FLUID CATALYTIC CRACKING METHOD EMPLOYING A WASTE PLASTIC FEEDSTOCK
A method includes introducing one or more waste plastic feedstocks in neat form to a fluid catalyst cracking unit, and processing the one or more waste plastic feedstocks in neat form in the presence of a catalyst under fluidized catalytic cracking conditions.
The world has seen extremely rapid growth of plastics production. According to Plastics Europe Market Research Group, the world plastics production was 335 million tons in 2016, 348 million tons in 2017, 359 million tons in 2018, and 367 million tons in 2020. According to Mckinsey & Company, the global plastics-waste volume is estimated to be 460 million tons per year by 2030 if the current trajectory continues.
Single use waste plastic has become an increasingly important environmental issue. At the moment, there appear to be few options for recycling waste plastics such as polyethylene and polypropylene waste plastics to value-added chemical and fuel products. Currently, only a small amount of polyethylene and polypropylene is recycled via chemical recycling, where recycled and cleaned polymer pellets are pyrolyzed in a pyrolysis unit to make fuels (naphtha, diesel), stream cracker feed or slack wax. The majority, greater than 80%, is incinerated, land filled or discarded.
SUMMARYIn accordance with an illustrative embodiment, a method comprises:
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- introducing one or more waste plastic feedstocks in neat form to a fluid catalyst cracking unit, and
- processing the one or more waste plastic feedstocks in neat form in the presence of a catalyst under fluidized catalytic cracking conditions.
In accordance with another illustrative embodiment, a method comprises:
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- introducing one or more waste plastic feedstocks in neat form as the only feedstock to a fluid catalyst cracking unit, and
- processing the one or more waste plastic feedstocks in neat form in the presence of a catalyst under fluidized catalytic cracking conditions.
In combination with the accompanying drawing and with reference to the following detailed description, the features, advantages, and other aspects of the implementations of the present disclosure will become more apparent, and several implementations of the present disclosure are illustrated herein by way of example but not limitation. In the accompanying drawing:
Various illustrative embodiments described herein are directed to methods for processing a neat waste plastic feedstock. As mentioned above, waste plastic has become an increasingly important environmental issue. Plastics are inexpensive, easy to mold, and lightweight with many commercial applications. Once the plastic products have outlived their useful lives, they are generally sent to waste disposal such as landfill sites, adding to serious environmental problems, like land, water, and air pollution or recycled by reprocessing the waste into raw material for reuse. In addition, the disposal costs for the post-industrial plastic waste poses an extra burden on processors and manufacturers. Also, there is the consideration that a high demand to produce more virgin resin material places a burden on an already limited and depleting natural resource.
The use of post-industrial and post-consumer polymers (“plastic waste”) through recycling has a variety of benefits over producing virgin resin. Unfortunately, while the economic and environmental demand for products made from recycled plastic exists, the added value created by conventional recycling methods is comparatively low. As a result, large amounts of used plastics can be only partially returned to the economic cycle. Moreover, conventional methods of recycling plastics tend to produce products with lower quality properties. For example, present methods of chemical recycling such as via pyrolysis cannot make a big impact for the plastics industry. The current pyrolysis operation produces poor quality fuel components (naphtha and diesel range products), but the quantity is small enough that these products can be blended into fuel supplies. However, this simple blending cannot continue if we have to recycle very large volumes of waste polyethylene and polypropylene to address the environmental issues. The products produced from the pyrolysis unit have too poor quality to be blended in large amounts (for example, 5 to 20 vol. % blending) in transportation fuels.
The illustrative embodiments described herein overcome these and other drawbacks by providing methods for processing a waste plastic feedstock in neat form resulting in a low carbon source of cracked waste plastic. Accordingly, the methods of the illustrative embodiments described herein avoid the use of petroleum-derived feedstocks as well as recycling of waste plastic and instead make use of waste plastic that would otherwise be landfilled. In non-limiting illustrative embodiments, a method includes introducing one or more waste plastic feedstocks in neat form to a fluid catalyst cracking unit, and processing the one or more waste plastic feedstocks in neat form in the presence of a catalyst under fluidized catalytic cracking conditions.
The term “neat form” as used herein shall be understood to mean a waste plastic feedstock in a solid, semi-melted or in a melted state lacking a solvent or other component, i.e., a feedstock composed of 100% waste plastic. Thus, according to some embodiments of the present disclosure, one or more waste plastic feedstocks may be interacted with the catalyst according to the present disclosure in the absence of solvent or other liquid component. In other embodiments, the waste plastic feedstocks may independently be in a solid, semi-melted or in a melted state when feeding the waste plastic feedstock to a fluid catalytic cracker.
A “fresh catalyst” as used herein denotes a catalyst which has not previously been used in a catalytic process.
A “spent catalyst” as used herein denotes a catalyst that has less activity at the same reaction conditions (e.g., temperature, pressure, inlet flows) than the catalyst had when it was originally exposed to the process. This can be due to a number of reasons, several non-limiting examples of causes of catalyst deactivation are coking or carbonaceous material sorption or accumulation, steam or hydrothermal deactivation, metals (and ash) sorption or accumulation, attrition, morphological changes including changes in pore sizes, cation or anion substitution, and/or chemical or compositional changes.
A “regenerated catalyst” as used herein denotes a catalyst that had become spent, as defined above, and was then subjected to a process that increased its activity to a level greater than it had as a spent catalyst. This may involve, for example, burning the coke off the catalyst, reversing transformations or removing contaminants outlined above as possible causes of reduced activity. The regenerated catalyst typically has an activity that is equal to or less than the fresh catalyst activity.
The term “deactivated catalyst” denotes any catalyst that has less activity at the same reaction conditions (e.g., temperature, pressure, inlet flows) than the catalyst had when it was originally exposed to the process. This can be due to a number of reasons, several non-limiting examples of causes of catalyst deactivation are coking or carbonaceous material sorption or accumulation, metals (and ash) sorption or accumulation, attrition, morphological changes including changes in pore sizes, cation or anion substitution, and/or chemical or compositional changes which may include loss of acidity.
The term “steady state” as used herein is used herein to indicate operating conditions within an FCC reactor unit wherein there exists within the unit a constant amount of catalyst inventory having a constant catalyst activity at a constant rate of feed of a feedstock having a defined composition to obtain a constant conversion rate of products.
The term “catalyst activity” as used herein can be determined on a weight percent basis of conversion of a standard feedstock at standard FCC conditions by the catalyst microactivity test in accordance with ASTM D3907.
The term “upgrade” or “upgrading” generally means to improve quality and/or properties of a hydrocarbon stream and is meant to include physical and/or chemical changes to a hydrocarbon stream. Further, upgrading is intended to encompass removing impurities (e.g., heteroatoms, metals, etc.) from a hydrocarbon stream, converting a portion of the hydrocarbons into shorter chain length hydrocarbons, cleaving single ring or multi-ring aromatic compounds present in a hydrocarbon stream, and/or reducing viscosity of a hydrocarbon stream.
The term “octane number” refers to the percentage of iso-octane in a mixture of iso-octane and n-heptane that would have the same knock resistance as the presently tested fuel, according to ASTM D2699 and D2700. Octane numbers typically range from 0 to 100, with higher values indicating better fuel performance. Octane numbers are unitless.
The term “Research Octane Number” (RON) refers to the octane number obtained by testing at lower engine speed and temperature, typically about 600 rpm, according to ASTM D2699.
