JP6552857B2 - Gasification furnace - Google Patents

Description

  The present invention relates to a gasifier that obtains a gas as a raw material of energy from biomass.

Biomass refers to renewable organic organic resources excluding fossil resources. CO ₂ the biomass is discharged by burning is inherently since it is CO ₂ absorbed from the atmosphere by photosynthesis in organisms growth process, sometimes not a causative agent of global warming, renewable It is noted as an energy source.

  Conventionally, technology has been established to ferment and filter edible raw materials such as sugarcane and corn, convert them to alcohol, and use them as an alternative fuel. However, this may lead to shortages of edible raw materials and high prices. Therefore, in recent years, attention has been focused on the technology that puts non-edible raw materials such as rice straw, rice husk, and wood waste into a gasification furnace, gasifies them by water gas reaction, and turns the resulting gas into liquid fuel by FT synthesis. It is done.

  In general, the water gas reaction that generates carbon monoxide and hydrogen from biomass and water vapor is an endothermic reaction, and the furnace temperature of the gasifier is maintained at 500 ° C. to 1200 ° C. in order to promote the reaction.

  Patent Document 1 discloses a screw feeder device used in a refuse incinerator intended to transfer an object to be transferred in the presence of atmospheric pressure without providing a special sealing device in a negative pressure atmosphere container. . In the screw feeder, the screw is removed at least on the inlet side from the outlet. Therefore, the transferred object is transferred only by the pressing force of the transferred object transferred from the rear, and is consolidated in the casing, whereby the consolidated state is promoted and maintained. As a result, it is described that when transferring the object to be transferred under atmospheric pressure into the container under negative pressure, there is an effect that sufficient sealing can be performed by the object to be transferred compacted in the screw feeder device.

  Further, Patent Document 2 discloses a powder and particle supply device that quantitatively supplies biomass powder and particles. The powder supply apparatus transports the stored granular material along the horizontal direction, and feeds the transferred granular material from a lower opening, and the base end side is connected to the opening of the hopper. The first screw feeder that feeds the powder particles from the tip side without compressing them, and the base end side is connected to the tip side of the first screw feeder, and the powder particles while closing the tip side with the powder particles And a second screw feeder for delivering the

  The second screw feeder includes a screw in which the pitch interval on the distal end side is set to be smaller toward the distal end side than the proximal end side, or the blade height on the distal end side is smaller toward the distal end side than the proximal end side. And a casing formed in a tapered shape so that the diameter on the distal end side becomes smaller toward the distal end side than the proximal end side in accordance with the blade height of the screw. It is comprised so that the said biomass may be sent from the front end side of a casing, closing the front end side of a casing with biomass.

  Therefore, the inside of the casing and the inside of the gasification furnace can be partitioned by biomass, and the gasifying agent in the gasification furnace can be pushed in, making it difficult to back flow into the screw feeder and pushing from the seal gas feeding device. The amount of seal gas flowing out into the gasification furnace via the screw feeder can be greatly reduced.

JP-A-9-175626 JP 2004-512258 A

  However, when the screw feeder device described in Patent Document 1 is used in a high-temperature gasification furnace, the cavity formed at the tip of the casing of the screw blade after being dropped and supplied from the tip of the screw feeder into the furnace is heated to a high temperature. When exposed, some biomass in the casing is thermally decomposed and fixed before being introduced into the gasification furnace, or the generated tar adheres to the inner wall of the casing and grows, or the biomass is tar or water vapor. As the condition continues, there is a problem that the screw feeder is eventually closed. Since the temperature in the casing is slightly lower than that in the furnace, tar and water vapor are cooled and adhere and solidify.

  The screw feeder described in Patent Document 2 is configured so that the pitch of the screw blades is narrower toward the tip side so that the biomass is consolidated toward the tip side of the casing, or the casing is reduced in diameter toward the tip side. Although the property is excellent, there is a possibility that the tar component generated by thermal decomposition of biomass on the inner tip side of the casing infiltrates into the biomass and decreases in temperature, and is agglomerated and clogged.

  In particular, when the screw feeder is intermittently operated, the agglomeration progresses at the time of stopping, and a large torque is generated during the subsequent operation, which may cause mechanical damage.

  An object of the present invention is to provide a gasification furnace including a biomass supply apparatus that can stably supply biomass without causing internal clogging or supply failure due to tar or the like in view of the above-described problems. It is on the point.

In order to achieve the above-mentioned object, the first characteristic configuration of the gasification furnace according to the present invention includes an oxygen gas supply unit, a water vapor supply unit, a biomass supply device, as described in claim 1 of the claims. Is a gasification furnace which is provided on the furnace wall and causes a water gas reaction in the furnace, and the biomass supply device is a tubular shape having a biomass inlet formed on the base end side and a tip end side connected to the furnace wall And a screw blade inserted into the cylindrical casing, and configured to convey and supply the biomass introduced into the biomass inlet into the furnace, and the cylindrical member is arranged along the conveying direction. the volume of the section which is formed between one pitch of the casing and the screw blade is configured to be larger at the distal end side as compared to the base end side, shorter configuration than the support shaft is the length of the screw blade of the screw blade It lies in the fact that is.

  Biomass is filled and transported in a space defined by the cylindrical casing and the screw blades, and is sealed so that outside air does not flow into the furnace by the biomass filled in the space. Since the support shaft of the screw blade is configured to be shorter than the length of the screw blade, the distal end of the support shaft of the screw blade is held from the furnace wall to the proximal end side, and is not easily exposed to high temperatures. This makes it difficult for the biomass to agglomerate and adhere to the spindles of the screw blades due to condensation of tar and water vapor. In addition, since there is no screw blade support shaft on the front end side of the cylindrical casing, the biomass filling rate on the front end side of the cylindrical casing is further reduced, so that the biomass on the front end side of the cylindrical casing is Cohesive adhesion to the cylindrical casing is less likely to occur and stable supply to the furnace is possible.

