Laser pyrolysis method and device for single-glass photovoltaic module

Abstract

The invention relates to a laser pyrolysis method and equipment for a single-glass photovoltaic module. After a single-glass waste photovoltaic module is preheated and a back plate is torn off, a back-plate-free module is pyrolyzed in a semi-closed environment by using laser, particularly long-wave laser, so that the pyrolysis of a photovoltaic adhesive film can be effectively completed, the pyrolysis process can be carried out in a nitrogen environment, and harmful gas generated in the pyrolysis process is collected through an exhaust pipeline and further treated. Besides, in the laser pyrolysis process, the pyrolysis furnace does not need to be heated to maintain the furnace temperature, energy emitted by long-wave laser is directly transmitted to the backboard-free assembly, and the pyrolysis reaction occurs in the assembly, so that compared with traditional pyrolysis, the reaction temperature is reduced, the reaction time is shortened, the separation efficiency of the photovoltaic assembly is improved, and environmental pollution is reduced; the waste photovoltaic module can be efficiently treated in an environment-friendly mode, and effective recycling of materials is achieved.

Description

Technical Field

[0001] The present invention relates to photovoltaic module recycling technology in the field of solar energy, and in particular to a laser pyrolysis method and equipment for a single-glass photovoltaic module. Background Art

[0002] As global environmental problems become increasingly severe and the energy crisis intensifies, photovoltaic power generation, as a clean and renewable energy source, has seen rapid growth in installed capacity in recent years. However, the large-scale application of photovoltaic power generation has inevitably led to the issue of recycling discarded photovoltaic modules.

[0003] Photovoltaic module recycling technology currently has some invention patents. CN114769272A discloses a pyrolysis recovery device for waste photovoltaic modules, which can effectively separate the tempered glass plates and crystalline silicon cells of waste photovoltaic modules. The device includes a first conveying mechanism, a pyrolysis chamber and a second conveying mechanism, and the pyrolysis chamber includes a pyrolysis chamber chain plate and a number of ceramic heat storage heating tubes. The above device is used to treat waste photovoltaic modules. The photovoltaic modules are sent into the pyrolysis chamber by the first conveying mechanism for pyrolysis. The separated battery fragments are discharged from the battery cell residue outlet, and the complete glass plate is cooled in the second conveying mechanism and discharged. The pyrolysis temperature of the above pyrolysis method is between 350℃ and 800℃, and the pyrolysis time is 20 minutes to 120 minutes.

[0004] CN118218368A discloses a photovoltaic module recycling process, which includes a back layer removal step, a front layer removal step, and a cell recycling step. On the one hand, the process is based on multiple partitions and complementarity to cover the entire back side, and under the cooperation of a pressure roller set and grinding or milling, based on the different forces that hinder the deflection of the photovoltaic module and the torque formed by each level of partition, the photovoltaic module is gradually removed from the back layer when the sum of the rotational torque around the vertical direction is zero. Not only is the removal efficiency high, the back layer residue rate is low, but also the front layer damage rate is low. However, the mechanical crushing method used in this technology requires complex mechanical processing of the photovoltaic module, which is easy to damage the valuable materials in the module, resulting in a problem of reduced recovery rate. The existing technology mainly has the following disadvantages:

[0005] 1. Traditional mechanical crushing methods require complex mechanical processing of photovoltaic modules, which can easily damage valuable materials in the modules, resulting in reduced recycling rates;

[0006] 2. Chemical treatment methods require the use of a large amount of chemical reagents, which not only increases the treatment cost, but also may bring the risk of environmental pollution;

[0007] 3. The existing pyrolysis technology has a high processing temperature and a long reaction time, which reduces the separation efficiency of photovoltaic modules.

[0008] Therefore, finding an efficient and environmentally friendly waste photovoltaic module processing equipment has become an urgent problem to be solved in the industry. Summary of the invention

[0009] In view of the problems existing in the prior art, the present invention provides a laser pyrolysis method for a single-glass photovoltaic module, comprising the following steps:

[0010] a. Preheat the single-glass waste photovoltaic modules to 100℃~200℃;

[0011] b. Remove the backboard to obtain a backboard-free module;

[0012] c. Place the backboard-free assembly with the glass surface facing the conveyor belt 30 and send it into the tunnel pyrolysis furnace 20;

[0013] d. closing the furnace door 70 of the component inlet 610 and the residue outlet 620;

[0014] e. Turn on the laser transmitter 80 to scan the components without backboard and pyrolyze the adhesive film;

[0015] f. Extract and condense pyrolysis gas;

[0016] g. Open the furnace door 70 at the residue outlet 620, and send the pyrolysis residue out of the tunnel pyrolysis furnace 20 through the conveyor belt 30 to the next process.

