WO2024226776A1 - Method for producing pao-based circular products from recycled used oil feedstocks - Google Patents

Abstract

Processes for producing circular polyalphaolefins and polyalphaolefin-based products from used oils include the steps of introducing a used oil composition, or a feedstock containing a used oil composition and at least one other liquid, fuel, or oil, to a cracking unit to produce ethylene, oligomerizing the ethylene to form desirable normal α-olefins, oligomerizing the normal α-olefins into oligomers thereof, and hydrogenating the oligomers to form polyalphaolefins. The polyalphaolefin is mixed with additives and/or other oils to result in a product composition, which can be used in various end-use applications and then recycled into the process. In accordance with International Sustainability and Carbon Certificate standards, the product composition can be defined as circular, bio-circular, or bio- as determined by the mass balance attribution and/or the free attribution approach.

Description

METHOD FOR PRODUCING PAO-BASED CIRCULAR PRODUCTS FROM

RECYCLED USED OIL FEEDSTOCKS

REFERENCE TO RELATED APPLICATION

[0001] This application is being filed on April 25, 2024, as a PCT International Patent Application and claims the benefit of and priority to U.S. Provisional Patent Application No. 63/498,837. filed on April 28, 2023, the disclosure of which is incorporated herein by reference in its entirety.

FIELD OF THE INVENTION

[0002] The present disclosure generally relates to methods for making polyalphaolefins from used and recycled oil feedstocks to produce circular products, and more particularly, relates to performing such methods to produce circular, bio-circular, or bio- polyalphaolefins for use in lubricating oils, heat transfer fluids, and immersion cooling fluids.

BACKGROUND OF THE INVENTION

[0003] Waste petrochemical products can have a negative environmental impact. While demands for greener production have increased in recent years, recycling used oils remains an area of needed improvement. As of 2020, based on data from the Department of Energy, only about 30 percent of collected used oil of all types are re-processed into base stocks. The remaining collected used oils are often processed into other fuel products, burned directly for heating, or just disposed of into landfills or storm sewers. The demand for inventive reprocessing of used oils is abundant, however new reprocessing efforts need to provide enough incentive and must be easily integrated into existing processes to have an impact.

[0004] Other waste products, such as waste plastics, can be used to produce pyrolysis oil and create liquid hydrocarbon feedstocks, but the pyrolysis process is energy intensive. It would be beneficial to recycle used oil products - without pyrolysis - to produce ethylene and other useful hydrocarbon products. Accordingly it is to this end that the present invention is generally directed. SUMMARY OF THE INVENTION

[0005] This summary is provided to introduce a selection of concepts in a simplified form that are further described below in the detailed description. This summan is not intended to identify required or essential features of the claimed subject matter. Nor is this summary intended to be used to limit the scope of the claimed subject matter.

[0006] The present invention provides a method for recycling used oils as a feedstock or co-feedstock to produce circular polyalphaolefins (PAO) and PAO-based products. The general procedure begins with providing a used oil composition, or optionally combining the used oil composition with at least one other liquid, fuel, or oil, such as a fossil fuel, pyrolysis oil, bio-based liquid, natural gas liquid, or combinations thereof, to produce a feedstock. The used oil composition can contain one or more used Group I-V base stocks, and in some aspects, the used oil composition can comprise a heat transfer fluid, a bio-based oil, a dielectric fluid, a lubricant oil, an alpha-olefin wax, or any combination thereof. In some aspects, the used oil composition can be preprocessed by hydrotreatment, filtration, and/or distillation. The feedstock or the used oil composition then can be introduced into a cracking unit. This invention can lead to an unexpected increase in pure component cracking performance from 1 to 40% and a blend component cracking performance increase from 0.1 to 10%, as compared to an otherwise identical feedstock containing pyrolysis oil. Additionally, fouling in the cracking unit can be reduced by from 2 to 60% as compared to an otherwise identical feedstock containing pyrolysis oil. The cracking unit will transform the used oil composition into a cracking composition containing ethylene.

