Method for removing chlorine from mixed plastic waste

Abstract

Methods of removing chlorine from mixed plastic waste that may include a first polymer and a second chlorine-containing polymer are described. The method may include heating mixed plastic waste to obtain a molten mixed plastic waste stream. The molten mixed plastic waste stream may include molten plastic and a hydrogen chloride (HCl) gas. The surface area of the melt mixed plastic stream may be increased such that at least a portion of the HCl is released from the melt mixed plastic waste stream and a first product stream is produced. The first product stream may include less chlorine than the mixed plastic waste prior to heating.

Description

[0001] Cross - reference to related applications

[0002] This application claims the priority and the benefit of the filing date of European Patent Application No. 22210367, filed on November 29, 2022, which is incorporated herein by reference in its entirety. Technical Field

[0003] The present invention generally relates to a method for removing chlorine impurities from mixed plastic waste. The method may include heating the mixed plastic waste to obtain a molten mixed plastic waste stream. The molten mixed plastic waste stream may include molten plastic and hydrogen chloride (HCl) that may be contained within the molten plastic. The surface area of the molten mixed plastic stream may be increased such that at least a portion of the HCl may be released from the molten mixed plastic waste stream, and a first product stream may be produced. The first product stream may include less chlorine as compared to the mixed plastic waste prior to heating. Background Art

[0004] Mixed plastic waste may be sourced from household and / or industrial sources. The composition of the mixed plastic waste may include various types of plastics. For example, polyethylene terephthalate (PET), low density or high density polyethylene (PE), polypropylene (PP), polyvinyl chloride (PVC), polystyrene (PS), and other miscellaneous plastics from various post-consumer products (such as electronic waste, automotive waste, polyurethane foam packaging, carpet nylon, etc.). Other impurities may also be present in the mixed plastic waste, such as trace metals as compounding additives to enhance the performance of the polymerization process. Additionally, small amounts of non-plastics, such as paper, wood, and / or food residues, may be present.

[0005] The pyrolysis of waste mixed plastics is a process that includes decomposing plastics at high temperatures to produce pyrolysis oil (pyoil). The pyrolysis oil may be directly used as a liquid fuel or further processed to produce high-value chemicals. However, the pyrolysis oil produced from mixed plastics generally contains a large amount of highly reactive chemicals, which results in the rapid aging and / or formation of gums in the pyrolysis oil during transportation and further processing steps. Thus, in the presence of trace amounts of oxygen, it is quite common for the pyrolysis oil to cause fouling of the containers and / or chemical processing units in which it is being handled and / or processed. Not all plastics are suitable for pyrolysis processing. For example, PVC may contain up to 57% chlorine. Thus, the conversion of chlorinated polymers may be undesirable since the formed chlorinated derivatives may damage downstream process metallurgy if not treated. To remove plastics containing chlorinated products, a sorting process may be applied prior to the pyrolysis process. However, sorting can be inefficient and costly.

[0006] Methods for removing chlorides from mixed plastic waste have been described. For example, U.S. Patent Application Publication No. 2022 / 0010213 to Sun et al. describes a method of pyrolyzing a mixed plastic stream including PVC. The method removes chlorides in a vapor reactor in an initial melting reactor. In another example, Japanese Patent Application No. JP2003231886 to Takeyoshi et al. describes a thermal decomposition method of waste plastic oil, which suppresses the generation of organic volatile substances and evaporates chlorine contained in the mixed plastic waste. In yet another example, International Application Publication No. 2021 / 087059 to Wu et al. describes dehalogenating a mixed waste plastic feed by heating the plastic-containing feed to a temperature sufficient to release a halogen-containing waste stream and then pyrolyzing the dehalogenated feed.

[0007] Although there are methods for removing chlorine from mixed plastic waste, there remains a need for improvement in the art. SUMMARY OF THE INVENTION

[0008] Solutions to at least some of the problems associated with removing chlorine from mixed plastic waste have been found. In one aspect, the method of the present invention may include separating the steps of dehalogenating PVC and devolatilizing HCl. For example, PVC decomposition can be achieved in a reactor operating at high temperature and with a short residence time. The polymer melt product can be processed to increase its surface area (e.g., formed into multiple strands / fibers or droplets). By increasing the surface area of the polymer melt, enhanced mass transfer of HCl away from the polymer (e.g., devolatilization) can be obtained. HCl removal can be further assisted by operating the devolatilization device in a vacuum or with a hot gas purge (e.g., nitrogen (N2), carbon dioxide (CO2), or a reactive gas such as hydrogen (H2), ammonia (NH3), or the washed HCl gas / product gas from the process).