[0017] Further, step d also includes: after closing the furnace door 70 of the component inlet 610 and the residue outlet 620, nitrogen is filled into the tunnel pyrolysis furnace 20 to reduce the generation of oxides during the pyrolysis process;

[0018] Furthermore, step e also includes: adjusting the scanning angle and scanning speed of the laser emitter (80) according to the size of the single-glass photovoltaic module.

[0019] Furthermore, in step e, the laser emitter (80) emits long-wave laser light with a wavelength of 900 nm to 1200 nm.

[0020] The present invention also provides a single-glass photovoltaic module laser pyrolysis device 100, comprising a tunnel pyrolysis furnace (20) and a conveyor belt (30), the tunnel pyrolysis furnace comprising an air intake pipeline 40, an exhaust pipeline 50 and a shell 60, the shell having a module inlet 610 and a residue outlet 620, the module inlet 610 and the residue outlet 620 being provided with furnace doors 70 respectively, the conveyor belt 30 passing through the module inlet 610 and the residue outlet 620, and a laser emitter 80 being arranged inside the shell 60 for emitting laser to pyrolyze the adhesive film.

[0021] Furthermore, the air inlet pipeline 40 is connected to an inert gas source for filling the tunnel pyrolysis furnace 20 with inert gas during the pyrolysis process.

[0022] Further, the laser emitter 80 is a single long-wave laser emitter.

[0023] Furthermore, the laser emitters 80 are arranged in an array, covering the width direction of the conveyor belt 30 .

[0024] Furthermore, the conveyor belt 30 is a continuous belt or a discontinuous group.

[0025] Compared with the prior art, the present invention provides a method and device for laser pyrolysis of a single-glass photovoltaic module, which has the following beneficial effects:

[0026] 1. Use a laser transmitter to emit laser to pyrolyze the backboard-free components. The pyrolysis process is carried out in an inert gas environment, which reduces the generation of oxides during the pyrolysis process and helps to promote the discharge of harmful gases through the exhaust pipe;

[0027] 2. During the pyrolysis process, the pyrolysis furnace does not need to be heated to maintain the furnace temperature. The energy emitted by the laser is directly transmitted to the backboard-free module, and the pyrolysis reaction occurs inside the module. Compared with traditional pyrolysis, the reaction temperature is reduced and the reaction time is shortened, thereby improving the separation efficiency of the photovoltaic module;

[0028] 3. The equipment has a compact structure and is easy to operate. It can achieve efficient and environmentally friendly treatment of waste photovoltaic modules and effective recycling of materials, and has good application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 This is a schematic diagram of the component recovery equipment in Example 1 of the present invention.

[0030] Figure 2 This is a schematic diagram of the component recovery equipment in Example 2 of the present invention.

[0031] 100——Laser pyrolysis equipment for single-glass photovoltaic modules;

[0032] 20 – tunnel pyrolysis furnace;

[0033] 30 – conveyor belt;

[0034] 40 – air intake pipe;

[0035] 50 – Exhaust pipe;

[0036] 60 - housing,

[0037] 610 – Component imports;

[0038] 620 – Residue export;

[0039] 70 – furnace door;

[0040] 80 – laser transmitter; DETAILED DESCRIPTION

[0041] The present invention is further described in detail below with reference to the accompanying drawings and specific implementation modes.

[0042] A single-glass photovoltaic module laser pyrolysis device is applied to a single-glass photovoltaic module laser pyrolysis method, comprising a tunnel pyrolysis furnace and a conveyor belt. The tunnel pyrolysis furnace comprises an air intake pipeline, an exhaust pipeline and a shell. The shell has a module inlet and a residue outlet. The module inlet and the residue outlet are respectively provided with furnace doors. The conveyor belt runs through the module inlet and the residue outlet. A laser emitter is arranged inside the shell for emitting laser to pyrolyze a photovoltaic film.

