WO2023178137A1

WO2023178137A1 - Chemical recycling process and system for melting and pyrolysis of solid waste plastic

Info

Publication number: WO2023178137A1
Application number: PCT/US2023/064377
Authority: WO
Inventors: Kenneth Wayne HAMPTON; Daryl Bitting; Xianchun Wu; David Eugene SLIVENSKY
Original assignee: Eastman Chemical Company
Priority date: 2022-03-17
Filing date: 2023-03-15
Publication date: 2023-09-21

Abstract

It has been discovered that use of a single reactor for melting waste plastics and pyrolyzing the melted waste plastics can lower the carbon footprint of a chemical recycling facility. More particularly, by melting and pyrolyzing in the same reactor vessel, one may mitigate the need for additional heat sources, thereby decreasing the potential need to combust additional fossil fuels for heating purposes. Consequently, by utilizing the plastic liquification and pyrolysis reactor described herein, one can lower the carbon footprint of the chemical recycling facility described herein.

Description

CHEMICAL RECYCLING PROCESS AND SYSTEM FOR MELTING AND PYROLYSIS OF

SOLID WASTE PLASTIC

BACKGROUND

[0001] Waste plastic pyrolysis plays a part in a variety of chemical recycling technologies. The pyrolysis of waste plastic produces heavy components (e.g., waxes, tar, and char), as well as recycle content pyrolysis oil (r-pyoil) and recycle content pyrolysis gas (r-pygas). When the pyrolysis facility is located near another processing facility, such as a cracker facility, it is desirable to send as much of the r-pyoil and r-pygas as possible to the downstream processing facility to be used as a feedstock in forming other recycle content products (e.g., olefins, paraffins, etc.).

[0002] However, when pyrolysis facilities are added to existing downstream facilities, such as a cracking facility, the carbon footprint of the resulting combined facilities is not typically optimized as the primary focus is on the production of specific recycle content products. Consequently, even though recycle content products are being produced by these combined facilities, the environmental impact of the combined facilities may not be optimized so as to avoid releasing more carbon dioxide into the environment than is necessary. Therefore, such combined facilities may exhibit one or more process deficiencies that negatively impact the resulting global warming potential of the combined facilities. Thus, processing schemes for waste plastic pyrolysis that provide a lower carbon footprint are needed.

SUMMARY

[0003] In one aspect, the present technology concerns a chemical recycling process. Generally, the process comprises: (a) introducing a solid waste plastic into a melting and pyrolysis reactor; (b) melting and pyrolyzing at least a portion of the solid waste plastic in the melting and pyrolysis reactor with heat from a common heat source to thereby produce a pyrolysis gas stream and a pyrolysis oil stream; and (c) combining at least a portion of the pyrolysis oil stream with the solid waste plastic either - (i) prior to the introducing in the melting and pyrolysis reactor, or (ii) within the melting and pyrolysis reactor at a location upstream of a last off-take of pyrolysis gas from the melting and pyrolysis reactor.

[0004] In one aspect, the present technology concerns a chemical recycling process. Generally, the process comprises: (a) introducing a solid waste plastic into a melting and pyrolysis reactor; (b) melting and pyrolyzing at least a portion of the solid waste plastic in the melting and pyrolysis reactor to thereby produce a pyrolysis gas stream and a pyrolysis oil stream, wherein the melting and pyrolysis reactor comprises an auger for transporting the solid waste plastic and/or a liquefied waste plastic through the melting and pyrolysis reactor; and (c) combining at least a portion of the pyrolysis oil stream with the solid waste plastic either (i) prior to the introducing in the melting and pyrolysis reactor, or (ii) within the melting and pyrolysis reactor at a location upstream of a last off-take of pyrolysis gas from the melting and pyrolysis reactor.

[0005] In one aspect, the present technology concerns a chemical recycling system. Generally, the system comprises: (a) a plastic feed mechanism for receiving and metering plastic particles; (b) a pyrolysis reactor having a plastic feed inlet for receiving the plastic particles from the feed mechanism, a gas outlet for discharging pyrolysis vapors, and a liquid outlet for discharging pyrolysis liquids; and (c) a heater for providing heat to the pyrolysis reactor. Generally, the pyrolysis reactor comprises at least two stages separated from one another by an upright weir and/or a vertical drop. Furthermore, each stage of the pyrolysis reactor includes an agitator for promoting mixing of the reaction medium and/or horizontal movement of the reaction medium through each stage of the pyrolysis reactor.

BRIEF DESCRIPTION OF THE DRAWINGS

[0006] FIG. 1 is a block flow diagram illustrating the main steps of a process and facility for chemically recycling waste plastic using the plastic liquification and pyrolysis reactor according to embodiments of the present technology; [0007] FIG. 2 is a depiction of the plastic liquification and pyrolysis reactor according to embodiments of the present technology;

[0008] FIG. 3 is a depiction of the plastic liquification and pyrolysis reactor according to embodiments of the present technology; and

[0009] FIG. 4 is a depiction of the plastic liquification and pyrolysis reactor according to embodiments of the present technology.

DETAILED DESCRIPTION

[0010] To optimize the carbon footprint of the chemical recycling facility described herein, we have discovered that the use of a single reactor for melting waste plastics and pyrolyzing the melted waste plastics can lower the carbon footprint of the chemical recycling facility. More particularly, we have discovered that melting and pyrolyzing in the same reactor unit may mitigate the need for additional heat sources, thereby decreasing the potential need to combust additional fossil fuels for heating purposes. Consequently, by utilizing the plastic liquification and pyrolysis reactor described herein, we can lower the carbon footprint of the combined facilities described herein.

[0011] As used herein, the “carbon footprint” refers to the amount of carbon dioxide and other carbon compounds emitted due to the consumption of fossil fuels within the facility. As discussed below in greater detail, the carbon footprint of the chemical recycling facility may be measured based on a life cycle assessment (LCA) and provided as a Global Warming Potential (GWP).

[0012] FIG. 1 depicts an exemplary chemical recycling facility 10 comprising a liquification and pyrolysis reactor 12 and a cracking facility comprising a cracker furnace 14, a quench system 16, a compression system 18, and a separator 20. As shown in FIG. 1 , the chemical recycling facility 10 may also contain a separator 22 for separating the pyrolysis vapors into a pyrolysis gas stream and a fuel gas stream and another separator 24 for separating the pyrolysis oil from the pyrolysis residue. As depicted in FIG. 1 , a waste plastic stream may be treated in the liquification and pyrolysis reactor 12 so as to produce various pyrolysis products that may be further utilized downstream. It should be understood that FIG. 1 depicts one exemplary embodiment of the present technology. Certain features depicted in FIG. 1 may be omitted and/or additional features described elsewhere herein may be added to the system depicted in FIG. 1 . The various process steps are described below in greater detail.

Overall Chemical Recycling Facility

[0013] Turning now to FIG. 1 , the main steps of a process for chemically recycling waste plastic in a chemical recycling facility 10 are shown.

Chemical recycling processes and facilities as described herein may be used to convert waste plastic to recycle content products or chemical intermediates used to form a variety of end use materials. As shown in FIG. 1 , the waste plastic fed to the chemical recycling facility /process can be mixed plastic waste (MPW), pre-sorted waste plastic, and/or pre-processed waste plastic. [0014] In an embodiment or in combination with any embodiment mentioned herein, the chemical recycling facility 10 may be a commercialscale facility capable of processing significant volumes of mixed plastic waste. As used herein, the term “commercial scale facility” refers to a facility having an average annual feed rate of at least 500 pounds per hour, averaged over one year.

[0015] In an embodiment or in combination with any embodiment mentioned herein, the chemical recycling facility 10 may comprise two or more facilities, such as a pyrolysis facility (e.g., the pyrolysis reactor and the separators before the cracking facility) and a cracking facility (e.g., the cracker furnace, the quench system, the compressor system, and the separator), that are co-located with one another. As used herein, the term “co-located” refers to facilities in which at least a portion of the process streams and/or supporting equipment or services are shared between the two facilities.

When two or more of the facilities are co-located, the facilities may meet at least one of the following criteria (i) through (v): (i) the facilities share at least one non-residential utility service; (ii) the facilities share at least one service group; (iii) the facilities are owned and/or operated by parties that share at least one property boundary; (iv) the facilities are connected by at least one conduit configured to carry at least one process material (e.g., solid, liquid and/or gas fed to, used by, or generated in a facility) from one facility to another; and (v) the facilities are within 40, within 35, within 30, within 20, within 15, within 12, within 10, within 8, within 5, within 2, or within 1 mile of one another, measured from their geographical center. At least one, at least two, at least three, at least four, or all of the above statements (i) through (v) may be true.

[0016] Regarding (i), examples of suitable utility services include, but are not limited to, steam systems (co-generation and distribution systems), cooling water systems, heat transfer fluid systems, plant or instrument air systems, nitrogen systems, hydrogen systems, non-residential electrical generation and distribution, including distribution above 8000V, non- residential wastewater/sewer systems, storage facilities, transport lines, flare systems, and combinations thereof.

[0017] Regarding (ii), examples of service groups and facilities include, but are not limited to, emergency services personnel (fire and/or medical), a third- party vendor, a state or local government oversight group, and combinations thereof. Government oversight groups can include, for example, regulatory or environmental agencies, as well as municipal and taxation agencies at the city, county, and state level.

[0018] Regarding (iii), the boundary may be, for example, a fence line, a property line, a gate, or common boundaries with at least one boundary of a third-party owned land or facility.

[0019] Regarding (iv), the conduit may be a fluid conduit that carries a gas, a liquid, a solid/liquid mixture (e.g., slurry), a solid/gas mixture (e.g., pneumatic conveyance), a solid/liquid/gas mixture, or a solid (e.g., belt conveyance). In some cases, two units may share one or more conduits selected from the above list.

