JP5990978B2 - Fluidized bed system and biomass introduction method - Google Patents

Description

  The present invention relates to a fluidized bed system and a biomass introduction method for processing biomass using a fluidized medium.

  2. Description of the Related Art In recent years, a technology for generating gasified gas by gasifying solid raw materials such as biomass, coal, and tire chips instead of petroleum has been developed. The gasified gas thus generated is used for power generation systems, hydrogen production, synthetic fuel (synthetic petroleum) production, chemical fertilizer (urea) and other chemical products. Biomass, which is an organic resource derived from living organisms such as wood, paper, firewood, seaweed, and raw garbage, is a renewable resource among the solid raw materials used as gasification gas, so it can be used as a fossil fuel such as coal and oil. Expected to be an alternative energy source.

  As a technique for gasifying a solid material, a technique for gasifying a solid material by introducing it into a fluidized bed gasification furnace using steam has been developed. In such a fluidized bed gasification furnace, as a technique for introducing a solid raw material, gas conveyance, drop conveyance using a hopper (for example, Patent Document 1), conveyance using a twin screw feeder (for example, patent) Reference 2) is used.

JP 2010-254728 A Patent No. 3675636

  However, among biomass, fibrous biomass such as wood, paper, and firewood contains a large amount of air between the fibers, so even if an attempt is made to convey the gas, the gas passes between the fibers and cannot be conveyed. Moreover, even if the fall conveyance of patent document 1 is utilized, in the pipe connecting the discharge port of the hopper and the gasification furnace, fibers in the biomass are intertwined to form a bridge, deposit, and block the pipe. End up. Furthermore, even if the biaxial screw type feeder of Patent Document 2 is used, the fibrous biomass contains a large amount of air between the fibers, so the inside of the screw type feeder is not sealed, and the gas in the gasifier is not sealed. There was a problem that the gas flowed back to the screw type feeder or the introduction side atmosphere gas was mixed into the gasification furnace.

  Therefore, in view of such problems, the present invention provides a fluidized bed system and a biomass introduction method capable of reliably introducing biomass into a fluidized bed furnace with a simple configuration and without blocking the piping. It is aimed.

In order to solve the above problems, a fluidized bed system according to the present invention includes a drop transport unit that drops and transports a fluid medium, a raw material input unit that feeds biomass into the fluid medium that is being dropped and transported, and the drop transport unit A mixing unit that further mixes the fluid medium and the input biomass to generate a mixture, a derivation unit that derives the mixture, a fluidized bed of the fluid medium, and a mixture derived by the derivation unit And a fluidized bed furnace to be introduced.

The present invention may also be obtain Bei a first heating section for heating the fluid medium.

Further, the functions as dropping conveying means, provided with a media reservoir for storing the fluid medium, the first heating portion may Rutoshite that Nessu pressurizing said fluid medium in said medium reservoir.

  Moreover, it is good also as providing the 2nd heating part which heats the said mixture in the said derivation | leading-out part.

  The lead-out portion includes a screw feeder that rotates a helical screw and feeds the mixture in the direction of the rotation axis, and an outlet of the screw feeder is a position filled with a fluid medium in the fluidized bed furnace. It may be connected to.

In order to solve the above problems, a biomass introduction method of the present invention is a biomass introduction method for introducing biomass into a fluidized bed furnace for fluidizing a fluidized medium, a step of dropping and conveying the fluidized medium, and a drop conveying A step of introducing the biomass into the fluidized medium, a step of further mixing the fluidized medium dropped and transported with the input biomass, and generating the mixture in the fluidized bed furnace. And a step of introducing.

  According to the present invention, it is possible to reliably introduce biomass into a fluidized bed furnace with a simple configuration and without blocking the piping.

It is a figure for demonstrating the specific structure of a fluidized bed system. It is a figure for demonstrating the specific structure of a raw material introduction apparatus. It is a flowchart for demonstrating the flow of a process of a biomass introduction method. It is a figure for demonstrating the specific structure of the fluidized bed system concerning a modification.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. The dimensions, materials, and other specific numerical values shown in the embodiments are merely examples for facilitating the understanding of the invention, and do not limit the present invention unless otherwise specified. In the present specification and drawings, elements having substantially the same function and configuration are denoted by the same reference numerals, and redundant description is omitted, and elements not directly related to the present invention are not illustrated. To do.

