Device for converting wax into oil

Abstract

Device for converting wax into oil in a pyrolysis process, characterized in that the device comprises - a pyrolysis reactor (2) comprising a bed material for pyrolyzing a feedstock (1), which includes plastic, to form a pyrolysis product (3), and a feeder for supplying the feedstock to the pyrolysis reactor, - at least one condensation device (8, 8a, 8b) to which the pyrolysis product is fed and in which the pyrolysis product is cooled, - a separation unit (10) comprising at least one separation device for separating at least one wax fraction (16) from the pyrolysis product, - a visbreaker unit (13) comprising at least one visbreaker furnace into which at least a part of the wax fraction (16) is fed and in which the wax fraction is cracked to form at least one oil product (11) comprising aliphatic compounds, and - at least one line for returning non-condensable gases (12) from the separation unit (10) to the pyrolysis reactor (2), the visbreaker unit (13) and / or a combustion chamber (6), and - the combustion chamber in which the bed material (7) of the pyrolysis reactor, which is separated from the pyrolysis product, is heated after the pyrolysis reactor (2).

Description

AREA

[0001] The application relates to a method according to claim 1 and a device according to claim 11 for converting wax into oil in a pyrolysis process. BACKGROUND

[0002] Pyrolysis products can be produced from various raw materials in a pyrolysis process. The raw materials can, for example, be pyrolyzed using catalytic pyrolysis.

[0003] To generate positive economic value and reduce environmental impact, discarded plastics such as polyethylene and propylene can be converted into chemicals and fuels. Pyrolysis has recently attracted the attention of both academia and industry as a promising, versatile approach to converting plastic waste into chemicals and fuels. However, implementing an efficient pyrolysis process with economically viable production remains a challenge. Furthermore, traditional plastic fuel technology, which relies on the consumption of fossil fuels, is not economically viable and does not contribute to a circular economy for plastics.However, a study of plastic fuel technology shows that converting plastic waste into naphtha or plastic monomers is a promising approach to producing new plastic in a closed loop.

[0004] The first generation of plastic pyrolysis was carried out in stirred tank reactors (STRs) and screw reactors. Extensive studies and, consequently, pilot plants using STRs and screw reactors were established to convert recycled waste plastics into oil. In these reactor types, the residence time of different plastic carbon chains is controlled, meaning that the smaller the compound formed, the faster it leaves the reactor (Scheirs, J., 2006, Overview of commercial pyrolysis processes for waste plastic, Feedstock Recycling and Pyrolysis of Waste Plastics, pp. 381-433).

[0005] Fluidized bed reactors could be a good option for scaling up the process. For example, companies like Anellotech (Anellotech, April 12, 2022, Plas-TCat™ for mixed plastic recycling, Anellotech, Inc.) or BioBTX (BioBTX, n.d., The BioBTX Technology) convert plastics into oil using catalytic pyrolysis. The end product from current catalytic pyrolysis converts the plastics into aromatics such as benzene, toluene, and xylene (BTX).

[0006] Traditional thermal pyrolysis in STR and screw reactors for the production of aliphatic monomers is subject to scalability limitations. Fluidized bed pyrolysis is a viable option for commercial-scale pyrolysis plants. However, a literature review and Valmet's experience have shown that fine-tuning the efficient process and defining the end product remain significant challenges. Depending on the temperature, notable formation of high-viscosity wax, high levels of non-condensable gas products, or traces of undesirable aromatics have been observed during thermal pyrolysis in various reactor technologies, particularly riser reactors.

[0007] The high content of wax or non-condensable gas compared to the required oil implies a low process yield and reduces the profitability of the plants. The wax or non-condensable gases produced cannot be easily transported to the refinery facilities. Furthermore, refineries are not interested in purchasing the wax produced.

