JP6962465B2 - Converter blowing method - Google Patents

Description

The present disclosure relates to a converter blowing method using a top blowing lance.

In the converter, blowing is performed using a top blowing lance (hereinafter, appropriately referred to as "lance"). In this blowing, oxygen gas is injected from the nozzle hole provided in the lance toward the hot metal surface (hot water surface) to stir the hot metal and remove Si, Mn, P and C by an oxidation reaction. During blowing, dust is generated from the converter due to the bounce and decarburization reaction of oxygen gas injected from the nozzle hole of the lance on the hot metal surface. The generated dust is discharged together with the exhaust gas. This dust is mainly composed of iron (iron, iron oxide), and it is desirable to reduce it because it leads to iron loss when discharged.

When blowing with a top-blown lance, the shape of the hot metal surface in the converter changes depending on the acid feeding rate and the lance height (nozzle tip position) when oxygen gas collides with the hot metal surface.
At a constant acid feeding rate, the smaller the lance gap, which is the distance between the hot metal surface and the tip of the nozzle, the more the shape of the hot metal when oxygen gas collides with the hot metal surface becomes a waterfall (inverted Ω cross section). It is known that the amount of dust generated can be reduced because the dust is not scattered and is easily taken into the hot metal. This is called hard blow.
On the other hand, it is known that if the lance gap is made too small, the nozzle is strongly affected by heat from the hot metal surface, so that the nozzle wears severely and the life of the lance is shortened. By shortening the life of the lance in this way, the frequency of replacement of the lance increases, which adversely affects the operation.

From the above, the lance gap has an optimum interval for reducing the amount of dust generated while maintaining the life of the lance, and it is desired to perform blowing at that interval. The optimum interval between the lance gaps (hereinafter, appropriately referred to as "optimum lance gap") is set according to the size of the converter and the acid feeding rate.
In order to set the lance gap to the optimum interval, it is necessary to grasp the height of the hot metal surface, and as a method thereof, for example, there is a technique disclosed in Japanese Patent Application Laid-Open No. 11-52049. Specifically, a mobile microwave transmission / reception antenna installed in the sublance hole of the upper hood of the converter after charging hot metal and scrap or can alloy (alloy iron in a drum can, etc.) into the converter. This is a method in which microwaves are transmitted into the furnace and the height of the hot metal surface (hot water level) is measured from the received signal.

The height of the hot metal surface is measured after the hot metal or the like is charged into the converter and before the start of blowing (before the start of blowing). Japanese Patent Application Laid-Open No. 11-52049 does not clearly describe the time required to measure the height of the hot metal surface, but since the hot metal surface immediately after charging is oscillating, it is oscillating for accurate grasping of the height. It is difficult to measure the height of the hot metal every time the hot metal or the like is charged into the converter because it is necessary to wait until the height becomes small and the productivity is affected.

Therefore, based on the measured value of the hot metal surface height when actually measured by the microwave hot metal surface meter, the estimated value (estimated hot metal surface height) of the hot metal surface height for each blowing when not actually measured is calculated by the following formula (estimated hot metal surface height). It is calculated using 1).
(Estimated hot metal surface _{level) = {(WTn-WT 0} ) / (ρπr 0 2)} + l 0 ··· (1)
Here, ρ is the iron specific gravity, r ₀ is the cross-sectional radius (inner diameter) of the converter near the hot metal surface, l ₀ is the measured value of the hot metal surface height by the _{microwave hot metal surface meter, and WT 0} is the measured value of the hot metal surface by the microwave hot metal surface meter. The amount of iron charged into the converter at the time of measurement, WTn is the amount of iron charged into the converter when calculating the estimated hot metal surface height.

However, since the refractory material stuck to the inner surface of the converter is repeatedly worn and repaired, the radius of gyration of the converter changes with each blowing. For this reason, there is a discrepancy between the estimated hot metal surface height and the actual hot metal surface height every time the hot metal surface height is measured by the microwave hot metal surface meter and the blowing is repeated. This made it impossible to set the lance gap to the optimum interval.

