JPH0942636A - Fluidized bed incinerator using high temperature air - Google Patents

Abstract

PROBLEM TO BE SOLVED: To achieve a lower security cost and a longer life of an air scattering device of a fluidized bed incinerator using high temperature air to be blown into the body of the furnace. SOLUTION: An air scattering device which is provided on a furnace bottom of the body 1 of a furnace to support a sand layer 6 and has a plurality of air scattering nozzles 4 for blowing high temperature air from an wind box 7 formed below the furnace bottom in the sand layer 6 and an unburned matter withdrawal port 3 at the center part lower than the outer circumference part is constituted of an orifice plate 2 alone where air blowoff pipes 4a of the air scattering nozzles 4 are welded to blow the high temperature air horizontally and made up of a heat resistant/wear resistant metal plate. This achieves a lower security cost required for a refractory castable and a higher durability of a fluidized bed incinerator because the expansion of the orifice plate 2 is unbound. It is true that a thin static sand layer 6a is formed on the top surface of the orifice plate 2. But the sand idler will not block the fluidization of the sand in the sand layer 6 and the movement of unburned matters in the direction of an unburned matter withdrawal port 3 thereby enabling stable movement thereof for a long period of time.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a technical field of a fluidized bed incinerator using high-temperature hot air for incinerating sludge, municipal waste, or other incineration objects.

[0002]

2. Description of the Related Art A sand layer is supported on the bottom of a furnace body of a fluidized bed incinerator for incinerating sludge, municipal solid waste, or other incineration material, and air is blown into the sand layer to cause convection flow of the sand layer. At the same time, there is provided an air dispersion device having a plurality of air dispersion nozzles that function to burn the material to be incinerated that is put into the sand layer. Such an air disperser is disclosed, for example, in Japanese Utility Model Publication No. 60-9558 and Japanese Patent Application Laid-Open No. 3-122411.

First, the fluidized bed incinerator according to the conventional example 1 disclosed in Japanese Utility Model Publication No. 60-9558 is shown in a sectional view of FIG. 4 (a) and an enlarged perspective view of a portion C of FIG. 4 (a). Figure 4
Explaining with the same reference numerals and the same names described in the specification with reference to (b), the air dispersion device 4 that is an air dispersion plate is provided on the bottom surface inside the furnace body 1 in an inclined manner. ing. An air chamber 5 is provided below the air dispersion device 4.
Is formed so as to take in the flow-purpose / combustion air guided from the air inlet 6. This air disperser 4
As shown in FIG. 3 (b), a floor plate 8 and a plurality of air dispersion blocks 9 are combined to form a furnace bottom, and a perforated plate 10 (orifice plate) is provided below the furnace bottom. .
An exhaust gas outlet 3 is provided on the upper part of the furnace body 1,
A discharge port 7 for taking out incombustibles and the like is provided at the lowest position of the air dispersion device 4. The sand layer 18 is supported by the air dispersion device 4. The floor plate 8 and the air dispersion block 9 are made of a refractory material such as high-strength wear-resistant castable containing stainless fiber. The bottom surface is kept flush with the bottom surface of the floor plate 8, but the upper portion projects from the floor plate 8 and penetrates the side surface 11 thereof to provide an air outlet 12 in a substantially horizontal direction. From the bottom of the air dispersion block 9, the air outlet 1
A passage 13 communicating with 2 is provided. This perforated plate 1
0 is two perforated single plates 1 supported in parallel with a gap.
The upper porous single plate 14 is provided in contact with the air dispersion block 9 and the bottom surface of the floor plate 8, and the small hole 16 is provided immediately below the passage 13. The small holes 17 of the lower porous single plate 15 are arranged so as not to overlap the small holes 16 in the vertical direction.

Next, the fluidized bed incinerator according to the conventional example 2 disclosed in JP-A-3-122411 will be described with the same reference numerals and the same names described in the same specification. The bottom of the furnace is shown in FIG.
As shown in FIG. 5, an air dispersion plate 3 (air dispersion device) formed in a mortar shape and having an incombustibles extraction pipe 9 in the center is provided. As well understood from the figure, the air dispersion plate 3 is composed of an upper refractory material and an orifice plate made of a metal plate that supports the refractory material. In addition,
Reference numerals 4 and 5 in which the lower end side penetrating the orifice plate is fixed to the orifice plate and the upper side penetrates the refractory material.
Is an air dispersion nozzle for blowing the flowing and combustion air in the wind box 10 provided on the lower side of the furnace body 1 into the sand layer 8 supported by the air dispersion plate 3.

