Staggered heat exchanger for cracking hydrocarbons

Abstract

A device for heating and melting long-chain hydrocarbons comprises a first heating section, and the first heating section is provided with at least one first material flow pipe extending from an inlet of the first heating section to an outlet of the first heating section. The first material flow pipe provides a flow path from the first heating section inlet to the first heating section outlet for the molten long-chain hydrocarbon, and a first heating structure extending along at least a part of the first material flow pipe, and the first heating structure is configured to transfer heat to the first material flow pipe; the second heating section is provided with at least one second material flow pipe and at least one third material flow pipe, the at least one second material flow pipe extends from the second heating section inlet to the second heating section outlet, and the at least one third material flow pipe extends from the third heating section inlet to the third heating section outlet; the second material flow pipe and the third material flow pipe respectively provide flowing paths from the second heating section inlet and the third heating section inlet to the second heating section outlet and the third heating section outlet for the molten long-chain hydrocarbon; wherein the second heating section inlet and the third heating section inlet are configured to receive the molten long-chain hydrocarbon from the first heating section outlet and divert the flow path of the molten long-chain hydrocarbon to the at least one second material flow pipe and the at least one third material flow pipe; and wherein the second heating section inlet and the third heating section inlet are arranged at different heights.

Description

Technical Field

[0001] The present invention generally relates to methods and equipment for processing waste plastics by pyrolysis, and the products obtained therefrom. More specifically, the present invention relates to methods and equipment for heating plastics to pyrolysis temperature. In addition, the present invention relates to a system for separating gases, liquids, and optionally solid particles in pyrolyzed materials. The present invention further relates to a method and system for cracking long-chain hydrocarbons and separating the resulting products, particularly to methods and systems for processing plastics and polyolefins by pyrolysis. Background Art

[0002] Today's society generates a large amount of waste plastics. Although the recycling of plastics is becoming more and more efficient and effective, there are still many cases where waste plastics cannot be effectively or efficiently recycled. They are discarded in landfills, where they take many years to degrade, or may leak into the environment, causing damage to the ecosystem.

[0003] However, plastic materials are essentially made of useful compounds that can be used directly and / or converted for (re)use. For example, fuels such as diesel can be extracted from waste plastics, or waste plastics can be converted into raw materials suitable for synthesizing new materials (such as new plastics, other hydrocarbon materials, or similar materials). The materials recovered from waste plastics may help to at least partially replace the hydrocarbons traditionally obtained from natural gas or mineral oil.

[0004] The output of a plastic chemical plant usually includes light hydrocarbons (LHC), heavy hydrocarbons (HHC), carbon, and non-condensable (gases). Currently, LHC, HHC, or their mixtures are the most desirable products, but this depends on the market.

[0005] The industry requires that the LHC and HHC fractions meet certain chemical and physical specifications, such as vapor pressure, initial boiling point, final boiling point, flash point, viscosity, cloud point, and cold filter plugging point. Different customers or end uses may require different qualities, but it is very important for a plastic chemical plant to produce products with stable quality. The final quality of the product fractions is controlled by distillation columns well-known and commonly used in the petrochemical industry. It is desirable for the fractions to be relatively pure, such that the light and heavy hydrocarbons do not contain a large amount of high-boiling compounds. Such high-boiling compounds increase the cold filter plugging point and cloud point, which are generally unacceptable to purchasers of pyrolysis oil.

[0006] In a plastic chemical plant, raw plastics (which may mainly consist of polyethylene and polypropylene from domestic sources) are used as input. These plastics, which are composed of long-chain hydrocarbons, are then cracked into shorter chains, thereby forming a variety of molecules with various chain lengths. As is well known, these mixtures can be distilled into various temperature-determined fractions.

[0007] Methods known in the art for converting waste plastics into diesel and the like are thermochemical decomposition processes, i.e., pyrolysis. Pyrolysis is the thermal decomposition of waste plastics in an inert atmosphere. In fact, the long polymer chains of plastic polymers are cracked by heating, producing shorter hydrocarbon chains, which are generally more useful as products.

[0008] Pyrolysis is a preferred method for the thermochemical decomposition of waste plastic materials. Various attempts have been made previously to provide pyrolysis of waste plastics that is technically and cost-effective.

[0009] The techniques discussed in patent publications US2018 / 0010050 and WO2021053139 have achieved technically useful results, the contents of which are incorporated herein by reference.

[0010] US2018 / 0010050A1 discusses a method for recovering hydrocarbons from plastic waste (especially polyolefin-rich waste) by pyrolysis without using a catalyst. The process includes melting the plastic waste in two heating devices and mixing the stream from the cracking reactor with the molten plastic waste introduced into the first heating device. The heated molten plastic is transferred to a cracking reactor where the plastic material is cracked. Subsequently, the cracked material is distilled into diesel and low-boiling substances.

[0011] WO2021 / 053139A1 provides many improvements over US2018 / 0010050A1. Among other things, it discusses a method for decomposing long-chain hydrocarbons from plastic-containing waste, which includes providing a material containing long-chain hydrocarbons; heating a specific volume of the material containing long-chain hydrocarbons to a cracking temperature at which the hydrocarbon chains in the material begin to crack into shorter chains; and for a specific volume at a temperature higher than the cracking temperature, exposing the specific volume to heat that is lower than or equal to 50 °C above the temperature of the specific volume. After the specific volume of the material is exposed to heat, WO2021 / 053139 transfers the partially cracked molten plastic stream to a gas-liquid separation structure. The separation structure, also called a reactor, includes a separation zone containing a gas-liquid boundary, and a settling zone for the accumulation of heavy hydrocarbons and / or solid carbon and possibly other solids (such as aluminum, sand, dirt, etc.).

[0012] Although good results have been achieved based on the above techniques, there is still room for further improvement. For example, it would be useful to provide a system and process that is more versatile than the previously attempted systems.

[0013] EP 2 876 146 B1 discusses a tested technique, in which the method for recovering hydrocarbons from polyolefin plastic recyclables by pyrolysis cracking includes: introducing the plastic recyclables into a mixing container under an inert gas and mixing with diesel, removing water vapor in a first heating zone, removing acidic gases in a second heating zone, liquefying the unmolten plastic recyclables in a third heating zone, cracking the plastic recyclables in a cracking reactor at about 400 degrees Celsius, performing partial condensation to prevent the discharge of paraffin, and fractionating the cracking products.

[0014] In one aspect, an object of the present invention is to provide an alternative, and preferably to provide improvements in pyrolysis processes and equipment. For example, an object of the present invention is to provide improvements in heating long-chain hydrocarbons.

[0015] Previous attempts have been made to achieve effective pyrolysis of waste plastics.

[0016] An example is discussed in patent publication WO11077419 A1, which relates to a process for treating waste plastics, in which the plastics are melted and then pyrolyzed in an oxygen-free atmosphere in a jacket-heated pyrolysis container to provide pyrolysis gas. The pyrolysis gas flows upward through a pipe directly connecting the pyrolysis chamber and the contactor container, contacts the plates in the contactor container, such that some long-chain gas components condense. The condensate flows downward through the same pipe and returns directly to the pyrolysis zone. The condensate is then reheated in the pyrolysis zone and further pyrolyzed. The short-chain gas components leave the contactor in gaseous form and continue to distill.

[0017] WO11077419 A1 explains that when a batch is finished, an increase in the load on the pyrolysis chamber agitator indicates that carbon drying is taking place and that the process is about to end. The pyrolysis chamber is then cleaned by operating the double-helix agitator blades in reverse to remove the carbon, and nitrogen is passed upward through the contactor and out directly to a thermal oxidizer to flush any residual hydrocarbons. At this stage, the pyrolysis container and the contactor are isolated from the rest of the system. Such a process and system may have problems and be suboptimal. For example, adding an agitator to the pyrolysis chamber and directly heating the pyrolysis chamber by a jacket is complex but necessary. The system also utilizes a specific type of jacket-cooled contactor with inclined and perforated cooling contactor baffles to enable the condensed hydrocarbons to return directly from the contactor to the pyrolysis chamber through the same pipe through which the pyrolysis gas enters the contactor. This can be complex; the pyrolysis process results in the batch completion of a dry carbon (carbon) product; and the cleaning associated with an extended downtime of the pyrolysis reactor.

[0018] In previous attempts, a partial condenser was directly arranged on top of the pyrolysis vessel to return heavy hydrocarbons for further cracking. It has been found that the generality, robustness, and efficiency of some of these attempts are not optimal. Without being bound by theory, through technical investigation, it has been identified that the condensate directly returned from the partial condenser to the pyrolysis reaction vessel may cause inconsistent temperatures and heat losses in the pyrolysis zone, requiring complex heat input in the pyrolysis zone and potentially resulting in hot spots, carbonization, complex agitation, and / or energy losses. It may be desirable to provide a process and system that are less affected by such drawbacks.

[0019] Another example is discussed in CH708681A1, which relates to a method for recovering hydrocarbons from polyolefin plastic recyclables by pyrolytic cracking. The plastic recyclables are introduced into a mixing vessel under an inert gas and mixed with diesel. Water vapor is removed in a first heating zone, acidic gases are removed in a second heating zone, the unmelted plastic recyclables are liquefied in a third heating zone, the plastic recyclables are cracked in a cracking reactor at about 400 °C, partial condensation is carried out to prevent the discharge of paraffin, and the cracked products are fractionated.

[0020] The partial condenser in CH708681A1 is separate from and at a certain distance from the pyrolysis reactor, and there is a connecting pipe to guide the pyrolysis gas from the pyrolysis reactor to the partial condenser. The partial condenser is adjusted so that heavy hydrocarbons that do not have the desired product characteristics are condensed and sent back to the third heating zone through a separate pipe, where the heavy hydrocarbons are further cracked. The additional cracking loop reduces the content of overly heavy hydrocarbons in the product.

[0021] Attempts to implement concepts related to those disclosed in CH708681A1 have found that while products can be produced, they exhibit some instability and inefficiency in pyrolysis, such as the need for complex heating in the pyrolysis zone. In addition, due to the pressure difference between the partial condenser and the heating zone where the heavy hydrocarbons are returned, the system of CH708681A1 may be complex to implement.

[0022] Other attempts include US10160920 BB, which uses a sequential cracking process to thermally crack hydrocarbon feedstocks in a cascade cracking device; US2007227874 AA discusses a method for recovering fractionated hydrocarbons from recycled plastics; and US5580443 A discusses a process for thermally cracking low-quality feedstocks containing a relatively large proportion of heavy fractions (such as high-boiling fractions).

[0023] All references, including any patents or patent applications, cited in this specification are hereby incorporated by reference. It is not admitted that any reference constitutes prior art. Summary of the Invention

[0024] Although the present invention is defined in the independent claims, other aspects of the invention are set forth in the dependent claims, the drawings, and the following description. Description of the Drawings

[0025] The drawings are not drawn to scale. Like numbers refer to like components.

[0026] Figure 1 An assembly for cracking long-chain hydrocarbons is shown;

[0027] Figure 2 An embodiment of the heating structure is shown in more detail;

[0028] Figure 3 Another embodiment of the heating structure is shown;

[0029] Figure 4 Another embodiment of the heating structure is shown; and

[0030] Figure 5 Another embodiment of the heating structure is shown. Detailed Description

[0031] Figure 1 An assembly for cracking long-chain hydrocarbons according to an embodiment of the present invention is shown. Before further describing the details of the illustrated embodiment, the general aspects of the present invention are set forth below.

