Biomass Gasifier

Abstract

To provide a biomass gasification apparatus that can dissolve the jamming of woody biomass while maintaining a reaction temperature.SOLUTION: A biomass gasification apparatus 100 comprises: a gasification reaction furnace 10; an upper feed part 20 that supplies woody biomass and an inert gas from above through a makeup hole 25 to the gasification reaction furnace 10; a lower feed part 30 that supplies a mixture gas containing the inert gas from below; a state detection part that detects a jamming state where woody biomass is jammed in the makeup hole 25; and a flow rate control part that controls the feed parts 20, 30 to adjust a supply amount of the inert gas based on the detection result. When the jamming state is detected, the flow rate control part increases the supply amount of the inert gas from the upper feed part 20 to be greater than a predetermined first supply amount, and decreases the supply amount of the inert gas from the lower feed part 30 to be less than a predetermined second supply amount, such that the sum of the supply amounts of the inert gas is maintained at a constant value.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a biomass gasification apparatus for gasifying biomass. [Background technology]

[0002] Conventionally, there has been known an apparatus for continuously supplying and gasifying biomass (see, for example, Patent Document 1). In the apparatus described in Patent Document 1, an observation window is provided at an input section where biomass is input into a gasification reactor, and a clogged state of the input section is detected by an optical sensor through the observation window. When a clogged state of the input section clogged with biomass is detected, high-pressure nitrogen gas is sprayed toward the input section to remove the biomass clogged in the input section. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2009-235141 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the device described in Patent Document 1, if the biomass becomes clogged, nitrogen gas is injected into the reactor through the inlet, which temporarily reduces the temperature inside the reactor and lowers the reaction temperature, making it difficult to carry out a stable gasification reaction. [Means for solving the problem]

[0005] A biomass gasification apparatus according to one aspect of the present invention includes a gasification reactor, an upper supply unit that supplies woody biomass and an inert gas to the gasification reactor from above through an inlet, a lower supply unit that supplies a mixed gas containing the inert gas to the gasification reactor from below, a state detection unit that detects a clogging state in which the inlet is clogged with woody biomass, and a flow rate control unit that controls the upper supply unit and the lower supply unit to adjust the amount of inert gas supplied by the upper supply unit and the amount of inert gas supplied by the lower supply unit based on the detection result by the state detection unit. When the state detection unit detects the clogging state, the flow rate control unit increases the amount of inert gas supplied by the upper supply unit above a predetermined first supply rate and decreases the amount of inert gas supplied by the lower supply unit below a predetermined second supply rate so that the sum of the amount of inert gas supplied by the upper supply unit and the amount of inert gas supplied by the lower supply unit is maintained at a constant value. Effect of the Invention

[0006] According to the present invention, clogging of wood biomass can be eliminated while maintaining the reaction temperature. [Brief description of the drawings]

[0007] [Figure 1] FIG. 2 is a diagram illustrating an example of a configuration of the periphery of a gasification reactor of the biomass gasification apparatus according to the embodiment of the present invention. [Diagram 2] An enlarged view of the area around the injection hole in Figure 1. [Diagram 3] FIG. 2 is a block diagram illustrating an example of a control configuration of the biomass gasification apparatus according to the embodiment of the present invention. [Figure 4] FIG. 2 is a diagram for explaining the flow state of the fluid medium in FIG. 1; [Diagram 5] 4 is a flowchart showing an example of a flow rate control process executed by the controller of FIG. 3. [Figure 6] FIG. 13 is an enlarged view of the vicinity of an input hole of a biomass gasification apparatus according to a modified example. [Figure 7] FIG. 7 is a block diagram illustrating an example of a control configuration for the biomass gasification apparatus of FIG. 6. [Figure 8] 8 is a flowchart showing an example of a flow rate control process executed by the controller of FIG. 7. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] Hereinafter, an embodiment of the present invention will be described with reference to Fig. 1 to Fig. 8. A biomass gasification apparatus according to an embodiment of the present invention produces synthesis gas containing carbon monoxide, methane, etc. by pyrolyzing woody biomass. The synthesis gas can be used as fuel gas for a gas engine for power generation, for example.

[0009] The average temperature of the Earth is kept warm enough for living things by greenhouse gases in the atmosphere. Specifically, greenhouse gases absorb some of the heat radiated from the Earth's surface, which is warmed by sunlight, into space, and then re-radiate it back to the Earth's surface, thereby keeping the atmosphere warm. If the concentration of greenhouse gases in the atmosphere increases, the average temperature of the Earth will rise (global warming).

