Resource recycling method and system for photovoltaic module

Abstract

The invention relates to the technical field of photovoltaic module recycling, and discloses a photovoltaic module resource recycling method which comprises the following steps: disassembling a photovoltaic module to obtain a photovoltaic panel and a peripheral module; the photovoltaic panel is fed into a pyrolyzing furnace to be pyrolyzed, a solid product, pyrolysis oil and pyrolysis gas are obtained, and the pyrolysis gas is fed into the pyrolyzing furnace to serve as fuel; sorting the solid product to obtain a soldering tin strip, glass fragments, a battery panel silicon wafer and ash; the glass fragments are fed into a high-temperature melting furnace to be melted into liquid fluid, and the melted liquid fluid is sprayed out through a nozzle of a centrifugal machine to form glass fiber cotton; an acid pickling solution is added into the ash residues, leaching liquid and solid residues are obtained after full reaction, elemental silver is obtained after the leaching liquid is treated, and silicon powder is obtained after the solid residues are subjected to phosphoric acid treatment. According to the invention, the problems of high energy consumption, serious pollution and incapability of fully recycling the waste photovoltaic panel in the existing waste photovoltaic panel recycling method are solved, and the full-component high-value recycling of the waste photovoltaic panel is realized.

Description

Technical Field

[0001] The present invention relates to the technical field of photovoltaic component recycling, and in particular to a photovoltaic component resource recycling method and a photovoltaic component resource recycling system using the method. Background Art

[0002] With the guidance of national policies and the vigorous development of clean energy technology, photovoltaic power stations and photovoltaic panels that use solar energy as energy have been manufactured and used in large quantities. However, crystalline silicon photovoltaic modules have a certain service life. When the power generation efficiency of photovoltaic modules drops to a certain level, they can no longer be used. At this time, retired photovoltaic modules need to be recycled and reused as resources.

[0003] The main recyclable parts of crystalline silicon photovoltaic modules include aluminum in the outer aluminum frame (recycling rate is 10%-15%) and various materials in photovoltaic laminates. Among them, glass is the largest part of recycling, accounting for 65%-75%; organic matter such as EVA film and plastic accounts for 10%, which is also one of the valuable recycling materials; in addition, there are other recyclable components such as valuable element particles.

[0004] Since there is a photovoltaic film on the photovoltaic panel that adheres the cell to the photovoltaic glass and the back panel, if it is not removed, it will seriously affect the recycling of the photovoltaic panel. Therefore, it is often necessary to heat the photovoltaic panel as a whole to remove the film. For example, the Chinese patent "A process for comprehensive recycling of waste photovoltaic panels" with publication number CN116984342A, the method mechanically disassembles the waste photovoltaic panel, recovers the aluminum frame and the junction box, and then calcines the remaining photovoltaic components to obtain the calcined product; the calcined product is physically sorted, and the remaining crystalline silicon wafers after the photovoltaic welding strip and the photovoltaic glass are recovered to prepare crystalline silicon powder; the crystalline silicon powder is leached with a sulfuric acid solution with a concentration of 2 to 4 mol / L to obtain an aluminum-rich solution and a leached residue A, and the aluminum-rich solution is concentrated and crystallized to obtain aluminum sulfate; the leached residue A is washed and placed in a nitric acid solution for leaching to obtain a silver-rich solution and a leached residue B, and the silver-rich solution is reduced and then recovered to obtain Ag element; the leached residue B is mixed with a phosphoric acid solution, the silicon nitride layer is removed, and pure silicon powder is obtained.

