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CN-121972488-A - Photovoltaic module recycling method and system

CN121972488ACN 121972488 ACN121972488 ACN 121972488ACN-121972488-A

Abstract

The invention discloses a recycling recovery method and system of a photovoltaic module, wherein the method comprises the following steps of 1) carrying out primary pyrolysis on the photovoltaic module at 450-550 ℃ under the protection of nitrogen, collecting pyrolysis oil, pyrolysis gas and solid residues, 2) carrying out secondary pyrolysis on the solid residues obtained in the step 1) at 500-600 ℃ under the condition of introducing compressed air, and 3) extracting valuable metals of silver, lead and tin from the pyrolysis residues obtained in the step 2) by controlling the flow rate of the compressed air to 0.5-2.0L/min to regulate and control the decomposition degree of organic matters according to 1kg of materials. The invention realizes complete decomposition of organic matters and clean glass surface, and realizes that the yield of pyrolysis oil is more than 12wt%, the enrichment degree of silver in residues is more than 0.2%, and the recovery rate of lead/tin is more than 95%, and no heavy metal wastewater is discharged in the whole process.

Inventors

  • LIU ZHAN
  • JIANG QINGPAN
  • WANG HONGLIANG

Assignees

  • 国能龙源环保有限公司

Dates

Publication Date
20260505
Application Date
20260115

Claims (10)

  1. 1. The photovoltaic module recycling method is characterized by comprising the following steps of: 1) Under the protection of nitrogen, carrying out primary pyrolysis on the photovoltaic module at 450-550 ℃ and collecting pyrolysis oil, pyrolysis gas and solid residues; 2) Carrying out secondary pyrolysis on the solid residues obtained in the step 1) under the condition of introducing compressed air at 500-600 ℃, and controlling the decomposition degree of organic matters by controlling the compressed air flow to 0.5-2.0L/min based on 1kg of materials to obtain pyrolysis residues; 3) Extracting valuable metals of silver, lead and tin from the pyrolysis residue obtained in the step 2); wherein the temperature of the primary pyrolysis is lower than the temperature of the secondary pyrolysis.
  2. 2. The method for recycling the photovoltaic module according to claim 1, wherein in the step 1), the nitrogen flow is kept at 1-3L/min, the oxygen content is less than or equal to 100 ppm, and the pyrolysis time is 30-90 min based on 1kg of materials.
  3. 3. The method for recycling of photovoltaic modules according to claim 1 or 2, characterized in that in step 1), the photovoltaic modules are subjected to a pretreatment including slightly breaking the glass panels of the surface, before the pyrolysis in step 1).
  4. 4. The method for recycling a photovoltaic module according to any one of claims 1 to 3, wherein in step 1), the method further comprises a step of purifying the pyrolysis product, preferably, the pyrolysis oil obtained is condensed and separated to have a heat value of not less than 35 MJ/kg and an acid value of not more than 5mg KOH/g.
  5. 5. The method for recycling photovoltaic modules according to any one of claims 1 to 4, wherein in step 2), the compressed air flow is 1.0 to 1.5L/min and the pyrolysis time is 20 to 60min, based on 1kg of material.
  6. 6. The method for recycling of photovoltaic modules according to claim 1, wherein in step 3), silver, lead and tin are selectively recovered from the residue by hydrometallurgy.
  7. 7. A photovoltaic module recycling system is characterized in that the system comprises: The anaerobic pyrolysis unit is used for carrying out primary pyrolysis on the photovoltaic module at the temperature of 450-550 ℃ under the condition of nitrogen protection; the aerobic pyrolysis unit is used for carrying out secondary pyrolysis on solid residues obtained by primary pyrolysis under the condition of compressed air at 500-600 ℃, wherein the temperature of the primary pyrolysis is lower than that of the secondary pyrolysis; And the metal leaching unit is used for extracting valuable metals of silver, lead and tin from pyrolysis residues obtained by secondary pyrolysis in a wet method.
  8. 8. The photovoltaic module recycling system according to claim 7, wherein the anaerobic pyrolysis unit is a pyrolysis furnace, and is respectively communicated with a nitrogen gas inlet system and a condensation recycling unit.
  9. 9. The photovoltaic module recycling system according to claim 7 or 8, wherein the aerobic pyrolysis unit is a pyrolysis furnace, and is respectively communicated with the compressed air supply system, the tail gas treatment unit and the residue discharge mechanism.
  10. 10. The photovoltaic module recycling system according to any one of claims 7 to 9, wherein the compressed air supply system of the aerobic pyrolysis unit comprises a flow meter, a pressure regulating valve and a gas distributor, and/or the metal leaching unit comprises a reaction kettle and a solid-liquid separator communicated with the reaction kettle.

