Method for obtaining wax from pyrolysis residue

Abstract

The present invention relates to a method for obtaining wax from pyrolysis residue, comprising the steps of: (a) providing pyrolysis residue comprising wax and a solid material, wherein the solid material comprises an inorganic salt, a ceramic raw material, asphaltene, tar, and / or coke; (b) adding a solvent to the pyrolysis residue to obtain a high-solids mixture comprising the solid material and the solvent, wherein the wax is at least partially dissolved in the solvent; (c) separating at least a portion of the solid material from the high-solids mixture to obtain a low-solids mixture; and (d) separating at least a portion of the wax from the low-solids mixture. The present invention further relates to a device for obtaining wax from pyrolysis residue using this method.

Description

Technical Field

[0001] The present invention relates to a method and a device for obtaining wax from pyrolysis residues.

Background Art

[0002] Methods for pyrolyzing starting materials, especially plastics, are known in the prior art. The focus is usually on the recovery of products from the gaseous fraction of the pyrolysis products obtained. The pyrolysis residue is produced as waste and is usually used for energy purposes.

[0003] Such a pyrolysis method is disclosed, for example, in JPH09125073A. In this case, waste plastics are pyrolyzed in a pyrolysis reactor to obtain pyrolysis products containing a gaseous fraction and a pyrolysis residue. The gaseous fraction is cooled and condensed into a product oil. Various fractionated oils can be obtained from this product oil by distillation. A solvent, which can be the product oil or a fractionated oil, is added to the pyrolysis residue. Alternatively, kerosene, light oil, heavy oil, benzene, toluene, or xylene can be used as the solvent. A part of the pyrolysis residue should dissolve in the solvent, thereby making it possible to separate the solid coke-containing fraction contained in the pyrolysis residue. Then, the solvent in which a part of the pyrolysis residue has dissolved is recycled to the pyrolysis reactor for new pyrolysis.

[0004] International Publication No. 2023 / 285472 describes a method for the pyrolysis of plastic waste in which the obtained pyrolysis gas is separated from a solid material (such as coke). Then, the pyrolysis gas is condensed to obtain a pyrolysis oil fraction, and then wax is separated therefrom.

[0005] International Publication 2017 / 168165 relates to a method for producing lubricants by the thermal decomposition of plastics. International Publication 2021 / 115982 describes a method for obtaining aliphatic hydrocarbons from a liquid hydrocarbon stream. U.S. Patent Application Publication 2021 / 0332300 covers a method for converting plastic waste into recycled products for use in the polymerization of propylene. International Publication 2009 / 086107 provides a method for converting heavy oil into low-boiling point hydrocarbon products. The subject of U.S. Patent Application Publication 2009 / 0057192 is a method for generating an improved input stream for a dewaxing process. U.S. Patent No. 3,720,599 discloses a method for dewaxing petroleum.

[0006] Despite methods known from the prior art, the utilization of pyrolysis residues, particularly from plastic pyrolysis, remains largely unresolved. Therefore, there is a need for alternative and better methods for recycling such pyrolysis residues. The object of the present invention is to provide such a method. [Overview of the project]

[0007] The present invention relates to a method for obtaining wax from thermal decomposition residue, (a) A step of providing a pyrolysis residue, wherein the pyrolysis residue comprises wax and a solid material, preferably the solid material comprises an inorganic salt, a ceramic raw material, asphaltene, tar, and / or coke. (b) A step of adding a solvent to the pyrolysis residue to obtain a high-solids mixture containing a solid material and a solvent, wherein the wax is at least partially dissolved in the solvent. (c) A step of separating at least a portion of the solid material from the high solid content mixture in order to obtain a low solid content mixture, (d) A step of separating at least a portion of the wax from the low solids mixture. This includes methods.

[0008] This invention is based on the finding that pyrolysis residues, particularly those obtained from the pyrolysis of plastics, are a valuable source of wax. The method according to this invention allows for the acquisition of not only at least a portion of the wax contained in the pyrolysis residue, but also at least a portion of the solid material contained in the pyrolysis residue. Therefore, this method can mitigate environmental impact by reducing greenhouse gas emissions and waste volume. Overall, it can significantly reduce resource consumption and strengthen the circular economy, which can also bring economic benefits. In particular, the resulting wax can be a sustainable alternative to wax obtained directly from petroleum.

[0009] Pyrolysis residue can be obtained by pyrolysis of plastics, particularly waste plastics. Pyrolysis can occur in a pyrolysis reactor, preferably at a temperature of 300-500°C, especially 350-450°C. As a result, a good balance between cost-effectiveness and method efficiency can be achieved.

[0010] Thermal decomposition can be thermal decomposition (i.e., thermal decomposition without the addition of a catalyst) and / or catalytic decomposition (i.e., catalytic decomposition). Thermal decomposition is preferred to avoid contamination of the wax and / or solid material by the catalyst component.

[0011] Pyrolysis can be carried out mainly in the absence of oxygen, especially in an inert atmosphere, for example, under nitrogen. The absence or removal of oxygen can prevent complete combustion, allowing the polymers contained in the plastic to be cleaved or depolymerized.

[0012] The plastic preferably comprises polyolefin and / or polystyrene (PS), and the polyolefin may comprise polyethylene (PE) and / or polypropylene (PP). The plastic preferably contains polyolefin and / or polystyrene in an amount of at least 65% by weight, more preferably at least 70% by weight, and particularly at least 90% by weight, based on the total weight of the plastic. As a result, a pyrolysis residue can be obtained that contains a considerable proportion of aliphatic hydrocarbons (or a mixture of multiple aliphatic hydrocarbons), i.e., a considerable proportion of wax.