Therefore, in any of the above-mentioned air dispersion devices and air dispersion plates for fluidized bed incinerators, air for fluidization and combustion is blown from the air box into the sand layer. As a result, when the material to be incinerated is added to the flowing sand layer, the material to be incinerated is dispersed / crushed, pyrolyzed, and incinerated.

[0006]

As described above, the air dispersing device of the fluidized bed incinerator is composed of an orifice plate made of a metal plate and a refractory castable provided inside the orifice plate. The refractory castables are provided on the upper surface of the orifice plate in order to smoothly discharge the incombustible material and to prevent the temperature of the sand layer reaching 700 ° C. from being directly transmitted to the orifice plate.
By the way, the orifice plate is thermally expanded by the temperature of the fluidizing / combusting air introduced into the wind box. As in the case of conventional fluidized bed incinerators, the temperature of the fluidizing and combustion air is 100 ° C.
If the degree of expansion is small, the expansion amount of the orifice plate is small, for example,
When the furnace diameter is 1750 mm, it is about 3 mm, and there is no particular problem. However, the following problems occur depending on the temperature of the fluidizing / combusting air introduced into the wind box.

That is, in a fluidized bed incinerator, such as a sludge incinerator, in which auxiliary fuel is injected to maintain the temperature of the sand layer, the energy stored in the exhaust gas is utilized from the viewpoint of saving auxiliary fuel (energy saving), and the temperature gradually increases. The flow and combustion air of is introduced into the wind box. In recent years, for example, 6
Flowing and combustion air having a temperature as high as 50 ° C may be used. When a high temperature fluidizing / combusting air as high as 650 ° C. is introduced into the wind box, the expansion amount of the orifice plate becomes large, for example, 20 mm when the furnace diameter is 1750 mm. On the other hand, since the thermal expansion amount of the refractory material is only about 1 mm, the refractory material is damaged due to the difference in expansion amount between the orifice plate and the refractory material, or the expansion of the orifice plate is restricted by the refractory material and High stress occurs,
Repeated generation of high stress causes cracks in the fixed portion between the furnace body and the orifice plate, resulting in a problem that the life of the fluidized bed incinerator is shortened.

If the air disperser is constituted by only the orifice plate, it is considered that the above problems can be solved. However, this configuration is effective for a fluidized bed incinerator having no incombustibles outlet, and is not suitable for a fluidized bed incinerator having an incombustibles outlet. That is, the air dispersion nozzle normally projects upward from the orifice plate,
This is because incombustibles cannot be discharged. When the air dispersion device is constituted by only the orifice plate, a static sand layer is formed on the upper surface of the orifice plate, and this static sand layer suppresses direct heat transfer of high temperature sand up to 700 ° C. to the orifice plate.

Therefore, an object of the present invention is to provide a fluidized bed incinerator which solves the above-mentioned problems, reduces maintenance costs, and uses high temperature air having excellent durability.

[0010]

In order to solve the above problems, the means adopted by the air dispersing device of the fluidized bed incinerator using high temperature air according to claim 1 of the present invention is provided at the bottom of the furnace body. A plurality of air dispersions for supporting a sand layer, convectively flowing the sand layer from a wind box formed under the furnace bottom in the sand layer, and blowing hot air for burning the incineration object. An air dispersion device with a nozzle and an outlet for incombustibles at the center lower than the outer periphery is connected to the air outlet pipe of the air dispersion nozzle that blows high-temperature air in the horizontal direction. It is characterized in that only the orifice plate made of an abradable metal plate is used.

The means adopted by the air dispersing device of the fluidized bed incinerator using high temperature air according to claim 2 of the present invention is:
High temperature air for supporting a sand layer provided on the bottom of the furnace body, convectively flowing the sand layer from a wind box formed below the bottom of the furnace in the sand layer, and burning the incineration object A plurality of air dispersion nozzles for blowing air, and an air dispersion device in which a non-combustible matter outlet is provided in a central portion lower than the outer peripheral portion, and an air outlet pipe of the air dispersion nozzle for horizontally injecting high temperature air. Of the heat-resistant and wear-resistant metal plate, which is formed into a concave concave convex shape.

