Process to remove contaminants from mixed plastic waste

Abstract

Methods of removing contaminants from a mixed plastic waste. A method can include heating and mixing a mixed plastic waste and a solvent to move contaminants from the mixed plastic waste into the solvent and produce a partially depolymerized oligomer from polymeric material from the mixed plastic waste. The partially depolymerized oligomer can be separated from the solvent containing the contaminants. The partially depolymerized oligomer may form particles, such as solid particles with an average particle size of less than 10 mm. The partially depolymerized oligomer may include less contaminants when compared with the mixed plastic waste prior to heating and mixing with the solvent.

Description

23T&I0046-WO-ORD 1PROCESS TO REMOVE CONTAMINANTS FROM MIXED PLASTIC WASTETechnical Field

[0001] The invention generally concerns methods of removing contaminants from a mixed plastic waste. A method can include reacting a mixed plastic waste in a solvent to obtain a partially depolymerized oligomer products from polymeric material of the mixed plastic waste. The solvent and the mixed plastic waste may form two separate phases, a first phase containing the mixed plastic waste and a second phase containing the solvent. The reacting and mixing disperses polymeric material of the mixed plastic waste into the second phase and forms partially depolymerized oligomer products. At least a portion of one or more contaminants contained in the plastic waste stream is moved into the second phase. The partially depolymerized oligomer products can be recovered and can include less contaminants when compared with the mixed plastic waste prior to reacting the mixed plastic waste to produce the partially depolymerized oligomer products.Background Art

[0002] Mixed plastic waste can originate from domestic and / or industrial sources. The composition of mixed plastic waste can include many types of plastic. For example, polyethylene terephthalate (PET), low-density or high-density polyethylene (PE), polypropylene (PP), polyvinyl chloride (PVC), polystyrene (PS), and other miscellaneous plastics coming from a variety of postconsumer products (e.g., electronic waste, automobile waste, polyurethane foam packaging, carpet nylon, and the like). Impurities such as trace metals as compounding additives to enhance performance from polymerization processes can also exist in mixed plastic waste. In addition, small amounts of non-plastics such as paper, wood, and / or food residue can be present.

[0003] Mixed plastic waste can be difficult to recycle, reuse, or discard in an environmentally friendly way. Some of the plastic waste streams are unsuitable for mechanical recycling due to contamination from heteroatoms (chlorine, inorganic components, etc.). Most of the processes for chemical recycling of mixed plastic waste convert it into a hydrocarbon liquid that can be used as feed to some of the petrochemical processes like cracking. However, the conversion of the mixed23T&I0046-WO-ORD 2plastic waste to liquids also produces gas, which are mostly lost, lowering the carbon recovery from mixed plastic waste.

[0004] Pyrolysis of waste mixed plastics is a process that includes decomposing plastics at a high temperature to produce a pyoil. Pyoil can be used directly as a liquid fuel or further processed for producing chemicals of high value. However, pyoil produced from mixed plastics generally contains a substantial amount of highly reactive chemicals, resulting in fast aging of the pyoil and / or formation of gums during transportation and further processing steps. Hence, it is fairly common for pyoil to foul containers and / or chemical processing units in which it is handled and / or processed with trace oxygen present therein. Not all plastics are suitable for pyrolysis processing. For example, PVC can contain as much as 57% chlorine. Conversion of chlorinated polymers can be undesirable due to the chloride derivatives formed that can harm downstream process metallurgy if left untreated. To remove plastics that contain chlorinated products, a sorting mechanism can be applied prior to pyrolysis processes. However, sorting can be inefficient and costly.

[0005] Processes that describe removal of contaminants, such as chloride, from mixed plastic waste have been described. For example, U.S. Patent Application Publication No. 2022 / 0010213 to Sun et al., describes a process for pyrolysis of a mixed plastic stream that includes PVC. The process removes the chloride in a vapor reactor in the initial melting reactor. In another example, Japanese Patent Application No. JP2003231886 to Takeyoshi et al., describes a thermal decomposition process of waste plastic containing oil that suppresses generation of organic volatile substances and evaporates chlorine contained in the mixed plastic waste. In yet another example, International Application Publication No. WO 2021 / 087059 to Wu etal, describes dehalogenating a mixed waste plastic feed by heating the plastic-containing feed to a temperature sufficient to release a halogen-containing waste stream and then pyrolyzing the dehalogenated feed.

[0006] While methods for removing contaminants from mixed plastic waste exist, the need for improvements in this field persists.23T&I0046-WO-ORD 3SUMMARY OF THE INVENTION

[0007] A solution to at least one of the problems associated with contaminant removal from mixed plastic waste has been discovered. The carbon recovery from mixed plastic waste can be enhanced by partially breaking down the polymers to lower molecular weight oligomers instead of hydrocarbon liquids, thereby minimizing the overall gas yield. These oligomers in solid powder form at room temperature are relatively easy to handle and can be fed directly to certain petrochemical operations. The solution herein produces decontaminated oligomers (such as removing chlorine, metals and, other inorganic components in the mixed plastic waste), that increases the value of the product and reduces or avoids having to blend the product with other plastics (e.g., virgin plastics) so that the product is suitable for downstream processes. The process can decontaminate mixed plastic waste without or with minimal or controlled reduction of the molecular weight of the plastics in the mixed plastic waste and can do so with efficient heat and mass transfer.

[0008] In some aspects, a method of the present invention can include providing a plastic waste stream and a solvent to a reactor. The plastic waste stream and the solvent may form a reactor mixture. The solvent may be a solvent that would cause two phases to be produced when combined with a plastic waste stream, a first phase containing at least a portion of the plastic waste stream and a second phase containing the solvent. The reactor in some aspects can have a mixing capability. The reactor in some aspects can have a mixer. In some instances, the mixer has high shear mixing capability. The mixing capability may be provided by one or more of the following non-limiting examples, a pitched blade turbine (PBT), a helical ribbon impeller, a combination of PBT and helical ribbon impeller, a hydrofoil impeller, a rushton turbine, a sawtooth disc impeller, a rotor-stator, a static mixer, an agitated vessel, a colloid mill, a liquid whistle, a valve homogenizer, ultrasonication, an agitator, a closed rotor, a sawtooth blade, microfluidics, etc.. In some aspects, the mixer can be fixed to the reactor. In some aspects, the mixer may be removable from the reactor. In some aspects, the reactor comprises a reactor that moves to mix the reactor mixture. The reaction may occur under mixing to produce particles with a mean average diameter of 500 micrometers or less, 400 micrometers or less, 300 micrometers or less, 200 micrometers or less, 150 micrometers or less, 100 micrometers or less, 75 micrometers or less, or 50 micrometers or less. The plastic waste stream and the solvent may be mixed and the mixture reacted at a23T&I0046-WO-ORD 4temperature and pressure to disperse polymeric material of the plastic waste stream into the second phase containing the solvent. The reaction and mixing may also partially depolymerize the polymeric material to produce a partially depolymerized oligomer. The reaction conditions (temperature, pressure, and / or residence time) can be controlled to achieve a desired molecular weight distribution in the oligomer products (such as for advanced recycling applications) or the polymer chain breakdown of polyolefins can be completely avoided while decontaminating the mixed plastic waste stream (such as for mechanical recycling applications). The reaction and mixing may also move a portion of contaminants from the plastic waste stream into the solvent. The partially depolymerized oligomer may be recovered from the reaction product and separated from at least a portion of the contaminants from the plastic waste stream that moved into the solvent.

