JPH09196312A - Fluid bed combustion device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fluid bed combustion device in which energy can be more effectively employed by uniformly and stably burning a combustible material including an incombustible material. SOLUTION: Air diffusing pipes 4 having strong fluidized gas supply holes 5b which form the ascending flow 13 of a fluid medium located in a strong fluidized s area 11 and giving a relatively high fluidized speed to the fluid medium, and air diffusing pipes 4 having weak fluidized gas supply holes 5a which form the descending flow 12 of the fluid medium located in a weak fluidized area 10 and giving a relatively low fluidized speed to the fluid medium are arranged at a prescribed pitch. An incombustible material take out port 3 is provided below the diffusing pipes 4. A combustible material supply port is provided above the weak fluidized area 10 to drop the combustible material into the weal fluidized area 10 and include it in the sedimentation flow 12.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fluidized bed combustion apparatus, and in particular, it uniformly burns a solid substance (combustible substance) containing an incombustible substance such as industrial waste, municipal solid waste, or coal,
Further, the present invention relates to a fluidized bed combustion device capable of stably discharging thermal energy while smoothly discharging incombustibles.

[0002]

2. Description of the Related Art Due to economic development, the amount of general waste is 3
It has increased by ~ 4% and now reaches 50 million tons per year. Moreover, about 82% of this is combustible, and this combustible corresponds to 7.2 million tons in oil equivalent.

Industrial wastes are also increasing, and plastics containing incombustibles, which had been landfilled as unsuitable materials for combustion up to now, are also being used to reduce the burden on landfills.
From now on, it is inevitable to incinerate. The amount of combustible industrial waste such as waste oil and waste plastic is about 17 million tons per year, and the calorific value is 3000 kcal / kg.
Because of the above, effective utilization of these fuels is desired.

However, since these wastes have various properties and shapes, and they are not constant, and indeterminately shaped incombustible substances are mixed, stable combustion and treatment are difficult. Yes, the effective use of energy from general waste and industrial waste is not always sufficiently achieved.

Here, in order to effectively use the energy of general waste and industrial waste, for example, Japanese Patent Laid-Open No. 4-21 is used.
As No. 4110, waste containing incombustibles is burned in a fluidized bed furnace, and at that time, the incombustibles are smoothly discharged to the outside of the fluidized bed furnace for stable combustion, and Japanese Patent Publication No. 5-19.
As No. 044, it is equipped with a descending slope facing the non-combustible exhaust port arranged in the center of the hearth, and the amount of fluidized air per unit area of the hearth is larger near the non-combustible exhaust port and closer to the furnace side wall Fluidized bed furnaces have been proposed, which are designed so that they are supplied so as to be gradually reduced.

[0006]

However, in the above-mentioned conventional example, when there are many incombustibles, the heat loss due to the fluidized medium discharged together with the incombustibles is large, which hinders the effective use of the energy of the combustibles. Therefore, it is required to reduce the amount of fluid medium to be discharged or increase the heat recovery efficiency. Furthermore, in order to reduce costs, development of a simplified fluidized air diffuser is strongly desired.

The present invention has been made in view of the above circumstances, and is a fluidized bed in which a combustible material containing an incombustible component is burned uniformly and stably so that energy can be more effectively used. An object is to provide a combustion device.

[0008]

A fluidized bed combustor of the present invention is a fluidized bed combustor in which combustible substances containing incombustibles are burned, and a large number of fluidized gases are supplied into a fluidized bed furnace. A plurality of air diffuser pipes having a gasification gas supply hole and arranged at a predetermined pitch, and an incombustibles outlet located below the gas diffuser pipe are provided in the bottom of the fluidized bed furnace, and each fluidized gas supply hole is A strong fluidizing gas supply hole that is located in the strong fluidizing zone and gives a relatively large fluidizing velocity to the fluidizing medium to form an upward flow of the fluidizing medium, or is located in the weak fluidizing zone and is relatively small in the fluidizing medium. One of the weak fluidizing gas supply holes that gives a fluidizing velocity to form a settling flow of the fluidized medium, and drops a combustible material to the weak fluidizing region above the weak fluidizing region and swallows the sedimenting flow. It is characterized by arranging a flammable material supply port to be inserted.

