KR100482887B1 - Fluidized Bed Gasification and Melting Combustion Method and Apparatus - Google Patents

Abstract

The present invention provides a combustion method and apparatus in which a combustible material, such as waste, coal, etc., is vaporized to produce a combustible gas containing a sufficient amount of combustible components to melt ash with its own heat. The fluidized bed furnace 2 has a substantially circular cross-sectional shape. The moving bed 9 in which the fluid medium stays and diffuses is formed in the center of the furnace, and the fluidized bed 10 in which the fluid medium is actively flowing is formed in the periphery of the furnace. The fluidized medium is directed from the top of the fluidized bed 10 to the top of the moving bed 9, circulating two layers. The combustible material 11 is injected into the upper portion of the moving bed 9 and vaporized while circulating with the fluidized medium to form combustible gas. The amount of oxygen supplied to the fluidized bed furnace 2 is set equal to that contained in the amount of air of 30% or less of the theoretical amount of combustion air. The temperature of the fluidized bed 10 is maintained at 450 ° C. to 650 ° C. such that the resulting combustible gas contains a large amount of combustible components. The combustible gas and the fine particles generated in the fluidized bed furnace 2 are supplied to a molten combustion furnace which is burned at a high temperature, and the resulting ash is melted.

Description

Fluidized Bed Vaporization and Melt Combustion Method and Apparatus

The present invention relates to a method and apparatus for vaporizing a combustible material in a fluidized bed furnace to burn the resulting combustible gas and fine particles at a high temperature in a molten combustion furnace, thereby melting ash.

In recent years, it is required to reduce the volume of waste generated in large quantities, for example, municipal waste, waste plastic, etc. by incineration, and to effectively use heat obtained from incineration. Ashes generated from incineration of waste materials generally contain harmful heavy metals, so in order to treat ashes burned by landfill, certain measures must be taken, for example, solidification of heavy metals. Patent publication JP-B2-62-35004 provides a method and apparatus for burning a solid material. In this combustion method, the solid material is thermally decomposed in a fluidized bed pyrolysis furnace, and pyrolysis products, ie combustible gases and particles, are introduced into the cyclone furnace, where the combustible components are burned to high intensity by pressurized air and ash is swung Due to the collision with the wall surface is melted. The molten ash flows down the wall and the resulting molten slag solidifies away from the outlet into the moisture chamber.

However, this method has a problem in that a large amount of unreacted combustible components in the combustible gas generated in the furnace are transported out of the furnace because the entire fluidized bed is in a state of actively flowing. Therefore, high vaporization rate cannot be obtained. In addition, vaporization materials usable in fluidized bed furnaces have been, until now, small coals having particle diameters ranging from 0.5 mm to 3 mm, and waste materials finely ground to several millimeters in size. Larger vapors will interfere with flow, and smaller vapors will be transported to the outside of the furnace along with the combustible gases as unreacted combustibles without being fully vaporized. Therefore, in the conventional fluidized bed furnace, it is necessary to grind the vaporized material in advance by using a grinder or the like to make particles of uniform size as a pretreatment performed before the vaporized material is transferred into the furnace. Thereby, vaporization materials which do not fall within the prescribed particle diameter range cannot be used, and the production rate must be sacrificed to some extent.

In order to solve the aforementioned problem, Japanese Patent Application Publication No. JP-A-2-147692 provides a fluidized-bed gasification method and a fluidized-bed gasification furnace. In this fluidized bed vaporization method, the furnace has a rectangular cross-sectional shape, and the mass velocity of the fluidized gas injected upward from the center of the furnace bottom portion into the furnace is set lower than the mass velocity of the fluidized gas supplied from the two side ends of the furnace bottom portion. The upstream of the fluidizing gas is directed from the top of each side end of the furnace bottom to the center of the furnace. Thereby, the moving bed in which the fluid medium stays is formed in the center of the furnace, and the fluidized bed in which the fluid medium is actively flowing is formed in each side end of the furnace. Combustibles are fed to the moving bed. Fluidized gas is a mixture of air and steam, or a mixture of oxygen and steam, and the fluidized medium is silicate sand.

However, this method has the following problems:

(1) Vaporization and combustion reactions occur simultaneously in all moving and fluidized beds. Thus, volatiles that easily evaporate are vaporized and burned at the same time, while being transported as unreacted materials together with the combustible gases produced in the fixed carbon char and tar furnaces which are difficult to vaporize. Thereby, a high vaporization rate cannot be obtained.

(2) Where flammable gas from the furnace is combusted for use in steam and gas turbine combined cycle power plants, the fluidized bed furnace is to be pressurized. In this case, however, since the furnace has a rectangular cross-sectional configuration, it is difficult to manufacture the furnace in the form of a pressurized furnace. The preferred vaporization pressure is determined by the field of use of the produced combustible gas. If the gas is used as a conventional gas for combustion, the furnace pressure will be on the order of several thousand mmAq. However, if the produced combustible gas is used as fuel for the gas turbine, the furnace pressure should be as high as several kgf / cm 2. When the gas is used as fuel for high vaporization combined cycle power generation, it is suitable to use a furnace pressure higher than about 10 kgf / cm 2.

In the treatment of wastes such as municipal waste, capacity reduction by burning combustible waste still plays an important role. With regard to incineration, in recent years, there is an increasing demand for environmentally friendly waste treatment technologies such as dioxin control measures, harmless smoke dust production techniques, and improved energy recovery rates. In Japan, the municipal waste incineration rate is about 100,000 tons / day, and the energy recovered from the total urban waste is about 4% of the electrical energy consumed in Japan. In recent years, urban waste energy utilization is low at about 10%. However, if the energy utilization rate is improved, the consumption rate of fossil fuels will be correspondingly reduced, contributing to the prevention of global warming.

However, current incineration systems involve the following problems:

i) Power generation rate cannot be improved due to corrosion problem by HCl.

Ii) The environmental pollution prevention device controlling HCl, NO _x , SO _x , mercury, dioxin, etc. becomes complicated, resulting in increased cost and equipment area.

V) Due to strict regulations and the difficulty of securing site for post-treatment, there is an increasing tendency to install a device for melting burned ash.

IV) There is a need for expensive equipment to remove dioxins.

V) Difficult to recover valuable metals.

The object of the present invention is to solve the problems of the related art, and to contain a large amount of combustible components from combustible materials such as waste, for example municipal waste, waste plastics, or coal. It is to produce highly efficient combustible gas.

Another object of the present invention is to provide a method and apparatus for combustible material vaporization, which is suitable for energy regeneration and can easily generate high pressure combustible gas.

It is still another object of the present invention to provide a gasification and melt combustion method and apparatus capable of producing combustible gas containing a large amount of combustible components and melting the combusted ash by the heat of the produced combustible gas.

