JP2003336819A - Air diffuser for fluidized bed incinerator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To supply air to a fluidized bed and to absorb heat from the fluidized bed. <P>SOLUTION: An air diffuser duct 16 having a function of air supply to the fluidized bed 6 and a function of heat absorption from the fluidized bed 6 is penetratingly arranged at a lower position in a furnace 1 adapted to form the fluidized bed 6. The air diffuser duct 16 is constructed by forming a water tube wall in a duct shape, which comprises a number of water tubes 13 and fins 14 connecting the respective water tubes 13 with one another, and by installing a number of air diffuser nozzles 15 on the fins 14. Primary air introduced into the air diffuser duct 16 blows off from the respective air diffuser nozzles 15 toward the fluidized bed 6 to fluidize the fluidized bed 6. Boiler feed water is passed through the respective water tube 13 to absorb heat of the fluidized bed 6 for heat recovery. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air diffuser for a fluidized bed incinerator used to incinerate waste such as municipal solid waste.

[0002]

2. Description of the Related Art A fluidized bed type incinerator for incinerating wastes such as municipal waste is a primary combustion in a lower position in a vertically extending furnace 1 as shown in FIG. 3 (a) and (b). A chamber 2 is provided, and a secondary combustion chamber 3 is provided above the chamber 2,
Inside the primary combustion chamber 2, an air diffuser device 5 of the air diffuser type connected to the primary air pipe 4 is arranged at the bottom, and after being filled with sand as a fluid medium, it is jetted from the air diffuser 5. A fluidized bed 6 is formed by primary air, while the secondary combustion chamber 3 constitutes a wall portion by a large number of water pipes 8 connected to a steam drum 7, and a secondary air pipe 9 is formed on the wall portion. Was introduced into the fluidized bed 6 to burn the waste in the primary combustion chamber 2 with the primary air, and further in the secondary combustion chamber 3 with the secondary air. Combustion heat is recovered by exchanging heat in the water pipe 8 to obtain steam. The incombustibles contained in the waste are extracted together with the sand from the lower part of the furnace 1 and separated, and the sand after the separation of the incombustibles is returned to the furnace 1.

The air diffuser 5 used to fluidize the fluidized bed 6 has an air diffuser pipe header 10 communicating with a primary air pipe 4 as shown in an enlarged view in FIG.
A plurality of thick diffusing tubes 11 are branched and connected, and a large number of small diffusing holes 12 are bored in the lateral direction on the side surface of each diffusing tube 11 at required intervals in the longitudinal direction. ,
The primary air supplied from the diffuser pipe header 10 into each diffuser pipe 11 is blown into the sand of the fluidized bed 6 through each diffuser hole 12 to fluidize the sand above the diffuser pipe 11. The air diffuser 11 is made of stainless steel in order to suppress corrosion due to high temperature,
Further, when the operation is stopped, even if the sand (dry sand) of the fluidized bed 6 enters the diffuser holes 12, the angle of repose is formed and the pipe wall thickness is set so that the sand does not enter the inside of the pipe.

In the fluidized bed incinerator having the air diffuser 5 as described above, when waste is put on the fluidized bed 6,
First, the waste is pyrolyzed and burned in the fluidized bed 6 and the primary combustion chamber 2. The combustion of this waste causes the temperature of the fluidized bed 6 to rise. When the temperature becomes excessive, the reaction rate becomes faster, the thermal decomposition rate also becomes faster, and the air supplied for combustion may be inadequate with respect to the required air amount that changes due to fluctuations in dust quality and amount, This will cause incomplete combustion. For this reason, it is desirable to operate at a low combustion temperature, but since recent wastes have a high calorie content, when they are burned, the heat retained in the fluidized bed 6 becomes excessive and the fluidized bed temperature rises excessively. Therefore, it is necessary to remove heat in order to suppress abnormal combustion, and conventionally, water is sprayed toward the fluidized bed 6, or a fluidizing section for absorbing heat is provided to control the temperature of the fluidized bed 6. I have to.

