WO2005068909A1

WO2005068909A1 - Method of heat recovery, method of processing combustible material, heat recovery apparatus and apparatus for combustible material processing

Info

Publication number: WO2005068909A1
Application number: PCT/JP2004/010320
Authority: WO
Inventors: Norihisa Miyoshi
Original assignee: Ebara Corporation
Priority date: 2004-01-20
Filing date: 2004-07-20
Publication date: 2005-07-28
Also published as: EP1712839A4; EP1712839B1; EP1712839A1

Abstract

A method of heat recovery, method of processing combustible materials, heat recovery apparatus and apparatus for combustible material processing, wherein no assist fuel is needed even when the heat release value of combustible materials is low and ashes can be melted, wherein even when heat recovery is performed from combustion gas after ash melting, the adhesion of ashes to the heating surface of heat recovery apparatus can be inhibited to thereby minimize the excess ratio of heating surface, and wherein facilities such as a water spray type gas cooling system can be rendered unnecessary. In particular, a method of heat recovery comprising the step of recovering heat from first gas (G2) containing particles with large diameter in high proportion and the step of mixing the first gas (G2) after heat recovery with second gas (G1) containing particles with small diameter in high proportion and effecting heat recovery. There are further provided a method of processing combustible materials which includes this heat recovery method and provided a heat recovery apparatus and apparatus for combustible material processing in which use is made of the heat recovery method.

Description

Specification

Heat recovery method, combustible material processing method, heat recovery device, and combustible material processing device

[0001] The present invention makes use of the heat generated to melt ash when treating combustible materials such as municipal garbage, waste plastic, shredder dust, construction waste, waste tires, biomass, and the like. TECHNICAL FIELD The present invention relates to a heat recovery method capable of recovering heat, a method of treating combustibles, a heat recovery device, and a device of treating combustibles.

Background art

[0002] In recent years, a gasification melting method has been attracting attention as a method for incinerating waste such as garbage in Tokyo.

In this gasification and melting method, waste is partially burned at about 500 ° C to obtain a pyrolysis gas, and this pyrolysis gas is burned at a high temperature in a melting furnace to melt the ash contained in the gas. It is. The pyrolysis gas obtained by this method is obtained by partial combustion of waste, and has a low calorific value due to the mixing of combustion gas. Therefore, when trying to obtain a temperature sufficient to melt the ash in the melting furnace, that is, a temperature of about 1200 ° C, the waste to be input may have a calorific value of about 7-8 Mj / kg. is necessary.

[0003] The amount of heat generated varies greatly when waste, particularly municipal waste, is supplied while supplementary fuel is supplied to a melting furnace or the like when the amount of generated heat is insufficient. In fact, it is necessary to use oxygen instead of air as the oxygen supply source for combustion. Therefore, there is a problem that the running cost increases and the initial cost increases by installing an oxygen generator.

[0004] Furthermore, the ash contained in the pyrolysis gas flowing into the melting furnace contains, in addition to silica, alumina and calcium-based ones, low melting point metals and low boiling point metal salts. The components to be melted in the furnace are mainly silica, alumina, and luciferous, and low-boiling metal salts and the like flow out of the melting furnace downstream along with the combustion gas.

[0005] In the melting furnace, ash in the gas is caused to collide with the wall surface of the melting furnace by inertia force by means such as forming a swirling flow of the gas inside and, in many cases, suddenly reversing the gas flow. To form a slag stream to increase the melting rate of the ash contained in the material to be melted. Structure is adopted. Therefore, large particles are trapped in the slag flow, and the particle size of the ash in the exhaust gas flowing downstream from the melting furnace is often less than 10 microns.

[0006] As described above, the ash in the gas flowing downstream of the melting furnace is characterized by a high salt concentration and a very small particle size, which causes various problems. From the high temperature range of 1200 ° C or more immediately after melting to the temperature range of about 400 ° C, the fine particles melted at each temperature adhere to the heat transfer surface of the equipment provided for heat recovery and transfer to the heat transfer surface. The heat coefficient is extremely reduced.

[0007] If the heat transfer coefficient decreases, the function of the heat recovery equipment deteriorates such that the gas temperature cannot be lowered. Therefore, the gas temperature at the heat recovery process outlet rises, and the gas is installed downstream of the heat recovery process. There is a possibility that the temperature may exceed the allowable temperature of the dust collection step such as a bag filter. In particular, since the filter cloth of the bag filter is vulnerable to heat, the temperature at the entrance of the dust collection process must be lower than the allowable temperature. For this reason, a gas cooling process of the water spray method is provided in advance, or the heat transfer surface of the heat recovery device has sufficient heat transfer area to maintain the function of the heat recovery device sufficiently. The gas temperature in the section must be kept from exceeding the allowable temperature. This causes a cost increase due to an increase in equipment.

[0008] FIG. 1 is a diagram showing a process flow of a combustible material processing apparatus employing a conventional gasification and melting method (see Patent Document 1). The combustible material processing apparatus includes a gasification furnace 101, a melting furnace 102, a boiler 103, an economizer or an air preheater 104, a gas cooling tower 105, a bag filter 106, an induction blower 107, a catalytic denitration tower 108, and a chimney 109. . The combustibles are supplied to the gasifier 101, where they are partially burned and thermally decomposed to generate pyrolysis gas, tar, char, fly ash and the like. The pyrolysis gas containing the tar, char, fly ash and the like is supplied to the melting furnace 102 in its entirety.

[0009] In the melting furnace 102, the pyrolysis gas is burned at a high temperature of 1200 ° C or more, the ash is melted and discharged out of the furnace as molten slag, and the high-temperature combustion gas discharged from the melting furnace is guided to the boiler 103. I will be. The combustion gas is cooled to about 450 ° C. in the boiler 103, and further cooled to about 200 ° C. in the economizer or the air preheater 104.

[0010] The ash contained in the high temperature combustion gas exiting the melting furnace 102 has a small particle size and a comparative A high percentage of metal salts having a low melting point, so that the adhesion is high, so that the metal salt easily adheres to the heat transfer surface of the boiler 103, economizer or air preheater 104. Therefore, as the operation continues, it gradually adheres to the heat transfer surface of the boiler 103, the economizer or the air preheater 104 and lowers the heat transfer coefficient. As the operation time elapses, it gradually cools down and the inlet temperature of the bag filter 106 rises.

[0011] Generally, the heat resistance temperature of the bag filter is about 220 ° C, so that the combustion gas must be sprayed with the gas cooling tower 105 to cool it so that the temperature does not exceed that temperature. However, even if the operation is continued in this way, the progress of ash deposition on the heat transfer surface does not stop, and the temperature of the combustion gas at the inlet of the air preheater gradually increases, and the deposition becomes more severe. In a temperature range exceeding 450 ° C, the ash is in a semi-molten state, and it is difficult to mechanically remove or remove the ash, for example. It is difficult to stop. That is, once the function of the heat transfer surface has been reduced, it is difficult to suppress the progress of ash deposition in that state.

[0012] Therefore, in the conventional combustible material processing apparatus, the heat transfer area of the boiler 103, the economizer, or the air preheater 104, which is a heat recovery step, has a sufficient safety factor and is attached to the heat transfer surface. Stable operation could not be continued except by providing means for forcibly removing ash. The ash attached to the heat transfer surface is forcibly removed while the force is applied, causing a significant change in the surface temperature of the heat transfer surface, and the protective coating formed on the heat transfer surface peels off due to thermal shock, resulting in corrosion of the heat transfer surface. Wear may be accelerated.

