JP2009051985A - Manufacturing method of biomass-based molded fuel - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To manufacture molded fuels having various shapes and sizes, which are obtained without dry distillation of a biomass at a predetermined temperature and without addition of a binder and which have high mechanical strengths and good storage properties. <P>SOLUTION: First, an aqueous solution or suspension 13 of slaked lime is stuck to a biomass raw material 12 consisting of biomass powders or a biomass pulverent. Next, into the biomass raw material 12 attached with this aqueous solution or suspension 13 of the slaked lime a coal raw material 14 having a particle size of ≤3 mm is added in a proportion of ≤100% by mass per 100% by mass of the biomass raw material and heated at a temperature of 80-100°C. Further, the heated mixture 16 is applied with a pressure of 100-500 MPa under a temperature of 80-100°C using a double roll type press 17 to heat and mold into a briquette or plate. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a method for producing a biomass-type molded fuel in which a biomass raw material such as agricultural / forestry waste, unused plant, plant fiber or the like is a main component and a coal raw material is mixed with the biomass raw material.

  The biomass replacement rate for coal-fired thermal power plants has been limited to about 3% in previous demonstration experiments. It is difficult to efficiently mix and pulverize coal and biomass with greatly different pulverization characteristics at the same time using existing roll mills and other coal pulverization equipment. There are technical and economic problems. In addition, even if the substitution rate can be increased by using a pulverizer dedicated to biomass, there remains a technical problem for efficiently co-firing coal and biomass having greatly different physical properties and combustibility.

In order to eliminate these points, 3% by weight or more of biomass dry distillate composed of rice husks, wood chips and the like is mixed with powdered coal having a volatile content of 15% or more to improve ignitability and combustion sustainability. A biomass dry distillate composite coal briquette fuel that can reduce the generation of soot during combustion has been disclosed (for example, see Patent Document 1). In this biomass dry distillate composite coal briquette fuel, first, coal is pulverized into a powder form having a particle shape of 3 mm or less. Next, it is a dry-distilled product in which biomass such as rice husks and wood chips is dry-distilled at a low temperature of about 300 to 650 ° C. and part of the volatile matter remains to improve ignitability and combustibility. The body is mixed so that the particles are uniformly dispersed at a weight ratio of 3% or more with coal, and then formed into briquettes. In the above mixed state, a lot of biomass dry matter is scattered between coal particles. When coal with a high sulfur content is used, a powdery desulfurizing agent containing calcium, magnesium and the like is added to briquette fuel to further reduce the generation of sulfur oxides during combustion. That is, when limestone (CaCO ₃ ) or slaked lime (Ca (OH) ₂ ) is added and mixed as a desulfurizing agent during briquette production, sulfur oxide generated from coal during combustion is fixed as calcium sulfide, and the sulfur oxide in the atmosphere Emissions can be reduced. In addition, molasses and clay are mixed as a binder.
Japanese Patent Laying-Open No. 2004-331928 (Claims 1 and 2, paragraphs [0005] and [0006], FIG. 1)

However, in the biomass dry distillate composite coal briquette fuel shown in the above-mentioned conventional patent document 1, it is necessary to dry-distill at a low temperature of about 300 to 650 ° C. in advance before mixing biomass such as rice husk and wood chips with coal. . Moreover, in the biomass dry distillation composite coal briquette fuel shown in the above-mentioned conventional patent document 1, limestone (CaCO ₃ ) or slaked lime (Ca (OH) ₂ ) is used only as a powdery (solid) desulfurization agent, In addition, since it is not heated during molding, if a binder such as molasses or clay is not mixed, the briquette strength decreases and the briquette becomes brittle, and the storage and transportability of the briquette also deteriorate. there were. Furthermore, in the biomass dry distillate composite coal briquette fuel shown in the above-mentioned conventional patent document 1, it is described that 3% by weight or more of biomass dry distillate is mixed with coal. There is also a problem that only about wt% is mixed, and the rate of substitution from coal to biomass is still low, and the generation of global warming gas cannot be reduced.

  The first object of the present invention is to obtain various shapes and sizes having high mechanical strength and good storage properties without previously carbonizing biomass at a predetermined temperature and without adding a binder. It is providing the manufacturing method of biomass type | mold molded fuel which can manufacture a molded fuel. The second object of the present invention is to provide a method for producing a biomass-based molded fuel capable of improving the substitution rate by biomass in coal-fired co-firing of a thermal power plant and reducing the generation of global warming gas. .

The invention which concerns on Claim 1 attaches the aqueous solution or suspension of slaked lime to the biomass raw material which consists of biomass powder or a biomass ground material, The process of heating the biomass raw material which this liquid adhered to 80-100 degreeC, And a method for producing a biomass-based molded fuel comprising a step of heating and molding the heated biomass raw material into a briquette or plate shape by applying a pressure of 100 to 500 MPa by a double roll press at a temperature of 80 to 100 ° C. is there. In the manufacturing method of the biomass type | mold molded fuel described in this Claim 1, the chemical action which mainly has the lignin and hemicellulose content in a biomass component by attaching a slaked lime suspension to the biomass raw material which is the main raw material first. To add plasticity to the biomass material. Although there is a solution such as NaOH or KOH as an alkali treatment liquid that can be expected to have such an action, even if plasticity is imparted thereby, the mechanical strength may be lowered due to the high hygroscopicity of the obtained molded fuel. Therefore, the present invention is limited to an aqueous solution or suspension of slaked lime [Ca (OH) ₂ ]. Next, this aqueous solution of slaked lime is heated to a temperature of 80 to 100 ° C. to further impart plasticity to the biomass material. Further, the heated biomass material is continuously formed into a briquette or the like by a high-pressure double roll press at a temperature of 80 to 100 ° C. to produce a biomass-based molded fuel. At this time, the fuel is molded with a high compressive force while giving a strong shearing force to the fibrous biomass raw material by a double roll press in the presence of steam, so the fibrous biomass raw materials are intertwined strongly and have a relatively high density. A molded fuel can be obtained.

