JP3621805B2 - Combustion control method in fluidized bed incinerator - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a combustion control method in the case of incinerating garbage such as municipal waste and industrial waste in a fluidized bed incinerator.
[0002]
[Prior art]
A fluidized bed incinerator has a larger hearth load than a stoker furnace, has a small loss of ignition, is easy to ignite and stop, and is suitable for incineration of recently diversified garbage. By the way, the burning rate by the fluidized bed is larger than the combustion method in the stoker furnace, so if the amount of waste supply is not kept as constant as possible, for example, if a large amount of waste is temporarily supplied, Since rapid gasification (a large amount of pyrolysis gas is generated), the pressure in the furnace fluctuates greatly or a temporary air shortage occurs, and as a result, the generation of carbon monoxide and dioxins is induced. Therefore, in general, in order to perform good and stable waste combustion in the fluidized bed, the waste is crushed by a crusher, and then the crushed waste is quantitatively supplied to the chute by a waste feeder such as a screw feeder, In general, finely divided waste is quantitatively supplied from the chute.
[0003]
However, even when the waste is completely crushed and subdivided by the crusher, the subdivided garbage is entangled and large while being supplied to the chute from the garbage supply device or while flowing down the chute. It becomes a lump, and the supply amount of garbage into the furnace may temporarily increase or decrease temporarily. Even when waste is supplied quantitatively, there is a large difference in gasification and combustion in the furnace due to recent diversification of the shape, properties, flammability, incombustibility, heat generation, etc. May occur. In addition, it is necessary to roughly crush the garbage to a certain size because it is easy to cause troubles due to wear, damage, etc. of the crushing blade if the garbage is highly subdivided with a crusher. There are also circumstances. Therefore, it is difficult to supply the dust evenly in the fluidized bed incinerator from the viewpoint of weight or volume, and also from the aspect of calorific value. Insufficient or excessive phenomenon is unavoidable.
[0004]
Therefore, various combustion control methods have been proposed and put into practical use in order to suppress the occurrence of such a phenomenon as much as possible. As a conventional combustion control method, for example, (1) a method of sensing the amount of dust passing through the chute by a chute sensor and controlling the dust supply device so that the amount of dust supply becomes constant, and (2) an optical sensor Method of controlling the amount of refuse supply and combustion air according to the combustion status by sensing the brightness in the furnace and using it, or (3) Oxygen concentration of exhaust gas discharged from the furnace Is known, and a method for controlling the amount of dust supply or the amount of secondary air supply based on this is known.
[0005]
[Problems to be solved by the invention]
However, as described above, the volume (supply amount) of the garbage does not necessarily match the calorific value, and there is a large difference in gasification or combustion in the furnace even when the waste is supplied quantitatively. Since this may occur, reliable combustion control cannot be performed by the method (1). In the method (2), the optical sensor is very expensive, and the optical sensor is easily contaminated, which may cause malfunction.
[0006]
On the other hand, in the method (3), oxygen in the exhaust gas accompanies changes in the combustion state in the furnace (for example, when a large amount of waste is supplied, the gasification of the waste proceeds and combustion occurs at a low air ratio). This method utilizes the fact that the concentration also changes, and does not cause the problem of deficiency as described in the above methods (1) and (2). However, on the other hand, when the oxygen concentration is detected (hereinafter referred to as “detection time”) There is a time lag between the actual supply time of waste or secondary air whose supply amount is controlled based on the oxygen concentration, and the control of the appropriate secondary air supply amount according to the combustion situation is possible due to such a control time delay. There was a problem that could not be done.
[0007]
That is, according to the method (3), for example, the detection time t ₁ Oxygen concentration at ₁ Is standard oxygen concentration D ₀ When the value exceeds the value, the secondary air supply amount is controlled to decrease, but the oxygen concentration of the exhaust gas changes with time as shown in FIG. Time point T ₁ In oxygen concentration D ₁ Is standard oxygen concentration D ₀ May result in a situation where the secondary air supply amount must be increased. In such a case, as a result, the secondary air shortage is promoted by the control. Conversely, detection time t ₂ Oxygen concentration at ₂ Is standard oxygen concentration D ₀ The secondary air supply amount was controlled to increase because it was less than ₂ In oxygen concentration D ₂ Is standard oxygen concentration D ₀ In some cases, the amount of secondary air supply must be reduced, and in this case, as a result, excessive secondary air is promoted. Since the oxygen concentration of the exhaust gas changes with time in this way, at a certain time t ₁ , T ₂ Oxygen concentration at ₁ , D ₂ Even if the secondary air supply amount is controlled based on the detected value, it is the air volume corresponding to the past oxygen concentration, not the actual air volume desired. In other words, the controlled air volume is not adapted to the actual combustion situation when it is supplied into the furnace, but to the combustion situation traced back to the past by the time corresponding to the above control time delay. Only. Thus, the detection time t ₁ , T ₂ Time T controlled from ₁ , T ₂ As a result of the control time delay Δt up to this point, proper combustion control cannot be performed depending on the method (3). As illustrated above, the control deteriorates the combustion situation (secondary air). It was also conducive to deficiencies or excesses).
