A system for recycling retired photovoltaic modules based on the synergistic effect of pyrolysis and quenching

Abstract

The utility model discloses a kind of resource recycling system of decommissioned photovoltaic module based on pyrolysis and quenching synergism, the system uses modular integrated design, in turn include the pretreatment module for cutting, cleaning and drying to the photovoltaic module board after frame removal along material processing direction;For the pyrolysis and condensation module of photovoltaic module is pyrolyzed and condenses oil-gas mixture to realize the separation of glass, cell piece and packaging material;For the quenching module for making metal layer from silicon wafer surface peeling by quenching treatment.The utility model uses the recovery system of pyrolysis and quenching synergism, by the organic combination of organic material pyrolysis and metal-silicon interface cold brittle separation, realizes the efficient recovery of photovoltaic module full component.

Description

Technical Field

[0001] This utility model belongs to the field of resource recycling technology for retired photovoltaic modules, specifically relating to a resource recycling system for retired photovoltaic modules based on the synergistic effect of pyrolysis and rapid cooling. Background Technology

[0002] With the global energy structure transitioning towards green and low-carbon practices, the installed capacity of photovoltaic power generation continues to grow rapidly. How to achieve environmentally friendly and economically efficient recycling of retired photovoltaic modules has become a pressing issue globally. Crystalline silicon photovoltaic modules, as the mainstream product in the market, are mainly composed of tempered glass, encapsulating films such as ethylene-vinyl acetate copolymer (EVA), silicon solar cells, metal electrodes, a backsheet, and an aluminum frame. The various layers are tightly bonded together by polymer encapsulating films, and this stable structure presents a significant challenge to efficient and complete resource recycling.

[0003] Currently, the resource recycling technology for retired crystalline silicon photovoltaic modules has the following limitations: Physical recycling mainly uses mechanical crushing and sorting, which are simple and low-cost, but have low recovery rates and poor separation purity. Due to the strong adhesive effect of the encapsulation materials, it is difficult to achieve effective separation of glass, cells and metals by relying solely on physical force. Chemical recycling usually uses high-temperature pyrolysis combined with strong acid / base chemical etching, which generates a large amount of acidic wastewater containing heavy metals and fluorides, posing a risk of secondary pollution. At the same time, strong acids and bases corrode the silicon substrate, reducing the purity and value of the recycled silicon powder.

[0004] Therefore, there is an urgent need to develop a new, environmentally friendly green recycling system that can achieve efficient recovery of all components. Utility Model Content

[0005] To address the aforementioned problems, the purpose of this invention is to provide a resource recovery system for decommissioned photovoltaic modules based on the synergistic effect of pyrolysis and rapid cooling.

[0006] The specific technical solution is as follows: A resource recovery system for decommissioned photovoltaic modules based on the synergistic effect of pyrolysis and rapid cooling. This system adopts a modular integrated design and includes, sequentially along the material handling direction, […]. A pretreatment module used for cutting, cleaning, and drying photovoltaic module panels after the frames have been removed; A pyrolysis and condensation module used to pyrolyze and condense oil-gas mixtures in photovoltaic modules to achieve the separation of glass, cells and encapsulation materials; A rapid cooling module used to peel metal layers off the surface of a silicon wafer through a rapid cooling process.

[0007] Furthermore, the pretreatment module includes a water jet cutting unit for cutting photovoltaic modules and a cleaning and drying unit for removing dust from the surface of photovoltaic modules and drying the photovoltaic modules, with the cleaning and drying unit located downstream of the water jet cutting unit.

[0008] Furthermore, the cleaning and drying unit includes a high-pressure airflow purging device for removing dust from the surface of the photovoltaic modules and a hot air circulation drying device for drying the photovoltaic modules. The waterjet cutting unit includes a gantry waterjet cutter, the high-pressure airflow purging device is an airflow scrubber, and the hot air circulation drying device is a tunnel-type hot air circulation oven.

[0009] Furthermore, the pyrolysis and condensation module includes a pyrolysis unit, a condensation unit, and a tail gas treatment unit. The pyrolysis unit includes a pyrolysis furnace, the condensation unit includes a first condenser and a second condenser, and the tail gas treatment unit includes an alkaline spray purification device. The outlet of the pyrolysis furnace is connected to the first condenser and the second condenser in sequence, and the outlet of the second condenser is connected to the alkaline spray purification device, which is a spray tower with alkaline solution as the absorbent.

[0010] Furthermore, the quenching module includes a quenching unit for quenching and a screening unit for sorting the battery cells. The quenching unit is a liquid nitrogen quenching device, which is a cryogenic liquid nitrogen tank. The screening unit includes a sorting machine.

[0011] The beneficial effects of this utility model are as follows: The system employs a pyrolysis and quenching synergistic recovery system. By combining the pyrolysis of organic materials with the cold brittle separation of the metal-silicon interface, it achieves efficient recovery of all components of the photovoltaic module. Pollutants such as fluorine-containing gases generated during pyrolysis are thoroughly purified by an alkaline spray purification device. There is no wastewater discharge. The quenching module replaces the traditional acid etching process, eliminating the risk of heavy metal pollution at the source. Attached Figure Description

[0012] Figure 1 This is a flowchart illustrating the system of this utility model. Detailed Implementation

[0013] The present invention will be further described below with reference to the accompanying drawings and embodiments, but the scope of protection of the present invention is not limited thereto.

