阅读说明：本技术 一种喷粉装置、用于转炉底吹喷粉的喷粉装置及喷粉方法 (Powder spraying device, powder spraying device for converter bottom blowing powder spraying and powder spraying method ) 是由 朱荣 胡绍岩 苏荣芳 王洪 于 2020-06-02 设计创作，主要内容包括：本发明提供一种喷粉装置、用于转炉底吹喷粉的喷粉装置及喷粉方法,喷粉装置包括喷粉罐,喷粉罐分别连接增压气源、粉料仓和除尘器；喷粉罐下部为锥形段,锥形段连接锥形段气源；锥形段的底部、流化装置、粉料切断阀、流化装置、粉料调节阀、喷粉机构依次顺序连接。用于转炉底吹喷粉的喷粉装置包括喷粉装置,喷粉装置的喷粉机构通过输粉管道连接分配器,输粉管道上设置有粉剂流量计,分配器连接底吹喷嘴。喷粉方法包括加粉过程、喷粉过程和停粉过程。喷粉装置喷出的粉气流的状态稳定,避免粉气流的突然大幅波动,喷粉效果好,适用于转炉底吹喷粉工艺的复杂工况。应用喷粉方法喷粉,粉气流稳定性佳,喷粉过程安全稳定,喷粉效果好。(The invention provides a powder spraying device, a powder spraying device for bottom blowing powder spraying of a converter and a powder spraying method, wherein the powder spraying device comprises a powder spraying tank, and the powder spraying tank is respectively connected with a pressurized gas source, a powder bin and a dust remover; the lower part of the powder spraying tank is a conical section, and the conical section is connected with a conical section gas source; the bottom of the conical section, the fluidizing device, the powder cut-off valve, the fluidizing device, the powder regulating valve and the powder spraying mechanism are sequentially connected. The powder spraying device for the bottom blowing powder spraying of the converter comprises a powder spraying device, a powder spraying mechanism of the powder spraying device is connected with a distributor through a powder conveying pipeline, a powder flowmeter is arranged on the powder conveying pipeline, and the distributor is connected with a bottom blowing nozzle. The powder spraying method comprises a powder adding process, a powder spraying process and a powder stopping process. The powder flow sprayed by the powder spraying device is stable in state, avoids sudden large fluctuation of the powder flow, has good powder spraying effect, and is suitable for complex working conditions of a converter bottom blowing powder spraying process. The powder spraying method is applied to powder spraying, the powder airflow stability is good, the powder spraying process is safe and stable, and the powder spraying effect is good.)

1. A powder spraying device is characterized by comprising a powder spraying tank, wherein the powder spraying tank is respectively connected with a pressurized gas source, a powder bin and a dust remover;

the lower part of the powder spraying tank is a conical section, and the conical section is connected with a conical section gas source;

the bottom of the conical section, the fluidizing device, the powder cut-off valve, the fluidizing device, the powder regulating valve and the powder spraying mechanism are sequentially connected.

2. A powder spray device as claimed in claim 1, in which the powder spray means comprises a powder jet connected to the powder conditioning valve, the powder jet being connected to a source of powder carrier gas.

3. A powder spraying device as claimed in claim 1, in which the fluidising means comprises a fluidising section and a source of fluidising gas connected to the fluidising section, the fluidising section being connected between the conical section and the powder shut-off valve, and the fluidising section being connected between the powder shut-off valve and the powder regulating valve.

4. A powder spraying device as claimed in claim 1, which further comprises a pressure measuring means in the powder spray canister, the pressure measuring means being located on the powder spray canister.

5. A powder spraying device as claimed in claim 2, in which the powder jet applicator is further provided with an applicator pressure measuring device.

6. The powder spraying device for bottom blowing powder spraying of the converter is characterized by comprising the powder spraying device, wherein the powder spraying mechanism of the powder spraying device is connected with a distributor through a powder conveying pipeline, a powder flowmeter is arranged on the powder conveying pipeline, and the distributor is connected with a bottom blowing nozzle.