[0009] The reaction conditions include temperatures that are preferably below the critical temperature of the solvent for the given pressure. In some aspects, the temperature is at or below 380 °C. In some aspects, the temperature is at or above 250 °C. In some aspects, the temperature is at, greater than, less than, or between 250, 251, 252, 253, 254, 255, 256, 257, 258, 259, 260, 261, 262, 263, 264, 265, 266, 267, 268, 269, 270, 271, 272, 273, 274, 275, 276, 277, 278, 279, 280, 281, 282, 283, 284, 285, 286, 287, 288, 289, 290, 291, 292, 293, 294, 295, 296, 297, 298, 299, 300, 301, 302, 303, 304, 305, 306, 307, 308, 309, 310, 311, 312, 313, 314, 315, 316, 317, 318, 319, 320, 321, 322, 323, 324, 325, 326, 327, 328, 329, 330, 331, 332, 333, 334, 335, 336, 337, 338, 339, 340, 341, 342, 343, 344, 345, 346, 347, 348, 349, 350, 351, 352, 353, 354, 355, 356, 357, 358, 359, 360, 361, 362, 363, 364, 365, 366, 367, 368, 369, 370, 371, 372, 373, 374, 375, 376, 377, 378, 379, or 380 °C, or any range thereof. The reaction conditions may include pressures that are greater than atmospheric pressure. In some aspects, the pressure in the reaction conditions is at or above 50 bar. In some aspects, the pressure in the reaction conditions is at or below 200 bar. In some aspects, the pressure is at, greater than, less than, or between 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, 100, 101, 102, 103, 104, 105, 106, 107, 108, 109, 110, 111, 112, 113, 114, 115, 116, 117, 118, 119, 120, 121, 122, 123, 124, 125, 126, 127, 128, 129, 130, 131, 132, 133, 134, 135, 136, 137, 138, 139, 140, 141, 142, 143, 144, 145, 146, 147, 148, 149, 150, 151, 152, 153, 154, 155, 156, 157, 158, 159, 160, 161, 162, 163, 164, 165, 166, 167, 168, 169, 170, 171, 172, 173, 174, 175, 176, 177, 178, 179,23T&I0046-WO-ORD 5180, 181, 182, 183, 184, 185, 186, 187, 188, 189, 190, 191, 192, 193, 194, 195, 196, 197, 198, 199, or 200 bar, or any range thereof. The reaction conditions may cause hydrogenation of polymeric material with or without the presence of a catalyst. Such hydrogenation may minimize the reaction of olefins with HC1 that may be released during decomposition of chlorinated polymers, this may reduce the production of organic chlorides in the product oligomers. In some aspects, the reaction conditions do not cause hydrogenation of the polymeric material and / or the partially depolymerized oligomer products. The reaction conditions (temperature, pressure, and / or residence time) can be controlled to achieve a desired molecular weight distribution in the oligomer products (such as for advanced recycling applications) or the polymer chain breakdown of polyolefins can be completely avoided while decontaminating the mixed plastic waste stream (such as for mechanical recycling applications).

[0010] The plastic waste stream may be a mixed plastic waste stream that contains more than one type of plastic. The plastic waste stream may in some aspects be a plastic waste stream from electronic waste, automobile waste, polyurethane foam packaging, carpet nylon, etc., or from a combination of industries. The plastic waste stream may in some aspects contain polyethylene terephthalate (PET), low-density or high-density polyethylene (PE), polypropylene (PP), polyvinyl chloride (PVC), polystyrene (PS), polyvinylidene chloride (PVDC), chlorinated polyethylene (CPE), chlorosulphonated polyethylene (CSM), chloroendic acid polyester, or a combination thereof. In some aspects, the plastic waste stream may contain chlorinated polymers, such as polyvinyl chloride (PVC), polyvinylidene chloride (PVDC), chlorinated polyethylene (CPE), chlorosulphonated polyethylene (CSM), chloroendic acid polyester, or a combination thereof. The plastic waste stream may in some aspects contain one or multiple contaminants. The contaminants may include heteroatoms, such as halogens such as chlorine (e.g., chlorides), oxygen (e.g., oxygenates), nitrogen (e.g., nitrates), metals such as sodium (Na), titanium (Ti), calcium (Ca), silicon (Si), potassium (K), iron (Fe), nickel (Ni), and / or aluminum (Al) etc., such as in the form of metal oxides, metal carbonates, etc., or combinations thereof. Contaminants may come from fillers or additives. Additives may include dyes, antioxidants, flame retardants etc. The solvent may be a polar solvent, such as water, a polar inorganic compound, or a polar organic compound. In some instances the solvent is water, NaOH, and / or hexadecane. The solvent may be a combination of solvents, such as an aqueous organic solvent.23T&I0046-WO-ORD 6

[0011] Recovery of the partially depolymerized oligomer may include cooling the reaction product mixture so that the partially depolymerized oligomers solidify. The cooling may occur in the reactor. The cooling may occur under mixing conditions. In some instances, the cooling may occur under high shear mixing conditions. The cooling may occur under mixing to produce particles with a mean average diameter of 500 micrometers or less, 450 micrometers or less, 400 micrometers or less, 350 micrometers or less, 300 micrometers or less, 250 micrometers or less, 200 micrometers or less, 150 micrometers or less, 100 micrometers or less, 75 micrometers or less, or 50 micrometers or less. The cooling may occur after the reaction product is moved out of the reactor. The cooling may occur in a heat exchanger. The solidified partially depolymerized oligomer may be removed from the liquid components, such as the partially depolymerized oligomer is separated from all or a portion of the solvent containing contaminants from the plastic waste stream that moved into the solvent. In some aspects, the solidified partially depolymerized oligomer may be removed by filtration, centrifugation, a cyclone separation, etc., or a combination thereof.