[0005] The above recycling method of waste photovoltaic panels adopts calcination, which has high energy consumption, large amount of flue gas and complex flue gas composition, and is difficult and costly to treat. There may also be dioxin problems. Especially for glass, which accounts for 65%-75%, the performance of the recycled glass drops sharply after calcination, and it can only be downgraded and difficult to recycle at high value. Therefore, a method with lower energy consumption, more environmental protection and high value recycling of waste photovoltaic components is needed. Summary of the invention

[0006] In view of the problems existing in the prior art: the existing recycling and treatment methods for waste photovoltaic panels have the problems of high energy consumption, serious pollution, and inability to fully recycle waste photovoltaic panels, the purpose of the present invention is to provide a method for recycling and utilizing photovoltaic modules, which gradually performs mechanical disassembly, pyrolysis, physical sorting, chemical treatment and melt fiberization on photovoltaic modules. Among them, the amount of flue gas produced by pyrolysis is small, and the pyrolysis gas produced by pyrolysis can be used as a heating fuel. The sorted glass fragments can be melt-fiberized to obtain high-value-added glass fiber wool, and the ash residue is subjected to a series of chemical processes to obtain high-quality silicon powder raw materials and precious metals, realizing the high-value recycling of all components of waste photovoltaic panels.

[0007] To achieve the above object, the technical solution of the present invention is: A photovoltaic module resource recycling method and system, comprising the following steps: S1: Disassemble the photovoltaic modules to obtain photovoltaic panels and peripheral components that can be directly recycled; S2: The photovoltaic panel is sent into a pyrolysis furnace for pyrolysis at a temperature of 350-800°C to obtain solid products, pyrolysis oil and pyrolysis gas, wherein the pyrolysis gas is sent into the pyrolysis furnace as fuel; S3: Physically sorting the solid products to obtain solder ribbon, glass fragments, solar panel silicon wafers and ash; S4: feeding the glass fragments into a high-temperature melting furnace with an internal temperature of 1100-1800° C. to melt the glass fragments into liquid fluid, and the molten liquid fluid is ejected through a centrifuge nozzle to form glass fiber wool; S5: adding pickling solution to the ash and obtaining a leaching solution and a solid slag material after sufficient reaction, reducing the leaching solution to obtain silver element, and treating the solid slag material with phosphoric acid to obtain silicon powder.

[0008] The present invention is further configured as follows: in step S1, the photovoltaic components are disassembled by mechanical disassembly, and the obtained peripheral components include an aluminum frame, a cable and a junction box, and the photovoltaic panel can be broken at the same time.

[0009] The present invention is further configured as follows: the pyrolysis gas obtained in step S2 is first subjected to alkali washing and purification treatment to remove acidic gases in the pyrolysis gas before being sent to the pyrolysis furnace, and the pyrolysis oil can be sent to the pyrolysis furnace as fuel for use in the pyrolysis furnace.

[0010] The present invention is further configured as follows: in step S2, the material temperature in the pyrolysis furnace is controlled to be 450-650°C, and the reaction duration is 30-45 minutes.

[0011] The present invention is further configured as follows: Step S3 comprises the following steps: S301: sorting the solid product to obtain solder strips and remaining solids; S302: Screening the remaining solid to obtain glass fragments and other powders; S303: Other powders are air-selected to obtain solar panel silicon wafers and ash.

[0012] The present invention is further configured as follows: in the process of melting the glass fragments in step S4, additives including quartz sand, limestone and defoaming agent are added to the high-temperature melting furnace, and the mass ratio of the added amount of quartz sand, limestone and defoaming agent to the glass fragments is a:b:c:d; wherein, when the value of d is 100, the values ​​of a and b are both 1-5, and the value of c is 0.1-0.3.

[0013] The present invention is further configured as follows: the rotation speed of the centrifuge in step S4 is 3000-4000 rpm, and the centrifugation duration is 1-5 minutes.

[0014] The present invention is further configured as follows: the pickling solution in step S5 is nitric acid or sulfuric acid or hydrogen peroxide or a mixed solution formed by any combination of the three.

[0015] The present invention is further configured as follows: in step S2, a continuous rotary pyrolysis furnace is used for pyrolysis in a fully sealed manner, and the entire furnace is protected by an inert gas.

[0016] The present invention also provides a photovoltaic module resource recycling system, which recycles the photovoltaic modules according to any one of the above methods.

