JP2008111586A - Operating method for automatically burning coal bunker completely in thermal power system and its system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To allow an operator in a central control room to easily, safely and quickly perform the operation of burning coal in a coal bunker completely by automatically closing a coal gate valve when the amount of coal in the coal bunker reaches a zero level after the bunker is operated with the amount of coal for complete burning, and then automatically stopping a coal feeder. <P>SOLUTION: An operating method for automatically burning a coal bunker completely in a thermal power system includes: monitoring the amount of coal in the coal bunker 10 with a level gauge; automatically reducing the amount of coal fed by a coal feeder 14, so that the amount of coal for complete burning is reached; when the amount of coal reaches the zero level, automatically closing a coal gate valve 15 provided in a supply passage 13 extending from the coal bunker 10 to the coal feeder 14; and automatically stopping the coal feeder 14. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a method and system for automatically cutting a coal bunker in a thermal power generation system.

In a coal-fired power plant, it is necessary to stop the operation at any time or inspecting a plant in response to weather conditions such as bad weather or lightning strikes, and power consumption conditions. At that time, if coal is stored in the coal bunker for a long time, the coal may spontaneously ignite. Therefore, when the plant is stopped for a long time, it is safer to stop the coal in the coal bunker before it is stopped.
In addition, since the chopping is performed while the plant is operating, not only stopping the coal supply to the bunker to be chopped off, but if the amount of coal supplied from the target bunker to the boiler is not adjusted, The change in quantity becomes large, and abnormal conditions may occur in the entire plant. Therefore, by reducing the coal supply amount of the target coal feeder to the minimum coal supply amount according to the bunker level and applying fuel control weight to other mills or other fuel facilities, the impact on the plant due to chopping is reduced. Must be minimized.

  Conventionally, the coal bunker chopping operation at a coal-fired power plant monitors the coal level in the bunker visually at the site, and communicates between the site and the central control room. In response to a command from the room, the amount of coal supplied by the coal feeder was reduced, and the call gate valve was closed at the same time as a bunker level zero notification was made on site.

  For this reason, there is a problem that a large number of personnel are required on the site, and there are many places depending on human experience, and the operator concentrates on the cutting operation, and the monitoring consciousness of other units is reduced.

  Accordingly, the present invention provides a boiler coal supply in which coal in a coal bunker is supplied to a mill via a coal feeder, and coal dusted by the mill is mixed with hot air and supplied to a boiler coal burner. In a thermal power generation system that has a system, the amount of coal in the coal bunker is monitored with a level meter, and when the amount of coal reaches a predetermined level of starting cutting, Coal gate valve provided in the supply path that reaches the coal feeder from the coal bunker when the coal amount in the coal bunker reaches the zero level by automatically reducing the coal supply amount so that the coal supply amount is reduced. Is provided, and a coal bunker automatic cutting operation method and system for a thermal power generation system in which the coal feeder is automatically shut down and then the coal feeder is automatically stopped are provided.

  The present invention also relates to the coal bunker automatic chopping operation method in the above-described thermal power generation system, wherein the chopped coal supply amount of the coal feeder is set to the minimum coal supply amount that can be supplied to the boiler. A bunker automatic cutting method and its system are provided.

  Further, the present invention provides a thermal power generation system in which, in the above-described coal bunker automatic chopping operation method in the thermal power generation system, the chopped coal supply amount of the coal feeder is set to about half of the coal supply amount during normal operation. A coal bunker automatic chopping operation method and system are provided.

  Further, the present invention provides an automatic coal bunker cutting operation method in the above-described thermal power generation system, wherein the coal bunker automatic in the thermal power generation system is configured to monitor the amount of coal in the coal bunker with a level meter provided at the upper part of the coal bunker. A cutting operation method and a system thereof are provided.

  The present invention also provides an automatic coal bunker cutting operation method in a thermal power generation system in which the level meter is an ultrasonic method in the coal bunker automatic cutting operation method in the above-described thermal power generation system.