[0010] Of all greenhouse gases, carbon dioxide contributes greatly to global warming, and its concentration in the atmosphere is determined by the balance between carbon fixed on or in the ground as biomass or fossil fuels, and carbon present in the atmosphere as carbon dioxide. For example, when carbon dioxide in the atmosphere is absorbed through photosynthesis during the growth of plants (biomass), the concentration of carbon dioxide in the atmosphere decreases, and when carbon dioxide is released into the atmosphere through the consumption (combustion) of fossil fuels, the concentration of carbon dioxide in the atmosphere increases. To curb global warming, it is necessary to replace fossil fuels with renewable fuels derived from biomass and reduce carbon emissions.

[0011] In gasification of woody biomass, woody biomass chips that have been crushed in advance are fed into a high-temperature gasification reactor and carbonized. In order to proceed with the desired chemical reaction in the gasification reactor and stably produce synthesis gas of the desired composition, it is necessary to maintain the temperature (reaction temperature) inside the gasification reactor at an appropriate temperature. However, since woody biomass thermally expands under high-temperature conditions, it may clog the input section. Therefore, in this embodiment, the biomass gasification device is configured as follows so that clogging of woody biomass can be eliminated while maintaining the reaction temperature.

[0012] Fig. 1 is a diagram showing an example of the configuration of the periphery of a gasification reactor 10 of a biomass gasification apparatus (hereinafter, apparatus) 100 according to an embodiment of the present invention. As shown in Fig. 1, the apparatus 100 includes the gasification reactor 10, an upper supply unit 20 that supplies woody biomass and nitrogen gas, which is an inert gas, to the gasification reactor 10 from above, and a lower supply unit 30 that supplies a mixed gas of water vapor, hydrogen gas, and nitrogen gas to the gasification reactor 10 from below.

[0013] The gasification reactor 10 includes an outer pipe 11 and an inner pipe 12 extending about a vertical axis CL1, and a generally cylindrical electric furnace 13 provided in close contact with the outer circumferential surface of the outer pipe 11. The upper end of the inner pipe 12 is located above the upper end of the outer pipe 11, and the lower end of the inner pipe 12 is located above the lower end of the outer pipe 11. The upper end of the outer pipe 11 is closed by a ring-shaped upper cover 14 that connects the inner circumferential surface of the outer pipe 11 and the outer circumferential surface of the inner pipe 12. The upper end 12a of the inner pipe 12 is located above the upper cover 14. The lower end of the outer pipe 11 is closed by a lower cover 15, and an opening 15a is provided in the center of the lower cover 15. A supply pipe 16 connected to a lower supply unit 30 is inserted into the opening 15a.

[0014] The supply pipe 16 is provided with a plurality of holes 16a in a range facing the inner peripheral surface of the outer pipe 11. The upper end surface of the supply pipe 16 is closed by a disk-shaped plate 16b having a plurality of holes 16c radially provided therein. A cylindrical space SP1 between the inner peripheral surface of the outer pipe 11 and the outer peripheral surface of the supply pipe 16 is filled with alumina beads having a relatively large diameter, with a gap remaining below the plate 16b. A space SP2 in the outer pipe 11 from the upper surface of the plate 16b to a predetermined height is filled with alumina beads having a relatively small diameter. The mixed gas flowing into the space SP1 through the holes 16a of the supply pipe 16 flows through the gaps between the alumina beads filled in the space SP1, flows into the space SP2 through the holes 16c of the plate 16b, and flows through the gaps between the alumina beads filled in the space SP2. By filling the spaces SP1 and SP2 with alumina beads, it becomes easier to maintain the temperatures of the spaces SP1 and SP2, and the flow of the mixed gas passing through the space SP2 can be rectified.

[0015] A space SP3 in the outer tube 11 from the top surface of the layer of alumina beads filled in the space SP2 to the bottom surface of the top cover 14 is filled with a fluidized medium such as silica sand to a predetermined height. The lower end 12b of the inner tube 12 is located in the layer of fluidized medium (filled layer) filled in the space SP3. Woody biomass chips are supplied from above to the space SP3. The fluidized medium and chips in the space SP3 are fluidized by being blown up by the mixed gas supplied from below, and behave like a liquid. The fluidized layer of fluidized medium (fluidized bed) becomes the reaction field for the gasification reaction. In the fluidized bed with a uniform temperature distribution, the mixed gas and the woody biomass chips come into sufficient and uniform contact with each other, resulting in a uniform temperature distribution, and thus the reaction rate of the gasification reaction can be increased.

