JP2008260871A - Manufacturing method for metallurgy coke utilizing waste plastic molded article - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suppress the reduction of coke strength even when a waste plastic molded article manufactured by adding a much amount of the waste plastic is utilized in a manufacturing method for coke utilizing the waste plastic molded article. <P>SOLUTION: The manufacturing step for the metallurgy coke utilizing the waste plastic molded article includes the crushing step for crushing the waste plastic to be made to the finely crushed plastic having the maximum length of a long side part of 7 mm or less, the extrusion molding step for extrusion-molding the finely crushed plastic while heating/melting the finely crushed plastic in an extrusion molding machine to be made to the bulk type waste plastic molded article having the maximum length of 100 mm or less and a specific surface area of 180 mm<SP>2</SP>/g or less, and the coke manufacturing step for charging the waste plastic molded article and charcoal into a coke furnace and manufacturing the coke. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a method for producing metallurgical coke using waste plastic moldings, and in particular, a coke that can suppress a reduction in coke strength even when the amount of waste plastic charged in a coke oven is increased. It relates to a manufacturing method.

  In recent years, various methods for mixing waste plastics with coal in a coke oven and charging them have been proposed for the treatment of waste plastics such as scrap plastics and used plastics generated in the plastic processing process. However, when a large amount of waste plastic is simply charged, there is a problem that the strength of coke decreases.

  As a method for solving such a problem, for example, waste plastic is crushed to about 20 to 30 mm, and volume-reduced at about 120 ° C. using a screw-type extruder, and this is about 25 mm in diameter and length. 1% by mass or less of waste plastic molding (hereinafter also referred to simply as “molded product”) cut to about 30 to 40 mm and air-cooled or water-cooled on a belt conveyor is charged into a coke oven in advance. A recycling method has been proposed.

  Further, as another solution, for example, waste plastic is partly or wholly melted at a temperature of more than 160 ° C. and not more than 250 ° C., and is compression-molded, whereby a plastic having an apparent density of 0.7 to 1.2 kg / liter. There has also been proposed a method of reusing waste plastic, which is made into a granulated product, and this plastic granulated product is mixed with coal and carbonized in a coke oven (see, for example, Patent Document 1).

JP 2005-126486 A

  By the way, in the said patent document 1, since the apparent density of the molding which shape | molded the waste plastic is small compared with the true specific gravity (about 1.0-1.4 kg / liter) of coal, compaction of a waste plastic molding The effect is reduced and this is thought to affect the strength of the coke.

  However, even if the apparent density of the waste plastic molding is close to the true specific gravity of coal, when coke is produced using waste plastic molding to which a large amount of waste plastic is added, the coke strength still decreases. There was a problem that occurred.

  Therefore, the present invention has been made in view of such problems, and in a method for producing coke using a waste plastic molding, a waste plastic molding manufactured by adding a large amount of waste plastic is used. Even if it exists, it aims at suppressing the fall of coke intensity | strength.

  In order to solve the above-mentioned problems, the present inventors have intensively studied the factors affecting the strength of coke produced using waste plastic moldings, and as a result, the waste plastics in the coke oven The compaction effect due to the apparent density of the molded product does not have a dominant influence, but the contact area between the waste plastic and coal in the coke oven has a dominant influence on the coke strength. I got the knowledge. That is, the larger the contact area between waste plastic and coal in the coke oven, the lower the coke strength.

  As a result of further investigation by the present inventors based on this knowledge, in order to reduce the contact area between the waste plastic and coal in the coke oven, the specific surface area of the waste plastic molding charged in the coke oven is reduced. It came to the idea that it was necessary.

  In addition, the amount of moisture in plastic waste varies greatly due to the effects of water adhering when it is disposed of at home and rainwater that is mixed in due to the weather when it is collected and processed. In many cases, the water content of the waste plastic exceeds 10% by mass. When producing a waste plastic molding using waste plastic having such a high water content, dehydration / deaeration may be incomplete even if the molding machine has a dehydration / deaeration function. In this case, even if the heating temperature in the extrusion molding machine is insufficient, or even if it can be heated, water vapor is trapped in the molded product, voids (nests) are generated inside the manufactured molded product, and the apparent density decreases. Or troubles such as destruction of the molded product may occur during transportation.