[0013] The plastic preferably contains at least 20% by weight, more preferably at least 50% by weight, even more preferably at least 70% by weight, and particularly at least 90% by weight of polyolefin, 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 present invention can be increased, thereby improving the economics of the method. The plastic may include thermoplastics, duromers, and / or elastomers, and further polymers from the group consisting particularly acrylonitrile-butadiene-styrene copolymer (ABS), polyvinyl chloride (PVC), polyamide (PA), and / or polyester.

[0014] Prior to thermal decomposition, the plastic can be plasticized, for example, in a mixer, particularly in an extruder. Preferably, the plastic is heated to a temperature of at least 120°C, more preferably 200-500°C, and even more preferably 400-470°C for plasticization. Subsequent thermal decomposition can then be carried out more energy-efficiently and in a shorter time. In an extruder, the plastic can also be degassed to produce a homogeneous mass free of gaseous components, thereby enabling a homogeneous thermal decomposition product to be obtained by subsequent thermal decomposition.

[0015] Prior to pyrolysis, a diluent to reduce viscosity can be added to the plastic, particularly the plasticizer. 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 ratio of plastic to diluent is preferably at least 1:4, more preferably at least 1:9. Adding the diluent to the plastic can increase the mobility of the polymer chains at a given temperature, thereby improving the heat input to the plastic during pyrolysis. Furthermore, the viscosity reduction reduces the risk of overheating of the plastic in the wall area of ​​the pyrolysis reactor, as it is typically heated by heating devices located near the outer wall of the pyrolysis reactor. The risk of coking of the plastic during pyrolysis can also be reduced by reducing its viscosity.

[0016] By adding a diluent to the plastic, its viscosity can be reduced by at least 30%, more preferably at least 50%, and especially preferably at least 80%, based on the viscosity of the plastic without the diluent, preferably under the same measurement conditions, particularly at temperatures in the range of 180 to 240°C. This can improve the pumpability of the plastic, thereby facilitating its processing.

[0017] When the diluent is added, the plastic is preferably at a temperature of at least 120°C, more preferably 150-300°C, and particularly 200-300°C. Alternatively or additionally, the diluent may be heated to a temperature of at least 120°C, more preferably at least 150°C, and particularly 200-300°C before being added to the plastic. By raising the temperature of the plastic and / or the diluent, the diluent can be mixed with the plastic more quickly and efficiently. Subsequent thermal decomposition can also be carried out more energy-efficiently and quickly.

[0018] The diluent can be added to the plastic by a supply device. The supply device may have a metering device such as a metering pump. For example, the plastic, especially a plasticizer, can be supplied to a mixer, such as a static mixer, where it can be 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 supply device can be located, for example, in the compression zone or mixing zone of the extruder.

[0019] The diluent may include hydrocarbons selected from alkanes, cycloalkanes, and / or aromatics. As a result of pyrolysis, such diluents can be converted into gaseous and / or liquid products, which can be separated at least partially from the pyrolysis residue and reused. The diluent preferably includes at least a portion of the liquid fraction of the pyrolysis residue, which can be separated, for example, in a hydrocyclone. Alternatively or additionally, the diluent may include fractions obtained from crude oil, particularly heavy oil. Heavy oil may be oil obtained from petroleum in a petroleum refinery, for example, residual oil from a pyrolysis plant. The heavy oil preferably has at least 25% by weight of aromatic hydrocarbons based on the total weight of the heavy oil.

[0020] The diluent preferably has a boiling point (or lower end of the boiling point range) of at least 300°C, and more particularly at at least 350°C. As a result, evaporation of the diluent can be prevented immediately after the mixture of plastic and diluent is introduced into the pyrolysis reactor, but evaporation, cleavage, and / or depolymerization of the diluent can only occur with a 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] Within the scope of the present invention, it has been surprisingly found that the addition of a diluent during pyrolysis results in a pyrolysis residue that is particularly rich in wax. This is particularly advantageous in relation to the method according to the present invention, as it still allows for the acquisition of a larger amount of wax.

[0022] Apart from the wax and solid materials, the pyrolysis residue provided in step (a) of the method may also include a liquid fraction. The proportion of the liquid fraction is preferably up to 95% by weight, more preferably 30-95% by weight, and particularly 50-88% by weight, based on the total weight of the pyrolysis residue. As the proportion of the liquid fraction decreases, at least a portion of the wax can be rapidly dissolved by the solvent, or a smaller amount of solvent must be added to the pyrolysis residue to dissolve the wax at least partially in the solvent. As a result, it can also be made easier to separate at least a portion of the wax from the low-solids mixture. Thus, the method can be designed to be more efficient.

[0023] The pyrolysis residue provided in step (a) of this method can be obtained by pyrolysis of the plastic in a pyrolysis reactor, followed by increasing the solid content concentration of the pyrolysis residue. This may be advantageous in reducing the proportion of liquid fraction in the resulting pyrolysis residue to a maximum of 95% by weight, more preferably to 30-95% by weight, and particularly to 50-88% by weight, based on the total weight of the pyrolysis residue. To increase the solid content concentration, a separation device, preferably a hydrocyclone, which can be connected downstream of the pyrolysis reactor, may be used.

[0024] If the pyrolysis residue is obtained by the pyrolysis of plastics, the gaseous fraction can be separated from the pyrolysis residue after pyrolysis and before step (a) of the method. Separation of the gaseous fraction can occur by evaporation, for example, in a hydrocyclone that can be connected downstream of the pyrolysis reactor.