[0043] Specifically, the tunnel pyrolysis furnace is a rectangular structure with a length of 3 meters, a width of 2 meters and a height of 1 meter. The shell is made of high-temperature resistant alloy steel material, and the inner wall is provided with a heat insulation layer. The thickness of the heat insulation layer is 10 cm and it is made of ceramic fiber material, which can effectively isolate heat loss and keep the temperature in the furnace stable. The component inlet is located at one end of the tunnel pyrolysis furnace, and the residue outlet is located at the other end of the tunnel pyrolysis furnace. The two are respectively arranged on the front and back sides of the tunnel pyrolysis furnace.

[0044] The furnace doors at the module inlet and residue outlet adopt an electric lifting door structure, which is made of high-temperature resistant alloy material. The door frame is filled with heat-insulating material to ensure airtightness when closed. The opening and closing of the furnace door is controlled by an electric control system, which can be operated automatically. The size of the furnace door matches the size of the module inlet and residue outlet, with a width of 1.4 meters and a height of 0.4 meters, which can meet the entry and exit requirements of photovoltaic modules.

[0045] The conveyor belt runs through the module inlet and the residue outlet. It adopts a high-temperature resistant metal mesh belt structure with a width of 1.2 meters, which can carry single-glass photovoltaic modules of various specifications. The conveyor belt is driven by a variable frequency motor, and the speed can be adjusted within the range of 0.1-10 meters / minute to meet the pyrolysis requirements of photovoltaic modules of different sizes. The surface treatment of the conveyor belt is an anti-stick coating to prevent the adhesion of sticky substances generated during the pyrolysis process.

[0046] The air inlet pipe is connected to the side wall of the tunnel pyrolysis furnace. The pipe diameter is 50 mm and made of stainless steel. It is connected to a gas flow control valve to control the amount of inert gas entering. A gas distribution system is set in the air inlet pipe to ensure that the inert gas can be evenly distributed inside the furnace cavity.

[0047] The exhaust pipe is set at the top of the tunnel pyrolysis furnace. The pipe diameter is 80 mm and is made of high-temperature resistant alloy material. The exhaust pipe is connected to an exhaust fan and a condensing device. The power of the exhaust fan is 2 kilowatts and the maximum exhaust volume is 500 cubic meters per hour. The condensing device includes a condenser and a collection container. The condenser adopts a spiral tube structure. The cooling medium is circulating water. The temperature is controlled within the range of 5-10°C, which can effectively condense the gas generated by pyrolysis.

[0048] The laser transmitter is installed on the top inner side of the tunnel pyrolysis furnace. It uses a long-wave laser transmitter with a wavelength of 900nm-1200nm and an adjustable power range of 500W-2000W. The laser transmitter is equipped with a scanning system, including a scanning mirror and a control system in the XY direction. The scanning angle can be adjusted within the range of ±30°, and the scanning speed can be adjusted within the range of 0.1-1 m / s. The installation height of the laser transmitter is 10-50m / s from the conveyor belt surface to ensure that the laser can evenly irradiate the surface of the photovoltaic module.

[0049] The air inlet pipeline is connected to the inert gas source, which is used to fill the tunnel pyrolysis furnace with inert gas during the pyrolysis process. The inert gas source is a nitrogen cylinder group equipped with a pressure reducing valve and a flow meter, which can provide a stable nitrogen flow. The nitrogen purity is 99.99%, the maximum gas supply pressure is 0.5MPa, and the adjustable flow range is 0-50L / min. The introduction of inert gas can effectively reduce the generation of oxides during the pyrolysis process, improve the pyrolysis efficiency and product quality.

[0050] The laser transmitter is a single long-wave laser transmitter, using a semiconductor laser with a wavelength of 1064nm, a maximum output power of 2000W, and an adjustable laser spot diameter range of 5mm-20mm. The laser transmitter is equipped with a cooling system, which uses water cooling to ensure long-term stable operation. The control system of the laser transmitter can realize power regulation, scanning path planning and scanning speed control to meet the pyrolysis requirements of photovoltaic modules of different specifications.

[0051] In another embodiment, the laser emitters are arranged in an array to cover the width of the conveyor belt. The array laser emitter consists of multiple units, each unit has a power of 200W-500W, a wavelength of 1064nm, a unit spacing of 0.1m-0.5m, and a total coverage width of 2m, which matches the width of the pyrolysis furnace. The array-arranged laser emitters can simultaneously perform full-width pyrolysis treatment on the photovoltaic modules on the conveyor belt to improve the pyrolysis efficiency. Each laser unit can independently control the switch and power, and flexibly adjust the working state according to the size and shape of the photovoltaic module.

