JPH10151361A - Pyrite discharging device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To surely keep water seal effect irrespective of operating conditions of a pulverized coal mill. SOLUTION: In this device, there is provided a hopper 25 to whose upper part, a pyrite discharging pipe 23 for discharging pyrite (a) from a primary air chamber of a pulverized coal mill is connected and which is provided with a jet valve 30 for conveying the pyrite (a) by water to the outside thereunder. A water seal device 31 for keeping internal pressure of the hopper 25 by seal water 36 is connected to the upper part of the hopper 25, and an overflow pipe 41 is connected to the upper part of the water seal device 31. And to the lower part of the water seal device 31, a seal water supply path 37 with a stop valve 38 for replenishing the seal water 36 when the water level is lowered is connected. Furthermore, to the seal water supply path 37, a valve 48 normally held slightly open is connected in parallel with the stop valve 38.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pyrite discharging device, and more particularly to a pyrite discharging device capable of surely maintaining a water sealing effect regardless of the operation state of a pulverized coal mill. is there.

[0002]

2. Description of the Related Art For example, in a coal-fired boiler, pulverized coal obtained by pulverizing coal is supplied to a burner as fuel and burned.

[0003] A pulverized coal mill is used to pulverize coal.

[0004] The pulverized coal mill is as shown in FIG. 4. First, a pulverizing motor 3 and a speed reducer 4 are provided below a pulverizing chamber 2 formed in a mill body casing 1 having a substantially cylindrical shape. And a pair of crushing rollers 7 (only two crushing rollers are shown in FIG. 4) pressed against a ring-shaped groove 6 formed on the crushing table 5. ) To constitute the crushing mechanism 8.

[0005] Above the outside of the mill body casing 1,
A conveyer-type coal feeder 10 for transporting raw coal 9 stored in a bunker (not shown) is provided, and a raw coal inlet pipe 11 connected to the outlet side of the coal feeder 10 and extending vertically downward is provided with The pulverized coal 12 and the coarse coal 13 from the raw coal 9 pulverized by the pulverizing mechanism 8 are inserted into the raw coal inlet pipe 11 at the outer periphery of the upper part of the mill main casing 1 while being inserted into the axial center position of the mill main casing 1. A classifier 14 for classifying is provided.

Further, a primary air chamber 15 is formed below the pulverizing chamber 2 of the mill body casing 1, and raw coal 9 finely pulverized by the pulverizing table 5 is provided between the primary air chamber 15 and the pulverizing chamber 2.
Is provided by a primary air 16 to a classifier 14 above.

[0007] In the figure, reference numeral 18 denotes a swirling force imparting vane attached to a raw coal inlet slit formed on the outer periphery of the classifier 14, 19 denotes a coarse powder outlet formed at a lower portion of the classifier 14, 20. Is a fine powder outlet formed at the upper part of the classifier 14;
Reference numeral 1 denotes pulverized coal 12 and coarse coal 1 disposed inside a classifier 14.
This is a classification cylinder for classifying No.3.

In the above-mentioned pulverized coal mill, raw coal 9 stored in a bunker (not shown) is conveyed by a conveyor of a coal feeder 10, dropped through a raw coal inlet pipe 11, and positioned at the center of the mill main casing 1. Is supplied to the upper surface of the pulverizing table 5 provided in the above.

The crushing table 5 includes a crushing motor 3
The raw coal 9 dropped by a set of three crushing rollers 7, which is rotationally driven via a speed reducer 4 and pressed against a ring-shaped concave groove 6 on the top of the crushing table 5, is finely crushed. You.

The finely pulverized raw coal 9 is supplied to the primary air port 1
While being dried by the primary air 16 blown from 7, it is blown up inside the mill main casing 1.

The raw coal 9 blown upward from the mill main casing 1 enters a classifier 14 and is classified by the classifier 14, and the light pulverized coal 12 passes through a fine powder outlet 20 formed at the top of the classifier 14. The heavy coal pulverized coal 13 is taken out, dropped from the coarse powder outlet 19 formed in the lower part of the classifier 14 onto the pulverizing table 5, and pulverized again.

