Evaluation characterization method for determining decarburization rate of retired photovoltaic laminated piece glass

Abstract

The invention discloses an evaluation characterization method for determining the glass decarburization rate of a decommissioned photovoltaic laminate. The evaluation characterization method comprises the following steps: acquiring the carbon content CA of an adhesive film of the decommissioned photovoltaic laminate and the carbon content CC of decarburized photovoltaic glass; preparing a standard test block of the retired photovoltaic laminated piece, and obtaining the width W and the length L of the standard test block, the mass m0 of an adhesive film in the standard test block and the thickness D and the density rho g of photovoltaic glass in the standard test block; calculating the glass decarburization rate TC of the decommissioned photovoltaic laminated piece; according to the method, high-precision evaluation of the surface decarburization rate of the pyrolytic photovoltaic glass can be realized.

Description

Technical Field

[0001] This invention relates to the field of photovoltaic module recycling technology, and specifically to an evaluation and characterization method for determining the decarburization rate of glass in decommissioned photovoltaic laminates. Background Technology

[0002] With the depletion of global fossil fuel reserves and a shift in policy orientation, the development of clean and renewable energy is receiving increasing attention. Solar energy, due to its inexhaustible nature, is widely utilized, with the most common method being the conversion of solar energy into electricity through photovoltaic (PV) modules. my country is a major global producer and consumer of PV modules, and its PV industry has achieved remarkable success, with my country leading the world in newly installed PV capacity for many consecutive years.

[0003] The conversion efficiency of photovoltaic (PV) modules gradually declines with environmental factors and time, and the typical lifespan of PV modules is approximately 20-30 years. According to forecasts from the International Renewable Energy Agency (IRENA) and the International Energy Agency (IEA), global PV module scrapping will reach 8 million tons by 2030 and increase to 78 million tons by 2050. Simultaneously, with the steady growth of PV module installations and the development of solar PV manufacturing technology, the consumption rate of upstream raw materials is accelerating, raising concerns about the potential depletion of these key raw materials.

[0004] The traditional method of disposing of retired photovoltaic (PV) modules is direct burial. However, heavy metals such as lead, cadmium, and tin can seep into the soil, polluting groundwater. The polymer backsheets (such as PVDF and PET) and encapsulation materials (such as EVA, polyethylene-vinyl acetate copolymer) within the modules may slowly degrade in landfill environments, releasing fluorides or other potentially harmful chemicals. Furthermore, the direct burial of large numbers of PV modules occupies valuable land resources, and the landfill areas essentially lose their land function. Improper disposal methods, such as direct burial of retired PV modules, essentially shift the "cost" of short-term disposal convenience to the environment and society, causing long-term, hidden, and costly environmental pollution, resource waste, and health hazards. This not only violates the original intention of PV power generation as a clean energy source but also misses a crucial opportunity to develop a circular economy and achieve sustainable resource utilization.

[0005] like Figure 1 As shown in Table 1, crystalline silicon photovoltaic modules are laminated components, mainly composed of aluminum frames, photovoltaic glass, solar cells, encapsulant film, and backsheets. The mass and value proportions of each component in a crystalline silicon photovoltaic module are listed in Table 1. Photovoltaic glass is a crucial component of photovoltaic modules, and its performance directly affects the power generation efficiency and lifespan of the module. Photovoltaic glass accounts for over 70% of the mass of a photovoltaic module; therefore, the recycling of photovoltaic glass from retired photovoltaic laminates has significant environmental and economic implications.

[0006] Table 1

[0007] Component Name weight percentage (wt%) Value percentage Aluminum frame 14.50 31.80 Photovoltaic glass 70.00 5.78 silicon wafers 3.49 7.56 Back panel, silicone 1.81 0 Encapsulation film 7.50 0 Cables, junction boxes 0.92 0.72 Internal conductor aluminum, metallic silver, solder strip 1.78 54.14

[0008] Pyrolysis has become one of the most widely used and promising mainstream technologies in the resource recycling of retired photovoltaic modules due to its advantages such as high processing efficiency, significant material recovery rate, and controllable environmental impact. This process involves the thermal decomposition of organic components (such as EVA encapsulation film and backsheet polymers) in a high-temperature, oxygen-free or oxygen-limited environment, achieving effective dissociation of the solar cells (doped on silicon wafers), photovoltaic glass, and metal materials, laying the foundation for the subsequent classification and recycling of high-purity materials.

