JP6973339B2 - Refining lance equipment - Google Patents

Description

The present invention relates to a refining lance facility used for refining molten iron (hot metal, molten steel) in the metallurgical field, and a method for suppressing vibration of a lance using the refining lance facility.

The refining treatment of the hot metal is performed by injecting oxygen or an oxidizing agent into the hot metal from the lance in a state where the lance is immersed in the hot metal transport container containing the hot metal. In this treatment, for the purpose of improving the desiliconization and dephosphorization efficiency, the amount of oxygen and oxidant blown from the lance is adjusted, and the stirring efficiency is improved by using a plurality of lances. On the other hand, when oxygen or an oxidizing agent is blown from the lance, the lance vibrates due to these blowings, which causes a problem that the lance breaks in a short period of time.

When oxygen or an oxidizer is blown into the hot metal from the lance, a vortex flow is generated in the hot metal. When the frequency of the vortex generated in the hot metal and the natural frequency of the lance match, self-excited vibration occurs in the lance. Since the stress generated in the lance by the self-excited vibration becomes large, it is necessary to suppress the self-excited vibration due to this vortex flow so that the stress generated by the self-excited vibration becomes less than the allowable value when designing the lance.

In Patent Document 1, an iron blade plate is provided at the upper end of a refining blowing lance, and the iron blade plate is sandwiched between a guide roll provided on a vibration prevention jig and an iron blade receiver, whereby the refining blowing is performed. A refining blown lance facility that suppresses vertical vibration of the lance is disclosed.

Japanese Unexamined Patent Publication No. 2007-231342

The natural vibration of the refining lance has multiple vibration modes. Then, self-excited vibration corresponding to the vibration of the vibration mode different depending on the amount of oxygen or oxidant blown from the refining lance is generated. In Patent Document 1, since the vibration is suppressed by sandwiching the iron blade plate between the guide roll and the iron blade receiver, the stress generated by the self-excited vibration in different vibration modes cannot be efficiently suppressed. The present invention has been made in view of the above problems, and an object thereof is a lance equipment for refining that can efficiently suppress stress generated by self-excited vibration of a lance, and vibration control of a lance using the lance equipment for refining. Is to provide a method.

The features of the present invention for solving such a problem are as follows.
(1) A refining lance facility used for refining molten iron, in which a lance for blowing at least one of an oxidizing agent and a refining agent into the molten iron together with a transport gas, and a space inside are provided around the lance. The fluid has a damper, a fluid filled in the damper, a support for supporting the damper, an actuator for changing the pressure of the fluid, and a control device for controlling the actuator. A refining lance facility in which the holding force of the lance by the damper changes when the pressure is changed.
(2) The refining lance facility according to (1), further comprising a vibration sensor for measuring the vibration of the lance.
(3) A lance damping method using the refining lance equipment according to (1) or (2).
A method of damping a lance that changes the pressure of the fluid according to the amount of blown air from the lance.
(4) A method of damping a lance using the refining lance equipment according to (2), wherein the pressure of the fluid is changed so that the vibration of the lance is reduced.

Since the refining lance facility of the present invention can change the pressure of the fluid of the damper corresponding to each vibration mode, the stress generated by the self-excited vibration corresponding to each vibration mode can be efficiently suppressed. As a result, it is possible to prevent the lance from breaking in a short period of time.

It is a partial cross-sectional schematic diagram which shows the state which dephosphorized the hot metal 14 housed in the torpedo wagon 10 by using the refining lance equipment 20 which concerns on this embodiment. It is a partial cross-sectional schematic diagram of the refining lance equipment 20. It is a graph which shows the fluctuation of the stress generated in the lance 22.