7. The powder spraying method is characterized by comprising a powder adding process, a powder spraying process and a powder stopping process;

in the powder adding process, a dust remover, a conical section gas source and a fluidizing device connected with the bottom end of the conical section are opened, the conical section gas source and the gas flow of the fluidizing device are all in a low flow mode, other equipment is in a closed state, after the pressure in a powder spraying tank is continuously lower than 0.05MPa for 10 seconds, a powder bin is opened, flowing powder enters the powder spraying tank, when the weight of the powder in the powder spraying tank reaches a preset value, the powder bin and the dust remover are closed, a pressurizing gas source is opened, and the pressure in the powder spraying tank is kept at the preset value;

in the powder spraying process, a powder regulating valve, a fluidizing device connected with the powder regulating valve and a powder cut-off valve are opened in sequence, the powder regulating valve is at the minimum powder outlet opening, and the gas flow of the fluidizing device executes a low flow mode; measuring the flow of powder sprayed by the powder spraying mechanism and judging whether the powder is discharged normally; normally discharging powder, slowly increasing the opening of a powder regulating valve, and keeping the opening of the powder regulating valve unchanged when the flow of the sprayed powder reaches a set value; abnormal powder discharging, executing a powder spraying adjusting method, measuring the flow of powder sprayed by a powder spraying mechanism, judging whether the powder is discharged normally, and repeating the operation;

and in the powder stopping process, after the powder spraying amount reaches the process requirement, the opening degree of a powder regulating valve is slowly reduced to the minimum powder outlet opening degree, then a powder stop valve is closed, the powder regulating valve is slowly increased to the maximum opening degree, the gas flow of a fluidizing device connected with the powder regulating valve is increased to a medium flow mode, the fluidizing device is closed after purging is carried out for 5 seconds, the powder regulating valve is closed, the gas flow of a conical section gas source and the fluidizing device connected with the bottom end of the conical section is adjusted to a high flow mode, the powder in the powder spraying tank is forcibly stirred, and the surface slope of a material pile caused by large-flow powder spraying is eliminated.

8. A powder spraying method as claimed in claim 7, wherein the powder spraying adjustment method comprises:

the powder shut-off valve is closed without normal powder discharge, the powder regulating valve is slowly increased to the maximum opening degree, the gas flow of the fluidizing device connected with the powder regulating valve is increased to the medium flow mode, the low flow mode is returned after purging for 5 seconds, the opening degree of the powder regulating valve is slowly reduced to the secondary powder discharge opening degree, the powder shut-off valve is opened again, and the powder flow is measured to judge whether the powder is normally discharged.

9. A powder spraying method as claimed in claim 7, wherein the difference between the pressure in the powder spraying tank and the pressure in the sprayer is also determined during the powder spraying process;

the powder spraying mechanism discharges powder normally, and in the process of slowly increasing the opening of the powder regulating valve, if the difference value between the pressure in the powder spraying tank and the pressure of the ejector is less than 0.1MPa, the opening of the powder regulating valve is stopped to be increased, and even if the powder spraying flow does not reach a set value, the opening of the powder regulating valve is not increased any more; and if the difference value between the pressure in the powder spraying tank and the pressure of the ejector is less than 0.05MPa, immediately closing the powder cut-off valve.

10. A powder spraying method as claimed in claim 7, wherein the minimum powder outlet opening is 10-30%; the secondary powder outlet opening is 2-5% larger than the minimum powder outlet opening.

Technical Field

The invention relates to the technical field of converter steelmaking, in particular to a powder spraying device, a powder spraying device for converter bottom blowing powder spraying and a powder spraying method.

Background

The converter bottom blowing powder spraying is an advanced steelmaking process for spraying raw and auxiliary materials required by steelmaking into a molten pool from the bottom in a powder form by utilizing carrier gas, and can strengthen the stirring of the molten pool, enlarge a slag-metal reaction interface and improve the thermodynamic and kinetic conditions of converter steelmaking. Compared with a conventional top-bottom combined blown converter for blowing inert gas at the bottom, the converter bottom blowing powder injection has obvious advantages in the aspects of reducing the consumption of steelmaking raw and auxiliary materials, reducing the generation amount of solid wastes, improving the purity of molten steel and the like.