  As shown in FIG. 1 and FIG. 2, the invention according to claim 2 includes a step of attaching an aqueous solution or suspension 13 of slaked lime to a biomass raw material 12 made of biomass powder or pulverized biomass, and the liquid 13 is attached. The step of mixing the biomass raw material 12 with the coal raw material 14 having a particle size of 3 mm or less at a ratio of 100% by mass or less with respect to 100% by mass of the biomass raw material and heating at a temperature of 80 to 100 ° C. It is a manufacturing method of biomass type | mold molded fuel including the process of applying the pressure of 100-500 Mpa by the double roll-type press 17 at the temperature of -100 degreeC, and heating and shape | molding in briquette shape or plate shape. In the method for producing a biomass-based molded fuel described in claim 2, first, a slaked lime suspension 13 is attached to a biomass raw material 12 which is a main raw material, so that a chemical mainly composed of lignin and hemicellulose in a biomass component. The plasticity is imparted to the biomass raw material 12 by the target action. Next, the biomass raw material 12 to which the aqueous solution or suspension 13 of the slaked lime is adhered is mixed with the coal raw material 14 at a predetermined ratio and heated at a temperature of 80 to 100 ° C. Gives plasticity. Furthermore, this mixture 16 is continuously molded into a briquette or plate shape by a high-pressure double roll press 17 at a temperature of 80 to 100 ° C. to produce a biomass-based molded fuel 11. At this time, the fuel 11 is molded with a high compressive force while applying a strong shearing force to the fibrous biomass raw material 12 by the double roll press 17 in the presence of steam, and the compressive force is increased by the presence of a relatively hard coal raw material. Since the fiber biomass raw material 12 is entangled strongly with each other because it is quickly transmitted to the inside of the fuel 11, heat is generated due to frictional resistance between the roll surface and the mixture 16 and frictional resistance between each particle of the mixture 16, and the temperature of the mixture 16. Is further increased, plasticity is further imparted to the biomass raw material 12 in the mixture 16, and the molded fuel 11 with less spring back and high density can be obtained. Thereby, since the coal raw material 14 can be pressure-bonded and integrated between the biomass raw materials 12 having a binder property, the biomass raw material 12 and the coal raw material 14 are isolated even if the biomass-based molded fuel 11 is pulverized. Is unlikely to occur. Further, the calorific value of the molded fuel 11 in which the coal raw material is added to the biomass raw material is higher than that of the molded fuel using only the biomass raw material.

Moreover, adhesion of the aqueous solution or suspension 13 of slaked lime to the biomass raw material 12 is obtained by mixing water with a mass of slaked lime corresponding to 30 × 10 ^{−3 to} 60 × 10 ⁻³ g per 1 kg of biomass dry mass. The aqueous solution or suspension 13 to be produced is preferably added to the biomass raw material 12. Here, the biomass dry mass refers to the mass when the biomass raw material 12 is completely dried. Furthermore, it is preferable that the biomass raw material 12 is a raw material obtained by pulverizing one or more industrial wastes selected from the group consisting of agricultural and forestry wastes, unused plants and plant fibers.

  The invention according to claim 5 is the invention according to claim 1, and further, as shown in FIG. 2, water vapor generated during the heating / mixing process is held in the mixture 16, and water vapor coexists during the heating / molding process. It is characterized in that after compressing force with shearing force is applied to the mixture 16 below, the compressing force is instantaneously released, thereby causing the dissipation of moisture in the mixture 16 and shrinkage of the molded product due to air cooling. To do. In the method for producing a biomass-based molded fuel according to claim 5, the water vapor generated from the mixture 16 during the heating / mixing step is retained in the mixture 16, and the coexistence of the water vapor during the heating / molding step of the mixture 16 is performed. When a compressive force with shear force is applied to the mixture under the double roll press 17, the water vapor is compressed into water, and when the pressure of the double roll press 17 is instantaneously released in this state, Compressed water dissipates instantaneously, and the molded product shrinks with rapid air cooling, so that it has mechanical strength that can withstand practical use, saves space by increasing bulk density, and generates heat by dehydration. An excellent biomass-based molded fuel 11 can be produced.

  According to the present invention, by attaching an aqueous solution of slaked lime to a biomass raw material made of biomass powder or the like, the biomass raw material is plasticized, and the biomass raw material to which this liquid is attached is heated to 80 to 100 ° C. By further imparting plasticity to the biomass material, the heated biomass material is heated and molded into a briquette or the like by applying a pressure of 100 to 500 MHz with a double roll press at a temperature of 80 to 100 ° C. The fuel is molded with high compressive force while giving a strong shearing force to the fibrous biomass raw material in the presence of coexistence. As a result, fibrous biomass raw materials are strongly entangled with each other, and a molded fuel having a relatively high density can be obtained. Further, a molded fuel having high mechanical strength can be produced without providing a conventional process of carbonizing biomass at a predetermined temperature or without adding a conventional binder. Furthermore, in the method of the present invention, in addition to briquette-shaped molded fuel, large and thin plate-shaped molded fuel can also be manufactured. By crushing and pulverizing these molded fuels, flaky fuel used in various boilers, thermal power Biomass-based molded fuel that can be used for multiple purposes, such as pulverized fuel used in power generation, can be manufactured.

