Method for efficiently dissociating retired double-glass crystalline silicon photovoltaic module by using thermal method

Abstract

The invention discloses a method for efficiently dissociating a retired double-glass crystalline silicon photovoltaic module by a thermal method, which comprises the following steps of: (1) mechanically disassembling the retired double-glass crystalline silicon photovoltaic module to obtain an aluminum frame, a junction box and a double-glass crystalline silicon photovoltaic laminated piece; (2) carrying out preliminary judgment on the laminated piece to obtain a complete laminated piece and a broken laminated piece; (3) the laminated part is subjected to pyrolysis treatment, and pyrolysis oil, pyrolysis gas and a pyrolysis solid mixture are obtained; (4) feeding the pyrolytic oil and the pyrolytic gas to a combustion chamber for combustion, and supplying heat to the pyrolytic reaction container; and (5) cooling the pyrolysis solid mixture to obtain glass, a silicon wafer and a tin-plated solder strip. The method provided by the invention is compatible with double-glass laminates in different physical states, and the packaging medium removal rate gt; the treatment efficiency is high. Pyrolysis oil and pyrolysis gas are high in heat value, energy consumption is effectively reduced through heat energy recycling through combustion, tail gas is mainly carbon dioxide, the follow-up purification pressure is small, and the method is suitable for large-scale recycling of the double-glass photovoltaic laminated parts.

Description

Technical Field

[0001] This invention relates to the field of photovoltaic module recycling technology, specifically to a method for efficient thermal dissociation of retired double-glass crystalline silicon photovoltaic modules. Background Technology

[0002] With the rapid development of the renewable energy industry, solar photovoltaic (PV) has been widely adopted due to its advantages such as flexible expansion and convenient deployment. In 2024, the global newly installed PV capacity was approximately 550 GW, and the cumulative installed capacity has exceeded 2 TW, with crystalline silicon PV modules accounting for about 95%. Over the next 25-30 years, the scale of retired PV modules globally will continue to grow, and it is estimated that by 2050, the cumulative amount of retired modules will reach 60-78 million tons. If not properly disposed of, heavy metals such as lead and copper contained in the waste modules can easily leak, posing potential risks to the ecological environment and human health. At the same time, PV modules contain high-purity valuable materials such as silicon, aluminum, silver, and copper, making their resource utilization value significant. Therefore, achieving efficient recycling and reuse of retired PV modules is of great significance for reducing environmental pressure and ensuring the sustainable supply of key materials.

[0003] Crystalline silicon photovoltaic modules mainly consist of an aluminum frame, a junction box, encapsulation media (EVA film, POE film, and their co-extruded films), solar cells, and a backsheet. The mechanical removal processes for the aluminum frame and junction box are relatively mature. The laminated structure obtained after removing the frame and junction box is the laminate, which, as the core structure of the photovoltaic module, accounts for approximately 70% of the module's total value. Achieving efficient dissociation of the laminate is a crucial prerequisite for the efficient recovery of valuable components from crystalline silicon photovoltaic modules.

[0004] Double-glass modules, as a new type of photovoltaic module structure, use double-layer tempered glass to replace the traditional fluorinated backsheet, significantly improving the module's structural strength, durability, lifespan, and power generation efficiency. With continuous technological iteration, the market share of double-glass photovoltaic modules is constantly increasing, projected to grow from 50% in 2024 to 70% in 2035. However, the fully enclosed structure resulting from double-layer glass also significantly increases the difficulty of delaminating the laminates.

