Method for manufacturing granules and apparatus for manufacturing granules, and method for melting a material to be melted using granules.

Abstract

The goal is to enable the conversion of waste plastics into fuel without requiring a large energy input, and to make waste plastics into a fuel with good flammability. [Solution] In manufacturing granules formed from plastic-containing waste, a compressed waste body is produced by compressing the waste, and granules with a lower particle size than the waste before compression are obtained by crushing this compressed body. The granule manufacturing apparatus includes a compressed waste body manufacturing apparatus 51 for producing a compressed waste body by compressing plastic-containing waste 3, and a crushing apparatus 52 for producing granules with a lower particle size than the waste before compression by crushing the compressed body produced by the compressed waste body manufacturing apparatus 51.

Description

Technical Field

[0001] The present invention relates to a method and apparatus for manufacturing granulated bodies, and a method for melting a molten material using the granulated bodies.

Background Art

[0002] As waste plastics, there are recycling residues discharged from the recycling processes of automobiles, electrical appliances, electrical and electronic parts, buildings, etc. Examples of uses for waste plastics such as such recycling residues include fuels used in melting furnaces and the like. For use as a fuel in a melting furnace or the like, it is known, for example, in Patent Document 1 to solidify waste plastics into pellets.

[0003] The technique described in Patent Document 1 uses a screw that compresses while sending plastic waste to a discharge section inside a casing, discharges the compacted and solidified plastic waste from the discharge section, and cuts the discharged compacted plastic waste with a cutting device to make it into pellets.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, compacting and solidifying plastic waste into pellets requires a considerable amount of energy. Moreover, cutting the compacted waste plastic also requires a significant amount of energy. Furthermore, if the waste plastic becomes too compacted during the compaction process, it takes a long time to burn when used as fuel in a melting furnace, resulting in inefficiency. In addition, if plastic waste with a low bulk density, such as packaging, is put into a melting furnace without compaction, it will be scattered by the gas flow of combustion air, making it impossible to use effectively as fuel.

[0006] Therefore, the present invention aims to enable the conversion of waste plastics into fuel without requiring a large energy input, and to enable the waste plastics to be used as a fuel with good combustibility. [Means for solving the problem]

[0007] To achieve this objective, the present invention provides a method for producing granulated materials. When manufacturing granules formed from plastic-containing waste, A compressed waste body is produced by compressing the aforementioned waste. The method is characterized by obtaining a granulated material with a lower particle size than the waste material before compression by crushing the compressed material.

[0008] In this method, plastic-containing waste only needs to be compressed to a degree that it can be crushed, and does not need to be compacted as it would be when pelletized by cutting, thus eliminating the need for the pressure and thermal energy required for compaction. Furthermore, after compression, the plastic-containing waste is crushed to form granules with a lower particle size than the waste before compression. These granules are not compacted, and their bulk density is increased, resulting in good combustibility.

[0009] According to the method for producing granules of the present invention, When manufacturing compressed waste, the waste is transported and compressed by a screw placed inside the casing. The compressed waste is discharged from an opening in the casing located downstream of the waste transport direction by the screw. When crushing the compressed material being discharged, it is preferable to crush it using a crushing device that is installed in a space in front of the opening in the direction of waste transport by the screw.

[0010] In this manner, the plastic-containing waste is preferably compressed by the screw and preferably crushed by the crushing device.

[0011] In the method for producing granulated material of the present invention, it is preferable to use a rotary crushing arm as the crushing device.

[0012] In this way, plastic-containing waste is preferably crushed.

[0013] According to the method for producing granules of the present invention, It is preferable that the distance between the opening and the crushing arm be 0.05 times or more and 0.2 times or less the diameter of the opening.

[0014] In this way, plastic-containing waste is crushed under favorable conditions.

[0015] The granular material manufacturing apparatus of the present invention is A compression manufacturing apparatus for producing compressed waste by compressing plastic-containing waste, The device is characterized by having a crushing device for crushing the compressed body produced by the aforementioned compressed body manufacturing device in order to produce a granulated body with a lower particle size than the waste before compression.

