Continuous heating device, and recovery system of constituent member of solar cell panel

Abstract

The present invention provides a continuous heating device that improves thermal efficiency in heat treatment of a solar cell panel, can reduce energy cost, and improves quality of valuables recovered from a solar cell panel. The present invention also provides a recovery system of a constituent member of a solar cell panel, the recovery system including the continuous heating device.　A continuous heating device (100) is provided with a heating furnace (20). The heating furnace (20) has: a primary treatment unit (13) for obtaining a primary treatment product (2) by heat treating a solar cell panel (1) transported by an endless belt (21) in a non-oxidizing atmosphere; and a secondary treatment unit (15) for obtaining a heat-treated product (3) by heat treating the primary treatment product (2) transported by the endless belt (21) in an oxidizing atmosphere. The primary treatment unit (13) and / or the secondary treatment unit (15) utilizes thermal energy generated by combustion of pyrolysis gas generated when a sealing material of the solar cell panel (1) is heat treated by the primary treatment unit (13) and decomposed.

Description

Continuous heating equipment, recovery system for solar panel components

[0001] The present invention relates to a continuous heating device and a recovery system for components of a solar cell panel.

[0002] In order to make effective use of resources, the recovery of cells and glass from used solar panels is being considered. As the amount of discarded solar panels is expected to increase, the importance of reusing their components is growing. For example, by removing the aluminum frame of a solar panel, the aluminum plate can be recovered. In addition, by removing resins such as adhesives and sealants from solar panels, the glass, copper wire, and silicon cells can be recovered.

[0003] Methods for removing resins such as encapsulants from solar cell panels include wet treatment methods that use a treatment solution to decompose or separate the resin, and treatment methods that vaporize the resin through heat treatment. However, heat treatment is preferred in terms of continuous processing. For example, Patent Document 1 discloses a method for heat-treating solar cell panels and then separating and recovering glass materials and metal-containing materials from the heat-treated product. In the examples of Patent Document 1, organic compounds in the solar cell panels are decomposed by performing a primary baking in a nitrogen atmosphere followed by a secondary baking in air.

[0004] JP 2023-89446 A

[0005] However, in the heating furnace used in the examples of Patent Document 1, the photovoltaic solar panel is subjected to a primary firing in a nitrogen atmosphere, and then the heat-treated product is cooled once before the secondary firing. Therefore, the treated product obtained in the primary firing needs to be heated again for the secondary firing. As a result, there are problems such as poor thermal efficiency in the heat treatment of the photovoltaic solar panel and high energy costs. In addition, soot derived from resin residue may adhere to the heat-treated product, which may cause variations in the quality of valuable materials recovered in the sorting process after the heat treatment.

[0006] The present invention provides a continuous heating device that improves the thermal efficiency in the heat treatment of solar cell panels, reduces energy costs, and improves the quality of valuable materials recovered from solar cell panels; and a solar cell panel component recovery system that is equipped with the continuous heating device.

[0007] The present invention has the following aspects. [1] A continuous heating apparatus including a heating furnace that heat-treats photovoltaic panels while transporting them on an endless belt to obtain a heat-treated product, the heating furnace having a primary processing section that heat-treats the photovoltaic panels in a non-oxidizing atmosphere while transporting them on the endless belt to obtain a primary processed product, and a secondary processing section that heat-treats the primary processed product in an oxidizing atmosphere while transporting it on the endless belt to obtain the heat-treated product, wherein at least one of the primary processing section and the secondary processing section utilizes thermal energy generated by combustion of pyrolysis gas that is generated when a sealant for the photovoltaic panels is decomposed by heat treatment in the primary processing section. [2] The continuous heating apparatus according to [1], wherein a flexible seal curtain that crosses the transport direction of the photovoltaic panels and is in contact with the endless belt is suspended at at least one location within the heating furnace. [3] The continuous heating apparatus according to [2], wherein the seal curtain is suspended within the heating furnace between the primary processing section and the secondary processing section. [4] The continuous heating apparatus according to [2] or [3], wherein the seal curtain is suspended in the heating furnace upstream of the primary treatment section. [5] The continuous heating apparatus according to any one of [2] to [4], wherein the seal curtain is suspended in the heating furnace downstream of the secondary treatment section. [6] The continuous heating apparatus according to any one of [1] to [5], wherein at least one of the primary treatment section and the secondary treatment section utilizes the thermal energy of the exhaust gas generated after the pyrolysis gas is combusted. [7] The continuous heating apparatus according to any one of [1] to [6], further comprising a combustion chamber for combusting the pyrolysis gas generated when the sealing material of the solar cell panel is thermally treated and decomposed in the primary treatment section. [8] The continuous heating apparatus according to [7], wherein at least one of the primary treatment section and the secondary treatment section utilizes the thermal energy of the exhaust gas discharged from the combustion chamber. [9] The continuous heating apparatus according to any one of [1] to [8], wherein a heat exchanger utilizing the thermal energy generated by the combustion of the pyrolysis gas is disposed in at least one of the primary treatment section and the secondary treatment section.

[10] The continuous heating apparatus according to [9], wherein the heat exchanger utilizes thermal energy of exhaust gas generated after burning the pyrolysis gas.

[11] The continuous heating apparatus according to [9] or

[10] , wherein the heating furnace has a muffle surrounding the endless belt so as to cover it, and an outer wall surrounding the muffle so as to cover it, and the heat exchanger is disposed in the space between the muffle and the outer wall.

[12] The continuous heating apparatus according to any of [9] to

[11] , wherein the heat exchanger is an indirect heat exchanger.

[13] The continuous heating apparatus according to

[11] or

[12] , wherein an electric heater is disposed in the space between the muffle and the outer wall.

[14] The continuous heating apparatus according to any of [1] to

[13] , wherein the amount of soot adhesion on the heat-treated product is 100 ppm or less.

[15] A recovery system for components of a photovoltaic panel, comprising: the continuous heating device according to any one of [1] to

[14] ; and a sorting device that separates glass materials and materials containing valuable metals from the heat-treated product.

[16] The recovery system for components of a photovoltaic panel according to

[15] , wherein the sorting device has a sieving process section that separates the heat-treated product into first materials containing valuable metals including cells and copper wires and a first glass material.

[17] The recovery system for components of a photovoltaic panel according to

[16] , wherein the sorting device further has an air sorting section that separates the first glass material separated by the sieving process section into second materials containing valuable metals including cells and a second glass material by air sorting.

[18] The recovery system for components of a photovoltaic panel according to

[17] , further having an air table sorting section that separates a third glass material from the second glass material using an air table.

[19] The recovery system for components of a solar cell panel according to

[18] , wherein the glass purity of the third glass material after sorting is 99.99% or more.

[20] The recovery system for components of a solar cell panel according to any one of

[15] to

[19] , wherein the recycling rate of the glass material contained in the heat-treated product is 85% or more.

[21] The recovery system for components of a solar cell panel according to any one of

[15] to

[20] , wherein the recycling rate of the cells contained in the heat-treated product is 90% or more.

[22] A recovery system for components of a solar cell panel according to any one of

[15] to

[21] , wherein the recycling rate of copper wire contained in the heat-treated product is 90% or more.

[0008] According to the present invention, the thermal efficiency in the heat treatment of photovoltaic panels is improved, energy costs can be reduced, and the quality of valuable materials recovered from photovoltaic panels is improved.