[0007] Ethylene is separated and isolated from other components in the cracking composition and then contacted with an ethylene oligomerization catalyst system in an ethylene oligomerization reactor. Other components of the cracking composition can be processed and/or recycled into the cracking unit. The ethylene oligomerization reactor can produce an oligomer product comprising Ce-Cso normal a-olefms, for instance, 1- hexene, 1 -octene, 1 -decene. and 1 -dodecene. The a-olefins are then fed into a PAO oligomerization reactor and the feedstock can be any combination of a-olefins, such as 1 -octene, 1 -decene, 1 -dodecene, and the like, or a mixture thereof. From the PAO oligomerization reactor, the PAO oligomer product can include dimers, trimers, tetramers, and/or pentamers of these a-olefin monomers. The oligomerization products in the mixture or as separated components can be hydrogenated to form polyalphaolefins.

0 In accordance with International Sustainability' and Carbon Certification (ISCC) provisions, the polyalphaolefins can be certified as circular, bio-circular, or biochemicals, based upon the weight or fraction of the circular, bio-circular, or biochemicals attributable to the used oil composition, as determined by mass balance attribution and/or the free attribution method, for example. Further, the circular, biocircular, or bio- PAOs. as a virgin quality Group IV base stock, can be used to prepare a number of products, such as a lubricant oil. a heat transfer fluid, an immersion cooling fluid, a dielectric fluid, and so forth. The circular polyalphaolefins can be detected by gas chromatography/mass spectrometry' (GC-MS) in the product composition and the used oil composition.

[0008] In the United States, only about 30 percent of collected used oil is reprocessed into lubricant base stocks; the remaining portion is either converted into other fuel oils or burned for industrial heating applications. The demand for more environmentally conscious production continues to grow, and the present invention presents an alternative recycling and reprocessing option by providing a method for producing virgin quality PAOs in a circular or bio-circular manner.

[0009] Both the foregoing summary and the following detailed description provide examples and are explanatory' only. Accordingly, the foregoing summary' and the following detailed description should not be considered to be restrictive. Further, features or variations may be provided in addition to those set forth herein. For example, certain aspects may be directed to various feature combinations and sub-combinations described in the detailed description.

BRIEF DESCRIPTION OF THE FIGURES

[0010] The following figures form part of the present specification and are included to further demonstrate certain aspects of the present invention. The invention may be better understood by reference to one or more of these figures in combination with the detailed description of specific embodiments presented herein.

[0011] FIG. 1 is a schematic flow diagram of a process for converting a used oil composition into polyalphaolefins and PAO-based products and exemplifies the cyclic nature of processes consistent with the present disclosure.

[0012] FIG. 2 is a bar chart comparing the aromaticity' and associated fouling between the used oil feedstock consistent with the present disclosure and other feedstocks that contain pyrolysis oil. [0013] While the inventions disclosed herein are susceptible to various modifications and alternative forms, only a few specific embodiments are described in detail below. The figures and detailed descriptions of these specific embodiments are not intended to limit the breadth or scope of the inventive concepts or the appended claims in any manner. Rather, the figures and detailed written descriptions are provided to illustrate the inventive concepts to a person of ordinary skill in the art and to enable such person to make and use the inventive concepts.

DEFINITIONS

[0014] To define more clearly the terms used herein, the following definitions are provided. Unless otherwise indicated, the following definitions are applicable to this disclosure. If a term is used in this disclosure but is not specifically defined herein, the definition from the IUPAC Compendium of Chemical Terminology, 2^nd Ed (1997), can be applied, as long as that definition does not conflict with any other disclosure or definition applied herein, or render indefinite or non-enabled any claim to which that definition is applied. To the extent that any definition or usage provided by any document incorporated herein by reference conflicts with the definition or usage provided herein, the definition or usage provided herein controls.

[0015] Herein, features of the subject matter are described such that, within particular aspects, a combination of different features can be envisioned. For each and every aspect and each and every feature disclosed herein, all combinations that do not detrimentally affect the processes or methods described herein are contemplated with or without explicit description of the particular combination. Additionally, unless explicitly recited otherwise, any aspect or feature disclosed herein can be combined to describe inventive processes or methods consistent with the present disclosure.