  On the other hand, by attaching an aqueous solution of slaked lime to a biomass raw material made of biomass powder or the like, plasticity is imparted to the biomass raw material, and a coal raw material is mixed with the biomass raw material to which this liquid is adhered at a predetermined ratio and 80 to 100 ° C. By heating at a temperature of 100 ° C., plasticity is imparted to the biomass raw material, and the heated mixture is heated and molded into a briquette or the like by applying a pressure of 100 to 500 MPa by a double roll press at a temperature of 80 to 100 ° C. Therefore, the fuel is molded with a high compressive force while giving a strong shearing force to the fibrous biomass raw material in the presence of steam, and the compressive force is quickly transmitted to the inside of the fuel due to the presence of a relatively hard coal raw material. The As a result, fibrous biomass materials are strongly entangled with each other, and heat is generated due to frictional resistance between the roll surface and the mixture and frictional resistance between the particles of the mixture, and the temperature of the mixture further rises, and the biomass material in the mixture is plasticized. Therefore, coal raw materials can be pressure-bonded and integrated between biomass raw materials having binder properties, and a molded fuel with less springback and high density and heat generation can be obtained. Therefore, even if the biomass-based molded fuel is pulverized, it is difficult to isolate the biomass raw material and the coal raw material, so that it is possible to produce molded fuels of various shapes and sizes with high mechanical strength and good storage properties. In addition, it is possible to improve the substitution rate with biomass in coal-fired co-fired thermal power plants and reduce the generation of global warming gas.

  Furthermore, water vapor generated from the mixture during the heating / mixing step is retained in the mixture, and when the mixture is subjected to a compressive force with shear force by a double roll press in the presence of the water vapor during the heating / molding step of the mixture, When the water vapor is compressed into water, and the pressure of the double roll press is instantaneously released in this state, the compressed water is instantly dissipated and the molded product contracts with rapid air cooling. As a result, it is possible to produce a biomass-based molded fuel that has mechanical strength that can withstand practical use, is excellent in storage and transportability due to an increase in bulk density, and has an increased calorific value due to dehydration.

Next, the best mode for carrying out the present invention will be described with reference to the drawings.
<First Embodiment>
As shown in FIGS. 1 and 2, the method for producing the biomass-based molded fuel 11 mainly composed of the biomass raw material 12 includes a step of attaching an aqueous solution or suspension 13 of slaked lime to the biomass raw material 12, It includes a step of mixing and heating the coal raw material 14 to the biomass raw material 12 attached, and a step of heating and molding the mixture 16 into a predetermined shape by a double roll press 17 under heating. Biomass is one or more industrial wastes selected from the group consisting of agricultural and forestry wastes, unused plants and plant fibers. For example, wood waste such as sawdust, bark, bagasse (cane sugar cane), beet pulp, rice husk, rice straw, cottonseed oil cane, empty fruit bunch, as well as corrugated paper and construction waste . The empty fruit bunch is a residue obtained by removing the pulp containing fats and oils from palm fruit, which is a plant of the palm family, and is also called palm fruit bunch. Of these biomass, rice husks and empty fruit bunches are biomass that are extremely difficult to mold by known molding methods, and the present invention is a method for producing molded fuel relatively easily using these biomasses. If these biomass powders or pulverized products are used, the moisture content is naturally dried to 10 to 16% by mass, preferably 13 to 15% by mass, and the particle size is 3 mm or less, preferably 2 mm or less. If the particle size is larger than this without pulverization, the particle size is 3 mm or less, preferably 2 mm or less, or the diameter is 3 mm or less, preferably 2 mm or less and the diameter is 5 mm or less, preferably 2 mm or less. The biomass raw material 12 is produced by being pulverized into a fiber shape or a rod shape. Here, the moisture content of the biomass raw material 12 is limited to the range of 10 to 16% by mass, and if it is less than 10% by mass, it is difficult to achieve only by natural drying, and the drying cost increases. This is because if the slaked lime suspension is added, the amount of water becomes excessive due to the addition of the slaked lime suspension, and the calorific value of the fuel 11 decreases, and the mechanical strength of the molded fuel 11 becomes insufficient. Further, the biomass raw material 12 is limited to a granular material having a particle diameter of 3 mm or less or a fiber shape or a rod shape having a diameter and length of 3 mm or less and 5 mm or less, and the mechanical strength of the molded fuel 11 is insufficient outside these ranges. Because.

Attachment of the aqueous solution or suspension 13 of slaked lime to the biomass raw material 12 is 30 × 10 ^{−3 to} 60 × 10 ⁻³ g, preferably 30 × 10 ⁻³ to 40 × 10 ^{− with} respect to 1 kg of biomass dry mass. ^It is performed by adding an aqueous solution or suspension 13 obtained by mixing slaked lime having a mass corresponding to ³ g to water to the biomass raw material 12. Here, the biomass dry mass refers to the mass when the biomass raw material 12 is completely dried, that is, when the moisture content of the biomass raw material 12 is 0 mass%. Since the solubility of slaked lime in water is 0.16 g / 100 g (1.6 g / 1 liter) at 20 ° C., slaked lime below the solubility is dissolved in water to become ions, and slaked lime exceeding the solubility is dispersed in water. Composed. That is, when slaked lime having a solubility or lower is mixed with water, an aqueous solution of slaked lime is formed.When slaked lime exceeding the solubility is mixed with water, a portion of the slaked lime is dissolved in water and the remaining slaked lime is dispersed in water Suspension. Furthermore, the mass of slaked lime mixed with water to obtain the aqueous solution or suspension 13 of the slaked lime was limited to the range of 30 × 10 ^{−3 to} 60 × 10 ⁻³ g with respect to 1 kg of biomass dry mass. If the amount is less than 30 × 10 ⁻³ g, the biomass raw material 12 cannot be provided with sufficient plasticity in terms of the preparation of the aqueous solution or suspension 13 of slaked lime, and if it exceeds 60 × 10 ⁻³ g, it is involved in the plasticity of the biomass. This is because slaked lime that does not dissolve in water increases. As a method of bringing the slaked lime aqueous solution or suspension 13 into contact with the biomass raw material 12 and attaching the slaked lime suspension 13 to the entire surface of the biomass raw material 12, as shown in FIG. When the biomass raw material 12 classified by the first sieve 31 and having a predetermined thickness and length is placed on the belt conveyor 15 and conveyed, the biomass raw material 12 is sprayed with an aqueous solution or suspension 13 of slaked lime. The method of doing is mentioned. In this method, the slaked lime aqueous solution or suspension 13 can be attached to the entire surface of the biomass raw material 12 relatively efficiently. In this embodiment, the slaked lime aqueous solution or suspension is sprayed and adhered to the biomass raw material, but the biomass raw material is passed through the slaked lime aqueous solution or suspension, or the biomass raw material is passed through the slaked lime aqueous solution or suspension. You may boil in suspension.

