Conveying device for waste plastics and storage hopper for waste plastics

Abstract

A storage hopper (21) of a conveying device for waste plastics has a pyramidal or conical portion for which a vertical stress, Pv, kgf / m, is assumed to be applied to an opening (56) at a lower end portion from the storage hopper (21) in which waste plastics (12) are stored 2 , a hopper angle, θ, °, is assumed, a cross-sectional area, s, m 2 , of the opening (56) is assumed, a circumference, L O , m, of the opening (56) is assumed, a circumference, L, m, of a straight portion at an upper end portion of the storage hopper is assumed, an actual index of discharge performance, G, is observed, and the above Pv, s, L O , θ are taken as variables to derive an expression representing the actual index of discharge performance, G, a result of calculation of the expression is a prescribed value or more, and a value of (s / L O ) / L is a prescribed value or more, whereby the recovered waste plastics can be directly or after only a slight treatment charged into a carbonization chamber.

Description

Technical Field

[0001] This invention relates to a conveying device for waste plastics, and more particularly to a conveying device for waste plastics to be loaded into the coke oven carbonization chamber and a storage hopper for waste plastics. Background Technology

[0002] Regarding the disposal of waste plastics, which are discharged in large quantities as industrial waste and general plastic waste, the majority has historically been landfilled or partially incinerated. However, waste plastics are not decomposed by microorganisms and bacteria in the soil during landfilling. Incineration generates a large amount of heat, negatively impacting incinerators, and the treatment of chlorine in the exhaust gases becomes problematic, especially with waste plastics containing chlorine. Anticipating future landfill shortages and increasing environmental concerns, there is a desire to promote the recycling of waste plastics. Recycling methods, in addition to reusing the plastics themselves, include utilizing the heat from combustion and using the gases and oils obtained from thermal decomposition as fuels and chemical feedstocks.

[0003] For example, Patent Document 1 discloses a method for reusing waste plastics by mixing plastic granules formed at 100-160°C with coal and then dry distilling the mixture in a coking oven. On the other hand, Patent Document 2 describes that if a large amount of plastic is mixed, the strength of the resulting coke will decrease. In order to keep the decrease in coke strength to around a few percent, the mass ratio of plastic to coal needs to be less than 1%. Depending on the target level of coke strength, the amount that can be reused is limited.

[0004] As a method for adding waste plastics to a coking oven for processing, there is a known method of loading waste plastics into a space above the coal loaded into the carbonization chamber (hereinafter referred to as the "top space").

[0005] Patent document 2 discloses the following method: After loading coke raw material with a non-micro-caking coal blending ratio of 30% or more into the carbonization chamber of a coking oven, waste plastic is loaded into the space above the coke raw material for thermal decomposition and recycling. Through pre-forming, the waste plastic is made into a sieve undersize material with a sieve aperture of 10 mm and a specific surface area of ​​500 mm², with a ratio of 20% or less. 2 The waste plastic is processed into granular material with a particle size of less than 1 g. This granular material is then loaded into a carbonization chamber, thereby suppressing rapid gas generation and enabling the recycling of large quantities of waste plastic. Extrusion molding machines, twin-roll molding machines, etc., can be used in the pre-forming of waste plastic.

[0006] According to Patent Document 3, in a method where coke raw material is first loaded into the carbonization chamber of a coke oven, and then waste plastic is loaded into the top space of the oven, most of the waste plastic can be thermally decomposed in the high-temperature coke oven. As a result, high-calorie thermally decomposed gases containing hydrogen, methane, ethane, propane, etc., are obtained. These gases are contained in the coke oven gases generated in the coke oven carbonization chamber through the thermal decomposition of coal and are thus recovered and reused as an energy source. In Patent Document 3, it is preferable to reduce the volume and solidify the waste plastic, using high-density, blocky waste plastic. In the embodiments of this document, a mixture of waste plastics is reduced in volume and solidified, using waste plastic with an average particle size of approximately 20 mm.

[0007] Patent Document 4 discloses a method for manufacturing coke by loading waste plastics into the upper space of the carbonization chamber after dry distillation of coal in a coking oven. In this document, as a means of loading polymeric waste under atmospheric isolation, a method is described that a hopper is installed on a loading vehicle, and a cylindrical chute is installed at the carbon feed port of the coking oven for loading (see Figure 5 of this document).

[0008] Patent document 5 discloses a method in which a carbonization chamber, which is not to be loaded with coal, is determined in a coking oven. While heating the carbonization chamber to a predetermined temperature, waste plastic is loaded into the carbonization chamber and thermally decomposed. The thermally decomposed gases are then recovered along with the coke oven gases. According to Figure 1 of this document, the waste plastic is loaded into the coal charging car through the loading inlet via a waste plastic loading hopper and its lower baffle, and a loading hopper below it and its lower baffle.

[0009] Patent document 6 discloses a method for loading coal and waste plastics into a coking oven. In this method, waste plastics are added to the charging hopper of a coal charging car, followed by coal. The loaded material is then extracted from the bottom of the charging hopper and loaded into the carbonization chamber. According to Figure 1 of this document, a storage tank for waste plastics is positioned close to the coal tower, with a metering hopper positioned below it. In the charging hopper of the coal charging car, waste plastics are first added from the metering hopper. Then, a predetermined amount of coal is loaded onto the waste plastics that have been loaded from the coal tower 30 into the charging hopper using standard procedures. Next, as shown in Figure 4, the material in the charging hopper, with waste plastics at the bottom and coal on top, is extracted and loaded into the carbonization chamber using the same procedures as during standard material loading.

