JPH10306910A - Fluidized bed pyrolysis furnace and treating device for matter to be burnt - Google Patents

Abstract

PROBLEM TO BE SOLVED: To burn pyrolysis gas completely in the melting combustion furnace of a rear stage easily by a method wherein a fluidized bed type pyrolysis furnace and a treating device for matters to be burned, which prevent the generation of unburned carbon and whose combustion in a free board unit will not affect to a fluidized bed, are provided to realize the sure recovery of valuable metals through the stabilized control of the fluidized bed and restrain the generation of unburned carbon in the fluidized bed pyrolysis furnace. SOLUTION: In a single tower type fluidized bed pyrolysis furnace, fluidizing medium FD is filled into a furnace equipped with a gas dispersing plate 112 on the bottom unit thereof and gas is sent into the furnace from the lower part of the gas dispersing plate 112 to fluidize the fluidizing medium FD while matters to be burned are supplied into the fluidized bed under fluidized condition to gasify them through pyrolysis. Such a fluidized bed pyrolysis furnace is provided with shielding plates 11c, 11d for preventing the transfer of temperature in a free board unit to the fluidized bed FD.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

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

[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.

[0007] In a fluidized bed pyrolysis-melting process using a fluidized bed for pyrolysis, waste is introduced into a fluidized bed of a fluidized bed pyrolysis furnace and gas is circulated in a fluidized bed together with a fluidized medium such as sand. Be transformed into At this time, the amount of air supplied to the pyrolysis furnace is set to 30 to 40% or less of the theoretical air amount, and the fluidized bed temperature is set to 450 to 650 ° C. so that the generated gas contains a large amount of combustible components. ing. 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.

Then, the combustible gas, char, and ash generated in the pyrolysis furnace are successively 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.

[0009]

In the fluidized bed pyrolysis-melting process described above, waste is introduced into a fluidized bed of a fluidized bed pyrolysis furnace, and air is introduced into the fluidized bed to form a pyrolysis gas. While it is necessary to keep the temperature below 650 ° C,
In order to improve the combustibility in the melting and burning furnace, it is necessary to reduce the concentration of unburned carbon in the pyrolysis gas. However, in actual operation, air leaks from the waste input port, and the leaked air burns in the freeboard section of the fluidized bed pyrolysis furnace, so the temperature of the freeboard section rises and the radiant heat causes the freeboard section to form a fluidized bed. There is a problem that the temperature exceeds the set upper limit value of 650 ° C.

In order to solve such a problem, if the air ratio of the air introduced into the fluidized bed is reduced for the purpose of lowering the temperature of the fluidized bed to 650 ° C. or less, uncombusted gas is generated in the pyrolysis gas generated from the pyrolysis furnace. Therefore, a large amount of carbon is contained, and complete combustion cannot be performed in a subsequent melting combustion furnace. The carbon that has not been burned in the melting combustion furnace as described above will be mixed into the slag recovered from the bottom of the melting combustion furnace. Further, in this case, the amount of heat consumed for the unburned portion is completely wasted, and the processing efficiency is reduced.

The present invention has been made to solve the problems in such a conventional fluidized bed pyrolysis-melting process, and the temperature of the free board section does not affect the fluidized bed and the unburned carbon is not affected. It is intended to provide a fluidized bed pyrolysis furnace and an apparatus for treating an object to be burned, which suppress generation of carbon dioxide and facilitate complete combustion of the carbon in a subsequent melting furnace.

[0012]

According to a first aspect of the fluidized bed pyrolysis furnace 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. In a single-column fluidized bed pyrolysis furnace that fluidizes a fluidized medium, supplies the material to be burned to the fluidized bed in a fluidized state, and pyrolyze gasifies, a free board is placed above the fluidized bed in the furnace. The gist of the present invention is to provide a shielding plate for preventing heat from being transmitted to the fluidized bed.

[0013] In the first aspect of the present invention, the shielding plate may be formed of a plate-like member protruding at least one or more in the horizontal direction from the furnace inner wall. Can be configured. It is preferable that the beam-like member is disposed so as to face the inlet of the burnable material.

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, a fluidized bed portion and a freeboard portion in the furnace are arranged obliquely. The point is that they are connected eccentrically to each other via a connection passage.

In the second aspect of the present invention, the shield plate can be provided in a state that the shield plate protrudes in the horizontal direction from the inner wall of the free board portion on the side near the central axis of the fluidized bed portion. In the first and second aspects of the present invention, it is preferable that the freeboard portion includes a nozzle for supplying air for burning unburned carbon.