[0012] In some aspects, the plastic waste stream is in the form of particles and / or a liquid, such as a plastic waste stream melt, when contacted with the solvent. In some aspects, the plastic waste stream is in the form of solid particles, such as a powder. In some aspects, the plastic waste stream is in the form of a plastic waste stream melt. The plastic waste stream in the form of a plastic waste stream melt may, in some instances, form particles in the solvent, such as particles being formed by the agitating (e.g., mixing) action of the reaction unit. In some aspects, the plastic waste stream is in the form of a plastic waste stream melt and is in the form of particles before contacting the solvent, such as powder, droplets, or by extrusion and die cutting of the extrudate. In some aspects, the plastic waste stream is not extruded before contacting the solvent. In some aspects, the reaction occurs under conditions that prevent or reduce the formation of agglomerates (e.g., avoid agglomeration) of the plastic waste stream, the particles, and / or the molten plastic waste stream. In some aspects, the reaction occurs under conditions that suspend at least a portion of the polymeric material of the plastic waste stream in the solvent. The particles may be solid or nonsolid particles. The particles may be microparticles and / or nanoparticles. In some aspects, the particles have a mean diameter of less than 500 micrometers. In some aspects, the particles have a mean diameter of at, greater than, less than, between 1, 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 110, 120, 130, 140, 150, 160, 170, 180, 190, 200, 210, 220, 230, 240, 250, 260, 270, 280, 290, 300,23T&I0046-WO-ORD 7310, 320, 330, 340, 350, 360, 370, 380, 390, 400, 410, 420, 430, 440, 450, 460, 470, 480, 490, 500, 510, 520, 530, 540, 550, 560, 570, 580, 590, 600, 610, 620, 630, 640, 650, 660, 670, 680, 690, 700, 710, 720, 730, 740, 750, 760, 770, 780, 790, 800, 810, 820, 830, 840, 850, 860, 870, 880, 890, 900, 910, 920, 930, 940, 950, 960, 970, 980, or 990 nm or 1, 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 110, 120, 130, 140, 150, 160, 170, 180, 190, 200, 210, 220, 230, 240, 250, 260, 270, 280, 290, 300, 310, 320, 330, 340, 350, 360, 370, 380, 390, 400, 410, 420, 430, 440, 450, 460, 470, 480, 490, or 500 micrometer, or any range thereof. In some instances, the particles have a mean diameter of 200 micrometers or less, 150 micrometers or less, 100 micrometers or less, 75 micrometers or less, or 50 micrometers or less.

[0013] In some aspects, the partially depolymerized oligomers produced are at least partially located in the second phase comprising the solvent before being recovered from the reaction product mixture. The partially depolymerized oligomers may be in the form of particles or a liquid. The particles may be solid or non-solid particles. The particles may be microparticles and / or nanoparticles. In some aspects, the particles have a mean diameter of less than 10 micrometers. In some aspects, the particles have a mean diameter of at, greater than, less than, between 1, 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 110, 120, 130, 140, 150, 160, 170, 180, 190, 200, 210, 220, 230, 240, 250, 260, 270, 280, 290, 300, 310, 320, 330, 340, 350, 360, 370, 380, 390, 400, 410, 420, 430, 440, 450, 460, 470, 480, 490, 500, 510, 520, 530, 540, 550, 560, 570, 580, 590, 600, 610, 620, 630, 640, 650, 660, 670, 680, 690, 700, 710, 720, 730, 740, 750, 760, 770, 780, 790, 800, 810, 820, 830, 840, 850, 860, 870, 880, 890, 900, 910, 920, 930, 940, 950, 960, 970, 980, or 990 nm or 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10 micrometer, or any range thereof. In some instances, the particles have a mean diameter of 500 micrometers or less, 400 micrometers or less, 300 micrometers or less, 200 micrometers or less, 150 micrometers or less, 100 micrometers or less, 75 micrometers or less, or 50 micrometers or less. In some aspects, the partially depolymerized oligomers have an average MW of less than 20,000 g / mol. In some aspects, the particles have an average MW of at, greater than, less than, or between 100, 200, 300, 400, 500, 600, 700, 800, 900, 1000, 1100, 1200, 1300, 1400, 1500, 1600, 1700, 1800, 1900, 2000, 2100, 2200, 2300, 2400, 2500, 2600, 2700, 2800, 2900, 3000, 3100, 3200, 3300, 3400, 3500, 3600, 3700, 3800, 3900, 4000, 4100, 4200, 4300, 4400, 4500, 4600, 4700, 4800, 4900, 5000, 5100, 5200, 5300, 5400, 5500, 5600, 5700, 5800, 5900, 6000, 6100, 6200, 6300, 6400, 6500, 6600, 6700, 6800, 6900, 7000, 7100, 7200, 7300, 7400, 7500, 7600, 7700, 7800, 7900, 8000, 8100, 8200, 8300, 8400, 8500, 8600, 8700, 8800, 8900, 9000, 9100, 9200,23T&I0046-WO-ORD 89300, 9400, 9500, 9600, 9700, 9800, 9900, 10000, 11000, 12000, 13000, 14000, 15000, 16000, 17000, 18000, 19000, or 20000 g / mol, or any range thereof. In some aspects, the partially depolymerized oligomers can be further processed to remove insoluble materials, soluble organic materials, inorganic chloride, or a combination thereof, by way of filtration, centrifugation, decanting / sedimentation, and / or washing with water or caustic solution.

