Method for thermally cracking plastic waste

Abstract

Systems and methods are provided for recycling plastic waste in a cracker, in one embodiment comprising at least thermally cracking a plastic waste feed and cracking a feedstock to produce at least a cracking product comprising hydrocarbons wherein the cracking feedstock has a T10 distillation point of 343 DEG C or higher; measuring the concentration of pollutants; and adjusting the plastic waste feed in response to the contaminant concentration.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims the benefit of and priority to U.S. Provisional Application No. 63 / 403,415, filed on September 2, 2022, the disclosure of which is incorporated herein by reference. Technical Field

[0003] Systems and methods for recycling plastic waste in a cracker are provided. Background Art

[0004] The processing of plastic waste is an increasingly important topic. It would be desirable to have a processing path that allows plastic waste to be converted into liquid products. The liquid products can potentially be used as fuels, lubricants and / or as raw materials for the production of olefin monomers. Although dedicated processing systems can be used for plastic waste conversion, such dedicated systems require a large amount of initial capital costs and a constant supply of waste plastic feed. Therefore, it would be desirable to make full use of existing processing equipment to be able to process plastic waste together.

[0005] Another difficulty in converting plastic waste is that the properties of the plastic waste can vary widely. Therefore, it would be desirable to have a processing system and method that can tolerate variability in the plastic waste feed. Summary of the invention

[0006] Disclosed herein is an example method for processing plastic waste, comprising: thermally cracking at least a plastic waste feed and a cracking feedstock to produce at least a cracking product comprising hydrocarbons, wherein the cracking feedstock has a T10 distillation point of 343°C or greater; measuring a contaminant concentration; and adjusting the plastic waste feedstock in response to the contaminant concentration.

[0007] Also disclosed herein is an example method for processing plastic waste, comprising: physically processing a plastic waste feed to reduce the maximum particle size of the plastic waste feed; combining the plastic waste feed with a carrier fluid to form a combined feedstock; physically processing the combined feedstock to reduce the maximum particle size of solid particles in the combined feedstock; preheating the combined feedstock to cause melting of the solid particles in the combined feedstock; and thermally cracking the combined feedstock to produce at least a cracking product comprising hydrocarbons.

[0008] Also disclosed herein is an example method for processing plastic waste, comprising: identifying target specifications required for a plastic waste feed; determining a mixture of at least two plastic waste compositions that meets the target specifications; mixing at least two plastic waste compositions to form a plastic waste feed; and thermally cracking at least the plastic waste feed and a cracking feed to produce at least a cracking product comprising hydrocarbons, wherein the cracking feed has a T10 distillation point of 343°C or higher.

[0009] These and other features and properties of the methods and systems disclosed in the present disclosure and their advantageous applications and / or uses will be apparent from the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] To assist persons of ordinary skill in the relevant art in making and using the subject matter herein, reference is made to the accompanying drawings, wherein:

[0011] Figure 1 is an illustrative description of a method of pre-processing plastic waste according to an embodiment of the present disclosure.

[0012] Figure 2 is an illustrative description of a method of feeding plastic waste to a pyrolysis reactor using a feed system according to some embodiments of the present disclosure.

[0013] Figure 3 is an illustrative description of a fluidized bed coking system including a coker, a heater, and a gasifier according to some embodiments of the present disclosure.

[0014] Figure 4 is an illustrative description of a fluidized bed coking system including a coker and a gasifier according to some embodiments of the present disclosure.

[0015] Figure 5 is an illustrative description of a delayed coking system including a coker and a fractionator according to some embodiments of the present disclosure. DETAILED DESCRIPTION

[0016] In various embodiments, systems and methods for chemical recycling of artificial turf are provided. In some embodiments, the method for chemical recycling of artificial turf includes pyrolyzing a plastic waste feed to produce hydrocarbons. In some embodiments, the plastic waste feed is co-processed with a conventional cracking feedstock (e.g., petroleum vacuum residue) in a pyrolysis environment. Although the systems and methods disclosed herein are suitable for pyrolyzing plastic waste feeds in a variety of different cracking environments, they may be particularly suitable for pyrolyzing plastic waste feeds in a coking environment (e.g., delayed coking and fluidized coking environments).

[0017] Cracking feed

[0018] According to this embodiment, the plastic waste feed is cracked to produce hydrocarbons.In some embodiments, the plastic waste feed is co-processed with additional cracking feedstock.

[0019] The plastic waste feed includes one or more different types of plastic waste compositions. As used herein, the term "plastic waste" refers to a waste material that includes plastics in an amount of at least 50% by weight and can include plastics in an amount of at least 80% by weight, at least 90% by weight or more. A plastic waste composition is a composition that includes one or more types of plastic waste. The plastic waste composition can include any of a variety of plastics, including thermosetting and thermoplastic polymers. Examples of suitable plastics include polymers such as polyethylene terephthalate (PET or PETE), high-density polyethylene (HDPE), low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE), polypropylene (PP), polystyrene (PS) and combinations thereof. In some embodiments, the plastic waste composition includes plastics obtained from any source, including but not limited to municipal, industrial, commercial or consumer sources. In some embodiments, the plastic waste composition includes post-consumer use plastics. Additional examples of suitable plastic waste compositions include plastics obtained from common sources or from mixed sources, including mixed plastic wastes obtained from municipal or regional sources and / or from waste streams of polyethylene terephthalate (PET), high density polyethylene (HDPE), low density polyethylene (LDPE), linear low density polyethylene (LLDPE), polypropylene (PP) and / or polystyrene (PS). Further, examples of suitable plastic waste compositions include any of a variety of used polymeric articles, without limitation. Some examples of many types of polymeric articles include: films (including cast, blown and other forms), sheets, fibers, woven and nonwoven fabrics, furniture (e.g., garden furniture), artificial turf, sporting equipment, bottles, food and / or liquid storage containers, transparent and translucent articles, toys, pipes and tubes, sheets, packaging, bags, sacks, coatings, caps, closures, crates, pallets, cups, non-food containers, barrels, insulation and medical devices. Additional examples include automotive, aerospace, marine and / or water transportation copolymer parts (e.g., bumpers, grilles, trim, fenders, instrument panels, etc.), wire and cable jacketing, agricultural films, geomembranes, playground equipment, and other such articles, whether blow molded, rotomolded, injection molded, etc. One of ordinary skill will appreciate that such polymer articles can be made from any of a variety of polymeric and / or non-polymeric materials, and that the polymeric materials can vary widely (e.g., ethylene-based, propylene-based, butyl-based polymers, and / or any C2-C6-based 40 or even higher olefins, and further comprising monomers based on any one or more types such as C2-C 40Common examples include ethylene, propylene, butene, pentene, hexene, heptene, octene and styrene; and polyolefinic (including cycloolefin) monomers such as ethylidene norbornene (ENB) and vinylidene norbornene (VNB) (including, for example, when such cycloolefins are used as comonomers, such as with ethylene monomers).

[0020] In some embodiments, the plastic waste composition includes one or more plastics classified by the Plastics Industry Association as Plastic Identification Codes (PIC) 1 to 7. For example, examples of suitable plastics include one or more of the following plastics: polyethylene terephthalate classified as PIC 1; high-density polyethylene classified as PIC 2; polyvinyl chloride classified as PIC 3; low-density polyethylene classified as PIC 4; polypropylene classified as PIC 5; polystyrene classified as PIC 6; and polycarbonate and other plastics classified as PIC 7. Combinations of plastics classified as PIC 1 to PIC 7 are also suitable according to this embodiment.

[0021] In addition to the polymer, the plastic waste composition may also include various other components. Such other components may include additives, modifiers, packaging dyes and / or other components that are typically added to the polymer during and / or after formulation. The plastic waste composition may also include any components typically found in plastic waste (e.g., paper). Finally, the plastic waste composition may also be mixed with a carrier fluid so that the feedstock for the thermal cracking process corresponds to a solution or slurry of the plastic waste composition.

[0022] In embodiments where the plastic waste feed is at least partially introduced as a solid into a thermal cracking environment, having a small particle size can facilitate the transportation of solids and / or reduce the possibility of incomplete conversion. In some embodiments, the waste feedstock includes polymer wastes having a maximum particle size of 0.01 millimeter ("mm") to 75mm, 0.01mm to 50mm, 0.01 to 25mm, 0.01 to 10mm, 1mm to 50mm, 1mm to 25mm, 1mm to 10mm, 5mm, or 0.1mm to 5mm, or 0.01mm to 3mm, or 0.1mm to 3mm, or 0.01mm to 3mm, or 0.1mm to 3mm, or 1mm to 5mm, or 1mm to 3mm. For determining the maximum particle size, the particle size is defined as the diameter of the smallest surrounding sphere containing the particle. Additionally or alternatively, the plastic waste in the plastic waste feed can be melted and / or granulated to improve the uniformity of the plastic particle size. In some aspects, the plastic waste has a maximum particle size of 75 mm or less, 50 mm or less, 25 mm or less, 10 mm or less, or 5.0 mm or less. Additionally or alternatively, the bulk density of the plastic waste can be selected, for example, to facilitate transportation. In some embodiments, the bulk density can be adjusted, for example, by other techniques such as compaction or granulation. In some embodiments, the plastic waste has a bulk density of 10 lb / ft 3 Up to 35lb / ft 3 (160kg / m 3 Up to 560kg / m 3 ), or 20lb / ft 3 Up to 35lb / ft 3 (320kg / m 3 Up to 560kg / m 3 ), or 25lb / ft 3 Up to 35lb / ft 3 (400kg / m 3 Up to 560kg / m 3 )’s bulk density.

