JP2001033018A - Method and apparatus for controlling combustion of burning furnace - Google Patents

Abstract

PROBLEM TO BE SOLVED: To maintain a predetermined or higher temperature and to stabilize an exhaust gas concentration to a lowest limit by irradiating a plurality of directions of a combustion area in a furnace with a light having a specific wavelength, obtaining a sectional distribution of a gas concentration or temperature of the area, and controlling an air amount to be supplied to the area based on the distribution of its measured result. SOLUTION: A refuse incinerating furnace 1 burns and gasifies a refuse supplied from a hopper 2 in a stoker 3 by a primary air supplied from below. A combustion gas gasified by a primary combustion unit 11 is sent to a secondary combustion unit 12, and completely burned by a secondary air. In the combustion state, gas temperature and concentration in the furnace are calculated by a signal processor 37 based on detection signals from a laser oscillator and a laser photodetector, and signals based on the calculated results are sent to a controller 28 in real time and controlled. This measuring method measures and calculates a sectional distribution state accurately in real time at each of four combustion control sections in the furnace by disposing a suitable number of measuring ends of a gas temperature and concentration measuring unit to obtain a plurality of detected results.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a combustion control method for various combustion furnaces including a boiler, a stoker furnace, and a fluidized-bed furnace for burning combustion products having a variation in supplied heat energy, and a control apparatus therefor.

[0002]

2. Description of the Related Art In the case of burning incinerators such as municipal solid waste incinerators, which are difficult to supply quantitatively and whose supply heat energy such as fuel properties varies, the fuel is supplied. Gas concentration and combustion temperature change due to changes in the amount / quality and the amount of combustion air. The change in the gas concentration or the combustion temperature leads to an increase in the concentration of carbon monoxide and nitrogen oxides, and further, to the generation of dioxin. For this reason, conventionally, various combustion control devices for refuse incinerators with large fluctuations in the supply amount / quality of the fuel have been proposed.

FIG. 7 is a control block diagram of a stoker furnace applied to a conventional refuse incinerator. In the figure, reference numeral 1 denotes a stoker furnace as a refuse incinerator, and a stoker 3 for depositing a refuse layer is disposed at the bottom. An ash chute 14 that conveys the ash after burning the combustion material to a predetermined position is disposed downstream of the refuse layer.

[0004] A combustion material supply hopper 2 is provided upstream of the stoker 3 for supplying a combustion material such as municipal waste to the stoker 3. A feeder 17 is provided below the hopper 2 to be driven by hydraulic pressure and to extrude the combusted material to the dust layer 15 on the stoker 3. The combustion material sent by the feeder 17 is gasified and primary-combusted in the refuse layer 15 by the primary air whose flow rate is controlled by the primary air supply valve 7 below the stoker 3 while moving on the stoker 3, and the primary combustion chamber The fuel is completely burned in the secondary combustion part 12 at the upper part of the fuel cell 11. A secondary air supply port 18 is provided at an inlet of the secondary combustion unit 12,
With the secondary air whose flow rate is controlled by the secondary air supply valve 8, complete combustion of the pyrolysis gas gasified in the primary combustion chamber 11 is achieved.

Reference numeral 28 denotes a control device, which includes a thermocouple 109 installed on a furnace wall, a suction pyrometer 110, a furnace top camera 112 at an upper part of the furnace, an infrared camera 113 installed at a furnace outlet,
Gas concentration meter 111 installed at the furnace outlet or further behind,
The opening / closing control of the secondary air supply valve 8 is performed based on the detection signal from the above.

[0006]

However, according to such prior art, there are the following problems, respectively. (1) Issues in determining the combustion state from temperature measurement a. Although there is temperature measurement by the thermocouple 109 installed on the furnace wall, the response is poor and the time delay is large. In addition, it only measures the temperature near the furnace wall, and cannot measure the temperature at the center of the furnace, making it difficult to accurately grasp the combustion state. B. Also, there is a device such as a suction pyrometer 110 that measures the temperature by sucking gas from the furnace, but the response is poor, and the temperature cannot be measured at the center of the furnace. It is difficult to grasp the state. C. There is also a method of installing an infrared camera 113 at the furnace outlet to measure the temperature, but it is outside the furnace and measures only the time delay and the maximum temperature. Therefore, none of these temperature measurements can know the combustion state in the furnace in real time and the temperature at the center of the furnace.

