JPH04324015A - Co control method in incinerator - Google Patents

Abstract

PURPOSE:To increase the secondary air volume in order to maintain the combustion gas at a high temperature by a method wherein the secondary air is supplied to an incinerator after adjusted by a damper and heated by a heater. CONSTITUTION:An incinerator includes a combustion chamber 3 having two or more combustion zones 2, a secondary combustion chamber 4 located above the combustion chamber 3 and air ducts 5 that open under the combustion zones 2. Two or more air blow nozzles 8 are provided on the secondary combustion chamber 4 and communicate with a secondary air ducts 10 via dampers 9. A heater 11 and a secondary air fan 12 are equipped on the secondary air duct 10. Secondary air 18 heated by the heater 11 is supplied by the secondary air fan 12 to the combustion waste gas rising from the combustion chamber 3 to the secondary combustion chamber 4 and the waste gas is secondarily burned. The secondary air is maintained at an adequate feed rate by controlling the valve lift of the secondary dampers 9 corresponding to outputs from a CO meter 14.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a CO control method in an incinerator for suppressing the generation of dioxins in a municipal waste incinerator or a waste incinerator.

0002

BACKGROUND OF THE INVENTION In recent years, environmental pollution due to dioxins generated from municipal waste incinerators and waste incinerators has become a problem. In order to suppress dioxins in an incinerator, the following factors are important.

[0003]■. Maintain high combustion gas temperature. ■． Ensure a sufficiently long residence time of combustion gas in the high temperature range. ■． Good mixing of unburned gas and air in combustion gas.

[0004] However, direct analysis of dioxins requires expensive analytical equipment and advanced techniques, and is not suitable for continuous analysis. To this end, it has been considered to monitor carbon monoxide (CO), which is a representative indicator of unburned gas and has a strong correlation with dioxins.

[0005] Conventionally, CO was stored in the middle of the flue of an incinerator.
The CO concentration of the combustion exhaust gas is measured using a CO meter, and the combustion state of the incinerator is adjusted by feedback control such as adjusting the amount of combustion air based on the measured value.
It was under O control.

[0006] Also, secondary air is supplied to the secondary combustion chamber to burn unburned gas in the exhaust gas and to reduce CO in the secondary combustion chamber.
Efforts were being made to reduce the concentration.

[0007]

[Problems to be Solved by the Invention] In the conventional configuration described above, when the amount of oxygen in the secondary combustion chamber becomes excessive, the atmospheric temperature decreases, and on the contrary, CO increases, and the decrease in reaction heat further causes the atmospheric temperature in the furnace to decrease. There is a problem that the temperature of the combustion gas decreases and it becomes impossible to maintain a high combustion gas temperature, so it is necessary to supply an appropriate amount of oxygen depending on the combustion state in the secondary combustion chamber.

However, adjusting the amount of oxygen supplied to the secondary combustion chamber involves adjusting the amount of secondary air, so if you try to reduce the amount of oxygen, you will not be able to obtain the required flow rate due to the decrease in the amount of gas, and the There is a problem that the fuel gas or CO and the supplied oxygen cannot be mixed sufficiently, and on the other hand, when trying to obtain the required flow rate by considering stirring and mixing, there is a problem that the amount of oxygen becomes excessive due to the increase in the amount of gas. Ta.

[0009] The present invention solves the above-mentioned problems, and it is possible to supply secondary air with a small amount of gas to the secondary combustion chamber at a sufficient flow rate, maintain a high combustion gas temperature, and reduce CO2.
Another object of the present invention is to provide a CO control method in an incinerator that can suppress the production of dioxins.

0010

[Means for Solving the Problems] In order to solve the above problems, the CO control method of the present invention adjusts the secondary air supplied to the secondary combustion chamber of the incinerator according to the amount of air required in the secondary combustion chamber. The secondary air is controlled by a damper device, heated by a heating device, and then supplied to the secondary combustion chamber of the incinerator.

Further, the CO control method of the present invention adjusts the amount of secondary air supplied from a plurality of air blowing nozzles to the secondary combustion chamber of the incinerator using a damper device according to the amount of air required in the secondary combustion chamber. , the number of air blowing nozzles that blow out secondary air is adjusted by a damper device according to the amount of secondary air.

0012

[Operation] With the above configuration, the amount of oxygen in the secondary combustion chamber is maintained at an appropriate value by adjusting the amount of secondary air. At this time, when the amount of secondary air decreases, the flow velocity of the secondary air blown into the secondary combustion chamber tends to decrease due to the decrease in the amount of gas, but the secondary air is heated by the heating device to increase its volume. By increasing this, the decrease in the flow velocity of secondary air is suppressed.

Therefore, even when the amount of secondary air decreases, the secondary air can be supplied to the secondary combustion chamber at the required flow rate, and the secondary air supplied to the secondary combustion chamber and the unburned air in the secondary combustion chamber can be It is possible to supply an appropriate amount of air according to the combustion state in the secondary combustion chamber while ensuring sufficient stirring and mixing of the gas and CO. Furthermore, by supplying an appropriate amount of oxygen, the generation of CO is suppressed, the amount of reaction heat increases, and the atmospheric temperature inside the furnace rises, which maintains a high combustion gas temperature, thereby suppressing the production of dioxins. .

[0014] Furthermore, with the second configuration described above, the amount of oxygen in the secondary combustion chamber is maintained at an appropriate value by controlling the amount of secondary air. At this time, when the amount of secondary air decreases, the flow velocity of the secondary air blown into the secondary combustion chamber tends to decrease due to the decrease in the amount of gas. By increasing the amount of secondary air blown out from each air blowing nozzle, a decrease in the flow velocity of the secondary air is suppressed.