[0008] One way to fine-tune the products from pyrolysis is the catalytic pyrolysis of PP / PE waste using a zeolite catalyst. This process yields a high content of aromatic compounds, including BTX, from plastic pyrolysis, but it only has a niche market. This is due to the fact that oil refinery companies are more interested in aliphatic hydrocarbons as feedstock for their hydrotreats and steam crackers. The aromatic compounds in the oil lead to high levels of coking, high hydrogen consumption, and catalyst poisoning during oil upgrading. Therefore, the conventional catalytic pyrolysis of plastics using zeolites is not an advantageous approach. TASK

[0009] The objective is to solve the problems mentioned above. Furthermore, the objective is to disclose a novel method and a novel apparatus for treating pyrolysis products after pyrolysis. The objective is also to upgrade unwanted pyrolysis products after pyrolysis. Finally, the objective is to convert wax formed in pyrolysis into an oil product comprising aliphatic compounds. SUMMARY

[0010] The method and apparatus are characterized by the features listed in the claims.

[0011] A process for converting wax into oil in a pyrolysis process, comprising feeding a feedstock comprising plastic to a pyrolysis reactor, pyrolyzing the feedstock to form a pyrolysis product, separating at least one wax fraction from the pyrolysis product in a separation unit and feeding the wax fraction to a visbreaker unit in which the wax fraction is treated to form at least one oil product, and / or to a pyrolysis plant comprising the pyrolysis reactor.

[0012] The device can include a pyrolysis reactor for pyrolyzing a feedstock comprising plastic to form a pyrolysis product, a feeder for supplying the feedstock to the pyrolysis reactor, a separation unit comprising at least one separation device for separating at least one wax fraction from the pyrolysis product, and a visbreaker unit into which at least the wax fraction is fed and in which the wax fraction is treated to form at least one oil product. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] The accompanying drawings, which are provided to further enhance understanding of the invention and form part of this description, illustrate some embodiments of the invention and, together with the description, help to explain the principles of the invention. The drawings include: Fig. 1 is a flowchart representation of a process according to one embodiment, Fig. Figure 2 is a flowchart representation of a process according to another embodiment, Fig. 3 is a flowchart representation of a process according to another embodiment and Fig. Figure 4 is a flowchart representation of a process according to another embodiment. DETAILED DESCRIPTION

[0014] In a process for converting wax to oil via pyrolysis, a feedstock comprising plastic is fed into a pyrolysis reactor and pyrolyzed to form a pyrolysis product. At least one wax fraction is separated from the pyrolysis product in a separation unit, and at least a portion of the wax fraction is fed to a visbreaker unit where it is cracked to form at least one oil product comprising aliphatic compounds. In one embodiment, the wax fraction or the entire wax fraction is fed to the visbreaker unit. The pyrolysis product can be fed to at least one condenser unit where it is cooled after leaving the pyrolysis reactor. Non-condensable gases can be recirculated from the separation unit to the pyrolysis reactor, the visbreaker unit, and / or a combustion chamber where a bed material of the pyrolysis reactor is treated.

[0015] An apparatus for converting wax into oil in a pyrolysis process comprises a pyrolysis reactor for pyrolyzing a feedstock comprising plastic to form a pyrolysis product, and a feeder for supplying the feedstock to the pyrolysis reactor. The apparatus further comprises a separation unit, comprising at least one separating device for separating at least one wax fraction from the pyrolysis product, and a visbreaker unit, comprising at least one visbreaker furnace into which at least a portion of the wax fraction is fed and in which the wax fraction is cracked to form at least one oil product comprising aliphatic compounds. The apparatus may further comprise at least one condensation device into which the pyrolysis product is fed and in which the pyrolysis product is cooled after the pyrolysis reactor.Furthermore, the device may include at least one line for returning non-condensable gases from the separation unit to the pyrolysis reactor, the visbreaker unit and / or a combustion chamber in which a bed material of the pyrolysis reactor is treated.

[0016] In another embodiment of the process for converting wax in a pyrolysis process, a feedstock comprising plastic is fed into a pyrolysis reactor and pyrolyzed to form a pyrolysis product. At least one wax fraction is separated from the pyrolysis product in a separation unit, and the wax fraction, or at least a portion thereof, is fed to a pyrolysis unit comprising the pyrolysis reactor, e.g., to a feedstock of the pyrolysis reactor or to the pyrolysis reactor itself. In one embodiment, the wax fraction is fed to the pyrolysis unit and the visbreaker unit, where the wax fraction is cracked to form at least one oil product comprising aliphatic compounds.

