Support for photovoltaic modules for treating the modules in a pyrolysis furnace

Abstract

The invention relates to a support (500) for photovoltaic modules (100), the support being intended to enter a pyrolysis furnace, and the support comprising: - a loading compartment (510), formed by a plurality of frames (511) creating spaces (512) between them, and allowing at least one photovoltaic module (100) to be held in each space (512); - a receptacle (520) comprising: * a tank having side walls (521), a bottom (522) and a main opening (523), the tank being intended to collect fragments of mineral materials from the photovoltaic modules once pyrolysis has been applied, the side walls being provided with secondary openings (524) to allow the gases present in the pyrolysis furnace to circulate; * support regions at the main opening to support the loading compartment (510) when it is arranged over the tank.

Description

Support for photovoltaic modules for the treatment of said modules in a pyrolysis oven FIELD OF INVENTION

[0001] The present invention relates to the field of photovoltaic module recycling. It relates in particular to a support for photovoltaic modules enabling the treatment of said modules in a pyrolysis furnace, for the thermal dismantling of the modules with a view to recycling the materials from which they are made. TECHNOLOGICAL BACKGROUND OF THE INVENTION

[0002] Given the exponential increase in photovoltaic panels produced and installed, their recycling becomes essential to recover and valorize the precious materials that compose them (metals, glass, silicon...) ().

[0003] In a recycling process, the metal frame 110 (“frame”) of the end-of-life panels 200 and the junction box 150 are first separated from the photovoltaic module 100, which corresponds to the sandwich of functional layers, generally including a stack of glass 120, polymer layers 131,132,133 and photovoltaic cells 140 with semiconductor and metallic contacts.

[0004] It is then known that the photovoltaic module 100 can be dismantled either by a mechanical process or by thermal treatment based on a pyrolysis or combustion process. Tunnel furnaces (continuous processing, combustion process) or batch furnaces (batch processing, pyrolysis or combustion process) can be used. The polymer layers 131, 132, 133, contained within the functional layer sandwich (photovoltaic module 100), are formed of organic compounds, which are decomposed by pyrolysis or burned by combustion, thus separating the layers into mineral materials of the sandwich.

[0005] The effectiveness of the thermal dismantling process necessarily depends on the design of the support used to support the 100 photovoltaic modules from the loading into the furnace until unloading at the end of the treatment. SUBJECT OF THE INVENTION

[0006] The present invention provides a support for photovoltaic modules adapted for processing said modules, particularly in a pyrolysis oven. The design of the support allows for excellent pyrolysis efficiency and very high-quality mineral material (from the modules) to be broken down into fragments. BRIEF DESCRIPTION OF THE INVENTION

[0007] The invention relates to a support for photovoltaic modules, intended to be inserted into a pyrolysis oven, comprising:

[0008] - a loading compartment, formed by a plurality of frames creating spaces between them, and allowing at least one photovoltaic module to be held in each space,

[0009] - a receptacle containing:

[0010] * a tank having side walls, a bottom and a main opening, the tank being intended to collect fragments of mineral matter from photovoltaic modules after pyrolysis, the side walls being fitted with secondary openings to allow the circulation of gases present in the pyrolysis furnace,

[0011] * Support areas at the main opening to support the loading compartment when positioned above the tank.

