JP2016190889A - Gasification furnace and method for operating the gasification furnace - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a simple gasification furnace with a high degree of freedom capable of obtaining a synthesis gas in a desired ratio while suppressing the utilization of an external heat source.SOLUTION: Provided is a gasification furnace comprising: a biomass feed part 20; a steam feed part 3; a reaction tower 4 formed with a first region R1 flowing a biomass fed from the biomass feed part in a jet floor formed by the stream fed from the stream feed part and a second region R2 in which the gas generated in the first region R1 flows along the flowing direction of the reaction gas; a plurality of oxygen gas feed parts 5 (5a, 5b, 5c) of feeding oxygen gas respectively to the first region R1 and the second region R2 in the reaction tower; a communication part 43 making the generated gas and the biomass or biomass residue movable between the first region R1 and the second region R2; and an exhaust port 40 of exhausting the generated gas and residue from the second region R2.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a gasification furnace for obtaining a gas as a raw material for energy from biomass, and a method for operating the gasification furnace.

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 attracting attention 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. Has been.

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

  Therefore, a configuration in which steam is heated and charged into the furnace, a gasification furnace is heated with an external heat source such as an electric heater, a configuration in which fossil fuel such as coal is input into the furnace as a heating source, or an oxygen in the furnace However, many problems still remain in terms of realizing an energy efficient gasification furnace, such as using a part of the combustion heat of biomass as a heating source.

  Patent Document 1 discloses a biomass gasification furnace that aims to provide a biomass gasification furnace that can perform clean and highly efficient gasification and achieve complete gasification of biomass.

The biomass gasification furnace includes biomass supply means for supplying a pulverized biomass having an average particle diameter of 0.05 ≦ D ≦ 5 mm, and combustion oxidant supply means for supplying a combustion oxidant of a mixture of oxygen and water vapor. The molar ratio of oxygen [O ₂ ] / carbon [C] is in the range of 0.1 ≦ O ₂ /C<1.0, and the molar ratio of water vapor [H ₂ O] / carbon [C] is 1 ≦ In a spouted bed gasification furnace having a H ₂ O / C range and a temperature of 700 to 1200 ° C., the combustion oxidant supply means has a plurality of stages so as to supply the combustion oxidant from a plurality of locations along the gas flow. It is provided and is configured to operate at a furnace pressure of 1 to 30 atmospheres. If the pressure in the furnace is 30 atm, the superficial velocity is lowered and the apparatus can be made compact.

  Also, the gasification furnace supplies coal as fossil fuel so as to form an auxiliary combustion part in the lower part of the furnace body, forms a high-temperature field by burning fossil fuel, and inputs biomass therein. And the aspect comprised so that pyrolysis gasification may be performed efficiently, without burning biomass is also disclosed.

  In Patent Document 2, for the same purpose as described above, gas is circulated inside from one side in the vertical direction to the other side, and a high-temperature reaction field is formed on the one side inside, and the one side inside and A gasification furnace body in which a gasification reaction field is formed with the other side, biomass supply means for supplying biomass to the high-temperature reaction field inside the gasification furnace body, and inside the gasification furnace body In a biomass gasification furnace comprising a combustion oxidant supply means for supplying oxygen to the high temperature reaction field and a steam supply means for supplying steam to the inside of the gasification furnace main body, the steam supply means comprises the gas A biomass gasification furnace configured to supply water vapor separately to the high temperature reaction field and the gasification reaction field inside the main body of the gasification furnace and operated at an internal pressure of 1 to 30 atm is disclosed. Yes.

  Patent Document 3 includes a plurality of gas supply units that supply an oxidizing gas containing oxygen and steam to the fluidized bed unit and the freeboard unit, respectively, and oxidizes biomass in the fluidized bed unit to 500 ° C to 750 ° C. A portion of the biomass oxidized in the previous stage is heated to a temperature of 800 ° C. to 850 ° C. on the upstream side of the free board part, and a part of the biomass oxidized in the previous stage is further 900 on the downstream side of the free board part. There is disclosed a fluidized bed type gasification furnace that is operated at a pressure in the furnace for generating synthesis gas by heating to a temperature of from 10000C to 1000C, at about 10 atm.

