JP2930232B2 - Fluidized bed heat recovery apparatus and operation method thereof - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fluidized bed heat recovery apparatus for incinerating industrial waste, municipal solid waste, coal and the like by forming a fluidized bed composed of sand particles and the like, and recovering heat generated thereby, and operation thereof. It is about the method.

[0002]

2. Description of the Related Art Conventionally, a fluidized bed heat recovery apparatus for forming a fluidized bed composed of sand particles on an air dispersion plate has been often used as an apparatus for recovering heat generated by incineration of industrial wastes.
This apparatus has the advantages that the mixing of the particles in the fluidized bed is extremely good, the temperature in the bed can be kept uniform, and that the particle layer has a large heat retention capability, so that it can be easily restarted. I have.

As such an apparatus, for example, Japanese Patent Application Laid-Open
Japanese Patent Publication No. 187001 discloses a configuration as shown in FIG.

In FIG. 1, a mountain-shaped air distribution plate 92 is provided at the bottom of a furnace 90, and the air discharged from a blower 91, that is, a fluidizing gas is blown upward from the air distribution plate 92, whereby sand is formed. A fluidized bed of particles is formed. Specifically, the gas injection speed at the left and right wings of the dispersion plate 92 is set to be higher than that at the center, and
Above the air dispersion plate 92, a reflective partition 93 having a shape facing the jetting direction of the fluidizing gas is provided.
For this reason, the sand particles form a fluidized bed that is vigorously blown up by the left and right wings, is reflected by the reflection partition 93, and sinks at the center.

For such a fluidized bed, an upper inlet 8 is provided.
When an object to be treated such as municipal solid waste is introduced into the central main combustion chamber 96 from 9, the object to be treated is burned while flowing together with the sand particles in the fluidized bed, and the incombustible material is discharged into the incombustible material outlet 98.
And carried out of the apparatus by the screw conveyor 99. In addition, some of the sand particles enter the heat recovery chamber 94 outside the reflection partition 93 and settle in the heat recovery chamber 94. A heat transfer tube 95 is provided in the heat recovery chamber 94, and the heat of the sand particles entering the heat recovery chamber 94 is recovered by the heat transfer tube 95.

[0006]

In the above apparatus, the heat generated by the combustion of the processing object is transmitted to the heat transfer tube 95 via the sand particles flowing in the furnace. In other words,
Of the heat generated by incineration of the object, only the heat generated in the fluidized bed can be recovered by the heat transfer tube 95.

However, the ratio of the amount of heat generated in the fluidized bed to the total amount of heat (hereinafter referred to as the combustion rate) is at most a little over 50%, and the remainder is due to combustion on a free board above the fluidized bed. Escaped to the atmosphere. In particular, as the object to be treated, when waste such as plastics, which is easily gasified and burned, or when waste having a low calorific value per unit weight is administered, the burning rate is extremely low. Accordingly, a great loss occurs in heat recovery.

In view of the above circumstances, it is an object of the present invention to provide a fluidized bed heat recovery apparatus capable of improving heat recovery efficiency from a fluidized bed with a simple configuration and a method of operating the same.

[0009]

As a means for solving the above-mentioned problems, the present invention provides a method for receiving a fluidizing gas injected from an air diffuser on an air diffuser provided at the bottom of the apparatus body. In the fluidized bed heat recovery apparatus, a fluidized bed composed of flowing fluidized particles is formed, and a heat recovery means for recovering heat generated by incineration of an object to be processed in the fluidized bed is provided in the fluidized bed. An oxygen-rich gas having an oxygen gas concentration higher than the oxygen gas concentration in air is injected as a fluidizing gas injected from at least a part of the gas device (claim 1).

Further, according to the present invention, a fluidized bed composed of fluidized particles flowing upon receiving a fluidizing gas injected from the diffuser is formed on the diffuser provided at the bottom of the apparatus body,
A heat recovery unit is provided in the fluidized bed for recovering heat generated by incineration of an object to be processed in the fluidized bed, and the fluidized bed is provided with a heat recovery unit provided with the heat recovery unit and a processing object. In a fluidized bed heat recovery device provided with a partition member for partitioning the main combustion section into which the oxygen gas is administered, at least a part of the main combustion section has an oxygen gas concentration as the fluidizing gas of oxygen in air. An oxygen-rich gas higher than the gas concentration is injected, and a gas having an oxygen concentration equal to or lower than the oxygen gas concentration in the air is injected as the fluidizing gas to the heat recovery unit.