The raw coal 9 contains foreign substances called pyrite a, such as pyrite, iron and stone, which cannot be pulverized by the pulverizing mechanism 8. The pyrite a is pushed out of the pulverizing table 5. It falls into the primary air chamber 15, is scraped off by a scraper 22 disposed on the lower surface of the crushing table 5, and is sent to a hopper 25 of a pyrite discharging device 24 via a pyrite discharging pipe 23.

As shown in FIG. 5, the pyrite discharge device 24 includes a gate 27 which can be opened and closed by a driving device 26 such as a cylinder in the middle of the pyrite discharge pipe 23.
A hopper outlet valve 28 and a jet water 29 are provided below the hopper 25.
, A jet valve 30 capable of transporting the pyrite a in the hopper 25 by water is attached.

Further, a water seal device 31 for maintaining the internal pressure is connected to an upper portion of the hopper 25.

The water seal device 31 has one end connected to the upper portion of the hopper 25, the other end extending vertically downward and having an opening 32 at the lower end, and a water seal tube 33 at the other end. A seal pot 35 for accommodating and surrounding the vertical portion 34; an overflow pipe 41 having one end connected to the upper portion of the seal pot 35 and the other end extending downward; 36 pump 4
5, a seal water supply path 37 for replenishing the inside of the seal water 35, an on-off valve 38 provided in the middle of the seal water supply path 37, and a height from the lower end of the seal pot 35 to the overflow pipe 41 mounting position. It is installed at a height of approximately 70 to 80% and seal water 3 in seal pot 35 is provided.
6 to receive a water level detector 40 such as a limit switch that sends an open signal 39 to the on-off valve 38 when the water level is lower than the mounting position by detecting the water level, and an opening 42 at the other end of the overflow pipe 41. A receiving container 43 disposed,
The seal water 36 received by the receiving container 43 is transferred to the seal water tank 4.
4 and a seal water return path 46.

In the pyrite discharging device 24, foreign substances called pyrite a, such as pyrite, iron and stone, which cannot be pulverized by the pulverizing mechanism 8, are contained in the raw coal 9.
The pyrite discharging device 2 is scraped off from the grinding table 5 by the scraper 22 and is passed through the pyrite discharging pipe 23.
After being sent to the hopper 25 of No. 4, it is stored in the hopper 25, and is transported from the lower part of the hopper 25 by the jet water 29 via the hopper outlet valve 28 and the jet valve 30.

When the gate 27 is opened by the driving device 26, the hopper 25 communicates with the primary air chamber 15 through the pyrite discharge pipe 23, so that a positive pressure on the pulverized coal mill side is applied. Is connected and sealed with water so that the internal pressure can be maintained.

That is, when the internal pressure of the primary air chamber 15 sharply increases from the state shown in FIG. 5, the internal pressure of the space above the hopper 25 also increases, so that the downward pressure is applied to the upper surface of the seal water 36 in the water seal tube 33. Works. For this reason, as shown in FIG. 6, the water surface in the vertical portion 34 of the water seal tube 33 descends, and the water surface of the seal water 36 in the seal pot 35 rises outside the water seal tube 33. When the level of the seal water 36 in the pipe 35 rises to the connection portion of the overflow pipe 41 to the seal pot 35, the seal water 36 in the seal pot 35 is discharged to the receiving container 43 through the overflow pipe 41.

Thereafter, when the internal pressure of the primary air chamber 15 sharply decreases, the internal pressure of the hopper 25 and the internal pressure of the water seal tube 33 also decrease. Therefore, as shown in FIG. The water level of the seal water 36 in the part 34 rises,
Outside 3, the surface of the seal water 36 in the seal pot 35 descends.

As described above, when the pressure in the primary air chamber 15 is repeatedly increased and decreased, the water level in the seal pot 35 gradually decreases, and in extreme cases, the water level of the seal water 36 in the seal pot 35. However, there is a possibility that the water sealing effect may be lost because the water sealing pipe 33 is lower than the opening 32 at the lower end of the vertical portion 34.

For this reason, the water level of the seal water 36 in the seal pot 35 is detected by the water level detector 40 such as a limit switch, and when the water level falls below the mounting position of the water level detector 40 such as the limit switch, the opening and closing is performed. An open signal 39 is sent to the valve 38 to open the on-off valve 38, and the water level of the seal water 36 in the seal water tank 44 is limited into the seal pot 35 through the seal water supply path 37 using the pump 45. The water is supplied so as to be in the state of FIG. 5 above the mounting position of the water level detector 40 such as a switch.