The powder spraying device is one of the core equipment of the converter bottom blowing powder spraying process, and the powder airflow state generated by the powder spraying device is directly related to the working state of the bottom blowing nozzle, so that the service life of the bottom blowing nozzle is influenced. In the process of converter steelmaking, the bottom blowing nozzle is covered by high-temperature molten steel, and the powder gas flow is directly sprayed into the high-temperature molten steel by the bottom blowing nozzle, and the process is characterized by comprising the following steps: (1) in order to avoid the base erosion of the powder airflow generated near the outlet of the bottom blowing nozzle, the powder airflow is required to be sprayed out from the nozzle at a critical sonic speed and sprayed into the molten steel in a jet flow form, so the powder airflow generated by the powder spraying device must be in a high-pressure dilute phase conveying state, and the static pressure of the powder airflow is usually 1.0-1.5 MPa; (2) in order to spray all powder required by steelmaking into a molten pool in a short time, the powder spraying flow is large, the powder spraying flow is usually 100-2000 kg/min, and the phenomenon of center through easily occurs in a powder spraying tank; (3) since the bottom-blowing nozzle is covered by high-temperature molten steel, the stable state of the powder flow must be ensured, and sudden large fluctuation of the powder flow is avoided, especially when powder injection is started and stopped, otherwise molten steel can flow backward and enter the bottom-blowing nozzle, and the bottom-blowing nozzle will lose efficacy immediately.

The existing powder spraying device is generally suitable for a low-pressure concentrated phase conveying working condition, has poor powder airflow stability, cannot adapt to complex working condition conditions, cannot adapt to the working condition of a converter bottom blowing powder spraying process, and has poor powder spraying effect. In the existing powder spraying method, all switches are directly closed at the stages of starting powder spraying and stopping powder spraying, the stability of powder airflow is poor, and the safety and stability of the powder spraying process are difficult to ensure.

Disclosure of Invention

The invention provides a powder spraying device, a powder spraying device for bottom blowing powder spraying of a converter and a powder spraying method.

The existing powder spraying device has the following problems that the existing powder spraying device is generally suitable for a low-pressure concentrated phase conveying working condition, the stability of powder airflow is poor, the existing powder spraying device cannot adapt to complex working condition conditions, cannot adapt to the working condition of a converter bottom blowing powder spraying process, and is poor in powder spraying effect.

The existing powder spraying method has the following problems,

all switches are directly closed at the stages of starting powder spraying and stopping powder spraying, so that the stability of powder airflow is poor, and the safety and stability of the powder spraying process are difficult to ensure; for the abnormal powder discharging condition of the powder spraying device, a safe, stable and effective disposal means is lacked, so that a blanking pipe is easily blocked, or a large amount of powder is discharged instantly.

To solve the above technical problem, an embodiment of the present invention provides the following solutions:

a powder spraying device comprises a powder spraying tank, wherein the powder spraying tank is respectively connected with a pressurized gas source, a powder bin and a dust remover;

the lower part of the powder spraying tank is a conical section, and the conical section is connected with a conical section gas source;

the bottom of the conical section, the fluidizing device, the powder cut-off valve, the fluidizing device, the powder regulating valve and the powder spraying mechanism are sequentially connected.

The powder spraying mechanism comprises a powder flow sprayer connected with the powder regulating valve, and the powder flow sprayer is connected with a powder spraying carrier gas source.

The fluidization device comprises a fluidization section and a fluidization gas source connected with the fluidization section, the fluidization section is connected between the conical section and the powder stop valve, and the fluidization section is connected between the powder stop valve and the powder adjusting valve.

The powder spraying device further comprises a powder spraying tank internal pressure measuring device, and the powder spraying tank internal pressure measuring device is arranged on the powder spraying tank.

Wherein, still be provided with sprayer pressure measurement device on the powder air current sprayer.

The powder spraying device for bottom blowing powder spraying of the converter comprises the powder spraying device, wherein a powder spraying mechanism of the powder spraying device is connected with a distributor through a powder conveying pipeline, a powder flowmeter is arranged on the powder conveying pipeline, and the distributor is connected with a bottom blowing nozzle.

A powder spraying method comprises a powder adding process, a powder spraying process and a powder stopping process;

in the powder adding process, a dust remover, a conical section gas source and a fluidizing device connected with the bottom end of the conical section are opened, the conical section gas source and the gas flow of the fluidizing device are in a low flow mode, other equipment is in a closed state, after the pressure in a powder spraying tank is continuously lower than 0.05MPa for 10 seconds, a powder bin is opened, powder enters the powder spraying tank, when the weight of the powder in the powder spraying tank reaches a preset value, the powder bin and the dust remover are closed, a pressurizing gas source is opened, and the pressure in the powder spraying tank is kept at the preset value;