Another object of the present invention is to provide a homogeneous combustible gas containing char and tar having a sufficiently high exothermic value and to generate a high temperature of 1,300 ° C. or more by its own heat.

Another object of the present invention is to provide a vaporization apparatus in which a non-combustible substance is discharged smoothly without any problem.

Another object of the present invention is to provide a vaporization method and apparatus for allowing valuable metals contained in waste material to be regenerated from a fluidized bed furnace having a reduced atmosphere without being oxidized.

The present invention provides a method of generating combustible gas by vaporizing combustible materials in a fluidized bed furnace. In the process of the invention, the fluidized bed furnace is configured to have a generally circular cross section. The fluidized gas supplied to the fluidized bed furnace includes a central fluidized gas supplied in an upward flow from the center of the bottom of the furnace to the inside of the furnace, and a peripheral fluidized gas supplied in an upward flow of the furnace from the periphery of the bottom of the furnace. Central fluidized gas has a lower mass velocity than ambient fluidized gas. The fluidization gas at the top of the furnace and the upward flow of the fluid medium are directed to the center of the furnace by the inclined walls, thereby forming a moving bed in which the fluid medium (usually silicate sand) stays and diffuses in the center of the furnace. And forming a fluidized bed in the periphery of the furnace in which the fluidized medium is actively flowed so that the combustibles supplied to the furnace are vaporized together with the fluidized medium from the bottom of the moving bed to the fluidized bed and from the top of the fluidized bed to the moving bed. Form flammable gas. The oxygen content of the central fluidized gas is not set higher than the ambient fluidized gas, and the temperature of the fluidized bed is maintained in the range of 450 ° C to 650 ° C.

In the present invention, the centralized gas is selected from one of three gases, namely steam, a gas mixture of steam and air, and air. The ambient fluidizing gas is selected from one of three gases: oxygen, a gas mixture of oxygen and air, and air. Therefore, as shown in Table (1), there are nine central and ambient fluidization gas combination methods. The appropriate combination can be chosen depending on whether vaporization or economic feasibility is important.

In Table (1), the first combination provides the highest vaporization rate. However, the cost is high because the amount of oxygen combustion is large. As the vaporization rate is lowered, first, the oxygen consumption amount is reduced, and secondly, the vapor consumption amount is reduced. In this case, the cost is also reduced. Oxygen that can be used in the present invention is high purity oxygen. Low purity oxygen obtained using an oxygen addition film can also be used. Combination No. 9, a combination of air and air, is known as combustion air used in conventional incinerators. In the present invention, the fluidized bed furnace has a circular cross-sectional shape, and therefore, the lower protruded area of the inclined wall provided in the upper portion of the periphery in the furnace is the lower protruded area of the inclined wall used when the fluidized bed furnace has a rectangular cross-sectional area. Greater than Therefore, the flow rate of the surrounding fluidizing gas is increased, so that the oxygen supply is increased. Therefore, the vaporization rate is improved.

Table (1)

Preferably, in the method of the present invention, the fluidizing gas further comprises an intermediate fluidizing gas which is supplied to the inside of the furnace from an intermediate portion between the center and the peripheral portion of the furnace bottom. The intermediate fluidized gas has a mass velocity that is intermediate between the mass velocity of the central fluidized gas and the mass velocity of the surrounding fluidized gas. The intermediate fluidized gas is one of three gases, two gases, a gas mixture of steam and air, and air. Thus, there are 18 combination methods of central, intermediate, and surrounding fluidized gases. The oxygen content is preferably installed so as to gradually increase from the center of the furnace to the periphery. Fifteen preferred gas combinations are made as shown in Table (2).

Table (2)

Depending on whether the importance is evaporation rate or economic feasibility, an appropriate combination can be selected from those shown in Table (2). In Table (2), the first combination provides the highest vaporization rate. However, since the oxygen consumption is large, the cost is high. As the vaporization rate decreases, firstly, the oxygen consumption decreases, and secondly, the vapor consumption decreases. In this case, the cost is also reduced. Oxygen usable in Tables (1) and (2) is high purity oxygen. Low purity oxygen obtained using an oxygen addition film can also be used.

When the size of the fluidized bed furnace is large, the intermediate fluidized gas preferably includes a plurality of fluidized gases supplied from a plurality of concentric intermediate parts provided between the center and the peripheral part of the furnace bottom part. In this case, the oxygenity of the fluidizing gas is lowest at the center of the furnace, and is preferably arranged to gradually increase toward the periphery of the furnace.

In the method of the present invention, the fluidizing gas supplied to the fluidized bed furnace contains an amount of oxygen contained in an air amount of 30% or less of the theoretical amount of combustion air required to burn combustible materials. Incombustibles are discharged from the periphery of the bottom of the furnace to the outside of the fluidized bed furnace, and the sand obtained by the fractionation is returned to the inside of the fluidized bed furnace. The combustible gases and microparticles produced in the fluidized bed furnace are combusted in molten combustion, ie in a melting furnace at high temperatures of 1,300 ° C. or higher, where the ashes are melted. Exhaust gases from the molten furnace are used to run the gas turbine. The pressure in the fluidized bed furnace is maintained at a level above atmospheric pressure, depending on its use. Combustible materials are waste and coal.

In addition, the present invention provides an apparatus for generating combustible gas by vaporizing combustible materials in a fluidized bed furnace. Fluidized bed furnaces include sidewalls having a generally circular cross-sectional shape; A fluidized gas dispersion mechanism disposed at the bottom of the furnace; A nonflammable material discharging unit disposed at an outer periphery of the fluidizing gas dispersion mechanism; A central supply device for supplying fluidized gas to the inside of the furnace from the central portion of the fluidized gas dispersion mechanism so that the fluidized gas flows vertically; A peripheral supply device for supplying fluidized gas from the periphery of the fluidized gas dispersion mechanism to the inside of the furnace to allow the fluidized gas to flow vertically; An inclined wall for directing the fluidized gas and the fluid medium flowing in a vertical direction from the top of the peripheral feeder to the center of the furnace; And a freeboard disposed on the inclined wall. The central feeder supplies fluidized gas with a relatively low mass rate and a relatively low oxygen concentration. The peripheral feeder supplies a fluidized gas having a relatively high mass rate and a relatively high oxygen concentration.

In the apparatus of the present invention, the fluidized bed furnace further provides an intermediate supply device for supplying the fluidized gas to the inside of the furnace from the annular intermediate portion provided between the center and the peripheral portion of the fluidized gas dispersion mechanism so that the fluidized gas flows vertically. Include. The intermediate feeder is a fluidized gas having a mass velocity that is the middle of the mass velocities of the fluidized gases supplied by the central and peripheral feeders, and an oxygen concentration that is the intermediate of the oxygen concentrations of the fluidized gases supplied by the central and peripheral feeders. Supply. The peripheral supply device may be formed of an annular supply box. The fluidized bed furnace further comprises a combustible inlet portion disposed on top of the fluidized bed furnace. The combustible inlet may be arranged to drop the combustible into the space above the central feeder. The fluidization gas dispersing mechanism may have a periphery lower than the center portion.

