KR20230036583A - Disposal system for waste plastic and disposal method thereof - Google Patents

Abstract

The present invention relates to a waste plastic treatment system including: a detection device for detecting foreign substances contained in waste plastics; a laser device for thermally expanding or contracting at least one of a polymer and foreign substances contained in the waste plastics by irradiating a laser beam onto an area containing the foreign substances detected by the detection device; and a jig for fixing and removing the foreign substances that are thermally expanded or contracted by the laser beam and are separated from the polymer.

Description

Waste plastic processing system and its processing method {DISPOSAL SYSTEM FOR WASTE PLASTIC AND DISPOSAL METHOD THEREOF}

The present invention relates to a waste plastic treatment system and a treatment method thereof. Specifically, the present invention relates to a waste plastic treatment system and method for removing foreign substances by using a difference in coefficient of thermal expansion between a polymer contained in waste plastic and foreign substances.

In general, when recycled plastic waste is received at a collection point for recycling, these recycled plastic wastes have greatly different characteristics such as flame retardancy and non-flammability, and various materials are mixed in each of flame retardancy and non-flammability. In terms of color, white, Recycled plastic waste in different colors, such as black and red, is received in a mixed state.

In the conventional process of recycling plastics, waste plastics are processed into pieces and powders through crushing, crushing, and sorting steps after collection so that waste plastics can be used as raw materials. Then, in the process of recycling conventional plastics, recycled plastics from which foreign substances are removed can be produced by dissolving processed waste plastics in a solvent and recovering polymers.

However, in the conventional process of recycling plastics, if foreign substances are not completely dissolved in a solvent, foreign substances may be included in the recovered recycled plastic, resulting in a decrease in value as a raw material.

Therefore, the quality of the raw material of the recycled plastic using the waste plastic is degraded.

Korean Patent Publication No. 10-2011-0021781

The present invention is to solve the problems of the prior art, and to provide a waste plastic processing system and method for removing the foreign matter by detecting the foreign matter and irradiating a laser to an area containing the foreign matter to thermally expand or contract the foreign matter.

One embodiment of the present invention is a detection device for detecting foreign substances contained in waste plastic; a laser device for thermally expanding or contracting at least one of a polymer and foreign matter contained in the waste plastic by irradiating a laser onto an area containing the foreign matter detected by the sensing device; and a jig for fixing and removing the foreign matter that is thermally expanded or contracted by the laser and has a gap between the polymer and the polymer.

In one embodiment of the present invention, there is provided a waste plastic treatment system further comprising a control unit for controlling the laser device so that the laser is irradiated only to an area containing the foreign matter detected by the detection device.

In another embodiment of the present invention, in the waste plastic processing method including crushing, crushing, and sorting, laser irradiation is applied to a region containing foreign substances in the waste plastic to thermally expand or contract the foreign substances. and a foreign matter separation step of fixing the thermally expanded or thermally contracted foreign matter with a jig to separate it from a polymer contained in the waste plastic.

According to the waste plastic processing system and method according to the exemplary embodiments of the present invention, the present invention detects a foreign material and irradiates a laser to an area containing the foreign material to thermally expand or contract the foreign material to polymer and foreign matter contained in the waste plastic. It is possible to remove foreign substances by forming a gap between them.

1 is a diagram showing a conventional wastewater treatment process.
2 is a block diagram showing a waste plastic treatment system according to an exemplary embodiment of the present invention.
3 is a schematic diagram showing the principle of a laser device and a jig according to an exemplary embodiment of the present invention.
4 is a flowchart illustrating a waste plastic treatment method according to an exemplary embodiment of the present invention.

Hereinafter, the present invention will be described in detail with reference to the drawings. However, the drawings are for illustrating the present invention, and the scope of the present invention is not limited by the drawings.

2 is a schematic diagram showing a waste plastic treatment system 100 according to an exemplary embodiment of the present invention.

The waste plastic processing system 100 may include a sensing device 10 , a laser device 20 and a jig 30 .

The detection device 10 may detect foreign substances included in the waste plastic. Waste plastics may contain polymers and foreign substances. Here, the polymer is High Density Polyethylene (HDPE), Low Density Polyethylene (LDPE), Polyethylene terephthalate PET, Polystyrene (PS), Polypropylene (PP), Polychloride It may include any one of vinyl (Poly Vinyl Chloride, PVC). Also, the foreign material may include at least one of urethane and polystyrene.

In addition, the waste plastic supplied to the sensing device 10 may be supplied in any one of a complete form after collection, a piece form, and a powder form.