[0014] The solvent may be a single solvent, a combination of solvents, and / or may contain additional components. In some aspects, the combination of solvents includes polar and / or nonpolar solvents. Some non-limiting examples of solvents include water, alkaline solutions, and alkane hydrocarbons, such as straight-chain alkane hydrocarbons such as hexadecane, or combinations thereof. In some instances, the solvent is a polar solvent. In some instances, the solvent is water. In some instances, the solvent has a pH above 7, such as at, greater than, less than or between 7.5, 8, 8.5, 9, 9.5, 10, 10.5, 11, 11.5, 12, 12.5, 13, 13.5, or 14 pH, or any range thereof. In some instances, the solvent includes NaOH, sodium bicarbonate, sodium carbonate, potassium hydroxide, or other alkaline compounds. In some instances, the solvent includes NaOH, such as 0. IN NaOH, or at, greater than, less than or between 0.01, 0.02, 0.03, 0.04, 0.05, 0.06, 0.07, 0.08, 0.09, 0.1, 0.11, 0.12, 0.13, 0.14, 0.15, 0.16, 0.17, 0.18, 0.19, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20 N NaOH, or any range thereof. In some aspects, the nonpolar solvents include organic solvents. In some aspects, the polar solvents include organic solvents. In some aspects, the polar solvents include inorganic solvents. In some aspects, the non-polar solvents include inorganic solvents. In some aspects, the solvent, or a solvent comprised in the solvent, is miscible with at least a portion of the plastic in the plastic waste stream, such as a non-polar organic solvent. In some aspects, additional components in the solvent include dissolved or solid salts, dispersing agents such as surfactants to help with dispersion of polymers in the solvent, acids, bases such as NaOH, and / or buffers. A solvent may be used in the combination of solvents at ratios by volume to another solvent at 1000: 1 to 1 : 1000. The solvent may be used in the combination of solvents at ratios by volume to another solvent at, greater than, less than, or between 1000:1, 990:1, 980:1, 970:1, 960:1, 950:1, 940:1, 930:1, 920:1, 910:1, 900:1, 890:1, 880:1, 870:1, 860:1, 850:1, 840:1, 830:1, 820:1, 810:1, 800:1, 790:1, 780:1, 770:1, 760:1, 750:1, 740:1, 730:1, 720:1, 710:1, 700:1, 690:1, 680:1, 670:1, 660:1, 650:1, 640:1, 630:1, 620:1, 610:1, 600:1, 590:1, 580:1, 570:1, 560:1, 550:1, 540:1, 530:1, 520:1, 510:1, 500:1, 490:1, 480:1, 470:1, 460:1, 450:1, 440:1, 430:1, 420:1, 410:1, 400:1, 390:1, 380:1, 370:1, 360:1,23T&I0046-WO-ORD 9350:1, 340:1, 330:1, 320:1, 310:1, 300:1, 290:1, 280:1, 270:1, 260:1, 250:1, 240:1, 230:1, 220:1, 210:1, 200:1, 190:1, 180:1, 170:1, 160:1, 150:1, 140:1, 130:1, 120:1, 110:1, 100:1, 90:1, 80:1, 70:1, 60:1, 50:1, 40:1, 30:1, 20:1, 10:1, 9:1, 8:1, 7:1, 6:1, 5:1, 4:1, 3:1, 2:1, 1:1, 2:1, 3:1, 4:1, 5:1, 6:1, 7:1, 8:1, 9:1, 10:1, 20:1, 30:1, 40:1, 50:1, 60:1, 70:1, 80:1, 90:1, 100:1, 110:1, 120:1, 130:1, 140:1, 150:1, 160:1, 170:1, 180:1, 190:1, 200:1, 210:1, 220:1, 230:1, 240:1, 250:1, 260:1, 270:1, 280:1, 290:1, 300:1, 310:1, 320:1, 330:1, 340:1, 350:1, 360:1, 370:1, 380:1, 390:1, 400:1, 410:1, 420:1, 430:1, 440:1, 450:1, 460:1, 470:1, 480:1, 490:1, 500:1, 510:1, 520:1, 530:1, 540:1, 550:1, 560:1, 570:1, 580:1, 590:1, 600:1, 610:1, 620:1, 630:1, 640:1, 650:1, 660:1, 670:1, 680:1, 690:1, 700:1, 710:1, 720:1, 730:1, 740:1, 750:1, 760:1, 770:1, 780:1, 790:1, 800:1, 810:1, 820:1, 830:1, 840:1, 850:1, 860:1, 870:1, 880:1, 890:1, 900:1, 910:1, 920:1, 930:1, 940:1, 950:1, 960:1, 970:1, 980:1, 990:1, or 1000:1, or any range thereof. In some aspects, an organic solvent, such as hexadecane, is present in the solvent at a percent volume of 0.1 to 99.9 %. In some aspects, an organic solvent, such as hexadecane, is present in the solvent at a percent volume at, greater than, less than, or between 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, 99.1, 99.2, 99.3, 99.4, 99.5, 99.6, 99.7, 99.8, or 99.9 % by volume, or any range thereof. In some aspects, water is present in the solvent at a percent volume of 0.1 to 100 %. In some aspects, water is present in the solvent at a percent volume at, greater than, less than, or between 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, 99.1, 99.2, 99.3, 99.4, 99.5, 99.6, 99.7, 99.8, 99.9, 100 % by volume, or any range thereof.

[0015] In some aspects, depolymerizing the polymeric material to produce a partially depolymerized oligomer releases chlorine from the polymeric material, such as the release of HC1. In some aspects, the plastic waste stream includes chlorinated hydrocarbons. In some aspects, the solvent includes HC1. In some aspects, the HC1 and / or other contaminants are trapped (e.g., by absorption, adsorption, encapsulation, chelation, etc.) by other components in the solvent. The23T&I0046-WO-ORD 10other components that trap may include metal oxides, metal hydroxides, a hydroxide, etc. The components that trap may be present in the plastic waste feed before contacting the mixed plastic waste with the solvent and / or may be present in the solvent before contacting the plastic waste feed, and / or may be added to the plastic waste feed and solvent mixture. In some aspects, at least a portion of the HC1 and / or contaminants released can be in a gas phase and / or a liquid phase.

[0016] In some aspects, the reaction occurs for a time from 2 minutes to 24 hours. In some aspects, the reaction occurs from 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, or 59 minutes, or 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, or 24 hours, or any range thereof.

[0017] In some aspects, the temperature, pressure, reaction time, mixing method, and / or solvent may be adjusted to better obtain the desired products and / or to better remove contaminants from the plastic waste stream to be cleaned.

[0018] Other embodiments of the invention are discussed throughout this application. Any embodiment discussed with respect to one aspect of the invention applies to other aspects of the invention as well and vice versa. Each embodiment described herein is understood to be embodiments of the invention that are applicable to other aspects of the invention. It is contemplated that any embodiment or aspect discussed herein can be combined with other embodiments or aspects discussed herein and / or implemented with respect to any method or composition of the invention, and vice versa. Furthermore, compositions of the invention can be used to achieve methods of the invention.

[0019] The following includes definitions of various terms and phrases used throughout this specification.

[0020] The terms “about” or “approximately” are defined as being close to as understood by one of ordinary skill in the art. In one non-limiting embodiment, the terms are defined to be within 10%, preferably within 5%, more preferably within 1%, and most preferably within 0.5%.

[0021] The terms “wt.%”, “vol.%”, or “mol.%” refers to a weight percentage of a component, a volume percentage of a component, or molar percentage of a component, respectively, based on23T&I0046-WO-ORD 11the total weight, the total volume of material, or total moles, that includes the component. In a nonlimiting example, 10 grams of component in 100 grams of the material is 10 wt.% of component.

[0022] The term “substantially” and its variations are defined to include ranges within 10%, within 5%, within 1%, or within 0.5%.

[0023] The terms “inhibiting” or “reducing” or “preventing” or “avoiding” or any variation of these terms, when used in the claims and / or the specification includes any measurable decrease or complete inhibition to achieve a desired result.

[0024] The term “effective,” as that term is used in the specification and / or claims, means adequate to accomplish a desired, expected, or intended result.

