A recycling system and method for photovoltaic modules

Abstract

The application discloses a recycling system and method of photovoltaic modules, and belongs to the harmless and resourceful disposal technical field of retired photovoltaic modules. The recycling system of the photovoltaic modules comprises a pyrolysis furnace, a wet steam oxidation furnace and a cooling furnace; a discharge port of the pyrolysis furnace is connected with a feeding port of the wet steam oxidation furnace, and a discharge port of the wet steam oxidation furnace is connected with a feeding port of the cooling furnace; and a molten salt heating pipe is arranged in the pyrolysis furnace in a circumferential direction. The application further provides a recycling method of the photovoltaic modules, which comprises the following steps: conveying the photovoltaic modules into the pyrolysis furnace, and stopping at 450-550 DEG C for 20-40 min; then the photovoltaic modules enter the wet steam oxidation furnace, the water vapor temperature is 200-250 DEG C, and stopping for 20-40 min; and then the photovoltaic modules enter the cooling furnace for cooling and output. The system provided by the application can realize the separation of large and complete glass plates and high-quality silicon battery pieces.

Description

Technical Field

[0001] This invention relates to the field of harmless and resource-based disposal technology for retired photovoltaic modules, specifically to a recycling system and method for photovoltaic modules. Background Technology

[0002] With the rapid development of the photovoltaic industry and the continuous growth of global photovoltaic installed capacity, a large number of photovoltaic modules are approaching the end of their service life, and a wave of retirement is imminent. Retired photovoltaic modules contain materials with extremely high recycling value, such as glass, silicon solar cells, and metal wiring materials. Therefore, building an efficient, green, and resource-recyclable recycling technology system is an important issue for promoting sustainable development.

[0003] However, current mainstream recycling technologies still have several shortcomings. First, during the heat treatment process, uneven heating often leads to glass breakage, making it difficult to achieve non-destructive recycling of large-size glass. Second, traditional pyrolysis and chemical treatment methods are insufficient to completely remove residual carbon, organic impurities, and oxygen impurities from the surface of silicon solar cells, affecting their subsequent utilization performance. In addition, the oil and gas generated during pyrolysis cannot be fully recovered and reused, resulting in high external heating energy consumption, low overall energy efficiency, and environmental emission risks.

[0004] Therefore, there is an urgent need for a new type of recycling system that combines uniform heat treatment, clean resource extraction capabilities, and energy self-circulation characteristics. This system can ensure the integrity of large glass panels and the recycling of high-quality silicon solar cells while achieving the complete decomposition of organic impurities and full utilization of thermal energy, thereby improving the recycling efficiency and environmental protection level of retired photovoltaic modules. Summary of the Invention

[0005] Based on the problems existing in the background technology, and in order to solve the problems of large glass panels being difficult to recycle without damage, poor quality of recycled silicon cells, and low energy utilization efficiency in existing methods for recycling retired photovoltaic modules, this invention provides a photovoltaic module recycling system to achieve complete and damage-free recycling of high-quality, clean silicon cells and large glass panels. For example, it can use retired photovoltaic modules disassembled with aluminum frames and junction boxes as raw materials, and achieve uniform heating and decomposition of organic components such as EVA / backsheet through a coupled molten salt pyrolysis method, avoiding problems caused by uneven heating of retired photovoltaic modules. The internal stress imbalance of the components caused by the pyrolysis led to the breakage and damage of the glass panels. Further high-temperature wet steam oxidation was used to remove residual carbon from the retired photovoltaic modules, which had undergone pyrolysis to remove organic components such as EVA / backsheets. This cleaned the silicon cells and large glass panels. The CO and H2 generated during the wet steam oxidation process also provided a reducing atmosphere, further removing oxygen impurities from the glass panels and silicon cells, thus improving the quality of the silicon cells. The resulting large clean glass panels and silicon cells were then separated from the high-quality silicon cells by a rotating flexible brush combined with compressed air purging. In addition, the oil and gas generated from the pyrolysis of the raw materials of the retired photovoltaic modules were directly burned to provide heat for the removal and purification of residual carbon in the silicon cells and glass panels, as well as for maintaining the molten salt temperature, achieving energy self-sufficiency and eliminating the environmental hazards of tar.