[0020] T urning again to FIG. 1 , a stream of waste plastic, which can be mixed plastic waste (MPW), may be introduced into the chemical recycling facility 10 from a waste plastic source. As used herein, the terms “waste plastic” and “plastic waste” refer to used, scrap, and/or discarded plastic materials, such as plastic materials typically sent to a landfill. The waste plastic stream fed to the chemical recycling facility 10 may include unprocessed or partially processed waste plastic. As used herein, the term “unprocessed waste plastic” means waste plastic that has not be subjected to any automated or mechanized sorting, washing, or comminuting. Examples of unprocessed waste plastic include waste plastic collected from household curbside plastic recycling bins or shared community plastic recycling containers. Partially processed waste plastics may originate from, for example, municipal recycling facilities (MRFs) or reclaimers. In certain embodiments, the waste plastic may comprise at least one of post-industrial (or pre-consumer) plastic and/or post-consumer plastic.

[0021] In an embodiment or in combination with any embodiment mentioned herein, the mixed waste plastic (MPW) includes at least two distinct types of plastic.

[0022] In an embodiment or in combination with any embodiment mentioned herein, all or a portion of the MPW in the waste plastic stream can originate from a municipal recycling facility (MRF).

[0023] In an embodiment or in combination with any embodiment mentioned herein, all or a portion of the MPW in the waste plastic stream can originate from a reclaimer facility.

[0024] Examples of suitable waste plastics can include, but are not limited to, polyolefins (PO), aromatic and aliphatic polyesters, polyvinyl chloride (PVC), polystyrene, cellulose esters, polytetrafluoroethylene, acrylobutadienestyrene (ABS), cellulosics, epoxides, polyamides, phenolic resins, polyacetal, polycarbonates, polyphenylene-based alloys, poly(methyl methacrylate), styrene-containing polymers, polyurethane, vinyl-based polymers, styrene acrylonitrile, and urea-containing polymers and melamines. [0025] Examples of specific polyolefins may include linear low-density polyethylene (LLDPE), low density polyethylene (LDPE), polymethylpentene, polybutene-1 , high density polyethylene (HDPE), atactic polypropylene, isotactic polypropylene, syndiotactic polypropylene, crosslinked polyethylene, amorphous polyolefins, and the copolymers of any one of the aforementioned polyolefins.

[0026] Examples of polyesters can include those having repeating aromatic or cyclic units such as those containing a repeating terephthalate, isophthalate, or naphthalate units such as PET, modified PET, and PEN, or those containing repeating furanate repeating units. As used herein, “PET” or “polyethylene terephthalate” refers to a homopolymer of polyethylene terephthalate, or to a polyethylene terephthalate modified with one or more acid and/or glycol modifiers and/or containing residues or moieties of other than ethylene glycol and terephthalic acid, such as isophthalic acid, 1 ,4- cyclohexanedicarboxylic acid, diethylene glycol, 2,2,4,4-tetramethyl-1 ,3- cyclobutanediol (TMCD), cyclohexanedimethanol (CHDM), propylene glycol, isosorbide, 1 ,4-butanediol, 1 ,3-propane diol, and/or neopentyl glycol (NPG). [0027] In an embodiment or in combination with any embodiment mentioned herein, the waste plastic stream comprises at least 20, at least 25, at least 30, at least 35, at least 40, at least 45, at least 50, at least 55, at least 60, at least 65, at least 70, at least 75, at least 80, at least 85, at least 90, at least 95, or at least 99 weight percent of one or more polyolefins, based on the total weight of the stream. Alternatively, or in addition, the waste plastic stream comprises not more than 99.9, not more than 99, not more than 97, not more than 92, not more than 90, not more than 85, not more than 80, not more than 75, not more than 70, not more than 65, not more than 60, not more than 55, not more than 50, not more than 45, not more than 40, not more than 35, not more than 30, not more than 25, not more than 20, not more than 15, not more than 10, or not more than 5 weight percent of one or more polyolefins, based on the total weight of the stream.

[0028] In one embodiment or in combination with any of the mentioned embodiments, the waste plastic stream comprises not more than 20, not more than 15, not more than 12, not more than 10, not more than 8, not more than 6, not more than 5, not more than 4, not more than 3, not more than 2, or not more than 1 weight percent of polyesters, based on the total weight of the stream. [0029] In one embodiment or in combination with any of the mentioned embodiments, the waste plastic stream comprises not more than 20, not more than 15, not more than 12, not more than 10, not more than 8, not more than 6, not more than 5, not more than 4, not more than 3, not more than 2, or not more than 1 weight percent of biowaste materials, based on the total weight of the stream. As used herein, the term “biowaste” refers to material recovered from living organisms or of organic origin. Exemplary biowaste materials include, but are not limited to, cotton, wood, saw dust, food scraps, animals and animal parts, plants and plant parts, and manure.

[0030] In an embodiment or in combination with any embodiment mentioned herein, the waste plastic stream can include not more than 10, not more than 5, not more than 4, not more than 3, not more than 2, not more than 1 , not more than 0.75, or not more than 0.5 weight percent of polyvinyl chloride (PVC), based on the total weight of the stream.

[0031] The general configuration and operation of each of the facilities that may be present in the chemical recycling facility 10 shown in FIG. 1 will now be described in further detail below, beginning with the optional preprocessing facility of the waste plastic source.

Optional Plastic Preprocessing

[0032] As shown in FIG. 1 , unprocessed, partially processed, and/or processed waste plastic, such as mixed plastic waste (MPW), may first be introduced into the chemical recycling facility 10 from a waste plastic source. The waste plastic source may include an optional preprocessing facility that can prepare the waste plastic feedstock for the downstream recycling processes. While in the optional preprocessing facility, the waste plastic feedstock may undergo one or more preprocessing steps to prepare it for chemical recycling. As used herein, the term “preprocessing facility” refers to a facility that includes all equipment, lines, and controls necessary to carry out the preprocessing of waste plastic. Preprocessing facilities as described herein may employ any suitable method for carrying out the preparation of waste plastic for chemical recycling using one or more of following steps, which are described in further detail below. Alternatively, in certain embodiments, the waste plastic source does not contain a preprocessing facility and the waste plastic stream is not subjected to any preprocessing before any of the downstream chemical recycling steps described herein. [0033] In an embodiment or in combination with any embodiment mentioned herein, the preprocessing facility of the waste plastic source may include at least one separation step or zone. The separation step or zone may be configured to separate the waste plastic stream into two or more streams enriched in certain types of plastics. Such separation is particularly advantageous when the waste plastic fed to the chemical recycling facility is MWP.

[0034] Any suitable type of separation device, system, or facility may be employed to separate the waste plastic into two or more streams enriched in certain types of plastics such as, for example, a PET-enriched stream and a PO-enriched stream. Examples of suitable types of separation include mechanical separation and density separation, which may include sink-float separation and/or centrifugal density separation. As used herein, the term “sink-float separation” refers to a density separation process where the separation of materials is primarily caused by floating or sinking in a selected liquid medium, while the term “centrifugal density separation” refers to a density separation process where the separation of materials is primarily caused by centrifugal forces.

[0035] Referring again to FIG. 1 , the waste plastic stream may be introduced into one or more downstream processing facilities (or undergo one or more downstream processing steps) within the chemical recycling facility 10. In an embodiment or in combination with any embodiment mentioned herein, at least a portion of the waste plastic stream may be directly or indirectly introduced into the plastic liquification and pyrolysis reactor 12, as shown in FIG. 1 . Generally, the waste plastic stream may be directly introduced into the plastic liquification and pyrolysis reactor 12 via a feed mechanism, such as a screw feeder, a hopper, a paddle feeder, a rotary airlock, a pneumatic conveyance system, a mechanic metal train or chain, or combinations thereof.

[0036] Additional details of each step, as well as the general integration of each of these steps or facilities with one or more of the others according to one or more embodiments of the present technology are discussed in further detail below.

The Plastic Liquification and Pyrolysis Reactor

[0037] As shown in FIG. 1 , the waste plastic stream may be introduced into a plastic liquification and pyrolysis reactor 12 in order to at least partially liquefy the waste plastics and pyrolyze the liquefied plastic stream.

[0038] Exemplary plastic liquification and pyrolysis reactors are depicted in FIGS. 2-4. Each of the exemplary plastic liquification and pyrolysis reactors depicted in FIGS. 2-4 are described in greater detail below. Furthermore, it should be noted that all of the relevant disclosure herein related to FIGS. 1-4, including the above and below disclosure regarding FIG. 1 , is applicable to each of the embodiments depicted in FIGS. 1 -4 unless otherwise noted. For example, any of the feedstock compositions, reaction conditions, and weight percentages disclosed in reference to each of FIGS. 1-4 may also be applicable to the embodiments depicted in the other figures, unless such disclosure would conflict with the embodiment depicted in that figure.

[0039] As shown in FIG. 2, the plastic liquification and pyrolysis reactor may comprise multiple reaction stages that are defined and separated by a vertical drop 38 and/or an upright weir 40. Furthermore, as shown in FIG. 2, each stage of the reactor may include an agitator 42 for promoting the mixture of the reaction mixture within each stage and/or the horizontal movement of the reaction medium through each subsequent stage of the reactor. Moreover, as shown in FIG. 2, the plastic liquification and pyrolysis reactor may comprise a plastic feed inlet for receiving the waste plastic stream from a plastic feed mechanism (not shown in FIG. 2), an optional feed inlet for the light pyrolysis oil stream, an outlet for the halogen-containing off-gas produced during the liquification and pyrolysis reactions, multiple outlets for the pyrolysis vapors 26 formed during each of the reaction stages, and a liquid outlet for the pyrolysis oil stream and pyrolysis residues.

[0040] In an embodiment or in combination with any embodiment mentioned herein, at least a portion of a pyrolysis oil stream from the plastic liquification and pyrolysis reactor can be combined with the waste plastic stream to form a liquified plastic in the first stage of the reactor. Generally, as shown in FIG. 2, all or a portion of the pyrolysis oil stream may be combined with the waste plastic stream prior to introduction into the reactor, or after the waste plastic stream enters the first stage of the reactor and within the first stage of the reactor. Although FIG. 2 depicts the pyrolysis oil stream as being introduced into the first stage of the reactor, the pyrolysis oil stream may be introduced at any point and stage within the reactor, as long as this introduction point is upstream of the last off-take (i.e. , outlet) of the pyrolysis vapors and/or pyrolysis gas from the reactor. This pyrolysis oil stream can be a “light pyrolysis oil stream,” which refers to a pyrolysis oil stream that has had at least a portion of the pyrolysis residue removed therefrom.

