JP2953864B2 - Incinerator and method for reducing emission of harmful substances therefrom - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to municipal waste, sewage sludge,
The present invention relates to an incinerator for incinerating and treating garbage such as industrial waste and a method for reducing unburned dioxin discharged from the incinerator.

[0002]

2. Description of the Related Art As an incinerator for incinerating and treating so-called garbage such as municipal garbage, sewage sludge and industrial waste, there is conventionally known an incinerator as exemplified in FIG. As shown in this figure, in the incinerator 1 ′, a combustion chamber 2 ′ is installed at the center thereof, and refuse supply means 3 for supplying refuse to the combustion chamber 2 ′ is provided on one side of the combustion chamber 2 ′. Is provided with a main burner 4. At the top of the incinerator 1 ', there is an exhaust gas outlet 2
1 'is provided.

[0003] The dust supply means 3 comprises a feeder 31 having an impeller 32 provided therein, and a dust supply passage 33 for guiding dust sent from the feeder 31 into the incinerator 1 '. In addition to the main burner 4, an auxiliary burner 4a having a small capacity is provided at a position facing the main burner 4 in the incinerator 1 '.

The bottom of the incinerator 1 'is formed in a mortar shape. At the bottom, a number of fine air tubes 51 communicating with a lower manifold 52 are provided in a vertical direction. An intake 53 is provided. The air fine tube 51, the manifold 52, and the air intake 53 form a combustion air supply unit 5.

[0005] An incombustible discharge pipe 61 for discharging combustion residues is provided from the center of the bottom of the combustion chamber 2 'having a mortar shape, and the lower portion thereof has an incombustible discharge provided with a spiral feeder therein. Machine 62. And
The incombustible discharge mechanism 6 is formed by the incombustible discharge pipe 61 and the incombustible discharger 62.

[0006] In such an incinerator 1 ', refuse D is fed from a feeder 3 together with sand S as a combustion auxiliary material through an inlet.
1 and the dust supply passage 33 as the impeller 32 rotates.
And supplied into the incinerator 1 '. Then, the sand S charged from the specific gravity difference accumulates at the bottom of the incinerator 1 ', and the dust D is placed thereon. Then, combustion air is supplied into the incinerator 1 ′ from an unillustrated blower through the air intake port 53, the manifold 52 and the air capillary 51, the main burner 4 is ignited, and the dust D on the sand S is burned.
The combustion exhaust gas is discharged to the outside from an exhaust gas outlet 21 'provided at the top of the incinerator 1' through a flue (not shown).

[0007] The main burner 4 is used only at the beginning of combustion, and the main burner 4 is stopped and the capacity is reduced from the time when the temperature of the incinerator 1 'becomes high and the refuse D itself starts self-combustion. A small auxiliary burner 4a is ignited, and combustion in the incinerator 1 'is continued only by the auxiliary burner 4a.

Incombustible substances such as ash and metal after combustion and sand S
Is taken out from the bottom of the incinerator 1 'through the incombustible discharge pipe 61 by driving the incombustible discharger 62,
The sand S is separated and reused.

[0009]

Incidentally, in the conventional incinerator 1 'as described above, the flammable gas generated by the thermal decomposition of the refuse D introduced into the combustion chamber 2' is generated by the combustion chamber 2 '. The combustion air and the gas in the combustion chamber 2 ′ are not uniformly diffused into the inside of the combustion chamber 2 ′ and rise as a thin columnar shape toward the exhaust gas outlet 21 ′ provided at the top of the combustion chamber 2 ′. Is not sufficiently mixed, and combustion occurs only in the vicinity of the upward flow of this gas. In particular, the corners of the inner peripheral surface of the furnace wall become dead spaces and become in a state where they hardly participate in the combustion.

For this reason, the gas at the center of the column-shaped ascending flow causes incomplete combustion in the combustion chamber 2 ', and is incinerated in a state where harmful substances such as carbon monoxide and dioxin do not burn and decompose. The inconvenience of being discharged from the furnace 1 'has occurred.

