JPH10306907A - Fluidized bed pyrolysis method and pyrolysis fuenace as well as treating device for matter to be burnt - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fluidized bed pyrolysis method and a pyrolysis furnace as well as a treating device for matters to be burnt, which are capable of recovering valuable metals in a fluidized bed pyrolysis furnace while restraining the oxidation of the valuable metals. SOLUTION: In a single tower type fluidized bed pyrolysis furnace 11, fluidizing medium FD is filled into a furnace equipped with a gas dispersing plate 112 in the bottom part thereof and gas is sent from the lower part of the gas dispersing plate 112 to fluidize the fluidizing medium FD while matters to be burnt are supplied into the fluidized bed under fluidized condition to gasify through pyrolysis. Such a fluidized bed pyrolysis furnace 11 is provided with a means for sending gas, containing no oxygen or the concentration of oxygen therein is low, from the lower part of the gas dispersing plate 112, and a blow tube 116, provided above the gas dispersing plate 112 at a position apart from the dispersing plate 112 by a predetermined distance to blow air or gas containing oxygen.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fluidized bed pyrolysis method and a pyrolysis furnace for pyrolyzing industrial waste, municipal solid waste, coal, etc., as combustibles, and a flammable gas generated by the pyrolysis. The present invention relates to an apparatus for treating a combustible, which burns ash containing combustibles and char at a high temperature and melts it.

[0002]

2. Description of the Related Art In recent years, the amount of municipal solid waste disposal has been increasing steadily, and it has become increasingly difficult to secure land for landfill disposal. In addition, groundwater is contaminated in landfill treatment, and under the situation where laws and regulations for preventing environmental pollution are being strengthened, studies are being made on, for example, volume reduction and fixation by melting waste. In addition, as seen in the Recycling Law, effective resource recovery, recovery of unused energy, recycling of processed materials, etc. have been promoted, and efforts for effective use of waste have been strengthened. Furthermore, there are many issues required for waste treatment, such as the control of trace contaminants such as dioxins, for the stable treatment of harmful substances.

Under these circumstances, waste is introduced into a fluidized bed to generate pyrolysis gas, the pyrolysis gas is burned at high temperature to decompose trace contaminants, and the heat of combustion is used to generate external energy. Attention has been focused on a process for melting incineration residues without using methane.

[0004] The term "pyrolysis" as used herein refers to an operation of heating waste to a high temperature in an oxygen-free or low-concentration oxygen atmosphere, and in a so-called fluidized bed incinerator in which sludge or the like is burned at 750 to 1000 ° C. Unlike the exothermic reaction, the upper limit of the heating temperature is limited to approximately 650 ° C. to perform the thermal decomposition reaction.

[0005] Generally, when thermal decomposition of organic waste is carried out, a combustible gas containing hydrogen, carbon monoxide, hydrocarbons, etc., char and ash are produced. The advantages of performing pyrolysis in this way are (a) recoverable fuel that can be stored and transported, and (b) relatively slow reaction,
It can absorb fluctuations in waste quality and supply amount of waste, (c) The amount of NOx generated is relatively low due to relatively low temperature, and (d) the amount of generated gas is significantly smaller than the amount of incineration exhaust gas. Small size, (e) Valuable metals can be recovered in an unoxidized state without melting by low-temperature pyrolysis.
F) Dry distillation or partial combustion in the pyrolysis furnace can increase the load of waste input into the pyrolysis furnace.

[0006] When the melting process is combined with the above-mentioned thermal decomposition, the following advantages are obtained. In other words, (g) the ash can be melted using the energy of the waste, and (h) the combustion air to be introduced into the melting furnace is low in air ratio. The equipment can be made more compact, and (iii) the amount of trace harmful substances such as dioxins generated by high-temperature combustion in a melting furnace can be reduced. In a fluidized bed pyrolysis-melting process using a fluidized bed for pyrolysis, waste is put into a fluidized bed of a fluidized bed pyrolysis furnace and gasified in a process of circulating in the fluidized bed with a fluidized medium such as sand. . At this time, the amount of air supplied to the pyrolysis furnace is 30 to 40% of the theoretical air amount so that the generated gas contains a large amount of combustibles.
And the fluidized bed temperature is 450 to 650 ° C. That is, the fluidized bed temperature is set to a range not lower than the lower limit temperature necessary for obtaining good thermal decomposition and not higher than the upper limit temperature at which aluminum as a valuable metal can be recovered without being melted and oxidized.

