JP2007269946A - Biomass gasification apparatus using supercritical water and system including the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a gasification technology using supercritical water effectively forming fuel gas such as methane and hydrogen from biomass. <P>SOLUTION: The system comprises a pretreatment apparatus treating the biomass with hot water under a predetermined temperature and pressure in the presence of a non-metallic catalyst, a reactor subjecting the biomass slurry with the non-metallic catalyst obtained by the hot water treatment to a hydrothermal treatment under a predetermined temperature and pressure, a slurry feeder continuously feeding the slurry with a constant concentration from the pretreatment apparatus to the reactor, a first pressure accumulator installed between the pretreatment apparatus and the slurry feeder to accumulate pressure of the slurry to be received by the slurry feeder, and a second pressure accumulator installed between the slurry feeder and the reactor to accumulate pressure of the slurry fed from the slurry feeder. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a system for gasifying biomass with supercritical water.

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 reactor for hydrothermally treating under a pressure of 22.1 MPa, a slurry supply device for receiving the slurry body from the pretreatment device and supplying the slurry body to the reactor, and the pretreatment A first pressure accumulator which is disposed between the apparatus and the slurry supply apparatus and accumulates the slurry body received by the slurry supply apparatus; A second pressure accumulator disposed between the reactor and accumulating the slurry body supplied from the slurry supply device, the slurry supply device including an injection port for injecting water, and the injected Two cylinders comprising a discharge port for discharging water, a receiving port for receiving the slurry body from the pretreatment device, and a supply port for supplying the received slurry body to the reactor; and the cylinder in each cylinder Pistons arranged so as to partition water and the slurry body, shafts provided with the pistons at both ends, a stirrer for stirring the slurry body in each cylinder, and the first cylinder from the pretreatment device And receiving the slurry body and supplying the slurry body received from the pretreatment device to the second cylinder to the reactor. And supplying the slurry body received in the first cylinder to the reactor, and receiving the slurry body from the pretreatment device in the second cylinder. And a water injection device for alternately switching the second step of injecting the water into the first cylinder.

  The shaft may further include contact preventing means for preventing contact between the piston and the stirrer. Moreover, the said water injection apparatus is good also as inject | pouring a liquid with a fixed flow volume with respect to each cylinder.

  The reactor includes an inlet for introducing the slurry body into the reactor from below, a product gas and ash generated by hydrothermal treatment in the reactor, and the nonmetallic catalyst and water upward. From the outlet, the fluid medium that forms a fluidized bed in the reactor by introduction of the slurry body, and the slurry body introduced from the inlet is dispersed below the fluidized bed. And the dispersion medium is configured to have a shape that is not discharged at the introduction speed of the slurry body.

  The system according to the present invention includes the product gas, the ash, the nonmetallic catalyst, and the water discharged from the reactor, the product gas, the ash, the nonmetallic catalyst, and water. It is good also as providing the gas-liquid separation apparatus isolate | separated into the liquid mixture containing. The system according to the present invention may further include means for recovering the nonmetallic catalyst in the mixed solution.

  Furthermore, the system according to the present invention may further include a heating device that heats the reactor using a part of the product gas generated by hydrothermal treatment in the reactor. The system according to the present invention may further include a crusher that crushes the biomass to be hydrothermally treated by the pretreatment device in advance.

  The system according to the present invention includes a heat exchanger that preheats the slurry body supplied from the slurry supply device to the reactor using heat of the generated gas generated by hydrothermal treatment in the reactor. Further, it may be provided. Further, the system according to the present invention includes means for supplying the biomass to be subjected to hydrothermal treatment in the pretreatment device to the pretreatment device, and heat of the slurry body received from the pretreatment device to the slurry supply device. It is good also as providing further using the heat exchanger which preheats the said biomass supplied to the said pre-processing apparatus. Furthermore, the system according to the present invention utilizes means for supplying the biomass to be subjected to hydrothermal treatment in the pretreatment device to the pretreatment device, and heat of the product gas produced by hydrothermal treatment in the reactor. And it is good also as providing further the heat exchanger which pre-heats the said biomass supplied to the said pre-processing apparatus.