The detection device 10 may irradiate a light source to the waste plastic and monitor the presence or absence of foreign matter through reflected light.

The detection device 10 detects foreign substances included in the waste plastic, and may include, for example, an optical device.

In one embodiment, the sensing device 10 may include a sensor unit (not shown) and a recognition unit (not shown).

The sensing device 10 according to an embodiment may include an RGB camera as a sensor unit. The RGB camera can take images along the length and width directions of waste plastic. The RGB camera can extract image data after taking an image of the entire waste plastic.

The recognition unit stores RGB color codes corresponding to polymers and foreign substances, and can recognize the location and amount of foreign substances in waste plastic using the pre-stored RGB color codes based on the image data extracted by the RGB camera. there is.

For example, the RGB color codes of the polymer stored in the recognition unit may be R-255, G-255, and B-255 (R=Red, G=Green, B=Black).

In another embodiment, the detection device 10 may irradiate the waste plastic with light and detect the foreign material using the reflected light.

The sensing device 10 may include a light source (not shown), a sensor unit (not shown), and a foreign object detection unit (not shown).

The light source may irradiate light to the waste plastic. The light source may use a laser, point light, or optical fiber, and the light emitted from the light source may include LED, infrared, or ultraviolet light.

The light source may radiate light in a straight line with the waste plastic surface without inclination, or may radiate light to have a predetermined angle of incidence with the waste plastic surface. That is, light emitted from the light source may have an incident angle of 10° to 90°.

The waste plastic treatment system 100 according to the present invention may further include a moving unit (not shown) for moving the waste plastic.

In addition, one or more light sources may be provided in a direction perpendicular to the direction in which the waste plastic moves. That is, if the direction in which the moving unit moves the waste plastic is the x-axis direction, the light sources may be aligned in the z-axis direction. Therefore, the light source can irradiate light to all surfaces of the width (z) and length (x) of the waste plastic.

The sensor unit may detect reflected light reflected from the waste plastic. The sensor unit may be configured using various light detection sensors without limitation, but, for example, the sensor unit may include a camera. Accordingly, the sensor unit may image the composition included in the waste plastic based on the detected reflected light, and the foreign material detection unit to be described below may analyze the image to determine the size, shape, location, and the like of the foreign material.

In the sensing device 10 according to the present invention, since the light source is positioned in a line or line form, the sensor unit may also be arranged in a line or line form. That is, one or more sensor units may be included and positioned in a direction perpendicular to the moving direction of the waste plastic. For example, the sensing unit may be provided in a form elongated in the direction of the width (z) of the waste plastic, or a plurality of sensor units may be arranged in a row in the direction of the width (z) of the waste plastic.

And, the sensor unit may be provided at a symmetrical position with respect to the light source. The sensor units located or arranged in a line shape may be provided respectively in a moving direction of the waste plastic and in a direction opposite to the moving direction based on the light source.

The foreign matter detection unit may detect the presence and location of foreign matter in the waste plastic through reflected light detected through the sensor unit.

For example, when a polymer is placed on the surface of a foreign substance in a part of waste plastic, the foreign matter detection unit is formed by the image formed on the surface reflection light reflected from the top surface of the waste plastic and the first internal reflection light refracted once inside the waste plastic. By comparing the images, it can be determined that the material located on the surface and inside of the waste plastic is different.

In addition, the foreign matter detection unit may analyze the type of composition located on the surface and inside of the waste plastic by analyzing the refraction angle of the reflected light reflected from the surface of the waste plastic and the internally reflected light. That is, the foreign matter detection unit may determine that a polymer is located on the surface of the waste plastic and a foreign material is located therein, based on the refraction angle of the reflected light measured by the sensor unit.

3 is a schematic diagram showing the principle of a laser device 20 and a jig 30 according to an exemplary embodiment of the present invention.

Foreign substances included in waste plastics can increase or decrease in volume when the temperature is increased by receiving heat. Accordingly, the laser device 20 may thermally expand or contract at least one of the polymer and the foreign material by radiating a laser beam to an area including the foreign material detected by the sensing device 10 .

For example, waste plastics may include polyvinyl chloride (PVC) as a polymer. In addition, the waste plastic may include polystyrene and urethane as foreign substances, and in this case, the urethane may include polyurethane.

The thermal expansion coefficient of polyvinyl chloride is 50.4×10 ^-6 m/mk, polystyrene is 70×10 ^-6 m/mk, and polyurethane is 57.6×10 ^-6 m/mk.

