Plastic Pyrolysis Reactor

Abstract

A system for converting waste plastic materials into petrochemical products, the system including a feed inlet and distributor zone, a rake film reaction section located below the feed inlet and distributor zone, and a stirred tank reaction section located below the rake film reaction section.

Description

[Technical field]

[0001] SUMMARY OF THE DISCLOSURE Embodiments of the present disclosure generally relate to reactors for converting waste plastics into petrochemicals. [Background technology]

[0002] There is a rapid and growing environmental concern about the need to collect and recycle plastic waste.

[0003] Pyrolysis refers to the dissociation or decomposition of compounds by heat, and is specifically a process described in which long molecules are converted into liquid fuels by pyrolysis (cracking) in the absence of oxygen. During pyrolysis of plastic waste, for example, the plastic waste is first melted in a chamber, typically under an inert environment. The molten material is then heated and reacted to form lighter molecules, some of which may be in a gaseous state.

[0004] Pyrolysis of plastics is often done in a batch process where the batch reaches a single set point temperature or is provided at a constant heat input rate until the batch reaction is complete. Other processes step the feed through a series of heated zones, also using defined set temperatures and residence times for each zone.

[0005] For example, US 7,883,605 describes a process for pyrolyzing hydrocarbon materials, whereby thermal rates are defined based on reactor loadings in the range of 0.25 to 27 kW / kg.

[0006] In a semi-batch process, US10421911 (Alterra) describes an extruder section (having at least three zones) and a multi-zone kiln reactor (having at least two zones) including zones for (further) destabilization and dehalogenation, as well as zones for pyrolysis and devolatilization of the pyrolyzed hydrocarbon material.

[0007] After pyrolysis, the hot pyrolysis gases are then condensed in one or more condensers to produce a hydrocarbon distillate containing straight and branched chain fatty acids, cyclic fatty acids, and aromatic hydrocarbons. Traditionally, the resulting mixture is roughly equivalent to conventional diesel fuel after the implementation of additives and other minor downstream processing actions.

[0008] Typically, pyrolysis systems use two pyrolysis chambers that work together at approximately equal rates. A particular problem with existing pyrolysis chamber setups is that fuel can only be produced on a batch-type basis. Once both chambers have completed pyrolysis of waste in unison, it is necessary to wait for each to cool before the unwanted carbonaceous charcoal can be removed from inside each chamber. Thus, currently, it is necessary to wait for each chamber to cool and for the charcoal to be hand washed before the chamber can be used again for a second and subsequent batches.

[0009] Horizontal or slightly inclined screw conveyors have been used before for transporting and heating / cooling solid raw materials. For example, US Patent No. 9,321,964, US Patent No. 1,073,1081, US Patent No. 8,728,282, and US Patent Application Publication No. 2018 / 0355,256 disclose different types of horizontal or slightly inclined screw conveyor or kiln-type systems. These systems primarily use a rotor as a conveying device to move the material through the kiln. These references also have various steam recovery systems, but with the common feature that steam is continuously recovered from the kiln along its length or at the kiln outlet.

[0010] In addition to using screw conveyors to move materials through the kiln, other references disclose batch or semi-batch processes using stirred tank reactors (STRs). For example, US 10,131,847, US 10,208,253, and US 9,920,255 describe batch or semi-batch systems using STRs for the pyrolysis of plastic waste. US 9,920,255 notes that heat transfer in the stirred tank is limited by the low thermal conductivity and high viscosity of the molten plastic. To overcome this limitation, it has been necessary to dilute the plastic melt with large amounts (>50%) of heavy oil from fossil sources.

[0011] Further problems with existing pyrolysis systems include more frequent cleaning times of the chamber, poor heat transfer within the waste feedstock itself increasing process time per load, and also the cost and fouling of consumable catalysts. A final problem is the quality of the final fuel product, which includes a measure of the ability of diesel fuel to reduce wear on solid surfaces it contacts, such as those found in some fuel pumps and injectors. Summary of the Invention [Problem to be solved by the invention]

[0012] In view of the above, it is an object of the present invention to provide a pyrolysis reactor that uses waste plastic feedstock and has increased throughput of hydrocarbons of consistent quality. [Means for solving the problem]

[0013] Summary of the Invention One or more embodiments disclosed herein relate to a system for converting waste plastic materials into petrochemical products, the system including a feed inlet and distributor zone, a rake film reaction section located below the feed inlet and distributor zone, and a stirred tank reaction section located below the rake film reaction section.

