JP2003266042A - Control method of ash heat dechlorination equipment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a control method for an ash heating and dechlorination treatment apparatus capable of successively setting an operation target temperature optimum to the thermal decomposition of ash to be treated so as to follow the composition or properties of ash to be treated regardless of a laboratory test and capable of efficiently heating and decomposing dioxins in ash to be treated while avoiding the generation of a granulation and adhesion phenomenon. <P>SOLUTION: In the ash heating and dechlorination treatment apparatus 1 having a heater 13 and an ash cooler 15, a temperature rise is controlled after the start of operation and a control target temperature Ts is set on the basis of the detected temperature Tm of ash A2 detected when the granulation of ash on the downstream side of the outlet of the heater 13 is generated. When the granulation of ash is not generated and the detected temperature Tm reaches an operation upper limit temperature Ta, the operation upper limit temperature Ta is set as the control target temperature Ts to perform control so that the detected temperature Tm keeps the control target temperature Ts. <P>COPYRIGHT: (C)2003,JPO

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 an incineration ash treatment apparatus, and more particularly to an organic chlorine compound such as dioxins contained in fly ash and bottom ash when incinerating municipal solid waste, industrial waste and the like. The present invention relates to a method of controlling an ash heating dechlorination apparatus for decomposing and detoxifying ash.

[0002]

2. Description of the Related Art Fly ash (dust collecting ash) and furnace bottom ash (incineration ash) discharged from an incinerator that incinerates municipal solid waste and industrial waste, etc., contains organic chlorinated compounds harmful to the human body, such as , P
CDD (polychlorinated dibenzodioxin), PCDF
Dioxins such as (polychlorinated dibenzofuran) and Co-PCB (coplana-PCB) are contained, and are known to pollute the environment.

As one of the systems for detoxifying organic chlorine compounds such as dioxins in the fly ash and the bottom ash,
There is an ash heating dechlorination treatment system 1 as shown in FIG. 1 proposed in JP 2001-25735 A and the like.
This system 1 supplies treated ash A1 such as fly ash (dust collected ash) and furnace bottom ash (incinerated ash) collected by a dust collector for treating exhaust gas of an incinerator to a supply hopper 11, and It is supplied to the heating device 13 by a fixed amount feeder 12 provided below the supply hopper 11.

The ash A1 to be treated is heated while being supplied with air F1 for drying and combustion of unburned components by the pushing blower 19 while passing through the heating device 13 for about 3 to 10 minutes. Is vaporized and the temperature is raised to a temperature higher than the thermal decomposition temperature of dioxins.

[0005] Then, due to the catalytic action of the metal contained in the ash A1 to be treated, reactions such as removing chlorine of dioxins and breaking oxygen bridges occur, and dioxins are decomposed and rendered harmless.

The detoxified high-temperature treated ash A2 is separated from the exhaust gas G1 by the discharge device 14 and discharged to the ash cooler 15 in order to prevent recombination with a part of the decomposition gas G. In this cooling device 15, dioxins are rapidly cooled with cooling water W so as not to be re-synthesized into low-temperature treated ash A3, which is then subjected to chemical treatment and solidification treatment and finally disposed.

On the other hand, the exhaust gas G separated by the exhaust device 14
1 is diluted with the air F2 of the forced blower 19 and sent to the dust collector 16, and becomes purified gas G4 via the activated carbon adsorption tower 17 and the suction blower 18, and is sent to an incinerator (not shown). Further, the fly ash Aa collected by the dust collector 16 is supplied to the supply hopper 11 and again subjected to thermal decomposition treatment.

In this heating device 13, decomposition and re-synthesis of organic chlorine compounds such as dioxins are remarkably accelerated by temperature, and there are problems of ash granulation and adhesion, heating efficiency and high temperature corrosion. Ash A1 heating device 13
Internal temperature control has become very important.

Therefore, the heating means of the heating device 13 is temperature-controlled so that it is heated to 410 ° C. or higher in order to decompose the dioxins in the ash by heating. Temperature Tm of treated ash A2 after
And the output of the heating means based on this temperature Tm,
That is, the electric power of the heat transfer heater, the amount of fuel supplied to the combustion burner, the amount of air F1 supplied, the amount of ash A1 to be processed, and the like are automatically adjusted.