[0007] The combustible gas, char, and ash generated in the pyrolysis furnace are subsequently introduced into a subsequent melting combustion furnace,
High-temperature combustion is performed at a low air ratio of about 1.3, whereby ash is melted. That is, by combining a fluidized bed pyrolysis furnace and a melting combustion furnace,
A method of treating waste without using external energy is realized. Exhaust gas sent from the melting and burning furnace is recovered by a waste heat boiler and an air preheater, and then discharged to the atmosphere via an exhaust gas treatment device.

[0008]

The fluidized bed pyrolysis furnace described above has a structure in which a fluidizing gas containing oxygen is blown from the bottom of the cracking furnace, and the oxygen concentration is highest at the bottom of the fluidized bed furnace. The metal objects descending in the fluidized bed and accumulating on the furnace bottom move along the inclined bottom surface, and the oxidation proceeds considerably before reaching the incombustible material outlet. Such oxidized metal material has a problem that the resource value after recovery is reduced.

SUMMARY OF THE INVENTION The present invention has been made to solve the problems in a conventional fluidized bed pyrolysis furnace, and is capable of recovering a metal object while suppressing oxidation in the fluidized bed pyrolysis furnace. An object of the present invention is to provide a decomposition method, a pyrolysis furnace, and an apparatus for treating a burnable substance.

[0010]

According to the fluidized bed pyrolysis method of the present invention, a fluidized medium is charged into a furnace having a gas dispersion plate at the bottom, and gas is fed from below the gas dispersion plate to fluidize the fluidized medium. In a single-column type fluidized bed pyrolysis method of supplying burnable substances to a fluidized bed in a fluidized state and pyrolyzing and gasifying, a gas with no oxygen or low oxygen concentration is sent from the bottom of the fluidized bed. The point is that air or an oxygen-containing gas is blown into a fluidized bed separated from the bottom by a predetermined distance upward.

In a first embodiment of a fluidized bed pyrolysis furnace according to the present invention, a fluid medium is filled in a furnace having a gas dispersion plate at the bottom, and gas is sent from below the gas dispersion plate to fluidize the fluid medium. In a single-column fluidized-bed pyrolysis furnace that supplies burnables to a fluidized fluidized bed and pyrolyzes and gasifies, fluidizes by sending oxygen-free or low-oxygen-concentration gas from below the gas dispersion plate. The gist of the present invention is to provide a gas blowing means and a pyrolysis gas blowing means for arranging a gas blowing pipe in a fluidized bed separated from the bottom by a predetermined distance upward and blowing air or oxygen-containing gas.

In a second embodiment of the fluidized bed pyrolysis furnace according to the present invention, a fluid medium is charged into a furnace having a gas dispersion plate at the bottom, and gas is sent from below the gas dispersion plate to fluidize the fluid medium. In a single-column type fluidized bed pyrolysis furnace that supplies a substance to be burned to a fluidized bed in a fluidized state and pyrolyzes and gasifies, so that a recess is formed in a central portion of a bottom portion, an outer peripheral side and It has a gas distribution plate part divided on the inner peripheral side,
A gas dispersion plate in which the outer gas dispersion plate portion is formed at a position higher than the inner gas dispersion plate portion, and a flow in which a gas having no oxygen or low oxygen concentration is sent to the inner gas dispersion plate portion as a fluidizing gas. The gist of the present invention is to include a gasification means blowing means and a pyrolysis gas blowing means for sending air or an oxygen-containing gas as a pyrolysis gas to an outer gas dispersion plate.

In the present invention, the low oxygen concentration means
Means a gas containing 5% by weight or less of oxygen, and specifically,
Exhaust gas and the like sent from the combustion furnace are shown. Further, the oxygen-containing gas means a gas containing 20% by weight or more of oxygen, specifically, air.