[0010] Patent document 7 discloses a method in which coal, waste plastic, and coal are fed into the loading hopper of a coal loading vehicle from below, and then the coal and waste plastic are loaded from the loading hopper into the carbonization chamber of a coking oven. Figure 1 shows a waste plastic trough for feeding waste plastic into the loading hopper and a coal trough for feeding coal.

[0011] Existing technical documents Patent documents Patent Document 1: Japanese Patent Application Publication No. 2001-49261 Patent Document 2: Japanese Patent Application Publication No. 2019-135278 Patent Document 3: Japanese Patent Application Publication No. 2002-47494 Patent Document 4: Japanese Patent Application Publication No. 4-41588 Patent Document 5: Japanese Patent Application Publication No. 10-237454 Patent Document 6: Japanese Patent Application Publication No. 09-132780 Patent Document 7: Japanese Patent Application Publication No. 2001-115163 Non-patent literature Non-Patent Document 1: Chemical Engineering Handbook, Revised 5th Edition, Published March 18, 1963, Pages 868-869 Summary of the Invention

[0012] The problem that the invention aims to solve A method for processing waste plastics by loading them into the top space 5 above the coal 11 in the carbonization chamber 2 of the coke oven 1 (see [reference]). Figure 10 In this process, a conveying device is needed to transport the waste plastic 12 loaded into the carbonization chamber 2 to the top of the coking oven. Typically, such as... Figure 10 As shown, waste plastic 12 is transported to the vicinity of the coke oven using a truck 45, and then fed from the truck 45 into the ground hopper 22. A top hopper 23 for waste plastic is located on the top of the coke oven. The number of top hoppers 23 along the length of the carbonization chamber 2 is the same as the number of loading inlets 4. Regarding the transport of waste plastic 12 from the ground hopper 22 to the top hopper 23, the waste plastic 12 is cut out from the cutting device 24 located at the bottom of the ground hopper 22, and then raised to the top of the coke oven by a scraper conveyor 25, etc. The necessary amount of waste plastic is then separated into each top hopper 23 by the distributing cutting device 26.

[0013] As a hopper for feeding waste plastic 12 through the loading inlet 4 of the carbonization chamber, a coal loading hopper provided on the coal charging car 41 can be used directly (see Patent Documents 2, 6, and 7). Alternatively, a dedicated feeding hopper for waste plastic can be provided on the same coal charging car 41 or on a mobile trolley that is different from the coal charging car 41 and can move along the length of the furnace (see Patent Documents 4 and 5). The number of both the coal loading hopper and the feeding hopper is the same as the number of loading inlets 4 along the length of the carbonization chamber.

[0014] Regarding the shape of the waste plastics loaded into the carbonization chamber, Patent Document 2 describes a pre-forming process where the proportion of waste plastics that pass through a sieve with a sieve aperture of 10 mm is less than 20% by mass and has a specific surface area of ​​500 mm². 2Granular material of less than / g is then loaded into the carbonization chamber. In Patent Document 3, it is preferred to reduce the volume of waste plastics and solidify them, using waste plastics in the form of high-density lumps. In the embodiment of this document, a mixture of waste plastics is reduced in volume and solidified, using waste plastics with an average particle size of approximately 20mm.

[0015] To preform or reduce the volume of recycled waste plastics, a processing device is required. This increases processing costs. However, recycled waste plastics vary in size, have low bulk density, and contain film-like substances. When preforming or reducing the volume of waste plastics, further processing, such as direct loading or only light processing, into the carbonization chamber can lead to blockages in conventional conveying systems. For example, in Figure 1 of Patent Document 5, the waste plastic loading hopper (11) has a small opening at its lower end (baffle (13a), causing blockages. Furthermore, if the waste plastic storage tank (20) is shaped like that in Figure 1 of Patent Document 6, waste plastic accumulates at the bottom of the tank. The section of the trough or hopper shown in Figures 1 and 3 of Patent Document 7, where the cross-sectional area is reduced below the straight section of the hopper, becomes a so-called "hang-up" state. The appropriate sequential descent of the goods (plastic) stops, creating space in the lower part, which sometimes results in a continuous discharge stoppage.

[0016] The purpose of this invention is to provide a waste plastic conveying device and a waste plastic storage hopper. In the waste plastic conveying device, especially for conveying waste plastic to be loaded into the coke oven carbonization chamber, even if the recycled waste plastic has been pre-shaped and volume-reduced, the waste plastic will not be blocked in the middle of the conveying device even if it is directly or only lightly processed before being loaded into the carbonization chamber.

[0017] Methods for solving problems In other words, the key points of this invention are as follows.