The treatment temperature in the heating device 13 is preferably high in order to decompose the dioxin, and for ordinary ash A1 to be treated, the ash temperature Tm at the outlet is about 450 ° C. It is a normal operating temperature and is controlled to maintain this temperature.

[0011]

However, depending on the type of ash to be treated, the ash may adhere to each other to form particles or the ash to be treated may be heated in a heating device at a temperature range lower than 450 ° C., for example, 410 ° C. A granulation adhesion phenomenon such as adhesion to the heat exchange section occurs.

When this granulation adhesion phenomenon occurs, the heating efficiency decreases, the removal rate of dioxins and the like deteriorates,
In the worst case, the heating device is clogged, so it is necessary to change the operation target temperature depending on the composition and properties of the ash to be treated, and it is necessary to obtain the operation target temperature for each ash to be treated.

In the prior art, this operation target temperature was determined by a lab test of the ash to be treated before the operation of treating the ash to be treated and the result thereof. Therefore, a lab test before operation is indispensable.In addition, if the composition and properties of the treated ash do not change and are almost constant, it is effective to set the operation target temperature by a lab test. When the composition and properties of the ash to be treated change, it is difficult to make the operation target temperature correspond to an appropriate temperature, and there is a problem that proper operation control cannot be performed.

The present invention has been made to solve the above-mentioned problems, and its purpose is not to rely on laboratory tests.
By following the composition and properties of the ash to be treated, the optimum operating target temperature for the thermal decomposition of the ash to be treated can be sequentially set, and while avoiding the occurrence of granulation adhesion phenomena, dioxins in the ash to be treated can be efficiently processed. An object of the present invention is to provide a method of controlling an ash heating dechlorination treatment device capable of thermally decomposing ash.

[0015]

A method for controlling an ash heating dechlorination treatment apparatus for achieving the above object is a heating apparatus for heating ash to be treated to perform dechlorination treatment, and In an ash heating dechlorination treatment device having an ash cooler for cooling the discharged ash, and controlling the heat treatment temperature in the heating device based on the detected temperature of the ash on the outlet side of the heating device, While detecting the granulation state of ash on the downstream side from the outlet of the heating device, perform the temperature rise control after the start of operation,
When ash granulation occurs before reaching the predetermined operating upper limit temperature, the temperature obtained by subtracting the predetermined first correction temperature from the detected temperature at the time of occurrence is set as the control target temperature, and ash granulation does not occur. When the operating upper limit temperature is reached, the control target temperature is set as the operating upper limit temperature, and the temperature is controlled so that the detected temperature becomes the control target temperature.

According to the control method of the ash heating dechlorination apparatus, the ash granulation state is detected in the actual processing operation, and the ash detection temperature when the ash granulation occurs is used as a reference. Since the control target temperature is set in accordance with the above, the optimum control target temperature that can avoid the granulation adhesion phenomenon in the heating device and efficiently perform the dechlorination reaction regardless of the laboratory test of the ash to be treated Can be set.

The first correction temperature is subtracted in order to correct the time delay between the temperature rising state of the superheater and the granulation detection to obtain a more optimal control target temperature. This first correction temperature is usually set to a value of about 0 ° C to 20 ° C.

The temperature of the ash on the outlet side of this heating device is measured by
This is performed by a temperature detector arranged in the discharge device on the outlet side of the heating device.As this temperature detector, a thermocouple, a resistance temperature detector,
An infrared radiation thermometer or the like can be used.

Further, since the ash to be treated is heated while rotating in the heating device, the ash granules discharged from the heating device have an adzuki bean shape or a bales shape, for example, a diameter of 5 m.
About mφ to 7 mmφ and a length of about 10 mm to 15 mm are set as predetermined granulation standards, and when the granulation standard is exceeded, it is determined that granulation has occurred.

As a method of detecting the granulated state, a part of the ash discharged from the heating device, the ash cooler or the like is sieved for a predetermined time, and the weight of the granulated material on the sieve is detected to detect the weight of the granules above the predetermined level. There are a method of determining that the granulation occurs when the weight becomes heavy, a method of image processing, and the like. The ash granulation state may be detected at the outlet of the heating device or the outlet of the cooler. The temperature of ash on the outlet side of the heating device is about 410 ° C to 460 ° C, while the temperature of ash on the outlet side of the ash cooler is 10 ° C.
Since the temperature is about 0 ° C., it is more advantageous to provide the granulation detecting means at the outlet of the ash cooler in terms of heat countermeasures.