[0008]
Such a problem also occurs when the amount of waste supply is controlled by the method (3). That is, even if the waste supply device is controlled based on the oxygen concentration of the exhaust gas, the information (oxygen concentration) used as a reference for the control is not the information at the time of supply but the past, and is based on the oxygen concentration at the time of detection. The controlled amount of waste is not what you really want. Although it is not uniform depending on the scale, structure, etc. of the incinerator, generally, it takes 10 to 30 seconds to enter the furnace through the chute from the garbage supply device. It will take about 5 seconds for the garbage to burn and the exhaust gas to reach the oxygen concentration detector, and then it will take about 5 seconds for the control to be completed, totaling about 20-40 seconds. The combustion state when there is a control time delay and an actual controlled amount of dust or secondary air is supplied into the furnace is completely different after about 20-40 seconds from the time of detection of the oxygen concentration. It has become.
[0009]
The present invention provides a combustion control method in a fluidized bed incinerator capable of solving such a problem, particularly the problem due to the control time delay in the method (3), and performing appropriate control according to the actual combustion situation. It is intended to provide.
[0010]
[Means for Solving the Problems]
The invention of claim 1 of the present application By a control system comprising an oxygen concentration detector, an oxygen concentration / oxygen concentration change rate detector, and a control signal corrector comprising a function part and a function selection part, When controlling at least one of the waste supply amount and secondary air supply amount to the fluidized bed incinerator according to the combustion state in the furnace, correction by a plurality of oxygen concentrations previously classified according to the oxygen concentration change rate First, the oxygen concentration of the exhaust gas discharged from the fluidized bed incinerator and the rate of change of the oxygen concentration are detected. Changes in this detected oxygen concentration Based on rate A correction function that best matches the detected oxygen concentration change rate is selected from the correction functions based on the plurality of oxygen concentrations, and a correction coefficient corresponding to the oxygen concentration at the time of detection is obtained using the selected correction function. By correcting the control signal of the waste supply amount or the secondary air supply amount based on the correction coefficient, and outputting the corrected control signal to the waste supply device or the secondary air control device, At least one of the waste supply amount or the secondary air supply amount, At the time of actual waste or secondary air supply The basic configuration of the present invention is that the control is performed according to the combustion state.
Further, the invention of claim 2 is the invention of claim 1, wherein both the waste supply amount and the secondary air supply amount are the same. According to the state of combustion at the time of actual waste and secondary air supply It is intended to control.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be specifically described below with reference to FIGS.
[0012]
FIG. 1 shows a waste incineration plant to which a combustion control method (hereinafter referred to as “first method”) according to the present invention in the first embodiment is applied. In this plant, the waste 1 is a screw. The fluid is supplied to the fluidized bed combustion furnace 4 through a chute 3 by a waste supply device 2 such as a feeder. The waste supply device 2 is controlled by a control signal 5 a output from the waste supply amount regulator 5 so that the amount of waste supply from the chute 3 to the furnace 4 can be increased or decreased. In addition, in the case where the waste heat boiler is attached to the plant, the waste supply amount adjuster 5 is a gas cooling chamber in the case where the information 5b regarding the boiler pressure and the amount of boiler evaporation or the waste heat boiler is not attached. The information 5b such as the amount of water jetted water is input, and the control of the waste supply device 2, that is, the increase / decrease control of the waste supply amount is performed in consideration of the information 5b.
