JPH0510514A - Incineration method of refuse and apparatus therefor - Google Patents

Abstract

PURPOSE:To prevent hazardous components from being discharged during incineration of refuse. CONSTITUTION:Refuse is pyrolytically decomposed in a pyrolysis section 1 and combustible gas is led to a constricted flow path 3 to mix it with secondary air and then to a gas combustion section 2. The combustible gas mixed with secondary air is completely burned in the gas combustion section 2 to decompose hazardous dioxin and its precursors.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a waste incineration method and apparatus.

[0002]

2. Description of the Related Art In a conventional waste incinerator, a single combustion chamber burns waste with primary air,
The unburned gas was burned by supplying secondary air to burn the waste.

[0003]

In the conventional combustion furnace incineration method, since the waste is burned in one combustion chamber, mixing the combustible gas with the air is satisfactory only by introducing air into the combustion chamber. In addition, the combustible gas is discharged without effectively utilizing the space inside the combustion chamber, and the sufficient residence time required for combustion cannot be taken. Since there is a difference and a uniform high combustion temperature atmosphere is not created, harmful dioxin and its precursor are discharged as they are without complete combustion.

The present invention overcomes these drawbacks of the prior art,
An object of the present invention is to provide a waste incineration method and an apparatus for the same, in which combustible gas is completely burned to decompose dioxin and its precursors and organic toxic substances are not emitted.

[0005]

SUMMARY OF THE INVENTION According to the present invention, waste is pyrolyzed in a pyrolysis unit, and a combustible gas in the pyrolysis unit is introduced into a squeezing passage to be mixed with secondary air and then introduced into a gas combustion unit. And a combustible gas mixed with the secondary air is combusted in the gas combusting section, and a thermal decomposition section having a waste input port, and a thermal decomposition section provided above the thermal decomposition section. Waste incineration, comprising: a gas combustion unit; a squeezing passage connecting the upper portion of the thermal decomposition unit to the gas combustion unit; and a secondary air supply pipe provided in the squeezing passage. It relates to the device.

[0006]

[Operation] The combustible gas generated in the thermal decomposition section is mixed with the secondary air supplied from an appropriate point in the squeezing passage while monitoring the temperature of the gas at the outlet of the squeezing passage, and a sufficient residence time is maintained in the gas combustion section. It burns at high temperatures and decomposes harmful dioxin and its harmful organic compounds.

[0007]

Embodiments of the present invention will now be described with reference to the drawings.

FIG. 1 is a longitudinal sectional view of an embodiment of the device of the present invention,
2 is a cross-sectional view taken along line II-II of FIG. 1. As shown in FIG. 1, a gas combustion unit 2 is provided above the thermal decomposition unit 1, and a small diameter is provided above the thermal decomposition unit 1. The lower end of the pipe-shaped squeezing passage 3 is open, the squeezing passage 3 extends toward the lower portion of the gas combustion unit 2, and the upper end of the squeezing passage 3 is, as shown in FIG. It is connected to the lower portion of the gas combustion unit 2 from the tangential direction.

As shown in FIG. 1, the thermal decomposition section 1 is provided with a waste input port 4 and a burner 5, and the waste input port 4
The waste that has been put into the inside of the thermal decomposition section 1 is thermally decomposed into gas, oil, char (charcoal) by the fluidized medium 6 such as sand that has been preheated by the burner 5. Char (charcoal) generated by thermal decomposition is burned by the air for flow from the air diffuser 7,
Supplies the heat required for the thermal decomposition of waste.

Reference numeral 8 denotes a secondary air supply pipe, which branches into one or a plurality of flow paths from the middle and is connected to different portions of the squeezing passage 3 through control valves 9. In the illustrated embodiment, three secondary air supply pipes are provided. Reference numeral 10 is a thermometer that opens and closes the control valve 9 and determines the position of the secondary air supplied to the squeezing passage 3 based on the detected temperature. When the combustible gas component is constant, one secondary air supply pipe may be used.

A burner 11 for igniting a combustible gas mixed with secondary air is attached to the gas combustion section 2 for starting operation when the temperature of the gas combustion section 2 is low or for misfire. The combustion section 2 is provided with a dust outlet 12 and a combustion gas outlet 13.