[0018] [1] A waste plastic conveying device for supplying waste plastic into the carbonization chamber from an inlet located at the top of the coke oven carbonization chamber. The waste plastic conveying device has a waste plastic storage hopper midway through the conveying path. A portion of the storage hopper has a pyramidal, square, conical, or cylindrical surface that contacts the waste plastic. The lower end of the storage hopper is open. The vertical stress applied to the lower end of the storage hopper containing waste plastics is Pv, measured in kgf / m. 2tanθ is calculated from the hopper angle θ of the storage hopper, where θ is in degrees. The cross-sectional area of ​​the opening is s, in meters. 2 Let the perimeter of the opening be L. O Let L be the circumference of the upper end of the storage hopper, in meters. Substituting the actual result of tanθ into the formula representing the actual index of discharge performance, the calculated result X is above the specified value, and (s / L) O The value of ) / L is above the specified value. The actual discharge performance index is obtained by observing the actual results of discharge performance. The relation is based on Pv, ​​s, and L. O (s / L) O ), and the relation derived by taking tanθ as a variable, Furthermore, when the surface in contact with the waste plastic is pyramidal, the hopper angle θ refers to the angle formed by the intersection of the face perpendicular to both the face and the horizontal plane with the horizontal plane. When the surface in contact with the waste plastic is conical, the hopper angle θ refers to the angle formed by the intersection of the arbitrary face orthogonal to the face constituting any part of the cone and perpendicular to the horizontal plane (hereinafter referred to as "orthogonal face") with the horizontal plane. When the surface in contact with the waste plastic is square or cylindrical, the hopper angle θ is set to 90°.

[0019] [2] According to the waste plastic conveying device described in [1], The relationship is given by equation (1) below, where the value of X in equation (1) is 2.00 or higher. The (s / L) O The value of ) / L is above 0.025. .

[0020] [3] The waste plastic conveying device according to [1] or [2], The storage hopper includes one or more of the following: ground hopper, furnace top hopper, feeding hopper, and loading hopper.

[0021] [4] According to the waste plastic conveying device described in [3], Waste plastic feeders are provided at the lower end of one or more of the above-ground hopper, furnace top hopper, feeding hopper, and loading hopper. The waste plastic feeder is any one of a screw feeder, a circular feeder, a table feeder, a rake feeder, or an apron feeder.

[0022] [5] A waste plastic storage hopper is used in a waste plastic conveying device as described in any one of [1] to [4].

[0023] In this invention, the storage hopper used in the waste plastic conveying device that supplies waste plastic into the carbonization chamber from the loading inlet located at the top of the coke oven carbonization chamber has a pyramidal or conical portion on the surface in contact with the waste plastic. This is achieved by shaping the hopper to satisfy the angle θ determined by the specified definition, and the ratio of the outlet cross-sectional area s to the outlet perimeter L. O The determined shape of the discharge performance allows recycled waste plastics to be directly or only lightly processed before being loaded into the carbonization chamber, provided that they have been pre-shaped and volume-reduced. Attached Figure Description

[0024] Figure 1A This is a top view showing an example of a storage hopper.

[0025] Figure 1B This is an example of a storage hopper. Figure 1A BB-oriented front view sectional view.

[0026] Figure 2A This is an example top view showing a storage hopper.

[0027] Figure 2B This is an example of a storage hopper. Figure 2A BB-oriented front view sectional view.

[0028] Figure 3A This is a top view showing an example of a storage hopper equipped with a screw feeder.

[0029] Figure 3B This is an example of a storage hopper equipped with a screw feeder. Figure 3A BB-oriented front view sectional view.

[0030] Figure 4A A top view showing an example of a storage hopper equipped with a disc feeder.

[0031] Figure 4B This is an example of a storage hopper equipped with a disc feeder. Figure 4ABB-oriented front view sectional view.

[0032] Figure 5A This is a top view showing an example of a storage hopper equipped with a benchtop feeder.

[0033] Figure 5B This is an example of a storage hopper equipped with a benchtop feeder. Figure 5A BB-oriented front view sectional view.

[0034] Figure 6 This is a front sectional view showing an example of a storage hopper equipped with a rake feeder.

[0035] Figure 7 This is a front sectional view showing an example of a storage hopper equipped with a plate feeder.

[0036] Figure 8 This is a diagram illustrating an example of a waste plastic conveying device in a coking oven.

[0037] Figure 9 This is a diagram illustrating an example of a waste plastic conveying device in a coking oven.

[0038] Figure 10 This is a diagram illustrating an example of a waste plastic conveying device in a coking oven.

[0039] Figure 11 This is a perspective view showing an example of a storage hopper.

[0040] Figure 12 This is a graph showing the relationship between the calculated value of the emission index X and the actual emission performance index G.

[0041] Figure 13 This is a graph showing the relationship between the hopper angle θ and the actual discharge performance index G.

[0042] Figure 14 It means (s / L) O A graph showing the relationship between ) / L and the actual discharge performance index G. Detailed Implementation

[0043] The present invention relates to a waste plastic conveying device for supplying waste plastic 12 from an inlet 4 located at the top of the carbonization chamber 2 of the coking oven 1 into the carbonization chamber (see reference). Figure 10The present invention relates to a waste plastic storage hopper used in the aforementioned waste plastic conveying device. The conveying device of the present invention includes: a storage hopper capable of storing various types of waste plastics at once; and a feeder capable of efficiently discharging / supplying waste plastics from the storage hopper to the next process. As for the shape of the waste plastic 12 loaded into the carbonization chamber 2, conventionally, as described above, it has mostly used shapes formed by pre-forming or volume-reducing solidification of recycled waste plastics. In contrast, as a new waste plastic processing method to be implemented in the future, in order to simplify pre-processing as much as possible, the processing of amorphous waste plastics such as those crushed to about 30 mm has also been studied. Without pre-forming or volume-reducing solidification processing using extrusion molding machines, twin-roll molding machines, etc., although crushing is performed, the shape of the waste plastic at the time of recycling is still maintained. When waste plastics have undergone pre-forming or volume-reducing processing, if it is desired to further load the waste plastics directly or with only light processing into the carbonization chamber, it is known that in conventionally used conveying devices, problems such as blockage of waste plastics occur midway through the conveying device.