[0016] Generally, groups of elements are indicated using the numbering scheme indicated in the version of the periodic table of elements published in Chemical and Engineering News, 63(5), 27. 1985. In some instances, a group of elements can be indicated using a common name assigned to the group; for example, alkali metals for Group 1 elements, alkaline earth metals for Group 2 elements, transition metals for Group 3-12 elements, and halogens or halides for Group 17 elements.

[0017] The term “hydrocarbon’" whenever used in this specification and claims refers to a compound containing only carbon and hydrogen, whether saturated or unsaturated. Other identifiers can be utilized to indicate the presence of particular groups in the hydrocarbon (e.g., halogenated hydrocarbon indicates the presence of one or more halogen atoms replacing an equivalent number of hydrogen atoms in the hydrocarbon). Non-limiting examples of hydrocarbons include alkanes (linear, branched, and cyclic), alkenes (olefins), and aromatics, among other compounds.

[0018] For any particular compound or group disclosed herein, any name or structure (general or specific) presented is intended to encompass all conformational isomers, regioisomers, stereoisomers, and mixtures thereof that can arise from a particular set of substituents, unless otherwise specified. The name or structure (general or specific) also encompasses all enantiomers, diastereomers, and other optical isomers (if there are any) whether in enantiomeric or racemic forms, as well as mixtures of stereoisomers, as would be recognized by a skilled artisan, unless otherwise specified. For instance, a general reference to pentane includes n-pentane, 2-methyl-butane, and 2,2-dimethylpropane; and a general reference to a butyl group includes a n-butyl group, a sec-buty l group, an iso-butyl group, and a t-butyl group.

[0019] Unless otherwise specified, the term “substituted” when used to describe a group, for example, when referring to a substituted analog of a particular group, is intended to describe any non-hydrogen moiety that formally replaces a hydrogen in that group, and is intended to be non-limiting. Also, unless otherwise specified, a group or groups can also be referred to herein as “unsubstituted” or by equivalent terms such as “non-substituted,” which refers to the original group in which a non-hydrogen moiety does not replace a hydrogen within that group. Moreover, unless otherwise specified, “substituted” is intended to be non-limiting and include inorganic substituents or organic substituents as understood by one of ordinary skill in the art.

[0020] The terms “contacting” and “combining” are used herein to describe catalysts, compositions, processes, and methods in which the materials or components are contacted or combined together in any order, in any manner, and for any length of time, unless otherwise specified. For example, the materials or components can be blended, mixed, slurried, dissolved, reacted, treated, impregnated, compounded, or otherwise contacted or combined in some other manner or by any suitable method or technique.

[0021] In this disclosure, while processes and methods are described in terms of “comprising” various components or steps, the processes and methods also can “consist essentially of’ or “consist of’ the various components or steps, unless stated otherwise. The terms “a,” “an,” and “the” are intended to include plural alternatives, e.g., at least one, unless otherwise specified.

[0022] Several types of ranges are disclosed in the present invention. When a range of any type is disclosed or claimed, the intent is to disclose or claim individually each possible number that such a range could reasonably encompass, including end points of the range as well as any sub-ranges and combinations of sub-ranges encompassed therein. For example, the relative amount of aluminum to transition metal in certain catalyst systems can be in various ranges. By a disclosure that a molar ratio of Al to transition metal can be in a range from 10: 1 to 5,000: 1, the intent is to recite that the molar ratio can be any amount in the range and, for example, can include any range or combination of ranges from 10: 1 to 5,000: 1, such as from 50: 1 to 3.000: 1, from 75: 1 to 2,000: 1, or from 100: 1 to 1,000: 1, and so forth. Likewise, all other ranges disclosed herein should be interpreted in a manner similar to this example.

[0023] In general, an amount, size, formulation, parameter, range, or other quantity or characteristic is “about” or “approximate” whether or not expressly stated to be such. Whether or not modified by the term “about” or “approximately,” the claims include equivalents to the quantities or characteristics.