(Fluidized bed system 100)
FIG. 1 is a diagram for explaining a specific configuration of a fluidized bed system 100 according to the present embodiment. As shown in FIG. 1, the fluidized bed system 100 includes a combustion furnace 102, a medium separator 104, a gasification furnace (fluidized bed furnace) 110, and a raw material introduction device 200.

  In the present embodiment, the fluidized bed system 100 is a circulating fluidized bed gasification system, and as a whole, a fluidized medium composed of sand such as dredged sand (silica sand) having a particle size of about 300 μm is circulated as a heat medium. Yes. Specifically, the fluid medium is first heated to about 1000 ° C. in the combustion furnace 102 and introduced into the medium separator 104 together with the combustion exhaust gas. In the medium separator 104, the high-temperature fluid medium and the combustion exhaust gas are separated, and the separated high-temperature fluid medium is introduced into the gasification furnace 110.

  On the other hand, the combustion exhaust gas separated by the medium separator 104 is recovered by a heat exchanger (not shown) or the like. The fluid medium introduced into the gasification furnace 110 is fluidized by the gasifying agent (here, steam) introduced from the steam storage part 112 and returned to the combustion furnace 102.

  A water vapor storage unit 112 is provided below the gasification furnace 110, and water vapor supplied from a water supply source (not shown) is temporarily stored in the water vapor storage unit 112 and stored in the water vapor storage unit 112. Steam is introduced into the gasification furnace 110 from the bottom of the gasification furnace 110. As described above, by introducing water vapor into the high-temperature fluid medium introduced from the medium separator 104, a fluidized bed (bubble fluidized bed) is formed in the gasification furnace 110.

  Further, the gasification furnace 110 is provided with a raw material introduction device 200 for introducing biomass into the fluidized bed. Biomass input from the raw material introduction apparatus 200 is gasified by heat of about 700 ° C. to 900 ° C. of the fluidized medium fluidized by water vapor, thereby generating gasified gas.

  Among biomass used as raw materials for gasification gas, fibrous biomass such as wood, paper, and firewood contains a large amount of air between fibers (for example, some fluff-shaped ones), so conventional air current transportation In addition, it is difficult to introduce biomass into the gasification furnace 110 by transport using drop transport. Therefore, conventionally, since the biomass was processed into a pellet form and then introduced into the gasification furnace 110, the pretreatment was expensive.

  Therefore, the raw material introduction device 200 of the present embodiment reliably introduces fibrous biomass among the biomass into the gasification furnace 110. Below, the specific structure of this raw material introduction apparatus 200 is demonstrated.

(Raw material introduction device 200)
FIG. 2 is a diagram for explaining a specific configuration of the raw material introduction apparatus 200. As shown in FIG. 2, the raw material introduction apparatus 200 includes a medium storage unit 210, a first heating unit 212, a raw material transport unit 220, a mixing unit 230, a derivation unit 240, and a second heating unit 250. Consists of including.

  The medium storage unit 210 is configured by, for example, a hopper, temporarily stores the fluid medium used in the fluidized bed system 100, and drops the fluid medium to a hopper 232 described later (drop conveyance). The medium storage unit 210 is provided with a first heating unit 212, and the first heating unit 212 heats the fluid medium stored in the medium storage unit 210.

  The raw material conveyance part 220 is comprised with a belt conveyor, for example, and conveys fibrous biomass to the hopper 232. Here, the biomass conveyed by the raw material conveyance unit 220 may be in any form, and examples thereof include fibrous biomass such as wood, paper, and firewood, waste, and debris.

  The mixing unit 230 includes a hopper 232 and a stirring blade 234. In the hopper 232, the fluid medium transported from the medium storage unit 210 and the biomass transported from the raw material transport unit 220 are introduced. Then, the agitating blade 234 provided in the hopper 232 is rotationally driven by a drive source (not shown), whereby the fluid medium and the biomass are mixed to produce a mixture (a mixture of the fluid medium and the biomass).

  The deriving unit 240 derives the mixture generated by the mixing unit 230 through the pipe 242 and introduces the mixture into the gasification furnace 110. Specifically, in the present embodiment, the lead-out unit 240 includes a screw feeder that rotates a helical screw and feeds the mixture in the direction of the rotation axis.

  The second heating unit 250 is provided in the vicinity of the connection position with the gasification furnace 110 in the pipe 242 and heats the mixture in the pipe 242.

  Thus, the lead-out part 240 can fill the space between fibers in the biomass with the fluid medium by introducing the fluid medium into the gasification furnace 110 together with the biomass instead of the biomass. Therefore, it is possible to avoid a situation in which the fibers in the biomass are intertwined to form a bridge and the pipe 242 is blocked.

