JP2671078B2 - Fluidized bed combustion device - 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 combustion apparatus suitable for burning and incinerating waste such as rubber containing sulfur, waste plastics such as vinyl chloride, or synthetic rubber such as chloroprene. .

[0002]

2. Description of the Related Art Conventionally, a fluidized bed combustion apparatus such as a fluidized bed incinerator that burns and incinerates wastes such as rubber containing sulfur and waste plastics such as vinyl chloride has an exhaust gas discharge port at the upper part. In the combustion chamber, air is used to fluidize a fluid medium such as sand to form a high-temperature fluidized bed, and the waste is charged into the fluidized bed for combustion, and a space portion above the fluidized bed in the combustion chamber, That is, volatile components such as carbon monoxide, which is generated by thermal decomposition in the fluidized bed in the freeboard and is discharged together with combustion exhaust gas from the fluidized bed, and hydrocarbons such as methane, ethane, and ethylene, and the fluidized material. Unburned components such as a part of solids similarly discharged from the floor are burned by supplying secondary air.

The above-mentioned freeboard combustion is also referred to as two-stage combustion. In such two-stage combustion, the air for combustion (so-called primary air) is reduced in the fluidized bed to reduce the oxygen concentration. Carbon monoxide generated in the fluidized bed by injecting secondary air above the freeboard in order to reduce the amount of nitrogen oxides produced by burning it in a reducing atmosphere and at a relatively low temperature. It is designed to burn unburned components such as.

[0004]

In the case of rubber containing sulfur and waste plastics such as vinyl chloride, gas such as carbon monoxide and volatile matter generated by thermal decomposition by combustion in a fluidized bed is used. The rate at which the body is burned on the freeboard is high, and the calorific value in these burns
Is high. Therefore, the freeboard burns these unburned substances with high combustion efficiency to reduce the amount of unburned substances emitted from the combustion device to effectively recover heat and to discharge harmful substances such as carbon monoxide. It is necessary to prevent pollution and effectively prevent pollution.

However, in the freeboard formed as a space above the fluidized bed as described above,
The combustion exhaust gas is simply a gas flow directed upward, and even if the secondary air is supplied to burn the unburned matter, the secondary air and the combustion exhaust gas cannot be mixed well,
Therefore, there is a limit to burn the unburned matter that is lifted by being entrained in the combustion exhaust gas while maintaining high combustion efficiency. Further, for this reason, there is a problem that reduction of carbon monoxide and reduction of nitrogen oxides are not performed effectively while maintaining high combustion efficiency.

On the other hand, when wastes such as vulcanized rubber containing sulfur content and waste plastics such as vinyl chloride are burned, sulfur oxides such as sulfur dioxide and the like are contained in the combustion exhaust gas. Contains harmful gases such as hydrogen chloride gas,
At the same time, it is necessary to remove these harmful substances to prevent pollution.

The present invention has been made in view of the above problems, and reduces the carbon monoxide by burning wastes such as rubber containing sulfur and waste plastics such as vinyl chloride with high efficiency. An object of the present invention is to obtain a fluidized bed combustion apparatus that can effectively reduce the amount of nitrogen oxides and nitrogen oxides and can effectively perform desulfurization and / or dechlorination of combustion exhaust gas.

[0008]

In order to achieve the above object, the present invention provides (1) a fluidized bed combustion apparatus for combusting an object to be burned in a high temperature fluidized bed formed by fluidizing a fluidized medium with air. In the fluidized bed combustor, a material to be burned is charged and burned 1
A primary combustion chamber including a secondary fluidized bed and a first freeboard above the secondary fluidized bed, and a secondary fluidized bed formed by fluidizing at least a part of the primary combustion chamber and secondary air in the lower portion. And a secondary combustion chamber having a second freeboard on the upper side thereof, and the second freeboard and the first freeboard are communicated with the secondary combustion chamber, and combustion of the primary combustion chamber The exhaust gas inlets through which the exhaust gas flows are provided facing each other,
An upper fluid chamber consisting of a third fluidized bed for desulfurization and / or dechlorination of combustion exhaust gas and a third freeboard above it is provided above the secondary combustion chamber via a gas dispersion plate, and above the upper fluid chamber. An exhaust gas outlet was provided and configured.

(2) In the structure of (1) above, a heat transfer tube is embedded in the secondary fluidized bed of the secondary combustion chamber, and the heat transfer tube is used as a superheater. .

