KR102611943B1 - Pet chip regeneration method capable of enhancing intrinsic viscosity and purity and regeneration apparatus using the same - Google Patents

Abstract

The present invention relates to a PET chip regeneration method capable of improving the intrinsic viscosity and purity of pulverized PET chips and a PET chip regeneration device using the same. The PET chip regeneration method includes (a) preparing PET chips obtained by pulverizing PET bottles; (S10), (b) heating and rotating the PET chip in a mixer to achieve primary crystallization (S20), (c) extruding the PET chip while heating it on an extrusion screw after step S20. (S30), (d) after step S30, cutting the extruded PET raw material in water (S40), (e) after step S40, water and PET chips are separated, and then separated into pieces of a certain size by a vibration separator. Step of selecting PET chips (S50), (f) After step S50, heating and rotating the PET chips to cause secondary crystallization, and then solid phase polymerization reaction (S60), (g) After step S60, drying and cooling the PET chip (S70), and (h) packaging the recycled PET chip (S80) after step S70.

Description

PET chip regeneration method that can improve intrinsic viscosity and purity and PET chip regeneration device using the same {PET CHIP REGENERATION METHOD CAPABLE OF ENHANCING INTRINSIC VISCOSITY AND PURITY AND REGENERATION APPARATUS USING THE SAME}

The present invention relates to a chip regeneration method and regeneration device for reprocessing chips finely crushed from waste PET bottles. More specifically, the present invention relates to a chip regeneration method and regeneration device for processing chips of high purity and high quality while increasing the intrinsic viscosity of the pulverized chips. By doing so, it relates to a method and recycling device for PET bottle chips that can be reused as raw materials for long-fiber clothing materials, new PET bottles, PET sheets for vacuum forming, trays, and cups.

Polyethylene Terephthalate (hereinafter referred to as 'PET') has excellent physical and chemical properties and is used in a variety of applications such as fibers, films, tire cords, and beverage containers.

In particular, PET is manufactured in the form of a bottle and is widely used as a container for carbonated drinks, bottled water, and juice drinks.

However, these PET bottles do not rot easily, so there is a risk of polluting the environment if they are discarded as is.

Additionally, PET bottles are manufactured from expensive synthetic resins, so when they are discarded, they are a waste of resources.

Accordingly, PET bottles are collected separately and processed into chips, which are then reused as raw materials for textiles or other products.

In order to recycle the PET bottle, the label attached to the PET bottle is first separated and manufactured into chips through grinding, washing, and drying processes. The chip shape is also called a flake.

The chips manufactured in this way are classified and packaged into S class, A class, B class, etc. through a selection process. S class is used for long fibers, A class is used for sheets, and B and C classes are used for short fibers. do.

Meanwhile, methods for recycling waste PET bottles can be classified into chemical recycling, mechanical recycling, and thermal recycling.

The chemical recycling method is a method of chemically decomposing waste PET bottles and using them as chemical raw materials. Although it has the advantage of being able to be recycled semi-permanently, it has the disadvantage of being technically difficult and expensive.

Accordingly, the chemical recycling method has not yet been commercialized.

The mechanical recycling method is a method of melting and recycling PET bottles, and is the optimal method in terms of cost, but has the disadvantage of requiring thorough sorting.

The thermal recycling method reuses waste PET bottles as a thermal energy source, and has the disadvantage of not being able to use resources repeatedly and generating carbon dioxide during combustion.

Currently, the mechanical recycling method described above is the most widely used recycling method for PET bottles.

However, when PET bottles are simply melt-molded, it is difficult to use the recycled PET chips for polyester long fibers (filament yarn) due to deterioration of physical properties, color discoloration, and uneven dyeing.

In other words, PET chips recycled by conventional methods have low intrinsic viscosity (IV: Intrinsic Viscosity) and low purity, so they are mainly used for polyester short fibers, packaging sheets, etc., long fibers, new PET bottles, and PET sheets for vacuum forming. , there is a problem that it is unsuitable for reuse as a raw material for trays, cups, etc.

Meanwhile, as a result of searching for prior art related to recycling of PET bottles, a number of patent documents were searched, some of which are introduced as follows.