[0017] Some embodiments of the method and the device are described in Fig. 1, Fig. 2, Fig. 3 and Fig. 4 shown.

[0018] In this context, the feedstock comprising plastic means any feedstock or feedstock material that comprises at least plastic or plastic material. Furthermore, the feedstock may also comprise materials other than plastic. The feedstock may comprise one or more components. The plastic or plastic material may be recycled material, residue material, waste material, or virgin material, or combinations thereof, containing plastic, polymers, or mixtures thereof. In one embodiment, the feedstock is formed from recycled material, waste material, residue material, and combinations thereof. In another embodiment, the plastic may comprise any plastic or polymer, such as polyethylene, polypropylene, other polymers, or combinations thereof.

[0019] In this context, the pyrolysis product means any pyrolysis product formed by pyrolysis, for example, by catalytic pyrolysis. In one embodiment, the pyrolysis product is in a gaseous form. In another embodiment, the pyrolysis product is a product vapor.

[0020] In this context, the wax fraction means any fraction that includes at least wax. Furthermore, the wax fraction may contain tars and other impurities. In one embodiment, the wax fraction includes at least wax and tars. In another embodiment, the wax fraction includes wax, oil, and tars.

[0021] In this context, the term "oil product" means any product comprising at least aliphatic compounds. In one embodiment, the oil product is in vapor form, i.e., the oil product is an oil product vapor.

[0022] The feedstock, comprising plastic, is treated by pyrolysis in a pyrolysis reactor. Any suitable pyrolysis reactor can be used for the pyrolysis process. In one embodiment, the pyrolysis reactor is a fluidized bed reactor. The feedstock can be treated by thermal pyrolysis. In one embodiment, the pyrolysis is carried out at a low temperature of 500–800 °C, and in another embodiment at a temperature of 550–700 °C. In one embodiment, the residence time in the pyrolysis reactor can be 1–3 seconds.

[0023] The feedstock, which comprises plastic, can be fed into the pyrolysis reactor using the feeder. Any suitable feeder can be used for feeding. In one embodiment, the feeder is a screw feeder or an extruder.

[0024] The wax fraction is separated from the pyrolysis product in the separation unit. The separation unit comprises at least one separation device. In one embodiment, the separation unit comprises more than one separation device. In one embodiment, a separation unit or separation device capable of separating a desired fraction or product based on its boiling point is used to separate the wax fraction. In one embodiment, the separation unit comprises a distillation column, a scrubber, a condenser, a quench, or another suitable separation device. Alternatively, any suitable separation unit or separation device can be used to separate the wax fraction from the pyrolysis product. In one embodiment, the separation unit comprises at least one distillation column. In another embodiment, the separation unit comprises at least one scrubber and one distillation column.In one embodiment, the separation unit comprises at least one condensation device or condenser. After separation, the wax fraction can be fed to the visbreaker unit.

[0025] In one embodiment, the method comprises feeding the pyrolysis product to at least one condensation device or condenser in which the pyrolysis product is cooled. The pyrolysis product is cooled in the condensation device or condenser, and a condensed stream comprising wax and / or tars can be separated. In one embodiment, at least the wax fraction and optionally also gas and / or oil fractions are separated in the condensation device. In one embodiment, the device comprises at least one condensation device or condenser for cooling the pyrolysis product. In one embodiment, the device comprises at least one condensation device or condenser for cooling the pyrolysis product and for separating a condensed stream comprising wax and / or tars from the pyrolysis product.In one embodiment, the condensation device is arranged to separate at least the wax fraction and optionally also gas and / or oil fractions. Any suitable condensation device, condenser, or the like can be used for condensation. In one embodiment, the condensation device is used as the separation device of the separation unit.

