MÉTODO PARA A EXTRAÇÃO DE UMA CERA DE UM RESÍDUO DA PIRÓLISE

Abstract

The invention relates to a method for extracting a wax from a pyrolysis residue, comprising the steps of (a) providing the pyrolysis residue, wherein the pyrolysis residue comprises the wax, (b) mixing the pyrolysis residue with a solvent at at least 30°C to obtain a mixture, wherein the wax is at least partially dissolved in the solvent, (c) cooling the mixture to crystallise at least one portion of the dissolved wax, (d) separating at least one portion of the crystallised wax from the mixture.

Description

[0001] The invention relates to a method for obtaining a wax from a pyrolysis residue.

[0002] It is known from the prior art to separate a wax from a starting product by means of crystallization. For example, US patent document 2002 / 0096451 A1 describes a method for purifying a petroleum product. A solvent is added to the petroleum product at room temperature. The resulting mixture is then cooled to crystallize and separate a wax contained in the petroleum product.

[0003] A similar method for dewaxing is disclosed in patent document WO 2021 / 115982 A1, where a solvent is added at room temperature to a pyrolysis residue obtained from the pyrolysis of a plastic. The resulting mixture is then cooled to separate a wax contained therein by means of crystallization.

[0004] Other methods related to wax separation are known from patent documents US 3,720,599 A, US 5,006,222 A, US 2,614,065 A, WO 2017 / 168165 A1 and WO 2021 / 115982 A1.

[0005] In methods known in the prior art, the separation of wax serves predominantly the purpose of purifying the starting product. The separated wax may have relatively low purity.

[0006] However, for numerous applications, it may be necessary to use a wax with high purity, which may require more elaborate cleaning of the separated wax. There is a need for simple and inexpensive methods for producing a wax with high purity. An object of the invention consists in providing such a method.

[0007] The method according to the invention for obtaining a wax from a pyrolysis residue comprises the steps of Petition 870250083760, dated 09 / 17 / 2025, p. 14 / 44 2 / 28 provision of pyrolysis residue, wherein the pyrolysis residue comprises wax, mixing the pyrolysis residue with a solvent at least 30°C to obtain a mixture, wherein the wax is at least partially dissolved in the solvent, cooling the mixture to crystallize at least a portion of the dissolved wax, separating at least a portion of the crystallized wax from the mixture.

[0008] The invention is based on the discovery that a pyrolysis residue, in particular a pyrolysis residue obtained through the pyrolysis of plastic, is a valuable source of a wax. By mixing the pyrolysis residue with the solvent at at least 30°C, the wax can dissolve to a great extent or even completely in the solvent and then be separated from the pyrolysis residue with high purity.

[0009] The wax obtained can be a sustainable alternative to wax obtained directly from petroleum.

[00010] The residue from pyrolysis can be obtained by pyrolyzing a plastic, in particular a waste plastic. Pyrolysis can take place in a pyrolysis reactor, preferably at a temperature of 300 to 500°C, in particular 350 to 450°C. As a result, a good balance between the economy and efficiency of the method can be achieved.

[00011] Pyrolysis 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 solid due to catalyst components.

[00012] Pyrolysis can be carried out primarily in the absence of oxygen, particularly in an inert atmosphere, for example, under nitrogen. Due to a lack of oxygen or the exclusion of oxygen, the Petition 870250083760, dated 09 / 17 / 2025, page 15 / 44 3 / 28 Complete combustion can be prevented and a polymer contained in the plastic can be cleaved or depolymerized.

[00013] Within the scope of the invention, it has been demonstrated that it is advantageous if a fraction, preferably a heavy fraction, of the pyrolyzed plastic is used as the pyrolysis residue. In a preferred embodiment, the pyrolysis residue is therefore obtained by pyrolyzing a plastic and separating at least one fraction, preferably a gaseous fraction, from the pyrolyzed plastic. The separated fraction preferably has a lower boiling point (or a lower boiling range) than the pyrolysis residue.

[00014] In a particularly preferred embodiment, the pyrolysis residue has a boiling point (or a lower end of a boiling range) of at least 100°C, preferably at least 150°C, more preferably at least 200°C, more preferably at least 240°C, more preferably at least 270°C, and most preferably at least 300°C. The pyrolysis residue preferably has a boiling point (or a lower end of a boiling range) in the range of 100°C to 700°C, preferably 150°C to 600°C, more preferably 200°C to 500°C, more preferably 240°C to 460°C, more preferably 270°C to 430°C, and most preferably 300°C to 400°C. It has been found that fractions with such a boiling point can have particularly high proportions of wax and are therefore particularly suitable for the method according to the invention.

[00015] It has proven particularly advantageous if the pyrolysis residue is a melt oil, preferably with a boiling point (or a lower end of a boiling range) in the range of 300°C to 400°C. In this case, the wax content of the pyrolysis residue can be, for example, about 50% by weight.

[00016] The boiling point (or boiling range) can be Petition 870250083760, dated 09 / 17 / 2025, p. 16 / 44 4 / 28 preferably determined by ASTM standard D750015:2019. Alternatively, ASTM standard D288722:2022 may be used.

[00017] 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 the polyolefin and / or polystyrene in an amount of at least 65% by weight, more preferably at least 70% by weight, and in particular at least 90% by weight, based on the total weight of the plastic. As a result, a pyrolysis residue may be obtained comprising a significant proportion of an aliphatic hydrocarbon (or a mixture of a plurality of aliphatic hydrocarbons), i.e., a significant proportion of wax.

