JPH0642726A - Combustion amount detecting device and combustion control device for fluidized bed type furnace - Google Patents

Abstract

PURPOSE:To enable an instantaneous accurate sensing of a combustion state within a fluidized bed type furnace to be carried out by a method wherein a brightness within the furnace is detected and the combustion amount of incinerated item within the furnace is detected. CONSTITUTION:A brightness sensing sensor 14-1 may detect brightness within a furnace 1 caused by combustion of ignited item A fed from a supplying feeder 12 into the furnace 1. Due to this fact, its fixing position is located at a place where it is sufficiently above an air nozzle 8 for blowing air into an upper part spacing of a fluidized bed 2 as well as in a secondary air feeding pipe 18 and an entire cross sectional surface of the furnace 1 can be seen. An adjustor 13 may adjust a degree of opening of a control valve 7 in response to a measured value of the brightness sensing sensor 14-1 for use in sensing brightness within the furnace 1. That is, as brightness within the furnace 1 is increased, the adjuster 13 releases the control valve 7, bypasses a part of the air amount blown from an air chamber 6 and blows it from the air nozzle 8 into the upper spacing of the fluidized bed 2 through a pipe 16. In this way, it is possible to perform an accurate measurement of the combustion amount within the furnace.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention detects the combustion state of the incineration material that is put into the furnace in a fluidized bed furnace that incinerates the incinerated material while flowing the fluidized medium such as sand from the lower part of the hearth with air. The present invention relates to a combustion amount detection device and a combustion control device for a fluidized bed furnace.

[0002]

2. Description of the Related Art Conventionally, a fluidized bed incinerator has been used for incineration of city refuse, and when burning city refuse in this fluidized bed incinerator, the garbage is continuously fed to the fluidized bed incinerator. Garbage is often entangled with each other due to its nature, and is often thrown into a large lump in a moment. The fluidized bed incinerator is an incinerator with an extremely high burning rate,
It has the advantage of burning very well, but this can be a drawback on the contrary. That is, since the combustion performance is good, when a combustion product is put into the fluidized bed, a fast product burns in just a few seconds. Therefore, if the quantitativeness of the feeder that supplies the incinerator into the furnace is poor, there is a problem that the variation of the input amount of the incineration directly leads to the variation of the oxygen concentration in the combustion gas.

Depending on the type of fluidized bed incinerator, carbon monoxide and hydrocarbons such as methane, ethylene, propylene, acetylene and benzene cannot be completely burned when the oxygen concentration in the flue gas falls below approximately 5%. Will be discharged to. In addition, since substances such as ammonium chloride and ammonium hydroxide are also produced, white smoke will be emitted from the chimney.

[0004]

In order to deal with the problem that the advantage of the extremely high burning rate of the fluidized bed incinerator is a drawback, and to perform the combustion control without causing the above problem, the It is necessary to instantaneously detect the combustion amount in the floor incinerator (combustion amount of incineration material per unit time) and perform supply control of, for example, the primary air amount or the secondary air amount suitable for the combustion state. However, conventionally, there is no means for instantaneously and accurately detecting the combustion state in a fluidized bed incinerator, and especially in a fluidized bed incinerator that incinerates municipal solid waste, there is no variation in the oxygen concentration in the combustion gas, and there is no whiteness from the chimney. It was difficult to accurately control the combustion so that no smoke was emitted.

The present invention has been made in view of the above points, and an object thereof is to provide a combustion amount detection device and a combustion control device for a fluidized bed furnace capable of instantaneously and accurately detecting the combustion state in the fluidized bed furnace. To do.

[0006]

In order to solve the above problems, the present invention is directed to the inside of the furnace of a fluidized bed furnace in which the fluidized medium is made to flow by the air sent from the lower part of the fluidized bed, and the incinerator charged into the furnace is burned. A combustion amount detecting device for detecting a combustion amount, comprising brightness detecting means for detecting brightness in a furnace, and detecting a combustion amount of incineration material in the furnace from an output of the brightness detecting means. And

Further, the brightness detecting means is provided at a position overlooking the entire cross section of the furnace.

