Recovery production line for chemical recovery of waste bottle flakes

Abstract

The invention provides a recovery production line for chemical recovery of waste bottle flakes, which comprises a raw material tank and a material mixing kettle for receiving the waste bottle flakes in the raw material tank; the spiral homogenizing kettle is used for crushing and uniformly mixing the waste bottle flakes; the double-screw melting and depolymerizing equipment is connected with the spiral homogenizing kettle through a feeding hole, and is used for heating and melting the waste bottle flakes and adding ethylene glycol to depolymerize so as to produce BHET (butylated hydroxytoluene); the integrated esterification reactor is used for carrying out reaction on BHET and excessive ethylene glycol and is used for producing ester compounds; and the polycondensation kettle is used for removing a by-product ethylene glycol in the ester compound, so that high-purity pet is produced. According to the waste bottle chip recycling device, integrated recycling of waste bottle chips is achieved, meanwhile, excessive ethylene glycol and water can be recycled and reused conveniently, operation is easy, and the automation degree is high.

Description

Technical Field

[0001] This invention relates to the field of PET recycling technology, and more particularly to a recycling production line for chemically recycling waste bottle flakes. Background Technology

[0002] PET is the abbreviation for polyethylene terephthalate, a widely used thermoplastic polyester polymer material, commonly known as polyester resin. It is produced by transesterification of dimethyl terephthalate with ethylene glycol, or by esterification of terephthalic acid with ethylene glycol to synthesize diethyl terephthalate, followed by a polycondensation reaction. Together with PBT, they are collectively referred to as thermoplastic polyesters or saturated polyesters.

[0003] When using PET for spinning or pelletizing, a continuous one-head-two-tail polyester unit is usually adopted, with an 80,000-ton primary esterification capacity, two 40,000-ton tails (equipped with secondary esterification, pre-condensation, and final condensation respectively), one melt-spinning line (B line), and one pelletizing line (A line). It is difficult to recycle waste bottle flakes and produce PET yarn or PET pellets, resulting in high production costs. Summary of the Invention

[0004] The present invention aims to provide a recycling production line for chemically recycling waste bottle flakes to overcome or at least partially solve the above-mentioned problems.

[0005] To achieve the above objectives, the technical solution of the present invention is specifically implemented as follows: This invention provides a recycling production line for chemically recycling waste bottle flakes, including a raw material tank, and further comprising: A mixing vessel is used to receive waste bottle flakes from a raw material tank and to pre-treat the waste bottle flakes.

[0006] A spiral homogenizing reactor is used to receive pre-treated waste bottle flakes and to crush and homogenize them.

[0007] A twin-screw melting and depolymerization equipment is connected to a spiral homogenizing reactor through a feed inlet and receives waste bottle flakes. The waste bottle flakes are heated and melted, and ethylene glycol is added to depolymerize them to produce BHET.

[0008] An integrated esterification reactor for reacting BHET with excess ethylene glycol to produce ester compounds.

[0009] A polycondensation reactor, the inlet of which is connected to the outlet of an integrated ester reactor, is used to remove ethylene glycol, a byproduct of ester compounds, thereby producing high-purity PET.

[0010] As a further aspect of the present invention, a first filter separator is also included, wherein the inlet of the filter separator is connected to the outlet of the twin-screw melt depolymerization device, and is used to separate and filter minute impurities in the BHET after melt depolymerization.

[0011] As a further aspect of the present invention, a second filter separator is also included, wherein the inlet of the filter separator is connected to the outlet of the polycondensation reactor, for further removal of impurities in the molten petroleum.

[0012] As a further embodiment of the present invention, the right end of the twin-screw melting and depolymerization device is connected to a conveying pipe, which transversely penetrates the condenser shell. A movable plate is installed at the top of the conveying pipe, and the activated carbon plate is located inside the condenser shell. A vacuum pump is installed at the top of the condenser shell, the outlet of the vacuum pump is connected to one end of a return pipe, and the other end of the return pipe is connected to the lower part of the condenser shell. A drain pipe is installed at the bottom of the condenser shell.

[0013] As a further embodiment of the present invention, a heat insulation plate is also fixedly installed inside the condenser shell. The heat insulation plate is disposed between the condenser shell and the conveying pipe, and divides the interior of the condenser shell into upper and lower cavities.

