JP2003284970A - Device for sorted recovery of used plastic and operation method therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a device for sorted recovery of a used plastic and a operating method therefor capable of stabilizing the operation in response to the increase or decrease in slurry volume in a slurry mixing tank and dealing with slurry or water running over a rotor when the rotor is stopped. <P>SOLUTION: The slurry mixing tank is provided with an upper limit level detection means to detect the slurry rising to the upper limit level, a lower limit level detection means to detect the slurry declining to the lower limit level, and an outlet to discharge the slurry. Moreover, a lightweight plastic piece discharge gate valve and a medium-weight plastic piece discharge gate valve are installed to a lightweight plastic piece discharge chute and a medium- weight plastic piece discharge chute from the rotor, respectively, for their opening and closing. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a used plastic separating and collecting apparatus and a method for operating the same, and particularly to a used plastic suitable for use when the amount of slurry in a slurry mixing tank is increased or decreased and rotation of a rotor is stopped. The present invention relates to a plastic separation and recovery device and an operating method thereof.

[0002]

2. Description of the Related Art FIG. 3 is an apparatus configuration diagram for explaining a method for separating chlorine-containing plastic from used plastic in a conventional centrifugal type gravity separation apparatus disclosed in Japanese Patent Laid-Open No. 2000-254542. In FIG. 3, the waste plastic 1 crushed to about 20 mm or less in advance is put into the slurry mixing tank (same as the washing and mixing tank) 20 by the waste plastic feeding conveyor 10 and stirred by the stirrer 30 to obtain the specific gravity liquid or water 2
It is washed and mixed with (hereinafter, referred to as water 2) to form a slurry 3.

Then, the slurry 3 of the waste plastic 1 and the water 2 is supplied to the main body 50 (separation tank) of the centrifugal specific gravity separator by the slurry supply pump 40, where it is reused according to the difference in specific gravity with respect to the water 2. It is separated into a light weight plastic 4 useful for the above and a medium weight plastic 5 containing a chlorine-containing plastic.

That is, the slurry 3 jetted into the rotor 52 from substantially the axial center of the screw shaft 51 receives a centrifugal force in the rotating rotor 52 to form a cylindrical water surface 53. Then, the light weight plastic 4 lighter than the water 2 floats above the water surface 53, while the medium weight plastic 5 heavier than the water 2 sinks toward the inner wall.

The floated lightweight plastic 4 is carried to one side by a lightweight screw conveyor 54 and discharged from a lightweight plastic discharge chute 55, and a lightweight blower 56 is used to carry out a lightweight plastic process (for example, a granulation process or the like). ) Is transported to. On the other hand, the settled medium weight plastic 5 is the medium weight screw conveyor 57.
Is conveyed to the other by the medium weight plastic discharge chute 58 and discharged by a medium weight blower 59 to a medium weight plastic process (for example, PVC treatment process).

Further, the water 2 separated from the slurry 3 is discharged from the water discharge chute 62 and collected in the centrate tank 60. Then, the water circulating pump 70 returns to the washing and mixing tank 20 for recycling. The centrate tank 60 is provided with fresh water supply means 61 for supplying fresh water 6 (or new specific gravity liquid) to secure the amount of circulating water (or specific gravity liquid). In addition, specific gravity measuring means and specific gravity adjusting means may be installed.

At this time, in supplying the slurry 3 to the main body 50 of the centrifugal specific gravity separator, a slurry flow meter 80
(Slurry supply pump 40 and centrifugal type specific gravity separator main body 5
0 is connected to the slurry supply pipe 90) and the flow rate of the slurry 3 supplied is measured, and the speed of the waste plastic feeding conveyor 10 is controlled according to the measured value so as to maintain a constant plastic concentration and a constant plastic concentration. The amount of the waste plastic 1 charged into the washing and mixing tank 20 is controlled so that the slurry flow rate becomes.

