MÉTODO PARA A PIRÓLISE DE UM PLÁSTICO

Abstract

The invention relates to a method for pyrolyzing a plastic, in particular a recycled plastic, having the steps of (a) pyrolyzing the plastic in a first pyrolysis reactor in order to obtain a first pyrolysis product, (b) separating a pyrolysis residue from the first pyrolysis product in a first separating unit, (c) separating the pyrolysis residue into a solids-depleted fraction and a solids-enriched fraction in a second separating unit, and (d) pyrolyzing the solids-enriched fraction in a second pyrolysis reactor in order to obtain a second pyrolysis product. The invention additionally relates to a device for pyrolyzing a plastic using said method.

Description

[0001] The present invention relates to a method and a device for the pyrolysis of a plastic, in particular a plastic waste.

[0002] Methods for the pyrolysis of a starting material, in particular a plastic, are known in the prior art. The focus here is on separating a gaseous fraction from a pyrolysis product, while the remainder of the pyrolysis product, in particular a fraction with a high solids content, is typically used for energy purposes.

[0003] For example, EP 1 154 007 A1 describes a method for the pyrolysis of a plastic waste. In this case, the plastic waste is subjected to pyrolysis in a first pyrolysis reactor at a first temperature, obtaining a first pyrolysis product comprising a first gaseous fraction and a first pyrolysis residue. The first pyrolysis residue is then subjected to pyrolysis in a second pyrolysis reactor at a second temperature higher than the first, obtaining a second pyrolysis product comprising a second gaseous fraction and a second pyrolysis residue. The second pyrolysis residue is subjected to a magnetic separation method to obtain inorganic fillers and metal scrap.

[0004] An additional method for the pyrolysis of a plastic waste is described in WO 2016 / 116114 A1. The plastic waste is converted in a pyrolysis reactor into a pyrolysis product comprising a gaseous fraction and a solid pyrolysis residue. The pyrolysis residue is then separated in a separation unit, for example, in a cyclone, into a low-solids fraction and a high-solids fraction. The low-solids fraction is returned to the pyrolysis reactor for further pyrolysis. The high-solids fraction is separated in a sedimentation tank based on its density. A first portion of the high-solids, lower-density fraction is returned to the pyrolysis reactor along with the low-solids fraction. Petition 870250083713, dated 09 / 17 / 2025, page 7 / 43 2 / 25 of the solids content, while a second portion of the fraction with a high solids content and higher density can be used as a high-energy fuel.

[0005] Other methods for the pyrolysis of starting materials are known in WO 2017 / 168163 A1, US 2022 / 340819 A1, US 2012 / 117860 A1 and EP 4 151 702 A1.

[0006] It is true that the product of pyrolysis can be at least partially recycled using some of these methods. However, there is a need for a method with a reduced CO2 footprint and a greater contribution to the circular economy and sustainability. One of the objectives of this invention is to recycle a larger portion of the pyrolysis residue compared to known methods.

[0007] The method according to the invention for the pyrolysis of a plastic comprises the following steps: (a) pyrolysis of the plastic in a first pyrolysis reactor to obtain a first pyrolysis product, (b) separation of a pyrolysis residue from the first pyrolysis product in a first separation unit, (c) separation of the pyrolysis residue into a low-solids fraction and a high-solids fraction in a second separation unit, and (d) pyrolysis of the high-solids fraction in a second pyrolysis reactor to obtain a second pyrolysis product.

[0008] The invention is further directed to a device for the pyrolysis of a plastic, in particular of a plastic waste, the method according to the invention comprising a first pyrolysis reactor for the pyrolysis of the plastic, a first separation unit for separating the pyrolysis residue from the first pyrolysis product, a second separation unit for separating the pyrolysis residue Petition 870250083713, dated 09 / 17 / 2025, page 8 / 43 3 / 25 in the low-solids fraction and in the high-solids fraction, and a second pyrolysis reactor for the pyrolysis of the high-solids fraction.

[0009] By performing two pyrolysis steps in two different pyrolysis reactors and separating the pyrolysis residue into a low-solids fraction and a high-solids fraction between the two pyrolysis steps, this method and device allow the first or second pyrolysis product to be processed particularly well and separated into individual components, enabling a high degree of recyclability. The method can therefore alleviate environmental impact, as greenhouse gas emissions and the amount of waste can be reduced. Overall, this can significantly reduce resource consumption and strengthen the circular economy, which can also bring economic benefits.

[0010] The plastic preferably comprises a polyolefin and / or polystyrene (PS), wherein the polyolefin may comprise polyethylene (PE) and / or polypropylene (PP). The plastic preferably comprises polyolefin and / or polystyrene in an amount of at least 65% by weight, more preferably at least 70% by weight, in particular at least 90% by weight, based on the total weight of the plastic. As a result, a pyrolysis residue comprising a significant proportion of an aliphatic hydrocarbon (or a mixture of a plurality of aliphatic hydrocarbons) may be obtained.

[0011] The plastic preferably comprises at least 20% by weight of polyolefin, more preferably at least 50% by weight, even more preferably at least 70% by weight, in particular at least 90% by weight, based on the total weight of the plastic. As the proportion of polyolefin increases, the amount of wax obtained by the method according to the invention can be increased, which Petition 870250083713, dated 09 / 17 / 2025, p. 9 / 43 4 / 25 can improve the cost-effectiveness of the method. The plastic may comprise an additional polymer from the group consisting of thermoplastics, thermosetting resins and / or elastomers, in particular an acrylonitrile-butadiene-styrene copolymer (ABS), a polyvinyl chloride (PVC), a polyamide (PA) and / or a polyester.