[0016] With such a configuration, it suffices that waste containing plastic is compression-molded by the compression body manufacturing device to such an extent that it can be crushed. Therefore, since there is no need to be compacted as in the case of pelletization by cutting, it does not require the pressure and thermal energy required for compaction. Further, the waste containing plastic is crushed by the crushing device after compression, and thus becomes a granulated body having a lower particle size than the waste before compression. This granulated body is not solidified and thus has good combustibility.

[0017] According to the manufacturing device of the granulated body of the present invention, The compression body manufacturing device has a casing, and a screw that is disposed inside the casing and compresses the waste while conveying it inside the casing, and an opening provided in the casing at a downstream position along the conveyance direction of the waste by the screw for discharging the compressed body of the waste from the casing. The crushing device is preferably provided with a space separated in front of the opening along the conveyance direction of the waste by the screw.

[0018] With such a configuration, the waste containing plastic is preferably compressed by the screw of the compression body manufacturing device and preferably crushed by the crushing device.

[0019] According to the manufacturing device of the granulated body of the present invention, it is preferable that the crushing device is a rotary crushing arm.

[0020] With such a configuration, the waste containing plastic is preferably crushed.

[0021] According to the manufacturing device of the granulated body of the present invention, it is preferable that the distance between the opening and the arm is 0.05 times or more and 0.2 times or less the diameter of the opening.

[0022] With such a configuration, waste containing plastic is crushed under favorable conditions.

[0023] The method for melting treatment of the melt object of the present invention is a method for melting a melt object using a granulated body formed from waste containing plastic as fuel, manufacturing a compressed body of waste by compressing the waste, manufacturing a granulated body having a lower particle size than the waste before compression by crushing the compressed body, feeding the granulated body having a lower particle size than the waste before compression together with the melt object into a melting furnace, characterized in that the granulated body fed into the melting furnace is burned to set the inside of the furnace to a predetermined melting temperature and melt the melt object.

[0024] In this way, for waste containing plastic, it is sufficient if it is compressed to such an extent that it can be crushed, and there is no need to be compacted as in the case of pelletization by cutting, so it does not require the pressure and thermal energy required for compaction. Also, waste containing plastic is crushed after compression and made into a granulated body having a lower particle size than the waste before compression. Therefore, this granulated body is not solidified and its bulk specific gravity has increased, so its combustibility is good. Therefore, the granulated body formed from waste containing plastic can be suitably used as fuel, and the melt object can be suitably melted.

[0025] According to the method for melting treatment of the melt object of the present invention, when manufacturing a compressed body of waste, the waste is compressed while being conveyed by a screw disposed inside a casing, the compressed body of waste is discharged from an opening provided in the casing at a downstream position along the conveyance direction of the waste by the screw, when crushing the discharged compressed body, it is crushed by a crushing device provided with a space separated in front of the opening along the conveyance direction of the waste by the screw, as the crushing device, a rotary crushing arm is used, It is preferable that the distance between the opening and the crushing arm be 0.05 times or more and 0.2 times or less the diameter of the opening.

[0026] In this way, plastic-containing waste is crushed under favorable conditions and used as fuel, allowing the material to be melted to be effectively treated. [Effects of the Invention]

[0027] According to the present invention, waste plastics can be converted into fuel without requiring a large amount of energy input, and moreover, waste plastics can be used as a fuel with good combustibility. [Brief explanation of the drawing]

[0028] [Figure 1] This figure shows a granular material manufacturing apparatus according to an embodiment of the present invention. [Figure 2] This figure shows the configuration of the crushing arm in the crushing device shown in Figure 1. [Figure 3] This figure shows the plastic-containing waste before fuel treatment in Example 2. [Figure 4] This figure shows the granular material obtained in Example 2. [Modes for carrying out the invention]

[0029] As shown in Figure 1, the granulation production apparatus of the embodiment of the present invention comprises a compressed body production apparatus 51 and a crushing apparatus 52.

[0030] The compressed body manufacturing apparatus 51 compresses and discharges plastic waste (an example of waste containing plastic) 3 that is put into the casing 2 using a horizontally positioned screw 4. In other words, the compressed body manufacturing apparatus 51 has a casing 2, an input section 7 into which the plastic waste 3 is put into the casing 2, an output section 8 that discharges the compressed plastic waste 3 from inside the casing 2, and a rotary screw 4 that compresses the plastic waste 3 that is put into the casing 2 from the input section 7 while sending it toward the output section 8.

