Pyrolysis method for breaking down photovoltaic modules

Abstract

The invention relates to a pyrolysis furnace (1) for recycling photovoltaic modules (100), comprising: at least one pyrolysis enclosure (2) for receiving the photovoltaic modules (100), a post-combustion chamber (3) fluidically connected to the pyrolysis enclosure (2), first heating means (41) for the pyrolysis enclosure (2) and second heating means (42, 43) for the post-combustion chamber (3), a neutral gas distribution system (6) designed to inject said neutral gas into the pyrolysis enclosure (2), a temperature sensor (31) arranged in the post-combustion chamber (30 for measuring a temperature at the core of said chamber, referred to as the central temperature (Tc), a controller (C) designed to control the injection of neutral gas by the distribution system (6) on the basis of the central temperature (Tc). The invention further relates to a pyrolysis method with optimised post-combustion loading.

Description

Pyrolysis process for dismantling photovoltaic modules FIELD OF INVENTION

[0001] The present invention relates to the field of photovoltaic module recycling. It relates in particular to a process using a batch pyrolysis furnace, particularly suitable for the thermal dismantling of photovoltaic modules for the purpose of 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 photovoltaic panels 200 and the junction box 150 are first separated from the photovoltaic module 100, which is a sandwich of functional layers, generally including a stack of glass 120, polymer layers 131, 132, 133 and photovoltaic cells 140 with semiconductor and metal contacts (). The polymer layers may include, in particular, ethylene vinyl acetate (EVA), polyethylene terephthalate (PET), polyvinyl fluoride (PVF) or polyvinylidene fluoride (PVDF).

[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 and / 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 sandwich of functional layers (photovoltaic module), are formed of organic compounds, which can be decomposed by pyrolysis or burned by combustion, thus separating the layers into mineral materials of the sandwich.

[0005] The gases generated by the pyrolysis or combustion of polymers generally pass through a post-combustion chamber whose role is to treat these gases at high temperatures (typically greater than or equal to 850°C, in accordance with current legislation) to ensure their complete combustion, thus allowing the release of a gaseous effluent compatible with release into the atmosphere.

[0006] Because it must be kept at a high temperature and have sufficient volume to ensure a residence time of the gases to be treated greater than 2s (according to the legislation on waste incineration), a post-combustion chamber is a strong contributor to energy costs in a pyrolysis furnace. SUBJECT OF THE INVENTION

[0007] The present invention proposes a process using a pyrolysis oven, particularly suitable for the thermal dismantling of photovoltaic modules and allowing optimization of the post-combustion chamber load, in order to rationalize energy costs as much as possible. BRIEF DESCRIPTION OF THE INVENTION

[0008] The invention relates to a pyrolysis oven for recycling photovoltaic modules, configured for batch processing and comprising:

[0009] - at least one pyrolysis chamber designed to house a batch of photovoltaic modules, and isolated from the outside by a sealed door,

[0010] - a post-combustion chamber fluidically connected on one side to the pyrolysis chamber, and on the other side to a gas vent,

[0011] - primary heating methods for the pyrolysis chamber and secondary heating methods for the post-combustion chamber,

[0012] - a neutral gas distribution system, configured to inject said neutral gas into the pyrolysis chamber,

[0013] - a temperature sensor, placed in the post-combustion chamber, to measure a temperature at the core of said chamber, known as the central temperature,

[0014] - a controller configured to control the injection of neutral gas by the distribution system according to the central temperature.

[0015] According to other advantageous and non-limiting features of the invention, taken alone or in any technically feasible combination: a boundary zone between the pyrolysis chamber and the afterburner chamber is located in a portion of the pyrolysis chamber extending above the photovoltaic modules, referred to as the upper portion; the distribution system is located in a portion of the pyrolysis chamber extending below the photovoltaic modules, referred to as the lower portion; the distribution system is configured to inject the neutral gas into the pyrolysis chamber with a variable flow rate between 0 and 500 Nm³. 3 / h, between 0 and 300 Nm 3 / h, preferably between 50 Nm 3 / h and 300 Nm 3 / h, or even between 50 Nm 3 / h and 200 Nm 3 / h; the injection of neutral gas is controlled by the core temperature so that the flow rate varies to maintain the core temperature above a minimum temperature and below a maximum temperature; the minimum temperature is greater than 850°C, preferably greater than or equal to 900°C; the maximum temperature is between 1000°C and 1400°C; the pyrolysis furnace comprises a plurality of pyrolysis chambers, all fluidly connected to the post-combustion chamber.

