JP6338080B2 - Biomass gasification system using supercritical water - Google Patents

Description

  The present invention relates to a biomass gasification system using supercritical water capable of preventing clogging by suppressing generation of tar and the like.

  Conventionally, in the technology of gasifying hydrous biomass (shochu residue, egg-collecting chicken droppings, etc.) with supercritical water, the heat of products etc. obtained by gasifying biomass with supercritical water is used to make supercriticality. A biomass gasification system using supercritical water equipped with a double-pipe heat exchanger that heats hydrous biomass or biomass slurry that is gasified with water has been developed (see, for example, Patent Documents 1 and 2). .

JP 2007-271146 A JP 2009-242697 A

However, in the biomass gasification system using supercritical water as described above, a product obtained by gasifying hydrous biomass or a slurry of biomass with supercritical water in a double pipe heat exchanger, etc. When heating the hydrous biomass or biomass slurry gasified with supercritical water using heat, tar or the like may be generated, and clogging may occur in the double pipe.
The present invention has been made in view of the above problems, and in a double-pipe heat exchanger, utilizing the heat of a product obtained by gasifying biomass with supercritical water, it is supercritical. Biomass gasification with supercritical water that suppresses the generation of tar and the like and prevents clogging in double pipes when heating hydrous biomass or biomass slurry that is gasified with water The purpose is to provide a system.

  As a result of earnest research to solve the above problems, the present inventors, as a catalyst, a non-metallic catalyst suspended in hydrous biomass, a gasification reactor for gasifying the biomass with supercritical water, The product gas and ash produced in the gasification reactor, and the nonmetallic catalyst is suspended in water, and the heat of the mixture discharged from the gasification reactor is used to increase the amount in the gasification reactor. Using a supercritical water biomass gasification system comprising a double-tube heat exchanger that preheats a suspension in which a nonmetallic catalyst is suspended in hydrous biomass that is gasified with critical water, The pressure in the system is adjusted to 27 MPa or more, and water at about 30 ° C. is used instead of the suspension in the flow path in the inner pipe of the double pipe in the double pipe heat exchanger, and instead of the mixture. Outer pipe of double pipe with water heated to 600 ° C When heat exchange is performed by supplying the flow path to the inner pipe in opposite directions, compared to the case where heat exchange is performed by adjusting the pressure in the system at 23 MPa, the inner pipe of the double pipe In order to complete the present invention, it is found that the time (residence time) in which the water supplied to is maintained at around 380 ° C. (more specifically, a temperature range of 350 to 400 ° C.), which is the tar generation temperature, is shortened. It came.

That is, the biomass gasification system using supercritical water according to the present invention is a gasification in which the biomass is gasified with supercritical water using a hydrous biomass or a non-metallic catalyst suspended in a slurry body of biomass as a catalyst. A reactor, a product gas and ash produced in the gasification reactor, and a non-metallic catalyst suspended in water and discharged from the gasification reactor at 600 ° C., and the gasification The suspension is preheated by heat-exchanging the hydrous biomass gasified with supercritical water in a reactor or a suspension of the non-metallic catalyst suspended in the biomass slurry. in the biomass gasification system with supercritical water and a double-pipe heat exchanger, that is adjusted to within the range of not less than 27 MPa 60 MPa pressure in the system No.

  In addition, you may perform the gasification process in the said gasification reactor in the biomass gasification system by the said supercritical water at the temperature of 600 degreeC or more.

  According to the present invention, in a double-pipe heat exchanger, hydrous biomass that is gasified with supercritical water using the heat of a product or the like obtained by gasifying the biomass with supercritical water. Alternatively, it is possible to provide a biomass gasification system using supercritical water that can suppress the generation of tar and the like and prevent clogging in the double pipe when the biomass slurry is heated.