On the other hand, the coal raw material 14 is dried to a surface moisture content of 3% by mass or less, preferably 1% by mass or less, and pulverized to a particle size of 1 mm or less, preferably 0.5 mm or less. Here, the moisture content on the surface of the coal raw material 14 is limited to 3% by mass or less, and if it exceeds 3% by mass, the coal raw material 14 adheres to an apparatus such as a double roll press 17 or the like due to excessive moisture and after molding. This is because the mechanical strength of the fuel 11 decreases. The reason why the particle size of the coal raw material 14 is limited to 1 mm or less is that if it exceeds 1 mm, the coal raw material 14 cannot be compressed and integrated between the biomass raw materials 12. As shown in FIG. 2, the coal raw material 14 pulverized by the second pulverizer 22 and classified by the second sieve 32 and having a predetermined particle size is supplied to the mixer 18. The mixing ratio of the coal raw material 14 to the biomass raw material 12 is 100% by mass or less, preferably 25 to 75% by mass of the coal raw material with respect to 100% by mass of the biomass raw material. The mixture 16 is supplied to a heater 20 and heated to a temperature of 80 to 100 ° C., preferably 90 to 100 ° C., and dried. Examples of the heater 20 include a flash dryer (airflow dryer), a fluidized bed dryer (horizontal type), and a drum dryer (drum type dryer). Further, this heating is preferably performed by blowing a gas having a small amount of O ₂ from a heating gas generation furnace (not shown), and the mixture 16 is simultaneously dried by this heating. Although most of the gas supplied by this heating is circulated, some excess of the gas is discharged. Further, the gas is circulated in a safe atmosphere containing a large amount of water vapor and a small amount of O ₂ . Here, the mixing ratio of the coal raw material 14 with respect to the biomass raw material 12 is limited to 100% by mass or less, and if it exceeds 100% by mass, it cannot be regarded as the biomass-based molded fuel 11 mainly composed of the biomass raw material 12, but a thermal power plant. This is because the rate of replacement with biomass cannot be improved in co-fired coal-fired power. Further, the heating temperature at the time of mixing the mixture 16 is limited to the range of 80 to 100 ° C. The reason is that if the temperature is less than 80 ° C., a sufficient amount of water vapor is not retained in the biomass raw material 12. This is because it is necessary to increase the pressure to atmospheric pressure or higher.

  The heated mixture 16 is stored in the molding hopper 19 while being kept at a temperature of 80 to 100 ° C., preferably 90 to 100 ° C. Although it is better that the moisture content of the mixture 16 is small at this time, in practice, it becomes equilibrium moisture in the transportation process and storage process of the molded fuel, so that it is 10 to 18% by mass, preferably about 10 to 15% by mass. It is economical to mold with. The mixture 16 in the molding hopper 19 is pumped between a pair of rolls 17 a and 17 b of a double roll press 17 disposed below the molding hopper 19 by a screw feeder (not shown) in the hopper 19. It is heated and molded into a briquette or plate shape under a pressure of 100 to 500 MPa, preferably 300 to 400 MPa. Here, the mixture 16 is limited to a temperature range of 80 to 100 ° C. The reason why the sufficient amount of water vapor is not retained in the biomass raw material 12 is less than 80 ° C., and the pressure exceeds the atmospheric pressure when the temperature exceeds 100 ° C. This is because it is necessary to increase the pressure. Further, the molding pressure of the mixture 16 by the double roll press 17 is limited to the range of 100 to 500 MPa because the molding fuel 11 having a predetermined mechanical strength cannot be obtained when the pressure is less than 100 MPa, and more than necessary when the pressure exceeds 500 MPa. This is because energy is consumed. In this embodiment, the mixture is formed into a briquette shape, but a pair of rolls without a recess for forming a briquette shape, that is, a double roll type having a pair of rolls with a smooth outer peripheral surface. You may shape | mold continuously into a thin plate shape with a press. Specifically, this will be described in a second embodiment described later.