[0012] According to other advantageous and non-limiting features of the invention, taken alone or in any technically feasible combination: the support areas are provided by horizontal bars connecting two opposite sides of the main opening or by a horizontal grid covering the main opening; the tank has inclined inner walls which meet to form a gable roof, said inner walls having diffusers putting the inside and outside of the tank into fluidic communication, the bottom of the tank not extending below the gable roof; the diffusers provide staggered openings to prevent the passage of fragments of mineral matter to the outside of the tank; the gable roof rises at least to half the height of the side walls; the support is formed from a ferrous alloy or 304 stainless steel;The receptacle has a hinged discharge door, attached to a side wall of the tank and capable of opening when the tank is positioned on an inclined plane; the receptacle has a hinged discharge door, attached to the bottom of the tank and capable of opening when the tank is positioned above a container for recovering mineral material fragments; the loading compartment is configured to hold the flat photovoltaic modules in a horizontal position, along a horizontal plane; the loading compartment is configured to hold the flat photovoltaic modules in a vertical position, along a vertical plane; the loading compartment has two longitudinal edges parallel to the vertical longitudinal plane, and it includes two guide panels, each arranged along a longitudinal edge, inclined outwards with respect to the vertical longitudinal plane at an angle between 10° and 45°;Each guide panel has a height greater than or equal to one third of a vertical dimension of the photovoltaic modules when loaded into the loading compartment, or a height greater than or equal to one third of a height along a vertical axis of the loading compartment; the loading compartment is removable and can be separated from the receptacle; the support includes a cover configured to close the main opening and the secondary openings of the receptacle tank. BRIEF DESCRIPTION OF THE FIGURES

[0013] Other features and advantages of the invention will become apparent from the detailed description of the invention which follows with reference to the accompanying figures in which:

[0014] This presents an exploded view of a photovoltaic panel;

[0015] Presents fragments of mineral materials obtained from the pyrolysis of photovoltaic modules, (A) according to a prior art process, (B) with a pyrolysis process using a support according to the present invention;

[0016] Presents a photo of a support for photovoltaic modules according to a first embodiment of the invention;

[0017] Presents a cross-sectional view, along a plane (x,z), of a support for photovoltaic modules conforming to the first embodiment of the invention;

[0018] This presents a photo of a support for photovoltaic modules according to a second embodiment of the invention;

[0019] Presents a cross-sectional view, along a plane (x,z), of a support for photovoltaic modules conforming to the second embodiment of the invention;

[0020] This presents a side view, along a plane (y,z), of a support receptacle for photovoltaic modules according to the invention;

[0021] Presents a perspective view of a hooded receptacle for supporting photovoltaic modules according to the invention;

[0022] This presents a schematic view of a batch pyrolysis oven, using a photovoltaic module support according to the invention.

[0023] Some figures are schematic representations which, for the sake of readability, are not necessarily to scale or in which certain details are omitted. DETAILED DESCRIPTION OF THE INVENTION

[0024] The present invention relates to a support 500 for photovoltaic modules 100, intended to enter a furnace 1 in order to apply a pyrolysis treatment to said modules 100. This pyrolysis is implemented to dismantle the modules 100 with a view to recycling the mineral materials (glass, silicon, metals) which compose them.

[0025] The quality of the mineral materials recovered after pyrolysis is crucial for the profitability of a 100% photovoltaic module recycling process. This quality depends on the complete degradation of the polymer layers into inorganic matter (gases and carbonaceous residues) and the complete oxidation of the carbonaceous residues into gases. Furthermore, the heat treatment time should be as short as possible for obvious economic reasons.

[0026] Loading a pallet of 100 photovoltaic modules, stacked one on top of the other, results in a very slow and substandard processing of the modules in the pyrolysis furnace. As an illustration, Figure (A) shows a photograph of mineral material fragments resulting from pyrolysis in the aforementioned configuration: the glass fragments are relatively opaque due to the presence of brownish deposits (carbon residues); and pieces of carbon residue are present among the glass fragments, silicon, and aluminum wires. This complicates the sorting of the materials and affects the quality of their recycling.

[0027] La(B) presents a photo of fragments of mineral materials from a pyrolysis carried out using the support 500 for photovoltaic modules 100 according to the present invention: the fragments of glass, cells (silicon and silver contact) and aluminium are of good quality and no carbon residue is present.