In one Embodiment of this invention, it is a figure which shows schematic structure of the biomass gasification system by supercritical water. In one Embodiment of this invention, it is a figure which shows schematic structure of the double pipe in a double pipe type heat exchanger. In one embodiment of the present invention, the pressure of the double pipe heat exchanger is adjusted to 23 MPa, water of about 30 ° C. is placed in the inner pipe of the double pipe, and water of about 600 ° C. is placed between the outer pipe and the inner pipe. It is a figure which shows the result of having measured the temperature of each fluid in each point of a double pipe | tube at the time of supplying water in the reverse direction and making it heat-exchange, respectively. In one embodiment of the present invention, the pressure of the double tube heat exchanger is adjusted to 27.5 MPa, water of about 30 ° C. is placed in the inner tube of the double tube, and about 600 between the outer tube and the inner tube. It is a figure which shows the result of having measured the temperature of each fluid in each point of a double tube | pipe at the time of supplying heat | fever water in a reverse direction, respectively, and making it heat-exchange.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. The objects, features, advantages, and ideas of the present invention will be apparent to those skilled in the art from the description of the present specification, and those skilled in the art can easily reproduce the present invention from the description of the present specification. it can. DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments and drawings of the invention described below show preferred embodiments of the present invention and are shown for illustration or explanation, and are not intended to limit the present invention thereto. Absent. It will be apparent to those skilled in the art that various modifications can be made based on the description of the present specification within the spirit and scope of the present invention disclosed herein.

  FIG. 1 is a diagram showing a schematic configuration of a biomass gasification system using supercritical water (hereinafter simply referred to as “system”), which is described as one embodiment of the present invention. As shown in FIG. 1, the system 100 includes a regulating tank 10, a crusher 20, a supply pump 30, a double tube heat exchanger 40, a gasification reactor 50, a cooler 60, a decompressor 70, and a gas-liquid separator. 80, gas tank 90, etc., supply pump 30 and double pipe heat exchanger 40, double pipe heat exchanger 40 and gasification reactor 50, and gasification reactor 50 and heat exchanger 40 are These are connected by piping, and the internal pressures of the double-tube heat exchanger 40 and the gasification reactor 50 are adjusted to 27 MPa or more.

  The adjustment tank 10 is a tank that mixes hydrous biomass (may be a biomass slurry. The same applies hereinafter), a non-metallic catalyst, water, and the like. The gasification raw material to be sent to the system 100 is mixed with the hydrous biomass and the non-metallic catalyst introduced into the adjustment tank 10 and the water introduced as necessary to obtain hydrous biomass (or biomass solution). It is prepared by suspending a nonmetallic catalyst. In addition, the injection | pouring of water is suitably performed according to the moisture content of biomass. The hydrous biomass is, for example, shochu residue, egg-collected chicken droppings, sludge, and the like. The non-metallic catalyst is, for example, activated carbon or zeolite. As the nonmetallic catalyst, particles having an average particle diameter of 200 μm or less are preferably used, and porous particles having an average particle diameter of 200 μm or less are more preferably used.

  The crusher 20 crushes the biomass in the gasification raw material (suspension) prepared in the adjustment tank 10 and has a uniform size in advance (preferably an average particle diameter of 500 μm or less, more preferably an average particle diameter of 300 μm). The following device).

  The gasification reactor 50 is a device that gasifies the biomass in the suspension with supercritical water using a non-metallic catalyst suspended in the suspension in which the biomass is crushed by the crusher 20 as a catalyst. The gasification of biomass with supercritical water is performed by hydrothermally treating the biomass with supercritical water at a temperature of 600 ° C. or higher, for example, using the non-metallic catalyst. By treating the biomass with supercritical water in this way, the biomass can be decomposed and a fuel gas such as hydrogen gas, methane, ethane, or ethylene can be generated.

  The supply pump 30 is a device that supplies the gasification reactor 50 with a suspension obtained by crushing biomass with the crusher 20. The supply pump 30 is not particularly limited as long as it is a device that can supply a suspension obtained by crushing biomass. For example, a high-pressure pump or a Mono pump can be used.

