Transport device for waste plastic and storage hopper for waste plastic

Abstract

A storage hopper (21) of a waste plastic transport device has a pyramid or cone-shaped portion. At the pyramid or cone-shaped portion, the discharge performance index G is observed with a vertical stress Pv (kgf / m2) applied to an opening (56) in the lower end from the storage hopper (21) in which a waste plastic (12) is stored, and with a hopper angle θ (°), a cross-sectional area s (m2) of the opening (56), a peripheral length LO(m) of the opening (56), and a straight body portion peripheral length L (m) of the upper end of the storage hopper. A relational expression representing the discharge performance index G is derived using said Pv, s, LO, and θ as variables, a calculation result from the relational expression is a prescribed value or greater, and the value of (s / LO) / L becomes a prescribed value or greater. Thereby, recovered waste plastic can be fed into a carbonization chamber as is or after being subjected to only minor treatment.

Description

Waste plastic transport equipment and waste plastic storage hopper

[0001] The present invention relates to a waste plastic transport device, and more particularly to a waste plastic transport device for transporting waste plastic to be charged into a coke oven carbonization chamber and a waste plastic storage hopper.

[0002] Conventionally, the vast amounts of waste plastic generated as industrial plastic waste and general plastic waste have been disposed of by landfilling or partial incineration. When landfilled, waste plastics are not decomposed by bacteria in the soil, and when incinerated, the high heat output has a negative impact on incinerators. Furthermore, in the case of chlorine-containing waste plastics, the disposal of the chlorine in the exhaust gas poses a problem. Given the predicted future shortage of landfill sites and growing environmental concerns, there is a desire to promote the recycling of waste plastics. Possible recycling methods include reuse as plastic, utilization of the heat generated during combustion, and the use of gases and oils obtained through thermal decomposition during heating as fuels or chemical raw materials.

[0003] For example, Patent Document 1 discloses a method for recycling waste plastics by mixing plastic granules molded at 100 to 160°C with coal and carbonizing the mixture in a coke oven. On the other hand, Patent Document 2 describes that mixing a large amount of plastic reduces the strength of the resulting coke, and that to keep the reduction in coke strength to a few percent, the mass ratio of plastic to coal needs to be 1% or less, and that the amount that can be recycled is limited depending on the target level of coke strength.

[0004] As a method for adding waste plastics to a coke oven for processing, a method is known in which the waste plastics are charged into the space above the coal charged in the carbonization chamber (hereinafter referred to as the "top space").

[0005] Patent Document 2 discloses a method for pyrolysis recycling in which a coke raw material containing 30% by mass or more of non- or slightly caking coal is charged into the carbonization chamber of a coke oven, and then waste plastics are charged into the furnace top space above the coke raw material. The waste plastics are pre-molded to a size where the ratio of sieve openings under 10 mm is 20% by mass or less and the specific surface area is 500 mm. ２ / g or less, and then charging the granules into a carbonization chamber suppresses the rapid generation of gas, making it possible to recycle a large amount of waste plastic. It also states that extrusion molding machines, double-roll molding machines, etc. can be used to pre-mold the waste plastic.

[0006] According to Patent Document 3, in a method in which coke raw materials are first charged into the carbonization chamber of a coke oven and then waste plastics are charged into the top space, it is possible to thermally decompose most of the waste plastics in the high-temperature coke oven, resulting in high-calorie pyrolysis gases containing hydrogen, methane, ethane, propane, etc., which are contained in the coke oven gas generated in the coke oven carbonization chamber by the thermal decomposition of coal and recovered for reuse as an energy source. Patent Document 3 also states that it is preferable to reduce and solidify the waste plastics and use high-density lumps of waste plastics. In an example of the same document, a mixture of waste plastics is reduced and solidified, with an average particle size of approximately 20 mm.

[0007] Patent Document 4 discloses a method for producing coke by carbonizing coal in a coke oven and then charging waste plastics into the upper space of the carbonization chamber. The document also describes a method for charging polymer waste while shielding it from the atmosphere, in which a hopper is provided on a charging car and a cylindrical chute is set at the coal inlet of the coke oven to charge the waste (see Figure 5 of the document).

[0008] Patent Document 5 discloses a method in which a coke oven is provided with a carbonization chamber in which no coal is charged, waste plastics are charged into the carbonization chamber while heating the interior of the carbonization chamber to a predetermined temperature, and pyrolysis is carried out, and the pyrolysis gas is recovered together with the coke oven gas. According to Figure 1 of the same document, waste plastics are charged into a coal car through a loading hopper for waste plastics and a damper at its bottom, and further through a charge hopper below that and a damper at its bottom, and then through a charging port.

[0009] Patent Document 6 discloses a method for charging coal and waste plastics into a coke oven, in which waste plastics are loaded into a charge hopper of a coal-loading car, followed by coal, and the loaded raw materials are removed from the bottom of the charge hopper and charged into the carbonization chamber. According to Figure 1 of the document, a waste plastic storage tank is located adjacent to the coal tower, and a weighing hopper is located below it. First, waste plastics are dropped into the charge hopper of the coal-loading car from the weighing hopper, and then a predetermined amount of coal is loaded from the coal tower 30 onto the waste plastics previously loaded into the charge hopper by normal operation. Next, as shown in Figure 4, the raw materials from the charge hopper, with the waste plastics at the bottom and the coal above them, are removed and charged into the carbonization chamber using the same operation as normal raw material charging.