[00018] 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, and 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 can improve the economics of the method.

[00019] In the course of the invention, it has been found that a high polyethylene (PE) content is particularly advantageous, since a particularly high wax content can be obtained during the pyrolysis of the high-PE content plastic. In a particularly preferred embodiment, the plastic therefore has a PE content of at least 10% by weight, preferably at least 20% by weight, more preferably at least 30% by weight, more preferably at least 40% by weight, more preferably at least 50% by weight, more preferably at least 60% by weight, and even more preferably at least 70% by weight. Petition 870250083760, dated 09 / 17 / 2025, p. 17 / 44 5 / 28

[00020] The plastic may comprise an additional polymer from the group consisting of thermoplastics, duromers and / or elastomers, in particular an acrylonitrile butadiene styrene copolymer (ABS), a polyvinyl chloride (PVC), a polyamide (PA) and / or a polyester.

[00021] Before pyrolysis, 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 in order to plasticize it, more preferably to a temperature of 200 to 500°C, and even more preferably from 400 to 470°C. Then the subsequent pyrolysis can be carried out more energy-efficiently and in a shorter time. In the extruder, the plastic can also be degassed to produce a uniform mass without gas inclusions, so that a homogeneous pyrolysis product can be obtained by subsequent pyrolysis.

[00022] Before pyrolysis, a diluent to reduce viscosity may be added to the plastic, particularly plasticized plastic. The diluent is preferably added to the plastic in an amount of at least 5% by weight, and more preferably at least 9% by weight, based on the total weight of the plastic. The ratio between the plastic and the diluent is preferably at least 1:4, and preferably at least 1:9. With the addition of the diluent to the plastic, the mobility of the polymer chains can be increased at a given temperature, so that the heat input into the plastic can be improved during pyrolysis. Furthermore, due to the reduction in viscosity, the risk of the plastic overheating in areas of the pyrolysis reactor wall can be reduced, since it is normally heated by a heating device arranged 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.

[00023] With the addition of the thinner to the plastic, its viscosity Petition 870250083760, dated 09 / 17 / 2025, p. 18 / 44 6 / 28 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 diluent 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.

[00024] 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, and 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 at least 150°C, and in particular to a temperature of 200 to 300°C, before being added to the plastic. By increasing the temperature of the plastic and / or the diluent, the diluent can be mixed with the plastic more quickly and efficiently. Subsequent pyrolysis can also be carried out more economically and faster.

[00025] The diluent can be added to the plastic by means of a feeding device. The feeding device may have an insertion device, such as an insertion pump.

[00026] For example, plastic, in particular plasticized plastic, can be fed into a mixer, for example, a static mixer, and mixed there 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 arranged, for example, in the compression zone or in the mixing zone of the extruder.

[00027] The diluent may comprise a hydrocarbon selected from an alkane, a cycloalkane, and / or an aromatic. As a result of pyrolysis, such diluent may be converted into a gaseous and / or liquid product, which may be at least partially separated from Petition 870250083760, dated 09 / 17 / 2025, p. 19 / 44 7 / 28 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 oil obtained from petroleum in an oil refinery, for example, residual oil from a pyrolysis system. The diluent preferably comprises at least a portion of a liquid fraction of the pyrolysis residue. This may be separated, for example, in a hydrocyclone.

[00028] 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 a mixture of plastic and diluent has been introduced 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.

[00029] In addition to the wax and the solid, the pyrolysis residue provided in step (a) of the method may also comprise a liquid fraction. The proportion of the liquid fraction is preferably no more than 95% by weight, more preferably 30 to 95% by weight, in particular 50 to 70% by weight, based on the total weight of the pyrolysis residue. As the proportion of the liquid fraction decreases, the rate at which at least a portion of the wax is dissolved in the solvent may increase, or a smaller amount of solvent may be added to the pyrolysis residue in order to at least partially dissolve the wax in the solvent. As a result, the separation of at least a portion of the wax from the low-solids mixture may also be facilitated. The use of solvents may also be reduced as a consequence.

[00030] In this way, the method can be designed more effectively. Petition 870250083760, dated 09 / 17 / 2025, page 20 / 44 8 / 28

[00031] The pyrolysis residue provided in step (a) of the method can be obtained by pyrolyzing the plastic in a pyrolysis reactor and subsequently increasing the solids concentration of the pyrolysis residue. As a result, the proportion of the liquid fraction of the resulting pyrolysis residue can preferably be reduced to a maximum of 95% by weight, more preferably to 30 to 95% by weight, and in particular to 50 to 70% by weight, based on the total weight of the pyrolysis residue.

[00032] In order to increase the concentration of solids, a hydrocyclone can be used, which can be connected downstream of the pyrolysis reactor.

[00033] If the pyrolysis residue is obtained by pyrolysis of a plastic, a gaseous fraction can be separated from the pyrolysis residue after pyrolysis and before step (a) of the method. The separation of the gaseous fraction can occur by evaporation, for example, in a hydrocyclone, which can be connected downstream of the pyrolysis reactor.