The term “Motor Octane Number” (MON) refers to the octane number obtained by testing at higher engine speed and temperature, typically about 900 rpm according to ASTM D2700. Given that engine inefficiency inherently increases as temperature increases, RON is typically higher than MON.
“Anti-knock index” is defined by the arithmetic average of the two octane numbers: (RON+MON)/2.
Applicant reserves the right to proviso out or exclude any individual members of any such group of values or ranges, including any sub-ranges or combinations of sub-ranges within the group, that can be claimed according to a range or in any similar manner, if for any reason Applicant chooses to claim less than the full measure of the disclosure, for example, to account for a reference that Applicant may be unaware of at the time of the filing of the application. Further, Applicant reserves the right to proviso out or exclude any members of a claimed group.
Although any processes and materials similar or equivalent to those described herein can be used in the practice or testing of the illustrative embodiments described herein, the typical processes and materials are herein described.
FeedIn an illustrative embodiment, as may be combined with one or more of the preceding paragraphs, the method involves processing one or more waste plastic feedstocks in neat form. As used herein, a “waste plastic” refers to any post-industrial (or pre-consumer) and post-consumer plastics, such as, for example, one or more polyesters, one or more polyolefins (PO), and/or polyvinylchloride (PVC). As used herein, a “post-consumer plastic” is one that has been used at least once for its intended application for any duration of time regardless of wear, has been sold to an end use customer, or has been discarded into a recycle bin by any person or entity other than a manufacturer or business engaged in the manufacture or sale of the material. A “post-industrial plastic” (or “pre-consumer” plastic) includes all manufactured recyclable organic plastics that are not post-consumer plastics, such as a material that has been created or processed by a manufacturer and has not been used for its intended application, has not been sold to the end use customer, or has been discarded or transferred by a manufacturer or any other entity engaged in the sale or disposal of the material. Examples of post-industrial or pre-consumer plastics include rework, regrind, scrap, trim, out of specification materials, and finished materials transferred from a manufacturer to any downstream customer (e.g., manufacturer to wholesaler to distributor) but not yet used or sold to the end use customer.
The waste plastic may originate from one or more of several sources. In an illustrative embodiment, as may be combined with one or more of the preceding paragraphs, the waste plastic may originate from, for example, plastic bottles, diapers, eyeglass frames, films, packaging materials, carpet (residential, commercial, and/or automotive), textiles (clothing and other fabrics) and combinations thereof. This list is merely illustrative, and any source of waste plastic is contemplated herein.
In an illustrative embodiment, as may be combined with one or more of the preceding paragraphs, a waste plastic includes, for example, a low melting point polyethylene (LMPPE). In an illustrative embodiment, a low melting point polyethylene has a melting point of less than about 100° C. In an illustrative embodiment, a low melting point polyethylene has a melting point of from about 35° C. to about 100° C. In an illustrative embodiment, a low melting point polyethylene has a melting point of from about 40° C. to about 80° C. In an illustrative embodiment, a low melting point polyethylene has a melting point of from about 45° C. to about 60° C. In an illustrative embodiment, a low melting point polyethylene has a melting point of from about 60° C. to about 70° C. The melting point of the low melting point polyethylene can be determined by differential scanning calorimetry (DSC).
In an illustrative embodiment, as may be combined with one or more of the preceding paragraphs, a waste plastic includes, for example, high density polyethylene (HDPE), low density polyethylene (LDPE), high molecular weight polyethylene (HMWPE), low molecular weight polyethylene (LMWPE), polypropylene (PP), polystyrene (PS) and mixed plastics, e.g., a mixture of polyethylene (PE), polypropylene (PP), and polystyrene (PS) or a mixture of LDPE, HDPE and PP.
In an illustrative embodiment, a high density polyethylene has a number average molecular weight of about 100,000 to about 250,000. In an illustrative embodiment, an ultra-high molecular weight polyethylene can have a number average molecular weight of at least about 500,000. In an illustrative embodiment, a high molecular weight polyethylene can have a number average molecular weight of from about 50,000 to about 400,000. In an illustrative embodiment, a low molecular weight polyethylene can have a number average molecular weight of from about 5,000 to about 50,000. In an illustrative embodiment, a high molecular weight polypropylene can have a number average molecular weight of from about 100,000 to about 700,000. In an illustrative embodiment, a high molecular weight polypropylene can have a weight average molecular weight of from about 220,000 to about 700,000. In an illustrative embodiment, a low molecular weight polypropylene can have a number average molecular weight of from about 10,000 to about 100,000.
In an illustrative embodiment, as may be combined with one or more of the preceding paragraphs, the one or more waste plastic feedstocks can comprise at least about 50, or at least about 55, or at least about 60, or at least about 65, or at least about 70, or at least about 75, or at least about 80, or at least about 85, or at least about 95, or at least about 99 weight percent of, for example, polyolefins such as high density polyethylene (HDPE), low density polyethylene (LDPE), ultra-high molecular weight polyethylene, and polypropylene (PP), polyvinyl chloride (PVC), polyvinylidene chloride (PVDC), polyesters such as polyethylene terephthalate (PET), copolyesters and terephthalate copolyesters (e.g., containing residues of TMCD, CHDM, propylene glycol, or NPG monomers), polyamides, poly(methyl methacrylate), polytetrafluoroethylene, acrylonitrile-butadiene-styrene (ABS), polyurethanes, cellulose and derivatives thereof (e.g., cellulose diacetate, cellulose triacetate, or regenerated cellulose), epoxy, phenolic resins, polyacetal, polycarbonates, polyphenylene-based alloys, polystyrene, styrenic compounds, vinyl based compounds, styrene acrylonitrile, polyvinyl acetals (e.g., PVB), urea based polymers, melamine containing polymers, thermosetting, thermoplastic elastomers other than tires, and/or elastomeric plastics and the like and combinations thereof.
Examples of polyesters may include, but are not limited to, those having repeating aromatic or cyclic units such as those containing a repeating terephthalate, isophthalate, or naphthalate units such as polyethylene terephthalate (PET), modified PET, or those containing repeating furanate repeating units. As used herein, “PET” or “polyethylene terephthalate” refers to a homopolymer of polyethylene terephthalate, or to a polyethylene terephthalate modified with one or more acid and/or glycol modifiers and/or containing residues or moieties of other than ethylene glycol and terephthalic acid, such as isophthalic acid, 1,4-cyclohexanedicarboxylic acid, diethylene glycol, 2,2,4,4-tetramethyl-1,3-cyclobutanediol (TMCD), cyclohexanedimethanol (CHDM), propylene glycol, isosorbide, 1,4-butanediol, 1,3-propane diol, and/or neopentyl glycol (NPG).
Also included within the definition of the terms “PET” and “polyethylene terephthalate” are polyesters having repeating terephthalate units (whether or not they contain repeating ethylene glycol-based units) and one or more residues or moieties of a glycol including, for example, TMCD, CHDM, propylene glycol, or NPG, isosorbide, 1,4-butanediol, 1,3-propane diol, and/or diethylene glycol, or combinations thereof. Examples of polymers with repeat terephthalate units can include, but are not limited to, polypropylene terephthalate, polybutylene terephthalate, and copolyesters thereof. Examples of aliphatic polyesters can include, but are not limited to, polylactic acid (PLA), polyglycolic acid, polycaprolactones, and polyethylene adipates. The polymer may comprise mixed aliphatic-aromatic copolyesters including, for example, mixed terephthalates/adipates.