[0009] FIG. 1 is a schematic diagram showing an example of a continuous heating apparatus. FIG. 2 is a schematic diagram of the continuous heating apparatus of FIG. 1 as viewed from the entrance side. FIG. 3 is a partially enlarged perspective view of the continuous heating apparatus of FIG. 1. FIG. 4 is a view of the seal curtain as viewed from the transport direction of the photovoltaic panels. FIG. 5 is a side view of the photovoltaic panels being transported while pushing up the seal curtain in the sealing chamber of the heating furnace. FIG. 6 is a view of the photovoltaic panels being transported while pushing up the seal curtain in the sealing chamber of the heating furnace as viewed from the rear in the transport direction of the photovoltaic panels. FIG. 7 is a view of the photovoltaic panels being transported while pushing up the seal curtain in the sealing chamber of the heating furnace as viewed from the rear in the transport direction of the photovoltaic panels. FIG. 8 is a schematic diagram showing an example of a recovery system for components of photovoltaic panels. FIG. 9 is a schematic diagram showing another example of a recovery system for components of photovoltaic panels. FIG. 10 shows glass fragments recovered from the heat-treated material obtained in Example 1. FIG. 11 shows glass fragments recovered from the heat-treated material obtained in Comparative Example 1.

[0010] [Terminology] A "non-oxidizing atmosphere" refers to an atmosphere that does not contain oxygen gas or an atmosphere that substantially does not contain oxygen gas. An "oxidizing atmosphere" refers to an atmosphere that contains oxygen gas, other than a non-oxidizing atmosphere. In this specification and claims, the symbol "to" indicating a range of values ​​means that the values ​​before and after it are included as the lower and upper limits.

[0011] [Photovoltaic Panel] In one example, the photovoltaic panel has a cell, a glass substrate, and a sealing material. In another example, the photovoltaic panel may further have wiring electrodes, extraction electrodes, a terminal box, a cable, a back sheet, a frame, etc. It is preferable to perform the heat treatment on the photovoltaic panel after removing the cable. In terms of reducing the number of steps, it is preferable to perform the heat treatment on the photovoltaic panel without removing the back sheet, terminal box, and aluminum frame.

[0012] Examples of solar cell panel cells include silicon-based (single crystal silicon-based, polycrystalline silicon-based, amorphous silicon-based, etc.) and compound-based (GaAs-based, CIS-based, CdTe-CdS-based). Single crystal silicon-based and polycrystalline silicon-based cells are preferred. Examples of glass substrates for solar cell panels include soda lime glass and alkali-free glass. Examples of sealing materials for solar cell panels include ethylene-vinyl acetate copolymer (EVA) and ethylene-(meth)acrylic acid ester copolymer. Of these, EVA is widely used.

[0013] [Pyrolysis Gas] Pyrolysis gas is generated when the encapsulant of a solar cell panel is thermally decomposed. Pyrolysis gas is a gas generated by the thermal decomposition of resins such as encapsulants during the thermal decomposition of the encapsulant of a solar cell panel. Solar cell panels mainly use organic compounds such as various resins and polymers as encapsulants. Constituent elements of these organic compounds include carbon, nitrogen, fluorine, hydrogen, and oxygen. These organic compounds are decomposed by heating and vaporized to generate pyrolysis gas.

[0014] The resin is gasified and carbonized by heat treatment in a non-oxidizing atmosphere in the primary treatment, and then heat treatment in an oxidizing atmosphere in the secondary treatment, which allows the carbides adhering to the heat-treated material after the primary treatment to be oxidized and removed. The pyrolysis gas generated in the primary treatment is larger than the CO generated in the secondary treatment. ２The continuous heating apparatus of the present invention is characterized by utilizing the thermal energy generated by the combustion of pyrolysis gas generated in the primary treatment, which contains more combustible gases than oxidizing gases such as nitrate, nitrate, and nitrate.

[0015] Hereinafter, several embodiments will be described with reference to the drawings as appropriate. The following description relates to representative examples of embodiments of the invention, and the present invention is not limited to the following description. Furthermore, the dimensional ratios in each drawing may differ from the actual ones for the sake of convenience of explanation.

[0016] [Continuous Heating Apparatus] Fig. 1 is a schematic diagram showing an example of a continuous heating apparatus. The continuous heating apparatus 100 includes a heating furnace 20 that heat-treats photovoltaic panels 1 while transporting them on an endless belt 21 to obtain a heat-treated product, a combustion chamber 40 for burning pyrolysis gas generated when the sealing material of the photovoltaic panels 1 is heat-treated and decomposed in the primary treatment section 13 of the heating furnace 20, a first gas supply means (not shown) that supplies an inert gas into the heating furnace 20, and a second gas supply means (not shown) that supplies an oxygen-containing gas into the heating furnace 20.

[0017] The heating furnace 20 has, from upstream to downstream, an inlet-side exhaust chamber 11, an inlet-side sealing chamber 12, a primary processing unit 13, a switching unit 14, a secondary processing unit 15, an air-cooling chamber 16, a cooling chamber 17, an outlet-side sealing chamber 18, and an outlet-side exhaust chamber 19.

[0018] Fig. 2 is a schematic diagram of the continuous heating apparatus 100 of Fig. 1 as seen from the inlet 11a side. Fig. 3 is a partially enlarged perspective view of the continuous heating apparatus 100. As shown in Fig. 2, the heating furnace 20 has a muffle 27 that surrounds the endless belt 21, and an outer wall 28 that surrounds the muffle 27. Although not shown in Fig. 3, the muffle 27 and the outer wall 28 each have a structure that extends in the conveying direction of the endless belt 21. Within the muffle 27, a primary processing unit 13, a switching unit 14, and a secondary processing unit 15 are each formed.

[0019] The outer wall 28 covers the muffle 27, the pair of electric heaters 29, the first heat exchanger 31, the second heat exchanger 32, etc. The outer wall 28 can suppress thermal fluctuations, so that the temperatures of the primary treatment section 13 and the secondary treatment section 15 can be maintained at appropriate heat treatment temperatures. The temperatures can be adjusted by controlling the output of each electric heater 29 according to the temperatures of the primary treatment section 13 and the secondary treatment section 15 in the muffle 27.

[0020] The entrance-side exhaust chamber 11 is formed with an entrance 11a for carrying the photovoltaic panel 1 into the heating furnace 20. The entrance-side exhaust chamber 11 is an area for exhausting the outside air flowing in from the entrance 11a together with the inert gas and pyrolysis gas from the entrance-side sealing chamber 12. In one example, the entrance 11a may be provided with an opening adjustment plate for adjusting the opening of the passage (entrance 11a) of the heating furnace 20.

[0021] An exhaust port 11b is formed at the top of the inlet-side exhaust chamber 11 to exhaust the outside air flowing in from the inlet 11a together with the inert gas and pyrolysis gas from the inlet-side sealing chamber 12. One end of an exhaust pipe 71 is connected to the exhaust port 11b. In one example, the exhaust port 11b may be provided with an opening adjustment means for adjusting its opening degree. An example of the opening adjustment means is an opening adjustment plate.

[0022] The inlet-side sealing chamber 12 is a region for preventing outside air from entering the primary processing section 13 and preventing inert gas and pyrolysis gas from leaking from the primary processing section 13. An inert gas inlet (not shown) is formed at the top of the inlet-side sealing chamber 12 for introducing inert gas supplied from a first gas supply means (not shown) into the inlet-side sealing chamber 12.

[0023] A flexible sealing curtain 22 is suspended in the entrance-side sealing chamber 12, crossing the transport direction of the photovoltaic panel 1 and in contact with the endless belt 21. In one example, the entrance-side sealing chamber 12 may be provided with an opening adjustment plate (not shown) at a position upstream of the sealing curtain 22, which adjusts the opening of the passage of the heating furnace 20 (the entrance of the entrance-side sealing chamber 12).

[0024] The vertical length of the sealing curtain 22 may be any length that allows it to come into contact with the endless belt 21 inside the heating furnace 20. It is preferable that the lower end of the sealing curtain 22 and the endless belt 21 are in contact with each other, and it is more preferable that the lower end of the sealing curtain 22 is pressed against the endless belt 21 and bent.