The present disclosure has been made in view of such circumstances, and an object of the present invention is to provide a converter blowing method capable of performing blowing with an appropriate lance gap even when the height of the hot metal surface is not actually measured.

The present disclosers have found the following findings as a result of diligent studies on a method of setting an optimum lance gap in a method of charging a top-blown lance into a converter and performing blowing.
The lance gap can be estimated from the dust generation rate by utilizing the fact that the dust generation rate changes due to the fluctuation of the lance gap.
However, as the number of times the top-blown lance is used increases, the flow of oxygen gas (oxygen jet) injected due to the deformation of the lance (nozzle shape) changes, so the dust generation rate changes even if the lance gap is constant. .. That is, it is difficult to estimate the lance gap only from the dust generation rate.
Therefore, the lance gap is adjusted based on the dust generation rate in consideration of the influence of the number of times the lance is used.
This disclosure is based on the above findings, and the summary is as follows.

The converter blowing method of one aspect of the present disclosure is a converter blowing method in which oxygen gas is blown from a nozzle of a top blowing lance to a hot metal surface in a converter, and the amount of dust in exhaust gas generated during blowing. The above Relationship between the number of times the blow lance is used and the dust generation rate The deviation amount calculation step for obtaining the deviation amount of the dust generation rate calculated in the speed calculation step with respect to R1, the deviation amount calculation step for obtaining the deviation amount of the dust generation rate, and the change amount of the lance gap and the said It has a position adjusting step of adjusting the lance gap during the blowing in order to correct the deviation amount obtained in the deviation amount calculation step from the relationship R2 with the change amount of the dust generation rate.

According to the present disclosure, it is possible to provide a converter blowing method capable of performing blowing with an appropriate lance gap even when the height of the hot metal surface is not actually measured.

It is explanatory drawing of the refining equipment to which the converter blowing method which concerns on one Embodiment of this disclosure is applied. It is explanatory drawing of the dust concentration measuring apparatus of the refining equipment shown in FIG. 1A. It is sectional drawing of the tip side of the top blowing lance used in the refining equipment shown in FIG. 1A. FIG. 2 is a cross-sectional view of the tip side of the top blow lance showing a state in which the nozzle is worn due to use in the top blow lance shown in FIG. 2A. It is a graph which shows the relationship between the change amount of the lance gap and the change amount of the dust generation rate in a converter at each use of the top blowing lance. It is a graph which shows the relationship between the number of times of use of the top blowing lance and the dust generation rate in a converter when the lance gap is set to the optimum interval.

Hereinafter, one embodiment of the present disclosure will be described with reference to the drawings.

The converter blowing method according to the embodiment of the present disclosure is the blowing method used in the refining equipment 9 shown in FIGS. 1A and 1B. First, the refining equipment 9 of the present embodiment will be described, and then the converter blowing method of the present embodiment will be described.

As shown in FIGS. 1A and 1B, the refining facility 9 includes a converter 10, a top-blown lance 11 (hereinafter, appropriately referred to as “lance”), and an exhaust gas treatment device 17.

As shown in FIG. 2A, the lance 11 is a member for blowing oxygen gas from the nozzle 11A, which will be described later, onto the hot metal surface S in the converter 10. The lance 11 has a cylindrical shape and can be moved upward and downward in the vertical direction by an elevating device (not shown). By moving the lance 11 up and down, the lower part (tip side) of the lance 11 can be inserted or removed from the converter 10. Further, the lance 11 can be stopped at an arbitrary height position by an elevating device. The lance gap G, which will be described later, can be adjusted by the vertical movement of the lance 11. The arrow UP in FIG. 2A indicates an upward direction in the vertical direction. Further, the arrow AXL in FIG. 2A indicates the central axis of the lance 11.

Further, the tip portion of the lance 11 is a nozzle portion, and a plurality of nozzles 11A are provided in this nozzle portion. These nozzles 11A are through holes having a narrowed intermediate portion, that is, de Laval nozzles, and a plurality of these nozzles 11A are provided at regular intervals on a concentric circle centered on the central axis AXL of the lance 11. There is. The nozzle 11A may also be formed on the central axis AXL of the lance 11.