[0041] As shown in FIG. 2, the plastic liquification and pyrolysis reactor may comprise multiple reaction stages that are defined and separated by a vertical drop 38 and/or an upright weir 40. For example, the first reaction stage in FIG. 2 is separated from the other reaction stages via a vertical drop 38, while the remaining reaction stages are separated by upright weirs 40. Thus, the reactor depicted in FIG. 2 contains five different reaction stages. [0042] Although FIG. 2 depicts a plastic liquification and pyrolysis reactor as containing five different reaction stages, it is feasible that the plastic liquification and pyrolysis reactor may contain fewer or more reaction stages, if desired. In an embodiment or in combination with any embodiment mentioned herein, the plastic liquification and pyrolysis reactor may comprise at least 2, at least 3, at least 4, at least 5, at least 6, at least 7, at least 8, at least 9, or at least 10 distinct reaction stages, with each stage being separated by a vertical drop and/or upright weirs. Additionally, or in the alternative, the plastic liquification and pyrolysis reactor may comprise not more than 20, not more than 18, not more than 16, not more than 14, not more than 12, not more than 10, not more than 8, not more than 6, not more than 5, not more than 4, or not more than 3 distinct reaction stages, with each stage being separated by a vertical drop 38 and/or upright weirs 40. In certain embodiments, the plastic liquification and pyrolysis reactor may comprise 2 to 20, 2 to 16, 2 to 10, 3 to 16, 3 to 12, 3 to 8, 4 to 20, 4 to 12, 4 to 10, 5 to 20, 5 to 12, or 5 to 10 distinct reaction stages, with each stage being separated by a vertical drop 38 and/or upright weirs 40.

[0043] The weirs 40 used to separate and distinguish the reaction stages may be of identical or different heights. As shown in FIG. 2, the weirs 40 separating multiple reaction stages may sequentially decline in height so as to facilitate the flow of the reaction mixture to sequential reaction stages.

[0044] In an embodiment or in combination with any embodiment mentioned herein, the plastic liquification and pyrolysis reactor may comprise at least 2, at least 3, at least 4, at least 5, at least 6, at least 7, at least 8, at least 9, or at least 10 distinct reaction stages, with each stage being separated by a vertical drop. Additionally, or in the alternative, the plastic liquification and pyrolysis reactor may comprise not more than 20, not more than 18, not more than 16, not more than 14, not more than 12, not more than 10, not more than 8, not more than 6, not more than 5, not more than 4, or not more than 3 distinct reaction stages, with each stage being separated by a vertical drop. In certain embodiments, the plastic liquification and pyrolysis reactor may comprise 2 to 20, 2 to 16, 2 to 10, 3 to 16, 3 to 12, 3 to 8, 4 to 20, 4 to 12, 4 to 10, 5 to 20, 5 to 12, or 5 to 10 distinct reaction stages, with each stage being separated by a vertical drop. In such embodiments, the reaction stages separated by a vertical drop can be viewed as independent horizontal stages.

[0045] In an embodiment or in combination with any embodiment mentioned herein, the plastic liquification and pyrolysis reactor may comprise at least 2, at least 3, at least 4, at least 5, at least 6, at least 7, at least 8, at least 9, or at least 10 distinct reaction stages, with each stage being separated by upright weirs. Additionally, or in the alternative, the plastic liquification and pyrolysis reactor may comprise not more than 20, not more than 18, not more than 16, not more than 14, not more than 12, not more than 10, not more than 8, not more than 6, not more than 5, not more than 4, or not more than 3 distinct reaction stages, with each stage being separated by upright weirs. In certain embodiments, the plastic liquification and pyrolysis reactor may comprise 2 to 20, 2 to 16, 2 to 10, 3 to 16, 3 to 12, 3 to 8, 4 to 20, 4 to 12, 4 to 10, 5 to 20, 5 to 12, or 5 to 10 distinct reaction stages, with each stage being separated by upright weirs.

[0046] As noted above, each of the reaction stages may comprise at least one agitator 42 for facilitating the mixing and movement of the reaction mixture within the reactor stage. Generally, this agitator 42 can comprise an impeller, a paddle, or an auger system comprising one or more augers. As shown in FIG. 2, the first reaction stage has an auger system 44, while each of the subsequent four reaction stages utilize a continuous stirred impeller connected to a common axle. In an embodiment or in combination with any embodiment mentioned herein, each of the reaction stages within the reactor may comprise at least one agitator 42, such as an impeller, a paddle, or an auger system.

[0047] In an embodiment or in combination with any embodiment mentioned herein, when present, the auger systems 44 in each of the reaction stages may comprise at least 1 , at least 2, at least 3, or at least 4 augers. Additionally, or in the alternative, when present, the auger systems in each of the reaction stages may comprise not more than 10, not more than 9, not more than 8, not more than 7, not more than 6, not more than 5, not more than 4, or not more than 3 augers.

[0048] Due to the configurations of the reaction stages within the plastic liquification and pyrolysis reactor, the temperature may increase with each successive and sequential reaction stage. Thus, the first reaction stage may have the lowest reaction temperatures of any reaction stage, while the last reaction stage may have the highest reaction temperatures. In an embodiment or in combination with any embodiment mentioned herein, the temperature can increase in each successive reaction stage by at least 10°C, at least 20°C, at least 30°C, at least 40°C, at least 50°C, at least 60°C, at least 70°C, at least 80°C, at least 90°C, at least 100°C, at least 110°C, at least 110°C, at least 120°C, at least 130°C, at least 140°C, or at least 150°C. Additionally, or in the alternative, the temperature can increase in each successive stage by not more than 300°C, not more than 250°C, not more than 200°C, not more than 175°C, or not more than 150°C. In certain embodiments, the temperature can increase in each successive stage in the range of 10 to 300 °C, 10 to 150 °C, 30 to 300 °C, 30 to 175 °C, or 50 to 200 °C. It should be noted that these ranges can apply to reaction stages that are in direct sequential order (e.g., these ranges can apply to the temperature different between the first reaction stage and the second reaction stage) or these ranges may apply to reaction stages that are not directly in sequential order (e.g., these ranges can apply to the temperature difference between the first reaction stage and the fifth reaction stage). These temperature changes can be measured by measuring the temperature within the interior of each reaction stage and then comparing the temperatures.

[0049] Due to the increase in temperature in the successive reaction zones, there can be a distinct temperature variance in temperature between the waste plastic inlet of the reactor and the final outlet for the pyrolysis vapors. More particularly, in various embodiments, the temperature at the waste plastic inlet of the reactor may be at a lower temperature relative to the final outlet for the pyrolysis vapors in the reactor. In an embodiment or in combination with any embodiment mentioned herein, the temperature at the waste plastic inlet of the reactor may be at least 150, at least 200, at least 210, at least 220, at least 230, at least 240, at least 250, at least 260, at least

270, at least 280, at least 290, at least 300, at least 310, at least 320, at least

330, at least 340, at least 350, at least 360, at least 370, at least 380, at least

390, or at least 400 °C. Additionally, or in the alternative, the temperature at the waste plastic inlet of the reactor may be not more than 500, not more than

475, not more than 450, not more than 425, not more than 400, not more than

390, not more than 380, not more than 370, not more than 365, not more than

360, not more than 355, not more than 350, or not more than 345 °C. These temperatures may be measured by taking the temperature within the interior of the waste plastic inlet.

[0050] In an embodiment or in combination with any embodiment mentioned herein, the temperature at the final outlet of the pyrolysis vapors in the reactor may be at least 400, at least 450, at least 500, at least 525, at least 550, at least 575, at least 600, at least 625, at least 650, at least 675, at least 700, at least 725, at least 750, at least 775, or at least 800 °C. Additionally, or in the alternative, the temperature at the final outlet of the pyrolysis vapors in the reactor may be not more than 1 ,000, not more than 950, not more than 900, not more than 850, or not more than 800 °C. These temperatures may be measured by taking the temperature within the interior of the gas outlet.

[0051] In an embodiment or in combination with any embodiment mentioned herein, the interior space of the first reaction stage in the reactor, where the waste plastic is initially heated and liquefied (as discussed in greater detail below), may be maintained at a temperature of at least 200, at least 210, at least 220, at least 230, at least 240, at least 250, at least 260, at least 270, at least 280, at least 290, at least 300, at least 310, at least 320, at least 330, at least 340, at least 350, at least 360, at least 370, at least 380, at least 390, or at least 400 °C. Additionally, or in the alternative, the interior space of the first reaction stage in the reactor, where the waste plastic is initially heated and liquefied, may be maintained at a temperature of not more than 500, not more than 475, not more than 450, not more than 425, not more than 400, not more than 390, not more than 380, not more than 370, not more than 365, not more than 360, not more than 355, not more than 350, or not more than 345 °C. Generally, in one or more embodiments, the interior space of the first reaction stage in the reactor, where the waste plastic is initially heated and liquefied, may be maintained at a temperature ranging from 200 to 500 °C, 240 to 425 °C, 280 to 380 °C, or 320 to 350 °C.

[0052] In an embodiment or in combination with any embodiment mentioned herein, the interior space of any of the reaction stages downstream of the first reaction stage may be maintained at a temperature of at least 400, at least 450, at least 500, at least 525, at least 550, at least 575, at least 600, at least 625, at least 650, at least 675, at least 700, at least 725, at least 750, at least 775, or at least 800 °C. Additionally, or in the alternative, the interior space of any of the reaction stages downstream of the first reaction stage may be maintained at a temperature of not more than 1 ,000, not more than 950, not more than 900, not more than 850, or not more than 800 °C. Generally, in one or more embodiments, the interior space of any of the reaction stages downstream of the first reaction stage may be maintained at a temperature in the range of 400 to 1 ,000 °C, 500 to 900 °C, 550 to 850 °C, 625 to 850 °C, or 650 to 850 °C.