[0005]

However, in the system in which the temperature of the fluidized bed 6 is controlled by spraying water onto the fluidized bed 6, a loss of heat of recovery occurs due to the latent heat of vaporization of water.
There is a problem that the evaporation amount of the boiler decreases.

Further, in the system in which a fluidizing section for heat absorption is separately provided in the fluidized bed 6 to control the temperature, the air diffuser 11 of the air diffuser 5 is used.
In addition to this, a heat transfer tube for heat absorption is located inside the fluidized bed 6, which may cause corrosion problems of the heat transfer tube in the fluidizing section for heat absorption and cause non-combustible materials to be easily caught and to accumulate non-combustible materials. However, there is a problem that fluidity may eventually be caused.

Therefore, the present invention is intended to provide an air diffuser capable of absorbing heat from the fluidized bed in addition to the function of supplying air to the fluidized bed in a fluidized bed type incinerator. is there.

[0008]

SUMMARY OF THE INVENTION In order to solve the above problems, the present invention provides a water pipe wall formed by connecting a plurality of water pipes with fins into a tubular shape extending in the direction of each water pipe. A plurality of diffuser nozzles are attached to form an diffuser pipe, a plurality of diffuser pipes made of the water pipe wall are arranged at the bottom of the furnace, and boiler water is circulated in the water pipes of the diffuser pipes, The primary air introduced into each air diffusing tube is jetted from each air diffusing nozzle to fluidize the fluidized medium.

Since the boiler water flows through the water pipe, the diffuser pipe can absorb the heat of the fluidized bed, which can prevent the temperature of the fluidized bed from rising excessively and efficiently recover the heat.

Further, since the air diffuser consisting of the wall of the water pipe has an elliptical shape that is elongated in the vertical direction, the surface area of the air diffuser can be increased, so that a larger heat absorbing action and heat recovery effect can be exhibited. be able to.

Further, a number of air diffuser nozzles are attached to each fin of the water pipe wall formed by connecting a plurality of water pipes by fins to form an air diffuser plate, and the air diffuser plate composed of the water pipe walls is Arranged as the furnace bottom plate of the furnace, and provided with a wind box at the bottom of the air diffuser plate, while allowing the boiler water to circulate in the water pipe of the air diffuser plate, the primary air introduced into the air box is By adopting a structure in which the fluidized medium is fluidized by being jetted from each air diffuser nozzle, heat can be absorbed from the fluidized bed by the air diffuser plate, and excessive rise of the fluidized bed temperature can be prevented.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.

FIGS. 1 (a), (b) and (c) show an embodiment of the present invention. In a fluidized bed type incinerator having the same structure as shown in FIG. 3 (a) (b), At the bottom of the furnace 1, an air diffuser type air diffuser 5A having an air supply function and a heat absorption (heat removal) function is arranged.

In the air diffuser 5A, a water pipe wall formed by connecting a large number of horizontally arranged water pipes 13 made of steel pipes with fins 14 made of steel strip is an elliptical shape (elliptical shape) extending parallel to each water pipe 13. , And a plurality of air diffuser nozzles 15 made of steel pipes are attached to the required fins 14 located on the sides so as to face each other in the lateral direction to form the air diffuser pipe 16, and A plurality of the air diffusers 16 are arranged in parallel at the bottom of the furnace 1 at a required interval in the horizontal direction so that the air diffuser nozzles 15 are horizontally oriented in the fluidized bed 6, and both ends thereof are arranged. The air diffuser 16 is penetrated to the outside of the furnace to be protruded,
Is closed with a closing plate 17 and the other end of each air diffusing pipe 16 is closed with a primary air pipe connecting flange 17a, the primary air pipe 4 is connected, and the air is supplied into the air diffusing pipe 16 through the primary air pipe 4. By ejecting the primary air from each air diffusion nozzle 15, the fluidized bed 6 above the air diffusion pipe 16 can be fluidized.

