JPH0433498B2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to a nozzle device for classifying pulverized material in a vertical pulverizer, and for example, in a coal pulverizer for a coal-fired power plant or the like. This relates to a vertical pulverizer equipped with a nozzle device having a suitable structure for ejecting a gas into the pulverized coal bed that has been pulverized in the pulverizer to transport the pulverized coal. It is.

[Background of the invention]

Fig. 4a is a cross-sectional view showing the schematic structure of a conventional vertical ball type coal crusher, Fig. 4b is an enlarged view of section B in Fig. 4a, and Fig. 4c is Fig. 4 B of a
FIG.

In FIGS. 4a, b, and c, inside the coal crusher M, a plurality of crushing balls 2 are connected to an upper ring 15 fixed to the main body of the coal crusher M and a lower ring fixed to the rotating disk 8. It is held in contact with 14. The rotating disk 8 and the lower ring 14 are connected to the center axis Y of the coal crusher M by an electric motor (not shown).
It is rotated in the direction shown by arrow A with −Y as the axis.
As the lower ring 14 rotates in the direction indicated by the arrow A, the plurality of crushing balls 2 rotate between the upper ring 15 and the lower ring 14 while moving along the center axis Y of the coal crusher M. It is designed to rotate in the direction shown by arrow A around Y as an axis.

The lumpy coal 16 supplied by the feed pipe 1 of the coal crusher M falls into the center of the rotating disk 8,
Due to the centrifugal force caused by the rotation of the rotating disk 8, it moves to the circumference of the rotating disk 8. And lump coal 1
6 is a plurality of grinding balls 2 and a lower ring 14;
The pulverized coal 17 is caught between the pulverized coal 17 and the pulverized coal 17, and is discharged to the outer circumference of the lower ring 14.

On the other hand, combustion exhaust gas or heated air (hereinafter referred to as exhaust gas) from a pulverized coal combustion boiler (not shown)
is fed into the wind box 10 at the bottom of the coal crusher M from the exhaust gas supply pipe 4, and the coal crusher M
A ring-shaped rectifier plate 6 installed inside the main body of
and the outer circumferential wall 1 of the lower ring 14.
The liquid is ejected in the direction indicated by arrow X, that is, upward, from the ring-shaped gap formed by 4', that is, the ring-shaped nozzle 7.

The pulverized coal 17 discharged to the outer circumference of the lower ring 14 is blown up by the exhaust gas ejected from the ring-shaped nozzle 7 in the direction shown by the arrow X, and rises within the primary classification zone 3 while being dried. , a classifier 5, and an outlet pipe 9, and are transported to a pulverized coal combustion boiler (not shown).

When the width W of the ring-shaped nozzle 7 is, for example, 5 mm or less, the jetting speed of the exhaust gas jetted from the nozzle 7 is high, but the power of the exhaust gas supply blower (not shown) and the pressure loss of the exhaust gas increase, and
There is a drawback that the nozzle 7 is blocked by the pulverized coal 17. In order to solve such drawbacks, if the width W of the ring-shaped nozzle 7 is set to 5 mm or more, for example,
Pulverized coal 17 falls from the nozzle 7 and accumulates in the wind box 10. The pulverized coal 17 that accumulates in the wind box 10 comes into contact with the exhaust gas supplied from the exhaust gas supply pipe 4 and dries, thereby preventing ignition. Therefore, the accumulated pulverized coal 17 must be carried out, which has been a problem in the past.

[Purpose of the invention]

This invention was made to solve the above problem, and suppresses the pulverized material such as pulverized coal formed in the vertical pulverizer from falling into the nozzle that spouts out the gas for classification. It is an object of the present invention to provide a nozzle device having a structure suitable for this purpose.

[Summary of the Invention] The present invention includes a rotating member that rotates in a plane including a horizontal plane in a crusher, and an upper part of the rotating member that rotates under pressure with respect to the rotating member to crush a material to be crushed. A vertical pulverizer comprising at least a pulverizing member and a nozzle device having an opening for ejecting a gas body from below to upward in order to classify the pulverized material discharged near the outer periphery of the rotating member, A nozzle device is provided in which the gas passage cross-sectional area at the opening of the nozzle device is expanded in a shape that widens toward the end with respect to the gas passage direction.

[Embodiments of the invention]

Embodiments of the invention will be described based on the drawings. FIG. 1 is a diagram showing the cross-sectional shape of the gas supply nozzle of the present invention, and FIG. 2 is a diagram showing the angle of divergence of the gas supply nozzle of the present invention and the amount of pulverized coal falling into the nozzle from the nozzle spout. It is a figure showing a relationship.