in the powder spraying process, a powder regulating valve, a fluidizing device connected with the powder regulating valve and a powder cut-off valve are opened in sequence, the powder regulating valve is at the minimum powder outlet opening, and the gas flow of the fluidizing device executes a low flow mode; measuring the flow of powder sprayed by the powder spraying mechanism and judging whether the powder is discharged normally; normally discharging powder, slowly increasing the opening of a powder regulating valve, and keeping the opening of the powder regulating valve unchanged when the flow of the sprayed powder reaches a set value; abnormal powder discharging, executing a powder spraying adjusting method, measuring the flow of powder sprayed by a powder spraying mechanism, judging whether the powder is discharged normally, and repeating the operation;

and in the powder stopping process, after the powder spraying amount reaches the process requirement, the opening degree of a powder regulating valve is slowly reduced to the minimum powder outlet opening degree, then a powder stop valve is closed, the powder regulating valve is slowly increased to the maximum opening degree, the gas flow of a fluidizing device connected with the powder regulating valve is increased to a medium flow mode, the fluidizing device is closed after purging is carried out for 5 seconds, the powder regulating valve is closed, the gas flow of a conical section gas source and the fluidizing device connected with the bottom end of the conical section is adjusted to a high flow mode, the powder in the powder spraying tank is forcibly stirred, and the surface slope of a material pile caused by large-flow powder spraying is eliminated. Stream flow stream

The powder spraying adjusting method comprises the following steps:

the powder shut-off valve is closed without normal powder discharge, the powder regulating valve is slowly increased to the maximum opening degree, the gas flow of the fluidizing device connected with the powder regulating valve is increased to the medium flow mode, the low flow mode is returned after purging for 5 seconds, the opening degree of the powder regulating valve is slowly reduced to the secondary powder discharge opening degree, the powder shut-off valve is opened again, and the powder flow is measured to judge whether the powder is normally discharged.

Wherein, the difference between the pressure in the powder spraying tank and the pressure of the ejector is also required to be judged in the powder spraying process;

the powder spraying mechanism discharges powder normally, and in the process of slowly increasing the opening of the powder regulating valve, if the difference value between the pressure in the powder spraying tank and the pressure of the ejector is less than 0.1MPa, the opening of the powder regulating valve is stopped to be increased, and even if the powder spraying flow does not reach a set value, the opening of the powder regulating valve is not increased any more; and if the difference value between the pressure in the powder spraying tank and the pressure of the ejector is less than 0.05MPa, immediately closing the powder cut-off valve.

Wherein the minimum powder outlet opening is 10-30%;

the secondary powder outlet opening is 2-5% larger than the minimum powder outlet opening.

The scheme of the invention at least comprises the following beneficial effects:

according to the scheme, the powder flow sprayed by the powder spraying device is stable in state, sudden large fluctuation of the powder flow is avoided, the powder spraying effect is good, and the powder spraying device is suitable for complex working conditions and working conditions of a converter bottom blowing powder spraying process.

The powder spraying method provided by the invention has the advantages of good powder airflow stability, safe and stable powder spraying process and good powder spraying effect. (1) The invention starts to spray powder and stops spraying powder with minimum flow, can reduce the fluctuation of powder airflow state when spraying powder and stopping spraying powder to the utmost extent, reduce the impact on the spraying process and avoid the occurrence of the accident of molten steel back flow; (2) the powder spraying method provided by the invention can safely and effectively treat the abnormal powder discharge condition of the powder spraying device, can not cause sudden large powder discharge, and can also avoid the condition that powder is accumulated between the stop valve and the regulating valve to cause the blockage of the blanking pipe; (3) after the powder spraying is finished, the material pile is subjected to high-flow mixing, so that the surface gradient of the material pile caused by high-flow powder spraying can be effectively eliminated, and the central through phenomenon in the next powder spraying process is avoided; (4) in the feeding step of the invention, the powder cut-off valve and the powder regulating valve are both in a closed state, the powder spraying carrier gas can be normally sprayed out by the powder flow sprayer, and the feeding operation of the powder spraying device can be carried out after the powder spraying is finished, thus saving the time.

The powder spraying device for bottom blowing powder spraying of the converter is provided with the powder stop valve and the powder regulating valve, in the feeding step, the powder stop valve and the powder regulating valve are both in a closed state, and powder spraying carrier gas can be normally sprayed into a converter molten pool through the powder flow sprayer, the powder conveying pipeline, the distributor and the bottom blowing nozzle, so that the feeding operation of the powder spraying device can be carried out once powder spraying is finished in the smelting process of the converter, the smelting of the converter and the feeding of the powder spraying device can be synchronously carried out, the time is saved, and the normal smelting rhythm of the converter is prevented from being delayed.