[0013] In addition, if the ash collected by the bag filter 106 is to be returned to the melting furnace 102 in order to increase the ash melting rate, the ash is not converted into molten slag in the melting furnace but is directly transferred to exhaust gas. A large amount of the low-melting-point substances and metal salts that are circulated in large quantities in the circulation path including the heat exchanger may accelerate the deposition of ash on the heat transfer surface of the heat exchanger. There was a problem that the rate of reclaimed ash could not be increased, and the rate of slag conversion could only be increased below a certain limit.

[0014] On the other hand, in recent years, as a method of not using auxiliary fuel for melting ash, the calorific value of the pyrolysis gas has to be increased as much as possible rather than leading the partial combustion type pyrolysis gas to the full melting furnace. In order to make it easier to maintain the temperature of the melting furnace, there has been proposed a method of applying a pyrolysis furnace that approximates the carbonization method without using oxygen as much as possible. FIG. 2 is a diagram showing a process flow of another processing device.

In FIG. 2, portions denoted by the same reference numerals as those in FIG. 1 indicate the same or corresponding portions. This combustible treatment system has a gasification furnace and a melting furnace, as in the conventional example, but the gasification furnace is an integrated fluidization chamber divided into a pyrolysis chamber 110-1 and a combustion chamber 110-2. A floor gasifier 110 is employed. The combustibles are mainly supplied to the pyrolysis chamber 110-1 side of the fluidized bed gasifier 110, where they generate pyrolysis gas, tar, char, fly ash and the like. Of these, those that do not remain in the fluidized bed are all supplied to the melting furnace 102, where they are burned at a high temperature of 1200 ° C or more, and the ash is melted.

[0016] On the other hand, the pyrolysis residue remaining in the fluidized bed flows into the combustion chamber 110-2 together with the fluidized medium. Fluidized air and secondary air are supplied so that the fluidized bed of the combustion chamber 110-2 is maintained at about 550 ° C to 700 ° C, and the freeboard above the fluidized bed is maintained at 850 ° C to 950 ° C. The total air ratio is maintained at 1 or more and complete combustion is performed. In some cases, the pyrolysis residue flowing through the pyrolysis chamber 110-1 may simply be burned into the combustion chamber 110-2, but the waste is directly supplied according to the pyrolysis and combustion characteristics of the waste. You can.

The combustion gas discharged from the combustion chamber 110-2 is introduced at a temperature of 850 ° C. to 950 ° C. into a dust collecting device 112 such as a cyclone. The ash particles collected by the dust collector 112 are guided to the melting furnace 102 and melted.

The apparatus for treating combustibles having the above configuration has an excellent advantage that ash can be melted without using auxiliary fuel even for combustibles having a low calorific value, but the gas flowing into the boiler 103 The particles contained therein are collected by the melting furnace 102 on the side of the pyrolysis chamber 110-1 and by the dust collector 112 such as a cyclone on the side of the combustion chamber 110-2, so that very fine particles (particle size) (Small particles), which is not preferable from the viewpoint of preventing adhesion to the heat transfer surface of the boiler 103, the economizer, or the air preheater 104 as described above.

Patent Document 1: Japanese Patent No. 3153091

Disclosure of the invention

Problems the invention is trying to solve [0020] The present invention has been made in view of the above points, and it is possible to melt ash without the need of auxiliary fuel even for a combustible substance having a low calorific value of 6-7 Mj / kg, and to burn after the ash is melted. Even when recovering heat from gas, ash deposition on the heat transfer surface of the heat recovery device (boiler, economizer or air preheater) is suppressed, the margin of the heat transfer surface is minimized, and water spray gas cooling is used. An object of the present invention is to provide a heat recovery method, a method for treating combustible materials, a heat recovery device, and a device for treating combustible materials, which can eliminate the need for facilities such as facilities.

Means for solving the problem

[0021] In order to solve the above problem, the heat recovery method according to the invention of claim 1 recovers heat from the first gas G2 accompanied by many particles having a large particle size as shown in FIG. 3, for example. And a step of recovering heat by mixing the first gas G2 from which heat has been recovered with a second gas G3 accompanied by many particles having a small particle size.

[0022] As described above, heat is recovered from the first gas containing many particles having a large particle diameter, and then the second gas containing many particles having a small particle diameter is mixed. The polishing function of polishing the heat transfer surface when particles having a large particle size collide with the heat transfer surface makes it possible to adhere the particles, particularly small particles having a small particle size that easily adhere to the heat transfer surface in the second gas. Can prevent the adhesion of heat to the heat transfer surface.

In the invention according to claim 2, in the heat recovery method according to claim 1, for example, as shown in FIG. 3, the first gas G2 supplies combustibles to the fluidized bed furnace 1 The second gas G3 was obtained by introducing the gas G1 generated in the fluidized-bed furnace 1 into the melting furnace 2 and melting the ash content. Consists of a gas with particles.

[0024] The gas generated in the fluidized bed furnace by supplying the combustibles to the fluidized bed furnace is a gas accompanied by a large number of particles having a large particle diameter, and the gas generated in the fluidized bed furnace is introduced into the melting furnace. The gas obtained by melting the ash is a gas accompanied by particles having a small particle size, so the gas generated in the fluidized bed furnace is the first gas, and the gas obtained in the melting furnace is the second gas. By doing so, the same operation as the invention described in claim 1 can be obtained.

[0025] In the invention according to claim 3, as shown in Fig. 5, for example, in the heat recovery method according to claim 2, the combustible material 34 is thermally decomposed in the fluidized bed furnace 1 (21). A step of obtaining a gas and a gas G1 by burning, and a step of burning the char in the furnace 1 (22). Configuration like this By doing so, it is possible to generate fine particles and combustible gas from combustibles efficiently and in a manner in which the composition fluctuation of the gas is reduced.

[0026] In the invention according to claim 4, for example, as shown in Fig. 5, in the heat recovery method according to claim 3, a step of burning the char in the combustion chamber 22; Steps D and E for flowing the fluid medium into the pyrolysis chamber 21 for pyrolyzing the combustibles 34 are provided. With this configuration, the heat generated by burning the chamber in the combustion chamber is transferred to the fluid medium, and this heat can be effectively used for the pyrolysis reaction of combustibles in the pyrolysis chamber.

In the invention according to claim 5, according to the heat recovery method according to any one of claims 2 to 4, for example, as shown in FIG. 3, the first gas G2 and the second gas A step of mixing G3, a step of cooling the mixed gas to 450 ° C or lower, a step of separating solids in the gas cooled by the dust collector 5, and a step of introducing the separated solids into the melting furnace 2. And melting. The gas temperature after cooling is 450 ° C. or less, preferably 350 ° C. or less, more preferably 300 ° C. or less, and most preferably 250 ° C. or less.

[0028] In the method for treating combustibles according to the invention as set forth in claim 6, for example, as shown in Fig. 3, the first gas G2 containing particles and the second gas G1 containing particles in the fluidized bed gasifier 1 are used. Generating step, introducing the first gas G2 from the fluidized bed gasifier 1 into the heat recovery unit 3, and performing heat exchange between the introduced gas G2 and the heat receiving fluid to recover heat. A step of introducing the second gas G1 from the fluidized bed gasifier 1 into the melting furnace 2 to melt the ash in the particles, and a step of introducing the gas G3 in which the ash is melted into the heat recovery unit 3. And

[0029] As described above, the first gas from the fluidized-bed gasification furnace is introduced into the heat recovery device to recover heat, and the second gas from the fluidized-bed gasification furnace is introduced into the melting furnace. Since the gas discharged from the furnace is introduced into the same heat recovery device, the first gas is a gas accompanied by many particles with a large particle size. This can prevent the particles from adhering to the heat transfer surface.