[0017] In summary, the beneficial effects achieved by the present invention are as follows: (1) The pyrolysis method is used to decompose the organic components such as EVA film and plastic in the photovoltaic panel. This not only removes the film in the photovoltaic panel to prevent it from affecting the subsequent processes, but also can recycle the pyrolysis oil and pyrolysis gas, avoiding the problem of large amounts of flue gas polluting the environment and increasing treatment costs due to incineration. At the same time, it also avoids the problem that the performance of the glass recovered by the traditional calcination method drops sharply and can only be downgraded for use; (2) The pyrolysis oil and pyrolysis gas obtained by the pyrolysis method can be recycled. The pyrolysis oil can be exported as a separate energy product, or it can be used together with the pyrolysis gas as energy for the pyrolysis furnace, thereby reducing the pyrolysis furnace's consumption of external energy; (3) The technology of preparing glass fiber wool by high-temperature melting is adopted, and the glass fragments in the solid product obtained by pyrolysis are used as the main raw material for preparing high-value-added glass fiber wool. This not only effectively recycles the glass fragments, but also produces glass fiber wool products with excellent performance, which can be widely used in the fields of construction, automobiles, aerospace, etc. (4) For the entire photovoltaic module, the aluminum frame, cables and junction box are recycled through mechanical disassembly; the pyrolysis oil and pyrolysis gas generated by the organic components are recycled through pyrolysis; the solder strips and solar panel silicon wafers are obtained by sorting the pyrolysis solid products; silicon powder and precious metal silver are recovered through acid washing, purification and reduction of the ash, and glass fragments are used to produce glass fiber wool, thus realizing the high-value utilization of all components of the waste photovoltaic module. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the specification will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present invention. For ordinary technicians in this field, other drawings can also be obtained based on these drawings.

[0019] Figure 1 This is a schematic diagram of the process flow of the photovoltaic module resource recycling method in the first embodiment of the present invention; Figure 2 This is a schematic diagram of the composition structure of the photovoltaic component resource recycling system in Example 2 of the present invention. DETAILED DESCRIPTION

[0020] The following is a clear and complete description of the technical solutions in the embodiments of the present invention in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present invention.

[0021] Embodiment 1

[0022] As attached Figure 1 As shown, a method for recycling photovoltaic components comprises the following steps: S1: Disassemble photovoltaic modules to obtain photovoltaic panels and peripheral components that can be directly recycled.

[0023] Mechanical disassembly of scrapped crystalline silicon photovoltaic modules is a pre-treatment of photovoltaic modules. It can directly recycle aluminum frames and junction boxes, as well as some cables and other peripheral components to the greatest extent, while avoiding the additional burden of peripheral components on the subsequent pyrolysis process. During the disassembly process, the photovoltaic panels can be crushed to a certain extent according to the requirements of the subsequent pyrolysis process.

[0024] In this embodiment, 800 kg of waste photovoltaic components are disassembled to obtain photovoltaic panels with a net weight of about 760 kg, of which the weight ratio of peripheral components such as aluminum frames and junction boxes is about 5%.

[0025] S2: The photovoltaic panel is sent into a pyrolysis furnace for pyrolysis at a temperature of 350-800°C to obtain solid products, pyrolysis oil and pyrolysis gas.

[0026] Pyrolysis treatment is to indirectly heat the photovoltaic panel in an oxygen-free or oxygen-deficient state, so that the organic components such as plastics, EVA films (ethylene-vinyl acetate copolymers) therein are completely decomposed. In order to ensure that the organic matter in the photovoltaic panel is fully decomposed and to avoid the material staying in the pyrolysis furnace for too long, the present invention adopts a continuous rotary pyrolysis furnace that can accurately control the pyrolysis time, and diesel is used as the main heat source. The pyrolysis furnace adopts jacket heating technology, and the high-temperature hot flue gas circulates in the shell side, and the pyrolysis material flows in the furnace in the opposite direction to the shell flue gas. The material temperature in the pyrolysis furnace is controlled at 450-650℃, and the reaction duration is 30-45min, which ensures that the pyrolysis time is sufficient and avoids the pyrolysis time being too long. In this embodiment, the material temperature is controlled at 450-550℃, and the reaction time is set to 35 minutes. After pyrolysis treatment, organic components such as adhesives are completely removed, which not only ensures the cleanliness of solid products in subsequent processes, but also helps to improve the quality of subsequent products.