[0031] The discharge section 8 has a discharge port 19 provided in the casing 2 and a discharge nozzle 20 that communicates with the discharge port 19.

[0032] The screw 4 has a rotating shaft 23 that passes horizontally through the casing 2 and helical screw blades 24 provided on the outer circumference of the rotating shaft 23. The casing 25 is equipped with an electric motor 25 that rotates the rotating shaft 23. The pitch of the screw blades 24 may be constant, or it may decrease towards the discharge section 8 side, i.e., the downstream side. This is done to compress the plastic waste 3.

[0033] Although not shown in the diagram, the inner surface of the casing 2 may be provided with multiple protrusions to prevent the plastic waste 3 from rotating together with the screw 4.

[0034] The casing 2 may be configured to heat the plastic waste 3 introduced into the casing 2, for example, by providing a heater in the faceplate 18 corresponding to the downstream end of the screw 4. However, it is preferable not to use a heater because if the plastic waste 3 melts inside the compressed body manufacturing apparatus 51, the compressed body will not be crushed.

[0035] The tip portion 53 of the rotating shaft 23 penetrates the casing 2 and protrudes outward from the casing 2. The tip 54 of the rotating shaft 23 is further from the casing than the tip of the discharge nozzle 20, and the crushing device 52 is constructed by providing a crushing arm 55 at this tip 54 of the rotating shaft 23. That is, the crushing arm 55 of the crushing device 52 is provided in front of the opening 56 in the direction of waste transport by the screw 4, separated by space. The crushing arm 55 is rotatable integrally with the rotating shaft 23 in the vertical plane.

[0036] An opening 56 is formed at the tip of the discharge nozzle 20, and when the crushing arm 55 rotates integrally with the rotating shaft 23, it passes a position located at a horizontal distance 57 from the opening 56, which has a predetermined diameter 58.

[0037] As shown in Figure 2, the crushing arms 55 are arranged evenly along the circumferential direction of the rotation axis 23. Each crushing arm 55 has its base end 59 attached to the rotation axis 23, and its tip 60 is a free end. In other words, each crushing arm 55 is arranged radially with respect to the rotation axis 23. Each crushing arm 55 is plate-shaped and, when viewed in the thickness direction, i.e., in the axial direction of the rotation axis 23, has a curved shape, for example, as shown in the figure. Note that the shape of the crushing arm 55 when viewed in the thickness direction can be a straight line or other appropriate shape instead of the above-mentioned arc shape. Each crushing arm 55 has a predetermined width and, as a result, has an inner circumferential arc 61 and an outer circumferential arc 62. As shown by arrow 63, the crushing arm 55 is configured to rotate with the rotation axis 23 in the direction from the outer circumferential arc 62 toward the inner circumferential arc 61.

[0038] The surface 64 of the plate-shaped crushing arm 55 that faces the opening 56 of the discharge nozzle 20 is flat. However, protrusions or the like may be formed on the surface 64 of the crushing arm 55 to promote crushing when it comes into contact with the compressed waste 3 coming out of the discharge nozzle 20.

[0039] In the above, the crushing arm 55 of the crushing device 52 is shown to be driven by the rotating shaft 23 of the screw 4 of the compressed body manufacturing device 51. In other words, the crushing device 52 is shown to be driven integrally with the compressed body manufacturing device 51. However, it is also acceptable for them to be driven separately. More specifically, it is also acceptable for the crushing arm 55 of the crushing device 52 to be driven by a drive device other than the rotating shaft 23. In that case, it is possible to control the compressed body manufacturing device 51 and the crushing device 52 to operate under optimal conditions individually.

[0040] The screws 4 can also be arranged side by side in a horizontal direction, for example.

[0041] The operation of the granulation manufacturing apparatus configured as described above will be explained.