[0005] Currently, laminate recycling technologies mainly include physical, chemical, and thermal methods. Physical methods achieve separation through crushing and sorting, which are simple processes, but the purity of the recovered products is low, and organic residues remain. Chemical methods use solvents to cause the encapsulation medium to swell and peel off, with mild conditions and minimal damage to the solar cells, but suffer from low processing efficiency and difficulties in solvent recovery and wastewater treatment. Pyrolysis can quickly and efficiently remove the encapsulation film, showing significant advantages in large-scale industrial applications. Domestic research has been conducted on the pyrolysis recycling of laminates, with the following representative technologies: Patent CN114951209A discloses a method of preheating the separated glass before thermally removing the encapsulation film; Patents CN119819686A and CN120662612A respectively disclose methods of using a hot knife to cut and separate the glass and remove the encapsulation film. All of these methods rely on intact glass, making them less suitable for retired modules with broken glass. Patent CN117778720A employs microwave heating to melt the adhesive film, followed by rapid cooling and cracking to remove brittleness, and then uses water washing and vibration to remove residual adhesive film. Patent CN120532840A uses gradient heating to achieve glass separation and adhesive film pyrolysis. These methods require repeated heating and cooling, have long processing cycles, and high energy consumption, making them unsuitable for continuous production. Patent CN114410320A discloses a method and system for synergistic full-component recovery through photovoltaic module pyrolysis, removing fluorides through spray absorbent, but the pyrolysis oil and gas are not effectively utilized, and it is not applicable to the recycling of double-glass modules. There is an urgent need to develop a new, efficient thermal dissociation method suitable for retired double-glass crystalline silicon photovoltaic modules to overcome the current technological bottlenecks. Summary of the Invention

[0006] This invention addresses the problems of existing technologies by providing a highly efficient thermal decomposition method for retired double-glass crystalline silicon photovoltaic modules. This method is compatible with double-glass laminates of different physical states and sizes, requires no pretreatment, and can completely remove the encapsulation medium from the double-glass crystalline silicon photovoltaic laminates without generating residual carbon, while maintaining high processing efficiency. By adjusting the operating parameters of the pyrolysis treatment, over 99% of the encapsulation medium is converted into high-calorific-value pyrolysis oil and pyrolysis gas, which can be directly burned for heat energy recovery to reduce energy consumption. The exhaust gas is mainly carbon dioxide, requiring low subsequent purification pressure, making it suitable for large-scale recycling of double-glass photovoltaic laminates.

[0007] This invention protects a method for efficient thermal decomposition of decommissioned double-glass crystalline silicon photovoltaic modules, comprising the following steps:

[0008] (1) The retired double-glass crystalline silicon photovoltaic module is mechanically disassembled to separate the aluminum frame, junction box and double-glass crystalline silicon photovoltaic laminate, wherein the double-glass crystalline silicon photovoltaic laminate includes a front glass plate, a first encapsulation medium, a silicon wafer, a second encapsulation medium and a rear glass plate connected in sequence.

[0009] (2) The double-glass crystalline silicon photovoltaic laminate obtained in step (1) is preliminarily judged and classified into complete laminates and broken laminates;

[0010] (3) The complete or broken laminate obtained in step (2) is sent into a pyrolysis reaction vessel for pyrolysis treatment. The pyrolysis reaction vessel is a roller-driven forward pyrolysis furnace to obtain pyrolysis oil, pyrolysis gas and pyrolysis solid mixture.

[0011] (4) The pyrolysis oil and pyrolysis gas obtained in step (3) are transported to the combustion chamber for combustion to provide heat for the pyrolysis reaction vessel. After combustion, a gas mixture mainly composed of carbon dioxide is obtained.

[0012] (5) The pyrolysis solid mixture obtained in step (3) is sent to a cooling reaction vessel for cooling treatment, and then sorted and sorted to obtain glass, silicon wafers and tin-coated solder ribbons.

[0013] The method proposed in this invention obtains the thermal dissociation products of retired double-glass crystalline silicon photovoltaic laminates with a packaging medium removal rate of >99%. The complete laminates can achieve whole-pane glass recycling. The pyrolysis oil and pyrolysis gas have high calorific value and can be reused for heat energy through combustion, effectively reducing energy consumption.

[0014] Preferably, the first or second encapsulation medium in step (2) is selected from EVA, POE and EVA / POE / EVA co-extruded composite film.