In addition, since the volume per unit length is larger on the distal end side than on the proximal end side, the biomass transported to the distal end side of the cylindrical casing is transported from the compacted state on the proximal end side to the distal end side. Then it is released and it is in a state of being unraveled. Even if some biomass exposed to high temperature on the tip side of the cylindrical casing is pyrolyzed, it is not so compacted, so it will be transported into the furnace before tar infiltrates the surrounding biomass become. In addition, even if some biomass gets wet with tar or steam, it will be transported into the furnace with screw blades.

  As described in claim 2, the second feature configuration is configured such that, in addition to the first feature configuration described above, the pitch of the screw blades is longer on the distal end side than on the proximal end side. The point is.

  According to the above-described configuration, the filling rate of the biomass conveyed in the cylindrical casing is smaller on the distal end side than the proximal end side of the cylindrical casing, thereby, on the proximal end side of the cylindrical casing, The sealing biomass is secured by the compacted biomass, and at the same time, the biomass on the tip side of the cylindrical casing that is not compacted is less likely to agglomerate and adhere to the cylindrical casing, and can be stably supplied to the furnace. become.

In the third feature configuration, as described in claim 3, in addition to the first feature configuration described above, the pitch of the screw blades is shorter at the intermediate portion and longer at the distal end side than at the proximal end side. It is in the point comprised so that.

  According to the above-described configuration, the filling rate of biomass moving in the cylindrical casing is smaller on the distal end side than on the proximal end side of the cylindrical casing. As a result, the uncompressed biomass on the front end side of the cylindrical casing is less likely to agglomerate and adhere to the cylindrical casing, and can be stably supplied into the furnace. Furthermore, since the filling rate of the biomass in the middle part of the cylindrical casing is larger than that on the base end side, the sealing effect is increased, the inflow of outside air into the gasifier, and the gasifying agent in the gasifier Can be suppressed.

The fourth characterizing feature of the can, as noted in the claim 4, in addition the first above the third one characteristic feature of the, extending the tip of the screw blade until near the inner wall of the furnace wall formed It is in the point being done.

  According to the above configuration, since the tip of the screw blade extends to the vicinity of the inner wall of the furnace wall, the biomass can be directly pushed out mechanically by the screw blade and supplied into the furnace. Even when tar or the like adheres to the inner wall of the cylindrical casing in the vicinity of the inner wall of the furnace wall and the cylindrical casing becomes blocked, the cylindrical casing is inserted and rotated. It is possible to peel off tar and the like attached by the screw blade. In the first place, since the screw blades are rotating, tar or the like is less likely to adhere to the inner wall of the cylindrical casing. Therefore, it becomes possible to reliably supply biomass quantitatively.

In the fifth feature configuration, as described in claim 5 , in addition to any one of the first to third feature configurations described above, the tip of the screw blade is formed to protrude inside the furnace wall. The point is.

  According to the above-described configuration, since the tip of the screw blade is formed so as to protrude to the inside of the furnace wall, the same effect as that of the above-described fifth characteristic configuration can be more reliably exhibited.

The sixth characterizing feature of the can, as noted in the claim 6, in addition the first above Fifth any feature configuration of the diameter of the tubular casing and the screw blade along the transport direction Is configured to be larger on the distal end side than on the proximal end side.

  According to the above-described configuration, it is possible to make the filling rate of biomass conveyed in the cylindrical casing smaller on the distal end side than on the proximal end side of the cylindrical casing. Thereby, at the base end side of the cylindrical casing, the sealing performance is ensured by the compacted biomass, and at the same time, the unconsolidated biomass on the distal end side of the cylindrical casing is aggregated by tar or the like to form a cylindrical casing. It becomes difficult to adhere and the biomass can be stably supplied into the furnace.

According to a seventh aspect of the present invention, in addition to any of the first to sixth features described above, the furnace main body surrounded by the furnace wall is formed in a bowl shape, as described in the seventh aspect. The biomass supply apparatus is in a point connected to the furnace wall at a position above the water vapor supply unit.

  According to the above-described configuration, the biomass supplied into the furnace from the biomass supply device located above the steam supply unit connected to the furnace wall of the vertical furnace body is heated to the high temperature supplied from the steam supply unit. The water vapor reaction is carried out with high efficiency by the jet of water vapor from below.

The eighth characterizing feature of the can, as noted in the claim 8, in addition the first above the seventh one characteristic feature of the outside of the furnace wall is covered with a heat insulating material, of the screw blade Of these, at least the tip side of the support shaft is covered with a heat insulating material.

  According to the above-described configuration, the support shaft of the screw blade is unlikely to become high temperature, thereby suppressing the deterioration of the screw blade. In addition, the load on the screw blade cooling mechanism can be reduced.

  As described above, according to the present invention, it is possible to provide a gasification furnace including a biomass supply apparatus that can stably supply biomass without causing internal clogging or supply failure due to tar or the like. It became possible.

Partial cutaway explanatory view of a gasifier according to the present invention (A) is principal part explanatory drawing of the gasification furnace by this invention, (b) is the sectional view on the AA line of (a). Explanation of supply amount control mechanism (A), (b), (c) is explanatory drawing of the gasification reaction of biomass, (d) is a table | surface which shows an experimental result. (A), (b), (c), (d) is a main part explanatory drawing of the gasification furnace by this invention which shows another embodiment. (A), (b), (c) is explanatory drawing of the biomass supply apparatus used for the gasification furnace by this invention Explanatory drawing of the liquid fueling system of biomass in which the gasifier according to the present invention is incorporated Explanatory drawing of the energy generation system incorporating the gasification furnace by this invention

Hereinafter, embodiments of the gasification furnace according to the present invention will be described.
As shown in FIG. 7, a gasification furnace 10 according to the present invention is a gasification furnace that can be incorporated into a liquid fuel conversion system 100 that generates liquid fuel from synthesis gas generated using biomass as a raw material. In addition, the synthesis gas produced | generated in the said gasification furnace 10 can be utilized also as an electric power generation or another heat source.

