JP2014031929A - Fluid bed gasification device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fluid bed gasification device which can prevent combustible gas from leaking into a bed material circulation channel even with positive pressure in a furnace and barely causes abnormal combustion and generation of a residual product.SOLUTION: A fluid bed gasification device comprises a fluid bed gasification furnace which has a bed material configuring a fluid bed therein and a bed material circulation channel which returns the bed material extracted from a furnace again thereto. The bed material circulation channel communicates a bed material extraction port with a bed material returning port of the fluid bed gasification furnace. The bed material circulation channel has: a transfer mechanism which transfers the bed material extracted through the bed material extraction port toward the bed material returning port; a storage section which stores the bed material transferred by the transfer mechanism; a valve which is installed on the storage section at a side of the bed material returning port; a chute which connects the valve with the bed material returning port; and a controller which controls opening/closing of the valve. The controller controls the opening/closing of the valve so that a height of the bed material stored inside the storage is kept at a predetermined height or higher.

Description

  The present invention relates to a fluidized bed gasification apparatus including a fluidized bed gasification furnace, and more particularly, to a fluidized bed gasification furnace that circulates and reuses a fluidized medium extracted from the gasification furnace. The present invention relates to a floor gasifier.

  2. Description of the Related Art Conventionally, a fluidized bed gasifier having a fluidized bed gasification furnace (sometimes referred to as a “fluidized bed carbonization furnace”) is known as an apparatus for treating waste such as municipal waste.

  Here, the fluidized bed gasification furnace has a fluidized bed formed by fluidizing a fluid medium such as sand in the furnace. In a fluidized bed gasifier, the combustible waste introduced into the furnace from the waste inlet is thermally decomposed (partially combusted) in a low oxygen concentration atmosphere. It is converted into a combustible pyrolysis gas containing carbon oxide or the like (hereinafter referred to as “combustible gas”) and a pyrolysis residue (for example, incombustible material, carbide, ash, etc.). Therefore, if a fluidized bed gasifier equipped with a fluidized bed gasifier is used, the volume of waste can be reduced, and the combustible gas generated during thermal decomposition of the waste can be recovered and reused.

  In the fluidized bed gasifier having the conventional fluidized bed type gasifier, the fluid medium containing incombustible material such as metal is extracted from the furnace, and the incombustible material is separated by using means such as classification, and then extracted. The fluidized medium is reused while removing incombustible substances from the fluidized bed by providing a fluidized medium circulation passage that returns the fluidized medium back into the furnace (that is, circulating the fluidized medium) (for example, patents). Reference 1).

Here, in general, the fluidized bed type gasification furnace is operated in a state in which the generated combustible gas is recovered and the inside of the furnace is maintained at a negative pressure, so that the fluid medium circulation of the combustible gas generated in the furnace is performed. Outflow (leakage) etc. to the channel does not normally occur.
However, if abnormal combustion occurs due to a sudden increase in the amount of waste input or changes in waste properties, or an emergency stop of a fluidized bed gasification furnace occurs, the pressure in the furnace becomes positive and generated in the furnace. There is a possibility that the burned combustible gas flows out to the fluid medium circulation passage. And when combustible gas flows out into a fluid medium circulation channel, stable circulation of a fluid medium is prevented.

  Therefore, in recent years, there has been proposed a fluidized bed gasifier capable of preventing the combustible gas from flowing out into the fluidized medium circulation passage even when the pressure in the fluidized bed gasifier becomes positive. Yes. Specifically, a fluidized medium deposition layer (a portion that does not fluidize the fluidized medium) is provided in the lower part of the fluidized bed gasification furnace, and the fluidized medium circulation flow path on the side where the fluidized medium is returned to the furnace. There has been proposed a fluidized bed gasification apparatus in which an opening is opened in the deposition layer so that a circulated fluid medium is deposited in a fluid medium circulation channel (for example, see Patent Document 2). According to this fluidized bed gasifier, even when the pressure in the fluidized bed gasifier becomes positive, the flow of the combustible gas is caused by the pressure of the fluidized medium accumulated in the fluidized medium circulation passage. Outflow to the medium circulation channel can be prevented.