As shown in FIG. 2A, the oxygen gas A supplied to the lance 11 is injected from the nozzle 11A. Here, the jet of oxygen gas A injected from the nozzle 11A toward the hot metal surface S forms a jet core, then spreads at an angle with a free spreading angle of φ, and collides with the hot metal in the converter 10. A waterfall-shaped concave fire point is formed on the hot metal surface S (note that the fire point is not shown in FIG. 2A).

As shown in FIG. 1A, the exhaust gas treatment device 17 is a device for wetly treating exhaust gas (gas containing CO, CO ₂ , N ₂ gas as a main component) containing dust generated from the converter 10. The exhaust gas treatment device 17 includes a hearth hood 18, an exhaust gas duct 12, a primary dust collector 13, a secondary dust collector 19, and the like.

The hearth hood 18 and the exhaust gas duct 12 are provided above the converter 10. Further, on the downstream side of the exhaust gas duct 12, a primary dust collector 13, a secondary dust collector 19, and an attracting blower (not shown) are sequentially provided. The exhaust gas from the converter 10 is sucked by the attracting blower, passed through the furnace mouth hood 18 and the exhaust gas duct 12, and is removed by the primary dust collector 13 and the secondary dust collector 19. Furthermore, the dust-removed exhaust gas is sent to a gas holder (not shown) as a valuable gas via an attracting blower, while the exhaust gas with a low CO concentration is burned at the top through a chimney (not shown) in the atmosphere. Is radiated to.

The primary dust collector 13 and the secondary dust collector 19 each collect exhaust gas in a wet manner, and for example, a Venturi scrubber is used.

The dust collecting water introduced into the primary dust collector 13 (indicated by the arrow W in FIGS. 1A and 1B) takes in the dust in the exhaust gas and becomes the dust collecting water containing the dust. The dust collecting water is temporarily stored in a lower water tank 14 provided directly under the primary dust collector 13, and then sent to a dust collecting water treatment device (not shown) to remove dust in the dust collecting water.

Further, as shown in FIG. 1B, the exhaust gas treatment device 17 includes a dust concentration measuring device (hereinafter, appropriately referred to as “measuring device”) 20 for measuring the dust concentration. The measuring device 20 includes a pump 15 that continuously collects the dust collected water that has passed through the primary dust collector 13, and a vibration densitometer 16 for measuring the density of the dust collected water. In this measuring device 20, the dust collecting water is continuously collected by the pump 15, and the dust concentration in the dust collecting water per unit time is continuously measured by using the vibration type densitometer 16 in relation to the water temperature at that time. (The amount of dust in the exhaust gas generated during the blowing of the converter 10 is continuously measured). Here, most of the dust generated in the converter 10, at least 90% or more, is removed by the primary dust collector 13. Therefore, the dust concentration in the exhaust gas of the converter 10 can be estimated by measuring the dust concentration in the dust collecting water collected by the primary dust collector 13.
The dust collected water after the dust concentration measurement is returned to the lower water tank 14.

Next, the converter blowing method of the present embodiment will be described.
In the converter blowing method of the present embodiment, as shown in FIGS. 1A and 1B, the tip end side of the lance 11 is inserted into the converter 10, and the hot metal surface S in the converter 10 is inserted from the nozzle 11A of the lance 11. This is a blowing method in which oxygen gas A is sprayed on the surface to decarburize. Then, this converter blowing method is characterized in that the lance gap G (see FIG. 2A), which is the distance between the hot metal surface S and the tip of the lance 11, is set to the optimum interval when the blowing is performed. The blowing is not limited to top blowing, but top blowing may be used in combination with bottom blowing.