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

  The fluid medium is, for example, an alumina ball. The dispersion part is, for example, a layer formed by stacking alumina balls. 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, reactor 60, cooler 70, decompressor 71, gas-liquid separator 80, gas tank 81, solid-liquid separator 82, burner 90, and the like.

  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 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. The reactor 60 is not particularly limited as long as it is a device capable of hydrothermally treating a biomass slurry containing a nonmetallic catalyst under the above-mentioned conditions, but continuous operation as shown in FIG. 2 is possible. It is preferable to use a simple device.

  FIG. 2 is a diagram showing a schematic configuration of a reactor 60 described as an embodiment of the present invention. A reactor 60 as shown in FIG. 2 includes an inlet 210 for introducing a slurry body of biomass containing a nonmetallic catalyst into the apparatus 60 from below, and the slurry body in the apparatus 60 at a temperature of 374 ° C. or higher. And the generated gas and the ash content including the fuel gas generated by hydrothermal treatment under the pressure of 22.1 MPa or more, and the nonmetallic catalyst and water (supercritical water) are discharged out of the apparatus 60 from above. A discharge port 220, a fluid medium 230 that forms a fluidized bed in the apparatus 60 by introducing the slurry body, and a dispersion unit 240 that disperses the slurry body introduced from the inlet 210 below the fluidized bed are provided.

  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 a 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, or a mesh at 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.

  By using the reactor 60 as described above, the slurry body introduced from the introduction port 210 is gasified with supercritical water using a nonmetallic catalyst contained therein, and the produced gas ( (Including fuel gas) and ash, and a non-metallic catalyst and water (supercritical water) such as water (supercritical water) can be discharged from the discharge port 220 with a lighter and smaller diameter material. In addition, such a reactor 60 can suppress accumulation of ash, nonmetallic catalyst, and the like in the reactor 60 with the above-described configuration, and biomass including the nonmetallic catalyst. It becomes possible to perform a process of continuously gasifying the slurry body with supercritical water.

  The slurry supply device 50 is a device that receives a biomass slurry containing a nonmetallic catalyst obtained by performing the hydrothermal treatment in the pretreatment device 40 from the pretreatment device 40 and supplies the biomass slurry to the reactor 60. FIG. 3 shows a schematic configuration diagram of a slurry supply apparatus 50 described as an embodiment of the present invention. As shown in FIG. 3, the slurry supply apparatus 50 includes two cylinders 310 and 320, a shaft 330, two pistons 331 and 332, two agitators 340 and 350, a water injection device 360, valves 361, 362, 363, and 364. , 373, 374, 375, 376, three-way valves 371, 372, pressure accumulators 380, 381 and the like.

  The water injection device 360 is a device that injects water into each of the cylinders 310 and 320 by alternately switching the cylinder 310 and the cylinder 320. The water injection device 360 is, for example, a pump, a high pressure pump, a back pressure pump, or the like.

  The cylinders 310 and 320 are provided with injection / discharge ports for injecting water from the water injection device 360 and discharging the injected water. Further, the cylinders 310 and 320 are provided with receiving / supplying ports that receive the slurry body from the pretreatment device 40 and supply the received slurry body to the reactor 60.

  Pistons 331 and 332 are disposed in the cylinders 310 and 320 so as to partition water injected from the water injection device 360 and a slurry body received from the pretreatment device 40.

  Pistons 331 and 332 are provided at both ends of the shaft 330. The pistons 331 and 332 are moved in the cylinders 310 and 320 when water is injected into the cylinders 310 and 320 from the water injection device 360, and the slurry bodies in the cylinders 310 and 320 are pressed to slurry in the reactor 60. Supply the body. Further, as one piston 331, 332 moves, the other piston 332, 331 moves coaxially with one piston 331, 332, receives the slurry body from the pretreatment device 40, and in the cylinders 320, 310 Drain the water.

  In order to prevent the water in the cylinders 310 and 320 from mixing with the slurry body, a piston ring may be provided on the pistons 331 and 332 to improve the airtightness between the pistons 331 and 332 and the cylinders 310 and 320. .