Thus, the amount of waste plastic supplied to the centrifugal specific gravity separator 50 is adjusted to a predetermined value. Specifically, when the flow rate of the slurry 3 decreases, the plastic concentration increases, so the waste plastic loading conveyor 1
Control is performed to reduce the charging rate of 0 to lower the slurry concentration in the slurry mixing tank 20. On the other hand, when the slurry flow rate increases, the waste plastic loading conveyor 10
Is controlled to increase the slurry concentration in the slurry mixing tank 20.

Therefore, the abnormal discharge of the lightweight plastic from the centrifugal specific gravity separator 50 (reduction of discharge amount or stop of discharge, hereinafter referred to as clogging) is prevented. Also,
Since the separation efficiency can be maintained at a high level, it is possible to stably obtain the lightweight plastic 4 in which the mixing of the chlorine-containing plastic is suppressed to 1% or less. Then, the lightweight plastic 4 can be granulated and used for various reuses as a blast furnace raw material, RDF, and the like, thus providing a useful effect.

In order to prevent the waste plastic 1 charged from the waste plastic loading conveyor 10 from accumulating in the stutter 11 and to smoothly discharge the lightweight plastic 4 from the lightweight plastic discharge chute 55,
In order to facilitate the discharge of the medium-weight plastic 5 from the medium-weight plastic discharge chute 58, a predetermined amount of water 2 is sprayed on the relevant portion, and spray water pipes 110, 120 for supplying the water 2 for this purpose. 130 are arranged.

[0011]

However, in the above-mentioned conventional technique, variations in the properties of the used plastic 1 (the same as waste plastic) or the slurry 3 are used.
There is a case where the amount of slurry in the slurry mixing tank 20 increases or decreases (same as raising and lowering the liquid level) due to variations in the concentration of. At this time, there is a problem that clogging may occur in the rotor 52 only by returning the amount of slurry to an appropriate range. Further, when the rotor 52 is stopped, the slurry 3 or the water 2 attached to the inner wall surface of the rotor 52 moves (falls) downward due to the centrifugal force, which causes a problem of overflowing from the rotor 52.

The present invention has been made to solve the above problems, and stabilizes the subsequent operation in response to the increase and decrease of the amount of slurry in the slurry mixing tank, and when the rotor is stopped. Another object of the present invention is to obtain a used plastic fractional recovery device for treating slurry or water overflowing from a rotor and its operating method.

[0013]

The used plastic sorting and collecting apparatus according to the present invention is as follows. (1) A slurry mixing tank that mixes the used plastic into a slurry by mixing with a specific gravity liquid or water, and a lightweight plastic mixed with the used plastic by applying a centrifugal force to the supplied slurry. A used plastic separation and recovery device having a rotor for separating heavy-weight plastics and a screw shaft for discharging the separated light-weight plastics and medium-weight plastics to a light-weight plastic discharge chute and a medium-weight plastic discharge chute, respectively. There, the slurry mixing tank, an upper limit level detecting means for detecting that the slurry has risen to an upper limit level, and a lower limit level detecting means for detecting that the slurry has dropped to a lower limit level, and Equipped with a discharge port for discharging the slurry And it is characterized in Rukoto.

(2) A slurry mixing tank in which the used plastic that has been input is mixed with a specific gravity liquid or water to form a slurry, and a lightweight material that is mixed with the used plastic by applying a centrifugal force to the supplied slurry. Disposal of used plastic having a rotor for separating plastic from medium-weight plastic and a screw shaft for discharging the separated lightweight plastic and medium-weight plastic to a lightweight plastic discharge chute and a medium-weight plastic discharge chute, respectively The recovery device is characterized in that a light weight plastic discharge gate valve and a medium weight plastic discharge gate valve for opening and closing the light weight plastic discharge chute and the medium weight plastic discharge chute, respectively, are installed.