[0044] As described above, the conveying device that transports the waste plastic to be loaded into the carbonization chamber 2 to the top of the coke oven 1 and then loads the waste plastic into the carbonization chamber is, for example... Figures 8-10 As shown, the system includes an above-ground hopper 22 (initially supplied with waste plastics from outside via trucks, etc.), a top hopper 23 at the top of the coke oven (for stable, one-time storage of waste plastics to be loaded into the coke oven), an input hopper 43 (dedicated to waste plastics separate from coal and prepared to store the necessary amount of waste plastics at designated loading inlets, with waste plastics 12 fed into the coking chamber via loading inlet 4), and a loading hopper 42 shared with coal, prepared to store waste plastics similarly to input hopper 43, with waste plastics 12 fed into the coking chamber via loading inlet 4). These are collectively referred to as waste plastic storage hoppers 21. In other words, the waste plastic conveying device of the present invention has waste plastic storage hoppers 21 midway along the conveying path.

[0045] The storage hopper 21 is shaped as follows: it has a cylindrical or square section at the top and a pyramidal or square-cylindrical or conical or cylindrical section at the bottom. That is, a portion of the storage hopper has a pyramidal, square-cylindrical, conical, or cylindrical surface that contacts the waste plastic. The cross-sectional area of ​​the pyramid or cone decreases towards the bottom, and it also has a flat section at the bottom. Therefore, strictly speaking, the pyramid can be called an inverted frustum of a pyramid, and the cone can be called an inverted frustum of a cone.

[0046] Next, the inclination angle (hopper angle θ) of the faces constituting the pyramid and cone is defined. Furthermore, in the case of a square or cylindrical shape, the hopper angle θ is 90°. Additionally, the hopper angle θ is defined as exceeding 90° when the surface 51 being objected is overhanging.

[0047] according to Figure 1A , Figure 1B The following explanation addresses the case of a pyramid. When the pyramid is a square pyramid, it has four faces 51 that constitute the pyramid. Figure 1A This is a view of the hopper from below (from the lower end 55 of the pyramid), with the opening 56 of the lower end 55 of the pyramid indicated by dotted shading. In this invention, among the faces constituting the pyramid, the angle formed by the line 54 of the intersection of the face perpendicular to both the face (face 51 in FIG. 1) and the horizontal plane 52 and the horizontal plane 52 is defined as the hopper angle θ. In the example of FIG. 1, as face 51, there are... Figure 1A The four surfaces are: left surface 51A, right surface 51B, upper surface 51C, and lower surface 51D. Among these four surfaces, the left surface 51A will be discussed in the following description. In Figure 1, the surface perpendicular to both surface 51A and the horizontal surface 52 is designated as the orthogonal surface 53. The line of intersection 54 between the orthogonal surface 53 and surface 51A is defined, and the angle formed by the line of intersection 54 and the horizontal surface 52 is the hopper angle θ. A The BB section is orthogonal to plane 53 of plane 51. Figure 1B In the image, the horizontal plane 52 is displayed as a straight line. Figure 1B In the middle, the angle θ of the hopper on surface 51B is θ B The hopper angle θ can also be calculated similarly for surfaces 51C and 51D. C θ D .

[0048] according to Figure 2A , Figure 2B The case of a cone shape will be explained. Figure 2A This is a view of the hopper from below (from the lower end 55 of the cone), with the opening 56 of the lower end 55 of the cone indicated by dotted shading. The surface 51 constituting the cone is formed by a curved surface. In this invention, when a surface (orthogonal surface 53) is conceived that is orthogonal to any part of the surface constituting the cone and perpendicular to the horizontal surface 52, the angle between the line of intersection of this arbitrary surface and the orthogonal surface 53 and the horizontal surface is defined as the hopper angle θ. In the example shown in Figure 2, as an arbitrary surface, a part of surface 51 is taken out (in Figure 2, surface 51A containing the line of intersection 54), and this taken-out surface 51A is defined as surface 51. A surface (orthogonal surface 53) orthogonal to surface 51A and perpendicular to the horizontal surface 52 is conceived, the line of intersection 54 of surface 51A and the orthogonal surface 53 is determined, and the angle between the line of intersection 54 and the horizontal surface 52 is defined as the hopper angle θ. A In Figure 2, section BB is orthogonal to plane 53 of plane 51. Figure 2B In the figure, the horizontal plane 52 is shown as a straight line. In the example shown in Figure 2, for Figure 2A The hopper angle θ of the left face 51A in the circumferential direction of the cone. AThis has been explained. The hopper angle θ can be calculated similarly for any direction along the circumference of the cone. Furthermore, in the top view, when the centroid of the opening shape at the upper end 57 of the inverted frustum differs from that at the lower end 55, the hopper angle θ is smallest at the position where the length of the intersection line 54 projected onto the top view is longest in the circumferential direction. Therefore, after determining the minimum value of the hopper angle θ, the hopper angle θ at the position where the length of the intersection line 54 projected onto the top view is longest can be calculated.