[0014] The burned matter processing apparatus of the present invention performs high temperature combustion by receiving a fluidized bed pyrolysis furnace of the first or second embodiment and a supply of a pyrolysis gas sent from the pyrolysis furnace. The gist of the present invention includes a melting and burning furnace for melting ash in the pyrolysis gas.

According to the fluidized bed pyrolysis method of the present invention, a gas having no oxygen or low oxygen concentration is fed from the bottom of the fluidized bed, and air or oxygen-containing gas is introduced into the fluidized bed separated from the bottom by a predetermined distance. Is blown.

According to the fluidized-bed pyrolysis furnace of the present invention, pyrolysis proceeds due to partial combustion of waste in a region above the blowing pipe, while oxygen-free or air-free air flows from the gas distribution plate in a region below the blowing pipe. Since a gas having a lower oxygen concentration is blown and the temperature is lower than that of the upper pyrolysis region, the oxidation of the metal substance that has dropped to the bottom of the fluidized bed is suppressed.

The point that the oxidation of iron decreases as the temperature decreases in a high-temperature atmosphere and that the oxidation rate decreases as the oxygen concentration decreases are described in, for example, the Third Edition Steel Handbook.
These are shown in Figures 9.94 and 9.105 in the section "9.2.3 Behavior of iron-based alloys in various environments" in I Fundamentals (edited by the Iron and Steel Institute of Japan). FIG. 9.105 shows the effect of the amounts of SO ₂ , CO ₂ , and O ₂ on the oxidation of carbon steel in a neutral atmosphere, and also shows the effects other than oxygen. _Two concentration dashed line graphs can be referenced. This is because the SO ₂ concentration in the exhaust gas is 0.01% or less in the combustion of general municipal waste, and the effect of SO ₂ can be ignored.

According to the apparatus for treating burnable matter of the present invention, air or an oxygen-containing gas is introduced only for an amount required for pyrolysis gasification. The composition is stabilized, so that the combustion in the combustion furnace supplied with the pyrolysis gas is stabilized.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows an overall configuration of a fluidized bed pyrolysis furnace used in a fluidized bed pyrolysis method of the present invention and a waste treatment facility to which a burnable material treatment apparatus is applied. is there. The waste treatment equipment shown in the figure includes a dust feeder 10, a fluidized bed pyrolysis furnace 11, a melting furnace 12 as a melting and burning furnace, a heat exchanger 13, a waste heat boiler 14, and a gas cooling chamber 15 in that order from the upstream side. , A bag filter 16, and an exhaust fan (induction blower) 17, and the waste picked up by the waste crane 8 from the waste pit 7 is supplied to the hopper of the dust collector 10. ing. The refuse crane 8 is operated by an operator in the crane operation room 9.

A non-combustible discharge device 18 having a screw feeder 18a is provided below the fluidized bed pyrolysis furnace 11. The non-combustible discharge device 18 is separated by a separation device and a magnetic separation device (not shown) attached to the non-combustible discharge device 18. Impurities, non-ferrous metals, and iron are recycled and used,
The sand is returned to the fluidized bed of the fluidized bed pyrolysis furnace 11.

A slag discharge device 19 containing a conveyor 19a is provided below the melting furnace 12, and a water sealing tank 20 containing a screw conveyor 20a for collecting molten slag is provided below the slag discharge device 19. Is provided. The molten slag obtained from the slag water sealing tank 20 is also recycled.

The molten fly ash recovered from the waste heat boiler 14 and the bottom of the gas cooling chamber 15 is supplied to a molten fly ash heavy metal recovery device 25, and the recovered heavy metals such as Cu, Pb, Zn, etc. To be recycled for refining. In addition, the molten fly ash heavy metal recovery device 25
The wastewater separated from the wastewater is recycled through a wastewater treatment facility 26 and a salt recovery facility 27.