In an illustrative embodiment, as may be combined with one or more of the preceding paragraphs, the waste plastic may comprise terephthalate repeating units in an amount of at least about 1, at least about 5, at least about 10, at least about 15, at least about 20, at least about 25, at least about 30, at least about 35, at least about 40, or at least about 45 and/or not more than about 75, not more than about 70, not more than about 60, or not more than about 65 weight percent, based on the total weight of the plastic in the waste plastic stream, or it may include terephthalate repeat units in an amount in the range of from about 1 to about 75 weight percent, about 5 to about 70 weight percent, or about 25 to about 75 weight percent, based on the total weight of the stream.
Examples of polyolefins may include, but are not limited to, high density polyethylene (HDPE), low density polyethylene (LDPE), high molecular weight polyethylene (HMWPE), low molecular weight polyethylene (LMWPE), polypropylene (PP), atactic polypropylene, isotactic polypropylene, syndiotactic polypropylene, crosslinked polyethylene, amorphous polyolefins, and the copolymers of any one of the aforementioned polyolefins. In an illustrative embodiment, as may be combined with one or more of the preceding paragraphs, the waste plastic may include polymers including linear low-density polyethylene (LLDPE), polymethylpentene, polybutene-1, and copolymers thereof. In an embodiment, the waste plastic may comprise flashspun high density polyethylene.
In an illustrative embodiment, as may be combined with one or more of the preceding paragraphs, the one or more waste plastic feedstocks can include, for example, thermosetting, thermoplastic, and/or elastomeric plastics. For example, the number average molecular weight of the thermosetting, thermoplastic, and/or elastomeric plastics can be at least about 300, or at least about 500, or at least about 1000, or at least about 5,000, or at least about 10,000, or at least about 20,000, or at least about 30,000, or at least about 50,000 or at least about 70,000 or at least about 90,000 or at least about 100,000, or at least about 130,000 and up to about 300,000, or up to about 200,000, or up to about 150,000, or up to about 100,000, or up to about 90,000, or up to about 70,000, or up to about 50,000, or up to about 30,000, or up to about 20,000, or up to about 10,000, or up to about 5,000, or up to about 1,000.
Examples of cellulose materials include, but are not limited to, cellulose acetate, cellulose diacetate, cellulose triacetate, cellulose acetate propionate, cellulose acetate butyrate, as well as regenerated cellulose such as viscose. Additionally, the cellulose materials can include cellulose derivatives having an acyl degree of substitution of less than about 3, not more than about 2.9, not more than about 2.8, not more than about 2.7, or not more than about 2.6 and/or at least about 1.7, at least about 1.8, or at least about 1.9.
In an illustrative embodiment, as may be combined with one or more of the preceding paragraphs, a waste plastic may include a mixed plastic waste (“MPW”) containing any combination of the foregoing waste plastics.
In an illustrative embodiment, as may be combined with one or more of the preceding paragraphs, the one or more waste plastic feedstocks can be any organic synthetic polymer that is solid at 25° C. at 1 atm. For example, in an illustrative embodiment, the organic synthetic polymers that are solid at 25° C. and 1 atmosphere of pressure may have a number average molecular weight (Mn) of at least about 300, or at least about 500, or at least about 1000, or at least about 5,000, or at least about 10,000, or at least about 20,000, or at least about 30,000, or at least about 50,000 or at least about 70,000 or at least about 90,000 or at least about 100,000 or at least about 130,000, or at least about 150,000 Daltons. The weight average molecular weight (Mw) of the polymers can be at least about 300, or at least about 500, or at least about 1000, or at least about 5,000, or at least about 10,000, or at least about 20,000, or at least about 30,000 or at least about 50,000, or at least about 70,000, or at least about 90,000, or at least about 100,000, or at least about 130,000, or at least about 150,000, or at least about 300,000 or at least about 400,000 Daltons. In an embodiment or in combination with any embodiment mentioned herein, the polymers have an average molecular weight, Mw, in the range of about 5,000 to about 150,000. In an embodiment or in combination with any embodiment mentioned herein, the polymers have an average molecular weight, Mw, in the range of greater than about 150,000 to about 400,000.
In an illustrative embodiment, as may be combined with one or more of the preceding paragraphs, the form of the one or more waste plastic feedstocks can include any of the forms of articles, products, materials, or portions thereof. For example, a portion of an article can take the form of sheets, extruded shapes, moldings, films, carpet, laminates, foam pieces, chips, flakes, particles, agglomerates, briquettes, powder, shredded pieces, long strips, randomly shaped pieces having a wide variety of shapes, or any other form other than the original form of the article and adapted to feed to the FCC unit discussed hereinbelow.
In an illustrative embodiment, as may be combined with one or more of the preceding paragraphs, the one or more waste plastic feedstocks can be in the form of solid particles, such as chips, flakes, or a powder. In another embodiment, the one or more waste plastic feedstocks may comprise particulates such as, for example, shredded plastic particles, chopped plastic particles, or plastic pellets.
In an illustrative embodiment, as may be combined with one or more of the preceding paragraphs, the one or more waste plastic feedstocks can include at least about 50, or at least about 55, or at least about 60, or at least about 65, or at least about 70, or at least about 75, or at least about 80, or at least about 85, or at least about 95, or at least about 99 weight percent of recycled textiles and/or recycled carpet, such as synthetic fibers, rovings, yarns, nonwoven webs, cloth, fabrics and products made from or containing any of the aforementioned plastics. The textiles can include woven, knitted, knotted, stitched, tufted, felted, embroidered, laced, crocheted, braided, or nonwoven webs and materials. The textiles can include fabrics, fibers separated from a textile or other product containing fibers, scrap or off spec fibers or yarns or fabrics, or any other source of loose fibers and yarns. Furthermore, the textiles may also include staple fibers, continuous fibers, threads, tow bands, twisted and/or spun yarns, grey fabrics made from yarns, finished fabrics produced by wet processing gray fabrics, garments made from the finished fabrics, or any other fabrics. Textiles include apparels, interior furnishings, and industrial types of textiles. Textiles also include post-industrial textiles or post-consumer textiles or both.
Examples of textiles in the apparel category (things humans wear or made for the body) include, but are not limited to, sports coats, suits, trousers and casual or work pants, shirts, socks, sportswear, dresses, intimate apparel, outerwear such as rain jackets, cold temperature jackets and coats, sweaters, protective clothing, uniforms, and accessories such as scarves, hats, and gloves. Examples of textiles in the interior furnishing category include furniture upholstery and slipcovers, carpets and rugs, curtains, bedding such as sheets, pillow covers, duvets, comforters, mattress covers; linens, tablecloths, towels, washcloths, and blankets. Examples of industrial textiles include transportation (auto, airplanes, trains, buses) seats, floor mats, trunk liners, and headliners; outdoor furniture and cushions, tents, backpacks, luggage, ropes, conveyor belts, calendar roll felts, polishing cloths, rags, soil erosion fabrics and geotextiles, agricultural mats and screens, personal protective equipment, bullet proof vests, medical bandages, sutures, tapes, and the like.