The operating upper limit temperature is a temperature at which the dechlorination reaction proceeds efficiently, and is usually 440 ° C to 460 ° C. When the operating upper limit temperature is exceeded, the thermal energy required for heating increases without the effect of promoting the dechlorination reaction, resulting in poor thermal efficiency.

Regarding the resetting of the control target temperature at the time of starting the granulation, when ash granulation occurs when the detected temperature is controlled so as to maintain the control target temperature, The temperature is controlled until the ash granulation does not occur or to the operating lower limit temperature, and the control target is added to the temperature obtained by adding a predetermined second correction temperature to the detected temperature when the ash granulation does not occur. Configured to update temperature.

By this control, the composition and properties of the ash to be treated are changed to detect the start of the occurrence of the granulation adhesion phenomenon, and the control target temperature is updated to a temperature at which the granulation adhesion phenomenon does not occur and heated. Since the treatment temperature can be lowered, it is possible to avoid granulation adhesion in the heating device. The second correction temperature is added in order to correct the time delay between the temperature rising state of the heating device and the granulation detection to obtain a more optimal control target temperature. Corrected temperature is usually 0 ° C to 20 ° C
It is set to some value.

Regarding the resetting of the control target temperature when granulation does not occur, when the detected temperature is controlled so as to maintain the control target temperature, the period during which ash granulation does not occur is When the predetermined time is exceeded, temperature increase control is performed, and when ash granulation occurs before reaching the operating upper limit temperature, the temperature is obtained by subtracting the first correction temperature from the detected temperature at this time. The control target temperature is updated, and when the operating upper limit temperature is reached without ash granulation, the control target temperature is updated to the operating upper limit temperature.

In the temperature rising control for starting the operation, an alarm is issued when it is detected that ash granulation has occurred before the detected temperature reaches the operation upper limit temperature,
In the temperature decrease control, an alarm is generated when the detected temperature reaches the operation lower limit temperature without eliminating the generation of ash granulation. With these controls,
It is possible to avoid the treatment operation below the operation lower limit temperature at which the dechlorination reaction remarkably decreases.

The predetermined time during which the continuous operation is performed before starting the temperature raising control is a time determined by the balance between the change in composition and properties of the ash to be supplied to the heating device and the supply amount.

With this configuration, the control target temperature can be updated to a temperature at which dechlorination can be performed more efficiently even when the composition and properties of the ash to be treated change and the granulation start temperature changes.

Then, the temperature raising rate in the temperature raising control is set to 3 ° C.
/ Min to 6 ° C / min, the operating upper limit temperature is set to 440 ° C to 460 ° C, preferably 450 ° C, and the first correction temperature is set to 0 ° C to 20 ° C. 1 ° C / min to 2 ° C / min
In addition, it is preferable that the lower limit temperature of operation is 400 ° C. to 420 ° C., preferably 410 ° C., and the second correction temperature is 0 ° C. to 20 ° C.

If the temperature lowering rate is lower than 1 ° C./min, the granulation adhesion phenomenon is extended in the heating device, and problems such as poor heat transfer and blockage occur. This is because it becomes difficult to detect the target temperature, and the operation lower limit temperature is set to 400 ° C to 420 ° C because the dechlorination reaction is significantly reduced at a temperature lower than 400 ° C.

[0030]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of a method for controlling an ash heating dechlorination apparatus according to the present invention will be described below with reference to the drawings.

First, the structure of an ash heating dechlorination apparatus for carrying out the control method of the present invention will be described.

As shown in FIG. 1, the ash heating dechlorination apparatus 1 comprises an externally heated multi-cylinder type rotary kiln heating apparatus 13 and an ash cooler 15.

In this ash heating dechlorination treatment apparatus 1, the ash A1 to be treated such as fly ash and bottom ash collected by the dust collector for treating the exhaust gas of the incinerator is supplied to the supply hopper 11 and the lower part thereof. It is supplied to the heating device 13 by means of the constant quantity feeder 12 provided in the.

