Recycling method and recycling system

Abstract

To produce high-quality resin pellets. The method includes: a cutting step of cutting the net, rope, string, or cord into small pieces; a washing step of washing the small pieces; a dehydration step of dehydrating the small pieces after washing in the washing step; a drying step of drying the small pieces after dehydration; a grinding step of grinding the dried pieces into smaller pieces; a molding step of processing the micro-pieces into pellet shape by extrusion molding; Recycling methods including:

Description

Technical Field

[0001] The present invention relates to a recycling method and a recycling system.

Background Art

[0002] In the above technical field, Patent Document 1 discloses a technique of pulverizing fishing net wire, washing it, dehydrating and extruding it, and then melt granulating it.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in the technique described in the above document, nylon wire is used as a material, and fibers with a maximum length of 3 cm to 5 cm are put into an extruder for melt granulation. Therefore, high-quality pellets could not be produced.

[0005] An object of the present invention is to provide a technique for solving the above problems.

Means for Solving the Problems

[0006] To achieve the above object, the method according to the present invention includes Used for rigging and discarded a cutting step of cutting a net, rope, string or cord into small pieces, a washing step of washing the small pieces, a dehydrating step of dehydrating the small pieces after washing in the washing step, a drying step of drying the dehydrated small pieces, a pulverizing step of further pulverizing the dried small pieces into even smaller micro pieces, A forming step of processing the micro pieces into a pellet shape by extrusion molding; It is a recycling method including.

[0007] To achieve the above object, the system according to the present invention Used for rigging and discarded A cutting device for cutting a net, rope, string or cord into small pieces; A cleaning device for cleaning the cut small pieces; A dehydration device for dehydrating the small pieces after being cleaned by the cleaning device; A drying device for drying the dehydrated small pieces; A crushing device for further crushing the dried small pieces into micro pieces; A forming device for processing the micro pieces into a pellet shape by extrusion molding; It is a recycling system provided with.

Effect of the Invention

[0008] According to the present invention, high-quality resin pellets can be manufactured.

Brief Description of the Drawings

[0009]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Mode for Carrying Out the Invention

[0010] Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the drawings. However, the components described in the following embodiments are merely examples, and are not intended to limit the technical scope of the present invention thereto.

[0011] [First Embodiment] The fishing net recycling system 100 as the first embodiment of the present invention will be described with reference to FIG. 1.

[0012] As shown in FIG. 1, the fishing net recycling system 100 includes a cutting device 101, a cleaning device 102, a dewatering device 103, a drying device 104, a pulverizing device 105, and an extrusion molding device 106.

[0013] Generally, even a small fishing net has a width of 2 m to 6 m and a length of about 150 m to 200 m. When it comes to a fishing net for a fixed net, it reaches a size with a width of 70 m and a length of about 300 m. For such fishing nets, currently, the proportion in marine waste is very high, and properly recycling them has become a very important social demand.

[0014] Therefore, in the fishing net recycling system 100, first, in the cutting device 101, the fishing net 110 is cut into fishing net pieces 120 of about 20 to 50 mm. The cutting device 101 is equipped with a mechanism like a large shredder, and a rotor with a diameter of about 300 mm provided with a plurality of blades on the surface rotates to cut the fishing net into small pieces to generate the fishing net pieces 120.

[0015] The cleaning device 102 peels off the dirt and the adhered scale (substances deposited, adhered, and fixed due to the precipitation of minerals and the like contained in seawater) 121 adhered to the fishing net pieces 120 placed on the mesh conveyor by water pressure, and washes them away by the water flow.

[0016] FIG. 2 is a diagram showing an example of the cleaning device 102. The fishing net piece 120 is placed on a conveyor 201 using a 500-mm-wide SUS mesh belt, and while being conveyed at a speed of about 2.0 m / min, water with a water pressure of 2.0 MPa is continuously sprayed onto the fishing net piece 120 using a high-pressure washer 202 installed above the conveyor 201. Since the length of the cleaning process is about 5,000 mm, high-pressure cleaning water is sprayed onto the fishing net piece 120 for about 2 minutes and 30 seconds in terms of time, washing away the dirt and scale adhering to the fishing net piece 120 while peeling them off. Note that the amount of water for washing away dirt and scale is about 20 L to 50 L per minute per 1 kg of the fishing net. The fishing net piece 120 is preferably stacked to a thickness of 50 mm or less, and the high-pressure washer 202 is preferably installed at a distance of 40 mm or less from the surface of the fishing net piece 120.