Patent Document 1 includes wet grinding and drying a polyester bottle body that has undergone a pretreatment process to form polyester flakes; Primary sorting of the polyester flakes by wind power and specific gravity difference; Forming polyester powder by wet grinding and drying the first selected polyester flakes; Secondary screening of the polyester powder by wind power and specific gravity difference; and melting the secondarily selected polyester powder and molding it into pellets.

Patent Document 1 above is a technology that uses existing PET flakes to regenerate them into polyester staple fibers.

And Patent Document 2 includes an input step of introducing a compressed PET bottle, a sorting step of dismantling the PET bottle compressed and introduced in the input step, separating foreign substances attached to the PET bottle, and simultaneously sorting the PET bottles by color, and A pulverizing step in which PET chips are formed by pulverizing them to a certain size after the selection is completed in the sorting step; a washing step in which foreign substances, label bonds, and chemicals are removed from the PET chips pulverized in the pulverizing step using cold water and hot water; Disclosed is a PET bottle recycling method comprising a drying step for removing moisture and foreign substances remaining in the PET chips washed in the washing step, and a dust collection section for collecting and removing contaminants generated in the selecting step, crushing step, washing step, and drying step. I'm doing it.

Patent Document 2 above is a technology for simply selecting used PET bottles, and does not disclose a technology for recycling PET bottle flakes into products with higher added value.

Patent Document 3 is a step of injecting the pulverized PET bottle into water and separating the pulverized PET from the components of the cap or cap retainer, label, and bottom of the empty bottle with different specific gravity, and adding the separated PET pulverized material to a solvent with a high boiling point. A step of removing labels and labeling adhesive components contained in the PET pulverized product by stirring during heating, and adding normal hexane as a low boiling point solvent to the PET pulverized material from which the labels and labeling adhesive components have been removed, thereby adding PET during heating and stirring. A PET recovery and regeneration method is disclosed, which consists of removing residual solvents attached to the pulverized material.

Patent Document 3 is limited to a method of recovering pelletized pure PET.

Korean Patent Publication No. 10-2011-0075097 (published on July 6, 2011) Korean Patent No. 10-0895529 (announced on April 30, 2009) Korean Patent Publication No. 10-2000-0072851 (published on December 5, 2000)

The present invention is intended to solve the problems of the prior art described above, and its purpose is to enable PET chips with low intrinsic viscosity and purity to be recycled into PET chips with high intrinsic viscosity and high purity.

Another purpose of the present invention is to enable reuse of PET chips with low intrinsic viscosity and purity as raw materials for manufacturing long fibers, high-strength polyester yarn, new PET bottles, PET sheets for vacuum forming, trays, cups, etc. .

In order to achieve the above object, the PET chip recycling method according to the present invention includes (a) preparing PET chips obtained by crushing PET bottles (S10), (b) heating and rotating the PET chips in a blender to produce a primary A step of causing crystallization (S20), (c) after step S20, a step of extruding the PET chip while heating it on an extrusion screw (S30), (d) after step S30, cutting the extruded PET raw material in water. Step (S40), (e) after step S40, separating water and PET chips, and then sorting PET chips of a certain size by a vibration separator (S50), (f) after step S50, PET chips Heating and rotating to achieve secondary crystallization and then solid-state polymerization reaction (S60), (g) drying and cooling the PET chip after S60 (S70), (h) S70 After the step, it is characterized in that it includes a step (S80) of packaging the recycled PET chip.

Additionally, in step S20, the PET chip is heated to 150 to 160°C in a blender and rotated at 800 to 1,000 rpm to increase the intrinsic viscosity.

In addition, in step S30, the PET raw material is extruded into a gel state close to the liquid state using a twin-type extrusion screw in which two screws are arranged side by side.

Additionally, in step S30, the pressure inside the extrusion screw is maintained at 0.7 to 0.9 bar using a vacuum pump.

In addition, before step S40, the method further includes the step of removing foreign substances using a screen changer and a polymer filter.

Additionally, in step S40, the purified water is heated to 70 to 80°C and supplied to the underwater jacket of the underwater cutting machine by a pump.