[0012] Before step (a) of the method, the plastic can be plasticized, for example, in a mixer, in particular in an extruder. The plastic is preferably heated to a temperature of at least 120°C to plasticize it, more preferably to a temperature of 200 to 500°C, and even more preferably from 400 to 470°C. Subsequent pyrolysis can then be carried out with greater energy efficiency and in less time.

[0013] In the extruder, the plastic can also be degassed to produce a uniform mass without gaseous inclusions, so that a homogeneous pyrolysis product can be obtained by subsequent pyrolysis.

[0014] Before step (a) of the method, a diluent to reduce viscosity may be added to the plastic, in particular to plasticized plastic. For this purpose, the device may have an introduction device configured to add a diluent to reduce viscosity to the plastic before pyrolysis in the first pyrolysis reactor. The diluent is preferably added to the plastic in an amount of at least 5% by weight, more preferably at least 9% by weight, based on the total weight of the plastic. The plastic to diluent ratio is preferably at least 1:4, preferably at least 1:9. By adding the diluent to the plastic, the mobility of the polymer chains can be increased at a given temperature, so that the heat input to the plastic can be improved during pyrolysis. In addition, due to the reduction in viscosity, the risk of overheating of the plastic in the areas of the walls of the pyrolysis reactor is reduced. Petition 870250083713, dated 09 / 17 / 2025, p. 10 / 43 5 / 25 can be reduced, since it is normally heated by a heating device installed near an outer wall of the pyrolysis reactor. The risk of coking of the plastic during pyrolysis can also be reduced by reducing the viscosity.

[0015] By adding the thinner to the plastic, its viscosity can preferably be reduced by at least 30%, more preferably by at least 50%, and particularly preferably by at least 80%, based on the viscosity of the plastic without thinner under the same measurement conditions, in particular at a temperature in the range of 180 to 240°C. This can improve the pumpability of the plastic, which can facilitate its processing.

[0016] When the diluent is added, the plastic preferably has a temperature of at least 120°C, more preferably a temperature of 150 to 300°C, in particular 200 to 300°C. Alternatively or additionally, the diluent can be heated to a temperature preferably of at least 120°C, more preferably of at least 150°C, in particular 200 to 300°C, before being added to the plastic. By increasing the temperature of the plastic and / or diluent, the diluent can be mixed with the plastic more quickly and efficiently. Subsequent pyrolysis can also be carried out more quickly and with greater energy efficiency.

[0017] The diluent can be added to the plastic by means of a feeding device. The feeding device may have a dosing device, such as a dosing pump. For example, the plastic, in particular plasticized plastic, can be fed into a mixer, for example, a static mixer, and mixed with the diluent. If the plastic is plasticized in an extruder, the diluent can be added directly to the extruder. For this purpose, the feeding device can be installed, for example, in the compression zone or in the mixing zone of the extruder. Petition 870250083713, dated 09 / 17 / 2025, page 11 / 43 6 / 25

[0018] The diluent may comprise a hydrocarbon selected from an alkane, a cycloalkane and / or an aromatic. As a result of pyrolysis, this diluent may be converted into a gaseous and / or liquid product, which may be at least partially separated from the pyrolysis residue and reused. In particular, the diluent may comprise a fraction obtained from crude oil, preferably a heavy oil. The heavy oil may be an oil obtained from petroleum in an oil refinery, for example, a residual oil from a pyrolysis system. The heavy oil preferably has a proportion of an aromatic hydrocarbon of at least 25% by weight, based on the total weight of the heavy oil.

[0019] Alternatively or additionally, the diluent may comprise a portion of the liquid fraction of the first pyrolysis product and / or a portion of the low-solids fraction. This may allow for the reuse of the liquid fraction and the low-solids fraction. The diluent preferably consists of at least a portion of the liquid fraction of the first pyrolysis product and / or at least a portion of the low-solids fraction. Thus, a high degree of recyclability can be achieved.

[0020] The diluent preferably has a boiling point (or a lower end of a boiling range) of at least 300°C, in particular at least 350°C. As a result, the diluent can be prevented from evaporating immediately after the introduction of a plastic and diluent mixture into the pyrolysis reactor, but evaporation, cleavage and / or depolymerization of the diluent can only occur with the progressive residence time of the mixture in the pyrolysis reactor and the associated heating of the mixture. As a result, a homogeneous pyrolysis product can be obtained.

[0021] Na etapa (a) do método, o plástico é pirolizado em um primeiro reator de pirólise. O primeiro reator de pirólise pode ser um reator Petição 870250083713, de 17 / 09 / 2025, pág. 12 / 43 7 / 25 de rosca transportadora, um reator de leito fluidizado, um reator de tubo rotativo ou um coqueificador, de preferência um coqueificador.