[0027] The above-mentioned S2 process performs pyrolysis in a fully sealed manner. In order to ensure the safety of the pyrolysis equipment, the internal furnace of the pyrolysis furnace is protected by an inert gas, such as nitrogen, carbon dioxide, etc., so as to control the oxygen content in the internal furnace of the pyrolysis furnace.

[0028] After pyrolysis, 760kg of photovoltaic panels produce pyrolysis oil and about 35m³ of pyrolysis gas. Pyrolysis oil can be exported as a separate energy product, or it can be used together with pyrolysis gas as energy for pyrolysis furnaces, thereby reducing the consumption of external energy by pyrolysis furnaces. In particular, in order to prevent the acidic gas in the pyrolysis gas from corroding equipment and pipelines, the pyrolysis gas needs to be deacidified before entering the pyrolysis furnace for combustion to remove the acidic gas components in the pyrolysis gas. Specifically, the pyrolysis gas is sprayed with 10% alkaline solution for deacidification, and the deacidified pyrolysis gas is sent to the pyrolysis furnace as fuel. After the pyrolysis process of 760kg of photovoltaic panels is completed, the total amount of flue gas generated is about 400m³, which mainly contains carbon dioxide, water vapor, nitrogen and nitrogen oxides, and meets the emission standards after flue gas treatment.

[0029] S3: Physically sort the solid products to obtain solder ribbon, glass fragments, solar panel silicon wafers and ash.

[0030] After pyrolysis treatment, the glass fragments and silicon wafers in the photovoltaic panels are effectively separated, and the solid products obtained include glass fragments, solder ribbons, etc. In order to fully separate the different substances in the solid products, the following steps are required: S301: sorting the solid product to obtain solder ribbon and remaining solid.

[0031] The solder ribbon can be separated from the solid product by hook separation or magnetic separation. In this embodiment, the solder ribbon is recovered by combining vibration screening and magnetic separation to obtain about 13 kg of solder ribbon and residual solids.

[0032] S302: The remaining solid is screened to obtain glass fragments and other powders.

[0033] The remaining solids were screened by a screw conveyor with mesh holes, the mesh holes of which were 0.2-2 mm long holes. Approximately 500 kg of glass fragments and approximately 247 kg of other powders were separated.

[0034] S303: Other powders are air-selected to obtain solar panel silicon wafers and ash.

[0035] Air separation is a method of removing impurities by wind force, using the difference in suspension speed between materials and impurities. The present invention uses an air separator or air flow separator to separate other powders, and obtains about 160kg of solar panel silicon wafers and about 87kg of ash.

[0036] The ash treatment process is S5: adding pickling solution to the ash to obtain a leachate and solid slag after sufficient reaction. The leachate is then concentrated, purified, and reduced to obtain silver, and the solid slag is treated with phosphoric acid and purified to obtain silicon powder.

[0037] The pickling solution is nitric acid or sulfuric acid or hydrogen peroxide, or a mixed solution formed by any combination of the three, such as a mixed solution of nitric acid and hydrogen peroxide or a mixed solution of sulfuric acid and hydrogen peroxide, and a mixed solution of the three. The mass ratio of the addition amount of the pickling solution to the ash is e:1, and the value range of e is 2-4.

[0038] In this embodiment, the pickling solution is a mixed solution of nitric acid (concentration 68%), sulfuric acid (concentration 98%) and hydrogen peroxide (concentration 30%) in a volume ratio of 1:0.75:1. The mass ratio of the amount of pickling solution added to the ash is 3:1, and the leaching reaction lasts for 2 hours to obtain a silver-containing leachate and solid slag. After the silver-containing leachate is concentrated, purified and reduced, the precious metal silver is obtained, and the leaching rate of silver reaches 99.8%; and after the solid slag is treated with phosphoric acid and purified in the prior art, the purity of silicon can be increased to more than 98%, and about 60kg of high-purity silicon powder is obtained.

[0039] The processing step for the glass fragments is S4: the glass fragments are sent into a high-temperature melting furnace with an internal temperature of 1100-1800° C. to melt the glass fragments into liquid fluid, and the molten liquid fluid is sprayed out through a centrifuge nozzle to form glass fiber wool.