[0016] The invention also relates to a pyrolysis process for recycling photovoltaic modules, implemented in a pyrolysis furnace as described above, the process comprising the following steps:

[0017] 1) the introduction of a batch of photovoltaic modules into the pyrolysis chamber and the closing of the airtight door, the photovoltaic modules comprising polymer layers,

[0018] 2) the heating of the post-combustion chamber to at least a regulatory temperature, and the heating of the pyrolysis chamber to a pyrolysis temperature, respectively using the second and first heating means, the second heating means being operated with an initial heating power,

[0019] 3) the generation of pyrolysis gas in the pyrolysis chamber, by thermal decomposition of the polymer layers, the pyrolysis chamber having an oxygen content of less than 5% by volume,

[0020] 4) reducing the heating power of the secondary heating means to less than 90% of the initial heating power, preferably remaining at 5% or more of the initial heating power,

[0021] 5) the injection of neutral gas into the pyrolysis chamber to push the pyrolysis gases towards the post-combustion chamber, the injection of neutral gas being carried out at a modulated flow rate so as to maintain the central temperature of the combustion chamber greater than or equal to a minimum temperature which is itself greater than the regulatory temperature,

[0022] 6) the incineration of pyrolysis gases in the post-combustion chamber.

[0023] According to other advantageous and non-limiting features of the invention, taken alone or in any technically feasible combination: in step 4), the heating power of the second heating means corresponds to less than 70%, less than 50%, or even less than 30%, or even less than 20% of the initial heating power; steps 1) to 6) apply to each of the pyrolysis chambers in a pyrolysis oven comprising a plurality of pyrolysis chambers, all fluidly connected to the post-combustion chamber; the sequence of steps 2) to 6) in each pyrolysis chamber is desynchronized from this same sequence in the other pyrolysis chambers, so that the post-combustion chamber receives the pyrolysis gases from only one pyrolysis chamber at a time. BRIEF DESCRIPTION OF THE FIGURES

[0024] 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:

[0025] This presents an exploded view of a photovoltaic panel;

[0026] This presents a pyrolysis oven according to the present invention;

[0027] This presents an example of a pyrolysis process not in accordance with the invention;

[0028] This presents an example of a pyrolysis process according to the present invention;

[0029] This presents a particular embodiment of a pyrolysis oven according to the invention.

[0030] The figures are schematic representations which, for the sake of readability, are not necessarily to scale. DETAILED DESCRIPTION OF THE INVENTION

[0031] The present invention relates to a pyrolysis oven for recycling 100 photovoltaic modules.

[0032] For the thermal dismantling of the 100 modules, with a view to recovering the mineral materials from which they are formed, a pyrolysis process is preferred to a combustion process in which the risk of degradation of the materials to be recycled is high, because the temperature during combustion is not controlled (possible melting of metals).

[0033] Figure 1 schematically presents an oven according to the invention. It is configured to perform batch processing, and not continuous processing like tunnel ovens. A batch consists of a set of photovoltaic modules 100, held in one or more supports 500, which will be introduced into the oven 1 for processing, and then removed from said oven after processing.

[0034] The oven 1 includes at least one pyrolysis chamber 2 intended to house the batch of photovoltaic modules 100. The chamber 2 is isolated from the outside by a sealed door 25. In a particular embodiment which will be described later, the oven 1 may include a plurality of pyrolysis chambers 2, independent of each other, each intended to house a batch of modules 100.

[0035] The furnace 1 also includes a post-combustion chamber 3 fluidically connected, on the one hand, to the pyrolysis chamber 2, at a proximal region 3a of the post-combustion chamber 3, and on the other hand, to a gas vent 9, at a distal region 3b of the post-combustion chamber 3. At least two temperature sensors are provided to measure the temperature: a first sensor 31 located in a central region 3c of the post-combustion chamber 3, to measure a so-called central temperature T c; and a second sensor 32 disposed in the distal region 3b, to measure a so-called outlet temperature T s The core temperature T c and the outlet temperature T s Temperatures of 850°C or higher are expected to ensure the complete combustion of pyrolysis gases, which are organic, toxic, and combustible. As mentioned in the introduction, the regulatory temperature of 850°C is defined by waste incineration legislation.