In addition, in step S40, the PET raw material passing through a plurality of nozzles arranged circumferentially is cut underwater using a rotating blade.

In addition, in step S50, water and PET chips are separated by a high-speed centrifuge, and then PET chips of a certain size are selected in a vibration separator.

In addition, in step S60, the PET chip is heated to 150 to 160°C in a blender and rotated at 800 to 1,000 rpm to secondary crystallization, thereby further increasing the intrinsic viscosity.

In addition, in step S60, nitrogen gas is supplied to the PET chip on which secondary crystallization has been completed and cooled to 40 to 50° C. to allow a solid-state polymerization reaction to occur.

In addition, the PET chip is cooled, foreign substances are collected, and then stored in a silo using a vacuum-type transfer loader.

And the PET chip regeneration device according to the present invention includes a primary crystallization unit that heats and rotates the pulverized PET chips to achieve primary crystallization, and an extrusion unit that extrudes the primary crystallized PET chips while heating them with an extrusion screw. and an underwater cutting unit that cuts the PET raw material that has passed through the extrusion unit underwater, and a secondary crystallization and solid phase polymerization reaction that causes secondary crystallization by rotating the cut PET chips while heating them. It is composed of a joint unit, a drying unit for drying and cooling the PET chips on which secondary crystallization has been completed, a storage silo for storing the dried PET chips, and a packer for packaging the recycled PET chips stored in the storage silo. It is characterized by being

In addition, the primary crystallization unit includes a mixer equipped with a rotating impeller, and is characterized in that the intrinsic viscosity of the PET chip is increased by friction of the high-speed rotation of the impeller.

Additionally, the extrusion unit is characterized in that a vacuum pump is provided to maintain the inside of the extrusion screw in a vacuum state.

In addition, the extrusion screw provided in the extrusion unit is characterized in that it is constructed in a prefabricated manner in which a plurality of unit extrusion screws are sequentially assembled.

In addition, each unit extrusion screw of the extrusion screw is characterized in that the shape and pitch of the rotating blades are configured differently.

In addition, the extrusion screw is characterized in that it is configured as a twin type in which two extrusion screws are arranged in parallel and rotate in the same direction.

Additionally, a heater and a gas discharge unit are further provided on the outer surface of the extrusion screw.

In addition, the outer surface of the extrusion screw is further characterized by a viewing window through which the extrusion state of the PET raw material can be visually confirmed.

In addition, a first screen changer, a first gear pump, a second screen changer, and a second gear pump are arranged in order on the rear line of the extrusion unit.

In addition, the first screen changer is composed of 100 to 200 mesh, and the second screen changer is composed of 200 to 300 mesh.

In addition, a polymer filter of 600 to 700 mesh is provided in the rear line of the second gear pump.

In addition, at the rear line of the polymer filter, an underwater jacket is provided that sprays purified water from the bottom to the top, and in the underwater jacket, PET raw materials passing through a plurality of nozzles arranged in a circumferential shape are sprayed by a rotating blade. It is characterized by cutting.

In addition, a centrifuge is provided at the rear line of the underwater cutting unit to separate water and PET chips.

In addition, the rear line of the centrifuge is characterized by a vibration separator that sorts PET chips of a certain size.

In addition, the secondary crystallization and solid phase polymerization section includes a second rotating section that heats and rotates the PET chip, a solid phase polymerization section that causes the solid phase polymerization reaction to occur inside the rotating drum, and a nitrogen tank for injecting nitrogen gas into the rotating drum. It is characterized by being composed of a.

In addition, a filter for collecting foreign substances is further provided at the outlet of the drying unit.

In addition, the PET chips that have passed through the drying unit are stored in a storage silo by a vacuum-type transfer loader.

In addition, a packer is provided at the bottom of the storage silo to automatically pack a certain amount of recycled PET chips.

According to the present invention, it is possible to manufacture PET chips with high intrinsic viscosity and high purity using PET chips with low intrinsic viscosity and purity.

In addition, PET chips with low intrinsic viscosity and purity can be used as raw materials for long fibers, high-strength polyester yarn, new PET bottles, PET sheets for vacuum forming, trays, and cups.

