JP4997546B2 - Supercritical water biomass gasifier and system including the same - Google Patents

Description

  The present invention relates to a fluidized bed reactor for gasifying biomass with supercritical water, and a system including the same.

In recent years, energy conversion technology using biomass such as plants or waste materials thereof, livestock excrement, food waste, food waste, and sewage sludge has been developed. As an energy conversion technology using biomass as a raw material, for example, a method of fermenting biomass with microorganisms to generate fuel gas, a method of generating pressurized fuel water using water contained in biomass, and generating fuel gas As the latter improvement method, a method of gasifying wet biomass (hydrous biomass) with supercritical water using a catalyst to generate fuel gas such as hydrogen and methane is known. (For example, see Patent Documents 1 to 3).
Japanese National Patent Publication No. 11-502891 JP 2002-105466 A JP 2002-105467 A

  However, the supercritical water gasification technology known so far is not always satisfactory in terms of the generation efficiency of fuel gas, and the development of a technology that can generate fuel gas more efficiently from biomass has been developed. It has been demanded.

  Then, an object of this invention is to provide the supercritical water gasification technique which can produce | generate fuel gas, such as methane and hydrogen, more efficiently from biomass.

  In order to solve the above-described problems, a biomass gasification system using supercritical water according to the present invention has a biomass temperature of 100 to 250 ° C. and 0.1 to 4 MPa in the presence of a nonmetallic catalyst. And a biomass slurry containing the nonmetallic catalyst obtained by hydrothermal treatment in the pretreatment apparatus under the condition of pressure within a range of 374 ° C. or higher. And a fluidized bed reactor that performs hydrothermal treatment under conditions of a pressure of 22.1 MPa or more, and the fluidized bed reactor introduces the slurry into the fluidized bed reactor from below. A product gas and ash generated by hydrothermal treatment in the fluidized bed reactor, a discharge port for discharging the non-metallic catalyst and water from above to the fluidized bed reactor, and the soot. A fluidized medium that forms a fluidized bed in the fluidized bed reactor by introducing a Lie body; and a dispersion unit that disperses the slurry introduced from the inlet under the fluidized bed. Is formed in a shape that is not discharged at the introduction speed of the slurry body.

  The system described above includes the product gas, the ash, the nonmetallic catalyst, and the water discharged from the fluidized bed reactor, the product gas, the ash, the nonmetallic catalyst, and water. You may further provide the gas-liquid separation apparatus isolate | separated into the liquid mixture containing. Furthermore, the above-described system may further include means for recovering the nonmetallic catalyst in the mixed solution.

  The system described above further includes a heating device that heats the fluidized bed reactor using a part of the product gas, a crusher that crushes the biomass that is hydrothermally treated in the pretreatment device, and the like. May be.

  Furthermore, the system described above includes means for supplying the slurry body hydrothermally treated in the fluidized bed reactor to the fluidized bed reactor, and the product gas, the ash content, and the nonmetal discharged from the outlet. It is good also as a heat exchanger which preheats the said slurry body supplied to the said fluidized bed reactor using the heat | fever of the waste containing a system catalyst and water. Further, the system described above is configured to supply the biomass to be subjected to hydrothermal treatment in the pretreatment device to the pretreatment device and the biomass to be supplied to the pretreatment device using heat of the slurry body. It is good also as including the heat exchanger which pre-heats. Furthermore, the system described above includes means for supplying the biomass to be subjected to hydrothermal treatment in the pretreatment device to the pretreatment device, the produced gas, the ash content, and the nonmetallic catalyst discharged from the discharge port. And a heat exchanger that preheats the biomass supplied to the pretreatment device by using the heat of the discharge containing water.

  The hydrothermal treatment in the pretreatment device is preferably performed under conditions of a predetermined pressure and a saturation temperature of water at the pressure, and the hydrothermal treatment in the fluidized bed reactor is performed at a temperature of 600 ° C. It is preferable to carry out under the condition of a pressure of 25 MPa.

  Further, the supercritical water biomass gasification apparatus according to the present invention is an apparatus for gasifying biomass with supercritical water, and introduces the biomass slurry containing non-metallic catalyst into the apparatus from below. And a product gas and an ash produced by hydrothermally treating the slurry body in the apparatus at a temperature of 374 ° C. or higher and a pressure of 22.1 MPa or higher, and the nonmetallic catalyst and A discharge port for discharging water from above to the outside of the apparatus, a fluid medium for forming a fluidized bed in the apparatus by introduction of the slurry body, and the slurry body introduced from the inlet are disposed below the fluidized bed. A dispersion section that disperses the fluid medium, and the fluid medium has a shape that is not discharged at the introduction speed of the slurry body.

