Treatment apparatus for waste plastics and treatment method for waste plastics

Abstract

A waste plastic processing apparatus includes: a wind sifting device (10) to which waste plastic is supplied; a mechanism (20) to lump the waste plastic separated as light specific gravity matter in the wind sifting device (10); and a coke oven (30) into which the waste plastic separated as heavy specific gravity matter in the wind sifting device (10) and the lumped waste plastic are charged, the coke oven performing thermal decomposition on the waste plastic.

Description

Technical Field

[0001] This invention relates to equipment and methods for treating waste plastics. Background Technology

[0002] It is known to produce coke by dry distillation of coal in a coking oven and to recycle waste plastics by thermal decomposition. For example, Patent Document 1 describes a technique for thermally decomposing waste plastics by loading them into a space formed at the top of a coking oven. Alternatively, waste plastics can be pre-mixed with the coal loaded into the coking oven.

[0003] Existing technical documents Patent documents Patent Document 1: Japanese Patent No. 2967329 Summary of the Invention

[0004] The problem that the invention aims to solve As mentioned above, when using a coking oven to process waste plastics, in order to prevent flaky waste plastics from being discharged untreated and mixed into the exhaust gas (COG), the waste plastics are charged into the coking oven in a block form, for example, by extrusion-based granulation or heating to reduce volume. However, in this case, the block formation process becomes a bottleneck and may prevent the increase in the amount of waste plastics that can be processed.

[0005] Therefore, the purpose of this invention is to provide a waste plastic processing device and a waste plastic processing method. In the reuse of waste plastics by thermal decomposition in a coking oven, the processing capacity can be increased by reducing the amount of waste plastics that are in clumps before being loaded into the coking oven.

[0006] Methods for solving problems [1] A waste plastic processing device comprising: a wind-powered screening device for supplying waste plastic; a mechanism for forming the waste plastic that is separated as a light substance in the wind-powered screening device into blocks; and a coking oven for loading the waste plastic that is separated as a heavy substance in the wind-powered screening device and the formed waste plastic into blocks, and for thermally decomposing the waste plastic.

[0007] [2] According to the waste plastic treatment equipment described in [1], the coking furnace performs dry distillation on coal and thermal decomposition on the waste plastic, and the waste plastic separated as the heavy material and the lumped waste plastic are loaded into the furnace space formed above the coal during the dry distillation of the coal.

[0008] [3] According to the waste plastic processing equipment described in [1], the waste plastic separated as the heavy material and the block-shaped waste plastic are loaded into the furnace space containing the bottom of the coking furnace.

[0009] [4] According to the waste plastic treatment equipment described in [1], the coking oven performs dry distillation on coal and thermal decomposition on the waste plastic, and the waste plastic treatment equipment also has a mechanism for mixing the waste plastic separated as the heavy material and the lumped waste plastic into the coal, and the coal mixed with the waste plastic is loaded into the coking oven.

[0010] [5] According to the waste plastic treatment equipment described in [1], the coking furnace performs dry distillation on coal and thermal decomposition on the waste plastic. The waste plastic treatment equipment further includes a mechanism for mixing at least a portion of at least one of the waste plastics separated as heavy materials and the waste plastics after lumping into the coal. The coal mixed with at least a portion of at least one of the waste plastics separated as heavy materials and the waste plastics after lumping into the coking furnace is loaded into the coking furnace. The waste plastics that are not mixed into the coal, which are the waste plastics separated as heavy materials and the waste plastics after lumping into the coal, are loaded into the furnace space formed above the coal during the dry distillation of the coal mixed with at least a portion of at least one of the waste plastics separated as heavy materials and the waste plastics after lumping into the coal.

[0011] [6] The waste plastic treatment equipment according to any one of [1] to [5], wherein the wind-powered screening device has a vertical screening column.

[0012] [7] The waste plastic processing equipment according to any one of [1] to [5] includes an extrusion molding machine as the mechanism for forming the waste plastic into blocks.

[0013] [8] A method for treating waste plastics includes the following steps: separating the waste plastics into heavy and light materials by wind screening; forming the waste plastics separated as the light materials into blocks; and loading the waste plastics separated as the heavy materials and the block-formed waste plastics into a coking oven, where the waste plastics are thermally decomposed.

[0014] [9] According to the waste plastic treatment method described in [8], the coking furnace performs dry distillation on coal and thermally decomposes the waste plastics loaded into the coking furnace, and loads the waste plastics separated as the heavy material and the lumped waste plastics into the furnace space formed above the coal during the dry distillation of the coal.

[0015]

[10] According to the waste plastic treatment method described in [8], the waste plastic separated as the heavy material and the block-shaped waste plastic are loaded into the furnace space including the furnace bottom of the coking furnace.

