Granular plastic solid processing device and method

Abstract

A facility and system for processing particulate plastic solids obtained from a mixed waste plastic separation system is provided. The facility includes at least one enclosed structure and an elongated overhead conveyor associated with the at least one enclosed structure, the elongated overhead conveyor being configured to selectively deposit the particulate plastic solids into a plastic solids transport system that interconnects the processing facility with a plastics chemical recycling facility and / or at least one stockpile within the at least one enclosed structure.

Description

Background Art

[0001] Embodiments generally relate to facilities and systems for processing particulate plastic solids obtained from a mixed waste plastic separation system. In particular, the particulate plastic solids processing facility includes at least one enclosed structure and an elongated overhead conveyor associated with the at least one enclosed structure, the elongated overhead conveyor configured to selectively deposit the particulate plastic solids into a plastic solids transport system that interconnects the processing facility with a plastics chemical recycling facility and / or at least one stockpile within the at least one enclosed structure.

[0002] Recycling of plastic materials is considered highly desirable in many aspects of society. In addition to reducing the need for petroleum products to create virgin plastic materials, recycling also offers health and environmental benefits. Recycling initiatives often raise public awareness of the importance of discarding used plastics, thereby reducing the amount of waste in the environment. Recycling also saves landfill space and / or reduces greenhouse gas emissions from municipal incinerators. An increasing number of cities are mandating the recycling of various materials, including plastics. Consequently, in some areas, sanitation providers are responsible for collecting and processing recyclable materials.

[0003] Typically, once collected, recyclable materials are sent to a municipal recycling facility (also called a material recovery facility or MRF), where at least some attempt is made to sort them into bulk quantities of similar materials. For example, colored plastics can be separated from clear plastics. Glass, paper, and metal can be separated from plastics. Polyethylene terephthalate plastics can be separated from other types of plastics. Typically, at least some initial aspects of this sorting are performed manually. In other aspects, machines including light sorters and magnetic sorters are used to perform a more refined selection of the various materials present in the recyclables.

[0004] Initially sorted plastics can be further processed to recover certain plastics with high purity (e.g., >99%). These finer separations can be performed by plastic recycling facilities. However, in addition to producing high-purity plastics, plastic recycling facilities often generate lower-value or waste streams that are not sufficiently pure to allow them to be physically recycled.

[0005] In many aspects of society, there is a push for manufacturers to create products that include some recycled content. However, as mentioned above, recycled content is primarily limited to products made through physical recycling processes. For many manufacturers, incorporating recycled content into their products is impractical, or even impossible, due to the chemical structure of the plastic being incompatible with its manufacturing methods. Therefore, there is a need in the art for a method of recycling plastic materials so that the recycled plastic can be used to create new materials with recycled content, rather than being limited to having the same chemical structure as the original plastic material. Summary of the Invention

[0006] According to one embodiment, a facility for processing plastic solids separated from mixed plastic waste is provided. The facility includes an enclosed structure and an elongated overhead conveyor associated with the enclosed structure. The overhead conveyor is configured to selectively deposit particulate plastic solids into (a) a plastic solids transport system and / or (b) at least one particulate plastic solids stockpile at various locations along the length of the overhead conveyor.

[0007] According to another embodiment, a facility for processing a polyethylene terephthalate (PET)-rich stream and a polyethylene terephthalate (PET)-depleted stream received from a mixed plastic waste separation system is provided. The facility includes first and second enclosed structures, and first and second elongated overhead conveyors associated with the first and second enclosed structures, respectively. The elongated overhead conveyors are configured to selectively deposit the PET-rich stream and the PET-depleted stream received from the mixed plastic waste separation system into (a) first and second plastic solids transport systems and / or (b) first and second granular plastic solids stockpiles at different locations along the length of the overhead conveyors.

[0008] According to yet another embodiment, a plastic material transport system is provided that includes first and second transport systems configured to transport separate streams of particulate plastic solids. The first transport system is configured to transport the polyethylene terephthalate (PET)-rich stream between a particulate plastic solids processing facility and a solvolysis facility. The second transport system is configured to transport the PET-depleted stream between the particulate plastic solids processing facility and at least one of a partial oxidation gasification facility and a pyrolysis facility.

[0009] According to yet another embodiment, a method for processing particulate plastic solids separated from mixed plastic waste is provided. The method includes loading particulate plastic solids received from a mixed plastic waste separation system onto an elongated overhead conveyor associated with an enclosed structure. The particulate plastic solids are transported along the length of the enclosed structure using the overhead conveyor. The particulate plastic solids are deposited within the enclosed structure into at least one of: (a) a plastic solids transport system and (b) at least one particulate plastic solids stockpile at one or more locations along the length of the conveyor.

[0010] According to yet another embodiment, a method for processing a polyethylene terephthalate (PET)-rich solids stream and a polyethylene terephthalate (PET)-depleted solids stream received from a mixed plastic waste separation system is provided. The method includes loading the PET-rich solids stream onto a first elongated conveyor associated with a first enclosed structure. The first conveyor is located at an elevated position within the first enclosed structure. The PET-rich solids stream is transported within the first enclosed structure using the first conveyor. The PET-rich solids stream is selectively deposited within the first enclosed structure into at least one of: (a) a PET-rich solids transport system and (b) at least one PET-rich solids stockpile at one or more locations along the length of the conveyor. The PET-depleted solids stream is loaded onto a second elongated conveyor located within a second enclosed structure. The second conveyor is located at an elevated position within the second enclosed structure and extends substantially the length thereof. A second conveyor is used to transport a polyethylene terephthalate-depleted solids stream within a second enclosure. The polyethylene terephthalate-depleted solids stream is selectively deposited within the second enclosure into at least one of: (a) a polyethylene terephthalate-depleted solids transport system and (b) at least one polyethylene terephthalate-depleted solids inventory pile at one or more locations along the length of the conveyor.

[0011] In yet another embodiment, a method for distributing a stream containing particulate plastic solids to one or more plastic chemical recovery facilities is provided. The method includes directing a polyethylene terephthalate (PET)-rich solids stream from a PET solids processing facility to a solvolysis facility. The PET-depleted solids stream from the PET solids processing facility is directed to at least one of a partial oxidation gasification facility and a pyrolysis facility. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 (Fig. 1) depicts a general process for separating mixed plastic waste (MPW) into a polyethylene terephthalate (PET)-rich stream and a PET-depleted stream according to one embodiment of the present invention;

[0013] Figure 2 Depicts a general process for separating MPW into a PET-rich stream and a PET-depleted stream using two density separation stages according to one embodiment of the present invention;

[0014] Figure 3 Describes a detailed process for separating MPW into a PET-rich stream and a PET-depleted stream according to one embodiment of the present invention;

[0015] Figure 4Describes a detailed process for separating MPW into a PET-rich stream and a PET-depleted stream according to one embodiment of the present invention;

[0016] Figure 5 Describes a detailed process for separating MPW into a PET-rich stream and a PET-depleted stream according to one embodiment of the present invention;

[0017] Figure 6 Describes a detailed process for separating MPW into a PET-rich stream and a PET-depleted stream according to one embodiment of the present invention;

[0018] Figure 7 Describes a detailed process for separating MPW into a PET-rich stream and a PET-depleted stream according to one embodiment of the present invention;

[0019] Figure 8 Depicts a general process for separating MPW into a PET-rich stream and a PET-depleted stream according to one embodiment of the present invention;

[0020] Figure 9 Depicts a general process for separating MPW into a PET-rich stream and a PET-depleted stream using two density separation stages according to one embodiment of the present invention;

[0021] Figure 10 Depicting a plastic separation facility and process according to one embodiment of the present invention;

[0022] Figure 11 depicts an arrangement of a waste plastic separation system, a granular plastic solids processing facility, and a chemical recycling facility according to one embodiment of the present invention;

[0023] Figure 12 Depicting a granular plastic solids processing facility and process according to one embodiment of the present invention;

[0024] Figure 13 Depicts a general process for chemical recovery of MPW according to one embodiment of the present invention;

[0025] Figure 14 depicts a general density separation stage according to one embodiment of the present invention; and

[0026] Figure 15 A granular plastic solids processing facility and process according to one embodiment of the present invention is depicted. DETAILED DESCRIPTION

[0027] When indicating a sequence of numbers, it should be understood that each number is modified to be the same as the first or last number and is in an "or" relationship, that is, each number is "at least", "at most" or "not more than", as the case may be. For example, "at least 10 wt%, 20, 30, 40, 50, 75 ..." has the same meaning 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.

[0028] Unless otherwise indicated, all concentrations or amounts are by weight.

[0029] The weight percentages expressed as MPW are the weight of MPW fed to the first stage separation before the addition of any diluent / solution (eg salt or caustic solution).

[0030] References to MPW throughout the specification also provide support for granular plastic or MPW granules or reduced plastic or the plastic feedstock to the separation process. For example, references to component weight percentages in MPW also describe and provide support for the same weight percentages of granular plastic or reduced plastic or the plastic that is fed to the first stage of separation prior to mixing them with the caustic or salt solution.

[0031] Methods for waste plastic separation, as well as facilities and systems for processing particulate plastic solids obtained from waste plastic separation systems are generally described herein. Figure 1 As depicted in , in one embodiment or in combination with any of the mentioned embodiments, the method generally includes separating mixed plastic waste (MPW) 10 into a polyethylene terephthalate (PET) rich stream 20 and a PET depleted stream 30.

[0032] In one embodiment or in combination with any of the mentioned embodiments, the PET-rich stream 20 comprises at least two PET-rich streams, which may have the same or different compositions. Additionally, in one embodiment or in combination with any of the mentioned embodiments, the PET-depleted stream 30 comprises at least two PET-depleted streams.

[0033] In one embodiment or in combination with any of the above embodiments, the separation includes the use of one or more density separation stages. Although they comprise different compositions, each of the PET-rich stream 20 and the PET-depleted stream 30 comprises at least 90 wt% plastic material. Furthermore, the PET concentration in the PET-depleted stream 30 is lower than the PET concentration in the PET-rich stream 20, and the PET concentration in the PET-rich stream 20 is higher than the PET concentration in the PET-depleted stream 30.

[0034] Mixed plastic waste (MPW) can be provided in a variety of forms. For example, MPW can be in the form of whole products, pellets (e.g., crushed, granulated, fibrous plastic pellets), bundles (e.g., compressed and bundled whole products), unbundled items (i.e., not bundled or packaged), containers (e.g., boxes, sacks, trailers, railroad cars, loader buckets), stockpiles (e.g., on the concrete slabs of buildings), and / or physically conveyed loose materials (e.g., pellets on a conveyor belt) or pneumatically conveyed loose materials (e.g., pellets mixed with air in a conveyor pipe). MPW can be provided from a variety of sources, including, but not limited to, municipal recycling facilities or regeneration facilities, or other mechanical or chemical sorting or separation facilities, manufacturers or factories or commercial production facilities, or retailers or distributors or wholesalers with post-industrial and pre-consumer recyclables, directly from homes / businesses (i.e., unprocessed recyclables), landfills, or warehouses on or around docks or ships.

[0035] Plastics include any organic synthetic polymer that is solid at 25° C. and 1 atm. The polymer can be a thermoplastic or thermosetting polymer. The number average molecular weight of the polymer can be at least 300, or at least 500, or at least 1000, or at least 5,000, or at least 10,000, or at least 20,000, or at least 30,000, or at least 50,000, or at least 70,000, or at least 90,000, or at least 100,000, or at least 130,000. The weight average molecular weight of the polymer can be at least 300, or at least 500, or at least 1000, or at least 5,000, or at least 10,000, or at least 20,000, or at least 30,000, or at least 50,000, or at least 70,000, or at least 90,000, or at least 100,000, or at least 130,000, or at least 150,000, or at least 300,000.

[0036] In one embodiment or in combination with any of the recited embodiments, the polymer can have a number average molecular weight of at least 300, or at least 1000, or at least 5,000, or at least 10,000, or at least 50,000, or at least 130,000. The polymer can have a number average molecular weight of 300 to 500,000, or 1000 to 400,000, or 5,000 to 300,000, or 10,000 to 250,000, or 50,000 to 200,000, or 100,000 to 150,000. The polymer can have a weight average molecular weight of at least 300, or at least 1000, or at least 10,000, or at least 50,000, or at least 100,000, or at least 150,000, or at least 300,000. The weight average molecular weight of the polymer can be from 300 to 1,000,000, or from 1000 to 750,000, or from 10,000 to 600,000, or from 50,000 to 500,000, or from 100,000 to 450,000, or from 150,000 to 400,000, or from 300,000 to 350,000.

[0037] In one embodiment or in combination with any of the mentioned embodiments, the MPW comprises post-consumer and / or post-industrial (or pre-consumer) material.

[0038] In one embodiment or in combination with any of the mentioned embodiments, the MPW comprises one or more plastic solids described herein, which may be untreated or have undergone mechanical reduction and / or pretreatment.

[0039] Examples of plastics include those that are solid at 25°C and 1 atm. In one embodiment or in combination with any other embodiment, MPWs include, but are not limited to, plastic components such as polyesters, including those having repeating aromatic or cyclic units, such as those containing repeating terephthalate or naphthalate units, such as PET and PEN, or those containing repeating furanoate repeating units, and although within the definition of PET, it is also worth mentioning polyesters having repeating terephthalate units and one or more of the following residues or moieties: TMCD (2,2,4,4-tetramethyl-1,3-cyclobutanediol), CHDM (cyclohexanedimethanol), propylene glycol, or NPG (neopentyl glycol), isosorbide, isophthalic acid, 1,4-butanediol, 1,3-propylene glycol and / or diethylene glycol or combinations thereof, and aliphatic polyesters such as PLA, polyol Acids, polycaprolactone and polyethylene adipate; polyolefins (e.g., low density polyethylene, high density polyethylene, low density polypropylene, high density polypropylene, cross-linked polyethylene, amorphous polyolefins, and copolymers of any of the foregoing polyolefins), polyvinyl chloride (PVC), polystyrene, polytetrafluoroethylene, acrylonitrile butadiene styrene (ABS), celluloses, such as cellulose acetate, cellulose diacetate, cellulose triacetate, cellulose acetate propionate, cellulose acetate butyrate, and regenerated cellulose such as viscose; epoxides, polyamides, phenolic resins, polyacetals, polycarbonates, polyphenylene alloys, poly(methyl methacrylate), styrene-containing polymers, polyurethanes, vinyl polymers, styrene acrylonitrile, thermoplastic elastomers other than tires, and urea-containing polymers and melamine.

[0040] In one embodiment or in combination with any of the above embodiments, the MPW contains a thermosetting polymer. Examples of the amount of thermosetting polymer present in the MPW can be at least 1 wt%, or at least 2 wt%, or at least 5 wt%, or at least 10 wt%, or at least 15 wt%, or at least 20 wt%, or at least 25 wt%, or at least 30 wt%, or at least 40 wt%, based on the weight of the MPW. The amount of thermosetting polymer present in the MPW can be at least 1 wt%, or at least 10 wt%, or at least 20 wt%, or at least 40 wt%, based on the weight of the MPW. The amount of thermosetting polymer present in the MPW can be from 1 wt% to 80 wt%, or from 10 wt% to 70 wt%, or from 20 wt% to 60 wt%, or from 40 wt% to 50 wt%, based on the weight of the MPW.

[0041] In one embodiment or combination with any of the mentioned embodiments, the MPW contains a plastic, at least a portion of which is obtained from cellulose, such as a cellulose derivative having a degree of acyl substitution of less than 3, or from 1.8 to 2.8, such as cellulose acetate, cellulose diacetate, cellulose triacetate, cellulose acetate propionate, cellulose acetate butyrate.

[0042] In one embodiment or in combination with any of the mentioned embodiments, the MPW contains a plastic, at least a portion of which is obtained from a polymer having repeating terephthalate units, such as polyethylene terephthalate, polypropylene terephthalate, polybutylene terephthalate, and copolyesters thereof.

[0043] In one embodiment or combination with any of the mentioned embodiments, the MPW contains a plastic at least a portion of which is derived from a copolyester having a plurality of dicyclohexanedimethanol moieties, 2,2,4,4-tetramethyl-1,3-cyclobutanediol moieties, or a combination thereof.

[0044] In one embodiment or in combination with any of the mentioned embodiments, the MPW contains a plastic at least a portion of which is derived from low density polyethylene, high density polyethylene, linear low density polyethylene, polypropylene, polymethylpentene, polybutene-1, and copolymers thereof.

[0045] In one embodiment or in combination with any of the mentioned embodiments, the MPW contains plastic, at least a portion of which is obtained from eyeglass frames or cross-linked polyethylene.

[0046] In one embodiment or in combination with any of the mentioned embodiments, the MPW contains plastic, at least a portion of which is obtained from plastic bottles.

[0047] In one embodiment or in combination with any of the mentioned embodiments, the MPW contains plastic, at least a portion of which is obtained from diapers.

[0048] In one embodiment or in combination with any of the mentioned embodiments, the MPW contains plastic, at least a portion of which is obtained from polystyrene foam or expanded polystyrene.

[0049] In one embodiment or in combination with any of the mentioned embodiments, the MPW contains plastic, at least a portion of which is obtained from flash spun high density polyethylene.

[0050] In one embodiment or in combination with any of the aforementioned embodiments, the MPW contains plastic having or obtained from a plastic having resin ID codes 1-7 within the chasing arrow triangle established by SPI. In one embodiment or in combination with any of the aforementioned embodiments, at least a portion of the MPW contains one or more plastics that are not typically mechanically recycled. These include plastics having numbers 3 (polyvinyl chloride), 5 (polypropylene), 6 (polystyrene), and 7 (other). In one embodiment or in combination with any of the mentioned embodiments, the MPW comprises at least 0.1 wt%, or at least 0.5 wt%, or at least 1 wt%, or at least 2 wt%, or at least 3 wt%, or at least 5 wt%, or at least 7 wt%, or at least 10 wt%, or at least 12 wt%, or at least 15 wt%, or at least 20 wt%, or at least 25 wt%, or at least 30 wt%, or at least 40 wt%, or at least 50 wt%, or at least 65 wt%, or at least 85 wt%, or at least 90 wt% of plastic having or corresponding to number 3, 5, 6, 7, or a combination thereof, based on the weight of the plastic in the MPW. The MPW may comprise a plastic having or obtained from a plastic having 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 wt % of at least one, at least two, at least three, or at least four different kinds of resin ID codes.

[0051] In one embodiment or in combination with any of the embodiments mentioned, the MPW comprises at least 0.1 wt%, or at least 1 wt%, or at least 10 wt%, or at least 25 wt%, or at least 50 wt%, or at least 90 wt% of plastics having or corresponding to numbers 3, 5, 6, 7, or a combination thereof, based on the weight of the plastics in the MPW. The MPW may contain 0.1 wt%-99.9 wt%, or 1 wt%-99 wt%, or 10 wt%-98 wt%, or 25 wt%-97 wt%, or 50 wt%-95 wt%, or 90 wt%-93 wt% of plastics having or corresponding to numbers 3, 5, 6, 7, or a combination thereof, based on the weight of the plastics in the MPW. The MPW may comprise a plastic having or obtained from a plastic having at least 30, at least 50, at least 70, at least 90, at least 95, or at least 99 wt% of at least one, at least two, at least three, or at least four different types of resin ID codes. The MPW may comprise a plastic having or derived from a plastic having 30-99 wt%, or 50-98 wt%, or 70-97 wt%, or 90-95 wt% of one to four, or two to three different kinds of resin ID codes.

[0052] In one embodiment or in combination with any of the embodiments mentioned, the combination of PET and the polyolefin comprises at least 50, at least 75, at least 90, at least 95, or at least 99 wt% of the MPW, based on a dry plastic basis. PET can comprise at least 5, at least 10, at least 20, at least 30, at least 40, at least 50, at least 75, at least 90, or at least 95 wt% of the MPW, based on a dry plastic basis. PVC can comprise at least 0.001, at least 0.01, at least 0.05, at least 0.1, or at least 0.25 wt% and / or no more than 5, no more than 4, no more than 3, no more than 2, no more than 1, no more than 0.75, or no more than 0.5 wt% of the MPW. PET and PVC can be combined in any of these amounts relative to the weight of the MPW.

[0053] In one embodiment or in combination with any of the mentioned embodiments, the combination of PET and the polyolefin comprises at least 50, at least 75, at least 90, at least 95, or at least 99 wt% of the MPW, based on a dry plastic basis. The combination of PET and the polyolefin may comprise 50 wt%-99.9 wt%, or 75 wt%-99 wt%, or 90 wt%-95 wt% of the MPW, based on a dry plastic basis. PET may comprise at least 5, or at least 20, or at least 50, or at least 75, or at least 90 wt% of the MPW, based on a dry plastic basis. PET may comprise 5 wt%-99 wt%, or 20 wt%-98 wt%, or 50 wt%-97 wt%, or 75 wt%-96 wt%, or 90 wt%-95 wt% of the MPW, based on a dry plastic basis. PVC may constitute 0.001 wt%-5 wt%, or 0.01 wt%-3 wt%, or 0.05 wt%-2 wt%, or 0.1 wt%-1 wt%, or 0.25 wt%-0.75 wt% of the MPW. PET and PVC may be combined in any of these mentioned amounts relative to the weight of the MPW.