Drawings

FIG. 1 is a first schematic diagram of a powder spraying device according to the present invention;

FIG. 2 is a second schematic diagram of the powder spraying device of the present invention;

fig. 3 is a schematic view of the powder injection device for bottom blowing powder injection of the converter of the present invention.

Flow of

Detailed Description

Exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. While exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be embodied in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art.

As shown in fig. 1, the embodiment provides a powder spraying device, which includes a powder spraying tank, where the powder spraying tank is respectively connected to a pressurized gas source, a powder bin, and a dust remover; the lower part of the powder spraying tank is a conical section, and the conical section is connected with a conical section gas source; the bottom of the conical section, the fluidizing device, the powder cut-off valve, the fluidizing device, the powder regulating valve and the powder spraying mechanism are sequentially connected.

In the use process of the powder spraying device, the powder is firstly added into the powder spraying tank and then sprayed, and the powder spraying is stopped after the powder spraying is finished.

In the feeding process, the powder stop valve and the powder regulating valve are closed, the pressurizing air source is closed, the dust remover is opened, the air source of the conical section and the fluidizing device connected with the bottom end of the conical section are opened, at the moment, the gas flow of the fluidizing device is in a low flow mode, after the pressure in the powder spraying tank lasts for 10 seconds and is lower than 0.05MPa, the powder bin is opened, and the powder enters the powder spraying tank. And when the weight of the powder in the powder spraying tank reaches a preset value, closing the powder bin, closing the dust remover, opening the pressurized air source, inflating the pressurized air source into the powder spraying tank, and keeping the pressure in the powder spraying tank at the preset value.

In the powder spraying process, firstly, opening a powder regulating valve to the minimum powder outlet opening, opening a fluidizing device connected with the powder regulating valve, executing a low flow mode on the gas flow of the fluidizing device, then opening a powder stop valve, measuring the powder flow sprayed by a powder spraying mechanism, judging whether the powder is normally discharged, if the powder is normally discharged by the powder spraying mechanism, slowly increasing the opening of the powder regulating valve so as to increase the powder spraying flow, and keeping the opening of the powder regulating valve unchanged when the powder spraying flow reaches a set value; if the powder spraying mechanism does not normally discharge powder, the powder stop valve is closed, the opening of the powder regulating valve is increased until the powder regulating valve is completely opened, the gas flow of the fluidizing device connected with the powder regulating valve is increased to a medium flow mode, the low flow mode is returned after purging for 5 seconds, then the opening of the powder regulating valve is reduced to a secondary powder discharge opening, the powder stop valve is opened again, the powder flow is measured, whether the powder discharge is normally performed or not is judged, and the operation is repeated.

In the powder stopping process, after the powder spraying amount meets the process requirement, firstly, slowly reducing the opening of a powder regulating valve to the minimum powder outlet opening, then closing a powder stop valve, increasing the opening of the powder regulating valve until the powder regulating valve is fully opened, increasing the gas flow of a fluidizing device connected with the powder regulating valve to a medium flow mode, blowing for 5 seconds, closing the fluidizing device, and closing the powder regulating valve; after the powder stop valve and the powder regulating valve are completely closed, the gas flow of the gas source of the conical section and the gas flow of the fluidizing device connected with the bottom end of the conical section are regulated to be in a high-flow mode, powder in the powder spraying tank is stirred strongly, the surface gradient of a material pile caused by large-flow powder spraying is eliminated, and the phenomenon of center through during next powder spraying is avoided.

The powder spraying device of the embodiment has stable state of the sprayed powder airflow, avoids sudden large fluctuation of the powder airflow, has good powder spraying effect, is suitable for complex working condition conditions, and is suitable for the working condition of the converter bottom blowing powder spraying process.

As shown in fig. 2, the powder spraying mechanism includes a powder gas flow injector connected to the powder regulating valve, and the powder gas flow injector is connected to the powder spraying carrier gas source. The powder air flow ejector is also provided with an ejector pressure measuring device. Specifically, the powder spraying mechanism further comprises a powder conveying pipe connected with external equipment, the powder airflow ejector is connected with the external equipment through a powder conveying pipeline, and a powder flowmeter is arranged on the powder conveying pipeline.