  The hydrothermal treatment is preferably performed under conditions of a temperature of 600 ° C. and a pressure of 25 MPa.

  The fluid medium is, for example, an alumina ball. The dispersion part may be a layer formed by stacking alumina balls, for example. As the non-metallic catalyst, for example, activated carbon can be used. The activated carbon is preferably in a powder form and has an average particle size of 200 μm or less.

  ADVANTAGE OF THE INVENTION According to this invention, the supercritical water gasification technique which can produce | generate fuel gas, such as methane and hydrogen, more efficiently from biomass can be provided.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings.

== Overall Configuration of Biomass Gasification System Using Supercritical Water of the Present Invention ==
FIG. 1 is a diagram showing a schematic configuration of a biomass gasification system using supercritical water described as an embodiment of the present invention. As shown in FIG. 1, a biomass gasification system (hereinafter simply referred to as “system”) 100 using supercritical water according to the present invention includes a crushing pump 10, a water tank 11, a Mono pump 20, and a first heat exchanger 30. , Second heat exchanger 31, pretreatment device 40, slurry supply device 50, fluidized bed reactor 60, cooler 70, decompressor 71, gas-liquid separator 80, gas tank 81, solid-liquid separator 82, burner 90, etc. Prepare.

  The pretreatment device 40 is a device for forming a biomass slurry. The biomass slurry is formed by hydrothermal treatment of biomass in the presence of a nonmetallic catalyst under conditions of a temperature in the range of 100 to 250 ° C. and a pressure in the range of 0.1 to 4 MPa. Is done.

  The MONO pump 20 is a device that transfers a mixed solution containing a nonmetallic catalyst, biomass, and water, prepared to a predetermined moisture content, to the pretreatment device 40.

  The crushing pump 10 crushes the biomass hydrothermally treated by the pretreatment device 40 in advance to a uniform size (preferably an average particle size of 500 μm or less, more preferably an average particle size of 300 μm or less). It is a device to transfer. The biomass crushed by the crushing pump 10 is transferred to the MONO pump 20 together with the nonmetallic catalyst.

  The water tank 11 is a container for storing water to be mixed with a mixture of biomass crushed by the crushing pump 10 and a nonmetallic catalyst. Water is supplied from the water tank 11 and mixed with a mixture of the biomass crushed by the crushing pump 10 and the nonmetallic catalyst, whereby a mixed liquid prepared to have a predetermined moisture content is produced.

  The fluidized bed reactor 60 is a device that gasifies biomass with supercritical water. Biomass gasification with this supercritical water is a process of hydrothermally treating the biomass slurry containing a nonmetallic catalyst in the pretreatment device 40 at a temperature of 374 ° C. or higher using the nonmetallic catalyst. And hydrothermal treatment under conditions of a pressure of 22.1 MPa or more. By treating the slurry body with supercritical water in this way, biomass is decomposed and fuel gas such as hydrogen gas, methane, ethane, and ethylene is generated.

  FIG. 2 shows a schematic configuration diagram of a fluidized bed reactor 60 described as one embodiment of the present invention. As shown in FIG. 2, the fluidized bed reactor 60 includes an inlet 210 for introducing a biomass slurry body containing a nonmetallic catalyst into the apparatus 60 from below, and the slurry body within the apparatus 60 at 374 ° C. or higher. The generated gas containing fuel gas and ash produced by hydrothermal treatment under the temperature of 22.1 MPa or higher, and the ash, and the nonmetallic catalyst and water (supercritical water) from above the apparatus 60 A discharge port 220 for discharging the fluid, a fluid medium 230 for forming a fluidized bed in the apparatus 60 by introduction of the slurry body, and a dispersion unit 240 for dispersing the slurry material introduced from the inlet 210 below the fluidized bed. ing.

  The fluid medium 230 has a shape that is not discharged at the introduction speed of the slurry body, for example, a fluidized bed is formed at the speed at which the slurry body is introduced from the introduction port 210, but the weight that cannot be discharged from the discharge port 220, In the case where a plate-like plate is installed, the plate has a size larger than the mesh of the plate. The fluid medium 230 is not particularly limited as long as the particle diameter is not easily broken even in a supercritical state, and examples thereof include media such as alumina balls, zirconia balls, and silica balls.