Further, the diffuser pipe 16 protruding from the bottom of the furnace 1 has an elliptical ring shape on the outer circumference at one end and the outer circumference at the other end.
Boiler water manifolds 18 and 19 are arranged, both ends of each water pipe 13 are connected to and communicate with both of these manifolds 18 and 19, and one manifold 18 is connected to a downfall pipe 20 led from the steam drum 7. At the same time, the other manifold 19 is connected to, for example, an ascending pipe 21 to the steam drum, and the boiler water sent from the steam drum 7 is supplied into the manifold 18 through the downcomer pipe 20,
When the branched boiler water is merged into the manifold 19 through the water pipes 13, the boiler water absorbs heat of the fluidized bed 6 via the water pipes 13 and the fins 14.

The diffusing nozzle 15 is made of a small diameter pipe so that even if the sand of the fluidized bed 6 enters the pipe when the operation is stopped, the sand does not enter the diffusing pipe 16 due to the angle of repose. It is set to the length. The other structure is the same as that shown in FIG. 3A, and the same portions are denoted by the same reference numerals.

When burning the waste in the furnace 1, when the primary air is supplied through the primary air pipe 4 into the diffuser pipe 16 formed of the water pipe wall, the diffuser nozzles 15 provided in the diffuser pipe 16 are provided. When the primary air is jetted into the fluidized bed 6, the fluidized bed 6 is fluidized. On the other hand, when the boiler water sent from the steam drum 7 is introduced into the manifold 18 through the downfall pipe 20, the boiler water is discharged. Absorbs heat to be mixed with brackish water while being joined to the manifold 19 through the water pipes 13, and is sent to the steam drum 7 through the rising pipe 21 in the same manner as brackish water from other parts, and after steam separation, the steam is discharged to the outside of the boiler. To do. Now, when the waste material is put on the fluidized bed 6, the waste material is supplied to each air diffusion nozzle 1 of the air diffusion pipe 16.
After being primary burned by the primary air jetted from 5, the secondary air supplied through the secondary air pipe 9 is further burned. At this time, since the recent waste has a high calorie, combustion of the waste causes fluidized bed 6
However, since the boiler water circulates in each water pipe 13 of the air diffusing pipe 16, the cold heat of the boiler water causes the fluidized bed 6 to flow on the surface of the air diffusing pipe 16 including the water pipe 13 and the fins 14. Therefore, the temperature in the fluidized bed 6 does not rise excessively, and stable combustion can be performed. Also, there is no loss of heat recovered due to latent heat of vaporization of water as in the case of spraying water. Moreover, the air diffuser 16
Since it has an elliptical shape and a large heat transfer area is obtained, heat can be efficiently recovered.
Further, since the air diffuser 16 has an oval tubular shape, the incombustibles are not caught and deposited, and the fluidized bed 6 does not flow poorly.

In the above, the amount of heat absorption required in the fluidized bed 6 is known in advance depending on the size of the furnace 1, etc. Therefore, the temperature of the fluidized bed 6 can be kept constant by selecting the cross-sectional area of the diffuser pipe 16. Can be controlled. Therefore, the air diffuser 1
As the water pipes 13 and the fins 14 that form part 6, ordinary steel pipes or steel strips can be used, and since it is not necessary to use stainless steel or the like for heat resistance, they can be manufactured at low cost. Also, by making the water pipe 13 of steel pipe, it is possible to replace and replace (extract pipe) only the worn part, and the maintenance cost can be reduced.