[0022] In step (a) of the method, the temperature in the first pyrolysis reactor is preferably in the range of 300 to 800°C, more preferably 350 to 700°C. The pressure in the first pyrolysis reactor in step (a) is preferably in the range of 1 to 30 bar, more preferably 5 to 30 bar, even more preferably 10 to 25 bar. Furthermore, pyrolysis is preferably carried out in step (a) for a period of 0.3 min, more preferably for a period of 1 to 10 min, in particular 1.5 to 5 min. As a result, a good balance between cost-effectiveness and efficiency of the method can be achieved.

[0023] Pyrolysis in step (a) can be thermal pyrolysis (i.e., thermal cracking, without the addition of a catalyst) and / or catalytic pyrolysis (i.e., catalytic cracking). Thermal pyrolysis is preferred to avoid any contamination of the wax and / or the solid due to the catalyst components.

[0024] Pyrolysis in step (a) can be carried out to a large extent in the absence of oxygen, in particular in an inert atmosphere, for example, under nitrogen. Due to the lack or exclusion of oxygen, complete combustion can be avoided and a polymer contained in the plastic can be cleaved or depolymerized.

[0025] The first pyrolysis product comprises a pyrolysis residue. In addition, the first pyrolysis product comprises a liquid fraction and / or a gaseous fraction. In step (b) of the method, the pyrolysis residue is separated from the first pyrolysis product in a first separation unit. The separation may occur by evaporation and / or centrifugal separation (i.e., centrifugation), preferably by centrifugal separation. Consequently, the first separation unit may comprise an evaporator, a cyclone and / or a hydrocyclone, in particular a hydrocyclone. Petition 870250083713, dated 09 / 17 / 2025, page 13 / 43 8 / 25

[0026] The temperature in the first separation unit in step (b) is preferably in the range of 300 to 700°C, more preferably in the range of 330 to 420°C. The pressure in the first separation unit in step (b) is preferably in the range of 1 to 15 bar, more preferably in the range of 2 to 8 bar. Efficient and good quality separation of the pyrolysis residue can be achieved with these method parameters.

[0027] The first separation unit preferably has a hydrocyclone, with which the gaseous fraction, the liquid fraction and the pyrolysis residue can be separated in just one process step. Such a hydrocyclone is described in application WO 2023 / 036751 A1. By introducing the first pyrolysis product through an inlet located in the upper region of a hydrocyclone casing, a vortical flow can be generated in the hydrocyclone, which allows the gaseous fraction to be separated from the first pyrolysis product and discharged through an outlet located in the upper region of the hydrocyclone (e.g., on its roof). The remaining portion of the first pyrolysis product can then be discharged towards the lower portion of the hydrocyclone due to gravity, where the tangential velocity of the vortical flow formed can continuously increase.As a result, at least a portion of the pyrolysis residue can be discharged through an outlet located in the lower portion of the hydrocyclone, while at least a portion of a liquid fraction of the first pyrolysis product can pass into an internal container located in the hydrocyclone and be discharged from there through an outlet. This portion of the liquid fraction can then be used as a diluent for reducing the viscosity of the plastic before step (a) of the method. The pyrolysis residue discharged through the outlet located in the lower portion of the hydrocyclone can then be used in step (c) of the method. The hydrocyclone is preferably operated at a temperature within the range. Petition 870250083713, dated 09 / 17 / 2025, p. 14 / 43 9 / 25 from 300 to 450°C, more preferably from 320 to 420°C, particularly preferably from 360 to 400°C.

[0028] The pyrolysis residue separated in step (b) of the method preferably has a boiling point (or a lower end of a boiling range) of at least 250°C, more preferably at least 300°C, even more preferably at least 330°C, particularly preferably at least 350°C. The boiling point (or boiling range) of the pyrolysis residue can be determined using ASTM D7500-15:2019 standard (preferably if the pyrolysis residue has a boiling point or boiling range of 100 to 850°C, in particular 100 to 735°C) or using ASTM D2887-22:2022 standard (preferably if the pyrolysis residue has a boiling point or boiling range of 55 to 538°C).

[0029] The pyrolysis residue separated in step (b) of the method preferably comprises a carbon fraction having at least 14 carbon atoms per molecule, more preferably at least 16 carbon atoms per molecule, particularly preferably at least 18 carbon atoms per molecule. The pyrolysis residue can then be further separated in the following step (c) of the method.

[0030] In step (c) of the method, the pyrolysis residue is separated in a second separation unit into a low-solids fraction and a high-solids fraction. The low-solids fraction preferably has a liquid proportion of more than 70% by weight, preferably more than 80% by weight, more preferably more than 85% by weight, more preferably more than 90% by weight, more preferably more than 95% by weight, more preferably more than 98% by weight, more preferably more than 99% by weight. The low-solids fraction preferably has a liquid proportion in the range of 80 to 100% by weight, more preferably 90 Petition 870250083713, dated 09 / 17 / 2025, page 15 / 43 10 / 25 to 99.9% by weight, based on the total weight of the low-solids fraction. The low-solids fraction preferably has a density at 20°C and 101325 Pa in the range of 0.600 to 1.100 g / cm3, more preferably from 0.750 to 0.990 g / cm3.

[0031] The high-solids fraction preferably has a liquid content of less than 95% by weight, preferably less than 90% by weight, more preferably less than 85% by weight, more preferably less than 80% by weight, more preferably less than 75% by weight, more preferably less than 70% by weight. The high-solids fraction preferably has a liquid content in the range of 50 to 95% by weight, more preferably 70 to 90% by weight, based on the total weight of the high-solids fraction. The high-solids fraction preferably has a density at 20°C and 101325 Pa in the range of 0.650 to 1.300 g / cm³, more preferably 0.800 to 1.150 g / cm³. Preferably, the high-solids fraction has a lower proportion of liquids than the low-solids fraction. It is also preferable that the high-solids fraction has a higher density at 20°C and 101325 Pa than the low-solids fraction.

