JPH07243630A - Fluidized bed type incinerator - Google Patents

Abstract

PURPOSE:To provide an incinerator of the fluidized bed type which enables decreasing unburnt combustibles such as carbon monoxide and hydrocarbon by substantially accelerating the mixing of combustible gases with air for combustion. CONSTITUTION:In the wall of a void part of column 3 in downstream of a fluidized bed 2 there are provided a plurality of secondary air-feeding nozzles 10 which are unsymetrical with respect to all virtual axes on a plane consisting of one and the same horizontal cross section so as to form a film of secondary air in the direction of a horizontal cross section in the void part of column 3 and make rising combustible gases mix with secondary air 13 with good efficiency. Since the material for incineration 11 undergoes thermal decomposition immediately after its feeding into the incinerating furnace, positioning of a nozzle 10 closest to the material-feeding port 5 on the wall and another at a position opposed thereto on the wall enables to disperse the highly thick combustible gases on the side of the material- feeding port 5. By inclining downward the direction in which the air is blown in from the nozzles 10 the combustible gases can be dispersed immediately above the fluidized bed 2, a spiral flow 17 can be vertically produced inside the void part of column 3, and the time for which the combustible gases stay therein can be extended with the result of increasing the mixing ratio of the combustible gases with air for combustion.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fluidized bed type incinerator used for incineration of municipal solid waste, and more particularly to a fluidized bed type incinerator capable of reducing unburned components such as carbon monoxide and hydrocarbons and dioxin emissions. Regarding incinerator.

[0002]

2. Description of the Related Art Generally, a fluidized bed type incinerator is used in addition to a stoker type incinerator for incinerating municipal solid waste. 8 and 9 (a sectional view taken along the line aa of FIG. 8 (FIG. 9A)) and FIG.
A cross-sectional view taken along the line bb of FIG.
1 shows an example of a fluidized bed type incinerator according to the prior art described in Japanese Patent Publication No. 140501, in which an incinerator body 1 is composed of a fluidized bed 2 and an empty tower section 3. The combusted material 11 supplied into the furnace from the combusted material supply port 5 is fluidized together with the fluidized medium 8 by the primary air 12 supplied from the diffuser pipe 9 installed in the fluidized bed 2 below the fluidized bed 2. , Burned and / or heat dispersed. Combustible gas such as decomposed gas generated at this time is mixed with the primary air 12 blown over the fluidized bed 2 in the empty column section 3 and the secondary air 13 supplied to the empty column section 3 and burned, and then the outlet of the incinerator. It is discharged from 7.

Combustible substances containing a large amount of volatile components, such as municipal waste,
Most of the gas is vaporized by thermal decomposition in the fluidized bed 2 and burned in the empty column section 3, so it is necessary to sufficiently mix the combustible gas and air in the empty column section 3. When the combustible gas and the air are not sufficiently mixed, unburned components such as carbon monoxide and hydrocarbons are discharged together with the exhaust gas. Further, unburned matter in the exhaust gas reacts with chlorides such as hydrogen chloride to generate dioxin. In order to solve the above problem, the vertical central axis of the empty column portion 3 is eccentric from the central axis of the fluidized bed 2,
As shown in FIG. 9, the secondary air supply nozzle 10 is provided on the wall surface of the empty column part 3 so as to form a horizontal swirl flow 14 in the empty column part 3.
Is installed to promote the mixing of combustible gas and combustion air. However, even with the above-mentioned conventional technique, when the combustible gas and the combustion air in the empty column section 3 are insufficiently mixed, particularly when the supply amount of the combustible material is increased and a large amount of combustible gas is suddenly generated, Combustible gas blows through, and a large amount of unburned carbon monoxide, hydrocarbons, etc. is discharged from the incinerator. The reason is that, as shown in FIG. 10A, the horizontal swirl flow 14 of the secondary air 13 causes combustion of combustible gas in the central portion of the horizontal cross section (cross section taken along the line aa of the empty tower section aa in FIG. 10B). A high-concentration region A is generated, and as shown in FIG. 10 (b), an upward flow B of a portion having a high concentration of combustible gas is generated in the vertical direction of the incinerator body 1, and mixing with the secondary air 13 occurs. Insufficient combustion will result in insufficient combustion.

