JP2003171677A - Dust coal fuel producing apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To remove a ground coal deposited on a screen to prevent clogging while a classifier is operated. <P>SOLUTION: The dust coal fuel producing apparatus comprising a multistage classifier 1 having a plurality of screens 2 for classifying a coarse ground coal is provided with a fluid spraying means 8a for spraying a fluid on at least a lowermost screen 3 of the multistage classifier. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a pulverized coal fuel production apparatus.

[0002]

2. Description of the Related Art Conventionally, a pressurized fluidized bed combustion furnace has an air supply means for supplying air for fluidizing particles to burn fuel, a fuel supply means for supplying fuel, and a pulverized coal for producing fuel for supply. It is known to have a fuel production device. Further, the pulverized coal fuel production apparatus is provided with a multistage classifier for classifying the pulverized coal based on particle characteristics, for example, particle size.

This multi-stage classifier is provided with a plurality of screens provided inside for classifying crushed coal, a charging port for charging crushed coal from the upper part, a screen residual outlet for discharging screen residue from the body, and a bottom part. It is provided with a pulverized coal outlet for discharging classified pulverized coal, that is, pulverized coal. In addition, the screen is a sieve with a fixed mesh size.

In the multi-stage classifier thus constructed, crushed carbon is screened, for example, 50 mm, 20 mm, 6 mm.
The pulverized coal is separated by classifying the particle size in multiple stages. Then, the separated pulverized coal, paste fuel obtained by kneading water and a desulfurizing agent (hereinafter, referred to as Coal-Water P
istes; described as CWP) is used as a fuel for a pressurized fluidized bed combustion furnace.

[0005]

By the way, when classifying crushed carbon containing water, there is a possibility that the crushed carbon adheres to the screen arranged at the lowermost stage to cause clogging.
Therefore, the multistage classifier is normally vibrated with a certain amplitude to prevent the screen from being clogged. In addition, it is necessary to regularly stop the multi-stage classifier for cleaning. When the frequency of cleaning increases, the amount of pulverized coal produced decreases and CWP becomes insufficient.

Therefore, focusing on the fact that crushed carbon containing water on the surface tends to adhere to the screen, a method of drying the surface of the crushed carbon in advance using warm air or a kiln has been considered. However, even if the pulverized coal is dried, it is necessary to mix water again when the CWP is produced, which causes a problem that the amount of heat for drying is wasted.

An object of the present invention is to prevent the screen from being clogged while the classifier is in operation.

[0008]

The present invention provides a pulverized coal fuel production apparatus equipped with a multi-stage classifier having a plurality of screens for classifying coarsely pulverized coal, wherein at least the bottom screen of the multi-stage classifier is fluidized. It is characterized in that a fluid spraying means for spraying is provided.

As described above, by spraying the fluid, the crushed carbon adhering to the screen can be removed and clogging of the screen can be prevented. The fluid spraying means according to the present invention can be carried out while the multi-stage classifier is operating, and further, C
This is convenient because the production efficiency of WP can be increased.

In this case, the fluid sprayed on the screen may be any one of air, air and water, air and water and a dispersant, and steam. Even if water is mixed, there is no problem because it can be used as water for the subsequent CWP production.

Further, so that the fluid can be sprayed appropriately,
It is preferable to intermittently spray the fluid onto the screen.

Further, by attaching a nozzle to a support pipe supporting the screen and spraying the fluid from the nozzle, the flow of the pulverized coal in the classification process is not hindered,
A fluid can be sprayed.

Further, in order to prevent scattering of the crushed coal and diffusion of the sprayed fluid, it is preferable to install a closing plate for closing the outlet of the screen residue.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic view showing a vertical cross section of an embodiment of a multi-stage classifier to which the present invention is applied.

