JP2800871B2 - Incinerator combustion control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a combustion control device such as an incinerator for municipal garbage, and more particularly to an air supply means for supplying combustion air into the furnace and a supply amount of the air supply means. Air supply amount adjusting means, combustion state detecting means for detecting a combustion state of the incinerated material in the furnace, and setting a combustion state in the furnace to a target state based on a detection result of the combustion state detecting means. And a combustion control means for controlling the air supply amount adjusting means so as to maintain the adjustment.

[0002]

2. Description of the Related Art Conventionally, a combustion control apparatus for an incinerator of this type is provided with a temperature sensor for detecting a combustion temperature in the furnace as combustion state detecting means. The combustion control means controls the air supply amount adjusting means so as to adjust and maintain the combustion state of the target state,
The air supply was being adjusted.

[0003]

However, in the above-mentioned prior art, since only the temperature in the furnace is detected, the position of the temperature sensor in the furnace and the convection state of the air in the furnace are determined. Is not only difficult to accurately replace the temperature detected by the temperature sensor with the flame temperature, but also if the flame air temperature can be adjusted to the set temperature, whether the supply of combustion air is appropriate And it was difficult to properly control the combustion state. As a result, incomplete combustion may occur, and the generation of dioxin, which has a positive correlation with carbon monoxide CO, is a concern. Driving with a high excess air ratio. Therefore, the combustion efficiency was not always sufficient. The purpose of the present invention is to dedicate one measure to the measurement of the flame temperature,
Accurately grasp the combustion state of the flame, combustion efficiency, and
An object of the present invention is to provide a combustion control apparatus for an incinerator, which can perform operation while suppressing generation of carbon monoxide CO and dioxin.

[0004]

According to a feature of the present invention, the combustion state detecting means includes a burned gas contained in a flame.
Radiation temperature measuring means for measuring radiant energy in a specific wavelength range corresponding to the gas component, and unburned gas contained in the flame
A second radiation temperature measuring means for measuring radiant energy in a specific wavelength range corresponding to the component, and an excess amount of air supplied by the air supply means based on detection values of the first radiation temperature measuring means and the second radiation temperature measuring means. And a determination means for determining a shortage state. In particular, the first radiation temperature measuring means, which measures the radiant energy centered wavelength region of 4.3μm band, said second radiation temperature measuring means, a central wavelength band of 3.3μm band radiation It is preferable to configure the device to measure energy.

[0005]

In general, when the radiation energy of a black body is measured, its temperature is determined as shown in FIG. The present invention detects a flame temperature or the like by measuring radiant energy. As shown in FIG. 2, the temperature characteristic of the flame is such that when the excess air ratio = 1, the combustion temperature becomes maximum,
Shortage falls on either side. Now, paying attention to the fact that the emissivity becomes almost 1 when the thickness of the flame exceeds a certain thickness in the measurement direction of the radiation temperature measuring means, the radiation emitted by a specific burned gas component contained in this flame By measuring the energy in the first wavelength range where energy from other heat sources is removed, the combustion temperature of the flame can be known. On the other hand, the presence or absence of unburned gas components contained in the flame is measured by measuring the radiant energy in a second wavelength range different from the first wavelength range, so that the air supply amount is excessive even at the same flame temperature. It is possible to accurately determine whether the combustion state is the state or the shortage state. That is, as shown in FIG. 2, it is possible to determine which of the two points (A, B) indicating the same temperature on the characteristic curve corresponding to the combustion temperature of the flame is in the combustion state. Specifically, as shown in FIG. 5, an object to be measured by the first radiation temperature measuring means absorbs infrared rays at normal temperature, but has a flame thickness of 30 in the measurement direction.
cm or more, carbon dioxide CO ₂ , which is known to have an apparent emissivity of approximately 1 in the wavelength band of the 4.3 μm band, can be used. On the other hand, as an object to be measured by the second radiation temperature measuring means, it is possible to use hydrocarbon HC, which is an unburned gas component that emits radiant energy in a wavelength band of a 3.3 μm band.

[0006]

Therefore, since the excess air rate itself can be grasped, a combustion control device for an incinerator which can supply air properly while suppressing the generation of carbon monoxide CO or dioxin, and thus can control combustion efficiently can be provided. Can now be offered.

[0007]