According to the present invention having the above-described structure, the fluidized medium that descends in the settling flow inside the fluidized bed furnace, moves horizontally along the upper surface of the diffuser tube, and then rises in the upward flow. A swirl flow is formed. Then, the combustibles that are introduced from the combustibles supply port and swallowed in the sedimentation flow undergo thermal decomposition and also move downward along this sedimentation flow while partially burning,
Combustion is carried out while moving in the horizontal direction, and further violent combustion is carried out due to the oxidizing atmosphere and strong fluidization in the upward flow, so that the unburned components are completely combusted.

In this process, incombustibles contained in combustibles are
Since the specific gravity is larger than that of the flowing medium, it gradually separates and moves downward due to fluidization while moving from the settling flow to the horizontal flow, and is led to the incombustibles discharge port through the diffuser pipe, and some of the flowing medium With this, it is possible to combust combustible substances uniformly while preventing the accumulation of incombustible substances in the fluidized bed furnace.

Further, an inclined wall for diverting the fluidizing gas and the fluid medium rising above the strong fluidizing zone to the central part of the fluidized bed furnace is arranged above the strong fluidizing zone. By providing the inclined wall in this manner, it is possible to block the upward flow of the fluidized medium and allow the fluidized medium to flow horizontally toward the weak fluidization region.

Further, the incombustible material outlet is provided in the substantially center of the substantially cylindrical fluidized bed furnace, and the weak fluidizing gas supply hole and the strong fluidizing gas supply hole are provided around the incombustible material outlet. Arranged in a plurality of concentric circles with the strong fluidizing gas supply holes on the outside, arranged a plurality of air diffusers in a concentric circle centered on the incombustibles outlet, and having a substantially rectangular cross section. The non-combustible matter outlet is provided substantially in the center of the bed furnace, and the weak fluidizing gas supply hole and the strong fluidizing gas supply hole are provided with the strong fluidizing gas supply hole as an outer side with the non-combustible material outlet as the center. It can also be arranged symmetrically.

According to this structure, a settling flow is formed in the center of the fluidized bed furnace, flows outward parallel to the vicinity of the diffuser pipe, and then flows upward along the side wall of the fluidized bed furnace. It is possible to obtain a swirling flow that has formed.

Furthermore, the hearth is composed of an inclined diffuser plate which is inclined downward toward the incombustibles outlet and has a plurality of diffusers therein, and a fluidizing gas is provided below the hearth. An air chamber that is introduced and blows into the fluidized bed furnace from the air diffuser is provided to form a fluidization zone between the hearth and the diffuser pipe, or fluidization between the hearth and the diffuser pipe. A heat recovery device can be placed in the area.

With this structure, it is easy to collect and discharge the incombustibles to and from the incombustibles outlet, and by disposing the heat recovery device in this fluidization region, the incombustibles are discharged together with the incombustibles. The heat can be indirectly recovered from the flowing medium that is used. At the same time, the fluidizing gas in the fluidizing zone directly recovers heat from the fluidizing medium discharged along with the incombustibles, and then becomes a part of the fluidizing gas in the upper fluidized bed as it is. It becomes possible to use the energy of the above more effectively.

Further, a heat recovery chamber having a heat recovery device inside is formed behind the inclined wall, and the upper and lower portions of the inclined wall are connected to the inside of the fluidized bed furnace, and the floor surface of the heat recovery chamber is connected. Is composed of an inclined plate which is inclined inward downward and provided with a plurality of air diffusers therein, and further, a fluidizing gas is introduced below this inclined plate and blown out from the air diffuser into the heat recovery chamber. An air chamber can also be provided.

With this structure, the upward flow formed in the strong fluidization zone is guided from the upper part of the inclined wall to the heat recovery chamber, and by the fluidizing gas blown out from the air diffuser,
It is possible to recover the combustion heat generated in the main combustion chamber in the heat recovery chamber by forming a gentle sedimentation moving bed in the furnace of the heat recovery chamber while gently allowing the high temperature fluidized medium brought into the interior to settle. it can.