Further, the brightness detecting means is provided at a position which is not affected by the brightness due to the fluid medium or the furnace wall.

Further, the brightness detecting means furnace is provided at or near the top of the furnace.

Further, the brightness detecting means is provided above the secondary air blowing position.

Further, there is provided a combustion amount detecting device for detecting the combustion amount in the furnace of a fluidized bed furnace in which the fluidized medium is made to flow by the air sent from the lower part of the fluidized bed to combust the incinerated substances thrown into the furnace. The brightness detection means for detecting the brightness in the interior and the detection means for detecting the oxygen concentration in the exhaust gas, the pressure in the furnace, and the property, shape, volume and amount of the incineration material thrown into the furnace are provided. And a detection means for detecting the oxygen concentration in the exhaust gas, the pressure in the furnace, and the property, shape, volume and amount of the incinerator that is put into the furnace, whichever is larger. To do.

Also, the output of the combustion amount detecting device described in any one of the above is used as a control signal of the combustion control device of the fluidized bed furnace.

[0013]

According to the present invention, by adopting the above construction, the incinerated matter is put into the fluidized bed, the incinerated matter is gasified in the fluidized bed, and when the gas burns, a flame is generated. Since the flame intensity changes instantaneously according to the combustion amount, the combustion amount in the fluidized bed incinerator can be instantly and accurately measured by detecting the flame intensity with the brightness detecting means.

In addition to the brightness detecting means for detecting the brightness in the furnace, a pressure detecting means for detecting the pressure in the furnace is provided.
By detecting the combustion amount in the furnace by the larger one of the outputs of the brightness detection means and the pressure detection means, the in-furnace pressure becomes high when the combustion amount is large and becomes low when the combustion amount is small. Even if smoke is generated in the furnace and it becomes dark and the brightness detection means cannot detect the accurate combustion amount, the pressure detector has a function of compensating for it.

[0015]

Embodiments of the present invention will be described below with reference to the drawings. In a fluidized bed incinerator, it is extremely difficult to directly measure the combustion amount of the combustion target. This combustion amount (combustion amount per unit time) is closely related to the brightness in the furnace, the oxygen concentration in the exhaust gas, and the furnace pressure. 1 (A),
(B) and (C) are the brightness L in the furnace, which represents the combustion amount in the fluidized bed incinerator, the oxygen concentration E in the exhaust gas, and the furnace pressure P.
It is a figure which shows the relationship of. In the figure, the horizontal axis is time t (1 scale is 5
Seconds). As shown in the figure, in a fluidized bed incinerator,
The brightness L in the furnace, the oxygen concentration E in the exhaust gas, and the furnace pressure P change according to the fluctuation of the combustion amount. Especially the brightness L in the furnace
Faithfully reflects the amount of combustion instantly. Therefore, the present invention is
This is a combustion amount detection device capable of instantaneously detecting the combustion amount by providing a brightness detection sensor, detecting the brightness L in the furnace, and estimating the combustion amount in the fluidized bed incinerator from its output. In addition to the brightness detection sensor, a pressure detection sensor for detecting the pressure inside the furnace is provided, and the brightness detection sensor is complemented by the output of the pressure detection sensor. Thereby, the combustion amount can be detected more accurately.

FIG. 2 is a diagram showing a schematic construction of a fluidized bed incinerator for controlling combustion equipped with a combustion amount detecting device of the present invention. In the figure, reference numeral 1 is a furnace, and inside the furnace 1, a fluidized bed 2 in which a fluid medium such as sand flows is formed. An air chamber 6 is provided below the fluidized bed 2,
The fluidized medium is made to flow by sending fluidized air from a flow blower (not shown) through the pipe 5 into the furnace 1 through the air chamber 6. This blower is, for example, a centrifugal blower, and is preferably controlled so that the air volume becomes constant during operation.