  A liquid fuel conversion system (BTL system) 100 includes a gasification furnace 10 that generates synthesis gas as a raw material for liquid fuel from biomass, solids such as ash, hydrogen sulfide gas, hydrogen chloride gas, and ammonia from the generated synthesis gas FT synthesizing device 104 for synthesizing fuel from synthesis gas purified through a gas purifying device 204 including a cyclone, a scrubber, an activated carbon adsorption tower, etc.

The gasification furnace 10 is equipped with a reaction tower which reduces and heats the biomass with steam or superheated steam to produce a synthesis gas (H ₂ , CO) at a high temperature of 500 ° C. or more and 1000 ° C. or less. The synthesis gas obtained in the reaction tower is purified by the gas purification device 204 in the latter stage, and after impurities are removed, it is heated and pressurized to a high temperature and high pressure through a heater and a compressor, and introduced into the FT synthesis device 104.

FT synthesis is an abbreviation of Fischer-Tropsch synthesis, and refers to a series of synthetic reaction processes for synthesizing liquid hydrocarbons from carbon monoxide and hydrogen using catalytic reaction. The synthesis gas charged into the FT synthesizer 104 is charged into a solvent in which the catalyst is dispersed and synthesized into a desired hydrocarbon. Although it changes depending on the type and properties of the catalyst, for example, when synthesizing methanol, it may be preferable that the ratio H ₂ / CO of hydrogen to carbon monoxide be about 2. In addition, when synthesizing light oil in this embodiment, the ratio H ₂ / CO of hydrogen to carbon monoxide is preferably about 1.

That is, in order to efficiently obtain the desired hydrocarbon in the FT synthesis, it is preferable that the ratio H ₂ / CO of hydrogen and carbon monoxide be adjusted, and this ratio is an FT even when obtaining the same type of hydrocarbon. It also depends on the type of catalyst used in the synthesis.

Therefore, a highly versatile gasifier 10 capable of obtaining synthesis gas at various ratios H ₂ / CO is desired, and a compact gasifier 10 with a high yield of synthesis gas is desired.

FIG. 1 shows an example of a gasification furnace 10 according to the present invention.
The gasification furnace 10 is supported by a frame, a vertical cylindrical reaction tower 4 made of corrosion-resistant metal, a biomass feeder 2 for supplying biomass to the reaction tower 4, and a water gas reaction. A steam supply section 3 for supplying steam to the reaction tower 4 and an oxygen gas supply section 5 (5a) for heating the reaction tower 4 to a desired temperature and adjusting the ratio H ₂ / CO of hydrogen and carbon monoxide as synthesis gas. , 5b, 5c).

  For example, water vapor and biomass heated to about 500 ° C. at normal pressure by high-frequency heating or the like undergo a water gas reaction or a water gas shift reaction inside the reaction tower 4 and are exhausted from the exhaust port 40 at the top of the reaction tower 4. It is led to the above-mentioned gas purification device 204 (see FIG. 7) through the exhaust pipe. The water gas reaction mainly occurs in the lower part of the reaction tower 4 and the water gas shift reaction mainly occurs in the process of rising the reaction tower 4. The gas purification apparatus 204 (see FIG. 7) is provided with an induction fan, the inside of the reaction tower 4 is maintained at a negative pressure, and the gas generated in the reaction tower 4 is attracted to the gas purification apparatus 204 (see FIG. 7). Be refined.

  The biomass supply apparatus 2 includes a cylindrical casing 20 having one end flange-connected to the lower side of the reaction tower 4 and a screw conveyor mechanism including a screw blade 21 accommodated in the cylindrical casing 20. An inlet 22 for biomass is provided at the other end of 20 (hereinafter simply referred to as “casing”). A conveyance path 70 having a substantially vertical posture is connected to the insertion port 22, and a hopper 7 having a quantitative supply mechanism 71 is provided at the upper end of the conveyance path 70.

  Dry biomass such as rice straw, rice husk, wheat straw, corn stover and the like is preferably used as the raw material biomass. These dry biomass crushed to about several mm is filled in the hopper 7 and conveyed to the inlet 22 through the conveyance path 70. The biomass introduced into the inlet 22 is compactly conveyed by the screw blade 21 and introduced into the reaction tower 4. That is, between the outside air and the inside of the reaction tower 4 is sealed with the packed and consolidated biomass inside the casing 20.

  A first oxygen gas supply unit 5 (5a) is provided below the biomass supply device 2, and a water vapor supply unit 3 is provided below the first oxygen gas supply unit 5 (5a). A plurality of other oxygen gas supply units 5 (5b, 5c) are provided above the biomass supply device 2 at different vertical positions.

  The heat insulation wall W is installed in the reaction tower 4 so as to surround the reaction tower 4 in order to maintain the temperature in the tower. A plurality of heaters H are embedded inside the heat insulating wall W, particularly below the reaction tower 4 in order to maintain the reaction tower 4 at a desired temperature (see FIG. 2B).

  As shown in FIG. 2 (a), the biomass B supplied from the biomass supply device 2 to the inside of the reaction tower 4 is generated by the water vapor sprayed from the nozzle 30 provided at the tip of the water vapor supply part 3. A spouted bed 8 that flows inside is formed.

  The opening 30a of the nozzle 30 is sprayed toward the bottom 41 of the reaction tower 4 and blows upward while rolling up the biomass that has fallen toward the bottom 41 or is falling. The region where the spouted bed 8 in the lower part of the reaction tower 4 is formed is the first region R1 where the water gas reaction is mainly performed. Further, a second region R2 (see FIG. 1) in which a water gas shift reaction is mainly performed is formed above the first region.