  The dispersion unit 240 may be, for example, a known dispersion plate used in a fluidized bed reactor or the like. However, in order to prevent an increase in pressure due to clogging of the slurry body, the dispersion part 240 flows at a speed at which the slurry body is introduced. It is preferable that the layer is formed by stacking spherical media (for example, spherical media such as alumina balls) configured in a shape that does not.

  Using the fluidized bed reactor 60 as described above, the slurry introduced from the inlet 210 is gasified with supercritical water using a non-metallic catalyst contained therein, and the generated gas (fuel) Gas) and ash, and non-metallic catalyst and water (supercritical water) such as water (supercritical water) can be discharged from the discharge port 220. With such a configuration, the fluidized bed reactor 60 according to the present invention can suppress accumulation of ash, nonmetallic catalyst, and the like in the fluidized bed reactor 60. It becomes possible to perform a process of continuously gasifying the contained slurry body of biomass with supercritical water.

  The slurry supply device 50 is a device that supplies a biomass slurry containing a nonmetallic catalyst, obtained by performing hydrothermal treatment in the pretreatment device 40, to the fluidized bed reactor 60. The slurry supply device 50 is not particularly limited as long as it is a device that can supply a biomass slurry including a nonmetallic catalyst. For example, a high-pressure pump or a Mono pump can be used.

  The cooler 70 is a device that cools the discharge discharged from the fluidized bed reactor 60. The exhaust discharged from the fluidized bed reactor 60 contains explosive fuel gas (for example, hydrogen, methane, ethane, ethylene, etc.), water vapor (supercritical water), etc., thus reducing the risk. The cooler 70 is provided in the system 100 of the present invention for the purpose of causing the water vapor to be converted into water. In the present embodiment, the cooler 70 has been described as an example of a device for cooling the discharge discharged from the fluidized bed reactor 60. However, the discharge discharged from the fluidized bed reactor 60 is cooled. Any device can be used as long as it can be used.

  The decompressor 71 is a device that reduces the pressure of the product gas or the like in the exhaust discharged from the fluidized bed reactor 60. As a result, the danger of the product gas due to the high pressure can be prevented beforehand.

  The gas-liquid separator 80 separates the effluent discharged from the outlet 220 of the fluidized bed reactor 60 into a gas component (product gas) and a liquid component (mixed liquid containing ash, nonmetallic catalyst, and water). It is a device to do. As the gas-liquid separator 80, for example, an existing gas-liquid separator such as a separator can be used.

  The gas tank 81 is a container (preferably a pressure resistant container) that stores the gas component (product gas) separated by the gas-liquid separator 80. The burner 90 is a device that heats the fluidized bed reactor 60 using a part of the product gas (fuel gas) stored in the gas tank 81. In the present embodiment, the burner 90 is described as an example of a device for heating the fluidized bed reactor 60. However, any device that can heat the fluidized bed reactor 60 is used. It may be used.

  The solid-liquid separator 82 may be an existing device that separates the mixed liquid containing the ash, the nonmetallic catalyst, and water separated by the gas-liquid separator 80 into a solid component and a liquid component, The apparatus which isolate | separates the ash in a liquid mixture, a nonmetallic catalyst, and water may be sufficient, respectively. In FIG. 3, the schematic block diagram of the solid-liquid separator 82 which isolate | separates the ash content in a liquid mixture, a nonmetallic catalyst, and water each demonstrated as one Embodiment of this invention is shown. In the present embodiment, the case where the nonmetallic catalyst is activated carbon having a lower sedimentation rate (termination rate) than ash will be described.

  As shown in FIG. 3, the solid-liquid separator 82 includes a mixed liquid injection unit 310, a water tank 320, a circulation pump 330, a supply pipe 340, an ash receiving unit 350, valves 360, 361, and 370.

  The mixed liquid injection unit 310 is a tube for injecting a mixed liquid containing ash, activated carbon, and water from the gas-liquid separator 80. The water tank 320 is a container in which water for slowly settling ash and activated carbon in the liquid mixture injected from the liquid mixture injection unit 310 is placed. The water tank 320 has a discharge port 321 for allowing the ash content in the liquid mixture injected from the liquid mixture injection section 310 to settle and discharge it from the water tank 320, an activated carbon receiving part 322 323 for receiving activated carbon in the liquid mixture, And a drain outlet 324 for discharging floating substances such as activated carbon with water.