[0024] Although any methods, devices, and materials similar or equivalent to those described herein can be used in the practice or testing of the invention, the typical methods, devices, and materials are herein described.

[0025] All publications and patents mentioned herein are incorporated herein by reference in their entirety⁷ for the purpose of describing and disclosing, for example, the constructs and methodologies that are described in the publications and patents, which might be used in connection with the presently described invention.

DETAILED DESCRIPTION OF THE INVENTION

[0026] Current efforts to minimize the environmental impact of waste oils and waste plastic rely primarily on pyrolysis of waste plastics to produce liquid feedstocks and the conversion of used oils into heat or other fuel sources. These methods are energy intensive and may lead to increased carbon emissions. However, liquid feedstocks are an important resource for production of numerous chemicals. Advantageously, used oils can also be recycled to produce certain feedstocks, while not needing to undergo pyrolysis like waste plastics. Recycling used oils can help to minimize the environmental impact caused by the burning or improper disposal of used oil and can reduce the energy needs by providing an alternative to pyrolysis oils.

[0027] Another objective of this invention is to provide a circular process for utilizing a used oil source (such as used lubricant oil), ultimately converting the used oil into circular or bio-circular polyalphaolefins, which are then used to produce oil products, such as lubricant oil. In one aspect consistent with this invention, the process for converting used oils to a product containing virgin quality PAO base stocks can comprise (a) providing a used oil composition, (b) optionally, combining the used oil composition with at least one other liquid, fuel, or oil to produce a feedstock, (c) introducing the feedstock or the used oil composition into a cracking unit to produce a cracking composition comprising ethylene, (d) contacting the ethylene and an ethylene oligomerization catalyst system in an ethylene oligomerization reactor under ethylene oligomerization conditions to produce an oligomer product comprising C4-C30+ normal alpha olefins, (e) contacting an oligomerization catalyst composition with a feed stream comprising a Ce to C12 alpha olefin monomer in an oligomerization reactor under oligomerization conditions to produce an oligomerization product comprising oligomers (e.g., dimers, trimers, and/or tetramers) of the alpha olefin monomer, (I) hydrogenating at least a portion of the oligomerization product (e.g., alpha olefin trimer, a mixture of trimers and tetramers, etc.) to form a polyalphaolefin, and (g) preparing a product composition (such as a lubricant oil) comprising the polyalphaolefin.

USED OIL COMPOSITION OR FEEDSTOCK

[0028] Generally, the oils encompassed by this invention are recycled from mechanical components and are used to reduce friction, heat, or wear. However, for bio- or bio-circular sources, the oil can be a bio-based oil (e.g., vegetable oils, peanut oils, olive oils, canola oils, and the like) used for cooking or other applications. During the period of use, such as a lubricant, the oil experiences a reduction in its capacity to perform its intended purpose and can accumulate contaminants. A non-limiting list of examples of used oil sources includes wind turbine oils, engine oils, transmission fluids, CVT fluids, axle fluids, industrial gear oils, compressor oils, dielectric fluids, immersion cooling fluids, hydraulic fluids, fiber optic cable filling gels, drilling fluids, oils used in lotions and creams, shampoos, hair care products, greases, gas turbine lubricants, heat transfer fluids, metal-working fluids, textile fluids, bearing oils, bio-based oils (e.g.. used vegetable oils), alpha-olefin waxes, guns oils, and the like. In some aspects, the used oil composition can contain heat transfer fluids, dielectric fluids, immersion cooling fluids, bio-based oils, alpha-olefin waxes, and the like, as well as combinations thereof. The used oils can contain one or more used Group I-V base stocks and can contain various additives depending upon the end-use application.

