JPS5974423A - Fuel control method of powdered coal combustion furnace - Google Patents

Abstract

PURPOSE:To make it possible to respond immediately to an additional combustion requirement command and a fire extinguishing command by a method wherein a circuit device adopted to store powdered coal temporarily is provided in a bypass passage formed in a fuel pipe for introducing the powdered coal to a burner of the furnace from a powdered coal device. CONSTITUTION:Powdered coal is introduced to the burner 6 of the combustion furnace such as a boiler through the fuel pipe 4 as it floats on a current of preheated air 3. When a generator output command 12 increases, the additional combustion requirement command 19 is generated from a boiler control device 11 to a damper control device 21 whereupon a damper drive device 22 corresponding to a required mill 1 is turned ON, a damper 9 is opened while a damper 10 is closed and the supply of the powdered coal flowing through a bypass pipe 7 is switched to the burner 6. Further, when the generator output command 12 decreases rapidly or is stopped, the quick fire extinguishing command 20 is generated to the damper control device 21 whereupon the damper drive device 20 corresponding to the required mill 1 is turned OFF, the dampers 9 and 10 are opened and at the same time, the supply of coal 2 to the mill 1 is stopped. In addition, the mill 1 which corresponds to the fire extinguished burner 6 continues to supply the powdered coal to a powdered coal collecting device 8 through the bypass pipe 7 until the interior of the mill 1 becomes empty and the operation of the mill is stopped when mill is emptied.

Description

[Detailed description of the invention] The present invention relates to a fuel control method for a pulverized coal furnace.

In recent years, due to the worsening fuel situation, various ideas have been given to using pulverized coal as fuel in furnaces such as boilers. The charcoal is pulverized in a charcoal mill and carried through an air stream to the burner in the furnace. However, in such equipment, due to a sudden load reduction, it is necessary to stop the operation of the corresponding mill in order to stop the combustion of some burners, or in extreme cases, to stop the combustion of all burners. If you simply stop supplying pulverized coal to the burner when it becomes necessary to do so (when a problem occurs), the mill will be filled with pulverized coal heated by preheated air and its combustible gas, which could cause an explosion. It had Therefore,
Conventionally, even if an immediate request to stop burner combustion as described above was issued, the mill operation could not be stopped until the inside of the mill was empty, and the burner combustion could not be stopped immediately. cannot respond to Therefore, it is necessary to adjust and control the output side to meet the above requirements.
In the event of a problem, there was a risk that the damage would be even greater because it was not possible to do so. Furthermore, even when an additional request for burner combustion is issued, the mill starts operation from empty, so it takes a long time to reach a steady state of pulverized coal supply, and it is unable to respond to sudden load requests. I had a problem.

The present invention has been made in view of these points, and includes providing a bypass flow path in a fuel pipe that leads pulverized coal from a pulverized coal device to a burner of a furnace, and guiding the pulverized coal to the bypass flow path and keeping it in a standby state. By switching the pulverized coal to the furnace side when additional combustion is required in the furnace, and switching to the bypass flow path side when rapid fire extinguishing is required, it is possible to immediately respond to requests, improve controllability, and minimize damage in the event of trouble. It was designed so that it could be stopped.

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

In the figure, (1) represents a pulverized coal equipment (referred to as a mill), which introduces coal (2), pulverizes it using a ball mill method, etc., and carries the pulverized coal into an air stream of preheated air (3). The fuel is then guided through a fuel pipe (4) to a burner (6) of a furnace (5) such as a boiler. At this time, mil (1
) are provided, for example, in a plurality so as to correspond to a plurality of burner rows. The fuel pipe (4) K and the bypass pipe (7) are connected to lead to the pulverized coal recovery device (8) having a cooling function, and the downstream position of the branch point in the fuel pipe (4) and the bypass pipe are connected. A damper (9) for each pipe (7)
(Establish 1@.

In addition, (11) in the figure shows the boiler control device, and the status of each part of the boiler, such as the generator output command a, the number of mills 03, the water supply level (14), the steam pressure 00, and the furnace pressure 010, and the auxiliary motor The operating state of 0 force θ8) is manually operated.

The boiler control device (11) instructs the damper control device (21) with a mill additional request command 09) or a rapid fire extinguishing command depending on the command and the status of each part, and the damper control device (21) that receives the command responds to the command. Based on the required mill 0) damper (9) (IQ), the damper drive device (a) which operates the on/off command @operates. The damper (9) θO is always moved in the opposite direction by the damper drive device (a). For example, the damper control device I2 is configured to be driven to open and close at the same time.
When the OFF signal is issued from 1), the damper (9) of the fuel pipe (4) opens, and the damper θO of the bypass pipe (7) closes (state shown), and conversely, when the OFF signal is issued, the damper (9) of the fuel pipe (4) opens. (9) is closed, and damper θO is opened.