(2) Problems in the method of judging the combustion state based on the generation amount of harmful gas Further, the exhaust gas concentration is measured using a gas concentration meter 111 at the furnace outlet or further at the rear, and the combustion state is determined by increasing or decreasing the generation amount. There was a way to judge, but it did not solve the problem of time delay.

(3) Problems in Method of Determining Combustion State from Camera Image There is a method of installing a furnace top camera 112 at the upper part of the furnace and judging the combustion state based on the brightness and color of the image. There is a problem that combustion cannot be distinguished.

(4) Problems in the method of grasping the combustion state by the fluctuation of the steam amount Since the combustion control is performed as the stable combustion in which the fluctuation of the steam amount in the boiler is small, the concept that the fluctuation of the steam amount coincides with the combustion state. However, the time delay is still large.

Therefore, in each of the conventional control methods described above, the combustion state is estimated based on the detection signal, and the secondary air supply valve 8 and the primary air, which are the operation terminals, are operated by various methods (PI control, fuzzy control, etc.). Although the combustion control is performed by operating the supply valve 7 alone or both, it is not possible to follow a rapid change in the combustion state.

However, recently, the necessity of real-time combustion control according to the combustion state has been increasing due to stricter exhaust gas regulations and dioxin control, and it is necessary and indispensable to improve the combustion control using conventional measuring means. And an early solution is desired.

However, as described above, in the refuse incinerator, the fuel is refuse, and its calorific value and component are undefined. After combustion, its calorific value and the component and concentration of exhaust gas are determined, and The fluctuation is more remarkable than other furnaces. For this reason, it is desirable to directly measure the combustion field and reflect the result in the control. However, there has been no measurement means for performing the measurement under adverse conditions such as high temperature and corrosive gas in the furnace atmosphere.

In view of the above problems, the present invention provides a combustion furnace combustion control method and a combustion furnace control method capable of quantitatively and accurately grasping the unevenness of combustion based on the gas temperature and various gas concentrations in the combustion furnace. It is intended to provide a device.
Another object of the present invention is to precisely and promptly eliminate combustion unevenness in the furnace, maintain a stable combustion state, maintain a uniform high temperature by maintaining uniformity in the combustion furnace, and reduce the exhaust gas concentration. It is an object of the present invention to provide a combustion control method and a control device for a combustion furnace that can be stabilized to a minimum.

[0014]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention relates to a combustion control method for a combustion furnace including a boiler, a stoker furnace, and a fluidized-bed furnace for burning a combustion material having a variation in thermal energy. A specific wavelength light is irradiated in a plurality of directions of the in-furnace combustion region to determine a gas concentration or gas temperature cross-sectional distribution in the combustion region, and is supplied to at least the combustion region based on the gas concentration or gas temperature cross-sectional distribution. The present invention proposes a combustion control method for a combustion furnace, characterized in that the air amount is controlled.

Here, the specific wavelength light refers to a laser light such as a pulse laser, and the gas concentration or the gas temperature can be measured by the wavelength of the laser light and the intensity of the received light. By using a laser having a wavelength corresponding to the absorption wavelength of the gas to be obtained, the gas concentration or the gas temperature can be measured based on the laser spectral absorption method as described in claim 4, and the laser radar The two lasers having the resonance wavelength and the non-resonance wavelength of the corresponding gas are oscillated / received, and the gas concentration can be obtained by the difference absorption method based on the difference between the received light intensities.

By rotating the laser radar not only in the horizontal direction but also in the vertical direction in the three axes of XYZ, it is possible to measure the three-dimensional distribution of the entire furnace. As a result, it became possible to quantitatively grasp the combustion state in the furnace corresponding to the gas temperature and various gas concentrations in the combustion furnace as uneven combustion.

In the gas concentration of the laser spectroscopic absorption method, the absorption amount changes with the temperature change, but O ₂ and H ₂ O are present. Regarding the measurement, by calculating the gas temperature from the ratio of the absorption amounts of two adjacent wavelengths in the detection wavelength band of the specific gas type,
When measuring including the temperature of the flame, like H ₂ O,
When measuring the gas temperature using the gas present in the flame, and when measuring the temperature without including the temperature of the flame, measure the gas temperature using a gas such as O ₂ that hardly exists in the flame. By combining the two temperature measurements of the points to be performed, it is possible to accurately measure the temperature by removing the noise temperature due to the flame, and it is also possible to determine the amount of the pyrolysis gas supplied to the secondary combustion part, and the like. For example, the opening and closing control of each of the secondary air supply valve and the primary air supply valve can be accurately performed.