Specifically, the above-mentioned converter blowing method includes a speed calculation step of calculating the dust generation rate GR by obtaining the amount of dust in the exhaust gas generated during blowing.
The deviation amount calculation for obtaining the deviation amount of the dust generation speed GR calculated in the speed calculation process with respect to the relationship R1 between the number of times the lance 11 is used and the dust generation speed GR when the lance gap G is set to the optimum interval, which is obtained in advance. Process and
The lance gap G is adjusted during the above-mentioned blowing in order to correct the deviation amount obtained in the deviation amount calculation step from the relationship R2 between the change amount of the lance gap G and the change amount of the dust generation rate GR obtained in advance. Position adjustment process and
It is a method having.

The speed calculation step, the deviation amount calculation step, and the position adjustment step described above are processed by the computer (calculation means) of the operator who operates the converter. Further, the relation R1 used in the deviation amount calculation step and the relation R2 used in the position adjustment step are stored in a database, for example. The above-mentioned computer receives various information for performing the converter operation, and also controls the converter operation (for example, start and stop of blowing, adjustment of the lance gap G) (that is, the computer controls it). Means).
The computer described above is a conventionally known computer provided with a RAM, a CPU, a ROM, an I / O, and a bus for connecting these elements, but the computer is not limited thereto.

First, each calculation method of the dust generation rate, the relation R1 and the relation R2 described above will be described.

In the converter operation, as shown in FIG. 1A, a lance 11 is inserted into the furnace from above the converter 10, and oxygen gas A is blown onto the hot metal at high speed to cause impurities such as Si, C, P, and Mn. Is removed (decarburized). At that time, fine dust is generated due to the rebound of the blown oxygen gas A on the hot metal surface S and the defoaming of the CO gas on the hot metal surface S due to the decarburization reaction.
The generated dust is sucked into the exhaust gas duct 12 through the furnace mouth hood 18 together with the exhaust gas generated from the converter 10, and is contained in the dust collecting water supplied from the primary dust collector 13, and is collected through the lower water tank 14. It is sent to the processing equipment and separated and collected. By spraying the dust collected water by the primary dust collector 13, the dust generated from the converter 10 is separated from the exhaust gas, and the exhaust gas is sent to the downstream side.

(Calculation method of dust generation rate in converter 10)
As shown in FIG. 1B, in the measuring device 20, the dust collecting water is continuously collected by the pump 15, and the dust collecting water per unit time is collected by using the vibration type densitometer 16 in relation to the water temperature at that time. Perform continuous measurement of dust concentration. The dust generation rate during blowing of the converter 10 can be calculated from the product of the dust concentration measured by the above method and the amount of dust collected per unit time (the amount of water sprayed from the primary dust collector 13).

(Calculation method of relation R2)
The hot metal surface S in the converter 10 (for example, the amount of hot metal in the converter is about 400 tons) is measured by a microwave hot metal level gauge (not shown), and the lance gap G for each use of the lance 11 and the removal of acid are removed. Estimating the relationship with the average dust generation rate GR in the peak decarburization period, which is the time when coal preferentially occurs, the relationship shown in FIG. 3 can be obtained. The number of times N of the lance 11 is used corresponds to the number of times of blowing of the converter 10 (the same applies hereinafter). In FIG. 3, the lance is used about 50 times (when the number of times of use is small: the black circle in FIG. 3) and when the lance is used about 200 times (when the number of times of use is large: the white circle in FIG. 3). ) Is shown, but the same behavior is shown even within the range of 50 to 200 times.
As shown in FIG. 3, the dust generation rate GR increases linearly with the increase of the lance gap G (here, in the range of 2500 to 3000 mm), and the relationship is associated with the increase of the number of times the lance is used N. The inclination is constant regardless of the deformation of the nozzle 11A of the lance 11. The "slope" referred to here is a gradient obtained by dividing the amount of change in the dust generation rate GR by the amount of change in the lance gap G (that is, the relationship R2).

(Calculation method of relationship R1)
When the hot metal surface S in the converter 10 is measured by a microwave hot metal level gauge and the lance gap G is set to the optimum interval, the dust generation rate GR at the peak of decarburization with respect to the number of times the lance is used N is shown in FIG. It becomes a relationship (that is, a relationship R1).
As shown in FIG. 4, when the lance gap G is set to the optimum value, the dust generation rate GR increases as the number of times the lance is used N increases. Incidentally, the curve shown in FIG. 4, the dust generation rate and y, has the lance usage count and ^{x, y =} 6.9492x ^0.0698, and.