Hereinafter, the present invention will be described in detail through embodiments of the present invention. FIG. 1 is a schematic partial cross-sectional view showing a state in which the hot metal 14 housed in the torpedo wagon 10 is dephosphorized using the refining lance facility 20 according to the present embodiment. In FIG. 1, only the torpedo wagon 10 is shown in a cross-sectional view in order to explain the operation of the refining lance facility 20 according to the present embodiment. The present embodiment will be described with reference to an example in which the hot metal is dephosphorized using the refining lance equipment according to the present invention, but the present invention is not limited to this, and the refining lance equipment according to the present invention is a molten iron (hot metal). , Including molten steel) can also be used for desiliconization treatment or decarburization treatment.

The torpedo wagon 10 has a transport container 12. The hot metal 14 ejected from the blast furnace is housed in the transport container 12. After the hot metal 14 is housed in the transport container 12, the lance tip portion of the refining lance facility 20 is immersed in the hot metal 14, and the hot metal 14 is dephosphorized in this state. A predetermined amount of oxidizing agent and dephosphorizing agent was blown from the refining lance facility 20, and the hot metal 14 having a phosphorus concentration equal to or lower than the target was equipped with a steelmaking smelting furnace (converter) by a torpedo wagon 10. Transported to a steel factory.

The refining lance facility 20 is inserted from the opening of the transport container 12 in an oblique direction with respect to the vertical direction, and the lance 22 is held in a state of being immersed in the hot metal 14. A dephosphorizing agent containing iron oxide, which is an oxidizing agent, and a CaO-containing substance is blown into the hot metal 14 together with the transport gas from the lance 22. As the oxidizing agent blown from the lance 22 to the hot metal 14, an iron oxide source such as iron ore, sintered ore, or mill scale can be used. Further, as the transport gas, gaseous oxygen, air, nitrogen, a rare gas or the like can be used.

When an oxidizing agent, a dephosphorizing agent, or the like is blown into the hot metal 14 from the lance 22, a vortex flow is generated in the hot metal 14 by the blowing oxidizing agent, the dephosphorizing agent, or the like. Self-excited vibration occurs when the frequency of the vortex of the vortex flow generated in the hot metal 14 and the natural frequency of the lance 22 match. When self-excited vibration occurs in the lance 22 for a long period of time, the lance 22 breaks due to the stress generated by the self-excited vibration. Therefore, the refining lance facility 20 according to the present embodiment has a configuration for suppressing the stress generated by the self-excited vibration of the lance 22.

FIG. 2 is a schematic partial cross-sectional view of the refining lance facility 20. The refining lance facility 20 includes a lance 22, a support 24, an elevating device 25, a hydraulic damper 26, a hydraulic cylinder 30, an acceleration sensor 32, a control device 34, and a clamp 36. In FIG. 2, in order to explain the configuration of the refining lance equipment 20, the configurations other than the lance 22 and the clamp 36 are shown in cross section.

The lance 22 is provided with a refractory coating layer made of an amorphous refractory material on the outside, and has a single pipe or double pipe structure inside. The support body 24 is a cylindrical member and supports the hydraulic damper 26. A part of the outer peripheral surface of the support 24 is fixed to the elevating device 25, and the hydraulic damper 26 is fixed to the inside. The elevating device 25 is movable in an oblique direction with respect to the direct direction, and controls the immersion depth of the lance 22 in the hot metal 14. A support 24 and a clamp 36 are fixed to the elevating device 25.

The hydraulic damper 26 is provided so as to surround the lance 22 so as to hold the periphery of the lance 22. A space filled with oil 28 is provided inside the hydraulic damper 26, and when the pressure of the oil 28 is changed, the holding force of the lance 22 by the hydraulic damper 26 in the circumferential direction changes. That is, when the pressure of the oil 28 is increased, the holding force of the lance 22 is increased, and when the pressure of the oil 28 is decreased, the holding force of the lance 22 is weakened. In this embodiment, an example using the hydraulic damper 26 filled with oil 28 is shown, but the oil 28 is an example of a fluid, and for example, a damper filled with a gas such as air may be used. , A damper filled with a liquid different from oil may be used.

The hydraulic cylinder 30 controls the oil pressure of the hydraulic damper 26 to a predetermined oil pressure by the control of the control device 34. The hydraulic cylinder 30 is an example of an actuator, and instead of the hydraulic cylinder 30, another actuator such as a pneumatic cylinder, a hydraulic cylinder, or a motor may be used.