  Therefore, the present inventors have studied to solve such a problem regarding the moisture content, and as a result, the waste plastic is finely crushed to a predetermined size or less, so that the gap between the rotary blade and the fixed blade in the crusher is reduced. It was found that the finely crushed plastic heated by the frictional heat is dried while being conveyed by the air current, and the water content of the waste plastic charged into the molding machine can be lowered.

  In addition, since waste plastic is mainly collected as household waste, the types of plastic (polyethylene, polyvinyl chloride, polystyrene, polyethylene terephthalate, urethane, etc.) and the abundance ratio of each plastic vary greatly. There are plastics with various melting points. Therefore, if 20-60 mass% of plastic that melts at a temperature of 150-200 ° C. that can be heated by an extrusion molding machine is contained, the melted plastic can be used as a binder to obtain a sufficiently strong molded product. Therefore, it is preferable.

The present invention has been completed based on the above findings, and the gist thereof is as follows.
(1) Waste plastic is crushed into finely crushed plastic with a maximum length of 7 mm or less at the long side, and the finely crushed plastic is extrusion molded while being heated and melted in an extruder, and the maximum length is 100 mm or less. A bulk plastic waste product having a surface area of 180 mm ² / g or less, and the waste plastic molding and coal are charged into a coke oven to produce coke, and the coke is produced. Method for producing gold coke.
(2) The method for producing metallurgy coke using the waste plastic molding according to (1), wherein an average length of the long side portion of the finely crushed plastic is 2 to 5 mm.
(3) The manufacturing method of the coke for metallurgy using the waste plastic molding as described in (1) or (2) characterized by making the moisture content of the said finely crushed plastic into 2.5 mass% or less.
(4) The content of the low-temperature melting waste plastic having a component that melts at 150 ° C. to 200 ° C. among the components contained in the waste plastic is 20 to 60% by mass with respect to the total mass of the waste plastic molding. A method for producing metallurgical coke using the waste plastic molding according to any one of (1) to (3).
(5) In any one of (1) to (4), coal having a maximum particle size of 10 mm or less and an average particle size of 1 to 3 mm is mixed with the finely crushed plastic in the extruder. A method for producing coke for metallurgy using the waste plastic molding described.
(6) The mass of coal mixed with the finely crushed plastic is 80% by mass or less based on the total mass of the waste plastic molded product. The manufacturing method of coke for metallurgy used.
(7) Production of coke for metallurgy using waste plastic molding according to (5) or (6), wherein the coal to be mixed has a water content of 2.5% by mass or less. Method.

  According to the method for producing coke using the waste plastic molding according to the present invention, the contact area between the waste plastic and the coke oven coal in the coke oven is set by setting the specific surface area of the waste plastic molding to a predetermined value or less. Can be reduced. Therefore, according to this invention, even when it is a case where coke is manufactured using the waste plastic molding manufactured by adding a lot of waste plastics, the fall of coke strength can be suppressed.

  Exemplary embodiments of the present invention will be described below in detail with reference to the accompanying drawings. In addition, in this specification and drawing, about the component which has the substantially same function structure, duplication description is abbreviate | omitted by attaching | subjecting the same code | symbol.

[Causes of reduced coke strength]
First, before explaining the method for producing coke according to an embodiment of the present invention, as a premise, new knowledge obtained by the present inventors, that is, when coke is produced using waste plastic moldings. Next, the knowledge that the coke strength decreases as the contact area between the waste plastic and coal in the coke oven increases is described.

  In general, waste plastic includes aromatic plastics such as polystyrene (PS) and polyethylene terephthalate (PET), and fats such as polyethylene (PE), polypropylene (PP), and polyvinyl chloride (PVC). Contains tribal plastics. Among these, aliphatic plastics have a low melting point of about 150 to 200 ° C., and are almost melted by heating during extrusion molding of waste plastic moldings, but aromatic plastics have a melting point of over 200 ° C. High and remains in waste plastic moldings. In addition, when the aromatic plastic remaining in the waste plastic is charged into the coke oven, it comes into contact with the coke raw material coal, thereby significantly inhibiting the caking property of the coal. This “caking property” is a chemical property of coke oven coal and is a factor that dominates the influence on the strength of coke produced in the coke oven.