[0016]

[11] According to the waste plastic treatment method described in [8], the coking furnace performs dry distillation on coal and thermally decomposes the waste plastics loaded into the coking furnace. The waste plastic treatment method further includes a step of mixing the waste plastics separated as the heavy material and the lumped waste plastics into the coal, and loading the coal mixed with the waste plastics into the coking furnace.

[0017]

[12] According to the waste plastic treatment method described in [8], the coking furnace performs dry distillation on coal and thermally decomposes the waste plastics charged into the coking furnace. The waste plastic treatment method further includes a step of mixing at least a portion of at least one of the waste plastics separated as the heavy material and the waste plastics after lumping into the coal. The coal mixed with at least a portion of at least one of the waste plastics separated as the heavy material and the waste plastics after lumping into the coking furnace is charged into the coking furnace. The waste plastics separated as the heavy material and the waste plastics after lumping that are not mixed into the coal are charged into the furnace space formed above the coal during the dry distillation of the coal mixed with at least a portion of at least one of the waste plastics separated as the heavy material and the waste plastics after lumping.

[0018]

[13] The waste plastic treatment method according to any one of [8] to

[12] , wherein the coking oven has a riser pipe for discharging gas from the oven, the waste plastic treatment method further includes the following steps: calculating the resistance of the floating matter applied to the riser pipe based on the measurement results of the temperature, flow rate and composition of the gas in the riser pipe; and setting the airflow velocity in the wind screening in such a way as to apply the same resistance to the waste plastic as that in the riser pipe. Attached Figure Description

[0019] Figure 1 This is a diagram showing the overall structure of the waste plastic processing equipment according to the first embodiment of the present invention.

[0020] Figure 2 yes Figure 1 An enlarged view of the wind-powered screening device shown.

[0021] Figure 3 yes Figure 1 An enlarged view of the coking oven shown.

[0022] Figure 4 This is a diagram showing the overall structure of the waste plastic processing equipment according to the second embodiment of the present invention.

[0023] Figure 5 yes Figure 4 An enlarged view of the coking oven shown.

[0024] Figure 6 This is a diagram showing the overall structure of the waste plastic processing equipment according to the third embodiment of the present invention.

[0025] Figure 7 yes Figure 6 An enlarged view of the coking oven shown.

[0026] Figure 8 This is a diagram showing the overall structure of the waste plastic processing equipment according to the fourth embodiment of the present invention.

[0027] Figure 9 It means Figure 8 A diagram showing a modified example of a waste plastic processing device.

[0028] Figure 10 yes Figure 9 An enlarged view of the coking oven shown.

[0029] Figure 11 This is a graph showing the recovery rate of each flow velocity in the wind screening of the embodiment.

[0030] Figure 12 This is a graph showing the measurement results of the thickness of the waste plastic separated by wind screening in the example.

[0031] Figure 13 This is a graph representing the simulation results of the dispersion state inside the coking oven. Detailed Implementation

[0032] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. Furthermore, in this specification and the accompanying drawings, structural elements having substantially the same functional structure are labeled with the same reference numerals, thereby omitting redundant descriptions.

[0033] (First Implementation) Figure 1This is a diagram showing the overall structure of the waste plastic processing equipment according to the first embodiment of the present invention. In this specification, waste plastic refers to waste primarily composed of plastics. Examples of plastics include polystyrene (PS), polyethylene (PE), polypropylene (PP), polyethylene terephthalate (PET), vinyl chloride (PVC), and polyvinylidene chloride (PVDC). In the illustrated example, the processing equipment 1 includes: a wind-powered screening device 10, to which waste plastics are supplied; an extrusion molding machine 20, which is a mechanism for forming blocks of waste plastics separated as lighter materials W2 in the wind-powered screening device 10; and a coking furnace 30, into which waste plastic W, obtained by combining the waste plastics separated as heavier materials W1 in the wind-powered screening device 10 with the waste plastics formed by the extrusion molding machine 20, is loaded. As described later, in this embodiment, the waste plastic W is loaded into the empty space above the coal C formed during the dry distillation of coal C. The combustible gases, tar, and light oil produced by the dry distillation (thermal decomposition) of coal C and waste plastic W are recovered as COG (coke oven gas), and the solid coke is removed from coke oven 30 after the dry distillation is completed.

[0034] Furthermore, regarding the mechanism for supplying the waste plastics separated in the wind-powered screening device 10 to the extruder 20, the mechanism for loading coal and waste plastics into the coke oven 30, and the mechanism for recovering and removing the gas and solid components generated in the coke oven 30, coal loading carts, conveyors, hoppers, or feeders used in known waste plastic processing equipment can be appropriately utilized, therefore detailed descriptions are omitted. Additionally, the extruder 20 is an example of a mechanism for forming waste plastics into blocks. For example, by using a screw extruder to mix the waste plastics, heat them, and compress them, the waste plastics are fused together. Besides this, various devices for forming or granulating waste plastics using furnaces such as rotary kilns for heating and volume reduction can also be used for forming waste plastic blocks.