  The ash receiving unit 350 is a container that receives the ash that has settled from the discharge port 321. The circulation pump 330 is a pump that circulates the water in the water tank 320. The supply pipe 340 is a pipe that introduces water circulated by the circulation pump 330 into the water tank 320 through the discharge port 321. The water circulated by the circulation pump 330 is supplied from the discharge port 321 to the water tank 320 at a flow rate that is faster than the sedimentation rate of activated carbon and slower than the sedimentation rate of ash. Thereby, the ash in the mixed liquid injected from the mixed liquid injection unit 310 settles in the ash receiving unit 350 through the discharge port 321, but the activated carbon in the mixed liquid injected from the mixed liquid injection unit 310 is It moves to the activated carbon receiving parts 322 and 323 without passing through the discharge port 321.

  In the present embodiment, the activated carbon receiving portions 322 and 323 are provided with ridges 325 and 326 made of finer mesh than the activated carbon particles so that the activated carbon collected in the receiving portions 322 and 323 can be collected. The ash receiving part 350 is provided with a ridge 351 made of a mesh finer than the ash particles so that the ash collected in the receiving part 350 can be collected.

  The valves 360 and 361 are valves that discharge water from the water tank 320. After separating the ash and activated carbon in the mixed liquid injected from the gas-liquid separator 80, the activated carbon accumulated in the tanks 325 and 326 is recovered by draining the water in the water tank 320 through the valves 360 and 361. Can do. The valve 370 is a valve for draining water from the ash receiving unit 350. After separating the ash and activated carbon in the liquid mixture injected from the gas-liquid separator 80, the ash collected in the tub 351 can be recovered by draining the water in the ash receiving part 350 by the valve 370. .

  By providing the above-described solid-liquid separator 82 in the system 100 of the present invention, not only the mixed liquid is separated into the solid component and the liquid component, but also the ash that is the solid component and the nonmetallic catalyst are separated. And non-metallic catalyst can be recovered. Thereby, the recovered nonmetallic catalyst can be reused.

  Note that the system 100 according to the present invention includes a solid-liquid separator 82 that separates a mixed liquid containing ash, a nonmetallic catalyst, and water separated by the gas-liquid separator 80 into a solid component and a liquid component. In this case, the system 100 according to the present invention may further include a device (for example, a sieving device) that separates the ash content in the separated solid component from the nonmetallic catalyst. Thereby, the nonmetallic catalyst used for each reaction can be recovered and reused.

  The first heat exchanger 30 is supplied from the MONO pump 20 to the pretreatment device 40 using the heat of the biomass slurry containing the nonmetallic catalyst obtained by the hydrothermal treatment by the pretreatment device 40. This device preheats biomass.

  The second heat exchanger 31 uses the heat of the exhaust discharged from the fluidized bed reactor 60 to introduce biomass slurry containing a nonmetallic catalyst, which is introduced into the fluidized bed reactor 60 from the slurry supply device 50. This is a device for preheating.

  As described above, by providing the heat exchangers 30 and 31 in the system 100 of the present invention, energy can be used effectively, so that fuel gas can be generated from biomass at low energy and low cost. become. Moreover, since the heating time in each apparatus 40 and 60 is shortened, fuel gas can be efficiently generated from biomass. Therefore, it can be said that the system 100 including the heat exchangers 30 and 31 is excellent in economic efficiency.

  In the present embodiment, the system 100 of the present invention includes the second heat exchanger 31 that preheats the slurry using the heat of the exhaust discharged from the fluidized bed reactor 60. The system 100 of the present invention may be provided with a heat exchanger that preheats biomass or the like supplied from the mono pump 20 to the pretreatment device 40 using the heat of the exhaust discharged from the fluidized bed reactor 60. .

  As described above, by providing the fluidized bed reactor 60 as described above in the system 100 according to the present invention, ash (residue) obtained by gasifying biomass with supercritical water is contained in the fluidized bed reactor 60. Therefore, it is possible to continuously perform the gasification treatment of biomass with supercritical water, and to generate fuel gas from biomass more efficiently.