[0032] According to one aspect, an apparatus for heating molten long-chain hydrocarbons includes: a heating section having at least one material flow tube extending from a heating section inlet to a heating section outlet, the material flow tube providing a flow path for the molten long-chain hydrocarbons from the heating section inlet to the heating section outlet, and a heating structure extending along at least a portion of the material flow tube, the heating structure being configured to transfer heat to the material flow tube; and a disengaging volume located downstream of the material flow tube, the disengaging volume being configured to disengage hydrocarbon bubbles in the gas phase from the hydrocarbon in the liquid phase and rise such that the hydrocarbon in the liquid phase occupies the lower portion of the disengaging volume while the hydrocarbon in the gas phase occupies the higher portion of the disengaging volume, wherein the apparatus is configured to keep the hydrocarbon in the gas phase separated from the hydrocarbon in the liquid phase.

[0033] In various embodiments, the heating section is a first heating section, at least one material flow tube is a first material flow tube, the heating section inlet is a first heating section inlet, the heating section outlet is a first heating section outlet, and the heating structure is a first heating structure; and the apparatus further includes a second heating section having at least one second material flow tube and at least one third material flow tube, at least one second material flow tube extending from a second heating section inlet to a second heating section outlet, at least one third material flow tube extending from a third heating section inlet to a third heating section outlet, the second and third material flow tubes respectively providing a flow path for the molten long-chain hydrocarbon from the second and third heating section inlets to the second and third heating section outlets, wherein the second heating section inlet and the third heating section inlet are configured to receive the molten long-chain hydrocarbon from the disengaging volume and split the flow path of the molten long-chain hydrocarbon to at least one second material flow tube and at least one third material flow tube; and wherein the second heating section inlet and the third heating section inlet are arranged at different heights.

[0034] According to one aspect, an apparatus for heating a molten long-chain hydrocarbon includes a first heating section having at least one first material flow tube extending from a first heating section inlet to a first heating section outlet, the first material flow tube providing a flow path for the molten long-chain hydrocarbon from the first heating section inlet to the first heating section outlet, and a first heating structure extending along at least a portion of the first material flow tube, the first heating structure being configured to transfer heat to the first material flow tube; and a second heating section having at least one second material flow tube and at least one third material flow tube, at least one second material flow tube extending from a second heating section inlet to a second heating section outlet, at least one third material flow tube extending from a third heating section inlet to a third heating section outlet, the second and third material flow tubes respectively providing a flow path for the molten long-chain hydrocarbon from the second and third heating section inlets to the second and third heating section outlets, wherein the second heating section inlet and the third heating section inlet are configured to receive the molten long-chain hydrocarbon from the first heating section outlet and split the flow path of the molten long-chain hydrocarbon to at least one second material flow tube and at least one third material flow tube; and wherein the second heating section inlet and the third heating section inlet are arranged at different heights.

[0035] When molten long-chain hydrocarbons are received and heated above the temperature at which some of the hydrocarbons begin to crack, water, HCI, and other contaminants contained in the material containing the long-chain hydrocarbons, as well as some of the hydrocarbons, will become gaseous. For convective heating, the volume in the gas phase impedes heat transfer to the long-chain hydrocarbons because the gas phase has poor thermal conductivity, thus impeding the heating of the long-chain hydrocarbons in the liquid phase. If the long-chain hydrocarbons are heated in a continuous process where the molten hydrocarbons enter a tubular heating zone at an inlet and the hydrocarbons at an elevated temperature leave the heating zone at an outlet, the volume of hydrocarbons in the gas phase will increase. Due to the low thermal conductivity of the gas phase, this may impede the heating of further hydrocarbons passing through the heating zone. The increasing volume of hydrocarbons in the gas phase further drives the liquid phase through the heating zone, causing the liquid phase to pass through the heating zone faster and potentially experience less heating.

[0036] The inventors have recognized that the mass density of hydrocarbons in the gas phase and the liquid phase can be used to separate the liquid phase and the gas phase in a manner that overcomes at least some of the above challenges, without necessarily requiring the removal of the gas phase from the continuous process. While such removal would eliminate the complexity of the hydrocarbons in the continuous process, it would increase the complexity of the flow paths required for the continuous process.

[0037] In one embodiment, the present invention thus provides a plurality of heat exchangers configured for continuous operation, the plurality of heat exchangers being arranged in series such that molten long-chain hydrocarbons continuously pass through the plurality of heat exchangers. At least a second heat exchanger includes at least two material flow tubes arranged in parallel vertically, such that the long-chain hydrocarbons in the gas phase preferentially pass through at least one of the upper material flow tubes, while the long-chain hydrocarbons in the liquid phase preferentially pass through at least one of the lower material flow tubes.

[0038] The directions and orientations such as up, down, top, bottom, higher, upper, lower, horizontal, and vertical are provided below with reference to the direction of local gravity.

[0039] In various embodiments, the flow paths of the molten long-chain hydrocarbons in the second material flow tube and the third material flow tube merge near the outlet of the second heating section and the outlet of the third heating section. That is, portions of the flow paths can bypass other portions of the parallel flow paths.

[0040] In various embodiments, the first heating section has at least two material flow tubes that separate the flow path of the molten long-chain hydrocarbons adjacent to the inlet of the first heating section and merge the flow path of the molten long-chain hydrocarbons adjacent to the outlet of the first heating section. Since the molten long-chain hydrocarbons may contain gas bubbles even when entering the first heating section, the arrangement of the first heating section is such that portions of the flow path specifically containing gas bubbles can bypass other portions of the parallel flow paths. In addition, having more than one material flow tube increases the surface area for heating the molten long-chain hydrocarbons.

[0041] In various embodiments, the second heating section has at least two second material flow tubes and / or at least two third material flow tubes. Having more than one second material flow tube and third material flow tube increases the surface area for heating the molten long-chain hydrocarbon.

[0042] In various embodiments, the top of the first heating section is at the same level as the bottom of the second heating section. This allows gas to flow downstream, while liquid can be discharged in the opposite direction if desired.

[0043] In various embodiments, the first heating section and / or the second heating section are configured to crack and separate the molten long-chain hydrocarbon into hydrocarbons in the gas phase and long-chain hydrocarbons in the liquid phase. Thus, the heating section has a structure for regulating pressure, temperature, and / or mass flow to allow hydrocarbon cracking.

[0044] In various embodiments, the device further includes a connection portion between the first heating section and the second heating section, where the connection portion forms a flow path for the molten long-chain hydrocarbon from the first heating section to the second heating section, and the device is configured to maintain the separation of hydrocarbons in the gas phase and long-chain hydrocarbons in the liquid phase when passing through the connection portion. The connection portion is preferably a connecting pipe having a circular inner cross-section. To maintain separation, the connecting pipe has a minimum inner diameter that is a function of the assumed mass flow rate, temperature, pressure, and / or gas content. In various embodiments, the inner cross-section of the connecting pipe is adapted to allow solid materials to pass through and avoid blockage. In some embodiments, such solid materials are metals, sand, and / or glass present in the received material containing long-chain hydrocarbons. The melting point of the solid material is higher than that of the long-chain hydrocarbon, so it remains in the solid phase during processing. By accommodating such solid materials, the range of materials that can be acceptably processed becomes wider and / or easier to prepare for processing.

[0045] In various embodiments, the connection portion is configured such that the flow path extends substantially horizontally or at an angle of 0° to 45° with respect to the horizontal plane, preferably at an angle of 0° to 35° with respect to the horizontal plane, preferably at an angle of 0° to 25° with respect to the horizontal plane, preferably at an angle of 0° to 15° with respect to the horizontal plane, preferably at an angle of 0° to 10° with respect to the horizontal plane, and the downstream end of the flow path is higher than the upstream end. This further supports the flow of gas in the downstream direction, while liquid can be discharged in the opposite direction if desired.

[0046] In various embodiments, the connection portion and / or the mass flow rate are adjusted to maintain the separation of hydrocarbons in the gas phase and long-chain hydrocarbons in the liquid phase, and the flow pattern of hydrocarbons in the gas phase and long-chain hydrocarbons in the liquid phase inside the connection portion is preferably one of bubble, slug, stratified, wavy, or slug flow patterns. In these flow patterns, the separated hydrocarbons in the gas phase can better bypass the long-chain hydrocarbons in the liquid phase when splitting in the upper and lower material flow tubes.

[0047] In various embodiments, the connection portion provides a single fluid passage having a circular cross-section.

[0048] In various embodiments, the device is configured to provide at the connection portion a temperature between 250 °C and 450 °C, preferably between 250 °C and 350 °C and / or between 350 °C and 450 °C, a mass flow rate of 500 kg / h to 30,000 kg / h, preferably 1000 kg / h to 20,000 kg / h, preferably 5000 kg / h to 15,000 kg / h, preferably 8000 kg / h to 12,000 kg / h, a gas content of hydrocarbons in the gas phase of 1 mass % to 50 mass %, preferably 5 mass % to 40 mass %, preferably 10 mass % to 30 mass %, preferably 15 mass % to 20 mass %, a pressure between 50 kPa and 10,000 kPa relative to ambient air pressure, preferably between 100 kPa and 8100 kPa, preferably between 300 kPa and 6000 kPa, preferably between 500 kPa and 4000 kPa, preferably between 700 kPa and 2000 kPa, and a connection portion having a circular cross-section with an inner diameter of at least 20 mm, preferably at least 35 mm, preferably at least 50 mm, preferably at least 100 mm.

[0049] In the context of the present disclosure, the pressure is gauge pressure and is thus referenced to zero ambient air pressure.

[0050] In more specific embodiments, the device is configured to provide at the connection portion a temperature between 250 °C and 450 °C, a mass flow rate of 1000 kg / h to 20,000 kg / h, a gas content of hydrocarbons in the gas phase of 1 mass % to 50 mass %, preferably a pressure between 100 kPa and 8100 kPa, and a connection portion having a circular cross-section with an inner diameter of at least 50 mm. Within these ranges, the flow pattern of hydrocarbons in the gas phase and long-chain hydrocarbons in the liquid phase within the connection portion is expected to be one of bubble, slug, stratified, wavy or plug flow patterns.

[0051] In various embodiments, for solid materials suspended in molten long-chain hydrocarbons, the connection portion and / or at least one of the first material flow tube, the second material flow tube or the third material flow tube provides an inner cross-section adapted to allow solid materials of a predetermined maximum size to pass through. Thus, if the longest dimension of the solid material does not exceed the predetermined size, e.g., between 1 and 20 mm, preferably between 1 and 10 mm, the corresponding inner cross-section determines the possible presence of solid materials in the long-chain hydrocarbons. In various embodiments, at least one of the first material flow tube, the second material flow tube or the third material flow tube provides a circular inner cross-section with a diameter in the range of 1 to 50 mm, preferably between 20 and 30 mm.

[0052] In various embodiments, the connecting portion is provided with an upper connecting pipe and a lower connecting pipe; the upper connecting pipe is arranged to allow hydrocarbons in the gas phase to pass through, and the lower connecting pipe is arranged to allow long-chain hydrocarbons in the liquid phase to pass through, wherein the lower connecting pipe preferably provides an inner cross-section suitable for allowing solid materials of a predetermined maximum size to pass through. By using the upper connecting pipe and the lower connecting pipe, the separation of the gas phase and the liquid phase can be maintained within a wider range than the range provided above.

[0053] In various embodiments, the lower connecting pipe is further arranged to allow solid materials such as metals, glass and / or sand to pass through up to a predetermined maximum size. As more and more long-chain hydrocarbons in the liquid phase are converted into the gas phase, the proportion of solid materials in the lower connecting pipe increases as the long-chain hydrocarbons pass through each heating section.