[0009] However, the pyrolysis process also faces some key technical obstacles, primarily manifested in the presence of residues on the glass surface after heat treatment. These residues mainly originate from solid carbon formed during the carbonization of the encapsulation material during pyrolysis, which firmly adheres to the uneven surface of the photovoltaic glass and is referred to as residual carbon. This residual carbon not only significantly reduces the glass's light transmittance and appearance quality but also hinders its direct reuse as a high-value building material. Furthermore, if it is remelted and recycled to produce photovoltaic glass, flat panels, bottles, glass wool, or other products, the residual carbon, due to its reducing properties, will cause the Fe in the glass to... 3+ Reduced to Fe 2+ Fe 2+ It will significantly change the optical properties of remelted glass, reduce the spectral transmittance and visible light transmittance of the glass, and color the glass as blue-green, affecting its appearance.

[0010] In the recycling process of decommissioned photovoltaic (PV) laminates, the separation of the laminates and the clean recovery of their components are key technical steps. Among these, the recycling and reuse of PV glass is crucial for improving the overall recycling rate and economic efficiency. However, after pyrolysis or physical methods to remove the encapsulant film, carbonaceous contaminants often remain on the surface of the decommissioned PV laminate glass, which are difficult to completely remove. These residual carbon particles severely affect the quality of the recycled glass, limiting its reuse value in high-end glass manufacturing and representing one of the main bottlenecks in achieving closed-loop, high-value recycling of PV glass. Therefore, accurately evaluating the effectiveness of decarburization treatment on the glass surface, using the "decarburization rate" as a key evaluation indicator, is essential. The closer this rate is to 100%, the more thorough and complete the decarburization treatment. This indicator is crucial for optimizing the decarburization process, assessing the impact on the quality of recycled glass, and guiding high-value utilization pathways.

[0011] Currently, there is a lack of unified, standardized, and operable testing and evaluation methods for assessing the decarburization effect on the surface of decommissioned photovoltaic glass. While some existing carbon content testing and evaluation methods can determine the total carbon content, there is still no consensus or standard on how to scientifically sample, separate, define, and calculate the "decarburization rate" of the glass surface, given that photovoltaic laminates are a special composite material. This leads to the following problems:

[0012] 1) Difficulty in process optimization: It is difficult to make objective and fair horizontal comparisons of the effects of different decarbonization processes, which hinders the research and development and promotion of efficient decarbonization technologies;

[0013] 2) Lack of quality control standards: Recycled glass manufacturers lack unified and reliable indicators to evaluate the cleanliness of raw glass, which affects the stability of recycled glass product quality.

[0014] 3) Market circulation barriers: The lack of a recognized method for testing and evaluating the decarbonization rate makes it difficult to establish a basis for quality certification and value assessment of recycled photovoltaic glass, which is not conducive to the standardization and large-scale development of the recycled photovoltaic glass market. Summary of the Invention

[0015] To address the shortcomings of existing technologies, this invention provides an evaluation and characterization method for determining the decarburization rate of decommissioned photovoltaic laminate glass.

[0016] This invention discloses an evaluation and characterization method for determining the decarburization rate of glass in decommissioned photovoltaic laminates, comprising:

[0017] Obtain the carbon content (C) of the encapsulant film for decommissioned photovoltaic laminates. A The carbon content C of photovoltaic glass after decarburization treatment C ;

[0018] Standard test blocks for decommissioned photovoltaic laminates were prepared, and the width W and length L of the standard test blocks, the mass m0 of the encapsulant film in the standard test blocks, and the thickness D and density ρ of the photovoltaic glass in the standard test blocks were obtained. g ;

[0019] Calculate the decarburization rate T of glass in decommissioned photovoltaic laminates C ;in,

[0020] As a further improvement of the present invention, the calculation of the decarburization rate T of the decommissioned photovoltaic laminate glass is described. C ,include:

[0021] Based on the width W and length L of the standard test block, calculate the planar area S0 of the photovoltaic glass sample before decarburization treatment; where S0 = WL;

[0022] Based on the mass m1 of the photovoltaic glass before decarburization treatment and the carbon content C of the photovoltaic glass after decarburization treatmentC Calculate the mass m2 of the photovoltaic glass after decarburization treatment; where m2 = m1(1-C C );

[0023] Based on the mass m2 of the decarburized photovoltaic glass, the thickness D and density ρ of the photovoltaic glass g Calculate the equivalent planar area S1 of the photovoltaic glass powder after decarburization treatment; where, In the formula, V is the equivalent volume of the photovoltaic glass powder after decarburization treatment;

[0024] The decarburization rate T of the decarburized photovoltaic laminate is calculated based on the difference between the carbon content before and after decarburization treatment and the ratio of the carbon content before decarburization treatment. C ;

[0025]

[0026] As a further improvement of the present invention, the carbon content (C) of the film is determined using a high-frequency carbon-sulfur analyzer. A The carbon content C of photovoltaic glass after decarburization treatment C .