JP 2001-248815 A JP 2001-241627 A

  However, in the conventional fluidized bed gasification apparatus that forms a fluidized medium deposition layer in a fluidized bed gasification furnace, it is necessary to form a portion in the furnace that does not fluidize the fluidized medium. There was a problem that generation | occurrence | production and production | generation of a by-product became easy to occur.

  Therefore, the present invention can prevent flammable gas from flowing out into the fluid medium circulation passage even when the pressure in the furnace becomes positive, and it is difficult for abnormal combustion and by-product to occur. An object is to provide a fluidized bed gasifier.

An object of the present invention is to advantageously solve the above-described problems, and the fluidized bed gasification apparatus of the present invention has a fluidized medium that forms a fluidized bed in a furnace and is charged into the furnace. A fluidized bed gasification furnace that thermally decomposes combustible materials to generate a combustible gas, and a fluidized medium circulation passage that extracts the fluid medium from the furnace and returns the fluid medium extracted to the furnace again. In the bed gasification apparatus, the fluid medium circulation passage communicates a fluid medium outlet provided in the fluidized bed gasification furnace and a fluid medium return port, and the fluid medium outlet is connected via the fluid medium outlet. A transport mechanism that transports the extracted fluid medium to the fluid medium return port side, a storage unit that stores the fluid medium transported by the transport mechanism, and a valve provided on the fluid medium return port side of the storage unit And the valve and the fluid medium return port And a controller for controlling the opening and closing of the valve, and the controller opens and closes the valve so that the height of the fluid medium stored in the storage part is equal to or higher than a predetermined height. It is characterized by controlling. In this way, if a valve is provided on the fluid medium return port side of the reservoir that stores the fluid medium, the fluid medium is stored in the reservoir without forming a fluidized medium deposition layer in the fluidized bed gasification furnace. can do. If a controller for controlling the opening and closing of the valve is provided so that the height of the fluid medium stored in the reservoir is equal to or higher than a predetermined height, the pressure in the fluidized bed gasifier becomes positive. Even in this case, it is possible to prevent the combustible gas from flowing out into the fluid medium circulation channel by the pressure of the fluid medium accumulated in the storage part.
In the present invention, “the height of the fluid medium stored in the reservoir” refers to the height measured from the bottom surface of the reservoir of the fluid medium layer formed by the fluid medium stored in the reservoir.

  Here, the fluidized bed gasification apparatus of the present invention includes an interlock mechanism that prevents the fluidized bed gasification apparatus from increasing the pressure in the fluidized bed gasification furnace to a predetermined pressure or higher. It is preferable that the height is such that the pressure applied to the bottom surface of the storage part by the fluid medium stored in the storage part is equal to or higher than the predetermined pressure. If the fluidized bed gasifier is provided with an interlock mechanism, and the fluid medium is stored such that the pressure applied to the bottom surface of the reservoir by the fluid medium stored in the reservoir is equal to or higher than the operating pressure of the interlock mechanism. This is because it is possible to reliably prevent the combustible gas from flowing out into the fluid medium circulation passage.

  Moreover, it is preferable that the fluidized bed gasifier of the present invention includes a gate valve on the fluid medium return port side in the chute. If a gate valve is provided, tar content contained in the combustible gas generated in the fluidized bed gasification furnace can be prevented from sticking in the chute, and clogging of the chute can be prevented. It is.

  And the fluidized bed gasifier of this invention is provided with the temperature fall suppression mechanism in which the said chute | shoot suppresses the temperature fall in a chute | shoot. If a temperature decrease suppression mechanism is provided, tar content contained in the combustible gas generated in the fluidized bed gasification furnace can be prevented from sticking in the chute, and the chute can be prevented from being blocked. Because it can.

  According to the present invention, even when the inside of the furnace becomes positive pressure, it is possible to prevent the combustible gas from flowing out to the fluid medium circulation flow path, and it is difficult for abnormal combustion to occur and generation of by-products. A fluidized bed gasifier can be provided.