[0018]

Embodiments of the present invention will be described below with reference to the drawings. 1 to 3 show a first embodiment of the present invention. FIG. 1 is a longitudinal sectional view, FIG. 2 is a sectional view taken along the line AA of FIG. 1, and FIG. 3 is a sectional view of an air diffusing tube. .

In these figures, a combustible material supply port for introducing a combustible material 2 containing an incombustible material therein is disposed in the center of the upper portion of a substantially cylindrical fluidized bed furnace 1, and the combustible material 2 is disposed in the center of the lower portion. An incombustible material outlet 3 for taking out the incombustible material contained in is disposed.

Inside the fluidized bed furnace 1, a plurality of diffuser pipes 4 which are linearly located at the bottom are arranged in parallel at a predetermined pitch, and the diffuser pipes 4 are arranged on both sides in the horizontal direction. The part is provided with fluidizing gas supply holes 5 at predetermined intervals along the length direction. As shown in FIG. 3, the fluidizing gas supply hole 5 is formed by fitting a nozzle 6 having a predetermined diameter inside the air diffusing pipe 4.

Each diffuser pipe 4 is connected to the fluidizing gas header 7 at its base end, whereby the fluidizing gas introduced into the fluidizing gas header 7 is supplied to the fluidizing gas supply holes 5 respectively.
The air is blown out from the air and is supplied into the fluidized bed furnace 1. The plane formed by the air diffuser 4 is a weak fluidization zone inside the circular boundary line 9 along the inner shape of the furnace wall 8 of the transverse section of the fluidized bed furnace 1 shown by the broken line in FIG. It is divided into 10 and an outer strong fluidization zone 11.

That is, the fluidizing gas supply holes 5 located in the weak fluidizing region 10 and the weak fluidizing gas supplying holes 5a are formed so as to form the weak fluidizing region 10 having a relatively low fluidizing speed. The fluidizing gas supply hole 5 located in the strong fluidizing region 11 is formed as the strong fluidizing gas supply hole 5b so as to form the strong fluidizing region 11 having a relatively high fluidizing speed.

As a result, the weak fluidizing gas supply hole 5a and the strong fluidizing gas supply hole 5 are centered around the center of the fluidized bed furnace 1.
and b are arranged concentrically with the strong fluidizing gas supply hole 5b on the outside.

With this structure, a settling flow 12 of the fluid medium is formed in the weak fluidization region 10 in the center of the furnace, and an upward flow 13 of the fluid medium is formed in the surrounding strong fluidization region 11, and is dispersed. A horizontal flow 14 is formed near the surface of the trachea 4 from the weak fluidization region 10 to the strong fluidization region 11.

On the other hand, the furnace wall above the air diffusing tube 4 of the fluidized bed furnace 1 is formed as an inwardly sloping inclined wall 15, whereby the strong fluidized zone 11 is formed and rises along the furnace wall. The upward flow 13 is converted by the inclined wall 15 into a flow that is directed toward the weak fluidization region 10, so that a continuous swirling flow is formed. Further, the lower part of the air diffusing pipe 4 of the fluidized bed furnace 1 is connected to the incombustibles outlet 3 through an inclined hearth 16 which is inclined inward in an inverted truncated cone shape.

According to this embodiment, the combustible material 2 introduced into the fluidized bed furnace 1 from the combustible material supply port first rides on the settling flow 12 formed in the weak fluidization zone 10 and enters the fluidized bed. It is swallowed, pyrolyzed by the high-temperature fluid medium, and moves downward with partial combustion.

Since the non-combustible matter contained in the combustible material 2 has a larger specific gravity than the fluid medium, most of the non-combustible matter gradually moves downward in the process of transition from the settling flow 12 to the horizontal flow 14, whereby , The incombustible substance concentration of the fluidized medium becomes higher as it goes downward,
After passing through the gap between the air diffusers 4, it goes to the incombustibles outlet 3 along the inclined surface of the hearth 16 and becomes an incombustibles discharge flow, and is discharged from the incombustibles outlet 3 to the outside of the fluidized bed furnace 1. To be done.