As shown in FIG. 1, the multi-stage classifier 1 has a screen 2 for classifying crushed coal, a screen 3 for further classifying the crushed coal classified by the screen 2, and a charging port for charging the crushed coal from above. 4, a screen residual outlet 5 for discharging the screen residual of the screen 2, a screen residual outlet 6 for discharging the screen residual of the screen 3, and a pulverized coal outlet 7 for discharging the separated pulverized coal. The fluid spraying means 8a to 8c are arranged at positions where the fluid can be sprayed onto the screen 3.

[0016] The crushed coal charged in the multistage classifier 1 is
The screen 2 classifies coarsely crushed coal and finely crushed coal. The coarsely crushed coal is discharged out of the system through the screen residual outlet 5. Then, the finely pulverized coal is further classified by the screen 3. In the screen 3, crushed carbon having a particle size of 6 mm or more, for example, 6
It is divided into pulverized coal having a size of not more than mm, that is, fine coal. For example, crushed carbon of 6 mm or more is discharged from the screen residual outlet 6 and crushed again by a crusher (not shown). On the other hand, pulverized coal is used as fuel.

In many cases, the screen 3 of such a multi-stage classifier 1 is often covered with crushed coal and causes clogging.
Therefore, the fluid is sprayed from the fluid spraying means 8a to 8c according to the present invention to the screen 3 to remove the crushed coal.

FIG. 2 is a schematic view showing a horizontal section of the multistage classifier of FIG. As shown in FIG. 2, fluid spraying means 8a to 8o and pipes 10a to 10c for connecting the fluid spraying means 8a to 8o to a fluid supply means (not shown).
And valves 11a to 11c provided on the pipes 10a to 10c, respectively.
11c and.

By opening and closing the valves 11a to 11c, the fluid is sprayed intermittently from the fluid spraying means 8a to 8o onto the screen 3 to remove the crushed carbon adhering to the screen 3.

FIG. 3 is a schematic view showing a horizontal cross section of another multi-stage classifier to which the present invention is applied. As shown in the drawing, the fluid spraying means 8a to 8o and the fluid spraying means 8a.
A pipe 10 for connecting 8o to an air supply means (not shown)
a to 10c, valves 11a to 11c provided on the pipes 10a to 10c, and fluid spraying means 8a to 8c.
Pipes 26a to 2 for connecting o to a water supply means (not shown)
6c and a valve 24 provided on the pipes 26a to 26c
a to 24c.

Valves 11a-11c and valves 24a-2
By simultaneously opening and closing 4c, the air supplied from the air supply means and the water supplied from the water supply means are sprayed onto the screen 3 from the fluid spraying means 8a to 8o to remove the adhered coal.

FIG. 4 is a schematic view showing another embodiment of the multistage classifier of FIG. As shown in FIG. 4, in addition to the configuration shown in FIG. 3, a dispersant pipe 28 for connecting the water pipe 27 to a dispersant supply means (not shown) is provided.

The dispersant supplied from the dispersant supply means (not shown) is injected into the water in the water pipe 27. By spraying the injected water onto the screen 3 from the fluid spraying means 8a to 8o, it is possible to remove the crushed carbon adhering to the screen 3.

FIG. 5 is a schematic view showing a horizontal section of another embodiment to which the present invention is applied. As shown in FIG. 5, the fluid spraying means 8a to 8o and the fluid spraying means 8a.
A pipe 10 for connecting 8o to a steam supply means (not shown)
a to 10c and valves 11a to 11c provided on the pipes 10a to 10c.

By opening and closing the valves 11a to 11c,
Fluid spraying means 8a to 8o from the steam supply means
To the screen 3 intermittently to remove the attached crushed carbon.

FIG. 6 is a schematic view showing a vertical sectional view of another embodiment to which the present invention is applied. As shown in FIG. 6, the multi-stage classifier 1 includes a screen 2 for classifying crushed coal, a screen 3 for further classifying finely crushed coal classified by the screen 2, and a charging port 4 for charging crushed coal from above. , Screen residual outlet 5 for discharging the screen residual of screen 2
And a screen residue outlet 6 for discharging the screen residue of the screen 3, and a pulverized coal outlet 7 for discharging the classified pulverized coal.
It has and. The support tubes 30a to 30c supporting the screen 2 are used as fluid spraying means, and fluid spraying nozzles 31a to 31c are used.