[0025] The separation of gaseous fractions from the pyrolysis residue and the increase in the solid content concentration of the pyrolysis residue can be performed, for example, using one separation device or using multiple separation devices connected in series. Advantageously, both the separation of gaseous fractions from the pyrolysis residue and the increase in the solid content concentration of the pyrolysis residue occur in only one method step by a hydrocyclone that can be connected downstream of the pyrolysis reactor. Such a hydrocyclone is described in International Publication No. 2023 / 036751. By introducing a mixture containing the pyrolysis residue and gaseous fractions through an inlet located in the upper region of the hydrocyclone jacket, a vortex can be generated within the hydrocyclone, thereby separating the gaseous fraction from the pyrolysis residue and discharging it through an outlet located in the upper region of the hydrocyclone (e.g., on its ceiling). The pyrolysis residue can then be discharged by gravity towards the bottom of the hydrocyclone, and the tangential velocity of the formed vortex can be continuously increased. As a result, at least a portion of the pyrolysis residue, particularly a portion of the pyrolysis residue containing at least wax and solid materials, can be discharged through an outlet located at the bottom of the hydrocyclone, while at least a portion of the liquid fraction of the pyrolysis residue can enter an inner container located within the hydrocyclone and be discharged therefrom through the outlet for further use, for example, as a diluent. The pyrolysis residue discharged through the outlet located at the bottom of the hydrocyclone can then be provided according to step (a) of the method. The hydrocyclone is operated at a temperature preferably in the range of 300 to 450°C, more preferably 320 to 420°C, and particularly preferably 360 to 400°C.

[0026] The pyrolysis residue can be cooled either before the addition of the solvent, before step (a) of the process, or between steps (a) and (b). The cooling can be effected by means of a cooling unit. The pyrolysis residue is preferably cooled to a temperature of 240 °C or lower, more preferably 220 °C or lower, particularly preferably 180 °C or lower. Cooling of the pyrolysis residue can be particularly advantageous when the pyrolysis residue is obtained by means of a direct prior processing of the plastic (by pyrolysis and, if appropriate, subsequent separation of the gaseous fraction from the pyrolysis residue and / or increase in the solids concentration of the pyrolysis residue). By cooling the pyrolysis residue, undesired evaporation and / or decomposition of the solvent during its addition to the pyrolysis residue can be reduced or completely prevented. The pyrolysis residue is preferably cooled to a temperature of 80 °C or higher, more preferably 100 °C or higher, particularly preferably 120 °C or higher. If this temperature is not fallen below, this has the advantage that the solubility of the wax in the solvent is better.

[0027] The solvent can be added to the pyrolysis residue in step (b) of the process by means of an introduction device. The introduction device can have a metering device such as a metering pump. To add the solvent, the pyrolysis residue can be fed into a container to which the introduction device can be connected. The container can be heatable so that the dissolution of the wax in the solvent can take place at a specific temperature.

[0028] The wax is preferably dissolved in the solvent at a temperature of at least 80 °C, more preferably at least 100 °C, even more preferably at least 120 °C, even more preferably 140 °C, particularly at least 160 °C. The wax is preferably dissolved at a temperature in the range from 80 to - 240 °C, more preferably from 100 to 160 °C, particularly from 100 to 140 °C. Thereby, on the one hand, the wax can be dissolved well and rapidly in the solvent, and on the other hand, the process can be carried out rapidly and energy-efficiently, so that good process efficiency is ensured. The wax can be dissolved particularly well in the solvent even at a temperature of from 100 to 120 °C, but a temperature of from 120 to 140 °C can be optimal in terms of the procedure.

[0029] The dissolution of the wax in the solvent can preferably occur at a pressure in the range of 1 to 25 bar, particularly in the range of 5 to 16 bar. As a result, this method can be further improved, and rapid dissolution of the wax in the solvent can be achieved.

[0030] The solvent may preferably have a boiling point (or boiling point range) in the range of 20 to 270°C, more preferably 20 to 250°C, even more preferably 35 to 255°C, even more preferably 20 to 200°C, and particularly 50 to 150°C. As a result, the method can be carried out efficiently. In particular, the solvent preferably has a boiling point (or boiling point range upper limit) at least 10°C lower than the boiling point (or lower limit of the boiling point range) of the wax (or at least 30°C lower), and particularly at least 50°C lower. As a result, the wax can be easily separated from the low solids mixture. The boiling point (or boiling point range) of the solvent can be determined using the standards ASTM D5399-09:2017 or ASTM D2887-22:2022.

[0031] The solvent preferably contains at least 10% by weight, more preferably at least 20% by weight, even more preferably at least 50% by weight, even more preferably at least 70% by weight, and particularly at least 90% by weight, of aliphatic hydrocarbons, based on the total weight of the solvent. The solvent preferably consists of aliphatic hydrocarbons or a mixture of two or more aliphatic hydrocarbons. As the proportion of aliphatic hydrocarbons increases, not only can the solvent's ability to dissolve the wax improve, but the solubility of the solid material in the solvent can also decrease. On the other hand, if the proportion of aromatics in the solvent is high, the solid material, particularly asphaltenes or tars, can dissolve well in the solvent, which may make subsequent separation of the wax more difficult, or as a result, the separated wax may be contaminated. If the proportion of cycloalkanes in the solvent is high, the wax can dissolve well, but the yield may be relatively low.

[0032] The aliphatic hydrocarbon is preferably selected from the group consisting of aliphatic hydrocarbons having up to 15 carbon atoms per molecule, and particularly 4 to 12 carbon atoms per molecule. As a result, this method can be carried out efficiently, and it becomes possible to separate the wax well from the low solids mixture.