[0030] In the method for treating combustible material according to the invention of claim 7, for example, as shown in FIG. 3, the first gas G2 and the second gas G1 containing particles in the fluidized-bed gasification furnace 1 are mixed. Generating the first gas G2 from the fluidized bed gasifier 1 into the heat recovery unit 3, and Heat exchange between the collected gas G2 and the heat receiving fluid to recover heat, and introducing the second gas G1 from the fluidized bed gasifier 1 into the melting furnace 2 to melt the ash in the particles And a step of introducing the gas G3 in which the ash is melted into the heat recovery device 3 into which the first gas G2 is introduced. Note that the heat recovery device that exchanges heat with the first gas and the heat recovery device that exchanges heat with the mixed gas of the first gas and the second gas may be the same or may be configured as separate devices. You can do it.

[0031] As described above, the first gas accompanied by many particles having a large particle diameter from the fluidized bed gasifier is introduced into the heat recovery device to recover heat, and then the heat is recovered by the recovered gas. By mixing the second gas with many small particles discharged from the melting furnace and recovering heat, the large particles in the first gas collide with the heat transfer surface. The polishing function can prevent particles from adhering to the heat transfer surface.

[0032] In the invention according to claim 8, in the method for treating a combustible material according to claim 6 or 7, for example, as shown in Fig. 3, the first gas G2 and the second gas G3 are heated. A step of recovering heat in the recovery devices 3 and 4 and cooling it to 450 ° C or lower, a step of separating solids in the first gas G2 and the second gas G3 by the dust collector 5, and a step of separating the separated solids. Into the melting furnace 2 to be melted. The gas temperature after cooling is 450 ° C or less, preferably 350 ° C or less, more preferably 300 ° C or less, and most preferably 250 ° C or less.

[0033] The heat recovery apparatus according to claim 9 includes, for example, as shown in FIG. 3, a first inlet for introducing a first gas G2 containing many particles having a large particle diameter, The second inlet, which is located downstream of the first inlet with respect to the flow of the gas G2 introduced from the first inlet and introduces the second gas G3 containing many small-sized particles, In order to recover heat by exchanging heat between the discharge port for discharging gas G4 after recovering heat and the gases G2 and G3 introduced from the first and second inlets and the heat receiving fluid, And a heat transfer surface.

[0034] As described above, downstream of the first inlet for introducing the first gas containing many particles having a large particle diameter, the second gas for introducing the second gas containing many particles having a small particle diameter is provided. Since the inlet is provided, the polishing function when particles having a large particle diameter in the first gas introduced from the first inlet impinge on the heat transfer surface allows the particles to adhere, particularly the second inlet. It is possible to prevent adhesion of particles having a small particle diameter in the second gas which is likely to be introduced from the mouth and adheres. Also, the first entrance By providing the gas upstream of the second inlet, the first gas containing many particles having a large particle size is cooled, and then the second gas containing many particles having a small particle size is mixed. In other words, a region where a high-temperature gas containing particles having a small particle diameter that easily adheres to the heat transfer surface is not formed as much as possible.

In the invention according to claim 10, in the heat recovery device 3 according to claim 9, for example, as shown in FIG. 3, the first gas G2 supplies combustibles to the fluidized bed furnace 1 The second gas G3 is a gas generated in the fluidized bed furnace 1, and is obtained by introducing the gas G1 generated in the fluidized bed furnace 1 into the melting furnace 2 and melting the ash contained in the gas. Gas.

[0036] The gas generated in the fluidized bed furnace by supplying combustibles to the fluidized bed furnace is a gas accompanied by a large number of particles having a large particle diameter, and the gas generated in the fluidized bed furnace is introduced into the melting furnace. Since the gas obtained by melting the ash is a gas accompanied by particles having a small particle size, the gas generated in the fluidized bed furnace is used as the first gas, and the gas obtained in the melting furnace is used as the second gas. By introducing the heat into the heat recovery device through the first inlet and the second inlet, respectively, the same operation as the invention described in claim 9 can be obtained.

In the invention according to claim 11, in the heat recovery device 3 according to claim 10, for example, as shown in FIG. 3, after mixing the first gas G2 and the second gas G3, After cooling to 450 ° C. or less, the solid content in the mixed gas G2, G3 is separated by the dust collecting device 5, and the separated solid content is introduced into the melting furnace 2 to be melted. . The gas temperature after cooling is 450 ° C or less, preferably 350 ° C or less, more preferably 300 ° C or less, and most preferably 250 ° C or less.

[0038] The combustible material processing apparatus according to the twelfth aspect of the present invention generates a first gas G2 and a second gas G1 containing particles by gasifying the combustible material as shown in Fig. 3, for example. A fluidized-bed gasifier 1, a first gas G2 generated in the fluidized-bed gasifier 1, and a heat recovery device 3 for exchanging heat with a heat-receiving fluid to recover heat. The melting furnace 2 for introducing the second gas G1 generated in the gasification furnace 1 to melt the ash, and the gas G3 discharged from the melting furnace 2 together with the particles further generated in the melting furnace 2 together with the heat recovery unit 3 is provided with a gas introduction channel.

[0039] As described above, the first gas containing particles generated in the fluidized bed gasifier is introduced to recover heat. The second gas generated in the fluidized bed gasification furnace is introduced into the melting furnace and the gas discharged from the melting furnace is introduced into the heat recovery unit, so that the particles in the first gas transfer heat. The polishing function at the time of collision with the surface can prevent the adhesion of particles, particularly the adhesion of the particles discharged from a melting furnace containing particles having a small particle diameter that easily adheres.

The apparatus for treating a combustible material according to the invention of claim 13 generates the first gas G2 and the second gas G1 containing particles by gasifying the combustible material as shown in FIG. 3, for example. A fluidized-bed gasifier 1, a first gas G2 generated in the fluidized-bed gasifier 1, and a heat recovery device 3 for exchanging heat with a heat-receiving fluid to recover heat. The melting furnace 2 for introducing the second gas G1 generated in the gasification furnace 1 to melt the ash, and the gas G3 discharged from the melting furnace 2 together with the particles further generated in the melting furnace 2, And a gas introduction passage for introducing the heat recovery device 3 into which the first gas G2 is introduced. Note that the heat recovery device that performs heat exchange with the first gas and the heat recovery device that performs heat exchange with a mixed gas of the first gas and the second gas may be the same or may be configured as separate devices. You may.

In the invention according to claim 14, in the apparatus for treating combustibles according to claim 12 or 13, for example, as shown in FIG. 5, the fluidized-bed gasifier 1 thermally decomposes the combustibles 34. Then, a pyrolysis chamber 21 that generates the second gas G1, a combustion chamber 22 that burns the channel to generate the first gas G2, and a fluid medium from the combustion chamber 22 are moved to the pyrolysis chamber 21. And a flow path D and E for the use.

