, in step S20, the immersion lance 43 is used.
Has been detected to have reached the blow position, and when the blow timer has timed out in step S21, the process proceeds to step S22, where the immersion lance 43 rises to the upper limit position, and in step S23 the immersion lance 43 reaches the upper limit position. When the arrival is detected, the process ends. On the other hand, step S
If the detected vibration value does not fall below the threshold value in step 11, step S
14, the amount of powder blown reaches the predetermined amount in step S14, or it is determined in step S15 that the blowing has ended and the blow stop PB is turned on in step S16, and the process proceeds to step S17. The processes of steps S17 to S23 are performed.

As described above, in this embodiment, the immersion lance 43 due to melting damage, breakage, etc. of the immersion lance 43 does not require constant monitoring during powder injection and does not require work skill. Since it is possible to accurately detect the blow-in abnormality, it is possible to improve the usage rate of the immersion lance 43 and reduce the operating cost. In the above embodiment, the case where the accelerometer 70 is installed in the torpedo car 50a is taken as an example, but 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. The vibration value at the time of abnormal blowing may be detected, and the accelerometer 70 may be of a contact type or a non-contact type.

Furthermore, the present invention can be applied to the case where only the carrier gas is blown, without being limited to during the powder blowing.

[0024]

EXAMPLE FIG. 4 is a time chart diagram of the immersion lance position, carrier gas flow rate, powder injection speed and vibration value when the immersion lance injection abnormality is detected by the method of the present invention in the injection apparatus having the above construction. Show. Powder 1 for dephosphorization treatment
Immediately after starting the injection from the immersion lance 43 with A and 1B (T1 in the figure), the injection speed of the powder 1A was 116.
kg / min, blowing speed of powder 1B is 149 kg / m
in, total blow rate from these is 205kg / m
In, the darkness value of the immersion lance 43 when the blowing was abnormal was 18%. On the other hand, the vibration value detected by the accelerometer 70 is 8.7%, which is not a blow-in abnormality of the immersion lance 43. When the blowing time has passed a predetermined time (T in the figure
2), the vibration value detected by the accelerometer 70 has decreased.
The data before and after this are shown in Table 1.

[0025]

[Table 1]

As can be seen from Table 1, 250 seconds after the start of the blowing, the detected vibration value finally fell below the threshold value when the immersion lance was abnormally blown, and the immersion lance blowing abnormal alarm was issued. At this time,
Blowing speed of powder 1A is 257 kg / min, powder 1B
The blowing rate was 91 kg / min, the total blowing rate was 311 kg / min, and the threshold value for abnormal immersion lance blowing was 12.1%. After that, when blowing was stopped and the immersion lance was raised and checked, the immersion lance was bent in the middle, and an abnormality in the immersion lance could be confirmed.

[0027]

As is apparent from the above description, according to the present invention, when the powder is blown into the molten metal through the immersion lance, it is not always supervised and Since it is possible to accurately detect the blowing abnormality of the immersion lance due to breakage etc. without requiring work skill, it is possible to improve the usage rate of the immersion lance and reduce the operating cost. .

[Brief description of drawings]

FIG. 1 is a schematic diagram of a powder injection device to which a method for detecting an injection abnormality of an immersion lance, which is an example of an embodiment of the present invention, is applied.

FIG. 2 is a graph showing a relationship between a threshold value and a powder total blowing speed at the time of abnormal blowing of the immersion lance.

FIG. 3 is a flow chart for explaining the detection of a blow-in abnormality of the immersion lance during operation.

FIG. 4 is a time chart of the immersion lance position, carrier gas flow rate, powder blowing speed, and vibration value.

[Explanation of symbols]

1A to 1D ... powder 2A to 2D ... Dispenser (pressure vessel) 43 ... Immersion lance 50 ... Torpedo 51 ... Hot metal (molten metal) 60 ... Control device 70 ... Accelerometer 71 ... Signal converter

   ─────────────────────────────────────────────────── ─── Continued front page    F-term (reference) 4K013 BA03 BA05 CA15 CB04 EA02                       EA03 EA13 FA00 FA11 FA12                 4K014 AA02 AA03 AB03 AB04 AB13                       AC14 AD01 AD17 AD27                 4K056 AA06 CA02 FA11

Claims (2)

[Claims] 1. 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. In the method for detecting whether or not the powder and / or the carrier gas reacts by being blown into the molten metal from the tip of the immersion lance, the detected vibration value is detected in advance. Blowing of the immersion lance, which is characterized by detecting the blowing abnormality of the immersion lance when the vibration value at the time of abnormal blowing of the immersion lance corresponding to the determined powder blowing speed falls below a threshold value. Abnormality detection method. 2. The method for detecting a blow-in abnormality of an immersion lance according to claim 1, wherein the detected vibration value is calculated based on a signal from an accelerometer installed in the torpedo.