[0026] In one embodiment, the method comprises feeding the pyrolysis product to at least one scrubber in which the pyrolysis product is cooled. In another embodiment, the method comprises feeding the pyrolysis product to at least one scrubber in which the pyrolysis product is cooled and a condensed stream comprising wax and / or tars is separated from the pyrolysis product, forming a non-condensed pyrolysis product. In one embodiment, at least the wax fraction and optionally also gas and / or oil fractions are separated in the scrubber or scrubbers. In one embodiment, the device comprises at least one scrubber for cooling the pyrolysis product. In another embodiment, the device comprises at least one scrubber for cooling the pyrolysis product and for separating a condensed stream comprising wax and / or tars from the pyrolysis product and forming a non-condensed pyrolysis product.In one embodiment, the scrubber(s) are arranged to separate at least the wax fraction and optionally also gas and / or oil fractions. In one embodiment, the scrubber is used as the separation device of the separation unit. In one embodiment, the device comprises at least two scrubbers or scrubber parts. In one embodiment, the device comprises more than two scrubbers, e.g., three, four, or more scrubbers. Any suitable scrubber, gas scrubbing device, or the like can be used as a scrubber. In one embodiment, the scrubbers are arranged in series. In one embodiment, the temperature of the pyrolysis product is 500–600 °C at the point of entry into the scrubber. In one embodiment, the temperature of the condensed material stream is 70–200 °C, and in another embodiment, 100–150 °C, after the scrubber(s).In one embodiment, the temperature of the fraction is 250 - 350 °C after the first scrubber.

[0027] In one embodiment, the separation unit is a distillation unit comprising at least one distillation column in which at least gas, oil, and wax fractions are separated. In another embodiment, the separation unit includes a distillation column for separating fractions from the pyrolysis product. In yet another embodiment, a distillation column is used as the separation device of the separation unit for separating fractions from the pyrolysis product. The distillation column can fractionate the pyrolysis product into different fractions depending on their boiling points. Furthermore, the distillation column can contain packing and trays. In one embodiment, the gas fraction is recovered from an upper part of the distillation column, one or more oil fractions are recovered from a middle part of the distillation column, and the wax fraction is recovered from a lower part of the distillation column.In one embodiment, the temperature of the wax fraction is 70–300 °C, and in another embodiment, 100–200 °C, after the distillation column. In one embodiment, the temperature of the gas fraction is 20–30 °C after the distillation column.

[0028] In one embodiment, a distillation column is used as the separation device of the separation unit to separate fractions from the pyrolysis product, and the process includes feeding the non-condensed pyrolysis product from the scrubber to the distillation column, in which at least gas, oil, and wax fractions are separated. In one embodiment, the device includes at least one line for feeding the non-condensed pyrolysis product from the scrubber to the distillation column, in which at least gas, oil, and wax fractions are separated. In one embodiment, the distillation column is used in the process with bottom and top boiling temperatures of approximately 100–150 °C and 20–30 °C, respectively; in another embodiment, approximately 100 °C and 25 °C, respectively.

[0029] In one embodiment, the wax fraction or a portion thereof is fed from the separation unit, such as the separation device (e.g., distillation unit or column, scrubber, or condenser), to the visbreaker unit. In another embodiment, the wax fraction or a portion thereof is fed to the pyrolysis unit, such as the pyrolysis reactor, or to a feedstock of the pyrolysis reactor.

[0030] In one embodiment, the wax fraction from the separation unit, e.g., distillation unit, and / or the condensed mass stream from the scrubber are fed to the visbreaker unit. In another embodiment, the device comprises at least one line for feeding the wax fraction from the separation unit, such as the distillation column, and / or the condensed mass stream from the scrubber to the visbreaker unit.

[0031] In one embodiment, the wax fraction is recovered from a bottom of the separation unit or separation device and fed to the visbreaker unit.

