JPH0585809B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an automatic combustion control device for a garbage incinerator used in a municipal waste incinerator or an industrial waste incinerator using a stepped stoker.

(Prior art) Step-type stokers are widely used in municipal waste incinerators and industrial waste incinerators, and the material of the grate of these stokers is generally high chromium steel (for example, 25
%Cr-1%Ni, etc.) are used. This material will not burn out in the air even at temperatures between 1050°C and 1100°C, but garbage may contain Cl and S, and when burned, these become HCl and SO ₂ and emit so-called high-temperature gas. May cause corrosion. These corrosive gases cause slow corrosion when used alone, but when chlorides such as NaCl and KCl are contained in the incineration ash, severe corrosion occurs at relatively low temperatures due to co-corrosion with low melting point substances. known to occur. In other words, corrosion occurs rapidly in ordinary steel from around 300℃,
Even high chromium steel undergoes rapid corrosion at temperatures above 400℃.

In this way, the grate of the garbage incinerator stoker is
There is always a risk of being attacked by high-temperature corrosion, and it is no longer possible to rely solely on the material of the grate as a measure to prevent high-temperature corrosion.

Thus, the stoker grate is cooled by the combustion air introduced from below, and even if combustion occurs on the surface of the grate, the temperature of the grate itself is kept at a relatively low temperature. That is, the life of the grate can be maintained by balancing the amount of heating from the top surface and the amount of cooling by combustion air from below.

In this way, the temperature of the grate can be varied by increasing or decreasing the amount of combustion air, and it can be maintained at a constant temperature by controlling the amount of air.

FIG. 6 is a schematic vertical cross-sectional view of a conventional garbage incinerator, which is composed of a garbage hopper 30, a garbage constant supply feeder 31, a drying stoker 32, a combustion stoker 33, a combustion stoker 34, etc. The garbage put into the garbage hopper 30 is transferred to the drying stoker 3 by the supply feeder 31.
2, each stalker 32, 33, 34
The ash is sequentially dried and burned at the top, and is discharged from the discharge chute 35 as ash.

Combustion air is sent to hoppers 37 disposed below each stoker 32, 33, and 34 through an air duct 36, and is ignited through the gap formed between the movable grate 38 and the fixed grate 39. Each stoker 32,
The lower surfaces of 33 and 34 are cooled to prevent high temperature corrosion.

Further, the combustion gas generated by combustion passes from the combustion chamber to a boiler (not shown) connected thereto, passes through a dust collector, etc., and is discharged to the outside from a chimney.

(Problem to be Solved by the Invention) By the way, in garbage incinerators, it is necessary to control the temperature of the stoker grate below a certain level to prevent high-temperature corrosion. Embed a thermocouple on the underside of the fixed grate,
The temperature of the grate was continuously measured by a temperature meter, and based on this, the operator could adjust the combustion condition by adjusting the amount of combustion air and at the same time prevent the temperature of the grate from rising.

However, there is a problem in that manual control so that both the combustion state and the grate temperature are optimal requires considerable skill.

Furthermore, since thermocouples are used, it is practically difficult to measure all of the large number of fire grates, and thermocouples are only provided at the top, middle, and bottom of the stoker. Therefore, it is not possible to accurately measure the grate temperature,
In some cases, it was not possible to control the amount of air to the optimum level. As a result, the grate sometimes suffered from high-temperature corrosion or failed to achieve good combustion.

On the other hand, in a waste incinerator, when the waste is of good quality, the main combustion zone on the stoker tends to move from above the combustion stoker to the drying stoker side, and when the waste is of bad quality, it moves from above the combustion stoker to the combustion stoker side. Try to move. At this time, if you do not increase the driving speed of the stoker with good quality garbage, the garbage on the stoker will turn into ash, and on the other hand, with bad garbage, if you do not slow down the driving speed of the stoker, unburned materials will be mixed with the ash. It will be discharged from the discharge chute. If this adjustment of the driving speed of the stoker is not done in correlation with the adjustment of the amount of combustion air sent below the stoker, the amount of combustion of waste on the stoker will change, and the amount of steam generated by the boiler will be controlled. It also becomes difficult.

Conventionally, the amount of combustion air and the drive speed of the stoker were adjusted by an operator by monitoring the movement of the main combustion zone above the stoker using an industrial television camera 40; This was a problem because the operator relied heavily on intuition, and the adjustment based on intuition was not necessarily optimal, and the adjustment also differed depending on the experience of each operator.