[0033] The aliphatic hydrocarbon is preferably selected from n-pentane, n-hexane, cyclohexane, n-heptane, isododecane, tetradecane, their isomers, or mixtures thereof. Since the boiling points of these aliphatic hydrocarbons are in the range of 35 to 255°C, this method can be carried out efficiently and economically. Furthermore, the wax can dissolve well in these solvents because of the low molecular weight of these solvents. Preferably, the solvent contains 10 to 80% by weight of aliphatic hydrocarbons having up to 15 carbon atoms per molecule, 10 to 40% by weight of isoparaffin, 10 to 40% by weight of n-paraffin, and 5 to 20% by weight of aromatics. Particularly preferred is that the solvent contains 20 to 30% by weight of aliphatic hydrocarbons having up to 15 carbon atoms per molecule, 20 to 30% by weight of isoparaffin, 20 to 30% by weight of n-paraffin, and 10 to 15% by weight of aromatics. This includes a mixture of two or more aliphatic hydrocarbons having up to 15 carbon atoms per molecule, two or more isoparaffins, two or more n-paraffins, and / or two or more aromatics. In this embodiment, the aliphatic hydrocarbons preferably include n-heptane, n-octane, n-nonane, and / or n-decane, and / or their isomers, and the proportion of these aliphatic hydrocarbons in the solvent is preferably at least 51% by weight, more preferably at least 65% by weight, and even more preferably at least 80% by weight, based on the proportion of all aliphatic hydrocarbons having up to 15 carbon atoms per molecule present in the solvent. In this embodiment, the proportion of cycloalkanes in the solvent is preferably less than 5% by weight, more preferably less than 1% by weight, and even more preferably less than 0.1% by weight, based on the weight of the solvent. The solvent having the above composition preferably has a boiling point range of 25 to 200°C and / or 0.70 to 0.76 g / cm³ at 15°C. 3It has a density of . This solvent is particularly suitable for dissolving wax. A solvent having this composition can also be obtained by the thermal decomposition of plastic waste and can be used for further use in the method according to the present invention.

[0034] The ratio of the thermal decomposition residue to the solvent is preferably in the range of 3:1 to 1:5, more preferably in the range of 1:1 to 1:3. This allows the wax to be dissolved in the solvent quickly and as completely as possible.

[0035] At least a portion of the solid material is separated from the high-solids mixture in step (c) of the method, and this separation may occur by a first separation device. At least partial separation of the solid material yields a low-solids mixture. The solids concentration of the resulting low-solids mixture is preferably up to 30% by weight, more preferably up to 15% by weight, even more preferably up to 5% by weight, even more preferably up to 2% by weight, and even more preferably up to 1% by weight, based on the total weight of the low-solids mixture.

[0036] The separation of solid materials can be carried out by weight separation, filtration, and / or centrifugation from the high-solids mixture. Weight separation may include sedimentation and / or decantation. In particular, separation can be carried out by filtration. Filtration may be carried out using a filter material which may include activated carbon or bleached clay. As a result, polar components (e.g., tar or polyphenols) dissolved in the solvent with the wax can be well separated and adsorbed by the filter material. During filtration, even particles with an average particle size (D50) of less than 100 μm, and especially less than 50 μm, can be easily removed (determined by laser diffraction). Filtration is preferably carried out at high temperatures. Filtration is preferably carried out at temperatures within the range of 80 to 350°C, more preferably 90 to 300°C, even more preferably 100 to 250°C, and most preferably 150 to 180°C. Filtration is also preferable when carried out at a pressure of 5 bar or more, preferably 5 to 20 bar, and more preferably 10 to 20 bar. By increasing the temperature and / or decreasing the pressure, it becomes possible to separate solid materials more efficiently from the high-solids mixture.

[0037] In preferred embodiments, separation of solid materials occurs by sedimentation and subsequent filtration, which preferably occurs at a pressure of 5 bar or more and a temperature in the range of 100 to 250°C, and more preferably at a pressure of 10 bar or more and a temperature in the range of 150 to 180°C. These parameters allow for particularly good separation of solid materials from high-solids mixtures. This separation efficiency can be further improved when the aliphatic hydrocarbon in the solvent is n-heptane, and especially when the solvent is n-heptane.

[0038] The solid material preferably includes inorganic salts, ceramic raw materials, asphaltenes, tar, and / or coke. Particularly preferably, the pyrolysis residue includes coke. This is especially true when the pyrolysis residue is obtained by pyrolysis of a plastic, and subsequently, liquid and / or gaseous fractions are separated from the pyrolysis residue before the pyrolysis residue is provided by step (a) of the method. In particular, the solid material may include talc, iron oxide (e.g., ferric oxide), aluminum oxide, titanium dioxide, magnesium oxide, and / or calcium carbonate. If the provided pyrolysis residue is obtained by pyrolysis of a plastic, the solid material may include additives contained in the plastic. For example, the additives may include fillers, coloring pigments, and / or other additives. Experts know which additives are used depending on the respective plastic and application field.

[0039] After separation from the high-solids mixture, i.e., after step (c) of this method, the solid material can be dried, for example, in an oven. As a result, the solid material can be made free-flowing and thus easier to process. The solid material 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, particularly 5 to 60 minutes.

[0040] One or more components can be separated from a solid material, particularly from a dry solid material, by means of filtration and / or centrifugation, for example. The separated components can then be reused, for example, as an additive to plastics.

[0041] The solvent separated during the drying of the solid material may be reused in step (b) of the method. Before being recycled into this method, the solvent may be further purified, preferably by evaporation, and especially by rotational evaporation.

