JPH04340014A - Method of regulating blast volume to incinerator - Google Patents

Abstract

PURPOSE:To provide mixing and stirring of the combustion gas and secondary air surely by supplying secondary air which mixes steam in the secondary combustion chamber of an incinerator and increasing or decreasing the secondary air volume based on the combustion gas volume that is measured in the secondary combustion chamber and, at the same time, compensating for the volume of decrease with a steam volume. CONSTITUTION:A secondary damper device 10 is provided on the suction side of a secondary air blower 11, and steam is supplied to the discharge side from an exhaust heat boiler through a flow rate control valve 14 and it is blown out from an air blow- out port provided in the secondary combustion chamber 4 and, at the same time, the combustion gas volume is measured by a flow rate meter 15. Based on the values measured by this flow rate meter 15 a controller controls the combustion air blower, etc. as well as the secondary damper device 10, secondary air blower 11, and flow rate control valve 14 in order to bring the secondary air volume to a proper value, and a decrease of gas in the secondary air is supplemented by an increase in the steam volume. Accordingly the discharge pressure and flow rate of the mixture gas are secured over a certain value and the combustion gas and secondary air are well stirred, and the concentration of CO is reduced and it is possible to prevent a drop in the ambient temperature and suppress the formation of dioxines.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for adjusting the amount of air 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.
CO control is carried out by adjusting the combustion state of the incinerator through feedback control, such as measuring the CO concentration of the combustion exhaust gas with a CO meter and adjusting the main combustion air amount and secondary air amount based on the measured value. I was going.

[0006]

However, in the conventional configuration described above, when the amount of secondary air to be supplied is small, the discharge pressure of the secondary air jetted toward the combustion gas in the secondary combustion chamber and There was a problem in that the flow velocity became low and the mixing of combustion gas and secondary air deteriorated, resulting in an increase in CO concentration and the production of dioxins despite the supply of an appropriate amount of air.

[0007] The present invention solves the above problems, and even a small amount of secondary air can be ejected into the combustion gas with sufficient discharge pressure and flow velocity to reliably mix and stir the combustion gas and the secondary air. The purpose is to provide a method for adjusting the amount of air in an incinerator.

[0008]

[Means for Solving the Problems] In order to solve the above problems, the method for adjusting the amount of air in an incinerator according to the present invention supplies secondary air mixed with steam to the secondary combustion chamber of the incinerator, and Measures the amount of combustion gas in the secondary combustion chamber, adjusts the amount of secondary air ejected into the combustion gas based on the measured value, and compensates for the decrease in the amount of gas in the secondary air by increasing the amount of steam. It is configured to do this.

[0009]

[Operation] With the above-described structure, the combustion gas is mixed with secondary air in the secondary combustion chamber of the incinerator to undergo secondary combustion. At this time, the amount of air required for secondary combustion changes with the increase or decrease in the amount of combustion gas, so the amount of secondary air is adjusted according to the amount of combustion gas, and the decrease in the amount of secondary air is replaced by steam. Complement by an increase in quantity. By doing this, the total amount of the mixture of secondary air and steam ejected into the combustion gas is maintained at the required amount, and the discharge pressure and flow rate of the mixture are maintained above a certain value regardless of the increase or decrease in the amount of secondary air. .

[0010] Therefore, by injecting secondary air adjusted according to the amount of combustion gas into the combustion gas with sufficient discharge pressure and flow rate necessary for mixing and stirring with the combustion gas, the combustion gas and secondary air can be mixed. By making the mixing state appropriate, the CO concentration is reduced, and by using steam as a gas to compensate for the decrease in the amount of gas in the secondary air, the decrease in atmospheric temperature in the secondary combustion chamber is suppressed, and the precursors of dioxins are reduced. Controls the generation of dioxins by suppressing the generation of substances.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. In FIGS. 1 and 2, an incinerator 1 has a main combustion chamber 3 composed of a plurality of combustion zones 2, and a secondary combustion chamber 4 formed above the main combustion chamber 3. Further, a blower duct 5 is opened below each combustion stag 2, and a combustion air blower 6 and a main damper device 7 are interposed at the base end side of the blower duct 5. Furthermore, damper devices 7a, 7b, 7c, 7d, and 7e are interposed in the middle of each ventilation duct 5.