Further, the method of using the used plastic separating and collecting apparatus according to the present invention is as follows. (3) A lightweight plastic mixed with the used plastic by supplying a slurry obtained by mixing the used plastic with a specific gravity liquid or water in a slurry mixing tank into a rotating rotor to give a centrifugal force. In a used plastic sorting and collecting device that separates the medium-weight plastics and discharges the separated lightweight plastics and the medium-weight plastics to the lightweight plastic discharge chute and the medium-weight plastic discharge chute by a screw shaft that rotates, respectively, When the amount of slurry in the slurry mixing tank decreases below a predetermined amount, the amount of used plastic supplied to the slurry mixing tank is reduced and the amount of specific gravity liquid or water supplied to the slurry mixing tank is increased. It is an feature.

(4) In (3), the amount of used plastic supplied to the slurry mixing tank is reduced to about 0.5 times, and the amount of specific gravity liquid or water supplied to the slurry mixing tank is reduced to about 0.5. It is characterized by an increase of 1.5 times.

(5) Light weight mixed with the used plastic by supplying a slurry prepared by mixing the used plastic with a specific gravity liquid or water in a slurry mixing tank into a rotating rotor to impart a centrifugal force. Waste plastic and medium weight plastic are separated, and the separated light weight plastic and medium weight plastic are discharged to a light weight plastic discharge chute and a medium weight plastic discharge chute by a rotating screw shaft, respectively. In the apparatus, when the slurry in the slurry mixing tank increases above a predetermined amount, the supply of the used plastic and the specific gravity liquid or water to the slurry mixing tank is stopped, and the slurry is mixed with the slurry mixing tank. Al is characterized in that the discharge.

(6) Light weight mixed with the used plastic by supplying a slurry prepared by mixing the used plastic and the specific gravity liquid or water in a slurry mixing tank into a rotating rotor to impart a centrifugal force. Waste plastic and medium weight plastic are separated, and the separated light weight plastic and medium weight plastic are discharged to a light weight plastic discharge chute and a medium weight plastic discharge chute by a rotating screw shaft, respectively. In the apparatus, the rotor continues to rotate while decelerating for a predetermined time after stopping the supply of the slurry into the rotor, and when the rotor decelerates to a predetermined rotation speed, the lightweight plastic Discharge chute and medium weight plus It is characterized in that closing the click discharge chute.

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION [Embodiment 1] FIG. 1 is an apparatus configuration diagram showing the configuration of a used plastic sorting and collecting apparatus according to Embodiment 1 of the present invention. The same parts as those of the conventional technique (FIG. 3) are denoted by the same reference numerals, and part of the description will be omitted. In FIG. 1, 210 is an upper limit level detection sensor for detecting that the slurry 3 installed in the slurry mixing tank 20 has risen to the upper limit level, 22
0 is a lower limit level detection sensor that detects that the slurry 3 has dropped to the lower limit level (no slurry is present), 2
00 is a control unit that receives the detection results of the upper limit level detection sensor 210 and the lower limit level detection sensor 220 and issues a predetermined control signal, and 300 is the slurry mixing tank 20.
A slurry discharge pipe for discharging the slurry 3 from
Reference numeral 0 is a slurry discharge opening / closing valve installed in the slurry discharge pipe.

When the liquid level of the slurry 3 in the slurry mixing tank 20 rises for some reason and the upper limit level detection sensor 210 detects the liquid level, the detection result is input to the control unit 200. The control unit 200 issues a control signal for stopping the waste plastic loading conveyor 10 and the water circulation pump 70 and a control signal for opening the slurry discharge opening / closing valve 310 based on the input detection result. Therefore, the liquid level of the slurry drops rapidly.
During this time, the stirrer 30 continues stirring.

A plurality of upper limit level detection sensors may be arranged at different positions in the vertical direction. At this time, a control signal for stopping the waste plastic loading conveyor 10 and the water circulation pump 70 is issued based on the detection result of the lower upper limit level detection sensor, and the slurry discharge opening / closing valve 310 is based on the detection result of the upper upper limit level detection sensor. It is also possible to carry out a two-step control such as issuing a control signal for opening. Also,
The control signal for stopping the action may be issued immediately in response to the signal that the upper limit level detection sensor 210 no longer detects the liquid surface, or may be issued after a predetermined time delay from the signal.