Reference numeral 14-1 is a brightness detection sensor attached to the furnace top in the furnace 1 or mounted near the furnace top to detect the brightness. The mounting position of the brightness detection sensor 14-1 is not limited to the furnace top or the vicinity of the furnace top, and is supplied from the supply feeder 12 into the furnace 1 without being affected by the brightness due to the fluid medium or the furnace wall. Furnace 1 for burning incinerated waste A
Secondary air inlet piping 18 so that the brightness inside can be detected
It is installed at a position sufficiently above the air nozzle 8 for blowing air into the upper space of the fluidized bed 2 and overlooking the entire cross section of the furnace 1.

Reference numeral 13 is an adjuster for adjusting the opening of the control valve 7 based on the measured value of the brightness detecting sensor for detecting the brightness in the furnace 1. Reference numeral 11 denotes an incineration material input hopper for inputting incineration material such as municipal waste, and a supply feeder 1 for supplying the incineration material into the furnace 1 below the incineration material input hopper 11.
Two are provided. Further, in FIG. 1, EG represents exhaust gas discharged from the exhaust gas outlet portion, and AS represents ash discharged from the ash outlet portion.

In the fluidized bed incinerator having the above-mentioned structure, the incinerated material A introduced into the furnace 1 from the supply feeder 12 is the fluidized bed 2
Above it is pyrolyzed, gasified and burned, producing a flame. Since the flame makes the inside of the furnace 1 brighter, it is possible to detect the combustion amount in the furnace 1, that is, the combustion amount by detecting the brightness. Moreover, since the combustion and the generation of the flame are substantially simultaneous, detecting the brightness in the furnace 1 by the brightness detection sensor 14-1 makes it possible to instantaneously detect the combustion amount in the furnace 1.

The combustion control of the fluidized bed incinerator is such that the combustion amount of the incineration material in the furnace 1 is maintained at a predetermined amount regardless of the amount of the incineration material A fed from the supply feeder 12. . The operation will be described below. When the incineration A input from the supply feeder 12 is larger than usual,
Since the combustion amount (per unit time) of the incinerated material A becomes large, the inside of the furnace 1 becomes brighter than usual, and the brightness detection sensor 1
The output of 4-1 becomes large. When the brightness inside the furnace 1 becomes large, the controller 13 opens the control valve 7 and opens the air chamber 6
A part of the amount of air blown from is bypassed and blown into the upper space of the fluidized bed 2 from the air nozzle 8 through the pipe 16.

As a result, the amount of air sent from the air chamber 6 to the fluidized bed 2 is reduced, the flow of the fluidized medium in the fluidized bed 2 is slowed, the amount of heat transferred from the fluidized medium to the incinerated material A is reduced, and the incinerated material A is reduced. The gasification rate of is slowed. That is, the burning speed becomes slow. At this time, by reducing the amount of air from the air chamber 6, the amount of oxygen in the fluidized bed 2 is reduced, and unburned gas is increased accordingly. However, by increasing the amount of air blown from the air nozzle 8, the freeboard portion is increased. This unburned gas in the upper space of the fluidized bed 2, such as 9, will burn.

In the fluidized bed incinerator, the combustion amount and the in-furnace pressure have a close relationship as shown in FIG. 1 (C). That is, as the combustion amount increases, the furnace pressure increases, and when the combustion amount decreases, the furnace pressure decreases. FIG. 3 is a diagram showing a schematic configuration of a fluidized bed incinerator that performs combustion control by detecting the combustion amount of combustion products by detecting the pressure in the furnace 1. In FIG. 3, the same reference numerals as those in FIG. 2 indicate the same or corresponding portions. As shown in the figure, a pressure detection sensor 14-2 that detects the pressure inside the furnace 1 is provided above the fluidized bed 2, and the output of the pressure detection sensor 14-2 is input to the controller 13.