[0016] The electric furnace 13 is provided so as to surround the outer tube 11 from its lower end to a predetermined height h1. The predetermined height h1 is set in consideration of the height h2 to which the fluidized medium in the space SP3 is blown upward. As a result, the inside of the gasification reactor 10 becomes a water vapor atmosphere due to the mixed gas supplied from below, and the fluidized bed in the space SP3 surrounded by the electric furnace 13 is maintained at a predetermined reaction temperature. When woody biomass chips are supplied to this fluidized bed from above through the input holes 25, a gasification reaction (pyrolysis reaction) of the biomass proceeds in the fluidized bed, and synthesis gas is produced.

[0017] The outer tube 11 is provided with an outlet 11a above the electric furnace 13. The synthesis gas generated in the fluidized bed is discharged from the gasification reactor 10 through the space SP3 above the fluidized bed and the outlet 11a. The synthesis gas discharged from the gasification reactor 10 is used after moisture, tar components, etc. are removed through a gas-liquid separator, a condenser, etc. (not shown).

[0018] The upper supply section 20 includes a hopper 21 for storing chips, a supply pipe 22 extending about a horizontal axis CL2 and connecting a discharge port 21a of the hopper 21 to the inner pipe 12 of the gasification reactor 10, and a screw 23 disposed in the supply pipe 22. One end 23a of the screw 23 is connected to a motor 24, and the other end 23b of the screw 23 is located in the inner pipe 12 of the gasification reactor 10. The screw 23 is driven by the motor 24 to rotate about the axis CL2, and transports chips that have dropped from the hopper 21 into the inner pipe 12 via the discharge port 21a. The space in the supply pipe 22 facing the other end 23b of the screw 23 is hereinafter referred to as an input hole 25.

[0019] The upper supply unit 20 further includes a nitrogen supply unit 26 that is connected to the upper end 12a of the inner pipe 12 and supplies nitrogen gas from above into the gasification reactor 10 via the inner pipe 12. The nitrogen supply unit 26 is configured as a high-pressure tank filled with nitrogen gas, and a piping connecting the nitrogen supply unit 26 and the upper end 12a of the inner pipe 12 is provided with an adjustment valve 26a that adjusts the flow rate Un1 of the nitrogen gas supplied from above into the gasification reactor 10.

[0020] FIG. 2 is an enlarged view of the vicinity of the input hole 25. As shown in FIG. 2, a nozzle portion 25a is provided on the inlet side of the input hole 25, a diffuser portion 25b is provided on the outlet side of the input hole 25, and the input hole 25 is formed as a venturi portion in which the inner diameter of the inner tube 12 is narrowed. The flow rate of the nitrogen gas supplied from above by the nitrogen supply portion 26 increases as it passes through the nozzle portion 25a, and the chips supplied to the input hole 25 from the side by the screw 23 can be sprayed downward through the diffuser portion 25b. In addition, since the flow rate of the nitrogen gas increases, the input hole 25 becomes negative pressure, and the chips transported by the screw 23 can be sucked in. As a result, woody biomass chips, which are prone to fluffing, can be supplied to the gasification reactor 10 from above through the input hole 25 together with the nitrogen gas.

[0021] The lower supply unit 30 includes a mixer heater 31 connected to the lower end of the supply pipe 16, a water supply unit 32 that supplies water to the mixer heater 31, a hydrogen supply unit 33 that supplies hydrogen gas to the mixer heater 31, and a nitrogen supply unit 26 that supplies nitrogen gas to the mixer heater 31. The water supply unit 32 is configured as a water supply pump that pumps water from a water source (not shown) and supplies it to the mixer heater 31, and a piping connecting the water supply unit 32 and the mixer heater 31 is provided with an adjustment valve 32a that adjusts the flow rate Us of water. The hydrogen supply unit 33 is configured as a high-pressure tank filled with hydrogen gas, and a piping connecting the hydrogen supply unit 33 and the mixer heater 31 is provided with an adjustment valve 33a that adjusts the flow rate Uh of hydrogen gas. A piping connecting the nitrogen supply unit 26 and the mixer heater 31 is provided with an adjustment valve 26b that adjusts the flow rate Un2 of nitrogen gas supplied from below into the gasification reactor 10.

[0022] In the mixer heater 31, water supplied from a water supply unit 32 is heated and vaporized to generate water vapor, which is mixed with hydrogen gas supplied from a hydrogen supply unit 33 and nitrogen gas supplied from a nitrogen supply unit 26 to generate a high-temperature mixed gas. The high-temperature mixed gas generated in the mixer heater 31 is supplied into the gasification reactor 10 from below via a supply pipe 16.