[0006] To achieve the above-mentioned technical objectives, the present invention provides a photovoltaic module recycling system, comprising: a pyrolysis furnace, a wet steam oxidation furnace, and a cooling furnace;

[0007] The outlet of the pyrolysis furnace is connected to the inlet of the wet steam oxidation furnace, and the outlet of the wet steam oxidation furnace is connected to the inlet of the cooling furnace.

[0008] The pyrolysis furnace has molten salt heating tubes arranged circumferentially inside, which are used to provide heat; the wet steam oxidation furnace is used to introduce water vapor to oxidize the decommissioned photovoltaic modules after pyrolysis; the cooling furnace is used to cool the photovoltaic modules after water vapor treatment.

[0009] The pyrolysis furnace is provided with a pyrolysis oil and gas outlet, which is connected to the air inlet of the outer high-temperature flue gas heating pipe of the wet steam oxidation furnace.

[0010] In any embodiment, the pyrolysis furnace further includes a low-temperature molten salt storage tank and a high-temperature molten salt storage tank; the discharge end of the molten salt heating tube is connected to the feed end of the low-temperature molten salt storage tank, the discharge end of the low-temperature molten salt storage tank is connected to the feed end of the high-temperature molten salt storage tank, and the discharge end of the high-temperature molten salt storage tank is connected to the feed end of the molten salt heating tube.

[0011] In any embodiment, the wet steam oxidation furnace has a double-layered tube structure, including an inner tube and an outer high-temperature flue gas heating tube. The inner tube is disposed inside the outer high-temperature flue gas heating tube, and a burner is provided inside the outer high-temperature flue gas heating tube. The wet steam oxidation flue gas outlet of the inner tube is connected to the air inlet of the outer high-temperature flue gas heating tube, and the wet steam oxidation flue gas generated by the inner tube is transported to the outer high-temperature flue gas heating tube.

[0012] In any embodiment, an oxygen supply fan is also included, which is connected to the air inlet of the outer high-temperature flue gas heating pipe.

[0013] In any embodiment, it further includes a flue gas heat exchange-steam generator and a flue gas treatment device; the outlet of the outer high-temperature flue gas heating pipe is connected to the inlet of the flue gas heat exchange-steam generator, and the outlet of the flue gas heat exchange-steam generator is connected to the steam inlet of the inner sleeve and the inlet of the flue gas three-way valve respectively; the outlet of the flue gas three-way valve is connected to the inlet of the low-temperature molten salt storage tank and the inlet of the flue gas treatment device respectively.

[0014] In any embodiment, it also includes an induced draft fan and a chimney, the air inlet of the flue gas treatment equipment is connected to the flue gas three-way valve, the induced draft fan is connected to the air outlet of the flue gas treatment equipment and the chimney respectively, and the chimney is used to discharge exhaust gas.

[0015] In any embodiment, a buffer storage chamber is also included, the feed end of which is connected to the pyrolysis furnace, and the discharge end of which is connected to the wet steam oxidation furnace.

[0016] In any embodiment, a sample feeding device is also included, which is connected to the feed end of the pyrolysis furnace.

[0017] In any embodiment, the sample feeding device, the pyrolysis furnace, the buffer storage chamber, the wet steam oxidation furnace, and the cooling furnace are all equipped with conveyor chain rollers.

[0018] In any embodiment, the tail end of the cooling furnace is equipped with a rotating flexible brush and an air nozzle for separating the glass plate and the silicon solar cell.

[0019] This invention also proposes a method for recycling photovoltaic modules, which uses the aforementioned photovoltaic module recycling system for recycling and processing, including the following steps: conveying the photovoltaic modules to a pyrolysis furnace and holding them at 450~550°C for 20~40 minutes; then the photovoltaic modules enter a wet steam oxidation furnace, where the steam temperature is 200~250°C, and hold them for 20~40 minutes; then the photovoltaic modules enter a cooling furnace for cooling and are output.