  In the present embodiment, a stopper 333 is provided at the center of the shaft 330. The stopper 333 is a device that prevents contact between the pistons 331 and 332 and the stirrers 340 and 350. When the stopper 333 contacts the cylinders 310 and 320, the pistons 331 and 332 cannot move toward the stirrers 340 and 350. It has become a mechanism.

  The valves 361, 362, 363, and 364 are devices that switch the water to flow from the water injection device 360 to the cylinders 310 and 320 and switch the water in the cylinders 310 and 320 to discharge. The valves 361, 362, 363, 364 are, for example, electromagnetic valves.

  In the present embodiment, the valves 361, 362, 363, and 364 are switched so that water flows into the cylinders 310 and 320 by the water injection of the water injection device 360. Further, the valves 361, 362, 363, and 364 are switched so that water is discharged by drainage from the cylinders 310 and 320. Such switching can be performed electrically with water injection from the water injection device 360 or drainage from the cylinders 310 and 320, for example. Specifically, when it is detected that the stopper 333 provided on the shaft 330 has contacted one of the cylinders 310 and 320, the water injection device 360 injects water from the cylinders 310 and 320 into the other cylinders 320 and 310. Switching, the valves 363, 361 are switched so that water flows from the water injection device 360 to the cylinders 320, 310, the valves 364, 362 are switched so that the water injected from the water injection device 360 into the cylinders 320, 310 is not discharged, The valves 362 and 364 may be switched so that water is discharged from the cylinders 310 and 320, and the valves 361 and 363 may be controlled so that the water discharged from the cylinders 310 and 320 does not flow to the water injection device 360.

  In the present embodiment, the slurry supply device 50 is provided with valves 361, 362, 363, 364, but instead of these valves 361, 362, 363, 364, two three-way valves are provided, It may be switched so that the water flows into the cylinders 310 and 320 by the water injection of the water injection device 360, or the water may be discharged by the drainage from the cylinders 320 and 310. Such switching can be mechanically performed by, for example, a valve that prevents backflow, but can also be electrically performed in accordance with water injection from the water injection device 360 or drainage from the cylinders 310 and 320. Specifically, when it is detected that the stopper 333 provided on the shaft 330 has contacted one of the cylinders 310 and 320, the water injection device 360 injects water from the cylinders 310 and 320 into the other cylinders 320 and 310. Switching may be performed so that one of the three-way valves is switched so that water flows from the water injection device 360 to the cylinders 320 and 310, and the other three-way valve is switched so that water is discharged from the cylinders 310 and 320.

  The three-way valves 371 and 372 are switched so that the slurry body flows from the pretreatment device 40 to the cylinders 310 and 320 or the slurry body flows from the cylinders 310 and 320 to the reactor 60 by the reciprocating motion of the pistons 331 and 332. It is a device that switches.

  In the present embodiment, the three-way valves 371 and 372 are switched so that the slurry body flows from the pretreatment device 40 to the cylinders 310 and 320 when the slurry body is received from the pretreatment device 40. The three-way valves 371 and 372 are switched so that the slurry body flows from the cylinders 310 and 320 to the reactor 60 when the slurry body is supplied from the cylinders 310 and 320. Such switching can be mechanically performed by, for example, a valve for preventing backflow, but is electrically performed in accordance with the slurry body supply from the cylinders 310 and 320 and the slurry body supply from the pretreatment device 40. You can also Specifically, when it is detected that the stopper 333 provided on the shaft 330 is in contact with one of the cylinders 310 and 320, the three-way valves 371 and 372 cause the slurry body to flow from the pretreatment device 40 to the cylinders 310 and 320. The three-way valves 372 and 371 may be controlled so that the slurry flows from the other cylinders 320 and 310 to the reactor 60. The detection of the contact between the stopper 333 and the cylinders 310 and 320 is performed, for example, by providing a switch in a part of the region where the stopper 333 and the cylinder 310 and 320 are in contact and pressing the switch. Can do.