Therefore, even when the total amount of secondary air decreases, the secondary air can be supplied from the air blowing nozzle to the secondary combustion chamber at the required flow rate, and the secondary air supplied to the secondary combustion chamber and the secondary An appropriate amount of air can be supplied in accordance with the combustion state in the secondary combustion chamber while ensuring sufficient stirring and mixing with unburned gas and CO in the combustion chamber. Furthermore, by supplying an appropriate amount of oxygen, the generation of CO is suppressed, the amount of reaction heat increases, and the atmospheric temperature inside the furnace rises, which maintains a high combustion gas temperature, thereby suppressing the production of dioxins. .

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. 1 to 2, an incinerator 1 has a combustion chamber 3 composed of a plurality of combustion zones 2, and a secondary combustion chamber 4 formed above the combustion chamber 3. In addition, each combustion stagnation 2
A ventilation duct 5 is opened below the ventilation duct 5.
A combustion air blower 6 and a damper device 7 are interposed on the proximal end side.

A plurality of air blowing nozzles 8 are provided in the secondary combustion chamber 4, and each air blowing nozzle 8 is connected to a secondary air blowing duct 10 via a secondary damper device 9.
is connected to. A heating device 11 and a secondary air blower 12 are interposed in the middle of this secondary air blowing duct 10. Further, the flue 13 of the incinerator 1 is provided with a CO meter 14 as a CO detection means, and the CO detection means is not limited to the CO meter 14, but may be of a type using image processing or the like. Further, the CO meter 14 is connected to the control device 15,
A secondary damper device 9 is connected to the control device 15.

The operation of the above configuration will be explained below. Combustion air 16 is supplied to the combustion chamber 3 from a combustion air blower 6 through the ventilation duct 5, and the garbage on the combustion zone 2 is incinerated by receiving the combustion air 16.

Further, the combustion exhaust gas 17 rises from the combustion chamber 3 to the secondary combustion chamber 4, passes from the secondary blower 12 to the secondary air blowing duct 10 and the heating device 11, and from each air blowing nozzle 8 to the secondary combustion chamber. Secondary combustion is performed by receiving secondary air 18 supplied to 4.

[0020] Then, the CO meter 14 detects the combustion exhaust gas 1
7, and inputs the value into the control device 15 to calculate the excess or deficiency of the secondary air amount for the current CO concentration, and operates each secondary damper device 9 to control the secondary combustion chamber. 4. Maintain the secondary air amount at an appropriate value.

At this time, when the amount of secondary air decreases, the flow velocity of the secondary air 18 blown into the secondary combustion chamber 4 tends to decrease due to the decrease in the amount of gas. By heating the air and increasing its volume, the decrease in the flow velocity of the secondary air is suppressed.

Alternatively, by closing an appropriate number of secondary damper devices 9, the number of air blowing nozzles 8 that blow out secondary air 18 can be reduced, and the amount of secondary air blown out from each air blowing nozzle 8 can be increased. This suppresses a decrease in the flow velocity of the secondary air 18.

Therefore, even when the amount of secondary air 18 decreases, the secondary air 18 can be supplied to the secondary combustion chamber 4 at the required flow rate, and the secondary air 18 supplied to the secondary combustion chamber 4 can be
An appropriate amount of air can be supplied according to the combustion state in the secondary combustion chamber 4 while ensuring sufficient stirring and mixing of the unburned gas and CO in the secondary combustion chamber 4. Furthermore, by supplying an appropriate amount of oxygen, the generation of CO is suppressed, the amount of reaction heat increases, and the atmospheric temperature inside the furnace rises, which maintains a high combustion gas temperature, thereby suppressing the production of dioxins. .

[0024]

As described above, according to the present invention, by heating the secondary air with a heating device to increase its volume, it is possible to suppress a decrease in the flow velocity of the secondary air.
Alternatively, by reducing the number of air blowing nozzles that blow out secondary air and increasing the amount of secondary air blowing out from each air blowing nozzle, it is possible to suppress the decrease in the flow velocity of the secondary air, and the secondary air and unburned gas It is possible to supply an appropriate amount of air while ensuring sufficient agitation and mixing with CO and the atmosphere inside the furnace, thereby suppressing the production of dioxins by maintaining a high combustion gas temperature. can.

[Brief explanation of drawings]

FIG. 1 is an overall configuration diagram of an incinerator in one embodiment of the present invention.

FIG. 2 is a plan cross-sectional view of a secondary combustion chamber in the same embodiment.

[Explanation of symbols]

1 Incinerator 3 Combustion chamber 4 Secondary combustion chamber 8 Air blowing nozzle 9 Secondary damper device 11 Heating device

Claims (2)

[Claims] Claim 1: The secondary air supplied to the secondary combustion chamber of the incinerator is controlled by a damper device according to the amount of air required in the secondary combustion chamber, and after this secondary air is heated in a heating device, the incinerator is heated. A method for controlling CO in an incinerator, characterized by supplying CO to a secondary combustion chamber. [Claim 2] An air blower that adjusts the secondary air supplied to the secondary combustion chamber of the incinerator from a plurality of air blowing nozzles according to the amount of air required in the secondary combustion chamber using a damper device, and blows out the secondary air. A method for controlling CO in an incinerator, characterized in that the number of nozzles is adjusted by a damper device according to the amount of secondary air.