[0025] The sealing curtain 22 may be any flexible and heat-resistant material. For example, the sealing curtain 22 may be a thin sheet. A thin heat-resistant sheet is preferable, and a thin metal sheet is more preferable.

[0026] In the entrance-side sealing chamber 12, multiple stages of sealing curtains 22 are hung at intervals in the transport direction of the photovoltaic panel 1. The number of stages of the sealing curtain 22 is preferably 2 to 100 stages, more preferably 10 to 85 stages, and even more preferably 20 to 70 stages. If the number of stages of the sealing curtain 22 is equal to or greater than the lower limit of the above range, it is possible to sufficiently prevent outside air from entering the primary processing section 13 and to prevent inert gases and pyrolysis gases from leaking from the primary processing section 13. If the number of stages of the sealing curtain 22 is equal to or less than the upper limit of the above range, it is easy for the photovoltaic panel 1 to pass through the entrance-side sealing chamber 12.

[0027] As shown in FIG. 4 , the seal curtain 22 is composed of multiple strips 22A extending vertically and arranged with no gaps in a direction transverse to the transport direction of the photovoltaic panel 1. The number of strips 22A per meter of the width of the seal curtain 22 is preferably 2 to 50 strips / m, more preferably 10 to 30 strips / m. When the number of strips 22A is equal to or greater than the lower limit of the above range, the gap between the side surface of the photovoltaic panel 1 and the strips 22A can be minimized due to the mechanism of action described below. This sufficiently prevents outside air from entering the primary processing unit 13 and inert gases and pyrolysis gases from leaking from the primary processing unit 13. When the number of strips 22A is equal to or less than the upper limit of the above range, the number of gaps between adjacent strips 22A is reduced. This sufficiently prevents outside air from entering the primary processing unit 13 and inert gases and pyrolysis gases from leaking from the primary processing unit 13.

[0028] The primary treatment section 13 is an area for obtaining a primary treated product by heat-treating the photovoltaic panel 1 in a non-oxidizing atmosphere while transporting it on the endless belt 21. An inert gas inlet (not shown) is formed in the upper part of the primary treatment section 13 for introducing an inert gas supplied from a first gas supply means (not shown) into the primary treatment section 13. As shown in FIG. 2 , a pair of electric heaters 29 are installed in the space between the muffle 27 and the outer wall 28 in the direction of transport by the endless belt 21. The pair of electric heaters 29 are installed in the primary treatment section 13 in the direction of transport of the photovoltaic panel 1, sandwiching the muffle 27 in which the endless belt 21 that transports the photovoltaic panel 1 is arranged.

[0029] In the primary treatment section 13, the photovoltaic panel 1 is heat-treated, thereby pyrolyzing part of the resin contained in the photovoltaic panel 1, and as a result, a primary treatment product 2 is obtained. An exhaust port 13a is formed in the upper part of the primary treatment section 13 for exhausting pyrolysis gas generated by the pyrolysis of resins such as the sealant contained in the photovoltaic panel 1 from the primary treatment section 13 together with inert gas. The pyrolysis gas generated here flows through a pyrolysis gas supply pipe 61 connected to the exhaust port 13a and is supplied to the combustion chamber 40.

[0030] The switching section 14 is an area for switching between primary treatment in a non-oxidizing atmosphere and secondary treatment in an oxidizing atmosphere. An inert gas inlet (not shown) is formed at the top of the switching section 14 for introducing inert gas supplied from a first gas supply means (not shown) into the switching section 14.

[0031] Within the heating furnace 20 of the switching section 14, located between the primary processing section 13 and the secondary processing section 15, multiple stages of sealing curtains 23 are suspended at intervals in the conveying direction of the primary processing material 2. The number of stages of the sealing curtains 23 in the switching section 14 is preferably 2 to 50, more preferably 2 to 30, and even more preferably 5 to 20. If the number of stages of the sealing curtains 23 is equal to or greater than the lower limit of the aforementioned range, leakage of pyrolysis gases and inert gases from the primary processing section 13 to the secondary processing section 15, and leakage of oxidizing gases and oxygen-containing gases from the secondary processing section 15 to the primary processing section 13, are sufficiently suppressed. If the number of stages of the sealing curtains 22 is equal to or less than the upper limit of the aforementioned range, the primary processing material 2 can easily pass through the switching section 14. The details and preferred aspects of the sealing curtain 23 are the same as those of the sealing curtain 22 in the inlet-side sealing chamber 12.

[0032] The secondary treatment section 15 is an area for obtaining a heat-treated product 3 by heat-treating the primary treatment product 2 in an oxidizing atmosphere while being transported by an endless belt 21. An oxygen-containing gas inlet (not shown) is formed at the top of the secondary treatment section 15 for introducing an oxygen-containing gas supplied from a second gas supply means (not shown) into the secondary treatment section 15.

[0033] Within the secondary treatment section 15, a pair of electric heaters 29 (FIG. 2) are installed in the transport direction of the photovoltaic panel 1, sandwiching a muffle 27 in which an endless belt 21 for transporting the primary treatment product 2 is disposed. In the secondary treatment section 15, the primary treatment product 2 is heat-treated, thereby oxidizing carbides of resins such as sealing materials remaining in the primary treatment product 2. As a result, a heat-treated product 3 is obtained in the secondary treatment section 15.

[0034] An exhaust port (not shown) is formed in the upper part of the secondary treatment section 15 for exhausting oxidizing gases generated by oxidation of carbonized resins such as sealing materials remaining in the primary treatment product 2, together with oxygen-containing gas, from the secondary treatment section 15. The exhaust port is preferably formed near the switching section 14, since this can prevent leakage of inert gases and pyrolysis gases from the primary treatment section 13 to the secondary treatment section 15. The oxidizing gases referred to here include, but are not limited to, carbon dioxide gas, water vapor, nitrogen oxides, sulfur oxides, and incomplete combustion products thereof.

[0035] The air-cooling chamber 16 and the cooling chamber 17 are regions for cooling the heat-treatment object 3. A cooling pipe (not shown) for flowing cooling water is disposed in the cooling chamber 17.

[0036] The outlet-side sealing chamber 18 is an area for preventing outside air from entering the cooling chamber 17, the air-cooling chamber 16, and the secondary treatment section 15, and preventing oxygen-containing gas and oxidizing gas from leaking from the secondary treatment section 15, the air-cooling chamber 16, and the cooling chamber 17. An oxygen-containing gas inlet (not shown) is formed in the upper part of the outlet-side sealing chamber 18 for introducing oxygen-containing gas supplied from a second gas supply means (not shown) into the outlet-side sealing chamber 18.

[0037] In the discharge-side sealing chamber 18, flexible sealing curtains 24 that cross the conveying direction of the heat-treatment material 3 and contact the endless belt 21 are suspended in multiple stages at intervals in the conveying direction of the heat-treatment material 3.

[0038] The number of stages of the seal curtain 24 in the outlet-side sealing chamber 18 is preferably 2 to 100, more preferably 10 to 60, and even more preferably 20 to 40. If the number of stages of the seal curtain 24 is equal to or greater than the lower limit of the above range, it is possible to sufficiently prevent outside air from entering the cooling chamber 17 and the secondary treatment unit 15, and to sufficiently prevent oxygen-containing gas and oxidizing gas from leaking from the secondary treatment unit 15 and the cooling chamber 17. If the number of stages of the seal curtain 24 is equal to or less than the upper limit of the above range, it is easy for the heat-treated material 3 to pass through the outlet-side sealing chamber 18.

[0039] The details and preferred aspects of the sealing curtain 24 are the same as those of the sealing curtain 22 in the inlet-side sealing chamber 12. In one example, the outlet-side sealing chamber 18 may be provided with an opening adjustment plate located downstream of the sealing curtain 24 to adjust the opening of the passage of the heating furnace 20 (the outlet of the outlet-side sealing chamber 18).