[0042] In the invention according to claim 15, for example, as shown in FIG. 3, in the combustible material processing apparatus according to claim 14, the second gas G1 from the pyrolysis chamber 11 is supplied to the melting furnace 2. A flow path for introduction and a flow path for introducing the first gas G2 from the combustion chamber 12 into the heat recovery device 3 are provided.

The invention according to claim 16 is, for example, as shown in FIG. 3, in the combustible material treatment apparatus according to any one of claims 12 to 15, and the heat recovery apparatus 3 is a waste heat boiler. is there.

In the invention according to claim 17, in the apparatus for treating a combustible material according to any one of claims 12 to 16, as shown in FIG. 3, for example, as shown in FIG. After mixing the gas G1 of No. 2 and cooling it to 450 ° C or less, the solid content in the mixed gas is separated by the dust collector 5, and the separated solid content is introduced into the melting furnace 2 and melted. ing. Note that the gas after cooling The temperature is below 450 ° C, preferably below 350 ° C, more preferably below 300 ° C, most preferably below 250 ° C.

[0045] The apparatus for treating combustible material according to the invention according to claim 18 generates a first gas G2 and a second gas G1 containing particles by gasifying the combustible material as shown in Fig. 8, for example. Fluidized bed gasifier 1, a solids separator 12 that collects particles in the first gas G2 generated in the fluidized bed gasifier 1, and a second separator generated in the fluidized bed gasifier 1 And a melting furnace 2 that burns the gas G1 and melts the particles collected by the solid separator 12 and generates a flammable gas G5. Here, the solid separator that collects the particles is not only a filter that filters and collects the particles when the first gas containing the particles passes, but also has a difference in density like a cyclone, for example. Includes devices that separate solids from gases. With this configuration, no combustion gas is introduced into the melting furnace, and only large particles including ash are introduced. Therefore, even if the calorific value of the combustible is as low as 6-7 Mj / kg, for example, 1200 It is burned at a high temperature of ° C or higher and can melt ash without the need for a combustion aid.

[0046] This application is based on Japanese Patent Application No. 2003-0111496 filed in Japan on January 20, 2003 and Japanese Patent Application No. 2004-012419 filed on January 20, 2004. The contents of which form part of the present application.

Also, the present invention may be more completely understood by the following detailed description. However, the detailed description and specific examples are preferred embodiments of the present invention, and have been described for illustrative purposes only. From this detailed description, various changes and modifications will be apparent to those skilled in the art without departing from the spirit and scope of the invention.

Applicant may disclose any of the disclosed modifications or alternatives which are not intended to be publicly available to any of the described embodiments and which may not be literally within the scope of the claims. It is part of the invention under discussion.

The use of nouns and similar designations in the present specification and claims should be interpreted to include both the singular and the plural unless specifically stated otherwise or otherwise clearly contradicted by context. The use of any example or exemplary term provided herein (eg, "such as") is merely intended to facilitate the description of the invention, and is not particularly defined in the following claims. Unless otherwise limited in scope of the invention Not something.

The invention's effect

[0047] As described above, according to the invention described in each claim, the following excellent effects can be obtained.

[0048] According to the inventions set forth in claims 1 to 5, the first gas power and heat which accompany many particles having a large particle diameter are recovered, and the particles having a large particle diameter are accompanied in the next step. Since the second gas is mixed, the polishing function of polishing the heat transfer surface when particles having a large particle diameter in the first gas collides with the heat transfer surface allows the particles to adhere, particularly the second gas. It is possible to provide a heat recovery method capable of preventing particles having a small particle diameter that easily adheres to the heat transfer surface in the heat transfer surface.

[0049] According to the invention set forth in claims 6 and 7, the first gas from the fluidized-bed gasifier is introduced into the heat recovery device to recover heat, and the second gas from the fluidized-bed gasifier is recovered. Is introduced into the melting furnace, and the gas discharged from the melting furnace is introduced into the heat recovery device. Therefore, the first gas is a gas accompanied by a large number of particles having a large particle size. The polishing function at the time of colliding with the surface can provide a method for treating combustible materials that can prevent particles from adhering to the heat transfer surface.

[0050] According to the invention described in claim 8, the first gas accompanied by many particles having a large particle diameter from the fluidized-bed gasification furnace is introduced into the heat recovery device to recover heat, By mixing this recovered gas with the second gas accompanied by many small particles discharged from the melting furnace and recovering the heat, the large particle diameter in the first gas is recovered. The polishing function when particles collide with the heat transfer surface can provide a method for treating combustible materials that can further prevent particles from adhering to the heat transfer surface.

[0051] According to the inventions set forth in claims 9 to 11, the second gas containing many particles having a small particle size is provided downstream of the first inlet for introducing the first gas containing many particles having a large particle size. Since the second inlet for introducing the second gas is provided, the polishing function when the large-diameter particles in the first gas introduced from the first inlet collide with the heat transfer surface causes the particles to be removed. It is possible to provide a heat recovery device capable of preventing the adhesion, particularly the adhesion of particles having a small particle diameter in the second gas which is easily attached from the second inlet. In addition, by providing the first inlet upstream of the second inlet, the first gas containing many particles having a large particle size is cooled, and then the first gas is cooled. As a result, the second gas containing many particles having a small diameter is mixed, and a region in which a high-temperature gas containing particles having a small particle diameter easily adheres to the heat transfer surface is not formed as much as possible.

[0052] According to the invention as set forth in claims 12 to 17, the fluidized-bed gasification furnace is provided in a heat recovery device that introduces the first gas containing fine particles generated in the fluidized-bed gasification furnace to recover heat. Since the second gas generated in the above step is introduced into the melting furnace and the gas discharged from the melting furnace is introduced, the polishing function when the particles in the first gas collide with the heat transfer surface causes the particles to be removed. It is possible to provide a combustible material treatment apparatus capable of preventing gas discharged from a melting furnace containing small particles having a small particle diameter, which is easily adhered, in particular, from adhering the fine particles.

[0053] According to the invention set forth in claim 18, the second gas containing fine particles generated in the fluidized bed gasifier and the large particles contained in the first gas generated in the fluidized bed gasifier are Is introduced into the melting furnace to melt the ash, so that the ash can be melted without using a combustion aid even if the combustible has a low calorific value.

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 3 is a view showing a process flow of the combustible material processing apparatus according to the present invention. As shown in the figure, the combustibles processing equipment is as follows: gasifier 1, melting furnace 2, boiler 3, heat recovery equipment such as economizer or air preheater 4, dust collecting equipment such as cyclone 5, gas cooling tower 6, bag filter It has a configuration including an induction blower 8, a catalytic denitration tower 9 and a chimney 10. The gasification furnace 1 employs an integrated fluidized bed gasification furnace divided into a pyrolysis chamber 111 and a combustion chamber 112. The gasifier 1 is connected to a combustible material supply device for supplying a combustible material to an external force. The combustible material supply device 36 includes, for example, a hopper that receives combustible materials, a screw that crushes the combustible materials received by the hopper and sends the crushed combustible materials to the gasifier 1, and a flow path for combustible materials.