  Moreover, since biomass can be decomposed | disassembled into a low molecule from a polymer by providing the system 100 which concerns on this invention with the pre-processing apparatus 40 which carries out the hydrothermal treatment of biomass beforehand, the biomass processed in the fluidized bed reactor 60 The contact efficiency between water and water or non-metallic catalysts is increased, char and tar are prevented from being generated, and fuel gas can be efficiently generated from biomass.

  Furthermore, since the biomass slurry body excellent in fluidity can be formed by hydrothermally treating the biomass in the pretreatment device 40, the slurry can be obtained by using the slurry supply device 50 such as an existing high-pressure pump or a Mono pump. The body can be supplied to the fluidized bed reactor 60, and clogging of equipment, piping and the like due to biomass can be prevented in the supply to the fluidized bed reactor 60.

  In addition, the non-metallic catalyst used in the hydrothermal treatment in the pretreatment device 40 can be used in the hydrothermal reaction in the fluidized bed reactor 60 by the system 100 according to the present invention. Can be reduced.

  Furthermore, by providing the system 100 according to the present invention with the cooler 70, the pressure reducer 71, the gas-liquid separator 80, etc., the produced gas containing the fuel gas can be safely recovered from the exhaust gas discharged from the fluidized bed reactor 60. Will be able to.

  In addition, since the biomass can be crushed in advance by providing the system 100 according to the present invention with a device (crushing pump 10) for crushing biomass, it is possible to increase the efficiency of biomass slurrying and gasification. .

  Furthermore, since electric power and exhaust heat can be obtained by performing power generation with a gas engine using the fuel gas obtained by the system 100 according to the present invention, resource saving of fossil fuels such as coal and oil is achieved. It becomes possible.

  In the present embodiment, the mixture obtained by mixing the nonmetallic catalyst and the biomass from the beginning is processed by the crushing pump 10 and supplied to the pretreatment device 40 by the MONO pump 20, but the nonmetallic catalyst is Although it is good also as supplying to the pre-processing apparatus 40 separately from biomass, before processing with the pre-processing apparatus 40 after processing with the crushing pump 10, mixing with biomass and supplying to the pre-processing apparatus 40 It is good.

  In the present embodiment, the biomass slurry containing the non-metallic catalyst that has been hydrothermally treated in the pretreatment device 40 is directly supplied to the fluidized bed reactor 60 using the slurry supply device 50. However, the slurry body may be preheated by a heating device (for example, a heater or the like) before being supplied to the fluidized bed reactor 60.

== Biomass gasification method using supercritical water ==
Next, as one embodiment of the present invention, a method for generating fuel gas from biomass will be described.

  First, the biomass in the mixture obtained by mixing the biomass and the nonmetallic catalyst is transferred to the mono pump 20 together with the nonmetallic catalyst while being crushed by the crushing pump 10. When the mixture of the biomass crushed by the crushing pump 10 and the non-metallic catalyst is transferred to the MONO pump 20, it is mixed with water supplied from the water tank 11 to increase the gasification efficiency of the biomass with supercritical water. It is prepared to a predetermined moisture content (preferably 70 to 95 wt%) that can be increased.

  A mixed liquid containing a nonmetallic catalyst, biomass, and water prepared to a predetermined moisture content is transferred to the pretreatment device 40 through the first heat exchanger 30 by the MONO pump 20. The biomass supplied to the pretreatment device 40 is hydrothermally treated under conditions of a predetermined pressure and a predetermined temperature in the presence of a nonmetallic catalyst supplied together with the biomass.

  The conditions for the hydrothermal treatment are not particularly limited as long as the temperature is in the range of 100 to 250 ° C. and the pressure is in the range of 0.1 to 4 MPa. From the viewpoint of the efficiency of the treatment of decomposing into low molecules, it is preferably the saturation temperature of water under a pressure within these ranges, and from the viewpoint of energy saving, a temperature of 179.8 ° C. and a pressure of 1.0 MPa It is particularly preferred that Here, the hydrothermal treatment is performed at a temperature within the range of 100 ° C. to 250 ° C. The biomass decomposition reaction rate is low below 100 ° C., and if it exceeds 250 ° C., generation of tar and char is concerned. This is because that. In addition, the hydrothermal treatment is performed at a pressure within the range of 0.1 to 4 MPa because the decomposition reaction rate of biomass is low below 0.1 MPa, and the decomposition reaction rate is given even when a pressure higher than 4 MPa is applied. This is because it was thought that there was not much influence.