[0023] In some embodiments, the plastic waste feed meets the target specifications of the thermal cracking environment. The target specifications may include physical properties, chemical properties, or both. Example physical properties of the specifications may include particle size. Example chemical properties of the specifications may include pollutant concentrations. The pollutant limits of a thermal cracking unit (such as a coker unit) may be set by several design and operating factors, and specific limits are determined by the specific unit and refinery configuration. For example, the specifications may include the upper limit of the concentration of one or more pollutants such as total halides (such as chlorides, fluorides, bromides) in the plastic waste. In some embodiments, the specifications may include 0.5 wt %, 0.1 wt %, or a smaller upper limit of total halides in the plastic waste feed. These limits will be extensively set for the coker by furnace and reactor metallurgy, fractionator and fractionator top metallurgy, fractionator top operating temperature, and these limits may be further affected by corrosion risks from other factors. The fouling risk of the device may also be set to limit the pollutant concentration with a specific fouling risk in furnace tubes, feed preheating exchangers, fractionator trays, and product heat exchangers. The specific configuration of the process route of the coker product stream to the downstream devices can result in additional contaminant limits set by these downstream processes. Downstream processes can be limited by corrosion or catalyst deactivation issues. Coker plastic feed compositions can also be limited by coker unit yield and quality issues. The unit can be expected to limit the additional generation of aromatic compounds such as benzene or olefinic products or overall unit coke production.

[0024] Optionally, a carrier fluid may also be included in the plastic waste feed to help introduce the plastic waste into the thermal cracking environment. For introduction into the thermal cracking environment, it may be convenient for the raw material to be in the form of a slurry. If the carrier fluid is used to transport the plastic waste feed, any suitable fluid may be used. Examples of suitable carrier fluids may include, but are not limited to, a wide range of petroleum or petrochemical products. For example, some suitable carrier fluids include crude oil, naphtha, kerosene, diesel, light or heavy cycle oil, catalytic slurry oil, and gas oil. Other potential carrier fluids may correspond to cycloalkanes and / or aromatic solvents, such as toluene, benzene, methylnaphthalene, cyclohexane, methylcyclohexane, and mineral oil. Still other carrier fluids may correspond to refined fractions such as gas oil fractions or naphtha fractions from a coker. As another example, a distillate and / or a fraction of a gas oil boiling range produced by thermal cracking of the plastic waste feed (either alone or with additional raw materials) may be used.

[0025] In various embodiments, thermal cracking can be used to process a combination of raw materials corresponding to a mixture of conventional cracking raw materials and plastic waste feedstocks. In some embodiments, conventional cracking raw materials are used as carrier fluids for plastic waste feedstocks. Conventional cracking raw materials may correspond to one or more types of petroleum and / or renewable feedstocks with a suitable boiling range for thermal cracking, such as in a coker. The amount of plastic waste feedstock in the combination raw material may correspond to 1% to 50% by weight, 3% to 50% by weight, 10% to 50% by weight, 25% to 50% by weight, 1% to 25% by weight, 3% to 25% by weight, 10% to 25% by weight, or 3% to 15% by weight of the combination raw material. Conventional cracking raw materials may correspond to 50% to 99% by weight of the combination raw material of a coker.

[0026] In some embodiments, the cracking feedstock for co-processing with the plastic waste feedstock may correspond to a conventional petroleum feedstock having a relatively high boiling fraction, such as a heavy oil feedstock. For example, the cracking feedstock portion of the feed may have a T10 distillation point of 343°C or higher, or 371°C or higher. As used herein, the distillation point is determined in accordance with ASTM D86. If ASTM D86 is not suitable for characterizing the sample, ASTM 2887 may be used instead. In some embodiments, the coker feedstock has a T10 distillation point of 343°C to 650°C. Examples of suitable heavy oils for inclusion in the cracking feedstock include, but are not limited to, reduced petroleum crude; petroleum atmospheric distillation bottoms; petroleum vacuum distillation bottoms, or residual oil; asphalt; asphalt; petroleum asphalt; bitumen; other heavy hydrocarbon residues; tar sand oil; shale oil; or even coal slurry or coal liquefaction products, such as coal liquefaction bottoms. Such a feed will typically have at least 5 wt%, typically 5-50 wt% Conradson carbon (ASTM D189-165).In some embodiments, the feed is a petroleum vacuum residue.

[0027] Some examples of conventional petroleum feedstocks suitable for processing in a delayed coker or fluidized bed coker may have compositions and properties within the ranges listed in Table 1 below.

[0028] Table 1

[0029]

[0030]

[0031] In addition to petroleum feedstocks, renewable feedstocks derived from biomass with a suitable boiling range may also be used as part of the cracking feed. Such renewable feedstocks include feedstocks having a T10 boiling point of 340°C or greater and a T90 boiling point of 600°C or less. An example of a suitable renewable feedstock derived from biomass may be a pyrolysis oil feedstock derived at least in part from biomass.

[0032] In some specific embodiments, the plastic waste feed and conventional cracking feedstock (e.g., coker feedstock) are mixed before entering the thermal cracking environment to form a combined feedstock. In other embodiments, the plastic waste feed and conventional cracking feedstock are introduced into the thermal cracking environment separately. However, more generally, any convenient method for introducing both the plastic waste feed and the cracking feedstock into the coking environment can be used.

[0033] Prior to introduction into the coking environment, the feedstock (optionally in the form of a combined feedstock) is preheated according to one or more embodiments. Preheating the feedstock in one or more heating stages can raise the temperature of the feedstock to a mixing and storage temperature, to a temperature related to the cracking temperature, or to another convenient temperature.

[0034] In some embodiments, a portion of the preheating of the plastic waste feed can be performed by mixing the plastic waste feed with the cracking feed in a mixing tank and heating the mixture in the mixing tank. For example, the plastic waste feed and the cracking feed can be mixed in a storage heated stirring tank operating at 200°C to 325°C, or 275°C to 325°C. In some embodiments, tank stirring helps the plastic waste feed to be evenly dispersed into the residual oil and maintain the slurry suspension. Heating in the mixing tank provides heat to the combined feed before the combined feed is introduced into the cracking reaction environment. This can reduce or minimize additional cracking heat loads, which would otherwise require additional cracking heat loads to heat the plastic waste feed to the thermal cracking temperature. In addition to heating, the combined plastic waste feed and cracking feed can also be stripped using stripping gas in the mixing tank. Passing the stripping gas through the combined feed can help remove gases entrained in the combined feed.

[0035] According to some embodiments, yet another option may be to mix the plastic waste feed with the pyrolysis feed after the preheating furnace for the coker. In these embodiments, the pyrolysis feed may be heated to a higher temperature in the preheater, and then the plastic waste feed may be added to the preheated pyrolysis feed to heat the plastic waste feed.

[0036] In some embodiments, after mixing, the plastic waste in the combined raw material is re-sized to further reduce the particle size. For example, the combined raw material from the mixing tank is then physically processed to reduce the particle size of the plastic waste. In some embodiments, the maximum particle size of the combined raw material is reduced to about 5mm or less, 2mm or less, or 1mm or less. For example, the combined raw material is reduced to a particle size of 0.1mm to 5mm, 0.1mm to 2mm, or 0.1mm to 1mm. The example of physical processing may include the size adjustment of plastic waste, such as by crushing, chopping, shredding and grinding (including freezing grinding). In some embodiments, plastic waste is passed through a grinding device such as a roller mill to reduce the particle size. According to one or more embodiments, the physical processing in the roller mill can provide particles with a consistent particle size. After particle size adjustment (part icle sizing), the combined raw material is pumped to a coking environment, such as a thermal cracking reactor. In some embodiments, the combined raw material from the particle size adjustment is pumped and then preheated before thermal cracking.

[0037] In some embodiments, the plastic waste feed and / or the combined feedstock are atomized prior to introduction into the thermal cracking reactor. For example, an atomizing device (e.g., a nozzle assembly) may be used to atomize the plastic waste feed and / or the combined feedstock using a fluid such as steam, nitrogen, fuel gas, or natural gas. The fluid may be introduced in any suitable atomizing amount, including 0% to 5% by weight of the plastic waste feed and / or the combined feedstock.

[0038] Plastic waste pre-treatment

[0039] In various aspects, the plastic waste can be pre-treated before being transported to the coker reactor. Methods for pre-treating the plastic waste can include one or more of sorting, contaminant rejection, cleaning, particle size adjustment, and classification. One or more of these steps can be on-site in equipment directly connected to the thermal cracking unit, or in an upstream remote facility.

[0040] In some embodiments, pre-processing of plastic waste includes sorting the plastic waste to provide sorted plastic waste. Sorting includes, for example, removing non-plastic waste from the plastic waste. As previously noted, the plastic waste is not necessarily 100% plastic, so that the plastic waste can be sorted to remove non-plastic waste. In some embodiments, at least 5 weight %, at least 10 weight %, or at least 50 weight % of non-plastic waste is removed from the plastic waste. Sorting also includes, for example, sorting the plastic waste to provide two or more different grades of plastic waste. Sorting by grade can be based on chemical and / or physical parameters, including size, weight, density, volume, or a combination thereof.