[0032] The separation in the second separation unit may comprise gravimetric separation, filtration and / or centrifugal separation, preferably centrifugal separation. Gravimetric separation may include sedimentation and / or decantation. Consequently, the second separation unit may comprise a gravimetric separation device, a filter, a centrifuge and / or a hydrocyclone, preferably a hydrocyclone. The gravimetric separation device may comprise a sedimentation system and / or a decanter. If the second separation unit comprises a hydrocyclone, it may be constructed and operated in the same or similar manner to the hydrocyclone of the first separation unit, as per Petition 870250083713, dated 09 / 17 / 2025, page 16 / 43 11 / 25 described above.

[0033] Preferably, the separation in the second separation unit in step (c) comprises centrifugal separation in combination with filtration or gravimetric separation. Centrifugal separation may occur before filtration or before gravimetric separation. Consequently, the second separation unit may include the hydrocyclone in combination with the filter or gravimetric separation device. The hydrocyclone may be upstream of the filter or gravimetric separation device. In this way, precise separation between the low-solids fraction and the high-solids fraction can occur.

[0034] The temperature in the second separation unit in step (c) is preferably in the range of 100 to 700°C, more preferably 100 to 350°C, even more preferably 100 to 200°C. During gravimetric separation or filtration, the temperature is preferably in the range of 180 to 700°C. During centrifugation, the temperature is preferably 200°C or less, more preferably in the range of 100 to 180°C. During centrifugal separation, the temperature is preferably in the range of 200 to 700°C. If the temperature is selected as indicated, depending on the method, separation into a low-solids fraction and a high-solids fraction can occur efficiently.

[0035] In step (d) of the method, the high-solids fraction is subjected to pyrolysis in a second pyrolysis reactor to obtain a second pyrolysis product. The second pyrolysis reactor can be a screw conveyor reactor, a fluidized bed reactor, a rotary tube reactor, or a coke oven, preferably a coke oven. The temperature in the second pyrolysis reactor is preferably in the range of 400 to 800°C, more preferably in the range of 500 to 700°C. This allows the high-solids fraction to be subjected to Petition 870250083713, dated 09 / 17 / 2025, page 17 / 43 12 / 25 pyrolysis efficiently.

[0036] The temperature during pyrolysis in the second pyrolysis reactor in step (d) may be higher than the temperature during pyrolysis in the first pyrolysis reactor in step (a). The temperature in the second pyrolysis reactor is preferably at least 50°C higher than the temperature in the first pyrolysis reactor, more preferably at least 80°C, even more preferably at least 100°C, even more preferably at least 150°C, in particular at least 200°C.

[0037] The pressure in the second pyrolysis reactor is preferably in the range of 1 to 20 bar, more preferably in the range of 2 to 12 bar, in particular from 2 to 8 bar. In the second pyrolysis reactor, pyrolysis is preferably carried out for a period of 1 to 90 minutes, in particular from 1.5 to 5 minutes. As a result, a good balance between cost-effectiveness and efficiency of the method can be achieved.

[0038] The ratio of the volumetric capacity of the first pyrolysis reactor to the second pyrolysis reactor is at most 10:3, more preferably at most 10:2, preferably in the range of 10:0.2 to 10:2, in particular from 10:1 to 10:2. Volumetric capacity means the maximum possible load level of the respective pyrolysis reactor.

[0039] The second pyrolysis product may comprise a solid, a gas and / or a liquid.

[0040] The quantity of gas is preferably at least 10% by weight, more preferably at least 20% by weight, even more preferably at least 40% by weight, based on the total weight of the second pyrolysis product. The gas preferably comprises a carbon fraction of at least 5% by weight, more preferably at least 15% by weight, even more preferably at least 20% by weight, in particular at least 40% by weight, based on the total weight of the gas. The carbon fraction of the gas preferably comprises methane, ethane, ethene, propane, propene, Petition 870250083713, dated 09 / 17 / 2025, page 18 / 43 13 / 25 butane, butene, butadiene, or a mixture of these components. These gas components can be separated from each other, for example, through fractional distillation, in order to supply them for later use, for example, in other systems of a refinery.

[0041] The liquid preferably comprises an oil, wherein the oil may comprise a light oil and a heavy oil. The light oil may comprise a carbon fraction of 3 to 14 carbon atoms per molecule and the heavy oil may comprise a carbon fraction of 11 to 50 carbon atoms per molecule. The separation of the individual components of the oil, in particular the individual components of the carbon fraction, may occur, for example, by fractional distillation, which allows subsequent use, for example, as a fuel. The separation of the gas and liquid from each other and the separation of the gas and / or liquid into individual components may be carried out in the same distillation apparatus.

