JP2011042726A - Circulating fluidized bed type gasification method and apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a circulating fluidized bed type gasification method and apparatus capable of separately performing thermal decomposition and gasification of a material, enhancing the carbon conversion ratio by preventing suppression of a gasification reaction by a thermal decomposition gas and effectively using heat of a combustion exhaust gas. <P>SOLUTION: A flowing medium separated by a medium separation apparatus 8 is returned to a gasification furnace 2 via a thermal decomposition furnace 15, and while the material is heat-exchanged with the combustion exhaust gas in a heat exchanger 14 for thermal decomposition to release a thermal decomposition gas containing a tar, it is fed to the thermal decomposition furnace 15 in which the fluidized bed 15a is formed by an inert gas and is further subjected to thermal decomposition to generate a thermal decomposition gas. The flowing medium containing the material in which the thermal decomposition gas is separated in the thermal decomposition furnace 15 is introduced into the gasification furnace 2, gasification of the material is only performed in the gasification furnace 2, and the flowing medium and an inflammable solid content are introduced into a combustion furnace 5. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a circulating fluidized bed gasification method and apparatus.

  2. Description of the Related Art Conventionally, development of a circulating fluidized bed gasifier that generates a gasification gas using raw materials such as coal, biomass, waste plastic, or various hydrated wastes as fuel has been promoted.

  FIG. 3 shows an example of a conventional circulating fluidized bed type gasifier, and the circulating fluidized bed type gasifier is used for the flow of a gasifier such as water vapor that is charged with the raw material and also serves as a gasifying agent. A gasification furnace 2 for generating a gasified gas and a combustible solid content by gasifying the raw material by forming a fluidized bed 1 of a fluid medium (such as cinnabar) with gas, and the gasification furnace 2 Combustion furnace 5 in which combustible solids are introduced together with a fluid medium through an extraction loop seal tube 3 and fluidized bed 4 is formed by combustion furnace gas such as air or oxygen to burn the combustible solids. And a cyclone provided in the exhaust gas pipe 6 for extracting the combustion exhaust gas from the combustion furnace 5 and separating the fluid medium from the combustion exhaust gas and supplying the separated fluid medium to the gasification furnace 2 through the medium flow pipe 7 And a medium separating device 8 such as It is.

  In FIG. 3, 9 is a raw material charging pipe for charging the raw material into the gasification furnace 2, 10 is a wind box formed at the bottom of the gasification furnace 2, and 11 is gasification introduced into the wind box 10. A diffuser plate 12 having a large number of diffuser nozzles (not shown) for forming a fluidized bed 1 by uniformly blowing a gas for furnace flow into the gasification furnace 2 is formed at the bottom of the combustion furnace 5. The wind box 13 is a diffuser plate having a large number of diffuser nozzles 13a for uniformly blowing the combustion furnace flowing gas introduced into the wind box 12 into the combustion furnace 5 to form the fluidized bed 4. .

  Further, a loop seal portion 7 a is formed in the middle of the medium flow down pipe 7 so that the gasified gas generated in the gasification furnace 2 does not flow backward to the medium separation device 8.

  In the circulating fluidized bed type gasifier as described above, the fluidized bed is formed on the diffuser plate 11 of the wind box 10 by the gasifying furnace flowing gas such as water vapor which also serves as a gasifying agent in the gasifying furnace 2 during normal operation. 1 is formed, and when a raw material such as coal is input from the raw material input pipe 9, the raw material is gasified, and a gasified gas and a combustible solid are generated and generated in the gasification furnace 2. The combustible solid content is extracted together with the fluid medium through the extraction loop seal tube 3, and the combustion furnace 5 in which the fluidized bed 4 is formed on the diffuser plate 13 of the wind box 12 by the combustion furnace flow gas. The combustible solid content is combusted, and the combustion exhaust gas from the combustion furnace 5 is introduced into the medium separation device 8 via the exhaust gas pipe 6. The fluid medium is separated and the Isolated fluidized medium is returned through a medium flow down tube 7 to the gasification furnace 2, it is circulated.

