JPS58202052A - Apparatus for controlling coal feeder of fine powdery coal boiler - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a control device for a coal feeding machine that supplies coal to a pulverized coal machine (hereinafter referred to as a mill) installed in a pulverized coal-fired boiler.

A conventional coal feeder control device is shown in Fig. 1.

The actual coal feed amount signal A from the coal feed amount detector 1 is inputted to the subtractor 5 via the current/voltage converter 3, and is also input to the boiler master 2.
Similarly, the coal supply amount request signal B is inputted to the subtracter 5, where the deviation C between both signals A and B is calculated and outputted, and inputted to the proportional-integral regulator 6. The output of the regulator 6 and the output E of the differentiator 10 to which the coal feed amount request signal B is input are connected to the adder 7.
Here, both signals are added and the mill master signal F is output. The signal F is supplied to the voltage/pulse converter 8. The signal is transmitted to the coal feeder motor 11 via the pulse/pneumatic converter 9, etc., and the speed of the coal feeder is adjusted to control the amount of coal fed to the mill. In such conventional coal feeder control devices, in order to improve mill responsiveness (the time from when the amount of coal fed from the coal feeder to the mill changes until the fine powder at the mill outlet changes), , a differentiator 10 is provided, so that when the coal feeding amount request signal B changes due to adding the output from the regulator 6 and the output E from the differentiator 10, excessive (or insufficient) coal feeding is performed temporarily. I have to. (
It is well known that mill responsiveness can be improved by temporarily overcharging or undercharging. ) However, with this control method, as shown in Figure 2,
When the coal feed amount request signal B changes (increases) in steps as shown in FIG. 2 (B), the output of the regulator 6 and the output of the differentiator 10 (EVE ID), f respectively.
Changes like Fil, fFl.

Further, the actual coal supply amount signal A changes as shown in FIG. 2 tA).

In other words, even if excessive coal feeding is performed by differential operation, the actual amount of coal fed is fed back.

Since the subtractor 5 and the regulator 6 operated in reverse, the amount of coal fed was repeatedly increased and decreased as shown in Figure 2 (Al), and it could not be said that mill responsiveness was necessarily improved.

Furthermore, the stronger the differential operation and the proportional-integral operation of the regulator, the greater the amplitude of increase or decrease in the amount of coal fed, which has been an obstacle in adjusting the coal feeder control system.

The present invention has been made in view of the above points, and aims to provide a coal feeder control device that improves the responsiveness of a mill and is easy to adjust. and a subtractor that outputs the deviation between both signals, and a regulator that receives the output of the subtractor and outputs a coal feeder control signal, and controls the speed of the coal feeder based on the output of the regulator. The coal feeder control device for a pulverized coal-fired boiler is characterized in that the actual coal feed amount signal is input to the subtracter via a first-order lag characteristic device.

According to the present invention, the actual coal feed amount signal is input to the subtracter via the first-order lag characteristic device, so that when the coal feed amount request signal changes, over or under coal feed is performed, and the subtracter and proportional integral The regulator does not back-act, thus providing a coal feeder control with improved mill responsiveness.

An embodiment of the present invention will be described below with reference to FIGS. 3 and 4.

In Fig. 3, l is a coal feed amount detector, 2 is a boiler master, 3 is a current/voltage converter, 5 is a subtracter, 6 is a proportional integral regulator, 8 is a voltage/pulse converter, 9 is a pulse/air pressure The converter 11 is a coal feeder motor, which has the same functions as those with the same reference numerals in FIG.

A first-order lag characteristic device 4 has a first-order lag transfer characteristic of '1+T8, and is provided between the current/voltage converter 3 and the subtracter 5.

The actual coal feed amount signal A from the coal feed amount detector l is inputted to the first order lag characteristic device 4 via the current/voltage converter 3, and the −th order lag signal G is sent to the subtracter 5.

On the other hand, the coal feed amount request signal B from the boiler master 2 is also
The deviation H between the nine signals B and G is sent to the regulator 6. Mill master signal from controller 6! is output and sent to the coal feeder motor 11 via a voltage/pulse converter 8° pulse/air pressure converter 9, etc., and the coal feeder speed is controlled.

FIG. 4 shows an example of changes in each signal in the control system. As shown in Fig. 4 IBI, the coal feed amount request signal B changes in steps (
increase), the amount of coal fed is increased by the difference between the signal B and the actual coal feed amount signal A (=G) by the operation of the subtractor 5 and the regulator 6. However, since a first-order lag transmission element is installed in the feedback line, even if the actual coal feed amount A matches the coal feed amount request signal B, the output G of the first-order lag characteristic unit 4 will be as shown in Fig. 4 t()l. If they do not match, the amount of coal fed is increased due to the operation of the subtractor 5 and adjuster 6. As a result, the output 1 (j master signal) of the regulator 6 and the actual coal feeding amount change as shown at t11 and tAl in FIG. 4, respectively, and excessive coal feeding is performed temporarily.

On the other hand, when the output B of the boiler master 2 changes stepwise, undercharging is performed by the operation opposite to the above.

When increasing or decreasing the coal feeding amount as described above, excessive or insufficient coal feeding is carried out more reliably than in the conventional system, so that mill responsiveness is improved. Also - excess by adjusting the first-order lag time of the second-order lag characteristic.

The amount of underfeeding coal can be adjusted, and since mutual interference between the subtracter and the adjuster does not occur due to adjustment, the operation of the adjuster can be increased as much as desired, increasing the degree of freedom in adjustment.

[Brief explanation of drawings]

Figure 1 is a control system diagram showing a conventional coal feeder control device;
3 is a control system diagram showing an embodiment of the present invention, and FIG. 4 is a signal change diagram at each part of FIG. 3. i... Coal feed amount detector, 2... Boiler master, 3...
・Current/voltage converter, 4...-order lag characteristic device, 5...
- Subtractor, 6... Proportional-integral regulator, 8... Voltage/pulse converter, 9... Pulse/pneumatic pressure converter, 11...
・Coal feeder motor. A flash of hair! PJa Sendai 2nd Country 4th Citizen

Claims (1)

[Claims] A subtractor that receives a coal feeding amount request signal and an actual coal feeding amount signal and outputs a deviation between the two signals, and a regulator that receives the output of the subtracter and outputs a coal feeding machine control signal, and adjusts the same. A coal feeder control device for a pulverized coal-fired boiler that controls coal feeder speed based on a coal feeder output, characterized in that the actual coal feed amount signal is input to the subtracter via a first-order lag characteristic device. A coal feeder control device for a pulverized coal-fired boiler.