  Thus, biomass can be efficiently decomposed from a polymer to a low molecule by hydrothermal treatment of the biomass in the presence of a nonmetallic catalyst.

  The biomass slurry body containing the nonmetallic catalyst obtained as described above provides heat to the mixed solution supplied from the MONO pump 20 to the pretreatment device 40 by the first heat exchanger 30, and the slurry supply device. 50. The biomass slurry body containing the nonmetallic catalyst supplied to the slurry supply device 50 is transferred to the fluidized bed reactor 60 through the second heat exchanger 31 by the slurry supply device 50.

  The biomass slurry transferred to the fluidized bed reactor 60 is introduced from the inlet 210 of the fluidized bed reactor 60 and has a predetermined pressure and a predetermined temperature in the presence of the nonmetallic catalyst transferred with the biomass. Hydrothermally treated under conditions. The conditions for the hydrothermal treatment are not particularly limited as long as the temperature is 374 ° C. or higher and the pressure is 22.1 MPa or higher, but the generation of tar and char is suppressed and the reaction efficiency is increased. It is preferable to carry out under the temperature (600 degreeC) and pressure (within the range of 25-35 MPa) which can be performed, and it is especially preferable to carry out at 600 degreeC and 25 MPa from a viewpoint of the burden of equipment, deterioration prevention, and energy saving. In addition, when controlling the ratio of the components in the fuel gas converted from biomass, the temperature and pressure conditions are adjusted, and the fluid density and reaction time (retention of biomass in the fluidized bed reactor 60) are adjusted. This is possible by controlling the time).

  Thus, by reacting the biomass slurry body with supercritical water, it becomes possible to generate combustion gas from the biomass slurry body. In addition, by reducing the biomass from a polymer in advance, the contact efficiency with water or a non-metallic catalyst can be increased, and furthermore, the gasification reaction time of the biomass can be shortened. Fuel gas such as hydrogen gas, methane, ethane, and ethylene can be generated more efficiently from the slurry body.

  The product gas and ash produced by hydrothermally treating the biomass slurry in the fluidized bed reactor 60 and the nonmetallic catalyst and water (supercritical water) are discharged from the outlet 220 of the fluidized bed reactor 60. Discharged. These exhausts provide heat to the biomass slurry body containing the nonmetallic catalyst, which is supplied from the slurry supply device 50 to the fluidized bed reactor 60 in the second heat exchanger 31, and is supplied with a cooler 70 and a decompressor. It is cooled and depressurized by 71 and supplied to the gas-liquid separator 80. The exhaust gas supplied to the gas-liquid separator 80 is separated into a product gas (gas component) containing fuel gas and a mixed solution (liquid component) containing ash, a non-metallic catalyst, and water, and the product gas Is stored in the gas tank 81, and the mixed solution is separated into ash, non-metallic catalyst, and water by the solid-liquid separator 82.

  In addition, as a nonmetallic catalyst used in this Embodiment, activated carbon, a zeolite, etc. can be mentioned, for example. Thus, by using a non-metallic catalyst instead of an alkali metal-based catalyst, it is possible to prevent deterioration due to corrosion of equipment or piping caused by the alkali metal-based catalyst, and long-term use of the system 100 can be realized. Become. In addition, a processing step for neutralizing the alkali metal catalyst is not required, and the efficiency of workability can be improved. As the non-metallic catalyst, it is preferable to use a powder having an average particle size of 200 μm or less, and more preferably porous. By using such a nonmetallic catalyst, it is possible to increase the surface area and increase the reaction efficiency, and to prevent clogging of equipment, piping and the like in the system 100 due to the nonmetallic catalyst. In addition, it is preferable that the nonmetallic catalyst used in this Embodiment is in the range of 1: 5-20: 1 by mass ratio (nonmetallic catalyst: biomass) with dry biomass, The gasification efficiency is particularly preferably in the range of 1: 2 to 20: 1.

  Further, when the biomass to be treated in the present embodiment is wastewater sludge or manure containing foreign matters such as sand, before and after the hot water treatment of the biomass in the pretreatment device 40, a known separation technique (for example, It is also possible to remove foreign substances such as sand contained in the biomass by a separation method using a strainer or a separation method using a sediment layer. As a result, troubles caused by foreign matters such as sand can be prevented.

