Method for recycling retired photovoltaic module and fixing carbon dioxide

Abstract

The invention provides a method for recycling retired photovoltaic modules and fixing carbon dioxide. The method comprises the following steps: S1, disassembling an out-of-service photovoltaic module to obtain a photovoltaic laminated part; the photovoltaic laminated piece comprises a packaging adhesive film and a glass substrate; s2, performing pyrolysis on the photovoltaic laminated part to obtain pyrolysis tail gas; wherein the pyrolysis tail gas comprises carbon dioxide gas and water; and S3, culturing algae by taking carbon dioxide gas as a carbon source to realize fixation of carbon dioxide. According to the method, recycling of the retired photovoltaic module can be organically combined with biological carbon sequestration, so that emission of greenhouse gases is reduced while the packaging adhesive film is recycled, and the resource recycling rate can be increased. Through the biological carbon sequestration effect of algae, carbon dioxide gas generated by pyrolyzing the packaging adhesive film is effectively utilized, so that the gas source required for culturing the algae is reduced, and the cost can be reduced.

Description

Technical Field

[0001] The present invention relates to the field of environmental protection technology, and in particular to a method for recycling and processing retired photovoltaic components and fixing carbon dioxide. Background Art

[0002] With the vigorous development of the global photovoltaic industry, the industry is accelerating upgrading and equipment replacement, and new energy equipment will face the problem of mass retirement. At present, there are cases of premature retirement of photovoltaic modules caused by natural disasters, technological iterations, and poor quality. It is estimated that the number will reach 1.05 million tons and 20 million tons in 2025 and 2050 respectively. Starting from 2030, domestic photovoltaic modules will face large-scale retirement. The high-value recycling, harmless treatment and pollution prevention of waste modules are urgent issues that need to be solved in advance. If clean energy is not considered for clean recycling at the end of its life cycle, it goes against the original purpose of clean energy. At the beginning of its design, photovoltaic modules adopted a flat structure to ensure the utilization rate of light sources to obtain sufficient light sources, resulting in low unit volume utilization during recycling, which brought difficulties to subsequent recycling and treatment; and to prevent the outdoor extreme environment from damaging photovoltaic modules, the protective components of photovoltaic modules are composed of aluminum frames and photovoltaic glass, which account for a large proportion. Excluding these, the weight of the remaining core components usually accounts for less than 15%. Despite this, photovoltaic modules still need to be disassembled and reused to complete the clean recycling of the last link in the life cycle of clean energy. Due to its low economic value, encapsulation film has not been properly disposed of, but if a large amount of EVA (polyethylene-vinyl acetate copolymer) film is not treated in an environmentally friendly manner, it will cause serious environmental problems.

[0003] On this basis, recycling and processing of encapsulation films in retired photovoltaic modules is of great significance for the effective utilization of carbon dioxide, reducing environmental pollution and waste of resources. Summary of the invention

[0004] The main purpose of the present invention is to provide a method for recycling and processing retired photovoltaic modules and fixing carbon dioxide, so as to solve the problems in the prior art that the recycling rate of packaging films is low, the environment is polluted, and it is difficult to organically combine recycling and fixation of carbon dioxide, thereby realizing the recycling of packaging films and the effective utilization of carbon dioxide.

[0005] In order to achieve the above-mentioned objectives, the present invention provides, on one hand, a method for recycling and processing retired photovoltaic modules and fixing carbon dioxide, the method comprising: step S1, disassembling retired photovoltaic modules to obtain photovoltaic laminates; the photovoltaic laminates include packaging films and glass substrates; step S2, pyrolyzing the photovoltaic laminates to obtain pyrolysis exhaust gas; wherein the pyrolysis exhaust gas includes carbon dioxide gas and water; step S3, culturing algae with carbon dioxide gas as a carbon source to achieve carbon dioxide fixation.

[0006] Furthermore, step S1 includes: disassembling the frame, junction box, back plate, battery cell, welding ribbon and bus bar in the retired photovoltaic module to obtain a photovoltaic laminate.

[0007] Furthermore, the pyrolysis temperature is 450-650° C., and the time is 30-60 min.