[0009] In one aspect of the present invention, a method for removing chlorine from mixed plastic waste comprising at least one chlorinated polymer is described. The method may comprise (a) heating mixed plastic waste that may comprise a first polymer (such as polyethylene (PE), polypropylene (PP), polyethylene terephthalate (PET), or polystyrene (PS), or any combination or blend thereof) and a second chlorinated polymer (such as polyvinyl chloride (PVC), polyvinylidene chloride (PVDC), chlorinated polyethylene (CPE), chlorosulfonated polyethylene (CSM), or chloroendic acid polyester, or any combination or blend thereof) to obtain a molten mixed plastic waste stream. In a preferred aspect, the second chlorinated polymer is PVC. The molten mixed plastic stream may comprise molten plastic and hydrogen chloride (HCl). The HCl may be included within the molten plastic. The heating and melting may be carried out in an extruder (such as a single-screw extruder, a twin-screw extruder, or an auger extruder), a kneader, or a heat exchange unit that may comprise a static mixer, or a batch reactor.

[0010] In step (b), the surface area of the molten mixed plastic waste stream may be increased to release at least a portion of the HCl from the molten mixed plastic waste stream, thereby producing a first product stream. The released HCl may be in the gas phase or the liquid phase, preferably in the gas phase. The surface area increase may be carried out in a container that is in fluid communication with the heating / melting unit (such as an extruder, a kneader, or a heat exchange unit). For example, a die may be placed at the end of the extruder, the kneader, or the heat exchange unit, and the molten mixed plastic waste stream may flow through the die and into the container to form strands / fibers or droplets of the molten mixed plastic waste stream. The strands / fibers may preferably have a diameter of 5 millimeters (mm) or less, more preferably 1 mm or less. In some aspects, the strands / fibers may be formed into droplets. The surface area increase may be carried out in the presence of a carrier gas that contacts the molten mixed plastic waste stream and carries the HCl away from the molten mixed plastic waste stream. The carrier gas may be an inert gas (such as nitrogen (N2) or carbon dioxide (CO2), where N2 is preferred), a reactive gas (such as preferably hydrogen (H2), ammonia (NH3), or a washed HCl-free gas product gas obtained from the process of increasing the surface area), or a combination thereof. In another aspect, the surface area may be increased under vacuum. The surface area increasing container may be a reactor comprising a first inlet for the molten mixed plastic waste stream, a second inlet for the carrier gas, a first outlet for the first product stream, and a second outlet for the carrier gas that may comprise HCl obtained from the chlorinated polymer. The second outlet may be located above the first outlet. In some embodiments, a horizontal extruder or a vertical extruder may be located above the first outlet of the first product stream. In another aspect, the container comprises a conveyor belt that moves the strands / fibers through the container. In some aspects, the container may rotate.

[0011] Heating / melting and / or surface area increase (e.g., steps (a) and (b)) can each be carried out separately at least up to the melting temperature of the mixed plastic waste, which is at most 350 °C, preferably 200 °C to 325 °C. Optionally, the residence time for heating / melting and / or surface area increase (e.g., steps (a) and (b)) can be 30 minutes or less, preferably 15 minutes or less. The first product stream can include less chlorine when compared to the molten mixed plastic waste and / or the original mixed plastic waste (e.g., the mixed plastic waste of step (a)). Increasing the surface area of the molten mixed plastic waste stream can include forming strands / fibers and / or droplets of the molten mixed plastic waste stream. In some aspects, the first product stream can be subjected to a depolymerization reaction to produce a second product stream that can include oligomers (e.g., oligomers having an average MW of less than 20,000 g / mol, preferably less than 10,000 g / mol). The second product stream can be further processed by filtration, centrifugation, decantation / sedimentation, and / or washing with water or caustic solution to remove insoluble substances, soluble organic substances, inorganic chlorides, or combinations thereof.