[0035] Figure 2 yes Figure 1An enlarged view of the wind-powered screening device is shown. The wind-powered screening device 10 in the illustrated example has a vertical screening column 12. While the wind-powered screening device in the embodiments of the present invention is not necessarily limited to having a vertical screening column, it has the advantage of high grading accuracy when it does. In the wind-powered screening device 10, waste plastic is fed into the screening column 12 via the feeder 11, and separated into heavy specific gravity material W1 and light specific gravity material W2 by the airflow generated within the screening column 12 due to the operation of the suction blower 13. The heavy specific gravity material W1 falls within the screening column 12 and is recovered. The light specific gravity material W2 is blown up by the airflow within the screening column 12 and separated from the airflow in the cyclone chamber 14 and is recovered. Here, as described above, the waste plastic separated as heavy specific gravity material W1 is not lumped together before being loaded into the coking oven 30. Therefore, the airflow velocity within the screening column 12 needs to be set so that, after being loaded into the coke oven 30, the waste plastic with a higher specific gravity W1 will not be mixed into the COG recycling path in an untreated state. In this embodiment, the flow velocity of the screening column 12 at a position P above the outlet of the feeder 11 is set using a calculation method described later.

[0036] Furthermore, this instruction manual describes the separation of waste plastics into heavier materials W1 and lighter materials W2 by wind screening. However, the terms "heavier materials" and "lighter materials" do not necessarily mean that these waste plastics have different specific gravities. Although these waste plastics may have the same specific gravity as materials, they are separated into heavier materials (the side that falls) and lighter materials (the side that is scattered and recycled) in wind screening based on differences in size such as the thickness after crushing.

[0037] Figure 3 yes Figure 1 The diagram shows an enlarged view of the coking oven. The coking oven 30 is used to dry distill coal C to produce coke. Waste plastic W is fed into the furnace space SP, formed above the coal C during the dry distillation, through the inlet 31 at the top of the oven. The furnace space SP above the coal C is formed by the shrinkage of the coal C during dry distillation within the coking oven 30. Therefore, the feeding of waste plastic W into the coking oven 30 is carried out after a predetermined time has elapsed since the dry distillation of coal C began using the coking oven 30. Combustible gases, tar, and light oil gasified by the dry distillation (thermal decomposition) of coal C and waste plastic W are recovered as COG via the riser 32.

[0038] As is common to the embodiments described below, in the processing in the coking oven 30 described above, if the waste plastic W that has not yet been thermally decomposed is scattered by the rising airflow inside the oven and rises in the riser pipe 32, the waste plastic W may mix into the gas recovery processing path after the riser pipe 32, potentially affecting the quality of the recovered light oil, or causing blockages in equipment such as nozzles. As described above, in this embodiment, the waste plastic separated as a light specific gravity material W2 in the air screening device 10 is charged into the coking oven 30 after being lumped together, thus suppressing the scattering of waste plastic within the coking oven 30. Moreover, as explained below, by setting the airflow velocity in the air screening device 10 to a range where the heavy specific gravity material W1 waste plastic does not rise in the riser pipe 32, the impact of the aforementioned scattering of waste plastic can be reduced more reliably.

[0039] (Second Implementation) Next, the second embodiment of the present invention will be described. Coke ovens are typically constructed as furnace groups with multiple furnaces (carbonization chambers) and combustion chambers that heat them arranged alternately. However, due to factors such as aging of only some furnaces in the group, they sometimes become unsuitable for coke production. Even in such furnaces, they are heated together with adjacent furnaces, thus becoming wasteful from an energy efficiency point of view. Furthermore, depending on the supply and demand of coke, there may be situations where it is not necessary to produce coke in all furnaces of the furnace group. Therefore, in this embodiment, coke ovens that are not producing coke for reasons such as those described above are effectively utilized, increasing the amount of waste plastics processed.

[0040] Figure 4 This diagram illustrates the overall structure of the waste plastic processing equipment according to the second embodiment of the present invention. In the illustrated example, the processing equipment 2 includes: an air screening device 10, to which waste plastic is supplied; an extrusion molding machine 20, which is a mechanism for forming blocks of waste plastic separated as light specific gravity W2 in the air screening device 10; and a coking oven 30, into which waste plastic W obtained by combining the waste plastic separated as heavy specific gravity W1 in the air screening device 10 and the waste plastic formed by the extrusion molding machine 20 is loaded. In this embodiment, no coal is loaded into the coking oven 30. Combustible gases, tar, and light oil gasified products generated by the dry distillation (thermal decomposition) of the waste plastic W in the coking oven 30 are recovered in the same way as COG (coke oven gas) produced during coke production, and the solid components are removed from the coking oven 30 after the dry distillation is completed.