[0008] Furthermore, microwave heating, tube furnace heating, laser heating or electric knife heating is used for pyrolysis.

[0009] Furthermore, the power of microwave heating is 400-1000 W, preferably 800-1000 W, and the frequency is 915 or 2450 MHz, preferably 2450 MHz.

[0010] Furthermore, the pyrolysis is carried out in an oxygen-containing atmosphere, and the gaseous components in the pyrolysis tail gas include carbon dioxide gas; between step S2 and step S3, it also includes: oxygen-enriched combustion of the pyrolysis tail gas, so that all the gaseous components that are not fully oxidized are converted into carbon dioxide gas to obtain combustion tail gas; preferably, the above method also includes: compressing the combustion tail gas.

[0011] Furthermore, the volume percentage of oxygen in the oxygen-containing atmosphere is 10 to 25 vol%.

[0012] Furthermore, the volume of the compressed gas is 10-25% of the volume of the combustion exhaust gas.

[0013] Furthermore, the pyrolysis is carried out in the air, and the gas phase components in the pyrolysis tail gas include carbon dioxide gas and hydrocarbons; between step S2 and step S3, it also includes: treating the pyrolysis tail gas by catalytic oxidation to obtain a mixture of carbon dioxide gas and organic matter, wherein the organic matter is selected from one or more of C1-C5 aldehydes, C1-C5 carboxylic acids and C1-C5 alkanes; separating the carbon dioxide gas and the organic matter, acid-washing the organic matter to obtain an acid-washing product, or esterifying the organic matter to obtain an esterification product, and recovering and treating the acid-washing product and the esterification product.

[0014] Furthermore, the catalytic oxidation method is electrocatalytic oxidation or chemical catalytic oxidation, and the oxidant used in the catalytic oxidation method is selected from one or more of the group consisting of potassium permanganate, ozone and air oxidation.

[0015] Furthermore, the organic matter is methane; the method further comprises: condensing and recovering the organic matter and using it for combustion to provide heat, and returning the generated waste heat to step S2 and / or step S3; preferably, a heat exchanger is used to return the waste heat.

[0016] Furthermore, the pyrolysis tail gas is filtered and dried before step S3.

[0017] Furthermore, a dust collector is used for filtration, or membrane separation technology is used for filtration.

[0018] Furthermore, a desiccant is used for drying; preferably, the desiccant is one or more selected from the group consisting of anhydrous calcium chloride, silica gel and activated carbon.

[0019] Furthermore, step S3 includes: introducing carbon dioxide gas into the culture medium of the algae to culture the algae.

[0020] Further, the algae is selected from one or more of the group consisting of cyanobacteria, microscalyx, pseudobranch algae, coccophyte, nostoc and anabaena.

[0021] Furthermore, the algae is cyanobacteria, the pH of the culture medium is 7.5-9.0, and the total inorganic carbon concentration is 100-550 mmol / L; or, the algae is Microscalyx, the pH of the culture medium is 4-8, and the total inorganic carbon concentration is 10-100 mmol / L; or, the algae is Pseudocranium, the pH of the culture medium is 5.5-7.5, and the total inorganic carbon concentration is 10-100 mmol / L; or, the algae is Chlorella, the pH of the culture medium is 5.5-7.5, and the total inorganic carbon concentration is 10-100 mmol / L.

[0022] Further, the cultivation is carried out in a photobioreactor.

[0023] Furthermore, step S3 also includes: using a pH monitoring device and an inorganic carbon monitoring device to monitor the pH of the culture medium in real time, and when it is monitored that the pH is lower than the lower limit of the pH range required by the algae, an alarm signal is generated, and the intelligent control system closes the solenoid valve after receiving the alarm signal, and stops the introduction of carbon dioxide gas. When it is monitored that the pH is higher than the upper limit of the pH range required by the algae, a pH adjuster is added to adjust the pH to the required pH range.

[0024] Furthermore, the pH regulator is selected from an acidic compound, an alkaline compound or a neutral buffer; preferably, the acidic compound is selected from one or more of the group consisting of HCl, H2SO4 and citric acid, the alkaline compound is selected from NaOH and / or KOH, and the neutral buffer is selected from Tris-HCl buffer or Tris-phosphate buffer.