[0023] FIG. 3 is a block diagram schematically showing an example of the control configuration of the apparatus 100. As shown in FIG. 3, the apparatus 100 further includes a controller 40 that controls the regulating valves 26a, 26b, 32a, and 33a. Also, as shown in FIGS. 2 and 3, a pressure sensor 41 that detects the pressure P1 on the inlet side (upstream side of the nozzle portion 25a) of the charging hole 25, a pressure sensor 42 that detects the pressure P2 on the outlet side (downstream side of the diffuser portion 25b) of the charging hole 25, a pressure sensor 43 that detects the pressure P3 on the lower side (inlet side), for example, in the supply pipe 16, of the packed bed of the fluid medium, and a pressure sensor 43 that detects the pressure P4 on the upper side (outlet side), for example, at the upper part of the packed bed, of the packed bed are provided.

[0024] As shown in FIG. 2, in a normal state where the charging hole 25 is not clogged with chips, the pressure P1 on the inlet side of the charging hole 25 and the pressure P2 on the outlet side become equal (P1 = P2). On the other hand, in a clogged state where the charging hole 25 is clogged with chips, due to the occurrence of a pressure loss, the pressure P1 on the inlet side of the charging hole 25 becomes lower than the pressure P2 on the outlet side (P1 < P2). The pressure sensors 41 and 42 may also be referred to as a state detection unit that detects the clogged state of the charging hole 25.

[0025] The controller 40 is configured to include a computer having a CPU, a RAM, a ROM, an I / O interface, and other peripheral circuits, and the CPU functions as a flow rate control unit that controls the upper supply unit 20 (regulating valve 26a) and the lower supply unit 30 (regulating valves 26b, 32a, 33a). Based on the pressures P1 and P2 detected by the pressure sensors 41 and 42, it is determined whether the charging hole 25 is in a normal state or a clogged state. When the controller 40 determines that the charging hole 25 is in a normal state, the regulating valves 26a, 26b, 32a, and 33a are controlled so that the flow rate Un (Un = Un1 + Un2) of the nitrogen gas supplied into the gasification reactor 10, the flow rate Us of water (steam), and the flow rate Uh of hydrogen gas become the specified flow rates Un0, Us0, and Uh0.

[0026] The specified flow rate Us0 of water (steam) is determined so that the weight ratio S / B of steam (S) to biomass (B) is a predetermined value (e.g., about 0.5) according to the supply amount of woody biomass per unit time (e.g., about 100 [g / h]). The specified flow rate Un0 of nitrogen gas is determined so that the ratio of steam to nitrogen gas is a predetermined value (e.g., about 40:60) according to the specified flow rate Us0 of water (steam). Similarly, the specified flow rate Uh0 of hydrogen gas is determined so that the ratio of steam to hydrogen gas is a predetermined value according to the specified flow rate Us0 of water (steam). This allows a desired chemical reaction to proceed in the gasification reactor, and a synthesis gas of a desired composition can be produced.

[0027] The specified flow rate Un10 of nitrogen gas supplied from above is determined as the value (αUn0) obtained by multiplying the specified flow rate Un0 of nitrogen gas by a predetermined value α (0<α<1). The specified flow rate Un20 of nitrogen gas supplied from below is determined as the value ((1-α)Un0) obtained by multiplying the specified flow rate Un0 of nitrogen gas by a predetermined value (1-α).

[0028] When the controller 40 determines that the input hole 25 is clogged, it controls the regulating valves 26a and 26b to increase the flow rate Un1 of the nitrogen gas supplied from above and to decrease the flow rate Un2 of the nitrogen gas supplied from below so that the flow rate Un of the nitrogen gas supplied into the gasification reactor 10 is maintained at the specified flow rate Un0. That is, the flow rate Un1 of the nitrogen gas supplied from above is increased to a value (Un10+ΔUn) obtained by adding a predetermined flow rate ΔUn to the specified flow rate Un10, and the flow rate Un2 of the nitrogen gas supplied from below is decreased to a value (Un20-ΔUn) obtained by subtracting the predetermined flow rate ΔUn from the specified flow rate Un20.

[0029] By increasing the flow rate Un1 of the nitrogen gas supplied from above, the flow rate of the nitrogen gas in the input hole 25 is increased, and the chips are blown downward, thereby eliminating clogging of the input hole 25. In this case, since the reaction conditions such as the weight ratio S / B of the water vapor and the biomass are maintained, the reaction rate of the desired chemical reaction is not decreased, and the yield of the synthesis gas of the desired composition is not decreased. In addition, by decreasing the flow rate Un2 of the nitrogen gas supplied from below in response to an increase in the flow rate Un1 of the nitrogen gas supplied from above, the total amount of nitrogen gas supplied into the gasification reactor 10 is maintained at a constant amount. In this case, since the heat capacity and reaction temperature in the gasification reactor 10 are maintained, the reaction rate of the desired chemical reaction is not decreased, and the yield of the synthesis gas of the desired composition is not decreased.

