Gasification method, method for producing semi-carbonized bamboo material, and semi-carbonized bamboo material

Abstract

To provide a gasification method for efficiently generating gas from a biomass fuel material, a method for producing a semi-carbonized bamboo material, and the semi-carbonized bamboo material.SOLUTION: Gas can be efficiently produced from a biomass fuel material produced from a woody material or a herbaceous material by a gasification method comprising: a carbonization step in which the woody material or the herbaceous material is carbonized to produce the biomass fuel material; a semi-carbonization step in which the bamboo material is semi-carbonized to produce the semi-carbonized bamboo material; and a gasification step in which the biomass fuel material and the semi-carbonized bamboo material are introduced as fuel materials into a gasifier for releasing gas and the fuel materials are gasified, wherein the bamboo material is superheated with superheated steam in the semi-carbonization step.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to a gasification method for producing gas from biomass fuel material, a method for producing semi-carbonized bamboo material, and semi-carbonized bamboo material. [Background technology]

[0002] As environmental issues have been receiving increasing attention in recent years, research is underway into gasification methods that can efficiently obtain gas as an energy source from naturally occurring biomass fuel materials, instead of using fossil fuels such as oil and coal as raw materials for power generation.

[0003] For example, Patent Document 1 discloses a so-called updraft type gasification apparatus for gasifying biomass fuel material, in which biomass fuel material is introduced from above a reaction tower and gas generated from the biomass fuel material inside the reaction tower is discharged from above. As biomass fuel materials are used to obtain gas that serves as an energy source, it is desirable to efficiently generate gas obtained from biomass fuel materials. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2008-101215 Summary of the Invention [Problem to be solved by the invention]

[0005] The object of the present invention is to provide a gasification method for efficiently producing gas from biomass fuel material, a method for producing semi-carbonized bamboo material, and semi-carbonized bamboo material. [Means for solving the problem]

[0006] The present inventors have conducted extensive research and found that the above-mentioned problems can be solved by the following configuration. That is, the present invention is characterized by a gasification method that includes a carbonization process in which woody or herbaceous materials are carbonized or semi-carbonized to produce biomass fuel material, a semi-carbonization process in which bamboo material is semi-carbonized to produce semi-carbonized bamboo material, and a gasification process in which the biomass fuel material and the semi-carbonized bamboo material are mixed in a predetermined ratio to produce fuel material, which is then fed into a gasification device that releases gas and the fuel material is gasified, and in the semi-carbonization process, the bamboo material is superheated with superheated steam.

[0007] The wood-based materials are organic resources of biological origin consisting of wood, and include, for example, coniferous trees, broad-leaved trees, deciduous trees, pruned fruit trees, fast-growing trees, and driftwood. The herbaceous materials are organic resources derived from non-tree-forming plants, and include, for example, sorghum, bamboo, coffee grounds, rice husks, weeds, reeds, and grasses.

[0008] According to the present invention, gas can be efficiently produced from biomass fuel material produced from wood-based materials or herbaceous materials. More specifically, in the gasification process for gasifying biomass fuel, the amount of gas generated from semi-carbonized bamboo and biomass fuel can be increased at 700-800°C, where biomass fuel residue is likely to be generated. This reduces the amount of residue generated from semi-carbonized bamboo and biomass fuel compared to when only biomass fuel is gasified.

[0009] As an aspect of the present invention, it is preferable that in the gasification step, the semi-carbonized bamboo material fed into the gasification device is 25 to 50% by volume of the fuel material. This invention increases the amount of gas produced and makes it possible to make the composition of the gas produced a higher calorific value, thereby enabling more efficient gas production from biomass fuel materials.

[0010] In addition, in the semi-carbonization step, it is preferable to semi-carbonize the bamboo material with superheated steam set at 300°C. According to this invention, it is possible to reliably increase the amount of gas produced from semi-carbonized bamboo and biomass fuel and reliably reduce the amount of residue produced from semi-carbonized bamboo and biomass fuel. Therefore, it is possible to reliably and efficiently produce high calorific value gas from biomass fuel made from wood-based materials or herbaceous materials.

[0011] As another embodiment of the present invention, in the semi-carbonization step, the mass of the bamboo material before semi-carbonization may be reduced by 30 to 50%. Furthermore, this invention is characterized in that the semi-carbonized bamboo material accounts for 30 to 50% of the mass of the raw bamboo material.

[0012] This allows the amount of gas produced from semi-carbonized bamboo and biomass fuel to be increased at gasification temperatures of 700 to 800°C, thereby further reducing the residue produced from semi-carbonized bamboo and biomass fuel.

[0013] Furthermore, in the gasification method and the method for producing semi-carbonized bamboo, it is preferable that the thickness of the bamboo in a cross section perpendicular to the height direction is 2.0 to 5.0 mm. Furthermore, in the gasification method and the method for producing semi-carbonized bamboo, it is preferable that the outer diameter of the bamboo in a cross section perpendicular to the height direction is 50 mm or less.

[0014] This invention makes it possible to stably produce semi-carbonized bamboo that can efficiently gasify biomass fuel made from wood-based materials or herbaceous materials. In other words, a simple discrimination method can be used to produce semi-carbonized bamboo that can efficiently gasify biomass fuel made from wood-based materials or herbaceous materials.