The nonwoven webs that are classified as textiles do not include the category of wet laid nonwoven webs and articles made therefrom. While a variety of articles having the same function can be made from a dry or wet laid process, the article made from the dry laid nonwoven web is classified as a textile. Examples of suitable articles that may be formed from dry laid nonwoven webs as described herein can include those for personal, consumer, industrial, food service, medical, and other types of end uses. Specific examples can include, but are not limited to, baby wipes, flushable wipes, disposable diapers, training pants, feminine hygiene products such as sanitary napkins and tampons, adult incontinence pads, underwear, or briefs, and pet training pads. Other examples include a variety of different dry or wet wipes, including those for consumer (such as personal care or household) and industrial (such as food service, health care, or specialty) use.
Nonwoven webs can also be used as padding for pillows, mattresses, and upholstery, batting for quilts and comforters. In the medical and industrial fields, nonwoven webs of the present invention may be used for medical and industrial face masks, protective clothing, caps, and shoe covers, disposable sheets, surgical gowns, drapes, bandages, and medical dressings. Additionally, nonwoven webs as described herein may be used for environmental fabrics such as geotextiles and tarps, oil and chemical absorbent pads, as well as building materials such as acoustic or thermal insulation, tents, lumber and soil covers and sheeting. Nonwoven webs may also be used for other consumer end use applications, such as for, carpet backing, packaging for consumer, industrial, and agricultural goods, thermal or acoustic insulation, and in various types of apparel. The dry laid nonwoven webs as described herein may also be used for a variety of filtration applications, including transportation (e.g., automotive or aeronautical), commercial, residential, industrial, or other specialty applications. Examples can include filter elements for consumer or industrial air or liquid filters (e.g., gasoline, oil, water), including nanofiber webs used for microfiltration, as well as end uses like tea bags, coffee filters, and dryer sheets. Further, nonwoven webs as described herein may be used to form a variety of components for use in automobiles, including, but not limited to, brake pads, trunk liners, carpet tufting, and under padding.
The textiles can include a single type or multiple types of natural fibers and/or a single type or multiple types of synthetic fibers. Examples of textile fiber combinations include all natural, all synthetic, two or more types of natural fibers, two or more types of synthetic fibers, one type of natural fiber and one type of synthetic fiber, one type of natural fibers and two or more types of synthetic fibers, two or more types of natural fibers and one type of synthetic fibers, and two or more types of natural fibers and two or more types of synthetic fibers.
Natural fibers include those that are plant derived or animal derived. Natural fibers can be cellulosics, hemicellulosics, and lignins. Examples of plant derived natural fibers include hardwood pulp, softwood pulp, and wood flour; and other plant fibers including those in wheat straw, rice straw, abaca, coir, cotton, flax, hemp, jute, bagasse, kapok, papyrus, ramie, rattan, vine, kenaf, abaca, henequen, sisal, soy, cereal straw, bamboo, reeds, esparto grass, bagasse, Sabai grass, milkweed floss fibers, pineapple leaf fibers, switch grass, lignin-containing plants, and the like. Examples of animal derived fibers include wool, silk, mohair, cashmere, goat hair, horsehair, avian fibers, camel hair, angora wool, and alpaca wool.
Synthetic fibers are those fibers that are, at least in part, synthesized or derivatized through chemical reactions, or regenerated, and include, but are not limited to, rayon, viscose, mercerized fibers or other types of regenerated cellulose (conversion of natural cellulose to a soluble cellulosic derivative and subsequent regeneration) such as lyocell (also known as TENCEL™), Cupro, Modal, acetates such as polyvinylacetate, polyamides including nylon, polyesters such as PET, olefinic polymers such as polypropylene and polyethylene, polycarbonates, poly sulfates, polysulfones, polyethers such as polyether-urea known as Spandex or elastane, polyacrylates, acrylonitrile copolymers, polyvinylchloride (PVC), polylactic acid, polyglycolic acid, sulfopolyester fibers, and combinations thereof.
The textiles can be in any of the forms mentioned above, such as size reduction via chopping, shredding, harrowing, confrication, pulverizing, or cutting a feedstock of textiles to make size reduced textiles. The textiles can also be densified. Examples of processes that densify include those that agglomerate the textiles through heat generated by frictional forces or particles made by extrusion or other external heat applied to the textile to soften or melt a portion or all of the textile.
The one or more waste plastic feedstocks can be obtained from a plastic source including, by way of example, a hopper, storage bin, railcar, over-the-road trailer, or any other device that may hold or store waste plastics. In an embodiment, the plastic source can include a municipal reclaimer facility, an industrial facility, a recycling facility, a commercial facility, a manufacturing facility, or combinations thereof.
The waste plastics can be washed to remove any metal contaminants such as sodium, calcium, magnesium, aluminum, and non-metal contaminants coming from other waste sources. Non-metal contaminants include contaminants coming from the Periodic Table Group 14, such as silica, contaminants from Group 15, such as phosphorus and nitrogen compounds, contaminants from Group 16, such as sulfur compounds, and halide contaminants from Group 17, such as fluoride, chloride, and iodide. The residual metals, non-metal contaminants, and halides need to be removed to less than about 50 parts per million (ppm), or less than about 30 ppm or less than about 5 ppm.
CatalystThe cracking catalyst for the FCC unit is circulated through the unit in a continuous manner between catalytic cracking reaction and regeneration while maintaining the cracking catalyst in the reactor. In conventional processes, a catalyst injection system maintains a continuous or semi-continuous addition of fresh catalyst to the inventory circulating between the regenerator and the reactor. In the present process, discarded or spent catalyst from a high activity FCC process is employed in the place of fresh catalyst. Spent catalyst is usually considered industrial waste and some refineries pay to dispose of this material.
The spent catalyst may be added directly to a regeneration zone of the FCC unit or at any other suitable point.
In an illustrative embodiment, as may be combined with one or more of the preceding paragraphs, the cracking catalyst that can be used herein can be any known cracking catalyst for use in a fluidized catalytic cracking unit. Suitable cracking catalysts include, for example, FCC catalysts which generally comprise a zeolite. In an illustrative embodiment, a cracking catalyst can comprise either a large-pore zeolite or a mixture of at least one large-pore zeolite catalyst and at least one medium-pore molecular sieve catalyst. Suitable large-pore zeolites include, for example, a Y zeolite with or without rare earth metal, a HY zeolite with or without a rare earth metal, an ultra-stable Y zeolite with or without a rare earth metal, a Beta zeolite with or without a rare earth metal, and combination thereof. Suitable medium-pore zeolites include, for example, ZSM-5, ZSM-11, ZSM-12, ZSM-23, ZSM-35, ZSM-48, and other similar materials.
In an illustrative embodiment, as may be combined with one or more of the preceding paragraphs, a suitable cracking catalyst for use herein is an equilibrium catalyst (ECAT catalyst) such as, for example, typical ultra-stable Y based FCC catalysts such as Y based zeolite catalysts. In non-limiting illustrative embodiments, a suitable cracking catalyst for use herein is a circulating inventory of an equilibrium catalyst composition. In other non-limiting illustrative embodiments, a suitable cracking catalyst for use herein is a ZSM-5 catalyst.
In an illustrative embodiment, the cracking catalyst can comprise, on a dry basis, about 10 to about 50 wt. % by weight of a zeolite, about 5 to about 90 wt. % by weight of an amorphous inorganic oxide and 0 to about 70 wt. % by weight of a filler, based on the total weight of the catalytic cracking catalyst. Suitable amorphous inorganic oxides include, for example, silica, alumina, titania, zirconia, and magnesium oxide. Suitable fillers include, for example, clays such as kaolin and halloysite.