[0014] Another embodiment disclosed herein relates to a system for converting waste plastic materials into petrochemicals. The system includes a feed inlet and distributor zone, and a stirred tank reaction section located below the feed inlet and distributor zone. [Brief description of the drawings]

[0015] [Figure 1] 1 illustrates a reactor design for a system according to one or more embodiments disclosed herein. [Diagram 2] 1 illustrates a reactor design for a system according to one or more embodiments disclosed herein. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] Embodiments herein are directed to one or more pyrolysis reactor designs for a thermochemical process for converting waste plastics into useful petrochemicals and other intermediate or end products.

[0017] The embodiments herein relate to a pyrolysis reactor that can convert waste plastics into useful oil, gas, and pitch. The oil can be used to produce fuel, blend with fuel, or to produce other hydrocarbon products. The reactor can be a modular system that includes melting processing (using a primary melting tank and extruder) to preheat the solid mixed plastic waste and remove contaminants such as chlorides, as well as a post-reaction separation system to separate the reactor effluent into useful product streams. The reactor can have a high throughput and can be operated in a continuous mode thanks to the high heat transfer rate that provides most of the conversion of plastics to pyrolysis products. Residual management is facilitated by using a stirred tank reactor (STR) section for further conversion, potentially producing additional useful products that can be used as additives to asphalt in some embodiments.

[0018] Generally, a vertically oriented, heated, jacketed pressure vessel reactor may be used in one or more embodiments. Heating sources include flue gas heating, electrical heating, or a combination of flue gas and electrical heating. This type of reactor may utilize an internal axially oriented rotating assembly to function as both a feed distributor and a film rake device. The feed may be diverted to form a film on the inside walls of the vessel, where the rotating rake stirs the film and sets its average speed of movement, or, again, controls the average residence time of the fluid in the reactor, thereby increasing heat transfer and maintaining the cleanliness of the heated surface. The vapors and gases exit the film toward the center of the vessel, where they rise and exit the top of the vessel. A liquid level is maintained at the bottom of the vessel to complete the conversion to vapor / gas, and the liquid pitch may be collected and extracted from the bottom, producing a heavy residue product. The vapors and gases produced may be sent to a distillation process for separation into one or more product streams.

[0019] In contrast to previous designs, one or more embodiments disclosed herein may use a rotating rake device to mix the fluids as they flow vertically down along the heated inner surface of the reactor vessel under gravity. The rake is close enough to the wall to continuously remove coke / ash deposits and wet the entire inner surface of the reactor vessel with molten plastic. The heat transfer resistance of a thin film of molten plastic may be exceptionally low, especially compared to the bulk solid or liquid material in the prior art. The heat transfer resistance may be further reduced by the action of the rotor.

[0020] As the vapor products exit the top of the reactor in countercurrent flow to the falling molten plastic film, the vapors generated at the bottom of the reactor will exchange heat with the cooled molten plastic as it travels down the reactor. In effect, the rising vapors continuously heat the falling and regenerating plastic. The exchange of heat and mass of the vapors generated with the pyrolysis of the plastic creates an internal recycle that increases the amount of light oil produced compared to the gaseous products and heavy oil components alone of the prior art.

[0021] In contrast to batch-type systems, one or more disclosed embodiments use a rake film reactor (RFR) section with a lower temperature, such as about 420-490°C, and a short residence time, such as 2-10 minutes, followed by a STR section at a slightly higher temperature, such as about 440-490°C, and a longer residence time, such as 20-60 minutes. The RFR section rapidly preheats the reacting melt to pyrolysis temperatures and can convert 30-80% of the polymer to pyrolysis products. The remaining unreacted material is fed to the STR section along with any material recondensed and recycled from the gas phase. The material in the STR section can be converted more slowly.

[0022] In one or more embodiments, using either reactor type, a heating jacket may be used between the inner reactor wall and an outer cylindrical housing connected to one or more hot flue gas paths along the height of the STR. The outer housing may be divided into different zones to allow for tailoring the heat rate to each zone to suit different feed characteristics. In one or more embodiments, the heating jacket may use molten metal between the inner reactor wall and the outer cylindrical housing. The high heat capacity of the molten metal may ensure that the plastic film is heated uniformly and continuously within each zone.