[0036] In general, a temperature sensor is also provided in the pyrolysis chamber 2.

[0037] To enable the heating of the pyrolysis chamber 2 and the post-combustion chamber 3, the oven 1 includes heating means, named first heating means 41 for heating the chamber 2 and second heating means 42,43 for heating the chamber 3.

[0038] These heating systems can take the form of burners supplied by a commercial fuel gas distribution circuit (G1) and an oxygen-containing gas distribution circuit (G2) (oxidizer). The commercial fuel gas is, for example, natural gas or liquefied petroleum gas (LPG). The oxygen-containing gas can be air.

[0039] It is important to remember that pyrolysis is an anaerobic process during which organic matter (polymers, fats, etc.) is evaporated by heat. Therefore, limiting the oxygen content in chamber 2 is critical in such a process to prevent polymer combustion. During the pyrolysis phase of the polymer layers of modules 100, the oxygen content in pyrolysis chamber 2 is preferably less than 5% by volume relative to the total gas volume in the chamber, and ideally less than 4%. The pyrolysis temperature in chamber 2 is typically between 300°C and 600°C.

[0040] As mentioned previously, pyrolysis gases generated in enclosure 2 will pass through a boundary zone between enclosure 2 and chamber 3, and enter the proximal region 3a of said chamber 3; they will then pass through the core (central region 3c) of the afterburner chamber 3. The gases resulting from the decomposition of the pyrolysis gases will finally reach the distal region 3b of chamber 3, connected to the vent 9. The vent 9 is also connected to a combustion gas treatment unit (for example, scrubber), after which the fluid can be released into the atmosphere.

[0041] A vacuum is generally created in the furnace 1 by means of a fan placed downstream of the exhaust 9. This suction mainly compensates for the overpressure generated by the combustion of the commercial fuel gas by the first heating means 41 in the pyrolysis chamber 2. Although the pyrolysis gases are substantially carried along by this flow, this fan does not constitute an active system for managing the charge of the post-combustion chamber 3 with pyrolysis gas.

[0042] To optimize this load, the furnace 1 according to the invention includes a neutral gas distribution system 6, configured to inject said neutral gas (for example, nitrogen or argon) into the pyrolysis chamber 2. By neutral gas, we mean a pure inert gas or a mixture of gases that does not react with the pyrolysis gases or other gases present in the pyrolysis chamber 2. The injection of the neutral gas aims to provide a piston effect, allowing the (highly flammable) pyrolysis gases contained in the chamber 2 to be conveyed to the afterburner chamber 3, where they will be incinerated and consequently generate thermal energy. This energy makes it possible to drastically reduce the consumption of commercial fuel gas by the secondary heating means 42, 43. Furthermore, since the pyrolysis gases release a great deal of energy when burning, the central temperature T cthe temperature of the post-combustion chamber 3 can advantageously be increased, typically between 900°C and 1400°C, or preferably between 950°C and 1200°C, and thus shorten the duration of the overall pyrolysis process.

[0043] In the embodiment illustrated in the figure, the boundary zone between the pyrolysis chamber 2 and the afterburner chamber 3 is located in the upper part 2a of the chamber 2, which extends above the batch of photovoltaic modules 100. The part of the chamber distant from the boundary zone extends below the batch of photovoltaic modules 100 and corresponds to a part referred to as the lower part 2b. In such a configuration, it is understood that the injection of neutral gas in the lower part 2b of the chamber 2 will generally push the pyrolysis gases towards the upper part 2a, in particular towards the boundary zone and the proximal region 3a of the afterburner chamber 3.