Recently, these adjustments have become automatic control, but it is difficult to automatically measure only the movement of the main combustion zone above the stoker, and it is difficult to completely automate the operation of a waste incinerator. It was difficult.

The present invention was devised to solve the above problems, and its purpose is to accurately and easily detect the temperature of the entire grate and the movement of the main combustion zone on the stoker, and to detect the temperature of the entire grate and the movement of the main combustion zone on the stoker. An object of the present invention is to provide an automatic combustion control device for a garbage incinerator that can provide protection and good combustion.

(Means for Solving the Problem) In order to achieve the above object, the automatic combustion control device for a garbage incinerator of the present invention includes an air supply device that supplies air below a plurality of sets of stokers, and a grate temperature measurement device that measures temperature changes across the grate and detects movement of the main combustion zone on the stoker;
A control device that controls the air supply device based on a detection signal from the grate temperature measuring device and adjusts the amount of air supplied to each stoker so that the temperature of all the grate is below the temperature that causes high-temperature corrosion. The grate temperature measuring device is connected to an infrared camera arranged below each stoker and connected to a control device for detecting temperature changes of the entire grate; It consists of a display that displays the overall temperature distribution.

Further, it is preferable that an exhaust gas circulation device for sending part of the exhaust gas in the flue below each stoker is connected to the control device, and the control device is configured to control the exhaust gas circulation device.

Furthermore, it is preferable that the stoker drive device of each stoker be connected to the control device so that the stoker drive device is controlled by the control device.

(Function) When the temperature of the entire grate of each stoker is detected by the infrared camera, this is image-processed by computer graphics and displayed as a contour curve or the like on the display. This allows the temperature of the entire grate and the movement of the main combustion zone above the stoker to be detected accurately and easily.

Then, when the grate temperature and the position of the main combustion zone are detected, the control device controls the air supply device based on this detection signal so that the amount of air supplied to each stoker is the optimal value. Adjust the air intake amount. As a result, the temperature of the grate can be adjusted to prevent high-temperature corrosion of the grate, and good combustion conditions can always be obtained.

In addition, if an exhaust gas circulation device is provided that can send a portion of the exhaust gas to the bottom of each stoker, and this is controlled by a control device based on the above detection signal, so that the exhaust gas is also sent to the bottom of the stoker. Combustion on the grate is suppressed, the temperature of the grate can be reliably lowered, the grate can be protected, and the generation of NOx can also be suppressed.

Furthermore, if the air supply device, exhaust gas circulation device, and stoker drive device are controlled by a control device, air and exhaust gas are sent below the stoker, and the stoker speed is adjusted, NOx generation can be prevented. In addition, the amount of steam generated by the boiler can be accurately controlled.

(Example) Hereinafter, an example of the present invention will be described in detail based on the drawings.

FIG. 1 is a schematic vertical cross-sectional view of a garbage incinerator using an automatic combustion control device according to the present invention, and the garbage incinerator includes a garbage hopper 1, a garbage constant supply feeder 2, a drying stoker 3, and a combustion stoker 4. , a combustion stoker 5, etc., and a boiler 6 is connected to the furnace wall of the waste incinerator.

The garbage put into the garbage hopper 1 is sent by the supply feeder 2 to a drying stoker 3 in a fixed amount, where it is dried, then sent to the combustion stoker 4 where it is combusted, and then left behind. The ash is deposited on the combustion stoker 5, burnt, and completely turned into ash, which is then discharged from the exhaust chute 7.

Furthermore, air for drying and combustion is fed into hoppers 9 disposed below each stoker 3, 4, and 5 by an air feeding device 8, and combustion gas is fed into the combustion chamber 1.
0, is discharged to the outside through a boiler 6, etc.

FIG. 2 is a schematic partial perspective view showing details of the step-type stoker, and the stoker includes a movable grate 1
1 and fixed grate 12 are arranged alternately in a stepwise manner,
Each fixed grate 12 is fixed to a fixed frame 13, and each movable grate 11 is attached to a movable frame 15 via a support 14, and a slide 1 supports the movable frame 15 and slides on the frame 16 in the front and back direction.
7 is connected to a stoker drive device 18 such as a hydraulic cylinder, and the movable grate 11 is moved over the fixed grate 12 by sliding the movable frame 15 in the front-rear direction at a constant pitch by the stoker drive device 18.
It is designed to move garbage by sliding back and forth.