  Further, the present invention provides a thermal power generation system in which the amount of coal in the coal bunker is monitored by a low level monitoring level meter provided in the lower part of the coal bunker in the coal bunker automatic cutting operation method in the thermal power generation system described above. An automatic coal bunker cutting method and its system in the system are provided.

  The present invention also provides an automatic coal bunker chopping operation method in a thermal power generation system in which the mill is stopped after stopping the coal feeder in the coal bunker automatic chopping operation method in the thermal power generation system described above. Is.

  According to the coal bunker automatic chopping operation method and the system in the thermal power generation system according to the present invention, the coal in the coal bunker is supplied to the mill via the coal feeder, and the coal dusted by the mill is mixed with hot air. In a thermal power generation system having a boiler coal supply system that is supplied to the coal burner of the boiler, the amount of coal in the coal bunker is monitored with a level meter, and the amount of coal has reached a predetermined level of chopping. By the way, the amount of coal supplied from the coal feeder is automatically reduced at a predetermined rate so as to reach a predetermined amount of chopped coal, and the amount of coal in the coal bunker reaches zero level by operating at the amount of chopped coal. In the central control room, the coal gate valve provided in the supply path from the coal bunker to the coal feeder is automatically closed and then the coal feeder is automatically stopped. The amount of coal in the bunker can be monitored with a level meter, so when the amount of coal reaches the predetermined level of chopping, the amount of coal supplied by the coal feeder becomes a predetermined amount of chopped coal at a predetermined rate. It can be controlled to decrease automatically, and when the amount of coal in the coal bunker reaches zero level by operating with a chopped coal supply amount, a call gate valve provided on the supply path from the coal bunker to the coal feeder is installed. By automatically closing and then automatically shutting off the coal feeder, there is no need for a large number of personnel on-site, and operators can easily, safely and quickly cut through the central control room without relying on human experience. There is an effect that can.

  Further, according to the present invention, in the coal bunker automatic chopping operation method in the thermal power generation system and the system, the chopping coal supply amount of the coal feeder is set to the minimum coal supply amount that can be supplied to the boiler. When the coal amount in the coal bunker reaches zero level by operating at the minimum coal supply amount at the time of cutting, when the call gate valve provided in the supply path from the coal bunker to the coal feeder is closed, There is an effect that coal supply by the coal feeder can be quickly stopped.

  Further, the present invention provides a method for automatically chopping a coal bunker in the above-described thermal power generation system and the system thereof, wherein the chopping amount of the coal feeder is set to about half of the amount of coal supply during normal operation. By having the above, there is an effect that the generated power can be easily adjusted during the chopping operation with respect to the normal operation.

  Further, the present invention has a configuration in which the amount of coal in the coal bunker is monitored by a level meter provided in the upper part of the coal bunker in the coal bunker automatic cutting operation method and the system in the thermal power generation system described above. Thus, there is an effect that the amount of coal in the bunker can be monitored over a wide measurement range from the top to the bottom.

  Further, the present invention provides a method for automatically chopping a coal bunker in the above-described thermal power generation system, and the system thereof, since the level meter has an ultrasonic method, so that the amount of coal in the bunker can be measured from the top to the bottom. There is an effect that can be monitored over.

  Further, according to the present invention, in the coal bunker automatic cutting operation method in the thermal power generation system and the system, the amount of coal in the coal bunker is monitored by a level meter for low level monitoring provided in the lower part of the coal bunker. With this configuration, there is an effect that it is possible to improve the accuracy of level grasp at the low level.

  Further, the present invention provides a method for automatically cutting a coal bunker in the above-described thermal power generation system and the system thereof, wherein the mill is stopped after stopping the coal feeder, thereby preventing the reverse flow of coal dust due to the internal pressure of the mill. There is an effect that can be prevented.

  The present invention will be described below with reference to the illustrated embodiments.