[0013]
Further, in the fluidized bed combustion furnace 4, a fluidized bed 8 made of a granular fluidized medium such as silica sand and alumina is formed by supplying primary air 7 from the bottom of the furnace with a primary air blower 6. The waste 1 supplied from the chute 3 into the furnace 4 is incinerated while stirring and flowing in the fluidized bed 8, and the unburned gas (pyrolysis gas) etc. is incinerated in the furnace on the fluidized bed 8. In the secondary combustion region, which is the region, the secondary air 10 is supplied by the secondary air supply device 9 to complete combustion (secondary combustion). The exhaust gas generated in the furnace 1 is discharged from the flue 11. The secondary air supply device 9 includes a damper 14 and an air flow rate detector 15 arranged in a secondary air supply path 13 extending from the secondary air blower 12 to the secondary combustion region, and a control output from the air volume adjuster 16. By controlling the damper 14 by the signal 16a, the secondary air supply amount can be increased or decreased.
[0014]
In the first method, the future is planned from the past detection value as follows, and the waste supply amount and the secondary air amount are controlled.
[0015]
Thus, in the first method, the oxygen concentration detector 17, the oxygen concentration / oxygen concentration change rate detector 18, the control signal correctors 19 and 20 including the function units 19 a and 20 a and the function selection units 19 b and 20 b are provided. The control system that detects the oxygen concentration change rate of the exhaust gas 1a at a certain detection time, predicts the combustion state after the control time delay from this oxygen concentration change rate, and supplies the garbage corresponding to the predicted combustion state The quantity and the secondary air supply quantity are obtained, and the dust supply quantity and the secondary air supply quantity are controlled while predicting the future combustion state from the past detection data.
[0016]
The oxygen concentration detector 17 is disposed in the flue 11 and detects the oxygen concentration of the exhaust gas 1 discharged from the furnace 4. The oxygen concentration / oxygen concentration change rate detector 18 has a rate of change from the oxygen concentration detected by the oxygen concentration detector 17, that is, a rate of increase or decrease in concentration when the oxygen concentration tends to increase. In this case, the concentration reduction rate is detected, and the detected oxygen concentration change rate is output as the oxygen concentration change rate signals 21b and 22b to the function selection units 19b and 20b, and the oxygen concentration is a function as the oxygen concentration signals 21a and 22a. It outputs to the part 19a, 20a.
[0017]
The function units 19a and 20a of the control signal correctors 19 and 20 include a correction function f based on a plurality of oxygen concentrations classified in advance according to the oxygen concentration change rate. ₁ , F ₂ ...... f _n Is remembered. Correction function f ₁ , F ₂ ...... f _n As shown in FIGS. 3 (A) and 3 (B), this is a function of a correction coefficient for the oxygen concentration, and an appropriate one corresponding to the oxygen concentration change rate is assumed assuming various oxygen concentration change rates. A number is set.
[0018]
For example, the correction function corresponding to the oxygen concentration change rate indicating the increasing tendency is different from the oxygen concentration changing rate, the one having the same increasing tendency as the oxygen concentration changing rate, the lower or higher increasing trend, and the oxygen concentration changing rate. The correction function corresponding to the oxygen concentration change rate indicating a decreasing trend is one that has a decreasing trend equivalent to the oxygen concentration changing rate, one that is lower or higher than this, and There are things that turn to an increasing trend, unlike the oxygen concentration change rate. These correction functions f ₁ , F ₂ ...... f _n Is set, for example, based on actual operation data obtained by the incinerator 4 or a fluidized bed incinerator substantially the same as the incinerator 4.
[0019]
Further, the function selectors 19b and 20b of the control signal correctors 19 and 20 are signal switches, and the function of the function is obtained by inputting the oxygen concentration change rate signals 23 and 24 from the oxygen concentration / oxygen concentration change rate detector 18. A plurality of correction functions f in the sections 19a and 20a ₁ , F ₂ ...... f _n From this, one that best matches the oxygen concentration change rate detected by the oxygen concentration / oxygen concentration change rate detector 18 is selected.
[0020]
That is, the correction function is selected depending on how the oxygen concentration at the detection time point is increasing or decreasing. For example, as shown in FIG. _x , T _y Even if the same oxygen concentration d is detected in FIG. 3, the correction function selected differs depending on the oxygen concentration change rate at that time, and as shown in FIG. _x Then, oxygen concentration change rate K _x Indicates an increasing trend, the correction function f that best fits the increasing rate _x Is selected (Fig. A) and the other detection time t _y Then, oxygen concentration change rate K _y Indicates a decreasing trend, the correction function f that best fits the decreasing rate _y Is selected (FIG. B). Of course, the acidity concentration ratio K showing an increasing tendency _x As described above, the correction function f indicating the increasing tendency is always detected even when _x Is not always selected. For example, a correction function that tends to decrease depending on the increase rate of the oxygen concentration may be selected. Similarly, acidity concentration ratio K showing a decreasing tendency _y As described above, the correction function f indicating the decreasing tendency is always detected even when _y Is not always selected. For example, a correction function that tends to increase depending on the decrease rate of the oxygen concentration may be selected.