In an illustrative embodiment, a blend of large-pore and medium-pore zeolites may be used. For example, the weight ratio of the large-pore zeolite to the medium-pore size zeolite in the cracking catalyst can be in a range of about 100:0 to about 0:100.
The spent catalyst may be a metal poisoned spent catalyst. The metal can be an alkali metal, an alkaline earth metal, a transition metal, or a combination thereof. The alkali metal can be sodium (Na), potassium (K), or a combination thereof. The alkaline earth metal can be magnesium (Mg), calcium (Ca), or a combination thereof. The transition metal can be vanadium (V), nickel (Ni), iron (Fe), or a combination thereof. In some aspects, the metal poisoned spent catalyst comprises one or more metals selected from Na, K, Mg, Ca, V, Ni, and Fe. In other aspects, the metal doped spent catalyst comprises one or more metals selected from Na, K, Mg, and Ca. The metal poisoned spent catalyst can have a metal concentration of at least about 500 ppm (e.g., about 500 to about 35000 ppm, about 500 to about 20000 ppm, about 750 to about 20000 ppm, or about 500 to about 3000 ppm).
In an illustrative embodiment, as may be combined with one or more of the preceding paragraphs, the cracking catalyst can include at least about 80 wt. % (e.g., at least about 85 wt. %, at least about 90 wt. %, at least about 95 wt. %, or at least about 100 wt. %) of a phosphorus-containing ZSM-5 light olefins additive. Any conventional phosphorus-containing ZSM-5 light olefin additive typically used in an FCC process for light olefin production may be employed herein.
In an illustrative embodiment, the phosphorus-containing ZSM-5 light olefin additive may include, for example (a) about 25 to about 50 wt. % (e.g., about 40 to about 50 wt. %) of ZSM-5 zeolite, (b) about 3 to about 15 wt. % (e.g., about 5 to about 10 wt. %) of phosphorus, measured as P2O5, (c) about 5 to about 40 wt. % (e.g., about 10 to about 20 wt. %) of a clay, and (d) about 5 to about 20 wt. % (e.g., about 10 to about 20 wt. %) of a binder.
A suitable clay includes, for example, kaolin, halloysite, bentonite, and any combination thereof. In an embodiment, the clay is kaolin.
A suitable binder includes, for example, a silica sol, an alumina sol, pseudoboehmite alumina, bayerite alumina, gamma-alumina, and any combination thereof.
Representative examples of suitable P/ZSM-5 light olefin additives include those commercially available from such sources as Grace (e.g., OlefinsMax®, OlefinsUltra®, OlefinsUltra® HZ, OlefinsUltra® MZ and OlefinsUltra® XZ) and from Johnson Matthey (e.g., INTERCAT™, PENTACAT™ HP, PROPYL MAX™, SUPER Z™, SUPER Z EXCEL, SUPER Z EXCEED, ISOCAT™, and OCTAMAX™).
In an embodiment, the cracking catalyst may further include, for example, a large-pore molecular sieve component in addition to the phosphorus-containing ZSM-5 light olefin additive. The large-pore molecule sieve component may include, for example, a *BEA framework type zeolite (e.g., Beta zeolite) and/or a FAU framework type zeolite (e.g., Y zeolite). When used, the large-pore molecular sieve component is typically present in an amount of no more than about 20 wt. % (e.g., about 0.1 to about 20 wt. %, or about 1 to about 15 wt. %), based on the total weight of the cracking catalyst. Optionally, the additional molecular sieve component may further comprise matrix, binder and/or clay.
The cracking catalyst may be in the form of shaped microparticles, such as microspheres. The term “microparticles” as used herein refers to particles having a size of from about 0.1 microns to about 100 microns. The size of a microparticle refers to the maximum length of a particle from one side to another, measured along the longest distance of the microparticle.
The cracking catalyst may be deactivated by contact with steam prior to use in a reactor to convert the feedstock. The purpose of steam treatment is to accelerate the hydrothermal aging which occurs in an operational FCC regenerator to obtain an equilibrium catalyst. Steam treatment may lead to the removal of aluminum from the framework leading to a decrease in the number of sites where framework hydrolysis can occur under hydrothermal and thermal conditions. This removal of aluminum results in an increased thermal and hydrothermal stability in dealuminated zeolites.
In an illustrative embodiment, as may be combined with one or more of the preceding paragraphs, the steam treatment comprises steaming the catalyst under a steam and inert gas atmosphere at a temperature greater than 500° C., e.g., a temperate ranging from about 700° C. to about 800° C., or from about 720° C. to about 740° C. The catalyst can be steam treated with 100% steam, or the steam treating step can comprise a combination of steam and inert gas. Suitable inert gases include, for example, any inert gas that does not react with the catalyst, including nitrogen and argon, or a mixture of inert gases. Steam treatment can be performed for a time period ranging from about 1 minute to about 24 hours, or from about 5 minutes to about 12 hours, or from about 10 minutes to about 8 hours.
The cracking catalyst of the present disclosure may contain metal contaminants. The minimum amount of metal contaminants accumulated on the cracking catalyst can be about 1000 ppm, or about 2000 ppm, or about 3000 ppm, or about 4000 ppm, or about 5000 ppm; or alternatively, the maximum amount of metal contaminants accumulated on the cracking catalyst can be about 50,000 ppm, or about 45,000 ppm, or about 40,000 ppm, or about 35,000 ppm, or about 30,000 ppm, or about 25,000 ppm, or about 20,000 ppm, or about 15,000 ppm, or about 10,000 ppm. Generally, the amount of metal contaminants can be in a range from any minimum value disclosed herein to any maximum value disclosed herein. Representative contaminant metals include sodium, potassium, magnesium, calcium, vanadium, nickel, iron, and mixtures thereof.
The cracking catalyst may contain carbon-containing deposits. The carbon-containing deposits on the cracking catalyst are sometimes also referred to as coke. The minimum amount of coke on the cracking catalyst can be about 0.1 wt. %, or about 0.5 wt. %, or about 1.0 wt. %, or about 1.5 wt. %, or about 2.0 wt. %, or about 2.5 wt. %; or alternatively, the maximum amount of coke on the cracking catalyst can be about 5.0 wt. %, or about 4.5 wt. %, or about 4.0 wt. %, or about 3.5 wt. %, or about 3.0 wt. %. Generally, the amount of coke can be in a range from any minimum value disclosed herein to any maximum value disclosed herein.
FCC ProcessThe catalytic process can be either fixed bed, moving bed or fluidized bed and the feedstock flow may be either concurrent or countercurrent to the catalyst flow. The present process is particularly applicable to fluid catalytic cracking (FCC) processes.
The process of the present disclosure is particularly applicable to fluid catalytic cracking (FCC), in which the cracking catalyst is typically a fine powder. This powder is generally suspended in the feed and propelled upward in a reaction zone. The feedstock is admixed with the cracking catalyst to provide a fluidized suspension and cracked in an elongated reactor, or riser, at elevated temperatures to provide a mixture of lighter hydrocarbon products. The gaseous reaction products and spent catalyst are discharged from the riser into a separator (e.g., a cyclone unit) located within the upper section of an enclosed stripping vessel, or stripper, with the reaction products being conveyed to a product recovery zone and the spent catalyst entering a dense catalyst bed within the lower section of the stripper. In order to remove entrained hydrocarbons from the spent catalyst prior to conveying the latter to a catalyst regenerator unit, an inert stripping gas (e.g., steam) is passed through the catalyst bed where it desorbs such hydrocarbons conveying them to the product recovery zone. The fluidizable catalyst is continuously circulated between the riser and the regenerator and serves to transfer heat from the latter to the former thereby supplying the thermal needs of the cracking reaction which is endothermic.