[0055] The combustibles are mainly supplied from the combustibles supply means 36 to the pyrolysis chamber 11 side of the gasifier 1, where they are pyrolyzed to generate pyrolysis gas, tar, char, fly ash and the like. generate. Of these, pyrolysis gas G1 including tar, char, fly ash, etc. that does not remain in the fluidized bed is all supplied to melting furnace 2, where it is burned at a high temperature of 1200 ° C or more, and the ash content is reduced. It is melted and discharged out of the melting furnace 2 as molten slag. On the other hand, the pyrolysis residue remaining in the fluidized bed of the pyrolysis chamber 111 of the gasification furnace 1 flows into the combustion chamber 1-2 together with the fluidized medium. The fluidized bed in the combustion chambers 1 and 2 is maintained at around 550 ° C to 700 ° C, and the freeboard above the fluidized bed is maintained at 850 ° C to 950 ° C. Secondary air is supplied to the upper part of the free board, and the total air ratio is maintained at 1 or more, and complete combustion is performed. In some cases, the combustion chambers 1 and 2 may simply burn the pyrolysis residue flowing through the pyrolysis chambers 1 and 1, but supply the combustibles directly according to the pyrolysis and combustion characteristics of the combustibles. May be.

[0057] Combustion gas G2 discharged from the combustion chambers 112 of the gasification furnace 1 flows into the boiler 3 at a temperature of 850 ° C-950 ° C through a flow path composed of pipes and the like, and reaches 700 ° C. After being cooled to about ° C, it is mixed with the high-temperature combustion gas G3 discharged from the melting furnace 2. The mixing is performed at such a point that the gas temperature after mixing does not exceed 1100 ° C, preferably 1050 ° C, and more preferably 1000 ° C. If the temperature of the mixed gas is too high, a part of the ash contained in the mixed gas may be melted, and a trouble may be caused to adhere to the inner surface of the boiler tube ボ of the boiler 3. It should be lower than the temperature. If the temperature of the mixed gas is too low, a part of the tar in the mixed gas may be condensed, causing a trouble to adhere to the inner surface of the boiler tube of the boiler 3; C or higher, preferably 500 ° C or higher.

[0058] The mixed combustion gas G4 is cooled to about 450 ° C in the boiler 3, and further cooled to about 200 ° C in a heat recovery device 4 such as an economizer or an air preheater. The dust is removed by the dust collector 5. These devices are also connected by a combustion gas flow path composed of piping and the like. The ash 11 collected by the dust collecting device 5 is returned to the melting furnace 2 through a flow path constituted by a pipe or the like, and is melted in the melting furnace 2. A heat exchanger such as an economizer or an air preheater may be omitted, in which case dust will be collected at a temperature of 450 ° C or less. The dust collection temperature is preferably 350 ° C or less, more preferably 300 ° C or less, and most preferably 250 ° C or less. The conditions of 350 ° C or lower are preferable because inexpensive carbon steel can be used as the material of the dust collecting device, and the power to greatly reduce the corrosion conditions. Also, as the temperature decreases to 300 ° C or lower and 250 ° C or lower, the probability that the low-melting-point metal exists in the solid state increases. It is reduced. In the present combustible material treatment apparatus, the combustion gas G4 after dust removal passes through the gas cooling tower 6 and is finally removed by the bag filter 7. In the present invention, the gas cooling tower 6 In many cases, it can be omitted.

[0059] Ash gas particles are contained in the combustion gas emitted from incinerating combustible materials such as municipal waste, waste plastic, shredder dust, construction waste, and waste tires. It is determined by various factors, such as the physical properties of the material, chemical changes associated with the combustion reaction, and the rise in combustion gases. In general, the ash that comes out of incineration of garbage varies depending on the type of incinerator, but the combustion gas that has passed through the melting furnace 2 is a large particle with a particle size of several tens to 100 microns. The ash particles contained in these are small particles of almost 10 microns or less.

[0060] Fluidized bed incinerators, which had been adopted as incinerators for a large number of garbage before the gasification and melting furnace was commercialized, are highly reliable incineration technologies. The ash particles in the exhaust gas introduced into the treatment process had a large amount of silica, alumina and luciferic components in the components and relatively large particle sizes. For this reason, ash deposition on the heat transfer surfaces of equipment used in the heat recovery process, such as boilers, economizers, and air preheaters, did not become a major problem.

[0061] Since the combustion gas G2 discharged from the combustion chambers 112 of the gasifier 1 in the combustible material processing apparatus of the present embodiment does not pass through the melting furnace 2, the ash particles in the combustion gas G2 Properties' shape · Size is the same as the properties, shape and size of ash particles in the combustion gas discharged from a conventional fluidized bed incinerator, and the heat from a boiler 3 and an economizer or an air preheater with a large particle size. There is no danger of causing trouble by adhering to the heat transfer surface of the equipment used in the heat recovery process of the recovery equipment 4.

[0062] The pyrolysis gas G1 from the pyrolysis chamber 11 of the gasification furnace 1 is introduced into the melting furnace 2 and burned through a flow path composed of pipes and the like. Since the combustion gas G3 discharged from the melting furnace 2 passes through the melting furnace 2, the combustion gas contains fine ash particles in the same manner as the conventional combustion gas discharged from the gasification melting furnace. According to the results of the tests conducted by the present inventors, when wastes were treated in the gasifier 1 which is an integrated fluidized bed gasifier, the pyrolysis gas G1 from the pyrolysis chamber 111 was used. The ratio of the gas amount of the combustion gas G2 from the combustion chambers 1-2 to the gas amount of the combustion gas G2 from the combustion chambers 1-2 is about 1: 3. Therefore, the gas after mixing in boiler 3 Ash particle size distribution is relatively close to that of conventional fluidized bed incinerators and adheres to the heat transfer surface of equipment used in the heat recovery process of boiler 3 and heat recovery equipment 4 such as an economizer or air preheater There is little risk of causing trouble.

[0063] The combustion gas G3 discharged from the melting furnace 2 contains many ash particles having a small particle diameter as described above. Since the small-sized ash particles of the combustion gas G3 adhere to the heat transfer surface of the boiler 3, if only the combustion gas G3 is introduced into the boiler 3, the ash adhesion to the heat transfer surface is promoted. Here, the combustion gas G2 discharged from the combustion chambers 112 of the gasifier 1 is also introduced into the boiler 3. Since this combustion gas G2 contains a large amount of ash particles having a large particle diameter, the ash particles having a large particle diameter have a function of polishing a portion of the ash particle when the ash particle collides with the heat transfer surface. It has the effect of preventing adhesion. Therefore, when the combustion gas G2 from the combustion chamber 1-2 and the combustion gas G3 from the melting furnace 2 are introduced into the boiler 3, the combustion gas G2 is merged with the combustion gas G3 and introduced. An inlet is provided upstream of the combustion gas G3 inlet, and the combustion gas G2 is introduced from the upstream side of the combustion gas G3 to create an area where only the combustion gas G3 mixed with ash particles having a small particle size exists. I need to do it.

[0064] Further, by providing the inlet for the combustion gas G2 upstream of the inlet for the combustion gas G3, the combustion gas G2 from the combustion chamber 1-2 is cooled in the boiler 3 and then melted. As a result, the high-temperature combustion gas G3 from the furnace 2 is mixed, so that the region where the high-temperature gas including the molten slag particles that easily adhere to the heat transfer surface exists is not formed as much as possible.

FIG. 4 is a diagram showing a process flow of another combustible material processing apparatus according to the present invention. As shown in the figure, the ash 13 collected by the bag filter 12 as a solid separator disposed downstream of the gas cooling tower 6 is supplied to the melting furnace 2 and melted. Note that, instead of the bag filter 12, a solid separator such as a cyclone may be provided. In this case, when the entire amount of the collected ash 13 is supplied to the melting furnace 2, fine ash may be trapped in the system and circulated, and therefore, by operating the control valves VI and V2, a part 13a of the ash 13 may be removed. Remove it. Activated carbon 14 is added to the combustion gas G4 discharged from the bag filter 12, a harmful substance is adsorbed on the activated carbon 14, and the activated carbon 14 adsorbing the harmful substance is collected and removed by the bag filter 7.