The seal water 3 discharged into the receiving container 43
6 is a seal water tank 44 via a seal water return path 46.
It is returned to and used cyclically.

[0023]

However, the conventional pyrite discharging device has the following problems.

That is, the seal water 36 in the seal pot 35
Since the water level of the seal water may fluctuate greatly depending on the operation state of the pulverized coal mill, the water level of the seal water 36 in the seal pot 35 is detected by a water level detector 40 such as a limit switch, and the water level is switched when the water level falls. If the seal water 36 is supplied by operating the valve 38, the water level may not be recovered in time.

As described above, if the water sealing effect of the water sealing device 31 is lost due to the replenishment of the sealing water 36 in time, the pressure in the hopper 25 is reduced and a part of the primary air 16 is reduced to the primary air chamber. 15 and the pyrite discharge pipe 23, flows into the hopper 25, flows out of the hopper 25 through the water seal pipe 33, the seal pot 35, and the overflow pipe 41, and the primary air 16 in the primary air port 17 is accordingly reduced. Since the flow rate is reduced and the flow rate is reduced, the raw coal 9 finely pulverized on the pulverizing table 5 cannot be blown up to the upper classifier 14, so that the operation of the pulverized coal mill has to be stopped. This will lead to situations that cannot be obtained.

The present invention has been made in view of the above circumstances, and has as its object to provide a pyrite discharging device capable of reliably maintaining a water sealing effect even when the level of sealing water in a sealing pot fluctuates drastically. Things.

[0027]

According to the present invention, a pyrite discharge pipe 23 for discharging pyrite a from a primary air chamber of a pulverized coal mill is connected to an upper portion so that the pyrite a can be transported to the outside by water. A hopper 25 having a jet valve 30 attached to a lower portion thereof is provided, and a water seal device 31 configured to maintain an internal pressure of the hopper 25 by a seal water 36 is connected to an upper portion of the hopper 25, and overflows to an upper portion of the water seal device 31. A pipe 41 is connected, and a seal water supply path 37 having an on-off valve 38 for refilling the seal water 36 when the water level is lowered is connected to a lower part of the water seal device 31. And a valve 48 which is always kept in a slightly open state so as to be in parallel with the on-off valve 38.

According to the above means, the following effects can be obtained.

In the water sealing device 31, if the water level of the sealing water 36 in the water sealing device 31 becomes low, the water sealing effect will be cut off. 36 is supplied into the water sealing device 31 via the seal water supply path 37.

However, since the water level of the seal water 36 in the water seal device 31 may fluctuate drastically depending on the operation state of the pulverized coal mill, the seal water 36 is operated by operating the on-off valve 38 when the water level decreases. If you try to replenish, there are times when it is not in time.

As described above, when the replenishment of the sealing water 36 is not in time, the water sealing effect of the water sealing device 31 is cut off, the pressure in the hopper 25 is reduced, and a part of the primary air in the pulverized coal mill is reduced. Will flow into the hopper 25 through the primary air chamber and the pyrite discharge pipe 23, and the flow rate of the primary air in the primary air port of the pulverized coal mill will be reduced accordingly. To
As a result, the pulverized coal mill cannot be blown up to the upper classifier, and the operation of the pulverized coal mill must be stopped.

Therefore, in the present invention, the seal water supply path 37
By connecting a valve 48 which is always kept slightly open so as to be in parallel with the on-off valve 38,
8, the seal water 36 is always sent into the water seal device 31 and the seal water 36 is caused to overflow from the overflow pipe 41, and the water level of the seal water 36 in the water seal device 31 is set to the connection position of the overflow pipe 41, That is, the highest level is maintained.

As described above, the sealing water 3 in the water sealing device 31
6 is maintained at the highest level, so that the sealing water 36 can be severely affected by the operation of the pulverized coal mill.
Even if a situation where the water level of the seal water 36 fluctuates occurs, the water level of the seal water 36 before the fluctuation was at the highest level, and the amount of the seal water 36 constantly sent into the water sealing device 31. However, it is possible to secure a margin time necessary for the supply of the seal water 36 by the on-off valve 38 in time, and it is possible to reliably maintain the water sealing effect.

