JPH0733530B2 - Powder injection method - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to continuous feeding of powder such as cement (indicating powder, granules or a mixture thereof), including feeding and blowing of pulverized coal or fine ore into a blast furnace.
It concerns the blowing method.

[0002]

2. Description of the Related Art For example, taking pulverized coal blowing in a blast furnace as an example, in the example shown in FIG. 4, the blasting hoppers 2 and 2'arranged in parallel are provided, and the pulverized coal is cut out by a load cell. The weight signal from 15, 15 'is sent to the pressure control valve 18, 18'.
And is controlled by increasing or decreasing the pressure in the blow hoppers 2, 2 '.

In this example, in order to suppress the variation of the cutting amount when the blow hoppers 2, 2'are switched, the inside of the high concentration pipe 20 having a high solid gas concentration and connected to the lower portions of the blow hoppers 2, 2 '. It is necessary to balance the resistance of No. 1 with the pressure in the blow hoppers 2, 2'and the blowing pressure of the blast furnace, but this is not easy.

Further, since the inside of the pipe 20 has a high solid gas concentration, a very high pressure loss occurs up to the mixing portion with the carrier gas. Therefore, the blow hoppers 2, 2'need to have a high pressure supply structure. Become. In addition, since fluidization and agitation are not performed in the lower part of the blow hoppers 2, 2 ', powder compaction occurs, cutting is not smooth, there is a problem of particle size segregation, etc. There is a problem that it is difficult to stably and continuously cut out and convey the mixture with air.
In particular, there is a problem of variation in the blowing amount when switching the blowing hoppers 2, 2 '.

On the other hand, in the example of FIG. 5, the storage hopper 1, the intermediate hopper 22, and the blow hopper 2 are arranged in series, and the blow amount is set by the weight signal from the load cell 15 below the blow hopper 2. Revolving powder feeder 21
The cut-out amount is controlled by transmitting it to and increasing / decreasing its rotation speed.

[0006] In this example, since there is only one blowing hopper, it is not necessary to consider the variation in the amount of cutting at the time of switching, but during the time when the pulverized coal is charged from the intermediate hopper 22 to the blowing hopper 2, cutting and filling are performed. Since it is difficult to grasp the true amount of cutting, and there is a concern that the pulverized coal will be compacted in the lower part of the blowing hopper 2, the cutting is not always smooth and a uniform pulverized coal is obtained. There is a problem that it is difficult to stably and continuously cut out and convey the mixture with the conveying air.

Since a mechanical cutting mechanism is used for the powder cutting portion, the pressure loss to the mixing portion with the carrier air is smaller than that in the example of FIG. 4 having the high concentration pipe, and the blowing hopper is used. 2 does not require a high pressure supply structure, but since it has the intermediate hopper 22, it has a problem that a station frame for supporting and supporting each equipment is large and construction cost is high (Japanese Patent Laid-Open No. 61-266507). , JP-A-61
No. 153214).

[0008]

SUMMARY OF THE INVENTION According to the present invention, the fluidization and agitation of the powder in the lower part of the powder blowing hopper are promoted to facilitate the cutting, and the mixing of the powder and the carrier gas is made uniform. Provided is a low-cost powder blowing method capable of continuously carrying and blowing while suppressing the variation in the cut-out amount of the mixture. In particular, the present invention provides a powder blowing method in which a plurality of powder blowing hoppers are used and smoothly switched, and the powder can be continuously conveyed and blown at a stable blowing amount for a long time.

[0009]