The fluidizing device of this embodiment includes the fluidization section and connects the fluidization air supply of fluidization section, and the fluidization section is connected between toper section and powder trip valve, and the fluidization section is connected between powder trip valve and powder governing valve. The powder spraying tank is connected with a pressurized air source through a pressurized pipe; the powder spraying tank is connected with the powder bin through a powder inlet pipe; the powder spraying tank is connected with a dust remover through an exhaust pipe 1.

The powder spraying device of the embodiment further comprises a powder spraying tank internal pressure measuring device, and the powder spraying tank internal pressure measuring device is arranged on the powder spraying tank.

The wall surface of the conical section of the embodiment is provided with an air hole which is communicated with an air source of the conical section. The inner wall surface of the fluidization section is of a breathable net structure, and the fluidization section is communicated with a fluidization gas source; the upper end of the powder gas flow ejector is connected with the powder regulating valve, the inlet end of the powder gas flow ejector is connected with the powder spraying carrier gas source, and the outlet end of the powder gas flow ejector is connected with the powder conveying pipeline.

The embodiment provides a powder spraying method, which comprises a powder adding process, a powder spraying process and a powder stopping process;

in the powder adding process, a dust remover, a conical section gas source and a fluidizing device connected with the bottom end of the conical section are opened, a low flow mode is executed on the conical section gas source and the gas flow of the fluidizing device, the gas flow of the low flow mode is 1-10 Nm3/h, other equipment is in a closed state, after the pressure in a powder spraying tank is continuously lower than 0.05MPa for 10 seconds, a powder bin is opened, flowing powder enters the powder spraying tank, when the weight of the powder in the powder spraying tank reaches a preset value, the powder bin and the dust remover are closed, a pressurizing gas source is opened, and the pressure in the powder spraying tank is kept at the preset value;

in the powder spraying process, a powder regulating valve, a fluidizing device connected with the powder regulating valve and a powder cut-off valve are sequentially opened, the powder regulating valve is in a minimum powder outlet opening degree, the minimum powder outlet opening degree is 10-0%, and the gas flow of the fluidizing device executes a low flow mode; measuring the flow of powder sprayed by the powder spraying mechanism and judging whether the powder is discharged normally; normally discharging powder, slowly increasing the opening of a powder regulating valve, and keeping the opening of the powder regulating valve unchanged when the flow of the sprayed powder reaches a set value; abnormal powder discharging, executing a powder spraying adjusting method, measuring the flow of powder sprayed by a powder spraying mechanism, judging whether the powder is discharged normally, and repeating the operation; in the powder spraying adjusting method, powder does not normally flow out, the powder cut-off valve is closed, the powder adjusting valve is slowly increased to the maximum opening, the gas flow of the fluidizing device connected with the powder adjusting valve is increased to the medium flow mode, the medium flow mode is 5-50 Nm3/h, the low flow mode is returned after purging is carried out for 5 seconds, the opening of the powder adjusting valve is slowly reduced to the secondary powder outlet opening, the secondary powder outlet opening is larger than the minimum powder outlet opening by 5 percent, the powder cut-off valve is opened again, and the powder flow is measured to judge whether the powder normally flows out.

And in the powder stopping process, after the powder spraying amount meets the process requirement, the opening of a powder regulating valve is slowly reduced to the minimum powder outlet opening, a powder stop valve is closed, the powder regulating valve is slowly opened to the maximum opening, the gas flow of a fluidizing device connected with the powder regulating valve is increased to a medium flow mode, the fluidizing device is closed after purging for 5 seconds, the powder regulating valve is closed, the gas flow of a gas source of a conical section and the gas flow of the fluidizing device connected with the bottom end of the conical section are regulated to a high flow mode, the high flow mode is 50-100 Nm3/h, the powder in the powder spraying tank is forcibly stirred, and the surface slope of a material pile caused by large-flow powder spraying is eliminated.

In the powder spraying process of the embodiment, the difference value between the pressure in the powder spraying tank and the pressure of the ejector needs to be judged; the powder spraying mechanism discharges powder normally, and in the process of slowly increasing the opening of the powder regulating valve, if the difference value between the pressure in the powder spraying tank and the pressure of the ejector is less than 0.1MPa, the opening of the powder regulating valve is stopped to be increased, and even if the powder spraying flow does not reach a set value, the opening of the powder regulating valve is not increased any more; and if the difference value between the pressure in the powder spraying tank and the pressure of the ejector is less than 0.05MPa, immediately closing the powder cut-off valve.