  The screw feeder is driven by a feeder motor 24 and is configured to pump the mixture 16 in the molding hopper 19 below the molding hopper 19. The pair of rolls 17a and 17b are supported by a pair of rotating shafts 17c and 17d, respectively. One rotating shaft 17c is a driven shaft that rotatably supports one roll 17a, and is pressed against the other rotating shaft 17d with a predetermined pressure by a hydraulic cylinder (not shown). The other rotary shaft 17d is a drive shaft that is rotatably supported by a bearing (not shown) and is driven by a roll motor (not shown), and the other roll 17b is fixed to the other rotary shaft 17d. . A large number of recesses 17e and 17f are formed in alignment on the outer peripheral surfaces of the pair of rolls 17a and 17b, respectively, and the outer peripheral surfaces of these rolls 17a and 17b are in pressure contact with each other to rotate in opposite directions. The mixture 16 pumped by the screw feeder 23 is compression-molded to form the briquette-shaped molded fuel 11. In addition, after cooling the briquette-shaped molded fuel 11 to room temperature by air cooling or the like, the cooled briquette-shaped molded fuel 11 is subjected to a screening process (classification process) so that the size of the fuel 11 is made uniform. In this embodiment, one rotary shaft is a driven shaft and the other rotary shaft is a drive shaft. However, the pair of rotary shafts may be drive shafts driven by separate roll motors. .

  One end of a deaeration pipe 27 is connected to the upper end of the molding hopper 19, the other end of the deaeration pipe 27 is connected to the suction port of the deaeration blower 28, and its discharge port is opened to the atmosphere. The deaeration pipe 27 is provided with a dust collector 29, and is configured so that the mixture 16 floating in the dust collector 29 is collected. Further, a belt conveyor 33 is provided so that one end is positioned below the pair of rolls 17a and 17b, and a box-shaped powder separator 34 whose opening is covered with a net 34a is provided at the other end of the belt conveyor 33. The mesh 34a has an opening smaller than the diameter of the molded fuel 11. The mixture 16 stored in the powder separator 34 is configured to be returned to the mixer 18 by a transporter 37 through a transport path 36. Reference numerals 38 and 39 in FIG. 2 denote hoods for collecting the floating mixture 16, and these hoods 38 and 39 are connected to the deaeration pipe 27 through the first and second branch pipes 41 and 42. Reference numerals 43 to 45 in FIG. 2 are dampers provided for adjusting the flow rates of air passing through the deaeration pipe 27, the first branch pipe, and the second branch pipe, respectively. 2 is a heater provided on the outer peripheral surface of the molding hopper 19 to heat the mixture 16 in the hopper 19 to a predetermined temperature.

  In the method for producing the biomass-based molded fuel 11 configured as described above, since the slaked lime suspension 13 is first attached to the biomass raw material 12 which is the main raw material, the chemical mainly composed of lignin and hemicellulose in the biomass component. The plasticity is imparted to the biomass raw material 12 by the action. Next, after mixing the coal raw material 14 with the biomass raw material 12 by the mixer 18, the biomass raw material 12 is further plasticized by heating the biomass raw material 12 by heating to a temperature of 80 to 100 ° C. with the heater 20. Make it easy to deform. Further, the biomass-based molded fuel 11 is manufactured by continuously molding the mixture 16 into a briquette or plate shape with a high-pressure double roll press 17 at a temperature of 80 to 100 ° C. At this time, water vapor generated during the heating / mixing step is held in the mixture 16, and the mixture 16 is pushed between the pair of rolls 17a and 17a by the screw feeder 23 in the presence of water vapor during the heating / molding step of the mixture 16, When a compressive force accompanied by a shearing force is applied, the water vapor is compressed into water, and the pair of rolls 17a and 17b whose inside is kept at a high pressure in this state are separated, and the pressure of the double roll press 17 is instantaneously increased. When released, the compressed water dissipates instantly and the molded product shrinks with rapid air cooling.

In other words, since the fuel 11 is molded with a high compressive force while being applied to the fibrous biomass material 12 with a strong shearing force by the double roll press 17 in the presence of steam, the fibrous biomass materials 12 are strongly entangled with each other. , Heat is generated by the friction resistance between the surfaces of the rolls 17a and 17b and the mixture 16 and the friction resistance between the particles of the mixture 16, the temperature of the mixture 16 is further increased, and the biomass raw material 12 is further plasticized, and the spring back is generated. A small and high density molded fuel 11 can be obtained. More specifically, when the particulate mixture 16 is compression-molded, the mixture is supplied between the pair of rolls 17a and 17b while the particles approach each other and come into close contact with each other while releasing the gas between the particles of the mixture 16. Since the space between the 16 particles is compressed with a large amount of water vapor, the water vapor is condensed when compressed between the pair of rolls 17a and 17b, and the gas volume between the particles is rapidly reduced. Since the particles are compressed in close contact with each other, the process of releasing the gas between the particles is reduced, the compression speed of the pair of rolls 17a and 17b can be increased, and the productivity of the molded fuel 11 can be increased. It can be improved. Since the molded fuel 11 molded between the pair of rolls 17a and 17b is under atmospheric pressure when discharged from the pair of rolls 17a and 17b, the water inside the molded fuel 11 evaporates from the surface of the molded fuel 11. Thus, the moisture of the molded fuel 11 is further reduced. When the fibrous biomass raw material 12 is compressed, the biomass raw material 12 is mixed with a harder coal raw material 14 having a calorific value higher than that of the biomass raw material 12 although the compressibility of the compressive force is low in the deep part of the raw material 12. Thus, it is possible to improve the transmission of compressive force to the inside of the molded fuel 11, and to obtain a molded fuel 11 which is harder and has a high calorific value by increasing the density. The moisture content of the molded fuel 11 decreases to 5 to 7% by mass, and the bulk density increases to 1.1 to 1.2 g / cm ³ . As a result, since the coal raw material 14 is pressure-bonded and integrated between the biomass raw materials 12 having binder properties that are easily deformed and easily formed, the biomass raw material can be obtained even if the molded fuel 11 is pulverized. 12 and the coal raw material 14 are hardly isolated. Therefore, the molded fuel 11 having various shapes and sizes with high mechanical strength and good storage properties can be produced.