It is normally preferred to carry out the catalytic cracking in a unit dedicated to waste plastic feed cracking (i.e., with a feed comprised entirely of waste plastic feedstock). In such cases, the product from the cracking unit is a product produced in industrially relevant amounts by the process as described herein. By “industrially relevant amounts” is meant amounts that enter the consumer market rather than laboratory scale amounts. In one example, industrially relevant amounts are produced continuously at greater than 100 liters of renewable product per day for a time period of at least one month.
In illustrative embodiments, the process may include introducing, injecting, feeding, or co-feeding the one or more waste plastic feedstocks via a mixing zone, a nozzle, a retro-fitted port, a retro-fitted nozzle, a velocity steam line, or a live-tap. In other illustrative embodiments, the processing may comprise co-injecting the one or more waste plastic feedstocks, such as co-feeding, independently or separately introducing, injecting, feeding, or co-feeding the waste plastic feedstock into a fluidized catalytic cracking unit. For example, the one or more waste plastic feedstocks may be provided, introduced, injected, fed, or co-fed proximate to each other into the reactor, reaction zone, reaction riser, stripper or riser quench of a fluidized catalytic cracking unit.
In an illustrative embodiment, as may be combined with one or more of the preceding paragraphs, the one or more waste plastic feedstocks in neat form can be introduced into the fluidized catalytic cracking unit in its common state, and in other embodiments it may be introduced into the mold in a semi-melted state or a melted state. For example, in an illustrative embodiment, when the one or more waste plastic feedstocks in neat form are introduced into the fluidized catalytic cracking unit in its common state, i.e., in solid form, it may be necessary to increase the pressure of the feedstock in order to flow the one or more waste plastic feedstocks through the fluidized catalytic cracking unit to subject it to cracking as discussed below. In an illustrative embodiment, a pump (not shown) can be employed to increase the pressure of the one or more waste plastic feedstocks in neat form to generate a pressurized one or more waste plastic feedstocks in neat form for use in the process and system of the illustrative embodiments described herein. For example, the one or more waste plastic feedstocks in neat form can be pumped in a pump to a pressure of about 2 bar to about 8 bar.
In another illustrative embodiment, the one or more waste plastic feedstocks in neat form can be exposed to heat to change the one or more waste plastic feedstocks in neat form from its common state to one of a semi-melted or melted state to allow the one or more waste plastic feedstocks in neat form to flow more easily through the process and system of the illustrative embodiments described herein. For example, the one or more waste plastic feedstocks in neat form can be introduced into a primary melting extruder (not shown) where it is melted to produce a waste plastic feedstock melt. In an illustrative embodiment, for feeding to a fluidized catalytic cracking unit, the waste plastic feedstock is heated above the melting point of the plastic to produce a homogeneous liquid of plastic. In other illustrative embodiments, the temperature used can be one that will decompose PVC without substantially decomposing any of the other plastics. In other embodiments, by keeping the temperature at about 550° to about 700° F., only polyvinyl chloride decomposes to HCl and hydrocarbons. In addition, at this temperature range, polyethylene and polypropylene stay in the melted state but are not decomposed. By minimizing the decomposition of polyethylene and polypropylene, the amounts of olefins and dienes in the blend are limited, and this will minimize formation of organic chlorides which can be made by reaction of olefins and HCl. A stripping gas such as nitrogen, hydrogen, steam, or offgas from a conversion unit may be added to facilitate purging of HCl offgas from the decomposition of PVC or organic chlorides in the blend. Hydrogen may be a preferred stripping gas as it facilitates HCl formation and minimizes diene formation.
What is meant by heating the waste plastic feedstock to a temperature above the melting point of the waste plastic is clear when a single plastic is used. However, if the waste plastic comprises more than one waste plastic, then the melting point of the plastic with the highest melting point is exceeded. Thus, the melting points of all plastics must be exceeded. Similarly, if the waste plastic is cooled below the melting point of the plastic, the temperature must be cooled below the melting points of all plastics comprising the blend.
In one or more embodiments, the primary melting extruder may comprise any equipment capable of melting and conveying a waste plastic feedstock to the fluidized catalytic cracking unit apparent to one of ordinary skill in the art. Suitable extruders include, for example, twin-screw extruders or single-screw extruders. In some embodiments, a primary melting extruder vent can be present for the removal of any volatile components from the primary melting extruder. A primary melting extruder inlet can be present where it conveys the waste plastic feedstock to the primary melting extruder, and an outlet to convey the waste plastic feedstock to the fluidized catalytic cracking unit. The extruder can either one of melt the waste plastic feedstock to a semi-melted state so that it is capable of flowing through the process and system of the illustrative embodiments described herein, or melt the waste plastic feedstock to a melted state.
In illustrative embodiments, the fluid catalytic cracking process in which the one or more waste plastic feedstocks in neat form will be cracked to lighter hydrocarbon products takes place by contact of the feed in a cyclic catalyst recirculation cracking process with a circulating fluidizable catalytic cracking catalyst inventory as discussed above consisting of particles having a size ranging from about 20 to about 100 microns. In an illustrative embodiment, representative examples of the steps in the cyclic process include: (1) the feed is catalytically cracked in a catalytic cracking zone, normally a riser cracking zone, operating at catalytic cracking conditions by contacting the feed with a source of hot, regenerated cracking catalyst to produce an effluent comprising cracked products and spent catalyst containing coke and strippable hydrocarbons; (2) the effluent is discharged and separated, normally in one or more cyclones, into a vapor phase rich in cracked product and a solids rich phase comprising the spent catalyst; (3) the vapor phase is removed as product and fractionated in the FCC main column and its associated side columns to form liquid cracking products including gasoline; and (4) the spent catalyst is stripped, usually with steam, to remove occluded hydrocarbons from the catalyst, after which the stripped catalyst is oxidatively regenerated to produce hot, regenerated catalyst which is then recycled to the cracking zone for cracking further quantities of feed.
Suitable cracking conditions include, for example, a reaction temperature of about 425° C. to about 650° C. (e.g., about 450° C. to about 600° C., or about 500° C. to about 575° C.), a catalyst regeneration temperature of about 600° C. to about 800° C.; a hydrocarbon partial pressure of about a pressure of from about 100 kPa to about 1100 kPa (e.g., about 200 kPa to about 400 kPa); a catalyst-to-oil mass ratio of from about 3 to about 12 (e.g., about 4 to about 11, or about 5 to about 10); and a catalyst contact time of from about 0.1 to about 15 seconds (e.g., about 0.2 to about 10 seconds). Suitable catalyst regeneration temperatures include a temperature ranging from about 600° C. to about 800° C. at a pressure ranging from about 100 kPa to about 1100 kPa.
The term “hydrocarbon partial pressure” is used herein to indicate the overall hydrocarbon partial pressure in the riser reactor. The term “catalyst-to-oil ratio’ refers to the ratio of the catalyst circulation amount (e.g., ton/h) and the feedstock supply rate (e.g., ton/h). The term “catalyst contact time” is used herein to indicate the time from the point of contact between the feedstock and the catalyst at the catalyst inlet of the riser reactor until separation of the reaction products and the catalyst at the stripper outlet.
