JP2918453B2 - Method and apparatus for controlling exhaust gas temperature at startup in refuse 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 refuse incinerator capable of preventing the discharge of polluted exhaust gas by controlling the temperature of the exhaust gas at the time of starting (starting up) the refuse incinerator using a bag filter type dust collector. The present invention relates to a method and an apparatus for controlling exhaust gas temperature at startup.

[0002]

2. Description of the Related Art As shown in FIG. 3, a conventional refuse incinerator has a discharge path 2 for exhaust gas discharged from a furnace body 1.
In order from the furnace body 1 side, an economizer 4 for preheating water supplied to a boiler drum 3 mounted on the furnace body 1, a gas cooling tower 5 for cooling exhaust gas to a predetermined temperature, and removing dust and pollutants from the exhaust gas. A bag filter type dust collector (hereinafter abbreviated as a bag filter) 6 to be repaired and a chimney 7 for gas discharge are arranged. When the exhaust gas temperature is lower than 150 ° C., the bag filter 6 forms dew on the filter. As a measure to prevent this, an exhaust gas bypass pipe 8 is connected to the exhaust path 2 before and after the bag filter 6, and a branch portion thereof is provided. Are provided with open / close dampers 9 and 10 in the discharge path 2 and the exhaust gas bypass pipe 7, respectively.

[0003]

The economizer 4 is supplied with water from a water supply tank 11 through a first water supply pipe 13 having a water supply pump 12 interposed therebetween, and is preheated.
Hot water is supplied to the boiler drum 3 via the second water supply pipe 14. The high-temperature steam heated by the heat of the furnace main body 1 via the boiler water pipe is sent to the power generation turbine 16 via the steam supply pipe 15, and the low-temperature steam discharged from the power generation turbine 16 is supplied to the steam discharge pipe From 17, the water is returned to the water supply tank 11 via the condenser 18. Reference numeral 19 denotes a turbine bypass pipe for passing low-temperature steam.

Normally, when starting up a refuse incinerator, as shown in FIG. 4, natural gas, kerosene and the like are burned to raise the temperature inside the furnace body 1. The exhaust gas at this time is exhausted from the chimney through the exhaust gas bypass pipe 7, but contains almost no dust or pollutants, and there is no problem. However, when the temperature of the exhaust gas at the inlet of the bag filter 6 becomes 150 ° C., refuse is introduced into the furnace main body 1, the heat source is switched to refuse, and the exhaust gas is also closed by closing the exhaust gas bypass pipe 8.
To collect dust.

At this time, the water supply pump 12 is started and the economizer 6 and the boiler drum 3 are removed from the water supply tank 11.
Water is supplied to Then, when water is injected into the economizer 6, the temperature of the exhaust gas decreases a, and the exhaust gas temperature at the inlet of the bag filter 6 may become 150 ° C. or lower. 7 had to be discharged. However, this exhaust gas is incineration exhaust gas of refuse, contains dust and pollutants, and promotes air pollution.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a method and an apparatus for controlling the temperature of flue gas at the time of startup of a refuse incinerator capable of preventing the discharge of polluted exhaust gas at the time of startup of the refuse incinerator. .

[0007]

In order to solve the above-mentioned problems, a method for controlling the temperature of exhaust gas at startup in a refuse incinerator according to the present invention is directed to an economizer interposed in the course of supplying water from a water supply tank to a boiler drum of a furnace body. Can be heated by the exhaust gas discharged from the furnace body, and the exhaust gas discharged through the economizer can be discharged through the bag filter dust collector, or the waste can be discharged by bypassing the bag filter dust collector. in the rising gel incinerators, until a predetermined temperature by detecting the temperature of the water in the water supply tank, a water supply directly into the boiler drum from the water supply tank, bypassing the economizer feed water to the boiler drum And economizer
-The temperature of the water in the boiler drum
Power is detected, and the water temperature detected by the economizer is
When approaching the saturation temperature obtained from the value,
By supplying a predetermined amount of water to the economizer,
This is to prevent the generation of steam in the nomiser .

[0008]

The apparatus for controlling the temperature of flue gas at the time of startup in a refuse incinerator according to the present invention preheats water from a water supply tank to a boiler drum provided in the furnace body in the course of discharging flue gas discharged from the furnace body. In a refuse incinerator provided with an economizer to be supplied, a bag filter type dust collector, and an exhaust gas bypass pipe bypassing the bag filter type dust collector, a first water supply pipe connected from a water supply tank to the economizer is provided. A bypass pipe is provided between the economizer and the second water supply pipe connected to the boiler drum, a bypass pipe is provided for bypassing the economizer, a first control valve is provided in the bypass pipe, and a bypass pipe is provided at the branch economizer side. A second control valve is provided in one water supply pipe, and a first water temperature gauge for detecting a water temperature of the water supply tank is provided. When the waste incinerator is started, the first water temperature meter is detected. A control device for controlling the first control valve and second control valve is provided on the basis of the value, economizer
A second water thermometer that detects the water temperature in the inside, and the pressure of the boiler drum
A pressure gauge is installed to detect
A second water temperature gauge and a pressure gauge
It is configured to control the opening of the control valve .

