JP2989367B2 - Combustion control method for waste incinerator - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for controlling combustion in a waste incinerator, and more particularly to a method for controlling a combustion target (hereinafter, referred to as "combustible") using a conveyor.
The present invention relates to a combustion control method for a waste incinerator in which refuse is simply injected into an incinerator.

[0002]

2. Description of the Related Art When waste is incinerated in a waste incinerator, for example, a fluidized bed furnace, if the amount of refuse supplied to the incinerator changes instantaneously, the composition of the exhaust gas from the furnace also changes, and the unburned matter, For example, it causes an increase in the concentration of carbon monoxide (CO) and the generation of harmful chlorine compounds such as dioxin.

[0003] In the combustion control method of a refuse incinerator, it is extremely important to keep the furnace load almost constant. To this end, fluctuations in the amount of waste input are suppressed, and when fluctuations occur, the combustion conditions are adjusted according to the fluctuations. Need to adjust. As a method of detecting the amount of refuse charged into the incinerator, for example, a method using a weighing conveyor that weighs the total weight of the conveyor's own weight and the weight of the refuse on the conveyor with a load cell, or for example, using a photoelectric element in the refuse input chute There is a method in which a plurality of optical paths are formed across the cross section of the chute by mounting, and the amount of waste input is estimated on the basis of the frequency or time, etc., of dust passing through the optical path. Thus, the secondary air supply amount and the like were controlled.

[0004] However, the method using the weighing conveyor has a drawback that a measurement error increases because dust is accumulated and adheres to the conveyor itself and the empty weight gradually increases. In addition, the method using the photoelectric element can be applied to a case where a plurality of dusts block an optical path in parallel or a single dust alone blocks an optical path. However, there is a disadvantage that the measurement accuracy is not so high. Therefore, it is difficult to maintain a stable combustion state even if the combustion conditions are controlled based on the amount of waste input detected by such a method. Further, the method using the photoelectric element detects the amount of dust just before actually falling into the furnace, and even if a large change in the input amount is detected, the Therefore, adjustment of combustion conditions cannot be made in time. That is, immediately after detecting a change in the amount of dust, even if an open / close signal such as an air damper is issued, appropriate combustion conditions cannot be set due to a time delay required for the open / close operation, and unburned components and dioxins, etc. The generation of harmful substances cannot be suppressed sufficiently.

[0005]

The above-mentioned prior arts have a problem that the amount of waste supplied into the furnace cannot be accurately detected in advance, and the optimum combustion conditions corresponding to the amount of waste cannot be set. Was. SUMMARY OF THE INVENTION It is an object of the present invention to solve the above-mentioned problems of the prior art, detect in advance the amount of refuse to be injected into an incinerator, and set a combustion condition in accordance with the detected refuse input amount with a margin in time. it can,
An object of the present invention is to provide a combustion control method for a waste incinerator capable of feedforward control.

[0006]

In order to achieve the above object, a first invention of the present application is to incinerate an object to be burned into an incinerator using a conveyor, and to incinerate an air supply according to a combustion state. In the combustion control method for a waste incinerator for controlling the combustion conditions, a light beam is irradiated from above on the waste to be put into the incinerator using the conveyor, and a direction inclined by a predetermined angle with respect to the light beam. From a monitor with a television camera, the obtained image is analyzed to determine the displacement of the irradiation light point at which the light beam collides with the waste surface with respect to the conveyor surface, and the displacement from the conveyor surface to the waste surface is determined based on the displacement. The present invention relates to a combustion control method for a waste incinerator, which determines a height and controls combustion conditions such as an air supply amount based on the height of the waste.

[0007] A second invention is the first invention, wherein
The amount of waste to be supplied to the incinerator is determined based on the height of the waste, the width of the conveyor, and the speed of the conveyor, and the combustion conditions including air supply are controlled in accordance with the amount of waste. The invention relates to a combustion control method for a waste incinerator.