[00034] The separation of the gaseous fraction from the pyrolysis residue and the increase in the concentration of solids from the pyrolysis residue can be carried out, for example, with a single separation device or with a plurality of separation devices connected in series. Advantageously, the separation of the gaseous fraction from the pyrolysis residue and the increase in the concentration of solids from the pyrolysis residue occur in only one step of the method by means of a hydrocyclone, which can be connected downstream of the pyrolysis reactor. Such a hydrocyclone is described in patent document WO 2023 / 036751 A1. By introducing a mixture comprising the pyrolysis residue and the gaseous fraction through an inlet arranged in an upper region of a hydrocyclone casing, a vortex flow can be generated in the hydrocyclone, and as a consequence the gaseous fraction can be separated from the pyrolysis residue and discharged through an outlet. Petition 870250083760, dated 09 / 17 / 2025, p. 21 / 44 9 / 28 arranged in the upper region of the hydrocyclone (e.g., on its roof). The pyrolysis residue can then be discharged towards the bottom of the hydrocyclone due to gravity, where a tangential velocity of a vortex flow that is formed can continuously increase. As a result, at least a portion of the pyrolysis residue, in particular at least a portion of the pyrolysis residue comprising at least partially wax and solid, can be discharged through an outlet arranged at the bottom of the hydrocyclone, while at least a portion of the liquid fraction of the pyrolysis residue passes into an internal container arranged in the hydrocyclone and can be discharged from it through an outlet, for example, for further use as a diluent. The pyrolysis residue discharged through the outlet arranged at the bottom of the hydrocyclone can then be supplied according to step (a) of the method.The hydrocyclone is preferably operated at a temperature in the range of 300 to 450°C, more preferably from 320 to 420°C, and particularly preferably from 360 to 400°C.

[00035] The pyrolysis residue can be cooled before the addition of the solvent, before step (a) of the method, or between steps (a) and (b).

[00036] Cooling can be carried out using a cooling unit. The pyrolysis residue is preferably cooled to a temperature not exceeding 220°C, more preferably not exceeding 200°C, and particularly preferably not exceeding 180°C. Cooling the pyrolysis residue may be necessary in particular if the pyrolysis residue is obtained immediately before processing a plastic (by means of pyrolysis and, if necessary, the subsequent separation of a gaseous fraction from the pyrolysis residue and / or increasing the solids concentration of the pyrolysis residue). Cooling the pyrolysis residue prevents unwanted evaporation and / or decomposition of the solvent during its addition to the pyrolysis residue. Petition 870250083760, dated 09 / 17 / 2025, page 22 / 44 10 / 28 can be reduced or completely prevented. The pyrolysis residue is preferably cooled to a temperature not lower than 30°C, more preferably not lower than 80°C, even more preferably not lower than 100°C, and particularly preferably not lower than 120°C. Further cooling below the indicated temperature may impair the solubility of the wax in the solvent.

[00037] The solvent can be added to the pyrolysis residue by means of an introduction device. The introduction device may have an insertion device, such as an insertion pump. In order to mix the pyrolysis residue with the solvent in step (b) of the method, the pyrolysis residue can be fed into a container to which the introduction device can be connected. The container may be heatable so that the dissolution of the wax in the solvent can occur at a certain temperature.

[00038] The mixing in step (b) of the method preferably takes place at least at 50°C (i.e., at 50°C or more), and more preferably at least at 80°C (i.e., at 80°C or more). A fraction of the wax with a melting point above room temperature (i.e., above 20 to 25°C) can then be dissolved in the solvent. The mixing in step (b) preferably takes place at a temperature in the range of 50 to 200°C, more preferably from 100 to 200°C, even more preferably from 80 to 200°C, and particularly preferably from 80 to 120°C. As a result, the wax can not only be dissolved to a great extent or completely in the solvent, but it can also be ensured that the solvent does not evaporate due to an excessively high temperature.

[00039] Wax can dissolve particularly well in the solvent even at a temperature of 100 to 120°C, whereas a temperature of 120 to 140°C may be ideal in terms of the procedure.

[00040] Mixing in step (b) of the method preferably takes place at a pressure in the range of 1 to 25 bar, and in particular from 5 to 16 bar. Petition 870250083760, dated 09 / 17 / 2025, page 23 / 44 11 / 28

[00041] As a result, the method can also be improved and rapid dissolution of the wax in the solvent can be achieved.

[00042] The solvent preferably has a boiling point (or boiling range) in the range of 20 to 250°C, more preferably 50 to 150°C, and even more preferably 35 to 130°C. The lower the boiling point of the solvent, the lower the temperature at which the wax can be brought to a liquid state.

[00043] Furthermore, as the boiling point of the solvent decreases, the ability of the wax to crystallize during subsequent cooling of the mixture in step (c) of the method may increase, and as a result the yield of wax obtained may be increased.

[00044] The boiling point (or boiling range) of the solvent can be determined using ASTM standard D539909:2017 or ASTM standard D288722:2022.

[00045] The solvent preferably comprises an aliphatic hydrocarbon or a mixture of two or more aliphatic hydrocarbons.

[00046] An impurity that dissolves in the solvent may then remain dissolved when the wax is already crystallizing. In this way, the wax can be separated at a high purity and the impurity may remain in the mixture. The impurity may include an organic impurity comprising nitrogen, oxygen, sulfur, silicon, chlorine, bromine and / or iodine, for example, a heteropolymer (for example, a polyamide, a polyethylene terephthalate, a polyvinyl chloride and / or an acrylonitrile butadiene styrene copolymer) and / or an additive (for example, an anti-aging agent, a plasticizer, a color pigment and / or a flame retardant).