FIG. 5 is a diagram showing a configuration example of an integrated fluidized bed gasification furnace, which is an example of the gasification furnace 1.

Gasifier 1 has a pyrolysis chamber 21 (corresponding to pyrolysis chambers 1 and 1), a combustion chamber 22 (corresponds to combustion chambers 1 and 2), A heat recovery chamber 23 is provided. The combustibles 34 supplied to the pyrolysis chamber 21 are pyrolyzed while being stirred by the fluid medium swirling in the pyrolysis chamber 21 indicated by the arrow F in the figure, and the pyrolysis gas, tar, char, fly ash And so on. The pyrolysis gas G1 containing tar, char, fly ash, etc. flows into the melting furnace 2 as shown in FIGS. Un-pyrolyzed products such as tar and char remaining in the fluidized bed of the pyrolysis chamber 21 flow into the combustion chamber 22 through the opening 26 of the partition wall 25 as shown by the arrow A, along with the fluid medium. In this way, the unpyrolyzed products such as chars which flow into the combustion chamber 22 from the pyrolysis chamber 21 are burned in the combustion chamber 22 to generate the combustion gas G2, and the combustion heat heats the fluid medium. The combustion gas G2 flows into the boiler 3, as shown in FIGS.

[0067] The fluid medium heated by the combustion of the unpyrolyzed products such as tar and char, which has been burned in the combustion chamber 22, passes through the upper end of the partition wall 24 as shown by the arrow B and enters the heat recovery chamber 23. After flowing into the heat recovery chamber 23, the heat is absorbed by the in-layer heat transfer tube 27 disposed below the interface and cooled, and then the lower opening 28 of the partition wall 24 as shown by arrow C Through the combustion chamber 22 again. Further, the fluid medium heated in the combustion chamber 22 flows over the upper end of the partition wall 29 into the settling chamber between the partition wall 29 and the partition wall 30 as shown by the arrow D, and further shown by the arrow E. Flows into the pyrolysis chamber 21 through the lower opening 31 of the partition wall 30 as described above. As described above, the gasification furnace 1 is formed with a flow path of the fluid medium. The flow of the fluid medium is regulated by fluidizing gases 32 and 33.

FIG. 6 is a diagram showing a configuration example of a fluidized bed gasification furnace of a two-tower type fluidized bed system which is an example of the gasification furnace 1. As shown in FIG. As shown in the figure, the gasification furnace 1 is provided with a pyrolysis fluidized bed furnace 41 (corresponding to the pyrolysis chamber 11) and a combustion fluidized bed furnace 42 (corresponding to the combustion chamber 12). The two inclined pipes ₄₃ and 44 communicate with each other, and the fluid medium is circulated between the two layers through the inclined pipes 43 and 44, thereby supplementing the heat required for pyrolysis.

That is, when the combustible material is supplied to the thermal decomposition fluidized bed furnace 41, it is thermally decomposed and generates pyrolysis gas, fire, ash, fly ash and the like. The pyrolysis gas G1 containing char and fly ash flows into the melting furnace 2 as shown in FIGS. The unpyrolyzed products such as chars remaining in the fluidized bed of the pyrolysis fluidized-bed furnace 41 flow into the combustion fluidized-bed furnace 42 through the inclined pipe 43 along with the fluidized medium, where they are burned and combusted by the combustion gas. G2 is emitted and the fluid medium is added by the heat of combustion. The heated and heated fluid medium flows into the thermal decomposition fluidized bed furnace 41 through the inclined pipe 44 and is used as a heat source for thermal decomposition of combustibles.

[0070] The combustion gas G2 is supplied to the boiler 3, as shown in Figs. In this two-column fluidized-bed fluidized-bed gasifier, the pyrolysis gas G1 contains no combustion gas, so that a pyrolysis gas G1 with a high gas calorific value is obtained, and this gas is supplied to the melting furnace. Therefore, even if the calorific value is as low as 67 MjZkg, even for combustible materials, high-temperature combustion of 1200 ° C or more can be performed without supplying auxiliary fuel in a melting furnace, and ash can be melted. be able to . As the fluidized gas 45 of the fluidized bed of the pyrolysis fluidized bed furnace 41, a gas containing no oxygen, for example, steam, carbon dioxide gas, or nitrogen gas is used, and as the fluidized gas 46 of the fluidized bed of the combustion fluidized bed furnace 42. Is a gas containing oxygen such as air.

FIG. 7 is a diagram showing one configuration example of the melting furnace 2. The melting furnace 2 includes a primary combustion chamber 51, a secondary combustion chamber 52, and a tertiary combustion chamber 53. As shown in FIGS. 3 and 4, the pyrolysis gas G1 from the gasifier 1 flows into the primary combustion chamber 51 of the melting furnace 2, and the combustion gas (air, oxygen-enriched air, oxygen) 55 flows into the furnace. , Mixing while forming a swirling flow, burning and moving to the secondary combustion chamber 52 to perform high-temperature combustion (1200 ° C-1400 ° C, preferably 1350 ° C), and the combustion gas G3 is supplied to the tertiary combustion chamber 53. It is mixed with the combustion gas 55, where the unburned substances in the gas are completely burned and discharged as combustion gas G3. By this high-temperature combustion, the ash contained in the pyrolysis gas G1 and the ash 13 collected from the combustion gas G2 and supplied to the melting furnace 2 are melted and discharged as molten slag 56 from the slag discharge port 57 to the outside of the furnace. For discharging the molten slag 56 out of the system, for example, a method of providing a water tank below the slag discharge port 57 and dropping the molten slag 56 can be used. In the water tank, the molten slag 56 is cooled and pulverized into granular slag. The granular slag settled in the water tank is transported out of the system by the conveyor installed in the water tank. Gas G3 in the melting furnace is sealed with water in the water tank and does not leak out of the system.

FIG. 8 is a view showing a process flow of another combustible material processing apparatus according to the present invention. As shown in the figure, here, as in FIG. 4, the ash 13 collected by the bag filter 12 as a solid separator disposed downstream of the gas cooling tower 6 is supplied to the melting furnace 2 and melted. . Instead of the bag filter 12, a solid separator such as a cyclone may be provided. In this case, When the entire amount of the ash 13 is supplied to the melting furnace 2, fine ash may be trapped in the system and circulate. Therefore, a part 13a of the ash 13 is extracted by operating the control valves VI and V2.

The melting furnace 2 has a low calorie (4-6 kJ / Nm ³ (dry)) or a medium calorie (10 19 kj / Nm ³ (dry)) from the pyrolysis gas G1 from the pyrolysis chamber 1-1 of the gasifier 1. This is a melting furnace for obtaining the gas in (). When the pyrolysis gas G1 from the pyrolysis chamber 1-1 flows into the melting furnace 2 and gasifies at a high temperature of 1300 ° C or higher, the char and tar contained therein are completely gasified, and the ash is converted into molten slag. Discharge outside the furnace. Here, as the gasification gas, a gas selected from oxygen-enriched air, steam, oxygen, or a mixture thereof is supplied to the melting furnace 2 separately or together. The amount of oxygen in this gasified gas is adjusted to the pyrolysis gas G1, and the total amount of oxygen is set to 0.1-0.6 (melting amount) when the theoretical amount of oxygen required to completely burn the object is set to 1. (Oxygen ratio in the furnace), the low calorie or medium calorie combustible gas G5 can be obtained from the melting furnace 2.