The apparatus for treating a substance to be burned according to the present invention performs high temperature combustion by receiving a fluidized bed pyrolysis furnace of the first or second embodiment and 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 furnace of the present invention, the heat generated in the freeboard portion is blocked by the shield plate or the beam-shaped member and is not transmitted to the fluidized bed. Further, according to the fluidized bed pyrolysis furnace in which the fluidized bed portion and the freeboard portion are connected eccentrically, the heat radiation from the freeboard portion does not directly reach the fluidized bed, so that the temperature of the fluidized bed is reduced. The rise can be suppressed. Therefore, since the temperature of the fluidized bed can be maintained within a predetermined range, valuable metals can be reliably recovered.

According to the apparatus for treating burnable matter of the present invention, the leaked air can be burned in the freeboard portion without affecting the temperature of the fluidized bed. The solid content in the gas, that is, the amount of unburned carbon can be reduced. Thereby, it becomes easy to completely burn the unburned carbon in the melting and burning furnace provided at the latter stage of the pyrolysis furnace.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows an entire configuration of a waste treatment facility to which a fluidized bed pyrolysis furnace and a burnable matter treatment apparatus according to the present invention are applied. The waste treatment equipment shown in FIG. 1 includes a dust feeder 10 and a fluidized bed pyrolysis furnace 1 in order from the upstream side.
1. A melting furnace 12 as a melting and burning furnace, a heat exchanger 13, a waste heat boiler 14, a gas cooling chamber 15, a bag filter 16, and an exhaust fan (induction fan) 17 are provided. On the other hand, the waste picked up by the waste crane 8 from the waste pit 7 is supplied. 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 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, and FIG. 2 (b) is a front vertical sectional view. In FIG. 2, the fluidized bed pyrolysis furnace 11 is provided with a dispersion plate 112 having a large 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, the gas injection holes 1 of the dispersion plate 112 are
When the fluidizing gas is jetted upward through 11, the sand particles S filled on the dispersion plate 112 are fluidized, and a fluidized sand particle layer, that is, a fluidized bed FD is formed. 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 formed above the fluidized bed FD.

Above the fluidized bed FD in the fluidized bed pyrolysis furnace, a pair of shielding plates 11c and 11d are formed horizontally at different heights. Each of the shielding plates 11c and 11d has a vertical cross section formed of a substantially isosceles triangle, and each of the upper and lower surfaces is formed as an inclined surface so that the pyrolysis gas does not stay. Therefore, the heat generated inside the free board portion 11b is blocked by the respective shield plates 11c and 11d in the downward direction.

In the fluidized bed pyrolysis furnace 11, the air leaking from the waste inlet 114 and secondary air are blown (described later), so that the inside of the free board portion 11b becomes a secondary combustion portion, which is mainly involved in transmitting the combustion heat. The heat radiation serving as an element does not reach the surface of the fluidized bed FD due to the presence of the shield plates 11c and 11d. On the other hand, the pyrolysis gas rising from the fluidized bed FD rises while bypassing the gap between the shielding plates 11c and 11d, and can escape to the free board portion 11b. The shielding plate 11
The reason why c and 11d are arranged at different heights is to eliminate a linear heat transmission path. In addition, the shielding plate 11
The gap d between c and 11d is preferably determined to be about 10% of the inner diameter D of the freeboard portion 11b because the heat of combustion in the freeboard is not transmitted to the fluidized bed.

The free board section 11b has a nozzle 1 for introducing secondary air for burning unburned carbon.
1e and 11f are arranged to face each other, and an outlet 11g for pyrolysis gas is provided at the top of the fluidized bed pyrolysis furnace 11.

An incombustible discharge passage 116 is provided vertically through the center of the 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).

Further, 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 is connected, and a plurality of secondary air injection nozzles 12f are provided below the pipe 12e. These secondary air injection nozzles 12f inject secondary air into the melting furnace 12 from a direction close to the tangential direction of the furnace wall having a circular cross section,
A swirling flow can be formed in the combustion chamber 12a. A starting burner 12g is provided above the pipe 12e, and a heating burner 1
2h are provided.

The heat exchanger 13 is provided to heat 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 waste heat boiler 14 is converted into electric energy by a power generator 29, and is used for surplus power and equipment required. Collected as electricity.