[00047] The solvent preferably comprises at least 10% by weight, preferably at least 20% by weight, and more preferably at least 50% by weight, of the aliphatic hydrocarbon, or a mixture thereof. Petition 870250083760, dated 09 / 17 / 2025, page 24 / 44 12 / 28 of two or more aliphatic hydrocarbons, based on the total weight of the solvent. As the proportion of aliphatic hydrocarbon increases, not only can the solvent's ability to dissolve the wax improve, but the solubility of the solid in the solvent may also be reduced. In the case of a large proportion of an aromatic in the solvent, on the other hand, the solid, in particular an asphaltene or a tar, may dissolve well in the solvent, which may make subsequent separation of the wax more difficult, or as a consequence the separated wax may be contaminated. With a high proportion of a cycloalkane in the solvent, the wax may dissolve well, but the yield may be comparatively low.

[00048] The aliphatic hydrocarbon is preferably selected from the group of aliphatic hydrocarbons that have up to 15 carbon atoms per molecule, and in particular from 4 to 12 carbon atoms per molecule.

[00049] As a result, the method can be carried out efficiently, and a good separation of the wax from the low-solids mixture can become possible.

[00050] The aliphatic hydrocarbon is preferably selected from n-pentane, n-hexane, n-heptane, n-octane, an isomer thereof, or a mixture of the above elements (i.e., a mixture comprising n-pentane, n-hexane, n-heptane, n-octane, an isomer of these alkanes and / or multiple isomers of these alkanes).

[00051] Since the boiling point of these aliphatic hydrocarbons is in the range of 35 to 130°C, the method can be carried out efficiently and economically. The mixing in step (b) of the method can then preferably take place at 120°C or less, and more preferably at 100°C or less, in order to avoid solvent evaporation. Furthermore, due to the low molecular weight of these solvents, the wax may not only dissolve well in them, but may also have a good tendency to crystallize during cooling. Petition 870250083760, dated 09 / 17 / 2025, page 25 / 44 13 / 28 subsequent in step (c) of the method.

[00052] The solvent preferably comprises at least 10% by weight of an alcohol, and more preferably at least 20% by weight, based on the total weight of the solvent. As a result, a polar impurity can be dissolved in the solvent and thus separated from the wax, which crystallizes when the mixture cools. This can further increase the purity of the wax obtained. The solvent preferably comprises 10 to 30% by weight of alcohol, and more preferably 10 to 20% by weight of alcohol, based on the total weight of the solvent. Particularly preferably, the solvent comprises at least 50% by weight of aliphatic hydrocarbon and 10 to 30% by weight of alcohol.

[00053] As a result, both the non-polar wax and a polar impurity can be well dissolved in the solvent and be well separated from each other during subsequent cooling of the mixture. In general, a wax with high purity can then be obtained.

[00054] The alcohol may preferably be selected from methanol, ethanol, propanol, or a mixture thereof. Propanol is particularly preferred, as it can reduce the adhesion between the wax crystals. This can allow easier separation of the wax from the solvent in step (d) of the method. Furthermore, after washing, the remaining solvents in the wax can be subsequently well separated from the wax during drying of the wax.

[00055] The ratio of pyrolysis residue to solvent in the mixture obtained in step (b) of the method may depend on the melting temperature of the wax. The higher the melting temperature of the wax, the more solvent may be required to dissolve the wax. It is preferable that the ratio of pyrolysis residue to solvent be in the range of 5:1 to 1:5, preferably 2:1 to 3:1, and in particular 1:1. Then the wax can dissolve to a great extent or even completely in the solvent. Petition 870250083760, dated 09 / 17 / 2025, page 26 / 44 14 / 28

[00056] If the pyrolysis residue contains a solid, it may be at least partially separated from the mixture before step (c). Separation of the solid may include filtration, adsorption and / or centrifugation. Preferably, the solid is separated by adsorption. An adsorbent may be added to the pyrolysis residue, which may comprise activated carbon and / or a bleaching clay. As a result, the solid may be separated from the mixture effectively and as completely as possible.

[00057] The solid may comprise an inorganic salt, a raw ceramic 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 oxide, magnesium oxide and / or calcium carbonate. If the pyrolysis residue provided is obtained by pyrolysis of a plastic, the solid may comprise an additive contained in the plastic. For example, the additive may comprise a filler, a color pigment and / or an additive. A person skilled in the art knows which additives are used depending on the respective plastic and the field of application.

[00058] The solid can be dried after being separated from the mixture, for example, in an oven. As a result, the solid can begin to flow freely and thus 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 minutes, and in particular 5 to 60 minutes.

[00059] One or more components can be separated from the solid, in particular from the dried solid, for example, by filtration and / or centrifugation. Separated components can then be reused, for example, as an additive to a plastic.

[00060] The solvent separated during the drying of the solid can be Petition 870250083760, dated 09 / 17 / 2025, p. 27 / 44 15 / 28 reused in step (b) of the method. Before being recycled in the method, the solvent can be purified, preferably by evaporation, in particular rotary evaporation.

[00061] In step (c) of the method, the mixture is cooled to crystallize at least a portion of the wax dissolved in the solvent. The mixture is preferably cooled at a rate of no more than 25°C / min, more preferably no more than 15°C / min, more preferably no more than 10°C / min, more preferably no more than 5°C / min, and most preferably no more than 2°C / min. Cooling preferably occurs at a rate in the range of 0.05 to 25°C / min, more preferably 0.1 to 15°C / min, more preferably 0.2 to 10°C / min, more preferably 0.4 to 5°C / min, and most preferably 0.5 to 2°C / min. Wax crystals can be well formed in this area at a slow cooling rate, which can allow for better mechanical separation. It has also been shown that slow cooling can lead to a clean product.Faster cooling, on the other hand, can lead to increased formation of microcrystals, which are harder to separate mechanically and may also carry more impurities with them.