[0028] To achieve such a result, the 500 support for 100 photovoltaic modules has been specifically optimized to: allow efficient and rapid heat transfer from enclosure 2 of pyrolysis furnace 1 to the 100 photovoltaic modules, ensuring good gas and / or air circulation between said 100 modules; maintain an aerated architecture even after polymer decomposition to promote the kinetics of pyrolysis and then oxidation reactions; allow complete oxidation of carbon residues by providing air circulation at the end of the pyrolysis cycle; improve the cooling rate, to best limit the treatment time.

[0029] Because it is intended to withstand temperatures exceeding 500°C, the 500 support is made from any material that provides mechanical resistance at such temperatures. Preferably, it is manufactured from a ferrous alloy, particularly 304 stainless steel.

[0030] The support 500 according to the invention comprises a loading compartment 510, formed by a plurality of frames 511 providing spaces 512 between them, and allowing at least one photovoltaic module 100 to be held in each space 512. Each module 100 is thus held in a fully deployed state, i.e., flat, not folded upon itself.

[0031] As an example, two or three 100 modules can be arranged in the same 512 space; however, it remains advantageous for only one 100 photovoltaic module to be positioned in each 512 space.

[0032] Typically, the 512 spaces have a width (interval between two 511 frames, along the x-axis in Figures 3a and 3b, and along the z-axis in Figures 4a and 4b) of between 0.5 cm and 5 cm, for example 2 cm.

[0033] Typically, a 100 photovoltaic module is rectangular, its length is between 1 m and 2.5 m, its width is between 0.8 m and 1.5 m, and its thickness can vary between 2 mm and a few cm.

[0034] According to a first embodiment, illustrated in Figures 3a and 3b, each photovoltaic module 100 is positioned substantially vertically along a plane (y,z). The charging compartment 510 has two longitudinal edges parallel to the vertical longitudinal plane (y,z) and two lateral edges parallel to the vertical lateral plane (x,z). The longitudinal and lateral edges are not solid but are largely perforated. For example, as illustrated in Figure 3a, the longitudinal edges consist solely of metal bars 511a connecting the frames 511. Each frame 511 of the compartment 510 can be similarly stiffened by metal bars connecting two opposite sides of said frame 511.

[0035] The height of compartment 510 (along the z-axis in the figures) is preferably equal to or greater than the vertical dimension of modules 100 when loaded into spaces 512.

[0036] Advantageously, in this first embodiment, the loading compartment 510 comprises two guide panels 513, each arranged along a longitudinal edge. Each guide panel 513 is inclined outwards and upwards, forming an angle α between 10° and 45° with respect to the vertical longitudinal plane (y,z). These panels 513 guide the dislocated module pieces into the receptacle 520, which will be described later, and prevent any pieces from scattering in the furnace 1 in the event of a sudden dislocation or rebound off the metal structure.

[0037] Advantageously, each guide panel 513 has a height greater than or equal to one-third, or even half, of the vertical dimension of the photovoltaic modules 100 when loaded into the loading compartment 510 (in the example above, the vertical dimension considered is the width of the modules 100). In other words, each guide panel 513 can extend to a height of approximately one-third, or even half, of the height (along the vertical z-axis) of the loading compartment 510.

[0038] According to a second embodiment, illustrated in Figures 4a and 4b, each photovoltaic module 100 is positioned approximately horizontally, along a plane (x,y). The charging compartment 510 has two longitudinal edges parallel to the vertical longitudinal plane (y,z) and two lateral edges parallel to the vertical lateral plane (x,z).

[0039] The structure of compartment 510 can be similar to that described in the first embodiment, except that it is tilted 90° to provide horizontal rather than vertical support for the modules 100. In this second embodiment, the height of compartment 510 (along the z-axis) is defined by the number of frames 511 (and therefore loading spaces 512) provided.

[0040] Regardless of the embodiment, the loading compartment 510, with its ventilated structure, ensures separation between the photovoltaic modules 100 and excellent circulation of the gaseous atmosphere when the support 500 is within the pyrolysis oven 1.