[0025] The use of the words “a” or “an” when used in conjunction with any of the terms “comprising,” “including,” “containing,” or “having” in the claims, or the specification, may mean “one,” but it is also consistent with the meaning of “one or more,” “at least one,” and “one or more than one.”

[0026] The words “comprising” (and any form of comprising, such as “comprise” and “comprises”), “having” (and any form of having, such as “have” and “has”), “including” (and any form of including, such as “includes” and “include”) or “containing” (and any form of containing, such as “contains” and “contain”) are inclusive or open-ended and do not exclude additional, unrecited elements or method steps.

[0027] The methods of the present invention can “comprise,” “consist essentially of,” or “consist of’ particular ingredients, components, compositions, etc. disclosed throughout the specification. With respect to the transitional phrase “consisting essentially of,” in one nonlimiting aspect, a basic and novel characteristic of the methods of the present invention are their abilities to remove contaminants from mixed plastic waste.

[0028] Other objects, features and advantages of the present invention will become apparent from the following figures, detailed description, and examples. It should be understood, however, that the figures, detailed description, and examples, while indicating specific embodiments of the invention, are given by way of illustration only and are not meant to be limiting. Additionally, it23T&I0046-WO-ORD 12is contemplated that changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description. In further embodiments, features from specific embodiments may be combined with features from other embodiments. For example, features from one embodiment may be combined with features from any of the other embodiments. In further embodiments, additional features may be added to the specific embodiments described herein.BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Advantages of the present invention may become apparent to those skilled in the art with the benefit of the following detailed description and upon reference to the accompanying drawings.

[0030] FIG. 1 shows a non-limiting example schematic of a contaminant removal system using the methods of the present invention. The system includes a reactor capable of receiving a mixed plastic waste and a solvent and capable of mixing and heating the mixed plastic waste and solvent. The system produces a waste solvent and / or contaminants enriched stream and a partially depolymerized oligomers product stream.

[0031] FIG. 2 shows a non-limiting example schematic of a contaminant removal system using the methods of the present invention. The system includes a reactor capable of receiving a mixed plastic waste and a solvent and capable of mixing and heating the mixed plastic waste and solvent to form a reaction product mixture. The reaction product mixture can be removed from the reactor and moved to a separation unit. A waste solvent and / or contaminants enriched stream and a partially depolymerized oligomers stream can be produced by the separation unit.

[0032] FIG. 3 shows a non-limiting example schematic of a contaminant removal system using the methods of the present invention. The system includes a reactor capable of receiving a mixed plastic waste and a solvent and capable of mixing and heating the mixed plastic waste and solvent to form a reaction product mixture. The reaction product mixture can be removed from the reactor and moved to a cooling unit to form a precipitate stream. The precipitate stream can be moved to a separation unit. A waste solvent and / or contaminants enriched stream and a partially depolymerized oligomers stream can be produced by the separation unit.23T&I0046-WO-ORD 13

[0033] FIG. 4 shows a non-limiting example schematic of a contaminant removal system using the methods of the present invention. The system includes a melting unit capable of receiving a solid mixed plastic waste. The melting unit can melt the plastic waste to form a mixed plastic waste that is a melt. The mixed plastic waste that is a melt can enter a reactor capable of receiving a mixed plastic waste and a solvent and capable of mixing and heating the mixed plastic waste and solvent. The system produces a waste solvent and / or contaminants enriched stream and a partially depolymerized oligomers stream.

[0034] While the invention is susceptible to various modifications and alternative forms, specific embodiments thereof are shown by way of example in the drawings. The drawings may not be to scale.DETAILED DESCRIPTION OF THE INVENTION

[0035] A solution to at least one of the problems associated with contaminant removal from mixed plastic waste has been discovered. The carbon recovery from mixed plastic waste can be enhanced by partially breaking down the polymers to lower molecular weight oligomers instead of hydrocarbon liquids, thereby minimizing the overall gas yield. These oligomers in solid powder form at room temperature are relatively easy to handle and can be fed directly to certain petrochemical operations. The solution herein produces decontaminated oligomers (such as removing chlorine, metals and, other inorganic components in the mixed plastic waste), that increases the value of the product and can reduce or avoid having to blend the product with other plastics (e.g., virgin plastics) so that the product is suitable for downstream processes. The process can decontaminate these mixed plastic waste without or with minimal reduction or controlled reduction of the molecular weight of the plastics in the mixed plastic waste and can do so with efficient heat and mass transfer.

[0036] These and other non-limiting aspects of the present invention are discussed in further detail in the following sections.

[0037] Referring to FIG. 1, system 100 includes reactor 102. Mixed plastic waste (MPW) stream 106 and solvent 116 can enter reactor 102 to form a reactor mixture. MPW stream 106 can include one or more polymers. Polymers can include polyethylene terephthalate (PET), low-density and high-density polyethylene (PE), polypropylene (PP), polystyrene (PS), polyvinyl23T&I0046-WO-ORD 14chloride (PVC), poly vinylidene chloride (PVDC), chlorinated polyethylene (CPE), chlorosulphonated polyethylene (CSM), or chloroendic acid polyester, or any combination or blend thereof. In a preferred aspect, one or more of the polymers contain chlorine, such as PVC. Other miscellaneous plastics can be present in the MPW stream such as acrylonitrile butadiene styrene found in electronic waste, polyurethane foam packaging, carpet nylon, and / or polysulfone. MPW stream 106 can also include impurities. Non-limiting examples of impurities include paper, wood, aluminum foil, some metallic conductive fillers, and / or halogenated or non-halogenated flame retardants. MPW stream can be in a solid form or in a flowable form (e.g., a viscous low-flowing material and / or a liquid). The solvent 116 may include a polar solvent. The solvent 116 may include additional components such as dissolved or solid salts, dispersing agents such as surfactants to help with dispersion of polymers in the solvent, acids, bases such as NaOH, buffers, metal oxides, metal hydroxides, hydroxides, and / or catalysts. In some aspect, one or more additional component of the solvent is added to the solvent 116 before the solvent contacts the mixed plastic waste. In some aspects, one or more additional component is present in the mixed plastic waste 106 before contacting the solvent 116 and moves into the solvent 116 during the reaction. In some aspects, the solvent 116 is water and / or an alkane hydrocarbon, such as straightchain alkane hydrocarbons. In some aspects the solvent 116 is water. In some aspects, the solvent 116 is hexadecane. In some instances, the nonpolar solvent 116 is an organic solvent. In some aspects, the solvent 116 is a polar organic solvent. In some aspects, the solvent 116 is an inorganic polar solvent. In some aspects, the solvent 116 has a pH of greater than 7.5. In some aspects, one or more of the solvents in the solvent 116 is miscible with at least a portion of the plastic in the plastic waste stream 106. In some aspects, the miscible solvent is a non-polar organic solvent. In some aspects, the solvent 116 and the MPW stream 106 will form two phases when combined. In some aspects, the mixed plastic waste will be in one phase and the solvent in another.