Further, the means adopted by the air dispersing device of the fluidized bed incinerator using high temperature air according to claim 3 of the present invention is:
The fluidized bed incinerator using high temperature air according to claim 1 or 2, wherein a sand flow prevention dam made of a heat-resistant and wear-resistant metal plate surrounding the incombustibles outlet is provided on the upper surface of the orifice plate. It is a feature.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION In the present invention, the orifice plate is heat-resistant.
If it is formed from a wear-resistant metal plate and the amount of protrusion of the air dispersion nozzle to the upper side of the orifice plate is reduced, the flow of the sand layer is not obstructed and a sand stop layer can be formed on the upper surface of the orifice plate. We believe that we can realize a fluidized bed incinerator with a function of moving incombustibles to the incombustibles discharge port and having a long-life life, and we have installed a fluidized bed incinerator at the bottom of the furnace body to support the sand layer. , A plurality of air dispersion nozzles for blowing convectional flow of the sand layer from a wind box formed on the lower side of the furnace bottom in the sand layer and blowing high temperature air for burning the incineration object, and the outer circumference An air dispersion device with a non-combustible material outlet provided in the center lower than the center part, an orifice consisting of a heat-resistant and wear-resistant metal plate, to which the air blow-out pipe of the air dispersion nozzle for blowing high-temperature air horizontally is joined. Board only In which was formed.

[0014]

EXAMPLE A fluidized bed incinerator using high-temperature hot air according to Example 1 of the present invention will be described below with reference to a cross-sectional view in FIG.
The description will be made with reference to FIG. 1A and FIG. 1B which is an enlarged view of a portion A of FIG.

That is, reference numeral 1 shown in FIG. 1 (a) is a furnace body of a fluidized bed incinerator having a refractory material 8 stretched on its inner wall, and a sand layer 6 is supported on the furnace bottom of the furnace body 1. A shallow mortar-shaped orifice plate 2 having an incombustibles outlet 3 for extracting incombustibles is provided at the center of the lowest position. The orifice plate 2 is formed of a heat-resistant and wear-resistant metal plate made of, for example, a heat-resistant alloy such as Incoloy with a cobalt-based alloy deposited thereon. It is provided. On the lower side of the furnace bottom, there is formed a wind box 7 into which high temperature air of 650 ° C., for example, flows in from an air inlet (not shown). Since the temperature of the high temperature air is obtained by the temperature of the exhaust gas of the fluidized bed incinerator, it is low at the time of starting the operation of the fluidized bed incinerator, but it is gradually increased to 650 when the stable operation state is reached.
It can be increased to as high as ℃.

The air dispersion nozzle 4 has an orifice plate 2
And is horizontally joined by welding. This air dispersion nozzle 4 has an outlet for blowing out high-temperature air toward the center of the furnace body 1, has a cobalt sprayed layer 4c (wear-resistant layer) on the upper peripheral surface on the side of the sand layer 6, and has a wind box 7 It is composed of an air blow-out pipe 4a having a closed inside protruding side, and an air inflow pipe 4b projecting downward from the air blow-out pipe 4a and into which hot air in the wind box 7 flows. Both the air outlet pipe 4a and the air inlet pipe 4b are made of the same material as the orifice plate 2. The cobalt sprayed layer 4c suppresses the abrasion of the air blow-out pipe 4a due to the sand of the sand layer 6 flowing convectively.

Therefore, the high temperature air flowing from the inside of the wind box 7 into the air inflow pipe 4b is blown out from the air blowing pipe 4a toward the center of the furnace body 1 and is blown out by the high temperature air to form the sand layer 6
Sand flows upward in the central portion of the orifice plate 2, and then horizontally flows toward the inner wall of the furnace body 1. Then, the inner wall of the furnace body 1 causes a downward flow, and the orifice plate 2
As a result, convective flow occurs, as if flowing in the direction of the incombustibles outlet 3. When incinerated substances such as sludge and municipal waste are put into the convectively flowing sand layer 6, the incinerated substances are dispersed / crushed, pyrolyzed and incinerated, and the incombustibles convectively flow. The sand in the sand layer 6 is carried to the side of the incombustibles outlet 3 and discharged from the incombustibles outlet 3 to the outside of the system.

