JP2758090B2 - CO control method in 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 method for controlling CO in an incinerator for suppressing the generation of dioxins in a municipal waste incinerator or a waste incinerator.

[0002]

2. Description of the Related Art In recent years, environmental pollution by dioxins generated from municipal waste incinerators and waste incinerators has become a problem. The following factors are important for controlling dioxins in incinerators.

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

[0004] For this reason, it has been considered to reduce carbon monoxide (CO), which is a representative index of unburned gas and has a strong correlation with dioxins. Conventionally, secondary air has been supplied to the secondary combustion chamber to complete combustion of the unburned gas contained in the exhaust gas, thereby reducing the CO concentration.

[0005]

In the above-mentioned conventional structure, when the oxygen amount in the secondary combustion chamber becomes excessive, the ambient temperature decreases, and instead, the CO increases. Therefore, there is a problem that it becomes impossible to maintain a high combustion gas temperature, and it is necessary to supply an appropriate amount of oxygen according to the combustion state in the secondary combustion chamber.

However, since the adjustment of the amount of oxygen supplied to the secondary combustion chamber involves the adjustment of the amount of secondary air, if the amount of oxygen is reduced, the required flow rate cannot be obtained due to the decrease in the amount of gas. There is a problem that the fuel gas or CO cannot be sufficiently mixed with the supplied oxygen. On the other hand, if the required flow rate is to be obtained in consideration of stirring and mixing, there is a problem that the amount of oxygen becomes excessive due to an increase in the amount of gas. Was.

The present invention has been made to solve the above-mentioned problem, and aims to sufficiently mix secondary air and exhaust gas while keeping the amount of oxygen supplied by secondary air to the minimum necessary to maintain a high combustion gas temperature while maintaining a high combustion gas temperature. It is another object of the present invention to provide a method for controlling CO in an incinerator capable of suppressing the generation of dioxins.

[0008]

Means for Solving the Problems In order to solve the above problems, a method for controlling CO in an incinerator according to the present invention is to supply an appropriate amount of secondary air to a secondary combustion chamber of the incinerator and to supply the secondary air from the incinerator. Part of the discharged flue gas is separately and separately supplied to the secondary combustion chamber as an agitated airflow, and the secondary air secures the minimum amount of oxygen necessary for the combustion of unburned gas in the secondary combustion chamber. At the same time, the secondary air and the unburned gas are sufficiently stirred by the stirring airflow.

[0009]

According to the above configuration, by using the exhaust gas discharged from the incinerator as the agitated air flow, the wind speed and the air volume required for stirring the unburned gas and the secondary air without affecting the oxygen amount in the secondary combustion chamber. In the combustion control of the incinerator, the action of stirring the unburned gas and the secondary air can be controlled as an independent element separately from the control of the oxygen amount. Conversely, in the combustion control of the incinerator, the control of the amount of oxygen can be controlled as an independent element separate from the agitation of the unburned gas and the secondary air, so the amount of oxygen supplied by the secondary air is minimized. It is possible to secure sufficient stirring of the unburned gas and the secondary air while keeping the temperature to a minimum, maintain a high combustion gas temperature, and suppress the production of CO and dioxins.

[0010]

An embodiment of the present invention will be described below with reference to the drawings. In FIG. 1, a stoker 2 is provided inside an incinerator 1.
A dry zone, a combustion zone, and a post-burn zone are formed by the
An air duct 3 for supplying combustion air is provided below each stoker 2. A secondary combustion chamber 4b is formed above the main combustion chamber 4a of the incinerator 1. The flue of the incinerator 1 communicates with an exhaust gas treatment system 6 including a dust collector 5 and the like.

The secondary combustion chamber 4b is provided with a secondary air blowing port 7 for blowing secondary air and a stirring flow blowing port 8 for blowing a stirring fluid. The agitated flow inlet 8 communicates with the air supply device 10 via the first damper device 9, and the exhaust gas treatment system 6 of the incinerator 1 via the second damper device 11 and the circulation blower 12.

The operation of the above configuration will be described below.
In the main combustion chamber 4a of the incinerator 1, the refuse is
Combustion air supplied from the stoker 2 is burned on each stoker 2, and exhaust gas containing unburned gas such as CO flows into the secondary combustion chamber 4b from the main combustion chamber 4a.

Secondary air supplied by an air supply device 10 is blown into a secondary combustion chamber 4b from a secondary air inlet 7 through a first damper device 9 and a dust collection device of an exhaust gas treatment system 6. The exhaust gas passing through 5 is blown from the stirring flow blowing port 8 via the second damper device 11 by the circulation blower 12.

Therefore, the main combustion chamber 4a is moved from the secondary combustion chamber 4
The exhaust gas flowing into b is subjected to a stirring action by the stirring airflow spouting from the stirring flow blowing port 8 and re-combustes while being sufficiently stirred with the secondary air supplied from the secondary air blowing port 7.

Therefore, by adjusting the first damper device 4a and supplying an appropriate amount of secondary air from the secondary air inlet 7 to the secondary combustion chamber 4b of the incinerator 1, it is necessary to burn unburned gas. While ensuring the minimum amount of oxygen, the second damper device 11 is adjusted to blow a part of the exhaust gas discharged from the incinerator 1 from the agitated flow inlet 8 into the secondary combustion chamber 4b with an appropriate wind speed and amount. Thereby, in the combustion control of the incinerator 1, the stirring action of the unburned gas and the secondary air can be controlled as an independent element separated from the control of the oxygen amount,
Conversely, in the combustion control of the incinerator 1, the control of the oxygen amount can be controlled as an independent element separately from the stirring operation of the unburned gas and the secondary air. Therefore, sufficient stirring of the unburned gas and the secondary air is ensured while keeping the supply amount of oxygen by the secondary air to the minimum necessary, and a high combustion gas temperature is maintained.
Generation of O and dioxins can be suppressed.

[0016]

As described above, according to the present invention, by using the exhaust gas discharged from the incinerator as the stirring gas flow,
In the combustion control of the incinerator, the control of the amount of oxygen can be separated from the control of the amount of oxygen by separating the agitating action of the unburned gas and the secondary air and controlling the amount of oxygen. While ensuring sufficient stirring of the unburned gas and the secondary air, it is possible to maintain the high combustion gas temperature and suppress the generation of CO and dioxins.

[Brief description of the drawings]

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

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Incinerator 4b Secondary combustion chamber 6 Exhaust gas treatment system 7 Secondary air inlet 8 Stirred flow inlet

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ identification code FI F23L 9/04 F23L 9/04 (58) Fields investigated (Int.Cl. ⁶ , DB name) F23G 5/00 F23G 5/14 F23G 5/44 F23G 5/50 F23L 9/04

Claims (1)

(57) [Claims] 1. An appropriate amount of secondary air is supplied to a secondary combustion chamber of an incinerator, and a part of the combustion exhaust gas discharged from the incinerator is separately and separately supplied to the secondary combustion chamber as a stirring gas stream. supply and ensure the minimum amount of oxygen necessary for the combustion of the unburned gas in the secondary combustion chamber with the secondary air, and sufficiently agitate the secondary air and the unburned gas with the stirring airflow. A method for controlling CO in an incinerator.