On the other hand, when the liquid level of the slurry 3 in the slurry mixing tank 20 is lowered for some reason and the lower limit level detection sensor 220 detects the liquid level (detects that there is no slurry), the detection result is the control unit. 200 is input. Based on this, the control unit 200 issues a control signal for slowing the transport speed of the waste plastic loading conveyor 10 and increasing the discharge amount of the water circulation pump 70. For example, the input amount of waste plastic 1 is reduced to about half, and the supply amount of water 2 is set to about 1.
5 times increase.

Therefore, the liquid level of the slurry 3 rises. At this time, the slurry mixing tank 20
The slurry 3 therein is diluted, and its concentration (ratio of waste plastic 1 to water 2) decreases. For example, when the liquid level drops, the slurry 3 in the slurry mixing tank 20
Even if the density of (1) becomes high (dark), such control will reduce it to an appropriate level. Therefore, the load on the slurry supply pump 40 and the centrifugal specific gravity separator main body 50 can be suppressed while the liquid level of the slurry 3 returns to the normal level.

A plurality of lower limit level detection sensors may be arranged at different positions in the vertical direction. At this time, for example, based on the detection result of the upper lower limit level detection sensor, a control signal for increasing the supply amount of the water 2 by about 1.5 times is issued, and based on the detection result of the lower lower limit level detection sensor. In addition, a two-step control may be performed such that a control signal for reducing the input amount of the waste plastic 1 to about half is issued. Further, the control signal for stopping the action may be issued immediately in response to the signal that the lower limit level detection sensor 210 has detected the liquid surface, or may be issued after a predetermined time delay from the signal.

[Second Embodiment] FIG. 2 is an apparatus configuration diagram showing the configuration of a used plastic sorting and collecting apparatus according to a second embodiment of the present invention. The same parts as those of the conventional technique (FIG. 3) are denoted by the same reference numerals, and part of the description will be omitted. In FIG. 2, 400 is a lightweight plastic discharge gate valve installed on the lightweight plastic discharge chute 55, and 410 is a lightweight plastic discharge gate valve 4.
00, a light weight side water discharge pipe connecting the light weight plastic discharge chute 55 and the water discharge chute 62, 420
Is a lightweight object side water opening / closing valve installed in the lightweight object side water discharge pipe 410. Further, reference numeral 500 denotes a medium weight plastic discharge gate valve installed on the medium weight plastic discharge chute 58, and 510 connects the medium weight plastic discharge chute 58 and the water discharge chute 62 upstream of the medium weight plastic discharge gate valve 500. The medium weight water outlet pipe 520 is a medium weight water opening / closing valve installed in the medium weight water outlet pipe 510.

Therefore, when the rotation of the rotor 52 is stopped, the operation can be performed in the following manner. The supply of the slurry 3 to the rotor 52 is stopped. The rotational drive of the rotor 52 is stopped, and the inertial rotation state under natural deceleration or forced deceleration is set. On the other hand, the rotation of the screw shaft 51 is continued, and the separated light weight plastic 4 and medium weight plastic 5 are respectively discharged from the light weight plastic discharge chute 55.
And the medium weight plastic discharge chute 58.

When the rotation of the rotor 52 slows down and reaches a predetermined number of rotations, the rotation of the lightweight blower 56 is stopped and the lightweight plastic discharge gate valve 400 is closed. Further, the rotation of the medium weight blower 59 is stopped and the medium weight plastic discharge gate valve 500 is closed. When the rotation of the rotor 52 further slows down, the water 2 overflowing from the rotor 52 is discharged into the lightweight plastic discharge chute 55 and the medium weight plastic discharge chute 5.
8 and the water discharge chute 62.