[0012] Other embodiments of the invention are discussed throughout this application. Any embodiment discussed with respect to one aspect of the invention is also applicable to other aspects of the invention, and vice versa. Each embodiment described herein is understood to be an embodiment of the invention that is applicable to other aspects of the invention. It is contemplated that any embodiment or aspect discussed herein can be combined with any other embodiment or aspect discussed herein and / or implemented with respect to any method or composition of the invention, and vice versa. Additionally, the compositions of the invention can be used to implement the methods of the invention.

[0013] The following includes definitions of various terms and phrases used throughout this specification.

[0014] The term "about" or "approximately" is defined as being close to, as understood by one of ordinary skill in the art. In one non-limiting embodiment, the term is defined as within 10%, preferably within 5%, more preferably within 1%, and most preferably within 0.5%.

[0015] The terms "weight %", "volume %", or "mole %" refer, respectively, to the weight percentage, volume percentage, or mole percentage of a component based on the total weight, total volume, or total moles of the material including the component. In a non-limiting example, 10 grams of a component in 100 grams of material is a 10 weight % component.

[0016] The term "substantially" and its variants are defined to include ranges within 10%, within 5%, within 1%, or within 0.5%.

[0017] When used in the claims and / or the specification, the terms "suppress" or "reduce / diminish" or "prevent" or "avoid" or any variations of these terms include any measurable reduction / diminishment or complete suppression to achieve the desired result.

[0018] As used in the specification and / or the claims, the term "effective" means sufficient to achieve the desired, intended or predetermined result.

[0019] When used in conjunction with any of the terms "comprising", "including", "containing" or "having" in the claims or the specification, the use of the word "a" or "an" may mean "one", but it is also consistent with the meanings of "one or more", "at least one" and "one or more than one".

[0020] The words "comprising", "having", "including" or "containing" and any forms thereof are inclusive or open-ended and do not exclude additional unspecified elements or method steps.

[0021] The method of the present invention may "comprise", "consist essentially of" or "consist of" the specific ingredients, components, compositions, etc. disclosed throughout the specification. With respect to the transitional phrase "consist essentially of", in one non-limiting aspect, a basic and novel characteristic of the method of the present invention is the ability to remove chlorine from mixed plastic waste.

[0022] Other objects, features and advantages of the present invention will become apparent from the following drawings, detailed description and examples. However, it should be understood that the drawings, detailed description and examples, although indicating specific embodiments of the present invention, are given by way of illustration only and are not intended to be limiting. Additionally, variations and modifications within the spirit and scope of the present invention in accordance with the detailed description are expected to be apparent to those skilled in the art. In other embodiments, the features of specific embodiments may be combined with the features of other embodiments. For example, the features of one embodiment may be combined with the features of any of the other embodiments. In other embodiments, additional features may be added to the specific embodiments described herein. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] With the benefit of the following detailed description and with reference to the accompanying drawings, the advantages of the present invention may be apparent to those skilled in the art.

[0024] Figure 1 A schematic diagram of a chlorine removal system using the method of the present invention is shown. The system includes a dehalogenation unit (e.g., a reactor) located upstream of and perpendicular to a volatilization unit (e.g., a container).

[0025] Figure 2Schematic diagram of a chlorine removal system using the method of the present invention. The system includes a dehalogenation unit located upstream and above the volatilization unit and in series.

[0026] Figure 3 Schematic diagram of a chlorine removal system using the method of the present invention. The system includes a dehalogenation unit located upstream of and in series with the volatilization unit, and the volatilization unit includes a material moving device (such as a conveyor).

[0027] Figure 4 Schematic diagram of a chlorine removal system using the method of the present invention. The system includes a dehalogenation unit located upstream of the rotary volatilization unit.

[0028] Figure 5 Schematic diagram showing a chlorine removal combined depolymerization unit and an optional purification unit.