[0017] According to such a cleaning method, as shown in FIG. 3, scale dirt 301 adhering to the knots of wires and the like, which cannot be removed by water washing in a general water tank, can be peeled off by the physical force of water pressure, and dirt such as salt and peeled impurities can be washed away by the cleaning water flow. Also, compared with the method using a surfactant or the like, there is an effect of being environmentally friendly.

[0018] Returning to FIG. 1, after cleaning with the cleaning device 102, the moisture 130 remaining on the fishing net piece 120 is removed using a dehydrating device 103 and a drying device 104. In the dehydrating device 103, it is preferable to dehydrate the fishing net piece so that the moisture content becomes 10% or less by centrifugal dehydration or air blow dehydration. In the drying device 104, it is preferable to dry the fishing net piece using a dryer such as a hot air type or a far-infrared type so that the moisture content becomes 5% or less.

[0019] Next, using the pulverizing device 105, the dried fishing net pieces 120 are pulverized into fiber pieces 150 with a size of 10 mm or less. In order to ensure stable processing in the extrusion process (pellet processing) in the extrusion molding device 106, it is necessary to supply the processing material in a fixed quantity. Generally, for raw materials with good handleability such as pellets and powder raw materials, supply devices such as tanks with screw feeders or tanks with agitators are used to supply the material in a fixed quantity. However, mainly due to shape problems (film / fluff shape, cloth pieces, cotton / yarn shape, etc.), there are cases where the above-mentioned supply device cannot discharge / supply the raw material quantitatively. When processing such materials, it is mainstream in repellet processing to use a cutter compactor (https: / / www.fareastnetwork.co.jp / theme71.html).

[0020] However, this cutter compactor method is not universal either. In the case of a very low-bulk filamentous material, the material floats inside the cutter compactor, so sufficient pulverization and volume reduction cannot be achieved, and the material still cannot be supplied quantitatively to the extruder.

[0021] Therefore, the material is pulverized into a shape that can be handled by a general supply device. Specifically, the fishing net pieces that have undergone washing, dehydration, and drying treatments are pulverized into fiber pieces with a size of 10 mm or less using a shear-type single-shaft crusher. By pulverizing to 10 mm or less, the strong entanglement (blocking) between the materials disappears, and it has a handleability close to that of pellets. As a result, quantitative supply to the extrusion molding device 106 can be achieved.

[0022] In the extrusion molding system 106, pressure and heat are applied to the fiber pieces 150 by a single-screw extruder to perform semi-melting molding and generate pellets 160.

[0023] Figure 4 is a diagram showing the configuration of the extrusion molding system 106. The belt conveyor 401 is a conveyor that conveys and supplies the pulverized fishing net to the cutter compactor 403. The metal detector 402 is a device that detects metal pieces (foreign substances) contained in the pulverized fishing net.

[0024] The cutter compactor 403 is a rotary grinder with a rotary blade installed at the bottom part, and in order to ensure stable extrusion processing, it simultaneously dries and reduces the volume of the shredded fishing net.

[0025] (Drying) When the material contains moisture during extrusion processing (heating to melt the resin), the moisture vaporizes, causing processing defects (strand breakage) or poor quality of processed pellets (foamed pellets, deterioration of basic physical properties, etc.). Therefore, the extrusion machine part is provided with vents (degassing ports) for venting water vapor and other gases, and degassing is performed from the melted resin by natural opening or forced intake by a vacuum pump. However, when the moisture content is about 5%, degassing cannot be sufficiently performed only by the degassing method from the vents. Therefore, in order to further reduce the moisture content before feeding into the extruder, preliminary drying of the material is performed by the shearing heat generated by grinding with the cutter compactor 403 and the frictional heat between the material and the inner wall.