The acceleration sensor 32 measures the vibration frequency and acceleration generated by the vibration of the lance 22. The acceleration sensor 32 is provided in the lance 22, measures the acceleration in the direction orthogonal to the axial direction of the lance 22 generated in the lance 22, records the measured acceleration signal, and performs high-speed Fourier transform processing on the acceleration signal. , The frequency analysis of the lance 22 is performed in real time to calculate the vibration frequency. The acceleration sensor 32 outputs an acceleration signal and a signal indicating a vibration frequency to the control device 34. The acceleration sensor 32 is an example of a vibration sensor that measures the vibration of the lance 22.

The control device 34 is, for example, a computer having a CPU and a recording device (HDD). A program for controlling the hydraulic cylinder 30, data used for executing the program, and a control signal for controlling the hydraulic cylinder 30 are recorded in advance in the recording device.

The control device 34 acquires a signal indicating the flow rate of the oxidizing agent or the refining agent blown from the lance 22. When the control device 34 acquires the signal indicating the blowing flow rate, the control device 34 outputs the control signal corresponding to the blowing flow rate to the hydraulic cylinder 30.

Further, when the control device 34 acquires a signal indicating the vibration frequency from the acceleration sensor 32, the control device 34 may output a control signal corresponding to the vibration frequency, and the acquired blowing flow rate and the vibration frequency may be used. , The control signal corresponding to the blowing flow rate recorded in the recording device may be corrected. Further, when the acceleration signal of the lance 22 is acquired from the acceleration sensor 32, the oil pressure of the hydraulic cylinder 30 may be dynamically controlled so that the acceleration becomes smaller. In this case, the control device 34 dynamically controls the pressure of the hydraulic cylinder 30 so that the acceleration acquired from the acceleration sensor 32 is minimized by using, for example, a hill climbing method.

The hydraulic cylinder 30 changes the oil pressure of the hydraulic damper 26. When the hydraulic cylinder 30 acquires a control signal from the control device 34, the hydraulic cylinder 30 adjusts the hydraulic pressure to operate the cylinder, and changes the hydraulic pressure of the hydraulic damper 26 to the hydraulic pressure corresponding to the control signal. The holding force of the lance 22 by the hydraulic damper 26 is adjusted by this change in the hydraulic pressure.

The hydraulic damper 26 is fixedly provided on the inner peripheral surface of the support 24. As described above, since the support 24 is fixed to the elevating device 25, when the holding force of the lance 22 by the hydraulic damper 26 is increased, the movement of the lance 22 in the circumferential direction is restricted. On the other hand, when the holding force of the lance 22 by the hydraulic damper 26 is weakened, the lance 22 is allowed to move in the circumferential direction.

The clamp 36 is fixedly provided to the elevating device 25 at the end opposite to the position where the hydraulic damper 26 is provided. The clamp 36 restricts the movement of the lance 22 in the axial direction and the circumferential direction.

The self-excited vibration of the lance 22 is generated by matching the natural frequency of the lance 22 with the frequency of the vortex of the vortex flow generated by the blowing of the oxidizing agent or the dephosphorization refining agent blown from the lance 22. The natural frequency of the lance 22 has a plurality of vibration modes such as a primary mode and a secondary mode, and self-excited vibration in various vibration modes may occur depending on the frequency of the vortex generated in the hot metal 14. In this way, where the self-excited vibration of various vibration modes can occur depending on the frequency of the vortex, the inventors have found that the self-excitation generated by matching the natural frequency of each mode in the lance 22 with the frequency of the vortex. It has been found that the holding force of the hydraulic damper 26 capable of efficiently suppressing vibration is different in each vibration mode.