A fluid supplied from a fluid supply means (not shown) is sprayed from the fluid spray nozzles 31a to 31c onto the screen 3 to remove the adhering crushed carbon.

FIG. 7 is a schematic view showing a vertical sectional view of another embodiment to which the present invention is applied. As shown in FIG. 7, the multi-stage classifier 1 includes a screen 2 for classifying crushed coal, a screen 3 for further classifying finely crushed coal classified by the screen 2, and a charging port 4 for charging crushed coal from above. , Screen residual outlet 5 for discharging the screen residual of screen 2
And a screen residue outlet 6 for discharging the screen residue of the screen 3, and a pulverized coal outlet 7 for discharging the classified pulverized coal.
And fluid spraying means 8a to 8c. Further, closing screens 40a and 40b are provided at the screen residual outlets 5 and 6, respectively.

The fluid supplied from the fluid supply means (not shown) is supplied to the screen 3 from the fluid spraying means 8a to 8c.
To remove the crushed charcoal attached. At this time,
The closing plates 40a and 40b are closed mechanically or by the pressure of the fluid so that the sprayed fluid does not diffuse to the screen residual outlets 5 and 6.

By adjusting the diameters of the injection ports of the fluid spraying means 8a to 8o described with reference to FIGS.
A fluid can be sprayed on the entire screen to be sprayed.

[0031]

As described above, according to the present invention, it is possible to prevent the screen from being clogged while the classifier is operating.

[Brief description of drawings]

FIG. 1 is a schematic view showing a vertical cross section of an embodiment of a multi-stage classifier to which the present invention is applied.

FIG. 2 is a schematic diagram showing a horizontal cross section of the multi-stage classifier of FIG.

FIG. 3 is a schematic view showing a horizontal cross section of another multi-stage classifier to which the present invention is applied.

FIG. 4 is a schematic view showing another embodiment of the multi-stage classifier of FIG.

FIG. 5 is a schematic view showing a horizontal cross section of another multi-stage classifier to which the present invention is applied.

FIG. 6 is a schematic view showing a vertical sectional view of another multistage classifier to which the present invention is applied.

FIG. 7 is a schematic view showing a vertical sectional view of another multi-stage classifier to which the invention is applied.

[Explanation of symbols]

1 Multi-stage classifier 3 screen 8a Fluid spraying means

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Toshio Murakami             Babcock Hitachi 6-9 Takaracho, Kure City, Hiroshima Prefecture             Kure Office Co., Ltd. (72) Inventor Takehiro Hiroshi             Babcock Hitachi 3-36 Takaracho, Kure City, Hiroshima Prefecture             Kure Institute Co., Ltd. F term (reference) 4D021 AA03 AB02 CA01 DA01 DA13                       DA20 DB16 EA10 EB01                 4H013 AA01 DB15

Claims (5)

[Claims] 1. A pulverized coal fuel production apparatus equipped with a multi-stage classifier having a plurality of screens for classifying coarsely pulverized coal, wherein fluid spraying means for spraying a fluid is provided on at least the bottom screen of the multi-stage classifier. A pulverized coal fuel production apparatus characterized by the above. 2. The pulverized coal fuel production apparatus according to claim 1, wherein the fluid spraying means intermittently sprays the fluid onto the screen. 3. The pulverized coal fuel production apparatus according to claim 1, wherein the fluid is one of air, air and water, air and water and a dispersant, and steam. 4. The pulverized coal fuel production apparatus according to claim 1, wherein a nozzle is attached to a support pipe supporting the screen, and the fluid is sprayed from the nozzle. 5. The pulverized coal fuel production apparatus according to claim 1, further comprising a closing plate that closes the outlet of the screen residue.