Embodiments will be described below. As shown in FIG. 1, the incinerator for municipal garbage is provided with a hopper 3 for storing garbage to be incinerated, a combustion chamber 2 for incinerating the garbage, an ash pit 4 for collecting incinerated ash, and the like. It is composed. The combustion chamber 2 includes a drying zone 6 for drying dust heated by a pusher 5 provided at a lower end portion of the hopper 3 and heating the dust to near an ignition point, a combustion zone 7 for burning the dried dust, and a combustion zone 7 for the drying zone. And a post-combustion zone 8 for incineration of the refuse burned in the step is arranged stepwise from above to below, and a grate 9 arranged in an oblique vertical position is provided at the bottom of each of the hydraulic cylinders C1, C2. , C3, a stoker means 1 is provided for conveying the dust to the ash pit 4 while agitating the dust by sliding it obliquely up and down. The pusher 5 has a hydraulic cylinder C4.
The dust is extruded into the combustion chamber 2 by the reciprocating drive. The ash in the post-combustion zone 8 is used to remove ash
Ash pit 4
Is transported and accumulated. The combustion zone 7 is composed of two regions, a front combustion zone 7A and a rear combustion zone 7B. The refuse is mainly combusted in the front combustion zone 7A by a combustion control device described later, and then completely separated in the rear combustion zone 7B. It is controlled so as to burn. In the lower part of the combustion chamber 2, there is provided a supply path 17 for supplying heated air sent by a blower 16 as air supply means to the combustion chamber 2 as air for drying / combustion. The zone 7 and the post-combustion zone 8 are provided with dampers D as air flow rate adjusting means for individually adjusting the supply amount. The combustion gas generated in the combustion chamber 2 is extracted from the combustion gas by the waste heat boiler 12 in the form of steam to be used as energy of the power generator 13 and supplied to the outside of the plant. And harmful gases are removed and exhausted.

The combustion chamber 2 is provided with a temperature sensor, a gas sensor, and the like for monitoring a combustion state. More specifically, a first radiation temperature measuring means 19 and a second radiation temperature measuring means 20 as a combustion state detecting means for detecting a flame temperature of the combustion zone 7, a pressure detecting means (not shown) for detecting a furnace pressure, etc. It is. The first and second radiation temperature detecting means 19;
As shown in FIG. 1, the infrared camera 21 is integrally incorporated as an infrared camera 21. In the infrared camera 21, one infrared imaging element 22 and two filters 18A and 18A are provided.
18B. These filters 18A and 18B
It is provided at a 180 ° diagonal position of the rotating disk, and is switched to an operation state in which infrared rays are incident on the imaging element 22 for infrared rays alternately by reversing the rotating disk. One of the two filters 18A and 18B is a 4.5 μm filter that selectively passes infrared light in the first wavelength band of the 4.3 μm band and detects the temperature of carbon dioxide CO _{2 in} the flame, and the other is a filter of 3. Hydrocarbon H which is an unburned gas component in the flame by selectively passing infrared rays in the second wavelength range of the 3 μm band
This is a 3.3 μm filter that detects the presence or absence of C. The principle of measurement by such a temperature sensor is that when the flame thickness in the measurement direction is 30 cm or more, the emissivity in the 4.3 μm band carbon dioxide CO ₂ (the molar fraction of CO ₂ is 0.1 or more) wavelength region Is used to estimate the temperature of the flame by measuring the radiant energy from the 4.3 μm band carbon dioxide CO ₂ wavelength range in a high temperature range (for example, around 1000 °). It is.
Further, the radiant energy from the hydrocarbon HC wavelength range of the 3.3 μm band is measured to determine whether the excess air ratio is too small. However, since the radiant energy itself is small,
An accurate temperature state cannot be grasped, and it is determined whether or not hydrocarbon HC, which is unburned gas, exists.

The incinerator has input means 23A for inputting the values detected by the various sensors, discriminating means 23B for evaluating the combustion state of the combustion chamber 2 based on input data from the input means 23A, and discrimination results by the discriminating means 23B. In accordance with the above, the degree of opening of the damper and the like are adjusted to change the excess air ratio, the speed of introducing dust by the pusher 5, the speed of transporting the dust by the stoker means 1, and the like, and the combustion is adjusted and maintained in an appropriate combustion state. A combustion control device 23 equipped with a microcomputer having a control unit 23C is provided.

Next, the first and second radiation temperature measuring means 1
The detection values obtained by 9 and 20 and the operation of the combustion control device 23 will be described in detail with reference to FIG. (1) The temperature detected by the first radiation temperature measuring means 19 is 1
The temperature is higher than 250 ° C. and the second radiation temperature measuring means 20
When the presence of hydrocarbon HC is confirmed, it is determined that the amount of dust is large. Therefore, the amount of air for combustion is increased. Then, although not shown in FIG. 3, the combustion temperature once rises and the hydrocarbon H disappears. Then, the combustion temperature is shifted to the standard range of 1050 ° C. to 1250 ° C. by reducing the speed of introducing the refuse by the pusher 5 and, at the same time, reducing the amount of air for combustion. In the above-mentioned state, when the presence of the hydrocarbon HC is not confirmed by the second radiation temperature measuring means 20, the feeding speed of the dust by the pusher 5 is reduced, and at the same time,
Only the control to reduce the amount of air for combustion is performed, and the temperature is shifted to the standard range. (2) The temperature detected by the first radiation temperature measuring means 19 is 1
In the standard state of 050 ° C. to 1250 ° C., when the presence of hydrocarbon HC is confirmed by the second radiation temperature measuring means 20, the amount of combustion air is increased to prevent incomplete combustion. Then, the combustion temperature once rises. If the combustion temperature exceeds the standard range of 1050 ° C. to 1250 ° C., the speed of introducing garbage by the pusher 5 is reduced, and at the same time,
Reduce the amount of air for combustion. In the above state,
Hydrocarbon HC by the second radiation temperature measuring means 20
If the presence of is not confirmed, the air amount and the like are not changed so as to maintain the state. (3) The temperature detected by the first radiation temperature measuring means 19 is 1
050 ° C. or lower, the second radiation temperature measuring means 20
When the presence of hydrocarbon HC is confirmed, the amount of air for combustion is increased. The combustion temperature rises, and when the combustion temperature rises to the standard range of 1050 ° C. to 1250 ° C., the air amount and the like are not changed so as to maintain the state. If the temperature does not exceed 1050 ° C., the amount of dust and the supply of air are increased. In the above state,
Hydrocarbon HC by the second radiation temperature measuring means 20
If the presence of garbage is not confirmed, it is determined that the amount of dust is small, and the supply of the air amount is reduced. In that state,
(1) The temporary increase in the combustion temperature as described in (2) is not observed, and after a certain period of time, the speed of introducing the dust by the pusher 5 is increased, and at the same time, the amount of air for combustion is increased.