[0027] As a further improvement of the present invention, the carbon content C of the adhesive film is... A The carbon content C of photovoltaic glass after decarburization treatment C The determination methods include:

[0028] Cut the decommissioned photovoltaic laminate to obtain test block A, and then dry test block A;

[0029] The dried sample block A was subjected to liquid nitrogen freezing separation to obtain the film sample;

[0030] The carbon content (C) of the film sample was determined using a high-frequency carbon-sulfur analyzer. A ;

[0031] Select decarburized photovoltaic glass particles or blocks, crush, screen and dry them to obtain decarburized photovoltaic glass powder;

[0032] The carbon content (C) of the decarburized photovoltaic glass powder was determined using a high-frequency carbon-sulfur analyzer. C ;

[0033] Among them, the carbon content C A and carbon content C C During the determination process, the output pressure of the oxygen cylinder used by the carbon-sulfur analyzer was 0.20MPa±0.02MPa, the oxygen pressure used by the carbon-sulfur analyzer was adjusted to 0.08MPa±0.01MPa, the flow rate was 1.5L / min±0.1L / min, and the flow rate was 3.0L / min during the purging after the test.

[0034] Carbon content C A During the testing process, the single injection volume of the film sample was 0.0100±0.0005g.

[0035] As a further improvement of the present invention, the mass m0 of the film is determined by the loss on ignition method.

[0036] As a further improvement of the present invention, the method for determining the mass m0 of the adhesive film includes:

[0037] Cut the decommissioned photovoltaic laminate to obtain test block B; and dry test block B.

[0038] Test block B was cut into standard test blocks of (40±1)mm×(40±1)mm and the standard test blocks were dried.

[0039] The standard test block was separated by liquid nitrogen freezing to separate its organic backsheet, resulting in a photovoltaic laminate with the backsheet removed.

[0040] The photovoltaic laminate with the backsheet removed is dried and placed in a chemical ceramic crucible that has been treated to constant weight. Its total mass is M1.

[0041] The crucible and the photovoltaic laminate after separating the back sheet were placed into a muffle furnace, heated to 650°C in an air atmosphere and held for 60 minutes. After cooling to room temperature, they were weighed again and recorded as M2.

[0042] Calculate the film mass m0 = M1 - M2.

[0043] As a further improvement of the present invention, a digital caliper is used to measure and record the length L and width W of the standard test block.

[0044] As a further improvement of the present invention, after the photovoltaic glass is placed in a muffle furnace for heat treatment, the thickness D of the photovoltaic glass is measured using a digital caliper.

[0045] As a further improvement of the present invention, the photovoltaic glass separated by heat treatment in the film quality determination step is cleaned with a brush to restore its surface to a clean and transparent state, and the density ρ of the photovoltaic glass is measured using the buoyancy method. g .

[0046] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0047] 1. This invention provides a test method for the decarbonization rate of photovoltaic glass for the retired photovoltaic glass recycling industry;

[0048] 2. This invention defines the quality standards for decommissioned photovoltaic glass;

[0049] 3. This invention drives closed-loop optimization of photovoltaic glass process, and provides feedback on the quality of recycled photovoltaic glass by measuring the decarbonization rate, thereby promoting photovoltaic glass recycling companies to improve their recycling processes.

[0050] 4. This invention promotes industrial resource recycling, indirectly improves the quality of recycled glass, and reduces resource consumption in the photovoltaic industry.

[0051] This invention fills the gap in the quality evaluation standards for photovoltaic glass recycling, improves the photovoltaic glass recycling system, connects the entire chain of "testing-grading-process optimization-resource conservation", and promotes the photovoltaic industry towards a circular economy and sustainable development. Attached Figure Description

[0052] Figure 1 This is a schematic diagram of the structure of an existing crystalline silicon photovoltaic module;

[0053] Figure 2 This is a flowchart of the evaluation and characterization method for determining the decarburization rate of glass in decommissioned photovoltaic laminates disclosed in this invention;

[0054] Figure 3 and Figure 4 The effect of different burn-off conditions on the calculation of decarburization rate disclosed in this invention;

[0055] Figure 5 and Figure 6 This invention discloses the effect of different single injection volumes on the calculation of decarbonization rate.