Next, FIGS. 2 (a) and (b) show another embodiment of the present invention. FIG. 1 (a) (b) (c) (d)
In the fluidized bed type incinerator having the same configuration as that shown in FIG. 1, instead of providing the diffuser device 5A of the diffuser pipe system at the bottom of the furnace 1, the diffuser device 5B of the diffuser plate system is adopted,
The bottom plate of the furnace 1 has a boiler steel tube water tube wall structure with fins. That is, a water pipe wall composed of a large number of water pipes 13 made of steel pipes arranged in parallel and fins 14 made of steel strip that connect the water pipes 13 to each other is formed so that the longitudinal direction of the water pipes 13 is along the inclination of the furnace bottom. And each of the fins 14 has an air diffusion nozzle 22 at a required pitch in the longitudinal direction.
Is installed upwards to form a diffuser plate 23, and the diffuser plate 23 is installed as a bottom plate of the furnace 1, and further the diffuser plate 2 is installed.
On the lower side of 3, the wind box 2 partitioned into, for example, three compartments
4 are provided, and the primary air pipes 4 are provided in the respective compartments of the wind box 24.
Are connected to each other, and the primary air supplied into the wind box 24 through the primary air pipe 4 is ejected from each air diffusion nozzle 22 so that the fluidized bed 6 can be fluidized. Further, the upper ends of the water pipes 13 of the air diffuser plate 23 are connected to the boiler water manifold 19a so as to communicate with each other, and the lower ends of the water pipes 13 are connected to the boiler water manifold 18a so as to communicate with each other, and the manifold 18a is connected to the steam drum. 7 is connected to the downcomer pipe 20, and the steam drum 7 is connected to the manifold 19a.
Boiler water sent from the steam drum 7 is supplied into the manifold 18a through the downcomer pipe 20 and further joined into the manifold 19a through the respective water pipes 13a. The heat of the fluidized bed 6 is absorbed by the boiler water through the water pipes 13 and the fins 14.

As shown in the enlarged view of FIG. 2C, the air diffuser nozzle 22 is made of a pipe whose top is closed, and a plurality of nozzles are horizontally provided on the outer periphery of the upper end protruding above the fin 14. The holes 22a are provided so that the primary air sent from the wind box 24 is ejected horizontally from the nozzle holes 22a so that sand as a fluid medium does not enter the nozzle holes 22a. is there.

Reference numeral 25 denotes a sand removing device. The other structure is the same as that shown in FIG. 1A, and the same portions are denoted by the same reference numerals.

When the air diffuser 5B configured as shown in FIGS. 2A, 2B and 2C is adopted, the primary air supplied into the wind box 24 through the primary air pipe 4 is provided on the fins 14. The fluidized bed 6 can be fluidized by being ejected from the nozzle holes 22a of the respective air diffuser nozzles 22 that are burned, and the waste that is put on the fluidized bed 6 can be burned. At this time, the boiler water is circulated in each water pipe 13, so that the diffuser plate 23 as the furnace bottom plate
Since heat is absorbed from the fluidized bed 6 by the entire surface of
The same operational effects as in the case of the embodiment of FIGS. 1A, 1B, and 1C can be obtained.

In the embodiment shown in FIGS. 1A, 1B and 1C, the diffusing tube 16 has an oval cross section, but it may have a perfect circular shape. , Fig. 2
In the embodiment shown in (a), (b) and (c), the diffuser plate 23
Although the case of tilting the furnace toward one side of the lower end of the furnace 1 is shown, the arrangement shape may be selected according to the model of the furnace 1, such as tilting toward both sides of the lower end of the furnace 1. Needless to say, various changes can be made without departing from the scope of the present invention.