[0041] In some embodiments, the pretreatment of plastic waste includes discarding pollutants from plastic waste to provide a purified plastic waste composition. Plastic waste may include various pollutants, such as chlorides, metals and minerals, etc., which may be problematic for subsequent processing. Specific examples of pollutants include, for example, sodium, mercury, bromine, fluorine, calcium, nitrogen, and oxygen. In some embodiments, thermal cracking may have specifications for one or more pollutants, thereby listing the amount of pollutants that may be present in plastic waste. Pollutant discarding includes removing at least a portion of pollutants from plastic waste to provide purified plastic waste. Pollutant discarding includes using any suitable technology to remove pollutants from plastic waste. Example technology includes using a magnetic field to remove metal pollutants from plastic waste. The magnetic field can be generated, for example, using a magnet or include a magnetic field generated by eddy currents. In some embodiments, plastic waste can be exposed to a magnetic field to remove at least a portion of metal pollutants from plastic waste. Another example for pollutant discarding includes applying a centripetal or centrifugal force to separate pollutants (such as metal pollutants) that are significantly different from other components of plastic waste. Another example technology for pollutant discarding includes using visual inspection or infrared devices. For example, an infrared sorting device may apply infrared light (e.g., in the near infrared spectrum of 0.75 to 1.4 microns) and use a spectrometer to detect reflected light that can be used to identify materials passing through the light and, if they do not meet preselected criteria, they can be discarded.

[0042] In some embodiments, discarding pollutants from the plastic waste composition includes cleaning the plastic waste composition to provide a clean plastic waste composition. For example, the plastic waste composition can be cleaned as follows: washing, rinsing and / or spraying the plastic waste composition with a solvent to remove at least a portion of the pollutants from the plastic waste composition. In some embodiments, the solvent includes water. In one or more embodiments, the solvent also includes a detergent, a caustic agent, or other solvent to enhance the washing process. Cleaning can also include mechanical stirring and / or scrubbing to remove pollutants attached to the plastic waste composition.

[0043] According to this embodiment, pollutant discarding removes at least a portion of pollutants from plastic waste. For example, at least 10 weight % of the pollutants in the plastic waste composition can be removed. In some embodiments, at least 50 weight %, at least 75 weight %, at least 90 weight % or more of the pollutants in the plastic waste composition can be removed.

[0044] In some embodiments, the pretreatment of the plastic waste composition includes the size adjustment of the plastic waste in the plastic waste composition to reduce its particle size. Size adjustment includes, for example, performing physical processing steps on the plastic waste composition to reduce its particle size in preparation for the thermal cracking environment. For example, having a small particle size can facilitate the transportation of solids and / or reduce the possibility of incomplete conversion in thermal cracking. In some embodiments, the plastic waste composition is sized so that it can be transported to the mixing chamber, for example, by pneumatic transport, belt conveyor or roller conveyor. In some embodiments, the plastic waste composition is sized to meet the minimum free path of the equipment. For example, the subsequent equipment may have restrictions that limit the particle size of the plastic waste. In some embodiments, the plastic waste is sized to facilitate the subsequent melting of solid particles into slurry. For example, a smaller particle size should have a reduced heat load required for melting. Examples of physical processing may include the size adjustment of the plastic waste composition, such as by crushing, chopping, shredding and grinding (including frozen grinding). In some embodiments, physical processing can be used to reduce the maximum particle size to 0.01 mm to 75 mm, 0.01 mm to 50 mm, 0.01 to 25 mm, 0.01 to 10 mm, 1 mm to 50 mm, 1 mm to 25 mm, 1 mm to 10 mm, 5 mm, or 0.1 mm to 5 mm, or 0.01 mm to 3 mm, or 0.1 mm to 3 mm, or 0.01 mm to 3 mm, or 0.1 mm to 3 mm, or 1 mm to 5 mm, or 1 mm to 3 mm. Optionally, after physical processing, the plastic waste composition can be sieved or filtered to remove larger particles. In some embodiments, sieving or filtering can be used to reduce the maximum particle size to 75 mm or less, 50 mm or less, 25 mm or less, 10 mm or less, or 5.0 mm or less.

[0045] Additional pre-treatment may be included, for example, in the melting of the plastic waste in the plastic waste composition in an extruder.After extrusion, the molten plastic waste composition may either be directly mixed with conventional cracking feedstocks and / or solvents, or the extruded plastic may be pelletized to form the desired particle size of the plastic waste feed.

[0046] In some embodiments, pretreatment of the plastic waste composition includes classification of the plastic waste. Classification includes, for example, analyzing the plastic waste composition by various methods or instruments to determine the characteristics of the plastic waste. The plastic waste composition is then classified based on the determined characteristics. For example, the plastic waste composition can be analyzed to determine the chemical composition, size, weight, density, volume and / or mass. The plastic waste composition can be analyzed using any suitable technique, including spectroscopy that can be used to determine one or more types of plastic in the plastic waste composition. In some embodiments, the plastic waste composition is classified based on size, and oversized plastic waste compositions are discarded, followed by subsequent blending with conventional cracking feeds.

[0047] In some embodiments, the pretreatment of the plastic waste composition includes blending the plastic waste composition. For example, two or more different plastic waste compositions can be blended to provide a mixed plastic waste composition, which can then be included in the plastic waste feed of the pyrolysis environment. The plastic waste composition can be distinguished based on different physical or chemical parameters, including contaminants, size, weight, density, volume, or a combination thereof. For example, a first plastic waste composition having a first polymer concentration of about 50% by weight of the first plastic waste composition can be blended with a second plastic waste composition having a second polymer concentration of about 50% by weight of the second plastic waste composition. Two or more plastic waste compositions can be selected to provide a mixed plastic waste composition that meets the specifications required by the pyrolysis environment, thereby allowing the use of a plastic waste composition that would otherwise be unusable due to the required specifications in the pyrolysis environment. For example, a plastic waste composition having a contaminant concentration, such as a chloride concentration, that exceeds the specifications can be blended with another plastic waste composition having a lower contaminant concentration to provide a mixed plastic waste composition within the specifications.

[0048] Figure 1 A method 100 for pre-treating plastic waste in accordance with an embodiment of the present disclosure is illustrated. As illustrated, the method 100 includes providing a plastic waste composition at box 102. The plastic waste composition from box 102 can be directed to an off-site waste treatment facility 104 or transported to an on-site waste treatment facility 106. At the on-site waste treatment facility 106, the plastic waste composition is received at an intake device, such as at box 118, and then pre-treated before being thermally cracked. At the off-site waste treatment facility 104, the plastic waste composition is pre-heated prior to being transported to the on-site waste treatment facility 106 for thermal cracking. For example, the plastic waste composition can be sorted, cleaned, and / or mixed to thermal cracking specifications at the off-site waste treatment facility 104. The off-site waste treatment facility 104 includes several different devices located off-site for pre-treating the plastic waste composition, such as Figure 1 As shown, but alternatively Figure 1 One or more of the devices may be located on-site. For example, the waste plastic composition may be optionally sent to an on-site waste treatment facility 106 for sorting, cleaning and / or mixing to meet thermal cracking specifications.

[0049] At the off-site waste treatment facility 104, at frame 108, a plastic waste composition is first received in sorting. Sorting includes, for example, removing non-plastic waste from plastic waste. Sorting also includes, for example, separating the plastic waste composition based on physical and / or chemical parameters. The sorted plastic waste composition may also have contaminants discarded at frame 110. According to one or more embodiments, in the contaminant discarding, at least a portion of the contaminants are removed from the plastic waste composition. The sorted plastic waste composition sorted at frame 108 may be directed to storage at frame 112. In storage, the sorted plastic waste composition may be stored in multiple storage containers such as feed silos or other suitable containers. Alternatively, the sorted plastic waste composition from the sorting at frame 108 may be directed to frame 114 for resizing to provide resized plastic waste, which is then directed to frame 112 for storage. Before storage, the resized plastic waste composition may also be cleaned by the contaminant discarding at frame 110. From storage, the plastic waste composition may be directed to frame 115 for mixing. In mixing, the plastic waste composition can be mixed, for example, to meet the thermal cracking specifications. For example, two or more different plastic waste compositions can be mixed to meet the thermal cracking specifications. From the mixing, the mixed plastic waste composition can be packaged in frame 116 to be transported to the thermal cracking facility. Any suitable technology that is conducive to transportation can be used to package the mixed plastic waste composition, such as bags, blocks, boxes, bucket trucks, rail vehicles or barges. In some embodiments, mixed plastic waste is transported in containers made of recycled materials or other materials suitable for feeding into the thermal cracking environment. For example, the transport container can be made of polymers such as polyethylene terephthalate (PET or PETE), high-density polyethylene (HDPE), low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE), polypropylene (PP), polystyrene (PS) and combinations thereof. In these embodiments, the mixed plastic waste composition will not be taken out from the transport container at the thermal cracking facility, but the mixed plastic waste composition and the transport container will be crushed together to form a plastic waste feed for the thermal cracking environment including the crushed transport container. In some embodiments, for example, the density of the plastic waste composition is increased to reduce the volume and thus maximize transportation. In some embodiments, the density of the plastic waste composition is reduced to 95 kg / m 3 Up to 1000kg / m 3 、300kg / m 3 Up to 1000kg / m 3 , or 400kg / m 3 Up to 500kg / m 3 .