[0021]
In this way, the oxygen concentration that changes with time and the oxygen concentration change rate that is the tendency of the change are read, and the correction function that best matches the oxygen concentration change rate is selected. Detection time t _x Oxygen concentration change rate K _x Based on the optimal correction function f _x Is selected at that time t _x Correction coefficient A corresponding to the oxygen concentration d in _x Accordingly, the control signals 5a and 16a output from the regulators 5 and 16 to the dust supply device 2 or the damper 14 are corrected, and the dust supply device 2 and the damper are corrected by the corrected control signals 5'a and 16'a. 14 is controlled. That is, the control signal correctors 19 and 20 output the control signals 5a and 16a output from the adjusters 5 and 16 to the dust supply device 2 or the damper 14 from the time point based on the oxygen concentration change rate at the time of detection. The combustion state at the time when the time corresponding to the control time delay has elapsed is predicted, and correction is performed so that the dust supply amount or the secondary air supply amount corresponding to the predicted combustion state is obtained. In other words, the oxygen concentration d is detected at the detection time t. _x From time T corresponding to the control time delay Δt _x Then D _x The oxygen concentration change rate K _x That is, the oxygen concentration change rate K _x Correction function f that best fits _x And a correction coefficient A suitable for the oxygen concentration d _x And the control signals 5a and 16a with the oxygen concentration D _x The control signals 5'a and 16'a are corrected so as to obtain a dust supply amount or a secondary air amount that should be supplied in the combustion state where the exhaust gas 1a is generated (FIGS. 2 and 3A). reference). Similarly, the second detection time t described above _y Oxygen concentration change rate K _y Based on the optimal correction function f _y Is selected at that time t _y Correction coefficient A corresponding to the oxygen concentration d in _y Accordingly, the control signals 5a and 16a output from the regulators 5 and 16 to the dust supply device 2 or the damper 14 are corrected, and the dust supply device 2 and the damper are corrected by the corrected control signals 5'a and 16'a. 14 is controlled (see FIGS. 2 and 3B).
[0022]
By the way, the waste 1 is supplied to the fluidized bed incinerator 4 continuously through the chute 3 with a constant amount and a constant calorific value, and a predetermined amount of primary air 7 and secondary air 10 are supplied, If complete combustion occurs, the amount of oxygen contained in the exhaust gas 1a becomes a constant value. However, as described above, since the waste 1 varies in quality, quantity, and calorific value, combustion is not constant, and therefore the amount of oxygen in the exhaust gas 1a changes every moment. The amount of oxygen is detected, and based on this, the waste supply device 2 controlled by the waste supply amount adjuster 5 is controlled to change the waste supply amount, and the secondary air supply amount is controlled. In this case, the problem is that, as described at the beginning, 10 to 30 seconds from the supply device 2 through the chute 3 to the furnace 1 until the combustion in the furnace 1 reaches the oxygen concentration detector 20. There is a control time delay of about 20 to 40 seconds in total, about 5 seconds in the instrument, about 5 seconds in the instrument. That is, when the waste supply amount and the secondary air amount are actually controlled, it is already after 20 to 40 seconds have passed, and at that time, it is already in a different state. .
[0023]
According to the first method, such a problem can be solved, but the method is as follows.
[0024]
For example, as shown in FIG. _x Oxygen concentration d and oxygen concentration change rate K _x Is detected by the oxygen concentration / oxygen concentration change rate detector 18, the oxygen concentration change rate signal 21 b, is sent from the oxygen concentration / oxygen concentration change rate detector 18 to the function selectors 19 b, 20 b of the control signal correctors 19, 20. 22b is output, and the oxygen concentration change rate K is output from the function units 19b and 20b. _x Correction function f that best fits _x Is selected. Correction function f _x Is selected by the oxygen concentration signals 21a and 22a output from the oxygen concentration / oxygen concentration change rate detector 18 to the function units 19a and 20a of the control signal correctors 19 and 20, respectively. _x Correction coefficient A commensurate with the oxygen concentration d _x The control signals 5a and 16a output from the regulators 5 and 16 to the dust supply device 2 and the damper 14 are corrected, and the dust supply device 2 is corrected by the corrected control signals 5'a and 16'a. And the damper 14 is controlled.