[0010]

In the structure of (1), the combustion object such as rubber containing sulfur and waste plastic such as vinyl chloride has a high temperature.
It is put into the next fluidized bed and burned in a low oxygen atmosphere, and from the fluidized bed is burned together with unburned components such as volatile components of hydrocarbon gas such as carbon monoxide and methane generated in the fluidized bed, and others. Exhaust gas is discharged and goes up the first freeboard. Then, the combustion exhaust gas that has risen from the first freeboard flows into the second freeboard from the exhaust gas inlet provided opposite to the secondary combustion chamber, where the combustion exhaust gases collide with each other and are mixed. Further, the secondary air discharged from the secondary fluidized bed located under the second freeboard collides with and collides with each other, and the combustion exhaust gas and the secondary air are mixed very well.

Further, due to the collision of the exhaust gases with each other on the second freeboard, some solid unburned components and scattered fluidized medium particles generated in the primary fluidized bed are stalled, so
It falls into the next fluidized bed and is captured, and the solid unburned matter is burned there. Then, the combustion exhaust gas discharged from the secondary combustion chamber flows into the upper fluid chamber provided above it through the gas dispersion plate, and is subjected to desulfurization and / or dechlorination by the tertiary fluidized bed there. In the tertiary fluidized bed, an adsorbent for desulfurization and / or dechlorination of limestone, quick lime, etc. is used as a fluid medium. The combustion exhaust gas having this effect is discharged from the exhaust gas outlet to the outside of the apparatus.

However, in the second freeboard of the secondary combustion chamber, the combustion exhaust gas and the secondary air are mixed very well as described above, so that volatile components such as carbon monoxide and methane are not contained. The fuel is burned with high efficiency. Further, the desulfurization and / or dechlorination of the combustion exhaust gas is effectively performed in the upper flow chamber. Therefore, the reduction of carbon monoxide and the reduction of nitrogen oxides are performed while maintaining a high combustion rate, the combustion efficiency is high, and desulfurization and / or dechlorination can be effectively performed to prevent pollution. A fluidized bed combustor is obtained.

In the configuration of (2), the heat transfer tube is installed so as to be buried in the secondary fluidized bed, and by using this heat transfer tube as a superheater, the heat transfer tube is provided above the second fluidized bed.
It is completely separated from corrosive exhaust gas such as hydrogen chloride gas contained in the combustion exhaust gas of the freeboard part of the above, and its pipe wall temperature as a superheater becomes as high as 500 to 600 ° C under the condition that corrosion by hydrogen chloride gas is severe. Even if it exists, its corrosive effect is mitigated or prevented, it can be used as a superheater, and heat can be effectively recovered.

Further, the temperature of the second freeboard can be adjusted by this heat transfer tube, and it is possible to prevent an abnormal temperature rise of combustion gas when burning waste plastic such as vinyl chloride having a high calorific value. It is possible to prevent the (ash) from adhering to the inner wall of the furnace such as a gas dispersion plate by clinker formation.

[0015]

Next, an embodiment of the present invention will be described in detail with reference to the drawings. 1 is a longitudinal sectional view showing an embodiment of a fluidized bed combustion apparatus according to the present invention, and FIG. 2 is a side view (partial side sectional view) taken along the line II-II of FIG. In the fluidized bed combustion apparatus 1, an air chamber 2 is located at the lowermost portion, a primary combustion chamber 10 is located at an upper portion thereof surrounded by a furnace wall 16, and at least a lower portion thereof is located in the primary combustion chamber 10. Thus, the secondary combustion chamber 20 is positioned, and the upper flow chamber 30 is positioned above the secondary combustion chamber 20 by being defined by the gas dispersion plate 40, and is located above the freeboard (third freeboard) of the upper flow chamber 30. A waste heat recovery device 60 is installed, and an exhaust gas discharge port 35 is provided downstream thereof.

The structure of the fluidized bed combustion apparatus 1 will be described in more detail. The furnace wall 16 of the primary combustion chamber 10 and the air chamber 2 is formed as a water cooling wall by connecting a number of cooling pipes 16a to each other by plates, and a refractory material 16b is formed on the inner surface of the water cooling wall.
It is configured by being attached. At the bottom of the primary combustion chamber 10, an air dispersion plate 15 that is inclined so as to become lower toward the center is attached, and separates the lowermost air chamber 2. A cooling pipe 16a is laid inside the air dispersion plate 15, and a large number of air dispersion pipes (not shown) are attached so as to project from the air dispersion plate 15 at the upper portion. The ejection hole is the combustion device 1 in FIG.
The high temperature air (primary air) is directed from the air chamber 2 to the primary combustion chamber 10 through this air ejection hole.
It is configured to be distributed and supplied into the inside.