[0050] At the on-site waste treatment facility 106, a plastic waste composition is received at frame 118. The plastic waste composition received at the on-site waste treatment facility 106 may be mixed plastic waste packaged at frame 116, plastic waste directly received from frame 102, or other suitable source plastic waste. The on-site waste treatment facility 106 is at the site of the pyrolysis unit. Upon receipt, the plastic waste composition may be weighed or otherwise processed to enter the facility. According to one or more embodiments, from receiving at frame 118, the plastic waste composition is transported by particle transport at frame 120 for further pretreatment. Any suitable technology for particle transport can be used to transport the plastic waste composition, including dry or wet transport. Examples of suitable transport mechanisms include, for example, pneumatic transport, belt conveyor, crane and / or roller conveyor. In some embodiments, the dry plastic waste composition uses pneumatic transport, while the wet plastic waste uses mechanical transport, such as belt, conveyor belt, roller and / or crane. Wet transport includes screw, belt, traction conveyor belt, bucket elevator, slideway and silo, etc. For example, in the case where the plastic waste includes liquids, such as water or hydrocarbon wetted plastic waste, wet transportation is suitable. In the illustrated embodiment, the plastic waste composition is transported to storage and blending at frame 122. For example, the plastic waste composition can be stored and blended with additional plastic waste, such as to meet thermal cracking specifications. The plastic waste composition can be blended with additional plastic waste compositions before or after storage. From frame 122, the plastic waste composition can either be sent to the particle size adjustment and classification at frame 124, or the pollutant discarding at frame 126. In the pollutant discarding, at least a portion of the pollutants can be removed from the plastic waste composition before the particle size adjustment and classification at frame 124. According to some embodiments, in the particle size adjustment and classification, the plastic waste composition is further adjusted to a reduced particle size. According to some embodiments, in the particle size adjustment and classification, the plastic waste composition can also be analyzed, such as determining the characteristics of the plastic waste composition. In some embodiments, from frame 126, at least a portion of the plastic waste can be sent to a thermal cracking environment. The plastic waste composition can be a composition directly fed to a coker and / or mixed with conventional cracking raw materials. In an alternative embodiment, at least a portion of the plastic waste composition may be preheated at frame 128. Preheating may reduce or minimize additional pyrolysis loads that would otherwise be required to heat the plastic waste feed. In some embodiments, preheating may, for example, melt or otherwise soften the plastic waste. In some embodiments, preheating includes melting the plastic in an extruder. After extrusion, the molten plastic waste may be fed into the thermal pyrolysis environment, for example either directly or first mixed with conventional pyrolysis feedstock. In some embodiments, the preheated plastic waste composition may be further discarded of contaminants at frame 126 before being fed into the thermal pyrolysis environment to remove at least a portion of the contaminants from the plastic waste composition.

[0051] In some embodiments, the pollutants are measured and then used for feedstock control of the plastic waste feed of the thermal cracking reactor. For example, the plastic waste feed can be adjusted in response to the measured pollutant concentration. The regulation of the plastic waste feed includes, for example, changing the composition and / or feed rate of the plastic waste feed. For example, the amount of one or more plastic waste compositions can be changed (e.g., increased or decreased) in response to the pollutant concentration. By way of example, the feed rate of the plastic waste feed can be reduced in response to the pollutant concentration. Any suitable technology can be used for the measured pollutants, including, for example, sampling with a laboratory analysis or an online analyzer. In a particular embodiment, the pollutants are measured in a specific portion of the cracking product or the cracking product. For example, the pollutants can be measured in the coker fractionator overhead gas stream (e.g., ethylene and lighter, or pentane and lighter); in the coker liquid products from the fractionator (which may include naphtha, kerosene, light coker gas oil, and heavy coker gas oil, which are limited by the boiling range of the products set by downstream processing); and / or in the top pumping loop after contacting the coker product vapor or in the acidic water condensed from the top of the coker fractionator. The pollutant concentration can also be measured in any washed gas stream from the combined coker feed before the coker reactor from the pretreatment step. These potential pollutants can be organic and inorganic halides, including chlorine, fluorine, bromine, iodine. It can also include arsenic compounds, mercury or mercury compounds, as well as aldehydes and organic acids. The pollutants in the coker product can be different compounds in the coker reactor feed. Additional pollutants in the cracked products (e.g., cracked gas) that can be traced back to the feed quality also include NOx, carbon monoxide, and carbon dioxide. Additionally, sodium accumulation on circulating coke, such as fluid cokers and flexicokers, can be measured.

[0052] Plastic waste pyrolysis

[0053] According to one or more embodiments, the plastic waste feed is cracked to produce more valuable cracked products. Thermal cracking is a process in which larger molecules are broken to produce smaller more useful molecules. For example, a thermal cracking process includes thermally cracking long chain hydrocarbons (or other long chain molecules) into shorter chain molecules. Examples of suitable thermal cracking processes include coking, visbreaking, and pyrolysis.

[0054] In some embodiments, the plastic waste feed is heated until molten, for example, to 150° C. to 325° C. or 275° C. to 325° C. Contaminants can then be at least partially removed (e.g., filtered) from the molten plastic waste feed, which is then directly injected into a cleavage reactor that receives a conventional cleavage feedstock through a separate feed system. In the cleavage reactor, the plastic waste feedstock and the conventional cleavage feedstock are co-processed to produce a valuable cleavage product.

[0055] In some embodiments, the plastic waste feed is heated until molten, for example, to 150° C. to 325° C. or 275° C. to 325° C. Contaminants can then be at least partially removed (e.g., filtered) from the molten plastic waste, and the molten plastic waste feed is then mixed with a conventional pyrolysis feedstock, and the combined feedstock is injected into a pyrolysis reactor. In the pyrolysis reactor, the plastic waste feedstock and the conventional pyrolysis feedstock are processed together to produce valuable pyrolysis products.

[0056] In some embodiments, the plastic waste feed is heated until molten, for example, to 150°C to 325°C or 275°C to 325°C. Contaminants can then be at least partially removed (e.g., filtered) from the molten plastic waste feed, which is then introduced into a heated mixing chamber together with a carrier fluid. In the mixing chamber, the molten plastic waste feed and the carrier fluid are mixed to produce a mixed feed. In some embodiments, the mixing chamber is heated. The mixed feed can be further heated and / or physically processed to reduce particle size before being injected into the cracking reactor.

[0057] In some embodiments, the plastic waste feed is stored (e.g., under ambient conditions) and then physically transported to a mixing chamber without melting. In the mixing chamber, the plastic waste feed and a carrier fluid are mixed to produce a mixed feed. In some embodiments, the mixing chamber is heated. The mixed feed can be further heated and / or physically processed to reduce particle size before being injected into the thermal cracking reactor.

[0058] Figure 2 An example system 200 for plastic waste co-processing is illustrated. As illustrated, the system 200 includes a plastic waste supply 202 and a conventional cracker feedstock supply 204. The plastic waste supply 202 may provide any suitable plastic waste composition suitable for use as a plastic waste feed, including from Figure 1 The plastic waste composition of process 100 shown above. Figure 2 However, the plastic waste feed can be preheated (e.g. Figure 1128 of the invention). As illustrated, a plastic waste feed comprising a plastic waste composition is provided from a plastic waste supply 202 to a mixing chamber 208 via a pipeline 206. In some embodiments, the plastic waste feed provided to the mixing chamber 208 is melted or otherwise preheated. A carrier fluid (e.g., a conventional cracker feed or other solvent) is also supplied to the mixing chamber 208 via a pipeline 210. In some embodiments, the carrier fluid is preheated. In some embodiments, the carrier fluid is a conventional coker feed supplied from a conventional coker feed supply 204, which may be supplied to a preheater 213, for example, via a pipeline 212, and then the preheated conventional cracking feed is supplied to the mixing chamber 208. In the mixing chamber 208, the plastic waste feed and the conventional cracker feed are mixed to form a combined feed. In some embodiments, the mixture in the mixing chamber 208 is heated to, for example, 150°C to 325°C or 275°C to 325°C. Tank agitation helps to evenly disperse the plastic waste into the mixture and maintain the slurry in suspension.

[0059] In the illustrated embodiment, the combined feed of the plastic waste feed and the conventional cracker feed is then provided to a particle size adjuster 216 via line 214. In the particle size adjuster 216, the particle size of the plastic waste feed is further reduced. The particle size adjuster 216 uses any suitable technology to adjust the combined feed size, including, for example, crushing, chopping, shredding and grinding (including frozen grinding). The combined feed size can be adjusted to provide, for example, a maximum particle size of 5 mm or less, 2 mm or less, or 1 mm or less. In some embodiments, the particle size adjuster 216 includes a grinding device such as a roller mill. The combined feed is then pumped to a combined feed preheater 222 via line 218 with a pump 220 and then fed to a cracking reactor 226 via line 224. The combined feed preheater 222 heats the combined feed, for example, to a temperature of 150° C. to 370° C. The combined feed preheater 222 can be any suitable type of heater, including, for example, a heat exchanger or an electric heater. In some embodiments, the combined feed is preheated by direct injection of hot oil. In some embodiments, the combined feed is preheated to melt the plastic waste and provide a combined feed having a viscosity of 2000 centipoise, 1000 centipoise or less. For example, the preheated combined feed causes at least 50% by weight of the plastic waste supplied to the cracking reactor 226 to melt. In some embodiments, 50%, 60%, 70%, 80%, 90%, 95% or more of the plastic waste supplied to the cracking reactor 226 melts. In some embodiments, plastic waste is preheated in the combined feed preheater 222 without melting, for example, 50%, 60%, 70%, 80%, 90%, 95% or more of the plastic waste supplied to the cracking reactor 226 is in solid form.

[0060] In the illustrated embodiment, a portion of the conventional cracker feed is supplied directly to the cracking reactor 226. As illustrated, a portion of the conventional cracker feed may be supplied directly to the cracking reactor 226 from the preheater 213 via line 228. In the illustrated embodiment, a portion of the plastic waste feed is also supplied directly to the cracking reactor 226 via line 230. This portion of the plastic waste feed may be in solid form or may be at least partially melted prior to being added to the cracking reactor 226. In some embodiments, at least some of the plastic waste feed is directed via line 232 for combination with the conventional cracker feed in line 228, wherein the combined feed is fed to the cracking reactor 226 via line 228.