[0074] The low calorie or medium calorie combustible gas G5 contains many useful gas components such as carbon monoxide C 一 and hydrogen H. Such flammable gas G from melting furnace 2

2

5 is recovered through a heat recovery device 15 such as a boiler, and then passed through a scrubber 16 to obtain an industrial fuel gas or a chemical industrial raw material gas 17.

[0075] Further, the method for treating combustibles includes a pyrolysis step of pyrolyzing combustibles at a temperature of 350 ° C or more to obtain a pyrolysis gas and a pyrolysis step. Combustion process in which tar and char are burned at a temperature of 500 ° C or more, and melt-burning process in which the pyrolysis gas generated in the pyrolysis process is burned at 1200 ° C or more and the ash accompanying the pyrolysis gas is melted Combustion process power: a heat recovery process that recovers sensible heat until the discharged combustion gas becomes 450 ° C or less, and a dust collection process that collects ash contained in the combustion gas downstream of the heat recovery process. The ash collected in the dust collecting step is supplied to the melting and burning step to be melted.

[0076] In such a method for treating combustibles, since the combustion gas discharged from the combustion step does not pass through a melting furnace, the properties, shape, and size of the ash particles in the combustion gas are as follows. Conventional fluidized bed incinerator power Same as the properties, shape and size of ash particles in the discharged combustion gas, but adheres to the heat transfer surface of heat recovery equipment even if heat recovery is performed in the heat recovery process where the particle size is large Then There is no danger of inviting.

[0077] Further, according to the above-described method for treating combustibles, both the pyrolysis step and the combustion step are performed in a fluidized bed furnace, and the amount of heat required for the pyrolysis in the pyrolysis step is determined by the fluidized bed in which the combustion step is performed. It is characterized by being supplied by the sensible heat of the fluid medium of the furnace.

[0078] As described above, the amount of heat required for the thermal decomposition in the thermal decomposition step is covered by the sensible heat of the fluidized medium of the fluidized bed furnace in which the combustion step is performed. Running costs and initial costs, which do not require a generator or the like, are reduced.

[0079] In the method for treating combustibles, the pyrolysis step is maintained at 650 ° C or lower, preferably 600 ° C or lower, more preferably 550 ° C or lower, and the temperature of the combustion step is 900 ° C or lower. Preferably, the temperature is maintained at 800 ° C or lower, more preferably 700 ° C or lower.

[0080] As described above, in order to stably pyrolyze gas into combustibles such as garbage with little fluctuation, it is preferable to carry out at a low temperature of 650 ° C or less, and to carry out at 550 ° C or less. Thereby, more stable pyrolysis gasification can be performed. In addition, in the pyrolysis step, in order to stably burn combustible materials such as garbage with little fluctuation, it is preferable to maintain the low temperature at a low temperature of 700 ° C. or lower. At a high temperature of 900 ° C or more, there is a problem particularly in heat resistance of a metal portion such as a dispersion nozzle. The lower temperature limit of the pyrolysis process differs depending on the type of combustibles. When the combustibles are, for example, only biomass, the decomposition temperature of general lignin is 280 ° C. Therefore, the temperature is preferably higher than 300 ° C. In addition, when plastic is contained in combustibles, the decomposition temperature of general high-density polyethylene HDPE is 390 ° C, so it is preferable to set the temperature higher than 400 ° C.

[0081] Further, a combustible material processing apparatus is provided with a pyrolysis chamber for pyrolyzing the combustible material at a temperature of 350 ° C or higher to obtain a fuel and a pyrolysis gas, and an unpyrolyzed product generated from the pyrolysis chamber. , Tar and charcoal are burned at a temperature of 500 ° C or more, and a pyrolysis gas generated in the pyrolysis chamber is burned at 1200 ° C or more and ash that accompanies the pyrolysis gas is melted. A furnace, a heat recovery device for recovering sensible heat of the combustion gas discharged from the combustion chamber to 450 ° C. or less, and a collector for collecting ash contained in the combustion gas downstream of the heat recovery device. And a dust device, wherein the ash collected by the dust collector is supplied to the melting furnace to be melted. [0082] As described above, since the combustion gas discharged from the combustion chamber does not pass through the melting furnace, the properties, shape, and size of the ash particles in the combustion gas are discharged from the conventional fluidized bed incinerator. Similar to the properties, shape, and size of the ash particles in the combustion gas, even if heat is recovered by a heat recovery device with a large particle size, there is no danger of adhesion to the heat transfer surface and causing trouble. In addition, since the ash collected by the dust collector is supplied to the melting furnace downstream of the heat recovery unit, for example, low-boiling substances and metal salts that have become fine particles by using a cyclone in the dust collector are collected and circulated. Slag conversion rate can be improved.

[0083] In the above combustible material processing apparatus, the pyrolysis chamber and the combustion chamber are both constituted by a fluidized bed furnace.

[0084] As described above, since the pyrolysis chamber and the combustion chamber are both constituted by a fluidized-bed furnace, stable pyrolysis gasification of combustible materials in the pyrolysis chamber becomes possible, and the combustion chamber is incinerated by a fluidized-bed incinerator. The ash particles in the combustion gas discharged from a conventional fluidized bed incinerator have the same properties, shape and size as the ash particles in the combustion gas discharged from the conventional fluidized bed incinerator. However, there is no danger of adhesion to the heat transfer surface of the equipment used and causing trouble.

[0085] In the above combustible material processing apparatus, the fluidized medium of the fluidized bed furnace constituting the thermal decomposition chamber and the fluidized medium of the fluidized bed furnace constituting the combustion chamber are circulated.

[0086] As described above, since the fluidized media of the fluidized bed furnace constituting the thermal decomposition chamber and the fluidized bed furnace constituting the combustion chamber are circulating, the non-pyrolyzed product remaining in the fluidized bed of the thermal decomposition chamber, The tar and char move with the flowing medium into the combustion chamber, where the unpyrolyzed product, tar and char are burned. The fluidized medium in the fluidized bed of the combustion chamber heated by the combustion moves to the thermal decomposition chamber and is used as heat of gasification.

[0087] Further, in the above combustible material processing apparatus, steam, carbon dioxide gas, nitrogen gas, and combustion exhaust gas are used as fluidizing gas of the fluidized bed of the fluidized bed furnace constituting the thermal decomposition chamber. You.

[0088] As described above, by using steam, carbon dioxide gas, and nitrogen gas as the fluidizing gas of the fluidized bed of the fluidized bed furnace constituting the thermal decomposition chamber, the portion of the combustible material supplied to the thermal decomposition chamber Since there is no heating of the fluidized medium due to this combustion, the heat of the fluidized medium from the combustion chamber can be effectively absorbed. In addition, since there is no partial combustion of combustibles in the pyrolysis chamber, A gas with a high calorific value is obtained from the pyrolysis chamber where the combustion gas is not contained in the gas, and this gas is supplied to the melting furnace, and the calorific value is low, for example, 6-7 Mj / kg. Even if it does, it is possible to burn at a high temperature of 1200 ° C or more without supplying auxiliary fuel in the melting furnace, and it is possible to melt ash.