Next, the processing operation of the waste disposal equipment having the above configuration will be described. First, in the pyrolysis furnace 11, the fluidizing gas is supplied from the fluidizing gas
When the fluidizing gas is injected upward from the wind box 113 through the gas injection port 111 of the dispersion plate 112, the sand particles S filled above the dispersion plate 112 are violently blown up and fluidized bed Is formed. The waste (object to be treated) such as municipal waste input from the waste inlet 114 first falls onto the fluidized bed FD, is caught in the flowing sand particles, and is thermally decomposed by primary combustion.

The pyrolysis gas generated by the pyrolysis rises from the fluidized bed FD, undergoes secondary combustion in the free board portion 11b, and is sent out from the outlet 11g as the pyrolysis gas.
The pyrolysis gas generated in the fluidized bed pyrolysis furnace 11 is then sent to a melting furnace 12 where it is further burned, the ash in the pyrolysis gas is melted, and discharged as slag from a slag discharge port 12c to discharge slag. It is sent to the device 20. The high-temperature gas after combustion passes through the heat exchanger 13 through the heat-resistant pipe 12i.
Is introduced into the hot gas inlet.

On the other hand, a part of the sand particles S constituting the fluidized bed FD in the pyrolysis furnace 11 is guided to the incombustible discharge passage 116 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 in this way 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 gas outlet, and is discharged from the waste heat boiler 14 and the bag filter 16.
The waste gas is discharged from the chimney 23 to the outside of the waste treatment facility via the above-mentioned method. 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.

The state of the thermal decomposition in the pyrolysis furnace 11 depends on the temperature of the fluidized bed FD which varies according to the lower heating value of the waste supplied to the fluidized bed FD. Depends on the properties of the fluidizing gas supplied to the fluidizing gas inlet 11a. Therefore, on the assumption that the fluidizing gas is supplied stably, the fluidized bed F
The temperature of D needs to be adjusted in the range of 550 to 650 ° C. in order to perform the thermal decomposition well and to recover the aluminum in the waste. That is, if the temperature is lower than the lower limit temperature of 550 ° C., good thermal decomposition is not performed. If the temperature exceeds the upper limit temperature of 650 ° C., aluminum is melted and oxidized and scatters with the combustion gas, and is taken out through the incombustible discharge device 18. Is not possible.

According to the present invention, in order to maintain the temperature of the fluidized bed FD at 650 ° C. or lower, a shielding member is provided between the free board portion 11b and the fluidized bed FD in the fluidized bed pyrolysis furnace, or the free board portion 11b And a furnace structure capable of suppressing the transfer of heat transmitted downward from the furnace.

As described above, after the transfer of heat from the freeboard section to the fluidized bed can be prevented, the secondary combustion air is applied to the freeboard section (when the fluidizing gas is primary combustion air).
To reduce the concentration of unburned carbon. The temperature inside the free board is 7
It is desirable to set the temperature in the range of 00 to 900 ° C, but it is particularly preferable to set the temperature in the range of 760 to 800 ° C from the viewpoint of achieving both reduction of carbon and stable combustion in the furnace.

FIG. 3 shows a relationship between various reaction rates of fixed carbon of refuse and a fluidized bed temperature in the partial combustion reaction in the pyrolysis furnace 11. Graph g ₁ indicates the percentage of those exiting in the exhaust gas becomes char of fixed carbon, the ratio exiting become char as fluidized bed temperature rises to 700 ° C. from 640 ° C. decreases rapidly. Graph g ₂ shows the proportion of fixed carbon that becomes CO ₂ and goes out into the exhaust gas, and the fluidized bed temperature is 640 ° C.
From the fixed carbon as CO ₂ rises to 700 ° C.
Increase. Graph g ₃ shows H among fixed carbon.
_It indicates the rate at which it reacts with ₂ O to generate CO and H _2, and the rate increases when the fluidized bed temperature rises from 640 ° C. to 700 ° C. Graph g ₄ shows the ratio of fixed carbon that reacts with H ₂ to become CH _4, and the fluidized bed temperature changes from 640 ° C. to 7%.
The ratio of fixed carbon that reacts with H ₂ while rising to 00 ° C. is almost constant.

As described above, when the temperature of the fluidized bed is determined, the composition of the pyrolysis gas, that is, the pyrolysis reaction in the fluidized bed is substantially determined, and the combustion in the melting furnace 12 is stabilized by stabilizing the composition of the pyrolysis gas. Can be performed.
In other words, if the combustion state is not stable, the furnace pressure will fluctuate,
It also causes incomplete combustion. In general, the combustion characteristics of solid carbon and flammable gas are different from each other, but when the composition of pyrolysis gas is determined, the quantitative ratio of solid carbon and flammable gas is determined, so the combustion characteristics are also determined. Control becomes easy, and as a result, combustion can be stably performed.