[0029] Although the present invention is susceptible to various modifications and alternative forms, specific embodiments thereof are shown by way of example in the drawings. The drawings may not be drawn to scale. Detailed Description

[0030] The chemical recycling of mixed plastic waste (MPW) involves heat-treating MPW to produce hydrocarbon liquids and waxes, and mixing the above with a conventional hydrocarbon stream for processing in a petrochemical complex. The presence of PVC in MPW results in the formation of organic and inorganic chlorides in MPW-derived hydrocarbons. This limits the amount of MPW that can be recycled. Solutions to at least some of the problems associated with removing chlorine from MPW have been found. In one aspect, the present invention may include a method for removing chlorine from MPW based on separating the dehalogenation of chlorine-containing polymers from the devolatilization of HCl in two separate unit operations. The chlorine-containing polymer may be melted at a high temperature and a short residence time. The polymer melt product may be processed to have an increased surface area (such as formed into strands / fibers and / or droplets). The increased surface area may provide the advantage of a high surface area to enhance mass transfer (such as devolatilization) of HCl from the fibers. In some aspects, HCl removal may be carried out under vacuum or using a hot gas purge.

[0031] These and other non-limiting aspects of the present invention are discussed in further detail in the following sections.

[0032] Reference Figure 1 , system 100 includes a dehalogenation unit 102 and a devolatilization unit 104. The MPW stream 106 may enter the dehalogenation unit 102. As shown, the dehalogenation unit 102 may be arranged perpendicular to the devolatilization unit 104. Other configurations are shown in Figures 2 - 4Among them, the MPW stream 106 may include one or more chlorine-free polymers and at least one chlorine-containing polymer. The chlorine-free polymer (such as the first polymer) may include polyethylene terephthalate (PET), low-density and high-density polyethylene (PE), polypropylene (PP), polystyrene (PS), or a combination thereof, and / or other miscellaneous plastics. Non-limiting examples of the chlorine-containing polymer include polyvinyl chloride (PVC), polyvinylidene chloride (PVDC), chlorinated polyethylene (CPE), chlorosulfonated polyethylene (CSM), or chlorendic acid polyester, or any combination or blend thereof. In a preferred aspect, the chlorine-containing polymer is PVC. Other miscellaneous plastics may be present in the MPW stream, such as acrylonitrile butadiene styrene, polyurethane foam packaging, carpet nylon, and / or polysulfone found in electronic waste. The MPW stream 106 may also include impurities. Non-limiting examples of impurities include paper, wood, aluminum foil, some metal conductive fillers, and / or halogenated or non-halogenated flame retardants. The MPW stream may be in solid form or in a flowable form (such as a low-viscosity, low-flowability material).

[0033] The dehalogenation unit 102 (reactor) can be any unit capable of melting the solid MPW. Non-limiting examples of the dehalogenation unit may include an extruder, a kneader, a heat exchange unit including a static mixer, or a batch reactor. Non-limiting examples of the extruder may include a single-screw or twin-screw or auger reactor having a ribbon, paddle-type, other configuration, intermittent, or shaftless flight geometry. In the dehalogenation unit 102, the MPW stream 106 can be heated to a temperature sufficient to melt the MPW stream with agitation. The melting temperature can be at most 350 °C, or 200 °C to 325 °C, or 200 °C, 225 °C, 250 °C, 275 °C, 300 °C, 325 °C, 350 °C, or any range or value therebetween. The residence time of the MPW stream 108 melted in the dehalogenation unit 102 depends on the temperature. A shorter residence time can be used when operating at a higher temperature. For example, a residence time of 1 minute or less at 300 °C is sufficient, while at 250 °C, a residence time of at least 10 minutes is required. Generally, the residence time can be 30 minutes or less, 25 minutes or less, 20 minutes or less, 15 minutes or less, 10 minutes or less, or 5 minutes or less, or 0.1 minute to 30 minutes, any value or range therebetween. A short residence time in the dehalogenation unit 102 provides the advantage of limiting the side reaction of HCl (formed during melting) reacting with the MPW stream to produce additional inorganic chlorides and organic halides. In other aspects, the residence time can be longer than 30 minutes (such as 35, 40, 45, 50, 55, 60, 70, 80, 90, 100, 110, 120 minutes, or longer).