[0049] A cutting device is provided at the lower end 55 of the storage hopper 21. An opening 56 is formed at the lower end 55 of the storage hopper 21. Figure 1A , Figure 2A The shaded area is the opening 56. In conventional devices, due to the small cross-sectional area of ​​the cutting device connection portion at the lower end 55 of the storage hopper 21, a pyramidal or conical portion is provided at the lower part of the storage hopper 21 to reduce the size of the opening 56 at the lower end 55. Because of this pyramidal or conical shape, a hopper angle of approximately 60° to 90° is conventionally used for the aforementioned hopper angle θ. When using conventional pre-formed or volume-reduced cured waste plastic as waste plastic 12, such a pyramidal or conical shaped storage hopper is used. In contrast, when using pre-formed, volume-reduced cured waste plastic, and then using the waste plastic directly or after only slight treatment, waste plastic sometimes becomes clogged in the storage hopper of the existing shape.

[0050] Therefore, it was considered whether the above problem could be solved by incorporating a pyramidal or conical shape into the storage hopper 21, provided that the vertical stress Pv applied to the lower end 55 of the storage hopper 21 containing waste plastic, the hopper angle θ, and the shape of the opening 56 at the lower end 55 satisfy a specified relationship. Therefore, the influence of the above factors was quantified through model experiments. Model experiments were conducted with various changes to Pv, θ, and the discharge outlet size, and the results showed different discharge performance. Furthermore, tests were conducted in both the model and the actual machine to confirm the discharge performance while changing the discharge outlet size.

[0051] Here, the actual discharge performance index G is determined for the discharge condition from the storage hopper as follows.

[0052] G=1: Immediate blockage and discharge of stagnation.

[0053] Some waste plastic is discharged, but the discharge rate remains at zero due to residual waste plastic in the hopper, making it impossible to discharge all of it.

[0054] G=2: Even if there is an alternation between stagnation and expulsion, it can still be expelled.

[0055] Even if a temporary zero-rate expulsion is observed, it will eventually be completely expelled naturally.

[0056] G=3: Sometimes the discharge speed is slightly slower but there is no blockage.

[0057] Even if a change in the discharge rate is observed, the state of zero discharge rate will not last for a certain period of time, but will be discharged in a roughly continuous manner until all discharge is completed.

[0058] G=4: Continuous and stable discharge.

[0059] The discharge speed does not stop; it is continuously and completely discharged through a stable free fall.

[0060] If the actual discharge performance index G is 2 or above, it is judged as good discharge performance.

[0061] Vertical stress Pv (unit: kgf / m) applied to the lower end 55 of the storage hopper 21 2 The equation is derived from Jansen's formula by the following relation (2) (see Non-Patent Literature 1). Imagine Figure 11 The storage hopper 21 shown has a cross-sectional area of ​​the upper end 57 of the storage hopper 21 (in Figure 11 In the example, let c × d be the cross-sectional area A (m²) of the straight section. 2 ), the perimeter of the upper end 57 (in Figure 11 In the example, 2(c+d) is set as the circumference L (m) of the straight section. Additionally, the total height of the storage hopper 21 ( Figure 11 In the example, hs+hc is set as the total height h (m), and ρ is the packing density of waste plastic (kg / m³). 3 ), k: coefficient (kg / kgf).

[0062] While changing the height h of the waste plastic stacked in the model hopper, the vertical stress applied to the lower surface is measured, and the coefficient k is determined based on the above formula. k = 0.07 kg / kgf.

[0063] In addition, Figure 11 The cross-sectional area of ​​the lower end 55 of the storage hopper 21 shown (in) Figure 11 In the example, let a × b) be the opening cross-sectional area s (m²). 2 ), the circumference of the lower end is 55 (in Figure 11 In the example, let 2(a+b) be the perimeter of the opening, L. O (m). Regarding the shape of the opening 56 at the lower end 55 of the storage hopper 21, focus on the cross-sectional area s of the opening 56 and the perimeter L of the opening 56. O And set as the index s / LO Furthermore, the hopper angle is set as the index tanθ. Then, the actual discharge performance index G obtained through the above model experiment is expressed as Pv and s / L. O Regression is performed using tanθ to obtain a strong correlation, resulting in a regression expression representing G.

[0064] f, p, q, and r are regression coefficients.

[0065] Furthermore, the results of the experiments determined that, in a manner satisfying the prescribed relationship, the vertical stress Pv applied from the opening at the lower end of the storage hopper, the tanθ calculated based on the hopper angle θ, and the cross-sectional area s / perimeter L of the opening were determined. O Even when pre-forming, volume reduction and curing treatment is performed, or when irregular waste plastics crushed to about 30mm are used without pre-forming and volume reduction and curing treatment, it is possible to prevent the waste plastics 12 in the storage hopper 21 from becoming clogged or causing bridging.

[0066] The formula specified above is preferably determined by considering the discharge limit index that can stably discharge waste plastics.

[0067] The following is a detailed explanation.