  If coal and biomass are co-fired at the same time, the combustion efficiency will increase, or the nitrogen content in the biomass will be less than the nitrogen content in the coal, so the concentration of NOx in the exhaust gas can be reduced and the combustion of coal alone It is also possible to reduce the thermal synthesis NOx produced in the process. Further, by achieving high speed rotation when the molded fuel 11 is molded by the double roll press 17, the mass productivity of the molded fuel 11 can be improved and the manufacturing cost can be reduced. Further, by crushing and pulverizing the briquette-shaped molded fuel 11, it is possible to produce a biomass-based molded fuel 11 corresponding to a multipurpose application such as a flaky fuel used for various boilers and a fine powder fuel used for thermal power generation. As a result, the combustibility of the pulverized coal can be improved by co-firing the pulverized biomass-based molded fuel 11, and the efficiency can be increased during low-load combustion.

<Second Embodiment>
FIG. 3 shows a second embodiment of the present invention. In this embodiment, the heated mixture is kept at a temperature of 80 to 100 ° C., preferably 90 to 100 ° C., and a pressure of 100 to 500 MPa, preferably 300 to 500 MPa by a high-pressure double roll press. Is heated and molded into a large and thin plate shape (for example, width 100 cm, thickness 0.5 to 1.0 cm, length 30 to 250 cm, bulk density 1.1 to 1.2 g / cm ³ ). . The configuration other than the above is the same as that of the first embodiment. In the method for producing a biomass-based molded fuel configured in this way, the biomass-based molded fuel is molded into a large and thin plate, so that it becomes a molded fuel with excellent storability. The plate-shaped molded fuel is cooled to room temperature by air cooling or the like, and then crushed and pulverized. Further, the crushed and pulverized molded fuel is subjected to a screening process (classification process) to obtain a flaked molded fuel. This can reduce the transportation cost of the molded fuel. This flaky shaped fuel is transported to a thermal power plant and further pulverized to be used as fuel. Even if the molded fuel is pulverized in this way, the coal raw material is compressed and integrated between the biomass raw materials having binder properties at the time of pressurization and molding. Isolation of raw materials hardly occurs. Accordingly, it is possible to improve the substitution rate by biomass in the coal-fired co-firing of the thermal power plant to 10 to 20% and reduce the generation of global warming gas. Since the operation other than the above is substantially the same as the operation of the first embodiment, repeated description will be omitted.

  In the first and second embodiments, the coal raw material is mixed with the biomass raw material, but the molded fuel may be manufactured using only the biomass raw material without mixing the coal raw material. In this case, after attaching an aqueous solution or suspension of slaked lime to the biomass raw material, the biomass raw material to which this liquid is attached is heated to 80 to 100 ° C., preferably 90 to 100 ° C. with a heater, and further dried. The heated biomass raw material 12 is heated and molded into a briquette or plate shape by applying a pressure of 100 to 500 MPa, preferably 300 to 400 MPa by a double roll press at a temperature of 80 to 100 ° C., preferably 90 to 100 ° C. . In the molded fuel composed only of the biomass raw material, the moldability and the calorific value are lower than those of the molded fuels of the first and second embodiments, but the replacement rate from coal to biomass is increased, and the global warming gas Generation can be further reduced.

Next, examples of the present invention will be described in detail together with comparative examples.
<Example 1>
First, rice straw was naturally dried to a moisture content of 15% by mass, and then pulverized by a pulverizer to obtain a biomass material having a particle size of 2.0 mm or less. Further, an aqueous solution or suspension of slaked lime having a concentration of 1.6 g / liter (in this case, all slaked lime is dissolved in water to form a slaked lime aqueous solution, hereinafter referred to as a slaked lime aqueous solution) was prepared. Next, after putting the said biomass raw material in the slaked lime aqueous solution and boiling for 3 hours, it took out from the slaked lime aqueous solution and dried until the moisture content became 15 mass%. Further, 3.0 g of this biomass raw material was subjected to a pressure of 240 MPa at a temperature of 90 ° C., and a tablet type (tablet type) briquette shaped fuel 71 having a diameter of 25 mm was molded by the cylindrical mold 70 of FIG. Left at room temperature for 24 hours. This molded fuel 71 was referred to as Example 1. The moisture content of the molded fuel 71 was 6.9% by mass, and the bulk density was 1.20 g / cm ³ .
<Example 2>
A tablet-shaped molded fuel was obtained in the same manner as in Example 1 except that fir shell was used instead of rice straw. This molded fuel was designated as Example 2. The moisture content of the molded fuel was 7.2% by mass, and the bulk density was 1.14 g / cm ³ .

<Example 3>
First, rice straw was naturally dried to a moisture content of 15% by mass, and then pulverized by a pulverizer to obtain a biomass material having a particle size of 2.0 mm or less. A slaked lime aqueous solution having a concentration of 1.6 g / liter was prepared. Subsequently, after putting the said biomass raw material in the slaked lime aqueous solution and boiling for 3 hours, it took out from the slaked lime aqueous solution and dried until the moisture content became 15 mass%. On the other hand, after drying coal and making the moisture content into 11 mass%, it grind | pulverized with the grinder and obtained the coal raw material which made the particle size 1.0mm or less. Next, the biomass raw material and the coal raw material were mixed at a blending ratio of 70% by mass to 30% by mass while being maintained at 90 ° C. Further, 3.0 g of this mixture was subjected to a pressure of 240 MPa at a temperature of 90 ° C. to form a tablet-type (tablet-type) briquette shaped fuel having a diameter of 25 mm, and then allowed to stand at room temperature for 24 hours. This molded fuel was designated as Example 3. The moisture content of the molded fuel was 4.4% by mass, and the bulk density was 1.17 g / cm ³ .
<Example 4>
A tablet-shaped molded fuel was obtained in the same manner as in Example 3 except that fir shell was used instead of rice straw. This molded fuel was designated as Example 4. The moisture content of the molded fuel was 5.6% by mass, and the bulk density was 1.14 g / cm ³ .