[0053] Furthermore, the reactor may have reaction “zones” that may be made up of two or more reaction stages that have similar reaction temperatures. As used herein, a “reaction zone” refers to an area within the plastic liquification and pyrolysis reactor made up of at least two reaction stages that exhibit a temperature within 50°C each other. For example, these reaction zones may be made from 2, 3, 4, 5, or 6 different reaction stages. In an embodiment or in combination with any embodiment mentioned herein, the temperatures within the reaction stages forming the reaction zones may consistently stay within 50°C, within 40°C, within 30°C, within 20°C, or within 15°C of each other. For instance, the bottom four reaction stages depicted in FIG. 2 (i.e. , those separated by the weirs 40) could be considered a single reaction zone if the temperatures within these four reaction stages do not deviate more than 50°C from each other.

[0054] The use of a convection box with the plastic liquification and pyrolysis reactor is optional, but such configurations may be used to better control temperatures within the reactor. The convection box may comprise thermal insulation in order to help retain the heat energy provided by the heating systems for the reactor. As used herein, the term “convection box” may refer to an enclosed structure of a furnace with at least one feed inlet for a heated gas to flow through, at least one outlet for the heated gas, and space to facilitate one or more vessels and/or heat exchange pathways. As depicted in FIG. 2, the plastic liquification and pyrolysis reactor is not positioned within a convection box.

[0055] Generally, the residence times of the feedstocks and reaction mixtures within each of the reaction stages can vary depending on the size of the reaction zone and the type of agitator that is present. In an embodiment or in combination with any embodiment mentioned herein, the residence times of the feedstocks and reaction mixtures within each reaction stage can be at least 0.1 , at least 0.2, at least 0.3, at least 0.5, at least 1 , at least 1 .2, at least 1 .3, at least 2, at least 3, or at least 4 seconds. Alternatively, the residence times of the feedstocks and reaction mixtures within each reaction stage can be at least 1 , at least 2, at least 3, at least 4, at least 5, at least 6, at least 7, at least 8, at least 9, at least 10, at least 20, at least 30, at least 45, at least 60, at least 75, or at least 90 minutes. Additionally, or alternatively, the residence times of the feedstocks and reaction mixtures within each reaction stage can be less than 6, less than 5, less than 4, less than 3, less than 2, less than 1 , or less than 0.5 hours. Furthermore, the residence times of the feedstocks and reaction mixtures within each reaction stage can be less than 1 ,000, less than 500, 100, less than 90, less than 80, less than 70, less than 60, less than 50, less than 40, less than 30, less than 20, less than 10, less than 9, less than 8, less than 7, less than 6, less than 5, less than 4, less than 3, less than 2, or less than 1 seconds. In certain embodiments, the residence times of the feedstocks and reaction mixtures within each reaction stage can range from 1 minute to 2 hours, 1 minute to 1 hour, or 1 minute to 0.5 hours.

[0056] In an embodiment or in combination with any embodiment mentioned herein, the residence times of the feedstocks and reaction mixtures within each reaction stage can decrease as the reaction mixtures progress through the reactor. Thus, in such embodiments, the residence times of the feedstocks and reaction mixtures within the reaction stages can decrease in successive and sequential reaction stages.

[0057] In an embodiment or in combination with any embodiment mentioned herein, the pressure within each of the reaction stages can be maintained at atmospheric pressure or within the range of 0.1 to 100 bar, or 0.1 to 60 bar, or 0.1 to 30 bar, or 0.1 to 10 bar, 0.2 to 1 .5 bar, or 0.3 to 1 .1 bar. As used herein, the term “bar” refers to gauge pressure, unless otherwise noted.

[0058] In the first stage of the plastic liquification and pyrolysis reactor of FIG. 2, the waste plastic stream may undergo liquification under agitation via an agitation device, such as an auger system. The auger system can promote the mixture of the reaction mixture within the first stage and facilitate the horizontal movement of the reaction medium, including the solid waste plastic and/or liquefied plastic, to the next reaction stage.

[0059] T urning back to FIG. 2, while in the first stage of the reactor depicted in FIG. 2, at least a portion of the waste plastics may undergo liquification so as to produce a liquefied plastic stream within the reactor. As used herein, the term “liquification” refers to a chemical processing zone or step in which at least a portion of the incoming plastic is liquefied. The step of liquefying plastic in the plastic liquification and pyrolysis reactor can include chemical liquification, physical liquification, or combinations thereof. Exemplary methods of liquefying the plastic introduced in the reactor can include: (i) heating/melting; (ii) dissolving in a solvent; (iii) depolymerizing; (iv) plasticizing; and combinations thereof. Additionally, one or more of options (i) through (iv) may also be accompanied by the addition of a blending or liquification agent with the waste plastic to help facilitate the liquification (reduction of viscosity) of the polymer material. As such, a variety of rheology modification agents (e.g., solvents, depolymerization agents, plasticizers, and blending agents) can be used the enhance the flow and/or dispersibility of the liquified waste plastic.

[0060] When added to the first reaction stage in the plastic liquification and pyrolysis reactor, at least 50, at least 55, at least 60, at least 65, at least 70, at least 75, at least 80, at least 85, at least 90, at least 95, or at least 99 weight percent of the plastic (usually waste plastic) originally present in the waste plastic stream undergoes a reduction in viscosity. In some cases, the reduction in viscosity can be facilitated by heating (e.g., addition of steam directly or indirectly contacting the plastic), while, in other cases, it can be facilitated by combining the plastic with a solvent capable of dissolving it. Examples of suitable solvents can include, but are not limited to, alcohols such as methanol or ethanol, glycols such as ethylene glycol, diethylene glycol, triethylene glycol, neopentyl glycol, cyclohexanedimethanol, glycerin, pyrolysis oil, motor oil, and water. This dissolution solvent can be added directly to the first reaction stage, or it can be previously combined with one or more streams fed to the first reaction stage, including the waste plastic stream.

[0061] In an embodiment or in combination with any embodiment mentioned herein, the dissolution solvent can comprise a stream withdrawn from one or more other facilities within the chemical recycling facility. For example, the solvent can comprise a stream withdrawn from the reactor. In certain embodiments, the dissolution solvent can be or comprise pyrolysis oil, such as light pyrolysis oil.

[0062] In some cases, the waste plastic can be depolymerized such that, for example, the number average chain length of the plastic is reduced by contact with a depolymerization agent. In an embodiment or in combination with any embodiment mentioned herein, at least one of the previously-listed solvents may be used as a depolymerization agent, while, in one or more other embodiments, the depolymerization agent can include an organic acid (e.g., acetic acid, citric acid, butyric acid, formic acid, lactic acid, oleic acid, oxalic, stearic acid, tartaric acid, and/or uric acid) or inorganic acid such as sulfuric acid (for polyolefins). The depolymerization agent may reduce the melting point and/or viscosity of the polymer by reducing its number average chain length.

[0063] Alternatively, or additionally, a plasticizer can be used in the first reaction stage to reduce the viscosity of the plastic. Plasticizers for polyethylene include, for example, dioctyl phthalate, dioctyl terephthalate, glyceryl tribenzoate, polyethylene glycol having molecular weight of up to 8,000 Daltons, sunflower oil, paraffin wax having molecular weight from 400 to 1 ,000 Daltons, paraffinic oil, mineral oil, glycerin, EPDM, and EVA.

Plasticizers for polypropylene include, for example, dioctyl sebacate, paraffinic oil, isooctyl tallate, plasticizing oil (Drakeol 34), naphthenic and aromatic processing oils, and glycerin. Plasticizers for polyesters include, for example, polyalkylene ethers (e.g., polyethylene glycol, polytetramethylene glycol, polypropylene glycol or their mixtures) having molecular weight in the range from 400 to 1500 Daltons, glyceryl monostearate, octyl epoxy soyate, epoxidized soybean oil, epoxy tallate, epoxidized linseed oil, polyhydroxyalkanoate, glycols (e.g., ethylene glycol, pentamethylene glycol, hexamethylene glycol, etc.), phthalates, terephthalates, trimellitate, and polyethylene glycol di-(2-ethylhexoate). When used, the plasticizer may be present in an amount of at least 0.1 , at least 0.5, at least 1 , at least 2, or at least 5 weight percent and/or not more than 10, not more than 8, not more than 5, not more than 3, not more than 2, or not more than 1 weight percent, based on the total weight of the waste plastic stream, or it can be in a range of from 0.1 to 10 weight percent, 0.5 to 8 weight percent, or 1 to 5 weight percent, based on the total weight of the waste plastic stream.

[0064] Further, one or more of the methods of liquefying the waste plastic stream can also include adding at least one blending agent to the plastic stream before, during, or after the first reaction stage in the reactor. Such blending agents may include for example, emulsifiers and/or surfactants, and may serve to more fully blend the liquified plastic into a single phase, particularly when differences in densities between the plastic components of a mixed plastic stream result in multiple liquid or semi-liquid phases. When used, the blending agent may be present in an amount of at least 0.1 , at least 0.5, at least 1 , at least 2, or at least 5 weight percent and/or not more than 10, not more than 8, not more than 5, not more than 3, not more than 2, or not more than 1 weight percent, based on the total weight of the waste plastic stream, or it can be in a range of from 0.1 to 10 weight percent, 0.5 to 8 weight percent, or 1 to 5 weight percent, based on the total weight of the waste plastic stream.

[0065] In an embodiment or in combination with any embodiment mentioned herein, the liquified (or reduced viscosity) plastic stream in the first reaction stage of the reactor can include at least 1 , at least 5, at least 10, at least 15, at least 20, at least 25, at least 30, at least 35, at least 40, at least 45, at least 50, at least 55, at least 60, at least 65, at least 70, at least 75, at least 80, at least 85, at least 90, at least 95, or at least 99 weight percent and/or not more than 95, not more than 90, not more than 85, not more than 80, not more than 75, not more than 70, not more than 65, not more than 60, not more than 55, not more than 50, not more than 45, not more than 40, not more than 35, not more than 30, not more than 25, not more than 20, not more than 15, not more than 10, not more than 5, not more than 2, or not more than 1 weight percent of one or more polyolefins, based on the total weight of the stream, or the amount of polyolefins can be in the range of from 1 to 99 weight percent, 5 to 90 weight percent, or 10 to 85 weight percent, based on the total weight of the stream.