The water gas reaction is an endothermic reaction in which carbon monoxide CO and hydrogen H ₂ are generated from solid carbon C and steam H ₂ O as biomass in a high temperature environment of 500 ° C. or higher as shown in the following formula. .
C + H ₂ O → CO + H ₂

The water gas shift reaction is an exothermic reaction in which carbon dioxide CO ₂ and hydrogen H ₂ are generated from carbon monoxide CO and water vapor H ₂ O in a high temperature environment of 800 ° C. or higher as shown in the following equation.
CO + H ₂ O → CO ₂ + H ₂

  Since a water gas reaction which is an endothermic reaction is promoted in a high temperature environment of 500 ° C. or higher, a heating source is required. Therefore, the heater H and the oxygen gas supply unit 5 (5a) described above are provided.

  As shown in FIG. 2B, the heater H is energized while the reaction tower 4 is surrounded by the heat insulating wall W, whereby the inside of the reaction tower 4 is heated to 500 ° C. or higher.

Returning to FIG. 2A, after that, part of the biomass B flowing in the first region R1 is burned by the oxygen gas supplied from the first oxygen gas supply unit 5 (5a) to become carbon dioxide. A high ambient temperature is maintained by the reaction. It is the biomass which the particle | grains painted black in FIG. 2 (a) burned. That is, the temperature is maintained by external heating from the heater H or internal heating by partial combustion of the biomass B.
C + O ₂ → CO ₂
C + 1/2 · O ₂ → CO

  A second oxygen gas supply unit 5 (5b) is also provided above the biomass supply device 2 in the first region R1, and the biomass is partially combusted by oxygen supplied from the second oxygen gas supply unit 5 (5b). The environmental temperature is maintained. Of course, the amount of oxygen gas supplied from these oxygen gas supply units 5 is sufficient for a stable water gas reaction to occur, and is not such an amount that most of the biomass burns and disappears.

  Since the biomass B supplied from the biomass supply apparatus 2 is supplied to the reaction tower 4 without being heated and falls downward in the reaction tower 4, the temperature near the lowermost part of the spouted bed is lowest. Therefore, it is important that the first oxygen gas supply unit 5 (5a) is disposed in the vicinity thereof. In addition, the position of the second oxygen gas supply unit 5 (5b) is also important in order to maintain a sufficient environmental temperature even above the biomass supply device 2 in the first region. This is because the heater H is basically used as a heat source at start-up, and thereafter, the environmental temperature is maintained by the combustion reaction of oxygen gas and biomass B.

  That is, the water vapor supply unit 3 is disposed upstream (downward in FIG. 2) from the biomass supply device 2 along the gas flow direction, and the oxygen gas supply unit 5a corresponding to the first region R1 in the oxygen gas supply unit 5 is At least upstream of the biomass supply device 2 is disposed.

  Furthermore, the oxygen gas supply unit 5 b corresponding to the first region R <b> 1 in the oxygen gas supply unit 5 is further arranged on the downstream side of the biomass supply device 2, and the water vapor supply unit 3 is upstream of any oxygen gas supply unit 5. Is located in

The synthesis gas and char and ash generated from biomass in the first region R1 rise to the second region R2 on the downstream side in the gas flow direction, and the above-described water gas shift reaction is promoted. The third oxygen gas supply unit 5 (5c) is disposed at the inlet of the second region R2 such that the tip is directed downward, and the oxygen gas supplied from the third oxygen gas supply unit 5 (5c) is used for water gas reaction. A part of the produced carbon monoxide burns.
CO + 1/2 · O ₂ → CO ₂

  Since the water gas shift reaction mainly performed in the second region is an exothermic reaction, the oxygen gas supplied from the third oxygen gas supply unit 5 (5c) is generated by the water gas reaction rather than maintaining the environmental temperature. The significance of adjusting the ratio of carbon oxide and hydrogen is significant. This is because the ratio of hydrogen gas increases as the amount of combustion of carbon monoxide increases.

  In addition, the water vapor | steam required for a water gas shift reaction is supplied from the water vapor | steam supply part 3, and the water vapor | steam which did not contribute to the water gas reaction in the 1st area | region is consumed. Further, since the oxygen gas supplied from the third oxygen gas supply unit 5 (5c) only burns to carbon dioxide, the gas flow rate rising up the reaction tower 4 does not change greatly.

  The gas and biomass or char or ash generated in the first region are configured to be movable between the first region R1 and the second region R2 via the communication portion 43.

  As described above, water necessary for the water gas reaction and the water gas shift reaction is supplied by the water vapor supplied from the water vapor supply unit 3, and the flow rate of water vapor is adjusted so that a spouted bed of biomass is formed in the first region. It is done.

  Specifically, a gas flow rate adjustment unit c that lowers the gas flow rate in the second region R2 than the gas flow rate in the first region R1 is formed in the communication unit 43. The gas flow rate adjusting unit c has an average cross-sectional area perpendicular to the internal gas flow (in FIG. 1, the area of the reaction tower in a plane perpendicular to the paper surface) larger in the second region R2 than in the first region R1. It is embodied by the shape of the reaction tower 4 in which the diameter is increased.

  This diameter expansion is carried out at an acute angle so that the gas flow from the first region R1 to the second region R2 is not disturbed, and the diameter is smoothly expanded without reducing the diameter, and so that biomass and residues are not deposited on the expanded portion. It is formed to stand up.

  When the gas generated in the first region R1 reaches the second region, the rising speed is reduced due to the shape of the reaction tower 4 formed to expand the diameter, and the unreacted biomass accompanying the gas is the weight of the biomass itself. It is set to fall into the first area. That is, most of the unreacted biomass becomes a raw material for the water gas reaction in the first region R1, or burns with oxygen gas and is ashed. When ashed, the specific gravity is reduced, and the residual residue of the ashed biomass is also rolled up in the spouted bed generated by the water vapor from the water vapor supply unit 3 and rises to the second region R2 along with the gas, and the exhaust port It is exhausted with gas from 40. Therefore, it is not necessary to provide a dedicated residual discharge unit for taking out the residue other than the exhaust port 40.