[0042] The amount of solid is preferably a maximum of 70% by weight, more preferably a maximum of 55% by weight, even more preferably a maximum of 30% by weight, based on the total weight of the second pyrolysis product. The solid may comprise an inorganic salt, a ceramic raw material, an asphaltene, a tar and / or a coke. In particular, the solid may comprise talc, an iron oxide (e.g., ferric oxide), aluminum oxide, titanium dioxide, magnesium oxide and / or calcium carbonate. If the pyrolysis residue supplied is obtained by the pyrolysis of a plastic, the solid may contain an additive contained in the plastic. For example, the additive may comprise a filler, a color pigment and / or an additive. An expert knows which additives are used depending on the respective plastic and the area of ​​application.

[0043] The method may comprise an additional step (e): separating at least a portion of the solid from the second pyrolysis product. Petition 870250083713, dated 09 / 17 / 2025, page 19 / 43 14 / 25 For this purpose, the device may have a solid separation device.

[0044] The separation of the solid from the second pyrolysis product may comprise gravimetric separation, filtration and / or centrifugal separation, preferably filtration. Gravimetric separation may include sedimentation and / or decantation. If the separation comprises filtration, this may be carried out with a filter medium, which may comprise activated carbon or bleaching earth. As a result, any polar components (e.g., tar or polyphenol) dissolved in the solvent along with the wax may be separated and adsorbed by the filter medium. During filtration, particles with an average size (D50) less than 100 µm, in particular less than 50 µm, may also be easily removed (determined by laser diffractometry).

[0045] The separation of the solid from the second pyrolysis product can also occur directly in the second pyrolysis reactor. For these purposes, the second pyrolysis reactor is preferably a screw conveyor reactor. The solid can be discharged directly from the extruder via a discharge device.

[0046] After separation of the second pyrolysis product, i.e., after step (e) of the method, the solid can be dried, for example, in an oven. As a result, the solid can flow freely and therefore be easier to process. The solid is preferably dried at a temperature in the range of 50 to 250°C, more preferably 100 to 200°C, and even more preferably 130 to 160°C. The drying time is preferably up to 120 min, in particular 5 to 60 min. One or more components can be separated from the solid, in particular from the dried solid, and then reused, for example, as an additive for a plastic.