The incombustibles discharging portion may include an annular portion disposed at an outer periphery of the fluidizing gas dispersing mechanism, and a conical portion extending downward from the annular portion so as to decrease the distance from the annular shape in the downward direction. The non-combustible discharge portion includes a volume control discharge device arranged in sequence, a first swing valve for sealing, a swing blocking valve, and a second swing valve for sealing.

The apparatus of the present invention may comprise a smelting furnace, ie a melting furnace, where the combustible gases and fine particles produced in the fluidized bed furnace are burned at high temperatures and the resulting ash is melted. The molten combustion furnace supplies the cylindrical first combustion chamber having a substantially vertical axis and the combustible gas and the fine particles generated in the fluidized bed furnace to the cylindrical first combustion chamber so that the combustible gas and the fine particles are pivoted about the axis of the first combustion chamber. Combustible gas inlet is provided. The molten combustion furnace further includes a second combustion chamber communicating with the cylindrical first combustion chamber, and a discharge port provided below the second combustion chamber to discharge the molten material. Exhaust gas from the second combustion chamber into the melted combustion flows into the waste heat boiler and the air preheater to regenerate the waste heat. The exhaust gas from the second combustion chamber into the molten combustion can be used to run the gas turbine. Exhaust gas enters the dust collector, where dust is removed before it is released into the atmosphere.

In the method or apparatus of the present invention, the fluidized bed furnace has a substantially circular cross-sectional shape, so that a pressure resistant furnace structure can be formed. Thereby, the pressure in the fluidized bed furnace can be maintained at a level above atmospheric pressure, and easily increases the pressure of the combustible gas generated from the combustible material supplied into the furnace. High pressure combustible gases can be used as fuel for gas turbines or boiler-gas turbine combined cycle power plants that can be operated with high efficiency. Therefore, the use of combustible gas in such a power plant makes it possible to improve the energy regeneration efficiency from the combustible material.

In the method and apparatus of the present invention, when the purpose is to treat waste, the pressure in the fluidized bed furnace is preferably maintained at a level below atmospheric pressure, so as to prevent the leakage of odor or harmful combustion gas generated in the furnace. In this case, the furnace has a substantially circular cross-sectional shape, so that the furnace wall can withstand the pressure difference between the inside and the outside well.

In the present invention, the mass velocity of the central fluidized gas supplied to the fluidized bed furnace is set lower than the mass velocity of the surrounding fluidized gas, and the upward flow of the fluidized gas in the upper part of the furnace is directed to the center of the furnace, whereby A moving bed in which the fluid medium stays and diffuses in the center portion and a fluid medium in which the fluid medium actively flows in the periphery of the furnace are formed. Thereby, the combustible material supplied into the furnace, together with the fluidized medium, is vaporized during circulation from the top of the fluidized bed to the fluidized bed from the bottom of the moving bed to the fluidized bed to form combustible gas. First, the volatiles of combustible materials are mainly vaporized by the heat of a fluidized medium (usually sand of silicate) in a moving bed moving down from the center of the furnace. Since the oxygen content of the central fluidizing gas forming the moving bed is relatively low, the combustible gas generated in the moving bed is not actually burned, but is moved upward with the central fluidizing gas to the freeboard, thereby achieving a high heat generation value of good quality. Form flammable gas.

Combustibles that lose volatiles in the moving bed and are heated, i.e., char and tar of fixed carbon, are then circulated into the fluidized bed and combusted by contacting the fluidized bed with a relatively high oxygen content surrounding fluidized gas, which is converted into combustion gas and ash. And generates combustion heat that maintains the inside of the furnace at a temperature in the range of 450 ° C to 650 ° C. The fluidized medium is heated by combustion heat, and the heated fluidized medium is directed from the upper part of the furnace toward the center of the furnace and then moved downward in the moving bed to maintain the temperature of the moving bed at the level necessary for the volatiles to vaporize. Since the entire furnace is arranged with low oxygen, especially in the center of the furnace, it is possible to produce combustible gases containing a lot of combustible components. In addition, the metal contained in the combustible material can be recycled to the non-oxidative valuable matter from the non-combustible discharge portion.

In the present invention, the combustible gas and ash produced in the fluidized bed furnace, together with other fine particles, are combustible in a molten combustion furnace. In this case, since the combustible gas contains a large amount of combustible components, the temperature in the molten combustion furnace can rise to a high level, that is, 1,300 ° C or more, and a heating fuel is unnecessary. By this, the ash can be sufficiently melted in the melting furnace. The molten ash is removed outward by molten combustion and can be easily solidified by known methods, for example, by water cooling. Therefore, the volume of ash is greatly reduced, and the harmful metal contained in the ash solidifies. Thus, the ash is changeable in recyclable form.

The above and other objects, features, and advantages of the present invention will become more apparent from the following description of the preferred embodiments with reference to the accompanying drawings in which like elements are denoted by like numerals.

Next, embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, the present invention is not limited to these embodiments. Incidentally, in Figs. 1 to 14, members denoted by the same reference numerals denote the same or corresponding members, and their overlapping description is omitted.

1 is a schematic longitudinal sectional view showing the main part of a vaporization apparatus according to the first embodiment for implementing the vaporization method of the present invention. FIG. 2 is a schematic cross sectional view of a fluidized bed furnace in the vaporization apparatus shown in FIG. Referring to FIG. 1, the vaporization apparatus is provided with a fluidized bed furnace 2. The fluidized gas is supplied into the fluidized bed furnace 2 through a fluidized gas dispersion mechanism 106 disposed at the bottom of the furnace 2. The fluidized gas is substantially flowed upstream of the furnace 2 from the central fluidized gas 7 and the periphery 3 of the furnace supplied upstream from the central portion 4 of the furnace bottom to the inside of the furnace 2. It consists of the surrounding fluidized gas (8) supplied.

As shown in FIG. 1, the central fluidizing gas 7 is one of three gases, namely, a gas mixture of steam, steam and air, and air, and the peripheral fluidizing gas 8 is three gases, namely, oxygen, oxygen and One of a gaseous mixture of air and air. The oxygen content of the central fluidizing gas 7 is set lower than the oxygen content of the surrounding fluidizing gas 8. The amount of oxygen in the total fluidized gas is set equal to the amount contained in the amount of air of 30% or less of the theoretical amount of combustion air required to burn the combustible material 11. The inside of the furnace 2 is maintained in a reducing atmosphere.