[0041] The 500 support also includes a 520 receptacle, to collect the pieces of the 100 modules when they break apart during the pyrolysis heat treatment.

[0042] This receptacle 520 comprises a tank having side walls 521, a bottom 522 and a main opening 523. The tank is intended to collect fragments of mineral material from photovoltaic modules 100 after dismantling by pyrolysis.

[0043] The receptacle 520 also includes support areas 523a at the main opening 523 to support the loading compartment 510 when it is positioned above the tank.

[0044] The support areas 523a can be provided by horizontal bars connecting two opposite sides of the main opening 523 ( ) or by a horizontal grid 527 covering the main opening 523 (not shown). The mesh of the grid 527 is defined so that the fragments resulting from the dislocation of the modules 100, and having a given lateral dimension, fall into the tank. The grid 527 may, for example, have holes with diameters (or lateral dimensions) ranging from 5 mm to 20 mm.

[0045] If it does not serve as a support zone for the loading compartment 510, the horizontal grid 527 can alternatively be placed below the support zones 523a, at a given height within the tank (). Note that another grid 528 can be used below the horizontal grid 527, lower down in the receptacle tank 520. It preferably has smaller holes than the horizontal grid 527, typically on the order of 0.5 mm to 1 mm. These grids 527 and 528 allow for sieving and promote efficient circulation of the gaseous atmosphere around the fragments by creating layers of fragments more readily exposed to the atmosphere than in the case of a single pile of fragments at the bottom of the tank.

[0046] The side walls 521 of the tank are advantageously provided with secondary openings 524 to allow the circulation of gases within the receptacle 520 during the pyrolysis heat treatment. The secondary openings 524 are typically located in the upper third of the walls 521.

[0047] Also advantageously, the receptacle 520 has inclined inner walls 525a, 525b, which meet to form a gable roof 525 in the interior space of the tank (,). The gable roof 525 preferably extends at least halfway up the side walls 521. The inner walls 525a, 525b have diffusers 5251 that establish fluidic communication between the interior of the tank and the exterior (ambient atmosphere or gaseous atmosphere within the furnace enclosure 1). Several diffusers 5251 can be arranged on each inner wall 525a,525b, to maximize the circulation of the gaseous atmosphere of the furnace 1 within the receptacle 520. The inner walls 525a,525b therefore have an internal surface, oriented towards the interior of the receptacle, and an external surface which directly sees the atmosphere of the enclosure of the furnace 1.

[0048] To achieve this, the bottom 522 of the tank does not extend under the gable roof 525; it stops against (and is integral with) the lower edge of each of the inner walls 525a, 525b, the upper edges of said walls 525a, 525b meeting at the apex of the roof 525. The lower and upper edges of the walls 525a, 525b extend along the y-axis. The fact that the bottom 522 of the tank is "open" under the gable roof 525 promotes efficient circulation of hot gases throughout the entire receptacle.

[0049] The 5251 diffusers preferentially provide baffled openings, to prevent fragments of dislocated 100 modules from passing outside the tank.

[0050] The receptacle 520 is advantageously equipped with a discharge door 526. This door 526 is preferably hinged and can be either integral with a side wall 521 of the tank ( ) or integral with the bottom 522 of the tank (not shown). In the first case, external actuation of the door 526 allows it to be opened; alternatively, it can be configured to open when unlocked and the tank is positioned on an inclined plane, due to the pressure of the mineral fragments contained in the tank, which flow by gravity towards a recovery container. In the second case, unlocking the discharge door, when the tank is positioned above the recovery container, leads to its opening and the fragments falling into the container.

[0051] In the support 500 according to the invention, it is advantageous that the loading compartment 510 is removable and can be separated from the receptacle 520. Indeed, at the end of the pyrolysis thermal treatment, the loading compartment 510 is empty and the step of recovering the fragments contained in the receptacle 520 is made much more ergonomic by the removal of said compartment 510.