Japanese Patent No. 49389920 Japanese Patent No. 4388245 Japanese Patent No. 5576394

The gasification furnace disclosed in Patent Document 1 recognizes that the ratio H ₂ / CO of hydrogen gas to carbon monoxide gas does not exceed 2 when ordinary biomass is simply gasified. And a combustion oxidant supply means for supplying a combustion oxidant mixed with oxygen and water vapor so that the ratio H ₂ / CO of carbon monoxide gas to 2 or more necessary for methanol synthesis is provided upstream of the furnace, or upstream The oxygen [O ₂ ] / carbon [C] molar ratio is adjusted to a range of 0.1 ≦ O ₂ /C<1.0, and water vapor [H ₂ O] / This is a technique for adjusting the molar ratio of carbon [C] to a range of 1 ≦ H ₂ O / C, promoting water gas reaction with water vapor supplied from the combustion oxidant supply means, and simultaneously supplying water gas with oxygen supplied The carbon monoxide gas generated in the reaction is partially oxidized to form an aqueous gas. It is configured to maintain a suitable temperature 700 to 1200 ° C. the reaction.

In other words, the combustion oxidant is charged into the furnace and partially burned (CO + 1 / 2O ₂ → CO ₂ ) to be used as heat, and CO ₂ is removed in a subsequent process to remove [H ₂ O] / [CO]. The CO shift reaction apparatus which adjusts the composition of H ₂ and CO gas in the gas is provided separately at the rear stage of the gasification furnace.

Similarly to the gasification furnace disclosed in Patent Document 1, the gasification furnace disclosed in Patent Document 2 has a ratio H ₂ / CO of hydrogen gas to carbon monoxide gas of 2 or more necessary for methanol synthesis. This is a target gasification furnace. By supplying water vapor separately to the high temperature reaction field where the water gas reaction of the gasification furnace body and the gasification reaction field where the water shift reaction is performed, The yield of hydrogen gas is increased in the gasification reaction field while avoiding the temperature drop at

However, the fuel obtained by FT synthesis of the gas obtained by the water gas reaction is not limited to methanol, and the ratio H ₂ / CO of hydrogen gas to carbon monoxide gas must be adjusted to 2 or more without fail. There is nothing. For example, when synthesizing light oil from hydrogen gas and carbon monoxide gas using an iron-based catalyst, it is preferable to adjust the ratio H ₂ / CO of hydrogen gas to carbon monoxide gas to 1, but the same light oil is synthesized. Even in the case where the catalyst is different, the ratio H ₂ / CO between the preferred hydrogen gas and carbon monoxide gas becomes different. In such a case, the gasification furnace disclosed in Patent Documents 1 and 2 cannot be easily handled.

In addition, when the composition of the biomass as the raw material and the composition including the water content are different, the suitable conditions for the water gas reaction are also different, and the ratio H ₂ / CO of the generated hydrogen gas and carbon monoxide gas varies variously. flexible gasifier capable of obtaining the product gas in a ratio H _{2 /} CO to easily target in response to variations in the ratio H _{2 /} CO in the product gas to vary and objectives of the raw material has been desired .

  Furthermore, since the gasification furnaces disclosed in Patent Documents 1 and 2 are configured to supply oxygen gas and / or water vapor in multiple stages, the gas flow rate increases and the flow rate increases toward the downstream side. There is also a problem that the gasification furnace becomes large in order to ensure this. From such a viewpoint, the same applies to the gasification furnace disclosed in Patent Document 3.

  Since all the conventional gasification furnaces described above are furnaces operated by pressurization, it is necessary to ensure strict sealing performance, and there is a problem that equipment costs increase, and the operation is performed under atmospheric pressure or negative pressure. In some cases, there was a problem of further enlargement.

  Furthermore, although not described in detail in Patent Documents 1, 2, and 3, in order to keep the gasification furnace at a high temperature of 700 to 1200 ° C., it is heated by an external heat source such as a heater or combustion of fossil fuel such as coal. There is also a problem that it is necessary to consider global warming unlike carbon neutral biomass.

  An object of the present invention is to provide a simple gasification furnace having a high degree of freedom and a gasification furnace operation method capable of obtaining a desired ratio of synthesis gas while suppressing the use of an external heat source in view of the above-described problems. The point is to provide.

  In order to achieve the above-described object, the first characteristic configuration of the gasification furnace according to the present invention includes a biomass supply unit, a steam supply unit, and the steam supply as described in claim 1 of the claims. A first region in which the biomass supplied from the biomass supply unit flows in a spouted bed formed by water vapor supplied from the unit, and a second region into which the gas generated in the first region flows, A reaction tower formed along the flow direction, a plurality of oxygen gas supply sections for supplying oxygen gas to each of the first region and the second region of the reaction tower, and the generated gas and biomass or biomass residue It is in the point provided with the communicating part which can move between 1 area | region and 2nd area | region, and the exhaust port which discharges | emits the gas produced | generated from the 2nd area | region and residue.

