A system for upgrading PBT plastic to PBS biodegradable plastic and co-producing hydrogen.

Abstract

This invention discloses a system for upgrading PBT plastic to PBS biodegradable plastic and co-producing hydrogen. The system comprises a waste PBT pretreatment system, an electrolytic water hydrogen production coupled oxidation system, and a PBS esterification polymerization system connected in sequence. The waste PBT pretreatment system includes a waste PBT pulverizing device, a waste PBT degradation device, and a degradation product separation device connected in sequence. The electrolytic water hydrogen production coupled oxidation system includes an electrolytic water hydrogen production coupled oxidation reactor, which is electrically connected to a power supply system. The inlet of the electrolytic water hydrogen production coupled oxidation reactor is connected to an electrolyte mixing device. The PBS esterification polymerization system includes an esterification condensation reactor and a PBS recovery tank. This invention achieves efficient utilization of various substances in the process of upgrading waste plastics to biodegradable plastics, resulting in socio-economic benefits and providing a practical and feasible green and sustainable new approach for waste plastic recycling and utilization systems.

Description

Technical Field

[0001] This utility model belongs to the field of waste material recycling technology, specifically relating to a system for upgrading PBT plastic to PBS biodegradable plastic and co-producing hydrogen. Background Technology

[0002] Polybutylene terephthalate (PBT) is one of the five major engineering plastics, widely used in electronics, automotive parts, and other fields. As an aromatic polyester, PBT is difficult to decompose in the natural environment, causing serious environmental problems. To achieve the strategic goal of a sustainable plastics economy, the environmentally friendly treatment of waste PBT is particularly important. (Polymer 307, 2024, 127326.) Currently, most waste plastics are still disposed of through landfill or incineration to partially recover the stored energy in the short term, but this cannot create lasting economic value or significantly reduce resource consumption; it may even emit carbon dioxide and other harmful gases, negatively impacting the environment. Mechanical recycling of used plastics often leads to degradation of material properties, forming so-called "downcycle" materials, whose quality and utility are reduced. Chemical recycling achieves sustainable and environmentally friendly development in the polymer industry by converting waste plastics into high-purity monomers and repolymerizing them. However, existing equipment cannot achieve the chemical recycling of PBT. Utility Model Content

[0003] This invention is proposed to overcome the shortcomings of the existing technology, and its purpose is to provide a system for upgrading PBT plastic to PBS degradable plastic and co-producing hydrogen.

[0004] This utility model is achieved through the following technical solution:

[0005] A system for upgrading PBT plastic to PBS biodegradable plastic and co-producing hydrogen includes a waste PBT pretreatment system, an electrolytic water hydrogen production coupled oxidation system, and a PBS esterification polymerization system connected in sequence. The waste PBT pretreatment system includes a waste PBT pulverizing device, a waste PBT degradation device, and a degradation product separation device connected in sequence. The liquid product outlet of the degradation product separation device is connected to a liquid product separation and purification device, and the outlet of the liquid product separation and purification device is connected to a liquid storage device. The electrolytic water hydrogen production coupled oxidation system includes an electrolytic water hydrogen production coupled oxidation reactor, which is electrically connected to a power supply system. The inlet of the electrolytic water hydrogen production coupled oxidation reactor is connected to an electrolyte mixing device. The inlet of the electrolyte mixing device is connected to the liquid storage device. The PBS esterification polymerization system includes an esterification condensation reactor and a PBS recovery tank. The inlet of the esterification condensation reactor is connected to the outlet of a solid storage device and the outlet of an electrolytic product storage device, respectively.

[0006] In the above technical solution, the liquid product outlet of the degradation product separation device is connected to the liquid product separation and purification device, the solid product outlet is connected to the drying device, and the outlet of the drying device is connected to the solid storage device.