Next, the operation will be described.

Ignition of the burner 5 shown in FIG.
The waste is introduced from the waste inlet 4 into the fluidized bed in which the fluid medium 6 is flowing by the air for flowing from the air diffuser 7 inside.

Since the fluidized medium 6 is preheated by the burner 5, the waste introduced into the thermal decomposition section 1 through the waste introduction port 4 is heated and decomposed into gas, oil, char (charcoal), The char burns in the fluidized bed by the air for flowing from the air diffuser 7, and the heat generated by the burning accelerates the thermal decomposition of the waste. At this time, since the thermal decomposition section 1 and the gas combustion section 2 are separated and independent of each other, the thermal decomposition section 1 uses the gas combustion section 2
The thermal decomposition rate of the waste can be kept constant without being affected by the temperature.

The combustible gas generated by the thermal decomposition of the waste in the thermal decomposition section 1 rises in the thermal decomposition section 1 and is guided to the squeezing passage 3, and flows from the secondary air supply pipe 8 through the control valve 9. Mix with secondary air. Since the squeezing passage 3 is a narrow passage, the combustible gas guided from the thermal decomposition section 1 to the squeezing passage 3 is completely mixed with the secondary air. At this time, since the thermal decomposition rate of the thermal decomposition section 1 is constant, the supply amount of the secondary air is also stable, so that it is possible to prevent the problem of lowering of combustion temperature or incomplete combustion due to excess or deficiency of secondary air.

The supply position of the secondary air mixed with the combustible gas in the squeezing passage 3 is adjusted by opening and closing the control valve 9 according to the temperature detected by the thermometer 10, and the combustible gas is burned in the narrow squeezing passage 3. The control is performed so that the fly ash particles entrained in the combustible gas do not melt and block the narrow squeezing passage 3. That is, when the temperature detected by the thermometer 10 is low, the upstream side (lower part)
The control valve 9 is opened so that secondary air is introduced from the upstream side to perform sufficient mixing, and when the temperature detected by the thermometer 10 is high, the control valve 9 on the downstream side (upper side) is opened. Combustion in the squeezing passage 3 is suppressed.

The combustible gas mixed with the secondary air in the squeezing passage 3 is introduced tangentially from the lower side surface of the gas combustion section 2, becomes a swirling flow in the gas combustion section 2, and is ignited by the ignition burner 11 to 800 ° C. Complete combustion at the above temperature.

The combustible gas is swirled in a high temperature atmosphere of 800 ° C. or more in the gas combustion section 2 to be agitated and completely combusted, so that harmful substances contained in the combustible gas and fly ash particles entrained in the combustible gas are contained. Dioxins and their precursors are decomposed in the gas combustion section 2. As a result, the exhaust gas discharged from the combustion gas discharge port 13 contains almost no harmful dioxins and their precursors. The coarse particles of fly ash particles entrained in the combustible gas are discharged from the dust discharge port 12.

When the scale of the incinerator is large, a plurality of squeezing passages 3 are provided so that the combustible gas and the secondary air are completely mixed.

3 to 5 are vertical sectional views of other embodiments of the apparatus of the present invention, in which the same parts as those in FIG. 1 are designated by the same reference numerals.

In the embodiment of FIG. 3, the upper end of the squeezing passage 3 is tangentially connected to the upper side surface of the gas combustion section 2, and the combustion gas discharge port 13 is tangentially provided on the lower side surface of the gas combustion section 2. Has been.

In the embodiment shown in FIG. 3, the combustible gas mixed with the secondary air in the squeezing passage 3 is introduced tangentially from the upper side surface of the gas combustion section 2 and agitated in a swirling flow in a high temperature atmosphere. As it descends, it completely burns, and dioxin and its precursor are decomposed in the gas combustion section 2. The exhaust gas containing almost no dioxin and its precursor is discharged from the combustion gas discharge port 13 on the lower side surface of the gas combustion unit 2, and the coarse particles are discharged from the dust discharge port 12 on the lower side.

In the embodiment shown in FIG. 4, the upper end of the squeezing passage 3 is connected to the top of the gas combustion section 2, and the combustion gas discharge port 13 is provided beside the dust discharge port 12 provided at the lower end of the gas combustion section 2.
Is provided.