[0012] The secondary combustion chamber 4 of the incinerator 1 is provided with an air outlet 8, and the air outlet 8 is communicated with a secondary air duct 9. Further, a secondary damper device 10 and a secondary blower 11 are interposed in the middle of the secondary blower duct 9, and the steam supply pipe 1 is connected to the discharge side of the secondary blower 11.
2 are provided. This steam supply pipe 12 communicates with a waste heat boiler 13 provided adjacent to the incinerator 1, and a flow rate control valve 14 is interposed in the middle of the steam supply pipe 12.

Furthermore, a flow meter 15 is provided in the secondary combustion chamber 4, and the flow meter 15 is connected to the control device 1 via a signal line.
Connected to 6. Furthermore, the control device 16 includes a combustion blower 6, a main damper device 7, damper devices 7a, 7b, 7c,
7d, 7e, secondary air blower 11 and secondary damper device 10
and the flow rate control valve 14 are connected.

The operation of the above configuration will be explained below. Combustion air is supplied to the main combustion chamber 3 from a combustion air blower 6 through a blower duct 5, and the garbage on each combustion zone 2 is incinerated by receiving the combustion air. Further, the combustion gas flows upward from the main combustion chamber 3 into the secondary combustion chamber 4, passes through the secondary air blower 11, the secondary air duct 9, and mixes with the secondary air jetted out from the air outlet 8. secondary combustion. At this time, the secondary air is supplied as a mixed gas with steam supplied from the steam supply pipe 12.

[0015] Then, the secondary combustion chamber 4 is detected by the flow meter 15.
Based on the measured value, the control device 16 controls the combustion blower 6, the main damper device 7, the damper devices 7a, 7b, 7c, 7d, 7e, and the secondary air blower 11.
The secondary damper device 10 and the flow rate control valve 14 are appropriately controlled to adjust the amount of combustion air supplied to the main combustion chamber 3 and the amount of secondary air ejected into the combustion gas to appropriate values, and to control the amount of secondary air. The decrease in the amount of gas is compensated for by the increase in the amount of steam.

In other words, since the amount of air required for secondary combustion changes as the amount of combustion gas increases or decreases, the amount of secondary air is adjusted depending on the amount of combustion gas, and the decrease in the amount of gas in the secondary air is This is supplemented by an increase in the amount of steam to maintain the total amount of the secondary air/steam mixture ejected into the combustion gas at the required amount. As a result, secondary air adjusted according to the amount of combustion gas is ejected into the combustion gas with sufficient discharge pressure and flow velocity necessary for mixing and stirring with the combustion gas, and the mixing state of the combustion gas and secondary air is maintained. Reduce CO concentration as appropriate. In addition, by using steam as a gas to compensate for the decrease in the amount of gas in the secondary air, a decrease in the atmospheric temperature in the secondary combustion chamber 4 is suppressed, and the generation of dioxins precursor substances is suppressed, thereby suppressing the formation of dioxins. do.

[0017]

[Effects of the Invention] As described above, according to the present invention, the amount of secondary air is adjusted according to the amount of combustion gas, and the decrease in the amount of gas in the secondary air is compensated for by increasing the amount of steam. , the discharge pressure and flow rate of the mixed gas can be maintained above a certain value regardless of the increase or decrease in the amount of secondary air.
The CO concentration is reduced by sufficient stirring and mixing of combustion gas and secondary air, and the use of steam suppresses the drop in atmospheric temperature in the secondary combustion chamber, suppressing the generation of dioxins precursor substances and reducing dioxins. The generation of can be suppressed.

[Brief explanation of drawings]

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

FIG. 2 is an enlarged vertical cross-sectional view of the secondary combustion chamber in the same embodiment.

[Explanation of symbols]

Claims (1)

[Claims] Claim 1: Supplying secondary air mixed with steam to the secondary combustion chamber of the incinerator, measuring the amount of combustion gas in the secondary combustion chamber of the incinerator, and ejecting it into the combustion gas based on the measured value. 1. A method for adjusting the amount of air in an incinerator, the method comprising adjusting the amount of secondary air to be used, and compensating for a decrease in the amount of gas in the secondary air by increasing the amount of steam.