[0061] In the cracking reactor 226, the plastic waste feed and the conventional cracking feedstock are cracked to produce more valuable cracking products including various hydrocarbons. In some embodiments, the cracking products include cracking effluents, which may include gas, liquid, or mixtures thereof. In the illustrated embodiment, the cracking effluent is provided to the separator 236 via pipeline 234. Although shown as one device, the separator 236 may include several device operations such as steam stripping, distillation, and quenching, such as to separate the effluent from the cracking into various fractions, including but not limited to a fuel gas fraction 238, a naphtha fraction 240, a distillate fraction 242, and / or a gas oil fraction 244. The specific fractions produced from the separator 236 may vary according to the needs of a specific application.

[0062] In some embodiments, analyzer 246a-246f is used to carry out the raw material control of plastic waste feed.As explained, analyzer 246a-246f can be placed on one or more feed and / or product pipelines, for the measurement of various components in feed and / or product pipelines.In the illustrated embodiment, analyzer 246a is placed on pipeline 224 to measure the combined raw material of plastic waste and conventional cracking raw material, and analyzer 246b is placed on the pipeline 230 that plastic waste is directly injected into cracking reactor 226.In addition, the illustrated embodiment is included in the analyzer 246d-246g on each product pipeline (comprising fuel gas fraction 238, naphtha fraction 240, distillate fraction 242 and / or gas oil fraction 244).Although not shown, other analyzer can be placed, for example, to measure pollutants, for example, total halides or hydrogen chloride from the acidic water of fractionator.

[0063] In some embodiments, analyzers 246a-246f measure pollutants such as chlorides or other halides, such as fluorine and bromine. For example, in response to the pollutant concentration measurement results from one or more analyzers, the plastic waste feed is adjusted. This adjustment includes adjusting the plastic waste ratio and / or adjusting one or more of the composition of the plastic waste feed. The plastic waste ratio includes the ratio of plastic waste to conventional cracking raw materials. For example, if one or more pollutants are high in analyzers 246a-246f, the plastic waste ratio can be reduced so that less plastic waste with pollutants is processed. Reducing the plastic waste ratio includes, for example, reducing the feed rate of plastic waste, such as reducing the rate of direct plastic waste injection or the rate of plastic waste combined with conventional cracker raw materials. In other embodiments, the plastic feed includes one or more plastic waste compositions, wherein the specific composition of one or more plastic waste compositions is adjusted in response to the pollutant concentration measurement results. For example, if the concentration of a specific pollutant is too high, the plastic waste composition with the specific pollutant can be adjusted so that its feed rate is reduced or potentially even stopped to control the pollutant level. In some embodiments, the concentration of the plastic composition having chlorine in the plastic waste feed can be adjusted in response to measuring the chlorine concentration, for example, the concentration can be reduced.

[0064] One example of thermal cracking of plastic waste feed includes coking, in which longer chain molecules are thermally cracked to produce shorter chain molecules, with excess carbon left behind in the form of petroleum coke. Coking processes in modern refineries can be generally classified as delayed coking or fluidized bed coking. Fluidized bed coking is a petroleum refining process in which a heavy petroleum feed, typically the non-distillable residue (residue) from the fractionation of heavy oil, is converted into lighter, more useful products by thermal decomposition (coking) at elevated reaction temperatures, typically 480°C to 590°C and in most cases 500°C-550°C. Exemplary heavy oils suitable for processing by the fluid coking process include heavy atmospheric residues, petroleum decompression distillation bottoms, aromatic extracts, bitumen, and petroleum bitumen from tar sands, tar pits and asphalt lakes in Canada (Athabasca, Alberta), Trinidad, Southern California (La Brea (Los Angeles)), McKittrick (Bakersfield, California), Carpinteria (Santa Barbara County, California), Lake Bermudez (Venezuela), and similar deposits such as those found in Texas, Peru, Iran, Russia and Poland.

[0065] Fluidized coking is carried out in an apparatus having a large reactor containing hot coke particles which are maintained under fluidized conditions at the desired reaction temperature with steam injected at the bottom of the vessel, wherein the average direction of motion of the coke particles is downward through the bed. In a particular embodiment, the combined feedstock is heated to a pumpable temperature, typically in the range of 350°C to 400°C, mixed with atomizing steam, and fed through a plurality of feed nozzles arranged in several consecutive levels in the reactor. Steam is injected into the stripping section at the bottom of the reactor and passes upward through the coke particles, which descend through the dense phase of the fluidized bed in the main part of the reactor above the stripping section. Part of the feed liquid coats the coke particles in the fluidized bed and is subsequently cracked into a solid coke layer and releases lighter products as gas or vaporized liquid. The residence time of the feed in the coking zone (where the temperature is suitable for thermal cracking) is on the order of 1 second to 30 seconds. The reactor pressure is relatively low in order to facilitate the gasification of hydrocarbon vapors, which pass upward from the dense phase of the fluidized bed in the coking zone into the dilute phase and into the cyclone separator at the top of the coking zone, where most of the entrained solids are separated from the gas phase by centrifugal force in one or more cyclones and returned to the dense fluidized bed through the cyclone legs by gravity. The mixture of hydrocarbon vapor and steam from the reactor is then discharged from the cyclone gas outlet to the scrubber section in the booster chamber located above the coking zone and separated from it by a partition. It is quenched in the scrubber section by contact with liquid descending from the shed. A pumping circulation loop circulates the condensate to an external cooler and returns to the top shed row of the scrubber section to provide cooling for the quenching and condensation of the heaviest fraction of the liquid product. This heavy fraction is usually recycled to disappearance by feeding back to the coking zone in the reactor.

[0066] During the fluidized coking process, a coking feedstock preheated to a temperature at which it can flow and pump is introduced into the coking reactor toward the top of the reactor vessel through an injection nozzle configured to produce a feed spray that enters a bed of fluidized coke particles in the vessel. The temperature in the coking zone of the reactor is typically in the range of 450°C to 650°C, and the pressure is maintained at a relatively low level, typically in the range of 0 kPag to 700 kPag and most often 35 kPag-320 kPag, so as to promote rapid drying of the coke particles, thereby preventing the formation of sticky, adherent high molecular weight hydrocarbon deposits on the particles that can cause reactor fouling. In some embodiments, the temperature in the coking zone may be 450°C to 600°C, or 450°C to 550°C. Conditions may be selected so that a desired amount of feedstock conversion occurs in the fluidized bed reactor. For example, conditions may be selected to achieve at least 10 wt% conversion relative to 343°C (or 371°C), or at least 20 wt% conversion relative to 343°C (or 371°C), or at least 40 wt% conversion relative to 343°C (or 371°C), such as up to 80 wt% conversion or possibly even higher. The light hydrocarbon products of the coking (thermal cracking) reaction are vaporized, mixed with the fluidizing steam and passed upward through the dense phase of the fluidized bed into the dilute phase region above the dense fluidized bed of coke particles. This mixture of vaporized hydrocarbon products formed in the coking reaction flows upward through the dilute phase with steam at a critical velocity of about 1 to 2 m / s (~3 to 6 ft / s), entraining some fine coke solid particles separated from the cracking vapor in the reactor cyclone separator as described above. In embodiments where steam is used as a fluidizing agent, the weight of steam introduced into the reactor may be selected relative to the weight of the feedstock introduced into the reactor. For example, the mass flow rate of steam entering the reactor may correspond to 6.0% of the mass flow rate of the raw material, or 8.0% or more, such as up to 10% or possibly even higher. If an activated light hydrocarbon stream is used as part of the stripping and / or fluidizing gas in the reactor, the amount of steam can be potentially reduced. In such an embodiment, the mass flow rate of steam may correspond to 6.0% or less, or 5.0% or less, or 4.0% or less, or 3.0% or less of the mass flow rate of the raw material. Optionally, in some embodiments, the mass flow rate of steam may be lower, such as corresponding to 1.0% or less, or 0.8% or less, or 0.6% or less of the mass flow rate of the raw material, such as down to substantially all of the steam being replaced by activated light hydrocarbon steam. The cracked hydrocarbon vapor leaves the cyclone separator and enters the washing section of the reactor and then to product fractionation and recovery.

[0067] In a typical fluid coking process, the coke particles formed in the coking zone are carried downward in the reactor and leave the bottom of the reactor vessel through a stripping section where they are exposed to steam to remove occluded hydrocarbons. The solid coke from the reactor, consisting mainly of carbon with lesser amounts of hydrogen, sulfur, nitrogen and trace amounts of vanadium, nickel, iron and other elements derived from the feed, passes through the stripper and leaves the reactor vessel to a burner or heater where the solid coke is partially combusted with air in a fluidized bed to raise its temperature from 480°C to 700°C, thereby supplying the heat required for the endothermic coking reaction, after which a portion of the hot coke particles is recycled to the fluidized bed reaction zone to transfer heat to the reactor and serve as nuclei for coke formation. The remainder is extracted as a coke product. The net coke yield is only 65% ​​of that produced by delayed coking.

[0068] For a coking process including a gasification zone, the cracking process is carried out in a reactor, with the coke particles passing downwardly through the coking zone, through a stripping zone, where occluded hydrocarbons are stripped by an ascending stream of fluidizing gas (steam). They then leave the coking reactor and pass to a gasification reactor (gasifier), which contains a fluidized bed of solid particles and operates at a temperature higher than that of the coking zone of the reactor. In the gasifier, the coke particles are converted into a fuel gas comprising carbon monoxide and hydrogen by reacting with steam and an oxygen-containing gas at elevated temperatures.