[0015] Furthermore, in the carbonization step, it is preferable that the wood-based material or the herbaceous material is semi-carbonized with the superheated steam. This invention can further increase the amount of gas produced from semi-carbonized bamboo and biomass fuel, thereby further reducing the residue generated from semi-carbonized bamboo and biomass fuel. [Effects of the Invention]

[0016] This invention provides a gasification method for efficiently producing gas from biomass fuel material, a method for manufacturing semi-carbonized bamboo, and semi-carbonized bamboo. [Brief explanation of the drawings]

[0017] [Figure 1] Schematic diagram of torrefaction equipment. [Figure 2] Schematic diagram of an electric heater tubular pyrolysis gasification furnace. [Figure 3] A graph showing the change in mass of biomass fuel material gasified in an electric heater tubular pyrolysis gasifier versus pyrolysis temperature. [Figure 4] A graph showing the change in mass of biomass fuel material gasified in an electric heater tubular pyrolysis gasifier versus pyrolysis temperature. [Figure 5] A graph showing the amount of gas produced versus the pyrolysis temperature of biomass fuel gasified in an electric heater tubular pyrolysis gasifier. [Figure 6] Graph showing the gas composition versus pyrolysis temperature of biomass fuel gasified in an electric heater tubular pyrolysis gasifier. [Figure 7] A graph showing the change in mass of biomass fuel material gasified in an electric heater tubular pyrolysis gasifier versus pyrolysis temperature. [Figure 8] A graph showing the change in mass of biomass fuel material gasified in an electric heater tubular pyrolysis gasifier versus pyrolysis temperature. DETAILED DESCRIPTION OF THE INVENTION

[0018] An embodiment of the present invention will be described below with reference to the drawings. Figure 1 shows a schematic diagram of a torrefaction system 1, and Figure 2 shows a schematic diagram of an electric heater tubular pyrolysis gasifier 2. Figure 3 is a correlation diagram of the change in mass of biomass fuel versus pyrolysis temperature when biomass fuel produced from bamboo is gasified in the electric heater tubular pyrolysis gasifier 2. Figure 4 is a correlation diagram of the change in mass of biomass fuel versus pyrolysis temperature when biomass fuel produced from bamboo and cedar is gasified in the electric heater tubular pyrolysis gasifier 2. Figure 5 is a correlation diagram of the amount of gas produced versus pyrolysis temperature of biomass fuel when biomass fuel produced from bamboo and cedar is gasified in the electric heater tubular pyrolysis gasifier 2.

[0019] Figure 6 shows a correlation diagram of the gas composition of biomass fuel material versus pyrolysis temperature when biomass fuel material produced from bamboo and cedar is gasified in the electric heater tubular pyrolysis gasifier 2. Figure 7 shows a correlation diagram of the mass change versus pyrolysis temperature of biomass fuel material depending on the proportion of semi-carbonized bamboo mixed in. Figure 8 shows a correlation diagram of the mass change versus pyrolysis temperature of biomass fuel material when biomass fuel material mixed with other materials and bamboo is gasified in the electric heater tubular pyrolysis gasifier 2.

[0020] The torrefaction system 1 is an apparatus that generates superheated steam D from water H using an induction heating method and produces torrefied fuel S from bio-based raw material O using the generated superheated steam D. 1, the torrefaction system 1 is composed of a storage unit 11 that stores biomaterial O, a water feeder 12 that feeds water H to the storage unit 11, an air pipe 13 that connects the storage unit 11 and the water feeder 12, and an electromagnetic coil 14 that heats the water H passing through the air pipe 13 to produce superheated steam D. The torrefaction system 1 also includes a flow rate regulator 15 that measures the flow rate through the air pipe 13, a temperature regulator 16 that controls the temperature of the superheated steam D, and a control unit 17 that controls the generation of the superheated steam D.

[0021] The storage section 11 is a housing capable of storing the bio-raw material O, and is equipped inside with a steam insertion pipe 111 through which the superheated steam D generated in the air supply pipe 13 passes, a nozzle 112 that sprays the superheated steam D, and a mounting table 113 on which the bio-raw material O is placed.

[0022] The steam insertion pipe 111 is a heat-resistant pipe that communicates with the air supply pipe 13 and through which the superheated steam D flows. The steam insertion pipe 111 configured in this manner is appropriately disposed inside the accommodation unit 11. The nozzle 112 is a heat-resistant pipe that branches downward from the steam passage pipe 111, and is configured at its tip so that the superheated steam D flowing through the steam passage pipe 111 can be sprayed into the inside of the accommodation part 11.

[0023] The mounting table 113 is a high-temperature resistant metal mesh table located below the nozzle 112, and allows the biomaterials O to be arranged side by side. A plurality of such mounting tables 113 are provided in the height direction inside the storage unit 11. The steam insertion pipe 111 is appropriately arranged so that the nozzle 112 is located above the lower mounting table 113.

[0024] The water pump 12 discharges water H at room temperature into the air pipe 13 . The air supply pipe 13 is a conductive metal pipe, and its base end is connected to the water supply machine 12 and its tip is connected to the steam supply pipe 111. The air supply pipe 13 configured in this manner has a spirally wound electromagnetic coil 14 inserted therethrough. Note that the water H discharged from the water supply machine 12 is at room temperature, but this is not limiting, and hot water of about 80°C, for example, may be discharged.

[0025] The electromagnetic coil 14 is a conductive coil connected to a power source to form a circuit, and is wound spirally around the outer circumferential surface of the air pipe 13. By passing a current through the electromagnetic coil 14 configured in this manner, the air pipe 13, which is made of a conductive metal, can be superheated by electromagnetic induction. This causes the water H passing through the inside of the air pipe 13 to be superheated, and superheated steam D can be generated inside the air pipe 13.

[0026] The flow rate and temperature of the superheated steam D flowing inside the air supply pipe 13 are measured by the flow rate adjustment unit 15 and the temperature adjustment unit 16. Then, based on the measurement results of the flow rate adjustment unit 15 and the temperature adjustment unit 16, the control unit 17 controls the value of the current flowing through the electromagnetic coil 14 and the flow rate of the water H released from the water feeder 12 so that the superheated steam D reaches a predetermined temperature. In this way, the superheated steam D flowing inside the air supply pipe 13 is set to a desired flow rate and temperature. The control unit 17 also adjusts the flow rate of the superheated steam D flowing from the air supply pipe 13 to the steam insertion pipe 111, and the amount of superheated steam D sprayed from the nozzle 112 can also be adjusted.

[0027] Next, a production method for producing torrefied fuel S from biomaterial O using the torrefaction system 1 will be briefly described. When water H is released from water feeder 12 into air pipe 13, current is passed through electromagnetic coil 14, which causes an induced current to superheat air pipe 13, thereby heating the water H flowing through air pipe 13. As a result, superheated steam D at a temperature equal to or higher than the saturation temperature (100°C at normal pressure) can be generated from water H inside air pipe 13. The superheated steam D generated in this manner flows from air pipe 13 to steam insertion pipe 111 and is sprayed into the interior of storage section 11 from nozzle 112. The temperature of superheated steam D can be set as appropriate.