Incinerators such as sludge and municipal waste are incinerated in this way, but when convection flow of sand in the sand layer 6 occurs,
As shown in FIG. 1 (a), since a thin static sand layer 6a is formed along the upper surface of the orifice plate 2, the sand layer 6 which is convectively flown even if it is not covered with the refractory castable as in the conventional case. High temperature is not transmitted directly, and the orifice plate 2
Since only a part of the air blow-out pipe 4a of the air dispersion nozzle 4 is projected on the upper surface of the non-combustible material, since the projecting portion is horizontal, the incombustible material is not obstructed from moving obliquely downward. Is discharged from the incombustibles outlet 3 without any trouble.

In order to effectively form the stationary sand layer 6a without disturbing the convective flow of the sand layer 6, it is preferable that the inclination angle of the orifice plate 2 be about 15 °. Also,
Even if the stationary sand layer 6a flows temporarily, the orifice plate 2 wears. However, as described above, since the orifice plate 2 is made of a heat-resistant and wear-resistant metal plate, its durability is practical. It is enough.

On the other hand, the orifice plate 2 has at least 650.
Although it is exposed to high temperature air having a temperature as high as ℃, it expands thermally, but since the upper surface of the orifice plate 2 is not provided with a refractory castable as in the past, only a thin static sand layer 6a is formed. , Fireproof castables are not damaged. Further, as described above, since the refractory castable for restraining the thermal expansion of the orifice plate 2 is not provided, high stress is not generated in the orifice plate 2 and the life of the fluidized bed incinerator is not adversely affected. Furthermore, since the overall height of the furnace body 1 can be reduced by at least the amount corresponding to the thickness of the refractory castable, it can contribute to downsizing of the fluidized bed incinerator, and the maintenance cost of the refractory castable can be reduced. It can contribute to the improvement of the mobility of the fluidized bed incinerator due to the reduction of the time required for maintenance.

Next, a fluidized bed incinerator using high temperature hot air according to a second embodiment of the present invention is shown in FIG.
The present embodiment is different from the above-described embodiment in that the orifice plate 2 is formed in a concave mirror shape with a downward convex shape. Other than this, the structure is exactly the same as that of the fluidized bed incinerator according to the above embodiment.

Therefore, since the static sand layer 6a is formed on the upper surface of the orifice plate 2 and only a part of the air blowing pipe 4a of the air dispersion nozzle 4 is projected on the upper surface of the orifice plate 2, the present embodiment is carried out. The example has the same effect as the above example. However, in this embodiment, since the orifice plate 2 is formed in the shape of a concave concave mirror that is convex downward as described above, the flowability of sand in the sand layer 6 is improved and the plate thickness is the same. However, there is an advantage that the orifice plate 2 has high strength.

A fluidized bed incinerator using high-temperature hot air according to a third embodiment of the present invention will be described with reference to FIG. 3 which is a sectional view showing the main parts. As well understood from the figure, a plurality of ring-shaped cross-sections to be described later centering on an incombustibles outlet (not shown) between the air outlet pipe 4a on the upper surface of the orifice plate 2 and the air outlet pipe 4a. The sand flow prevention dam 5 having a shape is provided concentrically. All of the sand flow prevention dams 5 are inclined toward the outlet for incombustibles, and a heat-resistant and wear-resistant cobalt alloy meat is provided on the end of the sand flow prevention dams 5 facing the inner wall of the fluidized bed incinerator. The raised layer 5a is formed.

Therefore, the presence of the sand flow prevention dam 5 ensures that the static sand layer 6a is formed, while the sand flow prevention dam 5
Is inclined, and the movement of the incombustible in the direction of the incombustible withdrawal outlet can be performed without hindrance, so that this embodiment has the same effect as that of the above-described embodiment 1 or 2. In this case, the sand flow prevention dam 5 is inclined toward the incombustibles outlet side, but the tip of the sand flow prevention dam 5 may be curved toward the incombustibles outlet side, and is not formed into a ring shape. For example, a plurality of flat plates may be arranged in a polygonal shape so as to surround the incombustibles outlet.