[0034]

Embodiments of the present invention will be described below with reference to the drawings.

FIGS. 1 to 3 show an embodiment of the present invention.

The basic structures of the pulverized coal mill and the pyrite discharging device are the same as those shown in FIGS. 4 and 5, and the same parts are denoted by the same reference numerals and description thereof will be omitted.

One end of the seal water supply channel 37 is connected to the upstream side in the flow direction of the seal water 36 from the position where the on-off valve 38 is installed, and the seal water supply passage 37 is connected to the seal water 36 in the flow direction from the installation position of the on-off valve 38 A seal water bypass flow path 47 having the other end connected to the downstream side of the seal water bypass flow path 47 is provided. Connected valve 48,
During the operation, the seal water 36 can always be supplied into the seal pot 35.

The valve 48, which is always kept in a slightly open state, may have a fixed opening such as an orifice, but may have an opening such as an opening adjusting valve. It is preferable that the degree can be set.

Next, the operation will be described.

In this embodiment, the discharge of pyrite from the pulverized coal mill to the hopper 25 and the transport of pyrite a from the hopper 25 are carried out in the same manner as in the conventional case.

In the water sealing device 31, if the water level of the sealing water 36 in the sealing pot 35 becomes lower than the opening 32 at the lower end of the vertical portion 34 of the water sealing tube 33, the water sealing effect will be cut off. Water level detector 40 such as limit switch
To detect the water level of the seal water 36 in the seal pot 35, and when the water level falls below the mounting position of the water level detector 40 such as a limit switch, the open signal 3 is sent to the on-off valve 38.
9 to open the on-off valve 38 and set the seal water tank 44
The seal water 36 is supplied to the seal pot 35 by using the pump 45 through the seal water supply path 37 so that the water level is higher than the mounting position of the water level detector 40 such as a limit switch. ing.

However, the seal water 3 in the seal pot 35
Since the water level of No. 6 may fluctuate drastically depending on the operation state of the pulverized coal mill, the water level of the seal water 36 in the seal pot 35 is detected by the water level detector 40 such as a limit switch. If the seal water 36 is replenished by operating the on-off valve 38, it may not be in time.

As described above, when the replenishment of the sealing water 36 is not in time, and the water sealing effect of the water sealing device 31 is lost, the pressure in the hopper 25 is reduced and a part of the primary air in the pulverized coal mill is reduced. Flows into the hopper 25 through the primary air chamber and the pyrite discharge pipe 23, and the water seal pipe 3
3. It flows out through the seal pot 35 and the overflow pipe 41 to the outside, and the flow rate of the primary air 16 in the primary air port 17 of the pulverized coal mill is reduced correspondingly, so that the flow velocity is reduced. In this case, the raw coal 9 pulverized by the above method cannot be blown up to the upper classifier 14, and the operation of the pulverized coal mill must be stopped.

Therefore, in the present invention, the seal water supply path 37
By connecting a valve 48 which is always kept slightly open so as to be in parallel with the on-off valve 38,
The seal water 36 from the pump 45 is constantly sent into the seal pot 35 through the seal water 35, as shown in FIG.
6 overflows from the overflow pipe 41,
The level of the seal water 36 in the seal pot 35 is maintained at the connection position of the overflow pipe 41, that is, at the highest level.

As described above, by maintaining the water level of the seal water 36 in the seal pot 35 at the highest level, a situation in which the water level of the seal water 36 fluctuates drastically depending on the operation state of the pulverized coal mill. Even if it occurs, replenishment of the seal water 36 by the opening / closing valve 38 is equivalent to the level of the seal water 36 before the fluctuation, which was at the highest level, and the amount that the seal water 36 is always sent into the seal pot 35. , It is possible to secure a margin time necessary to make the time, and it is possible to reliably maintain the water sealing effect.

