JPS6349131B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a device for detecting and controlling the concentration, particle size distribution, etc. of pulverized coal supplied to a combustion device such as a boiler.

The value of coal as a fuel has increased with recent changes in the fuel situation, but in the case of large coal-fired boilers for power plants, the coal used is coal that has been pulverized to a certain particle size or less (hereinafter referred to as particle size). The pulverized coal (including extremely small pulverized coal, collectively referred to as ``pulverized coal'') is supplied to the burner and burned. Generally, pulverized coal is produced by pulverizing raw coal using a pulverizer such as a ball mill, and then pneumatically transporting it to the burner, but the concentration of pulverized coal supplied to the burner may vary depending on aging of the pulverizer, coal type, etc. and the particle size distribution is not necessarily stable.
In addition, the air flow transport pipe for pulverized coal from the pulverizer to the burner is quite curved, and since the specific gravity of the coal is greater than the specific gravity of the air, centrifugal force is applied at the bends, making it difficult to separate the coarse pulverized coal. The particle size and concentration distribution of the resulting pulverized coal differs depending on the cross section of the pipe.

For this reason, it is difficult to know the true concentration and particle size distribution of pulverized coal sent out from a pulverizer. For this reason, a portion of the pulverized coal is periodically extracted and its concentration, particle size distribution, etc. are measured (hereinafter referred to as analysis), and based on the analysis results, the classification accuracy of the pulverizer and the amount of coal fed are controlled. It is necessary to control the combustion so that it is stable. Conventionally, a sampling seat was formed in the conduit that supplied the pulverized coal to the burner, and this seat was normally closed, and the pulverized coal was opened each time for analysis to sample the pulverized coal. Specifically, the seat is first opened, then aspirate air is injected into the piping to prevent the pulverized coal from spewing out to the outside, and then a pulverized coal collection device is manually installed on the open seat. However, once the sampling was completed, the sampling device was removed, the seat was closed again, and the aspirate air was stopped, and then the collected pulverized coal was analyzed manually. For this reason, it takes a lot of effort and time to collect and analyze the pulverized coal, and since a large amount of aspirate air is injected, the concentration of the collected pulverized coal is not necessarily accurate, and the analysis accuracy is low and takes a long time. . For this reason, control of the concentration, particle size distribution, etc. of the pulverized coal supplied to the combustion device becomes delayed and inaccurate, resulting in inaccurate control of the combustion device.

This invention improves the concentration of pulverized coal supplied to a combustion device.
It is an object of the present invention to provide an apparatus capable of constantly analyzing particle size distribution without manual intervention and immediately controlling pulverized coal based on the analysis results.

In short, the present invention is characterized by comprising a measurement and analysis device that uses highly directional light such as a laser beam, and a device that controls a crusher based on the analysis results of this analysis device.

An embodiment of the present invention will be described below based on the drawings.

In Figure 1, raw coal C in the hopper is fed to coal feeder 1.
While the supply amount is adjusted by the pulverizer 3, the pulverizer is pulverized. On the other hand, heated air A for transporting and drying the pulverized coal is supplied into the pulverizer 3, and the pulverized coal is airflow transported to the classifier, where the vane 12 of the classifier applies swirling force to classify the fine granulated coal. is crushed coal supply pipe 1
3 and each pulverized coal distribution pipe 18, and is burned in a burner 14, and coarse granulated coal having a certain particle size or more is pulverized again. A pulverized coal measuring device 15 is arranged in each pulverized coal classifier 18 leading to each burner 14, and each pulverized coal measuring device 15 can transmit measurement results to each pulverized coal analyzer 16 by light intensity, electric signal, etc. is connected to. Reference numeral 17 is a control box for storing memory and issuing command signals, and is connected in circuit to the pulverized coal analyzer 16. This control box 17 further includes a coal feeder regulator 2 that adjusts the operation of the coal feeder 1, a classification performance adjusting means (vane opening degree regulator) 5 that adjusts the opening degree of the vane 12 of the classifier, and a control unit for controlling the heated air A. Each circuit is connected to a regulator 11 of a damper 10 that adjusts the inflow amount.

Regarding the particle size of pulverized coal, the amount of heated air A, the opening degree of the vane 12, and the amount of coal fed from the coal feeder are closely related to each other.

FIGS. 2 and 3 specifically show the pulverized coal measuring device. The wall surface of the pulverized coal distribution pipe 18 has small holes located at both ends of the diameter of the distribution pipe.
9 is formed, and a highly focused light R such as a laser beam is irradiated through this small hole 19. The light ray R that crossed the distribution pipe 18 passes through a convex lens 27 and mirrors 28 and 29.
The pulverized coal passes through the distribution tube 18 and reaches the pulverized coal analyzer 16, where the concentration and particle size distribution of the pulverized coal passing through the distribution pipe 18 are analyzed based on the degree of attenuation of the light beam. Since the small holes 19 formed in the distribution pipe 18 may cause the crushed coal in the distribution pipe to leak to the outside, seal air A ₁ is injected from around the small holes 19.
Since the small hole 19 of this seal air _A1 has an extremely small diameter, the amount of injection is small, so there is no concern that it will reduce the concentration of pulverized coal in the distribution pipe.

Next, the analysis results from the analyzer 16 are constantly input into the control box 17, and the control box 17 integrates these analysis results, calculates the average value, etc., and calculates the true concentration and particle size distribution of the pulverized coal sent out from the pulverizer. The pulverizer is controlled by comparing the calculated value with the control value stored in the control box. That is, in FIG. 1, when the pulverized coal concentration decreases, the control box 17 issues a command signal to the coal feeder regulator 2 to increase the amount of coal fed, and when the particle size increases, the opening degree is adjusted. A command signal is issued to the classifier 5 and the damper adjustment device 11 to adjust the opening degree of the vane 12 and increase the amount of heated air supplied to improve the classification accuracy of the classifier and reduce the particle size distribution. The control box 17 adjusts the concentration and particle size distribution of the pulverized coal supplied to the combustion device by appropriately combining the above operations.

By carrying out this invention, the properties of pulverized coal can be detected accurately at all times and without requiring manpower or time.

Furthermore, since the pulverizer can always be adjusted appropriately based on the detection results, it is possible to always stabilize the properties of the pulverized coal supplied to the combustion device.

[Brief explanation of drawings]

Fig. 1 is a system diagram of a pulverized coal analysis control device according to the present invention, Fig. 2 is a system diagram of a pulverized coal measuring device, and Fig. 3 is a system diagram of a pulverized coal measuring device.
Figure A is a sectional view of a pulverized coal distribution pipe equipped with a pulverized coal measuring device, and Figure B is a sectional view taken along line AA in Figure A. 2...Coal feeder regulator, 3...Crusher, 5...Vane opening regulator, 11...Damper regulator, 15...
... Crushed coal measuring device, 16... Crushed coal analyzing device, 1
7... Control box, 18... Crushed coal distribution pipe.

Claims (1)

[Claims] 1. A pulverized coal measuring device using a laser beam installed in each pulverized coal distribution pipe that supplies pulverized coal supplied from a coal pulverizer to each burner, and a pulverized coal analyzer that receives a signal from the measurement results. The present invention is characterized by being provided with one control box that receives a signal of the analysis result, a classification performance adjustment means controlled by a command signal from this control box, and a damper for controlling the amount of heated air supplied to the coal crusher. Pulverized coal analysis control device.