In this method, a gas obtained by adding oxygen gas to air as the fluidizing gas is injected into at least a part of the main combustion section, and the fluidizing gas is injected into the heat recovery section as the fluidizing gas. Injecting air as it is is particularly preferable (claim 3).

The oxygen gas concentration of the oxygen-rich gas is 3
More preferably, it is less than 0% (claim 4).

Further, according to the present invention, a fluidized bed composed of fluidized particles flowing upon receiving a fluidizing gas injected from the diffuser is formed on the diffuser provided at the bottom of the apparatus body,
A heat recovery unit is provided in the fluidized bed for recovering heat generated by incineration of an object to be processed in the fluidized bed, and the fluidized bed is provided with a heat recovery unit provided with the heat recovery unit and a processing object. In the fluidized bed heat recovery device provided with a partition member for partitioning the main combustion portion into which the oxygen gas concentration is air as the fluidizing gas from the diffuser device to at least a part of the main combustion portion. First injecting means for injecting an oxygen-enriched gas higher than the oxygen gas concentration in the air, and wherein the oxygen concentration is equal to or less than the oxygen gas concentration in the air as the fluidizing gas from the air diffuser to the heat recovery unit. And second injection means for injecting gas.

In the apparatus, as the first injection means, an air supply means for supplying air to a gas injection section of the air diffuser, and oxygen gas is supplied to the air before the air is injected from the gas injection section. It is particularly preferable that the second injection means include an air supply means for directly supplying air to the gas injection section of the air diffuser (claim 6).

The oxygen-rich gas has an oxygen gas concentration of 3%.
It is more preferable to configure the first injection means so as to be less than 0% (claim 7).

According to the first aspect of the present invention, the fluidized gas injected from at least a part of the air diffuser into the fluidized bed is enriched with an oxygen gas concentration higher than the oxygen gas concentration in air. Since oxygen gas is used, the combustion of the processing object in the fluidized bed is promoted as compared with the conventional case where air is directly injected as fluidizing gas. Thereby, the combustion rate in the fluidized bed is increased, and the efficiency of heat recovery from the fluidized bed by the heat recovery means is increased.

Here, when the fluidized bed is divided into a heat recovery section and a main combustion section by a partition member, the oxygen gas concentration of the fluidized gas injected into the main combustion section is increased to increase the fluidized bed. The combustion rate inside can be increased.

More specifically, in the method and the apparatus according to the third and sixth aspects, a gas obtained by adding oxygen gas to air as the fluidizing gas is injected into at least a part of the main combustion section. By directly injecting air as the fluidizing gas into the heat recovery unit, the heat recovery efficiency can be increased by inexpensive means that makes full use of the air.

If the oxygen concentration of the oxygen-enriched gas is too high (specifically, 30% or more), combustion in the fluidized bed is excessively promoted, and there is a possibility that the inner wall and the partition member of the apparatus body may be damaged. There is. Therefore, by setting the oxygen gas concentration of the oxygen-rich gas to be less than 30%, the heat recovery efficiency can be increased without damaging the apparatus.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described with reference to FIGS.

The fluidized bed heat recovery device shown in FIG.
An incinerator 10 surrounded by 1 is provided. A fluidized bed 12 made of sand or the like is formed at the bottom of the incinerator 10. An incineration material inlet 16 is formed in the middle part of the incinerator, and an incineration material supply device 18 is connected to the incineration material inlet 16. A secondary air blower 20 is also connected to an appropriate height position of the middle part of the incinerator. A duct 24 is connected to the upper part of the incinerator.