When the temperature of the fluidized bed is maintained at 650 ° C. or less, since a large amount of carbon is generated, secondary air is blown into the free board portion 11b, and the temperature in the free board portion 11b is reduced to 750 to 800. If the temperature is kept at ℃, the amount of unburned carbon can be greatly reduced. Therefore,
If the unburned carbon is burned in the freeboard portion 11b by providing the shield plates 11c and 11d so as not to be affected by the heat transfer from the freeboard portion 11b, the thermal decomposition generated from the fluidized bed pyrolysis furnace 11 is performed. Solids in the gas, ie
The amount of unburned carbon can be reduced. Thus, it is easier to completely burn unburned carbon in the melting furnace 12 for the same waste treatment process, the same air ratio and the same industrial waste input. This is because the rate of solid combustion in the melting furnace 12 is reduced.

FIG. 4 shows a fluidized bed pyrolysis furnace according to a second embodiment of the present invention. FIG. 4 (a) is a plan view,
FIG. 3B shows a front vertical sectional view. In the following drawings, the same components as those in FIG. 2 are denoted by the same reference numerals, and description thereof will be omitted.

The fluidized bed pyrolysis furnace 40 shown in the figure has a waste input port 40a near the upper end of the free board section 11b.
Is provided, and waste is charged from the waste input port 40a. The shielding plate 40b as a beam-like member is provided at the waste input port 4
0a is inclined in the free board 11b so as to face the free board 11a.
b Connected to the inner wall. According to this configuration, most of the heat radiation due to combustion is blocked by the shielding plate 40b,
On the other hand, the pyrolysis gas generated from the fluidized bed FD is
0b and the free board portion 11b.
It will rise through the gaps i ₁ and i ₂ at the location.

Generally, it is extremely difficult to completely eliminate air leaking from the waste inlet 40a in view of the structure of the waste supply system. Conversely, some leakage air must be considered as one of the operating conditions. Therefore, it is necessary to take measures to prevent the secondary combustion based on the leaked air from affecting the pyrolysis gasification in the fluidized bed.

The configuration shown in FIG.
0a is arranged above the free board portion 11b, and a shielding plate 40b is arranged below the waste inlet 40a. That is, the shielding plate 40b is provided so that the leaked air is entrained in the pyrolysis gas and a secondary combustion region is formed above the free board portion 11b.

FIG. 5 shows a third embodiment of the fluidized bed pyrolysis furnace according to the present invention. The fluidized bed pyrolysis furnace 50 shown in FIG. 5 is configured such that the free board portion 11b is eccentric from the central axis of the fluidized bed FD, so that the fluidized bed F
The heat transfer to D is reduced. The free board portion 11b is eccentric so that the inner wall extension line RI on the right side of the free board portion 11b is further outside the inner wall extension line LI on the left side of the fluidized bed FD, and the free board portion 11b is connected via the connection passage 50a. And the fluidized bed section are connected. Thereby, it is configured such that heat radiation from the secondary combustion section does not directly affect the fluidized bed. In addition, a waste inlet 50b is provided above the secondary combustion section.
, And a nozzle 50c for introducing secondary air is provided on the lower side.

FIG. 6 shows a fourth embodiment in which the degree of eccentricity is smaller than that of FIG. The fluidized bed pyrolysis furnace 60 shown in FIG.
Is decentered from the central axis of the fluidized bed FD, but the free board portion is arranged such that the inner wall extension line RI on the right side of the free board portion 11b and the inner wall extension line LI on the left side of the fluidized bed FD are substantially collinear. 11b is eccentric. The free board portion 11b and the fluidized bed portion are connected via the connection passage 60a, so that heat radiation from the secondary combustion portion does not directly affect the fluidized bed. A nozzle 60 for introducing secondary air is provided below the secondary combustion section.
b and 60c are provided to face each other, and below the nozzle and above the connection passage 60a, a shielding plate 60d having the same configuration as the shielding plate shown in FIG. 2 is formed horizontally in the leftward direction. According to this configuration, the effect of heat propagation from the secondary combustion portion can be further reduced as compared with the configuration in FIG. The waste inlet 60e is provided at the right end of the connection passage 60a. Further, the waste inlet can be attached to the upper part of the furnace as in the case of FIG.