As shown in FIG. 1, a ring-shaped nozzle 7 is formed by a lower ring 14 and a ring-shaped current plate 6.
, i.e., the outer circumferential wall 1 of the lower ring 14
4' and the inner circumferential wall 6' of the ring-shaped baffle plate 6 are respectively inclined in the gas passage direction shown by arrow X, so that the gas passage cross-sectional area is widened in the gas passage direction shown by arrow It's getting bigger.

Then, 20 to 25 m ³ / from the nozzle 7 with a width W of 15 mm.
When blowing up pulverized coal with a particle size of 0.1 to 10 mm in the direction shown by arrow
The relationship between the divergence angle θ and the amount of pulverized coal falling into the nozzle 7 in the direction opposite to the direction indicated by the arrow X is shown in FIG. In other words, if the amount of pulverized coal falling into the nozzle 7 in the direction opposite to the direction indicated by arrow The amount of
At 80 degrees, the amount of pulverized coal falling is reduced to less than 1/100.The inner wall of nozzle 7 is sloped in the direction of gas passage shown by arrow The reason why the amount of pulverized coal falling into the nozzle 7 in the direction opposite to the direction indicated by the arrow X is reduced by increasing the width toward the end in the passing direction will be explained in the explanation of FIG. 3a below.

3a, b, c, and d are views showing other embodiments of the present invention, and show, for example, the shape of holes in a perforated plate of a fluidized bed reactor or the like.

In FIG. 3a, the inner walls of the holes 18 of the perforated plate 11 are sloped symmetrically in the gas passage direction indicated by the arrow X so as to widen toward the end. In this case, the gas passing along the inner wall of the hole 18 in the direction shown by the arrow X generates a vortex 13 at the inclined part of the inner wall of the hole 18, and passes through the central part of the hole 18 in the direction shown by the arrow X. The gas jet 12 becomes stable. Therefore, the amount of powder falling from the holes 18 in the direction opposite to the direction indicated by the arrow X is reduced.

FIG. 3b shows that the hole 18 is shaped like a bench lily with a constriction in the direction shown by the arrow X, thereby reducing pressure loss when gas passes through the hole 18 in the direction shown by the arrow X. At the same time, the amount of powder falling from the hole 18 in the direction opposite to the direction indicated by the arrow X is reduced.

3c shows an embodiment in which the slope of the inner wall of the hole 18 is asymmetric, and FIG. 3d shows an embodiment in which the slope of the inner wall of the hole 18 is asymmetric and the flow of gas through the hole 18 is An example is shown in which the direction of is inclined.

Note that the cross-sectional shape of the hole 18 through which the gas passes is not limited to a circular shape, but may be a polygon such as a triangle or a quadrangle, a slit shape, or the like.

[Effects of the Invention] As explained above, the present invention increases the cross-sectional area of gas passage in the gas passage direction by making the inner wall of the gas supply nozzle slope in the gas passage direction. There is. Therefore, the jet of gas passing through the gas supply nozzle is stabilized, so
This has the effect of reducing the amount of powder falling from the gas outlet of the gas supply nozzle into the inside of the gas supply nozzle.

[Brief explanation of drawings]

FIG. 1 is a diagram showing the cross-sectional shape of the gas supply nozzle of the present invention, and FIG. 2 is a diagram showing the angle of divergence of the gas supply nozzle of the present invention and the amount of pulverized coal falling into the nozzle from the nozzle spout. Diagram showing relationships, 3rd
The figure shows another embodiment of the present invention, and FIG. 4 is a diagram showing the schematic structure of a conventional vertical ball type coal crusher. 1... Coal feed pipe, 2... Grinding ball, 3... Primary classification zone, 4... Exhaust gas supply pipe, 5... Classifier, 6... Straightening plate, 6'... Inner circumferential wall, 7... Nozzle, 8... Rotating circle Plate, 9... Outlet pipe, 10... Wind box, 11
... Perforated plate, 12 ... Jet flow, 13 ... Vortex, 14 ... Lower ring, 14' ... Outer circumferential wall, 15 ... Upper ring,
16... Lump coal, 17... Pulverized coal, 18... Holes.

Claims (1)

[Claims] 1. A rotating member that rotates in a plane including a horizontal plane within the crusher, a crushing member that rotates under pressure with respect to the rotating member to crush the object to be crushed, and a crushing member that is placed above the rotating member and crushes the object to be crushed. In a vertical crusher equipped with at least a nozzle device having an opening for ejecting a gas body from below upward in order to classify the crushed material discharged near the outer periphery of the machine, the gas at the opening of the nozzle device is A vertical crusher characterized by being provided with a nozzle device whose passage cross-sectional area is widened toward the end in the gas passage direction.