[0028] In this state where superheated steam D can be ejected into the housing unit 11, the fragmented biomaterial O is placed on the mounting table 113, and the superheated steam D is ejected from the nozzle 112 toward the biomaterial O for a predetermined period of time. By ejecting the superheated steam D in this manner, the biomaterial O is torrefied with the superheated steam D, and torrefied fuel S can be produced.

[0029] Here, the bio-raw material O may be bamboo or herbaceous materials such as sorghum, coffee grounds, rice husks, weeds, reeds, and grasses, which are organic resources derived from plants that do not grow into trees. Furthermore, the bio-raw material O may be a woody material other than herbaceous materials, such as organic resources derived from living organisms, including wood, including coniferous trees, broad-leaved trees, deciduous trees, fruit tree prunings, fast-growing trees, and driftwood. When the bio-raw material O to be semi-carbonized in the semi-carbonization system 1 is bamboo, the age of the bamboo is not limited.

[0030] Next, the electric heater tubular pyrolysis gasifier 2 used to verify the gasification of the torrefied fuel S produced from the bio-raw material O using the torrefaction system 1 in a laboratory test will be described below. As shown in Figure 2, the electric heater tubular pyrolysis gasification furnace 2 is composed of a hollow quartz tube 21, an electric heating unit 22 that adjusts the internal temperature of the quartz tube 21, a laboratory gasifying agent supply unit 23 that supplies carbon dioxide to the inside of the quartz tube 21, and a gas pack 24 that collects the gas generated in the quartz tube 21.

[0031] The quartz tube 21 is a tubular body made of quartz, and is configured to accommodate a gasification fuel material to be pyrolyzed inside. A measuring instrument (not shown) for measuring the mass of the accommodated gasification fuel material is also provided inside the quartz tube 21. One end of the quartz tube 21 is connected to a tube connected to the laboratory gasification agent supply unit 23, and the other end of the quartz tube 21 is connected to a tube for sending the gas generated inside the quartz tube 21 to a gas pack 24. The electric heating unit 22 is an electric heater for raising the temperature of the quartz tube 21 from the outside of the quartz tube 21, and is controlled so that the temperature inside the quartz tube 21 can be raised at 400° C. / hour.

[0032] The laboratory gasifying agent supply unit 23 is a cylinder filled with carbon dioxide, which is introduced as a gasifying agent into the quartz tube 21. The flow rate of carbon dioxide introduced from the laboratory gasifying agent supply unit 23 into the quartz tube 21 is controlled to be constant.

[0033] A method for generating the generated gas G from gasification fuel material such as semi-carbonized fuel S using the electric heater tubular pyrolysis gasification furnace 2 configured as above will now be described in detail. First, gasification fuel material such as semi-carbonized fuel S is pulverized in a Wonder Blender pulverizer to particles of 100 μm or less, and 100 mg±10 mg of the pulverized material is loaded into a quartz tube 21. Then, a laboratory gasifying agent supply unit 23 filled with carbon dioxide to be introduced into the quartz tube 21 is connected to the quartz tube 21, and the flow rate of the carbon dioxide to be introduced into the quartz tube 21 is set.

[0034] Next, the electric heating unit 22 is controlled to raise the temperature inside the quartz tube 21. The temperature raising rate of the quartz tube 21 was set to approximately 400°C / H. By raising the internal temperature of the quartz tube 21 in this manner, the gasification fuel material is pyrolyzed in the quartz tube 21, and the generated gas G is generated. The generated gas G generated in the quartz tube 21 is air-cooled in the furnace core tube and tube (not shown) and collected as fly ash components in a strainer (not shown), and then collected in the gas pack 24. The amount of the generated gas G collected in the gas pack 24 can be measured in the electric heater tubular pyrolysis gasifier 2. The components of the generated gas G collected in the gas pack 24 can be analyzed using gas chromatography, infrared spectroscopy, or the like.

[0035] Furthermore, the change in mass of the gasification fuel material contained in the quartz tube 21 in response to temperature changes in the quartz tube 21 can be measured at any time using a measuring instrument that measures the mass of the contained gasification fuel material. The change in mass of the gasification fuel material was measured at 100°C intervals while the internal temperature of the quartz tube 21 was from room temperature to 200°C, and then at 50°C intervals from 200°C up to 800°C. The amount of generated gas G collected in the gas pack 24 and the components of the generated gas G were also measured as appropriate.

[0036] In the following, a method for producing the torrefied fuel S using the torrefaction system 1 described above, and gasification of the gasification fuel material using the electric heater tubular pyrolysis gasification furnace 2 will be described. Bamboo materials were used as samples of bio-raw material O. Two types of bamboo materials were prepared: bamboo with the bark partially attached to the base, with the outer diameter of the culm (straight culm) in a cross section perpendicular to the height being 50 mm or less, or with a wall thickness in a cross section perpendicular to the height being 2.0 to 5.0 mm (referred to as Sample A); and bamboo with the bark partially removed from the base, with an outer diameter greater than 50 mm (60 mm or greater), or with a wall thickness of 6.0 mm or greater (referred to as Sample B).

[0037] Here, sample A was broken down into small pieces and dried indoors, and then semi-carbonized using semi-carbonization system 1 with superheated steam at a temperature of 300°C to produce semi-carbonized material (hereinafter referred to as sample A1). The mass of sample A1 is 30% to 50% of the mass of sample A. For example, if the mass of sample A is 6g and the mass of semi-carbonized sample A1 is 4g, the mass of sample A1 is reduced by 33.4% compared to sample A.

[0038] Similarly, Sample B was divided into small pieces and dried indoors, and then semi-carbonized using the semi-carbonization system 1 with superheated steam at a temperature of 300 degrees to produce semi-carbonized material (hereinafter referred to as Sample B1). The mass of Sample B1 was 30% to 50% of the mass of Sample B.