[0042] The separation of at least a portion of the wax in step (d) of the method may include evaporation or extraction under pressure. The temperature in step (d) is preferably in the range of 50 to 280°C, more preferably 80 to 150°C, and particularly preferably 100 to 130°C. The pressure in step (d) is preferably in the range of 0.1 to 2.5 bar, and preferably 0.5 to 1 bar. As a result, the separation can occur as completely and quickly as possible.

[0043] If the boiling point (or upper end of the boiling range) of the solvent is significantly below the extraction temperature (e.g., at least 10°C or at least 15°C below), the separation preferably includes extraction under pressure, for example, in a hydrocyclone. If the boiling point (or lower end of the boiling range) of the solvent is above the extraction temperature, substantially equal to or slightly below the extraction temperature (e.g., up to 10°C or up to 15°C below), the separation preferably includes evaporation.

[0044] After separating the wax in step (d) of this method, the solvent contained in the low-solids mixture can be reused in step (b). For this purpose, the solvent can be separated from the low-solids mixture, preferably by evaporation, and particularly by rotational evaporation.

[0045] The wax separated in step (d) of this method preferably has a boiling point (or lower end of the boiling point range) of at least 280°C, more preferably at least 300°C, and even more preferably at least 350°C. The wax preferably has a boiling point (or boiling point range) in the range of 280 to 730°C, and more preferably 350 to 700°C. The wax can then be easily separated from the low solids mixture. The boiling point (or boiling point range) of the wax can be determined by standard ASTM D7500-15:2019 (preferably for waxes having a boiling point or boiling point range of 100 to 850°C, particularly 100 to 735°C) or by standard ASTM D2887-22:2022 (preferably for waxes having a boiling point or boiling point range of 55 to 538°C).

[0046] The separated wax preferably has at least 15, more preferably at least 20, and especially at least 40 carbon atoms per molecule. The wax preferably has 20 to 80, and especially 20 to 65 carbon atoms per molecule. Such wax can be readily reused in a refinery as a lubricant and / or additive.

[0047] The separated wax preferably contains at least 0.1% by weight, more preferably at least 5% by weight, and especially at least 10% by weight of solvent, based on the total weight of the wax. This can lower the freezing point of the wax and thus improve the pumpability of the wax. The separated wax preferably contains up to 60% by weight, preferably up to 50% by weight, and more preferably up to 20% by weight of solvent, based on the total weight of the wax. Otherwise, the properties of the wax may be impaired. The separated wax preferably contains 0.1 to 50% by weight, more preferably 0.1 to 20% by weight of solvent, based on the total weight of the wax.

[0048] The separated wax can be supplied to the processing plants of a refinery, particularly fluid catalytic cracking (FCC) plants, steam crackers, hot gas oil units (TGU plants), hydrogenation plants, and / or cokers. Preferably, the wax is supplied to the FCC plant and / or steam cracker. In the steam cracker, the wax can be converted to low molecular weight alkenes (or mixtures of two or more such alkenes), particularly ethenes and / or propenes. This allows for reuse in the production of plastics, particularly polyolefins.

[0049] When supplied to the processing plant, the wax preferably has a temperature of 40°C or higher, more preferably 50°C or higher, more preferably 80°C or higher, and particularly more preferably 100°C or higher, where this temperature is preferably 40°C to 300°C, more preferably 50°C to 280°C, even more preferably 80°C to 200°C, and even more preferably 100°C to 180°C. In this way, stagnation of the wax can be avoided. This can also be advantageous for energy reasons if the separation of at least a portion of the wax from the low-solids mixture has already occurred at a high temperature and a high temperature is also required in the processing plant, because the already heated wax can then be supplied to the processing plant without prior cooling and, if desired, with further heating. The separated wax can be used in other arts, for example, as a lubricant and / or additive. The separated wax can be reprocessed before further use. For example, the wax can be purified and / or separated into different carbon fractions.

[0050] Preferably, the separated wax is mixed with a hydrocarbon stream before being supplied to a refinery processing plant, particularly an FCC plant. The hydrocarbon stream preferably contains gas oil, preferably vacuum gas oil (VGO) and / or bisbreaker gas oil. The hydrocarbon stream preferably has a boiling point (or lower end of boiling range) of 100°C or higher, more preferably 150°C or higher, and even more preferably 200°C or higher. It is particularly preferable that the hydrocarbon stream has a boiling point (or boiling range) in the range of 100 to 400°C, more preferably 150 to 300°C, and even more preferably 150 to 200°C. This can result in optimal rheological properties for further processing of the mixture of wax and hydrocarbon stream. The boiling point (or boiling range) of the hydrocarbon stream can be determined by standard ASTM D7500-15:2019 (preferably for hydrocarbon streams having a boiling point or boiling range of 100 to 850°C, particularly 100 to 735°C) or by standard ASTM D2887-22:2022 (preferably for hydrocarbon streams having a boiling point or boiling range of 55 to 538°C). Preferably, the hydrocarbon stream has a similar number of carbon atoms per molecule as the separated wax (e.g., 10 or more carbon atoms per molecule). The wax can then be well mixed with the hydrocarbon stream. The mixture of wax and hydrocarbon stream preferably contains an amount of wax of 50% by weight or less, more preferably 20% by weight or less, even more preferably 10% by weight or less, particularly preferably 5% by weight or less, and particularly preferably 2% by weight or less, based on the total weight of the mixture. The mixture particularly preferably contains an amount of wax of 0.1 to 2% by weight, based on the total weight of the mixture. This not only allows for the upgrading of the separated wax, but the mixing of the wax with the hydrocarbon stream can also ensure consistent process conditions in the refinery's processing plant, particularly in FCC plants.