[0054] In one embodiment or in combination with any of the embodiments mentioned, the MPW comprises a multicomponent polymer. As used herein, the term "multicomponent polymer" refers to an article and / or particle comprising at least one synthetic or natural polymer combined, attached, or otherwise physically and / or chemically associated with at least one other polymer and / or non-polymeric solid. The polymer can be a synthetic polymer or plastic, such as PET, olefin, and / or nylon. The non-polymeric solid can be a metal, such as aluminum. The multicomponent polymer can include a metallized plastic. In one embodiment or in combination with any of the embodiments mentioned, the MPW comprises a multicomponent plastic in the form of a multilayer polymer. As used herein, the term "multilayer polymer" refers to a multicomponent polymer comprising PET and at least one other polymer and / or non-polymeric solid, which are physically and / or chemically associated together in two or more physically distinct layers. A polymer or plastic is considered a multilayer polymer even if a transition zone may exist between two layers, such as in an adhesive layer or coextruded layer. An adhesive between two layers is not considered a layer. A multilayer polymer may include a layer comprising PET and one or more additional layers, wherein at least one additional layer is a synthetic or natural polymer other than PET, or a polymer that does not contain repeating units of ethylene terephthalate, or a polymer that does not contain repeating units of an alkylene terephthalate (a "non-PET polymer layer"), or other non-polymeric solid. Examples of non-PET polymer layers include nylon, polylactic acid, polyolefins, polycarbonate, ethylene vinyl alcohol, polyvinyl alcohol, and / or other plastics or plastic films associated with PET-containing articles and / or pellets, as well as natural polymers such as whey protein. A multilayer polymer may include a metal layer, such as aluminum, provided that at least one additional polymer layer other than the PET layer is present. The layers may be adhered using adhesives or other methods, physically adjacent (i.e., the article is pressed against the film), tackified (i.e., the plastics are heated and bonded together), coextruded plastic films, or otherwise attached to the PET-containing article. A multilayer polymer may include a PET film associated with an article containing other plastics in the same or similar manner. The MPW can comprise a multicomponent polymer in the form of PET and at least one other plastic, such as a polyolefin (e.g., polypropylene) and / or other synthetic or natural polymer, combined in a single physical phase. For example, the MPW comprises a heterogeneous mixture comprising a compatibilizer, PET, and at least one other synthetic or natural polymer plastic (e.g., a non-PET plastic) combined in a single physical phase. As used herein, the term "compatibilizer" refers to an agent that is capable of combining at least two otherwise immiscible polymers in a physical mixture (i.e., a blend).

[0055] In one embodiment or in combination with any of the embodiments, the MPW comprises no more than 20, no more than 10, no more than 5, no more than 2, no more than 1, or no more than 0.1 wt% nylon, based on a dry plastic basis. The MPW may comprise 0.01 wt%-20 wt%, 0.05 wt%-10 wt%, 0.1 wt%-5 wt%, or 1 wt%-2 wt% nylon, based on a dry plastic basis. The MPW may comprise no more than 40, no more than 20, no more than 10, no more than 5, no more than 2, or no more than 1 wt% multicomponent polymer, based on a dry plastic basis. The MPW may comprise 0.1 wt%-40 wt%, 1 wt%-20 wt%, or 2 wt%-10 wt% multicomponent polymer, based on a dry plastic basis. The MPW may comprise no more than 40, no more than 20, no more than 10, no more than 5, no more than 2, or no more than 1 wt% multilayer polymer, based on a dry plastic basis. The MPW may comprise, based on a dry plastic basis, 0.1 wt% to 40 wt%, 1 wt% to 20 wt%, or 2 wt% to 10 wt% of the multi-stage polymer.

[0056] In one embodiment or in combination with any of the embodiments mentioned, the non-plastic solids constitute at least 0.1, at least 1, at least 2, at least 4, or at least 6 wt% of the MPW, and / or no more than 25, no more than 15, no more than 10, no more than 5, or no more than 2.5 wt% of the MPW. The non-plastic solids may constitute 0.1 wt%-25 wt%, or 1 wt%-15 wt%, or 2 wt%-10 wt% of the MPW. The non-plastic solids may include inert fillers (e.g., calcium carbonate, hydrated aluminum silicate, alumina trihydrate, calcium sulfate), metals, rocks, sand, glass, additives (e.g., thixotropes, pigments and colorants, flame retardants, explosion suppressants, UV inhibitors and stabilizers, conductive metals or carbon, release agents such as zinc stearate, waxes, and silicones), etc.

[0057] The non-plastic solids may also include cellulosic material, such as cellulosic fiber material from cardboard. In one embodiment or in combination with any of the mentioned embodiments, the cellulosic material constitutes at least 0.01, at least 0.1, at least 0.2, or at least 0.5 wt% of the MPW and / or no more than 20, no more than 15, no more than 12, or no more than 10 wt% of the MPW. The cellulosic material may constitute 0.01 wt%-20 wt%, 0.1 wt%-15 wt%, 0.5 wt%-10 wt%, or 1 wt%-5 wt% of the MPW. Such cellulosic material may interfere with the separation of plastic particles, for example, in the density separation process described below. Therefore, before feeding the MPW to the plastic separation process described herein, a friction scrubber or other process may be used to remove cardboard and / or other cellulosic material from the MPW.

[0058] In one embodiment or in combination with any of the mentioned embodiments, the liquid constitutes at least 0.01, at least 0.1, at least 0.5, or at least 1 wt% of the MPW and / or no more than 25, no more than 10, no more than 5, or no more than 2.5 wt% of the MPW. The liquid may constitute 0.01-25 wt%, 0.1-10 wt%, 0.5-5 wt%, or 1-2.5 wt% of the MPW.

[0059] MPW may comprise recycled (post-consumer or post-industrial (or pre-consumer)) textiles. Textiles may contain natural and / or synthetic fibers, rovings, yarns, nonwoven webs, cloths, fabrics and products made from or containing any of the foregoing. Textiles may be woven, knitted, knotted, stitched, tufted, pressed together (e.g., as in a felting operation), embroidered, lace, crocheted, braided or nonwoven webs and materials. Textiles as used herein include fabrics and fibers separated from textiles or other products containing fibers, discarded or off-spec fibers or yarns or fabrics, or any other source of loose fibers and yarns. Textiles also include staple fibers, continuous fibers, threads, tows, twisted and / or spun yarns, greige fabrics made from yarns, finished fabrics made by wet processing greige fabrics, and garments made from finished fabrics or any other fabrics. Textiles include apparel, upholstery, and industrial types of textiles. Textiles also include post-industrial textiles or post-consumer textiles or both.

[0060] Examples of textiles in the apparel category (things worn by humans or made for the body) include sport coats, suits, trousers and casual or work pants, shirts, socks, sportswear, dresses, undergarments, outerwear such as raincoats, cold-weather jackets and coats, sweaters, protective clothing, uniforms, and accessories such as scarves, hats, and gloves. Examples of textiles in the interior decoration category include furniture upholstery and sofa coverings, carpets and rugs, curtains, bedding such as sheets, pillowcases, duvets, quilts, mattress covers; linens, tablecloths, towels, face cloths, and blankets. Examples of industrial textiles include transportation (car, plane, train, bus) seats, floor mats, trunk linings, and roof linings; outdoor furniture and cushions, tents, backpacks, luggage, ropes, conveyor belts, calender roller felts, polishing cloths, rags, soil erosion fabrics and geotextiles, agricultural mats and screens, personal protective equipment, bulletproof vests, medical bandages, sutures, tapes, etc.

[0061] The nonwoven web that is classified as textile does not include the classification of wet-laid nonwoven web and the goods made therefrom. Although the various goods with the same function can be made by dry-laid or wet-laid methods, the goods made by dry-laid nonwoven web are classified as textiles. The example of the suitable goods that can be formed by the dry-laid nonwoven web described herein can include those for the end-uses of individual, consumer, industry, food service, medical treatment and other types. Specific example can include but is not limited to baby wipes, flushable wet wipes, disposable diapers, training pants, feminine hygiene products such as sanitary towels and tampons, adult incontinence pads, underwear or underpants and pet training pads. Other examples include various dry or wet wipes, including those for consumer (such as personal care or family) and industrial (such as food service, health care or professional) purposes. Nonwoven web also can be used as the filler of pillows, mattresses and interior decoration, the cotton batting of quilts and quilts. In medical and industrial fields, nonwoven web of the present invention can be used for medical face mask and industrial face mask, protective clothing, hat and shoe cover, disposable bed sheet, surgical gown, curtain, bandage and medical dressing.Additionally, nonwoven web described herein can be used for environmental fabric, such as geotextile and tarpaulin, oil absorption pad and chemical absorption pad, and building materials, such as sound insulation or heat insulation, tent, timber and soil covering and sheet material.Nonwoven web can also be used for other consumer end uses, such as packaging, heat insulation or sound insulation and various types of clothing for carpet backing, consumer goods, industrial products and agricultural products.Dry-laid nonwoven web as described herein can also be used for various filtering applications, including transportation (such as, automobile or aviation), business, residence, industry or other professional applications.Example can include the filter element for consumer or industrial air or liquid filter (such as, gasoline, oil, water), including the nanofiber web for microfiltration, and end uses such as tea bag, coffee filter and drying paper. Furthermore, nonwoven webs as described herein may be used to form various parts for automobiles including, but not limited to, brake pads, trunk liners, carpet tufts, and floor mats.

[0062] Textiles can include a single type or multiple types of natural fibers and / or a single type or multiple types of synthetic fibers. Examples of textile fiber combinations include all natural, all synthetic, two or more types of natural fibers, two or more types of synthetic fibers, one type of natural fiber and one type of synthetic fiber, one type of natural fiber and two or more types of synthetic fibers, two or more types of natural fibers and one type of synthetic fiber, and two or more types of natural fibers and two or more types of synthetic fibers.

[0063] Natural fibers include those of plant or animal origin. Natural fibers can be cellulose, hemicellulose, and lignin. Examples of plant-derived natural fibers include hardwood pulp, softwood pulp, and wood flour; and other plant fibers, including those in wheat straw, rice straw, abaca, coconut fiber, cotton, flax, hemp, jute, bagasse, kapok, papyrus, ramie, rattan, grapevine, kenaf, abaca, henna, sisal, soybean, cereal straw, bamboo, reed, esparto grass, bagasse, Indian grass, milkweed fluff fiber, pineapple leaf fiber, switchgrass, lignin-containing plants, etc. Examples of animal-derived fibers include wool, silk, mohair, cashmere, goat hair, horse hair, fowl fiber, camel hair, angora wool, and alpaca hair.

[0064] Synthetic fibers are those fibers that are synthesized or derived, or regenerated, at least in part, by a chemical reaction and include, but are not limited to, rayon, viscose, mercerized fibers or other types of regenerated cellulose (natural cellulose converted to a soluble cellulose derivative and then regenerated), such as lyocell (also known as Tencel), cupro (CuPro), Modal, acetates such as polyvinyl acetate, polyamides including nylon, polyesters such as PET, olefin polymers such as polypropylene and polyethylene, polycarbonates, polysulfates, polysulfones, polyethers such as the polyether-ureas known as spandex or elastane, polyacrylates, acrylonitrile copolymers, polyvinyl chloride (PVC), polylactic acid, polyglycolic acid, sulfopolyester fibers, and combinations thereof.

[0065] The textile may be in any of the forms mentioned above, for example, by reducing the textile raw material by chopping, shredding, raking, grinding, crushing or cutting to produce a reduced-diameter textile. The textile may also be densified. Examples of densification methods include those in which heat generated by friction or extrusion of particles, or other external heat, is applied to the textile to melt part or all of the textile, thereby causing the textile to agglomerate.

[0066] In one embodiment or in combination with any of the mentioned embodiments, the amount of textile (including textile fibers) in the MPW is at least 0.1 wt%, or at least 0.5 wt%, or at least 1 wt%, or at least 2 wt%, or at least 5 wt%, or at least 8 wt%, or at least 10 wt%, or at least 15 wt%, or at least 20 wt% of material obtained from textiles or textile fibers, based on the weight of the MPW. The amount of textile (including textile fibers) in the MPW can be no more than 50, no more than 40, no more than 30, no more than 20, no more than 15, no more than 10, no more than 8, no more than 5, no more than 2, no more than 1, no more than 0.5, no more than 0.1, no more than 0.05, no more than 0.01 or no more than 0.001 wt%, based on the weight of the MPW.

[0067] In one embodiment or in combination with any of the above embodiments, the amount of textile (including textile fibers) in the MPW is at least 0.1 wt%, or at least 1 wt%, or at least 5 wt%, or at least 10 wt%, or at least 20 wt% of the material obtained from the textile or textile fiber, based on the weight of the MPW. The amount of textile (including textile fibers) in the MPW can be 0.1 wt%-50 wt%, or 1 wt%-40 wt%, or 5 wt%-35 wt%, or 10 wt%-30 wt%, or 20 wt%-25 wt% of the material obtained from the textile or textile fiber, based on the weight of the MPW.

[0068] In one embodiment or in combination with any of the mentioned embodiments, the MPW is provided as a waste stream from another processing facility (e.g., a municipal recycling facility or a reclaiming facility). The MPW may comprise an MRF or reclaiming waste stream comprising at least 20, at least 30, at least 40, at least 50, at least 60, at least 70, at least 80, or at least 90 wt% PET and / or no more than 99, no more than 98, no more than 97, no more than 96, or no more than 95 wt% PET on a dry plastic basis. The MPW may comprise an MRF or reclaiming waste stream comprising 20-99 wt%, 50-98 wt%, 75-97 wt%, or 90-95 wt% PET.

[0069] In one embodiment or combination with any of the mentioned embodiments, the MPW comprises a colored PET waste stream comprising 50 wt%-90 wt% PET on a dry plastic basis. In one embodiment or combination with any of the mentioned embodiments, the MPW comprises a wet fines waste stream comprising 25 wt%-75 wt% PET on a dry plastic basis. In one embodiment or combination with any of the mentioned embodiments, the MPW comprises an eddy (metal) waste stream comprising 80 wt%-98 wt% PET on a dry plastic basis. In one embodiment or combination with any of the mentioned embodiments, the MPW comprises a flake waste stream comprising 40 wt%-80 wt% PET on a dry plastic basis. In one embodiment or combination with any of the mentioned embodiments, the MPW comprises a plastic dust waste stream comprising 95 wt%-99 wt% PET on a dry plastic basis.

[0070] The MPW feedstock to the separation process described herein, particularly to the first density separation stage of such embodiments, can comprise unprocessed MPW, or MPW that has been unpacked, subjected to size reduction (e.g., to form MPW pellets), or otherwise processed or pre-processed. Regardless, the MPW feedstock to the separation process, particularly to the first density separation stage, can comprise the aforementioned amounts of plastic and non-plastic components. However, in one embodiment or in combination with any of the aforementioned embodiments, the MPW feedstock to the separation process, particularly to the first density separation stage, can comprise relatively small amounts of or be absent of one or more specific components, as described below.

[0071] In one embodiment or in combination with any of the embodiments mentioned, the MPW feedstock comprises no more than 20, no more than 15, no more than 12, no more than 10, no more than 8, no more than 6, no more than 5, no more than 4, no more than 3, no more than 2, or no more than 1 wt% biowaste material, with the total weight of the MPW feedstock taken as 100 wt% on a dry basis. The MPW feedstock can comprise 0.01 wt%-20 wt%, 0.1 wt%-10 wt%, 0.2 wt%-5 wt%, or 0.5 wt%-1 wt% biowaste material, with the total weight of the MPW feedstock taken as 100 wt% on a dry basis. As used herein, the term "biowaste" refers to material derived from living organisms or organic sources. Exemplary biowaste materials include, but are not limited to, cotton, wood, sawdust, food scraps, animals and animal parts, plants and plant parts, and fertilizers.

[0072] In one embodiment or in combination with any of the embodiments mentioned, the MPW feedstock comprises no more than 20, no more than 15, no more than 12, no more than 10, no more than 8, no more than 6, no more than 5, no more than 4, no more than 3, no more than 2, or no more than 1 wt% of manufactured cellulose products, with the total weight of the MPW feedstock taken as 100 wt% on a dry basis. The MPW feedstock may comprise 0.01 wt%-20 wt%, 0.1 wt%-10 wt%, 0.2 wt%-5 wt%, or 0.5 wt%-1 wt% of manufactured cellulose products, with the total weight of the MPW feedstock taken as 100 wt% on a dry basis. As used herein, the term "manufactured cellulose products" refers to non-natural (i.e., man-made or machine-made) articles containing cellulose fibers and their waste products. Exemplary manufactured cellulose products include, but are not limited to, paper and paperboard.

[0073] As described above, the MPW may contain non-plastic solids. In one embodiment or in combination with any of the aforementioned embodiments, a separate separation process for removing non-plastic solids from the MPW is not required or included. However, in one embodiment or in combination with any of the aforementioned embodiments, at least a portion of the non-plastic solids in the MPW may be separated before the MPW feedstock is fed to the separation process(es), and in particular, to the first density separation stage. In any event, the MPW feedstock may contain no more than 20, no more than 15, no more than 12, no more than 10, no more than 8, no more than 6, no more than 5, no more than 4, no more than 3, no more than 2, or no more than 1 wt% of non-plastic solids, with the total weight of the MPW feedstock taken as 100 wt% on a dry basis. The MPW feedstock may contain 0.01 wt%-20 wt%, 0.1 wt%-10 wt%, 0.2 wt%-5 wt%, or 0.5 wt%-1 wt% of non-plastic solids, with the total weight of the MPW feedstock taken as 100 wt% on a dry basis.

[0074] After separation, the PET-rich stream 20 typically comprises at least 70, at least 80, at least 90, at least 95, or at least 99 wt% PET on a dry basis. In one embodiment or combination with any of the mentioned embodiments, the PET-rich stream 20 comprises 70 wt% to 99.9 wt%, 80 wt% to 99 wt%, or 90 wt% to 98 wt% PET on a dry basis.

[0075] In one embodiment or in combination with any of the mentioned embodiments, the PET enriched stream 20 is enriched in PET concentration on an undiluted solids dry basis relative to the PET concentration in the MPW stream 10 or the PET depleted stream 30, or both. For example, if the PET enriched stream 20 is diluted with a liquid or other solid after separation, the enrichment would be based on the concentration in the undiluted PET enriched stream and on a dry basis. The percent PET enrichment of the PET-enriched stream 20 relative to the MPW stream 10, the PET-depleted stream 30, or both, may be at least 10%, at least 20%, at least 40%, at least 50%, at least 60%, at least 80%, at least 100%, at least 125%, at least 150%, at least 175%, at least 200%, at least 225%, at least 250%, at least 300%, at least 350%, at least 400%, at least 500%, at least 600%, at least 700%, at least 800%, at least 900%, or at least 1000%, as determined by the formula:

[0076]

[0077] and

[0078]

[0079] wherein PETe is the concentration of PET in the PET-enriched stream 20 on an undiluted dry basis; and

[0080] PETm is the concentration of PET in the MPW stream 10 on a dry basis; and PETd is the concentration of PET in the PET-depleted stream 30 on a dry basis.

[0081] In one embodiment or in combination with any of the mentioned embodiments, the PET-rich stream 20 has a PET enrichment percentage of at least 10%, at least 100%, at least 200%, at least 300%, at least 500%, or at least 1000% relative to the MPW stream 10, the PET-depleted stream 30, or both, as determined by the above formula. The PET-rich stream 20 can have a PET enrichment percentage of 10%-100,000%, 100%-50,000%, 200%-40,000%, 300%-30,000%, 500%-20,000%, or 1000%-10,000% relative to the MPW stream 10, the PET-depleted stream 30, or both, as determined by the above formula.

[0082] In one embodiment or in combination with any of the mentioned embodiments, the PET-enriched stream 20 is further enriched in halogens, such as fluorine (F), chlorine (Cl), bromine (Br), iodine (I), and astatine (At), and / or halogen-containing compounds, such as PVC, relative to the concentration of halogens in the MPW stream 10, the PET-depleted stream 30, or both. The percent enrichment of the PET-enriched stream 20 in PVC relative to the MPW stream 10 can be at least 1%, at least 3%, at least 5%, at least 7%, at least 10%, at least 15%, at least 20%, at least 40%, at least 50%, at least 60%, at least 80%, at least 100%, at least 125%, at least 150%, at least 175%, at least 200%, at least 225%, at least 250%, at least 300%, at least 350%, at least 400%, or at least 500%, as determined by the following formula:

[0083]

[0084] and

[0085]

[0086] wherein PVCe is the concentration of PVC in the PET enriched stream 20 on an undiluted dry basis; and

[0087] PVCm is the concentration of PVC in the MPW stream 10 on an undiluted dry basis, and

[0088] where PVCd is the concentration of PVC in the PET depleted stream 30 on an undiluted dry basis.

[0089] In one embodiment or in combination with any of the mentioned embodiments, the PET-enriched stream 20 has a PVC enrichment percentage of at least 1%, at least 10%, at least 50%, at least 100%, at least 200%, at least 300%, at least 400%, or at least 500%, relative to the MPW stream 10, as determined by the above formula. The PET-enriched stream 20 can have a PVC enrichment percentage of 1%-50,000%, 10%-40,000%, 50%-30,000%, 100%-20,000%, 200%-15,000%, 300%-10,000%, 400%-5,000%, or 500%-1,000%, relative to the MPW stream 10, as determined by the above formula.

[0090] In one embodiment or in combination with any of the embodiments mentioned, the PET enriched stream 20 comprises at least 0.1, at least 0.5, at least 1, or at least 2, and / or no more than 10, no more than 8, or no more than 6, halogens and / or halogen-containing compounds on a dry basis. The PET enriched stream 20 may comprise 0.1 wt% to 10 wt%, 0.5 wt% to 8 wt%, 1 wt% to 6 wt%, or 2 wt% to 5 wt% halogens and / or halogen-containing compounds on a dry basis. However, it should be understood that the halogen concentration in the PET enriched stream (and the PET depleted stream) is based at least in part on the halogen content of the MPW feedstock, and thus even lower amounts of halogen may be present in the PET enriched stream. The PET enriched stream 20 may comprise no more than 1000 ppm, no more than 500 ppm, no more than 100 ppm, no more than 50 ppm, no more than 15 ppm, no more than 10 ppm, no more than 5 ppm, or no more than 1 ppm of halogens and / or halogen-containing compounds on a dry basis.