When the light weight side water opening / closing valve 420 and the medium weight side water opening / closing valve 520 are opened, the light weight side water opening / closing valve 400 and the medium weight side water opening / closing valve 50 are opened.
The water 2 stored on the upstream side of 0 flows into the centrate tank 60 via the water discharge chute 62.

That is, since the water 2 overflowing from the rotor 52 does not reach the lightweight blower 56 and the medium weight blower 59, the water 2 may enter the inside of the lightweight blower 56 and the medium weight blower 59. Absent. Moreover, the water 2 is not conveyed to the next process. Therefore, the risk of equipment failure is reduced, and the work in the next process is not disturbed.

In addition, the present invention relates to the light side water opening / closing valve 40.
0 and the water 2 stored on the upstream side of the medium weight water opening / closing valve 500 are not limited to those that flow into the centrate tank 60, but a slurry treatment system (precipitation shown in FIG. It may be conveyed to the item side). Further, the timing of stopping the rotation of the lightweight blower 56 to close the lightweight plastic discharge gate valve 400 (the same timing as stopping the rotation of the medium weight blower 59 to close the medium weight plastic discharge gate valve 500). Is not limited to the one in which the rotation speed of the rotor 52 is used as a standard, and may be a time point when a predetermined time has elapsed after the rotational driving of the rotor 52 was stopped.

[0031]

As described above, according to the present invention, the following effects can be obtained. 1) Since the upper limit level detection sensor for measuring the liquid level of the slurry and the slurry discharge opening / closing valve for discharging the slurry are installed in the slurry mixing tank, the liquid level of the raised slurry can be rapidly lowered. 2) A lower limit level detection sensor for measuring the liquid level of the slurry is installed in the slurry mixing tank, and when the liquid level of the slurry is lowered, the liquid level is returned to the original while diluting, so that when the liquid level of the slurry is steady While returning to the level, the burden on the slurry supply pump and the centrifugal specific gravity separator main body can be suppressed.

3) Further, a lightweight plastic discharge gate valve is installed on the lightweight plastic discharge chute,
Since a medium weight plastic discharge gate valve is installed on the medium weight plastic discharge chute, water that overflows from the rotor does not reach the light weight blower and medium weight blower when the rotor stops rotating, which may cause equipment failure. This reduces the risk of disturbing the work in the next process.

[Brief description of drawings]

FIG. 1 is an apparatus configuration diagram showing a configuration of a used plastic sorting and collecting apparatus according to a first embodiment of the present invention.

FIG. 2 is an apparatus configuration diagram showing a configuration of a used plastic sorting and collecting apparatus according to Embodiment 2 of the present invention.

FIG. 3 is an apparatus configuration diagram for explaining a method of separating chlorine-containing plastic from used plastic (same as waste plastic) by a conventional centrifugal type gravity separator.

[Explanation of symbols]

1 waste plastic 2 water 3 slurry 4 Lightweight plastic 5 Medium weight plastic 6 fresh water 10 Waste plastic loading conveyor 20 Slurry mixing tank (same as wash mixing tank) 30 stirrer 40 Slurry supply pump 50 Centrifugal specific gravity separator 60 centrate tank 70 Circulation pump 200 Control unit 210 Upper limit level detection sensor 220 Lower limit level detection sensor 300 slurry discharge pipe 310 Slurry discharge opening / closing valve 400 Lightweight plastic discharge gate valve 410 Lightweight side water discharge pipe 420 Lightweight side water opening / closing valve 500 medium weight plastic discharge gate valve 510 Water discharge pipe for medium-weight items 520 Medium weight side water opening / closing valve

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Hiroshi Nakatani             1-2-1, Marunouchi, Chiyoda-ku, Tokyo             Main Steel Pipe Co., Ltd. (72) Inventor Yasuaki Koyanagi             1-2-1, Marunouchi, Chiyoda-ku, Tokyo             Main Steel Pipe Co., Ltd. F term (reference) 4D071 AA43 AA54 AA62 AB03 AB05                       AB15 BB13 CA05 DA15                 4F301 AA11 AA21 AD05 BF09 BF25                       BF31