DISCLOSURE OF THE INVENTION The gist of the present invention is to arrange a plurality of powder blowing hoppers in parallel below a powder storage hopper, and to transfer powder from the powder storage hopper to the plurality of powder blowing hoppers. Alternately, and cut into a powder conveying pipe through a powder supply device equipped with a stirring function installed in the lower part,
In the powder blowing method in which the powder is mixed with the carrier gas and blown, the powder weight and the pressure in the powder blow hopper are measured together with the start of the powder cutting from the powder blow hopper after the powder filling. The powder is characterized by adjusting the pressure according to changes in the powder, adjusting the stirring force of the powder supply device to fluidize the powder, and cutting and blowing the powder into the carrier pipe while suppressing fluctuations in the cutting amount. It is a method of blowing the body. In addition, at this time, in accordance with the start of the cutting of the powder from the powder blowing hopper, the filling of the powder storage hopper into the powder unfilled powder blowing hopper is started, and the weight of the powder in the powder blowing hopper is started. Is measured, the filling is completed when it reaches a predetermined value, the pressure is maintained at a predetermined value before the cutting from the powder blowing hopper during powder cutting is completed, and the stirring force is applied by the powder feeding device. Then, the powder is kept in a fluidized state, and the cutting is started at the end of the cutting from the powder blowing hopper, so that the plurality of powder blowing hoppers are switched and the powder is continuously transferred to the conveying pipe. It is a powder blowing method characterized by cutting and blowing.

[0010]

OPERATION / EXAMPLES The present invention will be described below based on the embodiments shown in FIG.

This embodiment is applied to the injection of pulverized coal into a blast furnace, and two powder injection hoppers 2 and 2'arranged in parallel below the powder storage hopper 1 are switched to change the blast furnace. The pulverized coal is continuously and stably blown into it.

The two powder blowing hoppers 2 and 2'arranged in parallel below the storage hopper 1 for the pulverized coal C are filling pipes provided with filling valves 3A, 3A 'and filling valves 3B, 3B', respectively. It is connected to the lower part of the powder storage hopper 1 by 3, 3 '. Below the powder blowing hoppers 2, 2 ', rotary powder feeding devices 4, 4'having a stirring blade are provided. There is a cutout port in the lower part of the powder supply device 4, 4 ', and these cutout ports are cutout valves 5A, 5A', cutout valves 5B, 5
It is connected to the powder conveying pipe 6 to the blast furnace by cutting pipes 5 and 5'provided with B '.

The powder blowing hoppers 2 and 2'are provided with pressurized gas blowing pipes 7 and 7'for adjusting the pressure in the blowing hoppers 2 and 2 ', and the pressure gauges P and P are provided. The pressurized gas blowing control valves 8 and 8'are controlled according to the pressure values in the blowing hoppers 2 and 2'by means of the pressurized gas blowing pipes 7 and 7 '.
The flow rate of the pressurized gas blown from is controlled to maintain the pressure in the powder blowing hoppers 2, 2'at a predetermined value.

In the upper part of the stirring blades in the powder feeders 4 and 4 ', a fluidizing gas blower having a plurality of gas outlets for fluidizing the pulverized coal in the powder feeders 4 and 4'. Tubes 9 and 9'are attached, from which pressurized gas is blown into the powder feeders 4 and 4 ', where the pulverized coal is maintained in a fluidized state. Reference numerals 10 and 10 'are fluidizing gas injection control valves.

Further, conveyance assisting gas blowing pipes 11 and 11 'are attached near the cutouts of the powder supply devices 4 and 4', and a pressurized gas is blown when the pulverized coal is cut out from the cutouts. Assists in the cutting and transportation of pulverized coal. 12, 1
2'is a transfer auxiliary gas on-off valve.

The upper part of each powder blowing hopper 2, 2'is connected to the upper part of the powder storage hopper 1 by a pressure exhaust pipe 14, 14 'equipped with a pressure relief valve 13, 13', and the powder blowing hopper 2,
The pressure in 2'and the pressure in the powder storage hopper 1 can be adjusted.

The weight measurement values at the load cells 15, 15 'for measuring the weight of the pulverized coal in the powder blowing hoppers 2, 2'are transmitted to the supply control devices 16, 16', and the supply control device 16, 16 'controls the driving of the driving devices M, M', controls the rotation of the stirring blades, measures the momentarily changing weight in the powder blowing hoppers 2, 2 ', and inputs it to the switching control device 17 for calculation. When the measured value reaches a predetermined value after processing, the opening / closing of various valves is controlled via the supply controller 17 to switch between the powder blowing hoppers 2 and 2 '.