[0091] As described herein, plastic separation can be achieved using one or more density separation stages. Due to the overlap in density between typical PET plastics (approximately 1.27-1.40 g / cc) and typical PVC plastics (1.15-1.7 g / cc), the density separation process will typically result in a certain amount of PVC remaining in the same stream as the PET plastic after the separation process. Thus, in one embodiment or in combination with any of the aforementioned embodiments, the PVC component of the MPW 10 is not separated into a PVC-rich stream separate from the PET-rich stream 20. In one embodiment or in combination with any of the aforementioned embodiments, at least 50 wt% of the PVC component of the MPW 10 is separated from the MPW along with the PET in the PET-rich stream 20. On a dry basis, the PET-rich stream 20 can comprise at least 0.1, at least 0.5, at least 1, or at least 2, and / or no more than 10, no more than 8, or no more than 6 wt% PVC. On a dry basis, the PET-rich stream 20 may contain from 0.1 wt% to 10 wt%, from 0.5 wt% to 8 wt%, or from 1 wt% to 6 wt%, or from 2 wt% to 5 wt% PVC.

[0092] In one embodiment or combination with any of the mentioned embodiments, the PVC component of the PET rich stream 20 is not separated from the PET rich stream 20 prior to treating the PET polymer of the PET rich stream 20 in a downstream chemical recovery process. For example, at least 50, at least 60, at least 70, at least 80, at least 90, at least 95, at least 98, at least 99, or at least 100 wt% of the PVC in the PET rich stream 20 can remain in the PET rich stream 20 after treating the PET polymer in the PET rich stream 20 in the downstream chemical recovery process. In one embodiment or combination with any of the mentioned embodiments, at least 50, at least 75, at least 90, at least 95, at least 99, or at least 100 wt% of the PVC in the PET rich stream 20 remains in the PET rich stream 20 after treating the PET polymer in the PET rich stream 20 in the downstream chemical recovery process. In one embodiment or in combination with any of the mentioned embodiments, after treating the PET polymer in the PET rich stream 20 in a downstream chemical recovery process, 50 wt%-100 wt%, or 75 wt%-99 wt%, or 90 wt%-95 wt% of the PVC in the PET rich stream 20 remains in the PET rich stream 20.

[0093] In another example, less than 50, less than 40, less than 30, less than 20, less than 10, less than 5, less than 3, less than 2, less than 1, less than 0.5, or less than 0.1 wt% of PVC in the PET rich stream 20 can be separated from the PET rich stream 20 prior to processing the PET polymer in the PET rich stream 20. In one embodiment or combination with any of the mentioned embodiments, less than 50, less than 25, less than 10, less than 5, less than 1, or less than 0.1 wt% of PVC in the PET rich stream 20 is separated from the PET rich stream 20 prior to processing the PET polymer in the PET rich stream 20. In one embodiment or combination with any of the mentioned embodiments, 0.001 wt%-50 wt%, 0.01 wt%-25 wt%, 0.1 wt%-10 wt%, 0.5 wt%-5 wt%, or 1 wt%-2 wt% of PVC in the PET rich stream 20 is separated from the PET rich stream 20 prior to processing the PET polymer in the PET rich stream 20. A PET-rich stream that is also rich in PVC may be mixed with a separate PET-rich stream having a lower concentration of PVC than that in the PET-rich stream, thereby diluting the concentration of PVC in the initial PET-rich stream.

[0094] The density separation methods described herein are capable of separating and removing heavier (more dense) and lighter (less dense) plastics from a PET-rich stream 20. In one embodiment or in combination with any of the aforementioned embodiments, the PET-rich stream 20 is depleted in lighter plastic components, such as polyolefins, e.g., polyethylene, polypropylene, etc., which typically have a significantly lower density than PET and PVC and can therefore be separated from PET and PVC in one or more density separation stages. Similarly, the PET-rich stream 20 is typically depleted in heavier plastics, such as polytetrafluoroethylene, which has a higher density than PET and PVC. On a dry basis, the PET-rich stream 20 may contain no more than 50, no more than 40, no more than 30, no more than 20, no more than 10, no more than 5, or no more than 1 wt% polyolefins. On a dry basis, the PET-rich stream 20 may contain no more than 50, no more than 25, no more than 10, no more than 5, or no more than 1 wt% polyolefins. On a dry basis, the PET rich stream 20 may comprise 0.01 wt% to 50 wt%, 0.1 wt% to 25 wt%, 0.2 wt% to 10 wt%, 0.5 wt% to 5 wt%, or 1 wt% to 2 wt% polyolefin.

[0095] Additionally, other plastic and non-plastic components from MPW 10 can be separated from the PET (and PVC) by density separation or other separation methods. For example, in one embodiment or in combination with any of the above embodiments, the PET-rich stream 20 contains no more than 2, no more than 1, no more than 0.5, or no more than 0.1 wt% of a binder on a dry basis. The PET-rich stream 20 can contain 0.001 wt% to 2 wt%, 0.01 wt% to 1 wt%, or 0.1 wt% to 0.5 wt% of a binder on a dry basis. Typical binders include carpet glue, latex, styrene-butadiene rubber, and the like.

[0096] In one embodiment or in combination with any of the aforementioned embodiments, PET-rich stream 20 is depleted in nylon relative to PET-depleted stream 30. Nylons, or nylon polymers, are a family of synthetic polymers composed of polyamides (i.e., repeating units linked by amide chains) and are typically melt-processed in the form of fibers, films, or other shapes. The nylon content of a particular stream can typically be measured or represented by the nitrogen content of that stream. In each case, the nylon concentration of PET-rich stream 20 can be depleted by at least 10%, or at least 25%, or at least 40%, or at least 50%, or at least 60%, or at least 70%, or at least 80%, or at least 85%, or at least 90%, or at least 95%, or at least 97%, or at least 98%, relative to the nylon concentration in PET-depleted stream 30, based on the weight percentage of nitrogen atoms in the individual streams. Sampling methods can include randomly sampling from each stream, optionally taking two samples from each stream every 24 hours for two weeks, and drying to a moisture content of less than 10 wt%. The formula for this calculation is shown in Equation 1:

[0097]

[0098] in:

[0099] wt%N is the weight percentage of nitrogen atoms in the stream

[0100] dPET is the PET depleted stream and

[0101] ePET is a PET enriched stream

[0102] Using the same equation, substituting wt% NMPW (the weight percent of nitrogen atoms in the MPW stream) for wt% NePET in Equation 1, the PET-rich stream 20 can be depleted in nylon concentration relative to the MPW 10 stream by the same amount as described above.

[0103] In one embodiment or in combination with any of the embodiments mentioned, the PET-depleted stream 30 is enriched in nylon concentration relative to the PET-rich stream 20. In each case, the nylon concentration of the PET-depleted stream 30 can be enriched by at least 10%, or at least 25%, or at least 50%, or at least 75%, or at least 100%, or at least 150%, or at least 200%, or at least 250%, or at least 300%, or at least 350%, or at least 400%, or at least 450%, or at least 500%, or at least 600%, or at least 700%, or at least 800%, or at least 1000% relative to the nylon concentration in the PET-rich stream 20, calculated based on the weight percentage of nitrogen atoms in the individual streams. The sampling method can include randomly sampling from each stream, optionally taking two samples from each stream every 24 hours for two weeks. The formula for performing this calculation is according to Formula 2:

[0104]

[0105] in:

[0106] wt%N is the weight percentage of nitrogen atoms in the stream

[0107] dPET is the PET depleted stream and

[0108] ePET is a PET enriched stream

[0109] Using the same Equation 2, but replacing the wt% NePET in Equation 2 with wt% NMPW (the weight percentage of nitrogen atoms in the MPW stream), the PET-depleted stream 30 can be enriched in nylon concentration relative to the MPW 10 stream by at least 10%, or at least 25%, or at least 40%, or at least 50%, or at least 60%, or at least 70%, or at least 80%, or at least 85%, or at least 90%, in each case relative to the nylon concentration in the MPW 10 stream.

[0110] In one embodiment or combination with any of the mentioned embodiments, on a dry basis, the PET rich stream 20 comprises no more than 1, no more than 0.5, no more than 0.1, no more than 0.05, or no more than 0.03 wt% nylon. On a dry basis, the PET rich stream 20 can comprise from 0.001 wt% to 10 wt%, from 0.005 wt% to 5 wt%, or from 0.01 wt% to 1 wt%, or from 0.02 wt% to 0.1 wt% nylon.

[0111] In one embodiment or in combination with any of the mentioned embodiments, the PET-rich stream 20 is depleted in multi-layered polymers relative to the MPW 10, the PET-depleted stream 30, or both. On a dry basis, the PET-rich stream 20 can contain no more than 10, no more than 5, no more than 2, no more than 1, or no more than 0.1 wt% of the multi-layered polymers. On a dry basis, the PET-rich stream 20 can contain from 0.01 wt% to 10 wt%, from 0.05 wt% to 5 wt%, or from 0.1 wt% to 2 wt%, or from 0.5 wt% to 1 wt% of the multi-layered polymers.

[0112] In one embodiment or in combination with any of the mentioned embodiments, the PET-rich stream 20 is depleted in multicomponent polymer relative to the MPW 10, the PET-depleted stream 30, or both. On a dry basis, the PET-rich stream 20 can contain no more than 10, no more than 5, no more than 2, no more than 1, or no more than 0.1 wt% of the multicomponent polymer. On a dry basis, the PET-rich stream 20 can contain from 0.01 wt% to 10 wt%, from 0.05 wt% to 5 wt%, or from 0.1 wt% to 2 wt%, or from 0.5 wt% to 1 wt% of the multicomponent polymer.

[0113] Additionally, in one embodiment or in combination with any of the mentioned embodiments, the PET-rich stream 20 comprises no more than 4, no more than 3, no more than 2, no more than 1, no more than 0.5, or no more than 0.1 wt% plastic fillers and solid additives on a dry basis. The PET-rich stream 20 may comprise from 0.001 wt% to 4 wt%, from 0.01 wt% to 2 wt%, or from 0.1 wt% to 1 wt% plastic fillers and solid additives on a dry basis. Exemplary fillers and additives include silicon dioxide, calcium carbonate, talc, silica, glass, glass beads, alumina, and other solid inert materials that do not chemically react with the plastic or other components in the processes described herein.

[0114] In one embodiment or in combination with any of the mentioned embodiments, the PET rich stream 20 comprises no more than 2, no more than 1, no more than 0.5, no more than 0.2, or no more than 0.1 wt% cellulosic material. The PET rich stream 20 can comprise 0.001 wt% to 4 wt%, 0.01 wt% to 2 wt%, or 0.1 wt% to 1 wt% cellulosic material.

[0115] As described in greater detail below, in one embodiment or in combination with any of the aforementioned embodiments, the pretreatment steps (e.g., abrasive washing) and / or separation processes described herein are particularly effective in separating nylon from other polymeric or non-polymeric solids that are associated with PET in the form of multilayer polymers or other multi-component polymers. Regardless of the manner of association, the pretreatment and / or separation processes can effectively de-associate and separate the nylon and / or other polymeric and non-polymeric solids from the PET, thereby allowing for increased separation efficiency of these components. In one embodiment or in combination with any of the aforementioned embodiments, the PET-rich stream 20 comprises no more than 5, no more than 4, no more than 3, no more than 2, no more than 1, no more than 0.5, or no more than 0.1 wt% of associated PET-nylon on a dry basis. On a dry basis, the PET-rich stream 20 can comprise from 0.001 wt% to 5 wt%, from 0.01 wt% to 2 wt%, or from 0.1 wt% to 1 wt% of associated PET-nylon. On a dry basis, the PET-rich stream 20 may comprise no more than 20, no more than 15, no more than 10, no more than 5, no more than 2, or no more than 1 wt% of associated PET-nylon present in the MPW and / or the MPW feed stream fed to the first separation stage. On a dry basis, the PET-rich stream 20 may comprise from 0.01 wt% to 20 wt%, from 0.1 wt% to 10 wt%, or from 1 wt% to 5 wt% of associated PET-nylon present in the MPW and / or the MPW feed stream fed to the first separation stage.

[0116] The weight concentration of PET in the PET-depleted stream 30 is typically less than the concentration of PET in the PET-rich stream 20, or less than the concentration of PET in the MPW feed 10, or less than the concentration of PET in both the MPW feed 10 and the PET-rich stream 20, each on an undiluted dry basis. In one embodiment or in combination with any of the aforementioned embodiments, the PET-depleted stream 30 is also depleted in PVC relative to the PVC concentration in the PET-rich stream 20, or the PVC concentration in the MPW feed 10, or the PVC concentration in both the MPW feed 10 and the PET-rich stream 20. On a dry plastic basis, the PET-depleted stream may contain no more than 10, no more than 8, no more than 6, no more than 4, no more than 2, or no more than 1 wt% PVC. On a dry plastic basis, the PET-depleted stream may contain 0.01 wt% to 10 wt%, 0.1 wt% to 5 wt%, or 1 wt% to 2 wt% PVC.

[0117] Due to the separation of polyolefins from PET, PET-depleted stream 30 is enriched in polyolefins on an undiluted solids dry basis relative to the concentration of polyolefins in MPW feed 10, or PET-rich stream 20, or both. In one embodiment or combination with any of the recited embodiments, the percent enrichment of PET-depleted stream 30 in polyolefins relative to MPW stream 10, or relative to PET-rich stream 20, or both, is at least 10%, at least 20%, at least 40%, at least 50%, at least 60%, at least 80%, at least 100%, at least 125%, at least 150%, at least 175%, at least 200%, at least 225%, at least 250%, at least 300%, at least 350%, at least 400%, at least 500%, at least 600%, at least 700%, at least 800%, at least 900%, or at least 1000%, as determined by the formula:

[0118]

[0119] and

[0120]

[0121] wherein POd is the concentration of polyolefin in the PET-depleted stream 30 on an undiluted dry basis; and

[0122] POm is the concentration of PO in the MPW stream 10, on a dry basis, and

[0123] POe is the concentration of PO in the PET-rich stream 20.

[0124] In one embodiment or in combination with any of the mentioned embodiments, the polyolefin enrichment percentage of the PET-depleted stream 30 relative to the MPW stream 10, or relative to the PET-rich stream 20, or both, is at least 10%, at least 100%, at least 200%, at least 500%, or at least 1000%, as determined by the above formula. The polyolefin enrichment percentage of the PET-depleted stream 30 relative to the MPW stream 10, or relative to the PET-rich stream 20, or both, can be 10%-50,000%, 100%-40,000%, 200%-30,000%, 500%-20,000%, or 1000%-10,000%, as determined by the above formula.

[0125] In one embodiment or in combination with any other embodiment, the PET-depleted stream 30 is further depleted in halogens, such as fluorine (F), chlorine (Cl), bromine (Br), iodine (I), and astatine (At), and / or halogen-containing compounds, such as PVC, relative to the concentration of halogens in the MPW stream 10, the PET-rich stream 20, or both. The PET-depleted stream 30 can have a PVC depletion percentage of at least 1%, at least 3%, at least 5%, at least 7%, at least 10%, at least 15%, at least 20%, at least 25%, at least 30%, at least 35%, at least 40%, at least 50%, at least 60%, at least 65%, at least 70%, at least 75%, at least 80%, at least 85%, or at least 90%, relative to the MPW stream 10 or the PET-rich stream 20, as determined by the following formula:

[0126]

[0127] and

[0128]

[0129] where PVCm is the concentration of PVC in the MPW stream 10, on an undiluted dry basis;

[0130] PVCd is the concentration of PVC in the PET-depleted stream 30 on an undiluted dry basis; and

[0131] PVCe is the concentration of PVC in the PET-rich stream 20, on an undiluted dry weight basis.

[0132] In one embodiment or in combination with any of the mentioned embodiments, the PET-depleted stream 30 has a PVC depletion percentage of at least 1%, at least 10%, at least 25%, at least 50%, at least 75%, or at least 90% relative to the MPW stream 10 or the PET-rich stream 20, as determined by the above formula. The PET-depleted stream 30 can have a PVC depletion percentage of 1%-100%, 10%-99%, 25%-98%, 50%-97%, 75%-96%, or 90%-95% relative to the MPW stream 10 or the PET-rich stream 20, as determined by the above formula.

[0133] In one embodiment or in combination with any other embodiment, the PET-depleted stream 30 is also depleted in PET relative to the PET concentration in the MPW stream 10, the PET-rich stream 20, or both. The PET-depleted stream 30 may have a PET depletion percentage relative to the MPW stream 10 or the PET-rich stream 20 of at least 1%, at least 3%, at least 5%, at least 7%, at least 10%, at least 15%, at least 20%, at least 25%, at least 30%, at least 35%, at least 40%, at least 50%, at least 60%, at least 65%, at least 70%, at least 75%, at least 80%, at least 85%, or at least 90% as determined by the following formula:

[0134]

[0135] and

[0136]

[0137] where PETm is the concentration of PET in the MPW stream 10, on an undiluted dry basis;

[0138] PETd is the concentration of PET in the PET-depleted stream 30 on an undiluted dry basis; and

[0139] PETe is the concentration of PET in the PET-rich stream 20, on an undiluted dry weight basis.

[0140] In one embodiment or combination with any of the mentioned embodiments, the PET-depleted stream 30 has a PET depletion percentage of at least 1%, at least 10%, at least 25%, at least 50%, at least 75%, or at least 90% relative to the MPW stream 10 or the PET-rich stream 20, as determined by the above formula. The PET-depleted stream 30 can have a PET depletion percentage of 1%-100%, 10%-99%, 25%-98%, 50%-97%, 75%-96%, or 90%-95% relative to the MPW stream 10 or the PET-rich stream 20, as determined by the above formula.

[0141] The percentage of enrichment or depletion in any of the above embodiments can be averaged over a week, a three-day period, or a day, and can be measured to reasonably correlate a sample taken at the process outlet with the overall MPW in which the MPW sample resides, taking into account the residence time of the MPW flowing from the inlet to the outlet. For example, if the average residence time of the MPW is 2 minutes, then the outlet sample is taken two minutes after the input sample, allowing the samples to be correlated.

[0142] In one embodiment or combination with any of the mentioned embodiments, the PET-depleted stream 30 comprises at least 50, at least 60, at least 70, at least 80, at least 90, at least 95, or at least 98 wt% polyolefin on a dry plastic basis. The PET-depleted stream 30 may comprise at least 50, at least 75, at least 90, or at least 98 wt% polyolefin on a dry plastic basis. The PET-depleted stream 30 may comprise between 50 wt% and 100 wt%, between 75 wt% and 99 wt%, or between 90 wt% and 98 wt% polyolefin on a dry plastic basis.

[0143] In one embodiment or in combination with any of the aforementioned embodiments, PET-depleted stream 30 is enriched in nylon relative to MPW 10, PET-rich stream 20, or both. PET-depleted stream 30 can comprise at least 0.1, at least 0.5, at least 1, or at least 2 wt% nylon, and / or no more than 10, no more than 8, no more than 6, or no more than 4 wt% nylon, on a dry plastic basis. PET-depleted stream 30 can comprise 0.1 wt% to 10 wt%, 0.5 wt% to 8 wt%, 1 wt% to 6 wt%, or 2 wt% to 4 wt% nylon, on a dry plastic basis. The weight ratio of nylon in the PET-depleted stream to nylon in the PET-rich stream can be at least 1:1, at least 2:1, at least 5:1, at least 10:1, at least 50:1, or at least 100:1.

[0144] In one embodiment or in combination with any of the aforementioned embodiments, the PET-depleted stream 30 is enriched in multilayered polymer relative to the MPW 10, the PET-rich stream 20, or both. However, in one embodiment or in combination with any of the aforementioned embodiments, the PET-depleted stream 30 is depleted in multilayered polymer relative to the MPW 10. On a dry plastic basis, the PET-depleted stream 30 can comprise at least 0.001, at least 0.01, at least 0.1, or at least 1 wt% and / or no more than 10, no more than 8, no more than 6, or no more than 4 wt% of multilayered polymer. On a dry plastic basis, the PET-depleted stream 30 can comprise from 0.001 wt% to 10 wt%, from 0.01 wt% to 8 wt%, from 0.1 wt% to 6 wt%, or from 1 wt% to 4 wt% of multilayered polymer. The weight ratio of the multilayered polymer in the PET-depleted stream to the multilayered polymer in the PET-rich stream can be at least 1:1, at least 2:1, at least 5:1, at least 10:1, at least 50:1, or at least 100:1.

[0145] In one embodiment or in combination with any of the aforementioned embodiments, the PET-depleted stream 30 is enriched in multicomponent polymer relative to the MPW 10, the PET-rich stream 20, or both. However, in one embodiment or in combination with any of the aforementioned embodiments, the PET-depleted stream 30 is depleted in multicomponent polymer relative to the MPW 10. On a dry plastic basis, the PET-depleted stream 30 can comprise at least 0.001, at least 0.01, at least 0.1, or at least 1 wt% and / or no more than 10, no more than 8, no more than 6, or no more than 4 wt% of the multicomponent polymer. On a dry plastic basis, the PET-depleted stream 30 can comprise from 0.001 wt% to 10 wt%, from 0.01 wt% to 8 wt%, from 0.1 wt% to 6 wt%, or from 1 wt% to 4 wt% of the multicomponent polymer. The weight ratio of the multicomponent polymer in the PET-depleted stream to the multicomponent polymer in the PET-rich stream can be at least 1:1, at least 2:1, at least 5:1, at least 10:1, at least 50:1, or at least 100:1.