Claims (6)

[Claims] 1. A slurry mixing tank which mixes an input used plastic with a specific gravity liquid or water to form a slurry, and a lightweight plastic mixed with the used plastic by applying a centrifugal force to the supplied slurry. Used plastics separate collection with rotor for separating light and medium weight plastics, and screw shaft for discharging separated light weight plastics and medium weight plastics to light weight plastic discharge chute and medium weight plastic discharge chute, respectively An apparatus, wherein the slurry mixing tank is an upper limit level detecting means for detecting that the slurry has risen to an upper limit level, and a lower limit level detecting means for detecting that the slurry has fallen to a lower limit level. , An outlet for discharging the slurry And a used plastic separating and collecting apparatus. 2. A slurry mixing tank in which the used plastic that is input is mixed with a specific gravity liquid or water to form a slurry, and a lightweight plastic mixed with the used plastic by applying a centrifugal force to the supplied slurry. Used plastics separate collection with rotor for separating light and medium weight plastics, and screw shaft for discharging separated light weight plastics and medium weight plastics to light weight plastic discharge chute and medium weight plastic discharge chute, respectively The device is provided with a light weight plastic discharge gate valve and a medium weight plastic discharge gate valve for opening and closing the light weight plastic discharge chute and the medium weight plastic discharge chute, respectively. A separate collection device. 3. A lightweight material mixed with the used plastic by supplying a slurry obtained by mixing the used plastic with a specific gravity liquid or water in a slurry mixing tank into a rotating rotor to impart a centrifugal force. Used plastic sorting and collecting device that separates plastics from medium-weight plastics and discharges the separated lightweight plastics and medium-weight plastics to a lightweight plastic discharge chute and a medium-weight plastic discharge chute by a rotating screw shaft, respectively. In, when the slurry in the slurry mixing tank is reduced below a predetermined amount, the amount of used plastic supplied to the slurry mixing tank is reduced, and the amount of specific gravity liquid or water supplied to the slurry mixing tank is increased. How the operation of the used plastic fractional recovery apparatus according to claim Rukoto. 4. The amount of used plastic supplied to the slurry mixing tank is reduced to about 0.5 times, and the amount of specific gravity liquid or water supplied to the slurry mixing tank is increased to about 1.5 times. 4. The method for operating a used plastic separation and recovery apparatus according to claim 3, wherein. 5. A lightweight material mixed with the used plastic by supplying a slurry obtained by mixing the used plastic with a specific gravity liquid or water in a slurry mixing tank into a rotating rotor to impart a centrifugal force. Used plastic sorting and collecting device that separates plastics from medium-weight plastics and discharges the separated lightweight plastics and medium-weight plastics to a lightweight plastic discharge chute and a medium-weight plastic discharge chute by a rotating screw shaft, respectively. In, when the slurry of the slurry mixing tank is increased above a predetermined amount, while stopping the supply of the used plastic and the specific gravity liquid or water to the slurry mixing tank, the slurry from the slurry mixing tank How the operation of the used plastic fractional recovery apparatus, characterized in that the output. 6. A lightweight product mixed in the used plastic by supplying a slurry prepared by mixing the used plastic with a specific gravity liquid or water in a slurry mixing tank into a rotating rotor to impart a centrifugal force. Used plastic sorting and collecting device that separates plastics from medium-weight plastics and discharges the separated lightweight plastics and medium-weight plastics to a lightweight plastic discharge chute and a medium-weight plastic discharge chute by a rotating screw shaft, respectively. In, for a predetermined time after stopping the supply of the slurry into the rotor, the rotor continues to rotate while decelerating,
A method for operating a used plastic sorting and collecting apparatus, wherein the lightweight plastic discharge chute and the medium weight plastic discharge chute are closed when the rotor is decelerated to a predetermined rotation speed.