[0052] The conveyor belt is a continuous belt or a discontinuous group. In the continuous mode, the conveyor belt is a whole metal mesh belt, forming a closed loop structure, driven by a single drive motor. In the discontinuous mode, the conveyor belt consists of several groups of independent conveying units, each group is 1 meter to 3 meters long, and the speed and direction can be independently controlled to meet the needs of different process sections. Discontinuous conveyor belt groups can achieve segmented control, improving the flexibility and adaptability of the system.

[0053] The film removal rate is determined by the following method:

[0054] 1. Determination of initial film quality

[0055] Equipment: high-precision electronic balance (accuracy 0.1g); laminator.

[0056] Operation: Place the backplane-free component on an electronic balance and record the total mass M1; heat the component at 150°C with a laminator to separate the glass layer and the silicon wafer layer, and use an ultrasonic cleaner (power 200W, frequency 40kHz) to clean the residue for 10 minutes to remove particles attached to the surface; dry the residue in a 105°C oven for 2 hours, cool to room temperature, and weigh the residue mass and record it as M2;

[0057] Calculation of initial film mass:

[0058]

[0059] 2. Determination of the quality of residual film after pyrolysis

[0060] Collect the residues (glass, silicon wafers, etc.) after pyrolysis treatment into a sealed bag; use an ultrasonic cleaner (power 200W, frequency 40kHz) to clean the residues for 10 minutes to remove particles attached to the surface;

[0061] The cleaned residue was placed in an oven at 105°C and dried for 2 hours, and then cooled to room temperature; the total mass of the dried residue was weighed, M3;

[0062] 3. Calculation of residual mass of film

[0063]

[0064] Embodiment 1:

[0065] Method steps:

[0066] Furnace loading: Place the single-glass photovoltaic module with the back sheet removed on the conveyor belt with the glass side facing downward, send it into the pyrolysis furnace, and close the furnace door. The temperature of the pyrolysis furnace is at room temperature.

[0067] The laser is a pulsed laser with an average power of 800W and a spot diameter of 10mm. The scanning path is an "S"-shaped reciprocating motion with a scanning speed of 0.5m / s.

[0068] The total pyrolysis time was 8 minutes, and the film removal rate was 99.2%;

[0069] Gas treatment: Pyrolysis gas is condensed to recover organic matter (EVA decomposition products), and the residual gas is adsorbed by activated carbon and then discharged;

[0070] Residue output: Open the furnace door and the conveyor belt will deliver the glass, silicon wafers and other residues to the sorting station.

[0071] Equipment configuration:

[0072] Tunnel pyrolysis furnace: The shell size is 3m×2m×1m (length×width×height), and the component inlet and residue outlet are equipped with airtight furnace doors (sealing pressure ≥0.1MPa);

[0073] Conveyor belt: discontinuous stainless steel conveyor belt, with high temperature resistant ceramic layer coated on the surface (temperature resistance ≥300℃), and the adjustable running speed range is 0.5m / s;

[0074] Laser transmitter: a single long-wave laser, installed directly above the conveyor belt;

[0075] Gas system: The air inlet pipeline is connected to a 99.9% pure nitrogen source, and the exhaust pipeline is equipped with a condensing device and an activated carbon adsorption tower.

[0076] Embodiment 2:

[0077] The difference between Example 2 and Example 1 is that:

[0078] Method steps:

[0079] Furnace loading and nitrogen filling: Place the single-glass photovoltaic module with the back sheet removed on the conveyor belt with the glass side facing downward, send it into the pyrolysis furnace, close the furnace door, fill it with nitrogen, keep the oxygen content in the furnace <5% (volume fraction), and keep the pyrolysis furnace temperature at room temperature;

[0080] The total pyrolysis time was 3 minutes, and the film removal rate was 99.6%;

[0081] Residue output: Open the furnace door and the conveyor belt will deliver the glass, silicon wafers and other residues to the sorting station.