[0030] The predetermined flow rate ΔUn to be added to or subtracted from the specified flow rates Un10 and Un20 can be gradually increased until the state detection unit does not detect the clogging state, provided that the flow velocity Uc of the mixed gas is within a flow velocity range that can maintain a fluidized bed in the gasification reactor 10.

[0031] Fig. 4 is a diagram for explaining the flow state of the bed material. In Fig. 2, the horizontal axis indicates the flow velocity Uc of the mixed gas supplied from below by the lower supply unit 30 into the gasification reactor 10, and the vertical axis indicates the pressure difference ΔP between the pressure P3 on the lower side (inlet side) of the packed bed of the bed material and the pressure P4 on the upper side (outlet side). The flow rate [m 3 / sec] can be calculated based on the flow rate of nitrogen gas supplied from below, Un2, the flow rate of water (steam), Us, the flow rate of hydrogen gas, Uh, and the temperature of the mixed gas. The flow velocity of the mixed gas, Uc [m / sec], is the average flow velocity when it flows into the packed bed of the bed material, and the flow rate of the mixed gas [m 3 / sec] by the cross-sectional area of ​​the outer tube 11 (space SP3).

[0032] As shown in FIG. 1, the mixed gas supplied from below into the gasification reactor 10 is rectified in the space SP2 and flows into the packed bed in the space SP3. As shown in FIG. 4, when the flow velocity Uc when flowing into the packed bed is low, the mixed gas flows through the gaps between the bed materials, the bed materials remain stationary, and the bed materials do not fluidize (fixed bed). When the flow velocity Uc increases, the pressure in the gaps between the bed materials through which the mixed gas flows gradually decreases, and the pressure drop (pressure loss) in the packed bed, that is, the pressure difference ΔP between the inlet side and the outlet side of the packed bed, increases. When such a pressure drop (pressure difference ΔP) exceeds the weight of the packed bed (bed materials), the bed materials start to fluidize (fluidized bed). When fluidization starts, the pressure difference ΔP becomes constant. The pressure drop (pressure difference ΔP) when fluidization starts is called the fluidization pressure drop Plim, and the flow velocity Uc when fluidization starts is called the minimum fluidization velocity Umf.

[0033] By maintaining the flow rate Uc of the mixed gas at about 3 to 5 times the minimum fluidization velocity Umf, it is possible to maintain a healthy fluidized bed. The specified flow rate Un20 of the nitrogen gas supplied from below is determined so that the flow rate Uc of the mixed gas is, for example, about 5 times the minimum fluidization velocity Umf. By setting the specified flow rate Un20 of the nitrogen gas supplied from below near the upper limit of the range in which a healthy fluidized bed can be maintained, it is possible to ensure a sufficient margin when reducing the flow rate Un2 of the nitrogen gas supplied from below depending on the clogging state of the input hole 25.

[0034] The controller 40 calculates the pressure difference ΔP in the packed bed of the fluidized medium based on the pressures P3 and P4 detected by the pressure sensors 43 and 44, and judges whether the calculated pressure difference ΔP is equal to or greater than the fluidization pressure drop Plim. If it is judged that the pressure difference ΔP is less than the fluidization pressure drop Plim and the fluidized bed cannot be maintained, the controller 40 controls the regulating valves 26a and 26b so that the flow rate Un1 of the nitrogen gas supplied from above is returned to the specified flow rate Un10, and the flow rate Un2 of the nitrogen gas supplied from below is returned to the specified flow rate Un20. This controls the lower supply unit 30 (regulating valve 26b) so that the flow rate Uc of the mixed gas is always equal to or greater than the minimum fluidization speed Umf, and the fluidized bed can be maintained. Note that when the flow rate Uc of the mixed gas is adjusted, the pressure difference ΔP changes mainly due to the change in the pressure P3 on the inlet side of the packed bed. The pressure P4 on the outlet side of the packed bed is usually maintained at the pressure inside the gasification reactor 10, which is equivalent to the atmospheric pressure.

[0035] When the controller 40 determines that the fluidized bed cannot be maintained based on the pressures P3 and P4 and returns the nitrogen gas to the specified flow rates Un10 and Un20, if it determines that the inlet 25 is clogged, it controls the regulating valve 32a to reduce the water (steam) flow rate Us. In other words, if the clogging of the inlet 25 cannot be cleared, the flow rate Us of the steam is reduced in accordance with the reduction in the amount of biomass supplied, thereby maintaining reaction conditions such as the weight ratio S / B of the steam to biomass. As a result, although the yield of the synthesis gas decreases, the operation of the apparatus 100 can be continued while maintaining the desired reaction rate of the chemical reaction and the yield of the synthesis gas with the desired composition.