[0040] The outlet-side exhaust chamber 19 is formed with an outlet 19a for carrying out the heat-treated object 3 from the heating furnace 20. The outlet-side exhaust chamber 19 is a region for exhausting the outside air flowing in from the outlet 19a together with the oxygen-containing gas and oxidizing gas from the outlet-side sealing chamber 18. In one example, the outlet 19a may be provided with an opening adjustment plate for adjusting the opening of the passage (outlet 19a) of the heating furnace 20.

[0041] An exhaust port 19b is formed at the top of the outlet-side exhaust chamber 19 to exhaust the outside air flowing in from the outlet 19a together with the oxygen-containing gas and oxidizing gas from the outlet-side sealing chamber 18. One end of an exhaust pipe 72 is connected to the exhaust port 19b. In one example, the exhaust port 19b may be provided with an opening adjustment means for adjusting the opening degree thereof. An example of the opening adjustment means is an opening adjustment plate.

[0042] The continuous heating device 100 includes a combustion chamber 40 for burning pyrolysis gas generated when the resin of the photovoltaic panel 1 is thermally treated and decomposed in the primary treatment unit 13. Connected to the combustion chamber 40 are a pyrolysis gas supply pipe 61 for supplying the pyrolysis gas generated in the primary treatment unit 13, an LPG supply pipe 63 for supplying LPG in an LPG tank 64, and an air supply pipe 62 for supplying air. Also connected to the combustion chamber 40 is an exhaust pipe 51 for discharging exhaust gas generated when the pyrolysis gas is combusted in the combustion chamber 40. The exhaust pipe 51 is connected to a first reheating line 811 and a second reheating line 821, respectively.

[0043] In the combustion chamber 40, the pyrolysis gas supplied from the primary treatment section 13 through the pyrolysis gas supply pipe 61 is mixed with air and combusted. The exhaust gas generated after burning the pyrolysis gas generated in the primary treatment section 13 flows through the exhaust pipe 51 and is discharged to the outside of the combustion chamber 40, and is then used to heat the primary treatment section 13 and the secondary treatment section 15.

[0044] The exhaust gas discharged from the combustion chamber 40 flows through the first reheat line 811 and the second reheat line 821. Because the exhaust gas discharged from the combustion chamber 40 is at a high temperature, its thermal energy can be utilized by the first heat exchanger 31 and the second heat exchanger 32 connected to the first reheat line 811 and the second reheat line 821, respectively.

[0045] The first heat exchanger 31 and the second heat exchanger 32 each utilize the thermal energy generated by combustion of pyrolysis gas that is generated when the sealant for the photovoltaic panel is thermally treated and decomposed in the primary treatment section 13. In the continuous heating device 100, the pyrolysis gas that is generated when the sealant for the photovoltaic panel is thermally treated and decomposed in the primary treatment section 13 is converted into high-temperature exhaust gas that is generated by a combustion reaction in the combustion chamber 40. Therefore, the first heat exchanger 31 and the second heat exchanger 32 can each utilize the thermal energy of the exhaust gas that is generated after the pyrolysis gas is combusted.

[0046] The first heat exchanger 31 utilizes the thermal energy of the exhaust gas generated after the pyrolysis gas is combusted to heat the primary treatment section 13. The second heat exchanger 32 utilizes the thermal energy of the exhaust gas generated after the pyrolysis gas is combusted to heat the secondary treatment section 15.

[0047] As shown in Fig. 2, a first heat exchanger 31 and a second heat exchanger 32 are installed in the space between the muffle 27 and the outer wall 28. As shown in Figs. 1, 2 and 3, the heat exchanger 31 is disposed near the outer wall 28 of the primary treatment section 13 along the conveying direction of the endless belt 21. The heat exchanger 32 is disposed near the outer wall 28 of the secondary treatment section 15 along the conveying direction of the endless belt 21.

[0048] Heating of the primary treatment section 13 using exhaust gas discharged from the combustion chamber 40 is performed as follows. As shown in Figures 1 and 3, exhaust gas is supplied to the first heat exchanger 31 from a first reheat line 811. The first heat exchanger 31 uses the thermal energy of the exhaust gas supplied from the first reheat line 811 to heat the primary treatment section 13. The exhaust gas that has passed through the first heat exchanger 31 flows through an exhaust pipe 813 and an exhaust pipe 73 in this order, and is supplied to a scrubber 91.

[0049] Heating of the secondary treatment section 15 using the exhaust gas discharged from the combustion chamber 40 is performed as follows. As shown in Figures 1 and 3, exhaust gas is supplied to the second heat exchanger 32 from the second reheat line 821. The second heat exchanger 32 uses the thermal energy of the exhaust gas supplied from the second reheat line 821 to heat the secondary treatment section 15. The exhaust gas that has passed through the second heat exchanger 32 flows through the exhaust pipe 823 and the exhaust pipe 73 in this order, and is supplied to the scrubber 91.

[0050] The first heat exchanger 31 and the second heat exchanger 32 are not particularly limited, but are preferably indirect heat exchangers in that they can suppress corrosion on the outside of the muffle 27 and on the inside of the outer wall 28. The indirect heat exchanger is not particularly limited, but examples thereof include a shell-and-tube heat exchanger, a coiled-tube heat exchanger, and a heated wall.

[0051] The exhaust gas discharged from the combustion chamber 40 may contain fluorine gas, unburned gas, NOx, etc., which may be corrosive. In particular, depending on the type of resin used to seal the solar cell panels, the airflow within the combustion chamber 40, the temperature, and other conditions, unexpected corrosive gases such as fluorine gas, unburned gas, and NOx may remain. If these corrosive gases were supplied directly to the space between the muffle 27 and the outer wall 28, the wall surface could corrode. As a result, complicated maintenance such as replacing and cleaning the entire heating furnace becomes necessary.

[0052] Therefore, an indirect heat exchanger allows two fluids with different temperatures to flow through a space separated by an internal wall. This allows heat to be transferred from the high-temperature fluid to the low-temperature fluid via heat transfer to the wall, heat conduction through the wall, and the wall itself. This allows the primary treatment section 13 and the secondary treatment section 15 to be heated by heat exchange without directly supplying the exhaust gas discharged from the combustion chamber 40 to the space between the muffle 27 and the outer wall 28. Since the exhaust gas passes through the indirect heat exchanger, the effects of corrosive gases can be limited to the indirect heat exchanger itself. If corrosion does occur, the indirect heat exchanger can be selectively replaced. Furthermore, corrosion can be prevented on the exterior of the muffle 27 and the interior of the outer wall 28 of the heating furnace 20. As a result, the indirect heat exchanger facilitates maintenance when affected by corrosive gases.

[0053] In the example shown in Figure 1, etc., the pyrolysis gas supply pipe 61 and the air supply pipe 62 each independently supply pyrolysis gas and air to the combustion chamber 40, but in other examples, the pyrolysis gas and air may be mixed in advance to improve combustion efficiency and reduce corrosive gases, and then the mixed gas may be supplied to the combustion chamber 40.

[0054] When the pyrolysis gas and air are premixed, for example, a parallel pipe for premixing the pyrolysis gas and air may be used instead of the pyrolysis gas supply pipe 61 and the air supply pipe 62 shown in FIG. 1 . The parallel pipe has a pyrolysis gas supply pipe and an air supply pipe arranged at least partially parallel to each other. The parallel pipe has an opening through which the pyrolysis gas and air flow inside, in the portion where the pyrolysis gas supply pipe and the air supply pipe are arranged parallel to each other. Therefore, the pyrolysis gas and air can be premixed and then supplied to the combustion chamber 40. The shape of the parallel pipe is not particularly limited, and examples include a double pipe in which the pyrolysis gas supply pipe and the air supply pipe are arranged concentrically, and a square pipe in which the pyrolysis gas supply pipe and the air supply pipe are arranged side by side.