  A spouted bed in which the biomass supplied from the biomass supply section flows with the steam supplied from the steam supply section is formed in the first region of the reaction tower, and the biomass is gasified while flowing in the first region, via the communication portion Then, it flows to the second region on the downstream side in the gas flow direction of the reaction tower. Biomass or part of the gas is combusted by supplying oxygen gas from the oxygen gas supply section provided in each of the first region and the second region, and the combustion heat is necessary for the gasification reaction in each region. At the same time it is used to ensure temperature, the gas component changes. Since the supply amount adjusting mechanism individually adjusts the oxygen gas supply amount to the first region and the oxygen gas supply amount to the second region, the temperature and the gas component in each region are adjusted, and as a result, the external The use of the heat source can be suppressed, and the components of the product gas can be adjusted in each region. The biomass supplied to the reaction tower is gasified into light ash and then exhausted from the exhaust port together with the gas.

  In the first region where the water gas reaction is mainly performed, a part of biomass mainly composed of carbon is burned and heated by the oxygen gas supplied from the oxygen gas supply unit, and the endothermic reaction is caused by the combustion temperature. A certain water gas reaction, that is, a reaction in which carbon monoxide gas and hydrogen gas are generated from carbon and water vapor is promoted. In the second region, the water gas shift reaction in which hydrogen gas is generated from the water vapor and carbon monoxide gas that have not contributed to the water gas reaction out of the water vapor supplied from the water vapor supply unit proceeds, and is supplied from the oxygen gas supply unit. Part of the carbon monoxide gas is burned by the oxygen gas. Thus, the first region where the water gas reaction is mainly performed in the reaction tower and the second region where the water gas shift reaction is mainly performed are formed along the gas flow, and the gasified lightweight ash is secondly formed. By discharging from the area, it becomes a compact gasifier.

  In the second feature configuration, in addition to the first feature configuration described above, the oxygen gas supply unit corresponding to the first region of the oxygen gas supply unit includes at least the oxygen gas supply unit. It exists in the point arrange | positioned upstream from a biomass supply part.

  The water gas reaction that occurs mainly between the biomass generated in the first region and the water vapor is an endothermic reaction, and the water gas reaction is suppressed when the temperature decreases due to the reaction. However, if the oxygen gas supply unit corresponding to the first region is disposed at least upstream of the biomass supply unit, the opportunity for contact between the biomass and oxygen gas increases, and the combustion reaction is likely to occur. Thereby, the combustion reaction is used as a heat source inside the reaction tower, and the use of the external heat source can be effectively suppressed.

  In the third feature configuration, in addition to the second feature configuration described above, the oxygen gas supply unit corresponding to the first region of the oxygen gas supply unit further includes It exists in the point arrange | positioned in the downstream of a biomass supply part.

  Since the carbon monoxide generated by the water gas reaction is combusted by the oxygen gas supplied from the downstream side of the biomass supply unit, the temperature decrease on the downstream side of the biomass supply unit is suppressed, and the water gas reaction is further promoted. Thus, the generated gas can flow down to the second region at a sufficient temperature.

  In the fourth feature configuration, in addition to any one of the first to third feature configurations described above, the reaction tower is vertical, and the second region is the first region. The water vapor supply unit is located upstream of the biomass supply unit.

  According to the above-described configuration, the upward flow of water vapor supplied from the water vapor supply unit acts on the biomass that is input to the reaction tower and falls downward, and effectively suppresses the biomass from falling to the bottom. A spouted bed of biomass is formed.

  In the fifth feature configuration, as described in claim 5, in addition to any of the first to fourth feature configurations described above, the gas flow rate in the second region is changed from the gas flow rate in the first region. Is also provided with a gas flow rate adjusting unit for reducing the gas flow rate.

  According to the above-described configuration, the gas flow rate in the second region is lower than the gas flow rate in the first region, and unreacted biomass having a large specific gravity that has not yet been gasified in the first region reaches the second region. It is not possible to stay and it is returned to the first area. The biomass returned to the first region will have another opportunity for a water gas reaction, a combustion reaction, etc., and will remain in the first region until it becomes biomass ash having a small specific gravity. Moreover, since the time required for the water gas shift reaction in the second region can be obtained, the gas flow direction size of the reaction tower can be reduced, and as a result, the conversion rate of biomass into the water gas reaction is also improved. Further, the residue having a small specific gravity cannot stay in the first region due to the flow velocity faster than that in the second region, moves to the second region, and is discharged from the exhaust port.