[0039] Next, the thus-produced Sample A1 and Sample B1, and a mixture of Sample A1 and Sample B1, were gasified using an electric heater tubular pyrolysis gasification furnace 2. Specifically, sample A1 was pulverized to particles of 100 μm or less using a Wonder Blender pulverizer, and 100 mg±10 mg of the pulverized sample was filled into a quartz tube 21. The quartz tube 21 was connected to a laboratory gasifying agent supply unit 23 filled with carbon dioxide to be introduced into the quartz tube 21, and the flow rate of the carbon dioxide to be introduced into the quartz tube 21 was set.

[0040] Next, the electric heating unit 22 is controlled to raise the temperature inside the quartz tube 21. The temperature raising rate of the quartz tube 21 is set to about 400°C / Hr. By raising the internal temperature of the quartz tube 21 in this manner, the sample A1 is thermally decomposed in the quartz tube 21, and a product gas is generated. The product gas generated in the quartz tube 21 is air-cooled in a furnace core tube and a tube (not shown), and is collected as fly ash components in a strainer (not shown), and then collected in a gas pack 24.

[0041] Similarly, sample B1 was pulverized in a Wonder Blender pulverizer to particles of 100 μm or less, and 100 mg±10 mg of the pulverized material was filled into a quartz tube 21 and gasified under the same conditions, and the generated gas was collected. Samples A1 and B1 were pulverized in a Wonder Blender pulverizer to particles of 100 μm or less and mixed in equal amounts. 100 mg±10 mg of the mixed samples A1 and B1 were then filled into a quartz tube 21 and gasified under the same conditions, and the resulting gas was collected.

[0042] During this gasification process, the mass changes of Sample A1, Sample B1, and a mixture of Sample A1 and Sample B1 contained in quartz tube 21 with respect to temperature changes were investigated (see FIG. 3). The mass changes of Sample A1, Sample B1, and Sample A1 and Sample B1 were measured at 100°C intervals from room temperature to 200°C when the internal temperature of quartz tube 21 was changed, and then at 50°C intervals from 200°C to 800°C.

[0043] Sample A1's mass decreased gradually from 0°C to 250°C, then rapidly decreased between 250°C and 450°C. Then, the mass decreased gradually from 450°C to 700°C, but rapidly decreased between 700°C and 800°C. At 450°C, the mass of sample A1 was approximately 50% of the mass before gasification, at 700°C it was approximately 40% of the mass before gasification, and at 800°C it was approximately 8% of the mass before gasification.

[0044] These results show that in sample A1, the first pyrolysis reaction and pyrolysis gasification reaction are promoted at temperatures between 300 and 500°C and between 700 and 800°C, resulting in a rapid decrease in mass. A more notable feature is that sample A1 experiences a rapid decrease in mass at temperatures between 700 and 800°C, suggesting that gas is being generated.

[0045] 3, similar to sample A1, sample B1 exhibits a gradual mass decrease from 0°C to 250°C, followed by a rapid mass decrease between 250°C and 450°C. Then, the mass decreases gradually between 450°C and 800°C. That is, the mass decrease curve of sample B1 housed in quartz tube 21 versus the internal temperature of quartz tube 21 becomes an inverted S-shape as the temperature increases. At 450°C, the mass of sample B1 is approximately 30% of the mass before gasification, and at 800°C, it is approximately 20% of the mass before gasification.

[0046] From this, it can be seen that in sample B1, the first reaction of pyrolysis is promoted at 300 to 500°C, causing a rapid decrease in mass, but unlike sample A1, the pyrolysis gasification reaction hardly occurs at 700 to 800°C, causing almost no change in mass.

[0047] When Sample A1 and Sample B1 were mixed in equal parts, the mass decreased gradually from 0°C to 250°C, as with Sample A1, but then decreased rapidly between 250°C and 450°C.The mass then decreased gradually from 450°C to 700°C, but then decreased rapidly between 700°C and 800°C.The mass of Sample A1 was approximately 30% of the mass before gasification at 450°C, approximately 20% at 700°C, and approximately 5% at 800°C.

[0048] This shows that when Sample A1 and Sample B1 are mixed in an equal ratio, the first pyrolysis reaction and pyrolysis gasification reaction are promoted at temperatures between 300 and 450°C and between 700 and 800°C, resulting in a rapid decrease in mass. That is, Sample A1 and Sample B1 can be efficiently pyrolyzed at temperatures between 300 and 450°C, and, unlike Sample B1, gasification can also be promoted at temperatures between 700 and 800°C. Therefore, when Sample A1 and Sample B1 are mixed in an equal ratio, the mass can be reduced at gasification temperatures between 700 and 800°C compared to Sample B1 alone, and therefore the residue from the gasification reaction can be reduced.

[0049] When Sample A1 and Sample B1 were mixed in a 50 / 50 ratio, the mass ratio at 800°C was approximately the same as when only Sample A1 was used. Furthermore, the mass loss curve when Sample A1 and Sample B1 were mixed in a 50 / 50 ratio was not intermediate between the mass loss curves when only Sample A1 and Sample B1 were used, suggesting that Sample A1 and Sample B1 interact with each other when mixed.

[0050] Next, the mass change and gas production amount when sample A1 was mixed with other biomass fuel materials were examined. First, a method for producing the biomass fuel material to be mixed with sample A1 will be described.

[0051] Cedar was used as the raw material for the biomass fuel to be mixed with Sample A1. The cedar was broken down into small pieces and dried indoors, after which it was torrefied using the torrefaction system 1 with superheated steam at a temperature of 300 degrees to produce torrefied material (hereinafter referred to as Sample C1). Sample C1 has a brown surface and a carbon content of approximately 55%.

[0052] Similarly, the cedar was broken down into small pieces and dried indoors, after which it was carbonized at temperatures of 400°C or 550°C using the semi-carbonization system 1 to produce carbonized materials (hereinafter referred to as Sample C2 and Sample C3). The surfaces of Sample C2 and Sample C3 are darker than those of Sample C1, and the carbon content is approximately 60% and 79%, respectively.