<Comparative Example 1>
First, rice straw was naturally dried to a moisture content of 15% by mass, and then pulverized by a pulverizer to obtain a biomass material having a particle size of 2.0 mm or less. Next, 3.0 g of this biomass material was subjected to a pressure of 240 MPa at room temperature to form a tablet-type (tablet-type) briquette shaped fuel having a diameter of 25 mm, and then allowed to stand at room temperature for 24 hours. This molded fuel was referred to as Comparative Example 1. The moisture content of the molded fuel was almost unchanged at 15% by mass, and the bulk density was 0.97 g / cm ³ .
<Comparative example 2>
A tablet-shaped molded fuel was obtained in the same manner as in Comparative Example 1 except that fir shell was used instead of rice straw. This molded fuel was referred to as Comparative Example 2. The moisture content of the molded fuel was almost unchanged at 15% by mass, and the bulk density was 1.00 g / cm ³ .

<Comparative Example 3>
First, rice straw was naturally dried to a moisture content of 15% by mass, and then pulverized by a pulverizer to obtain a biomass material having a particle size of 2.0 mm or less. Moreover, after drying coal and making the moisture content into 11 mass%, it grind | pulverized with the grinder and obtained the coal raw material which made the particle size 1.0mm or less. Next, the biomass raw material and the coal raw material were mixed at a blending ratio of 70% by mass to 30% by mass while being kept at room temperature. Further, 3.0 g of this mixture was subjected to a pressure of 240 MPa at room temperature to form a tablet-type (tablet-type) briquette shaped fuel having a diameter of 25 mm, and then allowed to stand at room temperature for 24 hours. This molded fuel was referred to as Comparative Example 3. The moisture content of the molded fuel was almost unchanged at 13.8% by mass, and the bulk density was 1.06 g / cm ³ .
<Comparative example 4>
A tablet-shaped molded fuel was obtained in the same manner as in Comparative Example 3 except that fir shell was used instead of rice straw. This molded fuel was referred to as Comparative Example 4. The moisture content of the molded fuel was almost unchanged at 13.8% by mass, and the bulk density was 1.03 g / cm ³ .

<Comparative Example 5>
First, rice straw was naturally dried to a moisture content of 15% by mass, and then pulverized by a pulverizer to obtain a biomass material having a particle size of 2.0 mm or less. A slaked lime aqueous solution having a concentration of 1.6 g / liter was prepared. Next, after putting the said biomass raw material in the slaked lime aqueous solution and boiling for 3 hours, it took out from the slaked lime aqueous solution and dried until the moisture content became 15 mass%. Further, 3.0 g of this biomass raw material was subjected to a pressure of 240 MPa at room temperature to form a tablet-type (tablet-type) briquette shaped fuel having a diameter of 25 mm, and then allowed to stand at room temperature for 24 hours. This molded fuel was designated as Comparative Example 5. The moisture content of the molded fuel was almost unchanged at 15% by mass, and the bulk density was 0.98 g / cm ³ .
<Comparative Example 6>
A tablet-shaped molded fuel was obtained in the same manner as in Comparative Example 5 except that fir shell was used instead of rice straw. This molded fuel was designated as Comparative Example 6. The moisture content of the molded fuel was almost unchanged at 15% by mass, and the bulk density was 1.00 g / cm ³ .

<Comparative Example 7>
First, rice straw was naturally dried to a moisture content of 15% by mass, and then pulverized by a pulverizer to obtain a biomass material having a particle size of 2.0 mm or less. A slaked lime aqueous solution having a concentration of 1.6 g / liter was prepared. Subsequently, after putting the said biomass raw material in the slaked lime aqueous solution and boiling for 3 hours, it took out from the slaked lime aqueous solution and dried until the moisture content became 15 mass%. On the other hand, after drying coal and making the moisture content into 11 mass%, it grind | pulverized with the grinder and obtained the coal raw material which made the particle size 1.0mm or less. Next, the biomass raw material and the coal raw material were mixed at a blending ratio of 70% by mass to 30% by mass while being kept at room temperature. Further, 3.0 g of this mixture was subjected to a pressure of 240 MPa at room temperature to form a tablet-type (tablet-type) briquette shaped fuel having a diameter of 25 mm, and then allowed to stand at room temperature for 24 hours. This molded fuel was designated as Comparative Example 7. The moisture content of the molded fuel was almost unchanged at 13.8% by mass, and the bulk density was 1.06 g / cm ³ .
<Comparative Example 8>
A tablet-shaped molded fuel was obtained in the same manner as in Comparative Example 7, except that fir shell was used instead of rice straw. This molded fuel was designated as Comparative Example 8. The moisture content of the molded fuel was almost unchanged at 13.8% by mass, and the bulk density was 1.03 g / cm ³ .

<Comparative Example 9>
First, rice straw was naturally dried to a moisture content of 15% by mass, and then pulverized by a pulverizer to obtain a biomass material having a particle size of 2.0 mm or less. Next, 3.0 g of this biomass material was subjected to a pressure of 240 MPa at a temperature of 90 ° C. to form a tablet-type (tablet-type) briquette-shaped molded fuel having a diameter of 25 mm, and then allowed to stand at room temperature for 24 hours. This molded fuel was designated as Comparative Example 9. The moisture content of the molded fuel was 7.1% by mass, and the bulk density was 1.10 g / cm ³ .
<Comparative Example 10>
A tablet-shaped molded fuel was obtained in the same manner as in Comparative Example 9, except that fir shell was used instead of rice straw. This molded fuel was designated as Comparative Example 10. The moisture content of the molded fuel was 7.5% by mass, and the bulk density was 1.09 g / cm ³ .