  The double-pipe heat exchanger 40 includes a gasification reactor 50 in which a product gas and ash generated by gasification with supercritical water and a nonmetallic catalyst are suspended in water and gasified. This is an apparatus for preheating a suspension obtained by crushing biomass that is gasified by supercritical water in the gasification reactor 50 using heat of the discharge (mixture) discharged from the reactor 50. As shown in FIG. 2, the double pipe 41 in the double pipe heat exchanger 40 includes an outer pipe 42 and an inner pipe 43, and one of the mixture and the suspension is the inner pipe 43. The other flows through the flow path between the outer tube 42 and the inner tube 43. In this embodiment and this example, it is set so that the suspension flows in the flow path in the inner pipe 43 and the mixture flows in the flow path between the outer pipe 42 and the inner pipe 43. ing.

The cooler 60 is an apparatus for cooling the exhaust (the mixture of product gas, ash, and nonmetallic catalyst suspended in water) discharged from the gasification reactor 50. The cooler 60 is, for example, a cooler.
The decompressor 70 is a device that reduces the pressure of the exhaust discharged from the gasification reactor 50.

The gas-liquid separator 80 converts the effluent discharged from the gasification reactor 50 into a gas component containing a product gas (fuel gas or the like) and a liquid component in which ash and a nonmetallic catalyst are suspended in water. It is a device to separate.
The gas tank 90 is a container (preferably a pressure-resistant container) that stores a gas component (product gas) separated by the gas-liquid separator 80.

  The heater 51 combusts a part of the generated gas (fuel gas) stored in the gas tank 90 or fuel gas (for example, LPG) to heat the gasification reactor 50, and the suspension obtained by pulverizing the biomass is heated. It is an apparatus for heating to a predetermined temperature. The heater 51 is an existing device that burns and heats fuel gas, such as a burner, for example.

  In the present embodiment, the double tube heat exchanger 40 is gasified with supercritical water using heat of a product obtained by gasifying biomass with supercritical water. When the suspension in which the nonmetallic catalyst is suspended in the hydrous biomass is heated, in the inner tube 43 of the double tube 41, the suspension is around 380 ° C. (more specifically, the tar generation temperature). In this case, the generation of tar or the like is suppressed by shortening the time (residence time) held in a temperature range of 350 to 400 ° C., and thus the inside of the double pipe 41, particularly the outer pipe 42 and the inner pipe 43. In order to prevent clogging due to tar or the like in the flow path between the two, the internal pressure of the double-pipe heat exchanger 40 and the gasification reactor 50 is adjusted to 27 MPa or more. When using typical equipment, the equipment can withstand The pressure can bets, for example, it is preferable to adjust a pressure of less than 35 MPa. In addition, when the double-pipe heat exchanger 40 and the gasification reactor 50 are made of a material that can withstand a pressure greater than 35 MPa and less than or equal to 60 MPa, the pressure may be adjusted with these pressures.

  In the present embodiment, a suspension in which a nonmetallic catalyst is suspended in hydrous biomass (or biomass solution) in the adjustment tank 10 is supplied to the double-pipe heat exchanger 40 by the supply pump 30. However, just before the supply pump 30 supplies, the nonmetallic catalyst is suspended in the hydrous biomass (or biomass solution) crushed by the crusher 20 and supplied to the double-tube heat exchanger 40. May be.

  Further, in the present embodiment, the suspension in which the nonmetallic catalyst is suspended in the hydrous biomass supplied to the double-pipe heat exchanger 40 from the supply pump 30 is set at a temperature at which tar is not generated (for example, 350 A preheater that preheats up to about 0 ° C. may be provided separately. This makes it possible to quickly heat the suspension supplied to the gasification reactor 50.