[0026] (Volume reduction) During extrusion processing, the material is melt-processed while being conveyed by a screw. Therefore, if the bulk specific gravity of the material before processing is low, the resin discharge amount (production amount) of the extrusion processing will not increase. Therefore, the material is semi-melted by the shearing heat generated by grinding with the cutter compactor 403 and the frictional heat between the material and the inner wall, and the bulk specific gravity of the material is increased.

[0027] The main extruder 404 heats and melts the material that has been preliminarily dried and volume-reduced by the cutter compactor 403 while conveying it with a screw, and at the same time, degassing operations are performed at the vents and the connecting and opening parts between the main extruder 404 and the sub-extruder 405. The material melted by the main extruder 404 is once taken out of the machine and then put into the sub-extruder 405 again to promote degassing.

[0028] The sub-extruder 405 extrudes the melted and degassed material into strands of about Φ1 to 3 mm. The cooling water tank 406 immerses the material extruded in strands in water for cooling and solidification.

[0029] The water drainage device 407 removes the moisture adhering to the material surface by means of air blowing or the like. The pellet cutter 408 cuts the strand-shaped material into lengths of about 1 to 3 mm. Further, the vibrating sieve 409 removes defective molded products (such as those with a small diameter or those that could not be cut by the pellet cut).

[0030] The blower 410 is a device that pneumatically conveys pellets to the pellet tank 411. The pellet tank 411 is a temporary storage tank for the pellets conveyed by pneumatic conveyance.

[0031] Figure 5 is a flowchart for explaining the processing flow using the above-mentioned fishing net recycling system 100. In step S501, the fishing net is cut into fishing net pieces of about 20 to 50 mm. Next, in step S503, while conveying the cut fishing net pieces by a conveyor, high-pressure washing water is sprayed. Water is sprayed from a distance of about 30 to 40 mm from the fishing net pieces at a water pressure of 2.0 MPa to peel and wash off the adhered dirt, and the adhered dirt and the peeled-off dirt are washed away with water at a water volume of about 20 to 50 L / min per 1 kg of the material.

[0032] Next, in step S505, dehydration is performed so that the moisture content becomes 10% or less, and in step S507, drying is performed so that the moisture content becomes 5% or less.

[0033] Next, in step S509, the material is pulverized into a size (about 10 mm) that can be quantitatively supplied to the extruder.

[0034] Finally, in step S511, it is processed into a pellet shape by a single-screw extruder.

[0035] Through the above system and processing, very high-quality pellets can be produced from waste fishing nets, and environmental problems and energy problems can be solved more actively.

[0036] [Other Embodiments] Although the present invention has been described with reference to the embodiments, the present invention is not limited to the above embodiments. Various changes that can be understood by those skilled in the art can be made to the configuration and details of the present invention within the technical scope of the present invention. In addition, a system or device in which the separate features included in each embodiment are combined in any manner is also included in the technical scope of the present invention.

Claims

1. A recycling method comprising a cutting step of cutting a net, rope, string or cord that has been used for ship equipment and discarded into small pieces; a washing step of washing the small pieces; a dehydrating step of dehydrating the small pieces after washing in the washing step; a drying step of drying the dehydrated small pieces; a pulverizing step of pulverizing the dried small pieces into even smaller micro-pieces; a molding step of processing the micro-pieces into a pellet shape by extrusion molding.

2. The recycling method according to Claim 1, wherein in the washing step, water is sprayed at a rate of 20 to 50 L per minute per 1 kg of the small pieces at a water pressure of 2.0 MPa or more for washing.

3. The recycling method according to Claim 1 or 2, wherein in the dehydrating step, the small pieces are dehydrated so that the moisture content becomes 10% or less.

4. The recycling method according to Claim 1 or 2, wherein in the drying step, the small pieces are dried so that the moisture content becomes 5% or less.

5. A recycling system comprising a cutting device for cutting a net, rope, string or cord that has been used for ship equipment and discarded into small pieces; a washing device for washing the cut small pieces; a dehydrating device for dehydrating the small pieces after washing by the washing device; a drying device for drying the dehydrated small pieces; a pulverizing device for pulverizing the dried small pieces into even smaller micro-pieces; a molding device for processing the micro-pieces into a pellet shape by extrusion molding. ​

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