The heat insulating wall 11 of the free board 14 is
At a certain height, the inner surface has a membrane structure covered with a refractory material, and is configured to absorb heat from a gas layer through a wall surface. The vapor evaporated by the membrane is stored in the steam reservoir 2
5, and the steam recovers the heat of the exhaust gas by the super heater 26 and is sent to an inlet header 47 of a heat transfer tube 46 described later. After the exhaust gas is deprived of heat by the super heater 26, it is further evaporated by an evaporator 28 having the same structure as the membrane of the furnace wall, a feed water heater 29 for avoiding low-temperature corrosion, and an air heater 30 for combustion air. Deprived of heat. Then, after being cooled by the gas cooler 32, the dust is removed by the bag filter 34, and is exhausted from the chimney through the exhaust fan 36.

Next, the structure of the bottom of the incinerator 10 is shown in FIG.
A description will be given based on FIG.

At the center of the furnace bottom in the left-right direction, a first dispersion plate 38 is provided.
The second dispersion plate 40 is disposed on both left and right sides of the first dispersion plate 38, and both the second dispersion plates 40 are adjacent to the heat insulating wall (apparatus main body side wall) 11. First dispersion plate 38
And the second dispersion plate 40 are horizontally separated from each other, and this portion serves as an incombustible discharge portion 42. Below the incombustible discharge section 42, an incombustible extractor 44 is provided.
The incombustibles extraction device 44 is provided with the incombustibles discharge section 42.
It has a built-in screw conveyor that transports the sand containing incombustibles derived from the outside to both left and right sides.

Here, the first dispersion plate 38 is inclined in a mountain shape so as to become lower toward the left and right non-combustible material discharge portions 42, and the second dispersion plate 40 is also inclined toward the non-combustible material discharge portion 42. It is inclined in the direction of lowering. These inclination angles may be set as appropriate, and specifically, 15
The angle is preferably not less than 35 ° and not more than 35 °.

Above both second dispersion plates 40, a plurality of heat transfer tubes (heat recovery means) 46 are juxtaposed at equal intervals in the depth direction of FIG. 1 (vertical direction in FIG. 2). Each heat transfer tube 46 penetrates the lower part of the heat insulating wall 11 to the side, faces the inside of the furnace, meanders on the second dispersion plate 40, and raises the heat insulating wall 1 above the penetrating part.
1 is drawn out of the furnace, and both ends are
Header 47 and outlet header 4 extending in the depth direction
8 respectively. Then, the steam sent from the super heater 26 to the inlet header 47 flows through the heat transfer tube 46 as an incineration heat recovery medium, and is recovered by the outlet header 48.

An air diffuser (partition member) 50 for dividing the fluidized bed 12 into a main combustion part and a heat recovery part is provided in the furnace. Each diffuser tube 50 includes an upper portion 51 located above the heat transfer tube 46 and a heat transfer tube 46 from the upper portion 51.
And an upright portion 52 extending in a substantially vertical direction through the sides of the upper portion 51 and reaching the second distribution plate 40. A number of gas injection holes are formed in the side surface of the tube wall of the upper portion 51 and in the vicinity thereof. .

The upper portion 51 is inclined so as to become lower toward the incombustibles discharge portion 42, and the upper surface of the fluidized bed 12 is located slightly above the upper portion 51.
The setting of the above-mentioned inclination angle is free, but specifically, it is preferably 5 ° or more and 35 ° or less.

A baffle (partition member) 54 made of a refractory material, a jacket, or the like is provided around an intermediate portion of the upright portion 52.
Are arranged. A minute gap 55 is secured between the baffles 54, and sand particles can flow through the gap 55 slightly.

The distance between the diffuser tubes 50 is determined by the heat transfer tubes 4.
6 is set to be equal to the arrangement interval of the air diffusion tubes 5, but the air diffusion tubes 5 are larger than the heat transmission tubes 46 by the diameter of the air diffusion tubes 50.
The gaps between the heat transfer tubes 46 are smaller than the gaps between the heat transfer tubes 46. The gap between the air diffusers 50 is a baffle 54.
It is also smaller than the vertical distance between the first and second dispersion plates 40 (ie, the exit width of the heat recovery unit).