[0054] In various embodiments, the device includes at least one third heating section, each of the at least one third heating section having at least two fourth material flow pipes, each fourth material flow pipe extending from a respective fourth heating section inlet to a respective fourth heating section outlet, wherein the flow path diverges between at least two fourth material flow pipes adjacent to the fourth heating section inlet and converges adjacent to the fourth heating section outlet, and each of the first heating section, the second heating section, and the at least one third heating section is configured such that a material containing long-chain hydrocarbons continuously flows through each of them. Each heating section further increases the temperature of the hydrocarbons and allows individual temperature adjustment.

[0055] In various embodiments, the device includes a separation structure configured to receive hydrocarbons in the liquid phase. In various embodiments, the separation structure is configured to accommodate hydrocarbons in the liquid phase and / or the gas phase and allow the collection of cracked hydrocarbons with shorter chains. In various embodiments, the separation structure is configured to allow the hydrocarbons in the liquid phase to be agitated and / or heated to allow cracking. In various embodiments, the separation structure is configured to allow the removal of soot, debris, and / or carbon.

[0056] In various embodiments, the device includes a gas release pipe configured to receive hydrocarbons in the gas phase at a dispensing volume and convey the hydrocarbons in the gas phase; wherein the separation structure is configured to receive hydrocarbons in the gas phase through the gas release pipe at the upper part of the separation structure and receive hydrocarbons in the liquid phase at the lower part of the separation structure.

[0057] In various embodiments, at least one of the heating sections is configured such that the flow path from the heating section inlet to the heating section outlet extends at an angle of 0° to 45° with respect to the horizontal plane, preferably at an angle of 0° to 10° with respect to the horizontal plane, and the downstream end of the flow path is higher than the upstream end.

[0058] In various embodiments, at least one of the heating sections is configured such that its respective heating section inlet is lower than its heating section outlet

[0059] According to another aspect, a method of operating the apparatus as described in the above embodiments is provided.

[0060] Returning to Figure 1 the description, the assembly includes a heating structure 11 and a separation structure 12. The heating structure 11 is in communication with the separation structure 12 to feed fluid into the separation structure 12. Specifically, the heating structure 11 feeds a fluid containing cracked and uncracked hydrocarbons into the separation structure 12.

[0061] In some embodiments, the feed device 7 is arranged to fill the heating structure 11 with a material containing long-chain hydrocarbons such as waste plastic or crude oil. In a further embodiment, CaO and / or zeolite are provided as additives to the feed device. In some embodiments, the feed device 7 includes an actuator 8 for heating and / or conveying the material containing long-chain hydrocarbons. In some embodiments, the actuator is an auger 8 which is arranged to heat and / or convey the material containing long-chain hydrocarbons. In some embodiments, the auger 8 moves the material and the internal friction in the material causes the material to heat up and melt. In a further embodiment, the feed device 7 includes a heating device such as an electric heater and / or a heating device injected with a heating medium such as heat transfer oil. The feed device 7 conveys the material containing long-chain hydrocarbons to the heating structure 11.

[0062] The heating structure 11 receives the material containing long-chain hydrocarbons. In various embodiments, the heating structure includes at least one heating zone 1, 2, 3, 4. The heating zones 1, 2, 3, 4 are arranged to heat the material containing long-chain hydrocarbons to the cracking temperature. The heating zones 1, 2, 3, 4 are arranged to expose the material containing long-chain hydrocarbons that has reached the cracking temperature to a limited temperature increase. In other words, the material containing long-chain hydrocarbons above the cracking temperature is exposed to a temperature below a predetermined temperature above the temperature of the material. It has been found that by limiting the temperature increase, the yield of the available material containing hydrocarbons having the desired chain length produced by the operation of the assembly is increased and the amount of the resulting solid carbon is limited. In various embodiments, the heating zones 1, 2, 3, 4 are arranged to expose the material containing long-chain hydrocarbons to a predetermined temperature that is about 50 °C or lower, preferably about 40 °C or lower, preferably about 25 °C or lower higher than the temperature of the corresponding material containing long-chain hydrocarbons.

[0063] Hereinafter, the temperature to which the material containing long-chain hydrocarbons is exposed is referred to as the exposure temperature. However, the exposure temperature will have different values depending on the position in the assembly and the corresponding temperature of the material containing long-chain hydrocarbons.

[0064] In various embodiments, heating zones 1, 2, 3, 4 provide a flow path for a material containing long-chain hydrocarbons. Heating zones 1, 2, 3, 4 continuously or gradually increase the exposure temperature along the flow path. In some embodiments, heating zones 1, 2, 3, 4 provide at least one material flow tube for the material containing long-chain hydrocarbons. The material flows through the material flow tube generally in a first direction. Heating zones 1, 2, 3, 4 further provide heating tubes that contact the material flow tube along most of the length of heating zones 1, 2, 3, 4, such that heat can be transferred from the interior of the heating tubes into the material flow tube. A second tube provides a flow path for the heating medium.

[0065] In some of these embodiments, the heating medium flows in a direction opposite to the first direction, such that the flow of the material containing long-chain hydrocarbons along the first direction is heated while the flow of the heating medium along the second direction is cooled. In some of these embodiments, the temperature of the heating medium is controlled not to be higher than a predetermined final temperature of 50 °C when entering the heating tubes along heating zones 1, 2, 3, 4, and the temperature of the heating medium is controlled not to be higher than the temperature of the material containing long-chain hydrocarbons by 50 °C when entering heating zones 1, 2, 3, 4. In some embodiments, the temperature of the heating medium is controlled not to be higher than a predetermined final temperature of 40 °C when entering the heating tubes along heating zones 1, 2, 3, 4, and the temperature of the heating medium is controlled not to be higher than the temperature of the material containing long-chain hydrocarbons by 40 °C when entering heating zones 1, 2, 3, 4. In some embodiments, the temperature of the heating medium is controlled not to be higher than a predetermined final temperature of 25 °C when entering the heating tubes along heating zones 1, 2, 3, 4, and the temperature of the heating medium is controlled not to be higher than the temperature of the material containing long-chain hydrocarbons by 25 °C when entering heating zones 1, 2, 3, 4. In some embodiments, the temperature, velocity, and / or pressure of the heating medium in the heating tubes and / or the material containing long-chain hydrocarbons in the material flow tubes are controlled. In some embodiments, the heating tubes are sized such that the heating medium flowing through the heating tubes at a predetermined velocity and having a predetermined starting velocity will have predetermined temperature characteristics. In some embodiments, the material flow tube extends coaxially within the heating tube.

[0066] In some embodiments, heating zones 1, 2, 3, 4 include several heating segments, and each heating segment exposes the material containing long-chain hydrocarbons to a predetermined temperature. The heating segments are configured such that the material containing long-chain hydrocarbons flows continuously through each heating segment. Each heating segment exposes the material to a higher temperature than the previous heating segment. The heating segments are configured such that the exposure temperature when entering the corresponding heating segment does not exceed the temperature of the material containing long-chain hydrocarbons by 50 °C. In Figure 1 an embodiment, heating zones 1, 2, 3, 4 include four heating segments, and the present invention may include more or fewer heating segments in various embodiments.

[0067] Whether cracking occurs in the first heating section 1 depends not only on the temperature, but also on the long-chain hydrocarbons contained in the material, as well as other substances intentionally or inadvertently contained in the material, and the pressure of the material. In some cases, since other parameters do not promote cracking, cracking basically does not occur at low temperatures (such as between 200 °C and 250 °C). In such cases, the exposure temperature may be 50 °C higher than the material temperature. In some embodiments, the exposure temperature of the first heating section 1 may be 50 °C higher than the lowest temperature at which cracking basically occurs. In some embodiments, cracking only starts at 360 °C, and the exposure temperature is as high as 430 °C.

[0068] When leaving the first heating section 1, the material is transferred to a second heating section 2 downstream of the first heating section 1. The second heating section 2 exposes the material containing long-chain hydrocarbons to a higher exposure temperature than the first heating section 1, that is, the second exposure temperature. The second exposure temperature does not exceed a temperature 50 °C above the temperature of the material containing long-chain hydrocarbons. In various embodiments, the second exposure temperature does not exceed a temperature 40 °C above the temperature of the material containing long-chain hydrocarbons. In various embodiments, the second exposure temperature does not exceed a temperature 25 °C above the temperature of the material containing long-chain hydrocarbons. In various embodiments, the second exposure temperature is between 250 °C and 450 °C. In various embodiments, the second exposure temperature is between 300 °C and 400 °C. The material containing long-chain hydrocarbons flows through the second heating section 2 and is heated to the second exposure temperature.

[0069] In Figure 1 the embodiments, the material containing long-chain hydrocarbons is transferred from the second heating section 2 to a third heating section 3 downstream of the second heating section 2. The third heating section 3 exposes the material to a third exposure temperature. The third exposure temperature is higher than the second exposure temperature. The third exposure temperature does not exceed a temperature 50 °C above the material temperature. In various embodiments, the third exposure temperature does not exceed a temperature 40 °C above the temperature of the material containing long-chain hydrocarbons. In various embodiments, the third exposure temperature does not exceed a temperature 25 °C above the temperature of the material containing long-chain hydrocarbons. The material containing long-chain hydrocarbons flows through the third heating section 3 and is heated to the third exposure temperature.

[0070] The material containing long-chain hydrocarbons is transferred from the third heating section 3 to a fourth heating section 4 downstream of the third heating section 3. The fourth heating section 4 exposes the material to a fourth exposure temperature. The fourth exposure temperature does not exceed a temperature 50 °C above the material temperature.

[0071] In various embodiments, the fourth exposure temperature does not exceed a temperature 40 °C above the temperature of the material containing long-chain hydrocarbons. In various embodiments, the fourth exposure temperature does not exceed a temperature 25 °C above the temperature of the material containing long-chain hydrocarbons. The fourth exposure temperature basically determines the highest temperature of the long-chain hydrocarbons leaving the heating zone. The material containing long-chain hydrocarbons flows through the fourth heating section 4 and is heated to the fourth exposure temperature.

[0072] When a material containing long-chain hydrocarbons flows through the fourth heating section 4, some of the long-chain hydrocarbons undergo cracking. In some embodiments, when the material flows through the third heating section 3, some of the long-chain hydrocarbons undergo cracking. In some embodiments, when the material flows through the second heating section 2, some of the long-chain hydrocarbons undergo cracking. In some embodiments, when the material flows through the first heating section 1, some of the long-chain hydrocarbons undergo cracking. In principle, the hotter the heating section, the more cracking occurs. Once a large amount of long-chain hydrocarbons have been cracked, the heating section limits the exposure temperature to a maximum of 50 °C higher than the material temperature. Thus, the material containing long-chain hydrocarbons also contains cracked hydrocarbons. That is, the proportion of hydrocarbons with shorter chain lengths increases compared to the material before entering the heating zone. The material leaving the fourth heating section 4 is conveyed to the separation structure 12.

[0073] In various embodiments, the heating sections are composed of the same structure such that only one type of heating section can be used at each position in the heating section chain. In various embodiments, the heating sections are designed to heat to a temperature of 450 °C. In various embodiments, the heating sections are designed for an operating pressure between 0 bar and 150 bar. In a further embodiment, the heating sections are designed for an operating pressure between 0 bar and 80 bar, preferably for an operating pressure between 0 bar and 40 bar. In various embodiments, the heating sections are supplied with a liquid as the heating medium. In various embodiments, the heating sections are supplied with a heat transfer oil as the heating medium. In various embodiments, the selected hot oil has a boiling point higher than the operating temperature of the heating section at the operating pressure and / or a freezing point lower than 40 °C.