  In the sixth feature configuration, as described in claim 6, in addition to the fifth feature configuration described above, the gas flow velocity adjusting unit has an average cross-sectional area perpendicular to an internal gas flow in the first region. Further, the second region is embodied by the shape of the reaction tower formed to be larger.

  In the seventh feature configuration, in addition to the fifth or sixth feature configuration described above, the gas flow rate in the first region is set to a flow rate at which biomass floats, and The gas flow rate in the two regions is set to a flow rate at which biomass falls into the first region.

  According to the above-described configuration, the spouted bed of biomass is formed in the first region, and the water gas reaction is favorably promoted. Even if the unreacted and unreacted biomass of the water gas reaction reaches the second region, it cannot stay and falls to the first region, and an opportunity for the water gas reaction is obtained again. When the biomass is ashed by the water gas reaction, it is accompanied by the gas and flows down to the second region and is discharged from the exhaust port. Therefore, it is converted from biomass to gas at a high conversion rate in the first region.

  In the eighth feature, as described in claim 8, in addition to any one of the first to seventh features described above, each oxygen gas supply is based on the composition of the gas flowing out from the reaction tower. The supply amount adjustment mechanism for adjusting the supply amount of oxygen gas from the section is provided.

Based on the composition and supply amount of biomass supplied to the first region, that is, carbon C, hydrogen H, oxygen O and moisture H ₂ O contained in the biomass supplied to the reaction tower, water gas in the first region The degree of reaction, the degree of water gas shift reaction in the second region, and the amount of oxygen gas necessary to maintain the temperature in the region at that time at the desired temperature are calculated stoichiometrically by the supply amount adjusting mechanism, Since the supply amount of oxygen gas to be supplied from each oxygen gas supply unit is adjusted based on the result, a gas having a desired composition can be obtained with high efficiency while suppressing the use of an external heat source.

  In the ninth feature configuration, as described in claim 9, in addition to any one of the first to seventh feature configurations described above, the total oxygen gas is based on the composition of the gas flowing out from the reaction tower. A supply amount adjusting mechanism is provided that adjusts the ratio of the oxygen gas supply amount from each oxygen gas supply unit under a constant supply amount.

  According to the above-described configuration, the ratio of the gas supply amount from each oxygen gas supply unit is adjusted based on the composition of the gas flowing out from the reaction tower under a constant total supply amount of oxygen gas by the supply amount adjustment mechanism. Therefore, even if fluctuations occur in the composition or the like of the biomass, it becomes possible to flexibly cope with the synthesis gas having a desired composition with high accuracy.

  The first characteristic configuration of the gasification furnace operation method according to the present invention is the gasification furnace operation method having any one of the first to seventh characteristic configurations described above. The oxygen gas supplied to each of the first region and the second region from the oxygen gas supply unit so that the composition of the gas flowing out from the reaction tower is measured and the measured gas composition becomes the target gas composition The amount of supply is adjusted.

  As described in claim 11, the second characteristic configuration is a gasification furnace operating method having any one of the first to eighth characteristic configurations in addition to the first characteristic configuration described above. And supplying each of the first region and the second region while keeping the total amount of oxygen gas supplied from the oxygen gas supply unit constant so that the measured gas composition becomes the target gas composition. The oxygen gas supply amount ratio is adjusted.

  As described above, according to the present invention, there is provided a simple gasification furnace having a high degree of freedom and a gasification furnace operating method capable of obtaining a desired ratio of synthesis gas while suppressing the use of an external heat source. I was able to do it.

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). Illustration 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. Explanatory diagram of a biomass liquid fuel system incorporating a gasifier according to the present invention Explanatory drawing of the energy generation system incorporating the gasification furnace by this invention

Hereinafter, embodiments of the gasification furnace and the operation method of the gasification furnace according to the present invention will be described.
As shown in FIG. 6, 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 from 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 includes a reaction tower that generates synthesis gas (H ₂ , CO) by reducing and heating biomass with steam or superheated steam 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 subsequent stage, and after impurities are removed, it is heated and pressurized to high temperature and high pressure via a heater and a compressor, and is introduced into the FT synthesis device 104.