[0010] Patent Document 7 discloses a method of charging coal, waste plastics, and coal from below into a charge hopper of a coal charging vehicle, and then charging the coal and waste plastics from the charge hopper into the carbonization chamber of a coke oven. Figure 1 shows a waste plastic bin into which waste plastics are charged and a coal bin into which coal is charged.

[0011] JP 2001-49261 JP 2019-135278 JP 2002-47494 JP 4-41588 JP 10-237454 JP 09-132780 JP 2001-115163

[0012] Chemical Engineering Handbook, 5th Revised Edition, March 18, 1988, pp. 868-869

[0013] In a method of treating waste plastics by charging them into the furnace top space 5 above the charged coal 11 in the carbonization chamber 2 of a coke oven 1 (see FIG. 10 ), a transport device is required to transport the waste plastics 12 to be charged into the carbonization chamber 2 to the top of the coke oven. Typically, as shown in FIG. 10 , the waste plastics 12 are transported to the vicinity of the coke oven by a truck 45 or the like, and then the waste plastics 12 are loaded from the truck 45 into an above-ground hopper 22. Above the coke oven, an above-ground hopper 23 for the waste plastics is disposed. The above-ground hoppers 23 are disposed in the same number as the charging openings 4 in the furnace length direction of the carbonization chamber 2. To transport the waste plastics 12 from the above-ground hopper 22 to the above-ground hopper 23, the waste plastics 12 are discharged from a discharge device 24 disposed at the bottom of the above-ground hopper 22, and then lifted to the top of the coke oven by a flight conveyor 25 or the like, where the required amount of waste plastic is discharged into each above-ground hopper 23 by a distribution discharge device 26.

[0014] As a hopper for charging waste plastics 12 through the charging port 4 of the carbonization chamber, a charge hopper for charging coal provided on the coal loading car 41 may be used as is (see Patent Documents 2, 6, and 7), or a charging hopper dedicated to charging waste plastics may be provided on the same coal loading car 41 or on a mobile cart provided separately from the coal loading car 41 so as to be movable in the furnace battery length direction (see Patent Documents 4 and 5). The same number of charge hoppers and charging hoppers as the number of charging ports 4 are arranged in the furnace length direction of the carbonization chamber.

[0015] Regarding the shape of the waste plastics to be charged into the carbonization chamber, Patent Document 2 describes a method of preforming the waste plastics so that the ratio of sieve openings under 10 mm is 20 mass % or less and the specific surface area is 500 mm ２ Patent Document 3 describes that it is preferable to reduce the volume of waste plastics and solidify them, and to use high-density lumps of waste plastics, and in the examples of the same document, a mixture of waste plastics is reduced in volume and solidified to have an average particle size of about 20 mm.

[0016] Premolding or volume-reducing and solidifying recovered waste plastics requires the installation of a processing device. This also increases the processing costs. However, recovered waste plastics vary in size, have low bulk density, and contain membrane-like particles. When premolding or volume-reducing waste plastics, or when loading them directly or only lightly processed into a carbonization chamber, conventional transport devices have been found to encounter problems such as clogging. For example, the waste plastic loading hopper (11) shown in Figure 1 of Patent Document 5 has a small opening at the damper (13a) at its bottom, resulting in clogging. Furthermore, a waste plastic storage tank (20) with a shape similar to that shown in Figure 1 of Patent Document 6 results in accumulation of waste plastics at the bottom of the storage tank (20). In the tanks and hoppers shown in Figures 1 and 3 of Patent Document 7, the cross-sectional area of ​​the hopper is narrowed below the body of the hopper, resulting in a so-called "hanging shelf" condition, which prevents the load (plastic) from descending properly and sequentially, creating a space below, which can cause a stagnation in continuous discharge.

[0017] The present invention aims to provide a waste plastic transport device, particularly a waste plastic transport device for transporting waste plastic to be charged into a coke oven carbonization chamber, which does not cause problems such as the waste plastic clogging the transport device even if the recovered waste plastic is pre-molded and volume-reduced, or even if it is charged into the carbonization chamber as is or after only light processing, and a waste plastic storage hopper.