[00062] Therefore, it is preferable if the cooling in step (c) of the method occurs for a period of at least 5 minutes, more preferably at least 10 minutes, more preferably at least 30 minutes, and most preferably at least 60 minutes. Preferably, the cooling occurs for a period of 5 to 240 minutes, more preferably 10 to 180 minutes, more preferably 30 to 150 minutes, and most preferably 60 to 120 minutes.

[00063] The wax crystals that form may have a scale-like shape which is characteristic of these parameters of the method.

[00064] In step (c) of the method, the mixture is cooled preferably to 10°C or less, more preferably to 0°C or less, and further Petition 870250083760, dated 09 / 17 / 2025, p. 28 / 44 16 / 28 preferably at 10°C or less. Although the wax may initially crystallize during cooling at a slow cooling rate, particularly at a maximum of 5°C / min from, for example, 100 to only 50°C, a relatively large amount of solvent may be included in the wax crystals, which can reduce the purity of the wax, especially since the solvent may also contain an impurity dissolved in it, which may then also be included in the wax crystals. When cooled to a lower temperature (for example, to 10°C or less), solvent inclusion can be reduced or completely prevented, so that the purity of the wax obtained can be significantly increased.

[00065] In step (d) of the method, at least a portion of the crystallized wax can be separated from the mixture.

[00066] Separation may involve filtration and / or centrifugation.

[00067] The temperature during separation is preferably 80°C or less, and more preferably 30°C or less.

[00068] The temperature should preferably be in the range of 10 to 80°C, and in particular from 0 to 30°C. This can prevent the wax from dissolving back into the solvent.

[00069] Furthermore, separation can preferably occur at a pressure of up to 10 bar, and more preferably from 5 to 10 bar.

[00070] This can improve the efficiency of the method.

[00071] After separating the wax from the mixture in step (d) of the method, the solvent contained in the mixture can be at least partially separated from the mixture. The separation can be carried out by evaporation or distillation.

[00072] The separated solvent can be reused in step (b) of the method. Before being recycled in the method, the solvent can be further purified, preferably by evaporation, in particular by Petition 870250083760, dated 09 / 17 / 2025, p. 29 / 44 17 / 28 rotary evaporation.

[00073] The wax separated in step (d) of the method may have a boiling point (or a lower boiling point of a boiling range) preferably of at least 270°C, more preferably at least 300°C, and even more preferably a boiling point (or a boiling range) in the range of 340 to a boiling point of 700°C. The boiling point (or boiling range) of the wax can be determined using ASTM standard D750015:2019 (preferably for a wax with a boiling point or boiling range of 100 to 850°C, and in particular 100 to 735°C) or using ASTM standard D288722:2022 (preferably for a wax with a boiling point or boiling range of 55 to 538°C).

[00074] The separated wax preferably has at least 15 carbon atoms per molecule, more preferably at least 20, and in particular at least 40. The wax preferably has from 20 to 80 carbon atoms per molecule, and in particular from 20 to 65. Such waxes are well suited for further use.

[00075] Separated wax can be supplied to a refinery processing plant, in particular a fluid catalytic cracking (FCC) plant, a thermal gas unit (TGU plant), a hydrogenation plant and / or a coke oven. Separated wax can also be used in other technical areas, for example, as a lubricant and / or additive. Separated wax can be reprocessed before further use.

[00076] For example, wax can be purified and / or separated into different carbon fractions.

[00077] The separated wax preferably has a proportion of one (or more) carbon fraction of at least 60% by weight, more preferably at least 70% by weight, even more preferably by Petition 870250083760, dated 09 / 17 / 2025, pp. 30 / 44 18 / 28 less than 80% by weight, and in particular at least 85% by weight, based on the total weight of the separated wax. This ratio provides information on the purity of the separated wax, whereby a high proportion of the carbon fraction corresponds to a high purity of the separated wax. By means of the method according to the invention, a wax with a high purity can thus be obtained, which can be further increased by subsequent washing of the wax. The proportion of the carbon fraction can be determined by means of gravimetric analysis, wherein the gravimetric analysis may comprise a determination of the masses of the pyrolysis residue, the added solvent and the separated wax.

[00078] The separated wax can be washed off after step (d) of the method.

[00079] In particular, the wax can be washed off one to three times.

[00080] As a result, the purity of the separated wax can be increased even further.

[00081] During washing, the wax temperature is preferably 80°C or less, more preferably 30°C or less, even more preferably in the range of 10 to 80°C, and in particular 0 to 30°C. This can prevent the wax from dissolving again in the solvent. When the wax is washed, a similar or the same temperature can be selected as when separating the wax in step (d) of the method.

[00082] Preferably, the wax is washed off with alcohol.

[00083] As a result, any remaining polar impurity can be removed by washing, thereby obtaining a wax of particularly high purity. The alcohol used for washing is preferably selected from methanol, ethanol, propanol, or a mixture thereof. As a result, not only can any remaining polar impurity be effectively removed Petition 870250083760, dated 09 / 17 / 2025, page 31 / 44 19 / 28 by washing, but the solvent remaining in the wax after washing can be subsequently separated well from the wax during drying.