It is explanatory drawing which shows schematic structure of the typical fluidized-bed gasifier according to this invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
The fluidized bed gasifier according to the present invention thermally combusts a combustible material by partial combustion in a low oxygen concentration atmosphere, and combusts the combustible material with combustible gas (for example, hydrogen, methane, carbon monoxide, etc.). It is a device that converts it into a residue (for example, incombustible material, carbide, ash, etc.). The fluidized bed gasifier of the present invention is not particularly limited, and pyrolyzes wastes such as waste wood and municipal waste as combustibles, reduces the volume of the wastes, and at the time of thermal decomposition of the wastes It can be used when the generated combustible gas is recovered and reused. As combustible materials, in addition to the above-mentioned waste materials, waste materials that are difficult to separate and put in foreign matter and residues (for example, sand and rubble) and industrial waste materials containing sludge such as sewage sludge are used. You can also.

  Here, FIG. 1 shows a schematic configuration of an example of the fluidized bed gasifier of the present invention. A fluidized bed gasification apparatus 10 shown in FIG. 1 has a fluidized medium that forms a fluidized bed 2 in a furnace, and a fluidized bed type gas that generates a combustible gas by thermally decomposing combustibles charged in the furnace. And a fluidized medium circulation passage 8 for extracting the fluidized medium from the fluidized bed gasification furnace 1 and returning the extracted fluidized medium to the fluidized bed gasification furnace 1 again. In the fluidized bed gasifier 10, the combustible material is continuously pyrolyzed while circulating the fluidized medium.

  The fluidized bed gasification furnace 1 includes a fluidized medium forming the fluidized bed 2 inside the furnace, and an air diffuser pipe 21 for fluidizing the fluidized medium by supplying a gas such as air or oxygen gas into the furnace. have. And the fluidized medium which forms the fluidized bed 2 is heated by the heater (not shown) to the temperature which can thermally decompose a combustible material, for example, 450-600 degreeC. In addition, it does not specifically limit as a fluid medium which forms the fluidized bed 2, Known fluid media, such as sand, can be used.

  The fluidized bed gasifier 1 includes a combustible material inlet 4 connected to the combustible material input passage 41, a gas outlet 5 through which combustible gas generated in the fluidized bed gasifier 1 flows out, It has a fluid medium outlet port 6 connected to one end of the fluid medium circulation channel 8 and a fluid medium return port 7 connected to the other end of the fluid medium circulation channel 8. In the fluidized bed gasification furnace 1, the combustible material inlet 4, the gas outlet 5, and the fluid medium return port 7 are open to the empty tower 3 located above the fluidized bed 2. Further, the fluidized medium outlet 6 opens at the lower part of the fluidized bed type gasification furnace 1, more specifically at the lower side of the fluidized bed 2.

  Furthermore, the fluidized bed gasification furnace 1 has a pressure gauge 31 in the empty space 3 in the furnace. The pressure gauge 31 measures the pressure in the furnace and transmits the obtained pressure data in the furnace to the interlock mechanism 11.

  Here, a total of two inlet gate valves 42 and 43 are provided in the combustible input passage 41. In the fluidized bed gasification furnace 1, waste as combustible material is intermittently or continuously charged through the combustible material charging path 41 and the combustible material charging port 4.

  The gas outlet 5 is connected to a gas flow path (not shown), and the combustible gas flowing out from the gas outlet 5 is recovered through the gas flow path and effectively used as fuel or the like. Note that a damper (not shown) is provided in the gas flow path, and the damper adjusts the pressure in the fluidized bed gasifier 1 by adjusting the outflow amount of the combustible gas.

  The interlock mechanism 11 is for preventing the pressure in the fluidized bed gasification furnace 1 from rising above a predetermined pressure. The interlock mechanism 11 closes the inlet gate valves 42 and 43 when the pressure in the furnace measured by the pressure gauge 31 rises to a predetermined value (for example, 2 kPa in gauge pressure) or more, and fluidized bed gas The supply of the combustible material into the converter 1 is shut off to prevent an increase in the pressure in the furnace.