Further, harmful components such as dioxin contained in the exhaust gas from the bag filter 16 are sent to the heater 21 by the exhaust fan 17, heated to satisfy the reaction conditions, and then supplied to the catalytic reaction tower 22. After the harmful components are removed, they are released from the chimney 23 into the atmosphere. The exhaust gas sent from the bag filter 16 is branched and provided to the circulation fan 24, and the exhaust gas sent from the circulation fan 24 is returned to the fluidizing gas inlet 11 a of the fluidized bed pyrolysis furnace 11. Exhaust gas sent out from the heat exchanger 13 is also returned to the fluidizing gas inlet 11a.

The heat recovered by the waste heat boiler 14 is used for power generation and is consumed by the owner or sold. Reference numeral 28 denotes a fan for introducing the intake air from the dust pit into the exhaust gas system.

Next, the configuration of the main part of the waste treatment facility will be described in detail. FIG. 2 shows a first embodiment of a fluidized bed pyrolysis furnace according to the present invention. FIG. 2 (a) is a plan view of a main part showing an arrangement of a blowing pipe (described later). (b) is a longitudinal sectional view of the fluidized bed pyrolysis furnace.

In FIG. 2, a single column fluidized bed pyrolysis furnace 1 is used.
1 is provided with a dispersion plate 112 having a number of gas injection holes 111 at the bottom thereof, and a wind box 113 below the dispersion plate 112. Fluidizing gas is introduced into the wind box 113 from the fluidizing gas inlet 11a. Therefore, when the fluidizing gas is injected upward from the wind box 113 through the gas injection holes 111 of the dispersion plate 112, the sand particles S filled on the dispersion plate 112 are fluidized, and the fluidized sand particle layer, The fluidized bed FD is formed. As the fluidizing gas, circulating exhaust gas having no oxygen or low oxygen concentration is used, and the fluidizing gas is set to a minimum mass velocity at which the sand particles can be fluidized, that is, a fluidization starting velocity. A configuration in which the circulating exhaust gas is injected from the gas dispersion plate 112 is described in claim 2.
Can be considered as a fluidizing gas injection means.

A waste inlet 114 and a main burner 115 for starting are provided above the fluidized bed FD in the fluidized bed pyrolysis furnace 11, and a free board portion 11b is provided above the fluidized bed FD. Is formed.

Gas dispersion plate 1 in fluidized bed pyrolysis furnace 11
Above 12, there is provided a blowing pipe 116 for introducing air or oxygen-containing gas for performing pyrolysis gasification by partial combustion. The blowing pipe 116 is composed of a plurality of parallel pipes that traverse the inside of the fluidized bed pyrolysis furnace 11.
Both ends are supported by the furnace wall of the fluidized bed pyrolysis furnace 11 (see FIG. 2A). The blowing pipe 116 can be regarded as a means for blowing pyrolysis gas.

Each of the blowing pipes 116 is branched from the collecting pipe 116a so that the pyrolysis gas can be dispersed and injected into the fluidized bed pyrolysis furnace 11. On the lower surface side of each blow pipe 116, a pair of spray holes are formed in the blow pipe sectional direction, and the blow holes are
6 are provided at a predetermined pitch along the axial direction. The flow of the gas injected from the injection holes flows downward once, but changes its direction upward along with the fluidizing gas flowing upward in the fluidized bed FD. In consideration of such a gas flow, the blowing pipe 116 and the gas distribution plate 1
The distance l from the upper surface of the substrate 12 should be at least 100 mm. In such a configuration, a region above the blowing pipe 116 in the fluidized bed FD is a pyrolysis region.

An incombustible extraction passage 118 is provided vertically through the center of the gas dispersion plate 112, and an incombustible discharge device 18 is disposed at the lower end thereof. The incombustible discharge device 18 is provided with a screw conveyor 18a and a vibrating sieve 18b, and separates incombustibles from sand particles S conveyed by the screw conveyor 18a. The sand particles S from which incombustible substances have been removed by the incombustible substance discharge device 18 are returned to the fluidized bed FD by a conveyor (not shown).