  From this, the present inventors, in the production of metallurgy coke using waste plastic molding, has a dominant influence on the coke strength, rather than the consolidation effect by the increase in apparent density It was found that this is a chemical action at the interface between coal and waste plastic. Therefore, in order to suppress a reduction in coke strength, it is necessary to produce a waste plastic molding that reduces the contact area between coal and waste plastic. Of the components in waste plastics, as mentioned above, aromatic plastics significantly inhibit caking due to contact with coal, but aliphatic plastics are caustic even when contacted with coal. Is hardly inhibited.

[Method of producing coke according to one embodiment of the present invention]
A method for producing coke using waste plastic moldings according to an embodiment of the present invention made from the above viewpoint will be described below.

  The method for producing coke using waste plastic moldings according to an embodiment of the present invention includes a crushing step (A) for finely crushing waste plastics, and producing waste plastic moldings by extruding the finely crushed plastics. An extrusion molding step (B), and a coke production step (C) in which the produced waste plastic molding and coal are charged into a coke oven to produce coke. Hereinafter, based on FIG. 1, the outline of the manufacturing method of the coke which concerns on this embodiment is demonstrated. In addition, FIG. 1 is explanatory drawing which shows roughly the manufacturing equipment of the waste plastic molding used for the manufacturing method of the coke which concerns on this embodiment.

(Overview of crushing process (A))
As shown in FIG. 1, first, for example, waste plastic recovered as household waste or industrial waste is finely crushed by a plastic crusher 10 (crushing step). This crushing process may be divided into two stages. For example, after waste plastic is first crushed to obtain a coarse crushed plastic (primary crushing process), the coarse crushed plastic is put into a secondary crusher, While being heated by friction heat, finely crushed plastic may be obtained while being air-flow dried by an air-flow conveying device (secondary crushing step).

  Next, the finely crushed plastic (hereinafter referred to as “finely crushed plastic”) is sucked by, for example, the suction equipment 20 and transported to the quantitative cutting device 30 with a plastic hopper while being dried by airflow transportation. Store it. The suction facility 20 includes a suction device such as a blower and a transport pipe, for example. Next, the cutting amount (mass standard) of the finely crushed plastic stored in the quantitative cutting device 30 with a hopper is determined. Based on the determined cutting amount, the finely crushed plastic is cut out by a certain amount, and the extrusion molding machine 50 To supply. As the extrusion molding machine 50, for example, a screw type extrusion molding machine as shown in FIG. 3 described later can be used. In addition, when coal is mixed in the waste plastic molding, dry coal is stored in advance in the quantitative cutting device 40 with a coal hopper. The dry coal stored in the quantitative cutting device 40 with a hopper has a moisture content of not more than a predetermined amount (for example, 2.5% by mass or less) using coal pulverized as normal coal for a coke oven with a coal dryer. So dried.

(Outline of extrusion molding process (B))
Next, a certain amount of finely crushed plastic cut out from the quantitative cutting device with hopper 30 and, if necessary, a certain amount of coal cut out from the quantitative cutting device with hopper 40 are put into the extruder 50. These are extruded while being heated and melted to produce a lump-shaped waste plastic molding having a small specific surface area (extrusion molding process).

(Outline of coke production process (C))
Finally, the waste plastic molding produced in the extrusion molding step (B) and the coke oven coal are charged into a coke oven to produce coke. At this time, since the waste plastic molding according to the present embodiment has a small specific surface area, the contact area between the waste plastic and coal can be reduced, and the reduction in the strength of the produced coke can be remarkably suppressed. is there. Accordingly, the amount of waste plastic molding can be increased, and a large amount of waste plastic can be reused to contribute to environmental improvement.

  The outline of the method for producing coke according to the present embodiment has been described above. Hereinafter, the steps (A) to (C) described above will be described in detail.

(Details of crushing step (A))
1stly, the detail of a crushing process (A) is demonstrated based on FIG. In addition, FIG. 2 is explanatory drawing which shows the structure of the crusher 10 for plastics used for the crushing process (A) which concerns on this embodiment.

  First, the configuration of the plastic crusher 10 will be described. As shown in FIG. 2, the plastic crusher 10 mainly includes a hopper 12 into which plastic is charged, a drum-shaped crushing rotor 14, a rotary blade 15, a fixed blade 16, and a screen 18.