[0056] Figure 7 and Figure 8 This invention discloses the effect of different laminate dimensions on the calculation of decarburization rate. Detailed Implementation

[0057] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0058] The present invention will now be described in further detail with reference to the accompanying drawings:

[0059] This invention provides a method for evaluating and characterizing the decarburization rate of decommissioned photovoltaic glass recycled by pyrolysis. Based on the research results and practical experience of the National Key Research and Development Program "Decarburization, Impurity Removal, Recycling, and Remelting Technology of Waste Glass," this invention solves the following key problems:

[0060] 1) Core concepts were clarified: The concepts and physical meanings of "decarbonization treatment" and "decarbonization rate" for decommissioned photovoltaic laminates were clearly defined;

[0061] 2) The test method is specified: The specific steps, instrument requirements, calculation formulas and report content for determining the decarbonization rate are specified in detail based on the principle of high-frequency infrared carbon and sulfur analysis, combined with specific sample preparation, key parameter measurement and calculation model.

[0062] 3) Provides operation guidelines: Provides a complete, operable, and repeatable testing process for recycling companies, recycled glass plants, testing institutions, and R&D units.

[0063] like Figure 2 As shown, this invention provides an evaluation and characterization method for determining the decarburization rate of decomposition photovoltaic laminate glass. It achieves high-precision evaluation of the decarburization rate on the surface of pyrolytic photovoltaic glass through a combination of techniques including liquid nitrogen freezing separation, burn-off sampling, and carbon-sulfur analysis. Specifically, it includes:

[0064] Step 1: Prepare a 40mm×40mm standard test block, an encapsulated film sample, a laminate sample with the backing plate removed, and a photovoltaic glass powder sample.

[0065] Step 2: Use a high-frequency carbon-sulfur analyzer to determine the carbon content (C) of the encapsulant film samples from decommissioned photovoltaic laminates. A The carbon content C of photovoltaic glass after decarburization treatment C ;

[0066] Step 3: Use a digital caliper to measure and record the length L and width W of the standard test block; use a digital caliper to measure the thickness D of the photovoltaic glass; use the burn-off method to determine the mass m0 of the encapsulant film; and use the buoyancy method to determine the density ρ of the photovoltaic glass. g ;

[0067] Step 4: Substitute the measured parameters into the decarburization rate calculation formula to calculate the decarburization rate T of the decommissioned photovoltaic laminate glass. C ;in,

[0068] Calculate the decarburization rate T of glass in decommissioned photovoltaic laminates C Specifically, it includes:

[0069] Based on the width W and length L of the standard test block, calculate the planar area S0 of the photovoltaic glass sample before decarburization treatment; where S0 = WL;

[0070] Based on the mass m1 of the photovoltaic glass before decarburization treatment and the carbon content C of the photovoltaic glass after decarburization treatment C Calculate the mass m2 of the photovoltaic glass after decarburization treatment; where m2 = m1(1-C C );

[0071] Based on the mass m2 of the decarburized photovoltaic glass, the thickness D and density ρ of the photovoltaic glass g Calculate the equivalent planar area S1 of the photovoltaic glass powder after decarburization treatment; where,

[0072] The decarburization rate T of the decarburized photovoltaic laminate is calculated based on the difference between the carbon content before and after decarburization treatment and the ratio of the carbon content before decarburization treatment. C ;

[0073]

[0074] In the formula:

[0075] T C —Decarbonization rate, expressed as a percentage (%);

[0076] m0 — Mass of the film, in grams (g);

[0077] m1 — Mass of photovoltaic glass before decarburization treatment, in grams (g);

[0078] m2 — Mass of photovoltaic glass after decarburization treatment, in grams (g);

[0079] C A —The carbon content of the film, expressed as a percentage by mass (wt%);

[0080] C C —The carbon content of photovoltaic glass powder after decarburization treatment, expressed as a percentage by mass (wt%);

[0081] S0 – The planar area of ​​the photovoltaic glass sample before decarburization treatment, in square centimeters (cm²). 2 );

[0082] S1 – The equivalent planar area of ​​the photovoltaic glass powder after decarburization treatment, in square centimeters (cm²). 2 );

[0083] W—Width of the standard test block, in centimeters (cm);

[0084] L—The length of the standard test block, in centimeters (cm);

[0085] V – The converted volume of photovoltaic glass powder after decarburization treatment, in cubic centimeters (cm³). 3 );

[0086] D – The thickness of the photovoltaic glass, in centimeters (cm);

[0087] ρ g—The density of photovoltaic glass is expressed in grams per cubic centimeter (g / cm³). 3 ).