The ash A1 to be treated in the heating device 13 is supplied with the air F1 for drying and combustion of unburned components, which is supplied by the push blower 19 and heated by the air heater 20.
It passes through a rotating heating tube in a thin layer of several cm, is stirred by a stirring plate and is heated to about 400 ° C. to 550 ° C. substantially uniformly, and is delivered to the outlet side in about 5 minutes to 10 minutes.

In the heating device 13, the ash A1 to be treated evaporates water and 400 to 550 ° C. of dioxins.
The temperature is raised above the thermal decomposition temperature of. Due to the catalytic action of the metal contained, chlorine of dioxins is removed,
Oxygen bridges are cleaved to cause reactions, and dioxins are decomposed and rendered harmless.

The ash A1 to be treated is subjected to the dechlorination treatment by this thermal decomposition treatment to become the treated ash A2 and the exhaust gas G1, and the discharging device 14 provided at the outlet portion of the heating device 13.
Are separated and discharged.

The treated ash A2 discharged at this high temperature is sent to the ash cooler 15, and the discharged treated ash A2 is discharged.
Re-synthesizes dioxins at temperatures near 300 ° C, so the ash cooler 1 should prevent dioxins from being re-synthesized.
5 within 5 minutes, preferably 100 ° C. within 5 minutes with cooling water W
The ash A3 is rapidly cooled to a temperature (preferably 80 ° C.) or less, and the treated ash A3 close to room temperature is discharged. This treated ash A3
Are treated with chemicals or solidified and finally disposed.

On the other hand, the exhaust gas G separated by the exhaust device 14
1 is diluted with the air F2 of the forced blower 19 and sent to the dust collector 16 to collect dust, and then sent to the activated carbon adsorption tower 17 to be purified gas G4, which is incinerated (not shown) via the suction blower 18. It is sent to a furnace.

Further, the fly ash Aa collected by the dust collector 16 is supplied to the supply hopper 11 and is again heat decomposed.

In the ash heating dechlorination apparatus 1 of this structure, a temperature detector 31 for measuring the temperature Tm of the ash after the heat treatment is provided in the discharge device 14 on the outlet side of the heating device 13. The temperature detector 31 includes a thermocouple, a resistance temperature detector,
A temperature detector such as an infrared radiation thermometer can be used.

Then, the temperature control in the control operation of the ash heating dechlorination apparatus 1, particularly the constant temperature control operation, the temperature increase control operation, the temperature decrease control operation of the heating apparatus 13 is performed by the discharge apparatus 14.
The temperature Tm of the ash-treated ash A2 after the heat treatment is measured with, and the output of the heating means of the heating device 13, that is, the electric power of the heat transfer heater and the fuel supply amount to the combustion burner are automatically adjusted based on the detected temperature Tm. Or the amount of ash A1 to be treated and the amount of air F2 supplied to the heating device 13 are automatically adjusted.

Next, ash heating dechlorination apparatus 1 of the present invention
An example of the control method will be described with reference to the flowchart of FIG.

In this control method, the detected temperature Tm of ash (processed ash) detected by the temperature detector 31 provided in the discharge device 14 at the outlet of the heating device 13 is used as the control temperature (operating temperature) of the heating device 13, etc. Performs operation control, especially temperature control.

When the operation of the ash heating dechlorination apparatus 1 is started, the flow of FIG. 2 is started, and step S11
The temperature rise control operation is performed for a predetermined time. By this temperature increase control operation, the amount of heat supplied to the heating means of the heating device is increased to raise the ash detection temperature Tm, that is, the control temperature Tm.

In the next step S12, the presence or absence of granulation is checked by the granulation detecting means. When ash granulation occurs, that is, when the detected ash granulation state exceeds a predetermined granulation standard, it is determined that the granulation start temperature has occurred and granulation has occurred, and the step The detected temperature Tm is checked in S13, and if the detected temperature Tm is lower than the operation lower limit temperature Tb,
An alarm is generated in step S15, and then step S1
Return to the temperature rise control operation of No. 1 or step S4
It goes to 0 and finishes driving. In step S13, the detected temperature T
If m is higher than the operation lower limit temperature Tb, that is, if ash granulation occurs before reaching the operation upper limit temperature Ta, the process proceeds to step 14 and a predetermined first correction is made from the ash detection temperature Tm detected at that time. The temperature obtained by subtracting the temperature ΔT1 (Tm-Δ
The control target temperature Ts is set to T1), and the process goes to step S20.