[0007] In the above technical solution, the cathode outlet of the electrolytic water hydrogen production coupled oxidation reactor is connected to a gas-liquid separation device, and the gas outlet of the gas-liquid separation device is connected to a hydrogen collection device; the anode outlet of the electrolytic water hydrogen production coupled oxidation reactor is connected to an anode product storage device, and the outlet of the anode product storage device is connected to an electrolytic product separation device; the KOH separated by the electrolytic product separation device enters an alkali recovery device, and the separated electrolytic products enter the electrolytic product storage device.

[0008] In the above technical solution, the PBS esterification polymerization system further includes a liquid-solid separation device and a solvent recovery tank; the outlet of the esterification condensation reactor is connected to the inlet of the liquid-solid separation device; the liquid outlet of the liquid-solid separation device is connected to the solvent recovery tank, and the solid outlet is connected to the PBS recovery tank.

[0009] The beneficial effects of this utility model are: This utility model provides a system for upgrading PBT plastic to PBS biodegradable plastic and co-producing hydrogen, realizing the efficient utilization of various substances in the process of upgrading waste plastic to biodegradable plastic, which has certain social and economic benefits, and provides a practical and feasible green and sustainable new method for waste plastic recycling and utilization. Attached Figure Description

[0010] Figure 1 This is a schematic diagram of the structure of this utility model;

[0011] Figure 2 This is the infrared spectrum of the biodegradable plastic PBS in Application Example 1 of this utility model.

[0012] in:

[0013] 1. Waste PBT pretreatment system; 11. Waste PBT pulverizing device; 12. Waste PBT degradation device; 13. Degradation product separation device; 14. Liquid product separation and purification device; 15. Drying device; 16. Solid storage device; 17. Liquid storage device;

[0014] 2. Electrolysis of water to produce hydrogen coupled with oxidation system; 21. Electrolysis of water to produce hydrogen coupled with oxidation reactor; 22.

[0015] 23. Power supply system; 24. Electrolyte mixing device; 25. Gas-liquid separation device; 26. Hydrogen collection device; 27. Anode product storage device; 28. Electrolysis product separation device; 29. ​​Electrolysis product storage device;

[0016] 3. PBS esterification polymerization system; 31. Esterification condensation reactor; 32. Liquid-solid separation device; 33. Solvent recovery tank; 34. PBS recovery tank.

[0017] For those skilled in the art, other related figures can be obtained from the above figures without any creative effort. Detailed Implementation

[0018] To enable those skilled in the art to better understand the technical solution of this utility model, the technical solution of this utility model will be further described below with reference to the accompanying drawings and specific embodiments.

[0019] like Figure 1 As shown, a system for upgrading PBT plastic to PBS biodegradable plastic and co-producing hydrogen includes a waste PBT pretreatment system 1, an electrolysis water hydrogen production coupled oxidation system 2, and a PBS esterification polymerization system 3 connected in sequence.

[0020] The waste PBT pretreatment system 1 includes a waste PBT crushing device 11, a waste PBT degradation device 12, and a degradation product separation device 13 connected in sequence; the liquid product outlet of the degradation product separation device 13 is connected to a liquid product separation and purification device 15, and its solid product outlet is connected to a drying device 14; the outlet of the liquid product separation and purification device 15 is connected to a liquid storage device 17; the outlet of the drying device 14 is connected to a solid storage device 16.

[0021] In this embodiment, the waste PBT crushing device 11 is a plastic crusher; the waste PBT degradation device 12 is a reaction vessel; the degradation product separation device 13 is a filter; the liquid product separation and purification device 14 is a vacuum distillation reactor; and the drying device 15 is a heating dryer.

[0022] The water electrolysis hydrogen production coupled oxidation system 2 includes a water electrolysis hydrogen production coupled oxidation reactor 21, which is electrically connected to a power supply system 22. The inlet of the water electrolysis hydrogen production coupled oxidation reactor 21 is connected to an electrolyte mixing device 23. The cathode and anode inlets of the electrolyte mixing device 23 are connected to a liquid storage device 17.