The melting furnace 12 utilizes the supplied combustion air and auxiliary fuel to produce the fluidized bed pyrolysis furnace 11.
Is further burned, and the heat generated by this combustion is used to melt the ash in the gas and discharge it as slag. The inner wall of the melting furnace 12 is made of a refractory material, and a combustion chamber 12a and a slag separation part 12b are formed in the furnace in order from the top. Are provided respectively. Above the combustion chamber 12a, a fluidized bed pyrolysis furnace 11 is provided.
A pipe 12e led from an outlet 11g of the air injection nozzle 12g is connected, and a plurality of air injection nozzles 12 are provided below the pipe 12e.
f is provided. These air injection nozzles 12f inject air into the melting furnace 12 from a direction close to the tangential direction of the furnace wall having a circular cross section, thereby forming the combustion chamber 12a.
A swirl flow can be formed in the inside.
A starting burner 12g is provided above the pipe 12e, and a heating burner 12h is provided at the furnace top.

The heat exchanger 13 is provided for heating the fluidizing gas supplied to the fluidized bed pyrolysis furnace 11 by utilizing the heat of the high temperature combustion gas sent from the melting furnace 12. .

The waste heat boiler 14 has a heat exchanger 1
The steam generated by the boiler 14 is converted into electric energy by a generator 29, and is used as surplus power or equipment power. Collected.

FIG. 3 shows a supply path of the circulating exhaust gas and the pyrolysis gas introduced into the fluidized bed pyrolysis furnace 11. In the figure, the exhaust gas discharged from the melting furnace 12 is used as the circulating exhaust gas supplied to the fluidizing gas injection port 11a. On the other hand, as the pyrolysis gas supplied to the blowing pipe 116, air sent by a blower is used. In addition, the exhaust gas sent out through the boiler 14 and the temperature-reducing scrubbers 40 and 41 is converted into an exhaust fan 4.
2. Those returned by the damper 43 and the recirculation blower 44 are also included.

Next, the processing operation of the waste disposal equipment having the above configuration will be described with reference to FIG. First, FIG.
In a), the circulating exhaust gas is supplied from the fluidizing gas inlet 11a into the wind box 113, and the gas is injected upward from the wind box 113 through the gas injection port 111 of the dispersion plate 112 at the fluidization start speed. The sand particles S filled above the dispersion plate 112 start to move, and a fluidized bed is formed. Also, about three times as much air as the circulating exhaust gas is introduced from the blowing pipe 116. In this state, the waste inlet 114
(W), such as municipal solid waste, is dropped into the fluidized bed FD, and is caught in the flowing sand particles as shown in FIG. Pyrolysis takes place.

The metal material in the waste material descends in the thermal decomposition zone in the fluidized bed FD, and during this descent, the combustible material accompanying the metal material is thermally decomposed. Next, the metals that have passed through the blowing pipe 116 come into contact with only the exhaust gas containing almost no oxygen, which is blown up from the gas dispersion plate 112. Therefore, oxidation of the metals does not proceed in the region below the blowing pipe 116.

In FIG. 3C, metals descending in the fluidized bed FD are deposited on the gas dispersion plate 112 as the bottom of the fluidized bed.

The metals deposited on the gas dispersion plate 112 gradually move toward the center of the fluidized bed pyrolysis furnace along the inclination of the gas dispersion plate 112, as shown in FIG.
After dropping into the incombustible discharge outlet 117, the incombustible discharge passage 11
Collected from 8. At this time, in the structure of the conventional fluidized bed pyrolysis furnace, oxidation progressed while the metal material reached the noncombustible material discharge port 117 (generally, about 30 minutes to 1 hour), and the resource value was reduced. In the fluidized bed pyrolysis furnace according to the present invention, oxidation of metals does not proceed in a region below the blowing pipe 116, so that valuable metal materials can be effectively recovered.