Therefore, conventionally, in order to completely combust the combustible gas generated from the refuse D in the combustion chamber 2 ', FIG.
As shown in the figure, a secondary air introduction hole 22 '
It is also performed to introduce secondary air into the combustion chamber 2 'from there, but even if secondary air is introduced, it vigorously flows from the bottom of the combustion chamber 2' toward the exhaust gas outlet 21 '. It is impossible to uniformly mix the gas and air rising in a columnar shape, and it is difficult to sufficiently suppress the occurrence of the incomplete combustion and the accompanying generation of carbon monoxide and dioxin. That was the current situation.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned conventional problems, and promotes complete combustion by properly mixing air and flammable gas in a combustion chamber. It is an object of the present invention to provide an incinerator for preventing harmful substances such as carbon dioxide and dioxin from being discharged outside the furnace, and a method for reducing harmful substances from the incinerator.

[0013]

According to a first aspect of the present invention, there is provided an incinerator having a combustion chamber having a combustion air supply means at a bottom thereof and a refuse supply means and a burner.
The combustion chamber is divided into an upper combustion chamber and a lower combustion chamber,
The upper combustion chamber and the lower combustion chamber are provided at their center with a communicating portion through which they communicate with each other. The lower combustion chamber is provided with combustion air supply means, dust supply means, and a burner. A plurality of exhaust gas outlets for combustion exhaust gas are provided at the bottom of the peripheral wall of the combustion chamber.

The incinerator according to a second aspect of the present invention is the incinerator according to the first aspect, wherein a secondary air supply hole is provided in the communication portion.

According to a third aspect of the present invention, there is provided a method for reducing the emission of harmful substances from an incinerator, wherein the upper combustion chamber and the lower combustion chamber are divided into two and communicate with each other by a communicating portion having a narrow sectional area. A method of incinerating garbage using a combustion chamber, wherein garbage is supplied to the lower combustion chamber, and primary combustion is performed in the lower combustion chamber by supplying combustion air from the bottom of the lower combustion chamber. After squirting into the upper combustion chamber from the communication part and colliding with the ceiling of the upper combustion chamber, it is lowered along the peripheral wall of the upper combustion chamber to perform complete combustion therebetween, and provided at the bottom of the peripheral wall of the upper combustion chamber. The exhaust gas is discharged from the plurality of exhaust gas outlets.

[0016]

According to the incinerator according to the first aspect, the upper combustion chamber and the lower combustion chamber are provided with a communicating portion in which they communicate with each other at the center thereof, and the lower combustion chamber is supplied with combustion air. Means, refuse supply means, and a burner are provided, and a plurality of discharge ports for combustion exhaust gas are provided at the bottom of the peripheral wall of the upper combustion chamber. Accordingly, the refuse introduced into the lower combustion chamber is heated by the high-temperature sand, self-combustes, and thermally decomposes to generate combustible gas. This combustible gas obtains combustion air supplied from the lower combustion chamber, burns it, becomes a combustion gas, injects it into the upper combustion chamber through the communication part, collides with the ceiling part, and is radially dispersed, The fuel is burned while hanging down the inner peripheral wall and spreading throughout the upper combustion chamber, and is discharged out of the furnace from a discharge port provided at the bottom of the peripheral wall of the upper combustion chamber.

As described above, the air-fuel mixture of combustible gas and combustion air is ejected to the upper combustion chamber from the communicating portion having a reduced cross-sectional area connecting the lower combustion chamber and the upper combustion chamber while burning. Combustion in the upper combustion chamber as it burns without forming a dead space in the room, and when the gas collides with the ceiling, the flow changes direction abruptly and microscopic mixing of gas and air is promoted. The oxidizing gas completely burns, and the harmful substance carbon monoxide becomes carbon dioxide gas, and dioxin is thermally decomposed to eliminate its harmfulness.

According to the incinerator according to the second aspect of the present invention, since the secondary air supply hole is provided in the communication portion, the mixing of the combustible gas and the combustion air further proceeds, and the mixing is further ensured. Their discharge to the outside of the furnace is suppressed.

According to the method for reducing the emission of harmful substances from the incinerator according to the third aspect of the present invention, while the refuse is supplied to the lower combustion chamber and the combustion air is supplied from the bottom thereof, the primary combustion is performed in the lower combustion chamber. After the combustion gas is ejected from the communication portion into the upper combustion chamber to collide with the ceiling of the upper combustion chamber, the combustion gas is lowered along the peripheral wall of the upper combustion chamber to perform complete combustion in the meantime. As a result, the mixture of the combustible gas and the combustion air generated by the primary combustion burns from the communicating portion where the cross-sectional area connecting the lower combustion chamber and the upper combustion chamber is reduced while burning to the upper combustion chamber. And combusts without forming a dead space in the upper combustion chamber, so that the combustible gas completely burns in the upper combustion chamber, and the harmful substance carbon monoxide becomes carbon dioxide gas, Iokishin is to eliminate the hazard by pyrolysis.

