JPH05248618A - Co controlling method in incinerator - Google Patents

Abstract

PURPOSE:To keep a combustion gas temperature in a post-combustion region at a reference temperature and reduce the concentration of co. CONSTITUTION:Combustion gas temperature at a post-combustion region 4 of a secondary combustion chamber 1B of an incinerator 1 is measured. In the case that the combustion gas temperature at the post-combustion region 4 is lower than a reference temperature, the secondary air blown from the post-combustion region 4 at the secondary combustion chamber 1B is increased or decreased and the secondary air is controlled in such a manner that the combustion gas temperature becomes the reference temperature. In the case that the temperature within the incinerator is lower than the reference temperature even if the secondary air in the post-combustion region 4 is controlled, a concentration of CO2 in the combustion gas at the post-combustion region 4 is measured and in turn when the concentration of CO is excessively high, an amount of the air blown from the air duct is restricted.

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 a municipal solid waste incinerator or a waste incinerator for reducing carbon monoxide in the incinerator by measuring the temperature and O ₂ concentration in the incinerator.

[0002]

2. Description of the Related Art In recent years, in order to suppress the generation of dioxins generated from municipal waste incinerators and waste incinerators, it has become an important subject to reduce the CO concentration in the incinerators. Then, in order to reduce the CO concentration for that purpose, it is necessary to operate the incinerator while controlling the following elements.

[0003] Maintain a high combustion gas temperature of 800 ° C or higher. ． Ensure a sufficiently long residence time of the combustion gas in the high temperature range. ． Increase the O ₂ concentration in the incinerator.

As a conventional method of reducing the CO concentration to satisfy the above requirements, the CO concentration in the exhaust gas in the incinerator is measured, and the amount of secondary air blown into the secondary combustion chamber is adjusted based on the measured value. Then, the unburned gas was completely burned.

[0005]

However, the combustion gas temperature and the O ₂ concentration in the incinerator differ depending on the location in the incinerator.
Moreover, it is easy to maintain the combustion gas temperature above the reference temperature of 800 ° C. on the dry zone side of the secondary combustion chamber, but it is easy to maintain the reference temperature on the post-combustion zone side due to large variations in the combustion gas temperature. is not. Further, the O ₂ concentration in the combustion gas is low on the dry zone side and high on the post-combustion zone side.

Therefore, on the dry zone side of the secondary combustion chamber, it is possible to relatively easily obtain a high combustion gas temperature of 800 ° C. or higher and reduce the CO concentration by blowing a large amount of secondary air. On the combustion zone side, if the secondary air is blown too much, the O ₂ concentration will increase, but the combustion gas temperature on the post combustion zone side will drop, and there is a problem that it is not useful for reducing the CO concentration.

The present invention solves the above problems, and an object of the present invention is to provide a CO control method in an incinerator which can reduce the CO concentration by maintaining the combustion gas temperature on the post combustion zone side at a reference temperature. And

[0008]

In order to solve the above-mentioned problems, the CO control method in the incinerator of the present invention measures the combustion gas temperature in the after-combustion zone side of the secondary combustion chamber of the incinerator, and the after-combustion is performed. When the combustion gas temperature on the belt side is below the reference temperature,
Even if the secondary air blown from the post combustion zone side of the secondary combustion chamber is increased or decreased to control the secondary air so that the combustion gas temperature becomes the reference temperature, and the secondary air on the post combustion zone side is controlled, When the temperature is below the reference temperature, the O ₂ concentration in the combustion gas on the post combustion zone side is measured, and when the O ₂ concentration is excessive, the amount of air blown from the air duct is reduced.

[0009]

With the above structure, the temperature of the post combustion zone side of the secondary combustion chamber of the incinerator is measured, and when the temperature of the post combustion zone side is equal to or higher than the reference temperature, the secondary air is blown, and when the temperature is equal to or lower than the reference temperature. The secondary air is controlled so that the temperature of the post combustion zone side becomes the reference temperature by increasing or decreasing the secondary air. Even if the secondary air is controlled and the temperature in the furnace is below the reference temperature, the concentration of O ₂ is changed. When the measured O ₂ concentration is excessive, the CO concentration is reduced by squeezing the air from the air duct so as not to lower the temperature of the combustion gas in the secondary combustion chamber.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. In FIG. 1, a drying zone 2, a combustion zone 3 and a post-combustion zone 4 are formed by a stoker inside the incinerator 1, and a hopper 5 and a pusher are provided on one side of the incinerator 1 on the drying zone 2 side. 6 is provided. Further, below the drying zone 2, the combustion zone 3 and the after-combustion zone 4, air ducts 7 for supplying combustion air are opened, and communicate with a blower 9 via a damper device 8.