[0018] That is, the gist of the present invention is as follows: [1] A waste plastic transport device for supplying waste plastic into a coke oven carbonization chamber from a charging port provided in the ceiling of the coke oven carbonization chamber, the waste plastic transport device having a waste plastic storage hopper in the middle of a transport route, the storage hopper having a surface in a pyramidal, rectangular tubular, conical or cylindrical shape with which the waste plastic comes into contact, the lower end of the storage hopper being open, and a vertical stress Pv (kgf / m) acting on the lower end of the storage hopper storing the waste plastic. ２ ), tan θ calculated from the hopper angle θ (°) of the storage hopper, the cross-sectional area s (m ２ ), the peripheral length L of the opening Ｏ (m), the peripheral length L (m) of the upper end of the storage hopper, X, which is the calculation result obtained by substituting the actual value of tan θ into a relational expression representing a dischargeability performance index obtained by observing the dischargeability performance, is equal to or greater than a predetermined value, and (s / L Ｏ ) / L is a predetermined value or more. Ｏ Based on (s / L Ｏ ), and the tan θ as variables. When the surface that the waste plastic contacts is pyramidal, the hopper angle θ refers to the angle between the horizontal plane and a plane that is perpendicular to both the pyramidal surface and the horizontal plane, and when the hopper is conical, the hopper angle θ refers to the angle between the horizontal plane and a plane that is perpendicular to any one of the surfaces that make up the cone and is perpendicular to the horizontal plane (hereinafter referred to as an "orthogonal plane"), and when the hopper is tubular or cylindrical, the hopper angle θ is 90°.

[0019] [2] The relational expression is the following expression (1), and the value of X in expression (1) is 2.00 or more, and the (s / L Ｏ The waste plastic transport device according to [1], wherein the value of X = 1123907·(Pv) / L is 0.025 or more. －１．５５ ・(s / L Ｏ ) ２ ・(tanθ)０．４６ (1)

[0020] [3] The waste plastic transport device according to [1] or [2], characterized in that the storage hoppers include one or more of a ground hopper, a furnace hopper, an input hopper, and a charge hopper. [4] The waste plastic transport device according to [3], characterized in that a waste plastic feeder is disposed at the lower end of one or more of the ground hopper, the furnace hopper, the input hopper, and the charge hopper, and the waste plastic feeder is any one of a screw feeder, a circle feeder, a table feeder, a rake feeder, and an apron feeder.

[0021] [5] A waste plastic storage hopper used in the waste plastic transport device described in any one of [1] to [4].

[0022] The present invention relates to a storage hopper used in a waste plastic transport device for supplying waste plastic into a coke oven carbonization chamber from a charging port provided in the ceiling of the coke oven carbonization chamber. The surface that comes into contact with the waste plastic has a pyramidal or conical portion, and the angle θ is determined by a predetermined definition, and the discharge outlet cross-sectional area s / discharge outlet peripheral length L Ｏ By making the shape of the waste plastic satisfy the desired dischargeability determined by the above, it becomes possible to load the recovered waste plastic into the carbonization chamber as it is or after only light processing, if the recovered waste plastic has been pre-molded and volume-reduced.

[0023] FIG. 1B is a plan view of an example of a storage hopper. FIG. 1C is a front cross-sectional view of an example of a storage hopper taken along the line B-B of FIG. 1A. FIG. 2D is a front cross-sectional view of an example of a storage hopper taken along the line B-B of FIG. 2A. FIG. 3A is a plan view of an example of a storage hopper provided with a screw feeder. FIG. 3B is a front cross-sectional view of an example of a storage hopper provided with a screw feeder. FIG. 3C is a front cross-sectional view of an example of a storage hopper provided with a circle feeder. FIG. 4A is a front cross-sectional view of an example of a storage hopper provided with a circle feeder. FIG. 4A is a plan view of an example of a storage hopper provided with a table feeder. FIG. 5A is a front cross-sectional view of an example of a storage hopper provided with a table feeder. FIG. 5C is a front cross-sectional view of an example of a storage hopper provided with a rake feeder. FIG. 6 is a front cross-sectional view of an example of a storage hopper provided with an apron feeder. FIG. 7 is a diagram showing an example of a transport device for waste plastic in a coke oven. FIG. 8 is a diagram showing an example of a transport device for waste plastic in a coke oven. FIG. 1 is a diagram showing an example of a transport device for waste plastics in a coke oven. FIG. 2 is a perspective view showing an example of a storage hopper. FIG. 3 is a diagram showing the relationship between the discharge index calculation value X and the discharge performance index G. FIG. 4 is a diagram showing the relationship between the hopper angle θ and the discharge performance index G. (s / L Ｏ 1 is a graph showing the relationship between the discharge performance index G and the discharge performance index G.

[0024] The present invention relates to a waste plastic transport device (see FIG. 10 ) for supplying waste plastics 12 into a carbonization chamber 2 of a coke oven 1 through a charging port 4 provided in the ceiling of the carbonization chamber 2, and a waste plastic storage hopper used in the waste plastic transport device. The transport device of the present invention includes a storage hopper of the present invention capable of temporarily storing various types of waste plastics, and a feeder capable of efficiently discharging / supplying the waste plastics from the storage hopper to the next process. As mentioned above, the waste plastics 12 charged into the carbonization chamber 2 have traditionally been pre-molded or volume-reduced solidified waste plastics. In contrast, new waste plastic processing methods, such as crushing irregular shapes to approximately 30 mm, are being considered to simplify pre-processing as much as possible. Without pre-molding or volume-reducing solidification using an extrusion molding machine or double-roll molding machine, the waste plastics retain their original shape as collected, even though they are crushed. It has been found that when waste plastics are pre-molded or pre-reduced, or when the waste plastics are loaded into the carbonization chamber as is or after only minor processing, problems arise such as the waste plastics clogging the transport device that has been commonly used up until now.