A plurality of fluidizing gas injection holes are formed in the dispersion plates 38 and 40, a plurality of gas chambers 41 b are provided below the first dispersion plate 38, and a plurality of gas chambers 41 b are provided below the second dispersion plate 40. The gas chambers 40a, 41, 40b, and 40c are arranged side by side in the left-right direction, and the gas chamber and the dispersion plate constitute an air diffuser.

Of the above gas chambers, the gas chambers 40b and 40c located below the heat recovery unit and the gas chamber 41 to which the air diffuser 52 is connected are connected via a pipe 57A to a primary air supply source. An air blower (air supply means) 56A is connected, and the fluidizing gas (air) discharged from the primary air blower 56 is directly used as the fluidizing gas injection port of the second dispersion plate 40 or the fluidizing gas of the diffuser tube 52 tube wall. The injection is performed from the injection port toward the fluidized bed 12 in the furnace.

On the other hand, the gas chamber 40a, which is closer to the incombustible discharge portion 42 than the gas chamber 41, and the gas chamber 41b below the first dispersion plate 38 are connected to the primary chamber via a pipe 57B and a mixer 58. A primary air blower (air supply means) 56B similar to the air blower 56A is connected, and an oxygen generator (oxygen adding means) 60 including a PSA device or the like is connected to the mixer 58 via a buffer tank 59. I have.
Then, air supplied from the primary air blower 56B is supplied from the oxygen generator 60 to the buffer tank 59.
High-purity oxygen gas supplied through the gas chamber 40a, 41 is added as the oxygen-rich gas by the mixer 58.
b. Here, the oxygen-rich gas supplied to the gas chamber 41 is injected into the fluidized bed 12 from a number of fluidizing gas injection ports provided on the tube wall of the diffuser 52, and the fluidized gas is injected from the gas chamber 40a. The oxygen-rich gas ejected through the ejection port is ejected in a horizontal direction toward the incombustibles discharge portion 42 and passes near the surface of the baffle 54 facing the first dispersion plate 38 side.

Further, piping 57A connected to each gas chamber,
A damper (not shown) for adjusting the flow rate of the fluidizing gas flowing in each pipe 57 is provided in the middle of 57B, and the fluidizing gas injection amount can be adjusted for each pipe 57 using this damper.

In this embodiment, the injection amount of the fluidizing gas from the gas chamber 41b near the incombustible substance discharge portion 42 among all the gas chambers is basically set relatively large, and the first dispersion plate 3
The heat transfer tubes 46 in the central portion of the chevron 8 and the second distribution plate 40
The fluidizing gas injection amount from the gas chamber 41 located at the lower part of the nozzle is set relatively small. In order to set such an injection amount, as shown by a white arrow in FIG. 1, sand particles rise near the side of the baffle 54 on the side of the main combustion section, and the central side of the furnace and the upper side of the air diffuser 50. Flows that overflow to the 51 side and settle are formed.

Next, the operation of this device will be described.

First, wastes (objects to be treated) such as municipal solids introduced from the incineration material introduction port 16 fall into the fluidized bed 12 (in the main combustion section) on the first dispersion plate 38 and burn. In the fluidized bed 12, the sand particles that have risen near the baffle 54 overflow into the central part of the furnace and the upper part 51 of the diffuser 50 and settle.

More specifically, the particles overflowing to the upper portion 51 pass through the gap between the upper portions 51 and pass through the baffle 54.
After sinking between the heat transfer tubes 46 in the heat recovery portion sandwiched between the heat transfer tube 46 and the heat insulating wall 11, and applying incineration heat to the heat transfer tubes 46 (ie, after the heat transfer tubes 46 recover the incineration heat), the second It slides down along the inclined surface of the dispersion plate 40 toward the incombustible discharge part 42. Further, the particles overflowing to the center of the furnace settle down as they are at the center of the chevron of the first dispersion plate 38, and also slide down along the inclined surface of the first dispersion plate 38 toward the incombustible substance discharge portion 42. Here, since a strong fluidizing gas is injected from the gas chamber 41b immediately before the incombustible discharge part 42, some sand particles are pushed up by the fluidizing gas and recirculated to the main combustion part. Then, the other sand particles fall into the incombustible material discharge section 42 together with the incombustible material (solid matter), and are carried out to both left and right outer sides by the incombustible material extracting device 44. This output is sieved,
Only fine sand particles are resupplied to the fluidized bed 12.