[0036] FIG. 5 is a flowchart showing an example of a flow rate control process executed by the controller 40. The process shown in this flowchart is repeatedly executed at a predetermined cycle. As shown in FIG. 5, first, in step S1, it is determined whether or not the pressure P1 detected by the pressure sensors 41, 42 is lower than the pressure P2. If the result in step S1 is negative, it is determined that the input hole 25 is in a normal state, and the process ends. If the result in step S1 is positive, it is determined that the input hole 25 is in a clogged state, and the process proceeds to step S2. In step S2, the flow rate Un1 of the nitrogen gas supplied from above is increased by a predetermined flow rate ΔUn, and the flow rate Un2 of the nitrogen gas supplied from below is decreased by the predetermined flow rate ΔUn, so as to control the regulating valves 26a, 26b.

[0037] Next, in step S3, the pressure difference ΔP in the packed bed of the fluidized medium is calculated based on the pressures P3 and P4 detected by the pressure sensors 43 and 44, and it is determined whether the calculated pressure difference ΔP is equal to or greater than the fluidization pressure drop Plim. If the result in step S3 is positive, it is determined that the fluidized bed is being maintained, and the process ends. If the result in step S3 is negative, it is determined that the fluidized bed is not being maintained, and the process proceeds to step S4, where the regulating valves 26a and 26b are controlled to return the flow rate Un1 of the nitrogen gas supplied from above and the flow rate Un2 of the nitrogen gas supplied from below to the specified flow rates Un10 and Un20.

[0038] Next, in step S5, it is determined whether or not pressure P1 detected by pressure sensors 41, 42 is lower than pressure P2. If the result in step S5 is negative, it is determined that input hole 25 is in a normal state, and the process ends. If the result in step S5 is positive, it is determined that input hole 25 remains clogged, and the process proceeds to step S6, where adjustment valve 32a is controlled to reduce the flow rate Us of water (steam), and the process ends.

[0039] 6 is an enlarged view of the vicinity of the input hole 25 of a biomass gasification apparatus (hereinafter, apparatus) 100A according to a modified example. In the apparatus 100A, an opening / closing unit 27 is provided below the input hole 25 (diffuser section 25b). Also, instead of the pressure sensors 41 and 42, a position sensor 45 is provided on the inner wall surface of the inner pipe 12 between the input hole 25 (diffuser section 25b) and the opening / closing unit 27. The position sensor 45 is provided a predetermined height h3 above the upper surface of the opening / closing unit 27. The predetermined height h3 is set in consideration of the height of chips accumulated on the opening / closing unit 27 every predetermined time (for example, 1 min) according to the supply amount of woody biomass per unit time (for example, about 100 g / h).

[0040] Position sensor 45 is configured as, for example, a contact sensor, and when the chips piled up on opening / closing section 27 reach a predetermined height h3, it comes into contact with the chips to detect that the chips have piled up to the predetermined height h3 and transmits a signal to opening / closing section 27. Opening / closing section 27 is normally closed and opens / closes (opens and then closes) in response to a signal from position sensor 45, causing chips piled up on the upper surface to fall downward at predetermined intervals. In a normal state where chips are not clogged in insertion hole 25, position sensor 45 detects the accumulation of chips at predetermined intervals, but in a clogged state where insertion hole 25 is clogged with chips, the accumulation of chips is not detected at predetermined intervals. Position sensor 45 is also called a state detection section that detects the clogged state of insertion hole 25.

[0041] Fig. 7 is a block diagram showing an example of the control configuration of the device 100A. As shown in Fig. 7, a position sensor 45 is connected to a controller 40A of the device 100A instead of the pressure sensors 41 and 42. The controller 40A monitors a signal transmitted from the position sensor 45 to the opening / closing unit 27, and determines whether the input hole 25 is in a normal state or in a clogged state.

[0042] 8 is a flowchart showing an example of a flow rate control process executed by the controller 40A. The process shown in this flowchart is repeatedly executed, for example, at predetermined time intervals. As shown in FIG. 8, first, in step S7, it is determined whether or not the accumulation of chips is detected at predetermined time intervals by the position sensor 45. If the result in step S7 is positive, it is determined that the input hole 25 is in a normal state, and the process ends. If the result in step S7 is negative, it is determined that the input hole 25 is in a clogged state, and the process proceeds to step S2. The processes in steps S2 to S4 are the same as those in FIG. 5.