The rate of change of the opening of the slow adjustment powder damper of this example was less than%/second.

The powder spraying method provided by the invention has the advantages of good powder airflow stability, safe and stable powder spraying process and good powder spraying effect. (1) The invention starts to spray powder and stops spraying powder with minimum flow, can reduce the fluctuation of powder airflow state when spraying powder and stopping spraying powder to the utmost extent, reduce the impact on the spraying process and avoid the occurrence of the accident of molten steel back flow; (2) the powder spraying method provided by the invention can safely and effectively treat the abnormal powder discharge condition of the powder spraying device, can not cause sudden large powder discharge, and can also avoid the condition that powder is accumulated between the stop valve and the regulating valve to cause the blockage of the blanking pipe; (3) after the powder spraying is finished, the material pile is subjected to high-flow mixing, so that the surface gradient of the material pile caused by high-flow powder spraying can be effectively eliminated, and the central through phenomenon in the next powder spraying process is avoided; (4) in the feeding step of the present invention, the powder cut-off valve and the powder regulating valve are both in a closed state, and the powder-spraying carrier gas can be normally sprayed out via the powder flow sprayer.

As shown in fig. 3, the embodiment provides a powder spraying device for bottom blowing powder spraying of a converter, which includes a powder spraying device, a powder spraying mechanism of the powder spraying device is connected with a distributor through a powder conveying pipeline, a powder flowmeter is arranged on the powder conveying pipeline, and the distributor is connected with a bottom blowing nozzle. Specifically, the powder spraying mechanism comprises a powder gas flow sprayer connected with a powder cut-off valve, the powder gas flow sprayer is connected with a powder spraying carrier gas source, and the powder gas flow sprayer is connected with a distributor through a powder conveying pipeline. In this embodiment, the fluidizing device connected to the bottom end of the conical section includes a first-stage fluidizing section and a first-stage fluidizing gas source, and the fluidizing device connected to the powder regulating valve includes a second-stage fluidizing section and a second-stage fluidizing gas source.

The powder spraying method of the powder spraying device for the bottom blowing powder spraying of the converter in the embodiment comprises the following steps:

(1) the charging step of the powder spraying device is carried out at the non-smelting stage of the converter: closing the powder stop valve and the powder regulating valve, closing the pressure increasing pipe, opening the exhaust pipe, and opening the conical section gas source and the primary fluidized gas source, wherein the gas flow of the conical section gas source and the primary fluidized gas source are both in a low flow mode, and after the pressure in the powder spraying tank is continuously lower than 0.05MPa for 10 seconds, the powder inlet pipe is opened, and the powder in the powder bin is conveyed into the powder spraying tank; and when the weight of the powder in the powder spraying tank reaches a preset value a tons, closing the powder inlet pipe, closing the exhaust pipe, opening the pressurization pipe 8, inflating the powder spraying tank by a pressurization gas source, and keeping the pressure in the powder spraying tank at a preset value bMPa.

(2) After the converter starts smelting, performing powder spraying according to the smelting process: firstly, opening a powder regulating valve to a minimum powder outlet opening degree of c%, opening a secondary fluidization gas source, executing a low flow mode d Nm3/h on the gas flow of the secondary fluidization gas source, then opening a powder cut-off valve, and judging whether the powder spraying device normally discharges powder or not according to the measurement result of a powder flowmeter; if the powder spraying device discharges powder normally, the opening of the powder regulating valve is slowly increased, the change rate of the opening of the powder regulating valve is 2%/second, so that the powder spraying flow is increased, and when the powder spraying flow reaches a set value e kg/min, the opening of the powder regulating valve is kept unchanged; if the powder spraying device does not normally discharge powder, closing the powder stop valve, slowly increasing the opening of the powder regulating valve until the powder regulating valve is completely opened, increasing the gas flow of the secondary fluidized gas source to fNm3/h in the medium flow mode, purging for 5 seconds, returning to the low flow mode, then reducing the opening of the powder regulating valve to g% of the secondary powder discharge opening, opening the powder stop valve again, judging whether the powder spraying device normally discharges powder again according to the measurement result of the powder flowmeter, and repeating the operations.