[0066] In an embodiment or in combination with any embodiment mentioned herein, the liquified plastic stream exiting the first reaction stage of the reactor can have a viscosity of less than 3,000, less than 2,500, less than 2,000, less than 1 ,500, less than 1 ,000, less than 800, less than 750, less than 700, less than 650, less than 600, less than 550, less than 500, less than 450, less than 400, less than 350, less than 300, less than 250, less than 150, less than 100, less than 75, less than 50, less than 25, less than 10, less than 5, or less than 1 poise, as measured using a Brookfield R/S rheometer with a V80-40 vane spindle operating at a shear rate of 10 rad/s and a temperature of 350°C.

[0067] Generally, when the waste plastic is heated in the first reaction stage of the reactor, halogen-enriched waste gases can evolve. By disengaging the evolved halogen-enriched gasses from the liquified plastics, the concentration of halogens in the liquified plastic stream can be reduced. As shown in FIG. 2, at least a portion of the resulting halogen-containing offgas may be removed from the first reaction stage for further treatment in a halogen removal system to thereby form a halogen-depleted stream and a halogen-enriched stream. As shown in FIGS. 1 and 2, the halogen-containing off-gas may be removed upstream from any outlets that remove the pyrolysis vapors, which can include the pyrolysis gas. [0068] In an embodiment or in combination with any embodiment mentioned herein, the liquified plastic stream exiting the first reaction stage of the reactor can have a halogen content of less than 500, less than 400, less than 300, less than 200, less than 100, less than 50, less than 10, less than 5, less than 2, less than 1 , less than 0.5, or less than 0.1 ppmw.

[0069] In an embodiment or in combination with any embodiment mentioned herein, the liquefied waste plastic stream exiting the first reaction stage of the reactor may have a temperature of at least 200, at least 225, at least 250, at least 275, at least 300, at least 310, at least 320, at least 330, or at least 340 °C and/or less than 450, less than 425, less than 400, less than 375, or less than 350 °C.

[0070] While in the subsequent reaction stages after the first reaction stage of the reactor, and possibly within the first reaction stage if the temperature conditions are met, the reaction mixture comprising the remaining solid waste plastic and the liquefied plastic may be subjected to pyrolysis. As used herein, the term “pyrolysis” refers to thermal decomposition of a feedstock of a biomass and/or a plastic material in solid or liquid form at elevated temperatures in an inert (i.e., substantially molecular oxygen free) atmosphere. Pyrolysis is a process that involves the chemical and thermal decomposition of the introduced feed. Although all pyrolysis processes may be generally characterized by a reaction environment that is substantially free of oxygen, pyrolysis processes may be further defined, for example, by the pyrolysis reaction temperature within the reaction stage, the residence time within the reaction stage, the pressure within the reaction stage, and the presence or absence of pyrolysis catalysts.

[0071] While in the pyrolysis reactor, at least a portion of the feed may be subjected to a pyrolysis reaction that produces a pyrolysis effluent comprising a pyrolysis oil, a pyrolysis gas, and a pyrolysis residue. As depicted in FIGS. 1 and 2, the plastic liquification and pyrolysis reactor 12 may produce various streams of pyrolysis products, including one or more pyrolysis oil streams and one or more pyrolysis vapor streams. Generally, the pyrolysis vapors can comprise the pyrolysis gas and uncondensed pyrolysis oil. [0072] In an embodiment or in combination with any embodiment mentioned herein, a lift gas and/or a feed gas may be used to move the feedstock through the reaction stages within the pyrolysis reactor and/or facilitate various reactions within the reactor. For instance, the lift gas and/or the feed gas may comprise, consist essentially of, or consist of nitrogen, carbon dioxide, and/or steam. The lift gas and/or feed gas may be added with the waste plastic stream prior to introduction into the reactor and/or may be added directly to the reactor. The lift gas and/or feed gas can include steam and/or a reducing gas such as hydrogen, carbon monoxide, and combinations thereof.

[0073] In an embodiment or in combination with any embodiment mentioned herein, a pyrolysis catalyst may be introduced into the liquified plastic stream prior to introduction into the reactor and/or introduced directly into the reactor. The catalyst can be homogenous or heterogeneous and may include, for example, certain types of zeolites and other mesostructured catalysts. In some embodiments, the pyrolysis reaction may not be catalyzed (e.g., carried out in the absence of a pyrolysis catalyst), but may include a non-catalytic, heat-retaining inert additive, such as sand, in the reactor in order to facilitate the heat transfer. Such catalyst-free pyrolysis processes may be referred to as “thermal pyrolysis.”

[0074] In an embodiment or in combination with any embodiment mentioned herein, the liquification and pyrolysis reactor may be at least partially heated by a combustion system comprising a plurality a burners that combust a combustion fuel and a combustion air. The combustion fuel may comprise a conventional fossil fuel and/or a recycle content fuel, such as recycle content alkanes (e.g., r-methane) and/or recycle content hydrogen derived from the chemical recycling facility.

[0075] Due to the multiple reaction stages, the rise of sequential temperatures within the successive reaction stages, and the use of multiple outlets for removing pyrolysis vapors produced during the pyrolysis reactions from the reactor, the viscosity of the liquefied plastic stream can actually increase with each successive reaction stage, after the first reaction stage. Although not wishing to be bound by theory, it is believed that the solid waste plastic will initially liquefy in the first reaction stage, thereby reducing the viscosity of the feed stream. Thus, the reaction mixture, including the liquefied waste plastic and the remaining solid waste plastic, will have a lower viscosity relative to the initial feed stream into the reactor. However, successive reaction stages after the first reaction stage may occur under pyrolysis conditions, thereby producing pyrolysis vapors, including pyrolysis gas and pyrolysis oil, which may be removed via one or more outlets associated with the respective reaction stage. Consequently, this can leave a reaction mixture comprising a liquefied waste plastic that has a greater viscosity at the end the reaction stage relative to the beginning, which is due to the formation and removal of the lighter components from the reaction mixture via the outlets. Therefore, in an embodiment or in combination with any embodiment mentioned herein, after the first reaction stage, the viscosity of the liquefied plastic may increase with each sequential and successive reaction stage after the first reaction stage. For example, the liquefied plastic in the fourth reaction stage may have a higher viscosity relative to the liquefied plastic in the third reaction stage, which in turn may have a higher viscosity relative to the liquefied plastic in the second reaction stage.

[0076] As shown in FIGS. 1 and 2, at least a portion of the pyrolysis liquids 28 may be removed from the reactor via a liquid outlet. Generally, this pyrolysis liquid stream 28 may comprise pyrolysis oil, molten plastic, and various solids (when measured at 25°C at 1 atm), which may include unreacted plastic solids and pyrolysis residues.

[0077] Furthermore, as shown in FIGS. 1 and 2, after exiting the liquification and pyrolysis reactor, this pyrolysis liquid stream 28 from the liquid outlet may be separated in a separation system 24 into a light pyrolysis oil stream, a pyrolysis residue stream, and a pyrolysis vapor stream.

Although not depicted in FIGS. 1 and 2, this separation system 24 can include various types of equipment including, but not limited to a filter system, a multistage separator, a condensation zone, a distillation column, and/or a quench tower. While in the separation system 24, the pyrolysis liquid 28 from the reactor, which may include some vaporized pyrolysis oil, may be cooled to at least partially condense the vaporized pyrolysis oil fraction in the pyrolysis vapors.

[0078] As shown in FIGS. 1 and 2, at least a portion of the light pyrolysis oil stream 30 may be removed from the separator and introduced back upstream into the waste plastic feed stream or within one or more reaction stages of the reactor. As demonstrated in FIG. 2, a pump may be used to facilitate the movement of the light pyrolysis oil stream 30. Generally, at least 50, at least 60, at least 70, at least 75, at least 80, at least 85, at least 90, at least 95, or at least 99 percent of the light pyrolysis oil stream 30 formed in the melting and pyrolysis reactor may be reintroduced into the reactor. In certain embodiments, all of the light pyrolysis oil stream 30 from the separator is reintroduced back into the reactor.

[0079] As noted above, a “light pyrolysis oil” refers to a pyrolysis oil stream that has had at least a portion of the pyrolysis residue removed therefrom. In an embodiment or in combination with any embodiment mentioned herein, the light pyrolysis oil stream 30 may comprise less than 5, less than 4, less than 3, less than 2, less than 1 , less than 0.5, less than 0.1 , or less than 0.01 weight percent of pyrolysis residue, based on the total weight of the stream. [0080] The temperature of the light pyrolysis oil stream 30 can influence where the stream is introduced into the reactor. For instance, if the light pyrolysis oil stream 30 has a temperature of less than 325°C, then the stream may be combined with the waste plastic feed stream before introduction into the reactor and/or directly into the first reaction stage of the reactor (upstream from the halogen-containing off-gas outlet). Alternatively, if the light pyrolysis oil stream 30 has a temperature of greater than 325°C, the stream may be introduced into the second reaction stage or thereafter, depending on the temperatures of the reaction stages.

[0081] Furthermore, as shown in FIG. 1 , after exiting the liquification and pyrolysis reactor, at least a portion of the pyrolysis vapor streams 26 may be separated in a separator 22 to form a pyrolysis gas stream and a fuel gas stream. In certain embodiments, a pyrolysis oil stream may also be formed by this separator 22 if the pyrolysis vapors contain a significant enough fraction of pyrolysis oil. This residual pyrolysis oil stream may be further recycled back into the reactor in the same manner as the light pyrolysis oil stream 30. Although not depicted in FIG. 1 , this separation system 22 can include various types of equipment including, but not limited to a filter system, a multistage separator, a condensation zone, a distillation column, and/or a quench tower. [0082] FIG. 3 depicts another exemplary multi-staged liquification and pyrolysis reactor that may be used herein. It should be noted that all of the relevant disclosure from above regarding FIGS. 1 and 2 also applies to the embodiment depicted in FIG. 3, unless otherwise noted. Thus, all of the reaction conditions, reaction stage disclosure, and separation steps disclosed above in regard to FIGS. 1 and 2 would also be applicable to FIG. 3.