[0020]

FIG. 1 is an explanatory view in cross section showing an example of the incinerator of the present invention. As shown in this figure, the incinerator 1 has a lower combustion chamber 2a and an upper combustion chamber 2b provided at the center thereof.
A refuse supply means 3 for supplying refuse to the incinerator 1 provided on one side of the lower combustion chamber 2a, and a main burner 4 provided on the other side of the lower combustion chamber 2a. A combustion air supply means 5 provided at the bottom of the lower combustion chamber 2a;
An exhaust gas outlet 21 is provided at the bottom of the upper combustion chamber 2b in a horizontal direction from the core. The ceiling portions of the lower combustion chamber 2a and the upper combustion chamber 2b are both set to form a conical shape.

Exhaust gas outlet 2 provided at the bottom of the peripheral wall
Numeral 1 is connected to a flue (not shown) surrounding the incinerator 1 in a ring shape, and the combustion exhaust gas is led out of the system through the ring-shaped flue.

The lower combustion chamber 2a and the upper combustion chamber 2b are communicated with each other by a communicating portion 7 provided at the center thereof in the vertical direction. Also, the lower combustion chamber 2
In addition to the main burner 4, an auxiliary burner 4 a having a small capacity is provided at a position facing the main burner 4.

The dust supply means 3 has an impeller 32 inside.
Are provided, and a dust supply passage 33 that guides refuse sent from the feeder 31 into the incinerator 1. The impeller 32 is configured to rotate around a horizontal axis provided in the feeder 31 by a driving device (not shown), and the refuse D introduced from the upper inlet through the rotation is moved into the lower combustion chamber 2a. It is configured to be introduced into.

The bottom of the incinerator 1 is formed in a mortar shape, and at the bottom, a number of air tubes 51 communicating with a lower manifold 52 are provided in a vertical direction.
An air inlet 53 is provided on one side. The air fine tube 51, the manifold 52, and the air intake 53 form a combustion air supply unit 5.

An incombustible discharge pipe 61 for discharging combustion residues is provided in a hanging state from the center of the bottom of the combustion chamber 2 having a mortar shape. The lower part is connected to an incombustible discharger 62 provided with a spiral feeder inside. A vibrating sieve 63 is connected to the outlet of the incombustible discharger 62, and the sand S sieved by the vibrating sieve 63
Is again supplied from the feeder 31 to the lower combustion chamber 2a,
Used for circulation. The incombustible discharge mechanism 6 is formed by the incombustible discharge pipe 61, the incombustible discharger 62, and the vibrating sieve 63.

In such an incinerator 1, refuse D is fed from a feeder 31 together with sand S as a combustion auxiliary material through an inlet.
And is supplied into the incinerator 1 through the dust supply passage 33 as the impeller 32 rotates. Then, the sand S charged due to the specific gravity difference accumulates at the bottom of the incinerator 1, and the dust D is placed thereon. Then, when combustion air is supplied into the incinerator 1 from an unillustrated blower through the air intake port 53, the manifold 52, and the air capillary 51, it dives between the sand S deposited on the bottom of the upper combustion chamber 2b. And is uniformly dispersed, and is supplied to the dust D on the upper side.

When the main burner 4 is ignited, the sand S
The upper refuse D is thermally decomposed to generate flammable gas, which is mixed with the combustion air to form an air-fuel mixture. The air-fuel mixture rises while burning, passes through the narrow communication portion 7, and becomes The combustion gas becomes a combustion gas in which the neutral gas, the air, and a part of the flame are mixed, and is blown up toward the ceiling of the upper combustion chamber 2b. Then, the air-fuel mixture that has become a flame collides with the ceiling of the upper combustion chamber 2b and turns back. The exhaust gas is discharged outside the system through the exhaust gas discharge port 21.

The main burner 4 is used only in the early stage of combustion, and is used in the lower combustion chamber 2a and the upper combustion chamber 2b.
When the temperature of the inside becomes high and the refuse D itself starts self-combustion, the main burner 4 is stopped, the auxiliary burner 4a having a small capacity is ignited, and only the auxiliary burner 4a is used to incinerate the incinerator 1.
The refuse D inside is burned.