In the above fluidized bed incinerator, when the amount of the incinerated material A put in the furnace 1 is large, the combustion amount of the incinerated material A (per unit time) is large, so that the amount of exhaust gas generated is increased. Then, as can be seen from FIG. 1C, the internal pressure of the furnace 1 becomes high, and the output of the pressure detection sensor 14-2 also becomes large.
When the internal pressure of the furnace 1 increases, the controller 13 opens the control valve 7 to increase the amount of air blown from the air nozzle 8 into the upper space of the fluidized bed 2. The operation by this is the same as in the case of FIG.

In the example of the fluidized bed incinerator shown in FIGS. 2 and 3, the brightness detection sensor 14-1, which detects the combustion amount of the incinerator in the furnace 1,
This is an example in which the pressure detection sensor 14-2 detects and controls, but other than that, as shown in FIG.
The output value PV _{O1 of} 4-1 is given by a calculator Y _O1 to which a symbol a is added, for example, a coefficient k (0 to 2.0) for the brightness signal.
There is also a method in which the opening of the control valve 7 is adjusted by multiplying by the output signal y _O1 proportional to the brightness.

In this case, there is no problem when the incinerated materials such as municipal waste are continuously supplied into the furnace, but due to the nature of the municipal waste, a large amount of garbage is thrown in due to the so-called "falling shavings" due to entanglement, and sudden Smoke etc. generated due to various combustion, the inside of the furnace gets dark even though combustion is active, and the brightness detection sensor 14-1 outputs an erroneous signal indicating that combustion is inactive, and controls The opening degree of the valve 7 may be out of order.

In order to solve the above problem, the pressure in the furnace tends to rise when combustion becomes vigorous, so that the brightness detection sensor 14-1 and the pressure detection sensor 1 as shown in FIG.
The output value P of the pressure detection sensor 14-2 corresponding to the pressure in the furnace is calculated by the calculator Y _O2 having a combination of 4-2 and the symbol b.
When V _O2 exceeds a certain set value, an output signal y _O2 is output to open the opening of the control valve 7 which has been the minimum opening until now to a fixed opening. Since the pressure inside the furnace is normally controlled here, it immediately drops and falls below the set value. When the output signal value PV _O2 of the pressure detection sensor 14-2 decreases and _remains below a certain set value for a predetermined time, the output signal value y _O2 of the minimum opening to the control valve is output. The output signal values y _O1 and y _O2 are compared by the computing unit Y _O3 with the reference sign c, and a large signal value is output as the output signal value y _O3 , and the opening of the control valve 7 is adjusted by the output signal y _O3. It By performing such control, even if smoke or the like is generated and the inside of the furnace 1 becomes dark, the control valve 7 is opened to a constant opening and works effectively, so that desirable combustion control is possible.

In the above embodiment, the brightness detection sensor 1
An example in which the amount of combustion in the furnace 1 is detected by the output of 4-1 and the amount of air sent from the air chamber 6 to the fluidized bed 2 is controlled via the control valve 7 has been shown. Since the brightness in the furnace 1 can be detected and the combustion amount can be instantaneously detected, the combustion amount detection device is not limited to the above combustion control, and the combustion amount in the furnace 1 of the fluidized bed incinerator can be instantaneously detected. Naturally, it can be effectively used for the control that requires the data detected in the above.

The number of brightness detection sensors 14-1 is not limited to one, but a plurality of brightness detection sensors 14-1 may be provided at appropriate locations in the furnace 1, and one of them may be one of the criteria, for example, one having the highest output. By making the selection, it becomes possible to detect the combustion amount with higher accuracy.

Further, in the above embodiment, an example in which the furnace pressure detecting means for detecting the pressure in the furnace is used in addition to the brightness detecting means for detecting the brightness in the furnace has been shown. The means for detecting the amount of combustion is not limited to this, but the means for detecting the oxygen concentration in the exhaust gas for detecting the oxygen concentration in the exhaust gas, and the properties, shape, volume and amount of the incineration material thrown into the furnace are detected. A detection means is provided, and the combustion amount in the furnace is determined by the greater of the brightness detection means, the oxygen concentration in the exhaust gas, and the detection means for detecting the property, shape, volume, and amount of the incinerator put into the furnace. Of course, it may be detected.