  In the upper part of the hopper 12, a charging port 12a for charging plastic is formed. Further, the crushing rotor 14 is provided in the hopper 12 and rotates, for example, in the direction of arrow B in FIG. A plurality of rotary blades 15 are provided on the outer periphery of the crushing rotor 14 and rotate together with the crushing rotor 14. The fixed blade 16 is provided at a position close to the outer periphery of the crushing rotor 14 and is fixed to the inner surface of the hopper 12. The screen 18 is provided around the outer peripheral portion on the lower side of the crushing rotor 14 and discharges only fine crushing plastic having a specific size or less to the outside of the crushing machine 10 for plastic. The screen 18 has a predetermined diameter in order to discharge only the finely crushed plastic having a desired size or less from the plastic sheared by the rotation of the fixed blade 16 and the rotary blade 15 to the outside of the plastic crusher 10. It has a mesh shape in which a plurality of holes 18a are formed. In the present embodiment, for example, 8 mmΦ may be selected as the mesh of the screen 18.

  Next, a waste plastic crushing method using the above-described plastic crusher 10 will be described. In this embodiment, waste plastic that has been subjected to mechanical foreign matter removal work such as separation of foreign materials by manual sorting by human vision in advance, separation of iron products, etc. by a magnetic sorter, and separation of heavy materials by wind force is roughly crushed. As shown in FIG. 2, the product (hereinafter referred to as “coarse crushing plastic P1”) is fed into the plastic crusher 1 from the charging port 12a of the hopper 12 (see arrow A in FIG. 2). The roughly crushed plastic P1 is dropped downward, and the fixed blade 16 and the rotating rotary blade 15 shear the roughly crushed plastic P1 to form a finely crushed plastic P2.

  Here, “finely pulverized plastic P2” in the present embodiment refers to those having a long side portion having a maximum length of 7 mm or less, and in this case, the average length of the long side portion is 3 to 4 mm. Is preferred. In addition, the shape of finely crushed plastic is indefinite, and there are various shapes such as a spherical shape, a lump shape, and an elongated string shape. The “long side portion” in the present embodiment is the maximum of a plastic shape such as a spherical shape, a lump shape, and a string shape. It refers to the part that has a length.

  The plastic sheared by the fixed blade 16 and the rotating rotary blade 15 is sieved by the screen 18. In the present embodiment, the hole 18a formed in the screen 18 allows only the finely crushed plastic P2 having a long side portion of 7 mm or less to pass therethrough, and does not allow the plastic P3 having a longer side portion to pass therethrough. It has a diameter like this. Accordingly, only the finely crushed plastic P2 having a long side length of 7 mm or less passes through the hole 18a of the screen 18 and is discharged to the outside of the plastic crusher 10. At this time, since the crushed finely crushed plastic P2 has an irregular shape and may be in the shape of an elongated string, when the screen 18 having the hole 18a having a diameter of 10 mm or less is used, the finely crushed plastic P2 is dropped. If it is only due to gravity, the hole 18a may be blocked due to the impossibility of discharging. Therefore, in order to prevent such blockage of the hole 18a, a suction means (not shown) such as a blower is provided so that the finely crushed plastic P2 is sucked and forced to the outside of the plastic crusher 10. It is preferable to discharge.

  The suction means is connected to a transport pipe (not shown) that becomes a flow path when the finely crushed plastic P2 is air-carryed to the fixed quantity cutting device 30 with a plastic hopper. The suction facility 20 according to the embodiment is configured.

  In the crushing step (A) according to the present embodiment, the frictional heat between the rotary blade 15 and the fixed blade 16 rotating at high speed is obtained by finely crushing the waste plastic until the length of the long side portion becomes 7 mm or less. Thus, the waste plastic is heated together with the retained moisture, dried after being sucked by the suction means and then transported by the air current transport, and the water content in the finely crushed plastic P2 is reduced to 2.5 mass% or less almost stably. It can be. As described above, by stably setting the amount of water in the finely crushed plastic P2 to 2.5% by mass or less, the heat balance is not lost during the extrusion molding of the waste plastic molding.