[0041] Furthermore, similar to other embodiments, the mechanisms for supplying the waste plastics separated in the wind-screening device 10 to the extruder 20, the mechanisms for loading the waste plastics into the coking oven 30, and the mechanisms for recovering and removing the gas and solid components generated in the coking oven 30 can be appropriately utilized from conveyors, hoppers, or feeders used in known waste plastic processing equipment; therefore, detailed descriptions are omitted. Additionally, the extruder 20 is an example of a mechanism for forming waste plastics into blocks. For example, by using a screw extruder to mix the waste plastics, heat them, and compress them, the waste plastics are fused together. Besides this, various devices for forming or granulating waste plastics using furnaces such as rotary kilns for heating and volume reduction can also be used for forming waste plastic blocks.

[0042] Figure 5 yes Figure 4 The diagram shows an enlarged view of the coking oven. The coking oven 30 is originally used to produce coke by dry distilling the coal it is charged with. However, in the example coking oven 30 shown, no coke is being produced, for example, due to aging or supply and demand conditions, and therefore no coal is charged. In the coking oven 30, waste plastic W is charged into the oven through the charging inlet 31 at the top. Since no coal is charged, the waste plastic W is charged into the oven space SP, which includes the oven bottom B of the coking oven 30. As mentioned above, only a portion of the ovens in the group do not produce coke; therefore, waste plastic can also be charged together with coal in other ovens for thermal decomposition. The timing (point of time) at which waste plastic W is charged into the coking oven 30 in this embodiment is not particularly limited. For example, if other coking ovens in the coking oven group also perform thermal decomposition of waste plastic, the timing (point of time) at which waste plastic is charged into the oven space formed by the shrinkage of coal during dry distillation in other ovens can also be used to charge waste plastic W into the coking oven 30. Combustible gases, tar, and light oil vapors produced by the dry distillation (thermal decomposition) of waste plastic W are recovered via riser 32, just like COG.

[0043] In the coking oven 30 described above, the internal space SP where waste plastic W is charged is larger than the internal space formed above the coal during the dry distillation of coal in other coking ovens that produce coke. Therefore, the amount of waste plastic W charged into the coking oven 30 can be increased compared to other coking ovens. In this case, for example, the amount of waste plastic W charged from the charging inlet 31 at the top of the oven can be increased, or waste plastic W can be charged in other ovens through a path for charging coal (not shown) in addition to the charging inlet 31, or waste plastic W can be charged in other ovens through a path for charging coal (not shown) instead of the charging inlet 31. In addition, even if the same amount of waste plastic W is charged into a coking oven 30 that does not produce coke as in other coking ovens that produce coke, the amount of waste plastic processed is increased compared to, for example, a coking oven that does not produce coke and is not used for waste plastic processing. Therefore, the amount of waste plastic W charged into the coking oven 30 in the embodiments of the present invention is not necessarily limited to a greater amount than that in other coking ovens that produce coke.

[0044] (Third implementation method) Figure 6 This is a diagram illustrating the overall structure of a waste plastic processing apparatus according to one embodiment of the present invention. In the illustrated example, the processing apparatus 3 includes: a wind-screening device 10, to which waste plastic is supplied; an extrusion molding machine 20, which is a mechanism for forming blocks of waste plastic separated as light specific gravity W2 in the wind-screening device 10; a coal mixer 40, which is a mechanism for mixing waste plastic W obtained by combining waste plastic separated as heavy specific gravity W1 in the wind-screening device 10 and waste plastic formed by the extrusion molding machine 20 into coal C; and a coking oven 30, into which coal (C+W) mixed with waste plastic is fed. Combustible gases, tar, and light oil gasified products generated by the dry distillation (thermal decomposition) of coal C and waste plastic W are recovered as COG (coke oven gas), and the solid coke is removed from the coking oven 30 after the dry distillation is completed.

[0045] Furthermore, similarly to other embodiments, the mechanisms for supplying waste plastics separated in the wind-screening device 10 to the extruder 20, the mechanisms for supplying waste plastics to the coal mixer 40, the mechanisms for loading coal mixed with waste plastics into the coke oven 30, and the mechanisms for recovering and removing the gas and solid components generated in the coke oven 30 can be appropriately utilized from coal loading vehicles, conveyors, hoppers, or feeders used in known waste plastic processing equipment; therefore, detailed descriptions are omitted. Additionally, the extruder 20 is an example of a mechanism for forming waste plastics into blocks. For example, by using a screw extruder to mix waste plastics, heat them, and compress them, the waste plastics are fused together. Besides this, various devices for forming or granulating waste plastics using furnaces such as rotary kilns for heating and volume reduction can also be used for forming waste plastic blocks.