[0052] The fragments of mineral materials can have lateral dimensions on the order of centimeters, millimeters, or even smaller, which can correspond to very fine particles capable of generating dust when the receptacle 520 is transported and during the unloading of its contents into the recovery container. Therefore, the support 500 can include a cover 530, configured to seal the main opening 523 and the secondary openings 524 of the tank, in the absence of the loading compartment 510. The receptacle 520, thus covered, can be stored or transported to a subsequent stage with a minimal risk of particulate contamination of the plant. Furthermore, the dust raised by the flow of fragments during transfer to the recovery container is contained within the internal space of the tank.

[0053] The support 500 according to the present invention can, for example, be used in a pyrolysis oven 1 for batch processing, as illustrated in the figure. The loading compartment 510, arranged on the receptacle 520, is first filled with photovoltaic modules 100 to be recycled, comprising (as mentioned in the introduction) a stack of glass 120, polymer layers 131, 132, 133, and photovoltaic cells 140 with semiconductor and metallic contacts. Each module 100 is positioned in a space 512 defined between two frames 511 of the loading compartment 510. The module 100 is kept flat; it is not folded over itself, which will greatly promote heat diffusion over its entire surface during the heat treatment.

[0054] Before mounting them on the support 500, it is advantageous to break the glass layer 120 of the photovoltaic modules 100. This layer, being made of tempered glass, fractures into small, non-cutting pieces a few millimeters in size upon impact. However, due to the presence of polymer layers 131, 132, and 133, each module 100 retains its intact form, typically a rectangle from 1 to several meters in size. 2 , and can be easily placed on support 500. This pre-fracturing of the glass layer 120 allows the recovery, at the end of pyrolysis treatment (i.e. when all polymer layers have been decomposed), of fragments of mineral materials (glass, semiconductor, metals), which are easier to sort and handle than large-dimension layers.

[0055] The support 500, including the loading compartment 510 holding the modules 100 and the receptacle 520, is introduced into chamber 2 of the pyrolysis furnace 1 via a sealed door 25. When the sealed door 25 is closed, the temperature inside chamber 2 is raised, by means of heating means 41 (for example, one or more burners), to the pyrolysis temperature. This temperature is typically between 400°C and 600°C. Pyrolysis takes place with little or no oxygen in the gaseous atmosphere of chamber 2 (typically less than 5% oxygen, or even less than 4%, or even less than 3%). The polymer decomposition kinetics are enhanced by the excellent gas circulation between the modules 100, which ensures rapid heat diffusion. A stratified dislocation of the modulus 100, linked to the decomposition of polymer layers, occurs during pyrolysis.The glass layer 120 being previously broken, fragments of glass fall onto the grid, onto the two-sided roof 525 and / or onto the bottom 522 of the tank, and the cell layer (silicon and contact) also breaks into pieces due to its fall.

[0056] The pyrolysis gases, resulting from the decomposition of polymers, are burned in a post-combustion chamber 3, maintained at a temperature greater than or equal to 850°C (according to the standards imposed), by heating means 42,43 which may be burners, supplied with commercial combustion gas (natural gas, LPG) and an oxidant (for example air).

[0057] Once the polymers have decomposed and all (or a large majority) of the pyrolysis gases have been generated and burned in the afterburner chamber 3, an oxidation step at a temperature typically between 500°C and 800°C is carried out in chamber 2 of the pyrolysis furnace 1, under an oxidizing atmosphere (for example, an oxygen content in the gaseous atmosphere of furnace 1 greater than or equal to 5%). This step removes carbon residues and is most effective when the fragments of the dislodged modules are brought into contact with the oxidizing atmosphere.