As described above, in the combustion furnace according to the present invention, the mixture of the combustible gas and the combustion air generated from the refuse D generated in the lower combustion chamber 2a is temporarily removed from the lower combustion chamber 2a.
And is ejected to the upper combustion chamber 2b through the communication part 7 which is smaller than the surrounding area. This high velocity gas flow draws in ambient gas, which promotes mixing of the combustible gas with the combustion air. Further, since the upper combustion chamber 2b is provided with an exhaust gas outlet 21 on the inner peripheral wall surface at the bottom thereof,
The air-fuel mixture jetted into the upper combustion chamber 2b collides with the ceiling of the upper combustion chamber 2b and is reflected therefrom. Is discharged outside the system from the exhaust gas discharge port 21. Therefore, in the meantime, the mixture is sufficiently homogeneously mixed with the longer residence time of the mixture in the furnace than before, so that the combustion is completely performed and the carbon monoxide is converted into carbon dioxide. In addition, since dioxin is almost completely thermally decomposed and these harmful substances are not discharged outside the furnace, it is extremely advantageous in preventing environmental pollution caused by exhaust gas discharged from the incinerator.

A comparison test was conducted between the conventional incinerator 1 'shown in FIG. 3 and the incinerator 1 of the present invention shown in FIG. The waste disposal capacity of the incinerators is 100 t / day. And
Carbon monoxide was used as an indicator of harmful substances emitted from the incinerator, and its concentration was measured. As a result of the measurement, in the conventional incinerator 1 ', the carbon monoxide concentration was 75
In contrast, in the incinerator 1 according to the present invention, in which the combustion chamber 2 was divided into upper and lower parts, the carbon monoxide concentration was 9 ppm.
ppm. This also indicates that the present invention is extremely effective in reducing harmful substances discharged from the incinerator.

FIG. 2 is an explanatory view in cross section showing another example of the incinerator of the present invention. In the case of this example, a secondary air introduction hole 22 is provided in the communication portion 7, and secondary air is introduced from here separately from the combustion air introduced from the bottom of the lower combustion chamber 2 a via the combustion air supply means 5. Is done. Therefore, the mixture of the air and the combustible gas generated from the refuse D proceeds more favorably, and the mixture is burned more favorably in the upper combustion chamber 2b. Emission of substances can be more effectively suppressed.

As described above, the incinerator according to the present invention is obtained by dividing the conventional incinerator 1 'into upper and lower parts to form the lower combustion chamber 2a and the upper combustion chamber 2b, which are connected by the communication part 7. There is a method of reducing the emission of harmful substances from the incinerator by mixing the combustible gas thermally decomposed in the lower combustion chamber 2a and the combustion air into the upper combustion chamber 2b through the communication section 7 to perform upper combustion. Since the air-fuel mixture is completely burned in the chamber 2b, it is not necessary to newly install and add another equipment to reduce the emission of harmful substances, but to make the equipment scale almost the same as the conventional one. It is also advantageous from the viewpoint of capital investment.

In particular, as in the example shown in FIG.
a and the upper combustion chamber 2b, the effect of mixing the combustible gas and air is increased by introducing the secondary air from the communicating portion 7 connecting the upper combustion chamber 2b to the upper combustion chamber 2b. It can be set small, which is advantageous because the incinerator 1 can be made compact.

[0034]

As described above, in the incinerator according to the present invention, the upper combustion chamber and the lower combustion chamber are provided with a communicating portion at the center of the upper combustion chamber and the lower combustion chamber. Since the combustion air supply means, the refuse supply means, and the burner are provided, and a plurality of exhaust gas discharge ports are provided at the bottom of the peripheral wall of the upper combustion chamber, the refuse introduced into the lower combustion chamber is burner and high temperature. Is heated by the sand that has been heated to generate pyrophoric gas by pyrolysis, and this combustible gas burns by obtaining combustion air supplied from the lower combustion chamber,
The gas flow is injected into the upper combustion chamber through the communicating part, collides with the ceiling and is radiated, hangs down the inner peripheral wall, burns all over the upper combustion chamber, and burns the upper combustion chamber. It is discharged outside the furnace from a discharge port provided at the bottom of the peripheral wall of the chamber.