[0051] The present invention also relates to a device for obtaining wax from pyrolysis residue using the method according to the present invention, An introduction device for adding a solvent to the pyrolysis residue, A first separation device for separating at least a portion of a solid material from a high-solids mixture, A second separation device for separating at least a portion of the wax from a low-solids mixture, Equipped with, Preferably, the device relates to a cooling unit (11) for cooling the pyrolysis residue, which is positioned upstream of the introduction device (14) before the addition of the solvent.

[0052] The introduction device for adding the solvent may include a metering device such as a metering pump.

[0053] The introduction device can be connected to a container to which the pyrolysis residue can be supplied, thereby allowing the dissolution of the wax into the solvent to occur within this container. The container may be heated so that the wax can dissolve in the solvent at a high temperature.

[0054] The first separation device may comprise a weight separation device, a filter, a cyclone, a hydrocyclone, or a combination thereof, preferably a filter.

[0055] The second separation device may include an evaporator and / or an extraction device.

[0056] This device may further include a dryer, such as an oven, especially a vacuum oven, to dry the solid material after its separation, i.e., after step (c).

[0057] The present invention further relates to a device for obtaining wax from plastics, particularly waste plastics, comprising the aforementioned device (for obtaining wax from pyrolysis residue) and a pyrolysis reactor for pyrolysis of the plastic to obtain pyrolysis residue.

[0058] The device may further include a mixer, particularly an extruder, for plasticizing the plastic before adding it to the pyrolysis reactor.

[0059] The device may also include a supply device for adding a diluent to the plastic, thereby reducing its viscosity, and this supply device is connected upstream of the pyrolysis reactor. If the device has an extruder, the supply device may be connected downstream of the extruder or, in particular, directly located in the extruder in its compression or mixing zone. Alternatively, the device may include a mixer, in particular a static mixer, for mixing the plastic, in particular a plasticizer, with the diluent.

[0060] The present invention relates in particular to the following embodiments.

[0061] 1. A method for obtaining wax from thermal decomposition residue, (a) A step of providing a pyrolysis residue, wherein the pyrolysis residue comprises wax and a solid material, preferably the solid material comprises an inorganic salt, a ceramic raw material, asphaltene, tar, and / or coke. (b) A step of adding a solvent to the pyrolysis residue to obtain a high-solids mixture containing a solid material and a solvent, wherein the wax is at least partially dissolved in the solvent. (c) A step of separating at least a portion of the solid material from the high solid content mixture in order to obtain a low solid content mixture, (d) A step of separating at least a portion of the wax from the low solids mixture. Methods that include...

[0062] 2. The method according to Embodiment 1, wherein the solvent has a boiling point in the range of 20 to 270°C, preferably 20 to 250°C, more preferably 35 to 255°C, and particularly 50 to 150°C.

[0063] 3. The method according to Embodiment 1 or Embodiment 2, wherein the solvent comprises, based on the total weight of the solvent, at least 10% by weight, preferably at least 20% by weight, more preferably at least 50% by weight, even more preferably at least 70% by weight, and particularly at least 90% by weight of aliphatic hydrocarbons.

[0064] 4. The method according to Embodiment 3, wherein the aliphatic hydrocarbon is selected from the group consisting of aliphatic hydrocarbons having up to 15 carbon atoms per molecule, preferably 4 to 12 carbon atoms per molecule.

[0065] 5. The method according to Embodiment 4, wherein the aliphatic hydrocarbon is selected from n-pentane, n-hexane, cyclohexane, n-heptane, isododecane, tetradecane, their isomers, or mixtures thereof.

[0066] 6. The method according to any one of Embodiments 1 to 5, wherein the ratio of the thermal decomposition residue to the solvent is in the range of 3:1 to 1:5, preferably in the range of 1:1 to 1:3.

[0067] 7. The method according to any one of Embodiments 1 to 6, wherein in step (b), the dissolution of the wax in the solvent is carried out at a temperature in the range of at least 80°C, preferably at least 100°C, more preferably at least 120°C, even more preferably at least 140°C, particularly at least 160°C, particularly preferably 80 to 240°C, more preferably 100 to 160°C, and particularly particularly 100 to 140°C.

[0068] 8. The method according to any one of Embodiments 1 to 7, wherein in step (b), the dissolution of the wax in the solvent is carried out at a pressure in the range of 1 to 25 bar, preferably in the range of 5 to 16 bar.

[0069] 9. The method according to any one of Embodiments 1 to 8, wherein the solid material is separated in step (c) by weight separation (particularly sedimentation), filtration, and / or centrifugation, preferably by filtration.

[0070] 10. The method according to Embodiment 9, wherein the solid material is separated in step (c) by filtration, preferably by sedimentation and subsequent filtration, preferably at a temperature in the range of 80 to 350°C, more preferably 90 to 300°C, even more preferably 100 to 250°C, most preferably 150 to 180°C, and / or at a pressure of 5 bar or more, preferably 5 to 20 bar, more preferably 10 to 20 bar.

[0071] 11. The method according to any one of Embodiments 1 to 10, wherein the solid material is dried after step (c) at a temperature preferably 50 to 250°C, more preferably 100 to 200°C, particularly 130 to 160°C, and / or for a maximum of 120 minutes, preferably 5 to 60 minutes.

[0072] 12. The method according to Embodiment 11, wherein the solvent separated during the drying of the solid material is reused in step (b).