[0058] The furnace temperature is then lowered (for example, to the range of 150°C–300°C) to allow the removal of the support 500. The empty loading compartment 510 is separated from the receptacle 520 containing the mineral material fragments and can be placed on another empty receptacle to be refilled with modules 100. The receptacle 520, whose chamber is filled with fragments, is advantageously covered before being transported to the recovery container and emptied into it. Preferably, the horizontal grid 527 or other grid 528, if present, is also removed from the chamber before the receptacle 520 is covered.

[0059] The 500 support has been described above in a particular mode of implementation, but could be used in other types of pyrolysis ovens, and according to different heat treatment sequences.

[0060] Of course, the invention is not limited to the embodiments and examples described, and alternative embodiments can be made without departing from the scope of the invention.

Claims

Support (500) for photovoltaic modules (100), intended to fit into a pyrolysis oven (1), comprising: - a loading compartment (510), formed of a plurality of frames (511) providing spaces (512) between them, and allowing at least one photovoltaic module (100) to be held in each space (512), - a receptacle (520) comprising: * a tank having side walls (521), a bottom (522) and a main opening (523), the tank being intended to collect fragments of mineral matter from the photovoltaic modules (100) after the application of pyrolysis, the side walls (521) being provided with secondary openings (524) to allow the circulation of gases present in the pyrolysis oven (1), the tank further comprising inclined inner walls (525a, 525b), which meet to form a gable roof (525),said inner walls comprising diffusers (5251) providing fluidic communication between the interior and exterior of the tank, the bottom (522) of the tank not extending under the gable roof (525),* support areas (523a) at the main opening (523) to support the loading compartment (510) when it is positioned above the tank. Support (500) for photovoltaic modules (100) according to the preceding claim, wherein the support areas (523a) are provided by horizontal bars connecting two opposite sides of the main opening (523) or by a horizontal grid covering the main opening (523). Support (500) for photovoltaic modules (100) according to any one of the preceding claims, wherein the diffusers (5251) provide baffled openings, to prevent the passage of fragments of mineral matter to the outside of the tank. Support (500) for photovoltaic modules (100) according to any one of the preceding claims, wherein the gable roof (525) rises at least to half the height of the side walls (521). Support (500) for photovoltaic modules (100) according to any one of the preceding claims, formed from a ferrous alloy or 304 stainless steel. Support (500) for photovoltaic modules (100) according to any one of the preceding claims, wherein the receptacle (520) has a hinged drain door (526), ​​attached to a side wall (521) of the tank and capable of opening when the tank is positioned on an inclined plane. Support (500) for photovoltaic modules (100) according to any one of claims 1 to 5, wherein the receptacle (520) has a hinged drain door, integral with the bottom (522) of the tank and capable of opening when the tank is positioned over a container for recovering fragments of mineral materials. Support (500) for photovoltaic modules (100) according to any one of the preceding claims, wherein the loading compartment (510) is configured to hold the flat photovoltaic modules (100) in a horizontal position, along a horizontal plane (x,y). Support (500) for photovoltaic modules (100) according to any one of claims 1 to 7, wherein the loading compartment (510) is configured to hold the flat photovoltaic modules (100) in a vertical position, along a vertical plane (y,z). Support (500) for photovoltaic modules (100) according to the preceding claim, wherein the loading compartment (510) has two longitudinal edges parallel to the vertical longitudinal plane (y,z), and it includes two guide panels (513), each disposed along a longitudinal edge, inclined outwards with respect to the vertical longitudinal plane (y,z) at an angle between 10° and 45°. Support (500) for photovoltaic modules (100) according to the preceding claim, wherein each guide panel (513) has a height greater than or equal to one third of a height along a vertical axis (z) of the loading compartment (510). Support (500) for photovoltaic modules (100) according to any one of the preceding claims, wherein the charging compartment (510) is removable and can be separated from the receptacle (520). Support (500) for photovoltaic modules (100) according to the preceding claim, comprising a hood (530) configured to close the main opening (523) and the secondary openings (524) of the receptacle tank (520).

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