JPH06221532A - Incinerator - Google Patents

Abstract

PURPOSE:To reduce discharging of dioxine and the like by a method wherein secondary air is supplied into a smoke passage communicating between a primary combustion chamber and a secondary combustion chamber. CONSTITUTION:An air nozzle 20 is arranged in a smoke passage 14 communicating between a primary combustion chamber 10 and a secondary combustion chamber 13, secondary air is injected from the air nozzle 20 into the smoke passage 14. Since the smoke passage 14 has a relative small sectional area, it is possible to perform an approximate uniform supplying of air over an entire sectional area. Then, when combustion discharged gas of ignited item passes within the smoke passage 14, a superior contact with air can be performed an the discharged gas and the air are flowed into the secondary chamber 13 while they are well mixed to each other. As a result, unburned gas is rapidly decomposed as soon as it flows into the secondary combustion chamber 13, and a staying time in the secondary combustion chamber 13 can be effectively utilized. With such an arrangement as above, it is possible to reduce a discharging of organic chloride compound of hard decomposing characteristic such as dioxine and the like.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an incinerator for municipal solid waste and industrial wastes, and in particular, improves combustion in a secondary combustion chamber to improve combustibility and to develop a persistent organic chlorine compound such as dioxins. It relates to an incinerator that decomposes.

[0002]

2. Description of the Related Art The generation of dioxins and the like in an incinerator for municipal waste and industrial waste is caused by CO in the incinerator combustion exhaust gas.
There is a positive correlation with the concentration, and it is presumed that the concentration of dioxins increases as the CO concentration of the incinerator combustion exhaust gas increases. In the guidelines for prevention of dioxin generation, which was announced by the Environment Improvement Division, Ministry of Health and Welfare, Ministry of Health and Welfare in December 1990, the CO concentration of incinerator combustion exhaust gas was used as an index of dioxin generation.

On the other hand, conventionally, a vertical two-stage incinerator has been used as an incinerator for municipal waste and industrial waste, particularly as a small incinerator. For example, various smokeless refuse incinerators described in Japanese Patent Publication No. 45-12638. The following types have been proposed. The structure of a conventional vertical two-stage incinerator will be described in detail with reference to FIGS. FIG. 4 is a front view of a conventional vertical two-stage incinerator, and FIG. 5 is a sectional view taken along line BB of FIG.

In FIGS. 4 and 5, a primary combustion chamber 1 having a cylindrical shape is provided with a door 3 for incineration and a lid 2 which can be opened and closed at one end, and an upper combustion for supplying combustion air at the other end. An air vent 8 is provided. Further, a lower combustion air port 9 for supplying combustion air is provided in the hearth of the primary combustion chamber 1. A secondary combustion chamber 4 is installed above the primary combustion chamber 1 to gasify and burn the incinerator combustion exhaust gas so as to eliminate smoke. The primary combustion chamber 1 is connected via a flue 5 to the secondary combustion chamber 1. Is in communication with. The secondary combustion chamber 4 is provided with a burner 6 for supplying high-temperature gas or flame and a chimney 7 for discharging combustion exhaust gas of incineration material.

In the conventional vertical two-stage incinerator configured as described above, when the incineration object input door 3 is opened to inject the incineration object on the hearth of the primary combustion chamber 1, the incineration object is generated. It is heated by the flame of a burner (not shown), and progresses through drying, burning, and post-burning over time. Then, when the incineration object burns, an incineration object combustion exhaust gas is generated, and the incineration object combustion exhaust gas reaches the secondary combustion chamber 4 through the flue 5, where the burner 6 burns the incineration object. The unburned portion of the combustion exhaust gas is burned and discharged from the chimney 7 to the outside of the system in a smokeless state.

[0006]

However, it was feared that these conventional vertical two-stage incinerators would not be able to obtain a sufficient effect in reducing the persistent chlorine compounds such as dioxins. That is, in the above-mentioned conventional vertical two-stage incinerator, in the secondary combustion chamber 4, a part of the unburned gas containing CO, hydrocarbons, etc. is discharged without being decomposed,
Further, dioxins and the like generated in the incinerator are not decomposed and are discharged in a relatively large amount. Also, even if it undergoes thermal decomposition, it is not completely decomposed to carbon dioxide, it stops in a partially oxidized state, and unburned organic carbon content exists in the unburned gas, so temperature conditions in the exhaust gas treatment process in the latter stage, etc. As a result, dioxin is regenerated again.

The combustion exhaust gas from the incineration material is composed of unburned gas containing CO, hydrocarbons and the like, and combustion gas containing a relatively large amount of oxygen. In order to completely decompose carbon dioxide in an unburned gas containing CO, hydrocarbons and the like in the secondary combustion chamber, the secondary combustion chamber must be (1) in a high temperature atmosphere (800-1
000 ° C.), (2) a sufficient retention time for decomposition, and (3) a good mixed state of unburned gas and air are essential conditions. Particularly in the case of a high temperature gas, the viscosity of the gas becomes significantly higher than that at room temperature, so the mixing of unburned gas with air in (3) is important.

On the other hand, in the conventional method, since the combustion gas of the dust and the upper combustion air are supplied to the secondary combustion chamber without being sufficiently mixed, it takes time to mix them in the secondary combustion chamber. However, as a result, there is a problem that sufficient decomposition of unburned gas cannot be obtained. Therefore, the present invention provides an incinerator that enhances the contact and mixing of gas and air at the time when the gas flows into the secondary combustion chamber, and reduces the emission of persistent organic chlorine compounds such as dioxins to the utmost limit. The purpose is to do.