[0008]

FIGS. 4 to 6 are explanatory views showing the principle of detecting the amount of waste input in the present invention. In FIG. 4, when an object 22 conveyed by a conveyor 21 is irradiated with a light beam 29 from a light source 24 provided thereabove, an irradiation light point A is formed on the upper surface of the object 22. This state is represented by a straight line 26 inclined from the light ray 29 by a predetermined angle θ,
Observed by a television camera 25 arranged on a straight line 26 passing through a projection point B on the conveyor 21 (X axis in FIG. 5)
As shown in FIG. 5, a displacement y corresponding to the height of the object 22 is recognized between the irradiation light point A and the projection point B. Since the displacement y changes in the vertical direction in proportion to the height of the object to be conveyed, the image obtained by the television camera 25 is analyzed by the image analysis device 30 so that the x-axis of the irradiation light point A is sequentially detected. Can be calculated. The height h of the object 22 is obtained based on the displacement y.

That is, in FIG. 4, a triangle ABC is a right-angled triangle having the height h of the object as the hypotenuse, and the length (displacement y) of the side AC changes in proportion to the change in the height h of the object. become. Therefore, the following relationship holds: h = y / sin θ (1)

The height h of the object can be obtained by substituting the displacement y of the irradiation light point A obtained by the image analysis into the equation (1). Usually, the refuse to be charged into the incinerator is continuously charged, and the height of the refuse on the conveyor is h.
It is a guide to increase or decrease the amount of waste input. Therefore, by controlling combustion conditions such as the amount of air supplied to the incinerator based on the height of the refuse, appropriate combustion conditions can be set.

FIG. 6 shows that the height h is obtained based on the position of the irradiation light point A by irradiating a light beam 29 from above the continuously conveyed refuse 28, and the input amount Q of refuse is calculated from the height h. FIG. 9 is an explanatory diagram illustrating a detection method. In the same manner as the method shown in FIG. 4 and FIG.
Ask for. Next, by integrating the height h, the actually measured width w of the conveyor, and the conveyor speed v, a waste supply amount, that is, a waste input amount Q is obtained.

The amount of waste input Q = h × w × v The conveyor speed, air supply amount, etc. are controlled in accordance with the amount of waste input thus determined. That is, when it is detected that a large amount of refuse has been transferred, the conveyor speed is reduced to reduce the amount of refuse, and the amount of primary air supplied to the incinerator is reduced. By suppressing the flow and mixing with the refuse, the rate of thermal decomposition of the refuse is reduced, thereby reducing the amount of combustible gas generated.
On the other hand, if the amount of transferred garbage decreases and the amount of garbage input is expected to decrease, increase the conveyor speed to secure the amount of refuse input and reduce the amount of secondary air supplied to the incinerator. So that the temperature inside the furnace does not decrease.
This stabilizes the combustion state, and suppresses the generation of unburned components such as CO and the generation of harmful substances such as dioxin.

In the present invention, for example, spot light or slit light is used as a light source. For example, by using the slit light, it is possible to detect a plurality of displacements y of the irradiation light point A in the width direction of the conveyor for obtaining the height h of the refuse. Calculating the amount of waste and the amount of dust input significantly improves the detection accuracy. In addition, by increasing the number of measurements in a unit time, the accuracy of detecting the amount of waste input can be improved.

In the present invention, the combustion conditions controlled based on the amount of waste input include, for example, the conveyor speed, the amount of primary air flowing through the fluid medium, the amount of secondary air, and the like.

[0015]

Next, embodiments of the present invention will be described. FIG.
BRIEF DESCRIPTION OF THE DRAWINGS It is an apparatus system diagram which shows one Example of this invention. The apparatus includes an incinerator 1, a supply pipe 3 for primary air 2 supplied to the bottom of the incinerator 1, a fluidized bed 4 formed by the primary air 2, and a dust 16 on top of the fluidized bed 4. Supply pipe 5 for supplying the waste, a conveyor 6 for transferring the waste 16 to the waste supply pipe 5, a motor 7 for driving the conveyor 6, an empty tower 8 above the fluidized bed 4, and an empty tower A secondary air supply pipe 10 having a flow control valve 18 for supplying secondary air 9 to the section 8
And a chimney 11 for discharging combustion exhaust gas passing through an exhaust gas treatment device (not shown) to the atmosphere.
Above the dust supply pipe 5 of the conveyor 6, a light source 12 that irradiates the slit light 19 to the dust 16 conveyed by the conveyor 6 and a television set at a position shifted from the slit light 19 by a predetermined angle θ. A camera 13 is provided, and the television camera 13 is connected to an image analysis device 14.
Reference numeral 15 denotes a combustion control device for controlling combustion conditions, and reference numeral 17 denotes a primary air bypass line.