Description

Photovoltaic module recycling method and system Technical Field The invention relates to the technical field of new energy solid waste recycling and recovery, in particular to a photovoltaic module recycling and recovery method and system. Background In order to alleviate the problem of global energy shortage, photovoltaic industry is being developed greatly all over the world. At the same time, a large number of waste photovoltaic cell panels will need to be disposed of worldwide. The recovery of the waste crystalline silicon photovoltaic module by the pyrolysis technology has remarkable advantages. Firstly, organic matters and other pollutants in the crystalline silicon photovoltaic module can be effectively removed through pyrolysis, so that the efficiency and feasibility of a subsequent recovery process are improved. And secondly, the pyrolysis can decompose materials such as silicon chips, glass, metals and the like into compounds in an original form or easy to process, so that the subsequent material recovery and reuse are facilitated. In addition, the pyrolysis process is also beneficial to reducing the volume and toxicity of the waste, and is beneficial to recycling of resources and environmental protection. However, the existing pyrolysis recovery technology of the photovoltaic module generally adopts an anaerobic pyrolysis or aerobic pyrolysis mode, and the pyrolysis temperature is constant, so that the following problems exist: The whole-process anaerobic pyrolysis mode is adopted, although oil can be produced, silver remains on the surface of the silicon wafer, the recovery rate is low (80 percent), and the carbon content in the residue is high, so that the subsequent metallurgy is influenced; The method adopts a whole-process aerobic pyrolysis mode, namely the organic matters are thoroughly decomposed, but the yield of pyrolysis oil is zero, metals such as lead, tin and the like are oxidized and fixed on a silicon wafer, the recovery is difficult, and the organic matters are not thoroughly decomposed due to uneven air flow distribution in the aerobic pyrolysis process, so that the residual on the surface of glass affects the subsequent treatment. The pyrolysis oil quality and the metal recovery efficiency cannot be considered in a single-temperature pyrolysis mode. Therefore, the problems of low metal recovery rate, poor quality of pyrolysis products, environmental pollution and the like still exist in the prior pyrolysis technology. Disclosure of Invention Aiming at the defects, the invention mainly aims to provide a photovoltaic module recycling method and system, which realize complete decomposition of organic matters and clean glass surface, realize pyrolysis oil yield of more than 12wt%, silver enrichment degree of more than 0.2% in residues and lead/tin recovery rate of more than 95%, and have no heavy metal wastewater discharge in the whole process. In order to achieve the above purpose, the invention provides a photovoltaic module recycling method, which comprises the following steps: 1) Under the protection of nitrogen, carrying out primary pyrolysis on the photovoltaic module at 450-550 ℃ and collecting pyrolysis oil, pyrolysis gas and solid residues; 2) Carrying out secondary pyrolysis on the solid residue obtained in the step 1) under the condition of introducing compressed air at 500-600 ℃, and controlling the decomposition degree of organic matters by controlling the flow rate of the compressed air to 0.5-2.0L/min (calculated by 1kg of material), so as to obtain pyrolysis residue; 3) Extracting valuable metals of silver, lead and tin from the pyrolysis residue obtained in the step 2); wherein the temperature of the primary pyrolysis is lower than the temperature of the secondary pyrolysis. The second aspect of the invention provides a photovoltaic module recycling system, comprising: The anaerobic pyrolysis unit is used for carrying out primary pyrolysis on the photovoltaic module at the temperature of 450-550 ℃ under the condition of nitrogen protection; The aerobic pyrolysis unit is used for carrying out secondary pyrolysis on solid residues obtained by primary pyrolysis under the condition of compressed air at 500-600 ℃, wherein the temperature of the primary pyrolysis is lower than that of the secondary pyrolysis; And the metal leaching unit is used for extracting valuable metals of silver, lead and tin from pyrolysis residues obtained by secondary pyrolysis in a wet method. The beneficial effects of the invention are as follows: According to the method and the system provided by the invention, the photovoltaic module is subjected to primary anaerobic pyrolysis at 450-550 ℃ under the protection of nitrogen, so that organic matters such as EVA (ethylene vinyl acetate) and backboard are converted into pyrolysis oil and pyrolysis gas, and meanwhile, low-melting-point metals such as lead and tin are melted and collected in solid residues, so that the anaerobic pyrolysis preferenti