[0023] Thus, one or more embodiments disclosed will be generally described with details of the reactor system set forth below. In one or more embodiments, the thermal pyrolysis reactor may be a generally vertically oriented jacketed pressure vessel. At the top, the molten plastic feed enters the reactor via a feed tube at a feed temperature and flow rate. The liquid feed flows vertically into a rotating distributor device that evenly distributes the liquid to form a 360 degree thin film on the inner side shell of the reactor vessel.

[0024] Gravity will cause the material flow to flow over the side of the vessel. Heating jacket(s) on the outside of the pressure shell provide thermal energy for heating and reaction of the liquid feed. As the molten plastic flows down the wall, the viscosity decreases. The pyrolysis process forms a hard residue that forms on the wall and inhibits heat transfer if left unmitigated. A rotating rake assembly with elements that continuously stir / scoop the fluid on the inner surface rotates around the center of the reactor. The rotor shaft rotates both the upper distributor as well as an array of rake support arms. The rotor RPM is adjusted to control or set the average residence time (average vertical travel speed) of the fluid film flowing down the wall. The rake action can also increase heat transfer from the wall to the fluid.

[0025] The rake angle also reduces the buildup of thick or hard scaling on the walls, increasing the time between cleaning or maintenance cycles and maintaining consistent thermal performance.

[0026] The steam and gases produced by the reaction exit the reactor through ducts in the distributor assembly and from nozzles located at the top of the reactor vessel. As the steam travels upward, some of the steam may be recondensed and returned to the heated wall and mixed into the falling film. This internal reflux effect may increase the amount of product produced and reduce the amount of waste coal.

[0027] The bottom segment of the vertical pressure vessel reactor collects a liquid level of hot molten plastic / oil that has reacted almost completely. This liquid is a blend of heavy oil, plastic, ash, and other organic materials that have reacted and have not achieved volatilization and transition to gas / vapor phase. Heat is continuously added to the liquid by heat sources on the reactor walls and other surfaces on the bottom inverting head. A bottom agitator, such as an agitator with a close-in type impeller, may be used to keep the liquid in this section mixed at the walls to promote heat transfer while allowing the denser materials to drain under gravity. By controlling the heating and residence time of the reaction, the system may avoid the production of dry charcoal, which is a waste product.

[0028] A diagram of a reactor design according to an embodiment herein is shown in Figure 1. One or more feed inlet pipes 1 may introduce molten plastic feed material through the overhead vapor space in Zone A and deliver fresh molten plastic to a liquid level pool in distributor 2. Each inlet feed pipe 1 may also serve to disconnect entrained steam or gas from the upstream heating process so that it remains in the overhead vapor space without traversing within the body of the reactor.

[0029] The distributor 2 may take the form of any known distributor arrangement and may rotate with the rotor assembly or static. For example, the distributor 2 may be fixed to the rotating rotor assembly and equipped with a weir. The distributor 2 may hold the liquid at a high enough level so that the feed pipe 1 delivers the feed below the top level of the liquid so that the vapors and gases migrating up the reactor cannot enter the feed tube 1. As the distributor 2 rotates, the molten liquid plastic held by the weir may flow over the periphery and form a film of liquid plastic on the inner shell surface of the reactor shell 3. The overall diameter of the distributor 2 may be just smaller than the inner diameter of the reactor shell 3. Such a narrow diameter difference may allow for the formation of a uniform and continuous film layer on the inner wall of the reactor shell 3. In some embodiments, the distributor 2 equipped with a weir may include one or more notches (not shown) along the top or periphery of the weir to help control the flow of the molten liquid plastic onto the inner shell surface of the reactor shell 3. The distributor 2 may also include an opening in the center of the distributor 2 to direct steam and gas from the reaction space below to the overhead steam space without contacting the molten liquid plastic held in the distributor 2 by the weir. This configuration may allow for constant removal of generated steam from the system via the reactor outlet 20.

[0030] In the upper portion of the reactor vessel, including the feed tube 1, distributor 2 (Zones A and B, together referred to as the "feed inlet and distributor section"), the reactor shell is not actively heated by one or more heating jackets. Instead, Zones A and B may be insulated only to limit thermal energy losses. In the remaining Zones C, D, and E, the reactor shell 3 may function as a heat transfer surface to deliver the energy required to heat and convert the plastic feed to pyrolysis oil, steam, and gas. As referred to herein, Zones C and D may be referred to as the "rake film reaction section" and Zone E may be referred to as the "stirred tank reaction section."