[0068] It has been used Figure 11 The hopper experiment of the storage hopper 21 model is shown. As shown in Table 1, waste plastic molded material was filled with various changes to the shape of the hopper, and the discharge performance of the waste plastic when the opening was opened was observed. The actual discharge performance index G was determined, and the experimental data are shown in Table 1.

[0069] [Table 1] In contrast, the variables (Pv) under each condition are calculated based on equation (2) above and are shown in Table 1. Furthermore, (s / L) are calculated. O Using a combination of these multiple data points (tanθ), the actual result of the discharge performance is observed and used as the actual discharge performance index G. This index G is then used to represent the above-mentioned Pv, based on the above-mentioned s and L. O (s / L) O Using tanθ as a variable, the relationship representing the actual extrusion performance index G is derived as shown in equation (3) below.

[0070] Next, a multiple regression calculation was performed on the above equation (3) to determine the coefficients f, p, q, and r. The coefficients are approximately f=1123907, p=-1.55, q=2, and r=0.46.

[0071] Therefore, by substituting the coefficients of the above multiple regression calculation results into f, p, q, and r on the right side of equation (3) and setting the left side of equation (3) as X, we can derive the following equation (1).

[0072] The analysis results are shown below. Figure 12 . Figure 12 The vertical axis is the actual discharge performance index G determined by experiments, and the horizontal axis X is the discharge index calculated on the right side of equation (1) using the coefficients determined by the above equation and the variables Pv, S / L, and tanθ determined according to various experimental conditions (as in equation (1) above). The correlation coefficient between G and X is about 0.9, which is good. Moreover, by adjusting each factor to make X ≥ 2.00, it is possible to explore the hopper shape that can ensure discharge performance. Furthermore, if each factor is adjusted to make X ≥ 2.50, a hopper shape with even better discharge performance can be obtained. It is even more preferable to set X ≥ 3.00. The upper limit of X is preferably 6.00.

[0073] Figure 13 The graph shows the relationship between the hopper angle θ and the actual discharge performance index G, extracted from the experimental data in Table 1. When θ < 60°, G = 1, and discharge cannot be guaranteed. Therefore, to ensure discharge, θ ≥ 60° is preferred. Furthermore, θ ≤ 75° is preferred.

[0074] Furthermore, the influence of outlet size was investigated on s / L. O The relationship with discharge performance varies, but as the dimensions c and d of the upper end (straight cylinder section) of the storage hopper increase from 1m for small hoppers, 2m for medium hoppers, to 4m for large hoppers, the required discharge volume (s / L) is ensured. O There is a tendency for it to increase. This is because the vertical stress Pv applied to the discharge outlet increases proportionally to the hopper size. To reflect this effect, s / L O Divide by the circumference L of the upper end of the storage hopper, and use it in conjunction with the dimensionless (s / L) O The relationship between ) / L is further rearranged to obtain Figure 14 .exist Figure 14 In the above, regarding the size of the storage hopper, small is represented by ○, medium by ◇, and large by □. It can be seen that in (s / L) O When s / L < 0.025, discharge cannot be guaranteed. Therefore, to ensure discharge, it is preferable to have (s / L) O (s / L) ≥ 0.025. O The upper limit of ) / L is preferably 0.035.

[0075] A cutting device 24 for cutting out waste plastic is provided at the lower end 55 of the waste plastic storage hopper 21. The shape of the opening 56 at the lower end 55 of the storage hopper 21 is determined by the size of the cutting device 24 and the size of the waste plastic being cut out. Conventionally, devices with (s / L) O A storage hopper with a shape where (s / L) is less than 0.025 and the left-hand side X of equation (1) is less than 2. When using amorphous waste plastic broken into pieces of about 30 mm without pre-forming or volume reduction curing, the waste plastic also contains film-like substances, which sometimes expand and cause blockage at the opening 56 at the lower end of the storage hopper. In this invention, by determining (s / L) as described above... O The value of X on the left side of equation (1) can properly prevent blockage at the lower end of the storage hopper, even when using irregularly shaped waste plastics crushed to about 30 mm without pre-forming or volume reduction curing treatment.

[0076] As described above, the storage hopper 21 of the present invention includes one or both of the above-ground waste plastic hopper 22 and the furnace top waste plastic hopper 23. Furthermore, the storage hopper 21 of the present invention can serve as a charging hopper 42 or an input hopper 43 (see reference) installed on a coal charging car 41 or on a moving trolley that is different from the coal charging car 41 and is movable along the furnace length direction. Figure 8 , Figure 9 ) to use.

[0077] For the storage hopper 21 of the present invention, for tanθ, ((s / L) O The relationship between tanθ and Pv can be obtained by setting the relationship specified above, where tanθ is calculated from the angle θ of the hopper in the pyramidal or conical section. O ) / L) represents the cross-sectional area s and the perimeter L of the opening. OThe relationship between the circumference L of the upper end of the storage hopper and the vertical stress Pv applied to the opening at the lower end is given. Compared to the past, the shape of the opening 56 at the lower end 55 of the storage hopper 21 is designed to ensure a stable discharge state. Therefore, the cutting device 24 located below the lower end 55 of the storage hopper 21 also needs to be able to handle the size of the waste plastic discharged from such a large opening. In this invention, the problem can be solved by using any one of the following cutting devices 24 for waste plastic at the lower end of one or more of the waste plastic ground hopper 22, furnace top hopper 23, feeding hopper 43, and charging hopper 42: a screw feeder 31, a circular feeder 32, a table feeder 33, a rake feeder 34, and an apron feeder 35.