Each of the cooling pipes 16a is collected in a header (not shown) and connected to a steam drum. A groove-shaped incombustible discharge port 3 is formed in the center of the air dispersion plate 15, which is the lowest position, and the incombustible discharge port 3 divides the air chamber 2 into left and right sides in FIG. Incombustible discharge port 3
Although not shown, the fluidized medium FM and the incombustible material are burned by the combustion device 1
A fluid medium circulating and transporting device for removing the incombustibles together with the screen device to separate and remove the fluid medium FM and returning only the fluid medium FM to the combustion device 1 through the fluid medium supply port 25 again is connected and installed. Although not shown, high temperature air supply pipes and auxiliary burners are installed in the left and right air chambers 2, respectively.

The air dispersion plate 15 is provided in the primary combustion chamber 10.
A primary fluidized bed 11 formed by fluidizing a fluid medium FM made of an adsorbent for desulfurization and dechlorination such as limestone having a particle size of 0.5 to 1.0 mm with high temperature air is positioned on A first freeboard 12 is located above the primary fluidized bed 11. A waste feeder 14 is attached to the top furnace wall 16 of the primary combustion chamber 10 at the left and right positions in FIG. 1, and the waste WM is made of rubber vulcanized from the waste inlet 13 or waste plastic such as vinyl chloride. Are taken into the primary combustion chamber 10 and put into the primary fluidized bed 11.

In the primary combustion chamber 10, the secondary combustion chamber 20 is provided with the secondary fluidized bed 21 below it as the lowest portion, and the lower portion of the second freeboard 22 is located above it. Has been. The secondary combustion chamber 20 is integrated with a furnace wall of an upper flow chamber 30 which will be described later, and the furnace wall 50 is constituted by a vertical water cooling wall. The pipes 50a are arranged laterally at a predetermined interval and are formed by connecting adjacent water cooling pipes 50a with a narrow plate 50d. The bottom wall 26 that supports the lowest secondary fluidized bed has a substantially V-shaped cross section as shown in FIG. 1, and is formed by covering the outside of the bottom water cooling wall with a refractory material. 50b and 50c are headers of the water cooling pipe 50a.

Inside the bottom wall 26, a plurality (five in this embodiment) of diffuser tubes 24 for supplying secondary air are horizontally arranged, and the secondary air SA is jetted and dispersed from the diffuser tubes. The fluid medium FM, which has been supplied from the fluid medium (limestone) supply port 23 in the upper portion to the later-described upper fluid chamber 30 and then dropped through the gas dispersion plate 40, is fluidized to be the secondary fluidized bed 21.
Is formed.

Inside the bottom wall 26, a plurality of heat transfer tubes 25 for heat recovery are horizontally installed above the air diffuser tube 24 so as to be located in the secondary fluidized bed 21.
Is configured as a superheater. This superheater is connected to a steam drum (not shown), and saturated steam is supplied from this steam drum to the superheater, where it is converted into superheated steam. A part of the fluidized medium FM of the secondary fluidized bed 21 overflows from the top of the vertical wall of the bottom wall 26 and flows into the primary fluidized bed 11 below while flowing.

However, in the secondary combustion chamber 20, as shown in FIG. 1, a vertical side wall between the top of the vertical wall of the bottom wall 26 and the horizontal furnace wall 16 of the top of the primary combustion chamber 10 ( An exhaust gas inlet 23 into which the combustion exhaust gas of the primary combustion chamber 10 flows is provided opposite to each other in the vertical water cooling wall portion, and the exhaust gas inlet 23 is provided with the first freeboard 12 and the second freeboard 22. The first freeboard 12 and the second freeboard 22 are directly communicated with each other. As shown in FIG. 2, the exhaust gas inlet 23 has an opening 23a formed between the exhaust gas inlet 23 and the vertical water cooling pipe 26a so that the exhaust gas flows therein.

Second freeboard 22 of secondary combustion chamber 20
A gas distribution plate 40 is provided across the furnace above
An upper flow chamber 30 is formed on the upper part thereof. The gas dispersion plate 40 is configured such that a large number of straight gas dispersion pipes 41 are provided vertically and a large number of water cooling pipes 42 are laid at the bottom. A tertiary fluidized bed 31 is formed in the upper fluidized chamber 30 by fluidizing limestone FM as a desulfurizing and / or dechlorinating agent from the secondary combustion chamber 20 by the combustion exhaust gas dispersed by the gas dispersion plate 40. The third freeboard 32 is located above it. 3
The inner surface of the furnace wall 50 where the next fluidized bed 31 is formed is covered with a refractory material.

