JP5367145B1 - Black waste plastic material sorting device - Google Patents

Abstract

A black waste plastic material sorting device capable of quickly sorting a large amount of black waste plastic pieces with high accuracy is provided.
In a black waste plastic material sorting device that sorts black waste plastic by material, infrared rays are irradiated to the black waste plastic piece, and the mid-infrared reflection spectrum from the black waste plastic piece is registered in advance for each material. The material of the black waste plastic is selected by comparing and collating with the spectrum in the wavelength region of 3 μm or more.
[Selection] Figure 5

Description

  TECHNICAL FIELD The present invention relates to a black waste plastic material sorting device that can automatically sort a material of a crushed black waste plastic piece derived from a waste home appliance or the like in large quantities with high accuracy.

  Development of recycling technology for waste plastics has become one of the important issues for the recent increase of waste and effective utilization of limited resources. Waste plastic recycling methods can be broadly divided into material recycling, which recycles materials and products, and thermal recycling, which recovers and uses thermal energy generated during incineration. In particular, since material recycling can reduce the production amount of plastics, it can reduce the amount of carbon dioxide that causes global warming, and is currently attracting the most attention.

  In order to recycle materials, if waste plastics of different materials are mixed into the collected waste plastics, the characteristics of the recycled plastics are degraded. Therefore, a technique for sorting the collected waste plastics with high accuracy is required.

  In particular, there is a recent demand for a technique for highly accurately selecting black waste plastic materials generated in large quantities from large waste such as waste home appliances and automobiles in which black resin such as polypropylene is used. Techniques disclosed in Patent Documents 1 to 4 are known as techniques for selecting such black waste plastic materials.

  The technique disclosed in Patent Document 1 obtains a diffraction pattern of radiation diffracted by a resin material when the resin material is irradiated with radiation, and this diffraction pattern is prepared in advance as a component to be analyzed, for example, a flame retardant. Whether or not the component is contained in the resin material is determined by comparison with the diffraction pattern of the flame retardant aid. According to this technique, even if the surface of the resin material is coated, the resin material can be selected without peeling off the coating.

  Further, the technique disclosed in Patent Document 2 measures a Raman scattering spectrum of Raman scattered light scattered from a plastic to be identified when the plastic to be identified is irradiated with laser light, and a known peak position of the Raman scattering spectrum and By comparing the Raman scattering intensity at the Raman shift wave number corresponding to the known baseline position with the Raman scattering intensity at the known peak position and the known baseline position prepared for each plastic material in advance, the plastic material is identified at high speed. be able to.

  The technique disclosed in Patent Document 3 is obtained by measuring transmitted light or reflected light when a plastic sample is irradiated with infrared light, and analyzing a spectrum in the mid-infrared region (wavelength range: 2.5 to 25 μm). Based on the obtained information, it is possible to determine the type of plastic constituting the plastic sample, and the grade relating to rigidity, impact absorption, and the like.

  Furthermore, the technique disclosed in Patent Document 4 is a technique for thinning a first plastic piece and a second plastic piece made of different crushed materials into an extruding roller that applies a certain pressure and a heated rolling roller. The material is identified by comparing the infrared transmission spectrum detected by the infrared detector with the infrared transmission spectrum of a known plastic using an identification device. According to the technique disclosed in Patent Document 4, plastic flakes can be sorted by material.

JP 2005-003440 A Patent No. 4203916 JP 2001-074650 A JP 2010-110733 A

  However, the sorting method disclosed in Patent Document 1 is not practical because the device itself is expensive because it uses radiation. In addition, since the reflection angle differs depending on the shape of the object, it is necessary to adjust the angle of the object, and it has not been possible to sort quickly.

  Moreover, the identification method disclosed in Patent Document 2 has a problem that when a black plastic containing a carbon filler is irradiated with strong laser light, the plastic melts due to heat generated by the absorption of the carbon filler, and the Raman scattering spectrum cannot be measured. was there. When weak laser light is irradiated to prevent melting of the plastic, the signal intensity is insufficient, and it is necessary to irradiate the signal for a long time to integrate the signals. There was a problem that a large measurement could not be performed.