[00084] The method may include an additional step (e): Drying the separated wax. As a result, the solvent separated along with the wax crystals can be removed. Drying can be carried out thermally at high temperature or, alternatively, at low temperature under vacuum. The type of drying may depend on the further use of the wax. In order to maintain the structure of the wax crystals, vacuum drying is preferred. If the wax is subsequently used in liquid form, it can also be dried at a high temperature and, if necessary, melted. Thermal drying is preferably carried out at a temperature of 150°C or less and at ambient pressure (0.7 to 1.1 bar). Vacuum drying preferably occurs at a temperature of 30°C or less, and at a pressure of 750 mbar or less, and in particular at 500 mbar or less. The solvent separated during wax drying can be reused in step (b) of the method.Before being recycled in the method, the solvent can be further purified, preferably by evaporation, in particular rotary evaporation.

[00085] The invention relates in particular to the following embodiments:

[00086] 1. A method for obtaining a wax from a pyrolysis residue, which comprises the steps of (a) providing the pyrolysis residue, wherein the pyrolysis residue comprises wax, (b) mixing the pyrolysis residue with a solvent at least 30°C to obtain a mixture, wherein the wax is at least partially dissolved in the solvent, (c) cooling the mixture to crystallize at least a portion of the dissolved wax, Petition 870250083760, dated 09 / 17 / 2025, pp. 32-44 20 / 28 (d) separation of at least a portion of the crystallized wax from the mixture.

[00087] 2. The method according to embodiment 1, in which the pyrolysis residue is obtained by pyrolysis of a plastic, in particular a waste plastic.

[00088] 3. The method according to any of the preceding embodiments, in which the pyrolysis residue is obtained by pyrolyzing a plastic and separating at least one fraction, preferably a gaseous fraction, from the pyrolyzed plastic.

[00089] 4. The method according to any of the preceding embodiments, wherein the pyrolysis residue has a boiling point of at least 100°C, preferably at least 150°C, more preferably at least 200°C, more preferably at least 240°C, more preferably at least 270°C, and most preferably at least 300°C.

[00090] 5. The method according to any of the preceding embodiments, wherein the pyrolysis residue has a boiling point in the range of 100°C to 700°C, preferably 150°C to 600°C, more preferably 200°C to 500°C, more preferably 240°C to 460°C, more preferably 270°C to 430°C, and most preferably 300°C to 400°C.

[00091] 6. The method according to any of the preceding embodiments, wherein the plastic comprises a polyolefin and / or a polystyrene (PS), wherein the polyolefin may comprise a polyethylene (PE) and / or a polypropylene (PP).

[00092] 7. The method according to embodiment 6, 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. Petition 870250083760, dated 09 / 17 / 2025, pp. 33 / 44 21 / 28

[00093] 8. The method according to any of the preceding embodiments, wherein the plastic has a PE content of at least 10% by weight, preferably at least 20% by weight, more preferably at least 30% by weight, more preferably at least 40% by weight, more preferably at least 50% by weight, more preferably at least 60% by weight, and even more preferably at least 70% by weight.

[00094] 9. The method according to any of the preceding embodiments, in which the pyrolysis residue is cooled to a temperature not higher than 220°C, more preferably not higher than 200°C, and particularly preferably not higher than 180°C, before the addition of the solvent.

[00095] 10. The method according to any of the preceding embodiments, in which the pyrolysis residue is cooled to a temperature not lower than 30°C, more preferably not lower than 80°C, even more preferably not lower than 100°C, and especially preferably not lower than 120°C, before the addition of the solvent.

[00096] 11. The method according to any of the preceding embodiments, wherein the mixing in step (b) takes place at least 50°C, more preferably at least 80°C, in particular in the range of 50 to 200°C, preferably 100 to 200°C, more preferably 80 to 200°C, and in particular 80 to 120°C.

[00097] 12. The method according to any of the preceding embodiments, wherein the mixing in step (b) takes place at a pressure of 1 to 25 bar, preferably 5 to 16 bar.

[00098] 13. The method according to any of the preceding embodiments, wherein the solvent has a boiling point in the range of 20 to 250°C, preferably 50 to 150°C, and more preferably 35 to 130°C. Petition 870250083760, dated 09 / 17 / 2025, pp. 34 / 44 22 / 28