[0038] Reactor 102 can have a mixing capability. Reactor 102 can be a unit capable of heating and mixing the MPW stream 106 and solvent 116. Non-limiting examples of reactors can include a rotor-stator mixer, a stirred tank reactor, an agitated vessel, a vessel with ultrasonics, a rotating reactor, etc. In reactor 102, MPW stream 106 can be heated under agitation sufficient to disperse polymeric material in the phase of the MPW stream 106 into the phase of the solvent 116. In some aspects, the reactor 102 can be heated under agitation sufficient to release contaminants, such as heteroatoms such as chlorine (such as in the form of HC1) from the MPW stream. In some aspects,23T&I0046-WO-ORD 15the reactor 102 is capable of causing mixing. In some aspects, the reactor 102 is capable of causing high shear mixing. In some aspects, the rector may include a mixer such as a pitched blade turbine (PBT), helical ribbon impeller, combination of PBT and helical ribbon impeller, hydrofoil impeller, rushton turbine, sawtooth disc impeller, rotor-stator, static mixer, agitated vessel, colloid mill, liquid whistle, valve homogenizer, ultrasonication, agitator, closed rotor, sawtooth blade, microfluidics, or a combination thereof. In some aspects, the mixer can be fixed to the reactor. In some aspects, the mixer may be removable from the reactor. In some aspects, the reactor comprises a reactor that moves to mix the reactor mixture. The reaction may occur under mixing to produce particles with a mean average diameter of 500 micrometers or less, 400 micrometers or less, 300 micrometers or less, 200 micrometers or less, 150 micrometers or less, 100 micrometers or less, 75 micrometers or less, or 50 micrometers or less. The reactor may agitate and / or mix the MPW stream 106 and the solvent 116 at temperature below the critical point of the solvent at the pressure in the reactor 102. In some aspects, the temperature is at or below 380 °C. In some aspects, the temperature is at or above 250 °C, such as 250 to 380 °C, or any range or value therebetween. In some aspects, the pressure in the reactor is greater than atmospheric pressure. In some aspects, the pressure in the reactor 102 is at or above 50 bar. In some aspects, the pressure in the reactor 102 is at or below 200 bar, such as 50 to 200 bar, or any range or value therebetween.

[0039] In reactor 102, MPW stream 106 can be heated under agitation sufficient to cause hydrogenation of polymeric material with or without the presence of a catalyst. Such hydrogenation may minimize the reaction of olefins with HC1 that may be released during decomposition of chlorinated polymers, this may reduce the production of organic chlorides in the product oligomers. In some aspects, the reaction conditions do not cause hydrogenation of the polymeric material and / or the partially depolymerized oligomer products. Reactor 102 can be a batch reactor or a reactor capable of a continuous reaction with or without continuous feeds and / or product production.

[0040] A residence time of MPW stream 106 and solvent stream 116 in reactor 102 depends on the temperature and if the reaction products are cooled in the reactor 102. Lower residence time can be used when operating at higher temperatures. For example, at 300 °C, the residence time of 1 minute or lower may be sufficient for the reaction to occur, whereas at 250 °C a residence time of at least 10 minutes may be required. In general, the residence time can be 30 minutes or less, 2523T&I0046-WO-ORD 16minutes or less, 20 minutes or less, 15 minutes or less, 10 minutes or less, or 5 minutes or less, or 0.1 minute to 30 minutes, or any value or range there between. The short residence time in reactor 102 provides the advantage of limiting side reactions from HC1, that may be formed during the reaction, reacting with the MPW stream 106 to produce additional inorganic chlorides and organic halides. In other aspects, the residence time can be greater than 30 minutes (e.g., 35, 40, 45, 50, 55, 60, 70, 80, 90, 100, 110, 120 minutes, or more).

[0041] Reactor 102 may be a unit capable of separating the reaction products into a partially depolymerized oligomer stream 122 and a waste solvent and / or contaminants stream 120. In some aspects, after the reaction, the products in the reactor 102 can be cooled with or without agitation to facilitate separation of the partially depolymerized oligomer stream 122 and the waste solvent and / or contaminants stream 120. The partially depolymerized oligomer may form a solid during the cooling while the solvent remains a liquid. The solid partially depolymerized oligomer may be separated into the partially depolymerized oligomer stream 122 and the liquid solvent may be separated into the waste solvent and / or contaminants stream 120. The reactor 102 may separate the partially depolymerized oligomer stream 122 and the waste solvent and / or contaminants stream 120 by phase separation, screening, centrifugal movement, filtration, density, polarity, etc. The partially depolymerized oligomer stream 122 may contain partially depolymerized oligomer in the form of particles. The particles may be microparticles and / or nanoparticles. In some aspects, the particles have a mean diameter of less than 10 micrometers. In some aspects, the particles have a mean diameter of greater than 1 nm, such as 1 nm to 10 micrometers or any number between or range therein. In some aspects, the partially depolymerized oligomers have an average MW of less than 20,000 g / mol. In some aspects, the particles have an average MW of greater than 100 g / mole, such as 100 to 20,000 g / mol, or number between or any range thereof. The partially depolymerized oligomer stream 122 and / or the waste solvent and / or contaminants stream 120 can exit the reactor 102 and be further processed, stored, transported, or the like. In some aspects, the partially depolymerized oligomer stream 122 is dried to form a powdered partially depolymerized oligomer.

[0042] Referring to FIGs. 2, 3 and 4, variations of the systems are shown. The reference numbers from FIG. 1 are used and refer to the same streams and units unless otherwise indicated. Referring to FIG. 2, system 200 illustrates reactor 102 and a separation unit 104. As explained referring to FIG. 1, the reactor 102 may produce a partially depolymerized oligomer and a solvent23T&I0046-WO-ORD 17containing contaminants from the MPW stream 106. The product is a reaction product mixture 108 that may contain both the partially depolymerized oligomer(s) and the solvent(s) containing contaminate(s). The reaction product mixture 108 may be removed from the reactor 102 in a continuous or a batch process and fed to the separation unit 104. The separation unit 104 may separate the partially depolymerized oligomer(s), and solvent(s) containing contaminate(s), and / or contaminants from all of the others or from one of the others. In FIG. 2, the separation unit 104 separates the reaction product mixture 108 into a partially depolymerized oligomer stream 122 and a waste solvent and / or contaminants stream 120. The separation unit 104 may cool the reaction product mixture 108 with or without agitation to facilitate separation of the partially depolymerized oligomer stream 122 and the waste solvent and / or contaminants stream 120. The partially depolymerized oligomer may form a solid during the cooling while the solvent remains a liquid. The solid partially depolymerized oligomer may be separated into the partially depolymerized oligomer stream 122 and the liquid solvent may be separated into the waste solvent and / or contaminants stream 120. The separation unit 104 may separate the partially depolymerized oligomer stream 122 and the waste solvent and / or contaminants stream 120 by phase separation, cyclone separation, screening, centrifugal movement, filtration, density, polarity, etc. The partially depolymerized oligomer stream 122 and / or the waste solvent and / or contaminants stream 120 can exit the separation unit 104 and be further processed, stored, transported, or the like.