[0044] Advantageously, the distribution system 6 is configured to inject the neutral gas into the pyrolysis chamber 2 with a variable flow rate between 0 and 500 Nm 3 / h, between 0 and 300 Nm 3 / h (norm cubic meter per hour), preferably between 50 Nm 3 / h and 300 Nm 3 / h, or even between 50 Nm 3 / h and 200 Nm 3 / h. It preferably comprises a plurality of injection nozzles uniformly distributed in all or part of the lower part 2b of the pyrolysis chamber 2. It is preferable that the inert gas has a high temperature (greater than 300°C, or even greater than 400°C) when it is injected, to limit its impact on the temperature of the chamber 2. The distribution system 6 is therefore advantageously made of stainless steel and equipped with heating means.

[0045] The furnace 1 according to the invention further comprises a controller C configured to control the injection of inert gas by the distribution system 6 as a function of the central temperature T c of the afterburner chamber 3. Advantageously, the neutral gas injection is controlled by the central temperature T c so that the injection flow rate through the distribution system 6 varies to maintain the core temperature T c as stable as possible, above a minimum temperature T min and advantageously below a maximum temperature T max .

[0046] Neutral gas is injected gradually to avoid sudden pressure variations in chamber 2 or temperature variations in post-combustion chamber 3. For this, a proportional opening valve can be implemented and controlled by an electronic regulator with a set of PID (Proportional, Integral, Derivative) settings adjusted to meet the need.

[0047] The minimum temperature T min is necessarily higher than the regulatory temperature (currently 850°C). It is preferably greater than or equal to 860°C, 870°C, 900°C, 920°C, 950°C, 970°C, or even 1000°C.

[0048] The maximum temperature T max is typically between 1000°C and 1400°C, between 1000°C and 1200°C or between 1200°C and 1400°C.

[0049] The advantages of oven 1 according to the invention will be better understood with the description of the pyrolysis process, which is also the subject of the present invention.

[0050] A pyrolysis process, which aims at the recycling of 100 photovoltaic modules, typically includes four main thermal phases, as illustrated in the figure: a preliminary preheating phase of the chamber 2 up to approximately 300°C; the temperature of the post-combustion chamber 3 being at least equal to the regulatory temperature; a pyrolysis phase, between 300°C and 500°C, under an oxygen-poor or oxygen-free atmosphere (typically less than 5% by volume of oxygen), during which the polymers are decomposed and pyrolysis gases are generated in the enclosure 2 and conveyed to the post-combustion chamber 3 to be burned, at a temperature greater than or equal to 850°C (regulatory temperature); an oxidation phase, between 450°C and 600°C, under an oxidizing atmosphere (air), during which the carbon residues potentially formed during the previous phase are decomposed;a cooling phase, down to a temperature allowing the removal of mineral materials from the dismantling of the modules.

[0051] When the delivery of pyrolysis gases into the afterburner chamber 3 is not actively controlled, their relatively erratic arrival causes thermal energy spikes: the core temperature T c The afterburner of chamber 3 therefore varies in a highly random, sawtooth pattern, as seen in the diagram during part P2 (during which the polymers begin to decompose and form pyrolysis gases) of the pyrolysis phase. These erratic variations also make it difficult to minimize atmospheric emissions, particularly the generation of nitrogen oxides (NOx).

[0052] The pyrolysis process according to the invention proposes optimizing the pyrolysis gas charge of the afterburner chamber 3, so as to target a core temperature Tc greater than or equal to the minimum temperature T min and as stable as possible, and to significantly reduce the consumption of commercial fuel gas at the level of the second means of heating 42,43, during all or part of the pyrolysis phase.

[0053] The pyrolysis process, in an oven 1 as above, includes a first step 1) corresponding to the introduction of a batch of photovoltaic modules 100 into the pyrolysis chamber 2 and the closing of the sealed door 25.

[0054] The next step 2) involves raising the temperature T c from the afterburner chamber 3 to the regulatory temperature (or higher), using the second heating means 42, 43, and the temperature rise T enceinte from the pyrolysis chamber 2 to the pyrolysis temperature, using the first heating means 41.

[0055] To reach the required temperature, the second heating elements 42 and 43 are operated with an initial heating power. It should be noted that the temperature rise of the pyrolysis chamber 2 only begins after the post-combustion chamber 3 has reached the aforementioned required temperature.

[0056] Step 2) corresponds to the preliminary phase illustrated on the.