On the other hand, after the majority of the incombustibles and a part of the fluidized medium are separated, the remaining fluidized medium becomes a horizontal flow 14 and reaches the strong fluidization zone 11, where it turns to an upward flow 13 and rises. To do. In this upward flow 13, vigorous combustion is performed due to the oxidizing atmosphere and strong fluidization, and the unburned components are also completely burned.

As described above, the swirl flow composed of the settling flow 12, the horizontal flow 14 and the upward flow 13 satisfactorily disperses and mixes the combustibles in the fluidized bed, thereby uniformly and completely combusting the combustibles. It can be carried out.

Here, as shown in FIG. 4, a fluidizing gas supply hole 5 may be directly formed in the tube wall of the air diffusing tube 4. In this case, the drilling position of the fluidizing gas supply hole 5 is a position lower than the horizontal, that is, 0 ≦ when an angle formed with the horizontal axis is θ.
It is preferable that θ <90.

Further, as shown in FIG. 5, a plurality of circular diffusing tubes 4 having different diameters are arranged concentrically at a predetermined pitch, and these diffusing tubes 4 are connected to a fluidizing gas supply source 17. A fluidizing gas supply hole group for introducing the fluidizing gas, that is, a weak fluidizing gas supply hole 5a is arranged inside the boundary line 9 and a strong fluidizing gas supply hole 5b is arranged outside the fluidizing gas supply hole 5a, which are connected to the pipe 18. You can

FIG. 6 shows a second embodiment. The difference of this embodiment from the first embodiment is that it is an inverted truncated cone-shaped inclined diffuser inclined downward toward the incombustibles outlet 3. Air plate 20
And the inclined diffuser plate 20 is provided with a plurality of diffuser ports 21, and below the inclined diffuser plate 20, an air chamber 23 communicating with a fluidizing gas supply source 22 is provided. Therefore, a fluidized region 24 is formed between the inclined diffuser plate 20 and the diffuser pipe 4.

That is, from the fluidizing gas supply source 22 to the air chamber 2
The fluidizing gas introduced into the nozzle 3 is blown out from the diffuser 21 into the fluidizing region 24 between the diffuser 4 and the upper diffuser 4, and the lower portion of the diffuser 4 is fluidized to discharge the incombustibles. In addition to making it easier, the fluidized gas, which has recovered heat from the fluidized medium discharged together with the incombustibles, is used as it is as a part of the fluidized gas in the upper fluidized bed, so that it is possible to efficiently recover heat and achieve high efficiency. Burning can take place.

FIG. 7 shows a third embodiment. The difference of this embodiment from the second embodiment is that a fluidization region 24 between the inclined diffuser plate 20 and the diffuser pipe 4 is provided below. The heat recovery device 33 is formed by connecting the headers 31 and 32 to both ends of the heat transfer tube 30.

As described above, the heat recovery device 3 is provided in the fluidization zone 24.
By disposing No. 3, heat is indirectly recovered from the fluidized medium discharged together with the incombustibles, and the fluidized gas obtained by directly recovering the heat from the fluidized medium is directly used as a part of the fluidized gas in the upper fluidized bed. Can be used as a fuel cell to perform more efficient combustion.

FIG. 8 shows a fourth embodiment. The difference of this embodiment from the third embodiment is as follows.

That is, above the strong fluidizing region 11 having a relatively high fluidizing speed, an inclination that blocks the upward flow of the fluidizing medium and flows the fluidizing medium toward the weak fluidizing region 10 having a low fluidizing velocity. Although the wall 15 ′ is provided, the heat recovery chamber 40 is formed behind the inclined wall 15 ′, and inside the heat recovery chamber 40, the headers 42, 4 are provided at both ends of the heat transfer tube 41.
A heat recovery device 44 configured by connecting 3 is arranged.

Further, the floor surface of the heat recovery chamber 40 is composed of an inclined plate 46 which inclines downward inward and has a large number of air diffusers 45. An air chamber 48 that communicates with the gasification supply source 47 and blows the fluidized gas into the heat recovery chamber 40 from the diffuser port 45 is provided. Here, the inclined wall 15 'is opened to the main combustion chamber at the upper end thereof, and is also connected to the main combustion chamber via the communication port 49 at the lower portion.