[0043] Referring to FIG. 3, system 300 illustrates reactor 102, separation unit 104, and a cooling unit 112. As explained referring to FIG. 1, the reactor 102 may produce a partially depolymerized oligomer and a solvent containing contaminants from the MPW stream 106. The product is a reaction product mixture 108 that may contain both the partially depolymerized oligomer(s) and solvent(s) containing contaminate(s). The reaction product mixture 108 may be removed from the reactor 102 in a continuous or a batch process and fed to the cooling unit 112. The cooling unit 112 may cool the reaction product mixture 108 with or without agitation to facilitate the solidification of the partially depolymerized oligomer and form a precipitate stream 110. The cooling unit 112 may use air cooling or facilitated cooling such as use of a cool or cold water / liquid jacket, a compressor and cooling fluid, or use of chilled gas, etc. to cool the reaction product mixture 108. The precipitate stream 110 may be removed from the cooling unit 112 in a continuous or a batch process and fed to the separation unit 104. As explained referring to FIG. 2, the separation unit may separate the partially depolymerized oligomer(s), and solvent(s) containing23T&I0046-WO-ORD 18contaminant(s), and / or contaminants from all of the others or from one of the others. The separation unit 104 separates the precipitate stream 110 into a partially depolymerized oligomer stream 122 and a waste solvent and / or contaminants stream 120. The separation unit 104 may further cool the reaction product mixture 108 with or without agitation to facilitate separation of the partially depolymerized oligomer stream 122 and the waste solvent and / or contaminants stream 120. The partially depolymerized oligomer may form a solid during the cooling while the solvent remains a liquid. The solid partially depolymerized oligomer may be separated into the partially depolymerized oligomer stream 122 and the liquid solvent may be separated into the waste solvent and / or contaminants stream 120. The separation unit 104 may separate the partially depolymerized oligomer stream 122 and the waste solvent and / or contaminants stream 120 by phase separation, cyclone separation, screening, centrifugal movement, filtration, density, polarity, etc. The partially depolymerized oligomer stream 122 and / or the waste solvent and / or contaminants stream 120 can exit the separation unit 104 and be further processed, stored, transported, or the like.

[0044] Referring to FIG. 4, system 400 illustrates reactor 102 and melting unit 118. As explained referring to FIG. 1, the reactor 102 may produce a partially depolymerized oligomer and a solvent containing contaminants from the MPW stream 106. The product may contain both the partially depolymerized oligomer(s) and solvent(s) containing contaminate(s). The product may be separated as explained referring to FIG. 1, or as explained referring to FIG. 2 (not shown in FIG. 4), or as explained referring to FIG. 3 (not shown in FIG. 4). The partially depolymerized oligomer stream 122 and / or the waste solvent and / or contaminants stream 120 can be further processed, stored, transported, or the like. The MPW stream 106 may be a melted mixed plastic waste stream obtained by melting a solid mixed plastic waste (MPW) stream 114 in a melting unit 118. Melting unit 118 can be any unit capable of melting solid mixed plastic waste 114. Nonlimiting examples of a melting unit can include a heated jacket container, an extruder, a kneader, a gas burner, a heat exchange unit that includes a static mixer, or a batch reactor. Non-limiting examples of extruders can include a single, or twin screw or an Auger reactor with flight geometries of either ribbon, paddles, other constructs, interrupted, or shaftless. In melting unit 118, solid MPW stream 114 can be heated under agitation to a temperature sufficient to melt the solid MPW stream. Melting temperatures can be up to 350 °C, or 200 °C to 325 °C, or 200 °C, 225 °C, 250 °C, 275 °C, 300 °C, 325 °C, 350 °C, or any range or value there between. A residence time of melting solid MPW stream in melting unit 118 may depend on the temperature and / or pressure.23T&I0046-WO-ORD 19Lower residence time can be used when operating at higher temperatures. For example, at 300 °C, the residence time of 1 minute or lower may be sufficient, whereas at 250 °C a residence time of at least 10 minutes may be required. In general, the residence time can be 30 minutes or less, 25 minutes or less, 20 minutes or less, 15 minutes or less, 10 minutes or less, or 5 minutes or less, or 0.1 minute to 30 minutes, any value or range there between. The short residence time in melting unit 118 provides the advantage of limiting side reactions from HC1, that may be formed during the melting process, reacting with the melting MPW stream to produce additional inorganic chlorides and organic halides. In other aspects, the residence time can be greater than 30 minutes (e.g., 35, 40, 45, 50, 55, 60, 70, 80, 90, 100, 110, 120 minutes, or more).

[0045] Systems 100-400 can include one or more reactors, heating and / or cooling devices (e.g., insulation, electrical heaters, jacketed heat exchangers in the wall), separators, melting units, or controllers (e.g., computers, flow valves, automated valves, etc.) that can be used to control temperatures, pressures, and material flow of the units. While only one unit is shown, it should be understood that multiple units (e.g., multiple reaction units or multiple separation units) can be used.EXAMPLESExample 1

[0046] Experiments were conducted with commercially available mixed plastic waste streams sourced from Germany, DKR323.

[0047] 15 g of DKR323 (containing 12,000 ppm of Cl), 15 g of hexadecane, and 40 g of deionized (DI) water was added to a 100 ml parr reactor, sealed with no effluent escaping the reactor and heated to 270 °C for 120 min. The reactor was then allowed to cool down to room temperature, before collecting the polymer and liquid samples for analysis on X-ray Fluorescence (XRF). The XRF analysis showed that all the hexadecane was consumed by the DKR323 forming a swollen polymer while the aqueous water layer showed -3,800 ppm of Cl accounting for nearly 84% of Cl in the feed DKR323. This showed that Cl, which is released as HC1 during chlorinated polymer decomposition at -270 °C, readily moved to the aqueous solvent. Some metals were also detected in the aqueous phase.23T&I0046-WO-ORD 20Example 2

[0048] Experiments were conducted with commercially available mixed plastic waste streams sourced from Germany, DKR323.