[0025] As described above, as shown in Figures 8 to 10, the waste plastics to be charged into the carbonization chamber 2 are transported to the top of the coke oven 1 and then charged into the carbonization chamber. These transport devices include a ground hopper 22 (where the waste plastics are initially supplied by truck or the like from outside), an over-furnace hopper 23 (where the waste plastics to be charged into the coke oven are temporarily and stably stored) at the top of the coke oven, a feed hopper 43 (dedicated to waste plastics, separate from coal, and which preliminarily stores the required amount of waste plastic in each designated charging port and charges the waste plastics 12 through the charging port 4 of the carbonization chamber), and a charge hopper 42 (shared with coal, which preliminarily stores waste plastics in the same way as the feed hopper 43 and charges the waste plastics 12 through the charging port 4 of the carbonization chamber). These are collectively referred to as waste plastic storage hoppers 21. That is, the waste plastic transport device of the present invention has a waste plastic storage hopper 21 along the transport route.

[0026] The storage hopper 21 has a cylindrical upper portion, such as a rectangular tube or cylinder, and a pyramidal, rectangular tube, conical, or cylindrical lower portion. That is, the storage hopper has a pyramidal, rectangular tube, conical, or cylindrical surface that contacts the waste plastic. Because the cross-sectional area of ​​pyramids and cones decreases downward and the lower end has a flat surface, strictly speaking, pyramids are inverted truncated pyramids and cones are inverted truncated cones. Next, the inclination angle (hopper angle θ) of the surfaces constituting the pyramid and cone is defined. In the case of a rectangular tube or cylinder, the hopper angle θ is 90°. The hopper angle θ is defined to be greater than 90° when the target surface 51 is overhanging.

[0027] The case of a pyramid will be described with reference to Figures 1A and 1B. When the pyramid is a square pyramid, there are four faces 51 constituting the pyramid. Figure 1A is a view of the hopper from below (from the bottom end 55 of the pyramid), and the opening 56 at the bottom end 55 of the pyramid is indicated by dotted hatching. In the present invention, for each face constituting the pyramid, the angle formed by the intersection 54 of the face 51 with a plane (orthogonal plane 53) perpendicular to both the face (face 51 in Figure 1) and the horizontal plane 52 is defined as the hopper angle θ. In the example of Figure 1, the faces 51 include a left face 51A, a right face 51B, an upper face 51C, and a lower face 51D in Figure 1A. Of these four faces, the left face 51A will be discussed below. In FIG. 1, a plane perpendicular to both the surface 51A and the horizontal plane 52 is defined as an orthogonal plane 53, an intersection line 54 between the orthogonal plane 53 and the surface 51A is defined, and the angle between the intersection line 54 and the horizontal plane 52 is a hopper angle θ Ａ The B-B cross section is a plane 53 perpendicular to the plane 51. In FIG. 1B, the horizontal plane 52 is shown as a straight line. In FIG. 1B, the hopper angle θ of the plane 51B is θ Ｂ Similarly, the hopper angle θ Ｃ , θ Ｄ can be obtained.

[0028] The case of a conical shape will be described with reference to Figures 2A and 2B. Figure 2A is a view of the hopper viewed from below (from the bottom end 55 of the cone), with the opening 56 at the bottom end 55 of the cone indicated by dotted hatching. The surface 51 constituting the cone is composed of a single curved surface. In the present invention, when a surface (orthogonal surface 53) is assumed to be orthogonal to any one of the surfaces constituting the cone and perpendicular to a horizontal plane 52, the angle between the intersection of the arbitrary surface and the orthogonal surface 53 and the horizontal plane is defined as the hopper angle θ. In the example shown in Figure 2, a portion of the surface 51 (surface 51A in Figure 2 including the intersection line 54) is taken as the arbitrary surface, and the extracted surface 51A is defined as surface 51. A surface (orthogonal surface 53) is assumed to be orthogonal to surface 51A and perpendicular to the horizontal plane 52, and the intersection line 54 between surface 51A and the orthogonal surface 53 is determined. The angle between the intersection line 54 and the horizontal plane 52 is defined as the hopper angle θ (θ Ａ2, the B-B cross section is a plane 53 perpendicular to the plane 51. In FIG. 2B, the horizontal plane 52 is shown as a straight line. In the example shown in FIG. 2, the hopper angle θ of the plane 51A on the left side in the circumferential direction of the cone in FIG. 2A is Ａ The hopper angle θ can be calculated in a similar manner for any direction on the circumference of the cone. Note that if the center of gravity of the opening shape of the upper end 57 of the inverted truncated cone differs from the center of gravity of the opening shape of the lower end 55 in a plan view, the hopper angle θ will be smallest at the position in the circumferential direction where the length of the intersection line 54 is longest when projected onto the plan view. Therefore, to calculate the minimum value of the hopper angle θ, it is sufficient to calculate the hopper angle θ at the position where the length of the intersection line 54 projected onto the plan view is longest.