[0020] Compared with the prior art, the beneficial effects of the present invention include: the present invention proposes a photovoltaic module recycling system, comprising: a pyrolysis furnace, a wet steam oxidation furnace, and a cooling furnace; the discharge port of the pyrolysis furnace is connected to the inlet of the wet steam oxidation furnace, and the discharge port of the wet steam oxidation furnace is connected to the inlet of the cooling furnace; molten salt heating tubes are arranged circumferentially inside the pyrolysis furnace, and the molten salt heating tubes are used to provide heat; the wet steam oxidation furnace is used to introduce steam to oxidize the pyrolyzed retired photovoltaic modules with wet steam; the cooling furnace is used to cool the photovoltaic modules after steam treatment; the pyrolysis furnace is provided with a pyrolysis oil and gas outlet, and the pyrolysis oil and gas outlet is connected to the inlet of the outer high-temperature flue gas heating tube of the wet steam oxidation furnace. This invention achieves uniform heating and decomposition of organic components such as EVA / backsheet in decommissioned photovoltaic modules with disassembled aluminum frames and junction boxes through molten salt pyrolysis using coupled molten salt heating pipes. This avoids internal stress imbalance caused by uneven heating, which can lead to glass breakage and damage. Furthermore, high-temperature wet steam oxidation removes residual carbon from the decommissioned photovoltaic modules after pyrolysis to remove EVA / backsheet and other organic components. The CO and H2 generated during the wet steam oxidation process also provide a reducing atmosphere, further removing oxygen impurities from the glass and silicon cells and improving the quality of the silicon cells. This allows for the separation of large, intact glass panels and high-quality silicon cells. In addition, the oil and gas generated from the pyrolysis of the raw materials of the decommissioned photovoltaic modules are directly burned in the wet steam oxidation furnace to provide heat for the removal and purification of residual carbon in the silicon cells and glass panels, achieving energy self-sufficiency and eliminating the environmental hazards of tar. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the structure of a photovoltaic module recycling system proposed in Embodiment 1 of the present invention.

[0022] Figure 2 yes Figure 1 Sectional view of AA.

[0023] Explanation of reference numerals in the attached drawings: 1. Sample inlet; 2. Sample inlet device; 3. Sample inlet conveyor roller; 4. Movable heat insulation plate for sample inlet of pyrolysis furnace; 5. Molten salt heating tube; 6. Pyrolysis furnace; 7. Pyrolysis conveyor roller; 8. Movable heat insulation plate for sample outlet of pyrolysis furnace; 9. Pyrolysis oil and gas outlet; 10. Buffer storage chamber; 11. Oxygen supply fan; 12. Buffer storage conveyor roller; 13. Movable heat insulation plate for sample inlet of wet steam oxidation furnace; 14. Burner; 15. Wet steam oxidation conveyor roller; 16. High-temperature flue gas heating tube; 17. Wet steam oxidation furnace; 18. Movable heat insulation plate for sample inlet of cooling device; 19. Wet steam oxidation flue gas outlet; 20 Cooling furnace; 21 Cooling water outlet; 22 Rotating flexible brush; 23 Compressed air nozzle; 24 Large complete glass plate outlet; 25 High-quality silicon solar cell recycling outlet; 26 Cooling conveyor chain roller; 27 Cooling water inlet; 28 High-temperature flue gas outlet; 29 Feed water pump; 30 Chimney; 31 Exhaust fan; 32 Flue gas heat exchange-steam generator; 33 Flue gas treatment equipment; 34 Flue gas three-way valve; 35 Steam inlet; 36 Low-temperature molten salt storage tank; 37 Low-temperature molten salt pump; 38 High-temperature molten salt storage tank; 39 High-temperature molten salt pump; 40 Roller. Detailed Implementation

[0024] The "range" disclosed in this application is defined by a lower limit and an upper limit. A given range is defined by selecting a lower limit and an upper limit, which define the boundaries of a particular range. Ranges defined in this way can include or exclude endpoints and can be arbitrarily combined; that is, any lower limit can be combined with any upper limit to form a range. For example, if ranges of 60~120 and 80~110 are listed for a specific parameter, it is also expected that ranges of 60~110 and 80~120 are also included. Furthermore, if minimum range values ​​of 1 and 2 are listed, and if maximum range values ​​of 3, 4, and 5 are listed, then the following ranges are all expected: 1~3, 1~4, 1~5, 2~3, 2~4, and 2~5. In this application, unless otherwise stated, the numerical range "a~b" represents a shortened representation of any combination of real numbers between a and b, where a and b are real numbers. For example, the numerical range "0~5" indicates that all real numbers between "0~5" have been listed in this article; "0~5" is simply a shortened representation of these numerical combinations. Furthermore, when a parameter is stated as an integer ≥2, it is equivalent to disclosing that the parameter is, for example, an integer such as 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.