[0010]

[0011]

According to the above construction, when starting up a refuse incinerator, natural gas, kerosene, etc. are burned to raise the temperature inside the furnace body,
When the temperature of the exhaust gas exceeds the dew point of the bag filter type dust collector, refuse is injected into the furnace body and burned, and the temperature of the exhaust gas further increases. At this time, the control device causes the water in the water supply tank to bypass the economizer based on the water temperature of the water supply drum until the water in the economizer does not adversely affect the bag filter even if the exhaust gas is cooled. Since the water is supplied to the boiler drum, it is possible to prevent the temperature of the exhaust gas from lowering due to the economizer at startup, and thus to discharge the exhaust gas after collecting it with a bag filter. It is possible to prevent the emission of polluted exhaust gas during startup.

Further, by detecting the water temperature in the economizer and the pressure in the boiler drum, the saturation temperature in the economizer is calculated. Based on this, the water supply to the economizer is reduced to such an extent that the temperature of exhaust gas does not decrease. Thus, evaporation can be reliably prevented, and damage to an economizer or the like due to overheating can be prevented.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a refuse incinerator according to the present invention will be described below with reference to FIGS. The same members as those in the related art are denoted by the same reference numerals, and description thereof will be omitted.

As shown in FIG. 1, the water in the water supply tank 11 is supplied to the boiler drum 3 through the economizer 4 to the first water supply pipe 13 and the second water supply pipe 14 near the entrance and exit of the economizer 4. An economizer bypass pipe (bypass pipe) 21 is connected. The first control valve (the first control valve) is connected to the economizer bypass pipe 21.
Control valve) 22 and a second control valve (second control valve) 23 interposed downstream of the first water supply pipe 13 at the branching point (on the economizer 6 side). By means of 20, the first and second control valves 22 and 23 are operated.

The water supply tank 11 is provided with a first water temperature gauge 24 for detecting the water temperature, and a second water temperature detector for detecting the water temperature in the economizer 4 at the outlet of the economizer 4.
A water temperature gauge 25 is provided, and each detection signal is output to the controller 20. Furthermore, boiler drum 3
Is provided with a drum pressure gauge 26 for detecting the boiler pressure, and the detected value is also output to the controller 20.

As shown in the control block diagram of FIG. 2, the controller 20 controls opening and closing of the first and second control valves 22 and 23 based on the water temperature of the water supply tank 11 detected by the first water temperature gauge 24. Based on the first control system and the pressure of the boiler drum 3 detected by the drum pressure gauge 26 and the water temperature at the outlet of the economizer 4 detected by the second water temperature gauge 25, the second control valve 23
And a second control system for controlling the opening degree of the motor.

That is, the first control system includes the water tank 1
Since the temperature of the water supplied from 1 to the economizer 4 is low, the temperature of the exhaust gas is lowered, and the water from the water supply tank 11 is supplied to the economizer bypass pipe 21 when the incinerator is started up, which adversely affects the bag filter 6. Supplies water directly to the boiler drum 3 by bypassing the economizer 4, and the water tank 11 detected by the first water temperature gauge 23.
Is compared with the set value B of the setter 31 by the comparator 32. When A ≧ B, the first control valve 22 is fully closed by turning on the relay RY1,
The operation of fully opening the second control valve 23 is performed.

The second control system is provided to prevent the economizer 4 from being overheated more than necessary and exceeding the saturation temperature to generate steam and adversely affect the boiler. Based on the detected drum pressure, the saturation temperature f of water under that pressure in the converter 33
(x) is calculated, and the set value set in the setter 35, for example, 5-10 ° C. is subtracted from the saturation temperature by the subtractor 34, and the supply set value C, and the economizer detected by the second water temperature meter 24. The water temperature D at the outlet of No. 4 is compared with the comparator 36, and when C ≧ D, the relay RY2 is turned on. Further, the water temperature D at the outlet of the economizer 4 detected by the second water temperature gauge 25 is set by the subtracter 37 to the set value KC of the setter 38.
Is input to the computing unit 39 only when it exceeds the threshold value, and an operation signal for operating the opening degree of the second control valve 23 according to the water temperature D is output from the computing unit 39.

According to the above configuration, when starting up the incinerator, the starting burner burns natural gas or kerosene to heat the furnace body 1 and raise the temperature of the furnace body 1 to a temperature at which the exhaust gas can pass through the bag filter 6, for example, 140. When the temperature reaches ° C, dust is introduced into the furnace main body 1 to start combustion, and the open / close damper 9 is closed to close the exhaust gas bypass pipe 8, and the exhaust gas is introduced into the bag filter 6. Then, the water supply pump 12 is started to supply water from the water supply tank 11 to the boiler drum 3. However, since the water temperature of the water supply tank 11 is low, the first control valve 22 is fully opened by the controller 20 and the second control valve is opened. The valve 23 is fully closed, and is supplied by the economizer bypass pipe 21 bypassing the economizer 4. When the water temperature of the water supply tank 11 reaches a predetermined value at which there is no problem even if it affects the exhaust gas, for example, 140 ° C., the first control valve 22 is fully closed by the controller 20 and the second control valve 23 is fully opened. Is supplied to the economizer 4. Therefore, since the exhaust gas is not excessively cooled by the water flowing through the economizer 4 and the temperature does not decrease, the exhaust gas does not need to bypass the bag filter 6 and can be started up in a short time.