[0146] As described above, in one embodiment or in combination with any of the embodiments mentioned, separation includes at least one density separation stage. In one embodiment or in combination with any of the embodiments mentioned, separation includes at least two density separation stages (i.e., a first density separation stage and a second density separation stage). At least one density separation stage may include a float-sink density separation stage and / or a centrifugal density separation stage. The float-sink density separation stage refers to a tank, vessel or other suitable container for holding a liquid medium (e.g., water) that is capable of separating the components of a feed mixture based on the density differences of the components. Components with a density greater than that of the liquid medium sink to the bottom of the tank, while components with a density less than that of the liquid medium float on the surface of the liquid. Various mechanical methods can be used to recover the sinking components as a heavy or "high density" stream and the floating components as a light or "low density" stream.

[0147] In one embodiment or in combination with any of the embodiments mentioned, the liquid medium comprises water. Salt, sugars and / or other additives can be added to the liquid medium, for example, to increase the density of the liquid medium and adjust the target separation density of the float-sink separation stage. In one embodiment or in combination with any of the embodiments mentioned, the liquid medium comprises a concentrated brine solution. In one or more such embodiments, the salt is sodium chloride. However, in one or more other embodiments, the salt is a non-halogenated salt, such as acetate, carbonate, citrate, nitrate, nitrite, phosphate, sulfate and / or hydroxide. In one embodiment or in combination with any of the embodiments mentioned, the liquid medium comprises a concentrated brine solution comprising sodium bromide, sodium dihydrogen phosphate, sodium hydroxide, sodium iodide, sodium nitrate, sodium thiosulfate, potassium acetate, potassium bromide, potassium carbonate, potassium hydroxide, potassium iodide, calcium chloride, cesium chloride, ferric chloride, strontium chloride, zinc chloride, manganese sulfate, zinc sulfate and / or silver nitrate. In one embodiment or in combination with any of the embodiments mentioned, the salt is a caustic component. The pH value of the concentrated brine solution can be greater than 7, greater than 8, greater than 9 or greater than 10. In one embodiment or in combination with any of the mentioned embodiments, the salt comprises sodium hydroxide, potassium hydroxide and / or potassium carbonate. In one embodiment or in combination with any of the mentioned embodiments, the salt is potassium carbonate. Advantageously, when the concentrated brine comprises potassium carbonate and / or other caustic components (e.g., hydroxides such as sodium hydroxide and / or potassium hydroxide), the use of a separate caustic component to control pathogens and odors can be avoided. Therefore, in one embodiment or in combination with any of the mentioned embodiments, no separate caustic component is introduced into the density separation stage.

[0148] In one embodiment or in combination with any of the aforementioned embodiments, the liquid medium comprises a sugar, such as sucrose. In one embodiment or in combination with any of the aforementioned embodiments, the liquid medium comprises carbon tetrachloride, chloroform, dichlorobenzene, dimethyl sulfate, and / or trichloroethylene. The specific composition and concentration of the liquid medium can be selected based on the desired target separation density of the separation stage.

[0149] In one embodiment or in combination with any of the aforementioned embodiments, a centrifugal density separation stage refers to a device that utilizes eddy currents to separate components of a feed mixture based on differences in their densities. The device can be configured such that centrifugal acceleration causes less dense components to move toward a central core of the eddy currents, while denser components move away from the core. The centrifugal density separation stage can be a cyclone separator. The centrifugal density separation stage can be a hydrocyclone separator, which includes a liquid medium that separates components based on the ratio of its centripetal force to fluid resistance. Advantageously, as explained in more detail below, friction and / or caustic solution in the hydrocyclone can effectively decouple individual plastic components in the multilayer polymer material. Thus, the use of one or more hydrocyclones can improve the separation efficiency of PET from nylon and plastic film, as well as the separation efficiency of other plastics or non-plastics from PET film. This can have the effect of reducing the nylon and plastic film content in a PET-rich stream and / or reducing the PET content in a PET-depleted stream (e.g., an olefin-rich stream). The centrifugal density separation stage can use any of the same or different liquid media as described above for the float and sink stage, and may also include salts, sugars and / or other additives, for example to increase the density of the liquid medium and adjust the target separation density. The centrifugal density separation stage may include a vertical or angled / inclined device. Regardless of the embodiment, the centrifugal density separation stage can be configured so that the feed mixture is fed to an intermediate position, wherein one of the heavy or light streams is removed from a position above the feed and the other is removed from a position below the feed. The centrifugal density separation stage may include a center outlet for less dense materials, which is located at a position above the wall outlet for more dense materials.

[0150] An embodiment using at least two density separation stages is described below.

[0151] like Figure 2 As shown, in one embodiment or in combination with any of the embodiments mentioned, the waste plastic separation method includes at least two density separation stages 140, 150. In certain such embodiments, the method generally includes introducing mixed waste plastic (MPW) particles 110 into a first density separation stage 140 and feeding the output 142 from the first density separation stage 140 to a second density separation stage 150. The density separation stages 140, 150 can be any system or unit operation that performs a density separation process as defined herein. At least one of the density separation stages 140, 150 can include a centrifugal separation stage or a float-sink separation stage. Each of the first density separation stage 140 and the second density separation stage 150 can include a centrifugal separation stage and / or a float-sink separation stage.

[0152] To produce the PET-enriched material stream 120, one of the density separation stages 140, 150 typically comprises a low-density separation stage, while the other typically comprises a high-density separation stage. As defined herein, the target separation density of the low-density separation stage is less than the target separation density of the high-density separation stage. In one embodiment or combination with any of the aforementioned embodiments, the target separation density of the low-density separation stage is less than the density of PET, and the target separation density of the high-density separation stage is greater than the density of PET.

[0153] In one embodiment or in combination with any of the mentioned embodiments, the target separation density of the low density separation stage is less than 1.35, less than 1.34, less than 1.33, less than 1.32, less than 1.31 or less than 1.30 g / cc and / or at least 1.25, at least 1.26, at least 1.27, at least 1.28 or at least 1.29 g / cc.

[0154] In one embodiment or in combination with any of the aforementioned embodiments, the target separation density of the high density separation stage is at least 0.01, at least 0.025, at least 0.05, at least 0.075, at least 0.1, at least 0.15, or at least 0.2 g / cc greater than the target separation density of the low density separation stage. The target separation density of the high density separation stage can be 0.01 to 20, 0.025 to 18, 0.05 to 15, 0.075 to 12, 0.1 to 10, 0.15 to 5, or 0.2 to 1 g / cc greater than the target separation density of the low density separation stage.

[0155] In one embodiment or combination with any of the mentioned embodiments, the target separation density of the high density separation stage is at least 1.31, at least 1.32, at least 1.33, at least 1.34, at least 1.35, at least 1.36, at least 1.37, at least 1.38, at least 1.39 or at least 1.40 g / cc and / or no more than 1.45, no more than 1.44, no more than 1.43, no more than 1.42 or no more than 1.41 g / cc.

[0156] In one embodiment or in combination with any of the mentioned embodiments, the target separation density of the low density separation stage is in the range of 1.25 to 1.35, 1.26 to 1.34, 1.27 to 1.33, 1.28 to 1.32 or 1.29 to 1.31 g / cc, and / or the target separation density of the high density separation stage is in the range of 1.35 to 1.45, 1.36 to 1.44, 1.37 to 1.43, 1.38 to 1.42 or 1.39 to 1.41 g / cc.

[0157] It should be understood that the target separation density referred to herein refers to the density of the plastic used for separation, and not to the density of the concentrated salt solution used in the separation process, which may be the same as or different from the target separation density of the plastic material. For example, in a typical sink / float separation stage, the plastic and the concentrated salt solution densities are the same or substantially the same. However, in a typical hydrocyclone separation stage, the concentrated salt solution density generally does not exceed the target plastic density, but the concentrated salt solution density may be less than the target plastic density. Furthermore, it should be understood that if the process actually separates the plastic at a value within the claimed or specified target separation density value, then regardless of the intent and the density of the salt solution, the claimed or specified target separation density value or range is deemed to have been established or met.

[0158] In one embodiment or in combination with any of the aforementioned embodiments, the hydrocyclone is used with a concentrated brine solution having a liquid density typically between 0.95 and 1.45 g / cc. In one embodiment or in combination with any of the aforementioned embodiments, the hydrocyclone is used with a concentrated brine solution having a liquid density between 1.25 and 1.35 g / cc and a target plastic separation density of 1.25 to 1.35 g / cc. Such embodiments generally allow for higher PET purity, but result in significant yield losses. The hydrocyclone can also be used with a concentrated brine solution having a density between 0.95 and 1.20, or between 1.00 and 1.10 g / cc, and a target plastic separation density of 1.25 to 1.35 g / cc. Such embodiments will generally result in lower PET purity but higher PET yield. Therefore, when using one or more hydrocyclone density separators, the density of the concentrated brine solution can be selected, adjusted, or otherwise controlled based on the desired PET purity and / or yield specifications.

[0159] In one embodiment or in combination with any of the mentioned embodiments, at least one of the first 140 or second 150 density separation stages has a density separation efficiency with respect to PET of at least 90%, at least 95%, at least 98%, at least 99%, or at least 99.5%. The density separation efficiency of at least one of the first 140 or second 150 density separation stages with respect to PET may be between 90% and 99.9%, between 95% and 99.5%, or between 98% and 99%.

[0160] In one embodiment or in combination with any of the aforementioned embodiments, each of the first 140 and second 150 density separation stages has a density separation efficiency with respect to PET of at least 90%, at least 95%, at least 98%, at least 99%, or at least 99.5%. Each of the first 140 and second 150 density separation stages can have a density separation efficiency with respect to PET of 90%-99.9%, 95%-99.5%, or 98%-99%.

[0161] In one embodiment or in combination with any of the above embodiments, first density separation stage 140 is a low-density separation stage, and second density separation stage 150 is a high-density separation stage. First density separation stage 140 can produce a first PET-depleted stream 132, which is a polyolefin-rich stream, and a PET-enriched output stream 142, which is fed to second density separation stage 150. PET-enriched output stream 142 can also be PVC-enriched. First PET-depleted stream 132, which is a polyolefin-rich stream, can contain less than 10, less than 5, less than 1, less than 0.5, less than 0.25, or less than 0.1 wt% PET and / or less than 10, less than 8, less than 6, less than 4, less than 2, or less than 1 wt% PVC, on a dry plastic basis. First PET-depleted stream 132, which is a polyolefin-rich stream, can contain 0.001 wt% to 10 wt%, 0.01 wt% to 5 wt%, 0.1 wt% to 2 wt%, or 0.5 wt% to 1 wt% PVC, on a dry plastic basis.

[0162] The PET-rich output stream 142 fed to the second density separation stage 150 is separated into a second PET-rich stream 120 and a second PET-depleted stream 134, which is a heavy-rich stream and contains plastics and / or other materials with a density greater than PET. The second PET-rich stream 120 may also be PVC-rich. The second PET-rich stream 120 may be polyolefin-depleted. The second PET-depleted stream 134, which is a heavy-rich stream, may contain less than 10, less than 5, less than 1, less than 0.5, or less than 0.1 wt% PET. The second PET-depleted stream 134, which is a heavy-rich stream, may contain 0.001 wt% to 10 wt%, 0.01 wt% to 5 wt%, or 0.1 wt% to 1 wt% PET.

[0163] In one embodiment or in combination with any of the above embodiments, the second PET-depleted stream 134, being a heavy-rich stream, further comprises non-plastic solids and / or heavy plastics having a density greater than 1.45 g / cc. The non-plastic solids may include sand, metal, and / or glass. The second PET-rich stream 120 may be subjected to solid-liquid mechanical separation and / or drying to provide a PET-rich plastic material product.

[0164] In one other embodiment or in combination with any of the above embodiments, the first density separation stage 140 is a high-density separation stage and the second density separation stage 150 is a low-density separation stage. The first density separation stage 140 can produce a first PET-depleted stream 132, which is a heavy-rich stream, and a PET-rich output stream 142, which is fed into the second density separation stage 150. The PET-rich output stream 142 can also be PVC-rich. The PET-rich output stream 142 can also be polyolefin-rich. The first PET-depleted stream 132, which is a heavy-rich stream, can contain less than 10, less than 5, less than 1, less than 0.5, less than 0.25, or less than 0.1 wt% PET. The second PET-depleted stream 134, which is a heavy-rich stream, can contain 0.001 wt% to 10 wt%, 0.01 wt% to 5 wt%, or 0.1 wt% to 1 wt% PET.

[0165] Likewise, in one embodiment or in combination with any of the mentioned embodiments, the first PET-depleted stream 132, being a heavy-rich stream, further comprises non-plastic solids and / or heavy plastics having a density greater than 1.45 g / cc. Non-plastic solids may include sand, metal, and / or glass.

[0166] The PET-rich output stream 142 fed into the second density separation stage 150 is separated into a second PET-rich stream 120 and a second PET-depleted stream 134, which is a polyolefin-rich stream. In one embodiment or in combination with any of the aforementioned embodiments, the second PET-rich stream 120 is also PVC-rich. On a dry plastic basis, the second PET-depleted stream 134, which is a polyolefin-rich stream, may contain less than 10, less than 5, less than 1, less than 0.5, less than 0.25, or less than 0.1 wt% PET and / or less than 10, less than 8, less than 6, less than 4, less than 2, or less than 1 wt% PVC. On a dry plastic basis, the second PET-depleted stream 134, which is a polyolefin-rich stream, may contain 0.001 wt% to 10 wt%, 0.01 wt% to 5 wt%, 0.1 wt% to 2 wt%, or 0.5 wt% to 1 wt% PVC. The second PET-rich stream 120 may be subjected to solid-liquid mechanical separation and / or drying to provide a PET-rich plastic material product.

[0167] In one embodiment or in combination with any of the above embodiments, the first PET-rich stream 142 and the second PET-rich stream 120 described in accordance with any of the above embodiments can be recovered as PET-rich material products. However, on a dry basis, the second PET-rich stream 120 can have a higher PET concentration than the first PET-rich stream 142. On a dry plastic basis, the first PET-rich stream 142 can contain at least 75, at least 90, at least 95, at least 98, or at least 99 wt% PET. On a dry plastic basis, the second PET-rich stream 120 can contain at least 90, at least 95, at least 98, at least 99, at least 99.5, at least 99.8, or at least 99.9 wt% PET.

[0168] In one embodiment or in combination with any of the mentioned embodiments, on a dry plastic basis, first PET-rich stream 142 can comprise 75 wt%-99.9 wt%, 90 wt%-99.8 wt%, or 95 wt%-99 wt% PET. On a dry plastic basis, second PET-rich stream 120 can comprise 90 wt%-100 wt%, 95 wt%-99.9 wt%, 98 wt%-99.8 wt%, or 99 wt%-99.5 wt% PET.

[0169] The following describes embodiments of specific arrangements utilizing flotation and / or centrifugal density separation stages. It should be understood that, unless otherwise stated, the embodiments described below generally have the same or similar flow compositions, separation efficiencies, and other features described above.

[0170] In one embodiment or in combination with any of the mentioned embodiments, each of the first density separation stage 140 and the second density separation stage 150 comprises a float-sink density separation stage.

[0171] like Figure 3 As shown, in one embodiment or in combination with any of the mentioned embodiments, the first float-sink density separation stage 240 is a low density separation stage and the second float-sink density separation stage 250 is a high density separation stage.

[0172] Steering Figure 3, mixed plastic waste (MPW) pellets 210 are fed from a plastic pelletizer 208 or other source to a low-density float-sink separation stage 240. In one embodiment or in combination with any of the mentioned embodiments, the MPW pellets 210 are provided as solid plastic pellets, as described herein. As described herein, a liquid medium can be combined with the mixed plastic waste pellets 210 fed to the low-density float-sink stage 240. The liquid medium can be fed directly to the low-density float-sink stage 240 without being combined with the MPW pellet feed 210. The liquid medium can be fed to one or more other locations within the process discussed below, including into the outlet stream 242 from the first separation stage 240 and / or directly into the second separation stage 250. It should be understood that the liquid medium used in this embodiment and other embodiments described below can be selected based on the desired target separation density of the separation stage.

[0173] exist Figure 3 In the embodiment shown, the concentrated salt solution 260 is prepared by mixing a salt component 262 with water 264 to form a concentrated salt solution 260 as a liquid medium. As shown, the concentrated salt solution 260 is fed to a first 240 and a second 250 float-sink separation stage. In one embodiment or in combination with any of the embodiments mentioned, the same concentrated salt solution 260 is fed to both separation stages 240, 250, and the flow rate of the concentrated salt solution 260 to each separation stage is independently controlled such that the salt concentration in one of the first 240 or second 250 float-sink stage is greater than that in the other of the first 240 or second 250 float-sink stage. Figure 3 In the embodiment shown, the flow rate of the concentrated salt solution 260 to each separation stage is independently controlled so that the salt concentration in the first float-sink stage 240 is less than the salt concentration in the second float-sink stage 250. The salt concentration and / or flow rate can be selected or changed as needed to achieve the desired target separation density and efficiency in each density separation stage. It should be understood that within the scope of the present technology, sugar solutions or other liquid media can be used for separation. Figure 3 The same or similar process as shown.

[0174] A caustic solution 270 can also be prepared and added to the first float-sink stage 240 in combination with the MPW particles 210 or separately. In one embodiment or in combination with any of the aforementioned embodiments, the caustic solution 270 can be fed to one or more other locations in the process discussed below, including being fed to the outlet stream 242 from the first separation stage 240, being fed directly to the second separation stage 250, and / or being fed to one or more enriched streams of the first separation stage 240 or the second separation stage 250. The caustic solution 270 can be prepared by mixing the caustic component 272 with water 274. The caustic solution 270, which can be heated (not shown), is also used as a cleaning and / or disinfectant for process equipment, killing pathogens and reducing odors within the stream and / or equipment. The caustic solution 270 typically comprises an alkali (or strong base) solution. In one embodiment or in combination with any of the aforementioned embodiments, the pH of the caustic solution is greater than 7, greater than 8, greater than 9, or greater than 10. The caustic solution 270 can contain hydroxides, such as sodium hydroxide, potassium hydroxide, calcium hydroxide, lithium hydroxide, strontium hydroxide, barium hydroxide, and / or cesium hydroxide. The caustic component concentration of the caustic solution 270 can be 2 to 100 mg / L. However, as described above, the concentrated brine can contain a caustic component. Therefore, in one embodiment or in combination with any of the aforementioned embodiments, no separate caustic solution and / or caustic component is introduced into the density separation stage(s).

[0175] The low-density float-sink stage 240 produces at least two outputs, including a heavy output stream 241 and a low-density (light) stream 243, which typically primarily contains plastics with a lower density than the heavy output stream 241. In one embodiment or combination with any of the above embodiments, the heavy output stream 241 is PET-rich. The heavy output stream 241 can be PVC-rich. The low-density stream 243 can be polyolefin-rich.

[0176] exist Figure 3 In the embodiment of the present invention, the low density stream 243 and the heavy output stream 241 from the low density float and sink stage 240 are washed with water 245. The light wet plastic 248 obtained from the low density stream 241 is dried and optionally stored for use in a downstream plastic chemical recovery process.

[0177] After flushing, the PET-rich, heavy-weight output stream 242 is fed into a high-density float-sink stage 250. The high-density float-sink stage 250 produces at least two outputs, including a high-density, heavy-weight-rich stream 251 and a medium-density, PET-rich stream 253. The high-density, heavy-weight-rich stream 251 has a higher density than the medium-density, PET-rich stream 253, based on the density of the total plastic in each stream. Additionally, the medium-density, PET-rich stream 253 has a higher density than the low-density, polyolefin-rich stream 243 described above, based on the density of the total plastic in each stream. In one embodiment or combination with any of the aforementioned embodiments, the medium-density, PET-rich stream 253 is also PVC-rich. The PET-rich stream 253 from the high-density float-sink stage 250 can then be flushed with water 245 to produce a PET-rich, wet plastic product stream 220 and dried for use in downstream plastic recycling processes. The high density heavy stream 251 from the high density float and sink stage 250 can optionally be combined with the light wet plastic from the low density stream 243 to be rinsed with water 245 and dried, or the high density heavy stream 251 can be rinsed and dried separately from the light plastic. Figure 3 Although multiple flushing steps are shown in FIG, it should be understood that one or more of the flushing steps described herein are optional. While flushing can reduce the amount of certain residues (e.g., halides from salts) in the equipment, streams, and final products, in one embodiment or in combination with any of the aforementioned embodiments, the separation process and downstream chemical recovery process can be performed without removing these residues.

[0178] The water used to rinse the plastic after each separation can be recovered in one or more solid / liquid separation units 246. The recovered water 247 can be filtered 290 and / or recycled 292 back into the system for use, such as mixing with a salt or caustic solution or reuse as rinse water. Additionally or alternatively, the suspended solids component 282 can be recovered from the rinse water 247 by a flocculation process 280, which can also produce a clarified water stream 284 and / or a purified water stream 286.

[0179] like Figure 4 As shown, in one embodiment or in combination with any of the mentioned embodiments, the first float-sink density separation stage 340 is a high density separation stage and the second float-sink density separation stage 350 is a low density separation stage.

[0180] Figure 4 The embodiment shown is similar to Figure 3 Therefore, only the differences between the embodiments are discussed below.

[0181] exist Figure 4In the embodiment of the present invention, the MPW particles 210 are first fed into the high-density float-sink separation stage 340. In one embodiment or in combination with any of the aforementioned embodiments, the flow rate of the concentrated brine 260 to each separation stage is independently controlled such that the salt concentration in the first float-sink stage 340 is greater than the salt concentration in the second float-sink stage 350. Importantly, the concentrated brine 260 can be used to set and / or adjust the target separation density of the density separation stage, for example, by providing a brine having a density equal to or close to the target separation density.