Here, the fluidized medium that has become high in temperature due to the combustion of combustible solids in the combustion furnace 5 is separated together with the combustion exhaust gas through the exhaust gas pipe 6 by the medium separation device 8, and is gasified through the medium flow down pipe 7. By supplying to the furnace 2, the high temperature of the gasification furnace 2 is maintained, and the gas generated by the thermal decomposition of the raw material and its thermal decomposition residue (char) react with the water vapor, thereby causing the water vapor gasification reaction. [C + H ₂ O = H ₂ + CO] and hydrogen conversion reaction [CO + H ₂ O = H ₂ + CO ₂ ] occur, and combustible gasification gas such as H ₂ and CO is generated.

  The gasification gas generated in the gasification furnace 2 is supplied to a chemical plant or a gas turbine after the dust and the like are separated and removed by a medium separation device such as a cyclone (not shown), while the medium separation device The combustion exhaust gas from which the fluid medium is separated in 8 is sent to the exhaust gas treatment device.

  Incidentally, when the heat quantity during normal operation in the circulating fluidized bed gasifier is insufficient, that is, when the gasifier 2 cannot obtain sufficient heat for gasification of the raw material, the gasifier A fuel such as coal that is the same as the raw material supplied to 2 is supplied to the combustion furnace 5 in an auxiliary manner and burned to make up for the insufficient heat. In addition, during the circulation preheating operation in the stage before reaching the normal operation in the circulating fluidized bed gasifier, the raw material is not charged into the gasification furnace 2, and water vapor is supplied from the bottom of the gasification furnace 2. Instead, with the flow air supplied, the fuel such as coal is charged into the combustion furnace 5 for preheating and combusted, and the flow becomes high as the fuel burns in the combustion furnace 5. The medium is separated together with the combustion exhaust gas by the medium separation device 8 through the exhaust gas pipe 6 and supplied to the gasification furnace 2 through the medium flow pipe 7, whereby circulation preheating of the circulating fluidized bed gasification device is performed. It has come to be.

  Examples of the general technical level related to the circulating fluidized bed gasifier as described above include Patent Documents 1, 2, and 3.

JP-A-3-287695 JP 2006-265454 A JP 2007-112872 A

  By the way, in the case of the circulating fluidized bed type gasifier as described above, in the low-temperature steam gasification reaction (700 to 900 [° C.]) of organic raw materials such as coal and biomass, combustible solid content is generated by pyrolysis gas containing tar. Therefore, it is desired to separate the pyrolysis gas from the steam gasification reaction.

  Incidentally, if the steam gasification reaction of the pyrolysis residue (char) is hindered, a longer reaction time is required. Therefore, in order to obtain the same amount of gasification gas as a product, the gasification furnace It is necessary to increase the length of 2 and increase the amount of gasification furnace flow gas such as water vapor that also serves as a gasifying agent.

  Further, the combustion exhaust gas from which the fluid medium has been separated by the medium separation device 8 is simply sent to the exhaust gas treatment device, and it cannot be said that heat recovery is sufficiently performed.

  And although the thermal decomposition gasification apparatus using a fluidized bed is disclosed by the said patent documents 1, 2, and 3, there existed the following problems.

  In the coal pyrolysis and gasification method disclosed in Patent Document 1, since only pulverized coal can be used as fuel, organic materials such as biomass cannot be used, and some unreacted char is gasified. Since it is discharged from the bottom of the furnace, the carbon conversion rate may be lowered.

  In the circulating fluidized gasification furnace disclosed in Patent Document 2, since the gasified gas is discharged from the cyclone outlet at the top of the downcomer that is the gasification section, the circulation speed of the fluidized sand that is the heat medium is high. While lowering and increasing heat dissipation, the lack of heat is compensated by the hot stove burner, which may increase the cost.

  In the fuel gasification facility disclosed in Patent Document 3, since the pyrolysis gas is not separated from the gasification reaction, the gasification reaction may be hindered and the carbon conversion rate may be lowered.

  In view of such circumstances, the present invention can separate the pyrolysis and gasification of the raw material, can prevent the gasification reaction by the pyrolysis gas, improve the carbon conversion rate, and It is an object of the present invention to provide a circulating fluidized bed gasification method and apparatus capable of effectively utilizing heat.