[0042] As shown in Figure 1, with the screw 4 rotated by the electric motor 25, plastic waste 3 is fed into the casing 2 from the inlet 10. The fed plastic waste 3 is kneaded and compressed as it is sent downstream by the rotating screw 4, resulting in compaction and heating, and the compressed body is discharged downstream from the opening 56 of the discharge nozzle 20. In other words, the plastic waste 3 is softened and compressed at the downstream end of the screw 4, thereby reducing its volume.

[0043] The compressed plastic waste 3 discharged from the opening 56 of the discharge nozzle 20 strikes the crushing arm 55, which rotates integrally with the screw 4, and is crushed by the crushing arm 55. As a result, the plastic waste 3 introduced into the casing 2 has an increased bulk density compared to the original waste 3 and is formed into a granular material with a lower particle size.

[0044] This granulated material is not a tightly packed pellet like those obtained with the apparatus described in Patent Document 1, but is formed into granules that are not tightly bonded to each other. Moreover, the plastics with low bulk density, such as packaging materials contained in the waste 3, shrink and granulate with other waste materials, resulting in a granulated material with a lower particle size than the original waste 3. As a result, it has better flammability than known hard, lump-shaped pellets. Therefore, it is suitable for use as fuel in melting furnaces and the like.

[0045] It is preferable to adjust the operating conditions of the compression manufacturing device 51 and the crushing device 52 so that the particle size of the granules is 90% by mass of particles smaller than 50 mm and 100% by mass of particles smaller than 100 mm. When the plastic waste 3 is a mixture of various plastics, the granules are usually a mixture of these multiple types of granules. Such granules have the advantage that they are less likely to cause blockages in the supply path when supplied to a melting furnace or the like as fuel. Moreover, such granules can be obtained without consuming a large amount of energy in the compression manufacturing device 51 and the crushing device 52. Furthermore, because the bulk density is increased and the particle size is low, a fuel in the form of granules with good combustibility can be obtained.

[0046] The granules preferably have a bulk density of 0.2 to 0.4. Granules with a bulk density in this range are not excessively compacted, and therefore have the advantage of being less likely to clog the supply path when supplied to a melting furnace or the like as fuel. Moreover, granules with such a bulk density can be obtained without consuming a large amount of energy in the compressed body manufacturing device 51 or the crushing device 52. Furthermore, because they are not excessively compacted, fuel in the form of granules with good combustibility can be obtained.

[0047] In order to manufacture granules in the above-described form, it is necessary to configure the compressed body manufacturing apparatus 51 and the crushing apparatus 52 appropriately. In particular, it is preferable to adjust the distance between the opening 56 of the discharge nozzle 20 and the crushing arm 55 to a value between 0.05 times and 0.2 times the diameter 58 of the opening 56, depending on the type of plastic contained in the waste 3, i.e., its composition. For example, when the diameter 58 of the opening 56 is about 100 mm, the distance 57 between the crushing arm 55 and the opening 56 is preferably about 5 to 20 mm. As a result, the compressed body discharged from the opening 56 of the discharge nozzle 20 is crushed well by the crushing arm 55 of the crushing apparatus 52 without being sheared while still compressed.

[0048] Furthermore, it is preferable to appropriately set the L / D ratio, where D is the diameter 58 of the discharge nozzle 20 and L is the length of the discharge nozzle 20, according to the type of plastic, i.e., its composition. In some cases, the shape of the discharge nozzle 20 can also be tapered.

[0049] The screw 4 can be installed individually or in multiples as described above inside the casing 2. Similarly, the discharge nozzle 20 can be installed individually or in multiples spaced sufficiently apart from each other. In particular, when multiple screws 4 are installed, the compressed material discharged from the discharge nozzle 20 will be correspondingly larger. To discharge a large compressed material, the diameter 58 of the opening 56 of the discharge nozzle 20 will also be large. For example, the diameter 58 can be set to 90 mm or more, in which case a compressed material suitable for forming granulated materials of various specific particle sizes as described above can be easily sent from the discharge nozzle 20 towards the crushing device 52.

[0050] The large diameter 58 of the discharge nozzle 20 prevents the compressed material discharged from the nozzle 20 from becoming too dense. In other words, it prevents the compressed material from becoming too hard and unsuitable for crushing by the crushing device 52. Furthermore, if the granules obtained by the crushing device 52 are too hard and compacted, their combustibility in a melting furnace or the like using them as fuel may be poor, but this can be prevented.