[0032] The wax fraction is treated in the visbreaker unit, preferably by cracking. In the visbreaker furnace of the visbreaker unit, the wax fraction is cracked into lighter products with shorter carbon chain lengths through indirect thermal contact with the furnace. In one embodiment, the visbreaker unit is based on a mild thermal cracking process. In one embodiment, the wax is cracked into lighter compounds at a temperature of 400–500 °C. In another embodiment, the wax is cracked into lighter compounds at a temperature of 400–500 °C with a residence time of 30 seconds to 30 minutes, preferably depending on the temperature, in a visbreaker furnace of the visbreaker unit. In one embodiment, the residence time is 1–10 minutes. In one embodiment, the residence time is less than 12 minutes, and in another embodiment, less than 10 minutes.Any suitable visbreaker furnace can be used for visbreaking. In one embodiment, the visbreaker unit can comprise a coil or soaker furnace. In one embodiment, the temperature of the oil product after the visbreaker furnace is 350–450 °C.

[0033] In one embodiment, the petroleum product is returned from the visbreaker unit to the separation unit, such as the separation device (e.g., distillation column, condenser, or scrubber), or to a feedstock of the separation device. In another embodiment, the petroleum product is returned from the visbreaker unit to the separation unit or the scrubber. In yet another embodiment, the petroleum product is returned from the visbreaker unit to the separation device of the separation unit or to the scrubber, which may be located upstream of the separation device of the separation unit. In yet another embodiment, the device comprises at least one line for returning the petroleum product from the visbreaker unit to the separation unit, such as to the separation device of the separation unit, or to the scrubber, which may be located upstream of the separation device of the separation unit.

[0034] In one embodiment, a bed material and / or pyrolysis carbon is separated from the pyrolysis product after the pyrolysis reactor. In one embodiment, the device comprises at least one cyclone or more than one cyclone for separating a bed material and / or pyrolysis carbon from the pyrolysis product after the pyrolysis reactor. In one embodiment, the device further comprises a combustion chamber into which at least the bed material, e.g., sand, is fed and in which the bed material of the pyrolysis reactor is heated. Any combustion chamber, e.g., a fluidized bed combustion chamber, can be used in the process. The heated bed material can be returned from the combustion chamber to the pyrolysis reactor.

[0035] In one embodiment, non-condensable gases are recirculated from the separation unit, e.g., from the separation device, to the pyrolysis reactor, the visbreaker unit, and / or a combustion chamber in which a bed material of the pyrolysis reactor is treated. In one embodiment, the device comprises at least one line for recirculating non-condensable gases from the separation unit to the pyrolysis reactor, the visbreaker unit, and / or a combustion chamber in which a bed material of the pyrolysis reactor is treated. Preferably, the visbreaker unit, the pyrolysis reactor, and the combustion chamber can obtain their energy from the non-condensable gases.

[0036] In one embodiment, at least a portion of the wax separated in the separation device, e.g., condenser or scrubber, is returned to the pyrolysis unit, such as to the feedstock of the pyrolysis reactor. In another embodiment, the device comprises at least one line for returning at least a portion of the wax separated in the separation device, e.g., condenser or scrubber, to the feedstock of the pyrolysis reactor. In another embodiment, a portion of the warm wax, preferably a small portion, is added to the feedstock to increase its temperature, thereby reducing the work required to heat the feedstock in the feedstock. Furthermore, the viscosity of the feedstock can be reduced.

[0037] In one embodiment, the wax fraction is heated upstream of the visbreaker unit by means of indirect contact with flue gas from the visbreaker unit and / or a combustion chamber in which a bed material of the pyrolysis reactor is treated. In another embodiment, the device comprises at least one heat exchanger for heating the wax fraction upstream of the visbreaker unit by means of indirect contact with flue gas from the visbreaker unit and / or a combustion chamber in which a bed material of the pyrolysis reactor is treated. In one embodiment, the temperature of the flue gas after the visbreaker unit is 600–800 °C. In another embodiment, the temperature of the flue gas after the heat exchange is 450–700 °C.

[0038] In one embodiment, the method and the device are based on a continuous process.

[0039] Thanks to this invention, wax and heavy tars formed during pyrolysis can be converted into oil with a high aliphatic compound content. This increases the plant's efficiency. Furthermore, energy can be saved by not cooling the wax to room temperature and transferring it to the visbreaker at a high temperature of approximately 100 °C. Flue gases from the visbreaker unit can be used to preheat the wax, thereby increasing the efficiency of both the visbreaker unit and the entire process. Additionally, a feedstock from the pyrolysis process can be heated using warm wax that is then returned to a feeder.