Another embodiment will be described below. (A) Another embodiment of the combustion control will be described. As shown in FIG. 6, a plurality of air outlets 25 for combustion air are formed on the left and right side walls 24, 24 extending from the combustion zone 7 to the post-combustion zone 8, and air cooling walls for cooling the side walls are provided. In things
Each of the outlets 25 is provided with an opening / closing lid 26 so that each of the outlets 25 can be freely opened and closed. Then, as shown in the figure, the outlets 25 are formed in a plurality of upper and lower stages, and, although not shown, are formed in a plurality of rows even in the direction of conveying the dust. On the other hand, the input image of the cross section of the flame by the infrared camera 21 is virtually divided into a plurality of portions as shown by a dashed line in FIG. The detection values of 19 and 20 may be output, the opening degree of the opening / closing lid 26 may be adjusted based on the detection values, and the excess air ratio may be adjusted for each divided area. As described above, instead of adopting a configuration in which the opening / closing lid 26 is provided for each of the outlets to adjust, each of the plurality of vertically-arranged outlets 25 is set as one set and arranged in the direction of transporting the dust. Each set may be provided with a combustion air amount adjustment damper to adjust the excess air ratio. (B) The elements used as the radiation temperature measuring means include:
A thermistor bolometer, a pyroelectric sensor, or the like can be used as appropriate. (C) Further, the material of the filter used for the radiation temperature measuring means is not particularly limited, and its characteristics are not limited to those described above. (D) The measurement target of the second radiation temperature measuring means 20 may be carbon monoxide CO. However, in this case, since the absorption band of carbon monoxide CO partially overlaps with the absorption band of CO ₂ , it is necessary to select carbon monoxide CO with high accuracy to be measured by the second radiation temperature measuring means 20. Requires a capable sensor function. (E) The control target for controlling the combustion state may be at least the supply amount of the combustion air amount.
It is optional to combine the input speed of the dust and the transport speed.

In the claims, reference numerals are provided for convenience of comparison with the drawings, but the present invention is not limited to the configuration shown in the attached drawings.

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram of an incinerator.

FIG. 2 is a diagram showing characteristics of a flame temperature and an excess air ratio.

FIG. 3 is a chart showing a control operation according to a combustion state.

FIG. 4 is a characteristic diagram of spectral radiation energy of a black body.

FIG. 5 is a characteristic diagram of the transmittance of the atmosphere.

FIG. 6 is a longitudinal sectional view showing a combustion air conditioning structure based on a flame temperature distribution.

[Explanation of symbols]

 Reference Signs List 16 air supply means 19 first radiation temperature measurement means 20 second radiation temperature measurement means 23B discrimination means 23C combustion control means D air supply amount adjustment means

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-61-22115 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) F23G 5/50

Claims (2)

(57) [Claims] 1. An air supply means (16) for supplying combustion air into a furnace, an air supply amount adjusting means (D) for adjusting a supply amount by the air supply means (16), and Combustion state detection means for detecting the combustion state of the incineration material; and the air supply amount adjustment means for adjusting and maintaining the combustion state in the furnace to a target state based on the detection result of the combustion state detection means. Combustion control means (23) for controlling (D)
C), wherein the combustion state detecting means is provided with a burned gas component contained in a flame.
First radiation temperature measuring means for measuring the radiant energy of a specific wavelength region corresponding to the partial (19), unburned contained in the flame
Second radiation temperature measuring means (20) for measuring radiation energy in a specific wavelength range corresponding to a gas component, and first radiation temperature measuring means (19) and second radiation temperature measuring means (20)
And a discriminating means (23B) for discriminating whether the air supply amount by the air supply means (16) is excessive or deficient based on the detected value. 2. The first radiation temperature measuring means (19),
The second radiant temperature measuring means (2) measures radiant energy having a center wavelength band of 4.3 μm band.
2. The combustion control apparatus for an incinerator according to claim 1, wherein 0) measures radiant energy having a 3.3 μm band as a central wavelength region .