[0040] The use of high-temperature melting to prepare glass fiber wool is a deep processing of recycled glass fragments. The glass fragments need to be fed into a high-temperature melting furnace, and during the melting process of the glass fragments, additives including quartz sand, limestone and defoaming agent need to be added to the high-temperature melting furnace, and the mass ratio of the added amount of quartz sand, limestone and defoaming agent to the glass fragments is a:b:c:d; wherein, when the value of d is 100, the values ​​of a and b are both 1-5, and the value of c is 0.1-0.3. The high-temperature melting furnace can choose a low-capacity electric melting furnace with a single furnace processing capacity of 1-5 tons / day, or a gas melting furnace with a single furnace processing capacity of 5-100 tons / day.

[0041] This embodiment uses an electric melting furnace, the temperature is set to 1500°C, and the melting time is controlled at 40 minutes. At the same time, an appropriate amount of quartz sand, limestone and defoaming agent are added as additives, wherein the mass ratio of the amount of quartz sand, limestone and defoaming agent added to the glass fragments is 4:1:0.1:100. The molten high-temperature liquid fluid is ejected at high speed through the nozzle of the centrifuge. Under the action of centrifugal force, the molten liquid will be thrown into fine fibers, namely glass fiber cotton. The centrifuge speed is 3000-4000 rpm, and the centrifugation duration is 1-5 minutes. Finally, the impurities are removed by the slag remover, and the fiber cotton after slag removal is sent to the cotton collecting chamber for centralized collection, and finally a high-quality glass fiber cotton product with a slag ball mass content of less than 0.5%, an average fiber diameter of 3-5 microns, and a fiber length of 5-10 mm is obtained.

[0042] The above-mentioned method for recycling and utilizing photovoltaic components uses pyrolysis to decompose the organic components in the photovoltaic panels, which has low energy consumption, and both the pyrolysis oil and pyrolysis gas can be recycled to further reduce energy consumption; at the same time, the amount of flue gas generated by pyrolysis is small, and there is no harmful gas in the flue gas, which is more environmentally friendly. As for the entire photovoltaic component, the aluminum frame, cable and junction box are recycled through mechanical disassembly; the pyrolysis oil and pyrolysis gas generated by the organic components are recycled through pyrolysis; the solder strip and the silicon wafer of the solar panel are obtained by sorting the solid products of pyrolysis; the silicon powder and the precious metal silver are recovered by acid washing, purification and reduction of the ash, and the glass fragments are processed to produce glass fiber wool, thereby realizing the high-value utilization of all components of the waste photovoltaic component.

[0043] Embodiment 2

[0044] As attached Figure 2 As shown, the present invention also discloses a photovoltaic component resource recycling system, including a pretreatment unit, a pyrolysis unit, a sorting module, a glass processing unit and a chemical treatment unit.

[0045] The system in this embodiment recycles and utilizes photovoltaic modules according to the process method in embodiment one. Specifically, the pretreatment unit is used to mechanically disassemble waste photovoltaic modules, and the pyrolysis unit is used to pyrolyze photovoltaic panels. The sorting module includes a first sorting unit for sorting solid products and a second sorting unit for air sorting other powders. The glass processing unit is used to melt glass fragments to prepare glass fiber wool; the chemical treatment unit is used to treat ash and solid slag with chemical reagents.

[0046] Embodiment 3

[0047] The present invention also discloses a method for recycling photovoltaic modules. Different from the first embodiment, the method uses incineration instead of pyrolysis to remove organic components such as adhesive films, and does not perform deep processing on the recycled glass fragments.

[0048] Specifically, in this embodiment, about 600 kg of waste photovoltaic panels are obtained after disassembling the waste photovoltaic modules, and the photovoltaic panels are sent to the incinerator. The furnace uses air to assist combustion, and the incineration temperature is set to 800°C to ensure that the organic matter is completely burned. The total amount of flue gas generated during the incineration process is about 1000 m³. In addition to a large amount of carbon dioxide and water vapor, the flue gas also contains a small amount of organic benzene-related harmful gases that did not appear in the pyrolysis process in Example 1, which need to be removed by activated carbon adsorption.