[0029] A discharge device is disposed 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. The dotted hatched area in Figures 1A and 2A represents the opening 56. In conventional storage hopper 21, the connection portion for the discharge device has a small cross-sectional area. Therefore, a pyramidal or conical portion is provided at the bottom of the storage hopper 21 to reduce the size of the opening 56 at the lower end 55 of the storage hopper 21 accordingly. Because the pyramidal or conical shape is provided for this purpose, the hopper angle θ has traditionally been approximately 60 to 90 degrees. When using pre-molded or volume-reduced and solidified waste plastic 12, such pyramidal or conical storage hoppers have been used. However, when pre-molded or volume-reduced and solidified waste plastic was used, or even when the waste plastic was used directly or only lightly processed, the waste plastic would clog the storage hopper with the conventional shape.

[0030] Therefore, we came up with the idea that the above problem could be solved if the pyramidal or conical shape of the storage hopper 21 were to satisfy a predetermined relationship between the vertical stress Pv applied to the bottom end 55 of the storage hopper 21 storing waste plastic, the hopper angle θ, and the shape of the opening 56 at the bottom end 55. Therefore, we decided to quantify the effects of the above factors through model experiments. When model experiments were conducted with various changes to Pv, θ, and the discharge outlet dimensions, differences in discharge performance were observed. Furthermore, tests were conducted to confirm discharge performance by changing the discharge outlet dimensions using the model and the actual machine.

[0031] Here, the discharge performance index G was defined as follows for the discharge status from the storage hopper: G = 1: Immediate blockage and discharge stalls Some discharge may occur, but waste plastic remains in the hopper, the discharge speed remains zero, and the entire amount is not discharged. G = 2: Discharge is somehow managed even when stagnation and discharge alternate. Even if a temporary state of zero discharge speed is observed, the entire amount is eventually discharged naturally. G = 3: The discharge pace may slow down slightly, but there is no blockage. Even if fluctuations in the discharge speed are observed, the state of zero discharge speed does not continue for a certain period of time, and discharge is carried out almost continuously, and the entire amount is discharged. G = 4: Stable discharge continues The discharge speed is not stalled and the entire amount is discharged continuously with a stable free fall. If the discharge performance index G is 2 or higher, the discharge performance is determined to be good.

[0032] The vertical stress Pv (unit: kgf / m) applied to the lower end 55 of the storage hopper 21 ２ ) can be obtained by the relational expression shown in the following formula (2) from the Jansen formula (see Non-Patent Document 1). Assuming the storage hopper 21 shown in FIG. 11, the cross-sectional area of ​​the upper end 57 of the storage hopper 21 (c×d in the example of FIG. 11) is calculated as the cross-sectional area A (m ２ ), the peripheral length of the upper end 57 (2(c+d) in the example of FIG. 11) is the peripheral length of the straight body portion L (m). The total height of the storage hopper 21 (hs+hc in the example of FIG. 11) is the total height h (m), and ρ is the packing density of the waste plastic (kg / m ３), k: coefficient (kg / kgf). Pv = ρ ((A / L) / k) (1 - exp(-1 / (((A / L) / k) h))) (2) The vertical stress acting on the bottom surface was measured while changing the height h of the waste plastic piled up in the model hopper, and the coefficient k was determined based on the above formula. k = 0.07 kg / kgf.

[0033] The cross-sectional area of ​​the lower end 55 of the storage hopper 21 shown in FIG. 11 (a×b in the example of FIG. 11) is defined as the opening cross-sectional area s (m ２ ), the peripheral length of the lower end 55 (2(a+b) in the example of FIG. 11) is the opening peripheral length L Ｏ The shape of the opening 56 at the bottom end 55 of the storage hopper 21 is determined by the cross-sectional area s of the opening 56 and the perimeter L of the opening 56. Ｏ Focusing on the index s / L Ｏ Furthermore, the hopper angle was set as the index tanθ. The discharge performance index G obtained from the model experiment was set as Pv,s / L Ｏ When regression was performed using tan θ, a strong correlation was found, and a regression equation expressing G was obtained: G = f (Pv) ｐ · (s / L Ｏ ) ｑ (tan θ) ｒ (3) f, p, q, and r are regression coefficients.

[0034] As a result of the test, the vertical stress Pv applied from the storage hopper to the opening at the bottom end, tan θ calculated from the hopper angle θ, and the cross-sectional area s of the opening / peripheral length L of the opening were calculated. Ｏ It has been found that when the above relationship is set to satisfy a predetermined formula, clogging of the waste plastic 12 in the storage hopper 21 and hanging on the shelves can be prevented even when pre-molding and volume reduction and solidification processing are performed, and even when amorphous waste plastics crushed to about 30 mm are used without pre-molding and volume reduction and solidification processing.

[0035] The predetermined formula is preferably determined taking into consideration the discharge limit index at which waste plastics can be discharged stably.

[0036] A hopper experiment was carried out using a model of the storage hopper 21 shown in Figure 11. As shown in Table 1, various hopper shapes were filled with waste plastic moldings, and the dischargeability of the waste plastics was observed when the opening was opened. The dischargeability performance index G was determined, and the experimental data are shown in Table 1.