[0023] The electrolytic water hydrogen production coupled oxidation system 2 also includes an alkali replenishment device 29 connected to the electrolyte mixing device 23;

[0024] In this embodiment, the electrolysis water hydrogen production coupled oxidation system 2 is a commercially available electrolysis system;

[0025] The alkali replenishment device 29 is an alkali raw material tank;

[0026] The cathode outlet of the electrolytic water hydrogen production coupled oxidation reactor 21 is connected to the gas-liquid separation device 24, and the gas outlet of the gas-liquid separation device 24 is connected to the hydrogen collection device 25; the anode outlet of the electrolytic water hydrogen production coupled oxidation reactor 21 is connected to the anode product storage device 26, and the outlet of the anode product storage device 26 is connected to the electrolytic product separation device 27. The KOH separated by the electrolytic product separation device 27 enters the alkali recovery device, and the separated electrolytic products enter the electrolytic product storage device 28.

[0027] The PBS esterification polymerization system 3 includes an esterification condensation reactor 31, a liquid-solid separation device 32, a solvent recovery tank 33, and a PBS recovery tank 34.

[0028] The inlet of the esterification condensation reactor 31 is connected to the outlet of the solid storage device 16 and the outlet of the electrolysis product storage device 28, respectively; the inlet of the liquid-solid separation device 32 is connected to the outlet of the esterification condensation reactor 31.

[0029] The liquid outlet of the liquid-solid separation device 32 is connected to the solvent recovery tank 33, and the solid outlet is connected to the PBS recovery tank 34.

[0030] The outlet of the solvent recovery tank 33 is connected to the inlet of the esterification condensation reactor 31.

[0031] The infrared spectrum of biodegradable plastic PBS obtained using the device of this application is as follows: Figure 2 As shown.

[0032] The working principle of this utility model:

[0033] This invention uses waste PBT as raw material and utilizes an electrolysis water hydrogen production system coupled with an organic oxidation system to electro-oxidize the PBT degradation product BDO to prepare SA monomer while simultaneously producing hydrogen. By further esterifying and polycondensing BDO and SA, a biodegradable PBS polymer is obtained. This invention constructs a renewable energy-driven system for regenerating waste non-biodegradable plastics into biodegradable plastics while simultaneously producing hydrogen, achieving a green and efficient upgrade and regeneration of waste plastics into biodegradable plastics.

[0034] Waste PBT pretreatment system: Using waste PBT as raw material, the waste PBT is mechanically crushed and pretreated, and then 1,4-butanediol (BDO) and terephthalic acid (TPA) are obtained after alcoholysis and separation purification.

[0035] Electrolysis of water to produce hydrogen coupled with oxidation system: The electrolytic cell is composed of an anode, a cathode catalyst and an electrolyte with a certain amount of BDO added. Under the condition of applying a certain voltage, BDO is oxidized to succinic acid (SA) at the anode, and hydrogen is produced at the cathode. The collected SA is further separated and purified.

[0036] PBS esterification polymerization system: BDO obtained from the waste PBT pretreatment system and SA obtained from the electrolysis of water to produce hydrogen coupled oxidation system are subjected to ester exchange polycondensation reaction to obtain biodegradable PBS polymer.

[0037] This invention utilizes renewable energy-driven electrocatalytic technology to oxidize waste PBT degradation product BDO to SA at the anode. The PBS obtained by further polymerization of BDO and SA can be used in food packaging, agricultural materials and other fields. At the same time, hydrogen is co-produced at the cathode, and the purity and efficiency of hydrogen production are comparable to those of traditional proton exchange membrane electrolysis (PEM) technology.

[0038] This invention proposes to first separate and purify PBT into terephthalic acid (TPA) and 1,4-butanediol (BDO) after alcoholysis. Then, BDO is oxidized to succinic acid (SA) at the anode of water electrolysis to produce hydrogen, while simultaneously generating hydrogen. The obtained BDO and SA are then subjected to esterification and polycondensation to obtain biodegradable plastic polybutylene succinate (PBS).