In the embodiment shown in FIG. 4, the combustible gas mixed with the secondary air draws a streamline in opposition to the gas density due to combustion, so that stirring of the mixed gas is promoted and combustion becomes active.

In the embodiment of FIG. 5, the upper end of the squeezing passage 3 is tangentially connected from the side surface of the intermediate portion of the gas combustion section 2,
It is designed to generate a swirling flow that goes up and down.

FIG. 6 shows another embodiment of the one shown in FIG. 1, in which a stoker furnace type thermal decomposition section 14 is applied in place of the fluidized bed type thermal decomposition section 1, and another example is shown. The structures of the squeezing passage 3, the secondary air supply pipe 8 and the gas combustion unit 2 are the same as those in FIG.

The stoker furnace-type thermal decomposition section 14 includes a waste input port 4, a stoker 15, and a supply device 16 for quantitatively supplying the waste input from the waste input port 4 onto the stoker 15. A burner 5 and a combustion air supply pipe 17 for supplying combustion air to the lower side of the stoker 15. The combustible gas generated by the thermal decomposition of waste on the stoker 15 is squeezed passage 3 It is adapted to be guided to the gas combustion section 2 via.

In the embodiment of FIG. 6, the thermal decomposition section 14 is of a stoker furnace type, and thermal decomposition is performed on the stoker 15,
Combustible gas generated by thermal decomposition is the same as in Fig. 1,
It is guided to the gas combustion unit 2 and completely burned, and harmful dioxin and its precursor are sufficiently decomposed.

Further, it is of course possible to apply the stoker furnace type pyrolysis section 14 shown in the embodiment of FIG. 6 in combination with the gas combustion section 2 as shown in FIGS.

[0030]

According to the present invention, the thermal decomposition section and the gas combustion section are separated and independent, so that the thermal decomposition rate of the waste is kept constant without being affected by the temperature of the gas combustion section. It is possible to suppress fluctuations in the amount of combustible gas generated, thus stabilizing the supply amount of secondary air and not decomposing the dioxin and its precursor due to a decrease in gas combustion temperature when the secondary air is excessive, In addition, dioxin and its precursors are not left in a residual state due to incomplete combustion when secondary air is insufficient, and an appropriate amount of secondary air can be mixed with combustible gas to sufficiently decompose dioxin and its precursors. .

Further, since the secondary air is introduced into the combustible gas through the narrow squeezing passage, the combustible gas and the secondary air can be mixed uniformly.

Further, in the gas combustion section, the agitation of the mixed gas becomes vigorous, the combustible gas is completely combusted, and harmful dioxin and its precursor can be decomposed sufficiently.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of an embodiment of the device of the present invention.

FIG. 2 is a sectional view taken along line II-II of FIG.

FIG. 3 is a vertical sectional view of another embodiment of the device of the present invention.

FIG. 4 is a vertical sectional view of still another embodiment of the device of the present invention.

FIG. 5 is a vertical sectional view of still another embodiment of the device of the present invention.

FIG. 6 is a vertical sectional view showing still another embodiment of the device of the present invention.

[Explanation of symbols] 1 Pyrolysis part 2 gas combustion section 3 spillway 4 Waste input port 5 burners 8 Secondary air supply pipe 11 Ignition burner 14 Thermal decomposition part

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Minoru Asai             3-15 Toyosu, Koto-ku, Tokyo Ishikawajima             Harima Heavy Industries Ltd. Technical Research Center (72) Inventor Yasunori Ando             Stone, Shin-Nakahara-cho, Isogo-ku, Yokohama-shi, Kanagawa             Kawashima Harima Heavy Industries Ltd. Technical Research Center

Claims (2)

[Claims] 1. The waste is pyrolyzed in a pyrolysis unit,
The combustible gas in the thermal decomposition section is introduced into the squeezing passage and mixed with secondary air, and then introduced into the gas combustion section, and the combustible gas mixed with the secondary air is combusted in the gas combustion section. Waste incineration method. 2. A thermal decomposition part having a waste input port, a gas combustion part provided above the thermal decomposition part, a squeezing passage connecting the upper part of the thermal decomposition part to the gas combustion part, and A waste incinerator, comprising: a secondary air supply pipe provided in a squeezing passage.