When the thermal decomposition in the fluidized bed FD is performed only by the pyrolysis gas introduced from the blowing pipe 116, in other words, the influence of the temperature increase due to the oxygen in the fluidization gas is eliminated. And the pyrolysis gas generated by the pyrolysis has a stable composition, and the fluidized bed F
Ascending from D, the outlet 11 at the upper end of the free board portion 11b
g. The pyrolysis gas sent out in this manner is then sent to the melting furnace 12 where it is further burned, the ash in the pyrolysis gas is melted, and discharged as slag from the slag discharge port 12c.
Sent to At this time, the combustion of the melting furnace 12 supplied with the pyrolysis gas having a stable composition is stabilized.
The high-temperature gas after combustion is introduced into the high-temperature gas inlet of the heat exchanger 13 through the heat-resistant pipe 12i.

A part of the sand particles S constituting the fluidized bed FD in the pyrolysis furnace 11 is guided to the incombustible discharge passage 118 together with the incombustible mixed therein and sent to the incombustible discharge device 18. . In the incombustible discharge device 18, the mixture is sieved to separate coarse incombustibles and fine sand particles S. The coarse incombustibles contain valuable metals such as unmelted aluminum and iron, and these valuable metals are extracted as resources for recycling. The sand particles S from which incombustible substances have been removed are returned to the fluidized bed FD of the pyrolysis furnace 11.

On the other hand, the gas cooled by the heat exchanger 13 is sent out from the low-temperature side gas outlet, and is discharged from the chimney 23 through the waste heat boiler 14 and the bag filter 16 to the outside of the waste treatment facility. That is, after the temperature of the exhaust gas sent from the melting furnace 12 is sufficiently lowered, the exhaust gas is passed through the waste heat boiler 14 and the bag filter 16 to prevent the waste heat boiler 14 and the bag filter 16 from being thermally damaged. can do.

FIG. 5 shows a modified example of the above-described blowing pipe 116. In the blowpipe 50 shown in FIG. 3A, the gas blowing sections 50a are arranged at equal intervals on the outer peripheral surface of the fluidized bed pyrolysis furnace 11, and the nozzle sections 50b are arranged facing the center of the furnace. It is.

In the blowing pipe 51 shown in FIG. 3B, the gas blowing portions 51a are arranged at equal intervals on the outer peripheral surface of the fluidized bed pyrolysis furnace 11, and the nozzle portions 51b are directed toward the center of the furnace. In addition to the arrangement, the tip of each nozzle portion 51b is
c.

FIG. 6 shows a fluidized bed pyrolysis furnace according to a second embodiment of the present invention. In the configuration shown in the figure, the wind box is divided into an outer circumferential wind box (referred to as a first wind box) 60 and an inner circumferential wind box (referred to as a second wind box) 61. The air or oxygen-containing gas is used as a pyrolysis gas in the first wind box 60.
The oxygen-free or low-oxygen-concentration gas is introduced into the second wind box 61 as a fluidizing gas.
Also, the gas distribution plate is divided for each wind box,
The gas distribution plate (inner peripheral gas distribution plate portion) 112b corresponding to the second wind box 61 is formed at a position lower than the gas distribution plate (outer peripheral gas distribution plate portion) 112a corresponding to the first wind box 60. ing. The configuration in which the pyrolysis gas is introduced from the first wind box 60 can be regarded as the pyrolysis gas blowing means of claim 3, and the configuration in which the fluidizing gas is introduced from the second wind box 61 is claim 3. Can be considered as a fluidizing gas injection means.

Therefore, the region depressed from the periphery of the gas dispersion plate 112a becomes an oxygen-free region or a region where almost no oxygen is present, and the oxidation of the metal material descending in the fluidized bed FD is suppressed.

According to this configuration, the noncombustible material discharge passage 118
There is an advantage that the oxidation of the metal deposited on the gas dispersion plate 112b does not progress even if the extraction speed for extracting the incombustibles from the gas is low.

[0047]

As is apparent from the above description,
According to the fluidized bed pyrolysis method and the fluidized bed pyrolysis furnace of the present invention, metals such as iron and aluminum mainly having a particle size larger than sand particles descend in the fluidized bed and reach the bottom of the fluidized bed. Stagnates on the bottom of the fluidized bed until it is collected from the impurity extraction passage, but at the bottom of the fluidized bed, there is little or no oxygen, and the temperature is lower than that of the pyrolysis zone. The oxidation of the substance does not proceed.
Therefore, metal objects can be collected in a state of high resource value.