The mass velocity of the central fluidized gas (7) is set lower than the surrounding fluidized gas (8), and the upstream flow of the fluidized gas on the upper part of the furnace (2) is controlled by the action of a deflector (6). 2) to the central part. As a result, a moving bed (9) in which the fluid medium (generally, silicate sand) stays and diffuses is formed at the center of the furnace (2), and the fluidized bed (10) in which the fluid medium is actively fluidized is the fluidized bed furnace (2). Is formed in the periphery of the. The fluidized medium moves to the top of the fluidized bed 10 at the periphery of the furnace, as indicated by arrow 118. The fluidized medium then flows towards the top of the moving bed 9 by the deflector 6 and moves down in the moving bed 9. Thereafter, the fluidized medium moves along the gas dispersing mechanism 106, as indicated by arrow 112, and flows below the fluidized bed 10. In this way, the fluid medium circulates through the fluidized bed and the moving bed 10. 9, as shown by arrows 118 and 112.

The combustible material 11 is fed from the combustible material supply port 104 to the upper part of the moving layer 9. The combustibles 11 move down the moving bed 9 together with the fluidized medium, during which the combustibles 11 are heated by a heated fluidized medium, whereby most of the volatiles in the combustibles 11 Vaporize. Since there is no oxygen or only a very small amount in the moving bed 9, the product gas mainly composed of evaporated volatiles is not burned, and as shown by the arrow 116, it passes through the moving bed 9. Thus, the moving bed 9 forms a vaporization zone (G). The generated gas is then moved to the free board 102 as shown by arrow 120 and moved upwards, and discharged from the gas exhaust 108 to the combustible gas 29.

The unvaporized material in the moving bed 9, mainly char (fixed carbon) and tars, as indicated by the arrow 112, is shown in the periphery of the furnace 2 together with the fluidized medium of the moving bed 9. It moves from the bottom to the bottom of the fluidized bed 10 and is partially oxidized by the surrounding fluidized gas 8 having a relatively high oxygen content. The fluidized bed 10 forms the combustible oxidation zone S. In the fluidized bed 10, the fluidized medium is heated to a high temperature by the heat of combustion in the fluidized bed 10. The fluidized medium heated to a high temperature is moved sideways and directed to the moving bed 9, as indicated by arrow 118, by the inclined wall 6, thereby again serving as a heat source for vaporization. The temperature of the fluidized bed 10 is maintained in the range of 450 ° C. to 650 ° C. to allow the controlled combustion reaction to continue.

According to the vaporization apparatus 1 shown in FIGS. 1 and 2, the vaporization zone G and the oxidation zone S are formed in the fluidized bed furnace 2, and the fluidized medium is in two zones G and S. It acts as a heat transfer medium. Therefore, a combustible gas having a high calorific value of good quality is generated in the vaporization zone G, and char and tar 114 which are difficult to vaporize are effectively combusted in the oxidation zone S. Therefore, the flammable material vaporization rate is improved, and the combustible gas of excellent quality is produced.

As shown in FIG. 2, which is a cross-sectional view of the fluidized bed furnace 2, the moving bed 9 forming the vaporization zone G is formed in a circular shape at the center of the furnace, and the fluidized bed 10 forming the oxidation zone S is formed. ) Is formed annularly around the moving layer 9. An annular nonflammable outlet 5 is arranged around the periphery of the fluidized bed 10. By forming the vaporization apparatus 1 into a cylindrical structure, high furnace pressure can be formed easily. It is also possible to provide a pressure vessel (not shown) which is separated out of the vaporization apparatus 1 instead of the structure in which the furnace pressure is generated by the vaporization furnace itself.

3 is a schematic longitudinal sectional view of the main part of the vaporization apparatus according to the second embodiment for implementing the vaporization method of the present invention. 4 is a schematic cross sectional view of a fluidized bed furnace in the vaporization apparatus shown in FIG. In the vaporization apparatus of the second embodiment shown in FIG. 3, the fluidizing gas is supplied with the intermediate fluidizing gas 7 'supplied into the fluidized bed furnace 2 from the middle portion of the furnace bottom portion between the center portion and the peripheral portion of the furnace bottom portion, and the central fluidization gas. Gas 7, and ambient fluidizing gas 8. The mass velocity of the intermediate fluidized gas 7 ′ is selected as the middle between the mass velocities of the central and peripheral fluidized gases 7 and 8. The intermediate fluidized gas 7 'is one of three gases: steam, a mixture of steam and air, and air.

In the vaporizer shown in FIG. 3, in the same manner as in the vaporizer shown in FIG. 1, the central fluidizing gas 7 is one of three gases: vapor, a mixture of steam and air, and air. The ambient fluidizing gas 8 is one of three gases: oxygen, a mixture of oxygen and air, and air. The oxygen content of the intermediate fluidized gas 7 'is selected as the middle between the oxygen content of the central and peripheral fluidized gases 7 and 8. Thus, as shown in Table 2, 15 preferred fluid gas combinations are made. It is important for each combination that the oxygen content should increase as the distance from the center of the fluidized bed furnace 2 increases towards its periphery. The amount of oxygen in the total fluidized gas is set equal to the amount contained in the amount of air of 30% or less of the theoretical amount of combustion air required for the combustible material 11 to burn. The inside of the furnace 2 is maintained in a reducing atmosphere.

In the vaporizer shown in FIG. 3, in the same manner as in the vaporizer shown in FIG. 1, a moving bed 9 in which the fluid medium stays and diffuses is formed in the center of the furnace 2, and the flow The fluidized bed 10 in which the medium is actively flowed is formed in the periphery of the fluidized bed furnace 2. The fluidized medium circulates through the moving and fluidized beds 9, 10, as shown by arrows 118, 112. An intermediate layer 9 ′ in which the fluid medium mainly spreads in the horizontal direction is formed between the moving bed 9 and the fluidized bed 10. The moving layer 9 and the intermediate layer 9 'form a vaporization zone G, and the fluidized bed 10 forms an oxidation zone S.

The combustible material 11 delivered to the upper part of the moving bed 9 is heated while moving to the lower part of the moving bed 9 together with the fluidized medium, so that the volatiles in the combustible material 11 are vaporized. With some of the volatiles, the unvaporized char and tar in the moving bed 9 moves with the fluidized medium into the intermediate layer 9 'and the fluidized bed 10, partially vaporized and partially burned. The unvaporized material, mainly char and tar, in the intermediate layer 9 ′ moves with the fluidized medium to the fluidized bed 10 around the furnace and is burned in a surrounding fluidized gas 8 with a relatively high oxygen content. The fluidized medium is heated in the fluidized bed 10 and then circulated to a moving bed 9 which heats combustibles. The oxygen concentration in the intermediate layer 9 'is selected according to the type of combustible material (i.e. whether the volatile content is high or the char and tar content is high). That is, whether to lower the oxygen concentration mainly to carry out vaporization or to increase the oxygen concentration to mainly carry out combustion is determined according to the type of the combustible material.