[0047] The invention relates, in particular, to the following embodiments: Petition 870250083713, dated 09 / 17 / 2025, p. 20 / 43 15 / 25 1. A method for the pyrolysis of a plastic, in particular a plastic waste, comprising the following steps: (a) pyrolysis of the plastic in a first pyrolysis reactor to obtain a first pyrolysis product, (b) separation of a pyrolysis residue from the first pyrolysis product in a first separation unit, (c) separation of the pyrolysis residue into a low-solids fraction and a high-solids fraction in a second separation unit, and (d) pyrolysis of the high-solids fraction in a second pyrolysis reactor to obtain a second pyrolysis product. 2. The method according to embodiment 1, wherein the plastic comprises a polyolefin and / or polystyrene (PS), wherein the polyolefin preferably comprises polyethylene (PE) and / or polypropylene (PP). 3. The method according to embodiment 2, wherein the plastic comprises polyolefin and / or polystyrene in an amount of at least 65% by weight, more preferably at least 70% by weight, in particular at least 90% by weight, based on the total weight of the plastic. 4. The method according to embodiment 2 or 3, wherein the plastic comprises at least 20% by weight of a polyolefin, preferably at least 50% by weight, more preferably at least 70% by weight, in particular at least 90% by weight, based on the total weight of the plastic. 5. The method according to any of the preceding embodiments, in which the plastic is heated to a temperature of at least 120°C, preferably to a temperature of 200 to 500°C, more preferably 400 to 470°C, before step (a). 6. The method according to any of the preceding embodiments, in which a viscosity-reducing diluent is added to the plastic. Petition 870250083713, dated 09 / 17 / 2025, p. 21 / 43 16 / 25 before stage (a). 7. The method according to embodiment 6, in which the diluent is added to the plastic in an amount of at least 5% by weight, more preferably at least 9% by weight, based on the total weight of the plastic. 8. The method according to embodiment 6 or 7, in which the ratio of plastic to diluent is at least 1:4, preferably at least 1:9. 9. The method according to any of the embodiments from 6 to 8, wherein the diluent comprises a hydrocarbon selected from an alkane, a cycloalkane and / or an aromatic. 10. The method according to any of the embodiments from 6 to 9, wherein the diluent comprises a fraction obtained from crude oil, preferably a heavy oil, in particular a heavy oil having an aromatic hydrocarbon content of at least 25% by weight, based on the total weight of the heavy oil. 11. The method according to any of the embodiments from 6 to 10, wherein the diluent comprises a portion of the liquid fraction of the first pyrolysis product and / or a portion of the low-solids fraction. 12. The method according to any of the embodiments from 6 to 11, in which the diluent has a boiling point of at least 300°C, preferably at least 350°C. 13. The method according to any of the embodiments from 6 to 12, in which the diluent and / or the plastic is / are heated to a temperature of at least 120°C, preferably at least 150°C, before the addition of the diluent to the plastic, preferably at a temperature in the range of 150 to 300°C, more preferably 200 to 300°C. 14. The method according to any of the preceding embodiments, wherein the temperature in the first pyrolysis reactor in step (a) is in the range of 300 to 800°C, preferably 350 to 700°C. Petition 870250083713, dated 09 / 17 / 2025, p. 22 / 43 17 / 25 15. The method according to any of the preceding embodiments, wherein the pressure in the first pyrolysis reactor in step (a) is in the range of 1 to 30 bar, preferably 5 to 30 bar, more preferably 10 to 25 bar. 16. The method according to any of the preceding embodiments, in which pyrolysis is carried out in step (a) for a period of at least 0.3 min, preferably for a period of 1 to 10 min, in particular 1.5 to 5 min. 17. The method according to any of the preceding embodiments, wherein the separation in the first separation unit in step (b) comprises evaporation and / or centrifugal separation, preferably centrifugal separation. 18. The method according to any of the preceding embodiments, wherein the temperature in the first separation unit in step (b) is in the range of 300 to 700°C, preferably 330 to 420°C. 19. The method according to any of the preceding embodiments, wherein the pressure in the first separation unit in step (b) is in the range of 1 to 15 bar, preferably 2 to 8 bar. 20. The method according to any of the preceding embodiments, wherein the pyrolysis residue separated in step (b) has a boiling point of at least 250°C, preferably at least 300°C, more preferably at least 330°C, most preferably at least 350°C. 21. The method according to any of the preceding embodiments, wherein the pyrolysis residue separated in step (b) comprises a carbon fraction having at least 14 carbon atoms per molecule, preferably at least 16 carbon atoms per molecule, more preferably at least 18 carbon atoms per molecule. 22. The method according to any of the modalities Petition 870250083713, dated 09 / 17 / 2025, p. 23 / 43 18 / 25 preceding, wherein the low-solids fraction has a liquid proportion of more than 70% by weight, preferably more than 80% by weight, more preferably more than 85% by weight, more preferably more than 90% by weight, more preferably more than 95% by weight, more preferably more than 98% by weight, more preferably more than 99% by weight. 23. The method according to any of the preceding embodiments, wherein the fraction with a high solids content has a liquid proportion of less than 95% by weight, preferably less than 90% by weight, more preferably less than 85% by weight, more preferably less than 80% by weight, more preferably less than 75% by weight, more preferably less than 70% by weight. 24. The method according to any of the preceding embodiments, wherein the low-solids fraction has a liquid proportion in the range of 80 to 100% by weight, preferably 90 to 99.9% by weight, based on the total weight of the low-solids fraction; and / or wherein the high-solids fraction has a liquid proportion in the range of 50 to 95% by weight, preferably 70 to 90% by weight, based on the total weight of the high-solids fraction. 25. The method according to any of the preceding embodiments, wherein the low-solids fraction has a density at 20°C and 101325 Pa in the range of 0.600 to 1.100 g / cm3, preferably 0.750 to 0.990 g / cm3, based on the total weight of the low-solids fraction; and / or wherein the high-solids fraction has a density at 20°C and 101325 Pa in the range of 0.650 to 1.300 g / cm3, preferably 0.800 to 1.150 g / cm3, based on the total weight of the high-solids fraction. 26. The method according to any of the preceding modalities, in which the temperature in the second separation unit in the step Petition 870250083713, dated 09 / 17 / 2025, page 24 / 43 19 / 25 (c) is in the range of 100 to 700oC, preferably 100 to 350oC, more preferably 100 to 200oC. 27. The method according to any of the preceding embodiments, wherein the separation in the second separation unit in step (c) comprises gravimetric separation, filtration and / or centrifugal separation, preferably centrifugal separation. 28. The method according to embodiment 27, wherein the separation in the second separation unit in step (c) comprises centrifugal separation in combination with filtration or gravimetric separation. 29. The method according to embodiment 27, in which centrifugal separation occurs before filtration or before gravimetric separation. 30. The method according to any of the embodiments in 27 to 29, wherein the temperature during gravimetric separation or filtration is in the range of 180 to 700°C; wherein the temperature during centrifugation is 200°C or less, more preferably in the range of 100 to 180°C; and / or wherein the temperature during centrifugal separation is in the range of 200 to 700°C. 31. The method according to any of the preceding embodiments, wherein the temperature in the second pyrolysis reactor in step (d) is in the range of 400 to 800°C, preferably in the range of 500 to 700°C. 32. The method according to any of the preceding embodiments, wherein the temperature during pyrolysis in the second pyrolysis reactor in step (d) is higher than the temperature during pyrolysis in the first pyrolysis reactor in step (a). 33. The method according to embodiment 32, wherein the temperature in the second pyrolysis reactor is at least 50°C higher than the temperature in the first pyrolysis reactor, preferably at least 80°C, more preferably at least 100°C, even more preferably at least 150°C, in particular at least 200°C. 34. The method according to any of the modalities Petition 870250083713, dated 09 / 17 / 2025, p. 25 / 43 20 / 25 preceding, wherein the pressure in the second pyrolysis reactor in step (d) is in the range of 1 to 20 bar, preferably 2 to 12 bar, more preferably 2 to 8 bar. 35. The method according to any of the preceding embodiments, in which pyrolysis is carried out in step (d) for a period of 1 to 90 minutes, preferably 1.5 to 5 minutes. 36. The method according to any of the preceding embodiments, wherein the ratio of the volumetric capacity of the first pyrolysis reactor to the second pyrolysis reactor is at most 10:3, preferably in the range of 10:0.2 to 10:2, more preferably from 10:1 to 10:2. 37. The method according to any of the preceding embodiments, wherein the second pyrolysis product comprises a solid, a gas and / or a liquid. 38. The method according to embodiment 37, wherein the amount of gas is at least 10% by weight, preferably at least 20% by weight, more preferably at least 40% by weight, based on the total weight of the second pyrolysis product. 39. The method according to embodiment 37 or 38, wherein the gas comprises a carbon fraction of at least 5% by weight, preferably at least 15% by weight, more preferably at least 20% by weight, in particular at least 40% by weight, based on the total weight of the gas. 40. The method according to embodiment 39, wherein the carbon fraction comprises methane, ethane, ethene, propane, propene, butane, butene, butadiene, or a mixture of these components. 41. The method according to any of the embodiments from 37 to 40, wherein the liquid comprises an oil, preferably wherein the oil comprises a light oil and a heavy oil. 42. The method according to embodiment 41, wherein the light oil preferably comprises a carbon fraction of 3 to 14 atoms of Petition 870250083713, dated 09 / 17 / 2025, page 26 / 43 21 / 25 carbon per molecule and / or where the heavy oil preferably comprises a carbon fraction of 11 to 50 carbon atoms per molecule. 43. The method according to any of the embodiments from 37 to 42, wherein the amount of solid is at most 70% by weight, preferably at most 55% by weight, more preferably at most 30% by weight, based on the total weight of the second pyrolysis product. 44. The method according to any of the embodiments from 37 to 43, wherein the solid comprises an inorganic salt, a ceramic raw material, an asphaltene, a tar and / or a coke. 45. The method according to any of the embodiments in 37 to 44, further comprising step (e): separating at least a portion of the solid from the second pyrolysis product. 46. ​​The method according to embodiment 45, wherein the separation in step (e) comprises gravimetric separation, filtration and / or centrifugal separation, preferably filtration. 47. The method according to embodiment 46, in which filtration comprises separation with a filter medium containing activated carbon or bleaching earth. 48. The method according to any of the embodiments in 45 to 47, wherein the solid is dried after step (e), preferably at a temperature in the range of 50 to 250°C, more preferably 100 to 200°C, in particular 130 to 160°C; and / or for a period of up to 120 min, preferably 5 to 60 min. 49. The method according to any of the modalities from 37 to 48, in which the gas and / or liquid are separated by fractional distillation. 50. The method according to embodiment 49, in which the gas and / or liquid are separated into individual components by means of Petition 870250083713, dated 09 / 17 / 2025, page 27 / 43 22 / 25 fractional distillation. 51. A device for the pyrolysis of a plastic, in particular a plastic waste, with a method according to one of the embodiments from 1 to 50, comprising a first pyrolysis reactor for the pyrolysis of the plastic, a first separation unit for separating the pyrolysis residue from the first pyrolysis product, a second separation unit for separating the pyrolysis residue into the low solids fraction and the high solids fraction, and a second pyrolysis reactor for the pyrolysis of the high solids fraction. 52. The device according to embodiment 50, which further comprises a feeding device for adding a diluent to the plastic prior to pyrolysis in the first pyrolysis reactor. 53. The device according to embodiment 50 or 52, wherein the first pyrolysis reactor and / or the second pyrolysis reactor is / are a screw conveyor reactor, a fluidized bed reactor, a rotary tube reactor or a coke oven, preferably a coke oven. 54. The device according to any of the embodiments in 51 to 53, wherein the first separation unit comprises an evaporator, a cyclone and / or a hydrocyclone, in particular a hydrocyclone. 55. The device according to any of the embodiments in 51 to 54, wherein the second separation unit comprises a gravimetric separation device, a filter, a centrifuge and / or a hydrocyclone, preferably a hydrocyclone. 56. The device according to embodiment 55, wherein the second separation unit comprises the hydrocyclone in combination with the filter or device for gravimetric separation, wherein the hydrocyclone is preferably upstream of the filter or device for Petition 870250083713, dated 09 / 17 / 2025, p. 28 / 43 23 / 25 gravimetric separation. 57. The device according to any of the embodiments in 51 to 56, which further comprises a solid separation device for separating at least a portion of a solid from the second pyrolysis product. 58. The device according to any of the embodiments in 51 to 57, which further comprises a distillation apparatus for separating a gas and / or a liquid from the second pyrolysis product.