[0025] Unless otherwise specified, the terms "comprising" and "including" as used in this application can be open-ended or closed-ended. For example, "comprising" and "including" can mean that other components not listed may also be included, or that only the listed components may be included.

[0026] Unless otherwise specified, the term "or" is inclusive in this application. For example, the phrase "A or B" means "A, B, or both A and B". More specifically, the condition "A or B" is satisfied by any of the following conditions: A is true (or exists) and B is false (or does not exist); A is false (or does not exist) and B is true (or exists); or both A and B are true (or exist).

[0027] It should be explained that, in the following embodiments, the movable heat insulation plate refers to the heat insulation plate that can be opened to allow materials to pass through. Example 1

[0028] Combination Figure 1-2 This embodiment provides a photovoltaic module recycling system, including: a pyrolysis furnace 6, a wet steam oxidation furnace 17, and a cooling furnace 20;

[0029] The discharge port of the pyrolysis furnace 6 is connected to the inlet of the wet steam oxidizer 17, and the discharge port of the wet steam oxidizer 17 is connected to the inlet of the cooling furnace 20.

[0030] The pyrolysis furnace 6 has several molten salt heating tubes 5 arranged circumferentially inside, which are used to provide heat; the wet steam oxidation furnace 17 is used to introduce water vapor to oxidize the pyrolyzed retired photovoltaic modules with wet steam; the cooling furnace 20 is used to cool the photovoltaic modules after water vapor treatment.

[0031] The pyrolysis furnace 6 is equipped with a pyrolysis oil and gas outlet 9, which is connected to the air inlet of the outer high-temperature flue gas heating pipe 16 of the wet steam oxidation furnace 17.

[0032] Molten salt heating tube 5 is used to achieve uniform heating and thermal decomposition of organic components such as EVA / backsheet in pyrolysis furnace 6 for retired photovoltaic modules, reducing or eliminating internal stress imbalance caused by uneven heating of retired photovoltaic modules and resulting in glass breakage and damage. Pyrolysis oil and gas outlet 9 is opened in the upper rear area of ​​pyrolysis furnace 6. The tail of pyrolysis furnace 6 is connected to buffer storage chamber 10 by installing movable heat insulation plate 8 at pyrolysis furnace outlet.

[0033] In this embodiment, the cooling furnace 20 is equipped with a cooling conveyor chain roller 26 for transporting retired photovoltaic modules during the cooling process after pyrolysis and wet steam oxidation upgrading. A cooling water inlet 27 and a cooling water outlet 21 are respectively arranged at the lower front end and upper rear end of the cooling furnace 20. A rotating flexible brush 22 is installed at the tail end of the cooling furnace 20. After a series of treatments including pyrolysis, wet steam oxidation upgrading, and cooling, the retired photovoltaic modules are separated from large intact glass panels and high-quality silicon solar cells by the rotating flexible brush 22 combined with compressed air injected through the compressed air nozzle 23. The separated and recovered large intact glass panels are collected at the large intact glass panel outlet 24, while the recovered high-quality clean silicon solar cells are collected at the high-quality silicon solar cell recovery outlet 25.

[0034] Based on the above embodiments, the pyrolysis furnace 6 in this embodiment also includes a low-temperature molten salt storage tank 36 and a high-temperature molten salt storage tank 38; the discharge end of the molten salt heating tube 5 is connected to the feed end of the low-temperature molten salt storage tank 36, the discharge end of the low-temperature molten salt storage tank 36 is connected to the feed end of the high-temperature molten salt storage tank 38, and the discharge end of the high-temperature molten salt storage tank 38 is connected to the feed end of the molten salt heating tube 5.

[0035] Based on the above embodiments, the wet steam oxidizer 17 in this embodiment has a double-layer sleeve structure, including an inner sleeve and an outer high-temperature flue gas heating tube 16. The inner sleeve is located inside the outer high-temperature flue gas heating tube 16, and a burner 14 is provided inside the outer high-temperature flue gas heating tube 16. The wet steam oxidation flue gas outlet 19 of the inner sleeve is connected to the air inlet of the outer high-temperature flue gas heating tube 16, and the wet steam oxidation flue gas generated by the inner sleeve is transported to the outer high-temperature flue gas heating tube 16.

[0036] Based on the above embodiments, this embodiment also includes an oxygen supply fan 11, which is connected to the air inlet of the outer high-temperature flue gas heating pipe 16.