[0069] The gasification zone is typically maintained at a high temperature in the range of 850°C-1,000°C and a pressure in the range of 0kPag-1000kPag, preferably 200kPag-400kPag. Steam and oxygen-containing gas are introduced to provide a source of oxygen for fluidization and gasification. In some embodiments, the oxygen-containing gas may be air. In other embodiments, the oxygen-containing gas may have a low nitrogen content, such as oxygen from an air separation unit or another oxygen stream (including 95% by volume or more, or 98% by volume or more of oxygen) sent to the gasifier for reaction with solid particles in the coking zone, the solid particles including coke deposited thereon. In embodiments in which the oxygen-containing gas has a low nitrogen content, a separate diluent stream, such as a recycled CO2 or H2S stream derived from the fuel gas produced by the gasifier, may also be fed to the gasifier.

[0070] In the gasification zone, the reaction between coke and steam and oxygen-containing gas produces fuel gas containing hydrogen and carbon monoxide and partially gasified residual coke product. The conditions in the gasifier are selected accordingly to produce these products. Steam and oxygen rate (and any optional CO2 rate) will depend on the rate at which cold coke enters from the reactor, and to a lesser extent on the composition of coke, which in turn will vary according to the composition of the heavy oil feed and the severity of the cracking conditions in the reactor, wherein these are selected according to the range of feed and desired liquid products. In some embodiments, the fuel gas product from the gasifier contains entrained coke solids and these are removed by cyclone separators or other separation techniques in the gasifier section of the device. Suitable cyclone separators include internal cyclone separators in the main gasifier container itself or external cyclone separators in separate smaller containers, as described below. The fuel gas product is taken out from the gasifier cyclone separator as overhead. The resulting partially gasified solids are removed from the gasifier and introduced directly into the coking zone of the coking reactor at a level located in the dilute phase above the lower dense phase.

[0071] In some embodiments, coking conditions may be selected to provide a desired amount of conversion relative to 343° C. Typically, the desired amount of conversion may correspond to 10 wt % or more, or 50 wt % or more, or 80 wt % or more, e.g., up to substantially complete conversion relative to 343° C. feedstock.

[0072] Volatile products from the coke drum are directed away from the process for further processing. For example, volatiles may be introduced into a coker fractionator for distillation and recovery of coker gas, coker naphtha, light gas oil, and heavy gas oil. Such fractions (usually but not always after upgrading) may be used to blend fuel and lubricant products, such as motor gasoline, motor diesel, fuel oil, and lubricant oil. Upgrading may include separation, heteroatom removal via hydroprocessing and non-hydroprocessing processes, dearomatization, solvent extraction, and the like. The process is compatible with such a process, wherein at least a portion of the heavy coker gas oil present in the product stream introduced into the coker fractionator is captured for recycling and combined with fresh feed (coker feed component), thereby forming a coker heater or coke oven charge. The combined feed ratio ("CFR") is the volume ratio of the furnace feed (fresh feed plus recycled oil) to the fresh feed of a continuous fluidized coker operation. Fluid coking operations typically employ recycle of 5% to 35% by volume (CFR of 1.05 to 1.35). In some embodiments, there may be no recycle, and sometimes in dedicated applications, the recycle may be up to 200%.

[0073] Flexicoking developed by Exxon Research and Engineering CompanyTM The process is a type of fluid coking process operated in an apparatus that includes a reactor and a heater, and also includes a gasifier for gasifying the coke product (by reacting with an air / steam mixture to form a low heating value fuel gas). The stream of coke is sent from the heater to the gasifier, where all but a small portion of the coke is gasified to a low BTU gas (~120 BTU / standard cubic foot) by adding steam and air in a fluidized bed in an oxygen-deficient environment to form a fuel gas comprising carbon monoxide and hydrogen. In conventional Flexicoking TM In the configuration, the fuel gas product from the gasifier containing entrained coke particles is returned to the heater to provide most of the heat required for thermal cracking in the reactor, the balance of the reactor heat requirement being supplied by combustion in the heater. A small amount of clean coke (1% of the feed) is withdrawn from the heater to remove metals and ash from the system. Liquid yields and properties are comparable to those from fluid coking. The fuel gas product is withdrawn from the heater after separation in internal cyclones, which return the coke particles through their legs.

[0074] In this description, the term "Flexicoking" (a trademark of ExxonMobile Research and Engineering Company) is used to name a fluidized coking process in which a heavy petroleum feed is subjected to thermal cracking in a fluidized bed of heated solid particles to produce lower molecular weight and boiling point hydrocarbons and coke as a byproduct, which is deposited on the solid particles in the fluidized bed. Reference to a fluidized coker is intended to include conventional fluidized cokers as well as flexicokers. The resulting coke can then be converted to fuel gas by contact with steam and an oxygen-containing gas at elevated temperatures in a gasification reactor (gasifier). This type of configuration may be more generally referred to as the integration of fluidized bed coking and gasification. Figure 3 and 4 An example of a fluid coking reactor including a gasifier is provided.

[0075] Figure 3 An example of a flexible coker apparatus (i.e., a system including a gasifier thermally integrated with a fluidized bed coker) is shown having three reaction vessels: a reactor, a heater, and a gasifier. The coking system 300 includes a coker reactor 302 having a coking zone and its associated stripping and washing sections (not shown separately), a heater 304, and a gasifier 306. A cracking feedstock, which may be a plastic waste feedstock (or a combination of a plastic waste feedstock and a conventional cracking feedstock), is introduced into the coking system 300 via line 308 and cracked hydrocarbon products are withdrawn via line 310. Although Figure 3A combined feedstock is shown, but example embodiments also include separate introduction of conventional cracking feedstock and plastic waste feed into the coker reactor 302. Fluidizing and stripping steam is supplied via line 312. Cold coke is taken out from the stripping section at the bottom of the coker reactor 302 by means of line 314 and sent to the heater 304. The term "cold" as applied to the temperature at which the coke is withdrawn is, of course, obviously relative, as it is much higher than ambient temperature at the operating temperature of the stripping section. The hot coke is circulated from the coker reactor 304 to the coker reactor 302 via line 316. The coke from the heater 304 is transferred to the gasifier 306 via line 318, and the hot, partially gasified coke particles are circulated from the gasifier back to the heater 304 via line 320. Excess coke is withdrawn from the heater 304 via line 322. In a conventional configuration, the gasifier 306 is provided with a supply of steam and air via line 324, and hot fuel gas is withdrawn from the gasifier via line 326 and sent to a heater. In some alternative embodiments, instead of supplying air to the gasifier 306 via line 324, an oxygen stream having a purity of 95% by volume or greater, such as an oxygen stream from an air separation unit, may be provided. In such an embodiment, in addition to supplying the oxygen stream, an additional dilution gas stream may be supplied via line 328. The additional dilution gas may correspond to, for example, CO2 separated from the fuel gas produced during the gasification process. The fuel gas is withdrawn from the device via line 330 on the heater; coke fines are removed from the fuel gas in a heater cyclone system 332, which includes primary and secondary cyclones connected in series, with a feed leg for returning the separated fines to a fluidized bed in the heater. The fuel gas from line 330 may then undergo further processing. For example, in some embodiments, the fuel gas from line 330 can be sent to a separation stage to separate CO2 (and / or H2S). This can result in a stream with an increased syngas concentration, which can then be sent to a conversion stage to convert the syngas to methanol.

[0076] It should be noted that in some optional embodiments, the heater cyclone system 332 may be located in a separate container (not shown) rather than in the heater 304. In such aspects, the pipeline 330 may extract the fuel gas from the separate container, and the pipeline 322 for removing excess coke may correspond to the pipeline for transporting coke fines away from the separate container. These coke fines and / or other partially gasified coke particles discharged from the heater (or gasifier) ​​may have an increased metal content relative to the raw material. For example, the weight percentage of metal in the coke particles discharged from the system (relative to the weight of the discharged particles) may be greater than the weight percentage of metal in the raw material (relative to the weight of the raw material). In other words, the metal from the raw material is concentrated in the discharged coke particles. Because the gasifier conditions do not produce slag, the discharged coke particles correspond to a mechanism for removing metals from the coker / gasifier environment. In some embodiments, the metal may correspond to a combination of nickel, vanadium and / or iron. Additionally or alternatively, the gasifier conditions may be such that substantially no metal oxides are deposited on the interior walls of the gasifier, such as less than 0.1 wt. %, or less than 0.01 wt. % of the metals present in the feedstock introduced into the coker / gasifier system.

[0077] In such Figure 3 In the configuration of FIG. 3 , the system elements shown in the figure can be characterized based on the fluid communication between the elements. For example, the coker reactor 302 is directly in fluid communication with the heater 304. The coker reactor 302 is also indirectly in fluid communication with the gasifier 306 via the heater 304.

[0078] As an alternative, the integration of the fluidized bed coker with the gasifier can also be achieved without the use of an intermediate heater. In such an alternative aspect, the cold coke from the reactor can be transferred directly to the gasifier. This transfer will in almost all cases be unambiguously direct, with one end of the tubular transfer line being connected to the coke outlet of the reactor and its other end being connected to the coke inlet of the gasifier, without an intermediate reaction vessel, i.e. a heater. However, the presence of means other than a heater, such as a lift gas inlet, etc., is not excluded. Similarly, although the hot, partially gasified coke particles from the gasifier are directly returned from the gasifier to the reactor, this only means that there is no intermediate reaction vessel, i.e. a heater, as in a conventional three-vessel Flexicokar. TM An intermediate heater is provided, while other devices may be present between the gasifier and the reactor, such as a gas lift inlet and outlet.

[0079] Figure 4 An example showing the integration of a fluidized bed coker with a gasifier but without a separate heater vessel. Figure 5 In the configuration shown in , the cyclone separator used to separate the fuel gas from the catalyst fines is located in a separate vessel. In other aspects, the cyclone separator can be included in the main gasifier vessel 404.