Each of the powder blowing hoppers repeats the discharge pressure, filling, pressurization, standby, and blowing (cutting) operations as shown in FIG. 1 powder blowing hopper 2 and N
o. 2 The powder blast hoppers 2'are alternately operated. As a result, the pulverized coal is restrained from changing the amount of cutting even at the time of switching, and is quantified and continuously cut into the powder conveying pipe 6 and mixed with the carrier gas. In this state, it is continuously blown into the blast furnace through the distributor or directly from the tuyere of the blast furnace in a constant amount for a long time. That is, as shown in FIG. No. 1 during blowing (cutting) from the powder blowing hopper 2. 2 In the powder blowing hopper 2 ′, the exhaust pressure valve 13 ′ is opened, the filling valve 3A ′ and the filling valve 3B ′ are opened, and the pulverized coal C from the powder storage hopper 1 is brought to a constant level based on the weight measurement by the load cell 15 ′. Fill until complete.

At this time, the pressurized gas injection adjusting valve 8 ', the fluidizing gas injection adjusting valve 10', and the transfer auxiliary gas on-off valve 12 'are closed. Then, the exhaust pressure valve 13 'is closed and the pressurized gas is blown from the pressurized gas blowing pipe 7', and the pressure is maintained at the set value based on the pressure measurement by the pressure gauge P'and kept in the standby state. At this time, No2. The cut-out valve 5A 'and the cut-out valve 5B' of the powder blowing hopper 2'are closed, the fluidizing gas adjusting valve 10 'of the fluidizing gas blowing pipe 9', and the feeding assistance of the feeding assistance gas blowing pipe 11 '. The gas regulating valve 12 'is closed.

No. being blown 1 Inside the powder blowing hopper 2, the pressurized gas blowing adjusting valve 8 is adjusted to maintain a constant pressure, and while the rotation of the rotary powder feeding device 4 is controlled according to the weight of the pulverized coal by the load cell 15, Cut out to the carrier pipe 6. At this time, the cutoff valves 5A and 5B are open.

No. No. 1 when the weight of the pulverized coal in the powder blowing hopper 2 decreased and reached the switching set value. 2 Switching to blowing (cutting) from the powder blowing hopper 2'is performed.

This switching is performed as shown in FIG.
In response to a weight signal from the load cell 15 of the powder blowing hopper 2, the rotating speed of the stirring blade of the rotary powder feeding device 4 is lowered at a constant gradient, and at the same time, the waiting No. 2 By opening the cut-off valve 5A 'of the powder blowing hopper 2'and opening the cut-off valve 5B' after a fixed time, the rotational speed of the rotary powder feeder 4'is increased at a constant gradient, Minimize the variation in the cutting amount due to switching.

No. 1 When the rotational speed of the rotary powder feeder 4 of the powder blowing hopper 2 reaches the minimum value, the cutoff valve 5A
Is closed, and the cut-out valve 5B is closed after a fixed time, the rotary powder supply device 4 is stopped, and the pressurized gas injection adjusting valve 8,
The fluidizing gas injection adjusting valve 10 and the transfer auxiliary gas on-off valve 12 are closed, and the exhaust pressure for filling the pulverized coal is transferred.

On the other hand, No. 2 When the number of rotations of the rotary powder feeder 4'of the powder blowing hopper 2'has reached a predetermined value, the cut-out valve 5A 'is opened, and after a certain period of time, the cut-out valve 5B' is opened to start cutting. To do.

As described above, the plurality of powder blowing hoppers 2 and 2'arranged in parallel are alternately switched to suppress the fluctuation of the amount of pulverized coal cut into the carrier pipe 6 to stabilize the blast furnace. The pulverized coal could be blown in stably for a long time, and the blast furnace operation could be stabilized. In the case of the normal level pulverized coal cutting amount (blowing amount), the fluctuation range a of the cutting amount was about 20% smaller than that in the case of the pulverized coal blowing by the conventional method.

In addition, the blowing of the fluidizing gas and the carrier auxiliary gas in the rotary powder feeders 4 and 4'of the powder blowing hoppers 2 and 2'rotates the rotary powder feeders 4 and 4 '. However, in order to suppress the consolidation due to the filling of the powder blowing hoppers 2, 2 ′ with the pulverized coal, it is considered that the filling and the waiting are also performed.