[0048] The invention is explained in greater detail below with reference to the descriptions of the figures of some embodiments, to which the invention is not limited in any way.

[0049] FIG. 1 shows a flowchart of a method for the pyrolysis of a plastic.

[0050] As can be seen in FIG. 1, a plastic comprising at least 50% by weight of a polyolefin is fed to an extruder 1, in which the plastic is plasticized and degassed. The plasticized plastic has a temperature of at least 120°C and is then added to a static mixer 2. In the static mixer 2, a diluent 3 may be added to the plasticized plastic to reduce its viscosity. Alternatively or in addition to diluent 3, a portion of a liquid fraction 4 separated from the first pyrolysis product 6 may be mixed with the plasticized plastic to reduce its viscosity. The resulting mixture is then fed to a first pyrolysis reactor 5, in which the plastic is subjected to pyrolysis at a temperature of 350 to 700°C. As a result, a first pyrolysis product 6 comprising a gaseous fraction, a liquid fraction and a pyrolysis residue is obtained.The first pyrolysis product 6 is fed to a first separation unit 7, which comprises a hydrocyclone and is connected downstream of the first pyrolysis reactor 5. Firstly, the gaseous fraction is at least partially separated in the hydrocyclone. A. Petition 870250083713, dated 09 / 17 / 2025, page 29 / 43 24 / 25 The separated portion of the gaseous fraction 8 can then be further separated into a light oil (e.g., with a boiling range of 35 to 225°C) and a heavy oil (e.g., with a boiling range of 225 to 410°C) (not shown). Furthermore, the liquid fraction is at least partially separated in the hydrocyclone. The separated portion of the liquid fraction 4 can be discharged through an outlet 9 of the hydrocyclone and reused in the plastic viscosity reduction method as described above. At least a portion of the pyrolysis residue, comprising at least partially the pyrolysis residue, is discharged through an outlet 10 disposed in the lower portion of the hydrocyclone.

