JP2011099066A - Circulating fluidized bed type gasification method and apparatus therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a circulating fluidized bed type gasification method, by which the retention time of a raw material in a gasification oven can be elongated to ensure a gasification reaction time, and the performance of the gasification can be improved, without enlarging the gasification oven in one direction and without arranging a partition plate in the gasification oven heated at a high temperature, and to provide a circulating fluidized bed type gasification apparatus. <P>SOLUTION: The circulating fluidized bed type gasification apparatus is characterized by opening the charging port 9a of a raw material-charging pipe 9 connected to one side of the gasification oven 2 at a place above the inner fluidized bed 1 of the gasification oven 2 and arranging the lower end opening 7b of a medium flow-down pipe 7 at least on the flow-down side adjacent to the charging port 9a of the raw material-charging pipe 9. <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 via 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 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 is not required to lengthen the gasification furnace in one direction, and without providing a partition plate inside the gasification furnace that becomes high temperature, the residence time of the raw material inside the gasification furnace It is intended to provide a circulating fluidized bed type gasification method and apparatus that can secure a gasification reaction time by lengthening the gas flow and can improve gasification performance.

The present invention forms a fluidized bed of a fluidized medium by a gasifier flowing gas in a gasifier and gasifies a raw material charged into one side of the gasifier to perform gasification gas and combustible solids. The gasification gas generated in the gasification furnace is taken out, and the combustible solid content generated in the gasification furnace is introduced into the combustion furnace from the other side of the gasification furnace together with the fluidized medium, and the combustion is performed. In the furnace, a fluidized bed is formed by a combustion furnace fluidizing gas and the combustible solid content is burned, and the fluidized medium is separated from the combustion exhaust gas of the combustion furnace by a medium separator, and the separated fluidized medium is converted into the gasification furnace. In the circulating fluidized bed gasification method to return to
By introducing the fluid medium separated by the medium separator at least downstream adjacent to the raw material charging position on one side of the gasification furnace, the fluid medium flows inside the gasification furnace. The present invention relates to a circulating fluidized bed type gasification method characterized in that a raw material is entrained in a flow submerged in a bed.

The present invention also provides a gasification furnace that forms a fluidized bed of a fluidized medium with a gasification furnace fluidizing gas and gasifies a raw material charged to one side to generate a gasification gas and a combustible solid content. A combustion furnace in which the combustible solid content generated in the gasification furnace is introduced from the other side of the gasification furnace together with a fluidized medium, and a fluidized bed is formed by the combustion furnace flow gas to burn the combustible solid content. And a circulating fluidized bed type gasifier comprising a medium separator for separating the fluid medium from the combustion exhaust gas of the combustion furnace and returning the separated fluid medium to the gasifier,
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 gasification furnace and for introducing the fluidized medium separated by the medium separation device into the gasification furnace at least downstream adjacent to the input position of the raw material from the raw material input pipe; The present invention relates to a circulating fluidized bed type gasifier.

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

  Inside the gasification furnace, the horizontal moving speed of the fluidized medium in the surface layer of the fluidized bed is faster than the bottom part, and the raw material such as coal has a specific gravity smaller than that of the fluidized medium such as silica sand, Although it is easy to ride the flow of the fluidized medium, the raw material input from the raw material input pipe to the side of the gasification furnace flows into the fluidized bed inside the gasification furnace of the fluidized medium input from the medium flow down pipe. Since it is accompanied, the raw material does not go out from the upper part of the other side of the gasification furnace in a short time, the residence time of the raw material in the gasification furnace becomes long, and the gasification reaction of the raw material It is possible to secure time, and it is not necessary to increase the length in the direction from one side of the gasification furnace to the other side, which reduces production costs and repair costs, and requires a larger installation space. There is no gasification and gasification becomes high Interior need not be disposed partition plates.

  According to the circulating fluidized bed gasification method and apparatus of the present invention, the inside of the gasification furnace can be formed without increasing the length of the gasification furnace in one direction and without providing a partition plate inside the gasification furnace that becomes high temperature. It is possible to increase the residence time of the raw material at the time and to secure the gasification reaction time, and to achieve an excellent effect that the gasification performance can be improved.