Here, the fluidizing gas injected into the main combustion section through the gas chambers 41b and 40a is supplied to the primary air blower 56.
Since the oxygen-rich gas is obtained by adding high-purity oxygen gas to the gas discharged from B, the combustion in the fluidized-bed main combustion section is promoted more than in the conventional case where the air is directly injected, and Burn rate increases. Then, the heat generated here is transmitted to the heat transfer tube 46 in the heat recovery unit via the fluidized bed 12, thereby increasing the heat recovery efficiency through the heat transfer tube 46.

Next, a second embodiment will be described with reference to FIGS.

In this embodiment, an incombustible discharge port 14 is provided at the center of the bottom of the apparatus, and a first dispersing plate B1 and a second dispersing plate B2 are disposed on the left and right sides thereof. And
A partition member 54 is provided upright at a position near the incombustible discharge port 14 on the second dispersion plate B2, and the fluidized bed 12 is divided into a main combustion section on the left side in FIG. It is divided into a heat recovery section. This partition member 54
The pillars 53 are intermittently arranged at the lower part of the
3, a fluidized bed communication passage 28 that connects the main combustion section and the heat recovery section is formed.

The first dispersing plate B1 and the second dispersing plate B2 are each inclined toward the incombustible discharge port 14 and have a valley shape as a whole, and the gas chamber 4 is disposed below both the dispersing plates B1 and B2.
3a, 43b, 43c, 43d are provided.

The gas chamber 43a is formed below both the dispersing plates B1 and B2, and faces the region below the partition member 54 in the second dispersing plate B2 and substantially the entire region of the first dispersing plate B1. The gas chamber 43b is formed only below the outer portion of the second dispersion plate B2, that is, below the heat recovery section where the heat transfer tubes 46 are provided. The gas chamber 43c is formed only below the portion located in the vicinity of the incombustible material outlet 14 in the first dispersion plate B1, and the gas chamber 43d is formed in the vicinity of the incombustible material outlet 14 in the second dispersion plate B2. It is formed only below the portion where it is located.

Each of the dispersion plates B1 and B2 has a gas injection port for communicating the fluidized bed 12 above and the gas chamber below. However, FIG. 5 shows the gas chamber 43 for convenience.
Only the gas injection ports 62 and 64 facing c and 43d are shown. As shown in this figure, the arrangement position of the first gas injection ports 62 is orthogonal to the arrangement direction of the two dispersion plates B1 and B2 (the horizontal direction in FIG. 5) with respect to the arrangement position of the second gas injection ports 64. It is set at a position shifted in the direction (vertical direction in FIG. 5). The partition member 54 also has the gas chamber 43a.
A first fluidizing gas injection port 54a is formed which communicates with the fluidizing gas injection port 54a.

The primary air blower 56A shown in the first embodiment is directly connected to the gas chamber 43a.
The air discharged from the primary air blower 56A passes through the gas chamber 43a and is used as a fluidizing gas as it is in the first dispersion plate B.
1 is injected upward. Similarly, a high-speed primary air blower 56 is provided in the gas chambers 43c and 43d.
C is connected, and the air discharged from the high-speed primary air blower 56C passes through the gas chamber 43c as it is to the first air blower.
The second dispersion plate B is injected as a high-speed gas from the first dispersion plate B1 through the gas chamber 43d.
2 is injected.

On the other hand, the gas chamber 43b contains the mixer 5
The primary air blower 56B also shown in the first embodiment is connected to the mixer 58 via a buffer 8, and an oxygen generator (oxygen adding means) 60 such as a PSA device is connected to the mixer 58 via a buffer tank 59. ing. Then, high-purity oxygen gas supplied from the oxygen generator 60 via the buffer tank 59 to the air supplied from the primary air blower 56B is added by the mixer 58, and the gas is supplied as the oxygen-rich gas into the gas chamber. 43b, and the second dispersion plate B
It is designed to be injected upward from 2.