[0078] like Figure 3A , Figure 3B As shown, the screw feeder 31 is able to handle situations where there is a large opening 56 at the lower end 55 of the storage hopper 21. Figure 3A , Figure 3B The storage hopper 21, which serves as the furnace top hopper 23 (see reference). Figure 8 An example of configuring a spiral feeder 31 as the cutting device 24 is given. The spiral feeder 31 cuts out the waste plastic stored in the furnace top hopper 23 and feeds it into a charging hopper or a feeding hopper located below the cutting outlet 28. Examples of satisfying the requirements of the present invention include θ=70°, tanθ=2.8, and Pv=433kgf / m³. 2 s=0.25m 2 L O =2m, (s / L) O (1) / L = 0.03, and the example of X = 2.3 on the left side of equation (1).

[0079] like Figure 4A , Figure 4B As shown, the disc feeder 32 has a bottom panel 37 and blade plates 36 disposed around the opening 56 at the lower end 55 of the storage hopper 21. The blade plates 36 rotate with the rotation of the bottom panel 37, and the waste plastic is moved towards the cutting outlet 28 by the blade plates 36 and fed vertically downward from the cutting outlet 28. This design can handle situations where there is a large opening at the lower end of the storage hopper. Figure 4A , Figure 4B The storage hopper 21, which serves as the above-ground hopper 22 (see reference). Figure 8 , Figure 9(Example: A disc feeder 32 is configured as the cutting device 24. Waste plastic stored in the ground hopper 22 is cut out by the disc feeder 32 and passes through the cutting outlet 28.) Figure 8 , Figure 9 The scraper conveyor 25 shown transports the material to the top of the coking oven. Examples of fulfilling the requirements of this invention include θ = 80°, tanθ = 6.0, and Pv = 452 kgf / m. 2 s=0.25m 2 L O =2m, (s / L) O (1) / L = 0.03, and the example of X = 3.1 on the left side of equation (1).

[0080] like Figure 5A , Figure 5B As shown, the benchtop feeder 33 has a rotating bottom plate 37 at the opening 56 of the lower end 55 of the storage hopper 21. The rotating bottom plate 37 causes the waste plastic to scatter in a circumferential direction and be fed parallel to the cutting outlet 28 from the opening 38. This can handle situations where the lower end 55 of the storage hopper 21 has a large opening 56. Figure 5A , Figure 5B The storage hopper 21, which serves as the furnace top hopper 23 (see reference). Figure 9 A benchtop feeder 33 is used as an example of a cutting device 24. The benchtop feeder 33 cuts out the waste plastic stored in the furnace top hopper 23 and feeds it into a charging hopper or a feeding hopper located below the cutting outlet 28. Examples of satisfying the requirements of the present invention include θ = 73°, tanθ = 3.3, and Pv = 373 kgf / m³. 2 s=0.25m 2 L O =2m, (s / L) O (1) / L = 0.04, and the example of X = 3.1 on the left side of equation (1).

[0081] like Figure 6 As shown, a rake feeder 34 is disposed at the opening 56 of the lower end 55 of the storage hopper 21. An actuating cylinder is provided on one side of the opening 56, and a sliding plate 341 is coupled to the cylinder. A scraper 342 is provided on the sliding plate; the forward direction surface of the sliding plate 341 is vertical, and the backward direction surface is inclined. The sliding plate 341 slides in conjunction with the cylinder's forward and backward movements, feeding waste plastic from the cylinder side of the opening 56 to the opposite side. This can handle situations where the lower end 55 of the storage hopper has a large opening 56. Examples of satisfying the requirements of the present invention include θ=85°, tanθ=12, and Pv=1350kgf / m. 2 s=12.3m 2 L O =14m, (s / L)O (1) / L = 0.055, an example of X > 4 on the left side of equation (1).

[0082] like Figure 7 As shown, a plate feeder 35 is equipped with a feeding conveyor 39 at the opening 56 of the lower end 55 of the storage hopper 21. The feeding conveyor 39 moves the waste plastic. This design can accommodate situations where the lower end 55 of the storage hopper 21 has a large opening 56. Examples of fulfilling the requirements of the present invention include θ=76°, tanθ=4, and Pv=784 kgf / m. 2 s=2.3m 2 L O =6m, (s / L) O (1) / L = 0.047, an example of X > 4 on the left side of equation (1).

[0083] exist Figure 8 , Figure 9 In the example shown, a disc feeder 32 is used as a cutting device for waste plastics disposed at the lower end of the ground hopper 22, which serves as the storage hopper 21. Additionally, as a cutting device for waste plastics disposed at the lower end of the furnace top hopper 23, which serves as the storage hopper 21, a disc feeder 32 is used. Figure 8 The example shown uses a screw feeder 31. Figure 9 The example shown uses a benchtop feeder 33.

[0084] Waste plastic stored in the furnace top hopper is fed to a hopper located on the coal charging car for feeding waste plastic into the carbonization chamber. The waste plastic is fed into the carbonization chamber from the hopper through the carbonization chamber's inlet.