In FIG. 1, reference numeral 10 denotes a coal bunker, which includes an upper main bunker 11 and a lower sub bunker 12, and is configured such that coal supply is supplied from the sub bunker 12 through a supply path 13 to a coal feeder 14.
In the coal feeder 14, a conveyor capable of automatically controlling the amount of coal supply by remote control of the central control room is incorporated. The conveyor is composed of, for example, a belt conveyor provided with a coal feed amount detection unit including a belt travel distance detection unit and a load detection unit. It is comprised so that it can control.
The coal supplied to the mill from the coal feeder 14 is configured to be dusted, mixed with hot air, and supplied to the coal burner of the boiler.

  In the case of the embodiment, an ultrasonic type level meter that monitors the amount of coal from above is provided on the upper portion of the coal bunker 10 and can measure the remaining amount of coal from about 0 m to about 25 m. The remaining amount of coal is about 8.5m at the boundary between the main bunker 11 and the sub-bunker 12, and is set at the start level at about 2.0m, and at the zero level at 0m, and can be monitored in the central control room. It is.

  A call gate valve 15 is provided in the supply path 13 from the sub-bunker 12 to the coal feeder 14, and the central control room C receives a zero level monitoring signal L0 from the level meter L as shown in FIG. Then, a command signal C0 for automatically closing the supply path is sent to the call gate valve 15 so as to be automatically closed.

  In addition to the above level meter, a level transmitter is attached to the sub-bunker 12 so that the level in the sub-bunker 12 can be monitored more precisely in the central control room. It is also possible to reduce the amount of coal supply by a control circuit that reduces the amount of coal, and at the same time, close the call gate valve 15 at zero level.

  Next, based on FIG. 3 and FIG. 4, the coal bunker automatic cutting method and the system in the thermal power generation system will be described. When the level of the level meter L of the coal bunker 10 becomes about 10.0 m, FIG. In step S1, an alarm means for alarming the central control room C that the amount of coal in the coal bunker has reached a low level is activated, and whether or not to perform the bunker cutting operation. Then, when the level of the level meter L reaches about 8.5 m, as shown in step S2, a bunker cutting preparation stage is entered, and a program specifically related to cutting is set up. .

  Subsequently, when the level of the level meter L reaches about 2.0 m as described in step S3 of FIG. 3, the level of the bunker cutting start level is transferred from the level meter L to the central control room C as illustrated in FIG. A signal L2 is generated, the bunker cutting system is activated, and a control circuit for generating a control signal C2 for reducing the coal supply amount to the coal feeder 14 at a predetermined rate works, for example, the coal supply amount during normal operation until then. The control of the coal feeder 14 was started so as to halve the coal supply amount to 15 ton / h after a predetermined time until the amount of coal supply was 15 ton / h. Once reached, the coal supply is maintained at 15 ton / h.

In the case of the embodiment, the chopped coal supply amount 15 ton / h of the coal feeder 14 is set to the minimum coal supply amount that can be supplied to the boiler, and by operating at the minimum coal supply amount at the time of chopping, When the coal amount in the coal bunker 10 reaches the zero level, when the coal gate valve 15 provided in the supply path 13 from the coal bunker to the coal feeder 14 is closed, the coal feeder 14 quickly stops the coal supply. There is an effect that can be done.
In addition, since the amount of chopped coal supply of the coal feeder 14 is set to about half of the amount of coal supplied during normal operation, it is possible to easily adjust the generated power during the chopping operation relative to the normal operation. There is.

When the level meter L detects 0 m as shown in step 5 of FIG. 3 by the operation of the coal feeder 14 at the subsequent cut-off coal supply amount of 15 ton / h, as shown in FIG. The signal L0 is transmitted to the central control room C, the coal supply stop signal C0 of the bunker cutting system is activated, the call gate valve 15 is automatically closed, the supply to the coal feeder 14 is stopped, and then step 6 As described in, the coal feeder 14 stops.
Thereafter, the mill stops and the supply of coal dust to the coal burner is also stopped.

The schematic explanatory drawing of the coal bunker system concerning the present invention. The schematic explanatory drawing of one Example of the bunker cutting system. The flowchart which shows the outline of the one operation mode of the system.