[0083] As shown in FIG. 3, the liquification and pyrolysis reactor has two reaction stages divided by a vertical drop 38. Furthermore, both reaction stages contain an auger system 44 for agitation purposes. The waste plastic and light pyrolysis oil stream 30 may be fed into the reactor via a hopper 46. [0084] In addition, at least a portion of the reactor in FIG. 3 is positioned in a convection box 48, so as to retain heat produced by the heating system, which is shown as a combustion device with multiple burners 50 in FIG. 3. As shown in FIG. 3, the combustion device is positioned within the convection box and the flue gas from the combustion device is allowed to vent from an outlet at the top of the convection box 48. Although FIG. 3 depicts only a portion of the reactor being positioned within the convection box, it is envisioned that the reactor may be entirely positioned within the convection box 48 in certain circumstances.

[0085] Moreover, in an embodiment or in combination with any embodiment mentioned herein, at least a portion of the fuel gas from the separator may be routed to the combustion device and used as the combustion fuel to provide heat for the reactor. Alternatively, at least a portion of the fuel gas may be removed from the facility and/or used in downstream chemical synthesis. As shown in FIG. 3, both reaction stages of the reactor may be heated by a common heat source (i.e. , the combustion device).

[0086] Furthermore, as shown in FIG. 3, at least a portion of the light pyrolysis oil stream 30 may be combined with the pyrolysis vapors in order to be subjected to further separation in the downstream separation system.

[0087] FIG. 4 depicts yet another exemplary multi-staged liquification and pyrolysis reactor that may be used herein. It should be noted that all of the relevant disclosure from above regarding FIGS. 1 -3 also applies to the embodiment depicted in FIG. 4, unless otherwise noted. Thus, all of the reaction conditions, reaction stage disclosure, and separation steps disclosed above in regard to FIGS. 1 -3 would also be applicable to FIG. 4.

[0088] The liquification and pyrolysis reactor depicted in FIG. 4 has the same reaction stage configuration as in FIG. 3. The key difference between the embodiments in FIGS. 3 and 4 is the incorporation of multiple heating systems within the convection box 48 in FIG. 4. Thus, in certain embodiments, each of the reaction stages may be heated by its own heating system 52. Exemplary heating systems 52 may include, for example, a combustion furnace, an electric heater, a heat transfer medium loop, or a combination thereof.

[0089] In an embodiment or in combination with any embodiment mentioned herein, the pyrolysis vapor streams from the liquification and pyrolysis reactors described herein may comprise at least 1 , at least 5, at least 10, at least 15, at least 20, at least 25, at least 30, at least 35, at least 40, at least 45, at least 50, at least 55, at least 60, at least 65, at least 70, or at least 75 weight percent of the pyrolysis oil, based on the total weight of the pyrolysis effluent or pyrolysis vapors. Additionally, or alternatively, the pyrolysis vapor streams may comprise not more than 99, not more than 95, not more than 90, not more than 85, not more than 80, not more than 75, not more than 70, not more than 65, not more than 60, not more than 55, not more than 50, not more than 45, not more than 40, not more than 35, not more than 30, or not more than 25 weight percent of the pyrolysis oil, based on the total weight of the stream. As discussed above, the pyrolysis oil may be in the form of uncondensed vapors in the pyrolysis effluent upon exiting the heated reactor; however, these vapors may be subsequently condensed into the resulting pyrolysis oil.

[0090] In an embodiment or in combination with any embodiment mentioned herein, the pyrolysis vapor stream from the liquification and pyrolysis reactors described herein may comprise at least 1 , at least 5, at least 10, at least 15, at least 20, at least 25, at least 30, at least 35, at least 40, at least 45, at least 50, at least 55, at least 60, at least 65, at least 70, at least 75, or at least 80 weight percent of the pyrolysis gas, based on the total weight of the stream. Additionally, or alternatively, the pyrolysis vapor streams may comprise not more than 99, not more than 95, not more than 90, not more than 85, not more than 80, not more than 75, not more than 70, not more than 65, not more than 60, not more than 55, not more than 50, or not more than 45 weight percent of the pyrolysis gas, based on the total weight of the stream.

[0091] The resulting pyrolysis oil stream and pyrolysis gas stream may be directly used in various downstream applications based on their formulations. The various characteristics and properties of the pyrolysis oil, pyrolysis gas, and pyrolysis residue are described below. It should be noted that, while all of the following characteristics and properties may be listed separately, it is envisioned that each of the following characteristics and/or properties of the pyrolysis gas, pyrolysis oil, and/or pyrolysis residue are not mutually exclusive and may be combined and present in any combination.

[0092] In an embodiment or in combination with any embodiment mentioned herein, the pyrolysis oil may predominantly comprise hydrocarbons having from 4 to 30 carbon atoms per molecule (e.g., C4 to C30 hydrocarbons). As used herein, the term “Cx” or “Cx hydrocarbon,” refers to a hydrocarbon compound including “x” total carbons per molecule, and encompasses all olefins, paraffins, aromatics, heterocyclic, and isomers having that number of carbon atoms. For example, each of normal, iso, and tert-butane and butene and butadiene molecules would fall under the general description “C4.” The pyrolysis oil may have a C4-C30 hydrocarbon content of at least 55, at least 60, at least 65, at least 70, at least 75, at least 80, at least 85, at least 90, or at least 95 weight percent based on the total weight of the pyrolysis oil stream.

[0093] In an embodiment or in combination with any embodiment mentioned herein, the pyrolysis oil can predominantly comprise C5 to C25 hydrocarbons, C5 to C22 hydrocarbons, or C5 to C20 hydrocarbons. For example, the pyrolysis oil may comprise at least 55, at least 60, at least 65, at least 70, at least 75, at least 80, at least 85, at least 90, or at least 95 weight percent of C5 to C25 hydrocarbons, C5 to C22 hydrocarbons, or C5 to C20 hydrocarbons, based on the total weight of the pyrolysis oil stream.

[0094] In an embodiment or in combination with any embodiment mentioned herein, the pyrolysis oil may have a mid-boiling point in the range of 75 to 250 °C, 90 to 225 °C, or 115 to 190 °C as measured according to ASTM D-5399. As used herein, “mid-boiling point” refers to the median boiling point temperature of the pyrolysis oil, where 50 percent by volume of the pyrolysis oil boils above the mid-boiling point and 50 percent by volume boils below the mid-boiling point.

[0095] In an embodiment or in combination with any embodiment mentioned herein, the boiling point range of the pyrolysis oil may be such that at least 90 percent of the pyrolysis oil boils off at a temperature of 250°C, of 280°C, of 290°C, of 300°C, or of 310°C, as measured according to ASTM D- 5399.

[0096] As noted above, the pyrolysis conditions, such as temperature, may be controlled so as to maximize the production of certain hydrocarbons and chemical compounds in the resulting pyrolysis gas and pyrolysis oil.

[0097] T urning to the pyrolysis gas, the pyrolysis gas can have a methane content in the range of 1 to 50 weight percent, 5 to 50 weight percent, or 15 to 45 weight percent, based on the total weight of the pyrolysis gas stream.

[0098] In an embodiment or in combination with any embodiment mentioned herein, the pyrolysis gas can have a C3 and/or C4 hydrocarbon content (including all hydrocarbons having 3 or 4 carbon atoms per molecule) in the range of 10 to 90 weight percent, 25 to 90 weight percent, or 25 to 80 weight percent, based on the total weight of the pyrolysis gas stream.

[0099] In an embodiment or in combination with any embodiment mentioned herein, the pyrolysis gas can have a combined ethylene and propylene content of at least 25, at least 40, at least 50, at least 60, at least 70, or at least 75 weight percent, based on the total weight of the pyrolysis gas stream.

[0100] Turning to the pyrolysis residue, in an embodiment or in combination with any embodiment mentioned herein, the pyrolysis residue comprises at least 20, at least 25, at least 30, at least 35, at least 40, at least 45, at least 50, at least 55, at least 60, at least 65, at least 70, at least 75, at least 80, or at least 85 weight percent of C20+ hydrocarbons based on the total weight of the pyrolysis residue. As used herein, “C20+ hydrocarbon” refers to hydrocarbon compounds containing at least 20 total carbons per molecule, and encompasses all olefins, paraffins, and isomers having that number of carbon atoms.

[0101] Generally, at least a portion of the pyrolysis gas stream, the pyrolysis oil steam, and/or the pyrolysis residue stream, may be routed to one or more other chemical processing facilities, including, for example, a cracking facility. In an embodiment or in combination with any embodiment mentioned herein, at least a portion of the pyrolysis gas stream may be routed to the cracker furnace of a cracking facility.

Cracking

[0102] As shown in FIG. 1 , at least a portion of one or more streams from the pyrolysis facility, including the pyrolysis oil stream and/or the pyrolysis gas stream, may be introduced into a cracking facility. As used herein, the term “cracking” refers to breaking down complex organic molecules into simpler molecules by the breaking of carbon-carbon bonds. A “cracking facility” is a facility that includes all equipment, lines, and controls necessary to carry out cracking of a feedstock derived from waste plastic. A cracking facility can include one or more cracker furnaces 14, a quench system 16 for cooling the cracked products, a compression system 18, and a downstream separation zone 20 including equipment used to process the effluent of the cracker furnace(s). As used herein, the terms “cracker” and “cracking” are used interchangeably.

[0103] In general, the cracker facility may include a cracker furnace 14, a quench system 16, a compression system 18 for forming a compressed stream 36, and a separation zone 20 downstream of the cracker furnace 14 for separating the furnace effluent into various end products, such as a recycle content hydrocarbons (r-hydrocarbons) stream. In an embodiment or in combination with any embodiment mentioned herein, at least a portion of the pyrolysis oil stream and/or the pyrolysis gas stream can be sent to the cracking facility. The pyrolysis oil stream may be introduced into an inlet of the cracker furnace 14, while the pyrolysis gas stream can be introduced into a location upstream or downstream of the furnace. The effluent from the cracker furnace 14 may be separated into various recycle content products in the downstream separator, as shown in FIG. 1 . When used, the pyrolysis oil stream and/or pyrolysis gas stream may optionally be combined with a stream of cracker feed to form the feed stream to the cracking facility.