[0025] Furthermore, the packaging film is selected from PEVA film, POE film or EPE film.

[0026] By applying the technical solution of the present invention, the above method of the present application can organically combine the recycling of retired photovoltaic modules with biological carbon fixation, so that the packaging film can be recycled while reducing greenhouse gas emissions, which can improve the recycling rate of resources. By utilizing the biological carbon fixation effect of algae, the carbon dioxide gas generated by pyrolysis of the packaging film is effectively utilized, thereby reducing the gas source required for cultivating algae and reducing costs. In addition, the cultured algae can be used to form biological crusts or algae crusts, which is of great significance for desert control. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The drawings constituting a part of the present application are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0028] Figure 1 The present invention shows a process flow chart for recycling and treating retired photovoltaic modules and fixing carbon dioxide;

[0029] Figure 2 The curves showing the change of inorganic carbon components and pH in the algae culture medium are shown;

[0030] Figure 3 A schematic flow chart showing the monitoring process of pH and inorganic carbon components. DETAILED DESCRIPTION

[0031] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present invention will be described in detail below in conjunction with the embodiments.

[0032] As described in the background technology, the existing packaging film has a low recycling rate and pollutes the environment. At the same time, it is difficult to organically combine recycling with the fixation of carbon dioxide to achieve the recycling of the packaging film and the effective utilization of carbon dioxide. In order to solve the above technical problems, the present application provides a method for recycling and processing retired photovoltaic modules and fixing carbon dioxide, such as Figure 1 As shown in the flowchart, the method includes: step S1, disassembling retired photovoltaic modules to obtain photovoltaic laminates; the photovoltaic laminates include packaging films and glass substrates; step S2, pyrolyzing the photovoltaic laminates to obtain pyrolysis exhaust gas; wherein the pyrolysis exhaust gas includes carbon dioxide gas and water; step S3, culturing algae with carbon dioxide gas as a carbon source to achieve carbon dioxide fixation.

[0033] The above method of the present application can organically combine the recycling of retired photovoltaic modules with biological carbon fixation, so that the packaging film can be recycled while reducing greenhouse gas emissions, which can improve the recycling rate of resources. By utilizing the biological carbon fixation effect of algae, the carbon dioxide gas generated by the pyrolysis of the packaging film is effectively utilized, thereby reducing the gas source required for cultivating algae and reducing costs. In addition, the cultivated algae can be used to form biological crusts or algae crusts, which is of great significance for the ecological management and restoration of the Shagohuang New Energy Base.

[0034] In a preferred embodiment, the disassembly in step S1 is performed by combining mechanization and automation; preferably, step S1 includes: disassembling the frame, junction box, back plate, cell, welding strip and bus bar in the retired photovoltaic module to obtain a photovoltaic laminate. The above method is conducive to improving the disassembly efficiency, improving the degree of automation, and reducing costs.

[0035] In a preferred embodiment, the pyrolysis temperature is 450-650°C and the time is 30-60 minutes. The pyrolysis temperature and time include but are not limited to the above ranges. Limiting them within the above ranges is beneficial to improving the pyrolysis efficiency of the packaging film, improving the pyrolysis effect, and increasing the carbon dioxide content in the pyrolysis tail gas, thereby facilitating the subsequent biological carbon fixation of algae.

[0036] In a preferred embodiment, microwave heating, tube furnace heating, laser heating or electric knife heating is used for pyrolysis. Compared with other heating methods, the above method is conducive to better controlling the uniform heating of the packaging film, thereby facilitating the improvement of pyrolysis efficiency and the content of carbon dioxide in the pyrolysis tail gas, thereby facilitating the subsequent biological carbon fixation of algae.

[0037] In order to further make the adhesive film heated more evenly and further improve the pyrolysis efficiency and the content of carbon dioxide in the pyrolysis exhaust gas, in a preferred embodiment, the power of the microwave heating method is 400-1000W, preferably 800-1000W, and the frequency is 915 or 2450MHz, preferably 2450MHz.