Specifically, when the internal pressure of the primary air chamber 15 rises sharply from the state where the seal water 36 overflows as shown in FIG. 1, the internal pressure of the space above the hopper 25 also rises. A downward pressure acts on the upper surface of the seal water 36 in the inside 33. For this reason, as shown in FIG. 2, the water surface in the vertical portion 34 of the water seal tube 33 descends, but the water surface of the seal water 36 in the seal pot 35 outside the water seal tube 33 is at the connection position of the overflow pipe 41. At this time,
The amount of the seal water 36 discharged to the receiving container 43 through the overflow pipe 41 increases.

Thereafter, when the internal pressure of the primary air chamber 15 suddenly decreases, the internal pressure of the hopper 25 and the internal pressure of the water seal tube 33 also decrease. Therefore, as shown in FIG. The water level of the seal water 36 in the part 34 rises,
Outside 3, the surface of the seal water 36 in the seal pot 35 descends.

However, the water surface of the seal water 36 in the vertical portion 34 of the water seal tube 33 when it descends, and the water surface of the seal water 36 in the seal pot 35 outside the water seal tube 33,
Since the seal water 36 is always supplied into the pump 5, the supply of the water 36 may be continuously continued from the time when the water level detector 40 such as a limit switch detects to the time when the on-off valve 38 is opened. Since the water level is higher than the water level in FIG. 7 (indicated by the phantom line in FIG. 3), the seal water 36 is replenished from the opening of the on-off valve 38 to the mounting position of the water level detector 40 such as a limit switch. The time required for the water sealing effect can be shortened, thereby expanding the range in which the water sealing effect can be maintained.

It should be noted that the seal water 3 up to the mounting position of the water level detector 40 such as a limit switch by the on-off valve 38 is set.
After the replenishment of No. 6 is completed, the water level of the seal water 36 inside the seal pot 35 outside the water seal tube 33 is changed by the seal water 36 constantly supplied from the valve 48 which is always kept slightly open. Is the connection position of the overflow pipe 41,
That is, it is restored to the highest level again and returns to the overflow state.

Further, the valve 48, which is always kept in the slightly open state, may be a valve whose opening is fixed to a fixed value, such as an orifice.
The time until the level of the seal water 36 reaches the maximum level can be adjusted during manufacturing or thereafter.

It should be noted that the present invention is not limited to only the above-described embodiment, and it is needless to say that various changes can be made without departing from the scope of the present invention.

[0052]

As described above, according to the pyrite discharging apparatus of the present invention, an excellent effect that the water sealing effect can be reliably maintained regardless of the operation state of the pulverized coal mill can be obtained.

[Brief description of the drawings]

FIG. 1 is a schematic side sectional view of an example of an embodiment of the present invention.

FIG. 2 is a view similar to FIG. 1, showing a state in which the internal pressure of the primary air chamber has rapidly increased.

FIG. 3 is a view similar to FIG. 1, showing a state in which the internal pressure of the primary air chamber has rapidly dropped.

FIG. 4 is a schematic side sectional view of a pulverized coal mill.

FIG. 5 is a schematic side sectional view of a conventional example in which FIG. 4 is enlarged.

FIG. 6 is a view similar to FIG. 5, showing a state in which the internal pressure of the primary air chamber is rapidly increased.

FIG. 7 is a view similar to FIG. 5, showing a state in which the internal pressure of the primary air chamber has rapidly dropped.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Pulverized coal mill (mill main casing) 15 Primary air chamber 23 Pyrite discharge pipe 25 Hopper 29 Jet water 30 Jet valve 31 Water seal device 36 Seal water 37 Seal water supply path 38 Open / close valve 41 Overflow pipe 48 Valve a Pyrite

Claims (1)

[Claims] 1. A jet valve having a pyrite discharge pipe (23) for discharging pyrite (a) from a primary air chamber of a pulverized coal mill connected to an upper portion thereof so that the pyrite (a) can be transported to the outside by water. A hopper (25) attached to the lower part of (30) is provided, and a water sealing device (31) connected to the upper part of the hopper (25) so as to maintain the internal pressure of the hopper (25) by seal water (36). And a water seal device (3
An overflow pipe (41) is connected to the upper part of (1), and a seal water provided with an open / close valve (38) at the lower part of the water seal device (31) for replenishing seal water (36) when the water level drops. The supply path (37) was connected, and further, the seal water supply path (37) was connected to a valve (48) which was always kept in a slightly open state so as to be in parallel with the on-off valve (38). Features a pyrite discharge device.