[0014] like Figure 1 As shown, a resource recycling system for decommissioned photovoltaic modules based on the synergistic effect of pyrolysis and rapid cooling adopts a modular integrated design, with materials passing sequentially through the following three core modules along the conveyor belt: Pretreatment module: includes water jet cutting unit and cleaning and drying unit; pyrolysis and condensation module: includes pyrolysis unit, condensation unit and exhaust gas treatment unit; quench module: includes quench unit and screening unit. The waterjet cutting unit includes a gantry-type waterjet cutter, which uses ultra-high pressure water jets to precisely cut the entire photovoltaic module panel with the frame removed into specified dimensions; The cleaning and drying unit is located downstream of the waterjet cutting unit and includes a high-pressure airflow purging device and a hot air circulation drying device. First, the high-pressure airflow purging device removes cutting residues and dust from the surface of the sample. Then, the sample enters the hot air circulation drying device to ensure that the surface moisture of the sample is completely evaporated. The high-pressure airflow purging device is an airflow scrubber, and the hot air circulation drying device is a tunnel-type hot air circulation oven. The pyrolysis unit uses an inert gas-protected pyrolysis furnace for pyrolysis; The condensation unit includes a first-stage condenser and a second-stage condenser, which condense the pyrolysis oil and gas. The exhaust gas treatment unit is connected to the condensation unit and includes an alkaline spray purification device for treating non-condensable gases and fluorine-containing pollutants generated by pyrolysis. The alkaline spray purification device is a spray tower with alkaline solution as the absorbent. The gas outlet of the pyrolysis furnace is connected in sequence to the first condenser and the second condenser, and the outlet of the second condenser is connected to the alkaline spray purification device.

[0015] The rapid cooling unit uses a liquid nitrogen refrigeration device for rapid cooling, which is a cryogenic liquid nitrogen bath. The screening unit is used to sort the solar cells after rapid cooling. The sorting adopts airflow sorting and electrostatic sorting.

[0016] Example 1 S1. Pre-treatment: The crystalline silicon photovoltaic module panel after mechanically removing the frame is sent into the pre-treatment module via conveyor belt. It is cut into 15cm×15cm samples using an ultra-high pressure water jet with a working pressure of 300MPa. The samples then enter the cleaning and drying unit, where they are first blown with 0.4MPa compressed air to remove dust, and then dried in 40℃ hot air for 60 minutes to ensure complete drying. S2. Pyrolysis and Condensation: The dried sample is conveyed into a nitrogen-filled pyrolysis furnace via a conveyor device. It is preheated from room temperature to 300°C at a rate of 10°C / min and held at that temperature for 30 minutes. Then, it is raised to 450°C at a rate of 10°C / min and held at that temperature for 45 minutes. During this process, the encapsulation material is completely pyrolyzed into oil and gas. The pyrolysis oil and gas are condensed in two stages. The first stage condenser uses 25°C circulating water to recover most of the pyrolysis oil. The second stage condenser uses 25°C circulating water to further recover a small amount of oil. The non-condensable gas is purified by an alkaline spray tower before being discharged. After pyrolysis is completed, the pyrolysis furnace is opened. Due to the loss of the adhesive of the encapsulation material, the upper glass cover can be removed and recycled as a whole or in large pieces. The remaining mixture of battery cells and backsheet debris is sent to the next process.

[0017] S3. Rapid Cooling and Sorting: Through simple mechanical vibration and sieving, the solar cells are separated from the mixture. The solar cells are placed in a rapid cooling module and rapidly cooled in a liquid nitrogen environment at -190°C for 20 minutes. The brittle solar cells after rapid cooling are sent to a sorting machine that integrates airflow sorting and high-voltage electrostatic sorting functions to achieve the separation of metal materials from silicon.

Claims

1. A resource recovery system for decommissioned photovoltaic modules based on the synergistic effect of pyrolysis and rapid cooling, characterized in that, The system adopts a modular integrated design, and includes, sequentially along the material handling direction, the following components: A pretreatment module used for cutting, cleaning, and drying photovoltaic module panels after the frames have been removed; A pyrolysis and condensation module used to pyrolyze and condense oil-gas mixtures in photovoltaic modules to achieve the separation of glass, cells and encapsulation materials; A rapid cooling module used to peel metal layers off the surface of a silicon wafer through a rapid cooling process.

2. The resource recovery system for decommissioned photovoltaic modules based on the synergistic effect of pyrolysis and rapid cooling as described in claim 1, characterized in that, The pretreatment module includes a water jet cutting unit for cutting photovoltaic modules and a cleaning and drying unit for removing dust from the surface of photovoltaic modules and drying the photovoltaic modules. The cleaning and drying unit is located downstream of the water jet cutting unit.

3. The resource recovery system for decommissioned photovoltaic modules based on the synergistic effect of pyrolysis and rapid cooling as described in claim 2, characterized in that, The cleaning and drying unit includes a high-pressure airflow purging device for removing dust from the surface of the photovoltaic modules and a hot air circulation drying device for drying the photovoltaic modules.

4. The resource recovery system for decommissioned photovoltaic modules based on the synergistic effect of pyrolysis and rapid cooling as described in claim 1, characterized in that, The pyrolysis and condensation module includes a pyrolysis unit, a condensation unit, and a tail gas treatment unit. The pyrolysis unit includes a pyrolysis furnace, the condensation unit includes a first condenser and a second condenser, and the tail gas treatment unit includes an alkaline spray purification device. The outlet of the pyrolysis furnace is connected to the first condenser and the second condenser in sequence, and the outlet of the second condenser is connected to the alkaline spray purification device.

5. The resource recovery system for decommissioned photovoltaic modules based on the synergistic effect of pyrolysis and rapid cooling as described in claim 1, characterized in that, The quenching module includes a quenching unit for quenching and a screening unit for sorting the solar cells. The quenching unit is a liquid nitrogen quenching device.

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