  In addition, the identification method disclosed in Patent Document 3 needs to select a measurement method in consideration of the shape, surface properties, color, and transmittance of the plastic sample, and pre-treat the plastic sample as necessary. . When the plastic sample is made of a black resin, since infrared rays are almost absorbed, the regular reflection method cannot be used, and measurement by the total reflection method (ATR method) is necessary. However, the total reflection method (ATR method) requires the installation of an ATR crystal at the lower part of the object, so that it is difficult to adopt it for an identification device using a belt conveyor that is used at a normal work site. Met.

  Furthermore, since the sorting method disclosed in Patent Document 4 is based on the transmission method, a cumbersome pretreatment of thinning the object in advance is necessary.

  Accordingly, the problem to be solved by the present invention is to provide a black waste plastic material sorting device capable of quickly sorting a large amount of black waste plastic pieces with high accuracy.

  In order to solve the above problems, the present inventor has intensively studied from various viewpoints. As a result, the following inference was obtained.

  In order to identify a plastic material with high accuracy, it is necessary to obtain more information for identifying the material. The spectrum in the mid-infrared region contains more identifying information than the spectrum in the near-infrared region. However, when the plastic is black, the carbon filler contained in the black plastic absorbs infrared rays, so it is difficult to detect the spectrum in the mid-infrared region.

  Therefore, if the infrared absorption rate of the carbon filler is investigated and a spectrum in the mid-infrared region with a low infrared absorption rate can be found, the mid-infrared spectrum from black waste plastic by specular reflection can be detected in that region. It is possible to identify the material of the black waste plastic with high accuracy by comparing and comparing the detected spectrum with the spectrum of the mid-infrared region previously examined for each material.

  Therefore, the present inventor obtained an inference that the mid-infrared absorptivity by the carbon filler is small when the wavelength region is 3 μm or more, based on the consideration of the infrared absorptance of carbon described later. Furthermore, based on the inference, the present inventors have found that the above-mentioned problem can be solved by an apparatus for identifying black plastic waste by analyzing the spectrum in the mid-infrared region measured by the specular reflection method.

That is, the black waste plastic material sorting device according to claim 1 is configured to supply supply means for sequentially supplying black waste plastic pieces crushed to about 5 to 10 mm, and the black waste plastic pieces supplied by the supply means. Infrared direct reflection from all black waste plastic pieces in the conveyance conveyor width direction of the conveyance means, conveying means for sequentially conveying, irradiation means for simultaneously irradiating infrared rays to the plurality of black waste plastic pieces in the conveyor width direction the line spectral method infrared region in the above 3μm light, and the spectrum detecting means for performing spectrum detection of the conveyor width direction all black waste plastic pieces simultaneously, have been of the conveyor width direction all detected by the spectrum detecting means the spectrum of black waste plastic pieces, spectrum registered in advance for each material Are compared with each other in a wavelength region of 3 μm or more, and material identification means for simultaneously identifying a plurality of materials of the black waste plastic piece, and air is injected from the side or obliquely in a direction intersecting the conveyance direction by the conveyance means. A plurality of spray nozzles are provided, and according to the result of the material identification means, a selection means for spraying air from the plurality of spray nozzles and simultaneously dropping a plurality of black waste plastic pieces corresponding to the result of the material identification means; And collecting means for collecting, for each material, a plurality of black waste plastic pieces falling by the sorting means.

  According to the black waste plastic material selection device of the first aspect, since the wavelength region has a small infrared absorption rate by the carbon filler, a spectrum having a sufficient intensity can be obtained. That is, it becomes possible to measure the spectrum of black waste plastic, which has been difficult with the conventional apparatus, by the specular reflection method, and it is possible to manufacture the apparatus at a lower cost than when other electromagnetic wave measurements are employed.

  Further, according to the black plastic waste material sorting apparatus according to claim 1, since the spectrum in the mid-infrared region is analyzed, the information for identifying the material increases, and the material can be identified with higher accuracy. it can.

  Further, according to the black plastic waste material sorting apparatus according to claim 1, since the spectrum can be measured by the specular reflection method, the ATR crystal, which is essential for the total reflection method, is placed below the black waste plastic piece. Therefore, it can be employed in a normal work site using a belt conveyor, and a large amount of black waste plastic can be selected.