  Hereinafter, the present invention will be specifically described by way of examples. These examples are for explaining the present invention, and do not limit the scope of the present invention.

[Example 1]
30 parts by mass or 60 parts by mass of activated carbon having a particle size of 100 μm is added to 100 parts by mass of a potato paste having a water content of 90%, and the mixture is stirred and mixed. The reaction with supercritical water was carried out for 1 hour. As a control experiment, a gasification reaction with supercritical water was similarly performed without adding activated carbon. As a result, when no activated carbon is added, the gasification rate is 20% or less in terms of carbon dioxide, whereas when 30 parts by mass of activated carbon is added, the gasification rate increases to 30%. It became clear. It was also found that when the amount of activated carbon was increased to 60 parts by mass, the gasification rate further increased to 60%.

[Example 2]
Next, 80 parts by mass of water, 20 parts by mass of cellulose powder, and 20 parts by mass of activated carbon having an average particle size of 100 μm were stirred and mixed to prepare a slurry. Thereafter, 40 ml of the slurry was poured into a 167 ml autoclave equipped with a stirrer, and the temperature was raised to 400 ° C. while stirring at a pressure of 25 MPa and held for 1 hour to perform a gasification reaction with supercritical water. After the reaction, the reaction mixture was cooled to room temperature, and the product gas was recovered to determine the carbon gasification rate. As a control experiment, the same treatment was performed without adding activated carbon. As a result, it was found that the carbon gasification rate was 10% when no activated carbon was added, whereas the carbon gasification rate increased to 30% when activated carbon was added.

  From the above, it has been clarified that the gasification efficiency can be increased by the addition of the nonmetallic catalyst and the gasification efficiency can be further increased by the addition of the increased amount. Further, it was shown that even when a biomass slurry containing activated carbon is supplied to the fluidized bed reactor, the activated carbon contained in the slurry acts as a catalyst, and the biomass can be efficiently gasified.

[Example 3]
As shown in FIG. 2, a dispersion plate (net) is provided below a fluidized bed reactor 60 (φ12.3 mm × 2400 mm) provided with an inlet 210 and an outlet 220, and alumina balls having an average particle diameter of 1 mm are fluidized. Installed as a medium. In this fluidized bed reactor 60, instead of biomass (ash) or a non-metallic catalyst, a mixed liquid in which alumina particles (average particle size is 180 to 250 μm, or average particle size is 250 to 300 μm) is mixed with water, Alumina particles were ejected and introduced from the inlet 210 at a flow rate (0.19 m / s to 0.60 m / s) at which the alumina ball as the fluid medium did not eject, and the alumina particles discharged from the outlet 220 were collected.

  As a result, when alumina particles having an average particle size of 180 to 250 μm are introduced into the fluidized bed reactor 60, 97.5% alumina particles can be recovered, and alumina particles having an average particle size of 250 to 300 μm are recovered. When introduced into the fluidized bed reactor 60, it was found that 98.9% alumina particles could be recovered. From this, a biomass slurry containing a nonmetallic catalyst (average particle size of 300 μm or less) is supplied to the fluidized bed reactor 60 as described above at a predetermined flow rate (for example, the maximum at which the fluidized medium does not jump out from the discharge port). The generated product gas and ash as well as the nonmetallic catalyst and water (supercritical water) are obtained by performing a hydrothermal reaction at a predetermined temperature and a predetermined pressure while being introduced from the inlet 210 at a flow rate). It was shown that it can be discharged from the outlet 220.

It is a figure which shows schematic structure of the biomass gasification system by the supercritical water demonstrated as one Embodiment of this invention. It is a figure which shows schematic structure of the fluidized bed reactor demonstrated as one Embodiment of this invention. It is a figure which shows schematic structure of the solid-liquid separator demonstrated as one Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Crushing pump 11 Water tank 20 Mono pump 30 1st heat exchanger 31 2nd heat exchanger 40 Pretreatment apparatus 50 Slurry supply apparatus 60 Fluidized bed reactor 70 Cooler 71 Depressurizer 80 Gas-liquid separator 81 Gas tank 82 Solid-liquid separator 90 Burner 100 Biomass gasification system using supercritical water

Claims (18)