A secondary combustion chamber 1B is formed in the incinerator 1 above the main combustion chamber 1A, and the secondary combustion chamber 1B is formed on the wall surface of the incineration furnace 1 on the dry zone 2 side and the wall of the post combustion zone 4 side. Respectively, the secondary air blowing port 10 is open, and each secondary air blowing port 10 is connected to the blower 9 via the damper device 8.
A temperature sensor 11 is provided on the side of the post combustion zone 4 of the incinerator 1.
And the O ₂ sensor 12 are arranged, and each damper device 8
The temperature sensor 11 and the O ₂ sensor 12 are control devices 13
It is connected to the.

The operation of the above structure will be described below.
The dust thrown into the hopper 5 is cut out onto the dry zone 2 by the pusher 6 and is moved from the dry zone 2 to the combustion zone 3 and from the combustion zone 3 to the post-combustion zone 4 by driving the stoker. In the dry zone 2, the dust is burned by receiving the air supplied from the air duct 7, and in the combustion zone 3 and the post-combustion zone 4, the dust is burned by receiving the air supplied from the air duct 7. The dry zone 2 is rich in combustible dust, but has a low O ₂ concentration, so that the combustion gas temperature rises and the CO concentration can be lowered by adding a relatively large amount of secondary air.

On the other hand, on the side of the post-combustion zone 4, there is little dust to be burned, and simply blowing in a large amount of secondary air will not lower the temperature of the combustion gas and will not lead to a reduction in CO concentration.
Therefore, the combustion gas temperature on the side of the post-combustion zone should be kept above the reference temperature (usually this temperature is around 800 ° C) to reduce the CO concentration, and the temperature should be controlled to be always above 800 ° C. To do. Therefore, the temperature sensor 1
The temperature of the combustion gas on the post combustion zone side is measured by 1 and the opening degree of each damper device 8 is adjusted by the control device 13 based on the measured value to blow the secondary air from the secondary air blowing port 10 on the post combustion zone side. The distribution of the next air amount and the air amount supplied from the air duct 7 is adjusted.

That is, the temperature of the temperature sensor 11 is 800
If it is above ℃, it is considered that the combustion dust is still combusting in the post combustion zone 4, so even if secondary air is blown in,
O concentration can be reduced. However, if the temperature of the temperature sensor 11 is 800 ° C. or lower, the amount of secondary air is adjusted so that the temperature of the temperature sensor 11 is 800 ° C. or higher. That is, if the temperature of the temperature sensor 11 rises when the amount of secondary air is increased, it means that the amount of O ₂ on the side of the post-combustion zone 4 is insufficient, so the blowing of secondary air is continued. When the temperature of the temperature sensor 11 is also by increasing the quantity of secondary air to the reverse of 800 ° C. or less, O ₂ by O ₂ sensor 12
The concentration is measured. If the amount of O ₂ is excessive, the amount of combustion dust is small.
Is controlled to reduce the amount of air supplied from the air duct 7. Particularly, it is effective to throttle the air in the post combustion zone 4 and the dry zone 2.

A temperature sensor 11 and an O ₂ sensor 12
The installation position of is not limited to the place shown in FIG.
The reference temperature is measured and an appropriate position associated with the reduction of CO concentration is selected and provided.

[0016]

As described above, according to the present invention, the temperature of the post-combustion zone side of the secondary combustion chamber of the incinerator is measured, and when the temperature of the post-combustion zone side is below the reference temperature, the secondary air is discharged. Is controlled to control the secondary air so that the temperature on the post combustion zone side becomes the reference temperature. Even if the secondary air is controlled, the O ₂ concentration is measured when the temperature in the furnace is equal to or lower than the reference temperature, When the O ₂ concentration is excessive, the air from the air duct is throttled to maintain the temperature of the combustion gas in the secondary combustion chamber so as not to be lowered, so that the CO concentration in the combustion gas can be reduced.

[Brief description of drawings]

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

[Explanation of symbols]

1 Incinerator 4 Afterburning Zone 7 Air Duct 8 Damper Device 9 Blower 10 Secondary Air Inlet 11 Temperature Sensor 12 O ₂ Sensor

Claims (1)

[Claims] 1. The combustion gas temperature in the post-combustion zone side of the secondary combustion chamber of the incinerator is measured. When the combustion gas temperature in the post-combustion zone side is lower than the reference temperature, the post-combustion zone side of the secondary combustion chamber is measured. If the temperature in the furnace is below the reference temperature even if the secondary air is controlled so that the combustion gas temperature becomes the reference temperature by controlling the secondary air blown from A method for controlling CO in an incinerator, which comprises measuring the O ₂ concentration in the combustion gas on the side of the post combustion zone and, when the O ₂ concentration is excessive, reducing the amount of air blown from an air duct.