  Moreover, according to the black waste plastic material sorting apparatus according to claim 1, since it is possible to measure the spectrum by the regular reflection method, without requiring a troublesome pretreatment such as thinning the plastic in advance, The material can be identified simply by crushing the black waste plastic, improving work efficiency.

The waste plastic material sorting device according to claim 2 is a waste plastic material sorting device that sorts waste plastic by material, and sequentially supplies waste plastic pieces crushed to about 5 to 10 mm including black waste plastic pieces. Supply means, conveying means for sequentially conveying the waste plastic pieces supplied by the supply means, irradiation means for simultaneously irradiating infrared rays to the plurality of waste plastic pieces in the conveyor width direction, and the conveying means Spectral detection means for simultaneously detecting the spectrum of all black waste plastic pieces in the transport conveyor width direction by means of line spectroscopy in the mid-infrared region of 3 μm or more of the infrared reflected light directly from all black waste plastic pieces in the transport conveyor width direction ; , has been the conveyor width direction all detected by the spectrum detecting means The spectrum of Irohai plastic pieces, and advance a spectrum that is registered for each material compared collated in a wavelength range 3μm or more, a material identifying means for performing identification of the material of the waste plastic pieces plurality simultaneously, by the conveying means A plurality of injection nozzles for injecting air from the side or obliquely in the direction intersecting the transport direction are provided, and according to the result of the material identification means, the air is injected from the plurality of injection nozzles and the result of the material identification means And a collecting unit that collects a plurality of waste plastic pieces dropped by the sorting unit for each material.

  According to the waste plastic material selection apparatus according to claim 2, since the infrared absorption rate by the carbon filler is in a wavelength region, a spectrum having a sufficient intensity can be obtained even when black waste plastic is mixed. it can. In other words, the spectrum of black plastic waste, which was difficult with conventional equipment, can be measured by the specular reflection method in the same way as waste plastic pieces of other colors, making it cheaper than when using other electromagnetic wave measurements. The device can be manufactured.

  In addition, according to the waste plastic material sorting apparatus according to claim 2, since the spectrum in the mid-infrared region is analyzed, the information for identifying the material increases, and the material can be identified with higher accuracy. .

  Further, according to the waste plastic material sorting apparatus according to claim 2, since the spectrum can be measured by the regular reflection method even if the black waste plastic piece is mixed, the ATR which is essential in the total reflection method. There is no need to place the crystal under the waste plastic piece, and it can be adopted in a normal work site using a belt conveyor, and a large amount of waste plastic can be selected.

Furthermore, according to the waste plastic material sorting apparatus according to claim 2, the material can be identified with high accuracy even when waste plastic pieces of various colors other than black are mixed. There is no need to separate waste plastic pieces by color at each stage, and the material can be identified simply by crushing the waste plastic, thereby improving work efficiency.

  According to the present invention, it is possible to provide an inexpensive black plastic waste material sorting apparatus that can quickly sort a large amount of black plastic waste with high accuracy.

It is a calculation result about the infrared rays transmittance of carbon. Two kinds of black waste plastic pieces made of different materials used in the demonstration experiment. It is a reflected infrared spectrum from the black waste plastic piece of Type1. It is a reflected infrared spectrum from the black waste plastic piece of Type2. 1 is a schematic configuration diagram of a black plastic waste material sorting apparatus according to an embodiment of the present invention. It is a figure which shows the infrared absorption spectrum of the main plastics in a mid infrared region.

  Hereinafter, specific embodiments to which the present invention is applied will be described in detail with reference to experimental results and drawings.

1. Regarding the infrared absorptivity of the carbon filler First, the infrared absorptivity due to the carbon filler, which becomes a cause of inhibition when measuring the spectrum, was considered.

  The relationship between the absorption coefficient α and the extinction coefficient κ is given by α = 2ωκ / c = 4πνκ / c = 4πκ / λ, and the relationship between the transmittance Τ and the absorption coefficient α is Τ = It is given by exp (−αd). FIG. 1 is a result of calculation using the above equation by Katsuaki Sato of the Japan Science and Technology Agency, assuming that the infrared transmittance Τ of carbon is a film thickness d = 200 nm.