1 is a flow chart showing a PET chip recycling method according to the present invention.
Figure 2 is a plan view of the PET chip recycling device according to the present invention.
Figure 3 is a front view of the PET chip recycling device according to the present invention.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the attached drawings.

As used herein, PET chips refer to finely crushed PET bottles or pellets recycled according to the present invention.

And PET raw material means that the PET chip is heated to become a liquid gel.

<How to recycle PET chips>

As shown in Figure 1, the PET chip recycling method according to the present invention includes (a) preparing PET chips obtained by crushing PET bottles (S10), (b) heating and rotating the PET chips in a blender to obtain 1 A step of allowing secondary crystallization (S20), (c) after step S20, a step of extruding the PET chip while heating it on an extrusion screw (S30), (d) after step S30, cutting the extruded PET raw material in water. step (S40), (e) after step S40, separating water and PET chips, and then sorting PET chips of a certain size by a vibration separator (S50), (f) after step S50, PET chips heating and rotating to achieve secondary crystallization, followed by a solid-state polymerization reaction (S60), (g) drying and cooling the PET chip after step S60 (S70), and recycling PET chips. It includes a packaging step (S80).

In step S20, the PET chip is heated to 150 to 160°C in a blender and the impeller is rotated at 800 to 1,000 rpm to increase intrinsic viscosity.

When the PET chip is placed in a blender and heated and rotated, the temperature of the PET chip gradually increases due to friction generated by high-speed rotation.

And crystallization begins at 100℃ due to heat, and crystallization is completed at 150℃ ~ 160℃. Therefore, it is desirable to heat the PET chip to 150°C to 160°C.

When the temperature of the PET chip reaches about 150°C, a so-called yellowing phenomenon occurs in which the chips stick together before crystallization. The impeller rotates at high speed to prevent this yellowing phenomenon.

Once the crystallization of the PET chip is complete, heating is stopped and the rotation speed of the impeller is automatically adjusted to lower the temperature inside the mixer to 120°C.

After the first crystallization step is completed, the PET chip is extruded using a twin-type extrusion screw with two screws arranged side by side. At this time, the PET chip is extruded in a gel state close to liquid.

And in step S30, the pressure inside the extrusion screw is maintained at 0.7 to 0.9 bar using a vacuum pump.

By maintaining a vacuum state by applying a pressure of 0.7 to 0.9 bar inside the extrusion screw, the yellowing phenomenon of coagulation of raw materials can be suppressed and the intrinsic viscosity can be additionally increased. Additionally, moisture and gases inside the extrusion screw are removed.

On the other hand, if the pressure inside the extrusion screw exceeds 0.9 bar, it is undesirable because it becomes difficult to form an ideal vacuum state.

And before step S40, foreign substances are removed using a screen changer and polymer filter.

Next, in step S40, the PET raw material that has passed through the extrusion unit is cut underwater.

To describe the cutting step in more detail, the PET raw material that has passed through the extrusion unit is supplied into the underwater jacket 31 through a plurality of nozzles (not shown) arranged circumferentially. Here, the diameter of the nozzle is preferably 3 mm.

Additionally, a blade rotating at high speed is provided inside the underwater jacket 31 to cut the PET raw material passing through the nozzle into pellets of a certain size.

At this time, the purified water is heated to 70-80°C and cut by spraying it from the lower part of the underwater jacket 31.

If the temperature of the purified water is below 70℃, there is a risk that the nozzle through which PET raw materials are discharged may be clogged, and if the temperature of the water is above 80℃, the cooling effect during cutting of raw materials performed at about 270℃ will be reduced.

And in step S50, water and PET chips are separated by a high-speed centrifuge, and then PET chips of a certain size are selected in a vibration separator.

In the vibrating sorter, only circular chips with a diameter of 3 mm are selected and used, and other chips are separated and used for other purposes.

And in step S60, the PET chip is secondarily crystallized by heating it in a blender to 150 to 160°C and rotating it at 800 to 1,000 rpm. As a result, the intrinsic viscosity of PET chips further increases.

In addition, in step S60, nitrogen gas is supplied to the PET chip on which secondary crystallization has been completed and cooled to 40 to 50° C. to allow a solid-state polymerization reaction to occur.