[0055] Scrubber 91 is disposed downstream of exhaust pipe 71, exhaust pipe 72, exhaust pipe 813, exhaust pipe 823, and exhaust pipe 73. Scrubber 91 is used to remove harmful substances from gases exhausted from each region within continuous heating apparatus 100 before the gases are discharged to the outside.

[0056] The first gas supply means (not shown) supplies an inert gas to the primary processing section 13, the inlet-side sealing chamber 12, and the switching section 14 in the heating furnace 20. Examples of gas sources for the first gas supply means include a membrane separation nitrogen gas generator, an inert gas cylinder, and an inert gas tank. Examples of inert gases include nitrogen gas, argon gas, helium gas, xenon gas, carbon dioxide gas, and superheated steam. From the standpoint of economy, nitrogen gas is preferred.

[0057] The second gas supply means (not shown) supplies an oxygen-containing gas to the secondary processing section 15 in the heating furnace 20 and the outlet-side sealing chamber 18. Examples of the gas supply source for the second gas supply means include an oxygen-containing gas cylinder and an oxygen-containing gas tank. Examples of the oxygen-containing gas include air and oxygen. From the viewpoint of economy, air is preferred.

[0058] (Method for producing heat-treated product) A method for producing heat-treated product 3 using continuous heating apparatus 100 will be described. First, an inert gas is constantly supplied to inlet-side sealing chamber 12 and switching section 14. An oxygen-containing gas is constantly supplied to outlet-side sealing chamber 18. A non-oxidizing atmosphere is prepared in the muffle of primary treatment section 13 by constantly supplying inert gas. An oxidizing atmosphere is prepared in the muffle of secondary treatment section 15 by constantly supplying oxygen-containing gas.

[0059] Examples of the inert gas supplied to the primary treatment section 13 include nitrogen gas, argon gas, helium gas, xenon gas, carbon dioxide gas, superheated steam, etc. From the viewpoint of economy, nitrogen gas is preferred.

[0060] Examples of the oxygen-containing gas supplied to the secondary treatment unit 15 include air and oxygen gas. From the viewpoint of economy, air is preferred.

[0061] Examples of inert gases for sealing supplied into the inlet sealing chamber 12 and the outlet sealing chamber 18 include nitrogen gas, argon gas, helium gas, xenon gas, carbon dioxide gas, and superheated steam. From an economical standpoint, nitrogen gas is preferred. Furthermore, it is preferable that the inert gas be heated, since the amount of gas used can be reduced by volume expansion.

[0062] By driving an exhaust fan (not shown), outside air flowing in from the inlet 11a of the heating furnace 20 is constantly exhausted from the exhaust port 11b together with the inert gas and pyrolysis gas from the inlet-side sealing chamber 12. To prevent the inert gas and pyrolysis gas from inside the heating furnace 20 from leaking out, an opening adjustment plate may be used to adjust the amount of outside air flowing in from the inlet 11a of the heating furnace 20.

[0063] Furthermore, the outside air flowing in from the discharge port 19a of the heating furnace 20 is constantly exhausted from the exhaust port 19b together with the oxygen-containing gas and oxidizing gas from the discharge port-side seal chamber 18. In one example, an opening adjustment plate may be used to adjust the amount of outside air flowing in from the discharge port 19a of the heating furnace 20 in order to prevent the oxygen-containing gas and oxidizing gas from leaking out of the heating furnace 20. The opening of the exhaust port 11b and the exhaust port 19b may be adjusted as necessary.

[0064] The photovoltaic panel 1 is placed on the upstream side of the heating furnace 20 on an endless belt 21 that passes through the heating furnace 20 from the upstream side toward the downstream side of the heating furnace 20. The photovoltaic panel 1 is carried in through the carry-in entrance 11a of the heating furnace 20 by the endless belt 21, and is transported through the heating furnace 20.

[0065] In the entrance-side sealing chamber 12, the photovoltaic cell panel 1 is transported while pushing up the seal curtain 22. If necessary, the opening of the entrance of the entrance-side sealing chamber 12 may be adjusted using an opening adjustment plate.

[0066] In the primary treatment section 13, the solar cell panel 1 is heat-treated in a non-oxidizing atmosphere while being transported, thereby thermally decomposing the resin of the sealing material contained in the solar cell panel 1 to obtain the primary treatment product 2. The oxygen concentration in the primary treatment section 13 is preferably 3.0% by volume or less, more preferably 1.0% by volume or less, and even more preferably 0.1% by volume or less, in order to suppress the formation of detonation gas.

[0067] The ambient temperature in the primary treatment section 13 is set to, for example, 300 to 550°C, and the heating time is set appropriately within a range of, for example, 10 to 180 minutes depending on the heating temperature. The heating temperature may be set in multiple stages. For example, the first stage may be set to 300 to 400°C to decompose and vaporize the acetic acid portion of the EVA, and then the second stage may be set to 400 to 550°C to decompose and vaporize the polyethylene portion, which is the main chain of the EVA. This promotes the decomposition and vaporization of the EVA and suppresses the generation of residues such as char.

[0068] In the switching section 14 , the primary processed material 2 is transported from the primary processing section 13 to the secondary processing section 15 while pushing up the seal curtain 23 .

[0069] In the secondary treatment section 15, the primary treatment product 2 is heat-treated in an oxidizing atmosphere while being transported. This oxidizes carbides of resins such as sealing materials remaining in the primary treatment product 2, resulting in the production of a heat-treated product 3. The oxygen concentration in the secondary treatment section 15 is preferably 80% by volume or less, more preferably 50% by volume or less, and even more preferably 25% by volume or less. Furthermore, in order to promote oxidation of carbides (soot) of resins such as sealing materials remaining in the primary treatment product 2, the oxygen concentration is preferably 5% by volume or more, more preferably 10% by volume or more, and even more preferably 15% by volume or more.

[0070] The ambient temperature in the secondary processing section 15 is set to, for example, 300 to 500° C., and the heating time is set appropriately within the range of, for example, 10 to 180 minutes depending on the heating temperature.

[0071] In the air-cooling chamber 16, the heat-treated object 3 is slowly cooled to prevent cracking of the glass due to rapid cooling. Thereafter, in the cooling chamber 17 to which cooling water is supplied, the heat-treated object 3 is cooled to a temperature at which an operator can handle it, for example, 100°C or less.

[0072] Within the outlet-side sealing chamber 18, the heat-treated object 3 is transported while pushing up the seal curtain 24. If necessary, the opening of the outlet of the outlet-side sealing chamber 18 may be adjusted using an opening adjustment plate. The heat-treated object 3 transported within the heating furnace 20 by the endless belt 21 is discharged from the discharge outlet 19a of the heating furnace 20. The heat-treated object 3 discharged from the heating furnace 20 is mainly a cell, a glass substrate, or the like. Although a small amount of soot may adhere, the amount is reduced to, for example, 100 ppm or less.

[0073] (Mechanism of Action) The continuous heating device 100 described above is equipped with the heating furnace 20 that heat-treats the photovoltaic panels 1 while transporting them to obtain the heat-treated product 3, and therefore the heat-treated product 3 can be obtained by continuously heat-treating the photovoltaic panels 1. Therefore, the processing volume per hour can be increased compared to batch processing.