(3) Powder stopping step: after the powder spraying amount reaches hkg of the process requirement, firstly, slowly reducing the opening of a powder regulating valve to the minimum powder outlet opening i%, wherein the change rate of the opening of the powder regulating valve is%/second, then closing a powder stop valve, slowly increasing the opening of the powder regulating valve until the powder regulating valve is fully opened, increasing the gas flow of a secondary fluidized gas source to a medium flow mode g Nm3/h, blowing for 5 seconds, closing the secondary fluidized gas source, and closing the powder regulating valve; after the powder stop valve and the powder regulating valve are completely closed, the gas flow of the conical section gas source and the primary fluidized gas source is regulated to be in a high-flow mode k Nm3/h, powder in the powder spraying tank is forcibly stirred, the surface gradient of a material pile caused by large-flow powder spraying is eliminated, and the phenomenon of center through during next powder spraying is avoided.

(4) If the powder allowance in the powder spraying tank is lower than 1 ton after the powder spraying of a certain furnace is finished, the charging step of the invention is started immediately after the powder spraying of the furnace is finished, and the converter smelting is not required to be finished.

In the powder spraying step, if the powder spraying device discharges powder normally, the opening of the powder regulating valve is increased slowly, and in the process of increasing the opening of the powder regulating valve slowly, if the difference value between the pressure in the powder spraying tank and the pressure of the ejector is less than 0.1MPa, the increase of the opening of the powder regulating valve is stopped, and even if the powder spraying flow rate does not reach a set value, the opening of the powder regulating valve is not increased any more; and if the difference between the pressure in the powder spraying tank and the pressure of the ejector is less than 0.05MPa, immediately closing the powder cut-off valve.

Specifically, the powder spraying device for bottom blowing powder spraying of the converter of the embodiment can be applied to converters of 120 tons and 300 tons, and the parameter setting table 1 is shown. When the method is applied to a 120-ton converter, two bottom blowing nozzles are arranged at the bottom of the converter and used for blowing lime powder, the maximum powder spraying flow of the two bottom blowing nozzles is 150kg/min, the powder airflow backpressure is about 1.2MPa, and about 900kg of powder is sprayed into the converter through the two bottom blowing nozzles every time according to the process requirement. When the powder spraying device is applied to a 00-ton converter, four bottom blowing nozzles are arranged at the bottom of the converter and used for spraying lime powder, the maximum powder spraying flow of the four bottom blowing nozzles is 600kg/min, the powder airflow backpressure is about 1.3MPa, and about 000kg of powder is sprayed into the converter through the four bottom blowing nozzles at each time according to the process requirement.

TABLE 1 parameter setting table

The implementation result shows that: the powder spraying device for bottom blowing powder spraying of the converter is applied to the converters of 120 tons and 300 tons, the stability of the powder spraying process is greatly improved, the accident of molten steel backflow caused by sudden increase of powder quantity does not occur, and the situation that the blanking pipe is blocked by powder does not occur. When the powder spraying tank is applied for 120 tons, the phenomenon that the center of a material pile in the tank is communicated in the powder spraying process is avoided under the condition that the residual quantity of powder in the powder spraying tank is higher than 1 ton, the bottom blowing nozzle is uniformly eroded, and the average erosion rate is reduced by 20 percent. When 300 tons of powder are applied, the phenomenon that the center of a material pile in the powder spraying tank is communicated in the powder spraying process is avoided under the condition that the residual quantity of powder in the powder spraying tank is higher than 2 tons, the bottom blowing nozzle is uniformly eroded, and the average erosion rate is reduced by 15%.

In the powder spraying process of the powder spraying device for bottom blowing powder spraying of the converter, in the feeding step, the powder stop valve and the powder regulating valve are both in a closed state, and the powder spraying carrier gas can be normally sprayed into a converter molten pool through the powder flow sprayer, the powder conveying pipeline, the distributor and the bottom blowing nozzle, so that the feeding operation of the powder spraying device can be carried out once the powder spraying is finished in the converter smelting process, the converter smelting and the powder spraying device can be synchronously carried out, the time is saved, and the delay of the normal smelting rhythm of the converter is avoided.

While the foregoing is directed to the preferred embodiment of the present invention, it will be understood by those skilled in the art that various changes and modifications may be made without departing from the spirit and scope of the invention as defined in the appended claims.