Here, the injection speed of the first high-speed gas and the second high-speed gas by the high-speed primary air blower 56C is set to be higher than the injection speed of the other fluidizing gas. Further, the first high-speed gas is injected obliquely upward from the first distribution plate B1 to above the second distribution plate B2, and the second high-speed gas is injected from the second distribution plate B2 to above the first distribution plate B1 (in detail). The direction of the two injection ports 62 and 64 is set so that the nozzles are injected obliquely upward (toward the partition member 54 described later). Further, the shape and arrangement position of the partition member 54 are set so that the partition member 54 deviates from the direction in which the high-speed gas is injected from both the injection ports 62 and 64. It is formed in a substantially L-shape.

Next, the operation of this device will be described.

First, an object to be processed, which has been input from the upper input port outside the figure, falls into the fluidized bed 12 on the first dispersion plate B1.
The fluidized bed 12 is a moving bed that settles in a light bubble layer state by the injection of the oxygen-rich gas from the gas chamber 43a, where the primary combustion (coarse combustion) of the combustibles in the object to be treated is performed. Then, the non-combustible material sinks and is discharged from the non-combustible material discharge port 14.

Here, the fluidized bed 12 constitutes a main combustion section, and oxygen-rich gas having an oxygen gas concentration higher than that of air is injected from the first dispersion plate B1 into the main combustion section. Accordingly, the combustion of the object to be treated is promoted, and the combustion rate in the fluidized bed 12 is increased.

The non-combustible substance (mainly carbon) is supplied to the fluidized bed 12
And gradually moves to the incombustible discharge port 14 along the slope, but flows upward while avoiding the partitioning member 54 by the first high-speed gas injected from the gas injection port 62 in front of it. The fluidized bed 1 which is blown up with the particles and exceeds the partition member 54 and is on the heat recovery section side (right side in FIGS. 4 and 5).
The combustion heat generated in the main combustion section is transmitted to the heat recovery section using the fluidized bed 12 as a medium. The fluidized bed 12 in this heat recovery section is also a moving bed that settles in a light bubble layer state, but only normal air is injected into this heat recovery section, and combustion is slow by that amount. The carbon is burned slowly and completely.

The object to be processed, which has been turned into ash by the combustion, passes through the fluidized bed communication passage 28 below the partitioning member 54 to the non-combustible material discharge port 14 together with the fluidized particles, and is injected obliquely upward on the near side. The gas is blown up to the free board (the space above the fluidized bed) by the second high-speed gas, and is discharged together with the exhaust gas from the outlet at the top of the furnace. The high-temperature flowing particles blown up together with the ash then fall and return to the main combustion section, and thereafter repeat the substantially figure-shaped circulation in the above-described manner (see the broken arrows in FIG. 1). This circulation promotes the overall soaking.

The moisture flowing in the heat transfer tube 46 becomes saturated steam or superheated steam by heat exchange with the exhaust gas, and is guided out of the apparatus. Thereby, the heat of the heat recovery unit is recovered.

* Experimental data FIG. 6 shows a case where air is directly injected from the gas chamber 43b to the heat recovery unit and a case where oxygen is added to the air before injection in the apparatus shown in the second embodiment ( The figure shows the results of measuring the combustion rate in a sand layer (fluidized bed) for the final oxygen gas concentration of about 25%). Here, the burning rate in the sand layer is (heat amount generated by burning in the sand layer) / ｛(heat amount generated by burning in the sand layer).
+ (The amount of heat generated by combustion outside the sand layer)｝. FIG. 7 shows the result of measuring the relationship between the burning rate in the sand layer and the heat recovery amount in the sand layer.

From FIG. 6, it can be seen that by adding high-purity oxygen gas to the gas to be injected into the main combustion section in advance, the burning rate in the sand layer is increased, and the effect is remarkable especially when the low calorific value of the waste is high. I can understand. From FIG. 7, it can be understood that the higher the combustion rate in the sand layer, the greater the amount of heat recovery in the sand layer. Therefore, by the addition of the oxygen gas,
It can be concluded that the amount of heat recovery in the sand layer portion can be increased, thereby significantly increasing the heat recovery efficiency.

The present invention is not limited to the above-described embodiment, but may take the following forms as examples.