[0043] In step S4, when the flow rate Un1 of the nitrogen gas supplied from above and the flow rate Un2 of the nitrogen gas supplied from below are returned to the specified flow rates Un10 and Un20, the process proceeds to step S8, where it is determined whether or not the position sensor 45 detects chip accumulation at predetermined time intervals. If the result in step S8 is positive, it is determined that the input hole 25 is in a normal state, and the process ends. If the result in step S8 is negative, it is determined that the clogged state of the input hole 25 continues, the process proceeds to step S6, and the regulating valve 32a is controlled to reduce the flow rate Us of water (water vapor), and the process ends.

[0044] According to this embodiment, the following advantageous effects can be obtained. (1) The apparatus 100 includes a gasification reactor 10, an upper supply unit 20 that supplies wood biomass and nitrogen gas to the gasification reactor 10 from above through an inlet 25, a lower supply unit 30 that supplies a mixed gas containing nitrogen gas to the gasification reactor 10 from below, a condition detection unit (pressure sensors 41, 42, position sensor 45) that detects a clogging state in which the inlet 25 is clogged with wood biomass, and a controller 40 that controls the upper supply unit 20 (adjusting valve 26a) and the lower supply unit 30 (adjusting valves 26b, 32a, 33a) so as to adjust the supply flow rate Un1 of nitrogen gas by the upper supply unit 20 and the supply flow rate Un2 of nitrogen gas by the lower supply unit 30 based on the detection result by the condition detection unit (Figures 1, 3, 6, 7).

[0045] When a clogging state is detected by the state detection unit, the controller 40 increases the nitrogen gas supply flow rate Un1 by the upper supply unit 20 above a predetermined specified flow rate Un10 and decreases the nitrogen gas supply flow rate Un2 by the lower supply unit 30 below a predetermined specified flow rate Un20 so that the sum (Un1+Un2) of the nitrogen gas supply flow rate Un1 by the upper supply unit 20 and the nitrogen gas supply flow rate Un2 by the lower supply unit 30 (i.e., the flow rate Un of nitrogen gas supplied into the gasification reactor 10) is maintained at the specified flow rate Un0 (steps S1 and S2 of Figure 5, steps S6 and S2 of Figure 8).

[0046] By increasing the supply flow rate Un1 of nitrogen gas by the upper supply unit 20, the flow rate at the input hole 25 can be increased, and the chips clogged in the input hole 25 can be ejected downward, thereby eliminating the clogging state. By detecting and eliminating the clogging state and keeping the supply amount of woody biomass constant, the balance between the reactive gases such as water vapor contained in the mixed gas in the gasification reactor 10 and the biomass can be maintained, and the reaction rate of the desired chemical reaction and the yield of the synthesis gas with the desired composition can be maintained. In addition, by keeping the total amount of nitrogen gas supplied to the gasification reactor 10 constant, the heat capacity and reaction temperature in the gasification reactor 10 can be maintained, and the reaction rate of the desired chemical reaction and the yield of the synthesis gas with the desired composition can be maintained.

[0047] (2) The apparatus 100 further includes a bed material filled in the gasification reactor 10 (FIG. 1). The controller 40 controls the lower supply unit 30 so that the flow velocity Uc of the mixed gas supplied by the lower supply unit 30 becomes equal to or greater than the minimum fluidization velocity Umf of the bed material in the gasification reactor 10 (FIG. 4). This maintains a fluidized bed that serves as a reaction field for the gasification reaction, and can maintain a high reaction rate for the gasification reaction.

[0048] (3) The apparatus 100 further includes pressure sensors 43, 44 for detecting the lower pressure P3 and the upper pressure P4 of the bed material filled in the gasification reactor 10, respectively (FIG. 1). The controller 40 judges whether the bed material is in a predetermined fluidized state based on the pressure difference ΔP between the lower pressure P3 and the upper pressure P4 of the bed material, and if it is judged that the bed material is not in the predetermined fluidized state, returns the supply flow rate Un1 of the nitrogen gas by the upper supply unit 20 to the specified flow rate Un10, and returns the supply flow rate Un2 of the nitrogen gas by the lower supply unit 30 to the specified flow rate Un20 (steps S3, S4 in FIGS. 5 and 8). This makes it possible to constantly maintain a fluidized bed.

[0049] (4) The mixed gas further contains water vapor. When the controller 40 determines that the predetermined flow state is not present and the state detection unit detects a clogging state, it reduces the supply flow rate Us of water vapor by the lower supply unit 30 (steps S3 to S6 in FIG. 5, and steps S3, S4, S7, and S6 in FIG. 8). In this way, even if the clogging state cannot be eliminated, the fluidized bed is maintained, and reaction conditions such as the weight ratio S / B of water vapor to biomass are maintained, so that the desired reaction rate of the chemical reaction and the yield of synthesis gas with the desired composition can be maintained and the operation of the apparatus 100 can be continued.