If ash granulation does not occur in step S12, the detected temperature Tm is checked in step S16. If the detected temperature Tm is lower than the operation upper limit temperature Ta, the temperature raising control operation in step S11 is performed. Returning to step S17, if the temperature is equal to or higher than the operation upper limit temperature Ta, that is, if the operation upper limit temperature Ta is reached without ash granulation, the control target temperature Ts = Ta is set in step S17. Then, go to step S20.

In step S20, the time counter tc for measuring the operation elapsed time of the constant temperature control operation is reset, and in the next step S21, the constant temperature control operation is performed for a predetermined time Δt. In this constant temperature control operation, the detected temperature Tm is controlled so as to maintain the control target temperature Ts, and the operation time is counted at this time.

Step S22 after this step S21
Then, check for the occurrence of granulation, and if there is no occurrence,
In step S23, the elapsed time tc is checked. When the elapsed time tc is checked in step S23 and the predetermined operation time ta has not elapsed, the process returns to step S21. If the predetermined operation time ta has elapsed, step S
Return to 11.

That is, the detected temperature Tm is the control target temperature Ts.
If the period during which ash granulation does not occur exceeds the predetermined time ta during the control so that the temperature is controlled to be maintained, the process returns to step S11 to perform the temperature increase control to set the operation upper limit temperature Ta.
If ash granulation occurs before reaching step S1, step S1
4, the predetermined first correction temperature ΔT from the detected temperature Tm at this time
The control target temperature Ts is added to the temperature (Tm-ΔT1)
When the operating upper limit temperature Ta is reached without generating ash granulation, the control target temperature Ts is updated to the operating upper limit temperature Ta in step S17.

In step S22, the presence or absence of granulation is checked. If granulation occurs, step S30
In step S3, the temperature reduction control operation is performed for a predetermined time.
1. Check for the occurrence of granulation. If the occurrence of granulation disappears, the temperature obtained by adding a predetermined second correction temperature ΔT2 to the detected temperature Tm at that time in step S32 (Tm + ΔT2)
To the control target temperature Ts.

In step S31, the presence or absence of granulation is checked. If granulation occurs, the detected temperature Tm is checked in step S33. If it is higher than the operation lower limit temperature Tb, the temperature is lowered in step S30. Return to control operation. If it is below the operation lower limit temperature Tb, an alarm is issued in step S34. After this alarm is issued, the control target temperature Ts is updated to the operation lower limit temperature Tb and the operation returns to step S20 to continue the operation, or the operation goes to step S40 to end the operation.

In step S34, the control target temperature T
s is set as the operation lower limit temperature Tb to prevent the detected temperature Tm from falling below the control target temperature Ts during operation.

That is, the detected temperature Tm is the control target temperature Ts.
When ash granulation occurs while controlling so as to maintain the temperature, temperature control is performed in step S30, and when ash granulation does not occur, a predetermined second correction is made to the detected temperature Tm at that time. To the temperature (Tm + ΔT2) that is obtained by adding the temperature ΔT2,
The control target temperature Ts is updated. In the temperature drop control, if the detected temperature Tm reaches the operation lower limit temperature Tb with ash granulation still occurring, an alarm is issued in step S34.

When the operation is completed, step S4
At 0, an operation end interrupt is generated, and after the operation end control of step S50, the flow is stopped and ended.

In these controls, the operating upper limit temperature Ta is 440 ° C. to 460 ° C., preferably 450
C, the operating lower limit temperature Tb is 400 ° C to 420 ° C, preferably 410 ° C, the first corrected temperature ΔT1 is 0 ° C to 20 ° C, and the second corrected temperature is 0 ° C to 20 ° C. This operation upper limit temperature Ta is the temperature at which the dechlorination reaction proceeds efficiently. Above this temperature, the thermal energy required for heating increases without the effect of promoting the dechlorination reaction, resulting in poor thermal efficiency. Further, when the temperature becomes lower than the operation lower limit temperature Tb, the dechlorination reaction becomes slow and the dechlorination becomes insufficient.

The temperature raising rate in the temperature raising control in step S11 is preferably 3 ° C./min to 6 ° C./min, and the temperature lowering rate in the temperature lowering control in step S30 is preferably 1 ° C./min to 2 ° C./min. .

The temperature control shown in FIG. 3 can be performed by the control method of the ash heating dechlorination apparatus 1 described above.