[0037] The wet steam oxidation furnace 17 removes residual carbon from decommissioned photovoltaic modules that have undergone thermal desorption to remove organic components such as EVA / backsheet through high-temperature wet steam oxidation, thus purifying the silicon cells and large glass panels. Furthermore, the CO and H2 generated during the wet steam oxidation process provide a reducing atmosphere for the decommissioned photovoltaic modules, further removing oxygen impurities present in the glass panels and silicon cells, thereby improving the quality of the silicon cells. The wet steam oxidation furnace 17 has a water steam inlet 35 at the front end of its inner sleeve, and a steam supply port at the rear end. The flue gas generated by steam oxidation is discharged through the wet steam oxidation flue gas outlet 19; the bottom of the rear end of the outer high-temperature flue gas heating pipe 16 of the wet steam oxidation furnace 17 has a high-temperature flue gas outlet 28 for discharging high-temperature flue gas, and is equipped with a burner 14, so as to realize the mixing, ignition and combustion of the combustion air supplied by the oxygen supply unit 11, the pyrolysis oil gas discharged from the pyrolysis oil gas outlet 9 and the wet steam oxidation flue gas discharged from the wet steam oxidation flue gas outlet 19 in the outer high-temperature flue gas heating pipe 16, to generate high-temperature flue gas and provide heat for the wet steam oxidation furnace 17.

[0038] Based on the above embodiments, this embodiment further includes a flue gas heat exchange-steam generator 32 and a flue gas treatment device 33; the high-temperature flue gas outlet 28 of the outer high-temperature flue gas heating pipe 16 is connected to the air inlet of the flue gas heat exchange-steam generator 32, and the air outlet of the flue gas heat exchange-steam generator 32 is connected to the steam inlet 35 of the inner sleeve of the wet steam oxidizer 17 and the air inlet of the flue gas three-way valve 34, respectively; the air outlet of the flue gas three-way valve 34 is connected to the low-temperature molten salt storage tank 36 and the air inlet of the flue gas treatment device 33, respectively. The flue gas heat exchange-steam generator 32 is connected to the high-temperature flue gas outlet 28 and the flue gas three-way valve 34, respectively; deionized water is fed through a water pump 29 to control the water supply, and is heated and heated by the non-contact heat exchange of the flue gas heat exchange-steam generator 32 to generate steam, and the generated steam is sent into the inner sleeve of the wet steam oxidizer 17 through the steam inlet 35. The low-temperature molten salt storage tank 36 is connected to the outlet of the molten salt heating pipe 5. The low-temperature molten salt, after heat exchange in the pyrolysis furnace 6, flows back to the low-temperature molten salt storage tank 36 and is heated and heated through non-contact heat exchange with the high-temperature flue gas to recover the waste heat of the flue gas. The temperature of the molten salt in the low-temperature molten salt storage tank 36 is controlled by controlling the opening of the flue gas three-way valve 34 to make the flow rate of the high-temperature flue gas entering the low-temperature molten salt storage tank 36 controllable. The remaining high-temperature flue gas directly enters the flue gas treatment equipment 33. The molten salt that has reached the target temperature after heat exchange with the high-temperature hot flue gas is further transported to the high-temperature molten salt storage tank 38 through the low-temperature molten salt pump 37.

[0039] Based on the above embodiments, in this embodiment, the high-temperature molten salt storage tank 38 delivers molten salt to the molten salt heating pipe 5 through the high-temperature molten salt pump 39, providing heat for the pyrolysis of retired photovoltaic modules and the separation of organic components such as EVA / backsheet.

[0040] Based on the above embodiments, this embodiment also includes an induced draft fan 31 and a chimney 30. The air inlet of the flue gas treatment device 33 is connected to the flue gas three-way valve 34. The induced draft fan 31 is connected to the air outlet of the flue gas treatment device 33 and the chimney 30 respectively. The chimney 30 is used to discharge exhaust gas.

[0041] Based on the above embodiments, in this embodiment, the sample feeding device 2, pyrolysis furnace 6, buffer storage chamber 10, wet steam oxidation furnace 17 and cooling furnace 20 are all equipped with conveyor chain rollers.