[0046] Figure 7 yes Figure 6 The enlarged view of the coking oven shown is provided. The coking oven 30 is used to produce coke by dry distillation of the coal C it is charged with. However, in this embodiment, as described above, waste plastic W is pre-mixed into the coal C (C+W). For example, if it is necessary to increase the amount of waste plastic processed, additional waste plastic (W) can be charged into the furnace space formed above the coal C through the charging inlet 31 at the top of the furnace during the dry distillation of the coal C and waste plastic W. Figure 6 (Not shown in the image). The addition of waste plastic is carried out after a predetermined time has elapsed since the dry distillation of coal C began using coke oven 30. The combustible gases, tar, and light oil produced by the dry distillation (thermal decomposition) of coal C and waste plastic W are recovered as COG via riser pipe 32.

[0047] (Fourth Implementation) Figure 8 This is a diagram showing the overall structure of a waste plastic processing apparatus according to a fourth embodiment of the present invention. In the illustrated example, the processing apparatus 4 includes: an air screening device 10, to which waste plastic is supplied; an extrusion molding machine 20, a mechanism for forming blocks of waste plastic separated as a lighter substance W2 in the air screening device 10; a coal mixer 40, a mechanism for mixing a portion (W2-1) of the waste plastic formed by the extrusion molding machine 20 into coal C; and a coking oven 30, for separately loading coal (C+W2) mixed with waste plastic and waste plastic not mixed with coal. Specifically, the waste plastic not mixed with coal includes waste plastic separated as a heavier substance W1 in the air screening device 10 and the remaining portion (W2-2) of waste plastic formed by the extrusion molding machine 20. These waste plastics are loaded into the furnace space formed above the coal C during the dry distillation of the mixture of coal and waste plastic (C+W2). Combustible gases, tar, and light oil produced by the dry distillation (thermal decomposition) of coal C and waste plastic W are recovered as COG (coke oven gas), while the solid coke is removed from coke oven 30 after the dry distillation is completed.

[0048] Furthermore, similar to other embodiments, the mechanisms for supplying waste plastics separated in the wind-powered screening device 10 to the extruder 20, the mechanisms for supplying waste plastics to the coal mixer 40, the mechanisms for loading coal mixed with waste plastics and waste plastics not mixed with coal into the coke oven 30, and the mechanisms for recovering and removing the gas and solid components generated in the coke oven 30 can be appropriately utilized from coal loading vehicles, conveyors, hoppers, or feeders used in known waste plastic processing equipment; therefore, detailed descriptions are omitted. Additionally, the extruder 20 is an example of a mechanism for forming waste plastics into blocks. For example, by using a screw extruder to mix waste plastics, heat them, and compress them, the waste plastics are fused together. Besides this, various devices for forming or granulating waste plastics using furnaces such as rotary kilns for heating and volume reduction can also be used for forming waste plastic blocks.

[0049] Figure 9 It means Figure 8 The diagram shows a modified example of the waste plastic processing equipment. In the illustrated example, all the waste plastic W2, after being lumped together by the extruder 20, is mixed with coal C by the coking machine 40. In this case, only the waste plastic separated as a heavy component W1 in the air screening device 10 is directly fed into the coking oven 30 without being mixed with coal. For example, the proportion of heavy component W1 in the waste plastic transported into the processing equipment 1 is higher than that of coal. Figure 8 In cases where the density is high, the loading method into the coke oven 30 can also be distinguished by the heavy material W1 and the block-shaped waste plastic W2.

[0050] In other implementations, it can also be with Figure 8 and Figure 9 Conversely, in the example shown, a portion of the heavy material W1 is mixed into the coal C, and the remaining portion of the heavy material W1 and the lumped waste plastic W2 are directly loaded into the coking oven 30; or all of the heavy material W1 is mixed into the coal C, and the lumped waste plastic W2 is directly loaded into the coking oven 30. Alternatively, the heavy material W1 and the lumped waste plastic W2 can be mixed and then divided into a portion mixed into the coal C and a portion directly loaded into the coking oven 30. Thus, in the embodiments of the present invention, a portion of the heavy material W1 and the lumped waste plastic W2 is mixed into the coal C, and the remaining portion not mixed into the coal C is directly loaded into the coking oven 30. However, there is no particular limitation on whether the waste plastic in each loading method contains heavy material W1 and lumped waste plastic W2, and the proportion in which they are contained. That is, in this embodiment, at least a portion of at least one of the waste plastics separated as heavy material W1 in the wind screening device 10 and the waste plastics W2 after being lumped together are mixed into coal C by the coal mixer 40.