In the above, under normal conditions, the number of mills (1) is driven according to the generator output command (power), and pulverized coal is supplied to the corresponding burner (0) via the fuel pipe (4) as shown in the figure. At this time, the damper (9) GJ of the fuel pipe (4) corresponding to the idle mill (1) is closed, and the damper 00 of the bypass pipe (7) is opened. If the number of generator output commands increases from this state, the required idle mills (1) are started in advance.At this time,
Since the inside of the mill (1), which has been inactive, is empty, it will take some time until the coal (2) is supplied and pulverized, and the required amount of pulverized coal is discharged. During this period, the damper (9) is closed and the damper 00) is open, so the pulverized coal is transferred to the pulverized coal recovery device (8) via the bypass pipe (7).
This keeps it in a steady state of stun.

Therefore, an additional request command is issued to the damper control device (21) from the generator output command (when ¥ increases, the boiler control device 0]), and the required mill (1)K corresponding damper drive device □□ □ is turned on, the damper (9) is opened, and the damper 00) is closed, and the pulverized coal that was flowing through the bypass pipe (7) is switched to the burner (6) side and supplied. Since it is already in a standby state, the additional burner (6) can immediately perform steady combustion to immediately respond to the command.

In addition, if the generator output command (6) suddenly decreases or stops, or if trouble occurs in the boiler's main equipment, etc., a rapid extinguishing command (e) is sent from the boiler control device 01) to the damper control device (2]). A command is issued to the damper drive device (a) corresponding to the required mill (1) to turn off the damper (9).
is closed, damper 00 is opened, and at the same time, the supply of coal (2) to the mill (1) is stopped. This immediately extinguishes the required burner (6). Also, the extinguished burner (
The mill (1) corresponding to 6) continues to send pulverized coal to the pulverized coal recovery device (8) via the bypass pipe (7) until the inside becomes empty, and when the inside becomes empty, the drive is stopped. This eliminates the danger of explosion in the mill (1), and since the pulverized coal recovery device (8) also has cooling means such as water spraying or water immersion, pulverized coal can be recovered safely. can. Moreover, this recovered pulverized coal can be used again.

As described above, according to the present invention, it is possible to immediately respond to requests for additional combustion of burner (0) and extinguishing commands, thereby improving boiler controllability and extinguishing fires when trouble occurs. By doing so immediately, you can minimize the damage.

It should be noted that the present invention is not limited only to the embodiments described above, and various changes may be made without departing from the gist of the present invention.

-J- According to the fuel control method for a pulverized coal-fired furnace of the present invention described above, the following excellent effects can be achieved.

(1) When additional combustion is requested, the mill is placed on standby using a bypass flow path, and the damper is switched to supply pulverized coal to the burner, thereby making it possible to immediately perform the requested combustion.

(11) When rapid extinguishing is requested, by switching the pulverized coal to the burner to the bypass flow path using a damper, the fire can be extinguished immediately, and the fuel in the mill after extinguishing can be discharged via the bypass flow path. This eliminates the risk of the mill exploding.

(iii) In (+) li) above, the controllability of the reboiler is improved.

(1v) Since rapid fire extinguishing becomes possible, damage when trouble occurs can be minimized.

[Brief explanation of drawings]

The drawings are explanatory diagrams showing one embodiment of the present invention. (υ is pulverized coal equipment (mill), (2) is coal, (3) is preheated air, (4) is fuel pipe, (5) is furnace, (6) is burner, (7) is bypass pipe, ( 8) is a pulverized coal recovery device, (
9) (10 is the damper, 0η is the boiler control device, (6)
denotes a generator output command, θ denotes an additional request command, (a) denotes a rapid fire extinguishing command, t21) denotes a damper control device, and (a) denotes a damper drive device.

Claims (1)

[Claims] 1) The pulverized coal fuel introduced into the furnace is bypassed and placed in a standby state, and when additional combustion in the furnace is requested, the pulverized coal is switched to the furnace side to immediately respond to the request, and when rapid extinguishing is requested, the above-mentioned A fuel control method for a pulverized coal furnace, characterized by immediately cutting off the supply of pulverized coal to the furnace by bypassing the pulverized coal.