[0029] In one aspect, the used oil composition is provided alone, while in another aspect, the used oil composition may be combined with at least one other liquid, fuel, or oil. such as (but not limited to) fossil fuels, pyrolysis oils (e.g., pyrolysis oils produced from waste plastics), bio-based liquids, and/or natural gas liquids. The combination of one or more other oils with the used oil composition can occur through any suitable method of mixing, blending, agitating, or any combination thereof, to produce a feedstock. The weight ratio of the used oil composition to the at least one other liquid, fuel, or oil in the feedstock often ranges from 1 :99 to 90: 10, such as from 2:98 to 25:75. The feedstock (or the used oil composition) generally contains less than or equal to 15 wt. % pyrolysis oil. In some aspects of the present invention, used oils and light natural gas liquids, such as C4 and Cs hydrocarbons (and often up to C7) are mixed to produce a blended feedstock.

[0030] The used oil composition or feedstock can be characterized by important physical properties, specifically the kinematic viscosity' (KV) at 100 °C, viscosity' index (VI), and flashpoint. The used oil composition or feedstock can be characterized by a KV100 of from 2 to 150 cSt, a VI of from 80 to 210, and/or a flashpoint greater than or equal to 130 °C. In aspect, the used oil composition can contain used circular, biocircular, and/or bio-based polyalphaolefins.

[0031] Additionally, the used oil composition or feedstock will often contain contaminants, specifically calcium (Ca) and zinc (Zn)-based additives along with modifiers containing sulfur (S) and oxygen (O). However, the used oil composition or feedstock can contain less than 1 wt. % independently of Ca, Zn, S, and O. In some instances, the amount of Zn in the used oil composition is less than 5 ppm, 4 ppm, 3 ppm, or 2 ppm, and the amount of S in the used oil composition is less than 0.9 wt. %, 0.8 wt. %. 0.7 wt. %. or 0.6 wt. %. Antioxidants may be combined with the used oil composition or feedstock to improve stability. The antioxidant may be natural or synthetic and can be combined with the used oil composition or feedstock to achieve a concentration of less than 2500 mmol of antioxidant per kilogram of used oil composition or feedstock. The natural antioxidant can be selected from a plant-based, animal-based, or a bioactive peptide, or any combination thereof; the synthetic antioxidant can be selected from a hindered phenol, a metal salt of a hindered phenol, an oil-soluble polymetal organic compound, a hindered phenylenediamine compound, diphenylamines, phenyl naphthylamines, phenothiazines, imidodibenzyls, diphenyl phenylene diamines, aromatic amines, p,p’ -dioctyldiphenylamine, t-octlyphenyl-alphapnaphthylamine, phenyl-alpha-napthylamine, p-octylphenyl-alpha-naphthylamine, or combinations thereof. Typical antioxidants are disclosed, for example, in U.S. Patent Publication No. 2022/0098490.

[0032] Although not required, the used oil composition or feedstock can be preprocessed by hydrotreatment, fdtration, distillation, or any combination thereof, or alternatively, filtration and/or distillation. Preprocessing reduces or removes contaminants and can help streamline production. A non-limiting list of unit operations that may be included in preprocessing are hydroprocessing units, separation units, distillation units, refinery units, liquid-liquid extractors, and/or filtration units. Distillation units can help to remove residues and provide a more uniform product for cracking. Liquid-liquid extraction can be used to remove poly-aromatics. Hydroprocessing can be used to remove heteroatoms, such as sulfur, oxygen, nitrogen, and chlorine. Silicon also can be removed, if desired. Additionally, a portion of the used oil composition or the feedstock can bypass the cracking unit and enter a separation unit downstream of the cracking unit. The resulting treated composition can then be recycled into the cracking unit.

[0033] Lastly, before entering the cracking unit, the used oil composition or feedstock can be dewatered to less than 1 wt. % water. The dewatering unit can be selected from, but not limited to, a coalescer, a decanter, a resin-based water absorption unit, a pervaporation unit, a membrane based dewatering unit, or combinations thereof.

CRACKING TO PRODUCE ETHYLENE

[0034] In step (c), the used oil composition or feedstock is introduced into a cracking unit to produce a cracking composition containing ethylene. Ordinarily, the cracking unit can comprise a steam cracker and/or a fluid catalytic cracker. Thus, the cracking unit can be a single stream cracker, a single fluid catalytic cracker, or a steam cracker and fluid catalytic cracker in series or in parallel.