The above example is an embodiment of the present invention, and the invention described in each claim is not limited to the scope of the same technical idea as the invention described in each claim. Deformation is possible within.

Brief Description of Drawings

FIG. 1 is a view showing a process flow of a conventional combustible material processing apparatus.

FIG. 2 is a view showing a process flow of a conventional combustible material processing apparatus.

FIG. 3 is a view showing a process flow of a combustible material processing apparatus according to the present invention.

FIG. 4 is a view showing a process flow of a combustible material processing apparatus according to the present invention.

FIG. 5 is a view showing a configuration example of an integrated fluidized-bed gasification furnace used in the combustible material processing apparatus according to the present invention.

FIG. 6 is a view showing a configuration example of a two-tower type fluidized-bed gasification furnace used in the apparatus for treating combustibles according to the present invention.

FIG. 7 is a diagram showing a configuration example of a melting furnace used in the combustible material processing apparatus according to the present invention.

FIG. 8 is a view showing a process flow of a combustible material processing apparatus according to the present invention.

Explanation of symbols

[0091] 1 Gasifier

2 melting furnace

3 boilers

4 Heat recovery equipment

5 Dust collector

6 gas cooling tower

7 bug filter

8 Induction blower

9 catalytic denitration tower chimney

Ash

Bag filter (solid separator) Ash

Activated carbon

boiler

Scrubber

Raw material gas

Pyrolysis chamber

Combustion chamber

Heat recovery room

Partition wall

Aperture

In-layer heat transfer tube

Lower opening

Partition wall

Lower opening

Fluidizing gas

Combustibles supply device Pyrolysis fluidized bed furnace

Combustion fluidized bed furnace

Inclined tube

Fluidizing gas

Fluidizing gas Primary combustion chamber Secondary combustion chamber Tertiary combustion chamber Combustion gas Molten slag Slag ίNon-exit

Claims

The scope of the claims

[1] recovering heat from the first gas with many large particles;

Recovering heat by mixing the first gas from which the heat has been recovered with a second gas accompanied by a large number of particles having a small particle size;

Heat recovery method.

[2] The first gas is composed of a gas containing particles generated in the fluidized bed furnace by supplying combustibles to the fluidized bed furnace,

The second gas comprises a gas accompanied by particles obtained by introducing a gas generated in the fluidized-bed furnace into a melting furnace to melt ash.

The heat recovery method according to claim 1.

[3] a step of pyrolyzing the combustibles in the fluidized bed furnace to obtain gas and gas;

Burning said char in said furnace;

The heat recovery method according to claim 2.

[4] burning the char in a combustion chamber;

Flowing the fluidized medium from the combustion chamber to a pyrolysis chamber for pyrolyzing the combustibles;

4. The heat recovery method according to claim 3.

[5] a step of mixing the first gas and the second gas;

Cooling the mixed gas below 450 ° C;

Separating a solid content in the cooled gas by a dust collector;

The heat recovery method according to any one of claims 2 to 4, further comprising: introducing the separated solid content into the melting furnace and melting the solid content.

[6] a step of generating a first gas and a second gas containing particles in a fluidized-bed gasifier; a step of introducing the first gas from the fluidized-bed gasifier into a heat recovery device; A step of performing heat exchange between the introduced gas and the heat-receiving fluid to recover heat; and a step of introducing a second gas from the fluidized-bed gasification furnace into a melting furnace to melt ash in the particles. When;

Introducing a gas in which the ash is melted into the heat recovery device; How to treat combustibles.

[7] a step of generating a first gas and a second gas containing particles in a fluidized-bed gasification furnace; a step of introducing the first gas from the fluidized-bed gasification furnace into a heat recovery device; A step of performing heat exchange between the introduced gas and the heat-receiving fluid to recover heat; and a step of introducing a second gas from the fluidized-bed gasification furnace into a melting furnace to melt ash in the particles. When;

Introducing the gas in which the ash has been melted into a heat recovery device into which the first gas has been introduced;

How to treat combustibles.

[8] recovering heat of the first gas and the second gas with a heat recovery device, and cooling the gas to 450 ° C or less;

The method according to claim 6 or 7, further comprising: a step of separating solids in the first gas and the second gas by a dust collector; and a step of introducing the separated solids into the melting furnace and melting the solids. The method for treating combustible materials described in the above.

[9] a first inlet for introducing a first gas having a large particle diameter and a large amount of particles;

A second inlet that is located downstream of the first inlet with respect to a flow side of the gas introduced from the first inlet and that introduces a second gas containing many particles having a small particle diameter; An outlet for discharging gas after recovering heat;

A heat transfer surface for recovering heat by exchanging heat between the gas introduced from the first and second inlets and the heat receiving fluid;

Heat recovery device.

[10] The first gas is a gas generated by supplying a combustible material to a fluidized bed furnace and producing the gas in the fluidized bed furnace.

The heat recovery apparatus according to claim 9, wherein the second gas is a gas obtained by introducing a gas generated in the fluidized-bed furnace into a melting furnace to melt ash contained in the gas. .

[11] After mixing the first gas and the second gas, the mixture is cooled to 450 ° C. or less, and then the solid content in the mixed gas is separated by a dust collector, and the separated solid content is melted. Configured to be introduced into the furnace and melted; The heat recovery device according to claim 10.

[12] A fluidized-bed gasi furnace for gasifying combustibles to generate a first gas and a second gas containing particles;

A heat recovery device for recovering heat by introducing the first gas generated in the fluidized bed gasifier and exchanging heat with a heat receiving fluid;

A melting furnace for introducing a second gas generated in the fluidized-bed gasification furnace to melt ash; and a melting furnace power for discharging the discharged gas together with particles further generated in the melting furnace. A gas introduction passage for introducing the gas into the air;

Combustible material processing equipment.

[13] A fluidized-bed gasifier which gasifies combustibles to generate a first gas and a second gas containing particles;

A melting furnace for introducing a second gas generated in the fluidized-bed gasification furnace to melt ash; and a gas discharged from the melting furnace, together with particles further generated in the melting furnace, the first gas. A gas introduction passage for introducing into a heat recovery apparatus into which a gas is introduced;

Combustible material processing equipment.

[14] The fluidized-bed gasifier includes a pyrolysis chamber that pyrolyzes combustibles to generate the second gas, a combustion chamber that burns fuel and generates the first gas, A flow path for moving fluidized medium from the chamber to the pyrolysis chamber;

14. The apparatus for treating combustible materials according to claim 12 or 13.

[15] a flow path for introducing the second gas from the pyrolysis chamber into the melting furnace;

The apparatus for treating combustible matter according to claim 14, further comprising: a flow path for introducing a first gas from the combustion chamber into the heat recovery device.

[16] The combustible material processing apparatus according to any one of claims 12 to 15, wherein the heat recovery apparatus is a waste heat boiler.

[17] After mixing the first gas and the second gas, the mixture is cooled to 450 ° C. or lower, and then the solid content in the mixed gas is separated by a dust collector, and the separated solid content is melted. Introduce into furnace and melt Configured to cause;

An apparatus for treating combustible materials according to any one of claims 12 to 16.

A fluidized-bed gasifier for gasifying combustibles to produce a first gas and a second gas containing particles;

A solid separator for collecting the particles in the first gas generated in the fluidized bed gasifier;

A melting furnace that burns the second gas generated in the fluidized-bed gasification furnace, melts the particles collected by the solid separator, and generates a flammable gas; apparatus.