[0053] Samples C1, C2, and C3 thus produced were pulverized in a Wonder Blender pulverizer to particles of 100 μm or less. Then, 100 mg±10 mg of each of Samples C1, C2, and C3 was filled into a quartz tube 21 and gasified under the same conditions, and the generated gas was collected.

[0054] In addition, Sample C1, Sample C2, and Sample C3 were mixed with Sample A1 so that the volume ratios were approximately the same, and 100 mg±10 mg of the mixture of Sample A1 and Sample C1, the mixture of Sample A1 and Sample C2, and the mixture of Sample A1 and C3 were filled into a quartz tube 21, gasified under the same conditions, and the produced gas was collected.

[0055] As described above, in the fuel material gasification process, the mass change and gas production amount of each mixture contained in the quartz tube 21 were investigated in response to temperature changes (see Figures 4 and 5). The mass change and gas production amount were measured at 100°C intervals from room temperature to 200°C when the internal temperature of the quartz tube 21 was changed, and then at 50°C intervals from 200°C to 800°C.

[0056] 5 illustrates the amount of gas generated from a mixture of Sample A1 and Sample C1, which are mixed at approximately the same volume ratio, and Sample C1. Note that Fig. 5 shows the amount of gas generated from the mixture of Sample A1 and Sample C1 and Sample C1 at each temperature, assuming that the amount of gas generated at 800°C when the mixture of Sample A1 and Sample C1 is gasified is 1.

[0057] 4, the mass of samples C1 and C2 decreases gradually from 0° C. to 250° C., then decreases rapidly between 250° C. and 450° C., and then decreases gradually between 450° C. and 800° C. That is, the mass decrease curves of samples C1 and C2 housed in the quartz tube 21 versus the internal temperature of the quartz tube 21 form an inverted S-shape as the temperature increases.

[0058] The mass of sample C1 was approximately 25% of the mass before gasification at 450°C, and approximately 13% of the mass before gasification at 800°C. In contrast, the mass of sample C2 was approximately 50% of the mass before gasification at 450°C, and approximately 32% of the mass before gasification at 800°C.

[0059] Furthermore, as shown in Figure 4, sample C3 gradually loses mass from 0°C to 800°C. At 450°C, the mass of sample C3 is approximately 85% of the mass before gasification, and at 800°C, it is approximately 69% of the mass before gasification. From these results, it is thought that in samples C2 and C3, which have high temperatures during superheat treatment and a high carbon content, the amount of gas generated during pyrolysis gasification is drastically reduced due to a decrease in volatile components and an increase in fixed carbon, resulting in a large amount of residue remaining.

[0060] On the other hand, the fuel material obtained by mixing Samples C1, C2, and C3 with Sample A1 exhibits a substantially similar mass loss curve with respect to the internal temperature of the quartz tube 21. Specifically, the mass decreases gradually from 0°C to 250°C, and then decreases rapidly between 250°C and 450°C. The mass also decreases gradually from 450°C to 650°C, but then decreases rapidly between 650°C and 800°C.

[0061] More specifically, the mass of a mixture of Sample A1 and Sample C1, in which Sample A1 and Sample C1 have approximately the same volume ratio, is approximately 35% of the mass before gasification at 450°C, and approximately 25% at 700°C.The mass of a mixture of Sample A1 and Sample C1, in which Sample A1 and Sample C1 have approximately the same volume ratio, is approximately 5% of the mass before gasification at 800°C.

[0062] That is, at 800°C, the mass reduction rate of the mixture of Sample A1 and Sample C1 containing 50% Sample A1 by volume relative to the mass of Sample C1 alone is 1.8%.Furthermore, at 800°C, the mass reduction rate of the mixture of Sample A1 and Sample C1 containing 50% Sample A1 by volume relative to the mass of Sample C1 alone is 2.6%.

[0063] As described above, in the fuel material in which Sample A1 and Sample C1 are mixed in approximately the same volume ratio, the pyrolysis gasification reaction is accelerated at 700 to 800°C, and the mass is rapidly reduced, compared to the case in which Sample C1 alone is used. This allows for a reduction in residue compared to the case in which Sample C1 alone is gasified. Therefore, efficient gasification is possible.

[0064] Furthermore, the mass of the mixture of Sample A1 and Sample C2 was approximately 50% of the mass before gasification at 450°C, and approximately 31% at 700°C. The mass of the mixture of Sample A1 and Sample C2 was approximately 18% of the mass before gasification at 800°C. In other words, at 800°C, the mass reduction rate of the mixture of Sample A1 and Sample C2 relative to the mass of Sample C2 alone was 1.8%.

[0065] Furthermore, the mass of the mixture of Sample A1 and Sample C3 was approximately 58% of the mass before gasification at 450°C, and approximately 46% at 700°C.The mass of the mixture of Sample A1 and Sample C3 was approximately 17% of the mass before gasification at 800°C.In other words, at 800°C, the mass reduction rate of the mixture of Sample A1 and Sample C3 relative to the mass of Sample C2 alone was 4.1%.

[0066] As described above, samples C2 and C3 have low volatile components and high fixed carbon, resulting in extremely low gas generation rates during pyrolysis gasification. However, when sample C2 or C3 is mixed with sample A1, the first reaction is promoted at 250°C to 450°C, and the pyrolysis gasification reaction is promoted at 700°C to 800°C, resulting in rapid mass reduction. Therefore, even samples C2 and C3, which are unsuitable for gasification, can be gasified reliably and efficiently by mixing them with sample A1, resulting in reduced residue.

[0067] 5, when sample C1 is gasified, the amount of gas generated increases rapidly between 250°C and 450°C, and then increases gradually from 450°C. In contrast, when a mixture of equal amounts of sample A1 and sample C1 is gasified, the amount of gas generated increases rapidly between 250°C and 450°C, and then increases gradually from 450°C to 600°C, just like sample C1. It can then be seen that the amount of gas generated increases rapidly from 600°C to 800°C.

[0068] This suggests that the first reaction is promoted at 250°C to 450°C, and the pyrolysis gasification reaction is promoted at 600°C to 800°C, resulting in an increase in the amount of gas produced in each temperature range. This coincides with the decrease in mass of the mixture of Sample A1 and Sample C1 contained in the quartz tube 21 when the pyrolysis temperature is increased (see Figures 4 and 5). In other words, it is believed that mixing Sample A1 with Sample C1 can increase the amount of gas produced and reduce the residue caused by gasification.