The present invention forms a fluidized bed of a fluidized medium by a gasification furnace fluidizing gas that also serves as a gasifying agent in a gasification furnace to gasify a raw material to generate a gasification gas and a combustible solid content. While the gasification gas generated in the gasification furnace is taken out, the combustible solid content generated in the gasification furnace is introduced into the combustion furnace from the gasification furnace together with the fluidized medium, and flows in the combustion furnace with the gas for flowing the combustion furnace. A circulating fluidized bed gasification method in which a fluidized medium is separated from a combustion exhaust gas of the combustion furnace by a medium separation device and the separated fluidized medium is returned to the gasification furnace while forming a layer and burning the combustible solid content. In
Returning the fluid medium separated by the medium separator to the gasification furnace via a pyrolysis furnace,
The raw material is heat-exchanged with the combustion exhaust gas by a heat decomposition heat exchanger to release a pyrolysis gas containing tar, and is put into a pyrolysis furnace in which a fluidized bed is formed with an inert gas and further pyrolyzed. To generate pyrolysis gas,
A fluid medium containing a raw material from which pyrolysis gas has been separated in the pyrolysis furnace is introduced into the gasification furnace, and only the raw material is gasified in the gasification furnace, and the fluid medium and combustible solids are obtained. The present invention relates to a circulating fluidized bed gasification method which is introduced into the combustion furnace.

Further, the present invention forms a fluidized bed of a fluidized medium by a gasification furnace fluidizing gas that also serves as a gasifying agent in a gasification furnace to gasify the raw material to produce a gasification gas and a combustible solid content, While taking out the gasification gas generated in the gasification furnace, the combustible solid content generated in the gasification furnace is introduced into the combustion furnace from the gasification furnace together with the fluidized medium, and the combustion furnace flowing gas in the combustion furnace A circulating fluidized bed gas for separating the fluidized medium from the combustion exhaust gas of the combustion furnace with a medium separation device and returning the separated fluidized medium to the gasification furnace while forming a fluidized bed by burning the combustible solids In the conversion method,
Returning the fluid medium separated by the medium separator to the gasification furnace via a pyrolysis furnace,
The raw material is put into a pyrolysis furnace in which a fluidized bed is formed with an inert gas, pyrolyzed to generate pyrolysis gas, and the pyrolysis gas is heat exchanged with the combustion exhaust gas in a tar decomposition heat exchanger. Break down tar,
A fluid medium containing a raw material from which pyrolysis gas has been separated in the pyrolysis furnace is introduced into the gasification furnace, and only the raw material is gasified in the gasification furnace, and the fluid medium and combustible solids are obtained. The present invention relates to a circulating fluidized bed gasification method which is introduced into the combustion furnace.

On the other hand, the present invention comprises a gasification furnace that forms a fluidized bed of a fluidized medium by a gasification fluidizing gas that also serves as a gasifying agent to gasify a raw material to generate gasified gas and combustible solids, Combustion furnace in which combustible solids generated in the gasification furnace are introduced together with a fluidized medium and a fluidized bed is formed by a combustion furnace flow gas to burn the combustible solids, and combustion exhaust gas from the combustion furnace In a circulating fluidized bed type gasifier comprising a medium separator for separating the fluid medium from the medium and returning the separated fluid medium to the gasification furnace,
A heat exchanger for thermal decomposition, in which the raw material is subjected to heat exchange with the combustion exhaust gas to release pyrolysis gas containing tar;
The fluidized medium separated by the medium separator is introduced, a fluidized bed is formed with an inert gas, and the raw material that has passed through the heat exchanger for thermal decomposition is further pyrolyzed in the fluidized bed to generate a pyrolytic gas. And a pyrolysis furnace for introducing the raw material from which the pyrolysis gas has been separated and the fluidized medium to the gasification furnace.

  In the circulating fluidized bed type gasifier, the inner pipe and the outer pipe are arranged concentrically, and the raw material is introduced into the inner pipe and from the combustion furnace separated by the medium separator. The heat exchanger for thermal decomposition can be constituted by a double pipe heat exchanger in which combustion exhaust gas is introduced between the inner pipe and the outer pipe.

The present invention also includes a gasification furnace that forms a fluidized bed of a fluidized medium by a gasification fluidizing gas that also serves as a gasifying agent to gasify a raw material to generate a gasified gas and a combustible solid. Combustion furnace in which combustible solids generated in the gasification furnace are introduced together with a fluidized medium and a fluidized bed is formed by a combustion furnace flow gas to burn the combustible solids, and combustion exhaust gas from the combustion furnace In a circulating fluidized bed type gasifier comprising a medium separator for separating the fluid medium from the medium and returning the separated fluid medium to the gasification furnace,
The fluidized medium separated by the medium separator is introduced, a fluidized bed is formed with an inert gas, the raw material charged in the fluidized bed is pyrolyzed to generate a pyrolyzed gas, and the pyrolyzed gas is separated. A pyrolysis furnace for guiding the raw material and the fluidized medium to the gasification furnace;
The present invention relates to a circulating fluidized bed gasifier comprising a tar decomposition heat exchanger that decomposes tar by heat-exchanging pyrolysis gas generated in the pyrolysis furnace with the combustion exhaust gas. .

  In the circulating fluidized bed type gasifier, an inner tube and an outer tube are arranged concentrically, and pyrolysis gas generated in the pyrolysis furnace is introduced into the inner tube, and the medium separation is performed. The tar decomposition heat exchanger can be configured by a double pipe heat exchanger in which the flue gas from the combustion furnace separated by the apparatus is introduced between the inner pipe and the outer pipe.

  According to the circulating fluidized bed gasification method and apparatus of the present invention, the pyrolysis and gasification of the raw material can be performed separately, and the carbon conversion rate is improved by preventing the gasification reaction by the pyrolysis gas. And an excellent effect that the heat of the combustion exhaust gas can be effectively utilized.

1 is an overall schematic configuration diagram showing a first embodiment of the present invention. It is a whole schematic block diagram which shows the 2nd Example of this invention. It is a whole schematic block diagram which shows an example of the conventional circulating fluidized-bed type gasifier.

  Embodiments of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 shows a first embodiment of the present invention. In the figure, the same reference numerals as those in FIG. 3 denote the same parts, and the basic configuration is the same as the conventional one shown in FIG. However, the feature of the first embodiment is that, as shown in FIG. 1, the raw material is subjected to heat exchange with the combustion exhaust gas from the combustion furnace 5 separated by the medium separation device 8 to produce pyrolysis gas containing tar. A heat exchanger 14 for pyrolysis to be discharged;
The fluid medium separated by the medium separator 8 is introduced by the medium flow pipe 7, and a fluidized bed 15a is formed by an inert gas. The raw material that has passed through the thermal decomposition heat exchanger 14 is further passed through the fluidized bed 15a. A pyrolysis furnace 15 is additionally provided which generates pyrolysis gas by pyrolysis and guides the raw material from which the pyrolysis gas has been separated and the fluidized medium to the gasification furnace 2 through the overflow pipe 16.

  In the case of the first embodiment, the thermal decomposition heat exchanger 14 has an inner tube 14a and an outer tube 14b arranged concentrically, and a raw material is introduced into the inner tube 14a. Combustion exhaust gas from the combustion furnace 5 separated by the medium separator 8 is constituted by a double tube heat exchanger in which the flue gas is introduced between the inner tube 14a and the outer tube 14b. The thermal decomposition heat exchanger 14 is kept warm by providing a heat storage material (not shown) around the double pipe.

  In addition, a wind box 17 similar to the gasification furnace 2 is formed at the bottom of the pyrolysis furnace 15 and an inert gas such as nitrogen introduced into the wind box 17 is uniformly introduced into the pyrolysis furnace 15. A diffuser plate 18 having a large number of diffuser nozzles (not shown) for forming a fluidized bed 15a by being blown into the thermal decomposition furnace 15 is provided, and the thermal decomposition heat exchanger 14 is provided at the side of the thermal decomposition furnace 15. A raw material input pipe 9 for supplying the passed raw material is connected.

  Next, the operation of the first embodiment will be described.

  The fluid medium separated by the medium separator 8 is introduced into the pyrolysis furnace 15 by the medium flow down pipe 7 and returned to the gasification furnace 2 from the fluidized bed 15a of the pyrolysis furnace 15 through the overflow pipe 16. It becomes.

  At the same time, the raw material is introduced into the inner pipe 14a of the thermal decomposition heat exchanger 14 in which the combustion exhaust gas from the combustion furnace 5 separated by the medium separator 8 is introduced between the inner pipe 14a and the outer pipe 14b. In the pyrolysis heat exchanger 14, the heat exchange with the combustion exhaust gas from the combustion furnace 5 separated by the medium separation device 8 exchanges heat to release the pyrolysis gas containing tar, and as a combustible solid content. The pyrolysis residue (char) is introduced into the pyrolysis furnace 15 from the raw material input tube 9. The combustion exhaust gas heat-recovered by exchanging heat with the raw material is sent to an exhaust gas treatment device.

  Here, in the pyrolysis furnace 15, a fluidized bed 15 a is introduced by an inert gas such as nitrogen introduced into the wind box 17 and blown out from a number of diffuser nozzles (not shown) of the diffuser plate 18. The formed raw material containing the pyrolysis residue (char) as the combustible solid content introduced into the pyrolysis furnace 15 from the raw material input pipe 9 is further pyrolyzed to generate pyrolysis gas.

  The fluid medium containing the raw material from which the pyrolysis gas has been separated in the pyrolysis furnace 15 is introduced into the gasification furnace 2 through the overflow pipe 16, and only the raw material is gasified in the gasification furnace 2. The fluid medium and the combustible solid content (gasification residue containing char) are introduced into the combustion furnace 5 through the extraction loop seal pipe 3, and the fluid medium is burned by the combustion of the combustible solid content in the combustion furnace 5. The fluidized medium is heated and circulated.

  The pyrolysis furnace 15 also serves to seal the gasification gas and the pyrolysis gas. In addition, the pyrolysis gas can be used as an auxiliary fuel for the combustion furnace 5 (or a steam generator not shown).

  As a result, even when the gasification furnace flowing gas that also serves as the gasifying agent is steam, the pyrolysis gas containing tar is introduced into the gasification furnace 2 after being separated from the raw material in the pyrolysis furnace 15. Therefore, in the gasification furnace 2, it is possible to avoid the steam gasification reaction of the pyrolysis residue (char) as combustible solid content by the pyrolysis gas, and to increase the carbon conversion rate. . Moreover, the heat of the combustion exhaust gas from which the fluid medium has been separated by the medium separation device 8 is effectively utilized for the thermal decomposition of the raw material.

  Thus, the pyrolysis and gasification of the raw material can be performed separately, the gasification reaction by the pyrolysis gas can be prevented, the carbon conversion rate can be improved, and the heat of the combustion exhaust gas can be effectively utilized.

FIG. 2 shows a second embodiment of the present invention. In the figure, the same reference numerals as those in FIG. 3 denote the same parts, and the basic configuration is the same as the conventional one shown in FIG. However, the second embodiment is characterized in that, as shown in FIG. 2, the fluid medium separated by the medium separator 8 is introduced by the medium flow down pipe 7, introduced into the wind box 17, and the diffuser plate. A fluidized bed 15a is formed by an inert gas such as nitrogen blown out from a large number of 18 aeration nozzles (not shown), and the raw material introduced from the raw material introduction pipe 9 is thermally decomposed and heated by the fluidized bed 15a. A pyrolysis furnace 15 that generates cracked gas and guides the raw material and the fluidized medium from which the pyrolyzed gas is separated to the gasification furnace 2 through the overflow pipe 16;
And a tar-decomposing heat exchanger 19 for decomposing tar by heat-exchanging the pyrolysis gas generated in the pyrolysis furnace 15 with the combustion exhaust gas from the combustion furnace 5 separated by the medium separator 8. It is in.

  In the case of the second embodiment, the tar decomposition heat exchanger 19 has an inner tube 19a and an outer tube 19b arranged concentrically, and the pyrolysis gas generated in the pyrolysis furnace 15 is contained inside. In addition to being introduced into the pipe 19a, the exhaust gas from the combustion furnace 5 separated by the medium separator 8 is constituted by a double pipe heat exchanger that is introduced between the inner pipe 19a and the outer pipe 19b. It is. The tar-decomposing heat exchanger 19 is kept warm by providing a heat storage material (not shown) around the double pipe.

  Next, the operation of the second embodiment will be described.

  The fluid medium separated by the medium separator 8 is introduced into the pyrolysis furnace 15 by the medium flow down pipe 7 and returned to the gasification furnace 2 from the fluidized bed 15a of the pyrolysis furnace 15 through the overflow pipe 16. It becomes.

  At the same time, the raw material is fed into the pyrolysis furnace 15 from the raw material feed pipe 9. Inside the pyrolysis furnace 15, a large number of diffuser nozzles (not shown) are introduced into the wind box 17 and the diffuser plate 18. The fluidized bed 15a is formed by an inert gas such as nitrogen blown out from the gas), and the raw material charged into the pyrolysis furnace 15 from the raw material charging tube 9 is pyrolyzed to generate pyrolysis gas. A pyrolysis residue (char) is produced as a combustible solid.

  The fluid medium containing the raw material from which the pyrolysis gas has been separated in the pyrolysis furnace 15 is introduced into the gasification furnace 2 through the overflow pipe 16, and only the raw material is gasified in the gasification furnace 2. The fluid medium and the combustible solid content (gasification residue containing char) are introduced into the combustion furnace 5 through the extraction loop seal pipe 3, and the fluid medium is burned by the combustion of the combustible solid content in the combustion furnace 5. The fluidized medium is heated and circulated.

  On the other hand, the pyrolysis gas generated in the pyrolysis furnace 15 is used for tar decomposition in which the combustion exhaust gas from the combustion furnace 5 separated by the medium separator 8 is introduced between the inner pipe 19a and the outer pipe 19b. The tar is decomposed by heat exchange with the combustion exhaust gas from the combustion furnace 5 which is introduced into the inner pipe 19a of the heat exchanger 19 and separated by the medium separation device 8 in the tar decomposition heat exchanger 19. Here, tar in the pyrolysis gas is likely to condense and adsorb, and may adversely affect the piping and equipment in the subsequent stage. However, the pyrolysis gas separated in the pyrolysis furnace 15 is used for tar decomposition. Since tar is decomposed in the heat exchanger 19, it can be used as an auxiliary fuel for the combustion furnace 5 (or a steam generator not shown). The combustion exhaust gas heat-recovered by heat exchange with the pyrolysis gas is sent to an exhaust gas treatment device.

  As in the case of the first embodiment, the pyrolysis furnace 15 also serves to seal the gasification gas and the pyrolysis gas.

  As a result, the pyrolysis gas containing tar was separated from the raw material in the pyrolysis furnace 15 even when the gasification furnace flowing gas that also serves as the gasifying agent was steam, as in the first embodiment. Since it is introduced later into the gasification furnace 2, it is avoided in the gasification furnace 2 that the pyrolysis gas inhibits the steam gasification reaction of the pyrolysis residue (char) as combustible solids. The conversion rate can be increased. Moreover, the heat of the combustion exhaust gas from which the fluid medium has been separated by the medium separation device 8 is effectively utilized for the decomposition of tar contained in the pyrolysis gas.

  Thus, in the second embodiment, as in the case of the first embodiment, the pyrolysis and gasification of the raw material can be performed separately, and the gas conversion reaction by the pyrolysis gas is prevented and the carbon conversion rate is improved. In addition, the heat of the combustion exhaust gas can be effectively used.

  The circulating fluidized-bed gasification method and apparatus of the present invention are not limited to the above-described embodiments, and various modifications can be made without departing from the scope of the present invention.

DESCRIPTION OF SYMBOLS 1 Fluidized bed 2 Gasification furnace 3 Extraction loop seal pipe 4 Fluidized bed 5 Combustion furnace 7 Medium flow-down pipe 8 Medium separator 9 Raw material input pipe 10 Wind box 11 Air diffuser plate 14 Pyrolysis heat exchanger 14a Inner pipe 14b Outside Pipe 15 Pyrolysis furnace 15a Fluidized bed 16 Overflow pipe 17 Wind box 18 Air diffuser plate 19 Heat exchanger for tar decomposition 19a Inner pipe 19b Outer pipe

Claims (6)

A gasification fluid and a combustible solid content are generated by forming a fluidized bed of a fluidized medium by using a gasifying fluid that also serves as a gasifying agent in a gasification furnace, and generating a gasified gas and combustible solids. While taking out the gasified gas, the combustible solid content generated in the gasification furnace is introduced into the combustion furnace from the gasification furnace together with the fluidizing medium, and in the combustion furnace, a fluidized bed is formed by the combustion furnace fluidizing gas. In the circulating fluidized bed gasification method, the fluidized medium is separated from the combustion exhaust gas of the combustion furnace by a medium separator while the combustible solid is burned, and the separated fluidized medium is returned to the gasifier.
Returning the fluid medium separated by the medium separator to the gasification furnace via a pyrolysis furnace,
The raw material is heat-exchanged with the combustion exhaust gas by a heat decomposition heat exchanger to release a pyrolysis gas containing tar, and is put into a pyrolysis furnace in which a fluidized bed is formed with an inert gas and further pyrolyzed. To generate pyrolysis gas,
A fluid medium containing a raw material from which pyrolysis gas has been separated in the pyrolysis furnace is introduced into the gasification furnace, and only the raw material is gasified in the gasification furnace, and the fluid medium and combustible solids are obtained. A circulating fluidized bed gasification method, wherein the gasification method is introduced into the combustion furnace. A gasification fluid and a combustible solid content are generated by forming a fluidized bed of a fluidized medium by using a gasifying fluid that also serves as a gasifying agent in a gasification furnace, and generating a gasified gas and combustible solids. While taking out the gasified gas, the combustible solid content generated in the gasification furnace is introduced into the combustion furnace from the gasification furnace together with the fluidizing medium, and in the combustion furnace, a fluidized bed is formed by the combustion furnace fluidizing gas. In the circulating fluidized bed gasification method, the fluidized medium is separated from the combustion exhaust gas of the combustion furnace by a medium separator while the combustible solid is burned, and the separated fluidized medium is returned to the gasifier.
Returning the fluid medium separated by the medium separator to the gasification furnace via a pyrolysis furnace,
The raw material is put into a pyrolysis furnace in which a fluidized bed is formed with an inert gas, pyrolyzed to generate pyrolysis gas, and the pyrolysis gas is heat exchanged with the combustion exhaust gas in a tar decomposition heat exchanger. Break down tar,
A fluid medium containing a raw material from which pyrolysis gas has been separated in the pyrolysis furnace is introduced into the gasification furnace, and only the raw material is gasified in the gasification furnace, and the fluid medium and combustible solids are obtained. A circulating fluidized bed gasification method, wherein the gasification method is introduced into the combustion furnace. A gasification furnace that also serves as a gasifying agent forms a fluidized bed of a fluidized medium by using a gas for fluidizing the gasifying medium, and gasifies the raw material to generate gasified gas and combustible solids. A combustible solid is introduced together with the fluidized medium, and a fluidized bed is formed by the combustion furnace fluidizing gas to burn the combustible solid, and the fluidized medium is separated from the combustion exhaust gas of the combustion furnace. In a circulating fluidized bed type gasifier comprising a medium separator for returning the separated fluid medium to the gasification furnace,
A heat exchanger for thermal decomposition, in which the raw material is subjected to heat exchange with the combustion exhaust gas to release pyrolysis gas containing tar;
The fluidized medium separated by the medium separator is introduced, a fluidized bed is formed with an inert gas, and the raw material that has passed through the heat exchanger for thermal decomposition is further pyrolyzed in the fluidized bed to generate a pyrolytic gas. And a pyrolysis furnace for guiding the raw material from which the pyrolysis gas has been separated and the fluidized medium to the gasification furnace.   The inner tube and the outer tube are arranged concentrically, and the raw material is introduced into the inner tube, and the combustion exhaust gas from the combustion furnace separated by the medium separator is between the inner tube and the outer tube. The circulating fluidized-bed gasifier according to claim 3, wherein the heat exchanger for thermal decomposition is constituted by a double-pipe heat exchanger introduced into the heat exchanger. A gasification furnace that also serves as a gasifying agent forms a fluidized bed of a fluidized medium by using a gas for fluidizing the gasifying medium, and gasifies the raw material to generate gasified gas and combustible solids. A combustible solid is introduced together with the fluidized medium, and a fluidized bed is formed by the combustion furnace fluidizing gas to burn the combustible solid, and the fluidized medium is separated from the combustion exhaust gas of the combustion furnace. In a circulating fluidized bed type gasifier comprising a medium separator for returning the separated fluid medium to the gasification furnace,
The fluidized medium separated by the medium separator is introduced, a fluidized bed is formed with an inert gas, the raw material charged in the fluidized bed is pyrolyzed to generate a pyrolyzed gas, and the pyrolyzed gas is separated. A pyrolysis furnace for guiding the raw material and the fluidized medium to the gasification furnace;
A circulating fluidized bed type gasifier comprising: a tar decomposition heat exchanger that decomposes tar by thermally exchanging pyrolysis gas generated in the pyrolysis furnace with the combustion exhaust gas.   Combustion exhaust gas from a combustion furnace in which an inner pipe and an outer pipe are arranged concentrically and pyrolysis gas generated in the pyrolysis furnace is introduced into the inner pipe and separated by the medium separator The circulating fluidized bed gasifier according to claim 5, wherein the tar decomposition heat exchanger is constituted by a double pipe heat exchanger introduced between an inner pipe and an outer pipe.

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