That is, the laser device 20 can thermally expand the polymer and the foreign material, and the adhesive strength between the polymer and the foreign material may be weakened as stress is induced by the difference in thermal expansion coefficient between the polymer and the foreign material in the waste plastic.

The laser device 20 is not limited as long as it can apply heat to foreign substances, but for example, the laser device 20 may include an infrared laser (IR Laser) or a carbon dioxide gas laser.

Polymers and foreign substances contained in waste plastics can be separated as the stress caused by the difference in thermal expansion coefficient exceeds the interfacial adhesive force. As a result, a gap may be formed between the polymer and the foreign material.

The laser device 20 may have a wavelength of 350 nm to 10400 nm, preferably a wavelength of 1064 nm to 9800 nm.

When the laser device 20 is an infrared laser, the laser device 20 may have a wavelength of 1064 nm to 9800 nm. And, when the laser device 20 is a carbon dioxide gas laser, it may have a wavelength of 9800 nm to 10400 nm.

If the wavelength of the laser irradiated from the laser device 20 is less than 350 nm, the wavelength of the laser irradiated from the laser device 20 is shortened, so that the waste plastic is excessively heated, and the waste plastic is vaporized to generate toxic gas. there is.

In addition, when the wavelength of the laser exceeds 10400 nm, the wavelength of the laser becomes longer, the energy density is lowered, and a problem in that the foreign material does not thermally expand or contract may occur.

The jig 30 can be thermally expanded or thermally contracted by a laser to fix and remove polymers included in the waste plastic and foreign substances in gaps. The jig 30 is not particularly limited as long as it can fix foreign substances, but may include, for example, a pair of pressurizing modules in the form of tongs and spaced apart from each other by a predetermined distance.

In addition, the waste plastic treatment system 100 according to the present invention may further include a controller 40 capable of controlling the laser device 20 and the jig 30 .

The laser device 20 may extend in the width (z) or length (x) direction of the waste plastic, or may move in any one or more directions of the width (z) and length (x) directions of the waste plastic. Also, the jig 30 may move in any one or more directions of the width (z) and length (x) directions of the waste plastic.

The controller 40 may control the laser device 30 and the jig 30 based on data detected, measured, and analyzed by the sensing device 10 .

For example, when the detection device 10 detects a region containing foreign substances in waste plastic, the controller 40 may move the laser device 30 and the jig 30 to the region. In addition, the control unit 40 may irradiate the laser beam only to the region by controlling the laser irradiation direction of the laser device 30 and the number of laser beams to irradiate the laser beam in order to thermally expand the foreign matter included in the region. When a gap occurs between the polymer and the foreign substance contained in the waste plastic, the controller 40 fixes the jig 30 to the foreign substance and moves the jig 30 in the direction opposite to the position of the polymer to physically remove the foreign substance from the polymer and the foreign substance. can be separated.

The waste plastic treatment system 100 according to the present invention may further include a pre-processing unit (not shown). The pre-processing unit pre-processes the waste plastic before supplying it to the sensing device 10, and may perform any one or more of crushing, crushing, and sorting of the waste plastic.

The pre-processing unit can crush the collected waste plastic and cut it into small pieces. The pre-processing unit can be cut to crush the waste plastic in the form of pieces into smaller sizes. The pre-processing unit can crush waste plastic into a size of 5 mm to 15 mm. Also, the preprocessing unit may classify and select pieces whose sizes do not fall within the range of 5 mm to 15 mm among the crushed and pulverized plastic pieces.

4 is a flowchart illustrating a waste plastic treatment method according to an exemplary embodiment of the present invention.

The waste plastic treatment method may largely include a crushing step (S10), a crushing step (S20), and a sorting step (S30). And, in any one of the order of the front of the crushing step (S10), between the crushing step (S10) and the crushing step (S20), and between the crushing step (S20) and the sorting step (S30), the foreign matter detection step (S1), the laser irradiation step (S2) and foreign matter separation step (S3) may be performed.

In the crushing step (S10), the collected waste plastic may be cut into small pieces using a crushing device. In the crushing step (S20), the waste plastic in the form of pieces after the crushing step (S10) may be crushed into a smaller size. In the crushing step (S20), the waste plastic may be crushed into a size of 5 mm to 15 mm. In the sorting step (S30), among the crushed and pulverized plastic pieces, pieces whose size does not fall within the range of 5 mm to 15 mm may be classified.

Foreign matter detection step (S1)

In the foreign matter detection step ( S1 ) according to an exemplary embodiment of the present invention, an area containing the foreign matter may be detected by scanning the waste plastic.