When incinerating refuse, first, primary air 2 is supplied to the bottom of incinerator 1 through primary air supply pipe 3, and fluidized bed 4 is formed. Next, a conveyor 6 for transferring garbage
The driving motor 7 is driven, and the refuse 16 is charged into the fluidized bed 4 of the incinerator 1 via the refuse supply pipe 5 by the conveyor 6. The refuse 16 introduced into the fluidized bed 4 mixes with the high-temperature sand constituting the fluidized bed 4 and burns.

At this time, detection of the amount of waste input and control of combustion conditions are performed as follows. That is, the dust on the conveyor 6 is irradiated with the slit light 19 from the television camera 12 disposed above the conveyor 6, and a continuous curve of irradiation light points corresponding to the irregularities is formed on the surface of the dust.
FIG. 2 is an explanatory view of detecting the amount of dust input by irradiating the slit light 19 on the surface of the dust 16 input by the conveyor 6, and FIG. 3 is an irradiation light point A captured by the television camera 13 in FIG. FIG. A curve in which the irradiation light points A are continuous represents the surface shape of dust on the conveyor. Data of the irradiation light spot A obtained in this way is sequentially sent to the image analysis device 14 as an irradiation light image signals S ₁ of garbage surface (see FIG. 1). Irradiating light image signals S ₁ sent to the image analyzer 14 is analyzed here, amount of waste height data is obtained. And the amount of waste height data, signals S ₃ and the conveyor width of the conveyor speed detected by speedometer provided in the conveyor drive motor 7 w (constant) and are accumulated in waste input amount Q, i.e. predetermined conveyor dust amount signal S ₂ on the conveyor in the long is obtained. This waste signal S
₂ is sent to the combustion control device 15, on the basis of which the combustion conditions, in particular the amount of waste input, the amount of air supply, etc., are controlled.

In a fluidized bed incinerator, when the amount of combustion in the furnace is large, the furnace pressure and the furnace temperature increase, and the oxygen concentration in the combustion gas in the furnace decreases. On the other hand, when the amount of combustion decreases, the furnace pressure and the furnace temperature decrease, and the oxygen concentration in the combustion gas increases. Therefore, when adjusting the conveyor speed based on the dust signal S ₂ on the conveyor obtained by the image analyzer 14, the dust signal S ₂ is detected by a signal indicating the combustion state in the furnace, for example, by a pressure gauge PG. The furnace pressure signal S ₄ , the oxygen concentration signal S ₅ in the combustion gas detected by the oximeter 20, and the furnace temperature signals S ₆ and S ₇ detected by the thermometers T ₁ and T _2. and controls the conveyor driving motor 7 to adjust the waste input amount by the conveyor speed control signal S ₁₁ which is corrected by the combustion control device 15 based on the like. Dust amount signal S ₂ on the obtained conveyer image analyzer 14 becomes higher than a predetermined value, if the predicted introduction of large amounts of waste, as constant as possible to slow down the conveyor speed to the verge of the dust falling from the conveyor It is controlled so that an amount of refuse is put into the furnace. At this time the feed of primary air quantity adjustment signal S ₁₂ to the valve of the primary air bypass line 17, still better when reducing the supply amount of the primary air 2. In this manner, generation of a large amount of combustible gas due to instantaneous thermal decomposition of a large amount of refuse charged into the furnace is suppressed. On the other hand, becomes equal to or less than a certain value dust amount signal S ₂ on the conveyor, when the predicted small amount of dust dosages, as much as possible a certain amount of dust in the furnace to increase the conveyor speed to the verge of the dust falling from the conveyor Is controlled to be supplied to At this time reducing the amount of secondary air to adjust the secondary air amount adjusting valve 18 by the secondary air amount adjusting signal S ₁₃ still good. In this way, a decrease in the furnace temperature is avoided. The proportion to reduce the secondary air amount is corrected based on the furnace temperature signal S _7, for example, furnace temperature S
₇ when relatively high is controlled to reduce the quantity of secondary air slightly, furnace temperature S ₇ be relatively low is controlled to decrease significantly.