  Using the above-described system 100 including the double-tube heat exchanger 40 and the gasification reactor 50, the outlet pressure in the flow path between the outer tube 42 and the inner tube 43 of the double tube 41 is set to 23 MPa or Adjust the pressure to 27.5 MPa, supply water at about 30 ° C. to the flow path in the inner pipe 43 of the double pipe 41, and flow between the outer pipe 42 and the inner pipe 43 of the double pipe 41. Heat is exchanged by supplying water heated to about 600 ° C. in the gasification reactor 50 in the direction opposite to the traveling direction of the fluid flowing in the inner pipe 43 with respect to the passage, At each point, the temperature of the fluid in the inner tube 43 and the temperature of the fluid between the outer tube 42 and the inner tube 43 were measured. The water flow rate was 0.76 L / min. As the double pipe 41, the inner diameter of the inner pipe 43 is 8 mm, the thickness of the inner pipe 43 is 3 mm, the inner diameter of the outer pipe 42 is 13 mm, the thickness of the outer pipe 42 is 4 mm, and the length is 100 m, The inner tube 43 and the outer tube 42 were each made of SUS316TPS. Further, the temperature of the fluid at each point was measured by setting the inlet of the flow path in the inner pipe 43 or the outlet of the flow path between the outer pipe 42 and the inner pipe 43 to 0 m. The results are shown in FIGS.

  As shown in FIG. 3, when the pressure at the outlet of the flow path between the outer tube 42 and the inner tube 43 is 23 MPa, the water supplied into the inner tube 43 of the double tube 41 is at the tar generation temperature. The distance and time (time is calculated using a specific gravity of 447.59 of water at 375 ° C. and 23 MPa) held at around 380 ° C. (temperature range of 350 to 400 ° C.) are 54 m and 68.6 seconds, respectively. there were. On the other hand, when the pressure at the outlet of the flow path between the outer tube 42 and the inner tube 43 is 27.5 MPa, the pressure is supplied into the inner tube 43 of the double tube 41 as shown in FIG. The distance and time (the time is calculated by using the specific gravity of water at 375 ° C. and 27.5 MPa) is about 380 ° C. (temperature range of 350 to 400 ° C.) which is the tar generation temperature. , 36 m and 54.8 seconds, respectively. Therefore, when the pressure in the system 100 is adjusted to 23 MPa or more by adjusting the pressure in the system 100, that is, the pressure inside the double tube heat exchanger 40 and the gasification reactor 50 to 27 MPa or more. Compared to the above, the time (residence time) in which the water supplied to the inner pipe 43 of the double pipe 41 is maintained at around 380 ° C. (more specifically, a temperature range of 350 to 400 ° C.), which is the tar generation temperature, is short. It has become clear that the generation of tar and the like can be suppressed, and clogging due to tar and the like can be prevented in the pipe of the double pipe 41, particularly in the flow path between the outer pipe 42 and the inner pipe 43. .

DESCRIPTION OF SYMBOLS 10 Adjustment tank, 20 Crusher, 30 Supply pump, 40 Double pipe type heat exchanger, 41 Double pipe, 42 Outer pipe, 43 Inner pipe, 50 Gasification reactor, 51 Heater, 60 Cooler, 70 Depressurization , 80 gas-liquid separator, 90 gas tank, 100 biomass gasification system using supercritical water

Claims (2)

A gasification reactor for gasifying the biomass with supercritical water using a hydrous biomass or a non-metallic catalyst suspended in a biomass slurry as a catalyst;
Product gas and ash generated in the gasification reactor, and wherein the non-metallic catalyst is suspended in water, a mixture of 600 ° C. discharged from the gasification reactor, super in the gasification reactor Double-tube type that preheats the suspension by heat-exchanging the hydrous biomass gasified with critical water or a suspension in which the non-metallic catalyst is suspended in the biomass slurry. A heat exchanger,
In the biomass gasification system with supercritical water comprising
A biomass gasification system using supercritical water, wherein the pressure in the double-pipe heat exchanger is adjusted within a range of 27 MPa to 60 MPa .   The biomass gasification system using supercritical water according to claim 1, wherein the gasification treatment in the gasification reactor is performed at a temperature of 600 ° C. or more.

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