  The valves 373 and 374 are used when the slurry body is supplied to the reactor 60 by switching from one cylinder 310 or 320 to the other cylinder 320 or 310, that is, the cylinders 310 and 320 into which water is injected by the water injection device 360. When switching from one cylinder 310, 320 to the other cylinder 320, 310, the apparatus temporarily interrupts the flow (supply) of the slurry body from the cylinder 310, 320 to the reactor 60. The valves 375 and 376 are used to switch the cylinders 310 and 320 into which the water injection device 360 injects water from the one cylinder 310 and 320 to the other cylinder 320 and 310 from the pretreatment device 40 to the cylinders 310 and 320. This is a device for temporarily blocking the flow (acceptance) of the slurry body. The valves 373, 374, 375, and 376 are, for example, electromagnetic valves.

  In addition, the above interruption | blocking can be electrically performed with the water injection from the water injection apparatus 360 and the waste_water | drain from the cylinders 310 and 320, for example. Specifically, when it is detected that the stopper 333 provided on the shaft 330 is in contact with one of the cylinders 310 and 320, the valves 373 and 374 flow (supply) the slurry body from the cylinders 310 and 320 to the reactor 60. The valves 375 and 376 block the flow (acceptance) of the slurry body from the pretreatment device 40 to the cylinders 310 and 320, and the water injection device 360 supplies water from the cylinders 310 and 320 to the other cylinders 320 and 310. Of the valves 373 and 374, one of the valves 374 and 373 is opened so that the slurry body flows from the cylinders 320 and 310 to the reactor 60 through the three-way valves 372 and 371, and the valves 375 and 376 are opened. One of the valves 375 and 376 removes the slurry from the pretreatment device 40 to the cylinder 310, It may be performed a control that opens to flow 20.

  The agitators 340 and 350 are devices for agitating the slurry body received in the cylinders 310 and 320 from the pretreatment device 40 via the three-way valves 371 and 372. As described above, by stirring the slurry body with the stirrers 340 and 350 in the cylinders 310 and 320, it is possible to prevent precipitation of solid substances such as non-metallic catalyst and biomass particles contained in the slurry body. It becomes like this.

  In the present embodiment, between the slurry supply device 50 and the reactor 60, the pressure accumulator 380 that accumulates a slurry body supplied from the slurry supply device 50, and between the pretreatment device 40 and the slurry supply device 50. And a pressure accumulator 381 for accumulating a slurry body received by the slurry supply device 50. By providing these, the pressure in the pipe connecting the slurry supply apparatus 50 and the reactor 60 and the pressure in the pipe connecting the pretreatment apparatus 40 and the slurry supply apparatus 50 can be kept constant, and pulsation And the occurrence of water hammer (water hammer) can be prevented.

  Note that the switching of the cylinders 310 and 320 into which water is injected by the water injection device 360 described above may be performed electrically at the timing when the stopper 333 provided on the shaft 330 contacts the cylinders 310 and 320. It is good also as detecting and detecting that the pressure in 310,320 increased. The water injected by the water injection device 360 into the cylinders 310 and 320 is preferably water having the same temperature as the temperature of the slurry body received in the cylinders 310 and 320. Thereby, the temperature drop of the slurry body received by the cylinders 310 and 320 can be suppressed. In addition, it is preferable to perform water injection to the cylinders 310 and 320 by the water injection device 360 at a constant flow rate so that the slurry body can be supplied to the reactor 60 at a constant flow rate.

  In the above description, the stopper 333 is provided on the shaft 330 of the slurry supply device 50 to prevent contact between the pistons 331 and 332 and the stirrers 340 and 350. 330 may be adjusted to prevent contact between the pistons 331 and 332 and the stirrers 340 and 350, or an amount of water that does not contact the pistons 331 and 332 and the stirrers 340 and 350 may be injected. It is good also as preventing the contact with piston 331,332 and stirrer 340,350 so that the apparatus 360 may inject | pour into the cylinder 310,320. Moreover, it is good also as providing a stopper in cylinder 310,320 so that piston 331,332 and agitator 340,350 may not contact.

  Furthermore, in the above description, the cylinders 310 and 320 are provided with injection / discharge ports for injecting water from the water injection device 360 and discharging the injected water, but the injection ports for injecting water from the water injection device 360 The cylinders 310 and 320 may be provided with discharge ports for discharging the injected water.

