JPS60161752A - Mill controller - 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 [Field of Industrial Application] The present invention relates to a control device for a mill that supplies pulverized coal to a pulverized coal furnace.

[Prior Art] The amount of coal fed to a mill is controlled by a boiler master command according to the load of a furnace such as a boiler.

However, in the case of a vertical mill, the maximum output of the mill changes depending on the wear condition of the mill rollers, coal moisture (difference in coal type), etc. Therefore, if excessive coal is fed into the mill while the mill output is decreasing (the amount of coal that is crushed and transported to the burner is less than the amount of coal fed), coal will accumulate in the mill and resulting in outage of function. For this reason, subsequent restoration requires extremely difficult work such as having people enter the mill and scrape out the coal.

[Object of the Invention] An object of the present invention is to ensure the safety of a mill when the mill capacity is reduced due to differences in the degree of wear of the mill rollers, the coal moisture m, etc.

[Structure of the Invention] The present invention detects mill performance-lower factors such as wear of mill rollers and coal moisture content, and selects among these detection signals the one with the smallest maximum grinding capacity of the mill based on the above-mentioned factors. and a low signal selector that compares the selected low signal with a control signal based on the boiler master command and outputs a low-value signal to the coal feeder. The amount of coal fed is 1IIIll by 1t.

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

The drawing shows an example of the present invention, and the mill 1 includes a coal feeder 2.
The coal 3 is supplied by the hot air duct 4.
Primary air 8 is supplied with a flow rate controlled by an adjustment damper 6.7 provided in the cold air duct 5.

Further, the control of the amount of coal feeding and the amount of primary air is generally performed by comparing the boiler master command 9 and the signal 11 from the rotation speed detector 10 of the coal feeding @ 2 using a draw rod 12 to determine the difference. The coal feeder 2 is controlled by the control signal 13 through the I moderator 14.
This is done by controlling the rotational speed of the damper 6.7 and controlling each damper 6.7 via the damper adjustment device 15.

In the above configuration, a low signal selector 1G is provided in the middle of the circuit for the control signal 13, and another low signal selector 11 is further connected to it. Further, the low signal selector 17 is inputted with the roller wear degree signal 19 from the roller wear degree detection device H1g of the mill via a function generator 20, and the detected coal water content signal 21 is inputted with a function generator. 22, and other factors are input as signals 23.

Further, the roller wear degree detection device @18 controls, for example, increasing the mill load and air flow rate at a required rate of change, and at the same time detects the mill load and the mill differential pressure, and determines the relationship between the mill load and the mill differential pressure. The degree of wear of the roller is detected by comparing it with the case of a new roller, which has been measured in advance. 24 indicates a selection signal, and 25 indicates a command signal.

With the above configuration, first, in the low signal selector 17, the roller wear degree signal 19, the moisture m signal 21, and the other factor signal 23 are selected.
Among them, the signal with the lowest maximum crushing capacity of the mill 1 is selected as the selection signal 24, and the signal @ 24 and the control signal 13 are further compared by the low signal generator 16, and the lower one is selected. The coal feeder 2 and the adjustment damper 6.1 are controlled using the signal as the command signal 25. Thereby, it is possible to automatically adjust the coal supply amount commensurate with the decrease in the capacity of the mill 1, and prevent coal from being abnormally stored in the mill 1.

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

[Effects of the Invention] As described above, according to the mill control device of the present invention, the amount of coal fed can be controlled by the signal that has the lowest maximum grinding capacity due to factors that reduce mill capacity such as mill roller wear and coal moisture. As a result, the amount of coal supplied can be automatically adjusted to match the decrease in mill capacity, thereby preventing situations where coal accumulates abnormally in the mill and the mill stops functioning. It can produce excellent effects.

[Brief explanation of drawings]

The drawings are explanatory diagrams showing one embodiment of the present invention. 1 is a mill, 2 is a coal feeder, 6 and 7 are adjusting dampers, 9 is a boiler master command, 13 is a control signal, 16.17 is a low signal selector, 18 is a roller wear degree detection device, 19 is a roller wear degree signal , 21 is a moisture m signal, 24 is a selection signal, and 25 is a command signal. Patent application Hitoshi Kawajimabari Heavy Industries Co., Ltd.

Claims (1)

[Claims] 1) Input signals based on factors such as the degree of wear of the mill rollers and the moisture content of the coal, which are factors that reduce the performance of the mill, and select the one with the smallest maximum crushing capacity of the mill based on the factors mentioned above. The present invention is equipped with a low signal selector that outputs a selection signal, and a low signal selector that compares the selection signal with a control signal based on a boiler master command and outputs a low value signal for coal feeding. Characteristic mill control device.