[0074] In a further embodiment, the throughput of the material containing long-chain hydrocarbons is adjusted to ensure that the material leaving the first to fourth heating sections reaches respective specific temperatures. For the first to third heating sections, the specific temperature is less than 50 °C lower than the exposure temperature of the subsequent respective heating sections. In various embodiments, the specific temperature is less than 40 °C lower than the exposure temperature of the subsequent respective heating sections. In various embodiments, the specific temperature is less than 25 °C lower than the exposure temperature of the subsequent respective heating sections. For the fourth heating section 4, the specific temperature is a predetermined maximum temperature.

[0075] The above applies mutatis mutandis to heating structures with more or fewer heating sections.

[0076] In some embodiments, there are backpressure control elements 5a, 5b downstream of the heating zones 1, 2, 3, 4. The backpressure control elements 5a, 5b are arranged to regulate the pressure of the material containing long-chain hydrocarbons in the heating zones. In various embodiments, the backpressure control elements control the throughput of the material through the heating zones. The backpressure control elements are arranged between the heating zones and the separation structure 12. The material containing long-chain hydrocarbons leaving the backpressure control elements 5a, 5b is conveyed to the separation structure 12. In some embodiments, the backpressure control elements include an adjustable valve 5a and a pressure sensor 5b. The pressure sensor 5b is configured to detect the pressure of the material in the heating zone. The adjustable valve 5a is configured to release the material as long as the pressure sensor 5b detects a pressure within a specific range. In some embodiments, the specific range is between 0 bar and 150 bar. In a further embodiment, the specific range is between 0 bar and 80 bar, preferably between 0 bar and 40 bar. In some embodiments, the specific range is about 20 bar. If the pressure of the material in the heating zone exceeds the said range, the valve 5a controls the throughput of the material. For example, if the pressure in the heating zone drops below the lower limit of the pressure range, the valve 5a reduces the throughput until the pressure in the heating zone builds up. If the pressure in the heating zone exceeds the upper limit, the valve 5a allows an increase in throughput until the pressure drops. In some embodiments, the valve 5a has the structure of a pressure relief valve, i.e., the valve 5a is held closed by a preloaded spring and, once the predetermined pressure is exceeded, the valve 5a opens towards the subsequent separation structure 12 and closes once the pressure drops below the predetermined pressure. In a further embodiment, the valve 5a is a gate valve that regulates the throughput by opening and closing, thereby regulating the pressure detected by the pressure sensor 5b. In some embodiments, the valve 5a is arranged to always allow a small throughput, in other words, the valve 5a is arranged not to close completely. In some embodiments, the valve 5a is driven by a motor (such as an electric motor, a pneumatic motor or a hydraulic motor).

[0077] A further aspect of the separation structure 12 and methods and structures for cracking long-chain hydrocarbons are set forth in WO 2021 / 053139A1.

[0078] The pressure of the heating zone is selected to keep more of the cracked material in the liquid phase. This is to avoid the material being in the gas phase, as the material in the gas phase would impede heat transfer through the material. In addition, the volume of the material changing from the liquid phase to the gas phase would increase significantly. Keeping more of the cracked material in the liquid phase avoids liquid material being driven through the material flow tube at a rate that would prevent the material from being heated as desired.

[0079] Once the material passes through the backpressure control element, the pressure in the material drops. In particular, more short-chain hydrocarbons produced by cracking evaporate into the gas phase, resulting in more hydrocarbons in the gas phase and some or all of the suppressed bubbles expanding.

[0080] Figure 2 Figure 2 shows an embodiment of the heating structure 11 in more detail. In this embodiment, the heating structure 11 includes a first heating section 1 and a second heating section 2.

[0081] The first heating section 1 includes a first material flow pipe 101, which has a first heating section inlet 102 and a first heating section outlet 103. The first material flow pipe 101 extends from the first heating section inlet 102 to the first heating section outlet 103 and provides a flow path for the molten long-chain hydrocarbon from the first heating section inlet 102 to the first heating section outlet 103. The first heating section 1 further includes a first heating appliance 113. The first heating appliance 113 is configured to release heat energy to the molten long-chain hydrocarbon in the first material flow pipe 101. In some embodiments, the first heating appliance 113 is an electric heater. In a further embodiment, the first heating appliance 113 is the shell of a shell-and-tube heat exchanger, and a fluid heating medium flows through the shell at or around the first material flow pipe 101. In some embodiments, the fluid heating medium enters the shell at a first heating medium inlet 111 adjacent to the first heating section outlet 103, and the fluid heating medium leaves the shell at a first heating medium outlet 112. In some embodiments, the shell includes baffles that direct the flow of the heating medium inside the shell. The first heating section 1 further includes a first distribution volume 110 upstream of the first material flow pipe 101 and a first disengaging volume 120 downstream of the first material flow pipe 101. If the first heating section 1 includes another material flow pipe in addition to the first material flow pipe 101, the flow path of the molten long-chain hydrocarbon branches into the material flow pipes of the first heating section 1 in the first distribution volume 110 and converges at the first disengaging volume 120.

[0082] In operation, the long-chain hydrocarbon is heated to a molten state and enters the first heating section 1 from the first heating section inlet 104. Then, the molten long-chain hydrocarbon passes through the first distribution volume 110 and enters the first material flow pipe 101 through the first heating section inlet 102. The heating appliance 113 further heats the molten long-chain hydrocarbon inside the first material flow pipe 101, as further explained above with respect to the first heating section 1. Then, the molten long-chain hydrocarbon passes through the first heating section outlet 103 and enters the first disengaging volume 120. Also as described above, some of the molten long-chain hydrocarbon may start to crack inside the first material flow pipe 101, so its evaporation temperature is within the operating temperature range inside the first material flow pipe 101. Therefore, the hydrocarbons in the gas phase form bubbles 1000 in the molten long-chain hydrocarbon. In the disengaging volume 120, the bubbles 1000 disengage from the long-chain hydrocarbon in the liquid phase 1001 and rise, such that the long-chain hydrocarbon in the liquid phase 1001 will occupy the lower part of the first disengaging volume 120, while the hydrocarbons in the gas phase 1002 will occupy the higher part of the first disengaging volume 120.

[0083] The second heating section 2 includes a second material flow pipe 202 having a second heating section inlet 212 and a second heating section outlet 213, and a third material flow pipe 203 having a third heating section inlet 222 and a third heating section outlet 223. The second material flow pipe 202 extends from the second heating section inlet 212 to the second heating section outlet 213. The third material flow pipe 203 extends from the third heating section inlet 222 to the third heating section outlet 223. The second heating section 2 further includes a second distribution volume 210 located upstream of the second material flow pipe 202 and the third material flow pipe 203 and a second disengaging volume 220 located downstream of the second material flow pipe 202 and the third material flow pipe 203. The flow path of the hydrocarbon along the second heating section 2 divides into the second material flow pipe 202 and the third material flow pipe 203 of the first heating section 1 in the second distribution volume 210 and converges at the second disengaging volume 220. The second heating section inlet 212 is arranged at a higher level than the third heating section inlet 222. In some embodiments, the second material flow pipe 202 is also substantially arranged at a higher level than the third material flow pipe 203.

[0084] The second heating section 2 includes a second heating appliance 233. The second heating appliance 233 is configured to release heat energy to the molten long-chain hydrocarbon in at least one of the second material flow pipe 202 and the third material flow pipe 203. The second heating appliance 233 mainly corresponds to the first heating appliance 113, but provides a higher temperature for the molten long-chain hydrocarbon, as further explained above with respect to the second heating section 2 and Figure 1 explained further. In some embodiments, the second heating appliance 233 includes a second heating medium inlet 231 adjacent to the second heating section outlet 213 and the third heating section outlet 223 and a second heating medium outlet 232 adjacent to the second heating section inlet 212 and the third heating section inlet 222. In operation, the heating medium circulates from the second heating medium inlet 231 to the second heating medium outlet 232. In a further embodiment, the heating medium has a negligible temperature drop, so the circulation direction is less relevant. In such embodiments, the heating medium can circulate in the opposite direction, thereby effectively circulating from the second heating medium outlet 232 to the second heating medium inlet 231.

[0085] In various embodiments, the heating structure 11 further includes a connecting pipe 150. In various embodiments, the connecting pipe 150 has a circular inner cross-section. The connecting pipe 150 connects the first heating section 1 and the second heating section 2, and is specifically used to transfer long-chain hydrocarbons in the liquid phase 1001 and hydrocarbons in the gas phase 1002 from the first heating section 1 to the second heating section 2. More specifically, in operation, the long-chain hydrocarbons in the liquid phase 1001 and the hydrocarbons in the gas phase 1002 leave the first disengaging volume 120 and pass through the connecting pipe 150 into the second distribution volume 210. In various embodiments, the connecting pipe 150 extends substantially horizontally between the first heating section 1 and the second heating section 2. In a further embodiment, the connecting pipe 150 extends at an angle of 0° to 45° with respect to the horizontal plane, preferably at an angle of 0° to 35° with respect to the horizontal plane, preferably at an angle of 0° to 25° with respect to the horizontal plane, preferably at an angle of 0° to 15° with respect to the horizontal plane, preferably at an angle of 0° to 10° with respect to the horizontal plane, and the downstream end of the connecting pipe 150 is higher than the upstream end.

[0086] In the second distribution volume 210, the long-chain hydrocarbons in the liquid phase 1001 and the hydrocarbons in the gas phase 1002 are split, either passing through the second heating section inlet 212 into the second material flow pipe 202 or passing through the third heating section inlet 222 into the third material flow pipe 203. Since the second heating section inlet 212 is arranged at a position higher than the third heating section inlet 222, the hydrocarbons in the gas phase 1002 are more likely to pass through the second heating section inlet 212 into the second material flow pipe 202, and the long-chain hydrocarbons in the liquid phase 1001 are more likely to pass through the third heating section inlet 222 into the third material flow pipe 203. In this way, the proportion of the hydrocarbons in the gas phase 1002 contained in the second material flow pipe 202 is relatively high, while the proportion of the long-chain hydrocarbons in the liquid phase 1001 contained in the third material flow pipe 203 is relatively high. Therefore, since some of the hydrocarbons in the gas phase 1002 have been removed from the long-chain hydrocarbons in the liquid phase 1001 in the third material flow pipe 203, the long-chain hydrocarbons in the liquid phase 1001 in the third material flow pipe 203 can be heated more effectively. The hydrocarbons in the gas phase 1002 in the second material flow pipe 202 bypass the long-chain hydrocarbons in the liquid phase 1001 and reach the second heating section outlet 205 faster.

[0087] The second heating means 233 further heats the long-chain hydrocarbons inside the third material flow tube 203, as further explained above with respect to the second heating section 2. The molten long-chain hydrocarbons then enter the second disengagement volume 220 primarily through the third heating section outlet 223. Also as described above, some long-chain hydrocarbons may begin to crack inside the third material flow tube 203, so their evaporation temperature is within the operating temperature range inside the third material flow tube 203. Therefore, the hydrocarbons in the gas phase form further bubbles 1000 in the long-chain hydrocarbons in the liquid phase 1001. In the disengagement volume 220, the bubbles 1000 rise so that the long-chain hydrocarbons in the liquid phase 1001 occupy the lower part of the disengagement volume 220, and the bubbles 1000 from the third material flow tube 203 merge with the hydrocarbons in the gas phase 1002 from the second material flow tube 202. The hydrocarbons in the gas phase 1002 occupy the higher part of the second disengagement volume 220. Likewise, in the disengagement volume 220 , the long-chain hydrocarbons in the liquid phase 1001 from the second material flow line 203 are combined with the long-chain hydrocarbons in the liquid phase 1001 from the third material flow line 203 .