[0038] In a preferred embodiment, pyrolysis is carried out in an oxygen-containing atmosphere, and the gaseous components in the pyrolysis tail gas include carbon dioxide gas; between step S2 and step S3, it also includes: oxygen-enriched combustion of the pyrolysis tail gas, so that all the gaseous components that are not fully oxidized are converted into carbon dioxide gas to obtain combustion tail gas. In an oxygen-containing atmosphere, acetic acid, olefins, alkanes, aromatic volatiles and volatile aliphatic hydrocarbons produced by pyrolysis of the packaging film will eventually be converted into carbon dioxide gas. Oxygen-enriched combustion of the pyrolysis tail gas can further increase the concentration of carbon dioxide gas in the pyrolysis tail gas, and enrich more carbon elements in the carbon dioxide gas, which is convenient for subsequent biological carbon fixation of algae.

[0039] In a preferred embodiment, the volume percentage of oxygen in the oxygen-containing atmosphere is 10-25 vol%. The volume percentage of oxygen in the oxygen-containing atmosphere includes but is not limited to the above range, and limiting it within the above range is conducive to further increasing the generation of carbon dioxide gas.

[0040] In order to facilitate the collection and utilization of carbon dioxide gas, preferably, the above method also includes: compressing the combustion exhaust gas.

[0041] In order to further facilitate the collection and utilization of carbon dioxide gas, preferably, the volume of the compressed gas is 10-25% of the volume of the combustion tail gas.

[0042] In a preferred embodiment, pyrolysis is carried out in air, and the gaseous components in the pyrolysis tail gas include carbon dioxide gas and hydrocarbons; between step S2 and step S3, it also includes: treating the pyrolysis tail gas by catalytic oxidation to obtain a mixture of carbon dioxide gas and organic matter, the organic matter includes but is not limited to one or more of C1-C5 aldehydes, C1-C5 carboxylic acids and C1-C5 alkanes; separating carbon dioxide gas and organic matter, acid-washing the organic matter to obtain an acid-washing product, or esterifying the organic matter to obtain an esterification product, and recovering and treating the acid-washing product and the esterification product. Compared with an oxygen-containing atmosphere, the pyrolysis of the packaging film in the air will produce a pyrolysis tail gas with a more complex composition, and hydrocarbons cannot be completely converted into carbon dioxide gas. The pyrolysis tail gas is treated by catalytic oxidation to convert this part of hydrocarbons into short-chain organic matter, thereby obtaining a combustible fuel gas, which is convenient for subsequent heat utilization; at the same time, it is also beneficial to reduce environmental pollution caused by direct emission of pyrolysis tail gas.

[0043] In order to improve the treatment efficiency of pyrolysis tail gas and improve the efficiency of converting organic matter into fuel gas, preferably, the catalytic oxidation method is electrocatalytic oxidation or chemical catalytic oxidation, and the oxidant used in the catalytic oxidation method includes but is not limited to one or more of the group consisting of potassium permanganate, ozone and air oxidation.

[0044] Methane is a commonly used fuel gas with a high calorific value and is widely used in the field of heating. In a preferred embodiment, the organic matter includes but is not limited to methane.

[0045] In a preferred embodiment, the method further comprises: condensing and recovering the organic matter and using it for combustion and heat supply, and the waste heat generated is returned to step S2 and / or step S3. Condensing and recovering the above-mentioned fuel gas facilitates its heat utilization, and the waste heat generated is returned to step S2 to provide heat for the pyrolysis reaction, and the waste heat generated is returned to step S3 for algae cultivation to make the algae grow in a suitable temperature range, which is conducive to reducing energy consumption and reducing costs.

[0046] In a preferred embodiment, a heat exchanger is used to return the waste heat to step S2 and / or step S3. The use of a heat exchanger is conducive to reducing the additional heat introduced from the outside, effectively utilizing the waste heat that was originally discarded, and thus reducing costs.

[0047] In a preferred embodiment, the pyrolysis tail gas is filtered and dried before step S3. The pyrolysis tail gas generated by the pyrolysis of the packaging film also includes some solid particles and water. The filtration and drying treatment can remove these solid particles and water in turn, making it easier to use higher purity carbon dioxide gas to cultivate algae.