[0030]

As described above, according to the present invention, the following excellent effects can be obtained. (1) The incinerated matter is put into the fluidized bed, the incinerated matter is gasified in the fluidized bed, and the brightness in the furnace due to the flame generated by the combustion of the gas is detected. The amount of combustion can be measured instantaneously and accurately.

(2) In addition to the brightness detecting means for detecting the brightness in the furnace, a pressure detecting means for detecting the pressure in the furnace is provided.
By detecting the combustion amount in the furnace by the larger one of the outputs of the brightness detection means and the pressure detection means, for example, smoke is generated in the furnace and it becomes dark, and the brightness detection means detects the accurate combustion amount. Even if it is not possible, the pressure detecting means has a function of compensating for it.

[Brief description of drawings]

FIG. 1 is a diagram showing a relationship among a brightness L in a furnace, an oxygen concentration E in exhaust gas, and a furnace pressure P in a fluidized bed incinerator.

FIG. 2 is a diagram showing a schematic configuration of a fluidized bed incinerator in which a combustion amount detection device of the present invention is attached to perform combustion control.

FIG. 3 is a diagram showing a schematic configuration of a fluidized bed incinerator that performs combustion control by detecting the combustion amount of combustion products by detecting the pressure inside the furnace.

FIG. 4 is a diagram showing a configuration example of a combustion amount detection device of the present invention.

FIG. 5 is a diagram showing a configuration example of a combustion amount detection device of the present invention.

[Explanation of symbols]

 1 Furnace 2 Fluidized Bed 5 Piping 6 Air Chamber 7 Control Valve 8 Air Nozzle 9 Freeboard 11 Incinerator Input Hopper 12 Supply Feeder 13 Regulator 14-1 Brightness Detection Sensor 14-2 Pressure Detection Sensor 16 Piping 18 Secondary Air Delivery Inlet piping

Claims (7)

[Claims] 1. A combustion amount detecting device for detecting a combustion amount in a furnace of a fluidized bed furnace in which a fluidized medium is made to flow by air fed from a lower part of the fluidized bed to combust an incinerated substance put into the furnace. A combustion amount detection device for a fluidized bed furnace, comprising brightness detection means for detecting the brightness of the inside, and detecting the combustion quantity of the incinerator in the furnace from the output of the brightness detection means. 2. The combustion amount detecting device for a fluidized bed furnace according to claim 1, wherein the brightness detecting means is provided at a position overlooking the entire cross section of the furnace. 3. The combustion amount detecting device for a fluidized bed furnace according to claim 1, wherein the brightness detecting means is provided at a position that is not affected by the brightness due to the fluid medium or the furnace wall. 4. The combustion amount detecting apparatus for a fluidized bed furnace according to claim 1, wherein the brightness detecting means furnace is provided at or near the top of the furnace. 5. The combustion amount detecting device for a fluidized bed furnace according to claim 1, wherein the brightness detecting means is provided above a secondary air blowing position. 6. A combustion amount detecting device for detecting a combustion amount in a furnace of a fluidized bed furnace in which a fluidized medium is made to flow by air fed from a lower part of the fluidized bed to combust an incinerated substance put in the furnace. The brightness detection means for detecting the brightness in the interior and the detection means for detecting the oxygen concentration in the exhaust gas, the pressure in the furnace, and the property, shape, volume and amount of the incineration material thrown into the furnace are provided. And a detection means for detecting the oxygen concentration in the exhaust gas, the pressure in the furnace, and the property, shape, volume and amount of the incinerator that is put into the furnace, whichever is larger. Combustion amount detection device for fluidized bed furnace. 7. Any one of claims 1 to 6
A combustion control device for a fluidized bed furnace, wherein the output of the combustion amount detection device according to item 1 is used as a control signal for the combustion control device for the fluidized bed furnace.