[0034] As the molten MPW stream 108 exits the dehalogenation unit 102 and enters the devolatilization unit 104, the surface area of the molten MPW can be increased by applying pressure to the molten MPW stream. For example, the molten MPW can pass through one or more orifices 110 to form strands / fibers or droplets 112. Forming strands / fibers or droplets can increase the surface area of the molten MPW stream 108 and allow the release of HCl entrained in the molten polymer. The orifices can be of any shape or size (e.g., circular, oval, elongated, spherical, etc.). In some embodiments, the orifices are part of a die coupled to the dehalogenation unit 102. For example, the dehalogenation unit can include an extruder having a die attached to the end of the extruder. In some embodiments, the dehalogenation unit can be a kneader that includes a discharge die at the kneader outlet. In another aspect, the dehalogenation unit can be a heat exchanger unit that has a static mixer and a discharge die at the heat exchanger outlet. In certain aspects, the dehalogenation unit can be a batch reactor that includes a discharge die. In other aspects, the dehalogenation unit can be a batch reactor, a kneader, a heat exchanger with a static mixer, in combination with an extruder and a die. The strands / fibers 112 can have a diameter of 5 mm or less, or from 0.1 mm to 5 mm, or 0.1 mm, 0.5 mm, 1 mm, 1.5 mm, 2 mm, 2.5 mm, 3 mm, 3.5 mm, 4 mm, 4.5 mm, 5 mm, or any value or range therebetween. In other aspects, the strands / fibers 112 can have a diameter greater than 5 mm, such as 6, 7, 8, 9, 10, 15, 20 mm or greater.

[0035] The strand / fiber 112 can exit the orifice 110 and enter the devolatilization unit 104. The devolatilization unit 104 can be integrated with the dehalogenation unit 102 such that the strand / fiber 112 is not exposed to air (e.g., one unit has two chambers or is connected by a die). The devolatilization unit 104 can be a vessel, a flash evaporator, a wiped film evaporator, or the like that allows the removal of vapor from a vessel or reaction stream. In some aspects, the devolatilization unit 104 can include an electrically heated mesh or sieve tray to facilitate heat transfer. Such trays can also help support the strands / fibers 112 as they flow through the devolatilization unit 104. As the strand / fiber 112 is formed and enters the devolatilization unit 104, HCl can be released from the fiber to produce a first product stream 114. In some aspects, the devolatilization unit inlet can have a splash guard, a swirl disk, or the like, against which the strand / fiber impinges and ejects and is further carried away by a carrier gas. In some embodiments, the strand / fiber 112 is a droplet (not shown). The droplet can have a diameter similar to that of the strand / fiber. The HCl can include gaseous HCl, liquid HCl, or a mixture thereof. The removal of HCl can be carried out under vacuum or using a carrier gas. The vacuum pressure can be 50 to 760 mm Hg (absolute), or 100, 200, 300, 500, 550, 600, 650, 700, 750, 760 mm Hg (absolute) or any value or range therebetween. The carrier gas can be an inert gas and / or a reactive gas. The inert gas can include N2 and / or CO2. Non-limiting examples of the reactive gas can include H2, NH3, or the washed product gas (without HCl) obtained from the devolatilization unit 104. The temperature of the carrier gas can be 200°C to 450°C, or 200°C, 225°C, 250°C, 275°C, 300°C, 325°C, 350°C, 375°C, 400°C, 425°C, 450°C or any value or range therebetween. As shown, the HCl vapor stream 118 outlet is located above the carrier gas 116 inlet, thus allowing the countercurrent flow of the carrier gas to sweep the HCl upward and exit the devolatilization unit 104 as the HCl vapor stream 118. The HCl-containing vapor stream 118 can be further processed (e.g., a washed vapor stream). The devolatilization temperature can be higher than the melting point of the MPW. For example, the devolatilization temperature can be up to 450°C, 400°C, 350°C, or 200°C to 450°C, or 200°C, 225°C, 250°C, 275°C, 300°C, 325°C, 350°C, 400°C, 425°C, 450°C or any range or value therebetween. The length of the devolatilization unit 104 and / or the residence time in the devolatilization unit can be based on the feed rate from the dehalogenation unit 102 and / or the diameter of the fiber.For example, the residence time of the fibers / strands 112 in the devolatilization unit 104 at the devolatilization temperature can be 30 minutes or less, 25 minutes or less, 20 minutes or less, 15 minutes or less, 10 minutes or less, or 5 minutes or less, or 0.1 minutes to 30 minutes, any value or range therebetween. The first product stream 114 can exit the devolatilization unit and be further processed, stored, shipped, etc.