[0182] High-density float-sink stage 340 produces at least two outputs, including a light output stream 343 and a high-density (heavy) stream 341, which includes plastics with a higher density than the plastics in light output stream 343. In one embodiment or combination with any of the above embodiments, light output stream 343 is PET-rich. Light output stream 343 can be PVC-rich. High-density stream 341 can be PET-depleted, PVC-depleted, and / or polyolefin-depleted.

[0183] exist Figure 4 In the embodiment of the present invention, the high density stream 341 and the light output stream 343 from the high density float and sink stage 340 are flushed with water 245. The heavy wet plastic 348 obtained from the high density stream 341 is dried and optionally stored for use in a downstream plastic chemical recovery process.

[0184] After flushing, the PET-enriched light stream 342 is fed into a low-density float / sink stage 350. The low-density float / sink stage 350 produces at least two outputs, including a low-density light-enriched stream 353 and a medium-density PET-enriched stream 351. The density of the particulate plastic solids in the low-density light-enriched stream 353 is less than the density of the particulate plastic solids in the medium-density PET-enriched stream 351. Additionally, based on the density of the total plastic in each stream, the density of the particulate plastic solids in the medium-density PET-enriched stream 351 is less than the density of the particulate plastic solids in the high-density polyolefin-depleted stream 341 described above. In one embodiment or combination with any of the aforementioned embodiments, the medium-density PET-enriched stream 351 is also PVC-enriched. The PET-enriched stream 351 from the low-density float / sink stage 350 can then be flushed with water 245 to produce a PET-enriched wet plastic product stream 220 and dried for use in downstream plastics recycling processes. The low density light stream 353 from the low density float and sink stage 350 may optionally be combined with the heavy wet plastic from the high density stream 341 to be rinsed with water 245 and dried, or the low density light stream 353 may be rinsed and dried separately from the heavy plastic.

[0185] In one embodiment or in combination with any of the mentioned embodiments, each of the first density separation stage 140 and the second density separation stage 150 comprises a centrifugal density separation stage.

[0186] like Figure 5 As shown, in one embodiment or in combination with any of the mentioned embodiments, the first centrifugal force density separation stage 440 is a low density separation stage and the second centrifugal force density separation stage 450 is a high density separation stage.

[0187] Steering Figure 5 Mixed plastic waste pellets 210 are fed from a plastic pelletizer 208 or other source to a low density centrifugal separation stage 440 (at Figure 5 cyclone separator, but it should be understood that other centrifugal separators may also be used according to the technology of this article). In one embodiment or in combination with any of the embodiments mentioned, a feed box 406 or other solid separation system can be used to remove heavy solids 412 from the mixed plastic waste particles 210 before feeding to the separation stage. The low-density centrifugal separation stage 440 can be a hydrocyclone separator. Water can be provided to the hydrocyclone as a recovery 247 of the flow from the downstream flushing process, or added separately as a dedicated water feed (not shown). A concentrated salt solution (not shown) can be prepared as described above and combined with the mixed plastic waste particles 210 or fed directly into the low-density centrifugal separation stage 440. Compared to a hydrocyclone separator using only water, the use of a concentrated salt solution in a hydrocyclone can improve the separation efficiency at the target separation density. The flow rate of the concentrated salt solution to each separation stage can be independently controlled so that the salt concentration in the first centrifugal separation stage 440 is less than the salt concentration in the second centrifugal separation stage 450.

[0188] The caustic solution 270 may also be combined with the MPW particles 210 and fed to a low density centrifugal force separation stage 440 (e.g., Figure 5 as shown) or added separately to the centrifugal separation stage without MPW particles 210.

[0189] The low-density centrifugal separation stage 440 produces at least two outputs, including a PET-rich heavy output stream 441 and a low-density (light) stream 443, which contains plastics with a lower density than the heavy output stream 441. In one embodiment or combination with any of the above embodiments, the heavy output stream 441 is PET-rich. The heavy output stream 441 can also be PVC-rich. The low-density stream 443 can be polyolefin-rich.

[0190] The low density stream 443 and the heavy output stream 441 from the low density centrifugal separation stage 440 are washed with water 245. The PET-depleted light wet plastic obtained from the low density stream 443 can be washed 246 with water 245 to form a PET-depleted stream 448, dried 498, and optionally stored for use in a downstream plastics recycling process.

[0191] After flushing, the PET-enriched heavy output stream 442 is fed to the high density centrifugal separation stage 450. Similar to the low density centrifugal separation stage 440, a concentrated brine solution (not shown) can be combined with the heavy output stream 442 and fed to the high density centrifugal separation stage 450. However, in one other embodiment or in combination with any of the mentioned embodiments, the concentrated brine solution can be fed directly to the high density centrifugal separation stage 450 without being combined with the heavy output stream 442.

[0192] High-density centrifugal separation stage 450 produces at least two outputs, including a high-density heavy stream 451 and a medium-density PET-enriched light stream 453. Based on the density of the total plastic in each stream, the high-density heavy stream 451 has a greater density than the medium-density PET-enriched light stream 453. Additionally, based on the density of the total plastic in each stream, the medium-density PET-enriched stream 453 has a greater density than the low-density polyolefin-enriched stream 443 described above. In one embodiment or combination with any of the above-mentioned embodiments, the medium-density PET-enriched stream 453 is also PVC-enriched. The PET-enriched stream 453 from high-density centrifugal separation stage 450 can then be washed with water 245 to produce the PET-enriched wet plastic product stream 220 and dried 496 for use in downstream plastics recycling processes. The high density heavy stream 451 from the high density centrifugal separation stage 450 can optionally be combined with the light wet plastic from the low density stream 443 to be washed 246 with water 245 to form a PET depleted stream 448 and dried 498, or the high density heavy stream 451 can be washed and dried separately from the light plastic.

[0193] like Figure 6 As shown, in one embodiment or in combination with any of the mentioned embodiments, the first centrifugal force density separation stage 540 is a high density separation stage and the second centrifugal force density separation stage 550 is a low density separation stage.

[0194] Figure 6 The embodiment shown is similar to Figure 5 Therefore, only the differences between the embodiments are discussed below.

[0195] exist Figure 6 In the embodiment of the present invention, the mixed plastic waste particles 210 are first fed into the high-density centrifugal separation stage 540. In one embodiment or in combination with any of the mentioned embodiments, the flow rate of the concentrated salt solution (not shown) to each separation stage can be independently controlled so that the salt concentration in the first centrifugal separation stage 540 is greater than the salt concentration in the second centrifugal separation stage 550, and thus the target separation density of the first centrifugal separation stage 540 is greater than the target separation density of the second centrifugal separation stage 550.

[0196] High-density centrifugal separation stage 540 produces at least two outputs, including a PET-rich light output stream 543 and a high-density (heavy) stream 541, which contains plastics with a higher density than the light output stream 543. In one embodiment or combination with any of the above embodiments, the light output stream 543 is PET-rich. The light output stream 543 can also be PVC-rich. The high-density stream 541 can be PET-depleted, PVC-depleted, and / or polyolefin-depleted, and is enriched in plastics with a higher density than PET.

[0197] Both the high density stream 541 and the light output stream 543 from the high density centrifugal separation stage 540 are washed 246 with water 245. The PET-depleted heavy wet plastic 548 obtained from the high density stream 541 is dried 598 and optionally stored for use in downstream plastic recycling processes.

[0198] After flushing, the PET-enriched light output stream 542 is fed into a low-density centrifugal separation stage 550. The low-density centrifugal separation stage 550 produces at least two outputs, including a low-density light stream 553 and a medium-density PET-enriched heavy stream 551. The low-density light stream 553 has a density less than that of the medium-density PET-enriched heavy stream 551, based on the density of the total plastic in each stream. Additionally, the medium-density PET-enriched stream 551 has a density less than that of the high-density polyolefin-depleted stream 541, described above, based on the density of the total plastic in each stream. In one embodiment or combination with any of the aforementioned embodiments, the medium-density PET-enriched stream 551 is also PVC-enriched. The PET-enriched stream 551 from the low-density centrifugal separation stage 550 can then be flushed 246 with water 245 to produce a PET-enriched wet plastic product stream 220 and dried 596 for use in downstream plastics recycling processes. The low density light stream 553 from the low density centrifugal separation stage 550 can optionally be combined with the heavy wet plastics from the high density stream 541 to be washed 246 with water 245 to form a PET depleted stream 548 and dried 598, or the low density light stream 553 can be washed and dried separately from the heavy plastics.

[0199] In one embodiment or in combination with any of the mentioned embodiments, one of the first density separation stage 140 and the second density separation stage 150 comprises a float density separation stage and the other of the first density separation stage 140 and the second density separation stage 150 comprises a centrifugal density separation stage.

[0200] Reference again Figure 2In one embodiment or in combination with any of the recited embodiments, the first density separation stage 140 is a float-sink separation stage, and the second density separation stage 150 is a centrifugal separation stage. In one or more such embodiments, the waste plastic separation process generally includes introducing the MPW particles 110 into the float-sink separation stage, and feeding the output 142 from the float-sink separation stage into the centrifugal separation stage.

[0201] Reference again Figure 2 In one embodiment or in combination with any of the aforementioned embodiments, the first density separation stage 140 is a centrifugal separation stage, and the second density separation stage 150 is a float-sink separation stage. In one or more such embodiments, the waste plastic separation method includes introducing the MPW particles 110 into the centrifugal separation stage, and feeding the output 142 from the centrifugal separation stage to the float-sink separation stage.

[0202] like Figure 7 As shown in , in one embodiment or in combination with any of the described embodiments, the first density separation stage 640 is a high density float-sink separation stage and the second density separation stage 650 is a low density centrifugal force separation stage.

[0203] Figure 7 The embodiment shown is similar to Figure 4 Therefore, only the differences between the embodiments are discussed below.

[0204] exist Figure 7 In the embodiment of the present invention, the MPW particles 210 are first fed to the high density float-sink separation stage 640. In one embodiment or in combination with any of the above embodiments, the flow rate of the concentrated brine 260 to each separation stage is independently controlled to achieve the desired target separation density and separation efficiency for each stage.

[0205] High-density float-sink stage 640 produces at least two outputs, including a light output stream 643 and a high-density (heavy) stream 641. The PET-enriched light stream 643 is flushed 246 and fed to a low-density centrifugal separation stage 650. Low-density centrifugal separation stage 650 produces at least two outputs, including a low-density light-enriched stream 653 and a medium-density PET-enriched stream 651. The density of the particulate plastic solids in low-density light-enriched stream 653 is less than the density of the particulate plastic solids in medium-density PET-enriched stream 651. Additionally, the density of the particulate plastic solids in medium-density PET-enriched stream 651 is less than the density of the particulate plastic solids in high-density polyolefin-depleted stream 641. In one embodiment or combination with any of the aforementioned embodiments, medium-density PET-enriched stream 651 is also PVC-enriched. The PET-enriched stream 651 from low-density centrifugal separation stage 650 can then be flushed 246 with water 245 to produce a PET-enriched wet plastic product stream 220 and dried for use in downstream plastics recycling processes. The low density light stream 653 from the low density centrifugal force separation stage can optionally be combined with the heavy wet plastics from the high density stream 641 to be washed 246 with water 245 to form a PET depleted stream 648 and dried, or the low density light stream 653 can be washed separately from the heavy plastics and dried.

[0206] In one embodiment or in combination with any of the aforementioned embodiments, a facility and system for processing particulate plastic solids mixed with plastic waste obtained from the separation systems and processes described herein are also provided. In particular, the particulate plastic solids processing facility includes at least one enclosed structure and a batch or continuous conveying system associated with the at least one enclosed structure, the conveying system being configured to selectively deposit the particulate plastic solids into the plastic solids transport system, the plastic solids transport system interconnecting the processing facility with a plastic chemical recycling facility and / or at least one stockpile within the at least one enclosed structure. In one embodiment or in combination with any of the aforementioned embodiments, the batch or continuous conveying system includes one or more of an elongated overhead conveyor, a front-end loader, and / or a truck.

[0207] In one embodiment or in combination with any of the mentioned embodiments, the amount of particulate plastic solids is provided from a feedstock comprising mixed plastic waste (also referred to herein as MPW). Figure 8, such feedstock 710 is provided. The feedstock 710 can be any mixed plastic waste described herein, such as waste plastic obtained from a material recovery facility or a plastics recycling facility. The mixed plastic waste feedstock 710 typically comprises plastic solids having at least one dimension greater than 2.54 cm (one inch), greater than 1.91 cm (0.75 inches), or greater than 1.27 cm (0.5 inches), such as used containers. In one embodiment or combination with any of the recited embodiments, the mixed plastic waste feedstock 710 comprises plastic solids having at least one dimension between 1.27 cm and 25.4 cm, between 1.91 cm and 19.1 cm, or between 2.54 cm and 12.7 cm.

[0208] The mixed plastic waste feedstock 710 may also include a plurality of plastic solids that at one time had at least one dimension greater than 2.54 cm (one inch), but these solids may have been compacted, pressed, or otherwise aggregated into larger units, such as bales. However, plastic solids that have at least one dimension greater than 2.54 cm (one inch), greater than 1.91 cm (0.75 inches), or greater than 1.27 cm (0.5 inches) are not ideal for the separation and / or recovery processes described herein. Therefore, in one embodiment or in combination with any of the mentioned embodiments, the feedstock 710 is subjected to a mechanical size reduction operation 715, such as grinding, shredding, chopping, shredding, or other comminution process that results in the production of particles having a smaller size than the material fed to the size reduction operation. It is important to note that the mechanical size reduction operation 715 includes size reduction other than crushing, compacting, or forming the plastic into bales.

[0209] After mechanical reduction 715, the particles of mixed plastic waste are directed to a separation process 740 as described herein to sort the particles into at least one polyethylene terephthalate 720 enriched stream and at least one polyolefin 730 enriched stream, wherein the enrichment is relative to the feed stream to the separation process 740. In one embodiment or in combination with any of the mentioned embodiments, the enriched streams 720, 730 from the separation process 740 can then be used in a chemical recovery process.

[0210] Figure 9 More detailed embodiments are described in which mixed plastic waste is made into a sorted plastic pellet stream rich in polyethylene terephthalate or polyolefins.

[0211] It can be seen that unsorted mixed plastic waste (as raw material) 710, which can be obtained from a variety of sources as described above, is transported to the site, for example, by train car or tractor trailer. In one embodiment or in combination with any of the embodiments mentioned, the unsorted plastic waste may contain various organic pollutants or residues that may be associated with the previous use of the plastic waste material. For example, the plastic waste may contain food or beverage contaminants, particularly if the plastic material is used for food or beverage packaging. Therefore, mixed plastic waste may also contain microbial contaminants that grow on and consume the food or beverage residues present in the plastic waste, as well as compounds produced by microorganisms. Exemplary microorganisms that may be present on the plastic solid surface that constitutes the mixed plastic waste include Escherichia coli, Salmonella, Clostridium difficile (C.difficile), Staphylococcus aureus, Listeria monocytogenes, Staphylococcus epidermidis, Pseudomonas aeruginosa, and Pseudomonas fluorescens. Various microorganisms can produce compounds that cause malodors. Exemplary odor-causing compounds include hydrogen sulfide, dimethyl sulfide, methyl mercaptan, putrescine, cadaverine, trimethylamine, ammonia, acetaldehyde, acetic acid, butanoic acid, propionic acid, and / or butyric acid. It will be appreciated, therefore, that mixed plastic waste may present an odor nuisance problem. Thus, in one embodiment or in combination with any of the aforementioned embodiments, the mixed plastic waste can be stored in an enclosed space, such as a shipping container, an enclosed rail car, or an enclosed trailer, until it can be further processed. In certain embodiments, once the mixed plastic waste arrives at the location where the plastic waste is to be sorted, it is stored in an enclosed space for no more than one week, no more than five days, no more than three days, no more than two days, or no more than one day.

[0212] In one embodiment or in combination with any of the aforementioned embodiments, any odor generated by mixed plastic waste or granular plastic solids can be assessed by sampling the headspace air within the enclosed space containing the plastic. For example, odor can be quantitatively assessed by directly measuring the concentration of any odor-causing compounds present in the sample using, for example, gas chromatography. Additionally and / or alternatively, odor can be qualitatively assessed by using an "odor panel" consisting of a number of individuals who sniff samples of the headspace air and then assign an odor rating to each sample. The results of the odor panel survey can then be statistically analyzed to determine whether any odor remediation steps are necessary for certain plastic materials.

[0213] In one embodiment or in combination with any of the aforementioned embodiments, mixed plastic waste is provided in the form of unsorted or pre-sorted plastic bales or other large aggregates. The bales or aggregates of plastic undergo an initial process in which they are broken down. In one embodiment or in combination with any of the aforementioned embodiments, the plastic bales may be fed to a bale splitter 702, which may include, for example, one or more rotating shafts equipped with teeth or blades configured to separate the bales and, in some cases, shred the plastic components of the bales. In another embodiment or in combination with any of the aforementioned embodiments, the bales or aggregates of plastic may be fed to a guillotine cutter 704, where they are cut into smaller plastic pieces. The unpacked and / or guillotine-cut plastic solids may then undergo a sorting process 706, in which various heavy, non-plastic materials, such as glass, metal, and rock, are removed. This sorting process 706 may be performed manually or by machine. In one embodiment or in combination with any of the aforementioned embodiments, the sorter may rely on optical sensors, magnets, or sieves to identify and remove heavy materials.

[0214] As explained above, mixed plastic waste can contain multilayer polymers and / or other multicomponent polymers that contain two or more synthetic or natural polymer components and / or non-polymer solids that are associated together in combination or otherwise. When polymer components with a density less than that of PET (e.g., nylon and polyolefins) are combined or associated with PET, the effective density of such multilayer plastics and multicomponent plastics is also less than the density of PET. Therefore, during the density separation process, such multilayer polymers and multicomponent polymers are separated into a PET-depleted stream, such as a polyolefin-rich stream. Similarly, when polymer and non-polymer solid components with a density greater than that of PET (e.g., metals and heavy plastics) are combined or associated with PET, the effective density of such multilayer plastics and multicomponent plastics is also greater than the density of PET. Therefore, during the density separation process, such multilayer polymers and multicomponent polymers are separated into a PET-depleted stream, such as a heavy-rich stream. Although this may result in an acceptably high PET purity in the PET-rich stream, excessive PET yield loss may occur due to the separation of the combined or associated PET into the PET-depleted stream. In one embodiment or in combination with any of the mentioned embodiments, the mixed plastic waste may be subjected to one or more pre-washing and / or friction washing processes (not shown) before being fed to the density separation process. As described above, such pre-washing and / or friction washing processes are particularly effective in separating nylon and other synthetic or natural polymers or non-polymeric solids associated with PET in the form of multi-layer polymers or other multi-component polymers. For example, the friction forces applied to the plastic articles and / or particles in these processes may pull apart and de-associate the individual plastic components in the multi-layer polymer. Grinders and / or other diameter reducing processes may have similar effects. Additionally, or alternatively, the use of caustic solutions and / or heat may also separate individual components in the multi-layer polymer, particularly those associated by adhesives. In one embodiment or in combination with any of the mentioned embodiments, one or more density separation processes may also be effective in separating individual components of the multi-layer polymer or other multi-component polymer, particularly density separation processes that use a caustic liquid medium and / or apply friction to the particles (e.g., hydrocyclones). When the multicomponent polymer comprises a heterogeneous mixture of PET, a compatibilizer, and at least one other synthetic or natural polymer or non-polymeric solid combined in a single phase, the friction scrubber and / or cyclone separator can apply sufficient energy to separate these components, particularly with sufficient heat and a caustic solution at a high pH.

[0215] In another embodiment, or in combination with any of the aforementioned embodiments, the mixed plastic waste may have already undergone some initial separation and / or size reduction process. Specifically, the mixed plastic waste may be in the form of pellets or flakes and provided in some type of container, such as a sack. Depending on the composition of the plastic solids and any pre-processing they may have undergone, the plastic pellets may bypass the bale remover 702, the guillotine cutter 704, and / or the heavy material removal station 706 and proceed directly to the pelletizing unit 708 for further size reduction.

[0216] In one embodiment or in combination with any of the above embodiments, the unpacked or crushed plastic solids are sent to a comminution or pelletizing device 708 where the plastic solids are ground, shredded, or otherwise reduced in size. The plastic material can be formed into pellets having an average D90 particle size of less than 2.54 cm (1 inch), less than 1.91 cm (3 / 4 inch), or less than 1.27 cm (1 / 2 inch). The average D90 particle size of the plastic material exiting the pelletizing device can be 0.16 cm (1 / 16 inch) to 2.54 cm (1 inch), 0.32 cm (1 / 8 inch) to 1.91 cm (3 / 4 inch), 0.64 cm (1 / 4 inch) to 1.59 cm (5 / 8 inch), or 0.95 cm (3 / 8 inch) to 1.27 cm (1 / 2 inch).

[0217] Once reduced in diameter, the granulated plastic can be fed to a density separation process, such as those described herein. Typically, however, the density separation process includes a first 740 and a second 750 density separation stage that produce at least two plastic streams having different densities. Each stream exiting each separator undergoes a mechanical dewatering process 746. At least a portion of the plastic stream from the first density separation stage 740 is sent to a second density separation stage 750, which again produces at least two plastic streams having different densities. Figure 9 As shown, the product stream from the first density separation stage 740 is combined with the product stream from the second density separation stage 750. In one embodiment, or in combination with any of the aforementioned embodiments, these streams comprise a polyolefin-rich stream, including both higher-density and lower-density polyolefins. The other product stream from the second density separation stage 750 can be a polyethylene terephthalate-rich stream. The product streams are then dried 796, 798 to form a quantity of polyolefin-rich plastic solids 730 and polyethylene terephthalate-rich plastic solids 720.