[0082] Equipment configuration:

[0083] Laser emitter: 6 groups of long-wave lasers are arranged in a linear array with a spacing of 0.3m, covering a 2m wide conveyor belt; the array laser scans synchronously, the power of a single laser emitter is set to 400W, and the spot diameter is 10mm; the scanning path is an "S"-shaped reciprocating motion, and the scanning speed is 1m / s; the scanning angle of the outermost laser emitter is tilted by 15° to reduce unnecessary reflections of the laser;

[0084] Conveyor belt: Continuous stainless steel conveyor belt, with high temperature resistant ceramic layer coated on the surface (temperature resistance ≥300℃), running speed is 0.2m / s;

[0085] Embodiment 3:

[0086] The difference between Example 3 and Example 1 is that:

[0087] Equipment configuration:

[0088] Conveyor belt: Continuous stainless steel conveyor belt, with high temperature resistant ceramic layer coated on the surface (temperature resistance ≥300℃), running speed 1m / s;

[0089] Comparative Example

[0090] Pyrolysis of backsheet-free modules using aerobic pyrolysis:

[0091] Pyrolysis temperature: 500℃±10℃, time: 35 minutes;

[0092] Film removal rate: 85%;

[0093] Energy consumption: 15.5kWh / piece;

[0094] Technical Effect Comparison Table

[0095] index Example 1 Example 2 Example 3 Comparative Example Film removal rate (%) 99.2 99.6 99.2 95 Pyrolysis furnace temperature (℃) 20 20 20 500 Energy consumption (kWh / unit) 0.10 0.12 0.10 15.5 Processing efficiency (pieces / hour) 8 20 8 2

[0096] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can easily think of various equivalent modifications or substitutions within the technical scope disclosed by the present invention, and these modifications or substitutions should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention shall be based on the protection scope determined by the claims.

Claims

1. A laser pyrolysis method for a single-glass photovoltaic module, characterized in that: The following steps are involved: a. Preheat the single-glass waste photovoltaic modules to 100℃~200℃; b. Remove the backboard to obtain a backboard-free module; c. placing the backboard-free assembly with the glass surface facing the conveyor belt (30) and conveying it into the tunnel pyrolysis furnace (20); d. closing the furnace door (70) of the component inlet (610) and the residue outlet (620); e. Turning on the laser transmitter (80) to scan the components without backboard and thermally decompose the adhesive film; f. Extract and condense pyrolysis gas; g. Open the furnace door (70) at the residue outlet (620), and send the pyrolysis residue out of the tunnel pyrolysis furnace (20) via a conveyor belt (30) to the next process.

2. The laser pyrolysis method of a single-glass photovoltaic module according to claim 1, characterized in that: The step d further comprises: after closing the furnace door (70) of the component inlet (610) and the residue outlet (620), an inert gas is introduced into the tunnel pyrolysis furnace (20) to reduce the generation of oxides during the pyrolysis process.

3. The laser pyrolysis method of a single-glass photovoltaic module according to claim 1, characterized in that: The step e also includes: adjusting the scanning angle and scanning speed of the laser emitter (80) according to the size of the single-glass photovoltaic module.

4. The laser pyrolysis method for a single-glass photovoltaic module according to claim 1, characterized in that: In step e, the laser emitter (80) emits long-wave laser light with a wavelength of 900 nm to 1200 nm.

5. A laser pyrolysis device for single-glass photovoltaic modules, characterized in that: A laser pyrolysis method for a single-glass photovoltaic module as claimed in any one of claims 1 to 4, comprising: a tunnel pyrolysis furnace (20) and a conveyor belt (30), wherein the tunnel pyrolysis furnace comprises an air intake pipeline (40), an exhaust pipeline (50) and a shell (60), wherein the shell has a module inlet (610) and a residue outlet (620), wherein the module inlet (610) and the residue outlet (620) are respectively provided with furnace doors (70), wherein the conveyor belt (30) passes through the module inlet (610) and the residue outlet (620), and wherein a laser emitter (80) is arranged inside the shell (60) for emitting laser to pyrolyze a photovoltaic film.

6. The single-glass photovoltaic module laser pyrolysis equipment according to claim 5, characterized in that: The air inlet pipeline (40) is connected to an inert gas source and is used to fill the tunnel pyrolysis furnace (20) with inert gas during the pyrolysis process.

7. The single-glass photovoltaic module laser pyrolysis equipment according to claim 5, characterized in that: The laser emitter (80) is a single long-wave laser emitter.

8. The single-glass photovoltaic module laser pyrolysis equipment according to claim 5, characterized in that: The laser emitters (80) are arranged in an array, covering the width direction of the conveyor belt (30).

9. The single-glass photovoltaic module laser pyrolysis equipment according to claim 5, characterized in that: The conveyor belt (30) is a continuous belt or a discontinuous group.

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