[0031] Thus, zones C, D, and E are outside the vessel and may be equipped with a heat transfer jacket 4 attached to the outside of the reactor shell 3. The heat source may be divided into one or more heating zones, and the heat source may be a flue gas jacket, or an electric resistance heating source (electric heating element). A combination of an electric heating element and a flue gas jacket may also be used. In some embodiments, a first heating zone including a heating element and a second heating zone including a flue gas jacket may be used. In other embodiments, only the first heating zone or the second heating zone may be used. In the embodiment shown in FIG. 1, this heat transfer jacket 4 may be in thermal contact with one or more flue gas jackets 5 and may receive heat from one or more flue gas jackets 5. The heat transfer jacket 4 spreads the heat across the reactor shell 3. Zones C, D, and E may have one or more flue gas jackets 5. Each flue gas jacket 5 may provide a different level of heating load to each section. In such a scheme, a particular target temperature in each section can be achieved independently by heat transfer from a flowing gas phase heat source, such as waste heat from the flue gas, to the heat transfer jacket 4. A temperature gradient exists between the inlet and outlet of this annular space, and the heat transfer jacket 4 can spread that thermal energy such that the reactor shell 3 is less susceptible to this gradient and even heating within each zone can be achieved.

[0032] Each section of the flue gas jacket 5 may include a hot flue gas inlet 17 and a flue gas outlet 11. As the flue gas enters the hot flue gas inlet 17, it comes into contact with the exterior surface of the reactor shell 3. Heat is then transferred to the heat transfer jacket 4, providing heat to the reactor vessel interior, as previously described. Each of the hot gas jackets 5 may be supplied from the same or different flue gas sources, depending on the heat load required in each zone. In either embodiment, the amount of flue gas entering each flue gas jacket 5 may be controlled by opening or closing a valve (not shown) or adjusting the speed of a blower (not shown). By controlling the amount of flue gas entering a given flue gas jacket 5, the amount of heating in each zone C, D, and E can be controlled.

[0033] The flue gas in the flue gas jacket 5 may be from the combustion of natural gas, gas produced from the process, or both. Initially, the process may be started using natural gas. Natural gas may be fed to a burner for combustion. After some time, the non-condensable gas produced by the plastic pyrolysis process may be used as combustion gas. When sufficient supply is available, the flow of natural gas will be shut off and the produced gas will be fed to the burner to be burned and heat the system. The burner is supplied with air to complete the combustion reaction via a blower.

[0034] Although described above with respect to the use of a heat transfer jacket, embodiments herein additionally contemplate direct heating of the reactor's interior surface via a flue gas jacket, radiant energy from an electric heating element, or a combination thereof. For example, a reactor having a shell of sufficient thickness and electrical conductivity (heat capacity) can receive and evenly distribute heat from the flue gas or electric heating element to the molten polymer, eliminating the need for an intermediate heat transfer jacket. Thus, a reactor according to embodiments herein may include one or more heating zones located around the exterior surface of one or each of the rake film reaction section and the stirred tank reaction section. The one or more heating zones in such embodiments are configured to provide heat to the respective rake film reaction section or stirred tank reaction section, and the heat may be provided by an electric heating element, a flue gas jacket, or a combination thereof.

[0035] The interior sections of Zone C and Zone D may include a rake 6. The rake 6 may be fixed to a rotating rake arm 7 as part of a rotor assembly that rotates with the distributor 2 by the rotor shaft 8. The rake 6 may provide mechanical scraping of the flowing material on the inner wall of the reactor shell 3 to prevent the buildup of carbonized material on the reactor shell wall. In this way, the rotating rake 6 stirs the falling film or liquid material, allowing the heat transfer jacket 4 to provide a consistent heating surface. The rake should be very close to the wall or touching the wall. If the rake is touching the wall, the rake may include one or more springs to keep the rake in contact with the reactor shell 3 inner wall, or the rake itself may be fixed to the wall to act as a spring. The springs can maintain the rake or scraping action on the wall when there are slight variations in film thickness.