  Since the gas flow velocity adjusting unit c described above sufficiently reduces the flow velocity of the gas flowing through the second region R2, it is possible to secure a sufficient time for the water gas shift reaction. Therefore, it is not necessary to increase the length of the second region R2 so much that the reaction tower 4 can be made compact.

  As described above, the first region R1 in which the water gas reaction is mainly performed in the reaction tower 4 and the second region R2 in which the water gas shift reaction is mainly performed are formed along the gas flow. By discharging the ash from the second region, the first region R1 and the second region R2 are configured as one unit instead of separate devices, and a compact gasification furnace can be obtained.

The biomass supply apparatus 2 will be described in detail based on FIGS. 6 (a), (b), and (c).
As described above, the biomass supply device 2 has the casing 20 with the biomass inlet 22 formed on the proximal side and the tip side connected to the furnace wall of the gasification furnace 1, and the screw blades 21 inserted into the casing 20 , And is configured to transport and supply the biomass input to the biomass input port 22 to the inside of the gasification furnace 10 (reaction tower 4).

  As shown in FIG. 6A, on the base end side of the casing 20, the drive shaft of the electric motor 2d that rotationally drives the support shaft 2c that supports the screw blades 21 is connected via a speed reduction mechanism that includes gears and pulleys. ing.

  The screw blade 21 inserted in the casing 20 is rotated by the drive of the electric motor 2d, so that the biomass charged into the biomass charging port is pushed by the screw blade 21 and gradually moves in the casing 20, and the casing 20 Is conveyed and supplied into the furnace from the front end side.

  The volume of the section formed between one pitch of the casing 20 and the screw blades 21 along the transport direction is configured to be larger on the distal end side than on the proximal end side. Specifically, the pitch of the screw blade 21 is configured to be longer on the tip end side than on the base end side. You may be comprised so that the pitch of the screw blade | wing 21 may become long gradually from the base end side to the front end side. Further, the pitch may be increased stepwise by dividing the section. It is preferable that the pitch be increased from around the portion where the temperature is increased to 300 to 400 ° C. in the casing 20 where tar is likely to be generated.

  Biomass is filled and transported in a space defined by the casing 20 and the screw blades 21 and sealed so that outside air does not flow into the furnace by the biomass filled in the space. Since the volume per unit length is larger on the distal end side than on the proximal end side, the biomass in the casing 20 is transported from the consolidated state on the proximal end side to the distal end side, and is released and released. .

  The inside of the reaction tower 4 of the gasification furnace 1 is maintained at a high temperature of 500 ° C. or higher, and the tip side of the casing 20 is constantly exposed to a high temperature of 500 ° C. or higher. Where the temperature exceeds 300 to 400 ° C., the biomass is thermally decomposed to generate tar.

  Even if a portion of the biomass exposed to high temperature on the front end side of the casing 20 is pyrolyzed, the biomass is not so compacted, so that the tar generated by the pyrolysis enters the surrounding biomass before infiltrating the surrounding biomass. It will be transported. Moreover, even if some biomass gets wet with water vapor and adheres to the casing 20, it is conveyed into the furnace by the screw blades.

  The support shaft 2c of the screw blade 21 is configured to be shorter than the axial length of the screw blade 21, and a shaftless portion 2e lacking the support shaft 2c is formed on the distal end side of the screw blade 21.

  Therefore, the support shaft 2c of the screw blade 21 is not easily exposed to a high temperature, and it is not necessary to provide a special cooling mechanism on the support shaft 2c. Further, since the support shaft 2c becomes cooler than the surrounding atmosphere due to heat transfer, there is a risk of condensation or tar adhesion when it comes close to the reaction tower 4, but by providing the shaftless portion 2e, the adhesion area is reduced, and condensation or tar adheres. The risk of adhesion is reduced. Even if the screw blade 21 is provided with a cooling mechanism, the support shaft 2c is shortened, and the load on the cooling mechanism can be reduced. Since there is no support shaft 2c of the screw blade 21 on the front end side of the casing 20, the space of the casing 20 in which the biomass is conveyed becomes even wider on the front end side of the casing 20. Therefore, the consolidation of the biomass is further reduced.

  The tip of the screw blade 21 is formed to extend to the vicinity of the inner wall of the furnace wall. Therefore, even if tar generated by thermal decomposition of the biomass being transported adheres to the inner wall of the casing 20, it is scraped off by the outer periphery of the screw blade 21 and the biomass being transported without being solidified as it is in the furnace. Transported to If the tip of the screw blade 21 protrudes from the inside of the furnace wall, the inner wall of the casing 20 can be more reliably cleaned. However, the projecting and formed screw blade 21 is exposed to a temperature exceeding 500 ° C., so there is a high risk of damage, and the extension to the vicinity of the inner wall is better.

  As shown in FIG. 6B, the pitch of the screw blades 21 may be configured to be shorter at the intermediate portion 2i and longer at the distal end side than at the proximal end side. In the pitch shortening portion 2j on the base end side of the casing 20, the pitch is gradually shortened from the base end side of the casing 20 toward the front end side. On the other hand, in the shaftless portion 2e and the pitch extension portion 2h on the distal end side of the casing 20, the pitch is gradually increased from the proximal end side of the casing 20 toward the distal end side.

  Thereby, the filling rate of the biomass which moves in the casing 20 becomes small at the tip end side of the casing 20, and thereby, the unconsolidated biomass at the tip end side of the casing 20 is less likely to aggregate and adhere to the casing 20 and is stable. Can be supplied into the furnace. Furthermore, since the filling rate of the biomass in the intermediate part 2i of the casing 20 is larger than that on the base end side, the sealing effect is increased, and the inflow of outside air into the gasification furnace 1 and the gasification in the gasification furnace 1 are increased. The back flow of the agent can be suppressed.