As shown in FIG. 4, which is a cross-sectional view of the fluidized bed furnace 2, the moving bed 9 forming the vaporization zone is formed circularly in the center of the furnace 2, and the intermediate layer 9 ′ is the moving bed 9. Along the outer periphery of n) is formed from the intermediate fluidized gas 7 '. The fluidized bed 10 forming the oxidation zone is annularly formed around the intermediate layer 9 '. An annular nonflammable outlet 5 is arranged around the edge of the fluidized bed 10. By forming the vaporization apparatus 1 into a cylindrical structure, high furnace pressure can be formed easily. The furnace pressure is produced by the vaporizer itself or by a pressure vessel provided separately on the outside of the vaporizer.

5 is a schematic longitudinal sectional view of the vaporization apparatus according to the third embodiment of the present invention. In the vaporization apparatus 1 shown in FIG. 5, the vaporization material 11, which is a combustible material such as, for example, waste, is carried out by the double damper 12, the compression feeder 13, and the waste feeder 14. It is fed to a fluidized bed furnace. The compressed air feeder 13 compresses the vaporized material 11 into a plug-like shape, so that the pressure is sealed. Waste compressed into a plug-like shape is crushed by a grinder (not shown) and fed into the fluidized bed furnace 2 by the waste feeder 14.

In the vaporization apparatus shown in FIG. 5, the central fluidized gas 7 and the surrounding fluidized gas 8 are supplied in the same manner as in the embodiment shown in FIG. Thus, the vaporization zone and the oxidation zone of the reducing atmosphere are formed in the fluidized bed furnace 2 in the same manner as in the embodiment shown in FIG. The fluid medium acts as a heat transfer medium in both zones. In the vaporization zone, combustible gases of high heat and high calorific value are produced; Hard to vaporize char and tar are burned efficiently in the oxidation zone. As a result, a high vaporization rate and excellent quality combustible gas can be obtained. In the embodiment shown in FIG. 5, a roots blower 15 is provided to communicate the double damper 12 and the freeboard 102 in the vaporizer 1 when the waste is insufficiently compressed. The gas leaking from the furnace 2 to the double damper 12 through the compressed feeder 13 is returned to the furnace 2 by the action of the Roots blower 15. Preferably, the roots blower 15 sucks an appropriate amount of air and gas from the double damper 12 and returns it to the furnace 2 so that the upper pressure of the double damper 12 is equal to atmospheric pressure.

The vaporization apparatus shown in FIG. 5 includes a non-combustible discharge port 5, a conical chute 6, a volume control discharge device 17, a sealing first swing valve 20, and a swing blocking valve 19. , A second swing valve 20 for sealing, and a discharge device 23 equipped with a tromel, which are arranged in the following operation sequence.

(1) In the state where the sealing first swing valve 18 is opened while the second swing valve 20 is closed, and the pressure is sealed by the second swing valve 20, the volume control discharge device 17 Is operated such that the non-combustible material including sand as a fluid medium is discharged from the conical chute 16 to the swing blocking valve 19.

(2) When the swing shut-off valve 19 accommodates a predetermined amount of non-combustible material, the volume control discharge device 17 is shut off, the first swing valve 18 is closed, and the no-pressure is the first swing valve 18. Sealed by). Then, the discharge valve 22 is opened, and the pressure in the swing shutoff valve 19 is restored to atmospheric pressure. Next, the second swing valve 20 is fully open and the swing shutoff valve 19 is opened to allow the non-combustible material to be discharged to the discharge device 23.

(3) After the second swing valve 20 is completely closed, the equalizing valve 21 is opened. After the pressure in the first swing valve 18 and the conical chute 16 becomes equal to each other, the first swing valve 18 is opened, and the process returns to the first step.

These steps (1) to (3) are automatically repeated.

The discharge device 23 equipped with the trommel is continuously operated. As a result, the large incombustibles 27 are discharged to the outside of the system through the trommel, and the sand and the small incombustibles are transported by the sand circulation lifting device 24. The finely ground incombustibles 28 are removed by the classifier 25 and the sand is returned to the vaporizer 1 through the lock hopper 26. In this incombustibles discharging mechanism, the two swing valves 18 and 20 do not receive incombustibles but have only a pressure sealing function. Therefore, it is possible to prevent the incombustibles from being caught in the sealing portions of the first and second swing valves 18 and 20. If the pressure is slightly negative, no sealing is necessary.

6 is a schematic longitudinal sectional view of the vaporization apparatus according to the fourth embodiment of the present invention. In the vaporization apparatus shown in FIG. 6, the feeding and vaporizing of the vaporization material 11 and associated no-pressure sealing operation are performed by a pair of swing shutoff valves 19 and 19 ', and a pair of first and second swing valves 18. , 20), in the same manner as in the case of the mechanism for discharging the incombustibles shown in FIG. The compressed air feeder 13 used in the embodiment shown in FIG. 5 is omitted. In the embodiment shown in FIG. 6, the gas leaking from the furnace to the first swing valve 18 is returned to the furnace through a discharge valve 922 and a blower (not shown). After the first swing valve 18 is completely closed, the equalization valve 21 is opened to equalize the pressure in the swing shutoff valve 19 with the pressure in the furnace.

7 is a flowchart showing an example of a process for purifying the gas generated by the vaporizer of the present invention. In the purification process shown in FIG. 7, the vaporization apparatus 1 is supplied with the vaporization substance 11 and the fluidizing gases 7 and 8. The combustible gas produced in the vaporization apparatus 1 is sent to the waste heat boiler 31 in which heat is regenerated, and the cooled gas is sent to the cyclone separator 32 in which the solid materials 37 and 38 are separated. . Thereafter, the combustible gas is washed and cooled in the water washing tower 33, and hydrogen sulfide is removed from the combustible gas in the alkaline solution washing tower 34. The combustible gas is then stored in the gas holder 35. The unreacted char 37 in the solid material separated by the cyclone separator 32 is returned to the vaporizer 1, and the remaining solid material 38 is discharged to the outside of the system. And in the same manner as the embodiment shown in FIG. 5, the non-combustible material 27 having a large size in the non-combustible material discharged from the vaporization device 1 is discharged to the outside of the system, while the sand in the non-combustible material is discharged to the vaporization device ( Is returned as 1). Wastewater from the scrubber towers 33 and 34 enters the wastewater treatment system 36, where it is made harmless.