[0088] The long-chain hydrocarbons in the liquid phase 1001 and the hydrocarbons in the gas phase 1002 leave the second disengaging volume 220 through the second heating stage outlet 205, thereby leaving the second heating stage 2. In one embodiment, the second heating stage outlet 205 is connected to the third heating stage 3 and one or more additional heating stages. In another embodiment, the back pressure control element 5a, 5b and / or the separation structure 12 further downstream is immediately adjacent to the second heating stage outlet 205.

[0089] Figure 2Embodiments further show that the first heating section 1 is generally lower than the second heating section 2. Specifically, the inlet 104 of the first heating section is substantially flush with and / or at the same level as the lower part or bottom of the first distribution volume 110, the top of the separation volume 120 is substantially flush with and / or at the same level as the connecting pipe 150, and the connecting pipe 150 is substantially flush with and / or at the same level as the lower part or bottom of the second distribution volume 210. In addition, the outlet 205 of the second heating section is substantially flush with and / or at the same level as the top of the second separation volume 220. The connecting pipe 150 preferably extends horizontally or at an angle between 0° and 45° with respect to the horizontal plane, preferably at an angle between 0° and 35° with respect to the horizontal plane, preferably at an angle between 0° and 25° with respect to the horizontal plane, preferably at an angle between 0° and 15° with respect to the horizontal plane, preferably at an angle between 0° and 10° with respect to the horizontal plane, and the downstream end of the connecting pipe 150 is higher than the upstream end. Similarly, the first material flow pipe 101, the second material flow pipe 202, and the third material flow pipe 203 preferably extend horizontally or at an angle between 0° and 10°, and the downstream end is higher than the corresponding upstream end. Therefore, the hydrocarbons in the gas phase 1002 tend to rise from the inlet 104 of the first heating section to the outlet 205 of the second heating section through the first heating section 1 and the second heating section 2, and preferably further rise to the back pressure control elements 5a, 5b and / or the separation structure 12 further downstream. If necessary, the long-chain hydrocarbons in the liquid phase 1001 can be discharged through the inlet 104 of the first heating section. In a further embodiment, each subsequent heating section is connected to the corresponding previous connecting pipe through the bottom of the corresponding distribution volume and to the subsequent connecting pipe through the top of the corresponding separation volume.

[0090] It has been found that it is advantageous to separate the hydrocarbons in the gas phase 1002 from the long-chain hydrocarbons in the liquid phase 1001, because it allows the hydrocarbons in the gas phase 1002 to quickly pass through the second heating section 2, while the long-chain hydrocarbons in the liquid phase 1001 are better heated by the second heating appliance 233, because the interference of the hydrocarbons in the gas phase 1002 with the heat transfer into and through the long-chain hydrocarbons in the liquid phase 1001 is less.

[0091] In various embodiments, the heating structure 11 is configured to maintain the separation of the hydrocarbons in the gas phase 1002 from the long-chain hydrocarbons in the liquid phase 1001 in the first separation volume 120, the connecting pipe 150, and the second distribution volume 210. Specifically, the first separation volume 120, the connecting pipe 150, and the second distribution volume 210 are configured to prevent the hydrocarbons in the gas phase 1002 from mixing with the long-chain hydrocarbons in the liquid phase 1001.

[0092] In various embodiments, the connecting pipe 150 has a circular cross-section with a diameter smaller than the diameter of the first separation volume 120, and / or the cross-sectional area of the connecting pipe 150 is smaller than the cross-sectional area of the first separation volume 120. Due to the smaller cross-section at the connecting pipe 150, when the mass flow rate through the first separation volume 120 and the connecting pipe 150 is substantially constant, the hydrocarbons in the gas phase 1002 and the long-chain hydrocarbons in the liquid phase 1001 have a relatively high velocity when passing through the connecting pipe 150. Thus, the hydrocarbons in the gas phase 1002 and the long-chain hydrocarbons in the liquid phase 1001 stay in the connecting pipe 150 for a shorter time. Therefore, the hydrocarbons in the gas phase 1002 and the long-chain hydrocarbons in the liquid phase 1001 are less cooled during passing through the connecting pipe 150.

[0093] In some embodiments, the first heating section 1 and the second heating section 2 are configured in a U-shape such that the first heating section 1 has hydrocarbon flow in a first direction along the first material flow pipe 101, and the second heating section 2 has hydrocarbon flow in a second direction along the second material flow pipe 202 and the third material flow pipe 203, the second direction being substantially parallel to but opposite to the first direction. The advantage of this configuration is that the first heating section inlet 104 is adjacent to the second heating section outlet 205. Thus, the support structures of the first heating section inlet 104 and the second heating section outlet 205 can be arranged to be fixed, while the respective opposite ends of the first heating section 1 and the second heating section 2 having the first separation volume 120, the connecting pipe 150, and the second distribution volume 210 can move more freely under thermal expansion and contraction. However, the connecting pipe 150 also stretches and contracts under the influence of heat. In various embodiments, the diameter of the connecting pipe 150 is significantly smaller than the diameters of the first separation volume 120 and the second distribution volume 210. This makes the connecting pipe 150 less rigid and the connecting pipe 150 can be bent more, and the tendency to bend the first heating section 1 and the second heating section 2 will be lower. However, the lower limit of the connecting pipe diameter is determined by the minimum inner diameter required to keep the gas phase and the liquid phase separated, as discussed further above. In further embodiments, any number of heating sections are arranged, where any two adjacent heating sections are substantially parallel and have opposite flow directions in their respective material flow pipes.

[0094] In various embodiments, the connecting pipe 150 includes an electric heating element. In some embodiments, the electric heating element allows heating of hydrocarbons in the gas phase 1002 and long-chain hydrocarbons in the liquid phase 1001. If the heating section is stationary for a period of time, little newly heated material follows and the material in the connecting pipe 150 solidifies. In various embodiments, the electric heating element is configured to maintain the hydrocarbons in the gas phase 1002 and the long-chain hydrocarbons in the liquid phase 1001 from solidifying. Thus, the electric heating enables the hydrocarbons in the gas phase 1002 and the long-chain hydrocarbons in the liquid phase 1001 to remain in a processable state. In a further embodiment, a heat transfer oil is used to heat the connecting pipe 150. In various embodiments, this allows maintaining the hydrocarbon temperature and the corresponding liquid and gas phases when fluid flow stops (e.g., during shutdown maintenance).

[0095] As long as the flow pattern of the gas phase and the liquid phase is one of the bubble, plug, stratified, wavy or slug patterns, the long-chain hydrocarbons in the liquid phase 1001 and the hydrocarbons in the gas phase 1002 remain separated even when flowing in a common pipe. These patterns are also explained in Figure 6-24 of the seventh edition of "PERRY'S CHEMICAL ENGINEERS’ HANDBOOK". To keep the gas phase and the liquid phase separated, the assembly for cracking long-chain hydrocarbons should be configured accordingly. Specifically, the connecting pipe should extend at least partially horizontally or at an angle between 0° and 45° with respect to the horizontal plane, preferably at an angle between 0° and 35° with respect to the horizontal plane, preferably at an angle between 0° and 25° with respect to the horizontal plane, preferably at an angle between 0° and 15° with respect to the horizontal plane, preferably at an angle between 0° and 10° with respect to the horizontal plane. The connecting pipe 150 should have a certain minimum inner diameter. Alternatively or additionally, at least one of the mass flow rates of the molten long-chain hydrocarbons entering the inlet 104 of the first heating section, the long-chain hydrocarbons in the liquid phase 1001, and the hydrocarbons in the gas phase 1002 should not exceed certain limits. Alternatively or additionally, the pressure of the material in the heating zone can be adjusted accordingly. The pressure of the material in the heating zone affects the hydrocarbon fraction in the gas phase 1002 because if the pressure increases, the evaporation temperature also increases. That is, the higher the pressure, the less hydrocarbons are converted to the gas phase. For example, assuming the temperature is between 250 °C and 450 °C, for a mass flow rate between 1000 kg / h and 20000 kg / h, a gas content between 1 mass% and 50 mass%, and a pressure between 100 kPa and 8100 kPa, the inner diameter of the connecting pipe 150 should be at least 50 mm. In various embodiments, the connecting pipe 150 provides a circular inner cross-section with a diameter between 50 and 500 mm, preferably between 50 and 80 mm. However, the inner diameter of the connecting pipe may also be predetermined by other factors such as thermal expansion characteristics, and one or more other parameters, namely the raw material composition and particle size, temperature, mass flow rate, gas content or pressure, are adjusted accordingly.

[0096] If the assembly for cracking long-chain hydrocarbons is configured with one or more parameters outside of these ranges, the flow pattern may become spray, thereby forming an aerosol or annular, i.e., the liquid stream is substantially surrounded by the gas stream. These flow patterns will impede the separation of the long-chain hydrocarbons in the liquid phase 1001 from the hydrocarbons in the gas phase 1002, such that more long-chain hydrocarbons in the liquid phase 1001 will ultimately enter a higher subsequent material flow tube, such as the second material flow tube 202, while more hydrocarbons in the gas phase 1002 will ultimately enter a lower subsequent material flow tube, such as the third material flow tube 203.

[0097] Figure 3 Another embodiment of the heating structure 11 is shown. In this embodiment, the heating structure 11 includes a first heating section 1 and a second heating section 2 that are communicatively coupled to each other through a connecting tube 150. In various embodiments, the connecting tube 150 extends substantially horizontally between the first heating section 1 and the second heating section 2. In a further embodiment, the connecting tube 150 extends at an angle of 0° to 45° with respect to the horizontal plane, preferably at an angle of 0° to 35° with respect to the horizontal plane, preferably at an angle of 0° to 25° with respect to the horizontal plane, preferably at an angle of 0° to 15° with respect to the horizontal plane, preferably at an angle of 0° to 10° with respect to the horizontal plane, and the downstream end of the connecting tube 150 is higher than the upstream end. Corresponding to Figure 2 the configuration of the embodiment, the first heating section 1 and the second heating section 2 each respectively include a first distribution volume 110 and a second distribution volume 210, and respectively a first separation volume 120 and a second separation volume 220. In Figure 3 the embodiment shown, the first heating section 1 includes at least two first material flow tubes 101a. The first material flow tubes 101a extend and provide a flow path from the first distribution volume 110 to the first separation volume 120.

[0098] It has been found that the material containing long-chain hydrocarbons entering the heating section 1 from the feed device 7 may contain gases, such as hydrocarbons in the gas phase 1002, which depends particularly on the material, pressure and temperature in the feed device 7. In a further embodiment, the first material flow tube 101a at least includes an upper first material flow tube having an upper first heating section inlet and an upper first heating section outlet, and a lower first material flow tube having a lower first heating section inlet and a lower first heating section outlet. The upper material flow tube extends from the upper first heating section inlet to the upper first heating section outlet. The lower first material flow tube extends from the lower first heating section inlet to the lower first heating section outlet. In these further embodiments, the upper first heating section inlet is located above the lower first heating section inlet, such that the gas entering the heating section 1 instead passes through the upper first material flow tube through the first heating section 1 into the first separation volume 120, and the long-chain hydrocarbons in the liquid phase 1001 instead pass through the lower first material flow tube through the first heating section 1 into the first separation volume 120. In some embodiments, the upper first material flow tube is also substantially arranged at a higher position than the lower first material flow tube.