[0057] The following steps 3) to 6) of the process according to the invention take place during the pyrolysis phase ( ), simultaneously.

[0058] When the pyrolysis temperature is reached in enclosure 2, pyrolysis gases are generated by thermal decomposition of the polymer layers 131,132,133 contained in the photovoltaic modules 100 (step 3).

[0059] The heating power of the second heating means 42,43 is reduced to less than 90% of the initial heating power (step 4); advantageously, the heating power of the second heating means 42,43 remains greater than or equal to 5% of the initial heating power, or even greater than or equal to 10% of the initial heating power.

[0060] Preferably, the heating output of the secondary heating means 42, 43 is reduced to less than 80%, 70%, 60%, 50%, 40%, 30%, or even 20% of the initial heating output. This reduction in the heating output of the secondary heating means 42, 43 corresponds to a reduction in the commercial fuel gas supply rate. The commercial gas consumption is reduced in the same proportion as the heating output, which is particularly advantageous in terms of energy costs.

[0061] Neutral gas is injected into chamber 2 using distribution system 6, so as to push the pyrolysis gases towards the post-combustion chamber 3 (stage 5). This injection is controlled by controller C. The neutral gas flow rate is modulated to maintain the core temperature T c of the post-combustion chamber 3 above the minimum temperature T min defined. The injection of neutral gas, controlled by the central temperature T c This allows control of the pyrolysis gas charge in the afterburner chamber 3. This charge replaces the commercial fuel gas, the consumption of which can be significantly reduced during at least part P2 of the pyrolysis phase. Of course, the supply of oxidizer (e.g., air) to the secondary heating means 42, 43 remains necessary to enable combustion.

[0062] The pyrolysis gases are incinerated in the afterburner chamber 3 (stage 6). The significant energy they release makes it possible to maintain the core temperature T c of chamber 3 above 850°C, greater than or equal to 900°C, 950°C, or even 1000°C. Since the pyrolysis gases are continuously and in a controlled manner conveyed from the pyrolysis chamber 2 to the post-combustion chamber 3, and their combustion is carried out at a higher temperature, the pyrolysis phase can advantageously be shortened. The reduction in pyrolysis time is another advantage of the present invention, which also results in energy savings.

[0063] Remember that after the pyrolysis phase, the other phases (oxidation, cooling) can be implemented in a conventional way.

[0064] According to a particular embodiment of the invention, the pyrolysis furnace 1 comprises a plurality of pyrolysis chambers 2i, 2ii, 2iii, 2iv. Steps 1) to 6) of the described pyrolysis process apply to each of the chambers 2i, 2ii, 2iii, 2iv. However, the pyrolysis phase in each chamber is desynchronized from that in the other chambers. In other words, the afterburner 3 is supplied with pyrolysis gas from only one chamber at a time (chamber 2iii in the first instance). The chamber(s) that are in the loading or unloading phase (for example, chamber 2i) is / are isolated from the afterburner 3 by a hatch 7i, 7ii, 7iii, 7iv, and connected to a chimney. From the preliminary heating phase to the cooling phase, enclosures 2ii, 2iii, 2iv have their hatch 7ii, 7iii, 7iv open to allow direct communication with chamber 3.However, there is only one pyrolysis phase which takes place in enclosure 2iii, enclosures 2ii and 2iv being respectively in preliminary phase and cooling phase.

[0065] This multi-chamber configuration of the pyrolysis furnace 1 further optimizes the energy costs associated with the post-combustion chamber 3, which represent more than 65% of the total heating costs of a conventional pyrolysis furnace. Indeed, the energy cost of heating the post-combustion chamber 3 is amortized over several pyrolysis cycles, and the multiple pyrolysis phases (one pyrolysis phase in each chamber 2i, 2ii, 2iii, 2iv) are achieved by optimizing the pyrolysis gas charge according to the process of the invention.

[0066] The present invention optimizes the pyrolysis gas charge delivered to the afterburner chamber 3, thereby significantly reducing the consumption of commercial fuel gas required to maintain said chamber 3 at a high temperature. Furthermore, the fact that the central temperature T c Maintaining a relatively stable and elevated temperature (above a defined minimum temperature) in the afterburner chamber 3 throughout the pyrolysis phase reduces the duration of the pyrolysis phase and improves the quality of atmospheric gas emissions after venting and treatment. All of this results in significant energy savings compared to a conventional pyrolysis process.