[0037]

[0038] In contrast, the variable (Pv) under each condition was calculated based on the above formula (2) and is shown in Table 1. Ｏ ), (tan θ), and using a combination of these multiple data, the discharge performance is observed as the discharge performance index G, and the Pv, s, L Ｏ Based on (s / L Ｏ ), and the tan θ is used as a variable to derive the relational expression representing the discharge performance index G as shown in the following equation (3): G=f·(Pv) ｐ · (s / L Ｏ ) ｑ (tan θ) ｒ (3) Next, a multiple regression calculation was performed on the above formula (3) to determine the coefficients f, p, q, and r. The coefficients were approximately f = 1,123,907, p = -1.55, q = 2, and r = 0.46.

[0039] Therefore, the coefficients of the multiple regression calculation results were substituted for f, p, q, and r on the right side of the above equation (3), and the left side of the equation (3) was set to X, leading to the following equation (1): X = 1123907 (Pv) －１．５５ ・(s / L Ｏ ) ２ ・(tanθ) ０．４６ (1)

[0040] The analysis results are shown in Figure 12. The vertical axis of Figure 12 represents the dischargeability performance index G determined by experiment, and the horizontal axis X represents the calculated discharge index value (the above formula (1)) obtained by calculating the right side of formula (1) using the coefficients determined in the above formula and the variables Pv, S / L, and tan θ determined from each experimental condition. The correlation coefficient between G and X was approximately 0.9, which was a good value. By adjusting each factor so that X ≥ 2.00, it is possible to consider a hopper shape that ensures dischargeability. Furthermore, by adjusting each factor so that X ≥ 2.50, it is possible to achieve a hopper shape with even better dischargeability. Furthermore, it is more preferable to set X ≥ 3.00. It is preferable to set the upper limit of X to 6.00.

[0041] Figure 13 shows the relationship between the hopper angle θ and the discharge performance index G from the experimental data in Table 1. When θ<60°, G=1, and discharge could not be ensured. Therefore, to ensure discharge, θ≧60° is preferable. Also, θ≦75° is preferable.

[0042] Furthermore, the influence of the outlet size is Ｏ The relationship between the size and dischargeability was examined, and as the dimensions c and d of the storage hopper upper end (straight body part) increased from 1m for small to 2m for medium to large, the ratio s / L required to ensure discharge increased. Ｏ This is because the vertical stress Pv acting on the discharge outlet increases in proportion to the hopper size. Ｏ is divided by the peripheral length L of the upper end of the storage hopper to make it dimensionless (s / L Ｏ ) / L is shown in Figure 14. In Figure 14, the size of the storage hopper is indicated by a circle for small size, a diamond for medium size, and a square for large size. Ｏ It was found that discharge could not be ensured when (s / L<0.025. Ｏ ) / L≧0.025 is preferred. Ｏ The upper limit of ) / L is preferably set to 0.035.

[0043] A discharge device 24 for discharging waste plastic is disposed at the lower end 55 of the storage hopper 21 for waste plastic. The shape of the opening 56 at the lower end 55 of the storage hopper 21 is determined by the size of the discharge device 24 and the size of the waste plastic to be discharged. Conventionally, Ｏ In the past, waste plastics having a shape in which (s / L) is less than 0.025 and the left side X of equation (1) is less than 2 were used. When irregularly shaped waste plastics were used that were crushed to about 30 mm without prior molding or volume reduction and solidification treatment, the waste plastics contained film-like pieces, which sometimes spread and caused clogging in the opening 56 at the bottom end of the storage hopper. In the present invention, as described above, Ｏ ) / L, by determining the value of X on the left side of equation (1), it is possible to effectively prevent clogging at the bottom end of the storage hopper even when using irregular waste plastics that have been crushed to about 30 mm without undergoing pre-molding or volume reduction and solidification processing.

[0044] As mentioned above, the storage hopper 21 of the present invention includes one or both of the above-ground waste plastic hopper 22 and the above-furnace waste plastic hopper 23. Furthermore, the storage hopper 21 of the present invention can be used as a charge hopper 42 or an input hopper 43 mounted on a coal loading car 41 or a mobile carriage that is provided separately from the coal loading car 41 and can be moved in the direction of the furnace battery length (see Figures 8 and 9).

[0045] The storage hopper 21 of the present invention is a hopper having a pyramidal or conical portion, and is calculated from the hopper angle θ of the pyramidal or conical portion, the cross-sectional area s of the opening, and the perimeter length L of the opening. Ｏ and the peripheral length L of the upper end of the storage hopper, ((s / L ＯBy establishing the above-mentioned predetermined relationship between the vertical stress Pv acting on the lower opening and the vertical stress Pv at the lower end of the storage hopper 21, favorable results can be obtained. Because the shape of the opening 56 at the lower end 55 of the storage hopper 21 ensures more stable discharge than conventional designs, the discharge device 24 provided below the lower end 55 of the storage hopper 21 must be large enough to handle the waste plastic discharged through such a large opening. In the present invention, this problem can be solved by using any of the screw feeder 31, circle feeder 32, table feeder 33, rake feeder 34, and apron feeder 35 for the waste plastic discharge device 24 provided at the lower end of one or more of the above-ground hopper 22, furnace hopper 23, input hopper 43, and charge hopper 42.