1 is an overall schematic configuration diagram showing an embodiment of the present invention. It is the II-II cross-section equivalent figure of FIG. 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.

  1 and 2 show an embodiment of the present invention. In the figure, the same reference numerals as those in FIG. 3 denote the same components, and the basic configuration is the same as that of the conventional one shown in FIG. However, the feature of this embodiment is that, as shown in FIG. 1 and FIG. 2, the flow inside the gasifier 2 is made through the inlet 9 a of the raw material inlet pipe 9 connected to one side of the gasifier 2. The lower end opening 7b of the medium flow down pipe 7 is disposed at least on the downstream side adjacent to the input port 9a of the raw material input pipe 9 while being opened above the layer 1.

  In the case of this embodiment, the lower end opening 7b of the medium flow pipe 7 has a width W on the inner surface of the gasification furnace 2 (perpendicular to the longitudinal direction from one side of the gasification furnace 2 to the other side, as shown in FIG. In the shape of an ellipse substantially equal to the horizontal dimension in the horizontal direction).

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

  Inside the gasification furnace 2, the horizontal moving speed of the fluidized 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 that of the fluidized medium such as silica sand. Although it is easy to ride the flow of the fluid medium on the surface layer, the raw material introduced into the gasification furnace 2 from the inlet 9 a of the raw material inlet pipe 9 is input from the lower end opening 7 b of the medium downstream pipe 7. Since the fluidized medium is accompanied by the flow that flows into the fluidized bed 1 inside the gasification furnace 2, the raw material does not go out from the upper part on the other side of the gasification furnace 2 in a short time. The residence time of the raw material in the furnace 2 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 2 to the other side. This reduces production and refurbishment costs, and reduces installation costs. Scan without any need to increase, moreover, it is not necessary to dispose the partition plate within the gasification furnace 2 to be hot.

  In the case of the present embodiment, the lower end opening 7b of the medium flow pipe 7 has an oval shape substantially equal to the width W on the inner surface of the gasification furnace 2 as shown in FIG. It is possible to more reliably suppress the raw material that is moved on the flow side of the fluidized medium in the surface layer of the fluidized bed 1 and moving to the downstream side (other side) of the gasification furnace 2. The shape of the lower end opening 7b of the medium flow pipe 7 is not limited to an ellipse, but may be a circle or a rectangle.

  In this way, the gasification furnace 2 is made longer without increasing the length of the gasification furnace 2 in one direction and without providing a partition plate inside the gasification furnace 2 at a high temperature. The gasification reaction time can be secured, and the gasification performance can be improved.

  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 7a Loop seal part 7b Lower end opening part 8 Medium separator 9 Raw material input pipe 9a Input port

Claims (2)

In the gasification furnace, a fluidized bed of a fluidizing medium is formed with gas for gasification furnace flow to gasify the raw material charged to one side of the gasification furnace to generate gasification gas and combustible solids, 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 other side of the gasification furnace together with the fluidized medium, and the combustion furnace Circulating flow in which a fluidized bed is formed by a fluidizing gas and the combustible solid content is combusted to separate the fluidized medium from the combustion exhaust gas of the combustion furnace with a medium separator and return the separated fluidized medium to the gasification furnace In the layer gasification method,
By introducing the fluid medium separated by the medium separator at least downstream adjacent to the raw material charging position on one side of the gasification furnace, the fluid medium flows inside the gasification furnace. A circulating fluidized bed type gasification method characterized in that a raw material is caused to accompany a flow submerged in a bed. A gasification furnace that forms a fluidized bed of a fluidized medium with gas for flowing the gasifier and gasifies the raw material charged to one side to generate gasified gas and combustible solids, and the gasifier A combustion furnace in which the generated combustible solids are introduced together with a fluid medium from the other side of the gasification furnace, and a fluidized bed is formed by a combustion furnace flow gas to burn the combustible solids; In a circulating fluidized bed type gasifier comprising a medium separator for separating a fluid medium from combustion exhaust gas and returning the separated fluid 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 gasification furnace and for introducing the fluidized medium separated by the medium separation device into the gasification furnace at least downstream adjacent to the input position of the raw material from the raw material input pipe; A circulating fluidized bed gasifier characterized by comprising:

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