[0009]

SUMMARY OF THE INVENTION The present invention has a flue or a flue which has an incinerator door and a primary combustion chamber to which combustion air is supplied from combustion air supply means and which communicates with the atmosphere. In an incinerator in which an exhaust port connected to a chimney is arranged and a secondary combustion chamber having a cylindrical shape is connected via a flue, an air nozzle is provided in the flue that connects the primary combustion chamber and the secondary combustion chamber. Is provided, and secondary air is ejected. Since the flue has a relatively small cross-sectional area, air can be supplied almost evenly over the entire cross-section. Therefore, when the incineration combustion exhaust gas passes through the flue and makes good contact with the air, the exhaust gas and the air flow into the secondary combustion chamber in a mixed state. As a result, the unburned gas is decomposed more quickly than when it flows into the secondary combustion chamber, and the residence time in the secondary combustion chamber can be effectively utilized, so that a large reduction effect can be obtained.

[0010]

Embodiments of the present invention will be described below with reference to FIGS. 1 is a transverse sectional view of the incinerator of the present invention, and FIG. 2 is a sectional view taken along the line AA of FIG.

In FIGS. 1 and 2, a door 12 and a lid 11 for injecting an object to be incinerated are openably and closably attached to one end of a primary combustion chamber 10, and a lower combustion chamber for supplying combustion air is attached to a hearth of the primary combustion chamber 10. An air port 19 is provided. A secondary combustion chamber 13 is installed above the primary combustion chamber 10 for gasifying and burning the incineration material combustion exhaust gas to eliminate smoke. The primary combustion chamber 10 is connected via a flue 14. Communicate with. Further, an air nozzle 20 is arranged in the communication flue 14 so that the air 21 is spread over the entire cross section of the flue.

In the embodiment shown in FIGS. 1 and 2, an example is shown in which the incineration object loading door 12 is opened and closed by manual operation to throw in dust, but a function of automatically opening and closing via a cylinder or the like is added. , May be automated. Further, the automated incinerator loading door may be arranged at the other end of the primary combustion chamber 10, and an incinerator loading device may be installed in front of the incinerator loading door.

Although FIG. 2 shows an example in which the nozzles 20 are installed at three positions, it is preferable that the nozzles 20 are arranged so that air can be supplied to the entire cross section at one or more positions. The jet direction of air may be horizontal, or as shown in FIG.
0 may be arranged with an inclination so as to face the gas 22 and be ejected.

Next, with reference to FIGS. 1 to 3, the combustion state of the incinerator and the flow of the incinerator combustion exhaust gas in the incinerator of the present invention configured as described above will be described. The material to be incinerated in the primary combustion chamber 10 is heated by the flame of a burner (not shown) arranged in the primary combustion chamber 10, and progresses over time such as drying, burning, and post-combustion. At that time, the combustion air is supplied to the incineration object through the combustion air supply means. When the incineration object burns, incineration object combustion exhaust gas is generated. The incineration object combustion exhaust gas 22 comes into contact with the air 21 ejected from the air nozzle 20 provided in the flue 14 and is mixed with the secondary air 21 Since it flows into the combustion chamber 13, the decomposition of unburned gas in the secondary combustion chamber 13 progresses rapidly.

Next, the combustion effect of the present invention will be described with reference to Table 1. The table shows the CO concentration of the incinerator combustion exhaust gas in the present invention. For comparison, the results of the conventional method are also shown in the table. In the present invention, the CO concentration of the combustion exhaust gas from incineration is 30 to 70 ppm, and the conventional method is 80.
˜200 ppm, and comparing the present invention and the conventional method, it can be seen that the CO concentration in the incinerator combustion exhaust gas in the present invention is extremely small. Further, in the present invention, the target value of 100 ppm or less of the mechanized batch furnace determined by the guidelines for prevention of generation of dioxins has been achieved.

[0016]

[Table 1]

[0017]

EFFECTS OF THE INVENTION By supplying secondary air into the flue that connects the primary combustion chamber and the secondary combustion chamber, the incinerator combustion exhaust gas and the air are brought into contact with each other. As a result, the combustion exhaust gas of the incineration material and the air are mixed at the time of flowing into the secondary combustion chamber, so that the unburned gas is rapidly decomposed in the secondary combustion chamber. As is clear from the above description, the present invention can significantly reduce the CO concentration in the combustion exhaust gas of incineration materials as compared with the conventional vertical two-stage incinerator.
We can provide an incinerator that can comply with guidelines for prevention of dioxins generation announced in February.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of an incinerator of the present invention.

FIG. 2 is a sectional view taken along line AA of FIG.

[Fig. 3] Example of arrangement of air nozzles

FIG. 4 is a front view of a conventional vertical two-stage incinerator.

5 is a sectional view taken along line BB of FIG.

[Explanation of symbols]

10 Primary combustion chamber, 13 Secondary combustion chamber, 14 Flue, 2
0 air nozzle

Claims (1)

[Claims] 1. A flue that has an incineration object loading door and connects the primary combustion chamber to which combustion air is supplied from the combustion air supply means to the atmosphere, or an exhaust port that is connected to a chimney. In an incinerator in which a secondary combustion chamber having a cylindrical shape is connected via a flue, an incinerator characterized in that secondary air is supplied into the flue that connects the primary combustion chamber and the secondary combustion chamber. Furnace.