[0088] Furthermore, the carbon content C of the film A The carbon content C of photovoltaic glass after decarburization treatment C The determination methods include:

[0089] Cut the decommissioned photovoltaic laminate to obtain test block A, and then dry test block A;

[0090] The dried sample block A was subjected to liquid nitrogen freezing separation to obtain the film sample;

[0091] The carbon content (C) of the film sample was determined using a high-frequency carbon-sulfur analyzer. A ;

[0092] Select decarburized photovoltaic glass particles or blocks, crush, screen and dry them to obtain decarburized photovoltaic glass powder;

[0093] The carbon content (C) of the decarburized photovoltaic glass powder was determined using a high-frequency carbon-sulfur analyzer. C ;

[0094] Among them, the carbon content C A and carbon content C C During the determination process, the output pressure of the oxygen cylinder used by the carbon-sulfur analyzer was 0.20MPa±0.02MPa, the oxygen pressure used by the carbon-sulfur analyzer was adjusted to 0.08MPa±0.01MPa, the flow rate was 1.5L / min±0.1L / min, and the flow rate was 3.0L / min during the purging after the test.

[0095] Carbon content C A During the testing process, the single injection volume of the film sample was 0.0100±0.0005g.

[0096] Furthermore, the method for determining the mass m0 of the film includes:

[0097] Cut the decommissioned photovoltaic laminate to obtain test block B; and dry test block B.

[0098] Test block B was cut into standard test blocks of (40±1)mm×(40±1)mm and the standard test blocks were dried.

[0099] The standard test block was separated by liquid nitrogen freezing to separate its organic backsheet, resulting in a photovoltaic laminate with the backsheet removed.

[0100] The photovoltaic laminate with the backsheet removed is dried and placed in a chemical ceramic crucible that has been treated to constant weight. Its total mass is M1.

[0101] The crucible and the photovoltaic laminate after separating the back sheet were placed into a muffle furnace, heated to 650°C in an air atmosphere and held for 60 minutes. After cooling to room temperature, they were weighed again and recorded as M2.

[0102] Calculate the film mass m0 = M1 - M2.

[0103] To better present the main idea and effects of the invention, this invention has selected the most representative embodiments and comparative examples (see Tables 1 to 5) to verify the burn-off conditions and C obtained in the test process. A The sample injection amount and flux addition amount, as well as the applicability of test blocks of different sizes, are only typical numerical parameters used in the examples. They are not displayed and expanded indefinitely. The examples are sufficient to fully reflect and represent the innovation of the present invention.

[0104] The specific implementation should use retired photovoltaic modules as the test object, and the pretreatment and related parameter measurement of the embodiment should be carried out in accordance with the following provisions.

[0105] Example 1: Decarbonization rate T C Determination methods

[0106] The steps and requirements for preparing standard test blocks of decommissioned photovoltaic laminates are as follows: Randomly select a decommissioned photovoltaic laminate that is either entirely intact or partially intact, and cut two test blocks using a handheld cutter; the size of the test blocks is (100±10)mm×(100±10)mm; after cleaning the test blocks with pure water, place them in an 80℃ oven and dry for 60 minutes before taking them out for sample preparation:

[0107] 1) Film sample (hereinafter referred to as sample A).

[0108] Sample A is used for the determination of carbon content in the adhesive film. Its preparation steps and requirements are as follows:

[0109] Select a 100mm×100mm square test block A and place it in a 500mL stainless steel container filled with liquid nitrogen. The square test block should be completely immersed in the liquid nitrogen and the freezing time should not be less than 180s. Use stainless steel tweezers to remove the square test block A and manually separate it to obtain photovoltaic glass, backsheet, cell and encapsulant film. Place the encapsulant film in an 80℃ oven and dry it for 60min. Then take it out for use and mark it as sample A.

[0110] 2) Laminated component specimen (hereinafter referred to as specimen B).

[0111] Sample B is used for film quality determination, and its preparation steps and requirements are as follows:

[0112] Select a 100mm×100mm square test block B, and cut a (40±1)mm×(40±1)mm square sample using a benchtop cutter; clean it with pure water, put it in an 80℃ oven, dry it for 60 minutes, and then take it out for use.

[0113] 3) Photovoltaic glass powder (referred to as sample C).

[0114] Sample C is used to determine the carbon content of photovoltaic glass after decarburization treatment. The sample preparation steps and requirements are as follows:

[0115] Randomly select 4g to 5g of decarburized photovoltaic glass particles or blocks; crush and grind the photovoltaic glass particles or blocks using an agate mortar with a diameter of 100mm to 150mm; repeatedly sieve the ground powder using a standard sieve to ensure that all of it passes through the standard sieve; collect the powder that passes through the sieve, put it in an 80℃ oven, dry it for 60 minutes, and then take it out for use.