The pipe 12e connecting the fluidized bed pyrolysis furnace 11 and the melting furnace 12 is designed to have a sufficiently high flow velocity so that carbon solids do not accumulate inside the pipe 12e. However, it is inevitable that the pyrolysis gas delivered from the fluidized bed pyrolysis furnace 11 contains some unburned carbon. Therefore, it is possible to provide an auxiliary air blowing hole for air in the pipe 12e so as to blow air periodically. According to this structure, the solid unburned portion to be deposited in the pipe 12e can be burned, so that the pipe system can be eliminated from troubles such as blockage.

The auxiliary air blowing hole is not limited to the above-mentioned piping system, but may be provided at any position, for example, around the waste inlet 114. If air is blown from the vicinity of the waste inlet 114, the waste itself can be burned, and the adhesion of tar can be removed by combustion.

[0051]

As is apparent from the above description,
According to the fluidized bed pyrolysis furnace of the present invention, the combustion in the freeboard section does not affect the fluidized bed, so that the fluidized bed temperature follows only the air ratio of the fluidized gas introduced into the sand bed section. Thus, the fluidized bed can be controlled stably. Therefore, valuable metals can be reliably recovered.

Further, according to the fluidized bed pyrolysis furnace of the present invention, generation of unburned carbon can be suppressed. Therefore, in the object-to-be-burned treatment apparatus provided with the combustion furnace after the fluidized bed pyrolysis furnace, the pyrolysis gas can be completely burned in the combustion furnace without changing the air ratio in the combustion process.

[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 graph showing a relationship between a fluidized bed temperature and a reaction component.

FIG. 4 is an explanatory view showing a second embodiment of the fluidized bed pyrolysis furnace.

FIG. 5 is an explanatory view showing a third embodiment of the fluidized bed pyrolysis furnace.

FIG. 6 is an explanatory view showing a fourth embodiment of a fluidized bed pyrolysis furnace.

[Explanation of symbols]

 Reference Signs List 11 Fluidized bed pyrolysis furnace 11a Fluidized gas inlet 11b Free board part 11c, 11d Shield plate 11e, 11f Secondary air inlet 12 Melting furnace 13 Heat exchanger 14 Waste heat boiler 18 Impurity discharge device FD Fluidized bed

Continuation of the front page (51) Int.Cl. ⁶ Identification code FIF27B 15/02 B09B 3/00 302F (72) Inventor Hiroyuki Hosoda 1-3-18 Wakihamacho, Chuo-ku, Kobe Kobe Steel Kobe, Ltd. In-house (72) Inventor Mamoru Suyari 1-5-5 Takatsukadai, Nishi-ku, Kobe City Inside Kobe Steel Research Institute Kobe Research Institute (72) Inventor Tadashi Ito 1-5-5 Takatsukadai, Nishi-ku, Kobe City Stock Company Kobe Steel, Ltd.Kobe Research Institute

Claims (8)

[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 furnace for supplying a combustion product and pyrolyzing and gasifying, preventing heat of a freeboard portion from being transmitted to the fluidized bed above the fluidized bed in the furnace. A fluidized bed pyrolysis furnace comprising a shielding plate. 2. The fluidized bed pyrolysis furnace according to claim 1, wherein the shielding plate is formed of a plate-like member protruding at least one or more horizontally from the furnace inner wall. 3. The fluidized bed pyrolysis furnace according to claim 1, wherein the shielding plate is formed of a beam-like member laid on the furnace inner wall. 4. The fluidized bed pyrolysis furnace according to claim 3, wherein the beam-shaped member is disposed so as to face an inlet of the object to be burned. 5. A fluidized medium is charged into a furnace having a gas dispersion plate at the bottom, and a gas is supplied from below the gas dispersion plate to fluidize the fluidized medium, thereby covering the fluidized bed in a fluidized state. In a single-column type fluidized bed pyrolysis furnace for supplying a combustion substance and pyrolyzing and gasifying, a fluidized bed portion and a freeboard portion of the furnace are connected to each other in an eccentric state via a connection passage arranged obliquely. A fluidized bed pyrolysis furnace characterized in that: 6. The fluidized bed pyrolysis according to claim 5, wherein a shield plate is formed to protrude horizontally from the inner wall of the free board portion on the side near the center axis of the fluidized bed portion. Furnace. 7. The fluidized bed pyrolysis furnace according to claim 1, wherein a nozzle for supplying air for burning unburned carbon is provided in the free board portion. 8. A fluidized-bed pyrolysis furnace according to claim 1, wherein high-temperature combustion is performed by receiving a supply of a pyrolysis gas sent from the pyrolysis furnace, and An apparatus for treating an object to be burned, comprising: a melting and burning furnace for melting ash.