[0025]
At this time, the corrected control signals 5′a and 16′a are detected at the detection time t. _x This is not to obtain the amount of waste supply and secondary air supply according to the actual combustion situation in the case of oxygen concentration change rate K _x Predicted combustion state, that is, detection time t _x In order to obtain a waste supply amount and a secondary air supply amount according to the combustion state at the time when the time corresponding to the control time delay has elapsed or the combustion state predicted to be close to this, the waste supply device 2 and The damper 14 is controlled. That is, by detecting the change rate of the oxygen concentration at the time of detection, the oxygen concentration at the subsequent time, that is, when the waste 1 and the secondary air 10 are actually supplied to the furnace 1 is predicted, and the amount of waste supplied And the secondary air supply can be determined.
[0026]
Therefore, by controlling the waste supply amount and the secondary air supply amount by the first method, the problem due to the control time delay as described above (for example, as described at the beginning, it is encouraged to overcome the shortage or excess of secondary air. The control time delay is substantially eliminated, and the supply amount of the waste 1 and the secondary air 10 into the furnace 1 is changed to the actual combustion state at the time of supply or to this. It can be adapted to the approximation, and good and stable combustion can be performed.
[0027]
By the way, in the first method, the waste supply amount and the secondary air supply amount are controlled, but only one of them can be controlled based on the oxygen concentration change rate. That is, in the combustion control method according to the present invention in the second embodiment (hereinafter referred to as “second method”), as shown in FIG. 4, only the waste supply amount is controlled based on the oxygen concentration change rate. In the combustion control method according to the present invention in the third embodiment (hereinafter referred to as “third method”), as shown in FIG. 5, only the secondary air supply amount is controlled based on the oxygen concentration change rate. I have to.
[0028]
Since the control method in the second method or the third method is basically the same as that in the first method, the details thereof are omitted, but are as follows.
[0029]
That is, in the second method, as shown in FIGS. _x Oxygen concentration d and oxygen concentration change rate K _x Is detected by the oxygen concentration / oxygen concentration change rate detector 18, the oxygen concentration change rate signal 21b is output from the oxygen concentration / oxygen concentration change rate detector 18 to the function selection unit 19b of the control signal corrector 19. In the function part 19b, the oxygen concentration change rate K _x Correction function f that best fits _x Is selected. Correction function f _x Is selected based on the oxygen concentration signals 21a and 22a output from the oxygen concentration / oxygen concentration change rate detector 18 to the function unit 19a of the control signal corrector 19, the detection time t _x Correction coefficient A commensurate with the oxygen concentration d _x And the control signal 5a output from the waste supply amount regulator 5 to the waste supply device is corrected, and the waste supply device 2 is controlled by the corrected control signal 5'a. The corrected control signal 5′a is detected at the detection time t. _x It does not obtain the amount of waste supply according to the actual combustion situation in Japan, but the oxygen concentration change rate K _x Predicted combustion state, that is, detection time t _x The waste supply device 2 is controlled so as to obtain a waste supply amount corresponding to the combustion state at the time when the time corresponding to the control time delay elapses or the combustion state predicted to be close thereto. That is, by detecting the change rate of the oxygen concentration at the time of detection, the amount of waste supply can be determined by predicting the oxygen concentration at the subsequent time, that is, when the waste 1 is actually supplied to the furnace 1. It is. Therefore, by controlling the waste supply amount by the second method, the control time delay is substantially eliminated as in the first method, and the supply amount of the waste 1 into the furnace 1 is reduced at the time of supply. It can be adapted to the actual combustion situation or an approximation thereof, and good and stable combustion can be performed.