[0042] In this embodiment, a pyrolysis conveyor chain roller 7 is installed in the pyrolysis furnace 6 to transport the retired photovoltaic modules in the pyrolysis furnace 6; several molten salt heating tubes 5 are evenly arranged circumferentially in the pyrolysis furnace 6 to ensure that the retired photovoltaic modules are uniformly heated and heated in the pyrolysis furnace 6, and the organic components such as EVA / backsheet are thermally decomposed, thereby reducing or eliminating the internal stress imbalance of the retired photovoltaic modules caused by uneven heating and resulting in the breakage and damage of the glass plate; a pyrolysis oil and gas outlet 9 is opened in the upper rear area of ​​the pyrolysis furnace 6; the tail of the pyrolysis furnace 6 is connected to the buffer storage chamber 10 by installing a movable heat insulation plate at the outlet of the pyrolysis furnace 6.

[0043] Based on the above embodiments, this embodiment further includes a buffer storage chamber 10. The feed end of the buffer storage chamber 10 is connected to the pyrolysis furnace 6, and the discharge end of the buffer storage chamber 10 is connected to the wet steam oxidation furnace 17. A buffer storage conveyor roller 12 is installed in the buffer storage chamber 10 to transport the decommissioned photovoltaic modules after the organic components such as EVA / backsheet have been removed by pyrolysis. The tail of the buffer storage chamber 10 is connected to the wet steam oxidation furnace 17 via a movable heat insulation plate 13 for feeding the wet steam oxidation furnace. The wet steam oxidation furnace 17 is equipped with a wet steam oxidation conveyor roller 15 for transporting decommissioned photovoltaic modules. The tail of the wet steam oxidation furnace 17 is connected to the cooling furnace 20 via a movable heat insulation plate 18 for feeding the cooling device.

[0044] Based on the above embodiments, this embodiment also includes a sampling device 2, which is connected to the feed end of the pyrolysis furnace 6. The sampling device 2 has a sampling port 1 at its front end and a sampling conveyor chain roller 3 arranged within it for feeding and transporting retired photovoltaic modules to be recycled. The sampling device 2 and the pyrolysis furnace 6 are connected via a movable heat insulation plate 4 for sampling in the pyrolysis furnace, reducing the entry of outside air and maintaining an inert atmosphere in the pyrolysis furnace 6. The retired photovoltaic modules can enter the pyrolysis furnace 6 through the movable heat insulation plate 4 for sampling in the pyrolysis furnace.

[0045] This embodiment also proposes a method for recycling photovoltaic modules, which uses the above-mentioned photovoltaic module recycling system for recycling and processing, including the following steps: the photovoltaic modules are transported to a pyrolysis furnace and held at 450~550°C for 20~40 minutes; then the photovoltaic modules are put into a wet steam oxidation furnace, where the steam temperature is 200~250°C and held for 20~40 minutes; then the photovoltaic modules are cooled in a cooling furnace and output.

[0046] Specifically, in combination Figure 1 The photovoltaic module recycling system proposed in this embodiment processes the photovoltaic modules to be recycled as follows:

[0047] First, the decommissioned photovoltaic module S1 with its aluminum frame and junction box removed is placed with the glass side facing down. It is then fed into the sampling device 2 through the sampling port 1 and onto the upper side of the sampling conveyor chain roller 3. The module is then transported by the conveyor chain roller 3 and enters the pyrolysis furnace 6 through the pyrolysis furnace sampling movable heat insulation plate 4.

[0048] The pyrolysis furnace 6 provides heat and maintains the temperature at 450~550°C through molten salt heating tubes 5 arranged uniformly along the circumference. Organic components such as EVA and backsheet in the photovoltaic module undergo thermal decomposition in the pyrolysis furnace 6 with a uniform temperature field distribution, eliminating the breakage and damage of photovoltaic glass caused by stress imbalance due to uneven heating. The pyrolysis photovoltaic module is composed of large-sized glass plates, silicon solar cells, and a small amount of residual carbon. The retired photovoltaic module S2 being pyrolyzed moves slowly through the pyrolysis conveyor roller 7, with a residence time of 20~40 minutes. The pyrolysis oil and gas generated by pyrolysis is discharged from the pyrolysis oil and gas outlet 9.

[0049] After complete pyrolysis, the decommissioned photovoltaic modules are sent to the buffer storage chamber 10 through the movable heat insulation plate 8 at the outlet of the pyrolysis furnace 6, and then sent to the wet steam oxidation furnace 17 through the buffer storage conveyor chain roller 12 and the wet steam oxidation furnace feed movable heat insulation plate 13.