[0015] Further preferred, the pyrolysis treatment conditions in step (3) are: pyrolysis temperature of 300℃-800℃, pyrolysis time of 10-120 min, heating method of electric heating or natural gas heating, pyrolysis atmosphere of nitrogen atmosphere, and the first and second packaging media are decomposed into pyrolysis oil and pyrolysis gas through pyrolysis treatment.

[0016] Further preferred, the pyrolysis conditions in step (3) are: pyrolysis temperature of 500℃-600℃ and pyrolysis time of 20-30 min.

[0017] Further preferred, the pyrolysis conditions in step (3) are: pyrolysis temperature of 550℃-600℃ and pyrolysis time of 20-30 min.

[0018] Preferably, the roller spacing of the roller-driven forward pyrolysis furnace described in step (3) is 50-150 mm, the width of the heating area of ​​the pyrolysis furnace is 1500-2500 mm, the length is 10-80 m, and the roller surface linear speed is 100-2000 mm / min.

[0019] Preferably, the calorific value of the pyrolysis oil in step (4) is in the range of 30-60 MJ / kg, and the calorific value of the pyrolysis gas is in the range of 30-60 MJ / m³. 3 .

[0020] Further preferred, the calorific value of the pyrolysis oil in step (4) is in the range of 40-45 MJ / kg, and the calorific value of the pyrolysis gas is in the range of 40-45 MJ / m³. 3 .

[0021] Preferably, the cooling reaction vessel in step (5) is a roller-driven forward cooling furnace with the same structure as in step (3), with a cooling area width of 1500-2500 mm, a length of 10-80 m, a roller surface linear speed of 100-2000 mm / min, a cooling time of 10-120 min, and a cooling method of water cooling.

[0022] Preferably, the cooling temperature in step (5) is 15℃-25℃.

[0023] This invention protects the application of the above method in the separation and recycling of decommissioned double-glass crystalline silicon photovoltaic modules.

[0024] Compared with existing technologies, this invention has the following advantages: The proposed efficient thermal decomposition method for retired double-glass crystalline silicon photovoltaic modules is applicable to double-glass photovoltaic laminates in various physical states. The laminates require no pretreatment and can be directly pyrolyzed. The encapsulating medium is completely removed, allowing for the recycling of the entire glass panel. The pyrolysis reaction vessel does not require frequent heating and cooling, enabling continuous and efficient decomposition of the laminates and significantly improving processing efficiency. The pyrolysis oil and gas generated from the pyrolysis of the encapsulating medium have high calorific value and are burned in the combustion chamber to heat the pyrolysis furnace, effectively reducing energy consumption. The main component of the exhaust gas is carbon dioxide, resulting in low subsequent purification pressure. Attached Figure Description

[0025] Figure 1 This is a schematic flowchart of the efficient thermal dissociation method for decommissioned double-glass crystalline silicon photovoltaic modules proposed in this invention.

[0026] Figure 2 The yields of the three-phase products from the pyrolysis of double-glass crystalline silicon photovoltaic laminates under different pyrolysis treatment conditions in Examples 1-4 are shown. Detailed Implementation

[0027] The following embodiments are further illustrations of the present invention, but not limitations thereof.

[0028] Unless otherwise defined, all technical terms used herein have the same meaning as commonly understood by those skilled in the art. The technical terms used herein are for the purpose of describing particular embodiments only and are not intended to limit the scope of the invention. Unless otherwise specified, the experimental materials and reagents used herein are commercially available products conventional in this technical field. The photovoltaic module processed in this invention is a biglass crystalline silicon photovoltaic module.

[0029] In the following embodiments, the double-glass crystalline silicon photovoltaic laminate includes a front glass plate, a first encapsulation medium, a silicon wafer, a second encapsulation medium, and a rear glass plate connected in sequence. The first encapsulation medium or the second encapsulation medium is selected from EVA, POE, and EVA / POE / EVA co-extruded composite film.

[0030] Example 1:

[0031] like Figure 1 As shown, a method for efficient thermal decomposition of decommissioned double-glass crystalline silicon photovoltaic modules includes the following steps:

[0032] (1) The retired double-glass crystalline silicon photovoltaic module was disassembled and the aluminum frame, junction box and double-glass crystalline silicon photovoltaic laminate were separated.