[0039] This invention not only solves the problem of PBT recycling by further converting it into biodegradable PBS and recycling TPA, thus realizing the high-value utilization of waste plastics, but also reduces the voltage of water electrolysis for hydrogen production, thereby improving the economic efficiency of the water electrolysis hydrogen production process.

[0040] Compared with other PBT recycling systems, this invention provides a new technological route for reducing waste accumulation and achieving a circular polymer economy through the chemical recycling of PBT. This invention also provides a highly economical new process system route for obtaining high-energy-density hydrogen by coupling organic oxidation reaction at the anode of water electrolysis to reduce the overall cell pressure of water electrolysis.

[0041] It should be noted that, unless otherwise specified, the embodiments and features described in these embodiments can be combined with each other.

[0042] In the description of this utility model, it should be understood that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating orientation or positional relationships based on the orientation or positional relationships shown in the accompanying drawings, are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model. Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, features defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of this utility model, unless otherwise stated, "a plurality of" means two or more.

[0043] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances. The applicant declares that the above description is only a specific embodiment of this utility model, but the protection scope of this utility model is not limited thereto. Those skilled in the art should understand that any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this utility model fall within the protection and disclosure scope of this utility model.

Claims

1. A system for upgrading PBT plastic to PBS degradable plastic with co-production of hydrogen gas, characterized in that: It includes a waste PBT pretreatment system (1), an electrolysis water hydrogen production coupled oxidation system (2), and a PBS esterification polymerization system (3) connected in sequence. The waste PBT pretreatment system (1) includes a waste PBT crushing device (11), a waste PBT degradation device (12), and a degradation product separation device (13) connected in sequence; the liquid product outlet of the degradation product separation device (13) is connected to a liquid product separation and purification device (15), and the outlet of the liquid product separation and purification device (15) is connected to a liquid storage device (17). The electrolysis hydrogen production coupled oxidation system (2) includes an electrolysis hydrogen production coupled oxidation reactor (21), which is electrically connected to a power supply system (22). The inlet of the electrolysis hydrogen production coupled oxidation reactor (21) is connected to an electrolyte mixing device (23). The inlet of the electrolyte mixing device (23) is connected to a liquid storage device (17). The PBS esterification polymerization system (3) includes an esterification condensation reactor (31) and a PBS recovery tank (34); the inlet of the esterification condensation reactor (31) is connected to the outlet of the solid storage device (16) and the outlet of the electrolytic product storage device (28), respectively.

2. The system for upgrading PBT plastic to PBS degradable plastic with co-production of hydrogen according to claim 1, characterized in that: The liquid product outlet of the degradation product separation device (13) is connected to the liquid product separation and purification device (15), and its solid product outlet is connected to the drying device (14). The outlet of the drying device (14) is connected to the solid storage device (16).

3. The system for upgrading PBT plastic to PBS degradable plastic with co-production of hydrogen according to claim 1, characterized in that: The cathode outlet of the electrolytic water hydrogen production coupled oxidation reactor (21) is connected to a gas-liquid separation device (24), and the gas outlet of the gas-liquid separation device (24) is connected to a hydrogen collection device (25). The anode outlet of the electrolytic water hydrogen production coupled oxidation reactor (21) is connected to an anode product storage device (26), and the outlet of the anode product storage device (26) is connected to an electrolytic product separation device (27). The KOH separated by the electrolytic product separation device (27) enters the alkali recovery device, and the separated electrolytic products enter the electrolytic product storage device (28).

4. The system for upgrading PBT plastic to PBS degradable plastic with co-production of hydrogen according to claim 1, characterized in that: The PBS esterification polymerization system (3) also includes a liquid-solid separation device (32) and a solvent recovery tank (33); the outlet of the esterification condensation reactor (31) is connected to the inlet of the liquid-solid separation device (32); the liquid outlet of the liquid-solid separation device (32) is connected to the solvent recovery tank (33), and the solid outlet is connected to the PBS recovery tank (34).

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