[0074] The primary treatment section 13 and the secondary treatment section 15 utilize thermal energy generated by combustion of pyrolysis gases that are generated when the sealant of the photovoltaic panel 1 is thermally treated and decomposed in the primary treatment section 13. In particular, the pyrolysis gases generated in the primary treatment section 13 contain more flammable gases than the oxidizing gases generated in the secondary treatment section 15. The continuous heating device 100 can utilize the thermal energy generated by combustion of the pyrolysis gases that are generated in the primary treatment section 13 and contain more flammable gases to assist in heating the primary treatment section 13 and the secondary treatment section 15. More specifically, the pyrolysis gases that are generated when the sealant of the photovoltaic panel is thermally treated and decomposed in the primary treatment section 13 are converted into high-temperature exhaust gases that are generated by a combustion reaction in the combustion chamber 40, and the thermal energy is then utilized in the first heat exchanger 31 and the second heat exchanger 32, respectively.

[0075] According to the continuous heating device 100 having the characteristic configuration described above, the thermal energy generated by the combustion of pyrolysis gas can be used for each heat treatment in the primary treatment section 13 and the secondary treatment section 15, thereby improving the thermal efficiency in the heat treatment of the solar cell panels and reducing the energy costs for heating the primary treatment section 13 and the secondary treatment section 15.

[0076] In addition, according to this embodiment, the thermal efficiency of the heat treatment of the solar cell panel is improved, so the amount of soot adhesion derived from the resin residue can be reduced. In one example, the amount of soot adhesion of the heat-treated product can be reduced to 100 ppm or less. The amount of soot adhesion of the heat-treated product is preferably 70 ppm or less, more preferably 50 ppm or less, and even more preferably 10 ppm or less. The lower limit of the amount of soot adhesion of the heat-treated product is not particularly limited, but may be, for example, 0.1 ppm, 1 ppm, etc.

[0077] 1 , both the primary treatment section 13 and the secondary treatment section 15 utilize thermal energy generated by combustion of pyrolysis gases that are generated when the resin of the photovoltaic panel 1 is decomposed by heat treatment in the primary treatment section 13. However, in other examples of continuous heating devices, either the primary treatment section 13 or the secondary treatment section 15 may utilize thermal energy generated by combustion of pyrolysis gases that are generated when the resin of the photovoltaic panel 1 is decomposed by heat treatment in the primary treatment section 13.

[0078] In the continuous heating apparatus 100, a sealing curtain 22 is suspended in the entrance-side sealing chamber 12, which is upstream of the primary processing section 13 that heats the photovoltaic panels 1. The sealing curtain 22 extends across the transport direction of the photovoltaic panels 1 and hangs down to a length that contacts the endless belt 21. This prevents outside air that has entered the entrance-side sealing chamber 12 and inert gas and pyrolysis gas from the primary processing section 13 from passing through the entrance-side sealing chamber 12. Furthermore, a sealing curtain 24 is suspended in the exit-side sealing chamber 18, which is downstream of the secondary processing section 15. The sealing curtain 24 extends across the transport direction of the heat-treated material 3 and hangs down to a length that contacts the endless belt 21. This prevents outside air that has entered the exit-side sealing chamber 18 and oxygen-containing gas and oxidizing gas from the primary processing section 13 and the cooling chamber 17 from passing through the exit-side sealing chamber 18.

[0079] The seal curtain 22 in the entrance-side sealing chamber 12 is flexible. Therefore, as shown in FIG. 5 , when the photovoltaic panel 1 passes through the entrance-side sealing chamber 12, the seal curtain 22 is pushed up in a bent state. At this time, the seal curtain 22 is pressed against the photovoltaic panel 1 and, as shown in FIGS. 6 and 7 , conforms to the thickness and top surface shape of the photovoltaic panel 1 and comes into close contact with the surface of the photovoltaic panel 1. This minimizes the gap between the seal curtain 22 and the top surface of the photovoltaic panel 1. Therefore, outside air that has entered the entrance-side sealing chamber 12 and inert gases and pyrolysis gases from the primary processing unit 13 are less likely to pass through the entrance-side sealing chamber 12 when the photovoltaic panel 1 passes through it.

[0080] The sealing curtain 23 in the switching section 14 is also flexible. Therefore, for the same reason as the sealing curtain 22, the gap between the sealing curtain 23 and the primary process material 2 is minimized. Therefore, the inert gas and pyrolysis gas from the primary process material 13 that have entered the switching section 14 are unlikely to pass through the switching section 14 and enter the secondary process material 15 when the primary process material 2 passes through the switching section 14. Furthermore, the oxygen-containing gas and pyrolysis gas from the secondary process material 15 that have entered the switching section 14 are unlikely to pass through the switching section 14 and enter the primary process material 13 when the primary process material 2 passes through the switching section 14.

[0081] The sealing curtain 24 in the outlet-side sealing chamber 18 is also flexible. Therefore, for the same reason as the sealing curtain 22, the gap between the sealing curtain 24 and the heat-treatment object 3 is minimized. Therefore, outside air that has entered the outlet-side sealing chamber 18 and oxygen-containing gases and oxidizing gases from the secondary treatment unit 15 and the cooling chamber 17 are less likely to pass through the outlet-side sealing chamber 18 when the heat-treatment object 3 passes through the outlet-side sealing chamber 18.

[0082] In this way, the continuous heating device 100 prevents outside air from entering the primary treatment section 13 and the secondary treatment section 15. Therefore, the oxygen concentration in the primary treatment section 13 is less likely to rise excessively. Furthermore, while maintaining a non-oxidizing atmosphere in the primary treatment section 13, the photovoltaic cell panels 1 can be continuously heat-treated to obtain the heat-treated product 3. As a result, the formation of detonation gas is suppressed. Furthermore, the leakage of inert gas and pyrolysis gas from the heating furnace 20 to the outside is suppressed.

[0083] In the continuous heating apparatus 100 described above, multiple stages of sealing curtains 22 are hung at intervals in the entrance-side sealing chamber 12 in the transport direction of the photovoltaic panel 1, so that outside air that has entered the entrance-side sealing chamber 12 and inert gas and pyrolysis gas from the primary processing unit 13 are less likely to pass further through the entrance-side sealing chamber 12. Also, multiple stages of sealing curtains 24 are hung at intervals in the exit-side sealing chamber 18 in the transport direction of the heat-treatment material 3, so that outside air that has entered the exit-side sealing chamber 18 and oxygen-containing gas and oxidizing gas from the secondary processing unit 15 and cooling chamber 17 are less likely to pass further through the exit-side sealing chamber 18. This sufficiently prevents outside air from entering the primary processing unit 13 and secondary processing unit 15 and oxygen-containing gas and oxidizing gas from leaking from the heating furnace 20.

[0084] In the continuous heating apparatus 100 described above, the seal curtain 22 in the entrance-side sealing chamber 12 is composed of a plurality of strips 22A arranged with no gaps in between in a direction transverse to the transport direction of the photovoltaic panel 1. In other words, the seal curtain 22 is finely divided. Therefore, as shown in Figures 6 and 7 , only a minimum number of strips 22A are pushed up depending on the width of the photovoltaic panel 1 in a direction transverse to the transport direction of the photovoltaic panel 1. This minimizes the difference between the total width of the strips 22A pushed up by the photovoltaic panel 1 and the width of the photovoltaic panel 1, and minimizes the gaps formed between the side surfaces of the photovoltaic panel 1 and the strips 22A on both sides of the photovoltaic panel 1 in a direction transverse to the transport direction of the photovoltaic panel 1. Therefore, outside air that has entered the entrance-side sealing chamber 12 and inert gases and pyrolysis gases from the primary processing unit 13 are less likely to pass further through the entrance-side sealing chamber 12. The sealing curtain 24 in the outlet-side sealing chamber 18 also consists of a plurality of strips (not shown) arranged without gaps in a direction transverse to the conveyance direction of the heat-treated material 3. Therefore, for the same reason as the sealing curtain 22, outside air that has entered the outlet-side sealing chamber 18 and oxygen-containing gas and oxidizing gas from the secondary treatment unit 15 and the cooling chamber 17 are less likely to pass through the outlet-side sealing chamber 18. This sufficiently prevents outside air from entering the primary treatment unit 13 and oxygen-containing gas and oxidizing gas from leaking from the heating furnace 20.

