JPS59129383A - Detector for deposit in furnace - 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 an in-furnace deposit detection device for detecting the presence or absence of deposits in a combustion furnace such as a recovery boiler or an incinerator.

Knowing the presence or absence of deposits in the furnace during combustion, such as charped (solid waste liquid deposits) from the recovery boiler, ash, dust, etc., is important for efficient operation and control of the furnace.

As a method for detecting the presence or absence of such deposits in the furnace, for example, there is a method in which a window is provided in the furnace wall and monitoring is performed through the window visually or with a television camera or the like.

However, with this method, the flame (luminous flame) accompanying combustion
Since the deposits inside the furnace are blocked by the furnace, only a small part of the peripheral area near the window can be monitored, and the central part of the furnace cannot be monitored.

However, there is a conventional method of using a radiation thermometer as shown in Figure 1. In this method, a window 2 is provided on the furnace wall 1, and this window 2
A radiation thermometer 3 is disposed in the furnace, and the radiation thermometer 3 detects the thermal radiation A within the furnace, and the output voltage of the radiation thermometer 3 is monitored by an oscilloscope 4.

In this method, when the deposit 5 in the furnace is small and located at a low position, the field of view of the radiation thermometer 3 is occupied by the high-temperature flame 6, so the thermal radiation A is strong, and as a result, the output voltage of the radiation thermometer 3 is highly powerful. If the deposit 5 increases and reaches the position shown by the broken line, the deposit 5 will be visible in the field of view of the radiation thermometer 3.
' comes in. In this case, since the temperature of the deposit 5' is lower than that of the flame 6, the thermal radiation A becomes weaker, and the output voltage of the radiation thermometer 3 becomes lower.

In other words, this method detects the presence or absence of deposits 5 by detecting the thermal radiation A in the furnace coming out through the window 2 with a radiation thermometer 3 and monitoring its output voltage with an oscilloscope 4. It is something to do.

Figure 2 shows an example of the measurement results, where a shows the temporal change in the level (height) of the true deposit 5;
It shows the temporal change in the output voltage of 6Vi radiation temperature division 3. Note that since the relationship between the level and the output voltage is reversed, the axes of the output voltage are reversed.

As described above, the conventional method detects the level of the deposit 50 as temperature information from the radiation thermometer 3, but it has the following drawbacks.

(1) The intensity of the temperature of the flame 6 directly affects the output voltage of the radiation thermometer 3, so depending on the combustion state, deposits 5
The relationship between the level and the output voltage of the radiation thermometer 3 is no longer constant. That is, as shown in FIG. 2, when there is a strong flame 6, the output voltage of the radiation thermometer 3 fluctuates and does not match the level of the deposit 5.

(2) If there is a large amount of ash in the furnace other than the flame 6, the output voltage of the radiation thermometer 3 will decrease, causing the same problem as above.

The present invention has been made in view of the above-mentioned circumstances, and includes a furnace deposit detection device for detecting the presence or absence of furnace deposits during combustion. a laser beam generator that irradiates a Rede beam from one window to the other; an optical filter that is provided near the external window and transmits only light having a wavelength near the Rede beam; The object of the present invention is to include a light-receiving element that receives transmitted light from the filter, and a means for receiving the output voltage of the light-receiving element and detecting whether or not there is a predetermined amount or more of the deposits in the furnace. An object of the present invention is to provide an in-furnace deposit detection device that can accurately detect the presence or absence of in-furnace deposits without being affected by brightness or the like.

Hereinafter, one embodiment of the present invention will be described with reference to the drawings.

In FIG. 3, the furnace wall 11 is provided with a pair of windows 12a and 12b facing 7J on a straight line passing through the center of the furnace. A laser beam generator fj13 is arranged near one window 12a to radiate a laser beam from the window 12a to the other window 12bV. A narrow band optical film 14 is arranged near the external force window 12b, and is configured to transmit only light beams near the wavelength of the Rede beam. A light receiving element 15 is arranged behind the optical film 14 to receive transmitted light from the +j optical film 14 and convert it into 2.7L pressure.

The output voltage of this light receiving element 15 is monitored by an oscilloscope 16.

In this 1'r74 configuration, when detecting the presence or absence of deposits 17 in the furnace during combustion, a laser beam is made to enter the furnace from the laser beam generator 13 through the entire window 12a. The laser beam incident into the furnace passes through the optical filter 14 at the passive window 12b, and after the noise light B caused by the flame 18 is removed, it is received by the light receiving element 15. Here, when the deposit 17 is located at a position lower than the position of the laser beam, the light receiving element 15 outputs a predetermined voltage vl as shown in FIG. 4 due to the transmitted laser beam. However, if the deposit 17 increases and reaches a position higher than the position of the laser beam as shown by the broken line in FIG. 15 output voltage decreases and Vl (Vl <
Vl) Totoru. Therefore, by monitoring with an oscilloscope fl 6, it is possible to detect whether the deposit 17 is above a predetermined height.

When light enters the furnace and the transmitted light is received to detect the presence or absence of deposits, the problem arises from the noise light caused by the flame in the furnace and the signal light that passes through the furnace. This is the attenuation caused by flame and ash.

Therefore, it is desirable to use a light source with a large light output per unit area, and to select and receive only the signal light on the light receiving side.

Therefore, a laser beam generator 13 with a large output per unit area is used as a light source, and a narrow band optical filter 14 having a transmission band near the wavelength of the laser beam is used in front of the light receiving element 15. This makes it possible to most effectively detect the presence or absence of deposits 17 in the furnace.

Although it was generally unknown whether a laser beam would pass through the recovery boiler during combustion, it was confirmed through experiments that it does.

As described above, according to the present invention, a laser beam is irradiated through the furnace from a window provided on one side of the furnace wall toward the other window, and the laser beam is irradiated with an optical filter provided on the side of the other window. Since the light is received by the light-receiving element through the furnace, the present invention provides an in-furnace deposit detection device that is not affected by combustion flames in the furnace and is capable of accurately detecting the presence or absence of in-furnace deposits. can.

[Brief explanation of drawings]

Figure 1 is a configuration diagram showing a conventional in-furnace deposit detection device;
Figure 3 is a characteristic diagram showing measurement results obtained by the above method, Figure 3 is a configuration diagram showing a furnace deposit detection device according to an embodiment of the present invention, and Figure 4 is an output voltage waveform diagram of the light receiving element in the above device. be. 11... Furnace wall, 12a, 12b... Window, 13...
Laser beam generator, 14... Optical filter, 15...
・Photodetector, 16...Oscilloscope, J 7, 1
7'...Deposit, 18...Flame, B...Noise light. Applicant Sub-Agent Patent Attorney Takehiko Suzue Figure 1 Figure 2 Time Figure 3 Figure 4

Claims (1)

[Claims] In a furnace deposit detection device that detects the presence or absence of furnace deposits during combustion, a pair of windows are provided facing each other on the wall surface of the furnace, and a laser beam is emitted from the power window to the external power window. a laser beam generator that irradiates a light beam; an optical filter that is provided near the other window and that transmits only a light beam near the wavelength of the laser beam; and a light receiving element that receives the transmitted light from the optical filter; In response to the output voltage of this light receiving element,
An in-furnace deposit detection device comprising means for detecting whether or not the in-furnace deposit is present in a predetermined amount or more.