(Details of extrusion molding process (B))
2ndly, based on FIG. 3, the detail of the extrusion molding process (B) which extrudes the waste plastic molding Pf using the finely crushed plastic P1 obtained as mentioned above is demonstrated. In addition, FIG. 3 is explanatory drawing which shows the structure of the screw type extrusion molding machine 50 used for the extrusion molding process (B) based on this embodiment. Further, FIG. 3 shows a pressure distribution diagram showing the state of the pressure inside the apparatus below the diagram showing the configuration of the extrusion molding machine 50.

  First, the configuration of the extrusion molding machine 50 will be described. As shown in FIG. 3, the extrusion molding machine 50 includes, for example, a substantially cylindrical main body 51, an insertion port 52 provided on one upper side of the main body 51, and a screw installed inside the main body 51. 53, a die (face plate) 54 connected to the other end of the main body 51, one or a plurality of nozzles 55 provided so as to penetrate the die 54, and a cutting installed on the tip side of the nozzle 55 Machine 56 and a cutting machine drive motor 57 for driving the cutting machine 56 are mainly provided. The extrusion molding machine 50 adds an appropriate amount of a binder to the raw material powder and extrudes a molded product obtained by granulating the raw material powder from a nozzle 55 having a predetermined diameter provided in the die 54.

  Generally as a screw type extrusion molding machine like the extrusion molding machine 50 which concerns on this embodiment, there exist a thing with a 1 axis | shaft and a 2 axis | shaft of a screw. The uniaxial one only extrudes the molded material by frictional heat, while the biaxial one includes a kneading process. FIG. 3 shows an example in which a uniaxial screw 53 is provided. Further, a predetermined gap G is provided between the front end portion of the screw 53 and the rear end portion of the die 54.

  The cutting machine 56 is not particularly limited as long as it can cut the molded product extruded from the nozzle into a predetermined length. For example, FIG. 3 shows a cutting machine drive motor 57 in the axial direction of the screw 53. The figure shows a propeller-like cutting machine that rotates on a plane perpendicular to the surface.

  Next, a method for extruding waste plastic molding using the above-described extrusion molding machine 50 will be described. In this embodiment, waste plastics containing various types of plastics are crushed as raw materials, and low melting point plastics (for example, PE, PP, etc.) in the waste plastics are melted, and the role of the binder I have it. The low melting point plastic is gradually heated and melted by pressure and frictional heat by the thrust of the screw 53 and the resistance of the die 54 (nozzle 55). On the other hand, high melting point plastics (for example, PS, PET, etc.) that are not melted here and coal that is mixed as necessary are extruded through the holes of the die 55. Between the supply of the waste plastic as the raw material and the extrusion through the hole of the die 55, that is, as shown in FIG. 3, the main body 51 has a 1: supply part, 2: a compression part, and 3: It can be divided into a crimping part, 4: a pressure equalizing part.

  1: In the supply unit, the finely crushed plastic P2 obtained in the crushing step (A) and, if necessary, the coal are fed into the extrusion molding machine 50 from the charging port 52. The finely crushed plastic P2 and coal that are input are not pressurized in almost the same state as before the input, and there is no change in material density (see arrow (1) in FIG. 3).

  Here, when coal is input as a raw material of the waste plastic molding, it is preferable to use coal having a maximum particle size of 10 mm or less and an average particle size of 1 to 3 mm. By using coal having such a particle size, the particle size distribution of the finely crushed plastic P2 and the coal is widened, so that the closest packing is possible. Therefore, it becomes a molded product having a high density when compression molding. As coal of the said particle size, what is necessary is just to use the pulverized coal as normal coal for coke ovens. In this case, the input amount of coal is 80% by mass or less with respect to the total mass of the waste plastic molded product Pf produced in this process, so that it is possible to perform the closest packing in powder engineering in a cold state. A particle size distribution (Furnas distribution) can be employed. That is, the finely crushed plastic P2 has a long side portion of 7 mm or less, and its shape is indefinite, and can be various shapes such as a spherical shape, a lump shape, and an elongated string shape. Since the particle size is 10 mm or less and the average particle size is 1 to 3 mm, and the shape is various such as a spherical shape and a lump shape, it is compressed by widening the particle size distribution of the raw material powder when mixing them. In this case, a molded product having a high density can be formed.