In the foreign matter detection step (S1), a composition for each location of the waste plastic may be provided as an image based on the reflected light reflected by irradiating light onto the surface of the waste plastic. In the foreign matter detection step (S1), the entire waste plastic is photographed using an RGB camera and the location containing the foreign matter is recognized through the color difference of the image provided, or the waste plastic is detected at an angle relative to the incident angle of light. It can detect the location of foreign substances contained in plastic. Therefore, in the foreign matter detecting step (S1), the position where the foreign matter is included in the waste plastic may be detected and the area occupied by the foreign matter in the waste plastic may be calculated.

In the foreign matter detection step (S1), the collected waste plastic may be scanned in any one of a complete form, a piece form, and a powder form.

Laser irradiation step (S2)

In the laser irradiation step (S2), at least one of the polymer and the foreign substance may be thermally expanded or contracted by irradiating a laser to the waste plastic region containing the foreign substance detected by the foreign matter detection step (S1).

Polymers and foreign substances included in waste plastic have different coefficients of thermal expansion, and thus, a difference may occur in the expansion volume of the polymer and foreign substances.

In addition, two or more foreign substances included in the waste plastic may be included. Compositions included in the foreign material have different coefficients of thermal expansion, and thus, a difference may occur in the expansion volume of the foreign material.

In the laser irradiation step (S2), a gap may be generated between the polymer and the foreign material due to the difference in thermal expansion coefficient between the polymer and the foreign material, or a curve may be formed on the surface of the foreign material due to the difference in thermal expansion coefficient between two or more foreign materials. Adhesion between the foreign material and the polymer may be reduced by bending the surface of the foreign material.

And, in the laser irradiation step (S2), the position of the laser device, the laser irradiation angle, and the on/off of the laser can be controlled so that the laser can be irradiated only on the waste plastic area containing the foreign matter detected by the foreign matter detection step (S1). can

Foreign matter separation step (S3)

In the foreign matter separation step (S3), the thermally expanded or thermally contracted foreign matter may be separated from the polymer contained in the waste plastic by fixing it with a jig. In the foreign matter separation step (S3), the position of the jig may be adjusted to an area containing the foreign matter detected in the foreign matter detection step (S1).

In the foreign matter separation step (S3), the foreign matter may be physically removed by moving the jig after fixing the foreign matter with a jig.

Although the above has been described with reference to preferred embodiments of the present invention, those skilled in the art will variously modify and change the present invention within the scope not departing from the spirit and scope of the present invention described in the claims below. You will understand that it can be done.

100: waste plastic treatment system
10: sensing device
20: laser device
30: jig
40: control unit

Claims (11)

A detection device for detecting foreign substances contained in waste plastic;
a laser device for thermally expanding or contracting at least one of a polymer and foreign matter contained in the waste plastic by irradiating a laser onto an area containing the foreign matter detected by the sensing device; and
A jig that fixes and removes the foreign matter that is thermally expanded or contracted by the laser and has a gap between the polymer and the polymer.
Waste plastic treatment system comprising a.
The waste plastic treatment system according to claim 1, wherein the laser device includes an infrared laser or a carbon dioxide gas laser.
The waste plastic processing system according to claim 1, wherein the laser device emits a laser having a wavelength of 350 nm to 10400 nm.
The waste plastic treatment system of claim 1, wherein the foreign material includes at least one of urethane and polystyrene.
The waste plastic processing system according to claim 1, further comprising a control unit controlling the laser device so that the laser is radiated only to an area containing the foreign matter detected by the detection device.
The waste plastic treatment system according to claim 1, further comprising a pre-processing unit that performs at least one of crushing, crushing, and sorting of the waste plastic.
In the waste plastic treatment method comprising a crushing step, a crushing step, and a sorting step,
A laser irradiation step of thermally expanding or contracting the foreign material by irradiating a laser to a region containing the foreign material in the waste plastic; and
Foreign matter separation step of fixing the thermally expanded or thermally contracted foreign matter with a jig to separate it from the polymer contained in the waste plastic
Waste plastic treatment method comprising a.
The waste plastic processing method of claim 7, further comprising a foreign matter detection step of scanning the waste plastic and detecting an area containing the foreign matter.
The method of claim 7, wherein the laser irradiation step and the foreign matter separation step are performed before the crushing step.
The method of claim 7, wherein the laser irradiation step and the foreign matter separation step are performed after the crushing step and before the crushing step.
The method of claim 7, wherein the laser irradiation step and the foreign matter separation step are performed after the crushing step and before the sorting step.

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