[0050] The decommissioned photovoltaic module S4 undergoing wet steam oxidation moves slowly within the inner sleeve of the wet steam oxidation furnace 17 via the wet steam oxidation conveyor roller 15, with a residence time of 20-40 minutes. The inner sleeve introduces water vapor to oxidize the decommissioned photovoltaic module after complete pyrolysis in a high-temperature environment, removing residual carbon from the decommissioned photovoltaic module. The CO and H2 generated during the wet steam oxidation process also provide a reducing atmosphere, further removing some oxygen-containing impurities from the glass sheets and silicon cells, thereby improving the quality of the silicon cells and purifying the large glass panels. The water vapor introduced into the inner sleeve is at a temperature of 200-250°C. The wet steam oxidation flue gas is discharged from the wet steam oxidation flue gas outlet 19.

[0051] The high-temperature environment of the inner sleeve of the wet steam oxidizer 17 is maintained by the combustion of pyrolysis oil and gas, wet steam oxidation flue gas and combustion air supplied by oxygen supply fan 11 in the burner 14 arranged in the outer sleeve 16 of the wet steam oxidizer 17 to generate high-temperature flue gas. The temperature of the high-temperature flue gas generated by combustion is 900~1000°C.

[0052] Decommissioned photovoltaic modules that have completed wet steam oxidation are fed into the cooling furnace 20 via wet steam oxidation conveyor roller 15 and a cooling device sample inlet movable heat insulation plate 18, and are cooled by circulating cooling water; the decommissioned photovoltaic modules S5 that are being cooled are conveyed by cooling conveyor roller 26; a rotating flexible brush 22 is installed at the tail of the cooling furnace 20, and the large intact glass plate and high-quality silicon solar cells are separated by the rotating flexible brush 22 combined with the compressed air injected by the compressed air nozzle 23; the large intact glass plate recovered after separation is collected by the large intact glass plate outlet 24, while the high-quality clean silicon solar cells are collected by the high-quality silicon solar cell recovery outlet 25.

[0053] The high-temperature flue gas discharged from the high-temperature flue gas outlet 28 enters the flue gas heat exchange-steam generator 32, where it provides heat for heating deionized water to generate steam through non-contact heat exchange. After heat exchange, the high-temperature flue gas is diverted through the flue gas three-way valve 34. Part of it enters the low-temperature molten salt storage tank 36 to provide heat for heating the low-temperature molten salt to 450~550°C, while the remaining part enters the flue gas treatment equipment 33.

[0054] After the molten salt in the low-temperature molten salt storage tank 36 is heated to the target temperature (450~550°C), it is sent to the high-temperature molten salt storage tank 38 through the low-temperature molten salt pump 37. The molten salt in the high-temperature molten salt storage tank 38 is sent to the molten salt heating pipes 5 that are uniformly arranged circumferentially in the pyrolysis furnace 6 through the high-temperature molten salt pump 39, so as to provide heat for the thermal decomposition of organic components such as EVA and backsheet in the retired photovoltaic modules.

[0055] Combination Figure 2 It can be seen that the molten salt heating tube 5 is arranged along the internal circumference of the pyrolysis furnace, and the roller 40 of the pyrolysis conveyor chain roller 7 is located inside the pyrolysis furnace 6.

[0056] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0057] In this invention, the terms "some embodiments," "this embodiment," and examples are used to describe a subset of all possible embodiments. However, it is understood that "some embodiments" can be the same subset or different subsets of all possible embodiments and can be combined with each other without conflict.

[0058] If the application documents contain similar descriptions such as "first / second", the following explanation shall be added: In the following description, the terms "first / second / third" are used only to distinguish similar objects and do not represent a specific ordering of objects. It is understood that "first / second / third" may be interchanged in a specific order or sequence where permitted, so that the embodiments described herein can be implemented in an order other than that illustrated or described herein.

[0059] In this embodiment, the term "and / or" is merely a description of the relationship between related objects, indicating that there can be three relationships. For example, object A and / or object B can represent three situations: object A exists alone, object A and object B exist simultaneously, and object B exists alone.

[0060] The following describes embodiments of this application. The embodiments described below are exemplary and are only used to explain this application, and should not be construed as limiting this application. Where specific techniques or conditions are not specified in the embodiments, they are performed according to the techniques or conditions described in the literature in this field or according to the product instructions. Reagents or instruments used, unless otherwise specified, are all conventional products that can be obtained commercially.