A pretreatment apparatus for hydrothermally treating biomass in the presence of a nonmetallic catalyst under conditions of a temperature in the range of 100 to 250 ° C and a pressure in the range of 0.1 to 4 MPa;
Fluid obtained by hydrothermally treating the biomass slurry containing the nonmetallic catalyst obtained by hydrothermal treatment in the pretreatment apparatus under conditions of a temperature of 374 ° C. or higher and a pressure of 22.1 MPa or higher A bed reactor,
With
The fluidized bed reactor is
An inlet for introducing the slurry body into the fluidized bed reactor from below;
A product gas and ash produced by hydrothermal treatment in the fluidized bed reactor, and a discharge port for discharging the non-metallic catalyst and water from above to the fluidized bed reactor;
A fluidized medium that forms a fluidized bed in the fluidized bed reactor by introducing the slurry body;
A dispersion part for dispersing the slurry introduced from the introduction port below the fluidized bed;
With
The fluid medium is configured in a shape that is not discharged at the introduction speed of the slurry body ,
Wherein the dispersing section, biomass gasification system according to supercritical water characterized that you formed by stacking alumina balls.   The product gas, the ash content, the nonmetallic catalyst, and the water discharged from the fluidized bed reactor are mixed into the product gas and a mixed solution containing the ash content, the nonmetallic catalyst, and water. The system according to claim 1, further comprising a gas-liquid separator for separating.   The system according to claim 2, further comprising means for recovering the nonmetallic catalyst in the mixed solution.   The system according to claim 1, further comprising a heating device that heats the fluidized bed reactor using a part of the product gas.   The system according to any one of claims 1 to 4, further comprising a crusher that crushes in advance the biomass to be hydrothermally treated by the pretreatment device. Means for supplying the slurry body hydrothermally treated in the fluidized bed reactor to the fluidized bed reactor;
Heat that preheats the slurry body supplied to the fluidized bed reactor using heat of the exhaust gas containing the product gas, the ash, the nonmetallic catalyst, and water discharged from the discharge port. An exchange,
The system according to claim 1, further comprising: Means for supplying the biomass to be subjected to hydrothermal treatment in the pretreatment device to the pretreatment device;
A heat exchanger that preheats the biomass supplied to the pretreatment device using the heat of the slurry body;
The system according to claim 1, further comprising: Means for supplying the biomass to be subjected to hydrothermal treatment in the pretreatment device to the pretreatment device;
A heat exchanger that preheats the biomass supplied to the pretreatment device using the heat of the exhaust gas containing the product gas, the ash, the nonmetallic catalyst, and water discharged from the discharge port. When,
The system according to claim 1, further comprising:   The system according to claim 1, wherein the hot water treatment in the pretreatment apparatus is performed under conditions of a predetermined pressure and a saturation temperature of water at the pressure.   The system according to claim 1, wherein the fluid medium is an alumina ball. A system according to any one of claims 1 to 10, wherein the non-metallic catalyst, characterized in that activated carbon. The system according to claim 11 , wherein the activated carbon is a powder having an average particle size of 200 μm or less. A system according to any one of claims 1 to 12, wherein the hydrothermal treatment in a fluidized bed reactor, and carrying out under the conditions of 600 ° C. temperature, and pressure of 25 MPa. A supercritical water biomass gasifier that gasifies biomass with supercritical water,
An inlet for introducing the biomass slurry containing the nonmetallic catalyst into the apparatus from below;
Inside the apparatus, the slurry body is hydrothermally treated under conditions of a temperature of 374 ° C. or higher and a pressure of 22.1 MPa or higher, and the generated gas and ash, and the nonmetallic catalyst and water are moved upward. A discharge port for discharging from the device to the outside,
A fluidized medium that forms a fluidized bed in the apparatus by introducing the slurry body;
A dispersion part for dispersing the slurry introduced from the introduction port below the fluidized bed;
With
The fluid medium is configured in a shape that is not discharged at the introduction speed of the slurry body ,
The dispersing portion, supercritical water biomass gasification apparatus characterized that you formed by stacking alumina balls. The apparatus of claim 14 , wherein the fluid medium is an alumina ball. The apparatus according to claim 14 or 15 , wherein the nonmetallic catalyst is activated carbon. The system according to claim 16 , wherein the activated carbon is a powder having an average particle size of 200 μm or less. The apparatus according to any one of claims 14 to 17 , wherein the hydrothermal treatment is performed under conditions of a temperature of 600 ° C and a pressure of 25MPa.

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