The fluid medium circulation flow path 8 that connects the fluid medium outlet 6 and the fluid medium return port 7 is a separation mechanism 81 that separates incombustible materials from the fluid medium outlet 6 side toward the fluid medium return port 7 side. And a transport mechanism 82 for transporting the extracted fluid medium, a storage unit 83 for storing the fluid medium, a rotary valve 84, and a chute 85.
An outlet valve 61 is provided at the connection between the fluid medium outlet 6 and the fluid medium circulation passage 8. Then, the fluid medium in the fluidized bed gasification furnace 1 is withdrawn intermittently by opening and closing the extraction port valve 61 or continuously by keeping the extraction port valve 61 open.

Here, the separation mechanism 81 is put into the fluidized bed gasification furnace 1 together with the combustible material (waste), and remains in the fluidized bed 2 without being thermally decomposed (for example, metal, rubble, stone, etc.) ) Is separated and removed from the extracted fluid medium. In the separation mechanism 81, the fluid medium and the incombustible material are separated, and the separated incombustible material is disposed of by a known method. On the other hand, the fluid medium is sent to the transport mechanism 82.
As the separation mechanism 81, a known classification device such as a vibration sieve can be used.

  The transport mechanism 82 is for transporting the fluid medium separated by the separation mechanism 81 to the storage unit 83. And as a conveyance mechanism 82, known conveyance apparatuses, such as a bucket conveyor and an air conveyance machine, can be used.

The storage unit 83 temporarily stores the fluid medium transported using the transport mechanism 82. And in the storage part 83, the height of the stored fluid medium, more specifically, the height measured from the bottom surface of the storage part 83 of the fluid medium layer formed by the stored fluid medium is detected. A level meter (not shown) is provided.
The storage portion 83 is not particularly limited, and a hollow cylindrical metal can having a fluid medium inlet on the upper surface and a fluid medium outlet on the lower surface can be used. The level meter is not particularly limited, and a known level meter such as a paddle type (rotary blade type) level meter can be used.

The rotary valve 84 is provided on the lower side (the fluid medium return port 7 side) of the storage unit 83 and is connected to the outlet of the fluid medium provided on the bottom surface of the storage unit 83. The opening and closing of the rotary valve 84 is controlled by the controller 9.
Specifically, the rotary valve 84 starts rotating (opens) when the height of the fluid medium in the storage unit 83 rises to MH, and the height of the fluid medium in the storage unit 83 by sending the fluid medium. Is controlled by the controller 9 so as to stop (close) when the voltage drops to ML.

The chute 85 connects the rotary valve 84 and the fluid medium return port 7. Accordingly, when the rotary valve 84 rotates, the fluid medium sent from the storage unit 83 is returned to the hollow part 3 in the fluidized bed gasification furnace 1 through the chute 85 and the fluid medium return port 7.
The chute 85 has a return port gate valve 86 in the vicinity of the fluid medium return port 7. Further, the chute 85 is provided with a temperature lowering suppression mechanism 87 that suppresses a temperature drop in the chute. As the temperature decrease suppression mechanism 87, a known mechanism that can suppress a temperature decrease in the chute 85, such as a heat insulating material or a heater, can be used.

  Here, opening and closing of the return port gate valve 86 provided on the fluid medium return port 7 side is controlled by the controller 9. Specifically, the opening / closing of the return gate valve 86 is controlled in correspondence with the opening / closing (rotation / stop) timing of the rotary valve 84. That is, the return gate valve 86 is opened at the same time as the rotary valve 84 starts rotating or just before the rotary valve 84 starts rotating, and after the rotary valve 84 stops, the return medium gate valve 86 is turned on for a predetermined time. It is controlled by the controller 9 so as to be closed after a sufficient time).