[0104] In some embodiments, the cracker feed stream can include a hydrocarbon feed other than the pyrolysis gas stream and/or the pyrolysis oil stream in an amount of from 5 to 95 weight percent, 10 to 90 weight percent, or 15 to 85 weight percent, based on the total weight of the cracker feed. [0105] In an embodiment or in combination with any embodiment mentioned herein, the cracker facility may comprise a single cracking furnace, or it can have at least 2, or at least 3, or at least 4, or at least 5, or at least 6, or at least 7, or at least 8 or more cracking furnaces operated in parallel. Any one or each furnace(s) may be gas cracker, or a liquid cracker, or a split furnace.

[0106] The cracker feed stream, along with the pyrolysis oil stream and/or pyrolysis gas, may pass through the cracking furnace, wherein the hydrocarbon components therein are thermally cracked to form lighter hydrocarbons, including olefins such as ethylene, propylene, and/or butadiene. The residence time of the cracker stream in the furnace can be in the range of from 0.15 to 2 seconds, 0.20 to 1.75 seconds, or 0.25 to 1.5 seconds.

[0107] The temperature of the cracked olefin-containing effluent withdrawn from the furnace outlet can be in the range of from 730 to 900 °C, 750 to 875 °C, or 750 to 850 °C.

[0108] In an embodiment or in combination with any embodiment mentioned herein, the recycle content olefin-containing stream withdrawn from the separator in the cracking facility (as shown in FIG. 1) can comprise at least 10, at least 15, at least 20, at least 25, at least 30, at least 35, at least 40, at least 45, at least 50, at least 55, at least 60, at least 65, at least 70, at least 75, at least 80, at least 85, or at least 90 weight percent of recycle content C2 to C4 olefins, based on the total weight of the olefin-containing effluent stream. The recycle content olefin-containing stream may comprise predominantly recycle content ethylene, predominantly recycle content propylene, or predominantly recycle content ethylene and recycle content propylene, based on the total weight of the olefin-containing effluent stream. [0109] In an embodiment or in combination with any embodiment mentioned herein, when introduced into the cracker facility, the pyrolysis gas stream may be introduced into the inlet of the cracker furnace 14, or all or a portion of the pyrolysis gas stream may be introduced downstream of the furnace outlet, at a location upstream of or within the separation zone of the cracker facility. When introduced into or upstream of the separation zone, the pyrolysis gas can be introduced upstream of the last stage of compression in the compressor, or prior to the inlet of at least one fractionation column in a fractionation section of the separator.

[0110] Upon exiting the cracker furnace outlet, the olefin-containing effluent stream 32 may be cooled rapidly (e.g., quenched) in the quench system 16 in order to prevent production of large amounts of undesirable byproducts and to minimize fouling in downstream equipment. The quench system 16 can yield the quenched olefin-containing effluent stream 34 and a waste quench fluid stream that may comprise water, residual quench oil, and/or residual steam.

[0111] In an embodiment or in combination with any embodiment mentioned herein, at least a portion of one or more of the above streams may be introduced into one or more of the facilities shown in FIG. 1 , while, in other embodiments, all or a portion of the streams withdrawn from the separation zone of the cracking facility may be routed to further separation and/or storage, transportation, sale, and/or use.

Definitions

[0112] It should be understood that the following is not intended to be an exclusive list of defined terms. Other definitions may be provided in the foregoing description, such as, for example, when accompanying the use of a defined term in context.

[0113] As used herein, the terms “a,” “an,” and “the” mean one or more.

[0114] As used herein, the term “and/or,” when used in a list of two or more items, means that any one of the listed items can be employed by itself or any combination of two or more of the listed items can be employed. For example, if a composition is described as containing components A, B, and/or C, the composition can contain A alone; B alone; C alone; A and B in combination; A and C in combination, B and C in combination; or A, B, and C in combination.

[0115] As used herein, the phrase “at least a portion” includes at least a portion and up to and including the entire amount or time period.

[0116] As used herein, the term “bottom” refers to the physical location of a structure that is below the other noted structures within an enclosed structure. For example, a “bottom” stream is a stream taken from a vessel at a position that is lower elevation-wise to other streams taken from the vessel, such as an “overhead” stream.

[0117] As used herein, the term “chemical recycling” refers to a waste plastic recycling process that includes a step of chemically converting waste plastic polymers into lower molecular weight polymers, oligomers, monomers, and/or non-polymeric molecules (e.g., hydrogen, carbon monoxide, methane, ethane, propane, ethylene, and propylene) that are useful by themselves and/or are useful as feedstocks to another chemical production process(es). [0118] As used herein, the term “chemical recycling facility” refers to a facility for producing a recycle content product via chemical recycling of waste plastic.

[0119] As used herein, the term “co-located” refers to the characteristic of at least two objects being situated on a common physical site, and/or within one mile of each other.

[0120] As used herein, the terms “comprising,” “comprises,” and “comprise” are open-ended transition terms used to transition from a subject recited before the term to one or more elements recited after the term, where the element or elements listed after the transition term are not necessarily the only elements that make up the subject.

[0121] As used herein, the term “cracking” refers to breaking down complex organic molecules into simpler molecules by the breaking of carboncarbon bonds.

[0122] As used herein, the term “depleted” refers to having a concentration (on a dry weight basis) of a specific component that is less than the concentration of that component in a reference material or stream.

[0123] As used herein, the term “directly derived” refers to having at least one physical component originating from waste plastic.

[0124] As used herein, the term “enriched” refers to having a concentration (on a dry weight basis) of a specific component that is greater than the concentration of that component in a reference material or stream.

[0125] As used herein, the terms “exhaustion” or “exhausting” refer to methods for disposing of the specified stream by removing the stream from the facility. Exemplary exhaustion methods can include venting.

[0126] As used herein, the term “fluid” may encompass a liquid, a gas, a supercritical fluid, or a combination thereof.

[0127] As used herein, “Global Warming Potential” or “GWP” refers to a summation of Greenhouse Gas (GHG) emissions converted to CO2- equivalents. The units are kilograms CC>2-equivalent per functional unit (e.g., High Value Chemical Product type), and the functional unit is typically expressed as 1 kilogram product (kg CC>2-eq/kg).

[0128] As used herein, the term “halide” refers to a composition comprising a halogen atom bearing a negative charge (i.e., a halide ion).

[0129] As used herein, the term “halogen” or “halogens” refers to organic or inorganic compounds, ionic, or elemental species comprising at least one halogen atom.

[0130] As used herein, the terms “having,” “has,” and “have” have the same open-ended meaning as “comprising,” “comprises,” and “comprise” provided above.

[0131] As used herein, a “heat transfer medium loop” or “HTM loop” refers to a system comprising one or more heat exchangers through which a common HTM is circulated to a common HTM supply or a part of a larger system for the purpose of transferring heat and/or energy into and/or out of the chemical recycling process.

[0132] As used herein, the terms “including,” “include,” and “included” have the same open-ended meaning as “comprising,” “comprises,” and “comprise” provided above.

[0133] As used herein, the term “indirectly derived” refers to having an assigned recycle content i) that is attributable to waste plastic, but ii) that is not based on having a physical component originating from waste plastic. [0134] As used herein, the term “isolated” refers to the characteristic of an object or objects being by itself or themselves and separate from other materials, in motion or static.

[0135] As used herein, the term “light pyrolysis oil stream” refers to a pyrolysis oil stream that has had at least a portion of the pyrolysis residue removed therefrom.

[0136] As used herein, the terms “mixed plastic waste” and “MPW” refer to a mixture of at least two types of waste plastics including, but not limited to the following plastic types: polyethylene terephthalate (PET), one or more polyolefins (PO), and polyvinylchloride (PVC). [0137] As used herein, “non-aqueous” refers to a fluid containing less than five percent of molecular water by weight.

[0138] As used herein, the term “overhead” refers to the physical location of a structure that is above a maximum elevation of quantity of particulate plastic solids within an enclosed structure. For example, an “overhead” stream is a stream taken from a vessel at a position that is higher elevationwise to other streams taken from the vessel, such as a “bottom” stream.

[0139] As used herein, the term “partially processed waste plastic” means waste plastic that has been subjected to at least on automated or mechanized sorting, washing, or comminuted step or process. Partially processed waste plastics may originate from, for example, municipal recycling facilities (MRFs) or reclaimers. When partially processed waste plastic is provided to the chemical recycling facility, one or more preprocessing steps may me skipped.

[0140] As used herein, the term “physical recycling” (also known as “mechanical recycling”) refers to a waste plastic recycling process that includes a step of melting waste plastic and forming the molten plastic into a new intermediate product (e.g., pellets or sheets) and/or a new end product (e.g., bottles). Generally, physical recycling does not substantially change the chemical structure of the plastic, although some degradation is possible.

[0141] As used herein, the term “plastic” may include any organic synthetic polymers that are solid at 25°C and 1 atmosphere of pressure.

[0142] As used herein, the term “predominantly” means more than 50 percent by weight. For example, a predominantly propane stream, composition, feedstock, or product is a stream, composition, feedstock, or product that contains more than 50 weight percent propane.

[0143] As used herein, the term “preprocessing” refers to preparing waste plastic for chemical recycling using one or more of the following steps: (i) comminuting, (ii) particulating, (iii) washing, (iv) drying, and/or (v) separating. [0144] As used herein, the term “pyrolysis” refers to thermal decomposition of a feedstock of a biomass and/or a plastic material in solid or liquid form at elevated temperatures in an inert (i.e., substantially molecular oxygen free) atmosphere. [0145] As used herein, the term “pyrolysis char” refers to a carbon- containing composition obtained from pyrolysis that is solid at 200°C and 1 atm.