  In the above description, the cylinders 310 and 320 are provided with receiving / supply ports for receiving the slurry body from the pretreatment device 40 and supplying the received slurry body to the reactor 60. The cylinders 310 and 320 may be provided with a receiving port for receiving the slurry and a supply port for supplying the received slurry body to the reactor 60, respectively.

  The cooler 70 is a device that cools the discharge discharged from the reactor 60. The exhaust discharged from the reactor 60 contains explosive fuel gas (for example, hydrogen, methane, ethane, ethylene, etc.), water vapor (supercritical water), etc. The cooler 70 is provided in the system 100 of the present invention for the purpose of converting water vapor into water. In the present embodiment, the cooler 70 is described as an example of a device for cooling the discharge discharged from the reactor 60. However, the device that can cool the discharge discharged from the reactor 60. Any device may be used as long as it is.

  The decompressor 71 is a device that decompresses the pressure of the product gas or the like in the exhaust discharged from the 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 is an apparatus that separates the effluent discharged from the reactor 60 into a gas component (product gas) and a liquid component (water or a mixed solution containing water, ash, non-metallic catalyst, etc.). It is. 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 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 an apparatus for heating the reactor 60. However, any apparatus can be used as long as the apparatus can heat the reactor 60. Good.

  When the liquid component separated by the gas-liquid separator 80 contains ash other than water, nonmetallic catalyst, or the like, the solid-liquid separator 82 has solid content such as ash or nonmetallic catalyst and water. Is a device for separating The solid-liquid separator 82 may be, for example, an existing solid-liquid separator, or an apparatus that separates ash, non-metallic catalyst, and water in the mixed liquid. In FIG. 4, the schematic block diagram of the solid-liquid separator 82 which isolate | separates the ash 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. 4, the solid-liquid separator 82 includes a mixed liquid injection unit 410, a water tank 420, a circulation pump 430, a supply pipe 440, an ash receiving unit 450, valves 460, 461, and 470.

  The mixed liquid injection unit 410 is a pipe for injecting a mixed liquid containing ash, activated carbon, and water from the gas-liquid separator 80. The water tank 420 is a container in which water for slowly allowing ash and activated carbon in the mixed liquid injected from the mixed liquid injection section 410 to settle is put. The water tank 420 has a discharge port 421 for allowing ash in the liquid mixture injected from the liquid mixture injection unit 410 to settle and discharge the water from the water tank 420, an activated carbon receiving part 422 423 for receiving activated carbon in the liquid mixture, and an ash floating in the water tank 420. And a drain outlet 424 for discharging suspended matter such as activated carbon and water together with water.

  The ash receiving unit 450 is a container that receives the ash that has settled from the discharge port 421. The circulation pump 430 is a pump that circulates the water in the water tank 420. The supply pipe 440 is a pipe that introduces water circulated by the circulation pump 430 into the water tank 420 through the discharge port 421. The water circulated by the circulation pump 430 is supplied from the discharge port 421 to the water tank 420 at a flow rate that is faster than the sedimentation rate of the activated carbon and slower than the sedimentation rate of the ash. Thereby, the ash in the mixed liquid injected from the mixed liquid injection unit 410 settles in the ash receiving unit 450 through the discharge port 421, but the activated carbon in the mixed liquid injected from the mixed liquid injection unit 410 is It moves to the activated carbon receiving part 422,423 without passing through the discharge port 421.

  In the present embodiment, the activated carbon receivers 422 and 423 are provided with ridges 425 and 426 made of finer mesh than the activated carbon particles so that the activated carbon collected in the receivers 422 and 423 can be collected. The ash receiving unit 450 is provided with a ridge 451 made of a mesh finer than ash particles so that the ash collected in the receiving unit 450 can be collected.