The dust generation rate GR of the converter 10 is calculated by the above method, and the speed calculation step, the deviation amount calculation step, and the position adjustment step are sequentially performed using the relation R1 and the relation R2 obtained in advance.

(Speed calculation process)
First, based on the estimated hot metal surface height obtained by the above equation (1), the lance height is set so as to have an optimum lance gap G, and the converter 10 is blown, and the above-mentioned blowing is performed. Using the smelting method, the average dust generation amount (dust amount) in the exhaust gas generated at the peak of decarburization is obtained, and the dust generation rate GR of the converter 10 is calculated.

(Displacement amount calculation process)
Dust generation of the converter 10 calculated in the speed calculation step from the relationship R1 between the number of times the top-blown lance 11 is used in the optimum lance gap and the dust generation speed of the converter 10 shown in FIG. 4 described above. Find out how much the speed GR is off. Specifically, the difference (that is, the amount of deviation) between the value of the dust generation speed GR obtained from FIG. 4 and the value of the dust generation speed calculated in the speed calculation step is obtained according to the number of times the lance is used N.
Here, when the calculated value of the dust generation speed GR is lower than the value of the dust generation speed GR according to the number of times N of lances used shown in FIG. 4, the actual lance gap G is smaller than the optimum lance gap G. Since it indicates that it is small (hard blow), it is necessary to adjust the lance gap G to a large extent. On the other hand, when the calculated value of the dust generation speed GR is higher than the value of the dust generation speed GR according to the number of times N of lances used shown in FIG. 4, the actual lance gap G is larger than the optimum lance gap G. Since it indicates (soft blow), it is necessary to adjust the lance gap G to be small.

(Position adjustment process)
In order to correct the deviation amount obtained in the deviation amount calculation step from the relationship R2 between the change amount of the lance gap G and the change amount of the dust generation rate GR, which is shown in FIG. Adjust the lance gap G. In the present embodiment, the dust generation rate GR is obtained and the lance gap G is adjusted during the peak period of decarburization by blowing.

As described above, the gradient obtained by dividing the amount of change in the dust generation rate GR by the amount of change in the lance gap G, which indicates the relationship R2 between the amount of change in the lance gap G and the amount of change in the dust generation rate GR, is the number of times the lance is used N. It is almost constant regardless. From the relationship between the two, the adjustment amount of the lance gap G for correcting the deviation amount of the dust generation rate GR is obtained, and the lance gap G is adjusted during the blowing of the converter 10.

Specifically, the deviation amount of the dust generation rate GR obtained in the deviation amount calculation step is divided by the above gradient to obtain the adjustment amount of the lance gap G corresponding to the deviation amount of the dust generation rate GR, and this adjustment is performed. The lance gap G is adjusted by changing the height position of the lance 11 by the amount.
The above-mentioned adjustment of the lance gap G (that is, the speed calculation step, the deviation amount calculation step, and the position adjustment step) may be performed once in one blowing, but may be performed a plurality of times as necessary. You can also do it.

Here, as shown in FIG. 2B, as the number of times N of use of the lance 11 increases, the outlet portion of the nozzle 11A tends to wear and the outlet diameter tends to increase. When the outlet diameter of the nozzle 11A is widened, energy loss occurs at the nozzle outlet and the jet core length is shortened, so that the momentum of the oxygen gas A is reduced. However, in the converter blowing method of the present embodiment, in order to adjust the lance gap G based on the dust generation rate GR in consideration of the influence of the number of times N of the lance 11 is used, the hot metal is melted by using a microwave hot metal surface meter. Even when the surface height is not actually measured, the converter 10 can be blown with an appropriate lance gap G. As a result, the amount of dust becomes excessive due to excessive soft blow (the lance gap G becomes large), and the life of the lance 11 becomes remarkable due to excessive hard blow (the lance gap G becomes small). It can be suppressed or even prevented from being lowered.