<Comparative Example 11>
First, rice straw was naturally dried to a moisture content of 15% by mass, and then pulverized by a pulverizer to obtain a biomass material having a particle size of 2.0 mm or less. Moreover, after drying coal and making the moisture content into 11 mass%, it grind | pulverized with the grinder and obtained the coal raw material which made the particle size 1.0mm or less. Next, the biomass raw material and the coal raw material were mixed at a blending ratio of 70% by mass to 30% by mass while being maintained at 90 ° C. Further, 3.0 g of this mixture was subjected to a pressure of 240 MPa at a temperature of 90 ° C. to form a tablet-type (tablet-type) briquette shaped fuel having a diameter of 25 mm, and then allowed to stand at room temperature for 24 hours. This molded fuel was designated as Comparative Example 11. The moisture content of the molded fuel was 4.9% by mass, and the bulk density was 1.10 g / cm ³ .
<Comparative Example 12>
A tablet-shaped molded fuel was obtained in the same manner as in Comparative Example 11 except that fir shell was used instead of rice straw. This molded fuel was designated as Comparative Example 11. The moisture content of the molded fuel was 5.8% by mass, and the bulk density was 1.13 g / cm ³ .

<Comparative test 1 and evaluation>
As for the breaking strength of the tablet-type (tablet-type) briquette shaped molded fuel 71 of Examples 1 to 4 and Comparative Examples 1 to 12, a compressive force is applied to the outer peripheral surface of the molded fuel 71 as shown in FIG. It was measured. The result is shown in FIG. As is clear from FIG. 6, the molded fuels of Comparative Examples 1 to 4 molded at room temperature without contacting the biomass raw material with the slaked lime aqueous solution had a low fracture strength of 7 to 23 kg, and the biomass raw material was contacted with the slaked lime aqueous solution. However, in the molded fuels of Comparative Examples 5 to 8 molded at room temperature, the fracture strength slightly improved to 16 to 25 kg, and Comparative Examples 9 to 9 molded at a temperature of 90 ° C. without contacting the biomass raw material with the slaked lime aqueous solution. With the 12 molded fuel, the fracture strength improved to some extent with 24 to 30 kg. However, the fracture strength of the molded fuel of Examples 1 to 4 with the slaked lime aqueous solution brought into contact with the biomass raw material and molded at a temperature of 90 ° C. was 32 to 30 kg. It turned out that it improved synergistically with 45 kg.

It is a block diagram which shows the manufacture procedure of the biomass type | mold molded fuel of 1st Embodiment of this invention. It is a block diagram which shows the manufacturing procedure of the biomass type | mold molded fuel. It is a block diagram which shows the manufacturing procedure of the biomass type | mold molded fuel of 2nd Embodiment of this invention. It is a section lineblock diagram showing the state where tablet-shaped molding fuel is compression-molded. It is a section lineblock diagram showing the state where tablet-like molded fuel was equipped in a tablet testing machine. It is a figure which shows the difference in the fracture strength by the molding conditions of the tablet of Examples 1-4 and Comparative Examples 1-12.

Explanation of symbols

11,71 Biomass shaped fuel 12 Biomass raw material 13 Slaked lime aqueous solution or suspension 14 Coal raw material 16 Mixture 17 Double roll press

Claims (5)

A step of attaching an aqueous solution or suspension of slaked lime to a biomass raw material made of biomass powder or pulverized biomass; and
Heating the biomass material to which the liquid is adhered to 80 to 100 ° C .;
And heating and molding the heated biomass raw material into a briquette or plate shape by applying a pressure of 100 to 500 MPa by a double roll press at a temperature of 80 to 100 ° C. Attaching an aqueous solution or suspension (13) of slaked lime to a biomass raw material (12) made of biomass powder or pulverized biomass; and
A coal raw material (14) having a particle size of 3 mm or less is mixed with the biomass raw material (12) to which the liquid (13) is adhered in a proportion of 100% by mass or less with respect to 100% by mass of the biomass raw material, and a temperature of 80 to 100 ° C. Heating with
And heating and molding the heated mixture (16) into a briquette or plate shape by applying a pressure of 100 to 500 MPa by a double roll press (17) at a temperature of 80 to 100 ° C. Manufacturing method. The adhesion of the aqueous solution or suspension (13) of slaked lime to the biomass raw material (12) is mixed with water with a mass of slaked lime corresponding to 30 × 10 ^{−3 to} 60 × 10 ⁻³ g per 1 kg of biomass dry mass. The method for producing a biomass-based molded fuel according to claim 1 or 2, which is carried out by adding an aqueous solution or suspension (13) obtained in this way to the biomass raw material (12).   The biomass raw material (12) is a raw material obtained by pulverizing one or more industrial wastes selected from the group consisting of agricultural and forestry wastes, unused plants and plant fibers. The manufacturing method of the biomass type | mold molded fuel of description.   Water vapor generated during the heating / mixing step is retained in the mixture (16), and the compressive force is applied to the mixture (16) under the coexistence of the water vapor during the heating / molding step after applying a compressive force with a shearing force. The method for producing a biomass-based molded fuel according to claim 1, wherein the molded product shrinks due to the dissipation of moisture in the mixture (16) and air cooling by being released instantaneously.

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