[0080] exist Figure 4 In the configuration shown in , the coker system 400 includes a coker reactor 402, a main gasifier vessel 404, and a separator vessel 406. The cracking feed is introduced into the coker reactor 402 via line 408 and the fluidizing / stripping gas via line 410; the cracked hydrocarbon products are removed via line 412. The coking feed includes a plastic waste feed optionally combined with a conventional cracking feed (e.g., a heavy oil feed). The plastic waste feed may be introduced into the coker reactor 402 alone or in combination with, for example, a conventional cracking feed. The cold stripping coke is transported directly from the coker reactor 402 to the main gasifier vessel 404 via line 414, while the hot coke is returned to the reactor in line 416. Steam and oxygen are supplied via line 418. A gas stream containing coke fines is transported to the separator vessel 406 via line 420 connected to the gas outlet of the main gasifier vessel 404. Fines are separated from the gas stream in a cyclone system 422, which includes primary and secondary cyclones connected in series, with a dipleg returning the separated fines to the separator vessel. The separated fines are then returned to the main gasifier vessel 404 via return line 424 and a fuel gas product is taken out via line 426. Coke is removed from the separator via line 428. The fuel gas from line 426 may then undergo further processing to separate CO2 (and / or H2S) and convert the syngas to methanol.

[0081] Cokers and gasifiers can be operated according to the parameters required by the desired coking process. Thus, the heavy oil feed in the cracking feedstock will typically be a heavy (high boiling) atmospheric petroleum residue; petroleum atmospheric distillation bottoms; petroleum vacuum distillation bottoms, or residue; asphalt; bitumen; petroleum asphalt; other heavy hydrocarbon residues; tar sand oil; shale oil; or even coal slurry or coal liquefaction products, such as coal liquefaction bottoms. Such feeds will typically have at least 5% by weight, typically 5-50% by weight of Conradson carbon residue (ASTM D189-165). In some embodiments, the cracking feedstock is a petroleum vacuum residue.

[0082] Delayed coking is another coking process for the thermal conversion of heavy oils such as petroleum residue (also referred to as "residual oil") to produce liquid and vapor hydrocarbon products and coke. In a specific embodiment, the raw material of the plastic waste feed optionally combined with the conventional cracking feed is subjected to delayed coking to produce liquid and vapor hydrocarbon products and coke. In some embodiments, the conventional hydrocarbon feedstock includes residual oil from heavy and / or acidic (high sulfur) crude oil. Delayed coking of the feedstock is carried out by converting part of the feedstock into more valuable hydrocarbon products. The resulting coke has a certain value as a fuel (fuel-grade coke), an electrode for aluminum manufacturing (anode-grade electrode), etc., according to its grade.

[0083] Typically, the feedstock is pumped to a preheater where it is preheated, for example, to a temperature of 480°C to 520°C. The preheated feed is introduced into the coking zone, typically a vertically oriented insulated coker vessel, such as a drum, through an inlet at the bottom of the drum. The pressure in the drum is typically relatively low, for example, 100 kPa-g to 550 kPa-g, or 100 kPa-g to 240 kPa-g, so that volatiles are removed at the top. The drum typically operates at temperatures between about 400°C and 445°C, but can be as high as 475°C. The hot feed is thermally cracked in the coke drum over a period of time (the "coking time"), releasing volatiles consisting primarily of hydrocarbon products, which continuously rise through a coke bed consisting of channels, holes and passages and are collected at the top. The volatile products are introduced into a coker fractionator for distillation and recovery of coker gases, gasoline boiling range materials such as coker naphtha, light gas oil, and heavy gas oil. In an embodiment, a portion of the heavy coker gas oil present in the product stream introduced into the coker fractionator can be captured for recycling and combined with fresh feed (coker feed component), thereby forming a coker heater or coke oven feed. In addition to volatile products, the process also causes coke to accumulate in the drum. When the coke drum is full of coke, the heated feed is transferred to another drum and the hydrocarbon vapors are purged from the coke drum using steam. The drum is then quenched with water to reduce the temperature to 95°C to 150°C, after which the water is drained. When the drainage step is completed, the drum is opened and the coke is removed by drilling and / or cutting using high-speed water jets ("hydraulic decoking").

[0084] Figure 5An example delayed coking system 500 is illustrated. In the illustrated embodiment, a feedstock 502 (which may be preheated) comprising a plastic waste feed is fed into a coker fractionator 504. In some embodiments, the feedstock 502 also includes a conventional cracking feedstock, which may also be fed separately to the coker fractionator 504. In the illustrated embodiment, a fractionator effluent 506 comprising at least a portion of the plastic waste feedstock and / or the conventional cracking feedstock is withdrawn from the coker fractionator 504 and fed to a coker furnace 508. From the coker furnace 508, a preheated effluent 510 comprising preheated plastic waste feedstock and / or preheated conventional cracking feedstock is sent to a coking reactor 512, which includes, for example, a coking vessel or a coking drum. The preheated effluent 510 also includes, for example, a tower bottoms (or recycle). The coking reactor 512 is operated under coking conditions such that the preheated plastic waste feed / conventional cracking feedstock is thermally cracked in the coking reactor 512 for a period of time ("coking time"), releasing volatiles consisting primarily of hydrocarbon products, which continuously rise through a coke bed consisting of channels, holes and passages and are collected at the top as a coker effluent 514, which is sent to a coker fractionator 504. In the illustrated embodiment, the coker effluent 514 is separated into fractions in the coker fractionator 504, including but not limited to one or more of a coker gas fraction 518, a coker naphtha fraction 520, a coker distillate fraction 522, and a coker gas oil fraction 524. It should be understood that the separation of the coking products into fractions can occur in one or more vessels and / or in one or more different operations. As previously mentioned, coke accumulates in the coking reactor 512 (e.g., a coking vessel). A coke product 516 including coke is withdrawn from the coking reactor 512 .

[0085] Cleavage products

[0086] Coking of plastic waste feed alone or in combination with conventional cracking feedstock produces cracking products. In some embodiments, the cracking product includes a cracking effluent, which may include a gas, a liquid, or a mixture thereof. As discussed above, the cracking effluent may be fractionated or otherwise separated to form a desired product stream, such as fuel gas (e.g., C4 and light hydrocarbons), naphtha, distillate, and gas oil. Naphtha typically has a boiling point range of 80°C to 205°C. Distillate typically has a boiling point range of 205°C to 370°C. Gas oil typically has a boiling point range of 370°C to 595°C. In some embodiments, such as coking, the cracking product also includes coke. Because many plastic wastes have a relatively low sulfur content (compared to conventional coker feedstocks), the cracking product has a reduced sulfur content, and in some embodiments, the severity required for any subsequent desulfurization process (e.g., hydroprocessing) is therefore reduced.

[0087] The coke produced in the coking process is generally a carbonaceous solid material mainly composed of carbon. Because coke is produced by the co-processing of conventional cracking raw materials in the coker, it can also be referred to as petroleum coke or petroleum coke according to one or more embodiments. The coke yield is generally 20% to 40% by weight of the combined coker raw materials. However, because plastic waste can have a significantly higher atomic ratio of hydrogen to carbon, coking with plastic waste feed can produce a reduced or minimized amount of coke. The specific composition of coke depends on several factors, including a specific coking process, such as a delayed coker, or in some embodiments, coke includes carbon in an amount of 80% to 95% by weight based on the gross weight of coke. The additional components in the coke include hydrogen, nitrogen, sulfur and heavy metals, such as aluminum, boron, calcium, chromium, cobalt, iron, manganese, magnesium, molybdenum, nickel, potassium, silicon, sodium, titanium and / or vanadium.

[0088] In some embodiments, the cracker effluent is at least partially derived from polymeric materials in the plastic waste feed, such as polyolefins or other polymers (such as polystyrene). In some embodiments, monomers and / or polymers in and / or derived from one or more components in the cracker effluent are considered to be cyclic. For example, the cracker effluent includes circulating monomers derived from the cracking plastic waste feed. By way of other examples, the polymer of the cycle can be produced by one or more components of the cracker effluent. Advantageously, by attributing these monomers and / or polymers to the polymer in the plastic waste feed, such as by accounting, allocating and / or offsetting or replacing other hydrocarbons in the mass or energy balance in the coker system, these monomers and / or polymers are considered to be cyclic. In some embodiments, monomers and / or the polymer formed can be certified by third-party certification for their cyclicity. An example of such certification is the mass balance custody chain method proposed by international sustainable development and carbon certification.

[0089] Additional embodiments

[0090] Thus, the present disclosure may provide for recycling of plastic waste, which includes cracking a plastic waste feed to produce hydrocarbons.The methods and systems may include any of the various features disclosed herein, including one or more of the following statements.

[0091] Embodiment 1. A method for processing plastic waste, comprising: thermally cracking at least a plastic waste feed and a cracking feedstock to produce at least a cracking product comprising hydrocarbons, wherein the cracking feedstock has a T10 distillation point of 343°C or higher; measuring contaminant concentrations; and adjusting the plastic waste feed in response to the contaminant concentrations.

[0092] Embodiment 2. The method of embodiment 1, wherein the contaminant concentration is measured in a liquid separated from the cleavage product.

[0093] Embodiment 3. The method of embodiment 1, wherein the concentration of the pollutant is measured in the gas separated from the cracking product.

[0094] Embodiment 4. The method of Embodiment 1, wherein the contaminant concentration is the concentration of hydrogen chloride measured in the acidic water produced in the fractionator.

[0095] Embodiment 5. The method of Embodiment 1, wherein the contaminant concentration is the concentration of one or more organic halides.