[0116] The steps for determining the quality of the adhesive film are as follows:

[0117] a) Use a digital caliper to measure and record the length L and width W of sample B (in millimeters, accurate to two decimal places);

[0118] b) Place sample B into a 500 mL stainless steel container filled with liquid nitrogen, and immerse it completely in the liquid nitrogen for 20 to 30 seconds.

[0119] c) Use stainless steel tweezers to remove sample B and separate its organic backsheet to obtain a photovoltaic laminate with the backsheet removed;

[0120] d) Place the photovoltaic laminate with the backsheet removed into an 80°C oven and dry for 60 minutes. Remove it and cool it to room temperature.

[0121] e) Place the dried backplate-removed laminate into a 100mL chemical ceramic crucible that has been constant-weighted (at 1000℃ for 60min), weigh and record the total mass M1 of the two (the crucible and the sample B after backplate separation) using an electronic balance.

[0122] f) Place both (the crucible and the sample B after separation of the back plate) into a muffle furnace, heat to 650°C in air atmosphere and hold for 60 min;

[0123] g) After cooling to room temperature, weigh again and record the weight as M2;

[0124] h) Use a digital caliper to measure the thickness D of the photovoltaic glass (in millimeters, rounded to two decimal places).

[0125] i) The mass of the adhesive film is M1-M2, denoted as m0.

[0126] The steps for measuring the density of photovoltaic glass are as follows:

[0127] The photovoltaic glass separated by heat treatment in the film quality determination step is cleaned with a brush to restore its clean and transparent state. The density ρ of the photovoltaic glass is then measured according to the method specified in GB / T 5432. g .

[0128] The steps for determining carbon content are as follows:

[0129] a) Turn on the power to the infrared carbon-sulfur analyzer and the electronic balance;

[0130] b) Start the computer and open the measurement software;

[0131] c) Turn on the two-stage pressure regulator of the oxygen cylinder and adjust the oxygen output pressure (stage 1) of the cylinder to (0.20±0.02) MPa; adjust the oxygen pressure (stage 2) input to the infrared carbon-sulfur analyzer to (0.08±0.01) MPa and the flow rate to (1.5±0.1) L / min; the flow rate during purging after each test is 3.0 L / min;

[0132] d) The infrared carbon-sulfur analyzer was calibrated using the GSB 06-3345 standard sample;

[0133] e) Weigh (0.0100±0.0005)g of sample A and (1.50±0.05)g of pure tungsten flux for carbon and sulfur analysis in sequence, and place them in the analysis crucible that has been heated to constant weight (at 1200℃ for 60min).

[0134] f) Place the analytical crucible containing the sample and flux into the heating furnace of the infrared carbon-sulfur analyzer for testing. Test sample A three times, and take the average carbon content result, retaining five decimal places, denoted as C. A .

[0135] g) The infrared carbon-sulfur analyzer was calibrated using the YSBC 37381-16 standard sample;

[0136] h) Weigh 0.1g to 0.2g of sample C and 1.50g of pure tungsten flux for carbon and sulfur analysis, and place them sequentially into an analytical crucible that has been heated to constant weight (held at 1200℃ for 60min). Calculate the average carbon content of sample C according to f), retaining five decimal places, and record it as C. C ;

[0137] i) After the test is completed, shut down the test software, computer, carbon-sulfur analyzer, oxygen cylinder valve, and electronic balance in sequence.

[0138] To compare the advantages and effects of the present invention, the present invention sets up one embodiment (Table 1) and three comparative examples, namely Comparative Example 1 to Comparative Example 3 (see Tables 2 to 4), according to the above-mentioned decarbonization rate test method.