[0033] (2) The retired double-glass crystalline silicon photovoltaic laminates were initially judged and classified into complete laminates and broken laminates. The laminates were 2400 mm long and 1400 mm wide.

[0034] (3) The laminate obtained in step (2) is fed into a roller-driven forward pyrolysis furnace through the feed port for pyrolysis treatment. The pyrolysis zone of the pyrolysis furnace is 9.0 m long, the roller spacing is 100 mm, the roller width is 1500 mm, the roller surface linear speed is 300 mm / min, the pyrolysis atmosphere is nitrogen atmosphere, the pyrolysis temperature is controlled at 600 ± 5℃, and the pyrolysis time is 30 min. Pyrolysis oil, pyrolysis gas and pyrolysis solid mixture are obtained. The first and second packaging media are decomposed into pyrolysis oil and pyrolysis gas after pyrolysis treatment. The pyrolysis solid mixture includes the front glass plate, silicon wafer and rear glass plate.

[0035] (4) The pyrolysis oil and pyrolysis gas obtained in step (3) are transported to the combustion chamber for combustion to provide heat for the pyrolysis furnace. After combustion, a gas mixture mainly composed of carbon dioxide is obtained.

[0036] (5) The pyrolysis solid mixture obtained in step (3) is fed into a roller-driven forward cooling furnace for cooling treatment. The forward cooling furnace has the same structure as the forward pyrolysis furnace in step (3). The cooling zone is 9.0 m long, the roller spacing is 100 mm, the roller width is 1500 mm, the roller surface linear speed is 300 mm / min, the cooling time is 30 min, and room temperature water cooling is used. The cooling temperature is controlled at 20 ± 5 ºC. The cooled pyrolysis solid mixture contains glass, silicon wafers and tin-coated solder ribbons. The cooled pyrolysis solid mixture is sorted and sorted to obtain glass, silicon wafers and tin-coated solder ribbons respectively.

[0037] In this embodiment, the removal rate of the encapsulation medium in the entire recycling process is 99.95%, and the calorific values ​​of the pyrolysis oil and pyrolysis gas are 42.76 MJ / kg and 43.89 MJ / m³, respectively. 3 The recovery rate of tin-coated solder strips is 99%, the recovery rate of silicon wafers is 99%, and the glass recovery rate is 100% and in its intact state.

[0038] Example 2:

[0039] Same as Example 1, except that:

[0040] The complete decommissioned double-glass crystalline silicon photovoltaic laminate obtained in step (2) has a length of 2400 mm and a width of 1200 mm.

[0041] In step (3), the pyrolysis temperature is controlled at 550±5℃ and the pyrolysis time is 30 min.

[0042] The entire recycling process achieved a 99.67% removal rate of the encapsulation medium, with calorific values ​​of 41.55 MJ / kg and 41.59 MJ / m³ for the pyrolysis oil and gas, respectively. 3 The recovery rate of tin-coated solder strips is 99%, the recovery rate of silicon wafers is 99%, and the glass recovery rate is 100% and in its intact state.

[0043] Example 3:

[0044] Same as Example 1, except that:

[0045] The complete decommissioned double-glass crystalline silicon photovoltaic laminate obtained in step (2) has a length of 2400 mm and a width of 1200 mm.

[0046] In step (3), the pyrolysis temperature is controlled at 600±5℃ and the pyrolysis time is 20 min.

[0047] The entire recycling process achieved a 99.38% removal rate of the encapsulation medium, with calorific values ​​of 42.02 MJ / kg for pyrolysis oil and 43.34 MJ / m³ for pyrolysis gas. 3The recovery rate of tin solder strips is 99%, the recovery rate of silicon wafers is 99%, and the glass recovery rate is 100% and in its intact state.

[0048] Example 4:

[0049] Same as Example 1, except that:

[0050] The complete decommissioned double-glass crystalline silicon photovoltaic laminate obtained in step (2) has a length of 350 mm and a width of 350 mm.