  As shown in FIG.6 (c), you may comprise so that the diameter of the casing 20 and the screw blade | wing 21 may become large in the front end side compared with the base end side along a conveyance direction.

  According to this structure, it is possible to make the filling rate of the biomass conveyed in the casing 20 smaller on the distal end side than on the proximal end side of the casing 20 without changing the pitch of the screw blades. Thereby, at the base end side of the casing 20, the sealing performance is secured by the consolidated biomass, and at the same time, the unconsolidated biomass on the distal end side of the casing 20 is aggregated by tar or the like and hardly adheres to the casing 20. Can be stably supplied into the furnace.

  The outside of the furnace wall is covered with a heat insulating material. You may comprise so that the shaft-less part 2e which is the front end side from the spindle 2c among the screw blades 21 may be covered with a heat insulating material.

  By doing so, the support shaft 2c of the screw blade 21 is unlikely to become high temperature, and thereby the deterioration of the screw blade 21 can be suppressed. Further, since the support shaft 2c of the screw blade 21 is not covered with the heat insulating material, the load on the cooling mechanism can be reduced even when a cooling mechanism is provided on the support shaft 2c. As a cooling mechanism, there is a method of passing cooling water, cooling air or the like through the support shaft 2c or the screw blade 21.

  As shown in FIG. 3, the process control part 60 which manages and controls the biomass gasification process which progresses in the gasification furnace 10 mentioned above is further provided. The process control unit 60 includes a general purpose computer, a control program installed in the general purpose computer, and an expansion board. The expansion board includes a first temperature sensor S3 installed in the first region R1, a second temperature sensor S4 installed in the second region R2, a hydrogen gas sensor S1 installed in the exhaust pipe 42, and a carbon monoxide gas sensor S2. An input circuit to which a detection signal is input, a drive signal to a motor that rotationally controls the screw blades 21 of the biomass supply device 2, a control valve V1 that adjusts the flow rate of water vapor supplied from the water vapor source to the water vapor supply unit 3, and an oxygen gas source Is provided with an output circuit for outputting opening adjustment signals of the control valves Va, Vb, Vc for adjusting the amount of oxygen gas supplied to the oxygen gas supply units 5 (5a, 5b, 5c).

The process control unit 60 incorporates a supply amount adjustment mechanism 50 that individually adjusts and controls the supply amounts of oxygen gas supplied from the respective oxygen gas supply units 5 (5a, 5b, 5c). Based on the detection signals from the hydrogen gas sensor S1 and the carbon monoxide gas sensor S2 that measure the composition of the gas flowing out from the reaction tower 4, the supply amount adjusting mechanism 50 adjusts the gas composition to the target gas composition, that is, hydrogen and The supply amount of oxygen gas supplied from the oxygen gas supply unit 5 to each of the first region R1 and the second region R2 is adjusted so that the ratio H ₂ / CO of carbon monoxide is a desired ratio. ing.

As shown in FIG. 4 (a), the oxygen gas supplied from the first oxygen gas supply unit 5a provided in the first region R1 mainly burns the biomass, that is, compensates for the temperature lowered by the water gas reaction. It is spent burning solid carbon. The resulting combustion temperature raises the environmental temperature and promotes the water gas reaction, but the concentration of carbon monoxide CO and carbon dioxide CO ₂ generated by the combustion of solid carbon also increases, so it is relatively common with hydrogen The ratio of carbon oxide H ₂ / CO is reduced. This tendency becomes stronger as the amount of oxygen supplied from the first oxygen gas supply unit 5a increases.

  The oxygen gas supplied from the second oxygen gas supply unit 5b provided on the downstream side of the first region R1 is supplied in order to compensate for the temperature that decreases due to the water gas reaction generated on the upstream side. A mechanism similar to that of the oxygen gas supplied from the first oxygen gas supply unit 5a works, but the water gas shift reaction that occurs between carbon monoxide and water vapor that has already occurred in the water gas reaction is also promoted to some extent. That is, the balance between the combustion of solid carbon and the water gas shift reaction is adjusted by the amount of oxygen gas supplied from the second oxygen gas supply unit 5b.

As shown in FIG. 4 (b), the oxygen gas supplied from the third oxygen gas supply unit 5c provided in the second region R2 is mainly an oxidation caused by the water gas reaction performed in the first region R1. It is consumed for combustion of carbon CO or carbon monoxide CO generated by combustion reaction and water gas shift reaction. As a result, the environmental temperature rises and the water gas shift reaction is promoted. As a result, since the hydrogen gas H ₂ concentration is increased, the ratio H ₂ / CO of hydrogen and carbon monoxide is relatively increased. This tendency becomes stronger as the supply amount of oxygen is increased.

As shown in FIG. 4C, by adjusting the amount of oxygen gas supplied from the three systems of oxygen gas supply units 5 (5a, 5b, 5c), the ratio H ₂ / CO of hydrogen to carbon monoxide is calculated. It becomes possible to adjust to a desired ratio.

  Note that the area of the circle surrounding the gas composition shown in FIGS. 4A, 4 </ b> B, and 4 </ b> C indicates the approximate ratio of the generated gas.

  In FIG. 4 (d), as a result of variously adjusting the amount of oxygen gas supplied from the three oxygen gas supply units 5 (5a, 5b, 5c) using the gasification furnace 10 described above, The type and amount of gas produced is indicated.

  Run No. 1 shows the result of supplying the gas supply parts at an equal ratio with the total amount of oxygen gas supplied to the gasifier 10 being constant. 2 shows the result of supplying the supply amount to the third gas supply unit 5c so that the supply amount to the third gas supply unit 5c is relatively increased while the total amount of supply oxygen gas is constant. 3 shows the result of supplying the supply amount to the second gas supply unit 5b relatively increased with the total amount of supplied oxygen gas being constant. 4 shows the result of supplying the supply gas to the first gas supply unit 5a so that the supply amount is relatively increased while the total amount of supply oxygen gas is constant.