[0069] Furthermore, the gas components at each temperature range are compared when a mixture of Sample A1 and Sample C1, in which Sample A1 and Sample C1 are mixed in approximately equal volumes, is gasified with Sample C1 (see Figure 6). 6(a) shows the composition ratio of the components in the gas produced by thermally decomposing a mixture of Sample A1 and Sample C1, in which Sample A1 and Sample C1 are mixed in approximately equal volumes, versus the thermal decomposition temperature, while FIG. 6(b) shows the composition ratio of the components in the gas produced by thermally decomposing Sample C1, versus the thermal decomposition temperature.

[0070] When sample C1 was mixed with sample A1 and pyrolyzed, the amount of gas generated at 700 to 800°C was significantly increased compared to when sample C1 alone was pyrolyzed. This is consistent with the results in Figure 5.

[0071] Furthermore, by mixing Sample C1 with Sample A1 and pyrolyzing the mixture, the composition of the generated gas at each pyrolysis temperature changed significantly. Specifically, when sample C1 was pyrolyzed, a large amount of carbon monoxide (CO) was produced in the first reaction (300-450°C), as shown in Figure 6(b). Furthermore, although the amounts were smaller than those of carbon monoxide, hydrogen (H2), ethane (C2H6), and propane (C3H8) were also produced from sample C1. In contrast, in the pyrolysis gasification reaction (650-800°C), a smaller amount of hydrogen (H2) than in the first reaction and an amount of carbon monoxide similar to that of hydrogen were produced.

[0072] On the other hand, when sample C1 was mixed with sample A1 and pyrolyzed, a relatively large amount of hydrogen (H2) and ethane (C2H6) was produced in the first reaction (300-450°C), along with a small amount of carbon monoxide (CO). Furthermore, in the pyrolysis gasification reaction (650-800°C), sufficient amounts of hydrogen (H2), methane (CH4), and carbon monoxide were produced compared to when sample C1 was used alone.

[0073] The first reaction (300-450°C) during pyrolysis of sample C1 mixed with sample A1 will be described in more detail. When sample C1 is mixed with sample A1 and pyrolyzed, hydrogen (H2) is produced from 250°C, along with smaller amounts of carbon monoxide (CO) and methane (CH4). The amount of hydrogen (H2) produced peaks at 300-350°C. Then, at 350-400°C, the amount of hydrogen (H2) produced decreases significantly, and the amounts of carbon monoxide (CO) and methane (CH4) produced also decrease. Instead, the amount of ethane (C2H6) produced increases, and the amount of ethane (C2H6) produced peaks at 400-450°C.

[0074] The fact that the amounts of hydrogen (H2) and ethane (C2H6) produced peak at 350°C and 450°C is consistent with the mass change shown in Figure 4. That is, when a mixture of equal amounts of Sample A1 and Sample C1 is pyrolyzed, the mass decrease is consistent with the stepwise change between 300-400°C and 400-450°C (see Figure 4).

[0075] Furthermore, when a mixture of equal amounts of Sample A1 and Sample C1 is pyrolyzed, the amount of generated gas at 300 to 450°C is approximately the same as the amount of generated gas when only Sample C1 is pyrolyzed. This means that by mixing Sample C1 with Sample A1, it is possible to generate generated gas with high thermal efficiency.

[0076] From the above, when a mixture of Sample C1 and an equal amount of Sample A1 is pyrolyzed, hydrogen (H2) and methane (CH4) are produced in the first reaction (300-450°C), which are more thermally efficient than carbon monoxide (CO), compared to when only Sample C1 is pyrolyzed.

[0077] Furthermore, in the pyrolysis gasification reaction (700-800°C), sufficient amounts of hydrogen (H2), methane (CH4), and carbon monoxide (CO) can be produced compared to sample C1 alone, which produces almost no gas. This means that in the pyrolysis gasification reaction, combustible gases can be produced efficiently and residues can be reduced. Therefore, fuel materials can be consumed efficiently.

[0078] Therefore, by mixing Sample C1 with Sample A1, not only can the amount of generated gas be increased and the residue reduced, but also generated gas with higher thermal efficiency can be produced. Therefore, by mixing biomass fuel with torrefied bamboo in the same ratio, generated gas can be produced more efficiently and with a higher calorific value.

[0079] Furthermore, as can be seen from Samples C2 and C3, even if a material is not suitable for gasification by itself, by mixing it with Sample A1, the pyrolysis gasification reaction can be promoted. In other words, even if the material has a high carbon content, by mixing it with the semi-carbonized Sample A1, it can be efficiently gasified.

[0080] Next, an experiment was conducted in which the volume ratio of sample A1 to sample C1 was changed. Specifically, sample A1 was mixed with sample C1 so that the volume of sample A1 was approximately 15%, 25%, 35%, and 45% of the total volume. 100 mg ± 10 mg of the mixture of sample A1 and sample C1 was filled into a quartz tube 21 and gasified under the same conditions. The mass change of each mixture contained in the quartz tube 21 with respect to temperature change was investigated (see FIG. 7). The mass change was measured at 100°C intervals from room temperature to 200°C when the internal temperature of the quartz tube 21 was changed, and then at 50°C intervals from 200°C to 800°C.

[0081] In the mixture of Sample A1 and Sample C1, where the volume of Sample A1 is 15% of the total volume, the mass decreases gradually from 0°C to 250°C, then decreases rapidly between 250°C and 450°C, and then decreases gradually between 450°C and 800°C, as shown in Figure 7.

[0082] Similarly, the mixture of Sample A1 and Sample C1, in which the volume of Sample A1 accounts for 25% of the total volume, showed a gradual decrease in mass from 0°C to 250°C, followed by a rapid decrease in mass between 250°C and 450°C. The mass then decreased gradually between 450°C and 650°C, followed by a further decrease in mass between 650°C and 800°C. That is, when the volume of Sample A1 accounts for less than 25% of the total volume, the mass decrease curve of the mixture of Sample A1 and Sample C1 contained in the quartz tube 21 versus the internal temperature of the quartz tube 21 exhibited an inverted S-shape as the temperature increased. However, when the volume of Sample A1 accounted for 25% of the total volume, a clear decrease in mass was observed between 650°C and 800°C.