[0051] The above reference Figure 6 The third and fourth embodiments described can be used separately, for example, depending on the required amount of waste plastic to be processed. In this case, for example, when the amount of waste plastic to be processed is small, Figure 6 The bulk material W1 and the entire amount of the lumped waste plastic are mixed into coal C. In this case, the step of adding waste plastic after the dry distillation of coal C in coke oven 30 can be omitted. If the amount of waste plastic processed increases and exceeds the upper limit for the amount mixed into coal C to ensure coke quality, then... Figure 8 or Figure 9 In this method, waste plastics exceeding the upper limit of the mixing amount are loaded into the furnace space formed above the coal during the dry distillation of the mixture of coal and waste plastics, thereby maximizing the amount of waste plastics that can be processed.

[0052] Figure 10 yes Figure 9 The enlarged view of the coking oven shown is illustrated. Similar to other embodiments, the coking oven 30 is a furnace used to produce coke by dry distillation of the charged coal C. Furthermore, for convenience, the charging method is separated using a heavy material W1 and lumped waste plastic W2. Figure 9 Examples are used to illustrate this, but in cases such as Figure 8 The same applies to other examples. Figure 9 In the example described above, waste plastic W2 is pre-mixed into coal C (C+W2). Then, waste plastic W1 is charged from the charging inlet 31 at the top of the furnace into the furnace space SP formed above coal C during the dry distillation of the mixture of coal C and waste plastic W2. The furnace space SP is formed by the contraction of coal C and waste plastic W2 during the dry distillation within the coking oven 30. Therefore, the charging of waste plastic W1 from the charging inlet 31 is performed after a predetermined time has elapsed since the dry distillation of coal C began in the coking oven 30. Combustible gases, tar, and light oil gasified as COG generated by the dry distillation (thermal decomposition) of coal C and waste plastic W1 are recovered via the riser 32.

[0053] The following describes a method for calculating the airflow velocity in a wind-powered screening device applicable to embodiments of the present invention. The resistance r applied to the suspended matter in the airflow... f (Pa) Using the drag coefficient c D Gas density ρ f (kg / m 3 The gas velocity v (m / s) and drag coefficient c are expressed by the following equation (1). D The particle Reynolds number Re is expressed by the following equation (2), where Re is expressed using the gas density ρ. f (kg / m 3The gas flow rate v (m / s), gas viscosity μ (Pa·s), and characteristic length d (mm) as the thickness of waste plastic are represented by the following formula (3).

[0054] [Formula 1] Based on the measured results of the temperature, flow rate, and composition of the gas in the riser pipe 32 of the coking oven 30, the drag coefficient c can be calculated using equations (2) and (3). D Then, equation (1) is used to calculate the resistance r. f A measuring port is provided in the riser pipe 32, and an anemometer, such as a pitot tube, is inserted through the measuring port to measure the anemometer velocity, thereby measuring the gas flow rate. The gas temperature (air temperature) is measured by setting up a thermocouple in conjunction with the pitot tube. Regarding the gas composition, gas is drawn from the pitot tube after the anemometer measurement is completed and sampled through a gas bag, and the composition is quantified using a gas chromatograph. The measuring position is set at the center of the pipe. By performing this, the resistance r exerted on the suspended matter in the riser pipe 32 of the coke oven 30 can be calculated. f Then, by substituting the value of air at room temperature (20℃) from equation (1) into equation (3), the resistance r applied to the powder can be calculated. f The gas flow rate v (m / s). In the example above, the rotational speed of the suction blower 13 is set so that the gas flow rate v (m / s) can be obtained at the upper position P of the screening column 12 of the air screening device 10. Thus, even without clumping, waste plastics that are unlikely to rise in the riser pipe 32 within the coke oven 30 can be separated as heavier material W1 in the air screening device 10.

[0055] In one embodiment of the invention described above, the waste plastics are pre-screened by air, and the waste plastics separated as heavy material W1 are not lumped together before being loaded into the coke oven 30. Therefore, the lumping performed by the extruder 20 is only performed on the waste plastics separated as light material W2 by air screening. As a result, the amount of waste plastic lumped together before being loaded into the coke oven is reduced, and the amount of waste plastic processed can be increased without being limited by the processing volume of the lumping process. More specifically, the amount of waste plastic processed is less limited by the processing speed of the extruder 20. On the other hand, since the waste plastics separated as light material W2 are lumped together, the impact of the scattering of waste plastics in the coke oven 30 is reduced. Furthermore, if the airflow velocity in the air screening is set as described above, the mixing of untreated waste plastic W into the gas recovery processing path can be prevented more reliably.