ProductsAfter the feed comprising the waste plastic feedstock has been subjected to fluidized catalytic cracking conditions, the effluent from the reaction system having a variety of cracked hydrocarbon products may be separated into two or more constituent streams by conventional means. Constituent streams may include a fuel gas stream, an ethylene stream, a propylene stream, a butylene stream, an LPG stream, a naphtha stream, an olefin stream, a diesel stream, a gasoline stream, a heavy cycle oil (HCO) stream, a light cycle oil stream, an aviation fuel stream, a cat unit bottoms (slurry/decant oil) stream, and other hydrocarbon streams.
In some aspects, a constituent stream may be further processed. For example, an olefinic constituent stream may be sent to an alkylation unit for further processing. In addition, olefins from the constituent streams may be further separated and recovered for use in renewable plastics and petrochemicals.
Hydrocarbon fuel products may be sold or further processed. Examples of further processing include blending, hydroprocessing, or alkylating at least a portion of the hydrocarbon fuel product. Hydrocarbon fuel products may be used as a blend stock and combined with one or more petroleum fuel products and/or renewable fuels. Petroleum-based streams include gasoline, diesel, aviation fuel, or other hydrocarbon streams obtained by refining of petroleum. Examples of renewable fuels include ethanol, propanol, and butanol.
In some aspects, the product stream can comprise a gasoline fraction in an amount ranging from about 30 to about 60 wt. % (e.g., about 40 to about 50 wt. %), based on the total product stream composition, as measured by ASTM D2887.
The following non-limiting examples are illustrative of the present disclosure.
In the following examples, pure low melting point polyethylene (LMPPE) was thermally cracked over an inert aluminosilicate material acting as a heat carrier, and catalytically cracked over a ZSM-5 based catalyst. Further, the ZSM-5 catalyst was deactivated by metal poisoning and steaming to demonstrate how robust it is for this process. The LMPPE had a melting point of 47° C., as determined by differential scanning calorimetry (DSC).
Catalyst DeactivationA ZSM-5 based catalyst was deactivated by metal impregnation as well as steaming.
SteamingPrior to use, the ZSM-5 additive was subjected to 50% steam treatment at 800° C. for 24 hours.
In some examples, prior to steaming, the catalysts were impregnated with metals known to poison catalysts. The metals are equal parts by weight Ca+Mg+Na+Zn, to give a final product with 1 or 2 wt. % metals, and they were added as nitrate salts using incipient wetness impregnation, which is well known in the field. After impregnation the catalysts were dried in air overnight and then calcined at 594° C. for one hour. Following calcination, the materials were steamed.
Examples 1-6 TestingCatalytic cracking experiments were carried out using an Advanced Cracking Evaluation (ACE) Model C unit fabricated by Kayser Technology. The reactor employed in the ACE unit was a fixed fluidized reactor with 1.6 cm ID. Nitrogen was used as fluidization gas and introduced from both bottom and top. The top fluidization gas was used to carry the feed injected from a calibrated syringe feed pump via a three-way valve. The catalytic cracking of the feed was carried out at atmospheric pressure and 975° F. For each experiment, a constant amount of feed was injected at the rate of 1.2 g/min for 75 seconds. The catalyst-to-oil mass ratio was maintained at 6 for each catalyst tested. After 75 seconds of feed injection, the catalyst was stripped off by nitrogen for a period of 525 seconds.
During the catalytic cracking and stripping process, the liquid product was collected in a sample vial attached to a glass receiver, which was located at the end of the reactor exit and was maintained at −15° C. The gaseous products were collected in a closed stainless-steel vessel (12.6 L) prefilled with N2 at 1 atm. Gaseous products were mixed by an electrical agitator rotating at 60 rpm as soon as feed injection was completed. After stripping, the gaseous products were further mixed for 10 minutes to ensure homogeneity. The final gaseous products were then analyzed using a refinery gas analyzer (RGA).
After the completion of stripping process, in-situ catalyst regeneration was carried out in the presence of air at 1300° F. The regeneration flue gas passed through a catalytic converter packed with CuO pellets (LECO Inc.) to oxidize CO to CO2. The regeneration flue gas was then analyzed by an online infrared (IR) analyzer located downstream from the catalytic converter. Coke deposited during cracking process was calculated from the CO2 concentrations measured by the IR analyzer.
As mentioned above, gaseous products, mainly C1 to C7 hydrocarbons, were resolved in an RGA. The RGA is a customized Agilent 7890B gas chromatograph (GC) equipped with three detectors, a flame ionization detector for hydrocarbons and two thermal conductivity detectors for nitrogen and hydrogen. Gas products were grouped into dry gas (C2-hydrocarbons and H2) and liquefied petroleum gas (C3 and C4 hydrocarbons). Liquid products were weighed and analyzed in a simulated distillation GC (Agilent 6890) using ASTM D2887. The liquid products were cut into gasoline (C5 to 430° F.), light cycle oil (430° F.+ to 650° F.) and heavy cycle oil (650° F.+). Gasoline (C5+ hydrocarbons) in the gaseous products were combined with gasoline in the liquid products as total gasoline. Light ends in the liquid products (C5.) were also subtracted from liquid products and added back to C3 and C4 species using some empirical distributions. Material balances were between 98% and 101% for most experiments.
Detailed hydrocarbon analysis (DHA) using Agilent 6890A (Separation Systems Inc.) were also performed on the gasoline portion of liquid products for PONA (paraffins, olefins, naphthenes, and aromatics) and octanes (RON and MON). DHA analysis on the gasoline portion in gaseous products was not performed. Therefore, the adjustment to total gasoline properties was not performed. Nevertheless, the DHA results still provided valuable information to evaluating catalytic cracking product properties. The results of the experiments are set forth below in Table 1.
According to an aspect of the present disclosure, a method comprises:
-
- introducing one or more waste plastic feedstocks in neat form to a fluid catalyst cracking unit, and
- processing the one or more waste plastic feedstocks in neat form in the presence of a catalyst under fluidized catalytic cracking conditions.
In one or more additional illustrative embodiments, as may be combined with the preceding paragraphs, the one or more waste plastic feedstocks comprise one or more polyesters, one or more polyolefins and combinations thereof.
In one or more additional illustrative embodiments, as may be combined with the preceding paragraphs, the one or more waste plastic feedstocks comprise a low melting point polyethylene.
In one or more additional illustrative embodiments, as may be combined with the preceding paragraphs, the one or more waste plastic feedstocks comprise a low melting point polyethylene having a melting point of from about 35° C. to about 100° C.
In one or more additional illustrative embodiments, as may be combined with the preceding paragraphs, the one or more waste plastic feedstocks comprise one or more of a high density polyethylene, a low density polyethylene, a high molecular weight polyethylene, a low molecular weight polyethylene, polypropylene, polystyrene and combinations thereof.
In one or more additional illustrative embodiments, as may be combined with the preceding paragraphs, where introducing the one or more waste plastic feedstocks in neat form to a fluid catalyst cracking unit comprises introducing the one or more waste plastic feedstocks in neat form in a solid state to the fluid catalyst cracking unit.
In one or more additional illustrative embodiments, as may be combined with the preceding paragraphs, where introducing the one or more waste plastic feedstocks in neat form to a fluid catalyst cracking unit comprises introducing the one or more waste plastic feedstocks in neat form in a semi-melted state to the fluid catalyst cracking unit.