As shown in FIG. 3 (a), when ash granulation occurs before reaching a predetermined operating upper limit temperature Ta (C1), a predetermined first correction is made from the detected temperature Tm1 at this time. When the temperature control is performed as shown by the solid line with the temperature Tm1-ΔT1 obtained by subtracting the temperature ΔT1 as the control target temperature Ts, and when the operating upper limit temperature Ta is reached without ash granulation (C2).
In the above, temperature control is performed as indicated by the dotted line in which the detected temperature Tm becomes the control target temperature Ts with the control target temperature Ts as the operation upper limit temperature Ta.

Further, as shown in FIG. 3B, when ash granulation occurs when the detected temperature Tm is controlled so as to maintain the control target temperature Ts, the ash granulation is not performed. When the ash granulation does not occur (C3) when the temperature is controlled to decrease until it does not occur or to the operating lower limit temperature Tb,
The control target temperature Ts is updated to the temperature Tm2 + ΔT2 obtained by adding the predetermined second correction temperature ΔT2 to the detected temperature Tm2 at that time, and the temperature control shown by the solid line for maintaining this control target temperature Ts is performed. If the temperature is lowered to the operation lower limit temperature Tb while the ash granulation continues (C4), an alarm is issued.

Then, as shown in FIG. 3C, when the detected temperature Tm is controlled so as to maintain the control target temperature Ts, the period during which ash granulation does not occur exceeds a predetermined time ta. If the temperature rises, the temperature rise control is performed. In this temperature increase control, when ash granulation occurs before the operating upper limit temperature Ta is reached (C5), the control target is the temperature Tm3-ΔT1 obtained by subtracting the first correction temperature ΔT1 from the detected temperature Tm3 at this time. The temperature Ts is updated, and temperature control for maintaining this control target temperature Ts is performed. When the operating upper limit temperature Ta is reached without ash granulation (C6), the control target temperature Ts is updated to the operating upper limit temperature Ta, and temperature control is performed to maintain this control target temperature Ts. It

Next. A method for detecting the occurrence of ash granulation will be described.

In this ash granulated product, the ash to be treated is the heating device 1
Since it is heated while rotating in 3, it has an adzuki bean shape or a bales shape. For example, a diameter of about 5 mmφ to 7 mmφ and a length of about 10 mm to 15 mm are used as the predetermined granulation criteria. When it is above, it is judged that the generation of granulation has started.

As means for detecting the granulated state and occurrence of granulation, there are means as shown in FIGS. 4 to 9, for example.

In the sieve type sensor shown in FIG. 4, the ash A is supplied to only one side of the sieve 41 for a predetermined time and sieved to obtain the sieve 4
The weight of the granulated material Ab accumulated on the No. 1 is detected, and when the weight exceeds a predetermined value, the sieve 41 is rotated by the weight of the granulated material Ab, and the sieve 41 is provided on the rotating shaft 42 that rotatably supports the sieve 41. The protrusion 44 turns on the proximity switch 45, and when the proximity switch 45 is turned on, the start of granulation is determined. After half a rotation, the initial state is reached, and the detection of the granulated material Ab is continued.

In the impact type sensor shown in FIG. 5, the impact force of the granulated material Ab on the rotating plate 45 is detected,
The rotating plate rotates due to a collision force of a predetermined value or more, and the rotating plate 45
The protrusion 44 provided on the rotary shaft 42 that rotatably supports the proximity switch 45 turns on the proximity switch 45, and the proximity switch 45 turns on.
Determine when granulation starts. In addition, after half a rotation, the initial state is reached, and the detection of the granulated material Ab is continued. Alternatively, the rotary plate may be supported by a rotary spring, the tilt of the rotary plate may be detected by a collision force, and the switch may be turned on when a predetermined tilt is exceeded.

In the rotary vane type sensor shown in FIG. 6,
A disk 47 that rotates with the rotating shaft 42 due to a change in the number of rotations due to the collision force of the granulated material Ab that hits the rotary blades 46, and the disk 47.
The number of rotations is detected by the sensor 48 for detecting the rotation, and when the amount of change in the number of rotations becomes larger than a predetermined amount of change, it is determined that granulation has started.