[0139] The conditions for this example were set as follows: laminate size 40mm*40mm, burn-off condition 650℃ for 60min, and single injection volume 0.01. The decarburization process of the decarburized glass used in this example was: 500℃ for 60min under a nitrogen atmosphere. Three comparative examples were set up to investigate the effects of different burn-off conditions, different single injection volumes, and different laminate sizes on the calculation of the decarburization rate. In Comparative Example 1, as the burn-off temperature increased and the holding time lengthened, the obtained m0 value gradually increased and tended towards the actual value. Through a large number of burn-off experiments, the burn-off conditions with the most thorough burn-off and the value closest to the actual film quality were determined, see [link to example]. Figure 3 , Figure 4 When the temperature was held at 650℃ for 60 minutes, the burn-off rate reached its maximum value. Comparative Example 1 investigated the effect of different burn-off conditions on the calculated decarburization rate; the calculated decarburization rates under different burn-off conditions differed by more than 1000 ppm. Comparative Example 2 compared the effect of different single injection volumes on the decarburization rate. Because photovoltaic films have a high carbon content, a higher single injection volume can lead to tailing during carbon analysis. Figure 5 , Figure 6 This means the detected carbon content will be lower than the actual value. The effect of the unit injection volume on the decarbonization rate is about 100 ppm. Photovoltaic glass sample C C Because of its low carbon content, there is no need to verify the presence of tailing. With a fixed oxygen blowing rate in the furnace tube and a fixed analysis time, a small amount of pure tungsten flux results in incomplete combustion, a slower carbide release rate, and thus peak tailing. Conversely, an excessive amount of pure tungsten flux increases the oxygen demand for flux melting, leading to insufficient oxygen for the sample, incomplete combustion, a slower carbide release rate, and tailing. In practice, the smaller the sample weight, the more difficult and harder to control the weighing process. Based on experimental observations, adding 1.5g of flux resulted in only a small amount of tailing at approximately 0.013g of sample, indicating that the flux addition was moderate and the sample weight was appropriate. In Comparative Example 3, by comparing the effects of different sized laminate specimens on the decarburization rate calculation, it was found that the error range of the decarburization rate between 30mm*30mm and 70mm*70mm sizes was less than 100ppm, indicating a relatively small impact. Therefore, it is only necessary to investigate the influence of the photovoltaic laminate size effect on the experimental procedure. The larger the size of the photovoltaic laminate, the lower the heat transfer efficiency. Under the same temperature conditions, the burn-off rate of smaller photovoltaic laminates is always higher than that of larger photovoltaic laminates. For example, the burn-off rate of a 30mm*30mm photovoltaic laminate at 500℃ for 30 minutes can reach over 0.099%. Figure 7 , Figure 8 However, small sizes are not easy to precisely control during cutting, and are more prone to errors. 40mm*40mm is sufficient to meet the requirements of the decarburization rate test.

[0140] Table 1 Examples

[0141]

[0142]

[0143] The temperatures and holding times for determining the film quality were set to 400℃, 450℃, 500℃, 550℃, 600℃, 650℃, and 650℃, respectively; the holding times were 15min, 30min, 45min, 60min, and 75min, respectively; and the other test conditions and procedures were exactly the same as in the example.

[0144] Table 2 Comparative Example 1

[0145]

[0146]

[0147] When using a high-frequency carbon-sulfur analyzer to detect the carbon content of the film, different single injection volumes were used, while the remaining test steps and conditions were the same as in the examples.

[0148] Table 3 Comparative Example 2

[0149]

[0150]

[0151]

[0152]

[0153]

[0154] Test blocks of 30mm×30mm, 40mm×40mm, 50mm×50mm, 60mm×60mm, and 70mm×70mm were prepared respectively, and the decarbonization rate was determined according to the steps and conditions of the example.

[0155] Table 4 Comparative Example 3

[0156]

[0157]

[0158] The implementation of this invention has the following important significance:

[0159] 1) Supporting technological innovation: Providing a unified and scientific evaluation standard for assessing and optimizing various decarbonization technologies for retired photovoltaic glass, and accelerating the research and application of efficient, environmentally friendly, and low-cost decarbonization and impurity removal technologies;

[0160] 2) Ensure the quality of recycled glass: Provide core quality testing methods for recycled glass manufacturers to ensure the cleanliness of recycled glass raw materials, improve the quality and added value of recycled glass products, and promote their application in fields such as construction, daily use, and even photovoltaic backsheet glass;

[0161] 3) Standardize the recycling market: Establish a quality evaluation basis for recycled materials from retired photovoltaic glass to promote the standardized trading and market circulation of recycled glass.

[0162] 4) Improved standard system, filling the gap in the evaluation method standard for glass surface cleanliness in the field of retired photovoltaic module recycling and processing, and is an important part of building and improving the standard system for photovoltaic module recycling and reuse;

[0163] 5) Facilitating Low-Carbon Circulation: By promoting the efficient and high-value recycling and reuse of photovoltaic glass, it significantly reduces raw material mining, energy consumption, and waste landfill, thereby reducing carbon emissions and providing technical support for the green, low-carbon, and circular development of the photovoltaic industry and the realization of the national "dual-carbon" strategic goals.