[0067] 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

A pyrolysis process for recycling photovoltaic modules (100), implemented in a pyrolysis furnace (1) configured for batch processing and comprising: - at least one pyrolysis chamber (2) intended to hold a batch of photovoltaic modules (100), and isolated from the outside by a sealed door (25), - a post-combustion chamber (3) fluidically connected, on one side, to the pyrolysis chamber (2), and on the other, to a gas vent (9), - first heating means (41) for the pyrolysis chamber (2) and second heating means (42, 43) for the post-combustion chamber (3), - a neutral gas distribution system (6), configured to inject said neutral gas into the pyrolysis chamber (2), - a temperature sensor (31), disposed in the post-combustion chamber (3), for measuring a temperature at the core of said chamber, called the core temperature (T c),- a controller (C) configured to control the injection of neutral gas by the distribution system (6) as a function of the central temperature (T cThe pyrolysis process comprises the following steps: 1) introducing a batch of photovoltaic modules (100) into the pyrolysis chamber (2) and closing the airtight door (25), the photovoltaic modules (100) comprising polymer layers (131, 132, 133); 2) heating the afterburner chamber (3) to at least a regulatory temperature, and heating the pyrolysis chamber (2) to a pyrolysis temperature, respectively, using the second (42, 43) and first (41) heating means, the second heating means (42, 43) being operated with an initial heating power; 3) generating pyrolysis gas in the pyrolysis chamber (2) by thermal decomposition of the polymer layers (131, 132, 133), the pyrolysis chamber (2) having an oxygen content of less than 5%. volume,4) the reduction of the heating power of the second means of heating (42,43),at less than 90% of the initial heating power, preferably remaining at 5% or more of the initial heating power, 5) the injection of neutral gas into the pyrolysis chamber (2) to push the pyrolysis gases towards the post-combustion chamber (3), the injection of neutral gas being carried out at a modulated flow rate so as to maintain the core temperature (T, c ) of the combustion chamber (3) greater than or equal to a minimum temperature (T min ) itself higher than the regulatory temperature, 6) the incineration of pyrolysis gases in the post-combustion chamber (3). Pyrolysis process according to the preceding claim, wherein in step 4), the heating power of the second heating means (42,43) corresponds to less than 70%, less than 50%, or even less than 30%, or even less than 20% of the initial heating power. A pyrolysis process according to any one of the preceding claims, wherein: - a boundary zone between the pyrolysis chamber (2) and the post-combustion chamber (3) is located in a part of the pyrolysis chamber (2) which extends above the photovoltaic modules (100), referred to as the upper part (2a), and - the distribution system (6) is arranged in a part of the pyrolysis chamber (2) which extends below the photovoltaic modules (100), referred to as the lower part (2b). A pyrolysis process according to any one of the preceding claims, wherein the distribution system (6) is configured to inject the neutral gas into the pyrolysis chamber (2) with a variable flow rate between 0 and 500 Nm 3 / h, preferably between 50 Nm 3 / h and 300 Nm 3 / h. A pyrolysis process according to any one of the preceding claims, wherein the neutral gas has a temperature above 300°C, or even above 400°C, at the time of its injection. A pyrolysis process according to any one of the preceding claims, wherein the minimum temperature (T min ) is greater than 850°C, preferably greater than or equal to 900°C. A pyrolysis process according to any one of the preceding claims, wherein the maximum temperature (T max ) is between 1000°C and 1400°C. A pyrolysis process according to any one of the preceding claims, wherein: - the pyrolysis furnace comprises a plurality of pyrolysis chambers (2i, 2ii, 2iii, 2iv), all fluidly connected to the post-combustion chamber (3), - steps 1) to 6) are applied to each of the pyrolysis chambers (2i, 2ii, 2iii, 2iv), and - the sequence of steps 2) to 6) in each pyrolysis chamber is desynchronized from this same sequence in the other pyrolysis chambers, so that the post-combustion chamber (3) receives pyrolysis gases from only one pyrolysis chamber (2iii) at a time.

Images