Further, as shown in FIG. 11 (FIG. 11A is a schematic vertical sectional view of the incinerator, and FIG. 11B is a sectional view taken along line aa of FIG. 11A), the incinerator is shown. A structure in which the vertical central axis of the empty column section 3 of the main body 1 is eccentric from the central axis of the fluidized bed 2 and the empty column section 3 is provided with a secondary air supply nozzle 10 for blowing secondary air 13 downward and an auxiliary burner 16. Japanese Patent Laid-Open No. 3-1
It is disclosed in Japanese Patent No. 25808. In the invention described in the publication, the upward flow containing the combustible gas from the fluidized bed 2 is the empty tower section 3
At the secondary air 1 blown out from the downward nozzle 10
3 and the auxiliary combustion burner 16 are re-combusted to reduce the amount of unburned gas. In the present invention, the upward flow containing the combustible gas from the fluidized bed 2 is eccentrically supplied to the empty column section 3, so that the mixing with the secondary air 13 supplied in the fluidized bed 2 is promoted, and the empty column is Since the secondary air supply nozzle 10 is directed downward in the section 3, there is an element that causes the upward flow containing the combustible gas to generate a vertical swirl flow. However, as shown in FIG. 11B, since the secondary air supply nozzle 10 of the empty column section 3 is provided symmetrically with respect to the virtual axis line in the horizontal cross-sectional direction, the blown secondary air 13 is Empty tower 3
They collide with each other in the central part and cannot reach the other side of the furnace. Further, as shown in FIG. 11B, a gap C may be formed between the secondary air blowing regions, and the upward flow containing the combustible gas may pass through the gap C and not be mixed with air.

In addition, in Japanese Patent Laid-Open No. 61-101709, as shown in FIG. 12, a secondary downward facing wall surface of the incinerator body 1 immediately below the empty tower outlet 6 in which the passage of the empty tower 3 is narrowed. An example in which a plurality of air supply nozzles 10 are tilted downward and are attached at equal intervals, or in Japanese Utility Model Publication No. 61-37956, as shown in FIG. An example is disclosed in which the secondary air supply nozzle 10 facing downward is provided only on one side wall surface immediately below the tower outlet 6. However, in the case shown in FIG. 12, since the plurality of secondary air supply nozzles 10 are symmetrically arranged, the upward swirl flow containing the combustible gas in the vertical direction does not occur, and the secondary air 13 and the combustible gas are not generated. 13 is not sufficiently mixed, and in the case shown in FIG. 13, the secondary air supply nozzle 10 is provided only on the side wall surface of one incinerator body 1, so that FIG.
As shown in (a sectional view taken along the line aa of FIG. 11A),
A blow-through portion C of the ascending flow containing the combustible gas is generated.

[0006]

As described above, the above-mentioned conventional technique has a problem in that a region where the secondary air and the combustible gas are not sufficiently mixed occurs. An object of the present invention is to provide a fluidized bed incinerator capable of sufficiently promoting the mixing of combustible gas and combustion air to reduce unburned carbon monoxide, hydrocarbons and the like.

[0007]

The above objects of the present invention can be achieved by the following constitutions. That is, in a fluidized bed type incinerator having a fluidized bed and a hollow tower section, a plurality of secondary air supply nozzles installed on the wall surface of the empty tower section are formed on a plane of the same horizontal cross section of the empty tower section. It is a fluidized bed incinerator that is asymmetric with respect to any virtual axis. In the fluidized bed type incinerator of the present invention, the secondary air supply nozzle is installed on the wall surface closest to the combustion object supply port of the empty tower part and the wall surface facing the wall surface, and the air blowing direction of the secondary air supply nozzle is set. Configuration that installs downwards, configuration that installs part of the secondary air supply nozzle downwards near the exit of the empty column part, and the vertical center axis of the fluidized bed and the vertical center axis of the empty column part are eccentric to each other. It can be configured. Further, the fluidized bed type incinerator of the present invention can be applied to a fluidized bed type incinerator having a fluidized bed and a hollow tower section, or a fluidized bed type incinerator having a post-combustion chamber after the empty column section of the incinerator.

[0008]

Since the plurality of secondary air supply nozzles are asymmetric with respect to any virtual axis formed on the plane formed by the same horizontal cross section of the empty column portion, as shown in FIG. 5 (FIG. 5A is incinerated). As shown in a vertical sectional simplified view of the furnace body 1 and FIG. 5B is a horizontal sectional simplified view of line aa in FIG. 5A, the secondary air supplied from a certain secondary air supply nozzle 10 is supplied. 13 is a secondary air supply nozzle 1 installed on the wall surface of the incinerator body 1 facing
The secondary column 13 can reach the opposing wall surface part with almost no collision with the secondary air 13 supplied from 0, and a plurality of secondary air supply nozzles as shown in FIG. Since the film D is formed by the secondary air 13 blown out from 10, the combustible gas that rises in the vertical direction always comes into contact with the secondary air 13 and is efficiently mixed.