  The valves 460 and 461 are valves that discharge water from the water tank 420. After separating the ash and activated carbon in the mixed solution injected from the gas-liquid separator 80, the activated carbon accumulated in the tanks 425 and 426 is recovered by draining the water in the water tank 420 through the valves 460 and 461. Can do. Further, the valve 470 is a valve for draining water from the ash receiving unit 450. After separating the ash and activated carbon in the mixed solution injected from the gas-liquid separator 80, the ash collected in the tub 451 can be recovered by draining the water of the ash receiving portion 450 by the valve 470. .

  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 in the pretreatment device 40. This device preheats biomass.

  The second heat exchanger 31 uses the heat of the effluent discharged from the reactor 60 including the product gas generated by hydrothermal treatment in the reactor 60 and the reactor 60 to the reactor 60. Is a device for preheating a biomass slurry containing a nonmetallic catalyst.

  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 body using the heat of the exhaust discharged from the reactor 60. The system 100 of the present invention may be provided with a heat exchanger that preheats biomass and the like supplied from the MONO pump 20 to the pretreatment device 40 using the heat of the discharge discharged from the vessel 60.

  As described above, by providing the system 100 according to the present invention with the slurry supply device 50 as described above, the above-described slurry body that is easily separated into a solid component and a liquid component is continuously supplied to the reactor 60 at a constant concentration. Therefore, it is possible to continuously supply a slurry body containing a nonmetallic catalyst or biomass at a concentration with the highest gasification efficiency of supercritical water to the reactor 60 to generate fuel gas more efficiently from biomass. Is possible.

  Moreover, since the biomass can be decomposed from a polymer to a low molecule by providing the system 100 according to the present invention with a pretreatment device 40 for hydrothermally treating biomass in advance, the biomass and water to be treated in the reactor 60 In addition, the efficiency of contact with non-metallic catalysts can be increased, the generation of char and tar can be prevented, and fuel gas can be efficiently generated from biomass.

  Further, since the biomass slurry body having excellent fluidity can be formed by hydrothermally treating the biomass in the pretreatment device 40, clogging of equipment, piping, etc. due to the biomass in the supply to the reactor 60 is prevented. It becomes possible to do.

  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 reactor 60 by the system 100 according to the present invention, thereby reducing catalyst consumption. It becomes possible to do.

  Furthermore, by providing the reactor 100 as shown in FIG. 2 in the system 100 according to the present invention, ash (residue) obtained by gasifying biomass with supercritical water is not accumulated in the reactor 60. In addition, gasification treatment of biomass with supercritical water can be performed continuously, and fuel gas can be generated more efficiently from biomass.

  In addition, by providing the system 100 according to the present invention with the cooler 70, the decompressor 71, the gas-liquid separator 80, etc., it is possible to safely recover the generated gas including the fuel gas from the exhaust discharged from the reactor 60 Will be able to.

  Furthermore, since the biomass can be crushed beforehand by providing the system 100 according to the present invention with a device (crushing pump 10) for crushing biomass, the efficiency of biomass slurrying and gasification can be increased. .

  Moreover, since electric power and exhaust heat can be obtained by generating power 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 slurry body of biomass containing the nonmetallic catalyst that has been hydrothermally treated in the pretreatment device 40 is directly supplied to the reactor 60 using the slurry supply device 50. The slurry body may be preheated by a heating device (for example, a heater or the like) before being supplied to the 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. In the present embodiment, a method using the system 100 including the reactor 60 capable of continuous operation as shown in FIG. 2 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 accepted. The slurry body of biomass containing the nonmetallic catalyst received by the slurry supply device 50 is supplied to the reactor 60 through the second heat exchanger 31 by the slurry supply device 50.

  The biomass slurry supplied to the reactor 60 is introduced into the reactor 60 and hydrothermally treated under the conditions of a predetermined pressure and a predetermined temperature in the presence of the nonmetallic catalyst supplied with the biomass. 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. When it is desired to control the ratio of components in the fuel gas converted from biomass, the temperature and pressure conditions are adjusted, and the fluid density and reaction time (the residence time of biomass in the reactor 60) are adjusted. It becomes possible by controlling the above.