An opening is located on the third freeboard 32, and the above-mentioned fluid medium (limestone) is placed on the furnace wall (water cooling wall) 50.
A supply port 33 is provided, and an exhaust heat recovery device 60 including a heat transfer tube is installed in the exhaust gas flow passage above the supply port 33. Further, an exhaust gas discharge port 35 is provided at the downstream position thereof.

Next, the operation of the embodiment of the apparatus of the present invention having such a configuration will be described. At the lowermost part of the primary combustion chamber 10, the limestone fluidized medium FM is fluidized by the primary air PA supplied from the air chamber 2 through the air dispersion plate 15,
The secondary fluidized bed 11 is formed, and the fluidized medium FM is heated in the primary fluidized bed 11 by the high temperature primary air PA and combustion heat.
It is kept at a high temperature of 00 to 850 ° C. This primary fluidized bed 11
The right side in FIG. 1 is obtained by ejecting the primary air PA toward the central portion because the air ejection hole of the air dispersion pipe (not shown) is provided so as to be directed toward the central portion of the combustion device 1. The primary fluidized bed 11 is swirled to the right and flows, and the left primary fluidized bed 11 swirls to the left. At this time, the left and right primary fluidized beds 11 are respectively the secondary fluidized bed 2
1. The bottom wall 26 of the part formed by inclining upward from the central part of 1
Guided by, the turning is performed smoothly.

The primary fluidized bed 11 thus formed
The waste supply machine 14 supplies vulcanized rubber as waste WM and waste plastic such as vinyl chloride to the supply port 1.
It is dropped from 3 into the primary fluidized beds 11 on both the left and right sides, charged and burned. During this combustion, since the primary fluidized bed 11 is swirling in the direction toward the center, the fluidized medium F
The M and the waste WM are well agitated and mixed to be efficiently burned, and the iron scraps and the lump-shaped incombustibles contained in the waste are swirled by this swirling action, and the air dispersion plate 15 is located at the central portion. Since it is inclined so as to become lower toward the center, it is collected in the central portion and drops from the incombustibles discharge port 3 together with a part of the fluid medium FM, and is placed on an external fluid medium circulating and transporting device (not shown). The fluidized medium FM is removed by the screen device, is supplied again from the fluidized medium supply port 25 to the secondary fluidized bed 21 in the combustion device 1, and is used again.

In the primary fluidized bed 11, the amount of primary air PA is relatively small, that is, in a so-called reducing atmosphere, and
Combustion is performed with the combustion temperature kept relatively low, resulting in low NO
_x conversion is achieved. Combustion exhaust gas from the primary fluidized bed 11 is carbon monoxide (CO) generated by low oxygen concentration combustion from waste plastics such as rubber and vinyl chloride in the primary fluidized bed 11.
Generated by thermal decomposition of the waste plastic or the like,
Methane _(CH 4), ethane _{(C 2 H} 6), ethylene (C
₂ H ₄ ), etc., or unburned components consisting of some solid particles, etc., and the flying fluid medium FM, rises up the first freeboard 12, and some of these unburned components are The first freeboard 12 is burnt even while it is rising.

The combustion exhaust gas that has passed through the first freeboard 12 has a portion 2 which is provided in contact with the first freeboard 12 through the exhaust gas inlet 23 from the first freeboard 12. It flows into the second freeboard 22 of the next combustion chamber 20. Then, the inflow of the exhaust gas is performed from the first freeboards 12 on both sides of the primary combustion chamber 10 in FIG. 1 through the exhaust gas inlets 23 on both sides provided to face the secondary combustion chamber 20, In the figure,
The exhaust gas C ₁ flowing from the left inlet 23 and the exhaust gas C ₂ flowing from the right inlet 23 are the second freeboard 2
2 and collide with each other at 2
By combining the secondary air SA discharged upward from the secondary fluidized bed with each other, the three components are mixed very well.

Due to the good mixing due to the collision with the exhaust gas C ₁ , the exhaust gas C ₂ , and the secondary air SA, the gaseous unburned components such as carbon monoxide and volatile components are burned very efficiently and almost completely burned. Is carried out. The temperature of the second freeboard 22 is set to 900 to 950 ° C. by this combustion. Then, the unburned component consisting of a part of solid particles and the like contained in the combustion exhaust gas and the scattered fluid medium FM stall due to the above collision and fall into the secondary fluidized bed 21, and the solid unburned particles burn here. At the same time, the fluidized medium FM is used here as a fluidized medium.