[0056] Furthermore, in other embodiments, besides the wind-powered screening device 10 exemplified as one embodiment, various types of wind-powered screening devices can be used. For example, the wind-powered screening device is not limited to a device with a vertical screening column 12 as in the example above, but can also be a device that uses horizontal or oblique airflow to separate heavier and lighter materials. If the resistance r in the riser pipe 32 of the coke oven 30 is calculated as described above... f Then it is possible to set the resistance r calculated according to the specifications of the wind screening device. f Equivalent conditions are used to implement wind power screening.

[0057] Example The following describes the results of experiments used to verify the effectiveness of the embodiments of the present invention described above. In the experiments, an MHV-215 suction-type air-powered screening machine (manufactured by Harashima Electric Industry Co., Ltd.) was used to perform air-powered screening on crushed waste plastics that were to be recycled as general waste. The thickness of the waste plastics separated as heavier materials was measured. When measuring the thickness of the waste plastics, calipers were used to measure the thickness at 2 to 3 points on one sample, and the average value was taken. Furthermore, the dispersion state within a coking oven was analyzed using simulations of the measured thickness of the waste plastics.

[0058] Table 1 shows the calculation conditions and results of the airflow velocity in the wind-powered screening device, namely, the measurement results of the temperature, velocity, and composition of the gas in the riser of the coke oven, and the results calculated using equations (1) to (3) above based on these conditions. Additionally, the characteristic length d in equation (3) is 1 mm. The calculated resistance r... f The gas velocity v obtained in air at room temperature (20℃) is 5.0 m / s.

[0059] [Table 1] Figure 11 This is a graph showing the recovery rates at various flow rates in the air-powered screening of the embodiment. Air-powered screening was performed by setting the speed of the suction blower at three different flow rates: 4.0 m / s, 5.0 m / s, and 6.5 m / s at the top of the screening column of the air-powered screener. A correlation was found between the flow rate and the proportion of waste plastic separated as heavier material (recovery rate). The recovery rate (falling weight / input weight) calculated above for a flow rate of 5.0 m / s was 37%. That is, in this experiment, if the flow rate of 5.0 m / s is set appropriately, 37% of the waste plastic is separated into material that can be fed into the coking oven without undergoing a bulking process.

[0060] Figure 12This is a graph showing the measurement results of the thickness of waste plastics separated by the wind screening method according to the embodiment. In the graph, the thickness distribution is expressed as a weight ratio relative to the input amount for the whole waste plastics fed into the wind screening machine, the waste plastics separated as light-weight materials, and the waste plastics separated as heavy-weight materials. The thickness distribution of the waste plastics separated as heavy-weight materials is significantly different from that of the whole waste plastics and the light-weight waste plastics, showing a distribution with a thickness of 2 mm as the central value, which is thicker than the overall distribution.

[0061] Furthermore, in the above measurement results, the minimum thickness of the heavier material in the waste plastic was 0.2 mm. Therefore, as long as the waste plastic with a thickness of 0.2 mm disperses within the coking oven and does not rise to the riser pipe, the flow rate setting of 5.0 m / s in the air-powered screening machine in the above experiment is appropriate. Even without a clumping process, waste plastics with a low probability of rising within the riser pipe in the coking oven can be properly separated.

[0062] Figure 13 This is a graph showing the simulation results of the dispersion state within a coke oven. In the simulation, the flow state of the airflow within the coke oven is first calculated, and then the dispersion trajectory of plastic particles of a specified size is calculated based on this flow field. The plastic particles are assumed to be spherical, and dispersion trajectories are calculated with diameters of 0.1 mm, 0.2 mm, and 1 mm. The results show that with a particle diameter of 0.1 mm, almost all particles disperse and rise within the riser pipe. However, with diameters of 0.2 mm and 1 mm, almost all particles do not disperse and therefore do not penetrate into the riser pipe.

[0063] Based on the simulation results above, it is believed that for waste plastics with a thickness of 0.2 mm or more, even without a clumping process, the likelihood of them rising within the riser pipe of the coking oven is low. Therefore, in the above experiment, it can be seen that a flow rate of 5.0 m / s in the air-powered screening machine can appropriately separate waste plastics that do not require clumping. In the example of waste plastics being recycled separately as general waste, since 37% of the total does not require a clumping process, it can be said that the processing capacity is not limited by the clumping process, and the effect of increasing the processing capacity of waste plastics is significant.

[0064] Furthermore, as described in the embodiments of the present invention, the airflow velocity in the air screening device is calculated based on the specifications of the coke oven and the air screening device, and is therefore not limited to the values ​​in the above embodiments. Additionally, the thickness of the waste plastic separated as a heavier material varies depending on the airflow velocity, and is therefore not limited to the values ​​in the above embodiments. For example, when the gas velocity in the coke oven is low, even thinner plastic particles are difficult to disperse; therefore, waste plastic thinner than 0.2 mm can be separated as a heavier material by setting the airflow velocity in the air screening device to an even lower value.