[0099] In various embodiments, Figure 3 the first heating section 1 of includes a plurality of first material flow tubes 101a. Some of the plurality of first material flow tubes 101a are arranged at a different level from the other first material flow tubes among the plurality of first material flow tubes 101a.

[0100] Corresponding to Figure 2 the embodiment of, the first heating section 1 includes a first heating appliance 113 configured to release heat energy to the molten long-chain hydrocarbons in the first material flow tube 101. In some embodiments, the heating appliance 113 is configured such that a fluid heating medium enters the heating appliance 113 at the first heating medium inlet 111 adjacent to the first separation volume 120, and the fluid heating medium leaves the heating appliance 113 at the first heating medium outlet 112 adjacent to the first distribution volume 110. In various embodiments, it is generally assumed that the aspects not discussed for Figure 3 are substantially corresponding to Figure 2 relatively.

[0101] In Figure 3In an embodiment, the second heating section 2 further includes a plurality of second and third material flow tubes 201. The second and third material flow tubes 201 respectively include a second heating section inlet 201a and a third heating section inlet 201b. The second and third material flow tubes 201 extend from the second heating section inlet 201a and the third heating section inlet 201b at the second distribution volume 210 to the second and third heating section outlets 201c at the second disengaging volume 220. In various embodiments, the second heating section inlet 201a is disposed near the top of the distribution volume 210. In various embodiments, the third heating section inlet is disposed lower than the second heating section inlet 201a and / or near the bottom of the second distribution volume 210.

[0102] The second heating section 2 includes a second heating appliance 233. The second heating appliance 233 is configured to release heat energy to the molten long-chain hydrocarbons in at least one of the second and third material flow tubes 201. The second heating appliance 233 mainly corresponds to the first heating appliance 113, but provides a higher temperature for the molten long-chain hydrocarbons, as further explained above. In some embodiments, the second heating appliance 233 includes a second heating medium inlet 231 and a second heating medium outlet 232, similar to Figure 2 the configuration discussed in the embodiment of

[0103] In operation, molten long-chain hydrocarbons enter the first heating section 1 at the inlet 104 of the first heating section and enter the first distribution volume 110. In the first distribution volume 110, the molten long-chain hydrocarbons are split into at least two first material flow tubes 101a and pass through towards the first disengaging volume 120. The molten long-chain hydrocarbons heated to their respective cracking temperatures start to crack and evaporate. The evaporated hydrocarbons will form bubbles 1000 in at least two first material flow tubes 101a. The molten long-chain hydrocarbons and the bubbles 1000 enter the first disengaging volume 120. In the disengaging volume 120, the bubbles 1000 will rise such that the long-chain hydrocarbons in the liquid phase 1001 will occupy the lower part of the first disengaging volume 120, while the hydrocarbons in the gas phase 1002 will occupy the higher part of the first disengaging volume 120. In various embodiments, the connecting pipe 150 is configured to maintain the separation of the hydrocarbons in the liquid phase 1001 from the hydrocarbons in the gas phase 1002 within a specified range of process parameters, such as the temperature, mass flow rate, gas content, and / or pressure of the hydrocarbons inside the heating structure 11. The hydrocarbons in the liquid phase 1001 and the hydrocarbons in the gas phase 1002 enter the second distribution volume 210 through the connecting pipe 150, where they are split into the second heating section inlet 201a and the third heating section inlet 201b. In various embodiments, the hydrocarbons in the liquid phase 1001 pass through the lower part or bottom of the second distribution volume 210, while the hydrocarbons in the gas phase 1002 pass through the higher part or top of the second distribution volume 210. In various embodiments, the second heating section inlet 201a is mainly arranged to receive the hydrocarbons in the gas phase 1002, and the third heating section inlet 201b is mainly arranged to receive the hydrocarbons in the liquid phase 1001.

[0104] Accordingly, the hydrocarbons in the gas phase 1002 are mainly conveyed from the second heating section inlet 201a through the second material flow tube 201 and through the second heating section outlet 201c to the second disengaging volume 220. In various embodiments, the second heating section outlet 201c is arranged to output the hydrocarbons in the gas phase 1002 to the upper part of the second disengaging volume 220 to avoid mixing of the hydrocarbons in the gas phase 1002 with the hydrocarbons in the liquid phase 1001 in the lower part of the second disengaging volume 220.

[0105] The hydrocarbons in the liquid phase 1001 are mainly transferred from the inlet 201b of the third heating section through the third material flow pipe 201 and through the outlet 201c of the third heating section to the second separation volume 220. In various embodiments, the outlet 201c of the third heating section is arranged to output the hydrocarbons in the liquid phase 1001 to the lower part of the second separation volume 220 to avoid mixing of the hydrocarbons in the liquid phase 1001 with the hydrocarbons in the gas phase 1002 in the upper part of the second separation volume 220. As further explained above, the operating temperature of the second heating section 2 is higher than that of the first heating section 1. Therefore, other long-chain hydrocarbons in the liquid phase 1001 reach the temperature at which they tend to crack, causing their evaporation temperature to decrease. Due to the higher temperature of the second heating section 2, other long-chain hydrocarbons in the liquid phase 1001 evaporate and turn into the gas phase. Therefore, additional evaporated hydrocarbons form further bubbles 1000 and are transferred together with the long-chain hydrocarbons in the liquid phase 1001 to the second separation volume 220. In the second separation volume 220, the bubbles 1000 separate from the long-chain hydrocarbons in the liquid phase 1001 and rise, such that the long-chain hydrocarbons in the liquid phase 1001 will occupy the lower part of the second separation volume 220, while the bubbles 1000 merge with the hydrocarbons in the gas phase 1002 from the second material flow pipe 201 and occupy the higher part of the second separation volume 220. Therefore, the hydrocarbon fraction in the gas phase 1002 increases by mass, while the long-chain hydrocarbon fraction in the liquid phase 1001 decreases by mass.

[0106] As previously described, the long-chain hydrocarbons in the liquid phase 1001 and the hydrocarbons in the gas phase 1002 leave the second separation volume 220 through the outlet 205 of the second heating section, and thus leave the second heating section 2. In one embodiment, the outlet 205 of the second heating section is connected to the third heating section 3 and one or more additional heating sections. In another embodiment, the backpressure control elements 5a, 5b and / or the separation structure 12 are arranged immediately downstream of the outlet 205 of the second heating section.

[0107] Figure 4 Yet another embodiment of the heating structure 11 is shown. In such embodiments, the heating structure 11 includes a first heating section 1, a second heating section 2 and a third heating section 3. The first heating section 1 and the second heating section 2 are communicatively coupled to each other through an upper first connection pipe 151 and a lower first connection pipe 152. The second heating section 2 and the third heating section 3 are communicatively coupled to each other through an upper second connection pipe 251 and a lower second connection pipe 252. Corresponding to Figure 2 and Figure 3 the configuration of the embodiment, the first heating section 1, the second heating section 2 and the third heating section 3 each respectively include a first distribution volume 110, a second distribution volume 210 and a third distribution volume 310, and respectively a first separation volume 120, a second separation volume 220 and a third separation volume 320.

[0108] In Figure 4In the illustrated embodiments, the first heating section 1 includes at least two first material flow tubes 101a. In various embodiments, Figure 4 the first heating section 1 includes a plurality of first material flow tubes 101a. The first material flow tubes 101a extend and provide a flow path from the first distribution volume 110 to the first disengaging volume 120. The first heating section 1 includes a first heating medium inlet 111 and a first heating medium outlet 112 for circulating a heating medium to dissipate heat energy to the molten long-chain hydrocarbons in at least one of the at least two first material flow tubes 101a. In a further embodiment, at least two of the first material flow tubes 101a are electrically heated.

[0109] In Figure 4 the embodiment, the second heating section 2 further includes a plurality of second and third material flow tubes 201. Figure 4 The structure of the plurality of second and third material flow tubes 201 of Figure 3 is substantially corresponding to the structure of the plurality of second and third material flow tubes 201 of

[0110] so some details are omitted here. The second and third material flow tubes 201 extend and provide a flow path from the second distribution volume 210 to the second disengaging volume 220. In various embodiments, the second material flow tubes 201 extend and provide a flow path from the top of the second distribution volume 210 to the top of the second disengaging volume 220. In various embodiments, the third material flow tubes 201 extend and provide a flow path from the bottom of the second distribution volume 210 to the bottom of the second disengaging volume 220. The second heating section 2 includes a second heating medium inlet 231 and a second heating medium outlet 232 for circulating a heating medium to dissipate heat energy to the molten long-chain hydrocarbons in at least one of the second and third material flow tubes 201. In a further embodiment, at least one of the second and third material flow tubes 201 is electrically heated. The heating of the second and third material flow tubes 201 mainly corresponds to the heating of the first material flow tubes 101a, but provides a higher temperature for the long-chain hydrocarbons in the liquid phase 1001 and / or the hydrocarbons in the gas phase 1002, as further explained above.

[0111] In Figure 4In an embodiment, the third heating section 3 further includes a plurality of fourth material flow tubes 301. The fourth material flow tubes 301 extend and provide a flow path from the third distribution volume 310 to the third disengaging volume 320. In various embodiments, a portion of the fourth material flow tubes 301 extends and provides a flow path from the top of the third distribution volume 310 to the top of the third disengaging volume 320. In various embodiments, a portion of the fourth material flow tubes 301 extends and provides a flow path from the bottom of the third distribution volume 310 to the bottom of the third disengaging volume 320. The structure of the plurality of fourth material flow tubes 301 of the third heating section 3 corresponds substantially to the structure of the plurality of second and third material flow tubes 201 of the second heating section 2, and will not be described in detail here. The differences will be explained below.

[0112] The third heating section 3 includes a third heating medium inlet 331 and a third heating medium outlet 332 for circulating a heating medium to dissipate heat energy to the molten long-chain hydrocarbons in at least some of the fourth material flow tubes 301. In a further embodiment, at least some of the fourth material flow tubes 301 are electrically heated. The heating of the fourth material flow tubes 301 corresponds mainly to the heating of the second and third material flow tubes 201, but provides a higher temperature for the long-chain hydrocarbons in the liquid phase 1001 and / or the hydrocarbons in the gas phase 1002, as further explained above.

[0113] In Figure 4 an embodiment, the first disengaging volume 120 is in fluid communication with the second distribution volume 210 through an upper first connecting tube 151 and a lower first connecting tube 152. The upper first connecting tube 151 provides a fluid connection from the upper part of the first disengaging volume 120 to the upper part of the second distribution volume 210. The lower first connecting tube 152 provides a fluid connection from the lower part of the first disengaging volume 120 to the lower part of the second distribution volume 210.

[0114] In operation, the molten long-chain hydrocarbons are heated in the first material flow pipe 101a and, as described above, bubbles of cracked hydrocarbons in the gas phase are formed. In the disengaging volume 120, the bubbles 1000 disengage from the long-chain hydrocarbons in the liquid phase 1001 and rise, such that the long-chain hydrocarbons in the liquid phase 1001 will occupy the lower part of the first disengaging volume 120, while the hydrocarbons in the gas phase 1002 will occupy the upper part of the first disengaging volume 120. The hydrocarbons in the gas phase 1002 thus pass from the upper part of the first disengaging volume 120 through the upper first connecting pipe 151 to the upper part of the second distribution volume 210. The long-chain hydrocarbons in the liquid phase 1001 pass from the lower part of the first disengaging volume 120 through the lower first connecting pipe 152 to the lower part of the second distribution volume 210. Thus, when the long-chain hydrocarbons in the liquid phase 1001 and the hydrocarbons in the gas phase 1002 pass through separate pipes from the first heating section 1 to the second heating section 2, the separation of the liquid phase and the gas phase can be more easily maintained even if one or more parameters such as temperature, mass flow rate, gas content, pipe diameter or pressure are outside the above ranges. This particularly also allows for a higher mass flow rate or a smaller diameter or cross-section of the upper first connecting pipe 151 and the lower first connecting pipe 152.