[0085] The hopper for feeding waste plastics into the loading inlet 4 of the carbonization chamber 2 is described as follows: Figure 8 As shown, a dedicated feeding hopper 43 for loading waste plastics is installed on a coal charging car 41 or on a mobile trolley that is different from the coal charging car 41 and can move along the length of the furnace. The number of feeding hoppers 43 arranged along the length of the carbonization chamber is the same as the number of loading inlets. Regarding this feeding hopper 43, similar to the storage hopper 21 of the present invention described above, a portion of it has a pyramidal or conical surface in contact with the waste plastics. Regarding the relationship between the hopper angle θ, the vertical stress Pv applied to the opening, and the cross-sectional area S of the opening / the perimeter L of the opening, the effect of the present invention can be achieved by setting the value of the left side X of the above equation (1) to a predetermined value or higher. The predetermined value of the left side X of the equation is 2 or higher, preferably 2.5 or higher, and more preferably 3 or higher. As a result, it is possible to prevent the waste plastics in the feeding hopper from clogging and bridging (hang-up). Figure 8In the example shown, a spiral feeder 31 is used as a cutting device for waste plastic disposed at the lower end of the storage hopper 21, which is the feeding hopper 43. In addition, when the hopper angle θ formed by each surface constituting the storage hopper is different, the value of X on the left side of the above equation (1) is preferably within the range at the position where the hopper angle θ is the smallest.

[0086] As a hopper for feeding waste plastics into the loading inlet of the carbonization chamber, such as Figure 9 As shown, the case where the coal loading hopper 42 installed on the coal loading car 41 is modified for use is explained. The storage hopper 21, which serves as the loading hopper 42, is designed to meet the same conditions as the dedicated feed hopper 43 for loading waste plastics installed on the aforementioned coal loading car 41. Figure 9 In the example shown, a benchtop feeder 33 is used as a cutting device located at the lower end of the loading hopper 42.

[0087] Explanation of reference numerals in the attached figures 1 Coke oven; 2 Carbonization chamber; 4 Loading inlet; 5 Oven top space; 11 Coal loading; 12 Waste plastics; 21 Storage hopper; 22 Ground hopper; 23 Oven top hopper; 24 Cutting device; 25 Scraper conveyor; 26 Distribution cutting device; 28 Cutting outlet; 31 Screw feeder; 32 Disc feeder; 33 Tabletop feeder; 34 Rake feeder; 341 Sliding plate; 342 Scraper; 35 Plate feeder; 36 Blade plate; 37 Bottom plate; 38 Opening; 39 Feeding conveyor; 41 Coal loading car; 42 Loading hopper; 43 Feeding hopper; 44 Receiving ramp; 45 Truck; 51 Surface; 52 Horizontal plane; 53 Orthogonal plane; 54 Intersection line; 55 Lower end; 56 Opening; 57 Upper end.

Claims

1. A waste plastic conveying device for supplying waste plastic into the carbonization chamber from an inlet located at the top of the coke oven carbonization chamber. The waste plastic conveying device has a waste plastic storage hopper midway through the conveying path. A portion of the storage hopper has a pyramidal, square, conical, or cylindrical surface that contacts the waste plastic. The lower end of the storage hopper is open. The vertical stress applied to the lower end of the storage hopper containing waste plastics is Pv, measured in kgf / m. 2 tanθ is calculated from the hopper angle θ of the storage hopper, where θ is in degrees. The cross-sectional area of ​​the opening is s, in meters. 2 Let the perimeter of the opening be L. O Let L be the circumference of the upper end of the storage hopper, in meters. Substituting the actual result of tanθ into the formula representing the actual index of discharge performance, the calculated result X is above the specified value, and (s / L) O The value of ) / L is above the specified value. The actual discharge performance index is obtained by observing the actual results of discharge performance. in, The relationship is based on Pv, ​​s, and L. O The obtained s / L O And the relation derived by taking tanθ as a variable, Furthermore, when the surface in contact with the waste plastic is pyramidal, the hopper angle θ refers to the angle formed by the intersection of the face perpendicular to both the face and the horizontal plane with the horizontal plane. When the surface in contact with the waste plastic is conical, the hopper angle θ refers to the angle formed by the intersection of the arbitrary face orthogonal to the face that constitutes any part of the cone and perpendicular to the horizontal plane, i.e., an orthogonal plane, with the horizontal plane. When the surface in contact with the waste plastic is square or cylindrical, the hopper angle θ is set to 90°.

2. The waste plastic conveying device as described in claim 1, The relationship is given by equation (1) below, where the value of X in equation (1) is 2.00 or higher. The (s / L) O The value of ) / L is above 0.

025. 。 3. The waste plastic conveying device as described in claim 1 or 2, The storage hopper includes one or more of the following: ground hopper, furnace top hopper, feeding hopper, and loading hopper.

4. The waste plastic conveying device as described in claim 3, Waste plastic feeders are provided at the lower end of one or more of the above-ground hopper, furnace top hopper, feeding hopper, and loading hopper. The waste plastic feeder is any one of a screw feeder, disc feeder, table feeder, rake feeder, or plate feeder.

5. A storage hopper for waste plastics, It is used in the waste plastic conveying device as described in claim 1 or 2.

6. A storage hopper for waste plastics, The waste plastic conveying device as described in claim 3.

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