[0046] As shown in Figures 3A and 3B, the screw feeder 31 can be used when there is a large opening 56 at the bottom end 55 of the storage hopper 21. Figures 3A and 3B show an example in which the screw feeder 31 is disposed as the discharge device 24 in the storage hopper 21 (see Figure 8) as the furnace hopper 23. The waste plastic stored in the furnace hopper 23 is discharged by the screw feeder 31 and fed into a charge hopper or a feed hopper located below the discharge opening 28. An example that satisfies the requirements of the present invention is when θ = 70°, tan θ = 2.8, and Pv = 433 kgf / m ２ , s=0.25m ２ , L Ｏ = 2 m, (s / L Ｏ ) / L=0.03, and X on the left side of equation (1)=2.3 can be exemplified.

[0047] As shown in Figures 4A and 4B, the circle feeder 32 has a bottom plate 37 and blades 36 attached to the periphery of the bottom plate 37 at the opening 56 at the lower end 55 of the storage hopper 21. Rotation of the bottom plate 37 rotates the blades 36, which then move the waste plastic to the discharge opening 28 and vertically feed it downward from the discharge opening 28. This arrangement can be used when the storage hopper has a large opening at its lower end. Figures 4A and 4B show an example in which a circle feeder 32 is disposed as the discharge device 24 in a storage hopper 21 (see Figures 8 and 9) that serves as the above-ground hopper 22. The waste plastic stored in the above-ground hopper 22 is discharged by the circle feeder 32 and transported via the discharge opening 28 to the top of the coke oven by the flight conveyor 25 shown in Figures 8 and 9. An example that satisfies the requirements of the present invention is a case where θ = 80°, tan θ = 6.0, and Pv = 452 kgf / m. ２ , s=0.25m ２ , L Ｏ = 2 m, (s / L Ｏ ) / L=0.03, and X on the left side of equation (1)=3.1, for example.

[0048] As shown in Figures 5A and 5B, the table feeder 33 has a pivoting bottom plate 37 attached to the opening 56 at the lower end 55 of the storage hopper 21. The pivoting bottom plate 37 causes the waste plastic to fly in the circumferential direction and supplies it in parallel from the opening 38 to the discharge port 28. This can be used when the lower end 55 of the storage hopper 21 has a large opening 56. Figures 5A and 5B show an example in which a table feeder 33 is disposed as the discharge device 24 in the storage hopper 21 (see Figure 9) as the furnace hopper 23. The waste plastic stored in the furnace hopper 23 is discharged by the table feeder 33 and fed into a charge hopper or feeding hopper located below the discharge port 28. An example that meets the requirements of the present invention is one in which θ = 73°, tan θ = 3.3, and Pv = 373 kgf / m ２ , s=0.25m ２ , L Ｏ = 2 m, (s / L Ｏ ) / L=0.04, and X on the left side of equation (1)=3.1, for example.

[0049] As shown in Figure 6, the rake feeder 34 is provided in the opening 56 at the bottom end 55 of the storage hopper 21. An operating cylinder is provided on one side of the opening 56, and a sliding plate 341 is connected to the cylinder. A scraper plate 342 is provided on the sliding plate, and the surface of the sliding plate 341 facing forward is vertical, while the surface facing backward is inclined. The sliding plate 341 slides in conjunction with the forward and backward movement of the cylinder, sending out waste plastic from the cylinder side of the opening 56 to the opposite side. This can be used when the bottom end 55 of the storage hopper has a large opening 56. An example that meets the requirements of the present invention is when θ = 85°, tan θ = 12, and Pv = 1350 kgf / m ２ , s = 12.3 m ２ , L Ｏ = 14 m, (s / L Ｏ ) / L=0.055, and X>4 on the left side of equation (1) can be exemplified.

[0050] As shown in Figure 7, the apron feeder 35 has a feed conveyor 39 attached to the opening 56 at the bottom end 55 of the storage hopper 21. The waste plastic can be moved as the feed conveyor 39 operates. This can be used when the bottom end 55 of the storage hopper 21 has a large opening 56. An example that satisfies the requirements of the present invention is when θ = 76°, tan θ = 4, and Pv = 784 kgf / m ２ , s=2.3m ２ , L Ｏ = 6 m, (s / L Ｏ ) / L=0.047, and X>4 on the left side of equation (1) can be exemplified.

[0051] In the examples shown in Figures 8 and 9, a circle feeder 32 is used as a waste plastic feeder located at the lower end of the above-ground hopper 22, which is the storage hopper 21. In addition, a screw feeder 31 is used as a waste plastic feeder located at the lower end of the above-furnace hopper 23, which is the storage hopper 21, in the example shown in Figure 8, and a table feeder 33 is used in the example shown in Figure 9.

[0052] The waste plastic stored in the furnace hopper is supplied to a hopper installed on a coal loading car for loading waste plastic into the loading port of the carbonization chamber, and the waste plastic is loaded from the hopper into the carbonization chamber through the loading port of the carbonization chamber.