Further, the pyrolysis gas and the fluidizing gas are supplied independently to the fluidized bed pyrolysis furnace, and air or an oxygen-containing gas is introduced only in an amount required for pyrolysis gasification. The temperature is stabilized, and the composition of the pyrolysis gas generated in the fluidized bed pyrolysis furnace is stabilized. Thereby, there is an advantage that the operating state of the combustion furnace at the subsequent stage of the fluidized bed pyrolysis furnace is stabilized.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing the overall configuration of a waste treatment facility to which the present invention is applied.

FIG. 2 is an explanatory view showing a first embodiment of a fluidized bed pyrolysis furnace according to the present invention.

FIG. 3 is a block diagram showing a supply path of a fluidizing gas supplied to a fluidized bed pyrolysis furnace.

FIG. 4 is an explanatory diagram showing behavior of metals in a fluidized bed.

FIG. 5 is a plan view showing a modification of the gas injection pipe according to the present invention.

FIG. 6 is an explanatory view of a main part showing a second embodiment of the fluidized bed pyrolysis furnace according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Fluidized bed pyrolysis furnace 11a Fluidized gas inlet 11b Free board part 12 Melting furnace 13 Heat exchanger 14 Waste heat boiler 18 Impurity discharge device 116 Blowing tube FD Fluidized bed

Claims (5)

[Claims] 1. A fluidized medium is charged into a furnace having a gas dispersion plate at the bottom, and a gas is sent from below the gas dispersion plate to fluidize the fluidized medium, thereby covering the fluidized bed in a fluidized state. In a single-column fluidized-bed pyrolysis method of supplying a combustion product and pyrolyzing and gasifying, a gas having an oxygen-free or low-oxygen concentration is sent from the bottom of the fluidized bed, and the fluid is separated from the bottom by a predetermined distance upward. A fluidized bed pyrolysis method, characterized by blowing air or an oxygen-containing gas into the bed. 2. A fluidized medium is charged into a furnace having a gas dispersion plate at the bottom, and a gas is sent from below the gas dispersion plate to fluidize the fluidized medium, thereby covering the fluidized bed in a fluidized state. In a single-column fluidized bed pyrolysis furnace for supplying a combustion product and pyrolyzing and gasifying, a fluidized gas blowing means for feeding oxygen-free or low-oxygen gas from below the gas dispersion plate, and a predetermined distance from the bottom A fluidized bed pyrolysis furnace, comprising: a pyrolysis gas blowing means for arranging a gas blowing pipe in the fluidized bed separated upward and blowing air or oxygen-containing gas. 3. A fluidized medium is charged into a furnace provided with a gas dispersion plate at the bottom, and a gas is sent from below the gas dispersion plate to fluidize the fluidized medium, thereby covering the fluidized bed in a fluidized state. In a single-column fluidized bed pyrolysis furnace that supplies a combustion product and pyrolyzes and gasifies, the gas dispersion divided into an outer peripheral side and an inner peripheral side so that a recess is formed in a central portion of the bottom. It has a plate part,
A gas dispersion plate in which the outer peripheral side gas dispersion plate portion is formed at a position higher than the inner peripheral side gas dispersion plate portion, and a gas having no oxygen or low oxygen concentration as a fluidizing gas; A fluidized-bed pyrolysis furnace comprising: a fluidized gas blowing means for feeding a gas to the outer peripheral side; and a pyrolysis gas blowing means for feeding air or an oxygen-containing gas as a pyrolysis gas to the outer gas dispersion plate portion. 4. The fluidized bed pyrolysis furnace according to claim 2, wherein the fluidizing gas utilizes exhaust gas sent from a combustion furnace. 5. The fluidized-bed pyrolysis furnace according to claim 2, wherein high-temperature combustion is performed by receiving a supply of a pyrolysis gas sent from the pyrolysis furnace. An apparatus for treating an object to be burned, comprising: a melting and burning furnace for melting ash.