[0036] The reactor vessel may include a rotor shaft 8 and one or more rake arms 7 each having a rake angle disposed at a distal end of the rake arms that collectively constitute the rotational rake angle 6. The rotor shaft 8 is positioned on the central axis of the reactor vessel and oriented vertically. The rake arms 7 are fixed to the rotor shaft 8 to form a fixed structural member. The rake arms 7 may be fixed to the rotor shaft 8 via any known method, including but not limited to casting, welding, flanges, or bolts. Although shown with three rake arms 7, the rake 6 may be equipped with any number of rake arms 7 depending on the reactor design. Furthermore, the geometry of the rake arms 7 may be modified to follow the angle of the reactor vessel wall as well to provide a film of a particular thickness on the vessel wall. The distributor 2 may be fixed to the rotor shaft 8 such that as the rake 6 rotates, the distributor 2 rotates at the same speed.

[0037] The upper part of the rotor shaft 8 passes through a shaft seal and bearing assembly 21 and is coupled to a gearbox 22. The rotor shaft 8 receives drive torque from a rotor gearbox 22, which receives input from a rotor motor 23. The rotor motor 23 may be any known type of motor. In one or more embodiments, the rotor motor may be a variable frequency drive motor that can provide the rotational speed torque required for operation of the rake film section (Zones C and D) of the reactor, as well as torque feedback. The lower end of the rotor shaft 8 may be radially stabilized and supported by the agitator 10 via a rotor / agitator axial coupling 9.

[0038] The reactor vessel may also be equipped with an upper head body flange 19 located between Zone A and Zone B at an elevation adjacent to the distributor. When the rotor / axial coupling 9 is disengaged (uncoupled), the upper head body flange 19 may allow an overhead crane to lift the entire rotor assembly (including rotor motor 23, rotor gearbox 22, rotor shaft seal and bearing assembly 21, rotor shaft 8, rake arm 7, and rake 6) out of the reactor shell.

[0039] The rotor motor 23, through the rotor gearbox 22 and rotor shaft seal and bearing assembly 21, may provide a varied rake velocity, which may be controlled based on the amount of solid material being fed into the reactor vessel, the type of material, the amount of char buildup on the interior walls, and the amount of heating required. Additionally, by varying the rake velocity and the amount and geometry of the rake arms 7, the residence time of the material in zones C and D may be adjusted to achieve high conversion of the material.

[0040] The rotor / agitator axial coupling 9 may be rigidly fixed to either the rotor shaft 8 or the agitator 10, but not necessarily to both. By not being rigidly connected to both the rotor shaft 8 and the agitator 10, the rotor / agitator axial coupling 9 allows the rotor shaft 8 and the agitator 10 to operate at different rotational speeds, directions of rotation, or both.

[0041] In other embodiments, only a single motor and gearbox, such as rotor motor 23 and gearbox 22, may be provided. In such embodiments, the rotor shaft 8 may be coupled to both the rake arm 7 and the agitator 10. The gearbox and motor may thus be configured to provide a rotational torque to rotate the rake arm and the agitator at the same speed and in the same direction. The capital and operating costs for the additional motor and gearbox may be saved, but the ability to separately control the mixing time and residence time within the reaction zone may be sacrificed.

[0042] The agitator 10 interacts with the liquid volume present in Zone E, also referred to as the stirred tank section of the reactor. Agitation can help to keep the liquid from cooling and solidifying in the lower portion of the reactor vessel. Agitation can be provided by an agitator motor 14 and an agitator gearbox 15. The agitator motor 14 can be one of any known type of motor, such as a variable frequency drive motor, capable of providing the rotational speed and torque required for optimal operation of the agitator, as well as torque feedback.

[0043] The reactor vessel may also be equipped with a bottom head assembly 12. The diameter and height of the bottom heating assembly 12 may be optimized to control the ratio of available heating surface area to liquid volume zone E. In one or more embodiments, the heat source for the bottom head assembly may be flue gas (such as flue gas used in one or more flue gas jackets 5), a different circulating hot fluid, or an electric heating element. The entire bottom head assembly 12 may be a modular subsystem including the agitator 10, the agitator seal and bearing assembly 18, the agitator motor 14, and the agitator gearbox 15.

[0044] The bottom head assembly may include heating coils 13 and pitch auger 16. Heating coils 13 may provide any supplemental heat required for continued reaction in the liquid phase in Zone E. Separate heating coils 13 provide independent heating in the bottom head assembly 12, separate from heat sources in the flue gas jacket 5 in Zone E and the flue gas jackets 5 in Zones C and D.