[0053] As shown in Figure 8, a hopper for loading waste plastics into the loading port 4 of the coking chamber 2 is provided on a coal loading car 41 or a mobile cart that is movable in the direction of the furnace battery length, separate from the coal loading car 41. The same number of loading hoppers 43 as the number of loading ports are arranged in the direction of the furnace length of the coking chamber. Like the storage hopper 21 of the present invention described above, this loading hopper 43 also has a pyramidal or conical surface that contacts the waste plastics. The effects of the present invention can be achieved by setting the value of X on the left side of equation (1) above to a predetermined value or greater, with respect to 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 predetermined value of X on the left side of the equation is 2 or greater, preferably 2.5 or greater, and more preferably 3 or greater. This prevents waste plastics from clogging or hanging in the loading hopper. In the example shown in Figure 8, a screw feeder 31 is used as a waste plastic feeder located at the bottom end of the storage hopper 21, which serves as the input hopper 43. In cases where the hopper angles θ formed by the surfaces constituting the storage hopper are different, it is sufficient that the value of X on the left side of equation (1) is within a preferred range at the position where the hopper angle θ is minimum.

[0054] As shown in Figure 9, a case will be described in which a charge hopper 42 for charging coal, which is provided on a coal loading car 41, is modified and used as a hopper for charging waste plastic into the charging port of the carbonization chamber. The conditions that the storage hopper 21 as the charge hopper 42 must satisfy are the same as those of the loading hopper 43 dedicated to charging waste plastic, which is provided on the coal loading car 41. In the example shown in Figure 9, a table feeder 33 is used as the discharge device located at the lower end of the charge hopper 42.

[0055] DESCRIPTION OF SYMBOLS 1 Coke oven 2 Carbonization chamber 4 Charging port 5 Furnace top space 11 Charging coal 12 Waste plastic 21 Storage hopper 22 Ground hopper 23 Furnace hopper 24 Cutting device 25 Flight conveyor 26 Distribution and cutting device 28 Cutting port 31 Screw feeder 32 Circle feeder 33 Table feeder 34 Rake feeder 341 Sliding plate 342 Scraping plate 35 Apron feeder 36 Blade plate 37 Bottom plate 38 Opening 39 Feed conveyor 41 Coal loading car 42 Charge hopper 43 Input hopper 44 Receiving slope 45 Track 51 Surface 52 Horizontal surface 53 Orthogonal surface 54 Intersection line 55 Lower end 56 Opening 57 Upper end

Claims

1. A waste plastic transport device for supplying waste plastic into a coke oven carbonization chamber from a charging port provided in the ceiling of the coke oven carbonization chamber, the waste plastic transport device having a waste plastic storage hopper in the middle of the transport route, the storage hopper having a part with a surface that comes into contact with the waste plastic in the shape of a pyramid, a square tube, a cone, or a cylinder, the lower end of the storage hopper being open, and the vertical stress Pv (kgf / m) acting on the lower end of the storage hopper storing the waste plastic ２ ), tan θ calculated from the hopper angle θ (°) of the storage hopper, the cross-sectional area s (m ２ ), the peripheral length L of the opening Ｏ (m), the peripheral length L (m) of the upper end of the storage hopper, X, which is the calculation result obtained by substituting the actual value of tan θ into a relational expression representing a dischargeability performance index obtained by observing the dischargeability performance, is equal to or greater than a predetermined value, and (s / L Ｏ ) / L is a predetermined value or more. Ｏ Based on (s / L Ｏ ), and the tan θ as variables. When the surface that the waste plastic contacts is pyramidal, the hopper angle θ refers to the angle between the horizontal plane and a plane that is perpendicular to both the pyramidal surface and the horizontal plane, and when the hopper is conical, the hopper angle θ refers to the angle between the horizontal plane and a plane that is perpendicular to any one of the surfaces that make up the cone and is perpendicular to the horizontal plane (hereinafter referred to as an "orthogonal plane"), and when the hopper is tubular or cylindrical, the hopper angle θ is 90°.

2. The relational expression is the following expression (1), and the value of X in expression (1) is 2.00 or more, and the (s / L Ｏ 2. The transport device for waste plastics according to claim 1, wherein the value of X = 1123907·(Pv) / L is 0.025 or more. －１．５５ ・(s / L Ｏ ) ２ ・(tanθ) ０．４６ (1) 3. The waste plastic transport device according to claim 1 or 2, characterized in that the storage hopper includes one or more of a ground hopper, a furnace hopper, an input hopper, and a charge hopper.

4. The waste plastic transport device according to claim 3, characterized in that a waste plastic feeder is disposed at the lower end of one or more of the above-ground hopper, furnace hopper, input hopper and charge hopper, and the waste plastic feeder is one of a screw feeder, circle feeder, table feeder, rake feeder and apron feeder.

5. A waste plastic storage hopper used in the waste plastic transport device according to claim 1 or 2.

6. A waste plastic storage hopper used in the waste plastic transport device according to claim 3.

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