As described above, the air-fuel mixture of combustible gas and combustion air is injected into the upper combustion chamber from the communication section having a reduced cross-section connecting the lower combustion chamber and the upper combustion chamber, and the surrounding gas is discharged. Microscopic mixing occurs due to the velocity difference from the flow, and the mixing is further promoted by collision with the ceiling, and combustible gas is formed without forming a dead space in the upper combustion chamber. When completely burned, carbon monoxide, which is a harmful substance, becomes carbon dioxide gas, and dioxin is thermally decomposed to eliminate its harmfulness.

Further, if a secondary air supply hole is provided in the communication portion and the combustion air is supplied from the secondary air supply hole into the furnace, the mixing of the combustible gas and the combustion air further progresses. It is possible to reliably suppress their discharge to the outside of the furnace.

According to the method for reducing the emission of harmful substances from an incinerator according to the present invention, refuse is supplied to the lower combustion chamber, and primary combustion is performed in the lower combustion chamber by supplying combustion air from the bottom. After the combustion gas is ejected from the communication section into the upper combustion chamber and collides with the ceiling of the upper combustion chamber, the combustion gas is lowered along the peripheral wall of the upper combustion chamber to perform complete combustion therebetween. Has been
The mixture of the combustible gas and the combustion air generated by the primary combustion is ejected into the upper combustion chamber from the communicating portion having a reduced cross-sectional area connecting the lower combustion chamber and the upper combustion chamber while burning, and into the upper combustion chamber. Because it burns without forming a dead space, combustible gas is completely burned in the upper combustion chamber, carbon monoxide, which is a harmful substance, becomes carbon dioxide, and dioxin is thermally decomposed to eliminate its harmfulness Can be.

As described above, the use of the incinerator of the present invention and the method for reducing the emission of harmful substances from the incinerator can effectively suppress the emission of dioxin from the incinerator, which has been particularly problematic in the past. This is extremely advantageous in preventing pollution.

[Brief description of the drawings]

FIG. 1 is an explanatory view in cross section showing an example of an incinerator of the present invention.

FIG. 2 is an explanatory view in cross section showing another example of the incinerator of the present invention.

FIG. 3 is an explanatory view in cross section illustrating a conventional incinerator.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1, 1 'Incinerator 2, 2' Combustion chamber 2a Lower combustion chamber 2b Upper combustion chamber 21, 21 'Exhaust gas outlet 22, 22' Secondary air introduction hole 3 Waste supply means 31 Feeder 32 Impeller 4 Main burner 4a Auxiliary burner Reference Signs List 5 combustion air supply means 51 air narrow tube 52 manifold 53 air intake 6 noncombustible discharge mechanism 61 noncombustible discharge pipe 62 noncombustible discharger 7 communication section

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) F23G 5/00 F23G 5/16 F23G 5/027 F23G 5/44 F23L 17/12

Claims (3)

(57) [Claims] 1. An incinerator having a combustion air supply means at a bottom portion and a combustion chamber having a refuse supply means and a burner, wherein the combustion chamber is divided into an upper combustion chamber and a lower combustion chamber. The upper combustion chamber and the lower combustion chamber are provided at their center with a communicating portion where they communicate with each other. The lower combustion chamber is provided with combustion air supply means, refuse supply means, and a burner. An incinerator, characterized in that a plurality of exhaust gas outlets are provided at the bottom of the peripheral wall of the chamber. 2. The incinerator according to claim 1, wherein a secondary air supply hole is provided in the communication portion. 3. A method for incinerating refuse using a combustion chamber which is divided into an upper combustion chamber and a lower combustion chamber and which are communicated by a communicating portion having a reduced cross-sectional area, wherein the lower combustion chamber is provided. The primary combustion is performed in the lower combustion chamber by supplying garbage to the lower part of the upper combustion chamber by supplying combustion air from the bottom of the lower combustion chamber, and the combustion gas is ejected from the communication part to the upper combustion chamber to be provided on the ceiling of the upper combustion chamber. After the collision, it is lowered along the peripheral wall of the upper combustion chamber to perform complete combustion in the meantime, and the exhaust gas is discharged from a plurality of exhaust gas exhaust ports provided at the bottom of the peripheral wall of the upper combustion chamber. To reduce the emission of harmful substances from incinerators.