[0085] [Recovery system for components of photovoltaic panels] The recovery system for components of photovoltaic panels includes a continuous heating device and a sorting device that separates glass materials and valuable metal-containing materials from the heat-treated material obtained by the continuous heating device. Details and preferred aspects of the continuous heating device are as described above. Below, an embodiment of the sorting device will be described in detail.

[0086] 8 is a schematic diagram showing an example of a recovery system for components of a photovoltaic panel. The recovery system 200 has a dismantling processing section 211, a heating processing section 231, a sieving processing section 241, a sieving and recovery section 242, a wind sorting section 251, a light product recovery section 252, an air table sorting section 261, a discarded material recovery section 621, a retained material recovery section 622, and a glass recovery section 623.

[0087] The dismantling processing section 211 performs pre-processing such as dismantling the aluminum frame of the solar cell panel and removing the back sheet, terminal box, and cables. The dismantling processing section 211 first removes the aluminum frame, back sheet, terminal box, and cables from the solar cell panel as needed. After that, the internal structure of the solar cell panel is processed sequentially.

[0088] The glass substrate of the solar cell panel is preferably tempered glass, because it can be recovered as fine granular glass after heat treatment and is easy to process with a sorting device. Furthermore, the glass of the solar cell panel before heat treatment may be cracked.

[0089] The heat treatment section 231 produces a heat-treated product by performing heat treatment using the continuous heating apparatus of the present invention. By performing heat treatment using the continuous heating apparatus of the present invention, it is possible to remove the resin of the sealing material of the photovoltaic panel. When the continuous heating apparatus 100 is used, the heat treatment section 231 sequentially performs primary treatment by the primary treatment section 13 and secondary treatment by the secondary treatment section 15. Details and preferred aspects of the primary treatment and secondary treatment have already been described.

[0090] The sieving unit 241 sieves the heat-treated product obtained in the continuous heating device into a first valuable metal-containing material containing cells and copper wires, and a first glass material. By sieving using the sieving unit 241, it is possible to separate the oversized material from the undersized material. The oversized material is collected in the oversized material collection unit 242. The oversized material includes the first valuable metal-containing material containing cells and copper wires. Examples of the oversized material include linear materials such as copper wires, relatively large materials such as cells, and tangled materials thereof.

[0091] The undersieve material is subsequently treated in the air separator 251. The undersieve material may be crushed as necessary before being treated in the air separator 251. The undersieve material includes the first glass material.

[0092] The sieving unit 241 has a sieve. The sieve in the sieving unit 241 may be single-stage or multi-stage. The mesh size of the sieve in the sieving unit 241 is preferably 1 to 100 mm. In the case of a multi-stage sieve, sieving may be performed while changing the mesh size of the sieve in stages. For example, a first sieving unit may use a first sieve with a large mesh size, such as 5 mm or more, 8 mm or more, 10 mm or more, 15 mm or more, or 20 mm or more, and a second sieving unit may use a second sieve with a smaller mesh size than the first sieve, such as 15 mm or less, 10 mm or less, 8 mm or less, 5 mm or less, or 3 mm or less. The difference in mesh size between the first sieve and the second sieve may be 1 mm or more, 3 mm or more, 5 mm or more, or the like.

[0093] The upper limit of the sieve opening size may be 80 mm or less, or 60 mm or less. The shape of the openings of the sieve used for sieving may be circular or polygonal. A sieve sorter may also be used.

[0094] The air sorting unit 251 separates the first glass material sieved in the sieving unit 241 into a second valuable metal-containing material containing cells and a second glass material by air sorting. The second valuable metal-containing material containing cells is recovered as a light product in the light product recovery unit 252. The second glass material is treated as a heavy product in the subsequent air table sorting unit 261.

[0095] Wind sorting is one of the gravity sorting techniques. Gravity sorting is a sorting technique that separates target substances by taking advantage of the difference in specific gravity between the target substance and other substances. Wind sorting equipment can be used, including vertical wind sorters, zigzag sorters, horizontal flow sorters, inertial force linear sorters, and inertial force curved sorters.

[0096] For example, a vertical wind power sorter such as that shown in Figure 9 of Japanese Patent Application Laid-Open No. 2023-89446 may be used. With a vertical wind power sorter, by blowing an upward flow into a vertical column from below, particles with low specific gravity and low settling velocity can be moved upward and recovered as light products, and particles with high specific gravity and high settling velocity can be moved downward and recovered as heavy products.

[0097] Light products in wind sorting include solar cell panels. Heavy products in wind sorting include concentrates of coarse glass from solar cell panels. With isotropic glass particles derived from cover glass, small particles tend to be distributed to the light product. On the other hand, cells are flat particles that are thought to be more susceptible to airflow over a wide area, so larger particles tend to be distributed to the light product. Since larger particles are easier to separate into light and heavy products, there is less need to crush them excessively before wind sorting. Metals can be recycled by metal refining the second valuable metal-containing material, including the light product cells.

[0098] The wind speed in wind sorting can be, for example, 4 to 15 m / s, and the air volume can be 20 to 70 L / min. An example of a device suitable for wind sorting is the wind sorter L750SRM model manufactured by Harada Corporation.

[0099] The air table sorting unit 261 uses an air table to separate the third glass material from the second glass material, which is a heavy product obtained in the air sorting unit 251. The air table sorting unit 261 can separate the third glass material into (i) a third glass material containing high-purity glass, (ii) retained light products such as single-edged products containing low-purity glass and the like, and copper wire-derived products, and (iii) discharged light products such as copper wire-derived products and cell-derived products.

[0100] The air table sorting section 261 recovers the valuable metal-containing materials in the discharged material recovery section 621 and the retained material recovery section 622. The third glass material is recovered in the glass recovery section 623.

[0101] The air table sorting section 261 may use, for example, a single-axis air table sorter such as that shown in FIG. 10 of Patent Document 1. This air table sorter vibrates a deck slightly angled from the horizontal and blows air perpendicular to the deck from below. High-specific-gravity particles move downward in the powder bed without being significantly affected by the wind and concentrate near the peaks on the deck surface. While their downward movement is suppressed by the peaks, they move upward due to the deck vibration and are collected as heavy products. On the other hand, low-specific-gravity particles move upward in the powder bed due to the wind and move downward along the slope of the deck and are collected as light products.

[0102] In air table sorting, materials can be classified into multiple categories, such as those discharged from the air table's discharge port and those remaining on the air table. Taking the air table shown in FIG. 10 of Patent Document 1 as an example, light products, primarily copper wire and cells, are discharged from the bottom of the deck. Heavy products, primarily glass, are discharged from the top of the deck. Materials that are difficult to move in either direction during air table operation may be collected as retained material remaining on the air table's deck. Light products, such as copper wire, are separated from the retained material above the powder layer.

[0103] An example of an air table is the SRM 296P-72N air table manufactured by Harada Corporation. To separate light products and heavy products with higher precision, further sorting may be performed using air sorting, air table sorting, sieving, or the like.

[0104] According to the recovery system for solar cell panel components of the present invention, the glass purity of the third glass material after sorting can be set to 99.99% or higher. The glass purity of the third glass material after sorting is preferably 99.995% or higher, more preferably 99.999% or higher, and even more preferably 99.9995% or higher. The upper limit of the glass purity of the third glass material after sorting is not particularly limited, but may be, for example, 99.9999%, 99.9998%, etc.