[0045] Pitch forms in zones C, D, and E as debris, char, ash, and other residues that do not volatilize to gases or vapors during decomposition of the plastic feed material. The pitch auger 16 is configured to remove this pitch from the reactor by rotating to remove solid material from the bottom portion of the bottom head assembly. The speed at which the pitch auger 16 rotates defines how much pitch is removed and may be a function of the particular feedstock to the reactor vessel and the feedback torques of both the rotor gearbox 22 and the agitator gearbox 15. The recovered pitch may be a feedstock for further downstream processing. The pitch auger 16 may be supplemented with a pump (not shown) in some embodiments, or may be replaced by a pump in embodiments where a less viscous pitch is produced.

[0046] In one or more embodiments, the reactor vessel may have straight walls. In other embodiments, the reactor vessel may have tapered or sloping walls. As shown, the reactor vessel may have a sloping taper to the walls that forms a cone shape rather than a cylinder. The cone shape reduces the diameter of the reactor vessel from the top of the reactor to the bottom of the reactor. Straight or conical wall vessels may be selected to maintain a desired film thickness as the liquid is converted to vapor within the reactor vessel.

[0047] Turning now to FIG. 2, FIG. 2 illustrates a reactor design according to an embodiment herein.

[0048] In the embodiment of FIG. 2, one or more feed inlet pipes 101 may introduce molten plastic feed material through the overhead vapor space and deliver fresh molten plastic to the interior of the agitator drum 111. As the molten plastic lift auger 112 rotates, it scrapes molten plastic off the sides of the inner wall of the reactor shell 114, resulting in the molten plastic being mixed inside the reactor vessel. This configuration may allow for constant removal of generated steam from the system via the reactor outlet 115. An upper shaft seal and bearing 119 may provide support for both the auger 112 and may prevent generated gases from escaping the reactor except through the outlet 115.

[0049] The reactor shell 114 is outside the vessel and may be equipped with a heat transfer jacket 103 attached to the outside of the reactor shell 114. This heat transfer jacket 103 may be in thermal contact with one or more hot gas jackets 113 and may receive heat from one or more hot gas jackets 113. The heat transfer jacket 103 spreads the heat across the reactor shell 114. The flue gas jacket 113 may provide a heat load to the reactor by supplying flue gas to the hot flue gas inlet 110 and removing flue gas from the flue gas outlet 102. As the flue gas enters the hot flue gas inlet 110, the flue gas comes into contact with the exterior surface of the reactor shell 114. Heat is then transferred to the heat transfer jacket 103, as previously described, providing heat to the reactor vessel interior. In one or more embodiments, the amount of flue gas entering the flue gas jacket 113 may be controlled by opening and closing a valve (not shown). By controlling the amount of flue gas entering the flue gas jacket 113, the amount of heating within the reactor can be controlled.

[0050] As described, the agitator drum 111 may be equipped with an auger 112 that rotates around the central axis of the reactor. The auger is generally composed of an inclined surface that is spirally wrapped around a central shaft or pipe. As the auger 112 rotates, material is dragged in the direction of rotation either due to friction if the material is moving in a direction against gravity, or by mechanical forces of the included plane if the material is traversing in the opposite direction. As the auger 112 rotates, it may provide mechanical scraping of the flowing material on the reactor shell 114 inner wall to prevent the accumulation of charred material on the reactor shell wall. In this way, the auger agitates the falling film or liquid material, allowing the heat transfer jacket 103 to provide a consistent heating surface for melting the plastic material.

[0051] Additionally, hot gas, which may be the same as or different from the flue gas in the flue gas jacket 113, may be fed into the interior of the auger via flue gas inlet 117 and into the auger interior inlet 109. This hot gas will traverse the interior of the auger and exit the auger through hot gas outlet 116 on the agitator shaft slip ring 118. Because the auger may be a large piece of metal, molten plastic may tend to cool and solidify on the exterior surface of the auger. By heating the interior of the auger, this cooling effect can be reduced or eliminated.

[0052] The bottom of the auger 112 may be connected to a drum shaft 107. The drum shaft 107 passes through a lower shaft seal and bearing 108 and is coupled to a gearbox 105. The drum shaft 107 receives drive torque from a gearbox 105, which receives input from a motor 106. The motor 106 may be any known type of motor. In one or more embodiments, the motor may be a variable frequency drive motor that can provide the rotational speed torque required for operation of the auger, as well as torque feedback.