  In addition, since the density of the fluid medium (mass per unit volume) is larger than the density of the biomass, it is transported at a higher pressure than the case of transporting only biomass by using a mixture of biomass and fluid medium. can do. Therefore, even if the biomass forms a bridge in the pipe 242, the biomass can be pushed out to the gasifier 110 with a large pressure corresponding to the density of the fluid medium.

  Furthermore, by mixing the biomass and the fluid medium in the mixing unit 230, the biomass is dispersed in the fluid medium without deviation in the gasification furnace 110. Therefore, biomass can be gasified substantially uniformly, and gasification efficiency can be improved.

  In addition, with the configuration including the first heating unit 212 and the second heating unit 250, the temperature of the fluid medium in the mixture can be increased, and heat loss in the gasification furnace 110 can be reduced. Become.

  Next, the position of the outlet of the screw feeder in the lead-out unit 240 (connection position between the gasification furnace 110 and the pipe 242) will be described.

  If the outlet of the screw feeder is connected to the upper part of the gasification furnace 110 and is not filled with the fluid medium, the water vapor in the gasification furnace 110 may flow backward to the pipe 242. Therefore, as shown in FIG. 2, the outlet of the screw feeder (connection position between the gasification furnace 110 and the pipe 242) in the outlet section 240 is connected to a position in the gasification furnace 110 that is filled with the fluid medium.

  With such a configuration, the piping 242 is filled with biomass and a fluid medium, and has a sealing function that shuts off the gasification furnace 110 and the hopper 232. Therefore, it is possible to avoid a situation in which the water vapor in the gasification furnace 110 flows backward to the pipe 242 and a situation in which the atmospheric gas in the hopper 232 is mixed into the gasification furnace 110. Therefore, the hopper 232 can be opened to the atmosphere, and it is not necessary to replace the medium storage unit 210, the raw material transfer unit 220, and the mixing unit 230 with an atmosphere gas that does not cause a problem even if the medium storage unit 210 is introduced into the gasification furnace 110. In addition, the configuration of the raw material transport unit 220 and the mixing unit 230 can be simplified.

  As described above, the outlet of the screw feeder is preferably connected to a position in the gasification furnace 110 where the fluidized medium is filled. However, as the connection position moves toward the bottom surface in the gasification furnace 110, the fluidized bed exits. The load increases, the pressure required for conveyance increases, and the power consumption used by the drive source increases. Therefore, the outlet of the screw feeder is preferably connected to a position near the interface between the fluidized bed and the gas layer in the gasification furnace 110 and filled with the fluidized medium.

  As described above, the pipe 242 has a sealing function, but there is a possibility that the water vapor flows backward from the gasification furnace 110. As a result, the flow of water in the pipe 242 may be fixed due to condensation of the back-flowed water vapor, and the pipe 242 may be blocked. Therefore, by providing the second heating unit 250, even if water vapor flows back from the gasification furnace 110, condensation into water can be suppressed, and the blockage of the pipe 242 can be reliably prevented. It becomes.

  Here, since the fluid medium other than the fluid medium circulating in the combustion furnace 102, the medium separator 104, and the gasification furnace 110 is introduced from the raw material introduction apparatus 200 to the gasification furnace 110, the fluid medium to be circulated The amount will increase. Therefore, as shown in FIG. 1, a discharge unit 120 is provided, and the flow medium introduced by the raw material introduction apparatus 200 is discharged, so that the amount of the flow medium to be circulated is maintained substantially equal.

(Biomass introduction method)
FIG. 3 is a flowchart for explaining the process flow of the biomass introduction method according to the present embodiment. As shown in FIG. 3, the mixing unit 230 first generates a mixture by mixing the fluid medium introduced from the medium storage unit 210 and the biomass introduced from the raw material transport unit 220 (S300). And the derivation | leading-out part 240 derives | leads-out the mixture produced | generated by the mixing part 230, and introduces it into the gasification furnace 110 (S310).

  As described above, according to the raw material introduction apparatus 200 and the biomass introduction method using the raw material introduction apparatus according to the present embodiment, the piping is configured with a simple configuration in which a fluid medium is mixed with biomass and introduced into the gasification furnace 110. The biomass can be reliably introduced into the gasification furnace 110 without blocking the 242.

(Modification)
In the embodiment described above, the fluidized bed system 100 has been described by taking the gasification furnace 110 that performs steam gasification in a circulating fluidized bed gasification system as a fluidized bed furnace. However, other fluidized bed furnaces can be utilized in the fluidized bed system.