[0048] In order to improve the filtering effect, preferably, a dust collector is used for filtering, or membrane separation technology is used for filtering.

[0049] In order to improve the moisture removal effect, preferably, a desiccant is used for drying; preferably, the desiccant includes but is not limited to one or more of the group consisting of anhydrous calcium chloride, silica gel and activated carbon.

[0050] In a preferred embodiment, the carbon dioxide gas is cooled so that its temperature before passing into the algae culture medium is ≤ 20° C. Compared with other ranges, limiting its temperature range to the above range is conducive to reducing temperature fluctuations and reducing the impact of gas passing on the growth environment of algae.

[0051] In a preferred embodiment, step S3 includes: introducing carbon dioxide gas into the culture medium of algae to culture the algae. Algae cannot grow without a carbon source, and introducing carbon dioxide gas directly into the culture medium facilitates its recycling, thereby reducing the amount of additional carbon source introduced from the outside, and is beneficial to environmental protection.

[0052] In a preferred embodiment, the algae include but are not limited to one or more of the group consisting of cyanobacteria, microcoelenterates, pseudobranch algae, coccolithophores, nostoc algae and anabaena. Compared with other species, the use of the above algae is conducive to subsequent desert control.

[0053] Different algae require different growth environments, especially the pH of the growth environment. Figure 2 As shown, the inorganic carbon components H2CO3 and HCO3 in the algae culture medium - 、CO3 2-Changes with pH. In a preferred embodiment, the pH of the culture medium is 7.5-9.0, and the total inorganic carbon (TIC) concentration is 100-550 mmol / L; or, the algae is Microscalyx, the pH of the culture medium is 4-8, and the total inorganic carbon concentration is 10-100 mmol / L; or, the algae is Pseudoclones, the pH of the culture medium is 5.5-7.5, and the total inorganic carbon concentration is 10-100 mmol / L; or, the algae is Chlorella, the pH of the culture medium is 5.5-7.5, and the total inorganic carbon concentration is 10-100 mmol / L. For the above-mentioned specific types of algae, limiting the pH within the above-mentioned range after the carbon dioxide gas is passed into the culture medium is beneficial to the growth and reproduction of the algae, and is beneficial to improving the recovery and utilization rate of the carbon dioxide gas, thereby facilitating its application in desert control.

[0054] The photobioreactor can provide light, temperature and nutrients, and is suitable for the photosynthesis and growth and reproduction of the algae in the present application. In a preferred embodiment, the culture is carried out in a photobioreactor.

[0055] In a preferred embodiment, Figure 3 As shown, step S3 also includes: using a pH monitoring device and an inorganic carbon monitoring device to monitor the pH of the culture medium in real time, and when it is monitored that the pH is lower than the lower limit of the pH range required by the algae, an alarm signal is generated, and the intelligent control system closes the solenoid valve after receiving the alarm signal, and stops the introduction of carbon dioxide gas. When it is monitored that the pH is higher than the upper limit of the pH range required by the algae, a pH adjuster is added to adjust the pH to the required pH range.

[0056] Real-time monitoring and adjustment of pH by the above method is beneficial to further promote the growth and reproduction of algae, and to further improve the recovery and utilization rate of carbon dioxide gas, thereby facilitating its application in desert control.

[0057] The pH regulator can be any commonly used type in the art. In a preferred embodiment, the pH regulator includes but is not limited to an acidic compound, an alkaline compound or a neutral buffer; preferably, the acidic compound includes but is not limited to one or more of the group consisting of HCl, H2SO4 and citric acid, the alkaline compound includes but is not limited to NaOH and / or KOH, and the neutral buffer includes but is not limited to Tris-HCl buffer (pH adjustment range is 7.5 to 8.5) or Tris-phosphate buffer (pH adjustment range is 5.0 to 9.0).

[0058] In a preferred embodiment, the packaging film is selected from PEVA film, POE film or EPE film. The packaging film made of the above materials is particularly suitable for the above pyrolysis and recycling method provided in the present application, which is conducive to improving the pyrolysis efficiency and recycling rate of the packaging film.