[00099] 14. The method according to any of the preceding embodiments, wherein the solvent comprises an aliphatic hydrocarbon. [000100] 15. The method according to any of the preceding embodiments, wherein the solvent comprises at least 10% by weight, preferably at least 20% by weight, and more preferably at least 50% by weight, of the aliphatic hydrocarbon, based on the total weight of the solvent. [000101] 16. In the method according to embodiment 14 or 15, the aliphatic hydrocarbon is selected from the group of aliphatic hydrocarbons that have up to 15 carbon atoms per molecule, and preferably 4 to 12 carbon atoms per molecule. [000102] 17. The method according to any of the embodiments in 16, the aliphatic hydrocarbon is selected from n-pentane, n-hexane, n-heptane, n-octane, an isomer thereof, or a mixture of the above elements. [000103] 18. The method according to any of the preceding embodiments, wherein the solvent comprises at least 10% by weight of an alcohol, and preferably at least 20% by weight, based on the total weight of the solvent. [000104] 19. The method according to embodiment 18, wherein the solvent comprises 10 to 30% by weight of alcohol, and preferably 10 to 20% by weight of alcohol, based on the total weight of the solvent. [000105] 20. The method according to any of the embodiments in 19, wherein the solvent comprises at least 50% by weight of aliphatic hydrocarbon and 10 to 30% by weight of alcohol, based on the total weight of the solvent. [000106] 21. The method according to any of the embodiments in 20, wherein the alcohol is selected from methanol, ethanol, propanol, or a mixture thereof, in particular propanol. Petition 870250083760, dated 09 / 17 / 2025, pp. 35 / 44 23 / 28 [000107] 22. The method according to any of the preceding embodiments, in which the ratio between the pyrolysis residue and the solvent in the mixture obtained in step (b) is in the range of 5:1 to 1:5, preferably 2:1 to 3:1, and in particular is 1:1. [000108] 23. The method according to any of the preceding embodiments, in which a solid contained in the pyrolysis residue is separated at least partially from the mixture before step (c). [000109] 24. The method according to embodiment 23, wherein the solid comprises an inorganic salt, a raw ceramic material, an asphaltene, a tar and / or a coke. [000110] 25. The method according to embodiment 23 or 24, in which the separation of the solid comprises filtration, adsorption and / or centrifugation. [000111] 26. The method according to embodiment 25, wherein the separation of the solid comprises adsorption, in which an adsorbent is added to the pyrolysis residue, and wherein the adsorbent preferably comprises an activated carbon and / or a bleaching clay. [000112] 27. The method according to any of the embodiments in 26, wherein the separated solid is dried, preferably at a temperature of 50 to 250°C, and more preferably of 100 to 200°C, and / or for a period of up to 120 minutes, and preferably of 5 to 60 minutes. [000113] 28. The method according to any of the preceding embodiments, wherein in step (c), the mixture is cooled to 10°C or less, preferably to 0°C or less, and more preferably to 10°C or less. [000114] 29. The method according to any of the preceding embodiments, wherein the mixture is cooled in step (c) at a rate of no more than 25°C / min, preferably no more than 15°C / min, more preferably no more than 10°C / min, more preferably no more than 5°C / min, more preferably no more than 2°C / min, of Petition 870250083760, dated 09 / 17 / 2025, pp. 36 / 44 24 / 28 preference in the range of 0.05 to 25°C / min, with more preference from 0.1 to 15°C / min, with more preference from 0.2 to 10°C / min, with more preference from 0.4 to 5°C / min, and with greater preference from 0.5 to 2°C / min. [000115] 30. The method according to any of the preceding embodiments, wherein the cooling in step (c) occurs for a period of at least 5 minutes, more preferably at least 10 minutes, more preferably at least 30 minutes, more preferably at least 60 minutes, preferably for a period of 5 to 240 minutes, more preferably from 10 to 180 minutes, more preferably from 30 to 150 minutes, and most preferably from 60 to 120 minutes. [000116] 31. The method according to any of the preceding embodiments, in which the separation of the crystallized wax in step (d) comprises filtration and / or centrifugation. [000117] 32. The method according to any of the preceding embodiments, wherein the temperature in step (d) is 80°C or less, preferably 30°C or less, more preferably in the range of 10 to 80°C, and in particular from 0 to 30°C. [000118] 33. The method according to any of the preceding embodiments, wherein the solvent is separated at least partially from the mixture after step (d), wherein the separated solvent is preferably reused in step (b). [000119] 34. The method according to any of the preceding embodiments, wherein the separated wax has a boiling point of at least 270°C, preferably at least 300°C, and more preferably a boiling point in the range of 340 to 700°C. [000120] 35. The method according to any of the preceding embodiments, wherein the wax has at least 15 carbon atoms per molecule, preferably at least 20, and in particular at least 40. [000121] 36. The method according to embodiment 35, wherein the wax has from 20 to 80 carbon atoms per molecule, and preferably Petition 870250083760, dated 09 / 17 / 2025, pp. 37 / 44 25 / 28 from 20 to 65. [000122] 37. The method according to any of the preceding embodiments, wherein the separated wax has a carbon fraction proportion of at least 60% by weight, preferably at least 70% by weight, more preferably at least 80% by weight, and in particular at least 85% by weight, based on the total weight of the separated wax. [000123] 38. The method according to any of the preceding embodiments, in which the separated wax is washed after step (d), preferably with an alcohol, in particular selected from methanol, ethanol, propanol or a mixture thereof. [000124] 39. The method according to any of the preceding embodiments, in which the temperature during washing of the separated wax is 80°C or less, preferably 30°C or less, more preferably in the range of 10 to 80°C, and in particular from 0 to 30°C. [000125] 40. The method according to any of the preceding embodiments, wherein step (e) also comprises: drying the wax separately. [000126] 41. The method according to embodiment 40, in which the wax in step (e) is dried at a temperature of 150°C or less and at a pressure of 0.7 to 1.1 bar. [000127] 42. The method according to embodiment 40 or 41, wherein in step (e) the wax is dried at a temperature of 30°C or less and at a pressure of 750 mbar or less, and preferably 500 bar or less. [000128] 43. The method according to any of the embodiments in 42, wherein the solvent separated during the drying of the wax in step (e) is reused in step (b). [000129] FIGURE 1 shows a flowchart of a pyrolysis method in which wax is obtained from a pyrolysis residue. Petition 870250083760, dated 09 / 17 / 2025, pp. 38 / 44 26 / 28 [000130] As can be seen from FIGURE 1, a plastic comprising at least 50% by weight of a polyolefin is fed into an extruder 1, where 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 in order to reduce its viscosity. Alternatively or in addition to diluent 3, a portion of a liquid fraction 4 separated from a pyrolysis residue may be mixed with the plasticized plastic to reduce its viscosity. The resulting mixture is then fed into a pyrolysis reactor 5, in which the plastic is pyrolyzed at a temperature of 350 to 450°C. As a result, a pyrolysis product 6 is obtained comprising a gaseous fraction and a pyrolysis residue, wherein the pyrolysis residue comprises a liquid fraction, a wax, and a solid.The pyrolysis product 6 is fed into a hydrocyclone 7 downstream of the pyrolysis reactor 5. First, the gaseous fraction is separated at least partially in the hydrocyclone 7. The separated portion of the gaseous fraction 8 can then be further separated as 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). Additionally, the liquid fraction is separated at least partially in the hydrocyclone 7. The separated portion of the liquid fraction 4 can be discharged through an outlet 9 of the hydrocyclone 7 and reused in the method for reducing the viscosity of the plastic, as described above. A portion of the pyrolysis residue, comprising at least partially wax and solid, is discharged through an outlet 10 arranged at the bottom of the hydrocyclone 7. [000131] As can also be seen in FIGURE 1, the pyrolysis residue discharged through outlet 10 is fed into a first cooling unit 11 to cool to a temperature at Petition 870250083760, dated 09 / 17 / 2025, pp. 39 / 44 27 / 28 range of 80 to 240°C. Then, a solvent 13 comprising at least 20% by weight of an aliphatic hydrocarbon is added to the pyrolysis residue in a container 12 by means of an introduction device 14 in order to obtain a mixture in which the wax is at least partially dissolved in the solvent 13. The aliphatic hydrocarbon is selected from the group of aliphatic hydrocarbons that have 4 to 12 carbon atoms per molecule. The mixture obtained has a ratio between the pyrolysis residue and the solvent in the range of 2:1 to 3:1. The container 12 is heated so that dissolution can occur at a temperature in the range of 80 to 200°C. In a separation device 15, the solid is at least partially separated from the mixture by adsorption onto an activated carbon. The separated solid 16 is then dried in an oven 17 at a temperature in the range of 100 to 200°C.After the separated solid 16 has dried, individual components can be separated from the solid and reused (not shown). The solvent 13 separated during drying is reused in step (b) of the method by being returned to the container 12 through the introduction device 14. Before being recycled, the solvent 13 can be purified, for example, by evaporation (not shown). According to FIGURE 1, the mixture is then cooled in a second cooling unit 18 at a rate of no more than 5°C / min to -10°C or less, in order to crystallize at least a portion of the wax dissolved in the solvent. Then, at least a portion of the crystallized wax is separated from the mixture by means of a filter 19. The solvent 13 contained in the mixture is separated in an evaporator 20 and returned analogously to the container 12 through the introduction device 14. [000132] As is also apparent from FIGURE 1, the separated wax 21 is washed in a washer 22 using alcohol for washing. The washed separated wax 21 is then fed into a dryer 23 to dry the wax crystals. The resulting wax 24 can then be placed Petition 870250083760, dated 09 / 17 / 2025, pages 40 / 44 28 / 28 in more use (not shown). [000133] The solvent 13 separated during the drying of the separated wax 21 is also returned to the container 12 through the introduction device 14. Before being recycled, the solvent 13 can be purified, for example, by evaporation (not shown).