[0053] The motor 106, through the rotor gearbox 105 and the drum shaft 107, may provide a varied rotational speed, which may be controlled based on the amount of solid material being fed into the reactor vessel, the type of material, the amount of char buildup on the interior walls, and the amount of heating required. Additionally, by varying the rotational speed and geometry of the auger 112, the residence time of the material within the agitator drum 111 may be adjusted to achieve high conversion of the material.

[0054] As with the reactor of FIG. 1, the reactor vessel of FIG. 2 may be equipped with a pitch auger 104. The pitch auger 104 is configured to remove pitch from the reactor by rotating and removing solid material from the bottom portion of the bottom of the reactor. The speed at which the pitch auger 104 rotates defines how much pitch is removed and may be a function of both the particular feed to the reactor vessel and the feedback torque of the gearbox 105. The recovered pitch may be a feed for further downstream processing.

[0055] As discussed above, systems according to embodiments herein may be modular, provide high throughput due to high heating rates in the rake film section, facilitate continuous operation by converting molten plastic into a thin film on the heated surface, reduce the rate of char formation by reducing the skin temperature of the heated surface, flexibility to accommodate various types of mixed plastic waste by varying residence times and temperatures, and continuous scraping / cleaning of the inner reactor walls, thereby maintaining heat transfer surfaces and avoiding reactor shutdowns for cleaning.

[0056] Unless otherwise defined, all technical and scientific terms used have the same meaning as commonly understood by one of ordinary skill in the art to which these systems, devices, methods, processes, and compositions belong.

[0057] The singular forms "a," "an," and "the" include plural references unless the context clearly dictates otherwise.

[0058] As used in this specification and the appended claims, the terms "comprise," "has," and "include," and all grammatical variations thereof, are each intended to have an open, non-limiting meaning that does not exclude additional elements or steps.

[0059] "Optionally" means that the subsequently described event or circumstance may or may not occur. The description includes cases where the event or circumstance occurs and cases where it does not occur.

[0060] When the word "approximately" or "about" is used, the term can mean that there can be a variation in value of up to ±10%, up to 5%, up to 2%, up to 1%, up to 0.5%, up to 0.1%, or up to 0.01%.

[0061] Ranges may be expressed as from about one particular value to about another particular value, inclusive. When such a range is expressed, it is understood that another embodiment is from the one particular value to the other particular value, along with all particular values ​​and combinations thereof within that range.

[0062] While the present disclosure includes a limited number of embodiments, those skilled in the art having the benefit of this disclosure will appreciate that other embodiments may be devised that do not depart from the scope of the present disclosure, and therefore the scope should be limited only by the scope of the appended claims. What is claimed as new and desired to be protected by Letters Patent of the United States is:

Claims

1. 1. A system for converting waste plastic materials into petrochemical products, comprising: a feed inlet and distributor section; a rake film reaction section located below the feed inlet and distributor section; a stirred tank reaction section located below the rake film reaction section.

2. said feed inlet and distributor section comprising: one or more feed inlet pipes configured to receive a waste plastic material feed stream; a distributor assembly configured to collect molten plastic material within a weir and distribute the molten plastic material onto an interior wall of the rake film reaction section; 10. The system of claim 1, further comprising: a vapor outlet configured to collect and remove vapor effluent produced in the rake film reaction section.

3. The system comprises: one or more heating zones located around an exterior surface of each of the rake film reaction section and the stirred tank reaction section, the one or more heating zones being configured to provide heat to the rake film reaction section and the stirred tank reaction section; The system of claim 2 , wherein the one or more heating zones comprise an electric heating element, a flue gas jacket, or a combination thereof.

4. The rake film reaction section comprises: a rotor shaft located along the central axis of the rake film reaction section; one or more rake arms coupled to the rotor shaft; one or more rake angles disposed at the ends of the one or more rake arms; one or more heating zones located around an outer surface of the rake film reaction section, the one or more heating zones configured to supply heat to the rake film reaction section; a thermal conduction jacket positioned between the one or more heating zones and the interior wall, the thermal conduction jacket configured to spread the heat evenly along the interior wall; The system of claim 2 , wherein the one or more rake angles are configured to skive the interior wall, thereby mixing the molten plastic material flowing down the interior wall.