[0073] 13. The method according to any one of Embodiments 1 to 12, wherein the separation of at least a portion of the wax in step (d) includes evaporation or extraction under pressure.

[0074] 14. The method according to Embodiment 13, wherein the temperature is in the range of 50 to 280°C, more preferably 80 to 150°C, particularly preferably 100 to 130°C, and / or the pressure is in the range of 0.1 to 2.5 bar, more preferably 0.5 to 1 bar.

[0075] 15. The method according to any one of Embodiments 1 to 14, wherein the solvent contained in the low-solids mixture after step (d) is reused in step (b).

[0076] 16. The method according to any one of Embodiments 1 to 15, wherein the separated wax has a boiling point of at least 280°C, preferably at least 300°C, more preferably at least 350°C, and the separated wax has a boiling point in the range of 280 to 730°C, more preferably in the range of 350 to 700°C.

[0077] 17. The method according to any one of Embodiments 1 to 16, wherein the separated wax has at least 15, preferably at least 20, and particularly at least 40 carbon atoms per molecule, and the wax preferably has 20 to 80, and particularly 20 to 65 carbon atoms per molecule.

[0078] 18. The method according to any one of Embodiments 1 to 17, wherein the wax separated in step (d) contains at least 0.1% by weight, more preferably at least 5% by weight, and even more preferably at least 10% by weight of solvent, based on the total weight of the wax, and / or the separated wax contains up to 60% by weight, preferably up to 50% by weight, and more preferably up to 20% by weight of solvent.

[0079] 19. The method according to Embodiment 18, wherein the separated wax contains 0.1 to 50% by weight, more preferably 0.1 to 20% by weight, of the solvent based on the total weight of the wax.

[0080] 20. The method according to any one of Embodiments 1 to 19, wherein the pyrolysis residue is obtained by pyrolysis of plastics, particularly waste plastics.

[0081] 21. The method according to Embodiment 20, wherein the pyrolysis residue is obtained by pyrolyzing a plastic in a pyrolysis reactor and subsequently increasing the solid content concentration of the pyrolysis residue.

[0082] 22. The method according to Embodiment 20 or Embodiment 21, wherein the pyrolysis residue includes a liquid fraction, the proportion of which is preferably in the range of up to 95% by weight, more preferably 30 to 95% by weight, and particularly 50 to 88% by weight, based on the total weight of the pyrolysis residue.

[0083] 23. The method according to any one of Embodiments 20 to 22, wherein the pyrolysis residue is cooled before step (b) to a temperature preferably 260°C or lower, more preferably 220°C or lower, particularly preferably 180°C or lower, and / or preferably 80°C or higher, more preferably 100°C or higher, particularly preferably 120°C or higher.

[0084] 24. The method according to any one of Embodiments 1 to 23, wherein the separated wax is supplied to a processing plant of a refinery, particularly an FCC plant and / or a steam cracker, and preferably, when the wax is supplied to the processing plant, the temperature is 40°C or higher, preferably 50°C or higher, more preferably 80°C or higher, particularly 100°C or higher, or 40°C to 300°C, preferably 50°C to 280°C, even more preferably 80°C to 200°C, and even more preferably 100°C to 180°C.

[0085] 25. The method according to Embodiment 24, wherein the separated wax is mixed with a hydrocarbon stream before being supplied to a processing plant, particularly an FCC plant, the hydrocarbon stream having a boiling point (or lower end of the boiling point range) preferably 100°C or higher, more preferably 150°C or higher, and even more preferably 200°C or higher, and / or the mixture of wax and hydrocarbon stream preferably contains an amount of wax of 50% by weight or less, more preferably 20% by weight or less, even more preferably 10% by weight or less, particularly preferably 5% by weight or less, and especially 2% by weight or less, based on the total weight of the mixture.

[0086] 26. A device for obtaining wax from pyrolysis residue using a method according to any one of Embodiments 1 to 25, An introduction device for adding a solvent to the pyrolysis residue, A first separation device for separating at least a portion of a solid material from a high-solids mixture, A second separation device for separating at least a portion of the wax from a low-solids mixture, Equipped with, Preferably, a cooling unit (11) for cooling the pyrolysis residue is positioned upstream of the introduction device (14), preferably before the addition of the solvent.

[0087] 27. The device according to embodiment 26, wherein the introduction device comprises a metering device, in particular a metering pump.

[0088] 28. The device according to Embodiment 26 or Embodiment 27, wherein the first separation device comprises a weight separation device, a filter, a cyclone, a hydrocyclone, or a combination thereof, preferably a filter.

[0089] 29. The device according to any one of embodiments 26 to 28, wherein the second separation device comprises an evaporator and / or a device for extraction.

[0090] 30. A device for obtaining wax from plastic, particularly from waste plastic, comprising the device described in any of Embodiments 26 to 29 and a pyrolysis reactor for pyrolysis of the plastic to obtain a pyrolysis residue.

[0091] 31. The device according to Embodiment 30, further comprising a mixer, preferably an extruder, for plasticizing the plastic before adding it to a pyrolysis reactor.

[0092] 32. The device according to Embodiment 30 or Embodiment 31, further comprising a supply device for adding a diluent to the plastic, wherein the supply device is connected upstream of the pyrolysis reactor.