[0059] The present application is further described in detail below in conjunction with specific embodiments. These embodiments should not be construed as limiting the scope of protection claimed in the present application.

[0060] Example 1

[0061] A method for recycling and treating retired photovoltaic modules and fixing carbon dioxide, comprising:

[0062] (1) removing an aluminum frame, a rear junction box, a back plate, a battery cell, a welding ribbon and a bus bar from a retired photovoltaic module to obtain a photovoltaic laminate, wherein the photovoltaic laminate comprises an EVA encapsulation film and a glass substrate;

[0063] (2) In an oxygen-containing atmosphere, the photovoltaic laminate is pyrolyzed by microwave heating, wherein the volume percentage of oxygen is 20 vol%, the microwave heating power is 700 W, the frequency is 2450 Hz, the photovoltaic laminate is heated to a temperature of 550° C. for 45 min, and a pyrolysis tail gas is obtained; the purity of carbon dioxide gas in the pyrolysis tail gas is 15 vol%; the pyrolysis tail gas is filtered, dried and compressed to reduce its volume to 20% of the original volume; wherein the filtration is carried out by a dust collector, and the drying is carried out by anhydrous calcium chloride;

[0064] (3) Carbon dioxide gas was passed into 300 mL of cyanobacteria (tested by Zhejiang University Laboratory) 60 In the culture medium of the high-efficiency carbon-fixing algae strain (after Co-γ-ray nuclear irradiation mutation and high-concentration CO2 gradient acclimation), the pH of the culture medium is monitored in real time using a pH detection device. When the pH is detected to be lower than 7.5, an alarm signal is generated and the introduction of carbon dioxide gas is stopped. When the pH is detected to be higher than 9.0, a pH regulator Tris-phosphate buffer is added to adjust the pH to a range of 7.5 to 9.0.

[0065] It should be noted that the formula of the Zarrouk medium for cyanobacteria in Example 1 is shown in Table 1.

[0066] Table 1

[0067]

[0068] Among them, A5 solution is trace elements, containing 2.86g / L H3BO3, 1.81g / L MnCl2·4H2O, 0.22g / L ZnSO4·7H2O, 0.08g / L CuSO4·5H2O and 0.01g / L MoO3.

[0069] Example 2

[0070] The difference from Example 1 is that the power of microwave heating is 400 W, so that the heating temperature of the photovoltaic laminate is 450°C.

[0071] Example 3

[0072] The difference from Example 1 is that the power of microwave heating is 1000W, so that the heating temperature of the photovoltaic laminate is 650°C.

[0073] Example 4

[0074] The difference from Example 1 is that the power of microwave heating is 200 W, so that the heating temperature of the photovoltaic laminate is 180°C.

[0075] Example 5

[0076] The difference from Example 1 is that the volume percentage of oxygen in the oxygen-containing atmosphere is 10 vol%.

[0077] Example 6

[0078] The difference from Example 1 is that the volume percentage of oxygen in the oxygen-containing atmosphere is 25 vol%.

[0079] Example 7

[0080] The difference from Example 1 is that the volume percentage of oxygen in the oxygen-containing atmosphere is 8 vol%.

[0081] Example 8

[0082] The difference from Example 1 is that step (3) includes: passing carbon dioxide gas into 300 mL of a culture medium containing Microsclerotium (freshwater algae species bank of the Chinese Academy of Sciences), using a pH detection device to monitor the pH of the culture medium in real time, generating an alarm signal when the pH is detected to be lower than 4, stopping the passing of carbon dioxide gas, and adding a pH regulator of 0.1 mol / L HCl or NaOH solution to adjust the pH to within the range of 4 to 8 when the pH is detected to be higher than 8.

[0083] It should be noted that the BG-11 culture medium of Microcoelenterate in Example 8 is shown in Table 2.

[0084] Table 2

[0085]

[0086] When preparing 1L of working solution, add 10mL of mother solution 1 to mother solution 4, 1mL of mother solution 5, and 1.5g of NaNO3 to 959mL of distilled water. After high-pressure steam sterilization, adjust the pH of the solution to 7.4-7.5 with Tris-HCl buffer.