FT synthesis is an abbreviation for Fischer-Tropsch synthesis and refers to a series of synthetic reaction processes in which liquid hydrocarbons are synthesized from carbon monoxide and hydrogen using a 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. For example, in the case of synthesizing methanol, it may be preferable that the ratio of hydrogen to carbon monoxide H ₂ / CO is about 2 although it varies depending on the type and properties of the catalyst. 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 a desired hydrocarbon in the FT synthesis, it is preferable that the ratio H ₂ / CO of hydrogen and carbon monoxide is adjusted, and this ratio is FT even when the same kind of hydrocarbon is obtained. It also depends on the type of catalyst used in the synthesis.

Accordingly, a highly versatile gasification furnace 10 that can obtain synthesis gas at various ratios H ₂ / CO is desired, and a compact gasification furnace 10 that has a high synthesis gas yield 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 and is a vertical cylindrical reaction tower 4 made of a corrosion-resistant metal, a biomass supply device 2 that supplies 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. The gas is led to the gas purification device 204 (see FIG. 6) 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 raising the reaction tower 4. The gas purification apparatus 204 (see FIG. 6) 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. 6). And purified.

  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. A biomass inlet 22 is provided on 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 charged into the charging port 22 is conveyed compactly by the screw blades 21 and charged into the reaction tower 4. That is, the space between the outside air and the inside of the reaction tower 4 is sealed with the biomass that is filled and consolidated in 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.

  In the reaction tower 4, a heat insulating wall W is installed 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 unit 2 to the inside of the reaction tower 4 is generated by the steam injected from the nozzle 30 provided at the tip of the water vapor supply unit 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 at the lower part of the reaction tower 4 is formed is a first region R1 where 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 unit 2 in the first region R1, and the biomass is partially burned 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 unit 2, and the water vapor supply unit 3 is upstream of any oxygen gas supply unit 5. Is arranged.

The synthesis gas, char and ash generated from the biomass in the first region R1 rise to the second region R2 on the downstream side in the gas flow direction, and the water gas shift reaction described above 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 proportion of hydrogen gas increases as the combustion amount 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. Has been.

  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. This is embodied by the shape of the reaction tower 4 having an enlarged diameter.

  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 40 is exhausted together with the gas. 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, and the reaction tower 4 can be configured compactly.

  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.

  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 controls rotation of the screw blades 21 of the biomass supply unit 2, a control valve V1 that adjusts a flow rate of water vapor supplied from the water vapor source to the water vapor supply unit 3, 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 amount of oxygen gas supplied from each oxygen gas supply unit 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 oxygen gas supply amount 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 carbon monoxide ratio H ₂ / CO becomes a desired ratio. ing.

As shown in FIG. 4A, the oxygen gas supplied from the first oxygen gas supply unit 5a provided in the first region R1 mainly burns biomass in order to compensate for the temperature that decreases due to the water gas reaction. It is spent burning solid carbon. The resulting combustion temperature increases 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 that it is relatively equal to 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. 4B, the oxygen gas supplied from the third oxygen gas supply unit 5c provided in the second region R2 is mainly oxidized 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. 4 (c), 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 reduced. The desired ratio can be adjusted.

  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.

  RunNo. 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. It is comprised so that the ratio of the supply amount supplied to each of these may be adjusted.

  Specifically, when the amount of oxygen gas supplied to the second region R2 is increased, hydrogen can be relatively increased, and the amount of oxygen gas supplied to the first region R1, more specifically, upstream of the first region R1. When the amount of oxygen gas supplied is increased, carbon monoxide 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 is configured to supply the biomass supply unit when the gas amount cannot be controlled by the supply amount adjusting mechanism 50 so that the gas composition becomes 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.

  As described above, by using the gasification furnace 10 of the present invention, water vapor is supplied to the biomass on the upstream side of the reaction tower to form a spouted bed, and a water gas reaction promotion step that mainly promotes a water gas reaction; For the gas produced in the water gas reaction step, oxygen gas is supplied to each of the water gas shift reaction promotion step for promoting the water gas shift reaction mainly on the downstream side of the reaction tower, the water gas reaction promotion step, and the water gas shift reaction promotion step. A biomass gasification method including an oxygen gas supply step of adjusting the composition of the gas flowing out from the reaction tower by adjusting the ratio of the oxygen gas supplied to each of them is supplied.