In the method using the image processing apparatus shown in FIG. 7, the discharging device 14 and the ash cooler 15 of the heating device 13 are used.
The size of the ash passing through the pipe passage provided between the two is monitored, and when the particle size exceeds a predetermined size, it is judged that granulation has started. To detect this particle size, a pipe is provided with a window, light is emitted from one light 51, the shadow of passing particles is photographed by the camera 52 on the opposite side, and this photographed image is sent to an image processing device. The particle size is detected by image processing.

Further, in the method using microwaves shown in FIG. 8, as shown in FIG. 8A, a predetermined amount is provided in the pipe passage provided between the discharge device 14 of the heating device 13 and the ash cooler 15. Sieve 54 and microwave switch 53, which rotate half a time
a and 53b are provided, and the granules Ab deposited on the sieve 54 are detected because the granules Ab having a particle size of the ash A that is equal to or larger than a predetermined size cannot pass through the sieve 54. Judge as the start of granulation. This microwave switch includes a wave transmitter 53a that generates microwaves and a wave receiver 5 that receives microwaves.
3b is a switch which is installed facing each other and detects that the microwave is attenuated due to a certain amount of the measured substance (here, the granulated substance Ab) being accumulated between the transmitting and receiving waves and outputs an output signal. Alternatively, as shown in FIG. 8B, only the microwave switches 53a and 53b are provided without providing the sieve 54, and the size of the ash A and the granulated substance Ab passing through the pipe passage and the attenuation and output of the microwaves. The start of granulation is judged from the relationship with the signal.

Further, in the contact type sensor shown in FIG. 9, the arm 54 sandwiches the granulated material Ab in the ash flow, and the sensor detects whether or not the granulated material Ab is sandwiched. In the judgment of the start of granulation, a certain width (about 1 mm-
10 mm), and when the width of the granulated material Ab hangs, it is determined that the granulation has started.

In addition, there is also a method of detecting the size of particles passing through by providing optical sensors at two points at right angles on the pipe.

[0071]

As is apparent from the above description, the ash heating dechlorination treatment apparatus according to the present invention has the following effects.

For the ash to be treated, the control target temperature is operated at the granulation start temperature or the operation upper limit temperature between the operation lower limit temperature and the operation upper limit temperature while observing the relationship between the treatment temperature and the granulation state. Therefore, the ash to be treated can be treated in a state in which the efficiency of the dechlorination reaction is good while avoiding the granulation adhesion phenomenon that causes a decrease in the thermal efficiency, a decrease in the heat transfer efficiency of the heating device, and a clogging.

That is, when a granulated product begins to be formed during the temperature rise after the start of operation, the temperature rise control is stopped and the temperature below the granulation start temperature is set as the control target temperature to dechlorinate the ash to be treated. When the granulation is started during the treatment operation, the temperature is controlled to be lowered, and the temperature below the granulation start temperature at that time is set as the control target temperature to dechlorinate the ash to be treated. You can Further, if the time during which the granulation is not started during the processing operation continues for a predetermined time, the temperature rise is controlled, the granulation start temperature at that time is detected, and the temperature below this granulation start temperature is controlled to the target temperature. Thus, the ash to be treated can be efficiently dechlorinated.

Therefore, the operation target temperature can be easily determined without using a laboratory test, and the ash to be heated can be heated by following the composition and properties of the ash to be treated regardless of the composition and properties of the ash to be treated. Since the optimum operation target temperature for decomposition can be sequentially set, the dioxins in the ash to be treated can be efficiently thermally decomposed while avoiding the occurrence of the granulation adhesion phenomenon.

[Brief description of drawings]

FIG. 1 is a system diagram showing an ash heating dechlorination apparatus according to an embodiment of the present invention.

FIG. 2 is a flowchart showing an example of a control method of the ash heating dechlorination treatment apparatus according to the embodiment of the present invention.

3 is a time-series diagram showing a control example by the control method of FIG. 2, (a) is a diagram showing a temperature rising control at the start, and (b) is a temperature control at the time when granulation starts to occur. In the figure, (c) is a diagram showing temperature control when a predetermined period of time has passed without occurrence of granulation.

FIG. 4 is an explanatory diagram of a limit switch type sensor that detects a granulation state.

FIG. 5 is an explanatory diagram of an impact type sensor that detects a granulation state.

FIG. 6 is an explanatory diagram of a rotary wing type sensor that detects a granulation state.