[0049] From the analysis of Example 1 and Example 3, it can be seen that for photovoltaic panels of the same quality, the amount of flue gas generated by pyrolysis is significantly less than the amount of flue gas generated by incineration, and the flue gas generated by pyrolysis does not contain harmful organic benzene-related gases, so there is no need to add additional adsorption devices, and the cost of flue gas treatment is lower.

[0050] Although embodiments of the present invention have been described, additional changes and modifications may be made to these embodiments by those skilled in the art once the basic inventive concepts are known. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present invention. Obviously, those skilled in the art may make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these modifications and variations.

Claims

1. A method for recycling photovoltaic modules, characterized in that: The steps include: S1: Disassemble the photovoltaic modules to obtain photovoltaic panels and peripheral components that can be directly recycled; S2: The photovoltaic panel is sent into a pyrolysis furnace for pyrolysis at a temperature of 350-800°C to obtain solid products, pyrolysis oil and pyrolysis gas, wherein the pyrolysis gas is sent into the pyrolysis furnace as fuel; S3: Physically sorting the solid products to obtain solder ribbon, glass fragments, solar panel silicon wafers and ash; S4: feeding the glass fragments into a high-temperature melting furnace with an internal temperature of 1100-1800° C. to melt the glass fragments into liquid fluid, and the molten liquid fluid is ejected through a centrifuge nozzle to form glass fiber wool; S5: adding pickling solution to the ash and obtaining a leaching solution and a solid slag material after sufficient reaction, reducing the leaching solution to obtain silver element, and treating the solid slag material with phosphoric acid to obtain silicon powder.

2. The method for recycling photovoltaic modules according to claim 1, characterized in that: In step S1, the photovoltaic components are disassembled by mechanical disassembly, and the obtained peripheral components include aluminum frames, cables and junction boxes. At the same time, the photovoltaic panels can be broken.

3. The method for recycling photovoltaic modules according to claim 1, characterized in that: The pyrolysis gas obtained in step S2 is first subjected to alkali washing and purification treatment before being sent to the pyrolysis furnace to remove acidic gases in the pyrolysis gas. The pyrolysis oil can be sent to the pyrolysis furnace as fuel for use in the pyrolysis furnace.

4. The method for recycling photovoltaic modules according to claim 1, characterized in that: In step S2, the material temperature in the pyrolysis furnace is controlled to be 450-650°C, and the reaction duration is 30-45 minutes.

5. The method for recycling photovoltaic modules according to claim 1, characterized in that: Step S3 includes the following steps: S301: sorting the solid product to obtain solder strips and remaining solids; S302: Screening the remaining solid to obtain glass fragments and other powders; S303: Other powders are air-selected to obtain solar panel silicon wafers and ash.

6. The method for recycling photovoltaic modules according to claim 1, characterized in that: In the process of melting the glass fragments in step S4, additives including quartz sand, limestone and defoaming agent are added to the high-temperature melting furnace, and the mass ratio of the added amount of quartz sand, limestone and defoaming agent to the glass fragments is a:b:c:d; wherein, when the value of d is 100, the values ​​of a and b are both 1-5, and the value of c is 0.1-0.

3.

7. The method for recycling photovoltaic modules according to claim 1, characterized in that: The rotation speed of the centrifuge in step S4 is 3000-4000 rpm, and the centrifugation duration is 1-5 minutes.

8. The method for recycling photovoltaic modules according to claim 1, characterized in that: The pickling solution in step S5 is a mixed solution formed by nitric acid, sulfuric acid, hydrogen peroxide, or any combination of the three.

9. The photovoltaic module resource recycling method according to claim 1, characterized in that: In step S2, a continuous rotary pyrolysis furnace is used for pyrolysis in a fully sealed manner, and the entire furnace is protected by an inert gas.

10. A photovoltaic module resource recycling system, characterized in that: Photovoltaic components are recycled according to the method described in any one of claims 1 to 9.

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