[0014] As a further embodiment of the present invention, the interior of the condensation shell is also equipped with a plurality of condensation titanium tubes and a support plate. The condensation titanium tubes are mounted on the support plate. The left and right ends of the condensation titanium tubes pass through the condensation shell and are connected to external cooling water and a delivery pump. The delivery pump circulates the cooling water through the condensation titanium tubes.

[0015] This invention provides a recycling production line for chemically recycling waste bottle flakes. The advantages are: it realizes integrated recycling of waste bottle flakes, and also facilitates the recycling and reuse of excess ethylene glycol and water. It is simple to operate, highly automated, and reduces the cost of use. Attached Figure Description

[0016] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the following description of the embodiments will be briefly introduced. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is a flowchart of the present invention.

[0018] Figure 2 This is a cross-sectional view of the condenser shell in this invention.

[0019] Figure 3This is a side view of the condenser housing in this invention.

[0020] Figure 4 This is a flowchart of a continuous polyester plant with one start and two ends.

[0021] In the diagram: 1. Raw material tank; 2. Mixing vessel; 3. Spiral homogenizing vessel; 4. Twin-screw melting and depolymerization equipment; 5. First filter separator; 6. Integrated esterification reactor; 7. Polycondensation vessel; 8. Second filter separator; 9. Condensation shell; 10. Vacuum pump; 11. Return pipe; 12. Condensation titanium tube; 13. Support plate; 14. Insulation plate; 41. Conveying pipe; 42. Activated carbon plate; 91. Drainage pipe. Detailed Implementation

[0022] Exemplary embodiments of the present disclosure will now be described in more detail with reference to the accompanying drawings. While exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art.

[0023] See Figure 1-3 The present invention provides a recycling production line for chemically recycling waste bottle flakes, comprising a raw material tank 1, and further comprising: Mixing vessel 2 is used to receive waste bottle flakes from raw material tank 1 and to pre-treat the waste bottle flakes.

[0024] Spiral homogenizer 3 is used to receive waste bottle flakes after preliminary pretreatment and to crush and homogenize the waste bottle flakes.

[0025] The twin-screw melting and depolymerization equipment 4 is connected to the spiral homogenizing kettle 3 through the feed port and receives waste bottle flakes. The waste bottle flakes are heated and melted and ethylene glycol is added to depolymerize them to produce BHET.

[0026] The integrated esterification reactor 6 is used to react BHET with excess ethylene glycol to produce ester compounds.

[0027] Polycondensation reactor 7 has its inlet connected to the outlet of the integrated ester reactor. It is used to remove ethylene glycol, a byproduct of ester compounds, to produce high-purity PET.

[0028] It also includes a first filter separator 5, whose inlet is connected to the outlet of the twin-screw melt depolymerization device 4, for separating and filtering minute impurities in the BHET after melt depolymerization.

[0029] It also includes a second filter separator 8, whose inlet is connected to the outlet of the polycondensation reactor 7, for further removal of impurities from the molten pet.

[0030] In the process of using this invention, the waste bottle flakes placed in the raw material tank 1 are first sent to the mixing tank 2 for preliminary pretreatment to remove surface impurities. Then, the raw material is sent to the spiral homogenizing tank 3 to be crushed into small pieces and mixed evenly. Then, it is sent to the twin-screw melting and depolymerization equipment 4, where the raw material is squeezed and heated by the screw to melt it. Ethylene glycol is added to the twin-screw melting and depolymerization equipment 4 to depolymerize the raw material and produce BHET. The gaseous water and ethylene glycol are removed by the vacuum pump 10. Then, it is sent to the first filter separator 5 for initial filtration of impurities. Then, it passes through the integrated esterification reactor 6 to produce ester compounds. High-purity PET is produced in the polycondensation tank 7 and then passes through the second filter separator 8 for secondary impurity removal. Finally, it is sent to the spinning equipment and pelletizing equipment for spinning and pelletizing.

[0031] See Figure 2 and Figure 3 The right end of the twin-screw melting and depolymerization equipment 4 is connected to a conveying pipe 41, which runs horizontally through the condenser shell 9. A movable plate is installed on the top of the conveying pipe 41, and the activated carbon plate 42 is located inside the condenser shell 9. A vacuum pump 10 is installed at the top of the condenser shell 9. The outlet of the vacuum pump 10 is connected to one end of the return pipe 11, and the other end of the return pipe 11 is connected to the lower part of the condenser shell 9. A drain pipe 91 is installed at the bottom of the condenser shell 9.