FIG. 7 is an explanatory diagram of image processing for detecting a granulation state.

8A and 8B are explanatory views of a microwave utilization sensor for detecting a granulation state, where FIG. 8A is a deposition type and FIG. 8B is a passage type.

FIG. 9 is an explanatory view of a contact type sensor for detecting a granulation state,
(A) is a figure which shows pinching, (b) is a figure which shows a passing state, (c) is a figure which shows the pinching state.

[Explanation of symbols]

1 Ash heating dechlorination equipment 13 Heating device 15 Ash cooler A1 ash to be treated A2 ash (treated ash) A3 ash (cooling ash) Ta operating upper limit temperature Tb operating lower limit temperature Ts control target temperature Tm ash detection temperature ΔT1 predetermined first correction temperature ΔT2 predetermined first correction temperature

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) F27D 15/02 F27D 21/00 A 19/00 B09B 3/00 303L 21/00 ZAB (72) Inventor Takasuka Gentaro 1 Hachiman Kaigan Dori, Ichihara, Chiba Mitsui Engineering & Shipbuilding Co., Ltd. Chiba Works F Term (reference) 3K061 AA07 AB02 AC03 BA02 BA08 CA07 FA03 FA23 NA01 3K062 AA07 AB02 AC03 BA02 BB02 CA00 CA06 CA08 CB03 DA01 DA31 DB12 4D004 AA36 AB06 AB07 CA07 CA32 CB09 DA01 DA02 DA03 DA06 DA11 DA20 4K056 AA00 BA02 BB05 CA20 FA04 FA11 4K063 AA01 AA18 BA13 CA02 CA03 HA61 HA65

Claims (6)

[Claims] 1. A ash cooler that heats ash to be treated to perform dechlorination treatment and an ash cooler that cools ash discharged from the heating device. In the ash heating dechlorination treatment device that controls the heat treatment temperature in the heating device based on the detected temperature, while detecting the ash granulation state on the downstream side from the outlet of the heating device, temperature increase control after the start of operation When ash granulation occurs before reaching the predetermined operating upper limit temperature, the temperature obtained by subtracting the predetermined first correction temperature from the detected temperature at the time of occurrence is set as the control target temperature, and the ash granulation is performed. A method for controlling an ash heating dechlorination treatment apparatus, wherein when the operating upper limit temperature is reached without generating the temperature, the control target temperature is set as the operating upper limit temperature, and the temperature is controlled so that the detected temperature becomes the control target temperature. 2. When ash granulation occurs while the detected temperature is controlled to maintain the control target temperature, the temperature is lowered to the ash lower limit temperature or until ash granulation does not occur. The ash heating dechlorination apparatus according to claim 1, wherein the control target temperature is updated to a temperature obtained by adding a predetermined second correction temperature to the detected temperature when ash granulation does not occur. Control method. 3. When the detected temperature is controlled so as to maintain the control target temperature, and when the period during which ash granulation does not occur exceeds a predetermined time, temperature increase control is performed, When ash granulation occurs before the operating upper limit temperature is reached, the control target temperature is updated to a temperature obtained by subtracting the first correction temperature from the detected temperature at this time, and ash granulation does not occur. The control target temperature is updated to the operation upper limit temperature when the operation upper limit temperature is reached.
A method for controlling an ash heating dechlorination treatment apparatus according to claim 1. 4. An alarm is generated when it is detected that ash granulation has occurred before the detected temperature reaches the operation lower limit temperature in the temperature increase control for starting the operation.
The method for controlling the ash heating dechlorination apparatus according to any one of 1. 5. An alarm is generated when the detected temperature reaches an operation lower limit temperature without eliminating the generation of ash granulation in the temperature reduction control.
Item 6. A method for controlling an ash heating dechlorination treatment apparatus according to item. 6. The temperature raising rate in the temperature raising control is 3 ° C. /
min to 6 ° C./min, the temperature lowering rate in the temperature lowering control is 1 ° C./min to 2 ° C./min, the operation upper limit temperature is 440 ° C. to 460 ° C., and the operation lower limit temperature is 4
00 ° C to 420 ° C, and the first correction temperature is 0 ° C to 20 ° C.
C. and the second correction temperature is 0 to 20.degree.
6. The method for controlling the ash heating dechlorination treatment apparatus according to any one of 5 above.