  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 generated by hydrothermally treating the biomass slurry in the reactor 60 is discharged from the reactor 60. The discharged material supplies heat to the biomass slurry body including the nonmetallic catalyst supplied from the slurry supply device 50 to the reactor 60 in the second heat exchanger 31, and is cooled by the cooler 70 and the decompressor 71. The pressure is reduced 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 liquid (liquid component) containing water or water, ash, non-metallic catalyst, etc. The generated gas is stored in the gas tank 81. If the liquid component separated by the gas-liquid separator 80 contains ash other than water, non-metallic catalyst, or the like, and the non-metallic catalyst is to be recovered, the mixed liquid is ashed by the solid-liquid separator 82. Separated into non-metallic catalyst and water.

  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 mixture is press-fitted into a fluidized bed reactor with a high-pressure pump, under conditions of 500 ° C. and 25 MPa. 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 reactor demonstrated as one Embodiment of this invention. It is a figure which shows schematic structure of the slurry supply apparatus 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 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 (17)

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;
Reaction of 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 And
A slurry supply device for receiving the slurry body from the pretreatment device and supplying the slurry body to the reactor;
A first pressure accumulator arranged between the pretreatment device and the slurry supply device and accumulating the slurry body received in the slurry supply device;
A second pressure accumulator that is disposed between the slurry supply device and the reactor and accumulates the slurry body supplied from the slurry supply device;
With
The slurry supply apparatus includes:
An inlet for injecting water, an outlet for discharging the injected water, an inlet for receiving the slurry body from the pretreatment device, and a supply port for supplying the received slurry body to the reactor. Two cylinders with
A piston arranged to partition the water and the slurry body in each cylinder;
A shaft with each piston at both ends;
A stirrer for stirring the slurry body in each cylinder;
The second cylinder is adapted to receive the slurry body from the pretreatment device into the first cylinder and to supply the slurry body received from the pretreatment device to the second cylinder to the reactor. Supplying the slurry body received in the first cylinder to the reactor, and receiving the slurry body from the pretreatment device in the second cylinder; A water injection device for alternately switching the second step of injecting the water into the first cylinder;
A biomass gasification system using supercritical water, comprising:   The system according to claim 1, wherein the shaft further comprises contact prevention means for preventing contact between the piston and the agitator.   The system according to claim 1, wherein the water injection device injects water at a constant flow rate for each cylinder. The reactor is
An inlet for introducing the slurry body into the reactor from below;
A product gas and ash produced by hydrothermal treatment in the reactor, and a discharge port for discharging the nonmetallic catalyst and water from the top to the outside of the reactor;
A fluidized medium that forms a fluidized bed in the reactor by introducing the slurry body;
A dispersion part for dispersing the slurry introduced from the introduction port below the fluidized bed;
With
The system according to any one of claims 1 to 3, wherein the fluid medium has a shape that is not discharged at an introduction speed of the slurry body.   The product gas, the ash, the nonmetallic catalyst, and the water discharged from the reactor are separated into the product gas and a mixed solution containing the ash, the nonmetallic catalyst, and water. The system according to claim 4, further comprising a gas-liquid separator.   The system according to claim 5, further comprising means for recovering the nonmetallic catalyst in the mixed solution.   The system according to claim 4, wherein the fluid medium is an alumina ball.   The system according to claim 4, wherein the dispersion portion is formed by stacking alumina balls.   The system according to claim 1, further comprising a heating device that heats the reactor by using a part of the product gas generated by hydrothermal treatment in the reactor.   The system according to any one of claims 1 to 9, further comprising a crusher that crushes the biomass to be hydrothermally treated with the pretreatment device in advance.   The apparatus further comprises a heat exchanger that preheats the slurry body supplied from the slurry supply device to the reactor using heat of the generated gas generated by hydrothermal treatment in the reactor. The system according to claim 1. 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 received by the slurry supply device from the pretreatment device;
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 product gas generated by hydrothermal treatment in the reactor;
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 nonmetallic catalyst is activated carbon.   The system according to claim 15, wherein the activated carbon is a powder having an average particle size of 200 μm or less. The system according to claim 1, wherein the hydrothermal treatment in the reactor is performed under conditions of a temperature of 600 ° C. and a pressure of 25 MPa.

Images