[0051] In step (3), the pyrolysis temperature is controlled at 550±5℃ and the pyrolysis time is 20 min.

[0052] The entire recycling process achieved a 99.37% removal rate of the encapsulation medium, with calorific values ​​of 40.62 MJ / kg and 40.92 MJ / m³ for the pyrolysis oil and gas, respectively. 3 The recovery rate of tin-coated solder strips is 99%, the recovery rate of silicon wafers is 99%, and the glass recovery rate is 100% and in its intact state.

[0053] The above description of the embodiments is only for the purpose of helping to understand the technical solution and core idea of ​​the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made to the present invention without departing from the principle of the present invention, and these improvements and modifications also fall within the protection scope of the claims of the present invention.

Claims

1. A method for high efficiency thermal disassembly of decommissioned dual- glass silicon photovoltaic modules, characterized in that, Includes the following steps: (1) The retired double-glass crystalline silicon photovoltaic module is mechanically disassembled to separate the aluminum frame, junction box and double-glass crystalline silicon photovoltaic laminate, wherein the double-glass crystalline silicon photovoltaic laminate includes a front glass plate, a first encapsulation medium, a silicon wafer, a second encapsulation medium and a rear glass plate connected in sequence. (2) The double-glass crystalline silicon photovoltaic laminate obtained in step (1) is initially judged and classified into complete laminates and broken laminates; (3) The complete or broken laminate obtained in step (2) is sent into a pyrolysis reaction vessel for pyrolysis treatment. The pyrolysis reaction vessel is a roller-driven forward pyrolysis furnace to obtain pyrolysis oil, pyrolysis gas and pyrolysis solid mixture. (4) The pyrolysis oil and pyrolysis gas obtained in step (3) are transported to the combustion chamber for combustion to provide heat for the pyrolysis reaction vessel. After combustion, a gas mixture mainly composed of carbon dioxide is obtained. (5) The pyrolysis solid mixture obtained in step (3) is sent to a cooling reaction vessel for cooling treatment, and then sorted and sorted to obtain glass, silicon wafers and tin-coated solder ribbons.

2. The method according to claim 1, characterized in that, The first or second encapsulating medium is selected from one of EVA, POE, and EVA / POE / EVA co-extruded composite film.

3. The method according to claim 1 or 2, characterized in that, The conditions for the pyrolysis treatment in step (3) are: pyrolysis temperature of 300℃-800℃, pyrolysis time of 10-120 min, heating method of electric heating or natural gas heating, pyrolysis atmosphere of nitrogen atmosphere, and the first and second packaging media are decomposed into pyrolysis oil and pyrolysis gas through pyrolysis treatment.

4. The method according to claim 3, characterized in that, The conditions for the pyrolysis treatment in step (3) are: pyrolysis temperature of 500℃-600℃ and pyrolysis time of 20-30 min.

5. The method according to claim 1 or 2, characterized in that, The roller spacing of the roller-driven forward pyrolysis furnace described in step (3) is 50-150 mm, the width of the heating area of ​​the pyrolysis furnace is 1500-2500 mm, the length is 9-80 m, and the roller surface linear speed is 100-2000 mm / min.

6. The method according to claim 1 or 2, characterized in that, The pyrolysis oil in step (4) has a calorific value ranging from 30 to 60 MJ / kg, and the pyrolysis gas has a calorific value ranging from 30 to 60 MJ / m 3 .

7. The method according to claim 1, characterized in that, The cooling reaction vessel mentioned in step (5) is a roller-driven forward cooling furnace with the same structure as in step (3). Its cooling area width is 1500-2500 mm, its length is 9-80 m, its roller surface linear speed is 100-2000 mm / min, its cooling time is 10-120 min, and its cooling method is water cooling.

8. The method according to claim 1, characterized in that, The cooling temperature in step (5) is 15℃-25℃.

9. The application of the method of claim 1 in the separation and recycling of decommissioned double-glass crystalline silicon photovoltaic modules.

Images