[0050] In the above embodiment, an example in which woody biomass chips are used is described, but woody biomass is not limited to chips, and may be pellets or powder (wood powder). In the above embodiment, an example in which nitrogen gas is used as the inert gas is described, but the inert gas is not limited to nitrogen gas, and any gas that does not affect the gasification reaction by the biomass gasifier may be used. In the above embodiment, specific configurations of the upper supply unit and the lower supply unit are described as examples, but the upper supply unit and the lower supply unit are not limited to those exemplified. For example, different inert gas supply sources (high-pressure tanks, etc.) may be used for the upper supply unit and the lower supply unit. In the above embodiment, an example in which woody biomass, steam, and hydrogen are used as reactants is described, but the biomass gasifier may use other reactant gases as long as it supplies woody biomass and inert gas from above and a mixed gas containing inert gas from below. In the above embodiment, an example in which a pressure sensor or a position sensor is used as the state detection unit is described, but the state detection unit may be any type as long as it detects a clogging state of the input hole. For example, an image sensor or a weight sensor may be used to detect the clogging or accumulation state of woody biomass. In the above embodiment, a specific arrangement example of the pressure sensors 43 and 44 is shown and described, but the pressure detection units that detect the pressure below and the pressure above the bed material are not limited to those shown in the figures.

[0051] The above description is merely an example, and the present invention is not limited to the above-mentioned embodiment and modifications, as long as the features of the present invention are not impaired. The above-mentioned embodiment and one or more modifications can be arbitrarily combined, and modifications can be combined with each other. [Explanation of symbols]

[0052] 10 gasification reactor, 11 outer tube, 11a exhaust port, 12 inner tube, 12a upper end, 12b lower end, 13 electric furnace, 14 upper cover, 15 lower cover, 15a opening, 16 supply pipe, 16a hole, 16b plate, 16c hole, 20 upper supply section, 21 hopper, 21a exhaust port, 22 supply pipe, 23 screw, 23a one end, 23b other end, 24 motor, 25 input hole, 25a nozzle section, 25b diffuser section, 26 nitrogen supply section, 26a, 26b regulating valve, 27 opening / closing section, 30 lower supply section, 31 mixing heater, 32 water supply section, 32a regulating valve, 33 hydrogen supply section, 33a regulating valve, 40, 40A controller, 41-44 Pressure sensor, 45 Position sensor, 100,100A Biomass gasification equipment (equipment), CL1, CL2 axis, SP1~SP3 space

Claims

1. A gasification reactor; an upper supply section that supplies wood biomass and an inert gas to the gasification reactor from above through an input hole; A lower supply section that supplies a mixed gas containing an inert gas to the gasification reactor from below; a state detection unit that detects a state in which the input hole is clogged with the woody biomass; a flow rate control unit that controls the upper supply unit and the lower supply unit so as to adjust the amount of inert gas supplied by the upper supply unit and the amount of inert gas supplied by the lower supply unit based on a detection result by the state detection unit, The biomass gasification apparatus is characterized in that, when the state detection unit detects the clogged state, the flow control unit increases the amount of inert gas supplied by the upper supply unit above a predetermined first supply amount and decreases the amount of inert gas supplied by the lower supply unit below a predetermined second supply amount so that the sum of the amount of inert gas supplied by the upper supply unit and the amount of inert gas supplied by the lower supply unit is maintained at a constant value.

2. 2. The biomass gasification apparatus according to claim 1, A bed material is further provided in the gasification reactor, The biomass gasification apparatus is characterized in that the flow rate control unit controls the lower supply unit so that the flow velocity of the mixed gas supplied by the lower supply unit is equal to or greater than the minimum fluidization velocity of the bed material in the gasification reactor.

3. The biomass gasification apparatus according to claim 2, The gasification reactor further includes a pressure detection unit for detecting a pressure below the bed material and a pressure above the bed material, The flow control unit determines whether the fluidized medium is in a predetermined fluidized state based on the pressure difference between the pressure below and the pressure above the fluidized medium, and if it determines that the fluidized medium is not in the predetermined fluidized state, returns the amount of inert gas supplied by the upper supply unit to the first supply amount, and returns the amount of inert gas supplied by the lower supply unit to the second supply amount.

4. The biomass gasification apparatus according to claim 3, The mixed gas further comprises water vapor, The biomass gasification apparatus is characterized in that the flow control unit reduces the amount of steam supplied by the lower supply unit when it determines that the specified flow state is not occurring and the state detection unit detects the clogged state.

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