[0040] The method and apparatus offer a way to easily, energy-efficiently, and cost-effectively convert residue streams into desired products through pyrolysis. The present invention provides a technically applicable, simple, and affordable method for producing desired products from various raw materials. The method and apparatus are easy to implement in conjunction with manufacturing processes. EXAMPLES

[0041] Fig. 1, Fig. 2, Fig. 3 and Fig. Figure 4 shows some embodiments of the process for converting wax into oil in a pyrolysis process.

[0042] The device of Fig. 1- Fig. 4 comprises a pyrolysis reactor (2), such as a fluidized bed pyrolysis reactor, for pyrolyzing a feedstock (1) comprising plastic to form a pyrolysis product (3), and a feeder for supplying the feedstock to the pyrolysis reactor. The apparatus further comprises a separation unit (10), comprising at least one separation device for separating at least one wax fraction (16), and a visbreaker unit (13), comprising a visbreaker furnace. The wax fraction (16) is fed to the visbreaker unit (13), where the wax fraction is cracked to form at least one oil product (11) comprising aliphatic compounds. Air (15) can be supplied to the visbreaker furnace (13) via an air inlet.

[0043] The device of Fig. 1 comprises a scrubber (8) for cooling the pyrolysis product (3) and for separating a condensed stream (18) comprising wax and / or tars from the pyrolysis product and for forming a non-condensed pyrolysis product (9). The scrubber (8) of Fig. 2 comprises two washers, i.e., a first washer (8a) and a second washer (8b). The apparatus of Fig. 4 comprises more than two scrubbers, in this embodiment four scrubbers (8c, d, e, f), for cooling the pyrolysis product (3) and for separating the wax fraction (16), oil fractions (14a, 14b) and gas fraction (12).

[0044] In the device of Fig. 4. The scrubbers are used as the separating devices of the separation unit. In one embodiment of Fig. 4. The first washer (8c) can be optional and / or any number of washers can be used as the third and fourth washers (8e, f). In the apparatus of Fig. 4 The wax fraction (16) is fed via a line from the scrubber (8d) to the visbreaker unit (13).

[0045] In the device of Fig. 1 and Fig. 2 The separation device (10) of the separation unit is a distillation column in which a gas fraction (12), oil fractions (14a, 14b) and the wax fraction (16) are separated. The device includes a line for supplying the non-condensed pyrolysis product (9) from the scrubber (8, 8b) to the distillation column (10). Furthermore, the device includes lines for supplying the wax fraction (16) from the distillation column (10) and the condensed mass stream (18) from the scrubber (8). Fig. 1 or from the second washer (8b) of Fig. 2 to the visbreaker unit (13). The wax fraction (16) is recovered from a tray of the distillation column (10).

[0046] In the device of Fig. 3. The separation device (10) of the separation unit is a condensation device in which a gas fraction (12), oil fractions (14a, 14b), and the wax fraction (16) are separated. The device includes a line for feeding the wax fraction (16) or a portion thereof from the condensation device (10) to the visbreaker unit (13). The wax fraction (16) is recovered from a tray of the condensation device (10). Furthermore, the device may include a line for feeding the wax fraction or a portion thereof from the condensation device (10) to the feedstock of the pyrolysis reactor (2), and then the wax fraction or a portion thereof may be fed from the condensation device to the visbreaker unit and / or pyrolysis unit.

[0047] Furthermore, the device includes Fig. 2 and Fig. 4 a line for returning a portion of the wax (22) separated in the first scrubber (8a, 8c) to the feeder of the pyrolysis reactor. Furthermore, the device comprises Fig. 1- Fig. 4 lines for returning non-condensable gases of the gas fraction (12) from the separation device (10), such as the distillation column or condensation device, or from the scrubber (8f) to the pyrolysis reactor (2), the visbreaker unit (13) and / or a combustion chamber (6) in which a bed material of the pyrolysis reactor is treated. The device of Fig. 1, Fig. 2 and Fig. 4 further comprises a line for returning the oil product (11) from the visbreaker unit (13) to the scrubber (8), and the device of Fig. 3 includes a line for returning the oil product (11) from the visbreaker unit (13) to a feedstock of the condensation device.