[0218] In one embodiment or in combination with any of the above embodiments, the process produces one or more quantities of particulate plastic solids. One such quantity of particulate plastic solids comprises greater than 70 wt%, greater than 75 wt%, greater than 80 wt%, greater than 85 wt%, greater than 90 wt%, or greater than 95 wt% polyethylene terephthalate. A quantity of particulate plastic solids may comprise 70 wt% to 99 wt%, 75 wt% to 95 wt%, or 80 wt% to 90 wt% polyethylene terephthalate (PET).

[0219] In one embodiment or combination with any of the mentioned embodiments, the amount of particulate plastic solids comprises less than 20 wt%, less than 15 wt%, less than 10 wt%, less than 7.5 wt%, less than 5 wt%, less than 2.5 wt%, or less than 1 wt% of halogen and / or halogen-containing compounds, such as polyvinyl chloride. The amount of particulate plastic solids may comprise 0.1 wt%-10 wt%, 0.5 wt%-3 wt%, 1 wt%-2.5 wt%, or 1.25 wt%-2 wt% of halogen, such as polyvinyl chloride.

[0220] As described herein, halide-containing salts can be used to assist in the density separation of granular plastic solids. In one embodiment or in combination with any of the embodiments mentioned, it is desirable to wash the separated granular plastic to remove these salt residues (and halides) because the presence of halides may adversely affect downstream plastic processing and chemical recovery equipment, depending on the metallurgy of the equipment. Therefore, in one embodiment or in combination with any of the embodiments mentioned, a certain amount of granular plastic solids comprises less than 1000ppm, less than 800ppm, less than 600ppm, less than 400ppm, less than 300ppm, less than 200ppm or less than 100ppm of halide. A certain amount of granular plastic solids can comprise a halide content of 50ppm to 1000ppm, 75ppm to 800ppm, 100ppm to 600ppm or 125ppm to 400ppm. By keeping the level of halide below these levels, the corrosive effect of halides on certain metals can be reduced or avoided, and the metal can be used to construct processing equipment.

[0221] In one embodiment or in combination with any of the above embodiments, the amount of particulate plastic solids comprises a moisture content of less than 4 wt%, less than 3 wt%, less than 2 wt%, or less than 1 wt%. The amount of particulate plastic solids can comprise a moisture content of 0.1 wt%-4 wt%, 0.5 wt%-3 wt%, 0.75 wt%-2.5 wt%, or 1 wt%-2 wt%.

[0222] In one embodiment or combination with any of the above embodiments, the amount of particulate plastic solids comprises at least 0.1 wt%, at least 1 wt%, at least 5 wt%, at least 10 wt%, at least 20 wt%, or at least 40 wt% of a solid material that does not undergo a phase change below 270° C. and 1 atm. The phase change referred to herein can be melting, evaporation, or sublimation. The solid material present in the amount of particulate plastic solids can include glass, aluminum, ferrous metals (such as steel and stainless steel), other non-ferrous metals, rocks, minerals, cross-linked polyethylene (PEX), polytetrafluoroethylene, calcium carbonate, and / or polyvinyl chloride.

[0223] In one embodiment or in combination with any of the embodiments mentioned, separation of granular waste plastic solids comprises treating the granules with a chemical composition having antimicrobial properties, thereby forming treated granular plastic solids. As discussed herein, sodium hydroxide, potassium carbonate and / or other caustic components can be used to assist in various density separation processes. Caustic solutions, such as sodium hydroxide, potassium carbonate and / or other caustic components are used in sufficient amounts to control the growth of microorganisms present in the granular plastic solids and / or achieve a reduction in their levels while achieving separation at a target density. From a human and animal health perspective, the benefits of controlling microorganisms (some of which may be pathogenic) in a certain amount of granular plastic solids are obvious. However, microbial growth on granular plastic solids may result in the production of organic residue decomposition products or microbial metabolites that may be malodorous. Therefore, controlling the level of microorganisms may also reduce the level of malodorous compounds in the plastic solids. In one embodiment or in combination with any of the embodiments mentioned, the microbial content of one or each inventory pile of treated granular plastic solids, or PET depleted piles or PET enriched piles, may be less than 10 9 CFU / g, less than 10 7 CFU / g, less than 10 6 CFU / g, less than 10 5 CFU / g, or less than 10 4 CFU / g, or less than 10 3 CFU / g, or less than 5×10 2 CFU / g, or no more than 10 2 CFU / g, or no more than 5×10 1 CFU / g, or not more than 40 CFU / g, or not more than 30 CFU / g, or not more than 20 CFU / g, or not more than 10 CFU / g.

[0224] In one embodiment or in combination with any of the mentioned embodiments, the microbial (e.g., fungal and / or bacterial) count of the unsorted mixed plastic waste may be greater than 10 5 CFU / g, greater than 10 6CFU / g, greater than 10 7 CFU / g, greater than 10 8 CFU / g, greater than 10 9 CFU / g or greater than 10 10 CFU / g.

[0225] The microbial count in the processed particulate plastic solids or in either or both of the stockpiles can have a lesser or reduced microbial count relative to the unsorted mixed plastic waste stream. As discussed below, this reduction can be achieved without applying an antimicrobial agent to the plastic in excess of that contained in the caustic solution at the float-sink density separation stage, or without applying any antimicrobial agent to the plastic at any stage of the feed from the mixed plastic waste to the stockpiles, other than the caustic solution at the float-sink density separation stage. The level of reduction in microbial count from the mixed plastic waste feed to the stockpiles can be variable and can be an amount of at least 10%, or at least 20%, or at least 30%, or at least 40%, or at least 50%, or at least 60%, or at least 70%, or at least 80%, or at least 90%, or at least 95%, or at least 97%, or at least 98%, or at least 99%, calculated by the following formula:

[0226]

[0227] Wherein MCmpw is the microbial count of the mixed plastic waste feed and MCtpp is the microbial count of the treated granular plastic solids. The microbial count is determined by any of the procedures described herein. In one embodiment or in combination with any of the mentioned embodiments, the polyolefin-rich stream of granular plastic solids from the separation process exhibits a reduction in microbial (e.g., fungal and / or bacterial) count of at least 80%, at least 90%, at least 99%, at least 99.9%, at least 99.99%, or at least 99.999% relative to the unsorted mixed plastic waste from which it is derived. The PET-rich stream of granular plastic solids from the separation process exhibits a reduction in microbial (e.g., fungal and / or bacterial) count of at least 80%, at least 90%, at least 99%, at least 99.9%, at least 99.99%, or at least 99.999% relative to the unsorted mixed plastic waste from which it is derived. The microbial count can be determined according to any acceptable method known in the art, including those described herein. For example, bacterial counts can be determined by sampling unsorted mixed plastic waste and polyolefin-rich and PET-rich streams and growing bacterial colonies using plate count agar (PCA) medium. Fungal counts can be determined by sampling unsorted mixed plastic waste and polyolefin-rich and PET-rich streams and growing fungal colonies using Sabouraud dextrose agar (SDA) medium.

[0228] In one embodiment or in combination with any of the aforementioned embodiments, the process that results in a reduction in microbial count can have a long-lasting effect because microbial reproduction is controlled and / or inhibited. The reduced microbial levels in the polyolefin and PET enriched streams, such as those described above, can be maintained for a period of at least 12 hours, at least 24 hours, at least 2 days, at least 5 days, at least 7 days, or at least 14 days. A reduction in microbial levels in the granular plastic material can be observed when the granular plastic material is placed in one or more stockpiles for the aforementioned periods of time. Samples can be taken daily from one or more stockpiles over a given period of time and the microbial levels determined using the method described below for determining microbial counts. The granular plastic material, having undergone the separation process and placed in one or more stockpiles, can exhibit a reduction of at least 80%, at least 90%, at least 99%, at least 99.9%, at least 99.99%, or at least 99.999% in any of the aforementioned microbial counts, measured daily for a period of at least 12 hours, at least 24 hours, at least 2 days, at least 5 days, at least 7 days, or at least 14 days. The particulate plastic solids exhibiting microbial control and / or reduced microbial levels comprising one or more stockpiles are relatively dry (i.e., low moisture) and may have a moisture content of less than 4 wt%, less than 3 wt%, less than 2 wt%, or less than 1 wt%.

[0229] In one embodiment or in combination with any of the mentioned embodiments, the above-mentioned reduction in microbial count is obtained by washing the particulate mixed plastic waste or sorted particulate plastic solids in a caustic wash using any of the caustic materials described herein. Alternatively, or additionally, the reduction in microbial count is obtained by a density separation process comprising a liquid density separation medium, particularly a caustic medium, as described herein.

[0230] In one embodiment or in combination with any of the mentioned embodiments, reduced microbial counts are obtained in particulate plastic solids that are dried and / or sorted into PET-rich and / or polyolefin-rich streams and optionally placed in one or more stockpiles without applying any antimicrobial agents, except for the above-described caustic wash and / or density separation media employed in the density separation process.

[0231] In one embodiment or in combination with any of the mentioned embodiments, a reduced microbial count is obtained in the particulate plastic solids after the last density separation stage or step, or after a drying step by applying external heat energy in a container, or after the last liquid density separation step, without applying any antimicrobial agent, the particulate plastic solids being dried and / or sorted into PET-rich and / or polyolefin-rich streams and optionally placed in one or more stockpiles.

[0232] In one embodiment or in combination with any of the embodiments mentioned, by applying an antimicrobial composition simultaneously with a float-sink density separation stage or step, also referred to as an in-situ microbial reduction method, a microbial count reduction in a granular plastic solid is obtained, the granular plastic solid being dried and / or sorted into a PET enrichment and / or polyolefin enrichment stream, and optionally placed in one or more stockpiles. The antimicrobial composition can be a solution for realizing plastic separation by density, such as a caustic solution, or can be a density separation solution to which an antimicrobial agent is added. In the float-sink separation stage, an antimicrobial count can be obtained without adding any antimicrobial agent to the caustic solution, or without adding any antimicrobial agent to any density separation stage, or without contacting any other reagent with the mixed plastic waste stream or separated plastics or stockpiles except those forming caustic solutions mentioned herein.

[0233] The level of microorganisms present in a quantity of granular plastic solids may be tested according to one of the following procedures, including: USP 34(6) <61> Microbiological examination of non-sterile products: Microbial enumeration test, and ISO 4833-2:2015 Microbiology of the food chain — Horizontal methods for the enumeration of microorganisms — Part 2: Colony counts at 30°C by surface plating technique, are both incorporated herein by reference in their entirety.

[0234] In one embodiment or combination with any of the mentioned embodiments, the basic method of analysis includes sampling the plastic, preparing the sample, plating a portion of the sample onto a nutrient medium, incubating the plate to grow the microorganisms, and then counting the resulting colonies.

[0235] In one embodiment or in combination with any of the aforementioned embodiments, sampling of the amount of particulate plastic material is performed by collecting at least five random samples from different locations within the amount, each sample weighing about 10 to 100 grams. Alternatively, the five random samples can be obtained by first collecting a larger sample (e.g., 2.27 kg (5 lbs)) and then removing 10-100 gram samples from this initial larger sample. The purpose of the sampling is to provide a representation of the state of the entire amount of particulate plastic solids.

[0236] Sample preparation can be adjusted by any of the above methods by replacing the drug or food samples described in the standard with granular plastic solid samples. The sample is collected aseptically and placed in a sterile container (e.g., a polymer bag) and then taken to the laboratory where a portion of the sample is weighed into a suitable container (e.g., a polymer bag) or a glass or plastic jar / cup. A certain volume of appropriate buffer / diluent is added, typically 10 times the sample weight. Typical buffers / diluents that can be used include buffered sodium chloride-peptone solution with a pH value of 7.0, phosphate buffer solution with a pH value of 7.2, soybean-casein digest, peptone water, and Butterfield's phosphate diluent. Surfactants, such as one gram of polysorbate 80, can be added per liter to enhance surface wetting and remove microorganisms from plastics. The container is sealed and then mixed manually or by a mechanical device. Exemplary mechanical devices include orbital shakers or hand-shake shakers and ultrasonic baths. Mixing is carried out for at least 30 seconds but no more than 30 minutes. Further dilution can be included to allow quantification of higher contamination levels.

[0237] After sample preparation, a portion of the sample is plated onto a nutrient medium following standard methods to cultivate microorganisms (such as bacteria and fungi) at an appropriate temperature and time. Finally, the resulting colonies are counted, and the concentration of the resulting bacteria and fungi is determined by multiplying the colony count by the dilution.

[0238] In one embodiment or in combination with any of the above embodiments, the quantity of particulate plastic solids is isolated from other quantities of plastic solids, particularly other quantities of particulate plastic solids. The quantity of particulate plastic solids can be unpackaged or "loose" in that they can be accumulated on a floor or other platform rather than confined in a walled container.

[0239] Figure 10 An exemplary plastic separation facility 700 is shown, according to one embodiment or in combination with any of the mentioned embodiments. The facility 700 includes infrastructure for receiving mixed plastic waste as described herein. Such infrastructure can accommodate mixed plastic waste (in Figure 10 The facility is designed to deliver mixed plastic waste feedstock 710 (shown as unsorted plastic waste feedstock 710) by any useful type of vehicle, such as a train, truck, or ship (if the facility is located near a body of water), and includes equipment to assist in unloading the mixed plastic waste from the vehicle. Once unloaded, the waste plastic 710 can be processed as described above to produce mixed waste plastic pellets. These pellets are then transported 712 to the waste plastic separation system 745, where the exemplary separation process is Figure 2-7The conveying system used to transport the granular plastic waste can be any type capable of transporting granular material, depending on the distance between the facility's unloading infrastructure and the waste plastic separation system. Exemplary conveying systems include pneumatic conveyors, belt conveyors, bucket conveyors, vibratory conveyors, screw conveyors, cart-on-track conveyors, drag conveyors, overhead conveyors, front-end loaders, trucks, and chain conveyors.

[0240] In one embodiment or in combination with any of the mentioned embodiments, the distance between the unsorted waste plastic unloading station and the waste plastic separation system is less than 1609.34 m (one mile), less than 1371.60 m (1500 yards), less than 1143 m (1250 yards), less than 914.40 m (1000 yards), less than 685.80 m (750 yards), less than 457.20 m (500 yards), less than 228.60 m (250 yards) or less than 91.44 m (100 yards).

[0241] After separation of the waste plastic particulate solids within the waste plastic separation system 745, at least two waste plastic particulate streams are generated: one rich in polyethylene terephthalate and one rich in polyolefins. In one embodiment or in combination with any of the aforementioned embodiments, these different streams can be conveyed 722, 732 directly to a downstream chemical recovery process, conveyed 723, 733 to storage areas 724, 734 to await transport to a downstream chemical recovery process, or both simultaneously.

[0242] In one embodiment or in combination with any of the aforementioned embodiments, the storage areas 724, 734, discussed in greater detail below, are enclosed structures comprising a granular plastic solids inlet for receiving a stream from the separation system and a granular plastic solids outlet for removing the granular plastic solids from the enclosed structure for transport to a downstream chemical recovery process. The inlet and outlet can be interconnected by a conveying system associated with the enclosed structure, which can be disposed within or outside the enclosed structure. The conveying system can include equipment for diverting the stream of granular plastic solids carried thereby and depositing them within the enclosed structure as one of the aforementioned quantities of granular plastic solids.

[0243] In one embodiment or in combination with any of the above embodiments, the amount of particulate plastic solids stored in the enclosed structure is greater than 76.46 m 3 (100yd 3 ), greater than 382.28m 3 (500yd 3 ) or greater than 764.56m 3 (1000yd 3 The amount of granular plastic solids stored in the closed structure can be 76.46m 3(100yd 3 ) to 191,139m 3 (250,000yd 3 ), or 382.28m 3 (500yd 3 ) to 152,911m 3 (200,000yd 3 ), or 764.56m 3 (1000yd 3 ) to 76,455m 3 (100,000yd 3 ). The amount of particulate plastic solids can be sufficient to operate the downstream chemical recovery process for at least 24 hours, at least 7 days, at least 14 days, or at least 21 days. The amount of particulate plastic solids can be sufficient to operate the downstream chemical recovery process for 24 hours to 90 days, or 7 days to 75 days, or 14 days to 60 days, or 21 days to 45 days. In one embodiment or combination with any of the above embodiments, the amount is an isolated amount. The amount can be isolated from the separation process because it is not in continuous fluid or continuous solid / solid communication with the separation process.

[0244] In one embodiment or in combination with any of the aforementioned embodiments, particulate plastic solids can be transported directly between the particulate plastic solids inlet and outlet of the closed structure without being stored within the structure for any appreciable length of time. However, if the inflow of particulate plastic solids is insufficient to meet downstream demand for the particulate plastic solids, the shortfall can be made up by utilizing the particulate plastic solids present in the amount stored within the closed structure. When the inflow of particulate plastic solids is greater than the downstream demand for the particulate plastic solids, a portion of the particulate plastic solids can be stored within the closed structure for later use. Thus, over time, particulate plastic solids can be added to and removed from the amount stored within the closed structure, resulting in a rotation of the particulate plastic solids present in the amount.

[0245] In one embodiment or combination with any of the mentioned embodiments, the amount of particulate plastic solids has a volume of at least 764.56 m 3 (1000yd 3), and the average D90 particle size within a certain amount of particulate plastic solids during this one-month period is less than 2.54 cm (1 inch), less than 1.91 cm (3 / 4 inch), or less than 1.27 cm (1 / 2 inch). The monthly average D90 particle size of the particulate plastic solids in the storage volume in the closed structure may be 0.16 cm (1 / 16 inch) to 2.54 cm (1 inch), 0.32 cm (1 / 8 inch) to 1.91 cm (3 / 4 inch), 0.64 cm (1 / 4 inch) to 1.59 cm (5 / 8 inch), or 0.95 cm (3 / 8 inch) to 1.27 cm (1 / 2 inch).

[0246] In one embodiment or in combination with any of the mentioned embodiments, the amount of particulate plastic solids comprises at least 764.56 m 3 (1000yd 3 ), at least 1911.39m 3 (2500yd 3 ), at least 3822.77m 3 (5000yd 3 ), at least 7645.55m 3 (10000yd 3 ) or at least 15291.10m 3 (20000yd 3 ) of particulate plastic solids, which have been part of that amount for at least 24 hours, at least 48 hours, or at least 72 hours.

[0247] In one embodiment or in combination with any of the embodiments mentioned, at least two amounts of plastic solids of different composition are co-located. One or more specific embodiments relate to at least first and second amounts of plastic solids co-located, wherein the first amount of plastic solids comprises plastic material that has not been treated to reduce the level of microorganisms thereon, and wherein the second amount of plastic solids comprises plastic material that has been treated to reduce the level of microorganisms thereon. The first amount of plastic solids may comprise mixed waste plastics as described herein. The first amount comprises plastic solids in bulk form (e.g., in bales) that have not undergone a mechanical comminution process. Alternatively, the first amount comprises plastic solids that have undergone a reducing operation, such as grinding, shredding, chopping, unpacking, pelletizing, or granulating. In one embodiment or in combination with any of the embodiments mentioned, the first amount need not be contained in an enclosed structure and may exist as a non-enclosed pile exposed to the natural environment. In a specific embodiment or in combination with any of the embodiments mentioned, the second amount of plastic solids comprises plastic solids that have been enriched in polyethylene terephthalate or polyolefin relative to the first amount of plastic solids. The second amount of plastic solids may also have undergone a mechanical comminution process, as described herein.

[0248] In one further embodiment or in combination with any of the aforementioned embodiments, the first amount of plastic solids comprises plastic solids, particularly particulate plastic solids, that have been treated to reduce the level of microorganisms thereon, such as described herein and having the qualities described herein. In a specific embodiment or in combination with any of the aforementioned embodiments, the first amount of plastic solids comprises particulate plastic solids that have been enriched with polyethylene terephthalate or polyolefin. In a specific embodiment, the first amount of plastic solids is enriched in polyolefin relative to the second amount of plastic solids, and the second amount of plastic solids is enriched in polyethylene terephthalate relative to the first amount of plastic solids. The second amount of plastic solids may comprise plastic solids that have been subjected to a mechanical comminution process.

[0249] In one embodiment or in combination with any of the aforementioned embodiments, the first and second co-located quantities of plastic solids are not intermixed and remain as separate, discrete quantities. The first quantity of plastic solids can be contained within at least one first enclosed structure. For example, the first quantity of plastic solids can be placed within more than one enclosed structure, such as a newly constructed or repurposed existing structure. The second quantity of plastic solids is present in a non-enclosed pile, contained within at least one first enclosed structure, or contained within at least one separate second enclosed structure. For example, the first and second quantities of plastic solids can be placed within the same enclosed structure that has been separated, such as by one or more walls (e.g., concrete walls), so that intermixing between the first and second quantities of plastic solids is prevented. The first and second enclosed structures can be positioned relative to each other in series (with the structures aligned longitudinally) or in parallel (with the longitudinal structures spaced apart transversely). However, it is within the scope of the present technology to contain the first and second quantities of plastic solids within a common enclosed structure without intermixing the quantities. For example, the first and second quantities of plastic solids can be arranged in series (i.e., stored near opposite ends of the enclosed structure and separated by a wall extending transversely to the length of the enclosed structure). Alternatively, the first amount of plastic solids can be positioned in parallel with the second amount of plastic solids (i.e., disposed on opposite sides of a wall extending parallel to the length of the enclosure). In one specific embodiment or in combination with any of the aforementioned embodiments, the first enclosure is located less than 1609.34 m (one mile), less than 1371.60 m (1500 yards), less than 1143 m (1250 yards), less than 914.40 m (1000 yards), less than 685.80 m (750 yards), less than 457.20 m (500 yards), less than 228.60 m (250 yards), or less than 91.44 m (100 yards) from the second enclosure.