In addition, air for drying and combustion is fed into the hopper 9 by the air feeding device 8, and is blown out from the gap between the fixed grate 12 and the movable grate 11 onto the upper surface of the grate 11, 12, thereby contributing to combustion. At the same time, Stalker 3,
4 and 5 are cooled.

The automatic combustion control device according to the present invention uses the grate temperature measuring device 19 to control each stoker 3, 4,
The temperature change of the entire grate 11, 12 of No. 5 is detected and visualized, and the air supply device 8 is controlled by the control device 20 based on the detection signal from the grate temperature measuring device 19. , 12 is adjusted so that the temperature of the stokers 3, 4, and 5 is below the temperature that causes high-temperature corrosion.

That is, the air feeding device 8 has the stoker 3,
Air ducts 21 connected to each of the hoppers 9 below 4 and 5, a forced air blower 22 connected to the air duct 21, a damper 23 interposed in each air duct 21, and a damper drive device for each damper 23. 24, etc., and the damper drive device 24 is controlled by the control device 20.

The grate temperature measuring device 19 includes a stoker 3,
Provided in each hopper 9 below 4 and 5, the grate 1
A control device 20 that detects temperature changes throughout 1 and 12
an infrared camera 25 connected to the grate 11,
It consists of a display 26 such as a cathode ray tube connected to a control device 20 capable of displaying the temperature distribution of the entire grate 12, and all the grate 11, 12 are arranged in a matrix shape of a plurality of grate in the vertical direction and a plurality of grate in the horizontal direction. The fire grates 11 and 12 are separated into
The overall temperature can be measured, image processed using computer graphics, and contour curves as shown in Figure 3 can be displayed on the display 26, and the temperature can also be measured by color-coded display. There is.

Thereby, the temperature of all the grates 11 and 12 and the movement of the main combustion zone can be accurately and easily known.

The control device 20 is installed in the central control room, and controls the damper drive device 24 of the air supply device 8 based on the detection signal from the grate temperature measurement device 19 to adjust the opening degree of the damper 23. This is how it is done. This control device 20 uses a computer.

When the temperature of the entire grate 11, 12 is measured from the back side of each stoker 3, 4, 5 by the infrared camera 25, this is image-processed by computer graphics and displayed on the display 26. It is displayed as a high curve and is also color-coded to help you understand the temperature.

Thereby, the temperature of all the grates 11 and 12 and the movement of the main combustion zone above the stoker 4 can be detected accurately and easily.

When the temperature of the grates 11 and 12 and the position of the main combustion zone are detected, the control device 2
0 controls the damper drive device 24, and adjusts the opening degree of each damper 23 so that the amount of air fed to each stoker 3, 4, 5 becomes an optimal value. That is, the amount of air fed to each stoker 3, 4, 5 is
The temperatures of the grates 1 and 12 are adjusted to keep them below the temperature that causes high-temperature corrosion, and are adjusted so that the dust on the grates 11 and 12 is properly dried and burned.

In this way, by adjusting the amount of air fed to each stoker 3, 4, 5, all the grate 11,
The temperature of the fire grate 12 is regulated to maintain the life of the grates 11 and 12, and the drying and combustion rate of the garbage is regulated so that a good combustion condition can be obtained at all times.

FIG. 4 is a schematic vertical cross section of a waste incinerator using an automatic combustion control device according to another embodiment of the present invention, and this automatic combustion control device controls a portion of the exhaust gas in the flue to each stoker 3, The system is equipped with an exhaust gas circulation device 27 that can feed the air below the air supply device 8 and the exhaust gas circulation device 27 based on the detection signal from the grate temperature measuring device 19.
and is configured to control.

That is, the exhaust gas circulation device 27 is composed of an exhaust gas duct 28 connected to the flue and the air duct 21, a circulation fan 29 interposed in the exhaust gas duct 28, etc., and the circulation fan 29 is connected to the control device 2.
0.

When the temperature of the grate 11, 12 and the position of the main combustion zone are detected by the grate temperature measuring device 19, the control device 20 controls the damper drive device 24 and the circulation fan based on this detection signal. control 29,
A part of the exhaust gas is mixed with the air sent from the forced air blower 22 and sent below each stoker 3, 4, 5.

As a result, combustion on the grates 11 and 12 is suppressed, and the temperature of the grates 11 and 12 is reliably lowered and kept below the temperature that causes high-temperature corrosion.
The generation of NOx will also be suppressed.