According to this embodiment, the amount of waste immediately before being put into the incinerator can be detected with high precision in advance, and the combustion conditions such as the air supply amount can be controlled based on the detected amount. It is possible to perform stable refuse incineration without any significant change. In this embodiment, based on the standard speed of the conveyor (for example, 6 m / min), 5 to 30 seconds before the dust 16 is put into the furnace, preferably 10 to 10 minutes.
It is preferable to detect the amount of dust input 20 seconds before. Even if the combustion conditions are controlled based on the signal obtained when the measurement is performed after 5 seconds before the introduction of the refuse, the follow-up control is performed. Further, if the amount of dust is detected at least 30 seconds before the dust is charged, it is difficult to adjust the time until the dust is charged into the furnace.

In this embodiment, the predetermined conveyor length when calculating the amount of waste input is preferably 0.3 to 1 m. If it is shorter than 0.3 m, the combustion control becomes too sensitive.
On the other hand, if the length is longer than 1 m, the sensitivity decreases. In the present embodiment, the detection accuracy of the amount of waste input can be classified into, for example, about 10 steps in accordance with the number of detected waste height data, and the combustion conditions can be controlled in proportion to the degree.

[0021]

According to the first aspect of the present invention, the height of the refuse, which is a measure of the amount of refuse to be put into the incinerator, is detected in advance, and the combustion conditions are controlled based on the height. Accordingly, the furnace load is stabilized, and generation of unburned components and the like can be suppressed. According to the invention described in claim 2 of the present application, the amount of refuse to be charged into the furnace is detected in advance, and the combustion conditions are controlled based on the refuse amount signal, so that the furnace load is stabilized and CO The generation of harmful substances such as fuel content and dioicin can be effectively suppressed.

[Brief description of the drawings]

FIG.

FIG.

FIG. 3 is an explanatory view showing one embodiment of the present invention.

FIG.

FIG.

FIG. 6 is an explanatory diagram showing the principle of the present invention.

[Explanation of symbols]

1 ... incinerator, 2 ... primary air, 3 ... primary air supply pipe, 4 ...
Fluidized bed, 5: refuse supply pipe, 6: conveyor, 7: conveyor driving motor, 8: empty tower, 9: secondary air, 10: secondary air supply pipe, 11: chimney, 12: light source, 13 ... TV camera, 14: Image analysis device, 15: Combustion control device, 16
Refuse, 17 Primary air bypass line, 18 Secondary air flow control valve, 19 Slit light, 20 Oxygen meter, S
₁ ... Irradiation light image signal, S ₂ ... Dust amount signal on conveyor,
S ₃ ... conveyor speed signal, S ₄ ... furnace pressure signal, S ₅ ...
Signal of oxygen concentration in combustion gas, S ₆ , S ₇ : furnace temperature signal, S ₁₁ : conveyor speed control signal, S ₁₂ : primary air amount control signal, S ₁₃ : secondary air amount control signal, S ₁₄ : furnace Internal pressure adjustment signal.

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁶ , DB name) F23G 5/50 ZAB

Claims (2)

(57) [Claims] 1. A method for controlling the combustion of a waste incinerator, comprising: injecting the burnable material into an incinerator using a conveyor to incinerate the material; and controlling combustion conditions such as an air supply amount according to a combustion state. While irradiating a light beam from above to the waste put into the incinerator using a conveyor, monitoring with a television camera from a direction inclined by a predetermined angle with respect to the light beam, the obtained image is analyzed and the light beam is analyzed. The displacement of the irradiation light point colliding with the waste surface with respect to the conveyor surface is determined, the height from the conveyor surface to the waste surface is determined based on the displacement, and the air supply amount is determined based on the height of the waste. A method for controlling combustion in a waste incinerator, comprising controlling combustion conditions including the beginning. 2. The amount of waste to be supplied to the incinerator is determined based on the height of the waste, the width of the conveyor and the speed of the conveyor. The combustion control method for a waste incinerator according to claim 1, wherein the combustion condition is controlled.