Further, since the burned material is thermally decomposed immediately after being supplied into the incinerator, the combustible gas has a high concentration on the side where the burned material supply port 5 is installed, but the secondary air supply nozzle Since 10 is installed on the wall surface of the empty tower portion 3 closest to the burned material supply port 5 and the wall surface facing the wall surface, it is possible to disperse the high-concentration combustible gas on the burned material supply port 5 side. it can. Further, since the air blowing direction of the secondary air supply nozzle 10 is set to face downward,
As shown in (a), the combustible gas can be dispersed directly above the fluidized bed 2, and a vertical swirl flow 17 is generated in the empty column section 3 shown in FIG. As the combustible gas increases, the combustible gas is efficiently mixed with the combustion air.

Further, as shown in FIG. 7, since a part of the secondary air supply nozzle 10 is installed downward near the empty column section outlet 6 at the empty column section outlet 6, a downward air flow is generated. The swirling of the swirling flow 17 in the vertical direction is promoted,
In addition, the combustible gas flowing toward the empty tower section outlet 6 is prevented from blowing through. Therefore, the unburned gas stays in the empty column section 3 for a long period of time and is sufficiently mixed with oxygen during that time, so that combustion can be promoted. In this way, by dispersing the combustible gas, incomplete combustion due to a partial air shortage is prevented, and the combustion is promoted by efficiently mixing the combustible gas and the combustion air. The amount of fuel emission can be reduced. Further, it is possible to reduce the emission amount of dioxins generated by the reaction of unburned components in exhaust gas with chlorides such as hydrogen chloride.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. 1 is a schematic vertical sectional view of a fluidized bed incinerator according to the present invention, and FIG. 2 is a horizontal sectional arrow view (FIG. 2 (a)) of FIG. Sectional view (Fig. 2
(B)). In FIG. 1, an incinerator body 1 of a fluidized bed type incinerator is configured such that a fluidized bed 2, an empty column portion 3 and a post combustion chamber 4 are sequentially stacked, and the lower portion of the incinerator is not shown. There is a device for taking out incombustibles. In the empty column section 3, the vertical central axis of the empty column section 3 is arranged at a position eccentric from the vertical central axis of the fluidized bed 2 in order to promote mixing of the gas in the column. The burned material 11 supplied into the furnace from the burned material supply port 5 installed on the wall surface of the incinerator is generated by the primary air 12 supplied from a number of air diffusers 9 installed in the fluidized bed 2 below the fluidized bed 2. As it is fluidized with the fluidized medium 8 such as silica sand, it is vaporized by thermal decomposition. Combustible gas such as cracked gas generated at this time is generated in the fluidized bed 2 in the empty column section 3 and the post combustion chamber 4.
After the primary air 12 blown upward and the secondary air 13 supplied from the secondary air supply nozzle 10 installed in the two stages of the empty column part 3 and the empty column part outlet 6 are mixed and burned, the incinerator exit It is discharged from 7.

Since the secondary air supply nozzle 10 is installed asymmetrically on the wall surface of the incinerator facing the secondary air flow nozzle 10 as shown in FIG. 2, the secondary air flow 15 is shown in a horizontal cross section of the empty column section 3 as shown in FIG. A film D of the next air 13 is formed. Further, since the secondary air supply nozzle 10 is installed downward on the wall surface side having the burned material supply port 5 and the wall surface side opposite thereto as shown in FIG. The stream 17 is generated, the combustible gas and the combustion air are efficiently mixed, and combustion is promoted. Thus, when the combustible gas and the combustion air are mixed in the empty column section 3, especially the supply amount of the combustible material is increased, and when a large amount of the combustible gas is suddenly generated, temporary carbon monoxide, hydrocarbons, etc. It is possible to suppress the discharge of unburned components. The example shown in FIG. 3 is an example in which a part of the secondary air supply nozzle 10 is installed in front of the outlet 6 of the empty column part 3, and in this case also, when it is installed at the empty column part outlet 6 as shown in FIG. The vertical swirl flow 17 is promoted in the same manner as the
It has the effect of preventing blow-through of combustible gas into the room.