FIG. 5 is a schematic vertical cross-sectional view of a garbage incinerator using an automatic combustion control device according to still another embodiment of the present invention, and this automatic combustion control device receives a detection signal from a grate temperature measuring device 19. Control device 2 based on
0 controls the air supply device 8 and the exhaust gas circulation device 27, and each stoker drive device 18 is controlled by the control device 2.
0 is controlled so that the stoker speed can also be adjusted.

When the temperature of the grate 11, 12 and the position of the main combustion zone are detected by the grate temperature measuring device 19, the control device 20 controls the damper drive device 24 and the circulation fan based on this detection signal. control 29,
A part of the exhaust gas is sent to each stoker 3, 4, along with air.
5 is sent below. Further, the control device 20 controls the stoker drive device 18 to adjust the stoker speed to an optimum value.

This makes it possible to suppress the burnup in the main combustion zone where combustion is too intense on the grates 11 and 12, prevent high-temperature corrosion of the grates 11 and 12 and the generation of NOx, and improve the combustion condition. The amount of steam generated by the boiler 6 can be controlled stably and accurately.

(Effects of the Invention) As described above, in the automatic combustion control device of claim 1, the temperature change of the entire grate of each stoker is detected by the grate temperature measuring device consisting of an infrared camera, and based on this detection signal. Since the air supply device is controlled by the control device, it is possible to accurately and easily detect the temperature of the grate and the movement of the main combustion zone above the stoker, and the amount of air supplied to each stoker can be adjusted to the optimal value. It can be adjusted as desired. As a result, the temperature of the grate can be adjusted to the optimum temperature, preventing high-temperature corrosion of the grate, and providing good combustion conditions at all times.

Furthermore, in the automatic combustion control device of claim 2,
In addition to the above effects, the following effects can be achieved.

That is, since a part of the exhaust gas is sent below each stoker by the exhaust gas circulation device, combustion on the grate is suppressed and the generation of NOx can be prevented.

Furthermore, the automatic combustion control device according to the third aspect of the present invention can provide the following effects in addition to the above-mentioned effects.

In other words, since the control device controls the stoker drive device and adjusts the stoker speed, the combustion condition is more stable, the amount of steam generated by the boiler can be accurately controlled, and combustion control is completely automated. can be achieved.

[Brief explanation of the drawing]

Fig. 1 is a schematic vertical cross-sectional view of a waste incinerator using the automatic combustion control device according to the present invention, Fig. 2 is a schematic partial perspective view of a stepped stoker of the waste incinerator, and Fig. 3 is a grate of each stoker. 4 is a schematic vertical cross-sectional view of a waste incinerator using an automatic combustion control device according to another embodiment, and FIG. 5 is a contour curve diagram of the entire structure, and FIG. FIG. 6 is a schematic vertical cross-sectional view of a conventional garbage incinerator. 3, 4, 5 are stokers, 8 is an air supply device, 1
1 and 12 are grate, 18 is stoker drive device, 1
9 is a grate temperature measuring device, 20 is a control device, 25
26 is an infrared camera, 26 is an indicator, and 27 is an exhaust gas circulation system.

Claims (1)

[Claims] 1. An air supply device 8 for supplying air below a plurality of sets of stokers 3, 4, 5, and each stoker 3, 4,
A grate temperature measuring device 19 measures the temperature change of the entire grate 11, 12 of No. and a control device 20 that controls the intake device 8 and adjusts the amount of air fed to each stoker 3, 4, 5 so that the temperature of all the grates 11, 12 is below the temperature that causes high temperature corrosion. The grate temperature measuring device 19 is disposed below each stoker 3, 4, 5, and the grate temperature measuring device 19 is disposed below each stoker 3, 4, 5.
2, an infrared camera 25 connected to the control device 20 that detects temperature changes over the entire grate 2, and a display 26 connected to the control device 20 and displaying the temperature distribution of the entire grate 11, 12. Features: Automatic combustion control device for garbage incinerators. 2. The automatic combustion control device for a waste incinerator according to claim 1, further comprising an exhaust gas circulation device 27 that is controlled by the control device 20 and sends a portion of the exhaust gas in the flue below each of the stokers 3, 4, and 5. 3. The automatic combustion control device for a waste incinerator according to claim 2, further comprising a stoker drive device 18 that is controlled by the control device 20 and adjusts the stoker speed of each of the stokers 3, 4, and 5.