(1) The oxygen gas concentration in the oxygen-rich gas is as follows:
What is necessary is just to set suitably in the range higher than the oxygen gas concentration in air (about 21%). However, when the oxygen gas concentration is 30
%, The combustion in the fluidized bed 12 is excessively promoted, and it has been found by experiments that the heat easily damages the refractory material constituting the heat insulating wall 11 and the partition member 54. More preferably, the oxygen gas concentration is set to a value of less than 30%. The setting of such oxygen gas concentration is as follows:
For example, in the case of the apparatus according to the first embodiment, the adjustment can be performed freely by adjusting the flow rate of oxygen gas to the mixer 58.

(2) In the method according to the first aspect of the present invention, oxygen-rich gas may be injected over the entire apparatus. However, even if the oxygen-rich gas is injected in the heat recovery section instead of the main combustion section, the degree of contributing to the promotion of combustion is low. Therefore, by stopping the addition of oxygen gas to this heat recovery section, the cost is further reduced. Can be reduced.

(3) In the present invention, the component other than the oxygen component in the fluidizing gas is not particularly limited. For example, an inert gas such as argon mixed with a suitable amount of oxygen gas may be used.
However, as shown in the above embodiments, air is directly injected into the heat recovery unit, and a gas obtained by adding a small amount of oxygen gas to air is injected into at least a part of the main combustion unit. By doing so, there is an advantage that the above-mentioned excellent effects can be obtained with an inexpensive configuration that makes full use of inexhaustible air.

(4) In the above embodiment, the fluidizing gas is injected from the fluidizing gas injection port provided on the dispersion plate. However, instead of the dispersion plate, a number of diffuser tubes are arranged in parallel. The present invention can also be applied to an apparatus that injects a fluidizing gas upward from a fluidizing gas injection port provided on the pipe wall of these diffuser tubes.

[0061]

As described above, according to the present invention, the following effects can be obtained.

The method according to claim 1, wherein the fluidized gas injected from at least a part of the air diffuser to the fluidized bed is an oxygen-rich gas having an oxygen gas concentration higher than the oxygen gas concentration in air. Therefore, compared to the conventional case where air is directly injected as a fluidizing gas, it is possible to promote the combustion of the object to be treated in the fluidized bed and increase the combustion rate in the fluidized bed. With a simple configuration, there is an effect that the heat recovery efficiency of the heat recovery means from the inside of the fluidized bed can be increased.

In particular, by increasing only the oxygen gas concentration of the fluidizing gas with respect to the main combustion section to increase the combustion rate exclusively in the main combustion section,
By generating a lot of heat in the main combustion section, this heat can be recovered by the heat recovery means in the fluidized bed as a medium, and by suppressing the oxygen gas concentration of the fluidizing gas injected to the heat recovery section to be low,
Costs can be further reduced.

Further, in the method and apparatus according to the third and sixth aspects, a gas obtained by adding oxygen gas to air as the fluidizing gas is injected into at least a part of the main combustion section, However, since the air is directly injected as the fluidizing gas, the heat recovery efficiency can be improved by an inexpensive means that makes full use of inexhaustible air.

Further, by setting the oxygen-rich gas concentration of the oxygen-rich gas to be less than 30%, wasteful consumption of expensive oxygen is prevented and excessive combustion is promoted. There is an effect that the heat recovery efficiency can be appropriately increased without damaging the device.

[Brief description of the drawings]

FIG. 1 is a sectional front view showing a main part of a fluidized bed heat recovery device according to a first embodiment of the present invention.

FIG. 2 is a partial cross-sectional plan view showing the main part.

FIG. 3 is an overall configuration diagram of the fluidized bed heat recovery device.

FIG. 4 is a sectional front view showing a main part of a fluidized bed heat recovery device according to a second embodiment of the present invention.

FIG. 5 is a sectional view taken along line AA of FIG. 4;

FIG. 6 is a graph showing the relationship between the lower calorific value of waste and the burning rate in a sand layer in the case where oxygen is not added and the case where oxygen is added in the second embodiment.

FIG. 7 is a graph showing a relationship between the burning rate in the sand layer and the heat recovery amount in the sand layer.