[0036] refer to Figure 2 , 3 and 4, showing variations of the configuration of the dehalogenation unit 102 and the devolatilization unit 104. Unless otherwise indicated, Figure 1 The same figure numbers are used and refer to the same streams and units. Figure 2 , system 200 shows a dehalogenation unit 102 located upstream of a devolatilization unit 104 and connected in series or in parallel therewith. For example, a vertical extruder may be located upstream of the vertical devolatilization unit. Figure 3 , the system 300 includes a dehalogenation unit 102 located upstream and in series with a devolatilization unit 104, which may include a conveyor unit 302. As the strands / fibers 112 enter the devolatilization unit 104, they may contact a conveyor belt 304 of the conveyor unit 302 that operates within the devolatilization unit. The conveyor belt 304 may be coated with a composition that provides a non-stick and release property for the strands / fibers 112 at high temperatures. Non-limiting examples of non-stick / release coatings include silicones, and the like. The carrier gas 116 may enter the devolatilization unit 104 such that the flow is cross-flow with the polymer fiber flow. As shown, the carrier gas 116 may be provided below the conveyor belt 304. The conveyor belt speed may provide control over the residence time of the strands / fibers 112 in the devolatilization unit 104. Reference Figure 4 , system 400 includes a dehalogenation unit 102 located upstream of and in series with a rotatable devolatilization unit 104. For example, the devolatilization unit 104 can be a rotary kiln. The rotation speed and angle of the devolatilization unit 104 can control the residence time of the strands / fibers 112 to achieve mass transfer of HCl. The flow of carrier gas 116 can be countercurrent or cocurrent.

[0037] refer to Figure 5 , system 500 illustrates further processing of first product stream 114. Figure 5 middle, Figures 1 - 4The devolatilization unit is in fluid communication with the depolymerization unit 502. A first product stream 114 can leave the devolatilization unit 104 and enter the depolymerization unit 502. In the depolymerization unit 502, the first product stream 114 can be subjected to conditions suitable for depolymerizing the polymer in the first product stream to produce a second product stream 504. The second product stream 504 can include oligomers obtained from the depolymerized polymer. The depolymerization conditions can include a temperature of 300 °C to 450 °C, or 300 °C, 325 °C, 350 °C, 375 °C, 400 °C, 425 °C, 450 °C or any value or range therebetween and a pressure of 0.5 MPa or less (including vacuum). In addition to oligomers, the second product stream 504 can include impurities. Non-limiting examples of impurities can include insoluble substances, soluble organic substances, inorganic chlorides, or combinations thereof. The second product stream 504 can leave the depolymerization unit 502 and enter the purification unit 506. In the purification unit 506, the second product stream 504 can be further processed to remove impurities. Non-limiting examples of purification methods can include filtration, centrifugation, decantation / sedimentation, washing with water or caustic solution, and / or combinations thereof.

[0038] The system 100-500 can include one or more heating and / or cooling devices (such as insulators, electric heaters, jacket heat exchangers in the walls) or controllers (such as computers, flow valves, automatic valves, etc.) that can be used to control the temperature, pressure, and fluid flow rate of the units. Although only one unit is shown, it should be understood that multiple units (such as multiple devolatilization units or multiple dehalogenation units) can be used.

[0039] Although the embodiments of the present application and their advantages have been described in detail, it should be understood that various changes, substitutions, and alterations can be made herein without departing from the spirit and scope of the embodiments as defined by the appended claims. In addition, the scope of the present application is not intended to be limited to the specific embodiments of the processes, machines, manufactures, compositions of matter, means, methods, and steps described in the specification. As will be readily understood by those of ordinary skill in the art from the foregoing disclosure, processes, machines, manufactures, compositions of matter, means, methods, or steps that perform substantially the same function or achieve substantially the same result as the corresponding embodiments described herein can be utilized, whether currently existing or later developed. Accordingly, the appended claims are intended to include such processes, machines, manufactures, compositions of matter, means, methods, or steps within their scope.