[0146] A “pyrolysis facility” is a facility that includes all equipment, lines, and controls necessary to carry out pyrolysis of waste plastic and feedstocks derived therefrom. In certain embodiments, the pyrolysis facility can comprise the liquification and pyrolysis reactor.

[0147] As used herein, the terms “pyrolysis gas” and “pygas” refer to a composition obtained from pyrolysis that is gaseous at 25°C at 1 atm.

[0148] As used herein, the term “pyrolysis heavy waxes” refers to C20+ hydrocarbons obtained from pyrolysis that are not pyrolysis char, pyrolysis gas, or pyrolysis oil.

[0149] As used herein, the terms “pyrolysis oil” or “pyoil” refers to a composition obtained from pyrolysis that is liquid at 25°C and 1 atm.

[0150] As used herein, the term “pyrolysis residue” refers to a composition obtained from pyrolysis that is not pyrolysis gas or pyrolysis oil and that comprises predominantly pyrolysis char and pyrolysis heavy waxes.

[0151] As used herein, the terms “recycle content” and “r-content” refer to being or comprising a composition that is directly and/or indirectly derived from waste plastic.

[0152] As used herein, the terms “r-pyrolysis gas” or “r-pygas” refer to being or comprising a pyrolysis gas that is directly and/or indirectly derived from waste plastic.

[0153] As used herein, the terms “r-pyrolysis oil” or “r-pyoil” refer to being or comprising a pyrolysis oil that is directly and/or indirectly derived from waste plastic.

[0154] As used herein, the terms “r-pyrolysis residue” refers to a pyrolysis residue that is directly and/or indirectly derived from waste plastic.

[0155] As used herein, the terms “r-pyrolysis vapors” refers to pyrolysis vapors that are directly and/or indirectly derived from waste plastic. [0156] As used herein, the terms “waste plastic” and “plastic waste” refer to used, scrap, and/or discarded plastic materials. The waste plastic fed to the chemical recycling facility may be unprocessed or partially processed. [0157] As used herein, the term “unprocessed waste plastic” means waste plastic that has not be subjected to any automated or mechanized sorting, washing, or comminuting. Examples of unprocessed waste plastic include waste plastic collected from household curbside plastic recycling bins or shared community plastic recycling containers.

[0158] As used herein, “downstream” means a target unit operation, vessel, or equipment that: a. is in fluid (liquid or gas) communication, or in piping communication, with an outlet stream from the radiant section of a cracker furnace, optionally through one or more intermediate unit operations, vessels, or equipment, or b. was in fluid (liquid or gas) communication, or in piping communication, with an outlet stream from the radiant section of a cracker furnace, optionally through one or more intermediate unit operations, vessels, or equipment, provided that the target unit operation, vessel, or equipment remains within the battery limits of the cracker facility (which includes the furnace and all associated downstream separation equipment).

CLAIMS NOT LIMITED TO DISCLOSED EMBODIMENTS

[0159] When a numerical sequence is indicated, it is to be understood that each number is modified the same as the first number or last number in the numerical sequence or in the sentence, e.g., each number is “at least,” or “up to” or “not more than” as the case may be; and each number is in an “or” relationship. For example, “at least 10, 20, 30, 40, 50, 75 wt.%...” means the same as “at least 10 wt.%, or at least 20 wt.%, or at least 30 wt.%, or at least 40 wt.%, or at least 50 wt.%, or at least 75 wt.%,” etc.; and “not more than 90 wt.%, 85, 70, 60...” means the same as “not more than 90 wt.%, or not more than 85 wt.%, or not more than 70 wt.%....” etc.; and “at least 1 %, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9% or 10% by weight...” means the same as “ at least 1 wt.%, or at least 2 wt.%, or at least 3 wt.% ...” etc.; and “at least 5, 10, 15, 20 and/or not more than 99, 95, 90 weight percent” means the same as “at least 5 wt.%, or at least 10 wt.%, or at least 15 wt.% or at least 20 wt.% and/or not more than 99 wt.%, or not more than 95 wt.%, or not more than 90 weight percent...” etc.

[0160] The preferred forms of the invention described above are to be used as illustration only and should not be used in a limiting sense to interpret the scope of the present invention. Modifications to the exemplary embodiments, set forth above, could be readily made by those skilled in the art without departing from the spirit of the present invention.

[0161] The inventors hereby state their intent to rely on the Doctrine of Equivalents to determine and assess the reasonably fair scope of the present invention as it pertains to any apparatus not materially departing from but outside the literal scope of the invention as set forth in the following claims.

Claims

What is claimed is -

1 . A chemical recycling process comprising:

(a) introducing a solid waste plastic into a melting and pyrolysis reactor;

(b) melting and pyrolyzing at least a portion of the solid waste plastic in the melting and pyrolysis reactor with heat from a common heat source to thereby produce a pyrolysis gas stream and a pyrolysis oil stream; and

(c) combining at least a portion of the pyrolysis oil stream with the solid waste plastic either -

(i) prior to the introducing in the melting and pyrolysis reactor, or

(ii) within the melting and pyrolysis reactor at a location upstream of a last off-take of pyrolysis gas from the melting and pyrolysis reactor.

2. The process according to claim 1 , wherein the melting and pyrolysis reactor comprises at least 2 reaction stages separated from one another by an upright weir and/or a vertical drop.

3. The process according to claim 2, wherein each of the reaction stages comprises an impeller, a paddle, or an auger system.

4. The process according to claim 2, wherein the melting and pyrolysis reactor comprises not more than not more than 20 reaction stages, wherein each of the reaction stages comprises a gas outlet for removing gases that evolve in each of the reaction stages.

5. The process according to claim 2, wherein the reaction stages comprise an initial reaction stage and at least one successive reaction stage downstream of the initial reaction stage, wherein the initial reaction stage is where the solid waste plastic is at least partially melted to form a liquefied plastic stream. The process according to claim 5, further comprising introducing the liquefied plastic stream into the successive reaction stage, wherein the viscosity of the liquefied plastic stream is increased within the successive reaction stage, and wherein the successive reaction stage has a higher temperature relative to the initial reaction stage. The process according to claim 5, wherein the reaction stages comprise at least at least 2, at least 3, or at least 4 successive reaction stages downstream of the initial reaction stage, wherein the temperatures within the melting and pyrolysis reactor increase with each successive reaction stage. The process according to claim 1 , wherein the melting and pyrolysis reactor comprises a feed inlet for receiving the solid waste plastic and at least one gas outlet for discharging a pyrolysis vapor stream comprising the pyrolysis gas stream, wherein the temperature of the gas outlet of the melting and pyrolysis reactor is at least 525°C, as measured within the interior of the gas outlet. The process according to claim 1 , wherein the solid waste plastic flows horizontality through the melting and pyrolysis reactor, and the melting and pyrolysis reactor comprises a plurality of gas outlets for discharging a pyrolysis vapor stream. A chemical recycling process comprising:

(a) introducing a solid waste plastic into a melting and pyrolysis reactor;

(b) melting and pyrolyzing at least a portion of the solid waste plastic in the melting and pyrolysis reactor to thereby produce a pyrolysis gas stream and a pyrolysis oil stream, wherein the melting and pyrolysis reactor comprises at least one auger for transporting the solid waste plastic and/or a liquefied waste plastic through at least a portion of the melting and pyrolysis reactor; and

(i) prior to the introducing in the melting and pyrolysis reactor, or

(ii) within the melting and pyrolysis reactor at a location upstream of a last off-take of pyrolysis gas from the melting and pyrolysis reactor. 1 . The process according to claim 10, wherein the melting and pyrolysis reactor comprises at least 2 reaction stages separated from one another by an upright weir and/or a vertical drop, and each of the reaction stages comprises an agitator comprising an impeller, a paddle, or an auger system, wherein at least one of the reaction stages comprises the auger as the agitator. 2. The process according to claim 10, wherein the reaction stages comprise an initial reaction stage and at least one successive reaction stage downstream of the initial reaction stage, wherein the initial reaction stage is where the solid waste plastic is at least partially melted to form a liquefied plastic stream. 3. The process according to claim 12, wherein the reaction stages comprise at least at least 2 successive reaction stages downstream of the initial reaction stage, wherein the temperatures within the melting and pyrolysis reactor increase with each successive reaction stage.

14. The process according to claim 10, wherein the melting and pyrolysis reactor comprises a feed inlet for receiving the solid waste plastic and a gas outlet for discharging a pyrolysis vapor stream comprising the pyrolysis gas stream, wherein the temperature of the gas outlet of the melting and pyrolysis reactor is at least 500 °C, as measured within the interior of the gas outlet.

15. The process according to claim 14, wherein the temperature of the gas outlet of the melting and pyrolysis reactor is not more than 1 ,000, not more than 950, not more than 900, not more than 850, or not more than 800 °C, as measured within the interior of the gas outlet.

16. The process according to claim 10, wherein the combining of step (c) occurs within the melting and pyrolysis reactor at a location upstream of a last off-take of pyrolysis gas from the melting and pyrolysis reactor.

17. A chemical recycling system comprising:

(a) a plastic feed mechanism for receiving and metering plastic particles;

(b) a pyrolysis reactor having a plastic feed inlet for receiving the plastic particles from the feed mechanism, a gas outlet for discharging pyrolysis vapors, and a liquid outlet for discharging pyrolysis liquids; and

(c) a heater for providing heat to the pyrolysis reactor, wherein the pyrolysis reactor comprises at least two stages separated from one another by an upright weir and/or a vertical drop, wherein each stage of the pyrolysis reactor includes an agitator for promoting mixing of a reaction medium and/or horizontal movement of the reaction medium through each stage of the pyrolysis reactor. The system according claim 17, wherein the agitator comprises an impeller, a paddle, or an auger system. The system according to claim 17, wherein the pyrolysis reactor further comprises a waste outlet for discharging a halogen-containing off-gas, wherein the waste outlet is upstream of the gas outlet. The system according to claim 17, further comprising a separator for separating at least a portion of the pyrolysis liquids into a pyrolysis oil stream and a pyrolysis residue.