As is well understood from FIG. 3, this embodiment is an example in which the sand flow prevention dam 5 is provided on the upper surface of the mortar-shaped orifice plate 2, and this is shown in FIG. The shape is not limited to the shape of the orifice plate 2 because it can be provided to the orifice plate 2 formed in the shape of a concave mirror that is convex toward the side. Further, in the present embodiment, the fluidized bed incinerator in which high temperature air of 650 ° C. from the wind box 7 is blown into the sand layer 6 has been described as an example, but a normal fluidized bed incinerator in which air at a temperature of about 100 ° C. is blown into the sand layer is described. The technical idea according to the present invention can also be applied to a furnace.

[0026]

As described above in detail, according to the fluidized bed incinerator according to claim 1.2 or 3 of the present invention, the conventional structure is provided on the upper surface of the orifice plate provided at the bottom of the furnace body. Since no refractory castables are provided on the slab and only a thin sand layer is formed, cracks may occur in the refractory castables and thermal expansion of the orifice plate may be suppressed by the refractory castables. Since it does not exist, it is possible to reduce the maintenance cost related to the refractory castables of the fluidized bed incinerator, and it is possible to achieve stable operation for a long period of time, which is a great effect.

[Brief description of drawings]

FIG. 1 (a) is a sectional view showing a main part of a fluidized bed incinerator using high temperature hot air according to a first embodiment of the present invention, and FIG. 1 (b) is a part A of FIG. 1 (a). FIG.

FIG. 2 is a sectional view showing a main part of a fluidized bed incinerator using high temperature hot air according to a second embodiment of the present invention.

FIG. 3 is a sectional view showing a main part of a fluidized bed incinerator using high temperature hot air according to a third embodiment of the present invention.

4 (a) is a cross-sectional view of a fluidized bed incinerator according to Conventional Example 1, and FIG. 4 (b) is an enlarged perspective view of a portion C of FIG. 4 (a).

FIG. 5 is a sectional view of a main part of a fluidized bed incinerator according to Conventional Example 2.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Furnace main body 2 ... Orifice plate 3 ... Incombustible material withdrawal port 4 ... Air dispersion nozzle, 4a ... Air blowing pipe, 4b ... Air inflow pipe, 4c ... Cobalt sprayed layer 5 ... Sand flow prevention dam, 5a ... Cobalt alloy overlay Layer 6 ... Sand layer, 6a ... Stationary sand layer 7 ... Wind box 8 ... Refractory material (for furnace inner wall)

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kazuya Izumi 1-3-18 Wakihamacho, Chuo-ku, Kobe-shi, Hyogo Kobe Steel Works, Ltd. Kobe Head Office

Claims (3)

[Claims] Claim: What is claimed is: 1. A sandbox is provided on the bottom of a furnace body to support a sand layer, and the sandbox is convectively flowed from a wind box formed under the bottom of the furnace in the sandbox, and incinerators are burned. An air dispersion device having a plurality of air dispersion nozzles for injecting high temperature air, and a non-combustible material outlet provided in a central portion lower than the outer peripheral portion of the air dispersion device for injecting high temperature air in the horizontal direction. The air blowout pipe of the nozzle is joined for heat resistance.
A fluidized bed incinerator using high-temperature air, characterized in that it has only an orifice plate made of a wear-resistant metal plate. 2. The sand layer is provided on the bottom of the furnace body to support the sand layer, and the sand layer is convectively flowed from a wind box formed below the bottom of the furnace in the sand layer, and the incinerator is burned. An air dispersion device having a plurality of air dispersion nozzles for injecting high temperature air, and a non-combustible material outlet provided in a central portion lower than the outer peripheral portion of the air dispersion device for injecting high temperature air in the horizontal direction. A fluidized bed incinerator using high-temperature air, characterized in that it is composed of only an orifice plate made of a heat-resistant and wear-resistant metal plate, which is formed by joining a nozzle air-blowing pipe and forming a concave concave convex shape downward. 3. The high temperature air according to claim 1, wherein a sand flow prevention dam made of a heat resistant and wear resistant metal plate surrounding the incombustibles outlet is provided on the upper surface of the orifice plate. Fluidized bed incinerator.