The secondary fluidized bed 21 is formed by fluidizing the fluidized medium FM by the secondary air SA supplied from the air diffuser 24, and the fluidized medium itself heated in the tertiary fluidized bed 31 is the gas dispersion plate 40. By passing through the gas dispersion pipe 41 and falling, and by radiant heat due to combustion in the second freeboard 22 and by burning a small amount of some of the solid unburned particles, a predetermined temperature (for example, about 800 ° C.) is obtained. Be heated. Then, a part of the fluid medium FM of the secondary fluidized bed 21 overflows as described above and falls to the primary fluidized bed 11 to be used as the fluidized medium of the primary fluidized bed 11.

In the secondary fluidized bed 21, the heat of the secondary fluidized bed 21 is recovered by the heat transfer tube 25 as a superheater, and especially the secondary combustion chamber 20 is prevented by preventing an excessive temperature rise of the second freeboard 22. The temperature is adjusted and the heat is effectively recovered by being used as a superheater. Heat transfer tube 2
Since No. 5 is buried and installed in the secondary fluidized bed 21,
Since it is completely separated from the combustion exhaust gas containing a large amount of corrosive gas such as hydrogen chloride gas in the upper second freeboard 22 part, it is a superheater in which the wall temperature of the heat transfer tube becomes 500 to 600 ° C. However, it is possible to prevent corrosion by the corrosive gas.

In this embodiment, the heat transfer tube 25 as a superheater is provided at the second freeboard 22 immediately above the upper surface of the secondary fluidized bed 21 instead of at the position shown in the drawing. The heat can be recovered by providing it in a portion where the concentration of the secondary air SA is high and the concentration of the hydrogen chloride gas is diluted to prevent corrosion.

The high-temperature exhaust gas after the unburned materials are burned in the second freeboard 22 flows into a large number of gas dispersion pipes 41 of the gas dispersion plate 40 and is supplied into the upper flow chamber 30 from above. It On the gas dispersion plate 40, the fluid medium, which is limestone, is fluidized by the combustion exhaust gas, and the tertiary fluidized bed 3
1, where sulfur oxides such as sulfur dioxide and hydrogen chloride gas in the combustion exhaust gas react with quick lime (CaO) produced by calcining limestone, which results in desulfurization and / or dechlorination. Done.

By providing the upper fluidized chamber 30, even if unburned material remains in the secondary combustion chamber 20, it can be caught and burned in the tertiary fluidized bed 31 to complete combustion. Can be effectively done.

The combustion exhaust gas passing through the tertiary fluidized bed 31 is
The third freeboard 32 rises and flows into the exhaust heat recovery device 60, where the heat retained therein is recovered and the exhaust gas exhaust port 3
5 is discharged to the outside of the apparatus, and is further recovered by another exhaust heat recovery device such as an air preheater (not shown) and is also used for dust collection and the like.

Furnace wall 5 of secondary combustion chamber 20 and upper flow chamber 30
No. 0 has a vertical water cooling wall structure, the inner surface of which is exposed to the gas passage surface, and the gas dispersion plate 40 is provided with a water cooling pipe 42 facing the secondary combustion chamber 20. Is increased so that heat can be effectively recovered. In addition, as a result, the exhaust heat recovery unit such as the exhaust heat recovery device 60 provided in the upper portion is made small. And the furnace wall 50
Since the vertical water cooling wall does not face the primary fluidized bed 11, the radiant heat of the primary fluidized bed 11 is not absorbed by the vertical water cooling wall and the temperature of the primary fluidized bed 11 is effectively maintained. Also,
By adopting the vertical water cooling wall structure, it is possible to obtain a natural circulation type boiler having a simplified structure.

In this embodiment, the primary combustion chamber 10,
Since the secondary combustion chamber 20 and the upper flow chamber 30 are provided separately, it is possible to operate under optimum temperature conditions. For example, the primary combustion chamber 10 is operated to keep the temperature of the primary fluidized bed 11 low in order to reduce nitrogen oxides, and the secondary combustion chamber 20 burns unburned substances such as carbon monoxide to a high temperature. The temperature can be maintained, and the upper flow chamber 30 can be set to a temperature suitable for desulfurization and / or dechlorination.