Claims

1. A method for removing chlorine from a mixed plastic waste containing a first polymer and a second chlorine-containing polymer, the method comprising: (a) heating the mixed plastic waste to obtain a molten mixed plastic waste stream containing molten plastic and hydrogen chloride (HCl); and (b) increasing the surface area of the molten mixed plastic waste stream to release at least a portion of the HCl from the molten mixed plastic waste stream and producing a first product stream containing less chlorine than the mixed plastic waste of step (a).

2. The method according to claim 1, wherein increasing the surface area of the molten mixed plastic waste stream comprises forming strands / fibers or droplets of the molten mixed plastic waste stream.

3. The method according to any one of claims 1 to 2, wherein step (a) is carried out at least in part in an extruder, a kneader or a heat exchange unit comprising a static mixer or a batch reactor, and step (b) is carried out at least in part in a container in fluid communication with the extruder, the kneader or the heat exchange unit comprising a static mixer or a batch reactor.

4. The method according to claim 3, wherein a die is placed at the end of the extruder, the kneader or the heat exchange unit, and wherein the molten mixed plastic waste stream flows through the die and into the container to form strands / fibers or droplets of the molten mixed plastic waste stream, wherein the strands / fibers preferably have a diameter of 5 millimeters (mm) or less, more preferably 1 mm or less, and wherein the strands / fibers are further formed into droplets.

5. The method according to any one of claims 3 to 4, wherein step (a) is carried out in the extruder, and wherein the extruder is a single-screw extruder, a twin-screw extruder or an auger extruder.

6. The method according to any one of claims 1 to 5, wherein steps (a) and (b) are each carried out separately at a melting temperature of the mixed plastic waste of at most 350 °C, preferably 200 °C to 325 °C, and optionally wherein the residence time of steps (a) and (b) is each separately 30 minutes or less, preferably 15 minutes or less.

7. The method according to any one of claims 1 to 6, wherein step (b) is carried out in the presence of a carrier gas that contacts the molten mixed plastic waste stream and carries the HCl away from the molten mixed plastic waste stream, preferably wherein the carrier gas comprises: an inert gas, preferably nitrogen (N2) or carbon dioxide (CO2); and / or a reactive gas, preferably hydrogen (H2), ammonia (NH3) or a washed HCl product gas obtained from step (b).

8. The method according to claim 7, wherein step (b) is carried out in a reactor comprising: a first inlet for the molten mixed plastic waste stream; a second inlet for the carrier gas; a first outlet for the first product stream; and a second outlet for the carrier gas containing HCl obtained from the chlorine-containing polymer, wherein the second outlet is located above the first outlet.

9. The method according to claim 8, wherein step (a) is carried out in an extruder, and wherein the extruder is a horizontal extruder or a vertical extruder, and wherein the extruder is located above the first outlet of the first product stream.

10. The method according to any one of claims 8 to 9, wherein the reactor comprises a conveyor belt, and wherein the molten mixed plastic waste stream from step (b) contacts the conveyor belt, or wherein the reactor is rotatable.

11. The method according to any one of claims 1 to 10, wherein the first product stream undergoes a depolymerization reaction to produce a second product stream comprising oligomers.

12. The method according to claim 11, wherein the second product stream is further processed by filtration, centrifugation, or washing with water or a caustic solution to remove insoluble substances, soluble organic substances, inorganic chlorides, or combinations thereof.

13. The method according to any one of claims 1 to 12, wherein: the first polymer comprises polyethylene (PE), polypropylene (PP), polyethylene terephthalate (PET), or polystyrene (PS), or any combination or blend thereof; and the second chlorinated polymer comprises polyvinyl chloride (PVC), polyvinylidene chloride (PVDC), chlorinated polyethylene (CPE), chlorosulfonated polyethylene (CSM), or chlorendic polyester, or any combination or blend thereof.

14. The method according to claim 13, wherein the second chlorinated polymer is PVC.

15. A system for performing the method according to any one of claims 1 to 14, the system comprising: an extruder configured to produce the molten mixed waste plastic stream comprising the molten plastic and HCl; a die in fluid communication with the extruder, the die being capable of forming strands / fibers or droplets of the molten mixed plastic waste stream; and a container in fluid communication with the die, the container being configured to remove HCl from the molten mixed plastic waste stream.

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