[0030]
Further, in the third method, as shown in FIGS. _x Oxygen concentration d and oxygen concentration change rate K _x Is detected by the oxygen concentration / oxygen concentration change rate detector 18, the oxygen concentration change rate signal 22b is output from the oxygen concentration / oxygen concentration change rate detector 18 to the function selection unit 20b of the control signal corrector 20. In the function part 20b, the oxygen concentration change rate K _x Correction function f that best fits _x Is selected. Correction function f _x Is selected by the oxygen concentration signal 22a output from the oxygen concentration / oxygen concentration change rate detector 18 to the function unit 20a of the control signal corrector 20, the detection time t _x Correction coefficient A commensurate with the oxygen concentration d _x Is found, the control signal 16a output from the air flow regulator 16 to the damper 14 is corrected, and the damper 14 is controlled by the corrected control signal 16'a. The corrected control signal 16′a is detected at the detection time t. _x Does not obtain the secondary air supply amount according to the actual combustion situation at the oxygen concentration change rate K _x Predicted combustion state, that is, detection time t _x The damper 14 is controlled so as to obtain a secondary air supply amount corresponding to the combustion state at the time when the time corresponding to the control time delay elapses or the combustion state predicted to be close thereto. That is, by detecting the change rate of the oxygen concentration at the time of detection, the oxygen concentration at the subsequent time, that is, the time when the secondary air 10 is actually supplied to the furnace 1 is predicted, and the amount of secondary air supply is determined. Can be determined. Therefore, by controlling the secondary air supply amount by the third method, the control time delay is substantially eliminated as in the first method, and the supply amount of the secondary air 10 into the furnace 1 is reduced. It can be adapted to the actual combustion situation at the time of supply or an approximation thereof, and good and stable combustion can be performed.
[0031]
【The invention's effect】
As understood from the above description, according to the method of the present invention, the change rate of the oxygen concentration in the exhaust gas is detected, and both the waste supply amount and the secondary air supply amount are detected based on this oxygen concentration change rate. By controlling one of them, the problem of time delay can be solved by making these supply amounts approximately precede the amount at a future time point from the detection time point. Therefore, even if the amount of waste supplied to the fluidized bed incinerator changes, combustion control according to this can be performed, which can contribute to stabilization of combustion in the fluidized bed incinerator.
[Brief description of the drawings]
FIG. 1 is a system diagram showing a control system for implementing a first method.
FIG. 2 is a curve diagram illustrating a change in acidity concentration of exhaust gas.
FIG. 3 is a curve diagram illustrating a correction function.
FIG. 4 is a system diagram showing a control system that implements a second method;
FIG. 5 is a system diagram showing a control system that implements a third method;
FIG. 6 is a change curve diagram of exhaust gas acidity concentration.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Waste, 1a ... Exhaust gas, 2 ... Waste supply device, 3 ... Chute, 4 ... Fluidized bed incinerator, 5 ... Waste supply amount regulator, 5a, 16a ... Control signal, 5'a, 16'a ... Corrected Control signal, 7 ... primary air, 8 ... fluidized bed, 9 ... secondary air supply device, 10 ... secondary air, 11 ... flue, 13 ... secondary air supply path, 14 ... damper, 16 ... air volume regulator , 17 ... oxygen concentration detector, 18 ... oxygen concentration / oxygen concentration change rate detector, 19, 20 ... control signal corrector, 19a, 20a ... function unit, 19b, 20b ... function selection unit, 21a, 22a ... oxygen concentration Signal, 21b, 22b ... oxygen concentration change rate signal.

Claims (2)

The control system comprising an oxygen concentration detector, an oxygen concentration / oxygen concentration change rate detector, and a control signal compensator having a function unit and a function selection unit allows the amount of waste to be supplied to the fluidized bed incinerator and the secondary In the case of controlling at least one of the air supply amounts according to the combustion state in the furnace, a correction function based on a plurality of oxygen concentrations classified according to the oxygen concentration change rate is obtained in advance, and first from the fluidized bed incinerator. detecting a change of oxygen concentration and the oxygen concentration of exhaust gas discharged, then on the basis of the detected oxygen concentration change rate, the oxygen concentration change rate detected from the correction function by the plurality of oxygen concentration The most suitable correction function is selected, and a correction coefficient corresponding to the oxygen concentration at the detection time is obtained using the selected correction function, and the control of the waste supply amount or the secondary air supply amount is performed based on the correction coefficient. No. corrected by outputting a control signal after the correction to the waste feeder, or the secondary air control unit, at least one of the waste supply amount or the secondary air supply, the actual waste or secondary air A combustion control method in a fluidized bed incinerator, characterized in that control is performed according to the combustion state at the time of supply . 2. A combustion control method in a fluidized bed incinerator according to claim 1, wherein both the waste supply amount and the secondary air supply amount are controlled according to the actual state of combustion of the waste and the secondary air. .

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