8 is a flowchart showing an example of a process in which the combustible gas and the fine particles generated in the vaporization apparatus 1 flow into the molten combustion furnace 41 to be burned at a high temperature, and the ash is melted. In the process shown in FIG. 8, the combustible gas 29 containing a large amount of combustible components and generated in the vaporization apparatus 1 flows into the molten combustion furnace 41. The molten combustion furnace 41 is also supplied with three gases, namely oxygen, a gas mixture of oxygen and air, and a gas 8 which is one of air, so that the combustible gas and the fine particles are burned at 1,300 ° C. or higher, and the ash is Allow it to melt. Hazardous substances, ie dioxins, PCBs, and the like are decomposed. The molten ash 44 discharged from the molten combustion furnace 41 is rapidly cooled to form slag, thereby reducing waste capacity. The combustion exhaust gas generated in the molten combustion furnace 41 is rapidly cooled in the scrubber 42 to prevent resynthesis of dioxins. The exhaust gas rapidly cooled in the scrubber 42 is sent to a dust collector, for example, a filter that removes dust 38 from the gas. The exhaust gas is then discharged from the exhaust tower 55 into the atmosphere.

9 is a schematic cutaway perspective view of a vaporization and melt combustion apparatus according to a fifth embodiment of the present invention. Referring to FIG. 9, the vaporization apparatus 1 is substantially the same as the embodiment shown in FIG. However, the gas discharge part 108 is in communication with the combustible gas inlet part 142 of the molten combustion furnace 41. The molten combustion furnace 41 includes a cylindrical first combustion chamber 140 having a substantially vertical axis and a second combustion chamber 150 inclined horizontally. The combustible gas 29 and the fine particles generated in the fluidized bed furnace 2 are supplied to the first combustion chamber 140 through the combustible gas inlet 142 to rotate about the axis of the first combustion chamber.

An upper end of the first combustion chamber 140 includes a starter burner 132 and a plurality of air nozzles 134 for supplying combustion air to rotate the air about the axis of the first combustion chamber 140. The second combustion chamber 150 is in communication with the first combustion chamber 140 at the lower end of the first combustion chamber 140. The second combustion chamber 150 includes a slag separator 160, a discharge port 152 disposed below the second combustion chamber 150 to discharge the molten material, and an exhaust port 154 disposed above the discharge port 152. do. The second combustion chamber 150 includes an auxiliary burner 136 disposed adjacent to a portion of the second combustion chamber 150 in which the second combustion chamber 150 and the first combustion chamber 140 communicate with each other, and air for supplying combustion air. It further comprises a nozzle 134. Exhaust 154 for discharging exhaust gas 46 includes a radiating plate 162 that reduces the amount of heat lost by radiation through exhaust port 154.

10 is a layout view of a fluidized bed vaporization and melt combustion apparatus according to one embodiment of the present invention used in combination with a waste heat boiler and a turbine. Referring to FIG. 1, the vaporization apparatus 1 transmits a large non-combustible substance 27 discharged from the discharge apparatus 23 together with the finely pulverized non-combustible substance 28 discharged from the classifier 25. The conveyor 172 is provided. The air jacket 185 is disposed around the conical chute 16 used to discharge the incombustibles from the bottom of the fluidized bed furnace 2. Air in the air jacket 185 is heated by hot sand drawn from the fluidized bed furnace 2. The preliminary fuel F is supplied to the first and second combustion chambers 140 and 150 of the molten combustion furnace 41. The molten material 44 discharged from the outlet 152 of the molten combustion furnace 41 is accommodated in the moisture chamber 178 where it is rapidly cooled and discharged into the slag 176.

In the arrangement shown in FIG. 10, the combustion gas discharged from the molten combustion furnace 41 is waste heat boiler 31, fuel saving device 183, air preheater 186, dust collector 43, and induction ventilation fan. It is discharged to the atmosphere through 54. The neutralizing agent (N), for example slaked lime, is added to the combustion gas generated in the air preheater 186 before the gas enters the dust collector 43. The water W is supplied to the fuel saving device 183 to be preheated, and then heated in the boiler 31 to form steam. Steam is used to power the steam turbine (ST). Air A is supplied to the air preheater 186 and heated, and then further heated in the air jacket 185. The heated air is supplied to the melting combustion furnace 41 through the air pipe 184. If necessary, heated air is also supplied to the freeboard 102.

The fine particles 180 and 190 collected at the bottom of the waste heat boiler 31, the fuel saving device 183, and the air preheater 186 are transferred to the classifier 25 by the sand circulation lifting device 24 and finely. The pulverized incombustibles 28 are removed and then returned to the fluidized bed furnace 2. The fly ash separated from the dust collector 43 contains salts of alkali metals, for example, Na and K, which are volatilized at high temperatures, and are thus treated with a chemical treatment agent in the treatment apparatus 194.

In the apparatus shown in FIG. 10, combustion in the fluidized bed furnace 2 is carried out by a low temperature partial combustion method at a low excess air ratio, and the fluidized bed temperature is maintained in the range of 450 ° C to 650 ° C, whereby a high calorific value Of flammable gas becomes possible. In addition, since combustion is performed at a low excess air ratio under a reducing atmosphere, iron and aluminum are obtained as unoxidized valuable metals. The high calorific value combustible gas and char generated in the fluidized bed furnace 2 are burned at a high temperature, that is, 1,300 ° C. or higher in the molten combustion furnace 41. As a result, ash is melted and dioxins are decomposed.

FIG. 11 shows the arrangement of a fluidized bed vaporization and melt combustion apparatus according to one embodiment of the present invention used in combination with a gas cooler 280. Referring to FIG. 11, the vaporization apparatus 1, the melting combustion furnace 41, the moisture chamber 178, the dust collector 43, the induction ventilation fan 54, and the like are the same as those in FIG. In an arrangement, a gas cooler 280 and an independent air preheater 188 are provided in place of the waste heat boiler. The hot combustion exhaust gas from the molten combustion furnace 41 is introduced into the gas cooler 280 through the high temperature duct 278 coated with a heat insulating material. In the gas cooler 280, the combustion gas is immediately cooled by the injection of fine droplets, preventing the resynthesis of dioxins. The flow rate of the exhaust gas in the high temperature duct 278 is set at a low level, that is, 5 kPa or less. The hot water generator 283 is disposed above the gas cooler 280. The air heated in the air preheater 188 is supplied to the freeboard 102 and the melting furnace 41 in the vaporization apparatus 1.