As a result, the upward flow 13 formed in the strong fluidization region 11 is weakened by the inclined wall 15 '.
However, at the same time, a part thereof is separated into the reversal flow 50, and the reversal flow 50 flows into the heat recovery chamber 40.

Then, a sedimentation moving layer is formed in the heat recovery chamber 40, and this sedimentation moving layer is gently fluidized by the fluidizing gas blown out from the diffusion port 45 provided in the inclined plate 46. Since the fluidized medium is formed while being converted, the high temperature fluid medium brought in by the reversal flow 50 is gradually settled, is heat-collected and cooled by the heat transfer tube 41, and is refluxed from the communication port 49 to the main combustion chamber. Thereby, the heat of combustion generated in the main combustion chamber can be recovered in the heat recovery chamber 40.

Each of the above-mentioned embodiments shows an example applied to a cylindrical fluidization furnace, but the inner shape 8 having a substantially rectangular cross section is used.
FIG. 9 shows an example of an optimal air diffuser when it is applied to a fluidizing furnace having a.

That is, the weak fluidizing region 10a and the strong fluidizing region 11a are divided by a boundary line 9a (shown by a broken line in the figure) having a rectangular frame shape and extending over substantially the entire length in the length direction of the air diffusing tube 4,
The diffuser pipe 4 located in the weak fluidization region 10a is provided with a weak fluidizing gas supply hole 5a, and the diffuser pipe 4 located in the strong fluidization region 11a is provided with a strong fluidizing gas supply hole 5b. .

In this case, two kinds of air diffusing pipes 4 are prepared: an air diffusing pipe 4 having only weak fluidizing gas supply holes 5a and an air diffusing pipe 4 having only strong fluidizing gas supply holes 5b. It can be easily manufactured.

[0044]

Since the present invention has the above configuration,
The injected combustible material undergoes thermal decomposition in the sedimentation flow, moves downward while performing partial combustion, and is further combusted while moving in the horizontal direction. In the process, the incombustible material contained in the combustible material is , Gradually move downward, pass through the diffuser pipe, and are guided to the incombustibles discharge port. On the other hand, the fluid medium containing the combustibles remaining after the separation of the majority of the incombustibles and a part of the fluid medium undergoes intense combustion due to the oxidizing atmosphere and strong fluidization in the upward flow of the strong fluidization region. As a result, the unburned matter is completely burned. As a result, it is possible to perform uniform and complete combustion while easily separating and discharging incombustibles.

Moreover, by forming a fluidization zone between the hearth and the diffuser, and disposing a heat recovery device in this fluidization zone,
Indirect heat recovery is performed from the fluidized medium discharged along with the incombustibles, and the fluidized gas in this fluidized zone is used as part of the fluidized gas in the upper fluidized bed to increase the energy of combustibles. It can be collected efficiently.

Further, a heat recovery chamber is formed behind the inclined wall,
While arranging the heat recovery device inside this heat recovery chamber,
Equipped with an air diffuser, and by providing a communication port with the main combustion chamber in the lower part of the inclined wall, a reverse flow that flows into the heat recovery chamber from the upward flow formed in the strong fluidization zone is obtained, and heat recovery The fluidized gas blown out from the diffuser of the hearth of the chamber forms a gentle settling and moving bed, and after heat-collecting and cooling by the heat recovery device, it can be returned to the main combustion chamber from the communication port. The heat of combustion generated in the combustion chamber can be recovered in the heat recovery chamber.

That is, by configuring in this way,
It is possible to simultaneously and effectively perform separation and discharge of incombustibles from combustibles including incombustibles in a fluidized bed, uniform combustion, and highly efficient energy recovery.

[Brief description of drawings]

FIG. 1 is a longitudinal sectional view showing a first embodiment of the present invention.

2 is a sectional view taken along line AA of FIG.

FIG. 3 is a sectional view of the air diffuser.

FIG. 4 is a view corresponding to FIG. 3 showing another example of the air diffuser.

FIG. 5 is a view corresponding to FIG. 2 showing another example of the arrangement of the air diffusing tubes.

FIG. 6 is a longitudinal sectional view showing a second embodiment of the present invention.