And in step S70, after drying the PET chip, foreign substances are collected by a filter and then stored in a silo by a vacuum-type transfer loader.

PET chips stored in silos are automatically packaged and shipped in plastic bags in a certain amount by the packer.

<PET chip regeneration device>

Next, the structure of the PET chip recycling device according to the present invention will be described.

As shown in FIGS. 2 and 3, the PET chip regeneration device according to the present invention includes a primary crystallization unit 10 that heats and rotates pulverized PET chips to achieve primary crystallization, and An extrusion unit 20 that extrudes chips while heating them with an extrusion screw, an underwater cutting unit 30 that cuts the PET raw material that has passed through the extrusion unit 20 underwater, and the cut PET chips are heated and rotated. A secondary crystallization and solid-state polymerization section 40 that allows secondary crystallization to occur and then a solid-state polymerization reaction occurs, a drying section 50 that dries and cools the PET chips on which secondary crystallization has been completed, and It is configured to include a storage silo 60 for storing PET chips, and a packer 70 for packaging the recycled PET chips stored in the storage silo 60.

The primary crystallization unit 10 is comprised of a mixer equipped with a rotating impeller, and heats the PET chips introduced into the mixer while increasing the intrinsic viscosity of the PET chips due to high-speed rotation friction of the impeller.

PET chips on which primary crystallization has been completed are transferred to the hopper 21 of the extrusion unit 20 by the first transfer loader 12. The first transfer loader 12 is preferably composed of a transfer screw.

The extrusion unit 20 is a device for extruding PET chips into a gel state close to liquid, and is equipped with a vacuum pump 23 to maintain the inside of the extrusion screw 22 in a vacuum state.

In addition, the extrusion screw 22 is preferably constructed in a prefabricated manner in which a plurality of unit extrusion screws are assembled one after another.

In addition, it is preferable that each unit extrusion screw of the extrusion screw 22 has different shapes and pitches of rotary blades.

Due to the above structure, the extrusion screw can be easily replaced depending on the type of raw material being extruded.

In addition, the extrusion screw 22 is preferably configured as a twin type in which two extrusion screws are arranged in parallel and rotate in the same direction.

By using the twin-type extrusion screw 22, high-quality PET chips can be manufactured by increasing the density of the extruded PET raw material.

In addition, it is preferable that the outer surface of the extrusion screw 22 is further provided with a heater, a gas outlet, and a viewing window through which the extrusion state of the PET raw material can be visually confirmed.

And in the rear line of the extrusion unit 20, a first screen changer 24, a first gear pump 25, a second screen changer 26, and a second gear pump 27 are arranged in order.

The first gear pump 25 and the second gear pump 27 serve to prevent the pressure from decreasing when the PET raw material is transferred from the end of the extrusion screw 22 to the underwater cutting unit 30. Do it.

Additionally, the first screen changer 24 is preferably composed of 100 to 200 mesh, and the second screen changer 26 is preferably composed of 200 to 300 mesh.

Although not shown in the drawing, it is preferable that a third screen changer is further provided behind the second screen changer 26.

In this case, the third screen changer is preferably composed of 300 to 400 mesh.

In addition, it is preferable that a polymer filter 28 of 600 to 700 mesh is provided in the rear line of the second gear pump 27.

By using the above-described first screen changer 24, second screen changer 26, and polymer filter 28, various foreign substances contained in the PET raw material extruded in a form close to liquid can be filtered out. This can improve the purity and quality of PET chips.

And at the rear line of the polymer filter 28, an underwater cutting unit 30 is provided to cut the gel-like PET raw material that has passed through the filters to a certain length in water.

The underwater cutting unit 30 includes an underwater jacket 31 supplied with purified water and a rotating blade (not shown) for cutting the gel-like PET raw material passing through a nozzle (not shown). do.

The underwater jacket 31 receives water heated to 70 to 80° C. from a water pump (not shown) through a water supply line 31a.

Here, the upper part of the underwater jacket 31 is connected to the centrifuge 33 through a discharge line 31b.