When attention is paid to the ratio H ₂ / CO of hydrogen and carbon monoxide, Run No. 2 which has a relatively large supply amount to the third gas supply unit 5c. 2, evenly supplied RunNo. The ratio H ₂ / CO is larger than that of Run No. 1, and the supply amount to the first gas supply unit 5a is relatively increased. 4, RunNo. It is confirmed that the ratio H ₂ / CO is smaller than that of Run No. 1, and the amount of supply to the second gas supply unit 5b is relatively increased. 3, evenly supplied RunNo. The ratio H ₂ / CO is smaller than that of RunNo. It can be confirmed that the same tendency as 4 appears.

  That is, the supply amount adjusting mechanism 50 maintains the total amount of oxygen gas supplied from the oxygen gas supply unit 5 so that the measured gas composition becomes the target gas composition, while maintaining the first region and the second region. Are configured to adjust the ratio of the supply amount supplied to each of.

Specifically, if the amount of oxygen gas supplied to the second region R2 is increased, the amount of H ₂ can be relatively increased, and the amount of oxygen gas supplied to the first region R1, more specifically, upstream of the first region R1. If the oxygen gas supply amount to the side is increased, CO can be relatively increased.

  For example, based on the biomass composition and moisture content, the amount of heat input is calculated by calculating the amount of heat input required to maintain the inside of the reaction tower 4 at the environmental temperature required to promote the water gas reaction and the water gas shift reaction. The total amount of oxygen gas is determined so as to be obtained by the combustion heat of biomass and / or the combustion heat of carbon monoxide for each region R1, R2, and while maintaining the determined total amount constant, The ratio of the supply amount supplied to each is adjusted.

  The supply amount adjusting mechanism 50 provided in the gasification furnace 10 according to the present invention has a first region R1 and / or a second region R2 detected by the first temperature sensor S3 and the second temperature sensor S4 in addition to the control mode described above. It is also possible to adjust the amount of oxygen gas supplied from each oxygen gas supply unit 5 (5a, 5b, 5c) so that the temperature becomes a predetermined environmental temperature. Also in this case, the amount of oxygen gas supplied from each oxygen gas supply unit 5 (5a, 5b, 5c) is adjusted so that the gas composition measured by the hydrogen gas sensor S1 and the carbon monoxide gas sensor S2 becomes the target gas composition. It is a prerequisite.

  Note that by increasing the number of temperature sensors and gas sensors, the amount of oxygen gas can be adjusted more accurately, and the ratio of temperature, hydrogen, and carbon monoxide can be adjusted with high accuracy.

  The process control unit 60 uses the biomass supply device when the supply amount adjusting mechanism 50 cannot control the gas composition to be the target gas composition, or when the gas amount decreases even when the gas composition reaches the target gas composition. The supply amount of biomass supplied from 2 and / or the supply amount of steam supplied from the steam supply unit 3 is adjusted to increase or decrease.

  The supply amount adjusting mechanism 50 is configured to adjust a necessary oxygen gas supply amount and a ratio of the supply amount based on fluctuations in the biomass supply amount and / or the water vapor supply amount.

When the gasification furnace according to the present invention is used, the ratio H ₂ / CO of hydrogen to carbon monoxide is approximately 2 by adjusting the amount of oxygen gas supplied from each oxygen gas supply unit 5 (5a, 5b, 5c). Or a synthesis gas having a hydrogen to carbon monoxide ratio H ₂ / CO of about 1.

Hereinafter, another embodiment of the gasifier according to the present invention will be described.
In the above-described embodiment, the example in which the reaction tower 4 is configured in a vertical cylindrical shape has been described. However, as long as the reaction tower 4 is vertical, an elliptical cylindrical shape or a rectangular cylindrical shape may be used.

  In the embodiment described above, a tapered portion that gradually increases in diameter from the first region R1 to the second region R2 is formed in the enlarged diameter portion that becomes the gas flow rate adjusting portion c formed in the communication portion 43. The angle is preferably formed as an obtuse angle. This is because when the diameter is rapidly expanded, a separation flow is generated, and ash or the like is accumulated in the step portion, which may hinder a decrease in the flow velocity.

  Although the above-described embodiment has been described with respect to the spouted bed type gasification furnace, it can also be applied to a fluidized bed type gasification furnace. Moreover, even if it is a spouted bed type gasification furnace, water gas reaction will be accelerated | stimulated by comprising so that silica sand and a ceramic particle may be mixed in a spouted bed slightly and biomass may be crushed with a spouted bed. .

  In the above-described embodiment, the example in which the heater, which is an external heat source, is used when the furnace is started up, but the heater, which is an external heat source, may be used to promote the water gas reaction. Even in this case, the power cost required for the heater can be significantly reduced by providing the oxygen gas supply unit.

  In addition, it is a better mode that the operation of the gasification furnace can be performed only by biomass without adding additional energy from the outside such as a heater which is an external heat source.

  In the embodiment described above, the example in which the gas supply mechanism 5 is configured by three systems has been described. However, as indicated by the broken line in FIG. 1, a gas supply mechanism 5d of another system may be further provided. Such a gas supply mechanism 5d may be provided not only in the first region R1 but also in the second region R2. By increasing the number of gas supply mechanisms, finer temperature adjustment in the reaction tower 4 and control of the component ratio of hydrogen and carbon monoxide can be achieved.

  In the above-described embodiment, oxygen gas is supplied vertically from one place of the peripheral wall of the reaction tower 4 from the first and second gas supply functions 5a and 5b, and oxygen gas is supplied from the third gas supply function 5c to the reaction tower 4. Although the aspect supplied to diagonally downward from one place of the surrounding wall was demonstrated, it is not restricted to such an aspect.

  For example, as shown in FIG. 5A, the gas supply mechanism 5 is provided with a header pipe 50 so as to surround the reaction tower 4, and the inner wall of the reaction tower 4 is formed from a plurality of gas supply pipes 51 formed in the header pipe 50. It may be configured to supply the gas in a direction in which a swirl flow is generated along with the gas, and a collision occurs from a plurality of gas supply pipes 51 toward the center of the reaction tower 4 as shown in FIG. You may comprise so that it may supply in direction to do.

  Further, as shown in FIGS. 5C and 5D, it may be configured to supply downward or upward with respect to the axial direction of the reaction tower 4. The mode of FIG. 5 (c) is the same as the third gas supply function 5c shown in FIG. 1, but this may be combined with the mode shown in FIGS. 5 (a) and 5 (b). The aspect of FIG.5 (d) is also the same, and becomes an especially suitable aspect for the 1st gas supply function 5a.

  As the oxygen gas supplied from the gas supply mechanism 5, for example, an oxygen-enriched gas obtained by adding oxygen to the atmosphere can be used in addition to a highly pure oxygen gas.

  In the embodiment described above, an example of using superheated steam at normal pressure has been described, but pressurized steam or saturated steam may be used. In the case of a normal pressure reaction tower as described above, normal pressure superheated steam may be considered in consideration of the expansion of steam inside the reaction tower and the cost of steam production.

  In the above-described embodiment, the aspect in which the inside of the reaction tower 4 is uniformly maintained at 500 ° C. or more has been described. In other words, the temperature distribution may be different between the first region R1 where the water gas reaction is mainly performed and the second region R2 where the water gas shift reaction is mainly performed. In this way, the temperature required for each reaction can be secured and energy consumption can be suppressed.

  In the above-described embodiment, a system for synthesizing liquid fuel by generating synthesis gas from biomass as raw material has been described. Any method may be used.

  In the above-described embodiment, the example in which the exhaust port 40 is provided at the top of the reaction tower 4 that connects to the space above the reaction tower 4 that is the second region has been described, but the exhaust port 40 may be connected to the second region. For example, it may be provided on the upper side of the reaction tower 4.

  In the embodiment described above, an example of using dry biomass such as rice straw, rice husk, wheat straw, corn stover and the like as raw material biomass has been described, but wood waste, bark, bamboo, or the like can also be used. By the way, rice husk has a specific gravity of about 0.1 and a water content of about 10%, bark has a specific gravity of about 0.6 and a water content of about 60%, bamboo has a specific gravity of about 0.7 and a water content of about 25%. It can cope with biomass.

  In the embodiment described above, the char generated from the gasification furnace is used for the water gas reaction in the gasification furnace, but as shown in FIG. 8, the char generated from the gasification furnace 10 is composed of a cyclone or the like. A waste heat boiler 203 that generates steam by heating the hot water with the heat stored in the synthesis gas is generated by separating it with the char separator 201 and generating hot water in a combustion furnace 202 using the separated char as fuel. The energy efficiency of the entire system may be improved, for example, by using the obtained water vapor in the gasification furnace 10. Reference numeral 204 denotes a gas purification apparatus, and reference numeral 205 denotes a power generation apparatus or an FT synthesis apparatus.

  The various embodiments described above are merely examples of the gasification furnace according to the present invention, and the scope of the present invention is not limited by the description. It is needless to say that change design can be made as appropriate as long as the effect is exhibited.

1: Gasification furnace 2: Biomass supply device 2c: Support shaft 2d: Electric motor 2e: Shaftless part 2h: Pitch extension part 2i: Intermediate part 2j: Pitch shortening part 3: Water vapor supply part 4: Reaction tower 5: Oxygen gas Supply part 5a: first oxygen gas supply part 5b: second oxygen gas supply part 5c: third oxygen gas supply part 10: gasification furnace 20: cylindrical casing 21: screw blade 40: exhaust port 43: communication part 101 : Cyclone 102: Scrubber 103: Activated carbon adsorption tower 104: FT synthesizer c: Gas flow rate adjusting unit H: Heater R 1: First region R 2: Second region

Claims (8)

An oxygen gas supply unit, a water vapor supply unit, and a biomass supply device are provided on a furnace wall, and a gasification furnace that causes a water gas reaction in the furnace,
The biomass supply apparatus includes a cylindrical casing having a biomass inlet formed on the proximal end side and a tip end connected to the furnace wall, and a screw blade inserted in the cylindrical casing, and the biomass injection The biomass introduced into the mouth is configured to be transported and supplied into the furnace, and the volume of the section formed between the cylindrical casing and one pitch of the screw blade along the transport direction is compared with the proximal end side A gasification furnace configured to be large on a tip side, wherein a support shaft of the screw blade is shorter than a length of the screw blade.   The gasifier according to claim 1, wherein the pitch of the screw blades is configured to be longer on the distal end side than on the proximal end side. Gasifier of claim 1 wherein being configured to be longer in shorter becomes the tip side at the intermediate portion pitch compared to the base end side of the front Symbol screw blade. The gasification furnace in any one of Claim 1 to 3 with which the front-end | tip of the said screw blade is extended and formed to the inner wall vicinity of the said furnace wall. The gasification furnace in any one of Claim 1 to 3 by which the front-end | tip of the said screw blade is protruded and formed inside the said furnace wall. Gasification furnace according to claim 1, diameter of the tubular casing and the screw blade along the conveying direction is configured to be larger at the distal end side as compared to the proximal side 5. The gasification furnace according to any one of claims 1 to 6 , wherein the furnace main body surrounded by the furnace wall is formed in a bowl shape, and the biomass supply device is connected to the furnace wall at a position above the water vapor supply unit. . The gasification furnace according to any one of claims 1 to 7 , wherein an outer side of the furnace wall is covered with a heat insulating material, and at least a tip side of the screw blade is covered with the heat insulating material from the support shaft.

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