  In the oxygen gas supply step, the ratio of the supply amount is adjusted while maintaining the total amount of oxygen gas supplied to each of the water gas reaction promotion step and the water gas shift reaction promotion step, so that the gas flowing out of the reaction tower A step of adjusting the composition is included.

When the gasification furnace according to the present invention is used, the ratio H ₂ / CO of hydrogen to carbon monoxide is about 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 diagonally downward from one place of a 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. However, the temperature distribution in the reaction tower 4 is adjusted according to the temperature required for each of the water gas reaction and the water gas shift reaction. 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 embodiment described above, the system for synthesizing liquid fuel by generating synthesis gas from biomass as raw material has been described. However, the synthesis gas purified by the gasification furnace can be used as gas fuel for power generation and the like. 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 above-described embodiment, 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 above-described embodiment, the char generated from the gasification furnace is used for the water gas reaction in the gasification furnace, but as shown in FIG. 7, 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. You may make it improve energy efficiency as the whole system, such as utilizing the produced water vapor for the gasification furnace 10. Reference numeral 204 denotes a gas purification device, and reference numeral 205 denotes a power generation device or an FT synthesis device.

  The various embodiments described above merely describe one specific example of the gasification furnace, the operation method of the gasification furnace, and the biomass gasification processing method according to the present invention, and the scope of the present invention is limited by the description. It is needless to say that the specific configuration of each part can be appropriately changed and designed within the range where the effects of the present invention can be achieved.

2: biomass supply unit 3: steam supply unit 4: reaction tower 5: oxygen gas supply unit 5a: first oxygen gas supply unit 5b: second oxygen gas supply unit 5c: third oxygen gas supply unit 10: gasifier 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 adjustment part H: Heater R1: 1st area | region R2: 1st 2 areas

Claims (11)

A biomass supply department;
A water vapor supply unit;
A first region in which the biomass supplied from the biomass supply unit flows in a spouted bed formed by water vapor supplied from the water vapor supply unit, and a second region into which the gas generated in the first region flows. A reaction tower formed along the gas flow direction;
A plurality of oxygen gas supply units for supplying oxygen gas to each of the first region and the second region of the reaction tower;
A communication part that allows the generated gas and biomass or biomass residue to move between the first region and the second region;
An exhaust port for discharging the gas and residue generated from the second region;
Gasification furnace equipped with.   2. The gasifier according to claim 1, wherein an oxygen gas supply unit corresponding to the first region in the oxygen gas supply unit is disposed at least upstream of the biomass supply unit.   The gasifier according to claim 2, wherein an oxygen gas supply unit corresponding to the first region in the oxygen gas supply unit is further arranged on a downstream side of the biomass supply unit.   The gas according to any one of claims 1 to 3, wherein the reaction tower has a vertical shape, the second region is formed above the first region, and the water vapor supply unit is disposed upstream of the biomass supply unit. Chemical reactor.   The gasification furnace in any one of Claim 1 to 4 provided with the gas flow rate adjustment part which makes the gas flow rate of the said 2nd area | region lower than the gas flow rate of the said 1st area | region.   The gas flow rate adjusting unit is embodied by a shape of the reaction tower formed such that an average cross-sectional area orthogonal to an internal gas flow is larger in the second region than in the first region. 5. The gasification furnace according to 5.   The gasification furnace according to claim 5 or 6, wherein the gas flow rate in the first region is set to a flow rate at which biomass floats, and the gas flow rate in the second region is set to a flow rate at which biomass falls into the first region.   The gasifier according to any one of claims 1 to 7, further comprising a supply amount adjusting mechanism for adjusting an oxygen gas supply amount from each oxygen gas supply unit based on a composition of a gas flowing out from the reaction tower.   2. A supply amount adjusting mechanism for adjusting a ratio of oxygen gas supply amounts from the respective oxygen gas supply units under a constant total supply amount of oxygen gas based on a composition of gas flowing out from the reaction tower. 8. A gasifier according to any one of 7 above. A method for operating a gasifier according to any one of claims 1 to 8,
Measuring the composition of the gas flowing out of the reaction tower;
An operation method of a gasification furnace in which an oxygen gas supply amount supplied from the oxygen gas supply unit to each of the first region and the second region is adjusted so that a measured gas composition becomes a target gas composition.   The oxygen gas supplied to each of the first region and the second region is kept constant while maintaining the total amount of oxygen gas supplied from the oxygen gas supply unit so that the measured gas composition becomes the target gas composition. The operation method of the gasification furnace of Claim 10 which adjusts the ratio of supply amount.

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