[0083] In contrast, when the volume of sample A1 is 35% and 45% of the total volume, the mass decreases gradually from 0°C to 250°C, and then decreases rapidly between 250°C and 450°C.The mass also decreases gradually from 450°C to 700°C, but then decreases rapidly between 700°C and 800°C.

[0084] More specifically, the mass of a mixture of Sample A1 and Sample C1 containing 35% Sample A1 by volume is approximately 40% of the mass before gasification at 450°C, and approximately 27% at 700°C.The mass of a mixture of Sample A1 and Sample C1 containing 35% Sample A1 is approximately 13% of the mass before gasification at 800°C.

[0085] Similarly, the mass of a mixture of Sample A1 and Sample C1 containing 45% Sample A1 by volume is approximately 30% of the mass before gasification at 450°C, and approximately 15% at 700°C.The mass of a mixture of Sample A1 and Sample C1 containing 35% Sample A1 is approximately 5% of the mass before gasification at 800°C.

[0086] This shows that when the volume of sample A1 is 25% or more of the total volume, the mass of the mixture of sample A1 and sample C1 contained in quartz tube 21 relative to the internal temperature of quartz tube 21 decreases rapidly from 700 to 800°C. In other words, when sample A1 and sample C1 are mixed so that the volume of sample A1 is 25% or more of the total volume, gasification is promoted from 700 to 800°C.

[0087] Next, peach prunings, sorghum, and rice husks were also semi-carbonized under the same conditions as those for the cedar (sample C1), and a gasification experiment was conducted using the electric heater tubular pyrolysis gasification furnace 2. In more detail, only peach pruning wood that had been torrefied using superheated steam, and a mixture of equal amounts of peach pruning wood that had been torrefied using superheated steam and bamboo wood (sample A1) that had been torrefied using superheated steam were used as fuel materials, and gasification experiments were conducted using an electric heater tubular pyrolysis gasification furnace 2 to examine the change in mass of the fuel materials (see Figure 8(a)).

[0088] Similarly, gasification experiments were conducted using only sorghum torrefied using superheated steam, and a mixture of equal amounts of sorghum torrefied using superheated steam and bamboo torrefied using superheated steam (sample A1) as fuel materials, using the electric heater tubular pyrolysis gasification furnace 2 to examine the change in mass of the fuel materials (see Figure 8(b)).

[0089] In addition, gasification experiments were conducted using only rice husks that had been torrefied using superheated steam, and a mixture of equal amounts of rice husks that had been torrefied using superheated steam and bamboo material (sample A1) that had been torrefied using superheated steam as fuel materials, using an electric heater tubular pyrolysis gasification furnace 2 to examine the change in the mass of the fuel material (see Figure 8(c)).

[0090] When peach pruning wood, sorghum, and rice husks that have been torrefied using superheated steam are gasified, the mass of each material at 800°C is approximately 30% of the mass before gasification, as shown in Figures 8(a) to 8(c). For this reason, these materials are considered unsuitable as fuel materials for gasification on their own.

[0091] However, when a mixture of peach pruning, sorghum, and rice husks torrefied using superheated steam and bamboo (Sample A1) torrefied using superheated steam was gasified, the mass rapidly decreased between 700 and 800°C, as shown in Figures 8(a) to 8(c). Specifically, the masses of peach pruning, sorghum, and rice husks were approximately 5%, 10%, and 15%, respectively, of the mass before gasification, and mixing with Sample A1 accelerated the pyrolysis gasification reaction. This suggests that Sample A1 can efficiently gasify biomass feedstocks prepared by carbonizing woody and herbaceous materials.

[0092] The composition of woody or herbaceous materials varies depending on the material (type). Furthermore, even the same material (type) can have different compositions due to differences in growing environment, etc. Therefore, even when the same woody or herbaceous material is carbonized or semi-carbonized, variations in the biomass fuel produced can occur. However, even if variations in the biomass fuel occur, the residue generated from the biomass fuel can be reduced by mixing it with semi-carbonized bamboo and gasifying it. In other words, this method can efficiently generate gas from biomass fuel.

[0093] In this way, the process involves a carbonization process in which woody or herbaceous materials such as bamboo, cedar, peach pruning, sorghum, and rice husks are carbonized or semi-carbonized to produce biomass fuel; a semi-carbonization process in which bamboo (bio-raw material O) is semi-carbonized to produce semi-carbonized bamboo; and a gasification process in which the biomass fuel and semi-carbonized bamboo are mixed in a predetermined ratio to produce fuel, which is then fed into a gasification device that releases gas and the fuel is gasified.In the semi-carbonization process, gas can be efficiently produced from biomass fuel made from woody or herbaceous materials by using a gasification method in which the bamboo is superheated with superheated steam.

[0094] More specifically, in the gasification process for gasifying biomass fuel, the amount of gas generated from semi-carbonized bamboo and biomass fuel can be increased at 700-800°C, where biomass fuel residue is likely to be generated. This reduces the amount of residue generated from semi-carbonized bamboo and biomass fuel compared to when only biomass fuel is gasified (see Figures 3, 4, and 8).

[0095] In addition, in the gasification process, the volume of semi-carbonized bamboo (semi-carbonized fuel SS) fed into the gasifier is preferably 25 to 50% of the fuel material, which increases the amount of gas generated and also makes the composition of the gas generated a higher calorific value (see Figure 7).

[0096] More specifically, if the semi-carbonized bamboo accounts for less than 25% of the total volume, the mass of the mixture cannot be sufficiently reduced at temperatures between 650 and 800°C, which correspond to the pyrolysis gasification reaction. However, if the semi-carbonized bamboo accounts for 25% or more of the total volume, gasification can be promoted at temperatures between 650 and 800°C, and the mass of the mixture can be reduced.