FIG. 7 is a longitudinal sectional view showing a third embodiment of the present invention.

FIG. 8 is a longitudinal sectional view showing a fourth embodiment of the present invention.

FIG. 9 is a view corresponding to FIG. 2 showing still another example of the arrangement of the air diffusing tubes.

[Explanation of symbols]

 1 fluidized bed furnace 2 combustibles 3 incombustibles outlet 4 diffuser 5 fluidizing gas supply hole 5a weak fluidizing gas supply hole 5b strong fluidizing gas supply hole 10 weak fluidizing area 11 strong fluidizing area 12 sedimentation flow 13 top Counterflow 14 Horizontal flow 15,15 'Inclined wall 20 Inclined diffuser (hearth) 21,45 Diffuser 23,48 Air chamber 24 Fluidization area 33,44 Heat recovery device 40 Heat recovery chamber 46 Inclined plate

 ──────────────────────────────────────────────────の Continued on the front page (72) Inventor Takahiro Oshita 11-1 Haneda Asahimachi, Ota-ku, Tokyo Inside Ebara Corporation

Claims (8)

[Claims] 1. A fluidized bed combustion device for burning a combustible material containing incombustibles, comprising a plurality of fluidized gas supply holes for supplying fluidized gas into a fluidized bed furnace and arranged at a predetermined pitch. And a non-combustible material outlet located below the air diffuser are provided in the bottom of the fluidized bed furnace, and each fluidizing gas supply hole is located in the strong fluidizing zone and is relatively large in the fluidizing medium. A fluidizing velocity is applied to form a strong fluidizing gas supply hole that forms an upward flow of the fluidizing medium, or a weak fluidizing zone is provided to impart a relatively low fluidizing velocity to the fluidizing medium to settle the settling flow of the fluidizing medium. One of the weak fluidizing gas supply holes to be formed, and a flammable material supply port for dropping the combustible material into the weak fluidizing area and swallowing it into the sedimentation flow is arranged above the weak fluidizing area. And fluidized bed combustion equipment. 2. An inclined wall for arranging the fluidizing gas and the fluid medium rising above the strong fluidization zone toward the central part of the fluidized bed furnace is arranged above the strong fluidization zone. The fluidized bed combustion apparatus according to 1. 3. The incombustibles outlet is provided at substantially the center of a substantially cylindrical fluidized bed furnace, and the weak fluidizing gas supply hole and the strong fluidizing gas supply hole are provided around the incombustibles outlet. The fluidized bed combustion apparatus according to claim 1 or 2, wherein the strong fluidizing gas supply holes are arranged in a plurality of rows in a concentric circle shape on the outside. 4. The fluidized bed combustion apparatus according to claim 3, wherein the plurality of air diffusers are arranged concentrically around the incombustibles outlet. 5. The incombustibles outlet is provided substantially in the center of a fluidized bed furnace having a substantially rectangular cross section, and the weak fluidizing gas supply hole and the strong fluidizing gas supply hole are centered around the incombustibles outlet. 3. The fluidized bed combustion apparatus according to claim 1 or 2, wherein and are arranged symmetrically in a plurality of rows with the strong fluidizing gas supply holes on the outside. 6. A hearth is composed of an inclined air diffuser plate that is inclined downward toward the incombustibles outlet below the air diffuser and is provided with a plurality of air diffusers inside the hearth. A fluidized region is formed between the hearth and the diffuser pipe by providing an air chamber in which a fluidized gas is introduced and blown into the fluidized bed furnace from the diffuser port. The fluidized bed combustion apparatus according to any one of 1 to 5. 7. The fluidized bed combustor according to claim 6, wherein a heat recovery device is arranged in the fluidized region between the hearth and the diffuser pipe. 8. A heat recovery chamber having a heat recovery device inside is formed behind the inclined wall, and upper and lower parts of the inclined wall are connected to the inside of the furnace so that the floor surface of the heat recovery chamber is inside. An air chamber that is inclined downward toward one side and is provided with a plurality of diffuser ports inside, and further introduces a fluidizing gas below the inclined plate and blows out from the diffuser port into the heat recovery chamber. The fluidized bed combustion apparatus according to claim 2, further comprising: