JP5509793B2 - Circulating fluidized bed gasifier - Google Patents

Description

  The present invention relates to a circulating fluidized bed gasifier.

  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. 2 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 steam into which the raw material is charged 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 via the medium flow pipe 7 And a medium separating device 8 such as It is.

  In FIG. 2, 9 is a raw material input pipe for introducing 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 having a large number of diffuser nozzles 11a for uniformly blowing the gas for furnace flow into the gasification furnace 2 to form the fluidized bed 1, 12 is a wind box formed at the bottom of the combustion furnace 5, Reference numeral 13 denotes a diffuser plate having a large number of diffuser nozzles 13a for forming the fluidized bed 4 by uniformly blowing the combustion furnace flowing gas introduced into the wind box 12 into the combustion furnace 5.

  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, during normal operation, in the gasifier 2, the fluidized bed is formed on the diffuser plate 11 of the wind box 10 by the gasifier flowing gas such as water vapor that also serves as a gasifying agent. 1 is formed, and when a raw material such as coal is input from the raw material input tube 9, the raw material is gasified to generate a gasified gas and a combustible solid, and is generated in the gasifier 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. In the medium separation device 8, the combustion exhaust gas is discharged from the combustion exhaust gas. 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 being supplied to the furnace 2, the high temperature of the gasification furnace 2 is maintained, and the gas generated by thermal decomposition of the raw material and the residual raw material react with water vapor, thereby causing a water gasification reaction [C + H ₂ O = H ₂ + CO] or hydrogen conversion reaction [CO + H ₂ O = H ₂ + CO ₂ ] occurs, and a combustible gasification gas such as H ₂ or CO is generated.

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

  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.

  For example, Patent Document 1 shows a general technical level related to the circulating fluidized bed type gasifier as described above.

JP 2007-112873 A

  By the way, in the case of the conventional circulating fluidized bed type gasifier as described above, the raw material is supplied from the raw material input pipe 9 to one side (upstream side) inside the gasification furnace 2 and separated by the medium separator 8. The fluidized medium is returned to one side inside the gasification furnace 2 through the medium flow pipe 7, and the fluid medium and combustible solid content inside the gasification furnace 2 are transferred to the other side (downstream side) of the gasification furnace 2. It has a structure in which it is extracted from the connected extraction loop seal tube 3 and introduced into the combustion furnace 5, and the horizontal moving speed of the fluid medium in the surface layer of the fluidized bed 1 is faster than the bottom part. Since the raw material has a specific gravity smaller than that of a fluid medium such as silica sand and is easy to ride the fluid medium flow in the surface layer of the fluidized bed 1, the residence time of the material in the gasification furnace 2 is shortened and the gasification reaction is performed. There was a possibility that time could not be secured and gasification performance would be degraded.

  In order to increase the residence time of the raw material in the gasification furnace 2 and secure the gasification reaction time of the raw material, the length in the direction from one side of the gasification furnace 2 to the other side is increased. Although it is necessary, if the length of the gasification furnace 2 is increased, the production cost and the repair cost increase, and the installation space needs to be widened.

  On the other hand, what is disclosed in Patent Document 1 is that a large number of vertical partition plates are arranged at a required interval between one side and the other side of the gasification furnace, from one side inside the gasification furnace to the other side. It is intended to avoid a decrease in gasification performance by forming a zigzag curved flow path that is bent upward and downward, but arranging a large number of partition plates inside the gasification furnace that becomes high temperature It was very difficult as a real problem, leaving room for improvement.

  In view of such circumstances, the present invention extends the residence time of the raw material inside the gasification furnace without increasing the length of the gasification furnace in one direction and only providing the minimum necessary partition plates. Therefore, it is an object of the present invention to provide a circulating fluidized bed type gasifier capable of securing a gasification reaction time and improving gasification performance.

The present invention relates to a gasification furnace that forms a fluidized bed of a fluidized medium with a gasification fluidizing gas and gasifies a raw material to be input to generate a gasification gas and a combustible solid, and the gasification furnace A combustion furnace in which the combustible solid content generated in step 1 is introduced together with a fluidized medium and a fluidized bed is formed by a combustion furnace fluidizing gas to burn the combustible solid content, and the fluidized medium is removed from the combustion exhaust gas of the combustion furnace. In a circulating fluidized bed type gasifier comprising a medium separator for separating and returning the separated fluidized medium to the gasification furnace,
A raw material input pipe connected to one side of the gasification furnace and charging the raw material into the gasification furnace;
A medium flow pipe connected to one side of the gasifier and returning the fluidized medium separated by the medium separator to the gasifier;
An extraction loop seal pipe connected to the other side of the gasification furnace and extracting the fluid medium and combustible solid content inside the gasification furnace and introducing it into the combustion furnace;
A diffuser plate installed at the bottom of the gasifier and blowing a gas for gasifier flow into the gasifier to form a fluidized bed;
An outlet-side partition plate that is disposed on the other side in the gasification furnace so as to have an outlet-side communication path between the lower end and the diffuser plate, the upper end being positioned higher than the upper surface of the fluidized bed; ,
An injection nozzle disposed on the outlet side partition plate so as to suppress the downward flow of the fluid medium generated in the vicinity of the outlet side partition plate on the side opposite to the outlet space by injecting gas for gasifier flow. The present invention relates to a circulating fluidized bed gasifier.

  According to the above means, the following operation can be obtained.

  In the circulating fluidized bed gasifier as described above, the horizontal moving speed of the fluidized medium in the surface layer of the fluidized bed is faster than the bottom, and the raw material such as coal has a lower specific gravity than the fluidized medium such as silica sand, It is easy to ride the flow of the fluid medium on the surface layer of the layer, but the raw material flows down along the outlet side partition plate, and from the outlet side communication path between the lower end of the outlet side partition plate and the diffuser plate. Through the outlet space, it will be discharged into the extraction loop seal tube, so that the raw material will not go out from the upper part of the other side of the gasification furnace in a short time, and inside the gasification furnace The residence time of the raw material becomes longer, it becomes possible to secure the gasification reaction time of the raw material, and it is not necessary to increase the length in the direction from one side of the gasification furnace to the other side. And renovation costs are reduced, and the installation space needs to be widened No.

  Here, if the outlet side partition plate is simply provided, the descending speed of the fluid medium containing the raw material flowing down along the outlet side partition plate is increased. Since the nozzle is provided, the downflow of the fluid medium generated in the vicinity of the counter-outlet space side of the outlet side partition plate is suppressed by the gasification furnace flow gas injected from the injection nozzle, and the gas inside the gasifier This is effective in further extending the residence time of the raw material, and the gasification of the raw material is further promoted by the gasification furnace flow gas injected from the injection nozzle.

  In the circulating fluidized bed type gasifier, an inlet side partition having an upper end positioned higher than the upper surface of the fluidized bed and having an inlet side communication path between the lower end and the diffuser plate on one side in the gasification furnace. An inlet space is defined by disposing a plate, and the upper portion of the inlet space can be configured to input the raw material from the raw material input pipe and the flowing medium from the medium flow down pipe. The raw material from the raw material input pipe and the fluid medium from the medium flow down pipe are input into the inlet space defined by the inlet side partition plate and pass through the inlet side communication passage at the bottom of the gasification furnace, Therefore, it is more effective in avoiding that the raw material from the raw material input pipe directly rides the flow of the fluid medium on the surface layer of the fluidized bed.

  According to the circulating fluidized bed type gasifier of the present invention, the raw material stays in the gasifier without extending the gasifier in one direction and only by arranging the minimum necessary partition plates. The gasification reaction time can be ensured by lengthening the time, and an excellent effect of improving the gasification performance can be achieved.

1 is an overall schematic configuration diagram showing an embodiment of the present 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 an embodiment of the present invention. In the figure, the same reference numerals as those in FIG. 2 denote the same components, and the basic configuration is the same as the conventional one shown in FIG. As shown in FIG. 1, the present embodiment is characterized in that, on the other side in the gasification furnace 2, the upper end is positioned higher than the upper surface of the fluidized bed 1 and the outlet is disposed between the lower end and the diffuser plate 11. An outlet side partition plate 15 having a side communication passage 14 is provided to define an outlet space 16, and the outlet medium partition plate 15 has a fluid medium generated in the vicinity of the outlet side partition plate 15 in the vicinity of the side opposite to the outlet space 16. An injection nozzle 17 is provided to suppress the downward flow by injecting gas for flowing the gasifier.

  In the case of the present embodiment, an inlet-side partition plate having an upper end positioned higher than the upper surface of the fluidized bed 1 and having an inlet-side communication path 18 between the lower end and the diffuser plate 11 on one side in the gasification furnace 2. 19 is provided to define an inlet space 20, and a raw material from the raw material input pipe 9 and a fluid medium from the medium flow down pipe 7 are input to the upper portion of the inlet space 20.

  In addition, the said exit side partition plate 15 is extended to the other side wall surface of the gasifier 2 from the exit side partition plate main body 15a extended in a perpendicular direction, and the upper end located higher than the fluidized-bed 1 upper surface of this exit side partition plate main body 15a. It is formed of a refractory material composed of a seal portion 15b, and inside the outlet side partition plate body 15a and the seal portion 15b, a flow path for gasification furnace flow gas such as water vapor also serving as a gasifying agent is formed. The gasification furnace flow gas can be supplied to the injection nozzle 17. However, since the gasification furnace 2 and the combustion furnace 5 are connected by the extraction loop seal pipe 3, the seal part 15b in the outlet side partition plate 15 is not necessarily provided, and the outlet side partition plate is not necessarily provided. It goes without saying that only the main body 15a may introduce the gasification furnace flowing gas directly into the outlet side partition plate main body 15a.

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

  In the circulating fluidized bed type gasifier as described above, the horizontal moving speed of the fluid medium in the surface layer of the fluidized bed 1 is faster than the bottom, and the raw material such as coal has a specific gravity smaller than the fluid medium such as silica sand, Although it is easy to ride the flow of the fluid medium on the surface layer of the fluidized bed 1, the raw material flows down along the outlet side partition plate 15, and between the lower end of the outlet side partition plate 15 and the diffuser plate 11. Since the outlet side communication passage 14 passes through the outlet space 16 and is discharged to the extraction loop seal pipe 3, the raw material comes out from the upper part on the other side of the gasification furnace 2 in a short time. And the residence time of the raw material in the gasification furnace 2 becomes longer, it becomes possible to secure the gasification reaction time of the raw material, and the length in the direction from one side of the gasification furnace 2 to the other side is reduced. It does n’t have to be long, which can reduce production and refurbishment costs In, it is no longer necessary to wider installation space.

  Here, if the outlet side partition plate 15 is simply provided, the descending speed of the fluid medium containing the raw material flowing down along the outlet side partition plate 15 is increased. Is provided with an injection nozzle 17, and the downward flow of the fluid medium generated in the vicinity of the outlet side partition plate 15 on the side opposite to the outlet space 16 is suppressed by the gasification furnace flow gas injected from the injection nozzle 17. This is effective in further extending the residence time of the raw material in the gasification furnace 2 and further promotes the gasification of the raw material by the gasification furnace flow gas injected from the injection nozzle 17. .

  Moreover, in the present embodiment, on the one side in the gasification furnace 2, the upper end is positioned higher than the upper surface of the fluidized bed 1 and the inlet side communication path 18 is provided between the lower end and the diffuser plate 11. A partition plate 19 is disposed to define an inlet space 20, and a raw material from the raw material input pipe 9 and a fluid medium from the medium flow-down pipe 7 are input to the upper portion of the inlet space 20. Therefore, the raw material from the raw material input pipe 9 and the flowing medium from the medium flow down pipe 7 are input into the inlet space 20 defined by the inlet side partition plate 19, and the inlet side communication at the bottom of the gasification furnace 2 is performed. Since it passes through the passage 18, it is more effective in avoiding that the raw material from the raw material input pipe 9 directly rides the flow of the fluid medium in the surface layer of the fluidized bed 1.

  In this way, the gasification reaction time can be increased by extending the residence time of the raw material in the gasification furnace 2 without increasing the length of the gasification furnace 2 in one direction and by providing the minimum necessary partition plates. It can be ensured and gasification performance can be improved.

  The circulating fluidized-bed gasifier of the present invention is not limited to the above-described embodiments, and it is needless to say that various changes can be made without departing from the gist 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 14 Outlet side communication path 15 Outlet side partition plate 16 Outlet space 17 Injection nozzle 18 Inlet side Communication passage 19 Entrance side partition plate 20 Entrance space

Claims (2)

A gasification furnace that generates a gasification gas and a combustible solid by gasifying a raw material to be input by forming a fluidized bed of a fluidized medium with a gasification furnace flowing gas, and generated in the gasification furnace A combustion furnace in which combustible solids are introduced together with a fluidized medium and a fluidized bed is formed by a combustion furnace fluidizing gas to burn the combustible solids; and the fluidized medium is separated from the combustion exhaust gas of the combustion furnace and separated In a circulating fluidized bed type gasifier comprising a medium separator for returning the fluidized medium to the gasification furnace,
A raw material input pipe connected to one side of the gasification furnace and charging the raw material into the gasification furnace;
A medium flow pipe connected to one side of the gasifier and returning the fluidized medium separated by the medium separator to the gasifier;
An extraction loop seal pipe connected to the other side of the gasification furnace and extracting the fluid medium and combustible solid content inside the gasification furnace and introducing it into the combustion furnace;
A diffuser plate installed at the bottom of the gasifier and blowing a gas for gasifier flow into the gasifier to form a fluidized bed;
An outlet-side partition plate that is disposed on the other side in the gasification furnace so as to have an outlet-side communication path between the lower end and the diffuser plate, the upper end being positioned higher than the upper surface of the fluidized bed; ,
An injection nozzle disposed on the outlet side partition plate so as to suppress the downward flow of the fluid medium generated in the vicinity of the outlet side partition plate on the side opposite to the outlet space by injecting gas for gasifier flow. Circulating fluidized bed type gasifier.   An inlet side partition plate having an upper end located higher than the upper surface of the fluidized bed and having an inlet side communication path between the lower end and the diffuser plate is disposed on one side in the gasification furnace to define an inlet space. The circulating fluidized bed type gasifier according to claim 1, wherein the raw material from the raw material input pipe and the fluid medium from the medium flow down pipe are supplied to the upper portion of the inlet space.

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