[0250] In one embodiment or in combination with any of the mentioned embodiments, each first and / or second enclosed structure includes an overhead conveying system operable to deposit respective quantities of plastic solids into one or more piles within the structure or directly into a conveyor device configured to transport the plastic solids to a downstream chemical recycling process.

[0251] Figure 11 Another embodiment is depicted in which a facility for processing plastic solids 800 is located between the waste plastic separation system 745 and the plastic chemical recycling facility 900. The waste plastic separation system 745 can be any process, system, or apparatus described herein configured to separate mixed waste plastic into at least one polyethylene terephthalate-rich stream and at least one polyethylene terephthalate-depleted stream. One or more of these output streams from the waste plastic separation system 745 is delivered to the plastic solids processing facility 800. As described in more detail below, the plastic solids processing facility 800 can serve as a transfer station and / or storage station for granular plastic solids on their way to the plastic chemical recycling facility 900.

[0252] In one embodiment or in combination with any of the mentioned embodiments, a facility for processing plastic solids 800 separated from mixed plastic waste comprises an enclosed structure, such as any of the enclosed structures described herein, and an elongated overhead conveyor associated with the enclosed structure. Figure 12 An exemplary plastic solids processing facility 800 is schematically depicted. The plastic solids processing facility 800 can be co-located with the waste plastics separation system 745. The plastic solids processing facility can be located less than 1609.34 m (one mile), less than 1371.60 m (1500 yards), less than 1143 m (1250 yards), less than 914.40 m (1000 yards), less than 685.80 m (750 yards), less than 457.20 m (500 yards), less than 228.60 m (250 yards), or less than 91.44 m (100 yards) from the waste plastics separation system.

[0253] Furthermore, as with the embodiments described above, the facility 800 for processing plastic solids may include at least a first 824 and a second 834 enclosure structure (see Figure 13 ), configured as described herein and configured to process any of the granular plastic solids streams described herein. However, in one particular embodiment or in combination with any of the mentioned embodiments, the plastic solids facility 800 includes a first enclosed structure 824 configured to receive the polyethylene terephthalate rich stream 820 from the mixed plastic waste separation system 745 within the granular plastic solids facility. The plastic solids facility 800 may also include a second enclosed structure 834 (see Figure 13), which is configured to receive a polyethylene terephthalate-depleted stream 830 from a mixed plastic waste separation system 745 within the granular plastic solids facility 800.

[0254] like Figure 12 As shown, the conveyor system 723 can be used to transport the granular plastic solids from the waste plastic separation system 745 to the plastic solids processing facility 800 and Figure 12 In the illustrated embodiment, an elongated overhead conveyor 825 is shown transporting granular plastic solids into a first enclosed structure 824. The conveyor system 723 may optionally include a transfer tower 780, one or more bridges 790, or other structures necessary or desired for efficient transport of granular plastic solids. The conveying system may be mechanical or pneumatic. The elongated overhead conveyor 825 is configured to selectively deposit a stream of granular plastic solids into a plastic solids transport system 840 and / or at least one granular plastic solids inventory 826 at various locations along the length of the overhead conveyor 825. In one embodiment or in combination with any of the aforementioned embodiments, the overhead conveyor 825 may be located within and / or extend through the interior of the enclosed structure 824. Alternatively, the overhead conveyor 825 may be mounted external to the enclosed structure 824 but provided with one or more chutes, ports, duct sections, etc. communicating with the interior of the structure 824. Thus, two or more granular plastic solids inventory 826 may be stored so as to be arranged in parallel or in series within a single enclosed structure or in adjacent enclosed structures as described above.

[0255] In one embodiment or in combination with any of the aforementioned embodiments, the overhead conveyor 825 extends at least 50%, at least 60%, at least 70%, at least 80%, or at least 90%, or the entire length of the structure 824. In another embodiment or in combination with any of the aforementioned embodiments, the overhead conveyor 825 extends substantially the length of the enclosed structure 824. In yet another embodiment or in combination with any of the aforementioned embodiments, the overhead conveyor 825 extends no more than 95%, no more than 90%, no more than 85%, no more than 80%, no more than 75%, no more than 70%, no more than 65%, or no more than 60% of the length of the enclosed structure 824. The relationship between the length of the conveyor 825 and the length of the enclosed structure 824 can depend on the angle of repose of the amount of particulate plastic solids deposited into the enclosed structure 824 by the conveyor 825. In one such embodiment or in combination with any of the aforementioned embodiments, the length of the conveyor 825 can be substantially the entire length of the enclosed structure 824 minus the distance from the center of the pile 826 to its outermost bottom edge.

[0256] In one embodiment or in combination with any of the aforementioned embodiments, the elongated overhead conveyor 825 can include any type of conveyor described herein, such as a belt conveyor, a pneumatic conveyor, a vibratory conveyor, or a screw conveyor. In a specific embodiment or in combination with any of the aforementioned embodiments, the overhead conveyor 825 includes a belt conveyor that includes one or more movable gates or scrapers disposed along the length of the conveyor that are configured to divert at least a portion of the particulate plastic solids traveling along the conveyor into, for example, a chute that directs the particulate plastic solids to the floor of the enclosed structure to form a pile 826 of particulate plastic solids. In another embodiment or in combination with any of the aforementioned embodiments, the overhead conveyor 825 includes a displaceable member, such as a trip stacker 827, that is configured to traverse at least a portion of the length of the conveyor 825 and divert at least a portion of the particulate plastic solids traveling on the conveyor to the floor of the enclosed structure. The overhead conveyor 825 and the structure for diverting the granular plastic solids can be configured so that the solids are directed at an angle toward the floor of the enclosure so that the peak of the resulting pile 826 is not directly beneath the overhead conveyor 825 .

[0257] As described above, the elongated conveyor 825 is configured to selectively deposit the stream of particulate plastic solids carried thereby into at least one stockpile 826 within the enclosed structure 824. The at least one stockpile 826 can include any amount of particulate plastic solids described herein. The purpose and function of the at least one stockpile 826 are discussed further below, but generally, the at least one stockpile 826 is used when the particulate plastic solids produced by the waste plastic separation system 745 do not fully meet the particulate plastic solids requirements of the downstream plastic chemical recycling process 900.

[0258] In one embodiment or in combination with any of the above embodiments, typically, at least one inventory pile 826 comprises a quantity of polyethylene terephthalate-rich particulate plastic solids (e.g., Figure 12 ) and / or a certain amount of polyethylene terephthalate-depleted particulate plastic solids (not shown). These amounts of particulate plastic solids are generated by waste plastic separation system 745, which can be co-located with plastic solids processing facility 800, although this is not always the case.

[0259] The elongated conveyor 825 is further configured to selectively deposit the granular plastic solids stream carried thereby into a plastic solids transport system 840. In one embodiment or in combination with any of the aforementioned embodiments, the plastic solids transport system includes one or more conveyors that interconnect the plastic solids processing facility 800 and the enclosure 824, specifically with the downstream plastic chemical recycling process 900. The plastic solids transport system 840 may include a first conveyor 822 configured to transport a polyethylene terephthalate rich stream between the granular plastic solids processing facility 800 and the solvolysis facility 920 (see Figure 13 ). The plastic solids transport system 840 may further include a second conveyor 832 configured to transport the polyethylene terephthalate-depleted stream between the plastic solids processing facility 800 and at least one of the partial oxidation gasification facility 930 and the pyrolysis facility 940 (see Figure 13 ).

[0260] In one embodiment or in combination with any of the aforementioned embodiments, the plastic solids transport system 840 includes an apparatus 842 configured to receive granular plastic solids from the plastic solids processing facility 800 and the conveying apparatus 822 for transporting the granular plastic solids to the downstream plastic recycling process 900. The receiving apparatus 842 may include a bin or hopper operably connected to a granular plastic feeder 844, such as a paddle feeder (see Figure 12 ), which initiates transport from the processing facility 800 to the downstream recycling process. A front-end loader 846 or similar mechanism may also be used to load the granular plastic solids into the granular plastic feeder 844. Paddle feeders are distinct from other mechanisms that may also be used to move or load granular plastic solids within the scope of the present technology, including "loss-in-weight" feeders that may include a screw or belt conveyor connected to the bottom of a hopper. The granular plastic feeder 844 then directs the granular plastic solids to a conveying device 822 for transport to the plastic chemical recycling process 900.

[0261] In one embodiment or in combination with any of the mentioned embodiments, the conveying equipment 822 comprises any conveyor suitable for transporting granular plastic solids as described herein. Exemplary conveyors may include pneumatic conveyors, belt conveyors, bucket conveyors, vibratory conveyors, screw conveyors, crawler conveyors, drag conveyors, overhead conveyors, chain conveyors, and trucks. In a specific embodiment or in combination with any of the mentioned embodiments, the conveying equipment 822 comprises a pneumatic conveyor including a pneumatic plastic transport conduit 823 interconnecting the plastic solids processing facility 800 and the plastic chemical recycling facility 900, a blower 821 providing power for transporting granular plastic solids within the conduit 823, and optionally at least one dust collector (not shown), which may be located at or near the distal end of the conduit 823.

[0262] In one embodiment or in combination with any of the mentioned embodiments, the plastics chemical recycling facility 900 includes a solvolysis facility 920, a partial oxidation ("POX") gasifier facility 930, or a pyrolysis facility 940. The plastics chemical recycling facility 900 may also include an energy generation / production facility. The solvolysis facility 920 may include an ester solvolysis facility, such as a methanolysis or a PET solvolysis facility. The plastics solids processing facility 800 may be located less than 1609.34 m (one mile), less than 1371.60 m (1500 yards), less than 1143 m (1250 yards), less than 914.40 m (1000 yards), less than 685.80 m (750 yards), less than 457.20 m (500 yards), less than 228.60 m (250 yards), or less than 91.44 m (100 yards) from the plastics chemical recycling facility 900. In one or more embodiments, the solvolysis facility 920, the POX gasifier 930, and the pyrolysis facility are located less than 3,218.68 m (2 miles), less than 1609.34 m (one mile), less than 1371.60 m (1500 yards), less than 1143 m (1250 yards), less than 914.40 m (1000 yards), less than 685.80 m (750 yards), less than 457.20 m (500 yards), less than 228.60 m (250 yards), or less than 91.44 m (100 yards) from each other.

[0263] Figure 13 An exemplary plastic solids recovery facility is schematically depicted, comprising a waste plastic separation system 745 operable to produce a polyethylene terephthalate (PET)-rich particulate plastic solids stream 820 and a polyethylene terephthalate (PET)-depleted particulate plastic solids stream 830. Each stream is then conveyed to a respective enclosure 824, 834, which may comprise any enclosure described herein configured for handling and processing such streams. In one particular embodiment or in combination with any of the aforementioned embodiments, the enclosure comprises Figure 12 An enclosed structure is depicted in FIG, which includes an overhead conveyor 825 operable to deposit granular plastic solids within the structure or to deposit granular plastic solids within a plastic solids transport system.

[0264] Each enclosed structure 824, 834 is configured to provide a stream of granular plastic solids to at least one respective downstream plastic chemical recycling facility via a granular plastic solids transport system located between the respective structures and the facility. In one embodiment or in combination with any of the aforementioned embodiments, the first enclosed structure 824 is configured to supply the stream of granular plastic solids to a solvolysis process 920, wherein various solvolysis products 922 are produced, including esters, alcohols, and solvolysis byproducts, such as heavy organic solvolysis byproducts and light organic solvolysis byproducts. The PET-rich granular plastic solid stream can be supplied to the PET solvolysis process, wherein various products are produced, including dimethyl terephthalate (DMT), ethylene glycol (EG), methanol, and methanolysis byproducts, such as light organic methanolysis byproducts and / or heavy organic methanolysis byproducts.

[0265] In one embodiment or in combination with any of the aforementioned embodiments, the second enclosed structure 834 is configured to provide a stream of granular plastic solids, particularly a stream lean in polyethylene terephthalate and potentially rich in polyolefins, to at least one of the POX gasifier facility 930, the solvolysis facility 920, or the pyrolysis facility 940 via a second granular plastic solids transport system (e.g., conveyor 832). The POX gasifier facility 930 can be configured to receive solids, optionally in combination with solid fossil fuels such as coal or PET coke (petroleum coke). The POX gasifier facility 930 can be operated to produce syngas 932, optionally producing a syngas stream of a quality suitable for producing chemicals (e.g., methanol or acetyl streams). The pyrolysis facility 940 can be operated to produce various pyrolysis products and by-products, such as pyrolysis gas 942, pyrolysis liquids (e.g., pyrolysis oil) 944, and pyrolysis residues such as pyrolysis heavy wax and pyrolysis coke (not shown). Solvolysis facility 920 can be configured to decompose at least a portion of the plastic solids (typically PET) in the presence of a solvent to form a primarily carboxyl product, such as dimethyl terephthalate, and a primarily glycol product, such as ethylene glycol.

[0266] In one embodiment or in combination with any of the mentioned embodiments, the chemical recovery facility 900 can also include energy generation / production equipment. As used herein, an "energy generation / production facility" is a facility that generates energy (i.e., heat) from a feedstock via chemical conversion (e.g., combustion) of the feedstock.

[0267] Any type of energy generation / production facility can be used. In one embodiment or in combination with any of the mentioned embodiments, the energy generation / production facility 900 can include at least one furnace or incinerator. The incinerator can be gas-fed, liquid-fed, or solid-fed, or can be configured to receive gases, liquids, or solids. In one embodiment or in combination with any of the mentioned embodiments, the incinerator can be configured to receive a combination of solids, gases, and liquids. Specific examples of incinerators or furnaces can include, but are not limited to, rotary kilns and liquid chemical destroyers. The combustion temperature within the furnace or incinerator can be at least 800, at least 825, at least 850, at least 875, or 900°C and / or no more than 1200, no more than 1175, no more than 1150, or no more than 1125°C, or 800 to 1200°C, 850 to about 1150°C, or 900 to 1125°C.

[0268] The incinerator or furnace can be configured to thermally combust at least a portion of the hydrocarbon components in the feed stream with an oxygenant stream. In one embodiment or in combination with any of the aforementioned embodiments, the oxygenant stream comprises at least 5, at least 10, at least 15, at least 20, or at least 25, and / or no more than 70, no more than 65, no more than 60, no more than 55, no more than 50, no more than 45, no more than 40, no more than 35, no more than 30, or no more than 25 mol% oxygen, based on the total moles of the oxygenant stream, or it can comprise an amount in the range of 5 mol% to 70 mol%, 10 mol% to 55 mol%, or 10 mol% to 25 mol%, based on the total moles of the stream. Other components of the oxygenant stream can include, for example, nitrogen or carbon dioxide. In other embodiments, the oxygenant stream comprises air.

[0269] In an energy generation / production facility, at least 50, at least 60, at least 70, at least 80, at least 90, or at least 95 wt% of a feed stream introduced therein can be combusted to form energy and a combustion gas stream, such as water, carbon monoxide, carbon dioxide, and combinations thereof. At least a portion of the feed stream can be treated to remove compounds such as sulfur and / or nitrogen-containing compounds to minimize the amount of nitrogen and sulfur oxides in the combustion gas stream. In one embodiment or in combination with any of the mentioned embodiments, at least a portion of the energy generated by the energy generation / production facility can be used to directly or indirectly heat a process stream. For example, in one embodiment or in combination with any of the mentioned embodiments, at least a portion of the energy can be used to heat water to form steam, and / or to heat steam and form superheated steam. At least a portion of the energy generated can be used to heat a heat transfer medium stream (e.g., ), which, when heated, can itself be used to transfer heat to one or more process streams. At least a portion of the energy can be used to directly heat the process streams.

[0270] Figure 13The plastic solids recovery facility described in the foregoing can be operated in a variety of ways. In one embodiment or in combination with any of the aforementioned embodiments, while the plastic chemical recovery facility 900 is in operation, granular plastic solids are continuously deposited into the granular plastic solids transport system 840. In this mode of operation, granular plastic solids, such as those carried by the overhead conveyor 825, are transported directly to the granular plastic solids transport system 840 without first being placed into the inventory pile 826 within the enclosure 824, 834.

[0271] In one other embodiment or in combination with any of the mentioned embodiments, when the chemical plastics recycling facility 900 is not in operation, the granular plastic solids are stored in at least one stockpile 826. When there is no demand for the granular plastic solids received from the waste plastic separation process 745, the granular plastic solids can be placed in one or more stockpile 826 by diverting the solids carried by the overhead conveyor 825 to the floor of the enclosed structure.

[0272] In another embodiment, or in combination with any of the aforementioned embodiments, while the plastics chemical recycling facility 900 is in operation, granular plastic solids are loaded from at least one stockpile 826 previously formed within the enclosures 824, 834 into the granular plastic solids transport system 840. In some cases, the waste plastic separation process 745 does not produce granular plastic solids, but it is desirable to continue operating the plastics chemical recycling facility 900. Therefore, granular plastic solids are removed from one or more stockpiles 826 within the enclosures 824, 834 and fed into the granular plastic solids transport system 840. This can be accomplished using a front-end loader 846 or a belt loader to deposit the granular plastic solids into a feed bin or hopper of the transport system 840. However, other equipment for accomplishing this operation can also be used. For example, when a front-end loader is used, the granular plastic solids are transported from the at least one stockpile to the granular plastic solids transport system in batches, as opposed to using a belt loader to continuously feed the transport system.

[0273] In one other embodiment or in combination with any of the embodiments mentioned, granular plastic solids are deposited simultaneously from both the overhead conveyor 825 and the at least one stockpile 826 into the granular plastic solids transport system 840. In some cases, the rate of granular plastic solids from the waste plastic separation process 745 is insufficient to supply the entire demand for granular plastic solids at the plastic chemical recycling facility 900. Therefore, granular plastic solids can be deposited directly from the overhead conveyor 825 into the granular plastic solids transport system 840 and removed from the one or more stockpiles 826, as described above.

[0274] Figure 15 An embodiment of a granular plastic solids processing facility 800 is schematically depicted, which is similar in many respects to the embodiment described above with respect to FIG. Figure 12and 13 The granular plastic solids processing facility 800 includes a first enclosed structure 824 configured to receive a polyethylene terephthalate (PET)-rich stream from the mixed plastic waste separation system 745 within the granular plastic solids processing facility. The granular plastic solids processing facility 800 also includes a second enclosed structure 834 configured to receive a PET-depleted stream from the mixed plastic waste separation system 745. According to any embodiment or combination of embodiments described herein, the PET-rich stream and the PET-depleted stream can each contain granular plastic solids.

[0275] like Figure 15 As depicted in FIG, the granular plastic solids processing facility 800 is co-located with the waste plastic separation system 745 and the granular plastic material transported therebetween by the conveyor system. The conveyor system may be any type of conveyor system described herein; however, Figure 15 The conveyor system shown in the figure shows a pneumatic conveyor system.

[0276] The pneumatic conveyor system includes a loader / blower assembly 760 configured to receive granular plastic solids from, for example, a density separation process described above. Assembly 760 is operably connected to a plastic conduit 762. In one embodiment or in combination with any of the embodiments mentioned, granular plastic solids can include an output stream from a mixed plastic waste separation process (e.g., any density separation process described herein) and are transported through conduit 762 under the power provided by assembly 760. Granular plastic solids can contain very fine particles, which may present an explosion hazard. Therefore, granular plastic solids can be directed through one or more plastic densifiers 764, which can soften and aggregate granular plastic solids and form larger particles, such as pellets or granules, having reduced surface area / weight characteristics. The particles produced by densifier 764 can have at least one size greater than 2.54 cm (1 inch), greater than 1.91 cm (0.75 inch), or greater than 1.27 cm (0.5 inch). The pellets produced by densifier 764 may have at least one dimension of 1.27 cm to 25.4 cm, 1.91 cm to 19.1 cm, or 2.54 cm to 12.7 cm. Valve 766 controls the flow of granular plastic solids between conduit 762 and densifier 764. The granular plastic solids exiting densifier 764 may pass through screening device 768 to remove fines remaining in the granular plastic solids flow.

[0277] The particulate plastic solids exiting the mixed plastic waste separation system 745 are then directed to one of the enclosed structures 824, 834, depending on the composition of the transported solids. If the particulate plastic solids comprise a PET-rich stream, that stream is directed to the enclosed structure 824. If the particulate plastic solids comprise a PET-depleted stream, such as an olefin-rich stream, that stream is directed to the enclosed structure 834. One or both of the structures 834 may be equipped with a pneumatic overhead conveyor system comprising a plastic conducting conduit 850 and one or more cyclone separators 852 operably connected to the conduit 850 and operable to deposit at least a portion of the particulate plastic solids entrained within the conduit into one or more particulate plastic solid inventory piles 826. Alternatively, the particulate plastic solids may bypass the cyclone separators 852 and be conveyed to an apparatus configured to remove particulate plastic solids from the enclosed structures 824, 834 (see, e.g., FIG. 1 ). Figure 12 The conduit 850 from each enclosure is also operatively connected to a dust collection device 854, which also includes a blower 856 that provides motive force for conveying the granular plastic solids through the conduit 850. The stockpile 826 or the granular plastic solids that bypass storage in the stockpile according to any embodiment or combination of embodiments described herein can be further processed and handled.