[0051] Furthermore, if the diameter 58 of the opening 56 of the discharge nozzle 20 is large, it is possible to prevent problems such as long objects like wire accumulating inside the compressed body manufacturing device 51. In other words, if the diameter 58 of the opening 56 of the discharge nozzle 20 is large, foreign matter contained in the plastic waste 3 can pass through the nozzle 20 and be discharged more easily, and therefore it is possible to prevent foreign matter from accumulating inside the compressed body manufacturing device 51.

[0052] When waste 3 is compressed in the compressed material manufacturing apparatus 51, the pressure causes the waste 3 itself to heat up. At this time, the plastic in the waste 3 often includes various thermoplastics. However, if the waste 3 containing thermoplastics heats up too much, the thermoplastics melt more than expected. As a result, the excess melted thermoplastics solidify at the opening 56 of the discharge nozzle 20, preventing sufficient crushing by the crushing device 52, and resulting in granulated material that is too large in size.

[0053] To prevent such a situation from occurring, it is preferable to appropriately adjust the mass ratio of thermoplastic plastic in the waste 3 fed into the compressed body manufacturing apparatus 51.

[0054] When plastic waste 3 contains urethane resin, it is preferable to supply moisture to the waste 3 before or after it has been fed into the compressed body manufacturing device 51. This is because urethane resin is effectively granulated when moisture is supplied. When waste 3 contains urethane resin, if a compressed body is formed without excessively compacting the waste 3, large pieces of urethane resin may remain. In contrast, when moisture is supplied, the urethane resin becomes powdery when heated, and is well crushed and granulated in the crushing device 52, and its bulk density also increases. The moisture remaining after the urethane resin has been turned into powder evaporates and is dehydrated under the thermal and compression environment inside the compressed body manufacturing device 51. Therefore, the granulated material obtained by crushing does not contain much moisture and becomes a high-quality fuel with a large calorific value.

[0055] Regarding moisture content, if waste 3 is, for example, plastic used for food packaging, and the food contained a lot of moisture, then plastic waste 3 will often have a similarly high moisture content. However, when high-moisture-content plastics are compressed into a compressed body in the compression manufacturing apparatus 51, the moisture evaporates and dehydrates under the aforementioned thermal and compression environment. Therefore, the granules obtained by crushing similarly do not contain much moisture and become a high-quality fuel with a large calorific value. In the melting treatment method for materials to be melted according to the present invention, granules smaller in size than the waste before compression molding are supplied to the melting furnace together with the materials to be melted, and the furnace is heated to a predetermined melting temperature by burning the granules supplied to the melting furnace. This allows the materials to be melted to be suitably treated.

[0056] Plastic waste 3, that is, waste containing plastic, does not need to be 100% plastic; it may contain non-combustible materials or other combustible components as long as it has sufficient calorific value to be used as fuel. [Examples]

[0057] [Example 1] Plastic-containing waste from shredder dust of home appliances and other items was converted into fuel. This waste mainly consisted of hard plastics and urethane, with some metals also present. The detailed composition was 42% by mass of thermoplastic plastics, 51% by mass of other plastics and rubber, 3% by mass of paper, wood, and cloth, and 3% by mass of metal and rubble. The bulk density was 0.15, 80% by mass consisted of particles smaller than 100 mm, and the moisture content was 7.5% by mass.

[0058] The discharge nozzle 20 of the compressed body manufacturing apparatus 51 had a diameter D of 110 mm and a length L of 480 mm. The distance 57 from the opening 56 to the crushing arm 55 was 5 mm. The temperature of the faceplate 18 was set to 120°C.

[0059] The obtained granules had a bulk density of 0.26. The particle size distribution of the granules was 96% by mass (less than 50 mm) and 100% by mass (less than 100 mm). The granules also had a moisture content of 5.3% by mass and a lower heating value of 23730 kJ / kg.