FIG. 4 shows an installation example of the secondary air supply nozzle 10 in an incinerator in which the empty column section 3 is a cylindrical type, and the present invention does not limit the shape of the empty column section 3. As described above, the present invention has been described with the fluidized bed incinerator having the post combustion chamber 4 and the two-stage secondary air supply nozzle 10 installed as an example, but the present invention does not have the post combustion chamber 4. It can also be applied to an incinerator or an incinerator equipped with one or three or more secondary air supply nozzles 10. When a plurality of secondary air supply nozzles 10 are installed, any one or more secondary air supply nozzles 10 are installed.
Is installed on the wall surface closest to the burned material supply port 5 and on the wall surface facing the wall surface, and any one or more of the secondary supply nozzles 10 may be installed downward. The secondary air supply nozzle 10 is preferably included in this.

[0014]

According to the fluidized bed type incinerator of the present invention, the combustion of the combustible gas is promoted by efficiently mixing the combustible gas and the combustion air, and unburned components such as carbon monoxide and hydrocarbons are combusted. The amount of emission can be reduced. Further, it is possible to reduce the emission amount of dioxins generated by the reaction of unburned components in exhaust gas with chlorides such as hydrogen chloride.

[Brief description of drawings]

1 is a schematic view of a vertical cross section of a fluidized bed incinerator according to an embodiment of the present invention.

2 is a sectional view taken along line aa of FIG. 1 (FIG. 2 (a)), bb
FIG. 3 is a schematic view of a line cross section (FIG. 2 (b)).

FIG. 3 is a schematic view of the vicinity of the empty column outlet of a vertical cross section of a fluidized bed incinerator according to an embodiment of the present invention.

FIG. 4 is a schematic view of a horizontal section of a hollow tower portion of a cylindrical fluidized bed incinerator according to an embodiment of the present invention.

FIG. 5 is a diagram illustrating a flow of gas in a fluidized bed incinerator according to an embodiment of the present invention.

FIG. 6 is a diagram illustrating a flow of gas in a fluidized bed incinerator according to an embodiment of the present invention.

FIG. 7 is a diagram for explaining the flow of gas in the furnace near the outlet of the empty tower part of the fluidized bed incinerator according to the embodiment of the present invention.

FIG. 8 is a schematic view of a vertical section of a fluidized bed incinerator according to the prior art.

9 is a schematic diagram of a cross section taken along the line aa (FIG. 8A) and a cross section taken along the line bb (FIG. 9B) of FIG.

FIG. 10 is a diagram illustrating a flow of gas in a furnace of a conventional fluidized bed incinerator.

FIG. 11 is a diagram illustrating a flow of gas in a furnace of a fluidized bed incinerator according to a conventional technique.

FIG. 12 is a diagram illustrating a flow of gas in a furnace of a fluidized bed incinerator according to a conventional technique.

FIG. 13 is a diagram illustrating a flow of gas in a furnace of a fluidized bed incinerator according to a conventional technique.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Incinerator main body, 2 ... Fluidized bed, 3 ... Empty tower part, 4 ... Post-combustion chamber, 5 ... Combustion material supply port, 6 ... Empty tower part exit, 7 ... Incinerator exit, 8 ... Fluid medium, 9 ... Air diffuser, 10 ... Secondary air supply nozzle, 11 ... Combustion object, 12 ... Primary air, 13 ... Secondary air, 15 ... Secondary air flow, 14, 17 ... Swirling flow

Claims (5)

[Claims] 1. In a fluidized bed type incinerator having a fluidized bed and a superficial part, a plurality of secondary air supply nozzles installed on the wall surface of the superficial part are on a plane formed by the same horizontal cross section of the superficial part. A fluidized bed incinerator characterized by being asymmetric with respect to any virtual axis formed. 2. The fluidized bed incineration system according to claim 1, wherein the secondary air supply nozzles are installed on the wall surface of the empty tower portion that is closest to the combustion object supply port and the wall surface facing the wall surface. Furnace. 3. The fluidized bed incinerator according to claim 1, wherein the secondary air supply nozzle is installed so that the air blowing direction is downward. 4. The fluidized bed incinerator according to any one of claims 1 to 3, wherein a part of the secondary air supply nozzle is installed downward near the outlet of the empty column section. 5. The fluidized bed incinerator according to claim 1, wherein the vertical center axis of the fluidized bed and the vertical center axis of the empty column portion are eccentric to each other. .