[0048] Furthermore, the apparatus of the figures includes a cyclone (4) for separating bed material and / or pyrolysis carbon from the pyrolysis product (3) after the pyrolysis reactor (2). The apparatus also includes a combustion chamber (6) in which the bed material (5), such as sand, is heated. The heated bed material (7) is returned from the combustion chamber to the pyrolysis reactor (2). Air (19) can be supplied to the combustion chamber via an air inlet.

[0049] Furthermore, the apparatus of the figures includes a heat exchanger (20) for heating the wax fraction (16) upstream of the visbreaker unit (13) using indirect contact with flue gas (17) from the visbreaker unit (13). Alternatively, exhaust gas (21) from the combustion chamber (6) is used to heat the wax fraction in the heat exchanger. Example 1

[0050] In this process, wax is processed in a pyrolysis process according to the Fig. 1 and Fig. 2 converted into oil.

[0051] A plastic feedstock (1), comprising PP / PE waste and with a chain length (C) of 4000–40000, is atomized and fed into a fluidized bed riser pyrolysis reactor (2). The feedstock is pyrolyzed at a temperature of approximately 500–600 °C and a residence time of 1–3 s to form a pyrolysis product vapor (3). Sand and / or pyrolysis carbon are separated from the pyrolysis product in a cyclone (4) downstream of the pyrolysis reactor. The sand is treated in a combustion chamber containing a fluidized bed, causing the pyrolysis carbon to combust and heat the sand. The hot sand is returned to the pyrolysis reactor. Air (19) can be supplied to the combustion chamber (6).

[0052] From the cyclone (4), the pyrolysis product vapor (3) is fed at a temperature of approximately 500 °C to a scrubber (8), where the pyrolysis product vapor is cooled and a condensed stream (18), comprising wax and / or tars, is separated from the pyrolysis product, forming a non-condensed pyrolysis product (9). The temperature of the condensed stream (18) can be approximately 100 °C downstream of the scrubber. In the process according to Fig. 2. The temperature of the fraction can be approximately 300 °C after the first scrubber (8a) and approximately 100 °C after the second scrubber (8b). The non-condensed pyrolysis product (9) is fed from the scrubber (8) or the last scrubber (8b) to the distillation column (10), in which gas (12), oil (14a, 14b), and wax (16) fractions are separated. The temperature of the wax fraction (16) is approximately 250 °C after the distillation column.

[0053] The wax fraction (16) is fed from a tray of the distillation column to a visbreaker furnace (13), where it is cracked to form an oil product containing aliphatic compounds. The wax fraction (16) comprises at least wax and tars, with a chain length C of less than 100–200. The condensed stock stream (18) from the scrubber can be combined with the wax fraction stream (16), and the combined stream can be fed to the visbreaker furnace. The wax fraction or the combined stream can be heated in a heat exchanger (20) upstream of the visbreaker furnace by means of indirect contact with flue gas (17) from the visbreaker furnace (13) and / or exhaust gas from the combustion chamber (6). The temperature of the flue gas (17) can be approximately 700 °C downstream of the visbreaker furnace and approximately 500 °C downstream of the heat exchanger. In the visbreaker furnace, the wax fraction is cracked to form the oil product (11).The wax can be cracked into lighter compounds at a temperature of 400–500 °C with a residence time of 1–10 minutes in the visbreaker oven. Air (15) can be supplied to the visbreaker (13). The temperature of the oil product can be approximately 400 °C after visbreaking. The oil product (11) can be returned from the visbreaker oven to the scrubber.

[0054] The non-condensable gases (12), such as light gases, from the distillation column (10) can be returned to the pyrolysis reactor (2), the visbreaker furnace (13), and / or the combustion chamber (6). The temperature of the non-condensable gases can be approximately 25 °C downstream of the distillation column.