[0093] The present invention will be described in more detail below with reference to the illustrations of some embodiments, but is not limited thereto. [Brief explanation of the drawing]

[0094] [Figure 1] Figure 1 shows a flowchart of the pyrolysis method in which wax is obtained from the pyrolysis residue. [Modes for carrying out the invention]

[0095] As can be seen from Figure 1, a plastic containing at least 50% by weight of polyolefin is fed into the extruder 1, where it is plasticized and degassed. The plasticized plastic, having a temperature of at least 120°C, is then added to the static mixer 2. In the static mixer 2, a diluent 3 may be added to the plasticized plastic to reduce its viscosity. Instead of, or in addition to, the diluent 3, a portion of the liquid fraction 4 separated from the pyrolysis residue can be mixed with the plasticized plastic to reduce its viscosity. The resulting mixture is then fed into the pyrolysis reactor 5, where the plastic is pyrolyzed at a temperature of 350-450°C. As a result, a pyrolysis product 6 is obtained, which includes a gaseous fraction, a liquid fraction, wax, and solid materials. 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 within the hydrocyclone 7. Next, the separated portion of the gaseous fraction 8 can be further separated into light oil (for example, having a boiling point range of 35 to 225°C) and heavy oil (for example, having a boiling point range of 225 to 410°C) (not shown). Furthermore, the liquid fraction is at least partially separated within the hydrocyclone 7. The separated portion of the liquid fraction 4 is discharged through the outlet 9 of the hydrocyclone 7, as described above, and can be reused in a method for reducing the viscosity of plastics. At least a portion of the pyrolysis residue, at least partially containing wax and solid material, is discharged through the outlet 10 located at the bottom of the hydrocyclone 7.

[0096] As can be seen from Figure 1, the pyrolysis residue discharged through outlet 10 is supplied to cooling unit 11 to cool to a temperature in the range of 80-240°C. Subsequently, solvent 13 containing at least 20% by weight of aliphatic hydrocarbons is added to the pyrolysis residue in container 12 by introduction device 14 to obtain a high-solids mixture. The aliphatic hydrocarbons are selected from the group consisting of aliphatic hydrocarbons having 4-12 carbon atoms per molecule. The resulting high-solids mixture has a ratio of pyrolysis residue to solvent in the range of 1:1-1:3. Container 12 is heated so that dissolution can occur at a temperature in the range of 80-240°C. In a first separation device 15 equipped with a filter, the solid material is separated at least partially from the high-solids mixture to obtain a low-solids mixture. The separated solid material 16 is then dried in oven 17 at a temperature in the range of 100-200°C. Subsequently, individual components can be separated from the solid material and reused (not shown). The low-solids mixture is supplied to a second separation device 18 having an evaporator to separate the wax at least partially by evaporation. Evaporation occurs at a temperature in the range of 80 to 150°C and a pressure of 0.5 to 1 bar. The separated wax 19 can thus be used further. Subsequently, at least a portion of the solvent is separated from the low-solids mixture in the evaporator 20 and reused in step (b) of the method by being returned to the container 12 via the introduction device 14.

Claims

1. A method for obtaining wax from thermal decomposition residue, (a) A step of providing the pyrolysis residue, wherein the pyrolysis residue comprises the wax and a solid material, and the solid material comprises an inorganic salt, a ceramic raw material, asphaltene, tar, and / or coke, (b) A step of adding a solvent to the pyrolysis residue to obtain a high solids mixture containing the solid material and the solvent, wherein the wax is at least partially dissolved in the solvent. (c) A step of separating at least a portion of the solid material from the high solid content mixture in order to obtain a low solid content mixture, (d) A step of separating at least a portion of the wax from the low solids mixture. Methods that include...

2. The method according to claim 1, wherein the solvent comprises at least 20% by weight of an aliphatic hydrocarbon based on the total weight of the solvent.

3. The method according to claim 2, wherein the aliphatic hydrocarbon is selected from the group consisting of aliphatic hydrocarbons having a maximum of 15 carbon atoms per molecule, preferably 4 to 12 carbon atoms per molecule.

4. The method according to claim 3, wherein the aliphatic hydrocarbon is selected from n-pentane, n-hexane, n-heptane, isododecane, tetradecane, or a mixture thereof.

5. The method according to any one of claims 1 to 4, wherein in step (b), the dissolution of the wax in the solvent is carried out at a temperature of at least 80°C.

6. The method according to any one of claims 1 to 5, wherein the solid material is separated by sedimentation and subsequent filtration in step (c).

7. The method according to claim 6, wherein the filtration is performed at a temperature in the range of 100 to 250°C and a pressure of 5 bar or more.

8. The method according to any one of claims 1 to 7, wherein the solid material is dried after step (c).

9. The method according to any one of claims 1 to 8, wherein the separation of at least a portion of the wax in step (d) includes evaporation or extraction under pressure.

10. The method according to any one of claims 1 to 9, wherein the solvent contained in the low-solids mixture after step (d) is reused in step (b).

11. The method according to any one of claims 1 to 10, wherein the separated wax has a boiling point of at least 280°C.

12. The method according to any one of claims 1 to 11, wherein the wax separated in step (d) contains at least 0.1% by weight of the solvent.

13. The method according to any one of claims 1 to 12, wherein the thermal decomposition residue is obtained by thermal decomposing plastic, particularly waste plastic.

14. A device for obtaining wax from pyrolysis residue using the method according to any one of claims 1 to 13, An introduction device (14) for adding the solvent to the thermal decomposition residue, A first separation device (15) for separating at least a portion of the solid material from the high-solids mixture, A second separation device (18) for separating at least a portion of the wax from the low-solids mixture, Equipped with, A device in which a cooling unit (11) for cooling the pyrolysis residue is positioned upstream of the introduction device (14) before the addition of the solvent.

15. A device for obtaining wax from plastic, particularly from waste plastic, comprising the device described in claim 14 and a pyrolysis reactor (5) for pyrolysis of the plastic to obtain the pyrolysis residue.

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