[0096] Embodiment 6. The method of Embodiment 1, wherein the pollutant concentration is the concentration of one or more of NOx, carbon monoxide, or carbon dioxide in the cracking product or a separated fraction of the cracking product.

[0097] Embodiment 7. The method of Embodiment 1, wherein the contaminant concentration is a measurement of sodium accumulation in the coke produced in the thermal cracking step.

[0098] Embodiment 8. The method of Embodiment 1, wherein adjusting the plastic waste feed comprises adjusting a feed rate of the plastic waste feed to reduce a ratio of the plastic waste feed to the pyrolysis feedstock.

[0099] Embodiment 9. The method of Embodiment 1, wherein adjusting the plastic waste feed comprises changing the amount of one or more plastic waste compositions in the plastic waste feed.

[0100] Embodiment 10. The method of embodiment 1, wherein the plastic waste feed comprises one or more plastics classified as Plastic Identification Codes 1 to 7 by the Association of the Plastics Industry.

[0101] Embodiment 11. The method of Embodiment 1, wherein the cracking feedstock comprises petroleum vacuum residue.

[0102] Embodiment 12. The method of Embodiment 1, wherein the cracking feed has a T10 distillation point of 343°C to 650°C.

[0103] Embodiment 13. The method of Embodiment 1, wherein the plastic waste feed is fed into the cleavage reactor in the form of a combined feed of plastic waste feed and cleavage feed in an amount of about 0.1 wt % to about 25 wt %.

[0104] Embodiment 14. The method of Embodiment 1, wherein the step of thermal cracking comprises exposing the plastic waste feed and the cracking feedstock to coking conditions.

[0105] Embodiment 15. A method for processing plastic waste, comprising: physically processing a plastic waste feed to reduce the maximum particle size of the plastic waste feed; combining the plastic waste feed with a carrier fluid to form a combined feedstock; physically processing the combined feedstock to reduce the maximum particle size of solid particles in the combined feedstock; preheating the combined feedstock to cause melting of the solid particles in the combined feedstock; and thermally cracking the combined feedstock to produce at least a cracking product comprising hydrocarbons.

[0106] Embodiment 16. The method of Embodiment 15, further comprising preheating the plastic waste feed and preheating the carrier fluid.

[0107] Embodiment 17. The method of Embodiment 15, wherein the maximum particle size of the plastic waste feed is reduced to about 0.1 mm to about 75 mm during physical processing.

[0108] Embodiment 18. The method of Embodiment 15, wherein the maximum particle size of the solid particles in the combined feedstock is reduced to about 0.1 mm to about 1 mm.

[0109] Embodiment 19. The method of Embodiment 15, wherein the step of physically processing the combined feedstock to reduce the maximum particle size of solid particles in the combined feedstock comprises passing the combined feedstock through a ball mill.

[0110] Embodiment 20. The method of Embodiment 15, wherein the carrier fluid and the plastic waste feed are combined in a heated mixing chamber.

[0111] Embodiment 21. The method of Embodiment 15, wherein the carrier fluid comprises a cracked feedstock having a T10 distillation point of 343°C or higher.

[0112] Embodiment 22. The method of Embodiment 15, wherein the carrier fluid comprises petroleum vacuum residue.

[0113] Embodiment 23. The method of Embodiment 15, wherein the plastic waste feed comprises one or more plastics classified as Plastic Identification Codes 1 to 7 by the Association of the Plastics Industry.

[0114] Embodiment 24. The method of Embodiment 15, wherein the plastic waste feed is present in the combined feedstock in an amount from about 0.1 wt % to about 25 wt %.

[0115] Embodiment 25. The method of Embodiment 15, wherein the step of thermal cracking comprises exposing the combined feedstock to coking conditions.

[0116] Embodiment 26. A method for processing plastic waste, comprising: identifying target specifications required for a plastic waste feed; determining a mixture of at least two plastic waste compositions that meets the target specifications; mixing at least two plastic waste compositions to form a plastic waste feed; and at least thermally cracking the plastic waste feed and a cracking feed to produce at least a cracking product comprising hydrocarbons, wherein the cracking feed has a T10 distillation point of 343°C or higher.

[0117] Embodiment 27. The method of Embodiment 26, wherein the at least two plastic waste compositions comprise a first plastic waste composition that does not meet the target specification and a second plastic waste composition that meets the target specification.

[0118] Embodiment 28. The method of Embodiment 26, wherein the target specification includes pollutant concentration.

[0119] Embodiment 29. The method of Embodiment 26, wherein the target specification includes an upper limit on halide concentration.

[0120] Although the present disclosure has been described in terms of many embodiments and examples, those skilled in the art who have benefited from this disclosure will appreciate that other embodiments can be designed that do not depart from the scope and spirit of the disclosure as disclosed herein. Although a single embodiment has been discussed, this disclosure encompasses all combinations of all those embodiments.

[0121] Although compositions, methods and processes are described herein in terms of "comprising," "containing," "having," or "including" various components or steps, the compositions and methods may also "consist essentially of" or "consist of" the various components and steps. Unless otherwise specified, the phrases "consist essentially of" and "consist essentially of" do not exclude the presence of other steps, elements, or materials, whether or not specifically mentioned in the specification, as long as such steps, elements, or materials do not affect the basic and novel characteristics of the present disclosure, and further, they do not exclude impurities and variations normally associated with the elements and materials used.

[0122] All numerical values ​​within the detailed description are modified by the indicated value of "about", and take into account experimental errors and deviations that would be expected by a person of ordinary skill in the art.

[0123] Numerous changes, modifications and variations will be apparent to those skilled in the art from the foregoing description without departing from the spirit or scope of the present disclosure, and when numerical lower limits and numerical upper limits are listed herein, ranges from any lower limit to any upper limit are contemplated.

Claims

1. Methods for processing plastic waste, including: thermally cracking at least a plastic waste feed and a cracking feedstock to produce at least a cracking product comprising hydrocarbons, wherein the cracking feedstock has a T10 distillation point of 343° C. or greater; measuring pollutant concentrations; and Regulating plastic waste feed in response to contaminant concentration.

2. The method of claim 1, wherein the pollutant concentration is measured in at least one of: a liquid separated from the pyrolysis product or a gas separated from the pyrolysis product.

3. A method according to claim 1 or claim 2, wherein the contaminant concentration is the concentration of hydrogen chloride and / or one or more organic halides measured in the acidic water produced in the fractionator.

4. A method according to any preceding claim, wherein the pollutant concentration is the concentration of one or more of NOx, carbon monoxide or carbon dioxide in the cracking product, a separated fraction of the cracking product, or sodium accumulation in the coke produced in the thermal cracking step.

5. A method according to any preceding claim, wherein adjusting the plastic waste feed comprises adjusting at least one of: a feed rate of the plastic waste feed to reduce a ratio of the plastic waste feed to the pyrolysis feedstock and / or an amount of one or more plastic waste compositions in the plastic waste feed.

6. A method according to any preceding claim, wherein the plastic waste feed comprises one or more plastics classified by the Association of the Plastics Industry as Plastics Identification Codes 1 to 7, wherein the cracking feed comprises petroleum vacuum residue, and / or wherein the cracking feed has a T10 distillation point of 343°C to 650°C.

7. A method according to any preceding claim, wherein the plastic waste feed is fed to the pyrolysis reactor in the form of a combined feed of plastic waste feed and pyrolysis feed in an amount of about 0.1 wt % to about 25 wt %, and wherein the step of thermal pyrolysis comprises exposing the plastic waste feed and pyrolysis feed to charring conditions.

8. Methods for processing plastic waste, including: physically processing the plastic waste feed to reduce the maximum particle size of the plastic waste feed; combining a plastic waste feedstock with a carrier fluid to form a combined feedstock; Physically processing the combined raw materials to reduce the maximum particle size of solid particles in the combined raw materials; preheating the combined raw materials to cause solid particles in the combined raw materials to melt; and The combined feedstocks are thermally cracked to produce at least a cracked product comprising hydrocarbons.

9. The method of claim 8, wherein the maximum particle size of the plastic waste feed is reduced to about 0.1 mm to about 75 mm during physical processing, and wherein the maximum particle size of the solid particles in the combined feed is reduced to about 0.1 mm to about 1 mm, optionally wherein the plastic waste feed comprises one or more plastics classified by the Association of the Plastics Industry as Plastics Identification Codes 1 to 7.

10. A method according to claim 8 or claim 9, wherein the step of physically processing the combined feedstock to reduce the maximum size of solid particles in the combined feedstock comprises passing the combined feedstock through a ball mill.

11. A method according to any one of claims 8 to 10, wherein the carrier fluid and the plastic waste feed are combined in a heated mixing chamber, and optionally wherein the carrier fluid comprises petroleum vacuum residue.

12. The method of any one of claims 8-11, wherein the plastic waste feed is present in the combined feedstock in an amount of about 0.1 wt% to about 25 wt%, and wherein the step of thermal cracking comprises exposing the combined feedstock to charring conditions.

13. Methods for processing plastic waste, including: Identify target specifications required for plastic waste feedstock; determining a mixture of at least two plastic waste compositions that meets target specifications; mixing at least two plastic waste compositions to form a plastic waste feed; and At least a plastic waste feed and a cracking feedstock are thermally cracked to produce at least a cracking product comprising hydrocarbons, wherein the cracking feedstock has a T10 distillation point of 343° C. or greater.

14. The method of claim 15, wherein the at least two plastic waste compositions comprise a first plastic waste composition that does not meet the target specification and a second plastic waste composition that meets the target specification.

15. A method according to claim 13 or claim 14, wherein the target specification comprises a contaminant concentration, and optionally wherein the target specification comprises an upper limit on halide concentration.

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