  According to FIG. 1, it can be seen that the longer the wavelength, the greater the transmittance and the smaller the absorptance. In particular, when the wavelength is 3 μm or more, the absorptance is extremely reduced as compared with the case where the wavelength is less than 3 μm. Further, it is considered that the amount of light falls extremely in the far infrared region. Moreover, if the absorption rate is small, it can be estimated that an inhibiting factor when measuring a spectrum that the carbon filler absorbs infrared rays can be reduced. Therefore, the following verification experiment was performed in the mid-infrared region of the wavelength range of 3 μm to 5 μm based on the above-described inference.

2. Demonstration Experiment FIG. 2 shows black waste plastic pieces of two types of materials used in the demonstration experiment. Type 1 is a black plastic piece derived from waste home appliances, and Type 2 is a black plastic piece derived from waste automobiles.

  FIG. 3 and FIG. 4 show the results of spectrum analysis of Type 1 and Type 2 with the following requirements, respectively. FIGS. 3 and 4 are obtained by irradiating black waste plastic pieces of Type 1 and Type 2 with infrared rays and measuring the reflected light using an intermediate infrared camera with a spectroscope of 3 μm to 5 μm at an exposure time of 1.7 ms. The reflected infrared spectrum.

  From the results of FIG. 3 and FIG. 4, it can be said that the positions (wavelengths) of the absorption peaks of the materials of Type 1 and Type 2 clearly appear, and the spectrum can be measured regardless of the black plastic piece. That is, in the mid-infrared region of the wavelength range of 3 μm to 5 μm, it can be said that the black plastic piece can be identified by detecting the spectrum by the reflection method because the influence of infrared absorption by the carbon filler is small.

3. Configuration of Black Waste Plastic Material Sorting Device 1 Next, an outline of the configuration of the black waste plastic material sorting device 1 will be described with reference to FIG.

  The black waste plastic material sorting apparatus 1 is supplied by supply means 11 (for example, a charging hopper 12, a transfer conveyor 13, and a charging feeder 14 in FIG. 5) and a supply means 11 for sequentially supplying black waste plastic pieces P. Conveying means 21 (for example, a conveyer 22 in FIG. 5) for conveying the black waste plastic piece P is provided as a main part.

  The sorting apparatus 1 includes an irradiation unit 31 (for example, an infrared light source 32 in FIG. 5) that irradiates the black waste plastic piece P with infrared rays, and a reflection spectrum detection unit 41 that detects a reflection spectrum from the black waste plastic piece P. (For example, the mid-infrared sensor 42 in FIG. 5) and the material identification means for identifying the material of the black waste plastic piece P by comparing the reflection spectrum detected by the detection means 41 with a spectrum registered in advance for each material. 51 (for example, the discriminating device 52 in FIG. 5) as a main part.

  Further, the sorting apparatus 1 is provided with an injection nozzle 62 that injects air from the side or obliquely in a direction crossing the conveyance direction by the conveyance means 21, and the injection nozzle 62 determines whether the material identification means 51 determines the result. Sorting means 61 (for example, the discriminating device 52, the injection nozzle 62 in FIG. 5) that drops the black waste plastic piece P of the material corresponding to the result of the material identification means 51 by jetting air, and the black that is dropped by the sorting means 61. A recovery means 71 (for example, a recovery hopper 72 in FIG. 5) for recovering the waste plastic piece P for each material is provided as a main part.

  The supply unit 11 includes, for example, a charging hopper 12, a transfer conveyor 13, and a charging feeder 14. The charging hopper 12 is configured to receive the crushed black waste plastic piece P. The transfer conveyor 13 supplies the black waste plastic piece P supplied from the input hopper 12 to the input feeder 14. The input feeder 14 is composed of a vibration feeder, an electromagnetic feeder, or the like, and supplies it to the conveying means 21 while preventing the black waste plastic pieces P from overlapping each other by vibrating.

  The transport means 21 is composed of, for example, a transport conveyor 22. The conveyor 22 conveys the black waste plastic piece P in a direction away from the supply means 11.

  The irradiation means 31 is composed of an infrared light source 32 such as a halogen tungsten lamp. The infrared light source 32 has a function of irradiating infrared rays toward the black waste plastic piece P. Moreover, the infrared light source 32 is installed so that the reflected light from the black waste plastic piece P may enter the mid-infrared sensor 42, and is installed on the upper side or the upper side of the transport conveyor 22 in the flow direction.

  The reflection spectrum detection means 41 includes a mid-infrared sensor 42. The mid-infrared sensor 42 is constituted by a spectroscope-equipped camera having a mid-infrared wavelength region of 3 μm or more, for example. The mid-infrared sensor 42 receives near-infrared reflected light from the black waste plastic piece P, and outputs the light reception result to a determination device 52 such as a computer.

  As the camera with a spectroscope for the mid-infrared sensor 42, a camera having a resolution of 320 dots may be used so that the infrared spectrum can be measured at a time in 320 points in the width direction of the conveyor 22 at a time. At this time, if the size of the black waste plastic piece P is about 5 mm square, all the black waste plastic pieces P in the width direction of the transport conveyor 22 can be measured at a time by measuring at intervals of 4 mm. The width of the conveyor 22 is, for example, 1400 mm because the effective width of measurement is 4 mm × 320 = 1280 mm.

  Also, the flow speed of the conveyor 22 can be measured at 1.7 ms because the exposure time of the spectroscopic camera can be measured at a maximum of 590 times per second, and the spectroscopic camera is 400 frames / second. Since the speed is 4 mm × 400 times / second × 60 seconds / minute = 96 m / minute, all black waste plastic pieces P flowing on the conveyor 22 can be measured.

  Moreover, when the size of the black waste plastic piece P is about 6 to 10 mm square, all black waste plastic pieces P in the width direction of the conveyor 22 can be measured by measuring at intervals of 6 mm. Since the effective width of the measurement is 6 mm × 320 = 1920 mm, the width of the conveyor 22 is, for example, 2000 mm.

  Moreover, since the flow speed of the conveyor 22 is 6 mm × 400 times / second × 60 seconds / minute = 144 m / minute, all the black waste plastic pieces P flowing on the conveyor 22 can be measured.

  According to the relationship between the width and speed of the conveyor 22 described above, the black plastic waste piece P can be processed at about 1 ton or more per hour.

  The material identification means 51 is comprised by discrimination | determination apparatuses 52, such as a computer, for example. The discriminator 52 compares the received light reception result with a spectrum registered in advance for each material in a wavelength region of 3 μm or more. Then, if the spectra match as a result of the comparison and collation, the discriminating device 52 discriminates (identifies) the material as having the spectrum, and based on the discrimination result, sends a signal for controlling the air injection of the sorting means 61. Send.

  Specifically, the determination device 52 obtains an absorption peak from the reflected light, and the position (wavelength) of the absorption peak is, for example, the position of the absorption peak of the infrared absorption spectrum of the main plastic in the mid-infrared region shown in FIG. Is determined (identified) as a material having the characteristic. The material may be specified not only from the absorption peak but also by pattern matching between the spectrum of the reflected light and the known spectrum for each material.

  The sorting unit 61 includes a determination device 52 and an air injection nozzle 62. For example, a plurality of injection nozzles 62 are arranged in order for each material from upstream to downstream of the conveyor 22. The air injection nozzle 62 that has received the control signal from the determination device 52 opens a nozzle port (not shown) and injects air.

  For the black waste plastic piece P on the conveyor 22, the discriminating device 52 selects the air injection nozzle 62 according to the material from among the plurality of air injection nozzles 62, and transmits a control signal at a timing. As a result, air is received from the air injection nozzle 62 that has received the control signal, and is blown off to the recovery hopper 72 provided for each material. Since it can blow off for every material of the black waste plastic piece P, the material of the black waste plastic piece P recovered as it is without being blown off can also be identified.

  The collection means 71 is constituted by a collection hopper 72. The collection hopper 72 is provided for each type of material selected at the lower part of the conveyor 22 and is configured to collect the falling black waste plastic piece P.

4). Operation of Black Waste Plastic Material Sorting Device 1 Finally, the operation of the sorting device 1 will be described. In addition, description is abbreviate | omitted about the part which overlaps with description of the item of "3. Structure of the black waste plastic material selection apparatus 1".

  The conveyer 22 conveys the black waste plastic piece P supplied from the supply means 11 to the downstream without causing any overlap while giving vibration.

  The mid-infrared sensor 42 receives the reflected light of the infrared black waste plastic piece P emitted from the infrared light source 32 and outputs the light reception result to a determination device 52 such as a computer.

  The determination device 52 identifies the material of the black waste plastic piece P from the position (wavelength) of the absorption peak of the light reception result input from the mid-infrared sensor 42.

  The discriminating device 52 selects the air injection nozzle 62 corresponding to the material among the plurality of air injection nozzles 62 arranged, and transmits a control signal at a timing.

  The air injection nozzle 62 that has received the control signal opens the nozzle port and injects air.

  The black plastic waste P on the transport conveyor 22 receives air from the air injection nozzle 62 that has received the control signal, and is blown off by the recovery hopper 72 provided for each material and dropped and recovered. Since it can blow off for every material of the black waste plastic piece P, the material of the black waste plastic piece P recovered by dropping into the recovery hopper 72 without being blown off can be identified.

  It should be noted that the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the scope of the present invention.

DESCRIPTION OF SYMBOLS 1 Black waste plastic material identification apparatus 11 Supply means 12 Input hopper 13 Transfer conveyor 14 Input feeder 21 Transfer means 22 Transfer conveyor 31 Irradiation means 32 Infrared light source 41 Reflection spectrum detection means 42 Middle infrared sensor 51 Material identification means 52 Discriminator 61 Sorting device Means 62 Air injection nozzle P Black waste plastic piece

Claims (2)

Supply means for sequentially supplying black waste plastic pieces crushed to about 5 to 10 mm ;
Conveying means for sequentially conveying the black waste plastic pieces supplied by the supplying means;
Irradiation means for simultaneously irradiating the plurality of black waste plastic pieces with infrared rays in the conveyor width direction ;
The spectral detection of all black waste plastic pieces in the width direction of the conveyer is performed simultaneously by the line spectroscopy in the mid-infrared region of 3 μm or more of the infrared direct reflected light from all black waste plastic pieces in the width direction of the conveyer of the transfer means. Spectrum detecting means;
The spectrum of all the black waste plastic pieces detected in the width direction of the conveyer detected by the spectrum detection means is compared with the spectrum registered in advance for each material in a wavelength region of 3 μm or more, and the black waste plastic pieces Material identification means for simultaneously identifying a plurality of materials,
A plurality of injection nozzles for injecting air from the side or obliquely in a direction intersecting the conveying direction by the conveying means are provided, and material is obtained by injecting air from the plurality of the injection nozzles according to the result of the material identifying means. Sorting means for simultaneously dropping a plurality of black plastic waste pieces corresponding to the result of the identification means;
A black waste plastic material sorting device comprising: a collecting means for collecting a plurality of black waste plastic pieces falling by the sorting means for each material. In waste plastic material sorting equipment that sorts waste plastic by material,
Supply means for sequentially supplying waste plastic pieces crushed to about 5 to 10 mm including black waste plastic pieces;
Conveying means for sequentially conveying the waste plastic pieces supplied by the supplying means;
Irradiation means for simultaneously irradiating infrared rays to the plurality of waste plastic pieces in the conveyor width direction ;
The spectral detection of all black waste plastic pieces in the width direction of the conveyer is performed simultaneously by the line spectroscopy in the mid-infrared region of 3 μm or more of the infrared direct reflected light from all black waste plastic pieces in the width direction of the conveyer of the transfer means. Spectrum detecting means;
By comparing and collating the spectrum of all black waste plastic pieces in the width direction of the conveyer detected by the spectrum detecting means with the spectrum registered in advance for each material in a wavelength region of 3 μm or more, the material of the waste plastic pieces Material identification means for simultaneously identifying a plurality of
A plurality of injection nozzles for injecting air from the side or obliquely in a direction intersecting the conveying direction by the conveying means are provided, and material is obtained by injecting air from the plurality of the injection nozzles according to the result of the material identifying means. Sorting means for simultaneously dropping a plurality of waste plastic pieces corresponding to the result of the identification means;
A waste plastic material sorting device, comprising: a collecting means for collecting a plurality of waste plastic pieces dropped by the sorting means for each material.