  FIG. 4 is a diagram for explaining a specific configuration of fluidized bed systems 400 and 450 according to the modification. For example, as shown in FIG. 4A, a fluidized bed system 400 according to a modification employs a bubbling fluidized bed furnace 410 that does not circulate a fluidized medium as a fluidized bed furnace. A mixture of biomass and fluidized medium may be introduced into the furnace 410. In this case, the fluid medium introduced by the raw material introduction device 200 may be discharged to the outside through the loop seal 412.

  Moreover, as shown in FIG.4 (b), the other fluidized bed system 450 concerning a modification employ | adopts the circulating fluidized bed furnace 460 which does not provide the gasification furnace used for a boiler etc. as a fluidized bed furnace. The mixture of biomass and fluidized medium may be introduced into the circulating fluidized bed furnace 460 by the raw material introducing device 200. When the circulating fluidized bed furnace 460 is used as a boiler, a heat exchanger 462 may be provided downstream of the medium separator 104 and the fluid medium cooled by the heat exchanger 462 may be discharged to the outside. In this case, the heat recovered by the heat exchanger 462 may be used by the first heating unit 212 or the second heating unit 250.

  As mentioned above, although preferred embodiment of this invention was described referring an accompanying drawing, it cannot be overemphasized that this invention is not limited to this embodiment. It will be apparent to those skilled in the art that various changes and modifications can be made within the scope of the claims, and these are naturally within the technical scope of the present invention. Is done.

  For example, in the above-described embodiment, the configuration in which the medium storage unit 210 drops and conveys the fluid medium has been described. However, the conveyance unit of the medium storage unit 210 is not limited, and may be a belt conveyor or the like. Similarly, although the case where the material conveyance unit 220 is configured by a belt conveyor has been described as an example, the conveyance means is not limited and may be fall conveyance or the like.

  Further, the medium storage unit 210 may store the fluid medium once discharged by the discharge unit 120, or the medium separator 104 may function as the medium storage unit 210.

  Furthermore, in the above-described embodiment, the gasification furnace 110 that performs steam gasification is described as an example of the fluidized bed furnace, but the fluidized bed furnace may be a gasification furnace that gasifies with a gas other than steam. For example, a combustion furnace may be used instead of the gasification furnace.

  INDUSTRIAL APPLICABILITY The present invention can be used for a fluidized bed system and a biomass introduction method that process biomass using a fluidized medium.

100, 400, 450 ... Fluidized bed system 110 ... Gasification furnace (fluidized bed furnace)
112 ... Water vapor storage part 212 ... Heating part (first heating part)
230 ... mixing unit 240 ... deriving unit 250 ... heating unit (second heating unit)
410 ... Bubble fluidized bed furnace (fluidized bed furnace)
460 ... circulating fluidized bed furnace (fluidized bed furnace)

Claims (6)

A drop transport means for dropping and transporting the fluid medium;
Raw material input means for introducing biomass into the fluid medium being dropped and conveyed,
And dropping conveyed the fluid medium, a mixing unit for generating a further mixed to the mixture and the entered the biomass,
A deriving unit for deriving the mixture;
A fluidized bed furnace into which the fluidized medium is fluidized and into which the mixture derived by the deriving unit is introduced;
A fluidized bed system characterized by comprising: Fluidized bed system according to claim 1, wherein the obtaining Bei a first heating section for heating the fluid medium. While functioning as the drop conveying means, comprising a medium storage unit for storing the fluid medium,
Wherein the first heating section, a fluidized bed system according to claim 2, characterized in Rukoto that Nessu pressurizing said fluid medium in said medium reservoir.   The fluidized bed system according to any one of claims 1 to 3, further comprising a second heating unit that heats the mixture in the derivation unit. The lead-out portion is configured to include a screw feeder that rotates a helical screw and feeds the mixture in the direction of the rotation axis.
The fluidized bed system according to any one of claims 1 to 4, wherein an outlet of the screw feeder is connected to a position filled with a fluidized medium in the fluidized bed furnace. A biomass introduction method for introducing biomass into a fluidized bed furnace for fluidizing a fluidized medium,
Dropping and transporting the fluid medium;
Introducing the biomass into the fluid medium being dropped and transported;
And dropping conveyed the fluid medium, and generating a further mixed to the mixture and the entered the biomass,
Introducing the mixture into the fluidized bed furnace;
The biomass introduction | transducing method characterized by including.

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