  Moreover, as coal input at this process, it is preferable to use a water content of 2.5 mass% or less. As a result, the heat balance is not lost during the extrusion molding of the waste plastic molding Pf.

  Thus, when coal is added as a raw material for the waste plastic molding Pf, it is necessary to knead the finely crushed plastic P2 and coal. It is preferred to use an extruder with a screw.

  2: In the compression section, the finely crushed plastic P2 (and coal), which is the input raw material, is compressed and pressurized. This compression / pressurization also partially has a degassing action of the raw material (see arrow (2) in FIG. 3).

  3: In the crimping part, the raw material is further pressurized to increase the density, and according to the back pressure of the die 54, the raw material having a sufficiently increased density is sent to “4: pressure equalizing part” described later (see FIG. 3 arrows (see 2)).

  4: In the pressure equalizing section, the back force generated in “3: crimping section” is evenly distributed on the surface of the die 54 due to the shape of the screw 53 and the like, and the flow of the raw material is made uniform. The pressure is immediately averaged over the cross section of the main body 51 and the time. At this stage, the inside of the extrusion molding machine 50 is heated to about 150 to 200 ° C. As a result, the low melting point plastics such as PE and PP in the finely crushed plastic P2 start to melt and liquefy. Here, the heating temperature in the extrusion molding machine 50 is set to 150 to 200 ° C. When the temperature is less than 150 ° C., there is almost no component of the plastic to be melted. This is because if the temperature exceeds 200 ° C., there is a risk that chlorine is vaporized from the chlorine-containing plastic and dioxins are generated.

  In addition, the quality of the waste plastic molding is greatly influenced by the proportion of the molten plastic that serves as a binder. Specifically, it is preferable that the ratio of the component melted at 150 to 200 ° C. among the components contained in the waste plastic is 20 to 60% by mass with respect to the total mass of the waste plastic molded product Pf. Thus, in a hot state heated at 150 ° C. to 200 ° C., 20% by mass or more of the plastic component is melted with respect to the total mass of the waste plastic molding Pf, so that the coal and the melting point are over 200 ° C. It plays the role of a binder that binds to a plastic component that does not melt, reduces voids in the waste plastic molding, and can produce a waste plastic molding Pf having a larger apparent density. Moreover, it is special by adjusting so that the component which melt | dissolves at 150 to 200 degreeC among the components contained in waste plastic may contain the quantity of 20 mass% or more with respect to the total mass of a waste plastic molding. Without using expensive equipment, the load can be reduced by using an ordinary screw type extruder, and the repair frequency can be reduced.

  The mixing ratio of each plastic component of the waste plastic generated from household waste is about 20% by mass for the waste plastic having a melting point of 150 ° C. and about 60% by mass for the waste plastic having a melting point of 200 ° C.

  In addition, when waste plastic having a large amount of plastic component that melts at 150 to 200 ° C. is used, by reducing the distance G between the die 54 and the screw 53, excessive melting due to an increase in kneading time can be achieved. Can be prevented. When it is excessively melted, the indentation pressure is not applied and the compaction is poor, so that the apparent density of the molded product is lowered.

  Next, in “5: Die portion” in the nozzle 55 of the die 54, the pressure drops from the pressure of the back surface portion (surface on the screw 53 side) to the atmospheric pressure. This pressure drop varies depending on the opening ratio of the die 54, the shape and length of the die 54, the raw material passing speed, the physical properties of the raw material, and the like. Further, the resistance (back pressure) of the die 54 increases as the hole area ratio decreases or the length of the die 54 (nozzle 55) increases, and the pressure of “4: pressure equalizing portion” increases (FIG. 3 (see part (3)).

  Finally, the waste plastic molding Pf extruded from the nozzle 55 is cut into a length of 100 mm or less, preferably 35 mm or more by a cutting machine 56 (see (4) in FIG. 3). Moreover, in this embodiment, since the diameter of the nozzle 55 is set to 35 to 100 mm, the diameter of the extruded waste plastic molding Pf is also about 35 to 100 mm. As described above, the size of the waste plastic molded product Pf is set to a maximum length of 100 mm or less because the width of the coke oven is 440 to 460 mm, and the turntable is cut out from the charging vehicle. This is because a lump of about 100 mm or less is considered to be the limit because the method is used.