[0065] Explanation of reference numerals in the attached figures 1,2,3,4…processing equipment; 10…wind screening device; 11…feeder; 12…screening column; 13…suction blower; 14…cyclone chamber; 20…extrusion molding machine; 30…coke oven; 31…loading inlet; 32…ascending pipe; 40…coke mixer; W…waste plastics; W1…heavy materials; W2…light materials; C…coal; SP…furnace space.

Claims

1. A waste plastic processing device, comprising: The wind-powered screening device is supplied with waste plastics; A mechanism for bulking waste plastics separated as lightweight materials in the wind-powered screening device; and A coking oven is used to feed waste plastics that have been separated as heavy materials in the air screening device, as well as the lumped waste plastics, and to thermally decompose the waste plastics.

2. The waste plastic processing equipment according to claim 1, The coking oven performs dry distillation on the coal and thermal decomposition on the waste plastics. The waste plastics separated as the heavy material and the lumped waste plastics are loaded into the furnace space formed above the coal during the dry distillation of the coal.

3. The waste plastic processing equipment according to claim 1, The waste plastics separated as the heavier material and the bulked waste plastics are loaded into the furnace space containing the bottom of the coking furnace.

4. The waste plastic processing equipment according to claim 1, The coking oven performs dry distillation on the coal and thermal decomposition on the waste plastics. The waste plastic processing equipment also includes a mechanism for mixing the waste plastic separated as the heavier material and the lumped waste plastic into the coal. The coal mixed with the waste plastic is fed into the coking oven.

5. The waste plastic processing equipment according to claim 1, The coking oven performs dry distillation on the coal and thermal decomposition on the waste plastics. The waste plastic processing equipment also includes a mechanism for mixing at least a portion of at least one type of waste plastic, which is separated as the heavy component and the bulked waste plastic, into the coal. Coal containing at least a portion of at least one type of waste plastic, which is separated as the heavier component and the lumped waste plastic, is fed into the coking oven. The waste plastics separated as the heavy component and the waste plastics in the lumped form that were not mixed with the coal are charged into the furnace space formed above the coal during the dry distillation of the coal, which contains at least a portion of the waste plastics separated as the heavy component and the waste plastics in the lumped form.

6. The waste plastic processing equipment according to any one of claims 1 to 5, The wind-powered screening device has a vertical screening column.

7. The waste plastic processing equipment according to any one of claims 1 to 5, The mechanism for forming the waste plastic into blocks includes an extrusion molding machine.

8. A method for treating waste plastics, comprising the following steps: Waste plastics are separated into heavier and lighter materials by air screening. The waste plastics separated as the lighter material are grouped into blocks; and The waste plastics separated as the heavy material and the block-shaped waste plastics are loaded into a coking oven, where the waste plastics are thermally decomposed.

9. The method for treating waste plastics according to claim 8, The coking oven performs dry distillation on coal and thermal decomposition on the waste plastics charged into the coking oven. The waste plastics separated as the heavy material and the lumped waste plastics are loaded into the furnace space formed above the coal during the dry distillation of the coal.

10. The method for treating waste plastics according to claim 8, The waste plastics separated as the heavy material and the bulked waste plastics are loaded into the furnace space containing the bottom of the coking furnace.

11. The method for treating waste plastics according to claim 8, The coking oven performs dry distillation on coal and thermal decomposition on the waste plastics charged into the coking oven. The method for treating waste plastics further includes the step of mixing the waste plastics separated as the heavier material and the lumped waste plastics into the coal. The coal mixed with the waste plastic is loaded into the coking oven.

12. The method for treating waste plastics according to claim 8, The coking oven performs dry distillation on coal and thermal decomposition on the waste plastics charged into the coking oven. The method for treating waste plastics further includes the step of mixing at least a portion of at least one type of waste plastic, which is separated as the heavy component and the bulked waste plastic, into the coal. Coal containing at least a portion of at least one type of waste plastic, which is separated as the heavier component and the lumped waste plastic, is charged into the coking oven. The waste plastics separated as the heavy component and the waste plastics in the lumped form that were not mixed with the coal are charged into the furnace space formed above the coal during the dry distillation of the coal, which contains at least a portion of the waste plastics separated as the heavy component and the waste plastics in the lumped form.

13. The method for treating waste plastics according to any one of claims 8 to 12, The coke oven has an ascent pipe for discharging gases from inside the oven. The method for treating waste plastics also includes the following steps: Based on the measurements of the temperature, flow rate, and composition of the gas in the riser, the resistance applied to the suspended matter within the riser is calculated; and The airflow velocity in the wind-powered screening is set in such a way that the same resistance is applied to the waste plastic as that inside the riser pipe.

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