Figure 12 shows a layout of a fluidized bed vaporization and melt combustion apparatus according to one embodiment of the present invention used in conjunction with the waste heat boiler 31 and the reaction tower 310. In FIG. 12, the vaporization device 1, the melting furnace 41, the moisture chamber 178, the waste heat boiler 31, the steam turbine ST, the fuel saving device 183, the air preheater 186, the dust collector 43, the induction ventilation fan 54 and the like are similar to those in FIG. In the arrangement shown in FIG. 12, the reaction coal 310 and the superheat combustion device 320 are disposed between the waste heat boiler 31 and the fuel saving device 183. In the reaction column 310, a neutralizing agent (N), for example slaked lime slurry, is added to the combustion exhaust gas to remove HCl from the gas. The fine solid particles 312 discharged from the reaction tower 310 are sent to the classifier 25 by the sand circulation lifting device 24 together with the fine solid particles 312 discharged from the waste heat boiler 31. In the heating combustion device 320, the combustible gas and the preliminary fuel F are burned, and the steam temperature rises to about 500 ° C. In the apparatus shown in FIG. 12, the steam is at high temperature and high pressure, the excess air ratio is low, and therefore the amount of sensible heat carried by the exhaust gas is small. Therefore, the power generation efficiency is increased by about 30%.

13 is a layout view of a waste heat generation fluidized-bed gasification and melt combustion apparatus according to an embodiment of the present invention. In FIG. 13, the vaporization apparatus 1, the melting combustion furnace 41, the moisture chamber 178, the waste heat boiler 31, the dust collector 43, the induction ventilation fan 54, and the like are shown in FIG. Same as the device. Referring to FIG. 13, the reaction tower 310 is disposed between the waste heat boiler 310 and the dust collector 43. In the reaction tower 310, a neutralizing agent (N), for example slaked lime slurry, is added to the combustion exhaust gas, thereby removing HCl from the gas. The exhaust gas from the reaction tower 310 is supplied to the gas turbine assembly 420 through which the exhaust gas is used through the dust collector 43. In the gas turbine assembly 420, the air A is compressed by the compressor C, and the compressed air is supplied to the combustion device CC. In the combustion device CC, the fuel F is combusted and the resulting combustion gas acts for the turbine T together with the exhaust gas compressed in the compression device 410 and supplied to the combustion device CC. Used as a fluid. The exhaust gas from the gas turbine assembly 420 passes through the superheater 430, the fuel saving device 440, and the air preheater 450 in this order and is discharged into the atmosphere by the induction ventilation fan 54. The steam generated in the waste heat boiler 31 is heated in the superheater 430 by exhaust gas from the gas turbine assembly 420, and the heated steam is supplied to the steam turbine ST.

14 is a flow chart showing the processing of a pressurized gasification combined cycle power generation fluidized bed gasification and melt combustion method according to an embodiment of the present invention. The high temperature, high pressure combustible gas 29 produced by the pressurized vaporization furnace 1 flows into the waste heat boiler 31 'which generates steam, and the gas itself is cooled. The gas flowing out from the waste heat boiler 31 'is divided into two, one is introduced into the melting combustion furnace 41, and the other is neutralized with added neutralizer (N) to neutralize HCl and then introduced into the dust collector 43'. do. In the dust collector 43 ', the low molten material 38' in the combustible gas solidified due to the temperature drop is separated from the combustible gas and sent to the molten combustion furnace 41 in which the low molten material 38 'is melted. . The combustible gas from which the low melting material 38 'is removed is used as fuel gas in the gas turbine assembly GT. The exhaust gas from the gas turbine assembly GT undergoes heat exchange in the superheater SH and the fuel saving device Eco, and is then processed by the exhaust gas treatment device 510 and discharged into the atmosphere. The exhaust gas from the molten combustion furnace 41 passes through the heat exchanger EX and the dust collector and flows into the exhaust gas treatment device 510. The molten material 44 discharged from the molten combustion furnace 41 is rapidly cooled to form slag. The solid material 38 discharged from the dust collector 43 is treated with a chemical treatment agent in the treatment device 194.

In the treatment process shown in FIG. 14, the gas produced from the waste material is used as fuel after the removal of HCl and solid matter. Thus, the gas turbine will not be corroded by the gas. In addition, since HCl is removed from the gas, hot steam can be generated by the gas turbine exhaust gas.

Thus, the present invention provides the following useful effects;

(1) In the vaporization apparatus of the present invention, heat is diffused by the steam circulation in the fluidized bed furnace. Thus, high intensity combustion can be achieved and the size of the furnace can be reduced.

(2) In the present invention, the fluidized bed furnace can maintain combustion with a relatively small amount of air. Thus, a low excess air ratio and low temperature (450 ° C. to 650 ° C.) combustion in a fluidized bed furnace may be carried out slowly to produce a homogeneous gas containing a large amount of combustible components. Thereby, most of the combustible materials contained in the gas, tar, and char are effectively available in the next-smelting furnace 41.

(3) In the present invention, even large incombustibles can be easily discharged by the action of circulating steam in the fluidized bed furnace. In addition, iron and aluminum contained in the incombustibles are obtained as unoxidized valuable metals.

(4) The present invention provides a method and apparatus in which waste treatment is made harmless and high energy utilization is achieved.

Although the invention has been described in specific instances, it is not intended to be limited to the embodiments described, but various modifications and variations are possible without departing from the scope of the invention as defined by the appended claims.

1 is a schematic longitudinal sectional view showing the main part of a vaporization apparatus according to a first embodiment of the present invention;

FIG. 2 is a schematic cross sectional view of a fluidized bed furnace in the vaporization apparatus shown in FIG.

3 is a schematic longitudinal sectional view of a main part of a vaporization apparatus according to a second embodiment of the present invention;

4 is a schematic cross sectional view of a fluidized bed furnace in the vaporization apparatus shown in FIG.

5 is a schematic longitudinal sectional view of a vaporization apparatus according to a third embodiment of the present invention;

6 is a schematic longitudinal sectional view of the vaporization apparatus according to the fourth embodiment of the present invention;

7 is a flowchart showing an example of a process for purifying the gas generated by the vaporizer of the present invention;

8 is a flowchart showing an example of a process for melting ash;

9 is a schematic cutaway perspective view of a vaporization and melt combustion apparatus according to a fifth embodiment of the present invention,

10 is a layout view of a fluidized bed vaporization and melt combustion apparatus according to one embodiment of the present invention for use with waste heat boilers and turbines,

11 is a layout view of a fluidized bed gasification and melt combustion apparatus according to an embodiment of the present invention used with a gas cooler,

12 is a layout view of a fluidized bed vaporization and melt combustion apparatus according to an embodiment of the present invention used with the waste heat boiler and the reaction column,

13 is a layout view of a cogeneration fluidized bed vaporization and melt combustion apparatus according to an embodiment of the present invention,

14 is a flow chart showing the processing of a pressurized gasification combined cycle power generation fluidized bed gasification and melt combustion method according to an embodiment of the present invention.