Further, in this embodiment, the furnace walls 16 of the primary combustion chamber 10 and the air chamber 2 are water cooling walls, and the furnace wall 50 of the secondary combustion chamber 20 is also a water cooling wall. Since there is almost no difference, there is no difference in thermal expansion between the chambers. Therefore, a firm furnace wall can be constructed.

Further, in the apparatus of this embodiment, in FIG. 1, for example, by supplying the primary air only from the air chamber 2 on the right side to form the primary fluidized bed 11 on the right side only and performing half-way operation, the fluidized state is obtained. It is possible to perform a half load without changing. That is, in this half-face operation, the fluidized medium FM on the left side is stationary and the height is low, and the fluidized fluidized bed 11 on the right side is expanded and the height is high. This can be done by making the product of the overall apparent density and the height, that is, the layer pressure almost equal. If this half-way operation is performed, the amount of air can be reduced to half, which is economical.

As described above, in the apparatus of this embodiment, the rubber containing sulfur and the waste plastics such as vinyl chloride are burned with high efficiency to produce unburned carbon monoxide and the like, nitrogen oxides, and sulfur oxides. It is possible to effectively prevent pollution by preventing the discharge of harmful substances such as hydrogen chloride gas and the like to the outside of the device, and to effectively recover the heat retained in the combustion exhaust gas of the waste plastic having a high calorific value. it can.

[0041]

As described above, according to the present invention, by virtue of the constitution of claim 1, the combustion exhaust gas and the secondary air can be mixed very well in the secondary combustion chamber, It is possible to almost completely burn unburned components such as carbon monoxide and methane that are entrained in the combustion exhaust gas from the primary combustion chamber, and desulfurize and / or dechlorinate the combustion exhaust gas in the upper flow chamber. Can be effectively performed.
Therefore, wastes such as rubber containing sulfur and waste plastics such as vinyl chloride can be burned with high combustion efficiency to effectively reduce carbon monoxide and nitrogen oxides and effectively perform desulfurization and / or dechlorination. It is possible to obtain a fluidized bed combustion device that can effectively prevent the above.

According to the second aspect of the present invention, even when a waste such as waste plastic, which produces a corrosive gas such as hydrogen chloride gas by combustion, is burned, the corrosive environment caused by the corrosive gas is moderated. , Or corrosion can be prevented, and the heat transfer tube can be effectively used as a superheater, so that heat can be effectively recovered.

[Brief description of the drawings]

FIG. 1 is a vertical sectional view showing an embodiment of a fluidized bed combustion apparatus according to the present invention.

FIG. 2 is a side view (partial side sectional view) taken along the line II-II of FIG.

[Explanation of symbols]

 1 Fluidized Bed Combustor 10 Primary Combustion Chamber 11 Primary Fluidized Bed 12 First Freeboard 15 Air Dispersion Plate 20 Secondary Combustion Chamber 21 Secondary Fluidized Bed 22 Second Freeboard 23 Combustion Exhaust Gas Inlet 24 Diffuser 25 Heat transfer pipe (superheater) 27 Exhaust gas exhaust port 30 Upper fluid chamber 31 Third fluidized bed 32 Third freeboard 35 Exhaust gas exhaust port 60 Exhaust heat recovery device PA Primary air SA Secondary air

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification number Office reference number FI technical display location F23G 5/46 ZAB F23G 5/46 ZABB 7/12 ZAB 7/12 ZABZ

Claims (2)

(57) [Claims] 1. A fluidized bed combustor for combusting an object to be burned in a high temperature fluidized bed formed by fluidizing a fluidized medium with air, the object being burned into the fluidized bed combustor. A primary combustion chamber consisting of a primary fluidized bed and a first freeboard above it, and at least a part of which is located in this primary combustion chamber and fluidized by secondary air in the lower part to form 2 A secondary combustion chamber having a secondary fluidized bed and a second freeboard is provided above the secondary fluidized bed, and the secondary combustion chamber is connected to the second freeboard and the first freeboard to perform primary combustion. Exhaust gas inflow ports of the chamber are provided facing each other, and a third fluidized bed for desulfurization and / or dechlorination of the combustion exhaust gas is provided above the secondary combustion chamber via a gas dispersion plate and a third fluidized bed above the third fluidized bed. An upper flow chamber consisting of a freeboard is provided, and exhaust gas is above the upper flow chamber. A fluidized bed combustor characterized by being provided with an outlet. 2. A fluidized bed combustion according to claim 1, wherein a heat transfer tube is embedded in the secondary fluidized bed in the secondary combustion chamber, and the heat transfer tube is used as a superheater. apparatus.