  The controller 9 controls the opening and closing of the rotary valve 84 and the return port gate valve 86 as described above. Specifically, when the height of the fluid medium in the storage unit 83 rises to MH, the controller 9 opens the rotary valve 84 and the return port gate valve 86, and the height of the fluid medium in the storage unit 83 increases. When the pressure drops to ML, the rotary valve 84 and the return gate valve 86 are closed. That is, the controller 9 controls the opening and closing of the rotary valve 84 and the return gate valve 86 so that the height of the fluid medium in the reservoir 83 is always equal to or higher than the predetermined height ML.

Here, the predetermined height ML is not particularly limited, and the pressure applied to the bottom surface (that is, the rotary valve 84 side) of the storage unit 83 by the fluid medium stored in the storage unit 83 is an interlock. It can be set to a height that is equal to or higher than the pressure (for example, 2 kPa in terms of gauge pressure) at which the mechanism 11 operates to close the inlet gate valves 42 and 43.
More specifically, the height ML can be set to 300 mm or more, for example. In addition, height MH can be made into arbitrary height, for example, 300-500 mm.

  In the fluidized bed gasifier 10 including the fluidized bed gasification furnace 1 and the fluidized medium circulation passage 8 described above, the combustible material introduced from the combustible material inlet 4 is supplied via the air diffuser 21. It can be partially burned using air or the like and thermally decomposed. And the combustible gas which the combustible material produced | generated by thermal decomposition can be collect | recovered via the gas outlet 5 and a gas flow path (not shown), and can be reused. In addition, the outflow amount of the combustible gas from the gas outlet 5 is adjusted by a damper so that the inside of the fluidized bed gasifier 1 has a negative pressure. Therefore, in the fluidized bed gasifier 10, normally combustible gas does not leak out of the furnace.

  Further, in the fluidized bed gasification apparatus 10, a part of the fluidized medium is extracted through the fluidized medium extraction port 6, and the incombustible matter contained in the extracted fluidized medium is separated and removed by the separation mechanism 81, and then the fluidized medium is removed. It is returned to the fluidized bed gasifier 1 again. Therefore, in the fluidized bed gasifier 10, the fluidized medium can be circulated and reused while removing incombustibles from the fluidized bed 2.

Here, in the fluidized bed gasification apparatus 10, a fluid medium having a predetermined height ML or higher is always stored in a storage part 83 provided in the fluid medium circulation channel 8. Therefore, even if abnormal combustion due to a sudden increase in the amount of combustible material input or a change in the properties of combustible material or an emergency stop of the fluidized bed gasification furnace 1 occurs, the combustible gas can be discharged even if the pressure in the furnace becomes positive. Can be prevented from flowing out into the fluid medium circulation passage 8. That is, in the fluidized bed gasification apparatus 10, the controller 9 controls the height of the fluid medium in the reservoir 83 to be equal to or higher than the predetermined height ML, so that the pressure in the furnace becomes positive. Even if the rotary valve 84 and the return port gate valve 86 are opened or there is a gap between the rotary valve 84 and the return port gate valve 86, the fluid medium accumulated by the pressure of the fluid medium accumulated in the reservoir 83 It is possible to prevent the combustible gas from flowing from the return port 7 side into the fluid medium circulation passage 8 (particularly, the storage unit 83 side from the rotary valve 84).
In the fluidized bed gasifier 10, the outflow of the combustible gas to the combustible material input passage 41 is prevented by the double input gate valves 42 and 43 and the combustible material deposited on the input gate valve 43. Can do.

  Further, in the fluidized bed gasification apparatus 10, since the rotary valve 84 is provided on the fluidized medium return port 7 side of the reservoir 83, without forming a fluidized medium deposition layer in the fluidized bed gasification furnace 1, A fluid medium can be stored in the storage part 83. Therefore, the combustible material can be pyrolyzed without forming a part that does not fluidize the fluidized medium in the furnace, so the occurrence of abnormal combustion and the generation of by-products due to the formation of the deposited layer can be suppressed and stable. In this state, the pyrolysis of the combustible material and the circulation of the fluid medium can be continued.