[0024]

As described above, according to the air diffuser of the fluidized bed type incinerator of the present invention, the following excellent effects are exhibited. (1) A water pipe wall formed by connecting a plurality of water pipes with fins is formed into a tubular shape extending in the direction of each water pipe, and a plurality of air diffusion nozzles are attached to required fins to form an air diffusion pipe, and the water pipe wall A plurality of air diffusers consisting of the furnace bottom are provided, and the boiler water is circulated in the water tubes of each air diffuser, and the primary air introduced into each air diffuser is jetted from each air diffuser nozzle. Since it is configured to fluidize the fluid medium,
It is possible to absorb the heat of the fluidized bed with the entire diffuser tube by using the boiler water that is circulated in the heat transfer tube, and thus it is possible to prevent the temperature inside the fluidized bed from rising excessively and to perform stable combustion. At the same time, heat can be efficiently recovered without loss due to water spraying, and since the fluidized bed can be controlled to a constant temperature, it is not necessary to use a high-grade material for heat resistance, and thus it can be manufactured at low cost. In addition, it is possible to replace only the worn portion, which is advantageous in terms of maintenance. (2) By making the air diffuser consisting of the water pipe wall an elliptical shape that becomes longer in the vertical direction, the surface area of the entire air diffuser can be increased, resulting in a larger endothermic action and a more efficient heat recovery effect. can get. (3) A plurality of diffuser nozzles are attached to each fin of the water pipe wall formed by connecting a plurality of water pipes with fins to form a diffuser plate, and the diffuser plate formed of the water pipe walls is used for the furnace. It is arranged as a bottom plate of the furnace, and a wind box is provided below the diffuser plate so that the boiler water is circulated in the water pipe of the diffuser plate, and the primary air introduced into the wind box is dispersed. Since the fluidized medium can be fluidized by being ejected from the air nozzle, the heat of the fluidized bed can be absorbed by the entire bottom plate of the furnace by the diffuser plate, so the fluidized bed temperature is prevented from rising excessively. As a result, heat can be recovered efficiently.

[Brief description of drawings]

FIG. 1 shows an embodiment of an air diffuser for a fluidized bed incinerator according to the present invention, in which (a) is a schematic diagram of the whole and (b) is an enlarged arrow view in the AA direction of (a). Figure, (c) is B- of (a)
FIG. 7 is an enlarged arrow view in the B direction, and (d) is an enlarged perspective view of a C portion in (c).

FIG. 2 shows another embodiment of the present invention, in which (a)
Is a schematic diagram of the whole, (b) is an enlarged perspective view of the D part of (a),
(C) is an enlarged cross-sectional view of the E portion of (B).

FIG. 3 shows an example of a conventional fluidized bed incinerator,
(A) is an overall schematic view, and (B) is a partially enlarged perspective view of an air diffusing device of an air diffusing tube type.

[Explanation of symbols]

1 furnace 6 fluidized bed 13 water pipe 14 fins 15 Aeration nozzle 16 Air diffuser 22 Aeration nozzle 23 Air diffuser 24 wind box

Claims (3)

[Claims] 1. A water pipe wall formed by connecting a plurality of water pipes with fins is formed into a tubular shape extending in the direction of each water pipe, and a plurality of air diffusion nozzles are attached to required fins to form an air diffusion pipe. A plurality of diffuser tubes consisting of tube walls are installed at the bottom of the furnace to allow boiler water to flow through the water tubes of each diffuser tube, and the primary air introduced into each diffuser tube is ejected from each diffuser nozzle. An air diffuser for a fluidized bed incinerator, characterized in that it is configured to fluidize the fluidized medium. 2. An air diffusing device for a fluidized bed incinerator according to claim 1, wherein the air diffusing pipe formed of the water pipe wall has an oval shape that is elongated in the vertical direction. 3. A diffuser plate is constructed by attaching a number of diffuser nozzles to each fin of a water pipe wall formed by connecting a plurality of water pipes with fins, and the diffuser plate comprising the water pipe wall is Arranged as the furnace bottom plate of the furnace, and provided with a wind box at the bottom of the air diffuser plate, while allowing the boiler water to circulate in the water pipe of the air diffuser plate, the primary air introduced into the air box is An air diffuser for a fluidized bed incinerator, which is configured to be jetted from each air diffuser nozzle to fluidize a fluidized medium.