As described above, a cylindrical waste plastic molding Pf having a specific surface area of 180 mm ² / g or less can be obtained. The specific surface area of 180 mm ² / g or less is based on the examination results described below. On the other hand, the lower limit of the specific surface area is preferably 50 mm ² / g or more in view of the processing efficiency of the waste plastic by adding the waste plastic molding Pf.

Here, as the reason why the specific surface area is set to 180 mm ² / g or less, the relationship between the specific surface area and the reduction cost of the coke strength index will be described based on FIGS. FIGS. 4 to 6 are graphs showing the relationship between the specific surface area and the coke strength index. Examples of cases where the amount of waste plastic molding added is 2 mass%, 3 mass%, and 5 mass%, respectively. It is.

Up to 1% by weight of the waste plastic molding, the cost of reducing the coke strength index is zero for any waste plastic molding, but as shown in FIG. When the surface area is 180 mm ² / g or more, the strength is clearly reduced by ▲ 1.0. When the specific surface area is 180 mm ² / g or less, the allowance for reducing the coke strength index is zero. Further, as shown in FIG. 5, even when 3% by mass of the waste plastic molding is added, the specific surface area is about 180 mm ² / g, and the decrease in the coke strength index is about 0.5, and below this, It is possible to suppress the reduction cost of the coke strength index to about zero. Furthermore, as shown in FIG. 6, even when 5% by mass of the waste plastic molding is added, the specific surface area is about 180 mm ² / g and the coke strength index decreases by about ▲ 4, which is the lowest level practically usable. Is maintained. Further, if the specific surface area is set to 100 mm ² / g or less, the cost of reducing the coke strength index can be reduced to about 0.5.

(Details of coke production process (C))
Third, the details of the coke production process (C) for producing coke in a coke oven using the waste plastic molding Pf obtained as described above will be described.

Instead of a part of the coke oven coal, the waste plastic molding Pf obtained by the extrusion molding step (B) is charged into the coke oven together with the coke oven coal to produce coke. At this time, in this embodiment, the specific surface area of the waste plastic molding Pf is 180 mm ² / g or less, so that the contact area between the waste plastic and coal can be reduced. Inhibiting the caking property of can be remarkably suppressed. Specifically, as shown in the examples described later, according to the method for producing coke according to the present embodiment, the waste plastic molding is added to the entire raw material of the coal and waste plastic molding to be put into the coke oven. It was found that even when charged to 1% by mass to 5% by mass, the reduction in coke strength can be suppressed.

  In addition, according to the method for producing coke according to the present embodiment, the waste plastic can be produced regardless of what kind of plastic is contained in any proportion, or what kind of moisture is contained. By reducing the contact area with coal, that is, by reducing the specific surface area of the waste plastic molding, the reduction in coke strength can be significantly suppressed. Furthermore, the coke manufacturing method according to the present embodiment has a great effect such that the equipment cost and the continued repair cost can be reduced without purchasing a special and expensive molding machine.

  Hereinafter, the present invention will be described more specifically with reference to Examples and Comparative Examples of the present invention.

  The types of waste plastics, the ratio of each and the moisture content are those that have changed greatly over the long-term operation of one week. Coal used is one that has changed variously over a long period of operation in one week, and DI (Drum Index), which is rotational strength, is used as the coke strength index for dry distillation (JIS M 8801). Based on the coke strength index produced without adding waste plastic moldings to coal, 2%, 3%, and 5% by weight of waste plastic moldings for one week at each waste plastic molding facility It is shown using the average value of the properties produced by long-term operation. Table 1 shows the properties of the molded product, Table 2 shows the properties of the finely crushed plastic used for the production of the molded product, and Table 3 shows the properties of the coal used for the production of the molded product.

  In comparison between Invention Example 1 and Invention Example 2, the size of the molded product is the same, but the apparent density is increased due to the difference in coal content, and the specific surface area is decreased in Invention Example 2. Comparison between Invention Example 2 and Invention Example 3 shows that increasing the apparent density to 0.9 kg / liter and increasing the size of the molded product have almost the same effect on specific surface area. In comparison between Invention Example 3 and Invention Example 4, it can be seen that the specific surface area is lowered by increasing the size of the molded product with a constant apparent density. In the present invention, the specific surface area can be reduced to Example 8 of the present invention.