FIG. 3 is a graph showing the stress generated in the lance 22. The vertical axis of FIG. 3 is the stress (MPa) generated in the lance 22 due to vibration, and the horizontal axis is the blowing flow rate (Nm ³ / min). Each profile shown in FIG. 3 increases the frequency of the vortex generated in the hot metal 14 by increasing the flow rate blown from the lance 22, and shows the fluctuation of the stress generated in the lance 22 due to the vibration caused by the vortex.

The solid line in FIG. 3 shows the fluctuation of the stress generated in the lance 22 when the refining lance facility without the hydraulic damper 26 is used. The peak in FIG. 3 is the stress generated in the lance 22 by the self-excited vibration of the natural frequency of the primary mode, the secondary mode, the tertiary mode, and the quaternary mode from the left side. As described above, it can be seen that the self-excited vibration corresponding to each natural frequency gives a large stress to the lance 22. From the solid line in FIG. 3, it can be seen that when the hydraulic damper 26 is not provided, the stress generated in the lance 22 due to vibration is larger than in other conditions where the hydraulic damper 26 is provided to increase the holding force of the lance 22. ..

The dotted line in FIG. 3 shows the fluctuation of the stress generated in the lance 22 when the hydraulic damper 26 is provided and the lance 22 is held by the hydraulic pressure of the damper condition 1. The oil pressure of the damper condition 1 is lower than that of the damper conditions 2 and 3.

As can be seen from the dotted line in FIG. 3, the stress generated in the lance 22 due to the self-excited vibration of the natural frequency of the primary mode and the secondary mode by setting the hydraulic pressure to the damper condition 1 is larger than that under the other damper conditions. It became smaller. On the other hand, the stress generated by the self-excited vibration of the natural frequency of the tertiary mode and the quaternary mode was larger when the hydraulic pressure was set to the damper condition 1 than when the other damper conditions were set.

The broken line in FIG. 3 shows the fluctuation of the stress generated in the lance 22 when the hydraulic damper 26 is provided and the lance 22 is held by the hydraulic pressure of the damper condition 2. The oil pressure of the damper condition 2 is higher than that of the damper condition 1 and lower than that of the damper condition 3.

As can be seen from the broken line in FIG. 3, the stress generated in the lance 22 due to the self-excited vibration of the natural frequency of the tertiary mode by setting the hydraulic pressure to the damper condition 2 became smaller than that under the other damper conditions. On the other hand, the stress generated in the lance 22 due to the self-excited vibration of the natural frequency of the primary mode, the secondary mode and the quaternary mode becomes larger when the hydraulic pressure is set to the damper condition 2 than when the other damper conditions are set. rice field.

The alternate long and short dash line in FIG. 3 shows the fluctuation of the stress generated in the lance 22 when the hydraulic damper 26 is provided and the lance 22 is held by the hydraulic pressure of the damper condition 3. The oil pressure of the damper condition 3 is higher than that of the damper conditions 1 and 2.

As can be seen from the alternate long and short dash line in FIG. 3, the stress generated in the lance 22 due to the self-excited vibration of the natural frequency of the quaternary mode by setting the hydraulic pressure to the damper condition 3 becomes smaller than that under the other damper conditions. rice field. On the other hand, the stress generated in the lance 22 due to the self-excited vibration of the natural frequency of the primary mode, the secondary mode and the tertiary mode became larger when the hydraulic pressure was set to the damper condition 3 than when the other damper conditions were set. ..

From these results, it can be seen that the holding force of the hydraulic damper 26 capable of efficiently suppressing the stress generated in the lance 22 due to the self-excited vibration of each natural frequency differs depending on each natural frequency. Therefore, the control device 34 acquires data indicating the flow rate of the oxidizing agent or the refining agent blown from the lance 22, and has a holding force capable of efficiently reducing the stress of self-excited vibration corresponding to the blowing flow rate. The control signal is output to the hydraulic cylinder 30. The hydraulic cylinder 30 changes the oil pressure so that the oil pressure of the hydraulic damper 26 becomes the holding force. As a result, the stress generated in the lance 22 due to the self-excited vibration of each natural frequency can be efficiently suppressed. Further, being able to suppress the stress generated in the lance 22 by the self-excited vibration means that the self-excited vibration generated in the lance 22 can be suppressed. Therefore, it can be said that the self-excited vibration generated in the lance 22 can be efficiently suppressed by using the refining lance facility 20 according to the present embodiment.