5. 5. The system of claim 4, wherein the one or more rake arms further include one or more springs, the one or more springs configured to maintain the one or more rake arms in contact with the interior wall.

6. 6. The system of claim 4 or 5, wherein the one or more heating zones located around the exterior of the rake film reaction section comprise a flue gas jacket, an electric heating element, or a combination thereof.

7. the stirred tank reaction section comprises: an agitator located within the stirred tank reaction section configured to agitate the liquid effluent from the rake film reaction section; one or more heating zones located about an exterior surface of the stirred-tank reaction section, the one or more heating zones configured to provide heating to the stirred-tank reaction section, the one or more heating zones about the exterior surface of the stirred-tank reaction section comprising a flue gas jacket, an electric heating element, or a combination thereof; a heating coil located within the interior of the stirred-tank reaction section, the heating coil configured to independently heat the liquid effluent within the stirred-tank reaction section, separate from the one or more heating zones located about the exterior of the stirred-tank reaction section; 6. The system of claim 4 or 5, further comprising a pitch auger configured to remove pitch products produced in the stirred tank reaction section.

8. The system of claim 4 or 5, wherein the distributor assembly is coupled to the rotor shaft.

9. a rotor gearbox coupled to the rotor shaft, the rotor gearbox configured to provide rotational torque to the rotor shaft; 6. The system of claim 4 or 5, further comprising: a rotor motor coupled to the rotor gearbox, the rotor motor configured to provide a rotational input to the rotor gearbox.

10. an agitator gearbox coupled to the agitator, the agitator gearbox configured to provide rotational torque to the agitator; 8. The system of claim 7, further comprising: an agitator motor coupled to the agitator gearbox, the agitator motor configured to provide a rotational input to the agitator gearbox.

11. 8. The system of claim 7, further comprising a rotor / agitator axial coupling configured to removably couple the rotor shaft to the agitator, the system further comprising an upper head body flange located on an outer surface of the feed inlet and distributor zone, the upper head body flange configured to allow removal of the feed inlet and distributor zone and the rake film reaction section when the rotor / agitator axial coupling is released.

12. an agitator coupled to the rotor shaft, and the system a gearbox coupled to the rotor shaft, the gearbox configured to provide rotational torque to the rotor shaft and the agitator; The system of claim 4 , further comprising: a motor coupled to the gearbox, the motor configured to provide a rotational input to the gearbox.

13. 4. The system of claim 3, wherein each of the flue gas jackets includes a hot flue gas inlet and a flue gas outlet, each flue gas inlet configured to receive flue gases including combustion products of a portion of the steam effluent.

14. 1. A system for converting waste plastic materials into petrochemical products, comprising: a feed inlet and distributor section; a stirred tank reaction section located below the feed inlet and distributor section.

15. said feed inlet and distributor section comprising: one or more feed inlet pipes configured to receive a waste plastic material feed stream; a vapor outlet configured to collect and remove vapor effluent produced in the stirred-tank reaction section.

16. the stirred tank reaction section comprises: a rotating auger located along the central axis of the stirred tank reaction section; one or more heating elements positioned about an exterior surface of the stirred-tank reaction section, the one or more heating elements configured to provide heat to the stirred-tank reaction section; a thermally conductive jacket positioned between the one or more heating elements and an interior wall, the thermally conductive jacket configured to spread the heat evenly along the interior wall; The system of claim 15 , wherein the rotating auger is configured to scrape the interior wall, thereby mixing the molten plastic material flowing down the interior wall.

17. 17. The system of claim 16, wherein the one or more heating elements located about the exterior of the stirred-tank reaction section comprise a flue gas jacket, an electric heating element, or a combination thereof.

18. The system of claim 17 , wherein each flue gas jacket includes a hot flue gas inlet and a flue gas outlet.

19. the stirred tank reaction section comprises:

19. The system of any one of claims 16-18, further comprising a pitch outlet configured to remove pitch products produced in the stirred-tank reaction section.

20. a rotor gearbox coupled to the rotating auger, the rotor gearbox configured to provide rotational torque to the rotating auger; 19. The system of any one of claims 16 to 18, further comprising: a rotor motor coupled to the rotor gearbox, the rotor motor configured to provide a rotational input to the rotor gearbox.

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