[0060] [Example 2] Industrial waste was converted into fuel. This waste contained foreign materials other than plastic. The detailed composition was 73% by mass of thermoplastics, 22% by mass of paper, wood, and cloth, and 5% by mass of metal and rubble. The breakdown of thermoplastics was 15% by mass of polyethylene, 12% by mass of polypropylene, 25% by mass of polyvinyl chloride, and 21% by mass of other resins. The bulk density was 0.051, 67% by mass of particles smaller than 100 mm, and the moisture content was 21.7% by mass. The distance 57 from the opening 56 to the crushing arm 55 was 15 mm. Figure 3 shows the plastic-containing waste before this fuel conversion treatment.

[0061] The obtained granules had a bulk density of 0.24. The particle size distribution of the granules was 92% by mass for particles smaller than 50 mm and 100% by mass for particles smaller than 100 mm. The granules also had a moisture content of 12.1% by mass and a lower heating value of 19860 kJ / kg. Figure 4 shows the obtained granules, demonstrating that the particle size distribution is lower compared to the plastic-containing waste shown in Figure 3. The units of measurement for the rulers in Figures 3 and 4 are [×10 cm]. [Explanation of Symbols]

[0062] 2 Casing 3 Plastic waste 4 Screws 20 discharge nozzles 51 Compressed Body Manufacturing Apparatus 52. Crushing device 55 Crushing Arm 56 Aperture 57 distance

Claims

1. When manufacturing granules formed from plastic-containing waste, A compressed waste body is produced by compressing the aforementioned waste. A method for producing a granulated material, characterized by crushing the compressed material to obtain a granulated material with a lower particle size than the waste material before compression.

2. When manufacturing compressed waste, the waste is transported and compressed by a screw placed inside the casing. The compressed waste is discharged from an opening in the casing located downstream of the waste transport direction by the screw. The method for manufacturing a granulated body according to claim 1, characterized in that when the compressed body being discharged is crushed, it is crushed by a crushing device provided in a space in front of the opening in the direction of waste transport by the screw.

3. The method for producing granulated material according to claim 2, characterized in that a rotary crushing arm is used as the crushing device.

4. The method for producing a granulated body according to claim 3, characterized in that the distance between the opening and the crushing arm is 0.05 times or more and 0.2 times or less the diameter of the opening.

5. A compression manufacturing apparatus for producing compressed waste by compressing plastic-containing waste, A granulation manufacturing apparatus characterized by having a crushing device for producing granulations with a lower particle size than the waste before compression by crushing the compressed body produced by the compressed body manufacturing apparatus.

6. The compressed body manufacturing equipment is Casing and, A screw is positioned inside the casing and compresses the waste while transporting it inside the casing. The casing has an opening provided in the casing at a downstream position along the direction of waste transport by the screw, for discharging the compressed waste from the casing, The crushing device is The granulation apparatus according to claim 5, characterized in that it is provided with a space between it and the opening in front of the opening in the direction of waste transport by the screw.

7. The apparatus for producing granulated material according to claim 6, characterized in that the crushing device is a rotary crushing arm.

8. The granulation apparatus according to claim 7, characterized in that the distance between the arm and the opening is 0.05 times or more and 0.2 times or less the diameter of the opening.

9. A method for melting materials using granules formed from plastic-containing waste as fuel, A compressed waste body is produced by compressing the aforementioned waste. By crushing the compressed material, a granulated material with a lower particle size than the waste material before compression is produced. A granulated material with a lower particle size than the waste before compression is supplied to the melting furnace together with the material to be melted. A method for melting an object to be melted, characterized in that the granulated material supplied to the melting furnace is burned to bring the inside of the furnace to a predetermined melting temperature and melt the object to be melted.

10. When manufacturing compressed waste, the waste is transported and compressed by a screw placed inside the casing. The compressed waste is discharged from an opening in the casing located downstream of the waste transport direction by the screw. When the discharged compressed material is crushed, it is crushed by a crushing device that is installed in a space in front of the opening in the direction of waste transport by the screw, As a crushing device, a rotary crushing arm is used. The method for melting a material to be melted according to claim 9, characterized in that the distance between the opening and the crushing arm is 0.05 times or more and 0.2 times or less the diameter of the opening.

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