[0105] The recycling rate of the glass material contained in the heat-treated product is preferably 85% or more, more preferably 90% or more, and even more preferably 93% or more. The recycling rate of the glass material contained in the heat-treated product is calculated using the following formula: Recycling rate of the glass material contained in the heat-treated product = weight of recycled glass material / weight of glass material contained in the heat-treated product

[0106] The copper wire contained in the heat-treated product can be recycled by metal refining of the first valuable metal-containing material. The recycling rate of the copper wire is preferably 90% or more, more preferably 95% or more, and even more preferably 99% or more. The recycling rate of the copper wire contained in the heat-treated product is calculated using the following formula: Recycling rate of the copper wire contained in the heat-treated product = weight of recycled copper wire / weight of copper wire contained in the heat-treated product

[0107] The cells contained in the heat-treated product can be recycled by metal refining of the first valuable metal-containing material and the second valuable metal-containing material. The cell recycling rate is preferably 90% or more, more preferably 95% or more, and even more preferably 99% or more. The recycling rate of the cells contained in the heat-treated product is calculated using the following formula: Recycling rate of cells contained in the heat-treated product = weight of recycled cells / weight of cells contained in the heat-treated product

[0108] Although several embodiments have been described above, the present invention is not limited to the exemplary embodiments disclosed in this specification and can be appropriately modified and implemented without departing from the spirit of the invention. The embodiments disclosed in this specification can be implemented in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention.

[0109] For example, Fig. 9 is a schematic diagram showing another example of a recovery system for components of a photovoltaic panel. Recovery system 201 is a modified example of recovery system 200 shown in Fig. 8. As in recovery system 201, the order of dismantling processing section 211 and heating processing section 231 may be reversed. In other words, dismantling processing may be performed after heating processing using the continuous heating device of the present invention. Resin from back sheets, terminal boxes, etc. is removed by heating processing.

[0110] Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to the following description.

[0111] Example 1 A photovoltaic panel was treated using a continuous heating device 100 to obtain a heat-treated product. The aluminum frame was then removed. In the primary treatment, the panel was heated in a nitrogen gas atmosphere from room temperature to 500°C for 7 minutes, and then at 500°C for 16 minutes. The oxygen concentration in the primary treatment section 13 was controlled to 3% by volume. In the secondary treatment, the panel was heated in an oxidizing atmosphere at 500°C for 16 minutes. The oxygen concentration in the secondary treatment section 15 was controlled to 21% by volume. Next, 273.6 kg of the heat-treated product (3.4 kg of copper wire, 13 kg of cells, and 255.5 kg of glass material) was sorted using the recovery system 200 shown in FIG. 8. As a result of the sorting process, 17 kg of a first valuable metal-containing material containing 62.6% copper wire and cells (the remainder was glass), 14.7 kg of a second valuable metal-containing material containing 39.3% cells (the remainder was glass), and 239.5 kg of a third glass material with a purity of 99.9997% (the remainder was cells) were recovered. The recycling rates were 100% for copper wire, 99.5% for cells, and 93.7% for glass material, respectively.

[0112] Comparative Example 1 A photovoltaic panel was heat-treated in the continuous heating device 100 under the same conditions as in Example 1, except that the heat treatment was carried out only by the primary treatment unit 13 without operating the secondary treatment unit 15 .

[0113] As can be seen by comparing FIGS. 10 and 11, the amount of soot adhering to the glass fragments in Example 1 was less than that in Comparative Example 1.

[0114] According to the present invention, the thermal efficiency in the heat treatment of photovoltaic panels is improved, energy costs can be reduced, and the quality of valuable materials recovered from photovoltaic panels is improved.

[0115] REFERENCE SIGNS LIST 1 Photovoltaic cell panel 2 Primary treatment material 3 Heat treatment material 13 Primary treatment unit 14 Switching unit 15 Secondary treatment unit 20 Heating furnace 21 Endless belt

Claims

1. A continuous heating device comprising a heating furnace for obtaining a heat-treated product by heat-treating a solar cell panel while conveying it with an endless belt, wherein the heating furnace has a primary treatment section for obtaining a primary treated product by heat-treating the solar cell panel in a non-oxidizing atmosphere while conveying it with the endless belt, and a secondary treatment section for obtaining the heat-treated product by heat-treating the primary treated product in an oxidizing atmosphere while conveying it with the endless belt, and at least one of the primary treatment section and the secondary treatment section utilizes heat energy generated by combustion of pyrolysis gas generated when the sealing material of the solar cell panel is decomposed by heat treatment in the primary treatment section.

2. The continuous heating device according to claim 1, wherein a flexible seal curtain that crosses the conveying direction of the solar cell panel and contacts the endless belt is suspended in at least one place in the heating furnace.

3. The continuous heating device according to claim 2, wherein the seal curtain is suspended in the heating furnace between the primary treatment section and the secondary treatment section.

4. The continuous heating device according to claim 2, wherein the seal curtain is suspended in the heating furnace upstream of the primary treatment section.

5. The continuous heating device according to claim 2, wherein the seal curtain is suspended in the heating furnace downstream of the secondary treatment section.

6. The continuous heating device according to claim 1, wherein at least one of the primary treatment section and the secondary treatment section utilizes heat energy of exhaust gas generated after burning the pyrolysis gas.

7. The continuous heating device according to claim 1, further comprising a combustion chamber for burning the pyrolysis gas generated when the sealing material of the solar cell panel is decomposed by heat treatment in the primary treatment section.

8. The continuous heating device according to claim 7, wherein at least one of the primary treatment section and the secondary treatment section utilizes heat energy of the exhaust gas discharged from the combustion chamber.

9. The continuous heating device according to claim 1, wherein a heat exchanger that utilizes heat energy generated by combustion of the pyrolysis gas is disposed in at least one of the primary treatment section and the secondary treatment section.

10. The continuous heating device according to claim 9, wherein the heat exchanger utilizes heat energy of the exhaust gas generated after burning the pyrolysis gas.

11. The heating furnace has a muffle that surrounds and covers the endless belt, and an outer wall that surrounds and covers the muffle, and the heat exchanger is disposed in a space between the muffle and the outer wall. The continuous heating device according to claim 9.

12. The continuous heating device according to claim 9, wherein the heat exchanger is an indirect heat exchanger.

13. The continuous heating device according to claim 11, wherein an electric heater is disposed in a space between the muffle and the outer wall.

14. The continuous heating device according to claim 1, wherein the amount of soot adhesion on the object to be heat-treated is 100 ppm or less.

15. A recovery system for components of a solar cell panel, comprising the continuous heating device according to any one of claims 1 to 14, and a sorting device that sorts glass materials and valuable metal-containing substances from the object to be heat-treated.

16. The recovery system for components of a solar cell panel according to claim 15, wherein the sorting device has a screening unit that screens the object to be heat-treated into a first valuable metal-containing substance including cells and copper wires, and a first glass material.

17. The recovery system for components of a solar cell panel according to claim 16, wherein the sorting device further has a pneumatic separation unit that pneumatically separates the first glass material screened by the screening unit into a second valuable metal-containing substance including cells and a second glass material.

18. The recovery system for components of a solar cell panel according to claim 17, further comprising an air table sorting unit that uses an air table to sort a third glass material from the second glass material.

19. The recovery system for components of a solar cell panel according to claim 18, wherein the glass purity of the sorted third glass material is 99.99% or more.

20. The recovery system for components of a solar cell panel according to claim 15, wherein the recycling rate of the glass material contained in the object to be heat-treated is 85% or more.

21. The recovery system for components of a solar cell panel according to claim 15, wherein the recycling rate of the cells contained in the object to be heat-treated is 90% or more.

22. The recovery system for components of a solar cell panel according to claim 15, wherein the recycling rate of the copper wires contained in the object to be heat-treated is 90% or more.

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