[0061] The specific embodiments of the present invention described above do not constitute a limitation on the scope of protection of the present invention. Any other corresponding changes and modifications made in accordance with the technical concept of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A photovoltaic module recycling system, characterized in that, include: Pyrolysis furnace, wet steam oxidation furnace, and cooling furnace; The outlet of the pyrolysis furnace is connected to the inlet of the wet steam oxidation furnace, and the outlet of the wet steam oxidation furnace is connected to the inlet of the cooling furnace. The pyrolysis furnace has molten salt heating tubes arranged circumferentially inside, which are used to provide heat; the wet steam oxidation furnace is used to introduce water vapor to oxidize the decommissioned photovoltaic modules after pyrolysis; the cooling furnace is used to cool the photovoltaic modules after water vapor treatment. The pyrolysis furnace is provided with a pyrolysis oil and gas outlet, which is connected to the air inlet of the outer high-temperature flue gas heating pipe of the wet steam oxidation furnace.

2. The photovoltaic module recycling system according to claim 1, characterized in that, The pyrolysis furnace also includes a low-temperature molten salt storage tank and a high-temperature molten salt storage tank; the discharge end of the molten salt heating tube is connected to the feed end of the low-temperature molten salt storage tank, the discharge end of the low-temperature molten salt storage tank is connected to the feed end of the high-temperature molten salt storage tank, and the discharge end of the high-temperature molten salt storage tank is connected to the feed end of the molten salt heating tube.

3. The photovoltaic module recycling system according to claim 1, characterized in that, The wet steam oxidation furnace has a double-layered tube structure, including an inner tube and an outer high-temperature flue gas heating tube. The inner tube is located inside the outer high-temperature flue gas heating tube, and a burner is installed inside the outer high-temperature flue gas heating tube. The wet steam oxidation flue gas outlet of the inner tube is connected to the air inlet of the outer high-temperature flue gas heating tube, and the wet steam oxidation flue gas generated by the inner tube is transported to the outer high-temperature flue gas heating tube.

4. The photovoltaic module recycling system according to claim 3, characterized in that, It also includes an oxygen supply fan, which is connected to the air inlet of the outer high-temperature flue gas heating pipe.

5. The photovoltaic module recycling system according to claim 3, characterized in that, It also includes a flue gas heat exchange-steam generator and a flue gas treatment device; the outlet of the outer high-temperature flue gas heating pipe is connected to the inlet of the flue gas heat exchange-steam generator, and the outlet of the flue gas heat exchange-steam generator is connected to the steam inlet of the inner sleeve and the inlet of the flue gas three-way valve respectively; the outlet of the flue gas three-way valve is connected to the inlet of the low-temperature molten salt storage tank and the inlet of the flue gas treatment device respectively.

6. The photovoltaic module recycling system according to claim 5, characterized in that, It also includes an induced draft fan and a chimney. The air inlet of the flue gas treatment equipment is connected to the flue gas three-way valve. The induced draft fan is connected to the air outlet of the flue gas treatment equipment and the chimney. The chimney is used to discharge exhaust gas.

7. The photovoltaic module recycling system according to claim 1, characterized in that, It also includes a buffer storage chamber, the feed end of which is connected to the pyrolysis furnace, and the discharge end of which is connected to the wet steam oxidation furnace.

8. The photovoltaic module recycling system according to claim 7, characterized in that, It also includes a sample feeding device, which is connected to the feed end of the pyrolysis furnace.

9. The photovoltaic module recycling system according to claim 8, characterized in that, The sample feeding device, the pyrolysis furnace, the buffer storage chamber, the wet steam oxidation furnace, and the cooling furnace are all equipped with conveyor chain rollers; and / or, the tail end of the cooling furnace is equipped with a rotating flexible brush and an air nozzle for separating the glass plate and the silicon solar cell.

10. A method for recycling photovoltaic modules, characterized in that, The photovoltaic module recycling system according to any one of claims 1-9 is used for recycling, including the following steps: transporting the photovoltaic module to a pyrolysis furnace and holding it at 450~550°C for 20~40 minutes; The photovoltaic modules then enter a wet steam oxidation furnace, where the steam temperature is 200~250°C, and remain for 20~40 minutes; afterwards, the photovoltaic modules enter a cooling furnace for cooling and are then output.

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