[0115] Similarly, the second disengaging volume 220 is in fluid communication with the third distribution volume 310 through the upper second connecting pipe 251 and the lower second connecting pipe 252. The upper second connecting pipe 251 provides a fluid connection from the upper part of the second disengaging volume 220 to the upper part of the third distribution volume 310. The lower second connecting pipe 252 provides a fluid connection from the lower part of the second disengaging volume 220 to the lower part of the third distribution volume 310.

[0116] In various embodiments, the third heating section 3 is communicatively coupled to the separation structure 12 through the upper third connecting pipe 351 and the lower third connecting pipe 352. The upper third connecting pipe 351 provides a fluid connection from the upper part of the third disengaging volume 320 to the upper part of the separation structure 12. The lower third connecting pipe 352 provides a fluid connection from the lower part of the third disengaging volume 320 to the lower part of the separation structure 12. In operation, the upper part of the separation structure 12 is mainly filled with the hydrocarbons in the gas phase 1002, while the lower part of the separation structure 12 is mainly filled with the hydrocarbons in the liquid phase 1001.

[0117] Although it is not desirable for the long-chain hydrocarbons in the liquid phase 1001 to mix with the hydrocarbons in the gas phase 1002 during heating in the heating sections 1, 2, 3, 4, it is preferred that the long-chain hydrocarbons in the liquid phase 1001 and the hydrocarbons in the gas phase 1002 be mixed before entering the separation structure 12. The pressure across the backpressure control elements 5a, 5b drops significantly. When passing through the backpressure control elements 5a, 5b downstream of the heating sections 1, 2, 3, 4, the pressure drop accelerates the flow of the long-chain hydrocarbons in the liquid phase 1001 and the hydrocarbons in the gas phase 1002 to an order of magnitude of the speed of sound in the gas phase. This results in significant mixing of the liquid and gas phases. Preferably, the pipe section guiding the hydrocarbons to the separation structure is vertically arranged and / or narrow. Such a vertical and / or narrow configuration also facilitates the mixing of the liquid and gas phases.

[0118] Figure 5 Another embodiment of the heating structure 11 is shown. In this embodiment, the heating structure 11 includes a first heating section 1, a second heating section 2, and a third heating section 3. The first heating section 1 and the second heating section 2 are communicatively coupled to each other through a lower first connecting pipe 152. The second heating section 2 and the third heating section 3 are communicatively coupled to each other through a lower second connecting pipe 252. Figure 5 The same numbers in Figure 4 correspond to the numbers in

[0119] In various embodiments, the first disengaging volume 120 and / or the second disengaging volume 220 are in fluid communication with the separation structure 12 to feed the hydrocarbons in the gas phase 1002 into the separation structure 12. In various embodiments, the third disengaging volume 320 is in fluid communication with the separation structure 12 to feed the hydrocarbons in the gas phase 1002 into the separation structure 12. In various embodiments, the hydrocarbons in the gas phase 1002 from the first disengaging volume 120, the second disengaging volume 220, and / or the third disengaging volume 320 are fed into the upper part of the separation structure 12. In Figure 5 embodiments, the heating structure 11 includes a gas release pipe 53. The gas release pipe 53 fluidly connects the first disengaging volume 120, the second disengaging volume 220, and / or the third disengaging volume 320 to the upper part of the separation structure 12. In operation, the upper part of the separation structure 12 is substantially filled with the hydrocarbons in the gas phase 1002. In various embodiments, the first disengaging volume 120, the second disengaging volume 220, and / or the third disengaging volume 320 are respectively connected to the gas release pipe 53 through a first gas discharge pipe 153, a second gas discharge pipe 253, and / or a third gas discharge pipe 353. In various embodiments, the first gas discharge pipe 153, the second gas discharge pipe 253, and / or the third gas discharge pipe 353 respectively provide a fluid connection from the upper part of the first disengaging volume 120, the second disengaging volume 220, and / or the third disengaging volume 320 to the gas release pipe 53.

[0120] The waste plastic raw materials of the present invention preferably include polyethylene and / or polypropylene plastics. Preferably, the total of polyethylene and polypropylene in the raw materials is at least 50% by weight, more preferably at least 60% by weight, still more preferably at least 75% by weight, and most preferably at least 90% by weight, based on the weight of the raw materials. These materials account for a large part of domestic plastic waste and can be pyrolyzed. The preferred plastics as raw materials are polyethylene or polypropylene.

[0121] The raw materials may also include polyvinyl chloride plastics. However, the content of PVC can preferably be limited to less than 10% by weight, preferably less than 5% by weight. The content of PVC can be greater than 1% by weight, more preferably greater than 5% by weight. It is preferably effectively absent of PVC in the raw materials.

[0122] The raw materials may further include polyethylene terephthalate plastics, preferably greater than 3% by weight of polyethylene terephthalate plastics, more preferably greater than 4% by weight. The raw materials preferably contain at most 20% by weight of PET plastics. The content of polyethylene terephthalate plastics is preferably up to 10% by weight, more preferably 5% by weight.

[0123] The raw materials can contain up to 100% by weight of polystyrene plastics. In an embodiment, the raw materials can contain at least 5% by weight, more preferably 20% by weight, still more preferably 50% by weight of polystyrene.

[0124] The pyrolysis temperature can vary within a limited range, depending on factors such as the raw material composition and operating pressure. Preferably, the plastic material is heated to a pyrolysis temperature of 360 °C or higher, about 390 °C or higher, more preferably about 400 °C or higher, up to about 450 °C, although higher temperatures up to about 500 °C or about 550 °C can also be implemented. Plastic pyrolysis may start at about 360 °C, so such temperatures can also be considered. However, at temperatures of about 390 °C or above, the pyrolysis is more significant, which may make the process more economically attractive.

[0125] As used herein, the term "pyrolysis zone" refers to the region where the material processed by the process or system (e.g., waste plastics or their derivatives produced by pyrolysis in the process or system) is at the pyrolysis temperature, for example, a temperature equal to or higher than 360 °C, more preferably a temperature equal to or higher than 390 °C, still more preferably a temperature equal to or higher than 400 °C. The pyrolysis zone is preferably a region where the temperature of the material processed in the process or system is from about 360 °C to about 550 °C, more preferably from about 390 °C to about 500 °C, still more preferably from about 400 °C to about 500 °C. The process and system can include pyrolysis zones with different activities. For example, there may be a main pyrolysis zone where most of the pyrolysis occurs, and its temperature is preferably higher than 390 °C, and a secondary pyrolysis zone where the temperature is higher than 360 °C but lower than 390 °C. The pyrolysis zone is the region of the system, the equipment process where pyrolysis occurs, or the region where pyrolysis conditions are generated.

[0126] In the usual understanding, pyrolysis is carried out under anaerobic conditions, most preferably under an inert atmosphere. Nitrogen can provide an inert atmosphere. Before startup, the system can be purged with nitrogen to at least provide an initial inert atmosphere.

[0127] The present invention preferably produces one or more hydrocarbon products, preferably wherein the hydrocarbon products include one or more of the following: butane, propane, kerosene, diesel oil, fuel oil; light distillates such as LPG, gasoline, naphtha or mixtures thereof; middle distillates such as kerosene, jet fuel, diesel oil or mixtures thereof; heavy distillates and residue oils such as fuel oil, lubricating oil, paraffin wax, wax, asphalt or mixtures thereof. The hydrocarbon products can be saturated, unsaturated, straight-chain, cyclic or aromatic. Further products can include non-condensable gases including methane, ethane, ethylene and / or other small molecules. The products can be used as a raw material source for a steam cracking unit for plastic manufacturing.

[0128] The term "non-condensate" or "non-condensable gas" has various names and refers to those hydrocarbon fractions that are too volatile to condense in the distillation section and which can (preferably) leave the process in gaseous form. It is generally considered that the non-condensable hydrocarbons in the pyrolysis process have from about 1 to about 7 carbon atoms. Non-condensates can include saturated, unsaturated, straight-chain, cyclic and / or aromatic hydrocarbons.

[0129] The term "light hydrocarbon" "LHC" has various names and refers to a hydrocarbon fraction that can be condensed in the process and can thus be obtained as a liquid, but which contains short-chain molecules. It is generally considered that the LHC in the pyrolysis process has from about 3 to about 8 carbon atoms and may also contain a smaller fraction of C2 molecules and / or C10 molecules. LHC can include saturated, unsaturated, straight-chain, cyclic and / or aromatic hydrocarbons.

[0130] The term "heavy hydrocarbon" "HHC" has various names and refers to a hydrocarbon fraction that can be condensed in the process and can thus be obtained as a liquid, and whose molecular chain composition is generally longer than that of LHC. It is generally considered that the HHC in the pyrolysis process has at least about 7 carbon atoms (possibly containing a smaller fraction of C6 molecules), preferably at most about 35 carbon atoms. Preferred ranges can include low-range products with about 7 to about 20 carbon atoms, possibly with a smaller fraction of C6 and / or C21 molecules. For low-range products, the final boiling point of HHC can be about 430 °C. Another preferred range can include medium-range products with about 8 to about 28 carbon atoms. For medium-range products, the final boiling point of HHC can be about 450 °C. Another preferred range can include high-range products with about 10 to about 35 carbon atoms. For high-range products, the final boiling point of HHC can be about 550 °C. HHC can include saturated, unsaturated, straight-chain, cyclic and / or aromatic hydrocarbons.

[0131] Readers familiar with the petrochemical industry will understand that during the distillation process, there may be some variations in the boundaries between non-condensables, LHC, and HHC. The overlap and / or variations may depend on the temperature, pressure, and flow rate settings chosen, etc., and the product specifications may be adjusted to suit the desired product quality.

[0132] All documents cited in the specific embodiments of the present invention are hereby incorporated by reference in their relevant parts; the citation of any document does not constitute an admission that it is prior art with respect to the present invention. If any meaning or definition of a term in this document conflicts with any meaning or definition of the same term in a document incorporated by reference, the meaning or definition given to the term in this document shall prevail.

[0133] Although specific embodiments of the invention have been illustrated and described, it will be apparent to those skilled in the art that various other changes and modifications can be made without departing from the spirit and scope of the disclosure. Accordingly, all such changes and modifications are intended to be covered by the appended claims which fall within the scope of the invention.

Claims

1. A device for heating molten long-chain hydrocarbons, comprising: - A heating section (1), the heating section having at least one material flow tube (101, 101a) extending from a heating section inlet (102) to a heating section outlet (103), the material flow tube (101, 101a) providing a flow path for the molten long-chain hydrocarbons from the heating section inlet (102) to the heating section outlet (103), and a heating structure (111, 112, 113) extending along at least a portion of the material flow tube (101, 101a), the heating structure (111, 112, 113) being configured to transfer heat to the material flow tube; and A separation volume (120, 220) downstream of the material flow tube (101, 101a), the separation volume being configured to allow hydrocarbon bubbles in the gas phase to separate from and rise above the hydrocarbons in the liquid phase, such that the hydrocarbons in the liquid phase occupy the lower portion of the separation volume (120, 220), while the hydrocarbons in the gas phase occupy the upper portion of the separation volume (120, 220), wherein the device is configured to keep the hydrocarbons in the gas phase separated from the hydrocarbons in the liquid phase.