[0087] Comparative Example 1

[0088] The difference from Example 1 is that step (1) and step (2) are omitted, that is, the retired photovoltaic modules are not recycled, and the purchased carbon dioxide gas is directly introduced into the culture medium. The CO2 gas ventilation rate is 25 mL / min, and the price of carbon dioxide gas is 500 yuan / 40L.

[0089] Comparative Example 2

[0090] The difference from Example 8 is that step (1) and step (2) are omitted, that is, the retired photovoltaic modules are not recycled, and the purchased carbon dioxide gas is directly introduced into the culture medium. The CO2 gas ventilation rate is 25 mL / min, and the price of carbon dioxide gas is 500 yuan / 40L.

[0091] All the above embodiments of the present application do not require additional purchase of CO2, and all the carbon dioxide gas in the pyrolysis tail gas is introduced into the culture medium. The cyanobacteria in Examples 1 to 7 and Comparative Example 1 and the microcoelenterate in Example 8 perform photosynthesis under the same lighting conditions to fix carbon, and the carbon fixation rate is summarized in Table 3.

[0092] Table 3

[0093] Carbon fixation rate (g / L / day) Example 1 1.19 Example 2 1.05 Example 3 1.26 Example 4 0.83 Example 5 1.02 Example 6 1.24 Example 7 1.01 Example 8 0.86 Comparative Example 1 1.16 Comparative Example 2 0.82

[0094] From the above description, it can be seen that the above embodiments of the present invention achieve the following technical effects:

[0095] The above method of the present application can organically combine the recycling of retired photovoltaic modules with biological carbon fixation, so that the packaging film can be recycled while reducing greenhouse gas emissions, which can improve the recycling rate of resources. By utilizing the biological carbon fixation effect of algae, the carbon dioxide gas generated by pyrolysis of the packaging film is effectively utilized, thereby reducing the gas source required for cultivating algae and reducing costs. In addition, the cultivated algae can be used to form biological crusts or algae crusts, which is of great significance for desert control.

[0096] It should be noted that the terms "first", "second", etc. in the specification and claims of the present application are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the terms used in this way can be interchangeable where appropriate, so that the embodiments of the present application described herein can be implemented in an order other than those described herein, for example.

[0097] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for recycling and treating retired photovoltaic modules and fixing carbon dioxide, characterized in that: The method comprises: Step S1, disassembling the retired photovoltaic modules to obtain photovoltaic laminates; the photovoltaic laminates include an encapsulation film and a glass substrate; Step S2, pyrolyzing the photovoltaic laminate to obtain pyrolysis tail gas; wherein the pyrolysis tail gas includes carbon dioxide gas and water; Step S3, culturing algae using the carbon dioxide gas as a carbon source to achieve carbon dioxide fixation.

2. The method for recycling and treating retired photovoltaic modules and fixing carbon dioxide according to claim 1, characterized in that: The step S1 comprises: disassembling the frame, junction box, back plate, battery cell, welding ribbon and bus bar in the retired photovoltaic module to obtain the photovoltaic laminate.

3. The method for recycling and treating retired photovoltaic modules and fixing carbon dioxide according to claim 1 or 2, characterized in that: The pyrolysis temperature is 450-650°C and the time is 30-60min; Preferably, the pyrolysis is carried out by microwave heating, tube furnace heating, laser heating or electric knife heating; Preferably, the power of the microwave heating is 400-1000 W, preferably 800-1000 W, and the frequency is 915 MHz or 2450 MHz, preferably 2450 MHz.

4. The method for recycling and treating retired photovoltaic modules and fixing carbon dioxide according to any one of claims 1 to 3, characterized in that: The pyrolysis is carried out in an oxygen-containing atmosphere, and the gas phase components in the pyrolysis tail gas include carbon dioxide gas; between step S2 and step S3, the step further includes: oxygen-enriched combustion of the pyrolysis tail gas, so that the gas phase components that are not fully oxidized are all converted into carbon dioxide gas to obtain combustion tail gas; Preferably, the method further comprises: compressing the combustion exhaust gas; Preferably, the volume percentage of oxygen in the oxygen-containing atmosphere is 10 to 25 vol%; Preferably, the volume of the compressed gas is 10-25% of the volume of the combustion exhaust gas.