Claims

1. Method for obtaining a wax from a pyrolysis residue, characterized in that it comprises the steps of (a) providing the pyrolysis residue, wherein the pyrolysis residue comprises the wax, (b) mixing the pyrolysis residue with a solvent at least 30°C to obtain a mixture, wherein the wax is at least partially dissolved in the solvent, (c) cooling the mixture to crystallize at least a portion of the dissolved wax, (d) separating at least a portion of the crystallized wax from the mixture.

2. Method according to claim 1, characterized in that the mixing in step (b) takes place at at least 80°C.

3. Method according to claim 1 or 2, characterized in that the solvent has a boiling point in the range of 35 to 130°C.

4. A method according to any one of claims 1 to 3, characterized in that the solvent comprises at least 50% by weight of an aliphatic hydrocarbon.

5. Method according to claim 4, characterized in that the aliphatic hydrocarbon is selected from n-pentane, n-hexane, n-heptane, n-octane, an isomer thereof, or a mixture of the above elements.

6. A method according to any one of claims 1 to 5, characterized in that the solvent comprises at least 10% by weight of an alcohol.

7. Method according to claim 6, characterized in that the alcohol is propanol. Petition 870250083760, dated 09 / 17 / 2025, pp. 42 / 44 2 / 2 8. Method according to any one of claims 1 to 7, characterized in that a solid contained in the pyrolysis residue is separated at least partially from the mixture before step (c), preferably wherein the separation of the solid comprises an adsorption in which an adsorbent is added to the pyrolysis residue, and wherein the adsorbent preferably comprises an activated carbon and / or a bleaching clay.

9. Method according to any one of claims 1 to 8, characterized in that the mixture is cooled in step (c) at a rate of no more than 5°C / min.

10. Method according to any one of claims 1 to 9, characterized in that the mixture is cooled in step (c) to 10°C or less.

11. Method according to any one of claims 1 to 10, characterized in that the separation of the crystallized wax in step (d) comprises filtration and / or centrifugation.

12. Method according to any one of claims 1 to 11, characterized in that the temperature in step (d) is 80°C or less.

13. Method according to any one of claims 1 to 12, characterized in that the separated wax has a boiling point of at least 270°C.

14. Method according to any one of claims 1 to 13, characterized in that it also comprises step (e): drying the separated wax.

15. Method according to any one of claims 1 to 14, characterized in that solvent separated during wax drying in step (e) is reused in step (b).

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