2. The device according to claim 1, wherein the heating section (1) is a first heating section (1), the at least one material flow tube (101, 101a) is a first material flow tube (101, 101a), the heating section inlet (102) is a first heating section inlet (102), the heating section outlet (103) is a first heating section outlet (103), and the heating structure (111, 112, 113) is a first heating structure (111, 112, 113); and further comprising: - A second heating section (2), the second heating section having at least one second material flow tube (202) and at least one third material flow tube (203), the at least one second material flow tube (202) extending from a second heating section inlet (212) to a second heating section outlet (213), the at least one third material flow tube (203) extending from a third heating section inlet (222) to a third heating section outlet (223), the second material flow tube and the third material flow tube (202, 203) respectively providing a flow path for the molten long-chain hydrocarbons from the second heating section inlet and the third heating section inlet (212, 222) to the second heating section outlet and the third heating section outlet (213, 223), wherein the second heating section inlet and the third heating section inlet (212, 222) are configured to receive the molten long-chain hydrocarbons from the separation volume (120, 220) and split the flow path of the molten long-chain hydrocarbons to the at least one second material flow tube (202) and the at least one third material flow tube (203); and wherein the second heating section inlet (212) and the third heating section inlet (222) are arranged at different heights.

3. The device according to claim 1 or 2, wherein the flow paths of the molten long-chain hydrocarbon in the second material flow pipe and the third material flow pipe merge near the outlet of the second heating section and the outlet of the third heating section.

4. The device according to any one of the preceding claims, wherein the first heating section has at least two material flow pipes, which separate the flow path of the molten long-chain hydrocarbon near the inlet of the first heating section and merge the flow path of the molten long-chain hydrocarbon near the outlet of the first heating section.

5. The device according to any one of the preceding claims, wherein the second heating section has at least two second material flow pipes and / or at least two third material flow pipes.

6. The device according to any one of the preceding claims, wherein the top of the first heating section is at the same level as the bottom of the second heating section.

7. The device according to any one of the preceding claims, wherein the first heating section and / or the second heating section are configured to crack and separate the molten long-chain hydrocarbon into hydrocarbons in the gas phase and long-chain hydrocarbons in the liquid phase.

8. The device according to claim 7, further comprising a connection portion between the first heating section and the second heating section, wherein the connection portion forms a flow path for the molten long-chain hydrocarbon from the first heating section to the second heating section, and wherein the device is configured to maintain the separation of the hydrocarbons in the gas phase and the long-chain hydrocarbons in the liquid phase when passing through the connection portion.

9. The device according to claim 8, wherein the connection portion is configured such that the flow path extends substantially horizontally or at an angle of 0° to 45° with respect to the horizontal plane, preferably at an angle of 0° to 10° with respect to the horizontal plane, and the downstream end of the flow path is higher than the upstream end.

10. The device according to claim 8 or 9, wherein the connection portion and / or the mass flow rate are adjusted to maintain the separation of the hydrocarbons in the gas phase and the long-chain hydrocarbons in the liquid phase, wherein the flow pattern of the hydrocarbons in the gas phase and the long-chain hydrocarbons in the liquid phase inside the connection portion is preferably one of bubble, plug, stratified, wavy or slug patterns.

11. The device according to any one of claims 8 to 10, wherein the connection portion provides a single fluid channel having a circular cross-section.

12. The device according to any one of claims 8 to 11, wherein the device is configured to provide a temperature between 250 °C and 450 °C, a mass flow rate between 1000 kg / h and 20000 kg / h, a gas content of the hydrocarbons in the gas phase of 1 mass% to 50 mass%, a pressure between 100 kPa and 8100 kPa relative to the ambient air pressure, and a connection portion having a circular cross-section with an inner diameter of at least 50 mm at the connection portion.

13. The device according to any one of the preceding claims, wherein for the solid material suspended in the molten long-chain hydrocarbon, at least one of the first material flow pipe, the second material flow pipe, or the third material flow pipe provides an inner cross-section adapted to allow the solid material of a predetermined maximum size to pass through.

14. The device according to any one of claims 8 to 12, wherein the connecting portion is provided with an upper connecting pipe and a lower connecting pipe; The upper connecting pipe is arranged to allow the hydrocarbon in the gas phase to pass through, The lower connecting pipe is arranged to allow the long-chain hydrocarbon in the liquid phase to pass through.

15. The device according to any one of the preceding claims, further comprising at least one third heating section, each of the at least one third heating section having at least two fourth material flow pipes, each of the fourth material flow pipes extending from a respective fourth heating section inlet to a respective fourth heating section outlet, wherein the flow path diverges between the at least two fourth material flow pipes adjacent the fourth heating section inlet and converges adjacent the fourth heating section outlet, wherein each of the first heating section, the second heating section, and the at least one third heating section is configured such that the material containing the long-chain hydrocarbon continuously flows through each of them, and wherein at least one of the fourth material flow pipes preferably provides an inner cross-section adapted to allow the solid material of a predetermined maximum size to pass through.

16. The device according to any one of the preceding claims, further comprising a separation structure configured to receive the hydrocarbon in the liquid phase.

17. The device according to claim 16, further comprising a gas release pipe (53) configured to receive the hydrocarbon in the gas phase at the disengaging volume (120, 220, 320) and to convey the hydrocarbon in the gas phase; wherein the separation structure is configured to receive the hydrocarbon in the gas phase at an upper portion of the separation structure and to receive the hydrocarbon in the liquid phase at a lower portion of the separation structure.

18. The device according to any one of the preceding claims, wherein at least one of the heating sections is configured such that the flow path from the heating section inlet (102) to the heating section outlet (103) extends at an angle of 0° to 45° with respect to the horizontal plane, preferably at an angle of 0° to 10° with respect to the horizontal plane, and the downstream end of the flow path is higher than the upstream end.

19. The device according to any one of the preceding claims, wherein at least one of the heating sections is configured such that its respective heating section inlet (102) is lower than the heating section outlet (103).

20. A method for heating a plastic material to a pyrolysis temperature, the method comprising the following steps: - In a first heating zone, heating a body of material containing molten plastic to provide at least a first liquid phase and at least a first gas phase, the first liquid phase being mixed with the first gas phase in the first heating zone; - Separating the first liquid phase from the first gas phase to provide a body of material mainly of the first gas phase material and a body of material mainly of the first liquid phase material; - Transfer the first liquid-phase material and optionally the first gas-phase material to a second heating zone at a temperature higher than the first heating zone, and heat to provide at least a second liquid phase and at least a second gas phase, and mix the second liquid phase with the second gas phase; - Separate the second liquid phase from the second gas phase to provide a body mainly of the second gas-phase material and a body mainly of the second liquid-phase material; - Optionally repeat the steps of heating, gas formation, and gas separation one or more times in one or more additional heating zones, with the temperature of each subsequent heating zone increasing; and - Transfer the output liquid phase of the heating zone at the pyrolysis temperature to a pyrolysis reactor and / or a distillation device.

21. The method according to claim 20, wherein the first heating zone, the second heating zone, and the subsequent heating zones are heat exchangers, preferably shell-and-tube heat exchangers.

22. The method according to claim 21, wherein the first heating zone, the second heating zone, and the subsequent heating zones are different heat exchangers from each other.

23. The method according to any one of claims 20 to 22, wherein the body of the molten plastic, gas, and / or liquid flows through the heating zone when heated in the heating zone.

24. The method according to any one of claims 20 to 23, wherein the separation of the mixed liquid phase and gas phase mainly occurs downstream of each of the heating zones.

25. The method according to any one of claims 20 to 24, wherein the separation of the mixed liquid phase and gas phase occurs under gravity, and the gas phase rises out of the liquid phase.

26. The method according to any one of claims 20 to 25, wherein the plastic material is heated to a pyrolysis temperature of about 360 °C to about 550 °C, preferably about 390 °C to about 450 °C, before being injected into the separation container.

27. The method according to any one of claims 20 to 26, wherein the subsequent heating zones are arranged in series, and there is a phase separation volume between at least one or more of the subsequent heating zones.

28. The method according to any one of claims 20 to 27, wherein a plurality of the heating zones are arranged in series, and at least one or more of the downstream heating zones are located higher than the upstream heating zones.

29. The method according to any one of claims 20 to 28, wherein there is a final heating zone before the pyrolysis reactor, and the temperature of the liquid phase leaving the final heating zone is about 360 °C to about 550 °C, preferably about 390 °C to about 450 °C.

30. The method according to any one of claims 20 to 29, wherein the first heating zone is supplied with a material containing molten plastic by an extruder.

31. The method according to any one of claims 20 to 30, wherein the material containing molten plastic includes polyethylene and / or polypropylene plastic, preferably wherein the sum of polyethylene and polypropylene in the raw material is at least 50% by weight, more preferably at least 60% by weight, based on the weight of the raw material.

32. The method according to any one of claims 20 to 31, wherein the material containing molten plastic comprises polyvinyl chloride plastic, preferably greater than 1% by weight, more preferably greater than 5% by weight of polyvinyl chloride plastic, or wherein the raw material comprises less than 5% by weight, more preferably less than 1% by weight of polyvinyl chloride plastic.

33. The method according to any one of claims 20 to 32, wherein the material containing molten plastic comprises polyethylene terephthalate plastic, preferably greater than 3% by weight, more preferably greater than 4% by weight of polyethylene terephthalate plastic, or wherein the raw material comprises less than 4% by weight, more preferably less than 3% by weight of polyethylene terephthalate plastic.

34. The method according to any one of claims 20 to 33, wherein the material containing molten plastic comprises polystyrene plastic, preferably greater than 1% by weight, more preferably greater than 5% by weight of polystyrene plastic, or wherein the raw material comprises less than 20% by weight, more preferably less than 5% by weight of polystyrene plastic.

35. A method for producing hydrocarbon materials, which comprises the steps according to any one of the preceding claims 20 to 34, and a further step of distilling gaseous hydrocarbons in a distillation apparatus to obtain hydrocarbon products, preferably wherein the hydrocarbon products include butane, propane, kerosene, diesel oil, fuel oil; light distillates such as LPG, gasoline, naphtha or mixtures thereof; middle distillates such as kerosene, jet fuel, diesel oil or mixtures thereof; heavy distillates and residues such as fuel oil, lubricating oil, paraffin wax, wax, asphalt or mixtures thereof; or any mixtures thereof; saturated, unsaturated, straight-chain, cyclic or aromatic hydrocarbons; non-condensable gases including methane, ethane, ethylene and / or other small molecules; and mixtures thereof.

36. An apparatus for pyrolyzing waste plastics into one or more hydrocarbon products, preferably at least one or more liquid hydrocarbon products, the apparatus comprising: The apparatus according to any one of claims 1 to 19 and at least one pyrolysis zone downstream thereof, and at least one distillation apparatus for distilling pyrolyzed materials to obtain hydrocarbon products, preferably wherein the hydrocarbon products include butane, propane, kerosene, diesel oil, fuel oil; light distillates such as LPG, gasoline, naphtha or mixtures thereof; middle distillates such as kerosene, jet fuel, diesel oil or mixtures thereof; heavy distillates and residues such as fuel oil, lubricating oil, paraffin wax, wax, asphalt or mixtures thereof; or any mixtures thereof; saturated, unsaturated, straight-chain, cyclic or aromatic hydrocarbons; non-condensable gases including methane, ethane, ethylene and / or other small molecules; and mixtures thereof.

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