Furthermore, since the fluidized bed gasifier 10 is provided with the interlock mechanism 11, it is possible to prevent the pressure in the fluidized bed gasification furnace 1 from rising to a predetermined pressure or higher. You can drive safely.
Further, in the fluidized bed gasification apparatus 10, the fluid medium stored in the storage unit 83 at a predetermined height ML when the controller 9 closes the rotary valve 84 (that is, stops the rotation of the rotary valve 84). Thus, the pressure applied to the bottom surface of the storage portion 83 is set to be equal to or higher than the pressure at which the interlock mechanism 11 operates. Therefore, the fluidized bed gasifier 10 can reliably prevent the inflow of combustible gas to the fluid medium circulation passage 8, particularly the outflow of combustible gas to the storage unit 83 side from the rotary valve 84.

  The combustible gas generated in the fluidized bed gasification furnace 1 contains tar, but in the fluidized bed gasifier 10, the return gate valve 86 and the temperature drop suppression mechanism 87 are provided in the chute 85. Since it is provided, it is possible to suppress the tar contained in the combustible gas from sticking in the chute 85. Therefore, the fluidized bed gasifier 10 can prevent the chute 85 from being blocked by the tar content in the combustible gas.

  As mentioned above, although the fluidized bed gasifier of the present invention was explained using an example, the fluidized bed gasifier of the present invention is not limited to the above example, and the fluidized bed gasifier of the present invention includes: Changes can be made as appropriate. Specifically, various valves and apparatuses used in the fluidized bed gasifier of the present invention are not limited to the above example.

  According to the fluidized bed gasification apparatus of the present invention, it is possible to prevent the combustible gas from flowing out to the fluidized medium circulation flow path even when the inside of the furnace becomes a positive pressure, and to generate abnormal combustion or by-product. The production of objects can be suppressed.

DESCRIPTION OF SYMBOLS 1 Fluidized bed type gasification furnace 2 Fluidized bed 3 Empty tower part 4 Combustible material inlet 5 Gas outlet 6 Fluidized medium outlet 7 Fluidized medium return port 8 Fluidized medium circulation flow path 9 Controller 10 Fluidized bed gasifier 21 Spatter Trachea 11 Interlock mechanism 31 Pressure gauge 41 Combustible material input path 42, 43 Input port gate valve 61 Extraction port valve 81 Separation mechanism 82 Transport mechanism 83 Reservoir 84 Rotary valve 85 Chute 86 Return port gate valve 87 Temperature drop suppression mechanism

Claims (4)

A fluidized bed gasification furnace having a fluidized medium forming a fluidized bed in the furnace, pyrolyzing a combustible material charged in the furnace to generate a combustible gas, and extracting the fluidized medium from the furnace, A fluidized bed gasification apparatus comprising a fluidized medium circulation passage for returning the extracted fluidized medium back into the furnace,
The fluid medium circulation channel is
The fluidized medium outlet provided in the fluidized bed gasifier and the fluidized medium return port communicate with each other,
A transport mechanism for transporting the fluid medium extracted through the fluid medium outlet to the fluid medium return port;
A storage section for storing the fluid medium transported by the transport mechanism;
A valve provided on the fluid medium return port side of the reservoir;
A chute connecting the valve and the fluid medium return port;
A controller for controlling the opening and closing of the valve;
Have
The fluidized bed gasifier according to claim 1, wherein the controller controls opening and closing of the valve so that a height of a fluid medium stored in the storage unit is equal to or higher than a predetermined height. The fluidized bed gasifier comprises an interlock mechanism for preventing the pressure in the fluidized bed gasification furnace from rising above a predetermined pressure;
2. The flow according to claim 1, wherein the predetermined height is a height at which a pressure applied to a bottom surface of the reservoir by the fluid medium stored in the reservoir is equal to or higher than the predetermined pressure. Floor gasifier.   The fluidized bed gasifier according to claim 1 or 2, further comprising a gate valve on the fluid medium return port side in the chute.   The fluidized bed gasifier according to any one of claims 1 to 3, wherein the chute is provided with a temperature decrease suppressing mechanism that suppresses a temperature decrease in the chute.

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