The required operations for discharging, filling, pressurizing, waiting, blowing and switching are conditions preset by the supply control device and the switching control device based on measurement signals from the load cell and pressure gauge. Is automatically controlled in accordance with the above, and these setting conditions are appropriately set depending on the application target.

The present embodiment is applied to the injection of pulverized coal into the blast furnace, but the present invention is not limited to this.
It is effective when applied to the case where the powder is continuously and stably blown for a long time, and is effective for blowing powder such as pulverized coal (including coke powder), various ore powder, and cement. Can also be applied.

Further, in this embodiment, the powder storage hopper 1 is used.
The number of powder blowing hoppers is two, but the number of powder blowing hoppers is not limited to this, and the number of powder blowing hoppers, the number of powder blowing hoppers, the number of continuous blowing, and the like
Determine capacity etc.

[0030]

EFFECTS OF THE INVENTION According to the present invention, the cutting of powder can be facilitated, and the amount of cutting can be stabilized by homogenizing the mixing of air flow and pulverized coal, and switching between a plurality of powder blowing hoppers can be performed. It is possible to reduce the variation in the cutout amount due to the above and supply the powder in a fixed amount and continuously.

[Brief description of drawings]

FIG. 1 is a side view illustrating an embodiment of the present invention.

FIG. 2 is an explanatory diagram of an operating state of two powder blowing hoppers.

FIG. 3 is an explanatory diagram of a state in which two powder blowing hoppers are cut out from the rotary powder feeding device.

FIG. 4 is an explanatory side view showing a conventional powder supply device.

FIG. 5 is a side view showing a conventional powder supply device.

[Explanation of symbols]

 1 powder storage hopper 2, 2'powder blowing hopper 3, 3'filling pipe 3A, 3A 'filling valve 3B, 3B' filling valve 4, 4'rotary powder feeding device 5, 5'cutout pipe 5A, 5A 'Cutoff valve 5B, 5B' Cutout valve 6 Powder transfer pipe 7, 7'Pressurized gas injection pipe 8, 8'Pressurized gas injection control valve 9, 9 'Fluidizing gas injection pipe 10, 10' Flow Controlled gas injection valve 11, 11 'Transfer auxiliary gas injection pipe 12, 12' Transfer auxiliary gas on-off valve 13, 13 'Exhaust pressure valve 14, 14' Exhaust pressure pipe 15, 15 'Load cell 16, 16' Supply controller 17 Switching control Device 18, 18 'Pressure control valve 19, 19' Control device 20 High concentration pipe 21 Rotary powder feeder 22 Intermediate tank

Claims (2)

[Claims] 1. A plurality of powder blowing hoppers are arranged in parallel below a powder storage hopper, and powder is alternately charged into the plurality of powder blowing hoppers from the powder storage hopper and installed at a lower portion thereof. In the powder blowing method in which the powder is fed into the powder feeding pipe through the powder feeding device equipped with the agitating function, mixed with the feeding gas, and fed and blown, the powder is fed from the powder feeding hopper after the powder filling. The powder weight and pressure in the powder blowing hopper are measured at the same time as the start of the process, and the pressure is adjusted according to the change in the weight, and the stirring force of the powder supply device is adjusted to fluidize the powder and cut it. A method for injecting powder, characterized by cutting and injecting into a conveying pipe while suppressing fluctuations in the amount of ejection. 2. The powder weight in the powder blowing hopper is started when the powder storing hopper starts filling the powder unfilled powder blowing hopper with the start of the cutting of the powder from the powder blowing hopper. Is measured, the filling is completed when it reaches a predetermined value, the pressure is maintained at a predetermined value before the cutting from the powder blowing hopper during powder cutting is completed, and the stirring force is applied by the powder feeding device. Then, the powder is kept in a fluidized state, and the cutting is started at the end of the cutting from the powder blowing hopper, so that the plurality of powder blowing hoppers are switched and the powder is continuously transferred to the conveying pipe. The powder blowing method according to claim 1, wherein the powder is blown out by cutting.