For example, when the flow rate from the lance 22 is 48 Nm ³ / min, the control device 34 outputs a control signal to the hydraulic cylinder 30 to set the hydraulic pressure to the damper condition 3. As a result, self-excited vibration corresponding to the natural frequency of the fourth mode generated in the lance 22 when the blowing flow rate is 48 Nm ^{3 / min can be efficiently suppressed.} Further, when the blowing flow rate is ^{changed from 48 Nm 3} / min to 12 Nm ³ / min, the control device 34 outputs a control signal to the hydraulic cylinder 30 to set the hydraulic pressure to the damper condition 1. As a result, self-excited vibration corresponding to the natural frequency of the secondary mode generated in the lance 22 when the blowing flow rate is 12 Nm ^{3 / min can be efficiently suppressed.}

The two-dot chain line in FIG. 3 shows the fluctuation of the stress generated in the lance 22 when the oil pressure of the hydraulic damper 26 is dynamically controlled so that the acceleration of the acceleration sensor 32 provided in the lance 22 is minimized. Minimizing the acceleration generated in the lance 22 by the vibration minimizes the amplitude of the lance 22 generated by the vibration. In this way, the hydraulic pressure of the hydraulic damper 26 is dynamically controlled so that the amplitude of the lance 22 due to vibration is minimized, so that the holding force of the hydraulic damper 26 is the holding force that can suppress the stress most in all the blowing amounts. Is controlled by. As a result, as can be seen from the two-dot chain line in FIG. 3, the stress generated in the lance 22 could be greatly suppressed at all the blowing amounts. By performing the same control while experimentally changing the amount of blown water from the lance 22, the oil pressure of the hydraulic damper 26 that can greatly suppress the stress corresponding to each amount of blown water can be obtained in advance.

Further, in the example shown in FIG. 3, an example is shown in which the control device 34 acquires data indicating the flow rate of the oxidizing agent or the refining agent blown from the lance 22 and outputs a control signal corresponding to the flow rate to the hydraulic cylinder 30. However, it is not limited to this. As described above, when the vibration frequency of the lance 22 is acquired from the acceleration sensor 32, the control signal corresponding to the vibration frequency may be output to the hydraulic cylinder 30. By acquiring the oil pressure of the hydraulic damper 26 that can efficiently suppress the vibration of each vibration frequency in advance, the control device 34 controls to efficiently suppress the vibration of the lance 22 corresponding to the acquired natural frequency. The signal can be output to the hydraulic cylinder 30.

Further, in the example shown in FIG. 2, the refining lance facility 20 having the acceleration sensor 32 is shown, but the present invention is not limited to this. When the control device 34 acquires data indicating the flow rate of the oxidizing agent or the refining agent blown from the lance 22 and outputs a control signal corresponding to the flow rate to the hydraulic cylinder 30, the refining lance facility 20 does not necessarily have to be. It is not necessary to have the acceleration sensor 32.

10 Torpedo wagon 12 Conveyor container 14 Hot metal 20 Refining lance equipment 22 Lance 24 Support 25 Lifting device 26 Hydraulic damper 28 Oil 30 Hydraulic cylinder 32 Accelerometer 34 Control device 36 Clamp

Claims (1)

A lance facility for refining used for refining molten iron.
A lance that blows at least one of the oxidizing agent and the refining agent into the molten iron together with the transport gas.
A space is provided inside, and the damper provided around the lance and
The fluid filled in the damper and
A support that supports the damper and
An accelerometer provided on the lance and measuring the acceleration in the direction orthogonal to the axial direction of the lance,
An actuator that changes the pressure of the fluid and
A control device that controls the actuator using the acceleration measured by the acceleration sensor, and
Have,
A lance facility for refining in which the holding force of the lance by the damper changes when the pressure of the fluid is changed.

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