[0032] A heat insulation plate 14 is also fixedly installed inside the condenser shell 9. The heat insulation plate 14 is located between the condenser shell 9 and the conveying pipe 41, and divides the interior of the condenser shell 9 into upper and lower cavities.

[0033] The condenser housing 9 is also equipped with multiple condenser titanium tubes 12 and a support plate 13. The condenser titanium tubes 12 are mounted on the support plate 13. The left and right ends of the condenser titanium tubes 12 pass through the condenser housing 9 and are connected to the external cooling water and the delivery pump. The delivery pump circulates the cooling water through the condenser titanium tubes 12.

[0034] In use, the present invention uses a vacuum pump 10 to draw gaseous water and ethylene glycol from the activated carbon plate 42 through the conveying pipe 41 and into the upper part of the condenser shell 9. The gaseous water and ethylene glycol are then sent into the lower cavity of the condenser shell 9 through the return pipe 11, where they come into contact with the condenser titanium tube 12 and liquefy the water and ethylene glycol. The liquefied water and ethylene glycol are then discharged through the drain pipe 91. The activated carbon plate 42 can absorb and purify ethylene glycol and other waste.

[0035] The above are merely embodiments of this application and are not intended to limit the scope of this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of the claims of this application.

Claims

1. A recycling production line for chemically recycling waste bottle flakes, comprising a raw material tank (1), characterized in that, Also includes: Mixing vessel (2), the mixing vessel (2) is used to receive waste bottle flakes in raw material tank (1) and to pre-treat the waste bottle flakes; Spiral homogenizing kettle (3), the spiral homogenizing kettle (3) is used to receive waste bottle flakes after preliminary pretreatment, and is used to crush and mix the waste bottle flakes; The twin-screw melting and depolymerization equipment (4) is connected to the spiral homogenizing kettle (3) through the feed port and receives waste bottle flakes. The waste bottle flakes are heated, melted and depolymerized by adding ethylene glycol to produce BHET. An integrated esterification reactor (6) is used to react BHET with excess ethylene glycol to produce ester compounds. Polycondensation reactor (7), the inlet of which is connected to the outlet of the integrated ester reactor, is used to remove ethylene glycol, a byproduct of ester compounds, thereby producing high-purity PET.

2. The recycling production line for chemically recycling waste bottle flakes according to claim 1, characterized in that, It also includes a first filter separator (5), the inlet of which is connected to the outlet of the twin-screw melt depolymerization device (4), for separating and filtering minute impurities in the BHET after melt depolymerization.

3. The recycling production line for chemically recycling waste bottle flakes according to claim 1, characterized in that, It also includes a second filter separator (8), the inlet of which is connected to the outlet of the polycondensation vessel (7) for further removal of impurities from the molten pet.

4. The recycling production line for chemically recycling waste bottle flakes according to claim 1, characterized in that, The right end of the twin-screw melting and depolymerization device (4) is connected to a conveying pipe (41), which runs horizontally through the condenser shell (9). A movable plate is installed on the top of the conveying pipe (41), and an activated carbon plate (42) is located inside the condenser shell (9). A vacuum pump (10) is installed at the top of the condenser shell (9). The outlet of the vacuum pump (10) is connected to one end of a return pipe (11), and the other end of the return pipe (11) is connected to the lower part of the condenser shell (9). A drain pipe (91) is installed at the bottom of the condenser shell (9).

5. A recycling production line for chemically recycling waste bottle flakes according to claim 4, characterized in that, A heat insulation plate (14) is also fixedly installed inside the condenser shell (9). The heat insulation plate (14) is located between the condenser shell (9) and the conveying pipe (41) and divides the interior of the condenser shell (9) into upper and lower cavities.

6. A recycling production line for chemically recycling waste bottle flakes according to claim 5, characterized in that, The condenser shell (9) is also equipped with multiple condenser titanium tubes (12) and a support plate (13). The condenser titanium tubes (12) are mounted on the support plate (13). The left and right ends of the condenser titanium tubes (12) pass through the condenser shell (9) and are connected to external cooling water and a delivery pump. The delivery pump circulates the cooling water through the condenser titanium tubes (12).

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