FIG. 8 is a sectional front view showing an example of a conventional fluidized bed heat recovery device.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 10 Incinerator 12 Fluidized bed 38 1st dispersion plate (constituting a diffuser) 40 2nd dispersion plate (constituting a diffuser) 40a, 40b, 40c, 41, 41a, 43a, 43
b, 43c, 43d Gas chambers (constituting air diffuser) 46 Heat transfer tube (heat recovery means) 50 Air diffuser tube (partition member) 54 Baffle (partition member) 56A, 56B, 56C Primary air blower (air supply means) 60 Oxygen Generator (oxygen adding means)

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) F23G 5/30 F23G 5/46 F23L 7/00 F23C 11/02

Claims (7)

(57) [Claims] 1. A fluidized bed comprising fluidized particles flowing upon receiving a fluidizing gas injected from the diffuser is formed on an air diffuser provided at the bottom of the apparatus main body, and the fluidized bed is formed in the fluidized bed. In a fluidized bed heat recovery apparatus provided with a heat recovery means for recovering heat generated by incineration of an object to be processed in a fluidized bed, an oxygen gas concentration is air as a fluidizing gas injected from at least a part of the air diffuser. A method for operating a fluidized-bed heat recovery apparatus, characterized by injecting an oxygen-enriched gas higher than the oxygen gas concentration in the inside. 2. A fluidized bed composed of fluidized particles flowing upon receiving a fluidizing gas injected from the diffuser is formed on a diffuser provided at the bottom of the apparatus body, and the fluidized bed is formed in the fluidized bed. A heat recovery unit is provided for recovering heat generated by incineration of the object in the fluidized bed, and the fluidized bed is provided with a heat recovery unit provided with the heat recovery unit and a main combustion in which the object is administered. In the fluidized-bed heat recovery apparatus provided with a partition member for partitioning the gas into a portion, at least a part of the main combustion portion has an oxygen gas concentration higher than the oxygen gas concentration in air as the fluidizing gas. A method for operating a fluidized bed heat recovery apparatus, comprising injecting oxygen gas and injecting a gas having an oxygen concentration equal to or less than an oxygen gas concentration in air as the fluidizing gas to the heat recovery unit. 3. A method for operating a fluidized-bed heat recovery apparatus according to claim 2, wherein a gas obtained by adding oxygen gas to air as said fluidizing gas is injected into at least a part of said main combustion section. A method for operating a fluidized bed heat recovery apparatus, wherein air is directly injected as the fluidizing gas to the heat recovery section. 4. The method for operating a fluidized-bed heat recovery apparatus according to claim 1, wherein the oxygen-rich gas has an oxygen gas concentration of less than 30%. Driving method. 5. A fluidized bed composed of fluidized particles flowing upon receiving a fluidizing gas injected from the diffuser is formed on a diffuser provided at the bottom of the apparatus body, and the fluidized bed is formed in the fluidized bed. A heat recovery unit is provided for recovering heat generated by incineration of the object in the fluidized bed, and the fluidized bed is provided with a heat recovery unit provided with the heat recovery unit and a main combustion in which the object is administered. In the fluidized bed heat recovery device provided with a partitioning member for partitioning the gas into an oxygen gas concentration in the air as the fluidizing gas from the air diffuser to at least a part of the main combustion portion. A first injection means for injecting a higher oxygen-enriched gas, and a second injection means for injecting a gas having an oxygen concentration equal to or lower than the oxygen gas concentration in air as the fluidizing gas from the air diffuser to the heat recovery unit. That it has injection means. A fluidized bed heat recovery device. 6. The fluidized bed heat recovery apparatus according to claim 5, wherein the first injection means is an air supply means for supplying air to a gas injection section of the diffuser, and the air is injected from the gas injection section. Oxygen adding means for adding oxygen gas to the air before the air is supplied, and air supply means for directly supplying air to the gas injection unit of the air diffuser as the second injection means. Fluidized bed heat recovery equipment. 7. The fluidized bed heat recovery apparatus according to claim 5, wherein the first injection means is configured so that an oxygen gas concentration of the oxygen-rich gas is less than 30%. Heat recovery device.