And the rotating blade is radially disposed at the end of the cutter and rotates at high speed, cutting the PET raw material coming out through a plurality of nozzles arranged in a circumferential shape to a certain length.

At this time, water is sprayed from the bottom of the rotary cutter to the top through the water supply line (31a) using a water pump.

Then, the PET raw material heated to about 270°C and discharged through the nozzle is momentarily cooled by water and cut by a rotating blade.

PET chips cut to a certain length by a rotating blade move to the centrifuge 32 through the discharge line 31b along with water sprayed through the water supply line 31a.

The centrifuge 32 separates PET chips and water, and the separated PET chips move to the top of the centrifuge 32 and are then discharged to the vibration separator 33 through the chip discharge port 32a.

The vibration sorter 33 sorts chips with a diameter of 3 mm, and separates chips of other sizes for other purposes.

The PET chips sorted in the vibration sorter (33) are transferred to the secondary crystallization and solid phase polymerization unit (40) by the second transfer loader (41).

The secondary crystallization and solid-state polymerization unit 40 includes a second rotating unit 42 that heats and rotates the PET chip, a rotating drum 43 that causes the solid-state polymerization reaction to occur, and the second rotating unit 42. It is composed of a nitrogen tank 44 for introducing nitrogen gas.

The second rotating unit 42 causes secondary crystallization of the PET chip in the same manner as the above-described first rotating unit 41.

Then, the rotating drum 43 is rotated while injecting nitrogen gas, so that the PET chip is cooled to 40 to 50° C. and a solid-state polymerization reaction occurs.

PET chips on which secondary crystallization and solid-state polymerization reactions have been completed are transferred to the drying unit 50 by the third transfer loader 51.

In addition, it is preferable that a filter for collecting foreign substances is further provided at the outlet of the drying unit 50.

PET chips that have passed through the drying unit 50 are stored in the storage silo 60 by the fourth transfer loader 61. The fourth transfer loader 61 is preferably configured as a vacuum type transfer loader.

A packer 70 is provided at the bottom of the storage silo 60 to automatically pack a certain amount of PET chips into plastic bags.

Conventional PET chip recycling methods have limitations in improving the intrinsic viscosity and purity of PET, so recycled PET chips are used as raw materials for high-quality long fibers, new PET bottles, PET sheets for vacuum forming, trays, and cups. It's difficult to do.

According to the present invention, pulverized PET chips can be regenerated into PET chips with high intrinsic viscosity and high purity through the steps of primary crystallization, extrusion, underwater cutting, secondary crystallization, and solid-state polymerization.

As a result, recycled PET chips can be reused as raw materials for manufacturing long fibers, new PET bottles, PET sheets for vacuum forming, trays, and cups.

The above has illustratively described preferred embodiments of the present invention, and the scope of the present invention is not limited to the specific embodiments described above. Anyone skilled in the art to which the present invention pertains will understand that various modifications and changes can be made without departing from the scope of the technical idea of the present invention.

10: primary crystallization unit 11: first rotation unit
12: First transfer loader (Loader) 20: Extrusion unit
21: Hopper 22: Extrusion Screw
23: Vacuum pump
24: 1st Screen Changer
25: 1st gear pump 26: 2nd screen changer
27: Second gear pump 28: Polymer Filter
30: Underwater cutting part
31: Underwater Jacket
31a: water supply line 31b: discharge line
32: centrifuge 32a: chip outlet
33: Vibration separator 40: Secondary crystallization and solid phase polymerization unit
41: second transfer loader 42: second rotating unit
43: Rotating drum (Drum) 44: Nitrogen tank (Tank)
50: Drying unit 51: Third transfer loader
60: Storage silo 61: 4th transfer loader
70: Packer