In order to control combustion, CO, NOx,
The concentration of a gas such as HCl, O ₂ , H ₂ O contained in a furnace and controlled is measured.

In this case, preferably, the combustion zone is divided into a plurality of combustion control zones, and the supply air amount is controlled for each of the plurality of combustion control zones. More specifically, as described in claim 3, the specific wavelength light calculates a plurality of detection signals obtained by sandwiching one or a plurality of combustion control regions, and determines a gas concentration or a gas concentration in a corresponding combustion control region. It is better to determine the gas temperature.

Thus, the present invention divides the inside of the furnace into a plurality of combustion control sections, and opens and closes, for example, the secondary air supply valve and the primary air supply valve as operating ends which can be individually controlled. By controlling, based on quantitative distribution measurement, by controlling the operating end of the corresponding combustion zone, a stable combustion state without combustion unevenness is maintained,
By maintaining a uniform high temperature inside the combustion furnace,
It is possible to stabilize the exhaust gas concentration to the minimum.

According to a sixth aspect of the present invention, an optical fiber is used for a laser oscillation section or a laser receiving section.

Thus, since the laser oscillating unit or the laser receiving unit can be separated from the furnace, there is an advantage that handling of the laser oscillating unit or the laser receiving unit such as measures against temperature and vibration becomes easy. Furthermore, with optical fiber,
The oscillation unit or the light receiving unit can be branched, so that the cost of the device can be reduced and the intensity of the laser beam can be made uniform when a plurality of devices are used.

According to a seventh aspect of the present invention, there is provided an apparatus for effectively carrying out the above-mentioned invention, wherein a secondary combustion section is provided above the primary combustion section, and each of the combustion sections has primary air and secondary air. In a combustion control apparatus of a waste combustion furnace for performing combustion control by supplying air, one or more laser oscillation / reception means for irradiating light of a specific wavelength in a plurality of directions of a combustion area in the furnace, and detection by the reception means Means for calculating a cross section of the gas concentration or gas temperature of the corresponding combustion control area by a signal; and, based on the gas concentration or gas temperature obtained by the calculation means, at least primary air or secondary air supplied to the corresponding combustion control area. It is characterized in that the amount of secondary air is controlled.

And, as shown in the invention of claim 8,
The combustion area is divided into a plurality of combustion control areas, and an air amount supply means for each of the plurality of combustion control areas and a control means for performing supply control of each air amount supply means based on the gas concentration or the gas temperature. With this arrangement, the invention described in claim 2 can be effectively achieved.

Further, according to the ninth aspect of the present invention, the optical path length of the specific wavelength light from the laser oscillation means to the reception means is set so as to pass through one or a plurality of combustion control areas, and the transmitted light The invention according to claim 3 can be effectively achieved by calculating a plurality of detection signals obtained by receiving the above and calculating the gas concentration or the gas temperature in the corresponding combustion control region.

In a combustion control apparatus in which the measurement of the gas concentration or the gas temperature is performed by a laser spectral absorption method, the laser light oscillated by the laser oscillation section is a gas light. A plurality of types of laser light for controlling two adjacent absorption wavelengths and combustion control of the gas type for measuring the temperature.

In the eleventh aspect of the present invention, the laser light oscillated from the laser oscillating unit is a plurality of types of laser light having a resonance wavelength and a non-resonance wavelength of a corresponding gas. Further, in the invention according to claim 12,
An optical fiber is used for a laser oscillation section or a laser receiving section.

[0028]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to an embodiment shown in the drawings. However, the dimensions, materials, shapes, relative arrangements, and the like of the components described in this embodiment are not merely intended to limit the scope of the present invention, but are merely illustrative examples unless otherwise specified. Absent. still,
In each of the embodiments described below, the number of measurement points and the number of planes of distribution measurement are specified as the minimum number of units for the combustion furnace, the number of measurement points, and the number of divisions of the combustion control area in order to make the description easy to understand. Not something.

[First Embodiment] FIG. 1 is an overall configuration diagram of an embodiment in which the present invention is applied to a stoker furnace in order to explain a whole refuse incinerator and a control device, and FIG. In the A sectional view, the same functional components in FIG. 7 are denoted by the same reference numerals, and detailed description thereof is omitted.

In the present embodiment, as in the prior art, the refuse incinerator 1 gasifies the refuse supplied from the hopper 2 on the stoker 3 by the primary air supplied from below. As the control means on the primary air side, the supply amount of dust from the hopper 2 and the feeder 17 is increased / decreased, the feed speed of the stoker 3 is changed, and the primary air supply valve 7 supplies the primary air from the lower portion of the stoker 3 at each operation end. There are changes. Next, the combustion gas gasified in the primary combustion unit 11 is sent into the secondary combustion unit 12, where complete combustion is performed by the secondary air.

The secondary combustion section 12 is set so that the secondary air supply amount can be changed for each secondary air operation end 18 (secondary air supply section) by the secondary air supply valve 8. 2
As shown in the figure, a plurality of secondary air supply units 18 in the furnace are provided at positions facing the L-shaped frames 19A to 19D at each corner so as to divide the inside of the rectangular furnace into approximately four combustion control zones A to D. Supply ports 18A to 18D are provided respectively, and the combustion control area is divided into four in the vertical and horizontal directions in the present embodiment. The laser oscillating units 24a to 24d and the laser receiving unit 25a are positioned between the L-shaped frames 19 in which the plurality of supply ports are provided.
To 25d are arranged respectively.

The laser oscillators 24a... And the laser receiver 25
a ... are four pairs of laser oscillating parts 24a to 24d and laser light receiving parts 25a to 25d symmetrically arranged between opposite sides so that laser light is transmitted in parallel with each side, and further in a direction parallel to the diagonal line. A laser oscillating unit 24e and a laser light receiving unit 2 disposed at corresponding positions on adjacent sides so that laser light is transmitted;
5e. The respective light receiving sections 24a ...
After the detected signals are calculated by the signal processing unit to the corresponding gas concentration and gas temperature, an operation signal based on the gas concentration and gas temperature is sent to the control device 28, and the following combustion control is performed. It is.

That is, the combustion state of the refuse is calculated based on the detection signals from the laser oscillating sections 24a and the laser receiving sections 25a and the gas temperature and gas concentration inside the furnace are calculated in a signal processing section 37, and the calculation is performed. An operation signal based on the result is sent to the control device 28 in real time.

In this measuring method, as shown in FIG. 2, the number of measuring ends 24a to 25e of the gas temperature / concentration measuring device is appropriately set so that a plurality of detection results are obtained in almost every four combustion control zones A to D. By doing so, it is possible to accurately and in real time measure and calculate the cross-sectional distribution state for each of approximately four combustion control zones A to D inside the furnace.

For example, in the control area A, the detection signals from the light receiving sections 25a and 25b received from the position displaced by 90 ° are used. In the control area B, the light receiving sections 25b and 2b are received.
In the control area C, the detection signal from the light receiving section 25
c and the detection signal from the light receiving unit 25d as input signals, respectively, and in addition to the light receiving unit 25d and the light receiving unit 25a received from the position displaced by 90 ° in the control area D, the detection signal from the position displaced 45 ° in the diagonal direction is added. Three signals of the light receiving section 25e of the diagonal signal are set as input signals.

The control device 28 calculates the distribution of gas temperature and concentration in each control area by the signal processing section 37 from the respective detection signals, and for each of the control areas A to D based on the calculation result. The combustion state is controlled by operating the primary air supply valve 7 or the secondary air supply valve 8 alone or both so that the distribution state of the gas temperature and concentration becomes uniform. The laser receiving sections 25a are not installed only on the opposite side of the laser oscillation sections 24a as shown in FIG. 1 or FIG. It is possible to increase the input signal and the detection area in each of the control areas A to D.

Next, the principle of measuring the gas temperature and concentration by the laser light will be described. Laser oscillation part 24a ...
Since the laser light irradiated into the furnace has a specific wavelength, the gas temperature and concentration can be measured by its spectral and absorption functions. That is, the stoker-type refuse combustion furnace of the present embodiment is:
The furnace temperature, particularly the temperature of the secondary combustion section 12, is 800 to 120.
Since the temperature is as high as 0 ° C. and the furnace cross-sectional area is large, as described above, the means for measuring up to now has been limited, and the measurement content has been limited only to the side of a wall, and a time delay has occurred. On the other hand, in the case of laser light, the inside of the high-temperature furnace is included in real time and including the furnace center by arranging the semiconductor laser oscillating portions 24a and the light receiving portions 25a diagonally between two facing sides or between two adjacent sides. Measurement at any position is possible.

The principle of temperature measurement using laser light is as follows.
For example, a specific gas existing in a furnace such as O ₂ or H ₂ O is measured, and a temperature at which a theoretical absorption line shape that best matches the absorption line shape obtained by the measurement is given as a measurement temperature,
Although a detailed description thereof is omitted because it is publicly known, a HITRAN spectrum database was used for calculating the theoretical shape of the absorption line.

According to this embodiment, when measuring the gas temperature in the combustion furnace 1, if a flame exists on the laser optical axis,
Since using O ₂ absent O ₂ in the flame in the temperature measurement, it is possible to measure the gas temperature, except for the flame temperature. On the other hand, when the temperature is measured using a gas such as H ₂ O present in the flame, the gas temperature can be measured in consideration of the flame temperature.

Next, the principle of gas concentration measurement using laser light is that the measured value of the peak of the absorption line for a specific gas is converted from the above-mentioned furnace temperature from the HITRAN spectrum database, and this value is converted to the gas concentration. Concentration. The gas concentration can be measured at a high temperature (800 to 1200 ° C.).

Accordingly, the gas temperature or the various gas concentrations in each combustion control zone and the distribution state thereof are measured by the input signal of the laser beam, and these are individually or combined as control parameters to be used as primary parameters at the operating end. By controlling the air supply valve 7 or the secondary air supply valve 8 individually or in combination, the improvement of the combustion state and the stable combustion are controlled. At this time, an optimal control method such as well-known PID control and fuzzy control is used.

For example, according to the above-mentioned measuring method, the temperature measured by using the temperature of O ₂ not present in the flame, the temperature measured by using the gas present in the flame such as H ₂ O,
Four control parameters of the _two concentrations and the CO ₂ , NOx, and H ₂ O concentrations are obtained, and control parameters of the secondary combustion unit 12 and the primary combustion unit 11 are obtained based on the four parameters.

However, the pair of laser oscillators 24a
... / light receiving unit 25a can measure only the average gas temperature and concentration of one optical axis in the furnace, and when the combustion unevenness occurs in the furnace like a garbage incinerator, the combustion state is unstable. This can have a significant effect on the fluctuations in the exhaust gas concentration. In order to be able to cope with such combustion unevenness, the control is divided into a plurality of combustion control areas A to D.

That is, as shown in FIG. 2, a plurality of detection results are output from the measurement end of the laser oscillation section 24 / light receiving section 25 for measuring the gas temperature and concentration in each of approximately four combustion control zones A to D. By appropriately setting the number, it is possible to accurately measure the distribution state of the cross section in each of approximately four combustion control zones A to D inside the furnace. FIG. 2 illustrates five sets of gas temperature and concentration measuring devices for illustration.
The mounting method, the number of installations, the number of measurement cross sections, and the like are not particularly limited.

In addition, since the number of installations is directly reflected in the cost, it is possible to use an optical fiber to distribute the light from one laser light source to a plurality of sets of laser oscillation units. Utilizing the method described above, it is possible to obtain advantages such as separating the laser light source from an adverse environment such as heat and vibration, and further eliminating variations in the amount of light. Also, an optical fiber can be used for the laser receiving section.

As described above, in the present embodiment, the combustion furnace is divided into a plurality of combustion control zones A to D, and the distribution of gas temperature and various gas concentrations is quantitatively grasped, whereby each combustion control is performed. The combustion state in the sections A to D can be quantitatively and accurately grasped as the combustion unevenness, and precise combustion control can be performed.

That is, in order to eliminate combustion unevenness, the inside of the furnace is divided into a plurality of sections A to D, and the secondary air supply valve 8 and the primary air supply valve 7 are individually provided as operating ends capable of changing the respective combustion states. To set and arrange the operation control sections as controllable operation ends by dividing them into the combustion control areas A to D, and to detect the combustion unevenness based on the quantitative distribution measurement and to control the corresponding operation end as described above. Accordingly, it is possible to maintain a stable combustion state with no combustion unevenness, maintain a uniform high temperature by maintaining uniformity in the combustion furnace 1, and stabilize the exhaust gas concentration to a minimum.

[Second Embodiment] FIG.
FIG. 6 is a configuration diagram according to a second embodiment of the present invention in a case where measurement ends of a... / light receiving units 25a. In the present embodiment, the gas temperature
The concentration measuring device, that is, the laser oscillating unit 24a and the laser receiving unit 25a are arranged not in the same plane but in a plurality of upper and lower cross sections as described above. Are more three-dimensionally determined than in the first embodiment.

The control device 28 changes the control parameters for opening and closing the secondary air supply valve 8 and the primary air supply valve 7 from the three-dimensional distribution state of the gas temperature and concentration calculated by the signal processing section 37. Primary air supply valve 7 or secondary air supply valve 8 so that the distribution of gas temperature and concentration becomes uniform.
Can be operated alone or both to control the combustion state.

The multiple stages may be installed vertically in the secondary combustion section 12, or the primary combustion section 11 and the secondary combustion section 1
Two of them may be arranged vertically. Laser oscillation section 24a
… And the laser receiving unit 25a…
Since this is the same as the first embodiment shown in FIG. 1, detailed description of this embodiment will be omitted.

According to the present embodiment, by performing distribution measurement of a plurality of cross sections, it is possible to know the distribution of gas temperature and concentration that is more three-dimensional and closer to the state in the furnace than in the first embodiment. It becomes possible.

Third Embodiment FIGS. 4 and 5 show another embodiment in which a laser radar is installed in a refuse incinerator, FIG. 4 is an overall configuration diagram, and FIG. 5 is BB of FIG. It is sectional drawing. The laser radar (oscillating unit) 30 and (light receiving unit) 4
0, as shown in FIG. 6, a short pulse laser having a time width of about 10 ns from the pulse laser oscillating unit 30 through the optical system 32 to generate rearward scattered light reflected by the measurement target gas, water vapor, or dust in the furnace. Focusing on the focusing telescope 33,
The condensed confusion light is detected by the photodetector 36 via the optical system 34 and the filter 35.

At this time, a plurality of oscillation wavelengths from the pulse laser are set, and a plurality of wavelengths are set to resonate with the absorption wavelength of the monitored gas in the furnace 1 and a plurality of wavelengths in the case of non-resonance. Then, the photodetector 36 detects the confounding light at the wavelengths of both the plurality of resonance wavelengths and the non-resonance wavelengths, and sends the detection signal to the signal processing / display unit 37. The signal processing unit 37 can derive the gas concentration at each confusion position from the difference in the decay state of the detection signal at each time. Further, since the gas concentration distribution waveform varies depending on the temperature, the temperature can be measured by detecting the wave height of the concentration distribution waveform as described above.

More specifically, the laser beam emitted from the laser oscillating unit 30 into the furnace is scattered by various particles 42 existing in the furnace, such as gas molecules, moisture, and dust. , Are absorbed by the particles 42.
Since the wavelength of the absorbed light is determined by the type of the particle 42, when a laser having a wavelength that resonates with the molecule to be monitored is irradiated, compared with the case of non-resonance, the absorption by the molecule as it propagates in the furnace is performed. , Its strength becomes weaker. Therefore, the attenuation of the light detected by the backscattering by the photodetector 36 is larger in the case of the laser in the resonance state.

Therefore, by selecting and using a wavelength that resonates with O ₂ molecules that do not exist in the flame and a wavelength that resonates with gas molecules such as CO and H ₂ O that exist in the flame, O _{2 is obtained.}
As described above, the control parameters of the concentration and the CO and H ₂ O concentrations are obtained, and the control parameters of the secondary combustion unit 12 and the primary combustion unit 11 are obtained based on the parameters.

The intensity of scattered light from a position separated by a distance R from the pulse laser light source (oscillator) 30 and the photodetector 36 is given by the following laser radar equation (1). P (R) = {P ₀ lK} ⁿ (R) β (R) A _r Y (R)} / R ² (1) where P ₀ : pulse light output (W), τ: pulse time width Yes, P ₀ τ becomes the pulse output (J). l = cτ / 2; half of the laser pulse space length (m) c; speed of light (m / s) K; total efficiency of transmitting / receiving optical system (−) T (R); transmittance of corresponding gas particles (−) Β (R); volume backscattering coefficient of the scatterer (sr ^-1 · m ^-1 ) _Ar ; opening area of the receiving optical system (m ² ) Y (R); parameter indicating the overlap between the transmitted light and the received field of view (1 when laser and receiving light are coaxial)

In the equation (1), the terms other than the transmittance T (R) of the corresponding gas particles have substantially the same resonant and non-resonant laser light wavelengths, and can be regarded as being equal with a very good approximation. Accordingly, the concentration of the corresponding gas particles is determined from the two laser light wavelengths of resonance and non-resonance, and the concentration of the gas particles corresponds to the transmittance T (R) of the gas particles. By doing so, “l = cτ / 2; half (m) of the laser pulse space length”, in other words, the distance to the measurement particle is obtained.

Therefore, in the present embodiment, a laser radar oscillating unit 30 for oscillating a short pulse laser and a laser radar receiver 40 including a converging telescope and the like are prepared.
By changing the laser oscillation direction, the distribution state of the cross section of each of the plurality of combustion control sections inside the furnace can be measured with high accuracy.

Therefore, according to the present embodiment, the combustion state of the refuse is determined by the gas concentration measurement device installed in the upper part of the furnace, even if one set of laser radars 30 and 40 is used. Is measured, and the result is sent to the control device 28 via the signal processing / display device 37 in real time.

That is, as shown in FIG. 5, a plurality of resonance wavelengths and non-resonance wavelengths are paired by a oscillating unit 30 of a laser radar connected to a turning means 41 for turning left and right and up and down in a predetermined direction in the furnace. Is scattered and absorbed by particles 42 such as oxygen gas molecules and water vapor in the furnace. Since the laser light having a wavelength that resonates with the molecule to be monitored has a larger attenuation of the light detected by the photodetector 36 than the non-resonant laser, the laser light has a certain distance in each combustion control area in the furnace. Will be measured.

From this, the gas concentration distribution at an arbitrary point on the laser optical axis is measured by the signal processing / display unit 37.
Further, by measuring the gas concentration distribution on the laser optical axis in many directions while rotating the laser optical axis right and left on the plane by the swirling means 41, it is possible to measure the gas concentration distribution of one section in the furnace. The three-dimensional distribution of the gas concentration can be measured by adding the turning direction and the vertical direction of the turning means 41.

Therefore, according to the present embodiment, the distribution state of the cross section inside the furnace can be measured by installing the pair of laser radars 30, 40 so that the optical axis is movable by the turning means 41 or the like. In the control device 28, the signal processing unit 37
The primary air supply valve 7 or the secondary air supply valve 8 is used alone or both so that the parameters of the control means are changed from the gas concentration distribution obtained from the side so that the gas concentration distribution is uniform. Operation can control the combustion state.

[0063]

As described above, according to the present invention, the combustion state in the furnace can be quantitatively grasped as combustion unevenness based on the distribution state of the gas temperature and various gas concentrations in the combustion furnace. At the same time, in order to eliminate the combustion unevenness, the inside of the furnace is divided into a plurality of combustion control areas, and an operation end capable of individually controlling each combustion area is arranged, and a quantitative distribution obtained from the measurement results is obtained. By controlling the corresponding operating end based on the measurement, a stable combustion state without combustion unevenness is maintained, and the uniformity inside the combustion furnace maintains a high temperature above a certain level, and the exhaust gas concentration is stabilized to the minimum. It is possible to do.

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram of an embodiment in which the present invention is applied to a stoker furnace in order to explain a refuse incinerator and an entire control device.

FIG. 2 is a sectional view taken along line AA of FIG.

FIG. 3 is a configuration diagram according to a second embodiment of the present invention in a case where measurement ends of a laser oscillation unit / light receiving unit are installed in a plurality of sections of a refuse incinerator.

4 and 5 show another embodiment in which a laser radar is installed in a refuse incinerator, FIG. 4 is an overall configuration diagram, and FIG. 5 is a diagram of a combustion control device according to a second embodiment. It is a block diagram.

FIG. 5 is a sectional view taken along line BB of FIG. 4;

FIG. 6 is a principle diagram showing a gas concentration analyzer when a laser having a resonance wavelength and a laser having a non-resonance wavelength are irradiated.

Fig. 7 Measurement of combustion state in conventional waste incinerator
FIG. 2 is a configuration diagram of a control unit, and is an overall configuration diagram corresponding to FIG. 1.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Garbage incinerator 2 Hopper 3 Stalker 7 Primary air supply valve 8 Secondary air supply valve 11 Primary combustion part 12 Secondary combustion part 14 Ash chute 15 Garbage layer 17 Feeder 24 Laser oscillation part 25 Laser light receiving part 28 Controller 30,40 Laser radar 36 Photodetector 37 Signal processing / display device 41 Rotating means 42 Particle 109 Thermocouple 110 Suction pyrometer 111 Gas concentration meter 112 Out-of-pile camera 113 Infrared camera

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Tominaga Kokubo 12 Nishikicho, Naka-ku, Yokohama-shi F-term in Mitsubishi Heavy Industries, Ltd. Yokohama Works 3K062 AA01 AA11 AA23 AB01 AC01 BA02 CA06 DA03 DA22 DA23 DA25 DA27 DB08 DB09

Claims (12)

[Claims] In a combustion control method for a combustion furnace including a boiler, a stoker furnace, and a fluidized-bed furnace for burning a combustion material having a variation in supplied heat energy, a specific wavelength light is irradiated to a plurality of directions of a combustion zone in the furnace. A gas distribution or a gas temperature cross-sectional distribution in the combustion zone, and controlling at least an amount of air supplied to the combustion zone based on the gas concentration or the gas temperature cross-sectional distribution. Combustion control method. 2. The combustion control method for a combustion furnace according to claim 1, wherein the combustion zone is divided into a plurality of combustion control zones, and the amount of supplied air is controlled for each of the plurality of combustion control zones. 3. The method according to claim 1, wherein the specific wavelength light calculates a plurality of detection signals obtained by sandwiching one or a plurality of combustion control regions, and instantaneously obtains a gas concentration or a gas temperature of a corresponding combustion control region. The combustion control method for a combustion furnace according to claim 1, wherein: 4. The combustion according to claim 1, wherein the measurement of the gas concentration or the gas temperature is obtained by a laser spectral absorption method or a difference absorption method based on a difference between a resonance wavelength and a non-resonance wavelength of a corresponding gas. Furnace combustion control method. 5. A method for detecting the gas temperature, comprising determining a temperature dependence of an absorption ratio of two adjacent specific wavelength lights of a specific gas type to a gas existing in a flame and a gas hardly existing in a flame. 2. The combustion control method for a combustion furnace according to claim 1, wherein the gas temperature is measured using two gas types. 6. The combustion control method for a combustion furnace according to claim 1, wherein an optical fiber is used for the laser oscillation section or the laser receiving section. 7. A secondary combustion section above the primary combustion section,
In a combustion control device of a waste combustion furnace that controls combustion by supplying primary air and secondary air to each combustion section, one or more laser oscillation / irradiation systems that irradiate light of a specific wavelength in a plurality of directions in a combustion zone in the furnace. Receiving means, means for calculating a cross section of gas concentration or gas temperature in a corresponding combustion control area based on a detection signal from the receiving means, and at least corresponding combustion based on the gas concentration or gas temperature obtained by the calculating means. A combustion control apparatus for a combustion furnace, which controls an amount of primary air or secondary air supplied to a control area. 8. The combustion area is divided into a plurality of combustion control areas, and the air supply means is controlled for each of the plurality of combustion control areas, and the supply control of each air amount supply means is performed based on the gas concentration or the gas temperature. 8. The combustion control method for a combustion furnace according to claim 7, further comprising control means for performing the following. 9. An optical path length of light of a specific wavelength from the laser oscillation means to the reception means is set so as to pass through one or a plurality of combustion control areas, and a plurality of light path lengths obtained by receiving the transmitted light are obtained. 9. The combustion control method for a combustion furnace according to claim 8, wherein the detection signal is calculated to obtain a gas concentration or a gas temperature in a corresponding combustion control area. 10. The combustion control apparatus for a combustion furnace according to claim 7, wherein the measurement of the gas concentration or the gas temperature is performed by a laser spectral absorption method. A plurality of types of laser light having an absorption wavelength of a gas existing in a single or plural types of flames of an existing gas and an absorption wavelength of two gases of a gas hardly present in the flame. A combustion control device for a combustion furnace according to claim 7. 11. The combustion control device for a combustion furnace according to claim 7, wherein the laser light oscillated by the laser oscillating unit is a plurality of types of laser light having a resonance wavelength and a non-resonance wavelength of a corresponding gas. 8. The combustion control device for a combustion furnace according to claim 7, wherein: 12. The combustion control apparatus for a combustion furnace according to claim 7, wherein an optical fiber is used for a laser oscillation section or a laser receiving section.