In one or more additional illustrative embodiments, as may be combined with the preceding paragraphs, where introducing the one or more waste plastic feedstocks in neat form to a fluid catalyst cracking unit comprises introducing the one or more waste plastic feedstocks in neat form in a melted state to the fluid catalyst cracking unit.
In one or more additional illustrative embodiments, as may be combined with the preceding paragraphs, where the catalyst is a fluid catalytic cracking catalyst.
In one or more additional illustrative embodiments, as may be combined with the preceding paragraphs, where the catalyst is a deactivated fluid catalytic cracking catalyst.
In one or more additional illustrative embodiments, as may be combined with the preceding paragraphs, where the catalyst is a deactivated fluid catalytic cracking catalyst discharged from a fluid catalytic cracking process, the catalyst having deactivating deposits accumulated thereon.
In one or more additional illustrative embodiments, as may be combined with the preceding paragraphs, where the deactivating deposits comprise at least one metal contaminant selected from the group consisting of sodium, potassium, magnesium, calcium, vanadium, nickel, iron, zinc and a mixture thereof.
In one or more additional illustrative embodiments, as may be combined with the preceding paragraphs, where the catalyst has been subjected to a steam treatment.
In one or more additional illustrative embodiments, as may be combined with the preceding paragraphs, where the steam treatment comprises steaming the catalyst under a steam and inert gas atmosphere at a temperature of at least about 500° C.
In one or more additional illustrative embodiments, as may be combined with the preceding paragraphs, where the catalyst is a fresh fluid catalytic cracking catalyst.
In one or more additional illustrative embodiments, as may be combined with the preceding paragraphs, where the catalyst comprises a ZSM-5 catalyst.
In one or more additional illustrative embodiments, as may be combined with the preceding paragraphs, where the fluidized catalytic cracking conditions comprise a temperature of 425° C. to about 650° C., a catalyst regeneration temperature of about 600° C. to about 800° C., a hydrocarbon partial pressure of about 100 to about 1100 kPa, a catalyst-to-oil ratio from about 2:1 to about 20:1, and a catalyst contact time of about 0.1 to about 15 seconds.
In one or more additional illustrative embodiments, as may be combined with the preceding paragraphs, the method is carried out in a fluid catalytic cracking unit.
In one or more additional illustrative embodiments, as may be combined with the preceding paragraphs, where processing the one or more waste plastic feedstocks in neat form in the presence of a catalyst under fluidized catalytic cracking conditions obtains a product stream comprising hydrocarbons.
In one or more additional illustrative embodiments, as may be combined with the preceding paragraphs, the method further comprises separating at least one hydrocarbon fraction from the product stream.
As used in this disclosure the word “comprises” or “comprising” is intended as an open-ended transition meaning the inclusion of the named elements, but not necessarily excluding other unnamed elements. The phrase “consists essentially of” or “consisting essentially of” is intended to mean the exclusion of other elements of any essential significance to the composition. The phrase “consisting of” or “consists of” is intended as a transition meaning the exclusion of all but the recited elements with the exception of only minor traces of impurities.
Various features disclosed herein are, for brevity, described in the context of a single embodiment, but may also be provided separately or in any suitable sub-combination. All combinations of the embodiments are specifically embraced by the illustrative embodiments disclosed herein just as if each and every combination was individually and explicitly disclosed. In addition, all sub-combinations listed in the embodiments describing such variables are also specifically embraced by the present compositions and are disclosed herein just as if each and every such sub-combination was individually and explicitly disclosed herein.
It will be understood that various modifications may be made to the embodiments disclosed herein. Therefore the above description should not be construed as limiting, but merely as exemplifications of preferred embodiments. For example, the functions described above and implemented as the best mode for operating the present invention are for illustration purposes only. Other arrangements and methods may be implemented by those skilled in the art without departing from the scope and spirit of this invention. Moreover, those skilled in the art will envision other modifications within the scope and spirit of the claims appended hereto.
Claims
1. A method, comprising:
- introducing one or more waste plastic feedstocks in neat form to a fluid catalyst cracking unit; and
- processing the one or more waste plastic feedstocks in neat form in the presence of a catalyst under fluidized catalytic cracking conditions.
2. The method according to claim 1, wherein the one or more waste plastic feedstocks comprise one or more polyesters, one or more polyolefins and combinations thereof.
3. The method according to claim 1, wherein the one or more waste plastic feedstocks comprise a low melting point polyethylene.
4. The method according to claim 1, wherein the one or more waste plastic feedstocks comprise a low melting point polyethylene having a melting point of from about 35° C. to about 100° C.
5. The method according to claim 1, wherein the one or more waste plastic feedstocks comprise one or more of a high density polyethylene, a low density polyethylene, a high molecular weight polyethylene, a low molecular weight polyethylene, polypropylene, polystyrene and combinations thereof.
6. The method according to claim 1, wherein introducing the one or more waste plastic feedstocks in neat form to a fluid catalyst cracking unit comprises introducing the one or more waste plastic feedstocks in neat form in a solid state to the fluid catalyst cracking unit.
7. The method according to claim 1, wherein introducing the one or more waste plastic feedstocks in neat form to a fluid catalyst cracking unit comprises introducing the one or more waste plastic feedstocks in neat form in a semi-melted state to the fluid catalyst cracking unit.
8. The method according to claim 1, wherein introducing the one or more waste plastic feedstocks in neat form to a fluid catalyst cracking unit comprises introducing the one or more waste plastic feedstocks in neat form in a melted state to the fluid catalyst cracking unit.
9. The method according to claim 1, wherein the catalyst is a fluid catalytic cracking catalyst.
10. The method according to claim 1, wherein the catalyst is a deactivated fluid catalytic cracking catalyst.
11. The method according to claim 1, wherein the catalyst is a deactivated fluid catalytic cracking catalyst discharged from a fluid catalytic cracking process, the catalyst having deactivating deposits accumulated thereon.
12. The method according to claim 11, wherein the deactivating deposits comprise at least one metal contaminant selected from the group consisting of sodium, potassium, magnesium, calcium, vanadium, nickel, iron, zinc and a mixture thereof.
13. The method according to claim 1, wherein the catalyst has been subjected to a steam treatment.
14. The method according to claim 13, wherein the steam treatment comprises steaming the catalyst under a steam and inert gas atmosphere at a temperature of at least about 500° C.
15. The method according to claim 1, wherein the catalyst is a fresh fluid catalytic cracking catalyst.
16. The method according to claim 1, wherein the catalyst comprises a ZSM-5 catalyst.
17. The method according to claim 1, wherein the fluidized catalytic cracking conditions comprise a temperature of 425° C. to about 650° C., a catalyst regeneration temperature of about 600° C. to about 800° C., a hydrocarbon partial pressure of about 100 to about 1100 kPa, a catalyst-to-oil ratio from about 2:1 to about 20:1, and a catalyst contact time of about 0.1 to about 15 seconds.
18. The method according to claim 1, which is carried out in a fluid catalytic cracking unit.
19. The method according to claim 1, wherein processing the one or more waste plastic feedstocks in neat form in the presence of a catalyst under fluidized catalytic cracking conditions obtains a product stream comprising hydrocarbons.
20. The method according to claim 19, further comprising separating at least one hydrocarbon fraction from the product stream.
Type: Application
Filed: Sep 7, 2023
Publication Date: Mar 13, 2025
Inventors: Tengfei Liu (Fairfield, CA), Joel Edward Schmidt (Oakland, CA), Richard L. Grove (Spanish Fort, AL)
Application Number: 18/243,192