Claims (29)

delete delete delete delete delete delete delete delete delete delete delete In the PET chip regeneration device for improving the intrinsic viscosity and purity of PET chips obtained by crushing PET bottles,
A primary crystallization unit 10 that heats and rotates the pulverized PET chips to achieve primary crystallization,
An extrusion unit 20 that extrudes the primary crystallized PET chip while heating it with an extrusion screw 22,
An underwater cutting unit (30) that cuts the PET raw material that has passed through the extrusion unit (20) underwater,
A secondary crystallization and solid-state polymerization unit 40 that heats and rotates the cut PET chip to achieve secondary crystallization, and then causes a solid-state polymerization reaction to occur;
A drying unit 50 for drying and cooling PET chips on which secondary crystallization has been completed;
A storage silo (60) for storing dried PET chips,
It is configured to include a packer 70 for packaging the recycled PET chips stored in the storage silo 60,
The primary crystallization unit 10 is comprised of a mixer equipped with a rotating impeller, and increases the intrinsic viscosity of the PET chip by friction of the high-speed rotation of the impeller,
PET chips on which primary crystallization has been completed are transferred to the hopper 21 of the extrusion unit 20 by the first transfer loader 12,
The extrusion unit 20 is provided with a vacuum pump 23 to maintain the inside of the extrusion screw 22 in a vacuum state, so that the PET chip is extruded in a gel state close to the liquid state,
The extrusion screw 22 provided in the extrusion unit 20 is constructed in a prefabricated manner in which a plurality of unit extrusion screws are sequentially assembled,
Each unit extrusion screw of the extrusion screw 22 has different shapes and pitches of rotary blades,
The extrusion screw 22 is composed of a twin type in which two extrusion screws are arranged in parallel and rotate in the same direction,
A heater and a gas outlet are further provided on the outer surface of the extrusion screw 22,
A viewing window is further provided on the outer surface of the extrusion screw 22 to visually check the extrusion state of the PET raw material,
On the rear line of the extrusion unit 20, a first screen changer 24, a first gear pump 25, a second screen changer 26, and a second gear pump 27 are arranged in order,
The first screen changer 24 is composed of 100 to 200 mesh, and the second screen changer 26 is composed of 200 to 300 mesh,
A third screen changer composed of 300 to 400 mesh is further provided behind the second screen changer 26,
A polymer filter (28) of 600 to 700 mesh is provided in the rear line of the second gear pump (27),
At the rear line of the polymer filter 28, an underwater cutting unit 30 is provided to cut the gel-like PET raw material that has passed through the filter to a predetermined length in water,
The underwater cutting unit 30 includes an underwater jacket 31 supplied with purified water and a rotating blade for cutting the gel-like PET raw material passing through the nozzle,
The underwater jacket 31 receives water heated to 70 to 80°C from a water pump through a water supply line 31a,
The upper part of the underwater jacket 31 is connected to the centrifuge 33 by a discharge line 31b,
When the rotating blade, which is radially disposed at the end of the cutter and rotates at high speed, cuts the PET raw material coming out through a plurality of circumferentially arranged nozzles to a certain length, the cutter is supplied through the water supply line (31a) by a water pump. Water is sprayed from the bottom to the top,
PET chips cut to a certain length by a rotating blade move to the centrifuge 32 through the discharge line 31b together with the water sprayed through the water supply line 31a.
The centrifuge 32 separates PET chips and water, and the separated PET chips move to the top of the centrifuge 32 and are then discharged to the vibration separator 33 through the chip outlet 32a.
The PET chips selected in the vibration sorter (33) are transferred to the secondary crystallization and solid phase polymerization unit (40) by the second transfer loader (41),
The secondary crystallization and solid phase polymerization unit 40,
A second rotating part 42 that heats and rotates the PET chip,
A rotating drum 43 that allows a solid-state polymerization reaction to occur inside,
It is configured to include a nitrogen tank (44) for introducing nitrogen gas into the rotating drum (43),
The rotary drum 43 is rotated while injecting nitrogen gas, so that the PET chip is cooled to 40 to 50° C. and a solid-state polymerization reaction occurs,
PET chips for which secondary crystallization and solid-state polymerization reactions have been completed are transferred to the drying unit 50 by the third transfer loader 51,
A filter for collecting foreign substances is further provided at the outlet of the drying unit 50,
PET chips that have passed through the filter are stored in the storage silo (60) by a vacuum-type transfer loader (61),
A PET chip recycling device, characterized in that a packer (70) is provided at the lower part of the storage silo (60) to automatically pack a certain amount of recycled PET chips. delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete

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