[0055] In the process according to Fig. 2. A portion of the wax separated in the first scrubber (8a) can be recycled to the feedstock of the pyrolysis reactor (2). This warm wax can then be used to heat the plastic feedstock (1), e.g., at the beginning of the extruder.

[0056] The pyrolysis reactors, combustion chambers, scrubbers, distillation columns and visbreaker furnaces and other process devices and equipment located in the Fig. 1- Fig. The 4 elements used are known in engineering and are therefore not described in more detail in this context.

[0057] The method and the apparatus are suitable in different embodiments for the production of desired products from different raw materials and for the conversion of wax fractions of the products.

[0058] The invention is not limited to the examples mentioned above; instead, many variations are possible within the scope of the inventive concept defined by the claims. QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited non-patent literature

[0000] Scheirs, J., 2006, Overview of commercial pyrolysis processes for waste plastic, Feedstock Recycling and Pyrolysis of Waste Plastics, pp. 381-433

[0004] Anellotech, April 12, 2022, Plas-TCat™ for mixed plastic recycling, Anellotech, Inc.

[0005]

Claims

[1] Device for converting wax into oil in a pyrolysis process, characterized by that the device includes - a pyrolysis reactor (2) comprising a bed material for pyrolyzing a feedstock (1), which includes plastic, to form a pyrolysis product (3), and a feeder for supplying the feedstock to the pyrolysis reactor, - at least one condensation device (8, 8a, 8b) to which the pyrolysis product is fed and in which the pyrolysis product is cooled, - a separation unit (10) comprising at least one separation device for separating at least one wax fraction (16) from the pyrolysis product, - a visbreaker unit (13) comprising at least one visbreaker furnace into which at least a part of the wax fraction (16) is fed and in which the wax fraction is cracked to form at least one oil product (11) comprising aliphatic compounds, and - at least one line for returning non-condensable gases (12) from the separation unit (10) to the pyrolysis reactor (2), the visbreaker unit (13) and / or a combustion chamber (6), and - the combustion chamber in which the bed material (7) of the pyrolysis reactor, which is separated from the pyrolysis product, is heated after the pyrolysis reactor (2). [2] Device according to claim 1, characterized by , that the separation unit (10) is a distillation unit comprising at least one distillation column in which at least gas, oil and wax fractions are separated. [3] Device according to claim 1 or 2, characterized by , that the device comprises at least one scrubber (8) for cooling the pyrolysis product (3) and for separating a condensed material stream (18) comprising wax and / or tars from the pyrolysis product and for forming a non-condensed pyrolysis product (9). [4] Device according to claim 3, characterized by, that the device comprises at least one line for supplying the non-condensed pyrolysis product (9) from the scrubber (8) to the distillation column in which at least gas, oil and wax fractions are separated. [5] Device according to any one of claims 1 to 4, characterized by , that the device comprises at least one line for supplying the wax fraction (16) from the separation device of the separation unit (10) and / or the condensed material stream (18) from the scrubber to the visbreaker unit (13). [6] Device according to any one of claims 1 to 5, characterized by , that the device includes at least one conduit for returning at least a portion of the wax separated in the separation device to the feeder of the pyrolysis reactor (2). [7] Device according to any one of claims 1 to 6, characterized by, that the device comprises at least one cyclone (4) for separating a bed material and / or pyrolysis charcoal (5) from the pyrolysis product (3) downstream of the pyrolysis reactor (2). [8] Device according to any one of claims 1 to 7, characterized by that the device includes at least one line for returning the oil product (11) from the visbreaker unit (13) to the separation unit (10) or the scrubber (8). [9] Device according to any one of claims 1 to 8, characterized by , that the device comprises at least one heat exchanger (20) for heating the wax fraction (16) upstream of the visbreaker unit (13) using indirect contact with flue gas from the visbreaker unit (13) and / or a combustion chamber (6) in which the bed material of the pyrolysis reactor is treated. [10] Device according to any one of claims 1 to 9, characterized by, that the visbreaker furnace of the visbreaker unit (13) is arranged such that it cracks the wax into lighter compounds at a temperature of 400 - 500 °C and with a residence time of 30 s - 30 min.

Images