Explanation of symbols

10 Coal bunker 11 Main bunker 12 Sub bunker 13 Supply channel 14 Coal feeder 15 Coal gate valve L Level meter C Central control room

Claims (14)

Coal bunker coal is supplied to the mill via a coal feeder, and coal is pulverized by the mill and mixed with hot air to supply the boiler coal burner. In the system, the amount of coal in the coal bunker is monitored with a level meter, and when the amount of coal reaches the predetermined start level, the coal supply amount of the coal feeder becomes the predetermined amount of cut at a predetermined rate. When the amount of coal in the coal bunker reaches zero level, the coal gate valve provided in the supply path from the coal bunker to the coal feeder is automatically closed. Then, a coal bunker automatic cutting operation method in a thermal power generation system that automatically stops the coal feeder. The coal bunker automatic chopping operation method in the thermal power generation system according to claim 1, wherein the coal bunker automatic chopping amount of the coal feeder is set to a minimum coal supply amount that can be supplied to the boiler. Cutting operation method. In the coal bunker automatic chopping operation method in the thermal power generation system according to claim 1 or 2, in the thermal power generation system in which the chopping coal supply amount of the coal feeder is set to about half of the coal supply amount during normal operation. Coal bunker automatic chopping operation method. The coal bunker automatic cutting operation method in the thermal power generation system according to claim 1, 2, or 3, wherein the coal in the thermal power generation system is configured to monitor the amount of coal in the coal bunker with a level meter provided on the upper part of the coal bunker. Bunker automatic cutting operation method. The coal bunker automatic cutting operation method in the thermal power generation system according to claim 4, wherein the level meter is an ultrasonic type coal bunker automatic cutting operation method. In the coal bunker automatic cutting operation method in the thermal power generation system according to any one of claims 1 to 5, the amount of coal in the coal bunker is monitored with a level meter for low level monitoring provided at a lower portion of the coal bunker. Of automatic coal bunker cutting in a thermal power generation system. The automatic coal bunker cutting operation method in the thermal power generation system according to any one of claims 1 to 6, wherein the mill is stopped after the coal feeder is stopped. Coal bunker coal is supplied to the mill via a coal feeder, and coal is pulverized by the mill and mixed with hot air to supply the boiler coal burner. In the system, a means to monitor the amount of coal in the coal bunker with a level meter, and when the coal amount reaches the predetermined cutting start level by taking the output of the level meter, the coal supply amount of the coal feeder at a predetermined rate Means to control to automatically reduce so as to achieve a predetermined chopped coal supply amount, and the operation of the chopped coal supply amount is continued and the output of the level meter reaches the zero level in the coal bunker By the way, an automatic coal bunker cutting operation system in a thermal power generation system comprising means for automatically closing a coal gate valve provided in a supply path from the coal bunker to the coal feeder and means for automatically stopping the coal feeder. . The automatic coal bunker cutting operation system in the thermal power generation system according to claim 8, wherein the chopping coal supply amount of the coal feeder is set to a minimum coal supply amount that can be supplied to the boiler. Cutting operation system. In the coal bunker automatic chopping operation system in the thermal power generation system according to claim 8 or 9, in the thermal power generation system in which the chopping coal supply amount of the coal feeder is set to about half of the coal supply amount during normal operation. Coal bunker automatic chopping operation system. The coal bunker automatic cutting operation system in the thermal power generation system according to claim 8, 9 or 10, wherein the coal in the thermal power generation system is configured to monitor the amount of coal in the coal bunker with a level meter provided on the upper part of the coal bunker. Bunker automatic cutting operation system. The coal bunker automatic cutting operation system in the thermal power generation system according to claim 11, wherein the level meter is an ultrasonic type coal bunker automatic cutting operation system. In the coal bunker automatic cutting operation system in the thermal power generation system according to any one of claims 8 to 12, the amount of coal in the coal bunker is monitored by a low level monitoring level meter provided at a lower portion of the coal bunker. Coal bunker automatic chopping operation system in a thermal power generation system. The coal bunker automatic cutting operation system in the thermal power generation system according to any one of claims 8 to 13, wherein the mill is stopped after the coal feeder is stopped.

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