[0049] 15 g of DKR323 (containing 12,000 ppm of Cl) and 40 g of 0. IN NaOH was added to a 100 ml parr reactor, sealed with no effluent escaping the reactor and heated to 270 °C for 120 min. Polyolefins were not expected to undergo any cracking at this low temperature while chlorinated polymers (e.g., PVC) were expected to decompose and release HC1. The reactor was then allowed to cool down to room temperature, before collecting the polymer and liquid samples for analysis on XRF. The XRF analysis showed that the aqueous water layer showed -3,500 ppm of Cl accounting for nearly 78% of Cl in the feed DKR323. This showed that Cl, which is released as HC1 during chlorinated polymer decomposition at -270 °C, readily moved to the NaOH solvent.

[0050] Together, the results from Example 1 and Example 2 demonstrate that Cl released as HC1 during the decomposition of chlorinated polymers readily dissolves in H2O / O.IN NaOH suggesting that hydrothermal treatment of waste plastic streams at low temperatures facilitates decomposition of chlorinated polymers releasing HC1 which will readily dissolve in a polar solvent.

[0051] It should be noted that the reactor used in Example 1 and Example 2 does not facilitate perfect mixing conditions but still showed 78-84% drop in Cl content in the mixed plastic waste product, with the Cl moving from DKR323 to the aqueous phase.Example 3

[0052] Some metals were detected in the aqueous phase of the reaction products of Example 1 and Example 2. Samples of the aqueous phase were filtered through a 0.45 micron filter before analysis on XRF. The detection of the metals suggested the metals measured in this analysis were likely dissolved in the aqueous phase. Results of the metal detection is found in Table 1. These results suggest that metals (e.g., Ca, Si, and K) move to the aqueous phase from DKR323. Fe and Ni was not seen with the 0. IN NaOH run but was seen in the hexadecane and water run. Not to be bound by theory, the Fe and Ni may have been products of corrosion of the reactor head by the acidic medium (HCI+H2O) produced in the hexadecane and water run. That may also explain why23T&I0046-WO-ORD 21Fe and Ni were not seen with the 0. IN NaOH run, as HC1 may be converted to NaCl in this case reducing the acidity in the reactor and mitigating corrosion.

[0053] Some solids were also detected settled at the bottom of the aqueous phase before filtration. The solids suggested a high density of some component(s) from the mixed plastic waste entered the solvent during the reaction.Table 1 (ND = not detected)

[0054] Although embodiments of the present application and their advantages have been described in detail, it should be understood that various changes, substitutions, and alterations can be made herein without departing from the spirit and scope of the embodiments as defined by the appended claims. Moreover, the scope of the present application is not intended to be limited to the particular embodiments of the process, machine, manufacture, composition of matter, means, methods and steps described in the specification. As one of ordinary skill in the art will readily appreciate from the above disclosure, processes, machines, manufacture, compositions of matter, means, methods, or steps, presently existing or later to be developed that perform substantially the same function or achieve substantially the same result as the corresponding embodiments described herein can be utilized. Accordingly, the appended claims are intended to include within their scope such processes, machines, manufacture, compositions of matter, means, methods, or steps.

Claims

23T&I0046-WO-ORD 22CLAIMS1. A method of removing contaminants from a plastic waste stream, the method comprising:(a) providing the plastic waste stream and a solvent to a reactor having a mixing capability, wherein the plastic waste stream and the solvent form a reactor mixture having a first phase and a second phase, and wherein the first phase of the reactor mixture comprises the plastic waste stream and the second phase of the reactor mixture comprises the solvent;(b) subjecting the reactor mixture to reactor conditions comprising a temperature that is less than a threshold temperature and a pressure that is greater than a threshold pressure such that the solvent remains in the second phase in order to disperse polymeric material of the first phase into the second phase under mixing conditions to produce a reaction product mixture comprising partially depolymerized oligomer products from the polymeric material in the first phase and at least a portion of one or more contaminants associated with the plastic waste stream in the second phase; and(c) performing one or more operations to recover the partially depolymerized oligomer products from the reaction product mixture.

2. The method of claim 1, wherein the one or more operations to recover the partially depolymerized oligomer products from the reaction product mixture include: cooling the reaction product mixture under mixing conditions such that the oligomer products solidify; andseparating the solidified oligomer products from the reaction product mixture.

3. The method of any one of claims 1 to 2, wherein the one or more operations to recover the partially depolymerized oligomer products from the reaction product mixture include: withdrawing the reaction product mixture from the reactor;cooling the reaction product mixture in a heat exchanger such that the oligomer products solidify, preferably with mixing; and23T&I0046-WO-ORD 23separating the solidified oligomer products from the reaction product mixture.

4. The method of any of claims 2 or 3, wherein the solidified oligomer products are separated from the reaction product mixture via filtration.

5. The method of any of claims 2 or 3, wherein the solidified oligomer products are separated from the reaction product mixture via a cyclone separator.

6. The method of any one of claims 1 to 5, wherein the threshold temperature is at least 200 °C, preferably 250 °C to 380 °C, and wherein the threshold pressure is at least 50 bar, preferably 50 bar to 200 bar, to effect depolymerization of polymers in the plastic waste stream to produce the oligomer products.

7. The method of any one of claims 1 to 6, wherein:the reaction product mixture in step (a) comprises the plastic waste stream dispersed in the solvent as particles having an average particle size of 500 micrometers or less; and / orthe partially depolymerized oligomer products in step (c) are at least partially located in the second phase and the partially depolymerized oligomer products in the second phase comprise particles having an average particle size of less than 10 mm.

8. The method of any one of claims 1 to 7, wherein the solvent includes a dispersing agent.

9. The method of claim 8, wherein the dispersing agent is a surfactant.

10. The method of any one of claims 1 to 9, wherein the plastic waste stream is a solid plastic waste stream.

11. The method of any one of claims 1 to 9, wherein the plastic waste stream is a molten plastic waste stream and / or a stream of plastic waste stream dissolved in an organic solvent.

12. The method of claim 11, wherein the reactor is configured to mitigate agglomeration of the molten plastic waste stream and to suspend the polymeric material as particles in the solvent.23T&I0046-WO-ORD 2413. The method of any one of claims 1 to 12, wherein:(i) depolymerization of chlorinated polymers in the plastic waste stream results in release of HC1, which is trapped by a metal oxide / hydroxide in the solvent thereby resulting in lower chlorine content in the oligomer products; and / or(ii) contaminants in the plastic waste stream comprise one or more halogens, one or more metals, and / or one or more heteroatoms, preferably the contaminants comprise chlorine (Cl), oxygen (O), nitrogen (N), metals, or a combination thereof.

14. The method of claim 1, wherein the solvent is a polar solvent.

15. The method of claim 14, wherein the solvent comprises a mixture of solvents, the mixture of solvents comprising the polar solvent and a non-polar organic solvent that is miscible with at least a portion of plastic in the plastic waste stream.

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