[0051] As can also be seen in FIG. 1, the pyrolysis residue discharged from outlet 10 is fed to a second separation unit 11, which has a hydrocyclone 12 and a filter 13, where it is separated into a low-solids fraction 14 and a high-solids fraction 15. The low-solids fraction has a liquid proportion in the range of 80 to 100% by weight, based on the total weight of the low-solids fraction; and / or the high-solids fraction has a liquid proportion in the range of 50 to 95% by weight, based on the total weight of the high-solids fraction. The low-solids fraction 14 can be reused in the method by adding at least a portion of the low-solids fraction 14 to the plasticized plastic in mixer 2 to reduce viscosity.The fraction with a high solids content 15 is then subjected to pyrolysis in a second pyrolysis reactor 16 at a temperature in the range of 500 to 700°C, the temperature in the second pyrolysis reactor 16 being at least 80°C higher than in the first pyrolysis reactor 5, in order to obtain a second pyrolysis product 17. At least a portion of the solid is separated from the second pyrolysis product 17 by means of a solids separation device 18 having a filter. In this... Petition 870250083713, dated 09 / 17 / 2025, pp. 30 / 43 In the 25 / 25 case, a filter medium comprises activated carbon. The separated portion of the solid 19 is dried in an oven 20 at a temperature of 100 to 200°C. Subsequently, the individual components can be separated from the solid and reused (not shown). The remaining portion of the second pyrolysis product is separated into a gas 22 and a liquid 23 in a distillation apparatus 21 by means of fractional distillation, or it can also be separated into one or more components of a gas and / or one or more components of a liquid.

Claims

1. A method for the pyrolysis of a plastic, in particular of a plastic waste, characterized in that it comprises the steps: (a) pyrolysis of the plastic in a first pyrolysis reactor to obtain a first pyrolysis product, (b) separation of a pyrolysis residue from the first pyrolysis product in a first separation unit, (c) separation of the pyrolysis residue into a low solids fraction and a high solids fraction in a second separation unit, and (d) pyrolysis of the high solids fraction in a second pyrolysis reactor to obtain a second pyrolysis product.

2. Method according to claim 1, characterized in that the pyrolysis residue separated in step (b) has a boiling point of at least 250°C.

3. A method according to claim 1 or 2, characterized in that the low-solids fraction has a liquid proportion in the range of 80 to 100% by weight, based on the total weight of the low-solids fraction; and / or in that the high-solids fraction has a liquid proportion in the range of 50 to 95% by weight, based on the total weight of the high-solids fraction.

4. Method according to any one of claims 1 to 3, characterized in that the separation in the second separation unit in step (c) comprises centrifugal separation.

5. Method according to claim 4, characterized in that the separation in the second separation unit in step (c) comprises centrifugal separation in combination with filtration or gravimetric separation.

6. Method, according to any of the claims Petition 870250083713, dated 09 / 17 / 2025, page 32 / 43 2 / 3 1 to 5, characterized in that the ratio of the volumetric capacity of the first pyrolysis reactor and the second pyrolysis reactor is at most 10:

3.

7. A method according to any one of claims 1 to 6, characterized in that the second pyrolysis product comprises a solid, a gas and / or a liquid.

8. Method according to claim 7, characterized in that the gas comprises a carbon fraction of at least 20% by weight, based on the total weight of the gas.

9. Method according to claim 7 or 8, characterized in that the amount of solid is at most 70% by weight, based on the total weight of the second pyrolysis product.

10. Method according to any one of claims 1 to 9, characterized in that it further comprises step (e): separating at least a portion of the solid from the second pyrolysis product.

11. Method according to claim 10, characterized in that the separation in step (e) comprises filtration, preferably with a filter medium containing activated carbon or bleaching earth.

12. Device for the pyrolysis of plastic, in particular a plastic waste, with the method according to any one of claims 1 to 11, characterized in that it comprises a first pyrolysis reactor (5) for the pyrolysis of the plastic, a first separation unit (7) for separating the pyrolysis residue from the first pyrolysis product, a second separation unit (11) for separating the pyrolysis residue into the low solids fraction and the high solids fraction, and a second pyrolysis reactor (16) for the pyrolysis of the high solids fraction.

13. Device according to claim 12, characterized in that the second separation unit (11) comprises a hydrocyclone (12).

14. Device according to claim 13, characterized in that the second separation unit (11) comprises the hydrocyclone (12) in combination with a filter (13) or a device for gravimetric separation.

15. Device according to any one of claims 12 to 14, characterized in that it further comprises a solid separation device (18) for separating at least a portion of a solid from the second pyrolysis product.

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