5. The method for recycling and treating retired photovoltaic modules and fixing carbon dioxide according to any one of claims 1 to 3, characterized in that: The pyrolysis is carried out in air, and the gas phase components in the pyrolysis tail gas include carbon dioxide gas and hydrocarbons; between step S2 and step S3, the method further includes: treating the pyrolysis tail gas by catalytic oxidation to obtain a mixture of carbon dioxide gas and organic matter, wherein the organic matter is selected from one or more of C1-C5 aldehydes, C1-C5 carboxylic acids and C1-C5 alkanes; separating the carbon dioxide gas and the organic matter, acid-washing the organic matter to obtain an acid-washed product, or esterifying the organic matter to obtain an esterified product, and recovering and treating the acid-washed product and the esterified product; Preferably, the catalytic oxidation method is electrocatalytic oxidation or chemical catalytic oxidation, and the oxidant used in the catalytic oxidation method is selected from one or more of the group consisting of potassium permanganate, ozone and air oxidation.

6. The method for recycling and treating retired photovoltaic modules and fixing carbon dioxide according to claim 5, characterized in that: The organic matter is methane; the method further comprises: condensing and recovering the organic matter and using it for combustion to provide heat, and the generated waste heat is returned to step S2 and / or step S3; preferably, a heat exchanger is used to return the waste heat.

7. The method for recycling and treating retired photovoltaic modules and fixing carbon dioxide according to any one of claims 1 to 3, characterized in that: After filtering and drying the pyrolysis tail gas, step S3 is performed; Preferably, the filtration is performed using a dust collector or a membrane separation technique; Preferably, the drying process is carried out using a desiccant; preferably, the desiccant is selected from one or more of the group consisting of anhydrous calcium chloride, silica gel and activated carbon.

8. The method for recycling and treating retired photovoltaic modules and fixing carbon dioxide according to claim 7, characterized in that: The step S3 comprises: introducing the carbon dioxide gas into the culture medium of the algae to culture the algae; Preferably, the algae is selected from one or more of the group consisting of cyanobacteria, microscalycanthus, pseudocladonia, coccophorum, nostoc and anabaena; Preferably, the algae is cyanobacteria, the pH of the culture medium is 7.5-9.0, and the total inorganic carbon concentration is 100-550 mmol / L; or, the algae is Microscalyx, the pH of the culture medium is 4-8, and the total inorganic carbon concentration is 10-100 mmol / L; or, the algae is Pseudocranium, the pH of the culture medium is 5.5-7.5, and the total inorganic carbon concentration is 10-100 mmol / L; or, the algae is Chlorella, the pH of the culture medium is 5.5-7.5, and the total inorganic carbon concentration is 10-100 mmol / L; Preferably, the culturing is carried out in a photobioreactor.

9. The method for recycling and treating retired photovoltaic modules and fixing carbon dioxide according to claim 8, characterized in that: The step S3 further comprises: using a pH monitoring device and an inorganic carbon monitoring device to monitor the pH of the culture medium in real time, and generating an alarm signal when the pH is lower than the lower limit of the pH range required by the algae, and the intelligent control system closes the solenoid valve after receiving the alarm signal to stop the introduction of the carbon dioxide gas, and when the pH is higher than the upper limit of the pH range required by the algae, adding a pH regulator to adjust the pH to the required pH range; Preferably, the pH regulator is selected from an acidic compound, an alkaline compound or a neutral buffer; preferably, the acidic compound is selected from one or more of the group consisting of HCl, H2SO4 and citric acid, the alkaline compound is selected from NaOH and / or KOH, and the neutral buffer is selected from Tris-HCl buffer or Tris-phosphate buffer.

10. The method for recycling and treating retired photovoltaic modules and fixing carbon dioxide according to any one of claims 1 to 9, characterized in that: The packaging film is selected from PEVA film, POE film or EPE film.

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