  The comparative example 1 is the average value of the characteristic manufactured by patent document 1 and the comparative example 2 by the long-term operation of the waste plastic molding for 1 week. In these two materials, the specific surface area and the apparent density of the waste plastic molding were increased beyond the upper limit of the present invention by increasing the maximum length of the finely crushed plastic beyond the upper limit of the present invention.

This example of the present invention makes it possible to obtain a waste plastic molding having a specific surface area of 180 mm ² / g or less as described above, so even if it is mixed with coal and put in a coke oven at 2% by mass or more. As can be seen from FIGS. 4 to 6 described above, it is possible to manufacture coke for metallurgy with good quality compared to the comparative example.

  As mentioned above, although preferred embodiment of this invention was described referring an accompanying drawing, it cannot be overemphasized that this invention is not limited to this example. It will be apparent to those skilled in the art that various changes and modifications can be made within the scope of the claims, and these are naturally within the technical scope of the present invention. Understood.

It is explanatory drawing which shows roughly an example of the manufacturing equipment of the waste plastic molding used for the manufacturing method of the coke which concerns on one Embodiment of this invention. It is explanatory drawing which shows the structure of the crusher for plastics used for the crushing process which concerns on the embodiment. It is explanatory drawing which shows the structure of the screw type extrusion molding machine used for the extrusion molding process which concerns on the same embodiment. It is a graph which shows the relationship between the specific surface area and coke strength index | exponent which concern on one Example of this invention, and is an example at the time of setting the addition amount of a waste plastic molding to 2 mass%. It is a graph which shows the relationship between the specific surface area and coke strength index | exponent which concern on one Example of this invention, and is an example at the time of setting the addition amount of a waste plastic molding to 3 mass%. It is a graph which shows the relationship between the specific surface area and coke strength index | exponent which concern on one Example of this invention, and is an example at the time of setting the addition amount of a waste plastic molding to 5 mass%.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Plastic crusher 12 Hopper 14 Crushing rotor 15 Rotating blade 16 Fixed blade 18 Screen 20 Suction equipment 30 Fixed amount cutting device with plastic hopper 40 Fixed amount cutting device with coal hopper 50 Extruder 51 Main part 52 Input port 53 Screw 54 Die 55 Nozzle 56 Cutting machine 57 Cutting machine drive motor P1 Rough crushing plastic P2 Fine crushing plastic Pf Waste plastic molding

Claims (7)

Crushing waste plastic into finely crushed plastic with a maximum length of 7mm or less
The finely crushed plastic is extruded while being heated and melted in an extrusion molding machine to obtain a lump waste plastic molding having a maximum length of 100 mm or less and a specific surface area of 180 mm ² / g or less,
A method for producing coke for metallurgy using a waste plastic molding, wherein the waste plastic molding and coal are charged into a coke oven to produce coke.   2. The method for producing coke for metallurgy using the waste plastic molding according to claim 1, wherein an average length of the long side portion of the finely crushed plastic is 2 to 5 mm.   The method for producing coke for metallurgy using the waste plastic molding according to claim 1 or 2, wherein the finely crushed plastic has a water content of 2.5 mass% or less.   The content of the low-temperature melting waste plastic having a component that melts at 150 ° C. to 200 ° C. among the components contained in the waste plastic is 20 to 60% by mass with respect to the total mass of the waste plastic molding. The manufacturing method of the coke for metallurgy using the waste plastic molding of any one of Claims 1-3 characterized by the above-mentioned.   The waste according to any one of claims 1 to 4, wherein coal having a maximum particle size of 10 mm or less and an average particle size of 1 to 3 mm is mixed with the finely crushed plastic in the extruder. A method of manufacturing coke for metallurgy using plastic moldings.   The mass of coal mixed with the finely crushed plastic is 80% by mass or less with respect to the total mass of the waste plastic molded product, and the treatment using the waste plastic molded product according to claim 5, Method for producing gold coke.   The method for producing coke for metallurgy using waste plastic molding according to claim 5 or 6, wherein the coal to be mixed has a water content of 2.5 mass% or less.

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