Next, an example carried out for confirming the action and effect of the present disclosure will be described.
Here, the results of applying the methods of Examples and Comparative Examples when blowing the converter under the conditions that the amount of hot metal is 400 tons and the optimum lance gap G is 3000 mm will be described.
It should be noted that the example is a result of sequentially performing the speed calculation step, the deviation amount calculation step, and the position adjustment step of the above-described embodiment of the present disclosure, and adjusting the lance gap G according to the dust generation speed GR. The example is the result of adjusting the lance gap based on the estimated hot metal height obtained from the above equation (1).

The evaluation is the average value of the number of charges until water leakage from the lance occurs in the number of times (N = 10) of 10 trials (N = 10) in which the test for one lance is set to 1 (N = 1). This was performed using the life and the measured amount of dust generated (dust amount). The water leakage from the lance is caused by the water-cooled structure of the lance, and is caused by the wear of the lance due to long-term use. The amount of dust generated is obtained by adding the product of the dust concentration in the dust collecting water measured by the dust concentration measuring device and the amount of water sprinkled per unit time (1 second) of the dust collecting water through one charge to obtain hot metal. The value was divided by the amount of 400 tons.
The average lifespan was about 300 charges in the examples compared to 250 charges in the comparative example, which was superior to 50 charges.
The amount of dust generated could be reduced by 0.3 to 0.7 kg / ton in the example with the average value of the test charge for one lance, as compared with the average value of 15 kg / ton of all the test charges in the comparative example.

From the above, it was confirmed that by applying the converter blowing method of the present disclosure, blowing can be performed with an appropriate lance gap, and the amount of dust generated can be reduced while maintaining the life of the lance.

Although the present disclosure has been described above with reference to the embodiments, the present disclosure is not limited to the configuration described in the above-described embodiments, and the matters described in the claims. It also includes other embodiments and variations that may be considered within the scope. For example, the case where a part or all of the above-described embodiments and modifications are combined to form the converter blowing method of the present disclosure is also included in the scope of rights of the present disclosure.

In the above-described embodiment, the case where the approximate expressions calculated from the data of the past operation results are used for the relation R1 and the relation R2, respectively, has been described, but the present invention is not limited to this, and for example, the past operation. You may use the data in the database which is the actual result.

Further, in the above-described embodiment, a gradient obtained by dividing the amount of change in the dust generation rate of the converter by the amount of change in the lance gap G was used to correct the amount of deviation. This gradient is used based on the fact that it is constant regardless of the number of times the lance is used, but for example, the amount of deviation can be corrected by using the gradient obtained for each number of times the lance is used.

Further, in the above-described embodiment, the measuring device 20 includes a pump 15 and a vibrating densitometer 16, continuously collects dust collected water by the pump 15, and uses the vibrating densitometer 16 at that time. The amount of dust is determined by continuously measuring the dust concentration in the dust collecting water per unit time in relation to the water temperature, but the present invention is not limited to this configuration. For example, the measuring device 20 is further equipped with a thermometer, and the dust-collected water obtained by wet-collecting the exhaust gas is continuously collected, passed through the vibrating densitometer 16 and the thermometer, and measured by the vibrating densitometer 16. The dust concentration in the dust collecting water may be calculated from the difference between the density of the dust collected water and the density of pure water predicted from the temperature of the dust collected water measured by the thermometer to obtain the dust amount. Specifically, the dust concentration is calculated using the following formula (2). The unit of concentration or density in the following formula (2) ^{may be kg / m 3} of the present embodiment, or may be g / L or kg / L.
C = (ρmeasure-ρwater) × ρdust / (ρdust-ρwater) ・ ・ ・ (2)
However, C: dust concentration (kg / m ³ ), ρ measure: density of dust collected water measured by the vibration densitometer 16 (kg / m ³ ), ρ water: predicted from the temperature of dust collected water measured by a thermometer. Density of pure water (kg / m ³ ), ρ dust: Density of dust particles (for example, 7800 kg / m ³ ).
Either the vibration type densitometer 16 or the thermometer may be upstream or downstream.
For example, when a dust concentration measuring device using ultrasonic waves or light is used, the dust concentration is estimated from the attenuation rate, so that it is affected by the dust particle size. , The density of dust in the dust collecting water, that is, the mass can be directly measured, and is not affected by the dust particle size. Therefore, the dust concentration in the dust collecting water can be measured accurately and accurately. As a result, the converter 10 can be blown with a more appropriate lance gap G.