Further, when there is a possibility that the economizer 4 is excessively heated during startup and steam is generated, the boiler pressure detected by the drum pressure gauge 26 and the boiler pressure detected by the second water temperature gauge 24 are detected. Based on the water temperature at the outlet of the economizer 4, the controller 20 opens the second control valve 23 by a predetermined amount to supply low-temperature water from the water supply tank 11, thereby cooling the water in the economizer 4 and evaporating it. By controlling the opening degree of the second control valve 23, the temperature of the exhaust gas can be prevented from lowering.

Therefore, the temperature of the exhaust gas can be prevented from lowering from the time when the incineration of the refuse is started, and the exhaust gas can be discharged after being subjected to the dust collection processing by the bag filter 6, and the untreated polluted exhaust gas is discharged into the atmosphere. Nothing to do.

[0022]

As described above, according to the present invention, when starting up a refuse incinerator, natural gas, kerosene, etc. are burned to raise the temperature inside the furnace body, and the exhaust gas is collected in a bag filter type dust collector. When the temperature exceeds the dew point, waste is charged into the furnace body and burned, and the temperature of the exhaust gas is further increased. At this time, the control device causes the water in the water supply tank to bypass the economizer based on the water temperature of the water supply drum until the water in the economizer does not adversely affect the bag filter even if the exhaust gas is cooled. Since the water is supplied to the boiler drum, it is possible to prevent the temperature of the exhaust gas from lowering due to the economizer at startup, and thus to discharge the exhaust gas after collecting it with a bag filter. It is possible to prevent the emission of polluted exhaust gas during startup.

Further, the saturation temperature in the economizer is calculated by detecting the water temperature in the economizer and the pressure in the boiler drum, and the water supply to the economizer is reduced to such an extent that the temperature of the exhaust gas does not decrease. Thus, evaporation can be reliably prevented, and damage to an economizer or the like due to overheating can be prevented.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing one embodiment of a refuse incinerator according to the present invention.

FIG. 2 is a control block diagram showing a controller of the refuse incinerator.

FIG. 3 is a configuration diagram showing a conventional refuse incinerator.

FIG. 4 is a graph showing changes in exhaust gas temperatures at the inlet and outlet of an economizer when a conventional incinerator is started.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Furnace main body 2 Exhaust gas discharge path 3 Boiler drum 4 Economizer 6 Bag filter type dust collector 8 Exhaust gas bypass pipe 9 Opening / closing damper 10 Opening / closing damper 11 Water tank 13 First water supply pipe 14 Second water supply pipe 20 Controller 21 Economizer pipe Pipe 22 First control valve 23 Second control valve 24 First water temperature gauge 25 Second water temperature gauge 26 Drum pressure gauge

Claims (2)

(57) [Claims] An economizer interposed in the middle of supplying water from a water supply tank to a boiler drum of a furnace body is heated by exhaust gas discharged from the furnace body, and the exhaust gas discharged through the economizer is collected in a bag filter type. during or discharged through the vessel, or during bypass the bag filter type dust collector riser gel drainable waste incinerator, to a predetermined temperature by detecting the temperature of the water in the water supply tank the boiler with the feedwater to the boiler drum to bypass the economizer and water directly into the boiler drum from the water supply tank, for detecting the temperature of the water in the economizer
Detects the pressure in the drum and obtains the water temperature detection value of the economizer from the pressure detection value.
When the temperature approaches the saturation temperature, the water in the water tank is
By supplying to the conomizer,
A method for controlling exhaust gas temperature at start-up in a refuse incinerator characterized by preventing generation of steam . 2. An economizer for preheating water from a water supply tank and supplying the preheated water to a boiler drum provided in the furnace main body, and a bag filter type dust collector in a discharge path of exhaust gas discharged from the furnace main body. In a refuse incinerator provided with an exhaust gas bypass pipe that bypasses the bag filter type dust collector, a first water supply pipe connected from the water supply tank to the economizer and a second water supply pipe connected from the economizer to the boiler drum
A bypass pipe that bypasses the economizer is provided between the water supply pipes, a first control valve is provided on the bypass pipe, and a second control valve is provided on the first water supply pipe on the branch economizer side of the bypass pipe; A first water thermometer for detecting a water temperature of a water supply tank is provided, and a control device for controlling the first control valve and the second control valve based on a detection value of the first water thermometer when a waste incinerator is started up is provided. , A second water thermometer that detects the water temperature in the economizer,
A pressure gauge is installed to detect the pressure of the rubber drum.
It controls the opening of the second control valve based on the value detected by the force meter.
An exhaust gas temperature control device at the time of startup in a refuse incinerator, wherein the temperature control device is configured as follows .