[0278] In one embodiment or in combination with any of the mentioned embodiments, more than one downstream plastic chemical recycling facility is in operation. Thus, particulate plastic solids from at least one of the enclosed structures are used to supply the recycling facility. A first enclosed structure may process or process a stream of particulate plastic solids rich in polyethylene terephthalate and a second enclosed structure may process or process a stream of particulate plastic solids depleted in polyethylene terephthalate. The overhead conveyor associated with each enclosed structure may be configured to deposit the streams of particulate plastic solids simultaneously into a first and a second particulate plastic solid transport system and / or a first and a second stockpile. Thus, within the respective transport systems, the depositing of the polyethylene terephthalate-rich stream occurs simultaneously with the depositing of the polyethylene terephthalate-depleted stream. However, the mode of supply of particulate plastic solids from their respective enclosed structures need not always be the same, and it is contemplated that different modes may be used simultaneously. For example, particulate plastic solids rich in polyethylene terephthalate can be fed directly from an overhead conveyor to a first particulate plastic solids transport system, while particulate plastic solids poor in polyethylene terephthalate can be fed from one or more stockpiles of such solids to a second particulate plastic solids transport system. One closed structure can also deposit particulate plastic solids into one or more stockpiles while another closed structure does not receive any particulate plastic solids from the waste plastic separation process.

[0279] After reviewing the disclosure herein, additional advantages of the various embodiments of the present invention will be readily apparent to those skilled in the art. It should be understood that, unless otherwise indicated herein, the various embodiments described herein are not necessarily mutually exclusive. For example, features described or depicted in one embodiment may also be included in other embodiments, but not necessarily so. Thus, the disclosure provided herein encompasses various combinations and / or integrations of the specific embodiments.

[0280] Examples

[0281] The following example illustrates a method for separating plastic according to one embodiment of the present invention. However, it should be understood that this example is provided by way of illustration and nothing in it should be considered as limiting the overall scope of the present invention.

[0282] In this example, various mixed plastic waste feedstocks were fed into a separation process that included a first high-density float-sink separation stage (target separation density of 1.4 g / cc), followed by a second low-density float-sink separation stage (target separation density of 1.3 g / cc), similar to Figure 4 The process shown in and described above. Potassium carbonate was used to prepare the concentrated brine solution for the float and sink stage. Table 1 below provides the feedstock and product stream compositions for the experiments using different feedstock sources and other waste components with different plastic contents. The heavy enriched stream (i.e., a plastic stream with an average plastic density greater than 1.4 g / cc) is not shown in Table 1 because the recovery of this stream was negligible in these experimental runs. All percentages are given as weight percentages, where the total weight of the feed stream is taken as 100 wt%. Nylon content is provided based on the measured nitrogen (N) atomic weight.

[0283] Table 1.

[0284]

[0285]

[0286] Antimicrobial data for various samples of mixed plastic waste feedstock were also collected to demonstrate that the use of potassium carbonate in the density separation process described above also provides an antimicrobial effect without the need for a separate antimicrobial agent. Samples 1-4 were treated with the potassium carbonate medium used in the aforementioned density separation process. Antimicrobial data for treated and untreated plastics were collected using the test procedures described herein. Bacterial counts were performed using cultures grown on plate count agar (PCA) matrix. Fungal counts were performed using cultures grown on Sabouraud dextrose agar (SDA) matrix. The results are provided in Table 2 below. It can be seen that the density separation process described above is very effective in reducing bacterial and fungal counts in plastics.

[0287] Table 2

[0288]

[0289] definition

[0290] 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, for example, where the context dictates the usage of a defined term.

[0291] As used herein, the terms "a," "an," and "the" mean one or more than one.

[0292] As used herein, the term "and / or," when used in the context of a list of two or more items, means that any one of the listed items can be used alone, or any combination of two or more of the listed items can be used. 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 combination of A and B; a combination of A and C; a combination of B and C; or a combination of A, B, and C.

[0293] As used herein, the term "biowaste" refers to materials derived from living organisms or organic sources. Exemplary biowaste materials include, but are not limited to, cotton, wood, sawdust, food scraps, animals and animal parts, plants and plant parts, and fertilizers.

[0294] As used herein, the term "caustic" refers to any alkaline solution (eg, strong base, concentrated weak base, etc.) that can be used as a cleaning agent in the art for killing pathogens and / or reducing odors.

[0295] As used herein, the term "centrifugal density separation" refers to a density separation process in which the separation of materials is caused primarily by centrifugal forces.

[0296] As used herein, the term "chemical recycling" refers to a waste plastic recycling process that includes the steps of chemically converting waste plastic polymers into lower molecular weight polymers, oligomers, monomers and / or non-polymer molecules (such as hydrogen and carbon monoxide) that are useful themselves and / or serve as feedstock for another chemical production process or processes.

[0297] As used herein, the term "chemical recycling facility" refers to a facility that produces recycled content products by chemically recycling waste plastics. A chemical recycling facility may employ one or more of the following steps: (i) pretreatment, (ii) solvolysis, (iii) pyrolysis, (iv) cracking, and / or (v) POX gasification.

[0298] As used herein, the term "co-located" refers to the characteristic that at least two objects are located in a common physical location and / or are within 1609.34 meters (one mile) of each other.

[0299] As used herein, the term "compatibilizer" refers to an agent that is capable of combining at least two otherwise immiscible polymers in a physical mixture (ie, a blend).

[0300] As used herein, the term "comprising / comprises / comprise" is an open transition term used to transition from the object described before the term to one or more elements described after the term, wherein the one or more elements listed after the transition term are not necessarily the only elements that constitute the object.

[0301] As used herein, the term "conducting" refers to the transport of material in an intermittent and / or continuous manner.

[0302] As used herein, the term "cracking" refers to the decomposition of complex organic molecules into simpler molecules by the breaking of carbon-carbon bonds.

[0303] As used herein, the term "D90" describes the diameter at which 90% of the distribution has smaller particle sizes and 10% has larger particle sizes.

[0304] As used herein, the term "density separation process" refers to a process that separates materials based at least in part on their respective densities. Additionally, the terms "low-density separation stage" and "high-density separation stage" refer to relative density separation processes where the target separation density for the low-density separation is less than the target separation density for the high-density separation stage.

[0305] As used herein, the term "depleted" means that the concentration of a particular component (on a dry basis) is less than the concentration of that component in a reference material or stream.

[0306] As used herein, the term "directly derived" means having at least one physical component derived from waste plastic.

[0307] As used herein, the term "enriched" refers to having a concentration (on a dry basis) of a particular component that is greater than the concentration of that component in a reference material or stream.

[0308] As used herein, the term "halide" refers to a composition comprising a negatively charged halogen atom (ie, a halide ion).

[0309] As used herein, the term "halo" or "halogen" refers to an organic or inorganic compound, ion, or elemental species that contains at least one halogen atom.

[0310] As used herein, the terms "having / has / have" have the same open-ended meaning as "comprising" provided above.

[0311] As used herein, the term "heavy organic methanolysis by-products" refers to methanolysis by-products having a boiling point higher than DMT.

[0312] As used herein, the term "heavy organic solvolysis byproducts" refers to solvolysis byproducts having a boiling point higher than the primary terephthaloyl product of the solvolysis facility.

[0313] As used herein, the terms "including," "includes," and "include" have the same open-ended meaning as "comprising" provided above.

[0314] As used herein, the term "indirectly derived" means having a designated recycled content that is i) attributable to waste plastic but ii) not based on having a physical component derived from waste plastic.

[0315] As used herein, the term "isolated" refers to the characteristic of one or more objects that are inherent and separate from other materials, whether moving or stationary.

[0316] As used herein, the term "light organic methanolysis by-products" refers to methanolysis by-products having a boiling point lower than that of DMT.

[0317] As used herein, the term "light organic solvolysis byproducts" refers to solvolysis byproducts having a boiling point lower than the primary terephthaloyl product of the solvolysis facility.

[0318] As used herein, the term "manufactured cellulosic products" refers to non-natural (ie, man-made or machine-made) articles containing cellulosic fibers and their waste products. Exemplary manufactured cellulosic products include, but are not limited to, paper and paperboard.

[0319] As used herein, the term "methanolysis byproduct" refers to any compound removed from a methanolysis facility that is not dimethyl terephthalate (DMT), ethylene glycol (EG), or methanol.

[0320] As used herein, "mixed plastic waste" or MPW refers to post-industrial (or pre-consumer) plastics, post-consumer plastics, or mixtures thereof. Examples of plastic materials include, but are not limited to, polyester, one or more polyolefins (PO), and polyvinyl chloride (PVC). Furthermore, as used herein, "waste plastic" refers to any post-industrial (or pre-consumer) and post-consumer plastics, such as, but not limited to, polyester, polyolefin (PO), and / or polyvinyl chloride (PVC).

[0321] As used herein, the term "multicomponent polymer" refers to an article and / or particle comprising at least one synthetic or natural polymer combined, attached, or otherwise physically and / or chemically associated with at least one other polymer and / or non-polymeric solid.

[0322] As used herein, the term "multi-layer polymer" refers to a multicomponent polymer comprising PET and at least one other polymeric and / or non-polymeric solid physically and / or chemically associated together in two or more physically distinct phases.

[0323] As used herein, the term "partial oxidation (POX) gasification" or "POX" refers to the high-temperature conversion of a carbonaceous feed to synthesis gas (carbon monoxide, hydrogen, and carbon dioxide), wherein the conversion is carried out in the presence of less than the stoichiometric amount of oxygen required for complete oxidation of the carbon to CO. The feed to the POX gasification may include solids, liquids, and / or gases.

[0324] As used herein, "PET" refers to a homopolymer of polyethylene terephthalate, or polyethylene terephthalate modified with a modifier or containing residues or moieties other than ethylene glycol and terephthalic acid, such as isophthalic acid, diethylene glycol, TMCD (2,2,4,4-tetramethyl-1,3-cyclobutanediol), CHDM (cyclohexanedimethanol), propylene glycol, isosorbide, 1,4-butanediol, 1,3-propanediol, and / or NPG. (neopentyl glycol), or polyesters having repeating terephthalate units (and whether or not they contain repeating ethylene glycol units) and one or more of the following residues or moieties: TMCD (2,2,4,4-tetramethyl-1,3-cyclobutanediol), CHDM (cyclohexanedimethanol), propylene glycol, or NPG (neopentyl glycol), isosorbide, isophthalic acid, 1,4-butanediol, 1,3-propylene glycol and / or diethylene glycol or a combination thereof.

[0325] As used herein, the term "elevated" refers to the physical location of a structure above the maximum height of the amount of particulate plastic solids within the enclosed structure.

[0326] As used herein, the term "partial oxidation (POX) gasification facility" or "POX facility" refers to a facility that includes all equipment, piping, and controls necessary to perform POX gasification of waste plastics and feedstocks derived therefrom.

[0327] As used herein, the term "PET solvolysis" refers to a reaction by which a plastic feed containing poly(terephthalate) is chemically decomposed in the presence of a solvent to form a primarily terephthalyl product and a primarily diol product.

[0328] As used herein, the term "physical recycling" (also known as "mechanical recycling") refers to a waste plastic recycling process that includes the steps of melting the waste plastic and forming the melted plastic into new intermediate products (e.g., pellets or sheets) and / or new end products (e.g., bottles). Typically, physical recycling does not change the chemical structure of the plastic.

[0329] As used herein, the term "primarily" means greater than 50 wt%. For example, a stream, composition, feedstock, or product that is primarily propane is a stream, composition, feedstock, or product that contains greater than 50 wt% propane.

[0330] As used herein, the term "pretreatment" refers to preparing waste plastic for chemical recycling using one or more of the following steps: (i) comminution, (ii) pelletizing, (iii) washing, (iv) drying, and / or (v) separation.

[0331] As used herein, the term "pyrolysis" refers to the thermal decomposition of one or more organic materials at elevated temperatures in an inert (ie, substantially oxygen-free) atmosphere.

[0332] As used herein, the term "pyrolytic coke" refers to a carbonaceous composition obtained from pyrolysis that is solid at 200°C and 1 atm.

[0333] As used herein, the term "pyrolysis gas" refers to a composition obtained from pyrolysis, which is in a gaseous state at 25°C.

[0334] As used herein, the term "pyrolytic heavy wax" refers to C20+ hydrocarbons obtained from pyrolysis that are not pyrolysis coke, pyrolysis gas, or pyrolysis oil.

[0335] As used herein, the term "pyrolysis oil" or "pyoil" refers to a composition obtained from pyrolysis that is liquid at 25°C and 1 atm.

[0336] As used herein, the term "pyrolysis residue" refers to a composition obtained from pyrolysis that is not pyrolysis gas or pyrolysis oil and primarily comprises pyrolysis coke and pyrolysis heavy wax.

[0337] As used herein, the term "recycled content" refers to a composition or a composition comprising a composition that is directly and / or indirectly derived from waste plastic.

[0338] As used herein, the term "separation efficiency" refers to Figure 14 , Figure 14Shown are a separator 950, a feedstock 960 (comprising a light density component (A), a medium density component (B), and a high density component (C)), a product stream 970 (for the light density component (A)), and a product stream 980 (for the medium density component (B) and the high density component (C),

[0339] With respect to the product stream 970 (per unit time):

[0340] Product efficiency A =A product weight / A feed rate;

[0341] Pollution efficiency B = weight of product of B / feed rate of B;

[0342] Pollution efficiency C = weight of product of C / feed rate of C;

[0343] Product purity A = weight of product of A / (product rate of A+B+C),

[0344] And wherein with respect to the product stream 980 (per unit time):

[0345] Pollution efficiency A =A product weight / A feed rate;

[0346] Product efficiency B = weight of product of B / feed rate of B;

[0347] Product efficiency C = weight of product of C / feed rate of C;

[0348] Product purity = (product weight of B + C) / (product rate of A + B + C).

[0349] As used herein, the term "float-sink density separation" refers to a density separation process in which the separation of materials is primarily caused by floating or sinking in a selected liquid medium.

[0350] As used herein, the term "solvolysis" or "ester solvolysis" refers to a reaction in which an ester-containing feed chemically decomposes in the presence of a solvent to form a major carboxyl product and a major diol product. Examples of solvolysis include hydrolysis, alcoholysis, and aminolysis.

[0351] As used herein, the term "solvolysis byproduct" refers to any compound removed from a solvolysis facility that is not the primary carboxyl (primarily terephthaloyl) product of the solvolysis facility, the primary diol product of the solvolysis facility, or the primary solvent fed to the solvolysis facility.

[0352] As used herein, the term "terephthaloyl" refers to a molecule that includes the following groups:

[0353]

[0354] As used herein, the term "primarily terephthalyl" refers to the primary or key terephthalyl product extracted from a solvolysis facility.

[0355] As used herein, the term "diol" refers to a composition comprising two or more -OH functional groups per molecule.

[0356] As used herein, the term "primary diol" refers to the primary diol product extracted from a solvolysis facility.

[0357] As used herein, the term "target separation density" refers to the density above which materials undergoing a density separation process preferentially separate into a higher density output, and below which materials separate into a lower density output. The target separation density specifies a density value above which all plastics and other solid materials with a density greater than this value separate into a higher density output, and below which all plastics and other solid materials separate into a lower density output. However, the actual separation efficiency of a material during a density separation process can depend on various factors, including residence time and how close the density of a particular material is to the target density separation value.

[0358] As used herein, the term "waste plastic" refers to used, discarded and / or discarded plastic materials, such as polyethylene terephthalate (PET), polyolefins (PO) and / or polyvinyl chloride (PVC). The waste plastic may also include some minor plastic components, the total weight of which is less than 10% of the waste plastic content and which individually account for less than 1% of the waste plastic content. In one or more embodiments, the waste plastic may also include some minor plastic components (excluding PET and polyolefins), the total amount of which is less than 50, less than 40, less than 30, less than 20, less than 15 or less than 10 wt% of the total waste plastic, and optionally may individually represent less than 30, less than 20, less than 15, less than 10 or less than 1 wt% of the total waste plastic.

[0359] 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.

[0360] As used herein, "downstream" refers to a target unit operation, vessel, or equipment:

[0361] a. In fluid communication or piped communication with an outlet stream (liquid or gaseous) from the radiant section of a cracker furnace, optionally via one or more intermediate unit operations, vessels or apparatus, or

[0362] b. Be in fluid communication or pipe communication with an outlet stream (liquid or gas) 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 boundaries of the cracker facility (including the furnace and all associated downstream separation equipment).

[0363] The claims are not limited to the disclosed embodiments

[0364] The preferred forms of the invention described above are for illustration only and should not be used in a limiting sense to interpret the scope of the present invention. Those skilled in the art can easily modify the above exemplary embodiments without departing from the spirit of the present invention.

[0365] The inventors hereby declare that they intend to rely on the Doctrine of Equivalents to determine and assess the fair and equitable scope of the invention as it relates to any arrangements that do not materially depart from but fall outside the literal scope of the invention as set forth in the following claims.

Claims

1. A method for treating particulate plastic solids separated from mixed plastic waste, the method comprising: loading said granulated plastic solids received from the mixed plastic waste separation system onto an elongated overhead conveyor associated with the enclosed structure; transporting said particulate plastic solids along the length of said enclosed structure with said elongated overhead conveyor; and selectively depositing the particulate plastic solids from the elongated overhead conveyor into at least one particulate plastic solids inventory pile within the enclosed structure at one or more locations along the length of the elongated overhead conveyor, The granular plastic solids stored therein have the same composition as the granular plastic solids loaded onto the elongated overhead conveyor, and the granular plastic solids have a microbial content of less than 10 9 CFU / g, Method for treating particulate plastic solids separated from mixed plastic waste without applying an antimicrobial agent to the said method, The separation of the mixed plastic waste comprises the use of one or more density separation stages, wherein the liquid medium used in the one or more density separation stages comprises potassium carbonate and / or caustic solution.

2. The method of claim 1 , wherein the particulate plastic solids comprise one of a PET-rich stream and a PET-depleted stream generated by the mixed plastic waste separation system.

3. The method of claim 2, wherein the particulate plastic solids comprise a PET-rich stream comprising greater than 70 wt% polyethylene terephthalate and (a) 0.1 wt% to 4 wt% of halogen, and the microbial content is less than 10% of the plastic solid 9 CFU / g; or (b) 0.1 wt% to 4 wt% of polyvinyl chloride, and at least 0.1 wt% of a solid material that does not undergo a phase change below 270°C and 1 atm; or (c) 0.1 wt% to 4 wt% of halogen; or (d) 0.1 wt% to 10 wt% polyvinyl chloride, and a moisture content of less than 4 wt%; or (e) a nylon content not exceeding 1% by weight; or (f) A multilayer plastic content of no more than 10 wt%.

4. A method according to claim 2, wherein the granular plastic solids from the slender overhead conveyor and / or from the at least one granular plastic solid inventory pile are deposited into the granular plastic solid transport system and transported from the enclosed structure to a plastic chemical recycling facility, the plastic chemical recycling facility comprising at least one of a solvent decomposition facility, a POX gasifier facility, an energy generation / production facility and a pyrolysis facility.

5. The method of claim 4, wherein the plastic chemical recycling facility is located within 1609.34 m of the enclosed structure.

6. The method of claim 4, wherein the particulate plastic solids are deposited into the at least one stockpile while the plastics chemical recycling facility is in operation.

7. The method of claim 4, wherein the particulate plastic solids are deposited into the particulate plastic solids transport system simultaneously from the elongated overhead conveyor and from the at least one inventory pile.

8. The method of claim 1, wherein the pH of the caustic solution is greater than 8.

9. The method of claim 1, wherein the caustic solution comprises a hydroxide.

10. The method according to claim 9, wherein the hydroxide is sodium hydroxide or potassium hydroxide.

11. A method of processing a polyethylene terephthalate (PET)-rich solids stream and a PET-depleted solids stream received from a mixed plastic waste separation system, comprising: loading the PET-rich solids stream onto a first elongated conveyor associated with a first enclosed structure, the first elongated conveyor being located at an elevated position within the first enclosed structure; transporting the PET-rich solids stream within the first enclosed structure using the first elongated conveyor; selectively depositing the stream of PET-rich solids into at least one PET-rich solids inventory pile within the first enclosure at one or more locations along the length of the first elongated conveyor; loading the PET-depleted solids stream onto a second elongated conveyor located within a second enclosed structure, the second elongated conveyor being located at an elevated position within the second enclosed structure and extending substantially the length thereof; transporting the PET-depleted solids stream within the second enclosed structure using the second elongated conveyor; and selectively depositing the stream of PET-depleted solids into at least one PET-depleted solids inventory within the second enclosure at one or more locations along the length of the second elongated conveyor, The PET-rich solid stream contains more than 70 wt% polyethylene terephthalate and 0.1 wt% to 4 wt% halogen and has a microbial content of less than 10 9 CFU / g, without applying an antimicrobial agent to the method of treating particulate plastic solids separated from mixed plastic waste, The separation of the mixed plastic waste comprises the use of one or more density separation stages, wherein the liquid medium used in the one or more density separation stages comprises potassium carbonate and / or caustic solution.

12. The method of claim 11, wherein said storing of said PET-rich stream occurs simultaneously with said storing of said PET-depleted stream.

13. The method of claim 11, wherein at least one of the PET-rich solids and PET-depleted solids transport systems comprises a hopper and a pneumatic plastic delivery conduit.

14. The method according to claim 11, wherein PET-rich solids from the PET-rich solids stream and / or the PET-rich solids inventory pile are deposited into the PET-rich first particulate plastic solids transport system and transported from the first enclosed structure to a solvent decomposition facility located within 1609.34 m of the first enclosed structure.

15. The method according to claim 11, wherein PET-depleted solids from the PET-depleted solids stream and / or the PET-depleted solids inventory are deposited into the PET-depleted solids transport system and transported from the second enclosure to at least one of a POX gasifier facility, an energy generation / production facility, and a pyrolysis facility.

16. The method of claim 11, wherein the storage mode of the PET-rich stream is different from the storage mode of the PET-depleted stream.

17. The method of claim 11, wherein the pH of the caustic solution is greater than 8.

18. The method of claim 11, wherein the caustic solution comprises a hydroxide.

19. The method of claim 18, wherein the hydroxide is sodium hydroxide or potassium hydroxide.

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