※ Explanation of symbols about main part of drawing ※

1: vaporization device 2: fluidized bed furnace 3: periphery

6: deflector 7: centralized fluidized gas 8: surrounding fluidized gas

9 mobile bed 10 fluidized bed 11 flammable material

12: double damper 15: Roots blower 29: flammable gas

102: free board 104: flammable material supply port 106: fluidized gas dispersion mechanism

Claims (15)

In the method of treating a combustible material containing a nonflammable material, Providing a fluidized bed of a fluidized medium in the fluidized bed reactor by supplying an upflowing fluidized gas to the fluidized bed reactor; Whereby the upward flow of the fluidized gas to the first zone of the fluidized bed has a mass velocity greater than the upward flow of the fluidized gas to the second zone of the fluidized bed so that the fluidized medium is first in the fluidized bed as an oxidation zone. Forming a circulating flow in the fluidized bed in the fluidized bed to move upward in the zone and downward in the second zone of the fluidized bed as the vaporization zone; By supplying the combustible material to be treated above the fluidized bed, the combustible material moves downward with the fluid medium in the second region of the fluidized bed to vaporize the combustible material in the vaporization zone to generate combustible gas and char. The char is moved upwardly with the fluid medium in the first region of the fluidized bed and partially oxidized in the oxidation zone to form char particles; The non-combustible material and the fluid medium contained in the supplied combustible material are discharged from the reaction apparatus through an outlet, and the discharged fluid medium is separated from the non-combustible material and the fractionated fluid medium is returned to the fluidized bed in the reaction apparatus. Making a step; Preventing the combustible gas from being discharged through the outlet; Discharging the combustible gas and the char particles together from the reactor to introduce the discharged combustible gas and the char particles into a high temperature furnace; Burning the combustible gas and char particles at a temperature of 1300 ° C. or higher in the presbyopia to decompose harmful substances and melt ash; And And discharging the molten ash as molten slag. The method of claim 1, The combustible material treatment method characterized in that the combustible gas and char particles discharged from the reactor is introduced directly into the presbyopia without being separated by a separator. The method of claim 1, The second region of the fluidized bed is composed of a central region of the fluidized bed, the first region of the fluidized bed is a method for treating combustible material, characterized in that it consists of a peripheral region surrounding the central region. The method of claim 1, And said fluidized gas in said second zone comprises at least one gas selected from the group consisting of vapor, vapor and air gas mixtures, and air. The method of claim 1, And said fluidized gas in said first zone comprises at least one gas selected from the group consisting of oxygen, oxygen and air gas mixtures, and air. The method of claim 1, The step of discharging the incombustibles and the fluid medium through the outlet may include operating a volumetric discharge device to move the incombustibles and the fluid through a valve, and then stopping the operation of the volumetric discharge device. And then closing the valve. The method of claim 1, The combustible material treatment method of the combustible material, characterized in that consisting of waste. The method of claim 1, Preventing the combustible gas from being discharged through the outlet may include discharging the non-combustible material from the outlet through at least one valve. The method of claim 1, The fluid medium is a method for treating combustible material, characterized in that consisting of silica. The method of claim 1, Grinding of the char is a method of treating combustible material, characterized in that performed in the fluidized bed. In the method of melting and slag ash in a melting furnace after the combustible material is vaporized in a fluidized bed furnace, A portion having a small mass velocity and a portion having a large mass velocity are provided in the fluidized gas supplied to the furnace bottom of the fluidized bed furnace to form a circulating flow of a fluid medium in the fluidized bed furnace, and supply the combustible material to the fluidized bed furnace. Vaporizing gas and char, and discharging the non-combustible material and the fluidized medium included in the combustible material from the furnace bottom of the fluidized bed furnace to separate the non-combustible material and the fluidized medium, and then the fluidized medium to the fluidized bed furnace. Returning to and supplying the gas discharged from the fluidized bed furnace to the melting furnace to melt and slag the ash at 1300 ° C. or higher. The method of claim 11, Supplying the combustible material to the fluidized bed furnace, the method of treating a combustible material, characterized in that to produce gas and char by vaporizing at 450 to 650 ℃. In the method of melting and slag ash in a melting furnace after the combustible material is vaporized in a fluidized bed concentration, The fluidized bed furnace has a circular horizontal cross section, and the mass velocity of the fluidized gas supplied to the central portion of the furnace bottom of the fluidized bed furnace is lower than the mass velocity supplied to the periphery of the furnace bottom, whereby the fluidized medium descends at the center of the fluidized bed furnace, A circulating flow of the fluid medium in which the fluid medium rises at the periphery of the fluidized bed furnace is formed in the fluidized bed furnace, and the combustible material is supplied into the fluidized bed furnace and descended together with the fluidized medium to vaporize the combustible material. A vaporization zone for generating char is formed in the center of the fluidized bed furnace, and an oxidation zone, which is partially oxidized while raising the char with the fluid medium, is formed in the periphery of the fluidized bed furnace, and the nonflammable material contained in the combustibles. And discharging the fluid medium from the furnace bottom portion of the fluidized bed furnace to After classifying the fluidized medium, the fluidized medium is returned to the fluidized bed furnace, and the gas discharged from the fluidized bed furnace is supplied to the melting furnace to melt and slag ash at 1300 ° C. . In the method of melting and slag ash in a melting furnace after the combustible material is vaporized in a fluidized bed furnace, By making the mass velocity of the fluidizing gas supplied to the central portion of the furnace bottom of the fluidized bed furnace smaller than the mass velocity supplied to the periphery of the furnace bottom, a circulating flow is formed in the fluidized bed, and the flammable material is supplied to the fluidized bed furnace to supply 450 to 650 ° C. Vaporize to produce gas and char, and discharge the non-combustible material and the fluid medium contained in the combustible material from the furnace bottom portion of the fluidized bed furnace to separate the non-combustible material and the fluid medium after the fluidized medium is the fluidized bed Returning to the furnace, supplying the gas and the char discharged from the fluidized bed furnace to the turning melting furnace to melt the ash at 1300 ℃ or more and slag. In the method of melting and slag ash in a melting furnace after vaporizing municipal waste in a fluidized bed furnace, A portion having a small mass velocity and a portion having a large mass velocity are provided in the fluidized gas supplied to the furnace bottom of the fluidized bed furnace to form a circulating flow of a fluid medium in the fluidized bed furnace, and the portion having the small mass velocity and the mass velocity The fluidized gas supplied to the large portion is all air, and the combustible material is supplied to the fluidized bed furnace and vaporized at 450 to 650 ° C. to generate gas and charcoal, and the non-combustible material contained in the municipal waste and the fluid medium. After discharging from the furnace bottom of the fluidized bed furnace to separate the non-combustible material and the fluidized medium, return the fluidized medium to the fluidized bed furnace, and supply the gas and the char discharged from the fluidized bed furnace to the swivel furnace. A method of treating municipal waste, characterized in that the ash is melted and slaked at or above ℃.