[0097] On the other hand, if more than 50% semi-carbonized bamboo is mixed, the proportion of biomass fuel that would produce residue if gasified alone decreases, resulting in a lower gasification efficiency of the biomass fuel. For this reason, it is preferable to mix semi-carbonized bamboo with biomass fuel at a ratio of 50% or less.

[0098] Furthermore, when the proportion of semi-carbonized bamboo in the total volume is reduced, the mass loss curve at 100 to 550°C tends to resemble the shape of the mass loss curve for biomass fuel material not mixed with semi-carbonized bamboo. In other words, by reducing the mixing ratio of semi-carbonized bamboo, the gas composition generated by gasification is expected to become similar to that of biomass fuel material. In other words, it is expected that the generation of thermally efficient hydrogen and other gases will be suppressed. In contrast, by increasing the volume of semi-carbonized bamboo to 25% or more, the generation of thermally efficient gas can be promoted.

[0099] Furthermore, by torrefying the bamboo with superheated steam set at 300°C in the torrefaction process, the amount of gas generated from the torrefied bamboo and biomass fuel can be reliably increased and the residue generated from the torrefied bamboo and biomass fuel can be reliably reduced (see Figures 3, 4, and 5). Therefore, gas with a high calorific value can be reliably and efficiently generated from biomass fuel made from woody or herbaceous materials.

[0100] In addition, by reducing the mass of the bamboo material by 30 to 50% compared to before the semi-carbonization process, the amount of gas produced from the semi-carbonized bamboo material and biomass fuel material can be increased at a gasification temperature of 700 to 800°C, thereby further reducing the residue produced from the semi-carbonized bamboo material and biomass fuel material.

[0101] For example, if the mass of semi-carbonized bamboo is reduced by less than 30% compared to the mass of the bamboo before semi-carbonization, the moisture content of the semi-carbonized bamboo will be high, which will result in poor gasification efficiency and insufficient promotion of gasification of the biomass fuel mixed with the semi-carbonized bamboo.

[0102] Furthermore, if the mass of semi-carbonized bamboo is reduced by 50% or more compared to the mass of the bamboo before semi-carbonization, the carbon content of the semi-carbonized bamboo will increase, which will result in the bamboo being unable to be sufficiently gasified, and the gasification of the biomass fuel mixed with the semi-carbonized bamboo will not be sufficiently promoted.

[0103] In contrast, if the mass of the semi-carbonized bamboo is reduced to within the range of 30 to 50% of the mass of the bamboo before semi-carbonization, the semi-carbonized bamboo can be sufficiently gasified and the gasification of the mixed biomass fuel can be sufficiently promoted.

[0104] Furthermore, in the gasification method and the method for manufacturing semi-carbonized bamboo, the thickness of the bamboo in a cross section perpendicular to the height direction is 2 to 5.0 mm, and in the gasification method and the method for manufacturing semi-carbonized bamboo, the outer diameter of the bamboo in a cross section perpendicular to the height direction is 50 mm or less.

[0105] This allows for the stable production of semi-carbonized bamboo that can efficiently gasify biomass fuel made from wood or herbaceous materials.In other words, a simple discrimination method allows for the production of semi-carbonized bamboo that can efficiently gasify biomass fuel made from wood or herbaceous materials (see Figure 3).

[0106] Furthermore, by semi-carbonizing wood or herbaceous materials with superheated steam in the carbonization process, the amount of gas produced from the semi-carbonized bamboo and biomass fuel can be further increased, thereby further reducing the residue produced from the semi-carbonized bamboo and biomass fuel.

[0107] The wood-based material is a biologically derived organic resource consisting of wood, and may be, for example, coniferous trees, broad-leaved trees, deciduous trees, fruit tree prunings, fast-growing trees, driftwood, and the like. Herbaceous materials are organic resources derived from plants that do not grow into trees, and may be, for example, sorghum, bamboo, coffee grounds, rice husks, weeds, reeds, and grass plants. [Explanation of symbols]

[0108] O...Bio-based raw materials S…Semi-carbonized fuel

Claims

1. a carbonization step of carbonizing or semi-carbonizing woody or herbaceous materials to produce biomass fuel material; a semi-carbonization process for semi-carbonizing bamboo to produce semi-carbonized bamboo; The biomass fuel material and the semi-carbonized bamboo material are mixed in a predetermined ratio to form a fuel material, which is then fed into a gasification device that releases gas, and a gasification process is carried out in which the fuel material is gasified. In the semi-carbonization process, the bamboo material is heated with superheated steam. Gasification method.

2. In the gasification process, the volume of the semi-carbonized bamboo material fed into the gasification device is 25 to 50% of the fuel material. The gasification method according to claim 1 .

3. In the semi-carbonization process, the bamboo material was semi-carbonized with the superheated steam set at 300 ° C. The gasification method according to claim 1 or 2.

4. In the semi-carbonization process, the mass of the bamboo material was reduced by 30 to 50% compared to the mass before semi-carbonization. The gasification method according to claim 1 or 2.

5. The thickness of the bamboo material in a cross section perpendicular to the height direction is 2.0 to 5.0 mm. The gasification method according to claim 1 or 2.

6. The outer diameter of the cross section perpendicular to the height direction of the bamboo material is 50 mm or less. The gasification method according to claim 1 or 2.

7. In the carbonization step, the wood-based material or the herbaceous material is semi-carbonized with the superheated steam. The gasification method according to claim 1 or 2.

8. Bamboo is heated to 300°C with superheated steam to semi-carbonize it. Manufacturing method for semi-carbonized bamboo.

9. The bamboo material is heated with the superheated steam until the mass of the bamboo material is reduced by 30 to 50% compared to the mass of the bamboo material before semi-carbonization. The method for producing semi-carbonized bamboo material according to claim 8.

10. The thickness of the bamboo material is 2.0 to 5.0 mm. The method for producing semi-carbonized bamboo material according to claim 8 or claim 9.

11. The outer diameter of the bamboo material is 50 mm or less. The method for producing semi-carbonized bamboo material according to claim 8 or claim 9.

12. It is 30 to 50% of the mass of the raw bamboo material. Semi-carbonized bamboo material.

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