[0164] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for evaluating and characterizing the decarburization rate of glass in decommissioned photovoltaic laminates, characterized in that, include: Obtain the carbon content (C) of the encapsulant film from decommissioned photovoltaic laminates. A The carbon content C of photovoltaic glass after decarburization treatment C ; Standard test blocks for decommissioned photovoltaic laminates were prepared, and the width W and length L of the standard test blocks, the mass m0 of the encapsulant film in the standard test blocks, and the thickness D and density ρ of the photovoltaic glass in the standard test blocks were obtained. g ; Calculate the decarburization rate T of glass in decommissioned photovoltaic laminates C ;in, 2. The evaluation and characterization method for determining the decarburization rate of decommissioned photovoltaic laminate glass as described in claim 1, characterized in that, The calculation of the decarburization rate T of decommissioned photovoltaic laminate glass. C ,include: Based on the width W and length L of the standard test block, calculate the planar area S0 of the photovoltaic glass sample before decarburization treatment; where S0 = WL; Based on the mass m1 of the photovoltaic glass before decarburization treatment and the carbon content C of the photovoltaic glass after decarburization treatment C Calculate the mass m2 of the photovoltaic glass after decarburization treatment; where m2 = m1(1-C C ); Based on the mass m2 of the decarburized photovoltaic glass, the thickness D and density ρ of the photovoltaic glass g Calculate the equivalent planar area S1 of the photovoltaic glass powder after decarburization treatment; where, In the formula, V is the equivalent volume of the photovoltaic glass powder after decarburization treatment; The decarburization rate T of the decarburized photovoltaic laminate is calculated based on the difference between the carbon content before and after decarburization treatment and the ratio of the carbon content before decarburization treatment. C ; 3. The evaluation and characterization method for determining the decarburization rate of decommissioned photovoltaic laminate glass as described in claim 1 or 2, characterized in that, The carbon content (C) of the film was determined using a high-frequency carbon-sulfur analyzer. A The carbon content C of photovoltaic glass after decarburization treatment C .

4. The evaluation and characterization method for determining the decarburization rate of decommissioned photovoltaic laminate glass as described in claim 3, characterized in that, Carbon content C of the film A The carbon content C of photovoltaic glass after decarburization treatment C The determination methods include: Cut the decommissioned photovoltaic laminate to obtain test block A, and then dry test block A; The dried sample block A was subjected to liquid nitrogen freezing separation to obtain the film sample; The carbon content (C) of the film sample was determined using a high-frequency carbon-sulfur analyzer. A ; Select decarburized photovoltaic glass particles or blocks, crush, screen and dry them to obtain decarburized photovoltaic glass powder; The carbon content (C) of the decarburized photovoltaic glass powder was determined using a high-frequency carbon-sulfur analyzer. C ; Among them, the carbon content C A and carbon content C C During the determination process, the output pressure of the oxygen cylinder used by the carbon-sulfur analyzer was 0.20MPa±0.02MPa, the oxygen pressure used by the carbon-sulfur analyzer was adjusted to 0.08MPa±0.01MPa, the flow rate was 1.5L / min±0.1L / min, and the flow rate was 3.0L / min during the purging after the test. Carbon content C A During the testing process, the single injection volume of the film sample was 0.0100±0.0005g.

5. The evaluation and characterization method for determining the decarburization rate of decommissioned photovoltaic laminate glass as described in claim 1 or 2, characterized in that, The mass m0 of the film was determined using the burn-off method.

6. The evaluation and characterization method for determining the decarburization rate of decommissioned photovoltaic laminate glass as described in claim 5, characterized in that, Methods for determining the mass m0 of the adhesive film include: Cut the decommissioned photovoltaic laminate to obtain test block B; and dry test block B. Test block B was cut into standard test blocks of (40±1)mm×(40±1)mm and the standard test blocks were dried. The standard test block was separated by liquid nitrogen freezing to separate its organic backsheet, resulting in a photovoltaic laminate with the backsheet removed. The photovoltaic laminate with the backsheet removed is dried and placed in a chemical ceramic crucible that has been treated to constant weight. Its total mass is M1. The crucible and the photovoltaic laminate after separating the back sheet were placed into a muffle furnace, heated to 650°C in an air atmosphere and held for 60 minutes. After cooling to room temperature, they were weighed again and recorded as M2. Calculate the film mass m0 = M1 - M2.

7. The evaluation and characterization method for determining the decarburization rate of decommissioned photovoltaic laminate glass as described in claim 6, characterized in that, Use a digital caliper to measure and record the length L and width W of the standard test block.

8. The evaluation and characterization method for determining the decarburization rate of decommissioned photovoltaic laminate glass as described in claim 6, characterized in that, After the photovoltaic glass is placed in a muffle furnace for heating treatment, the thickness D of the photovoltaic glass is measured using a digital caliper.

9. The evaluation and characterization method for determining the decarburization rate of decommissioned photovoltaic laminate glass as described in claim 6, characterized in that, The photovoltaic glass separated by heat treatment in the film quality determination step was cleaned with a brush to restore its surface to a clean and transparent state. The density ρ of the photovoltaic glass was then measured using the buoyancy method. g .

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