Regarding the above embodiments, the following additional notes will be further disclosed.

(Appendix 1)
In the method of charging the top blowing lance into the converter and performing blowing,
A speed calculation process for calculating the dust generation rate by measuring the amount of dust in the exhaust gas generated during the blowing of the converter, and
The number of times the top-blown lance is used and the dust generation rate of the converter when the lance gap, which is the distance between the molten metal surface in the converter and the tip of the top-blown lance, is set to the optimum interval, which is obtained in advance. The deviation amount calculation step for obtaining the deviation amount of the dust generation rate of the converter calculated in the speed calculation step with respect to R1
In order to correct the deviation amount obtained in the deviation amount calculation step from the relationship R2 between the change amount of the lance gap and the change amount of the dust generation rate of the converter obtained in advance, the converter blown. A converter blowing method comprising a position adjusting step for adjusting the lance gap inside.

(Appendix 2)
In the converter blowing method described in Appendix 1, the converter blowing is characterized in that a gradient obtained by dividing the change amount of the dust generation rate of the converter by the change amount of the lance gap is used to correct the deviation amount. How to smelt.

In the above-mentioned converter blowing method, the relationship between the number of times the top-blown lance is used and the dust generation rate when the lance gap is set to the optimum interval in the shift amount calculation step. Since the lance gap is adjusted so as to correct the deviation amount obtained in the deviation amount calculation process from the relationship R2 between the lance gap and each change amount of the dust generation rate in the position adjustment process after obtaining the deviation amount, an appropriate lance gap is obtained. You can carry out the smelting at.
As a result, the amount of dust becomes excessive due to excessive soft blow (the lance gap becomes large), and the life of the top blow lance is significantly shortened due to excessive hard blow (the lance gap becomes small). It can be suppressed or even prevented from being caused.

All documents, patent applications, and technical standards described herein are to the same extent as if the individual documents, patent applications, and technical standards were specifically and individually stated to be incorporated by reference. Incorporated herein by reference.

10 converter 11 top blown lance 11A nozzle 16 vibration type densitometer (density meter)
G lance gap GR dust generation speed N lance usage count

Claims (3)

It is a converter blowing method that blows oxygen gas from the nozzle of the top blowing lance to the hot metal surface in the converter.
A speed calculation process for calculating the dust generation rate in the converter by obtaining the amount of dust in the exhaust gas generated during blowing, and
The speed with respect to the relationship R1 between the number of times the top blowing lance is used and the dust generation rate when the lance gap, which is the distance between the hot metal surface and the tip of the top blowing lance, is set to the optimum interval. The deviation amount calculation process for obtaining the deviation amount of the dust generation rate calculated in the calculation process, and
In order to correct the deviation amount obtained in the deviation amount calculation step from the relationship R2 between the change amount of the lance gap and the change amount of the dust generation rate obtained in advance, the lance gap is formed during the blowing. Position adjustment process to adjust and
A converter blowing method with. The converter blowing method according to claim 1, wherein a gradient obtained by dividing the amount of change in the dust generation rate by the amount of change in the lance gap is used to correct the amount of deviation. In the speed calculation step, the dust-collected water obtained by wet-collecting the exhaust gas is continuously collected, passed through a densitometer and a thermometer, and the density of the dust-collected water measured by the densitometer is measured by the thermometer. The converter blowing method according to claim 1 or 2, wherein the dust concentration in the dust collecting water is calculated from the difference from the density of pure water predicted from the temperature of the collected dust water to obtain the dust amount. ..

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