[0035] If the cracking unit comprises a steam cracker, the steam cracker can operate at a temperature within the range of from 700 to 950 °C and a residence time of from 10-1000 ms, although not limited thereto. The used oil composition or feedstock to steam volumetric ratio can range from 0.1 : 1 to 1.5: 1 and the weight ratio of steam to hydrocarbons in the feedstock or used oil composition can be at least 0.4: 1. while also not being limited thereto. If the cracking unit comprises a fluid catalytic cracker, any suitable cracking catalyst can be utilized in the fluid catalytic cracker. Non-limiting examples include zeolitic catalysts, bauxites, silica-aluminas, aluminum hydrosilicates, aluminas with zeolite modifiers, and the like. Combinations of two or more catalysts can be used, if desired.

[0036] The cracking unit typically produces a mixture of olefins, including ethylene, propylene, butene, butadiene, and the like, with ethylene being the predominant product in the cracking composition. In some aspects, the cracking unit can additionally produce aromatics, such as benzene, toluene, xylene, and so forth, as well as light (C2- C3) saturated hydrocarbons.

[0037] Beneficially, as compared to the cracking of pyrolysis oil, the cracking of the used oil composition (with less aromatics and lower levels of contaminants) produces a greater amount of ethylene. Thus, the cracking unit has an improved cracking performance as compared to cracking of an otherwise identical feedstock containing pyrolysis oil rather than the used oil composition. For instance, the processes described herein can result in a pure component cracking performance increase (based only on the amount of the used oil composition in the feedstock) from 1 to 40% or from 10 to 40%, and/or can result in a blend component cracking performance increase (based on the blended feedstock) from 0.1 to 10% or from 0.2 to 5%. Additionally, the present invention can result in decreased fouling in the cracking unit as compared to cracking of an otherwise identical feedstock containing pyrolysis oil rather than the used oil composition. Fouling in the cracking unit can be reduced by from 2 to 60%, although not limited thereto.

[0038] Additionally, the cracking composition containing ethylene can be separated using any suitable means of separation, such as filtration, distillation, etc., in order to isolate ethylene from the remainder of the cracking composition. It is beneficial to isolate a high purity ethylene stream from the cracking composition prior to the ethylene oligomerization step of the process.

CONVERTING ETHYLENE INTO NORMAL a-OLEFINS

[0039] The processes disclosed herein comprise a step of contacting the ethylene and an ethylene oligomerization catalyst system in an ethylene oligomerization reactor under ethylene oligomerization conditions to produce an oligomer product comprising C4-C30- normal alpha olefins (ethylene-based oligomers). Oligomerization catalyst compositions, oligomerization reactors, oligomerization conditions, and resulting ethylene oligomer products are well known to those of skill in the art. Briefly, an oligomerization process using ethylene as the monomer produces a mixture of products comprising at least 30 wt. %, 50 wt. %, 60 wt. %. or 70 wt. % oligomers having from 4 to 40 carbon atoms, or from 4 to 20 carbon atoms, such as a total amount of Cw olefins and C's olefins of least 50 wt. %, 65 wt. %, 75 wt. %, or 80 wt. %. Likewise, any suitable amount of C10 olefins and C12 olefins, such as 1 -decene and 1 -dodecene can be produced.

[0040] Although not limited thereto, the oligomerization catalyst composition can be a transition metal-based catalyst system. A particular example of an oligomerization catalyst composition can include a heteroatomic ligand transition metal compound complex and an organoaluminum compound, or a heteroatomic ligand, a transition metal compound, and an organoaluminum compound. Examples of representative and non-limiting oligomerization catalyst compositions - and ethylene oligomerization processes and reactor systems -include those disclosed in U.S. Patent Publication Nos. 2017/0081257, 2017/0341998, 2017/0341999, 2017/0342000, 2017/0342001, and 2016/0375431, and in U.S. Patent Nos. 10,493,422, 10,464,862, 10,435,336, 10,689,312, and 10,807,921. Generally, the organoaluminum compound can be an aluminoxane, an alkylaluminum compound, or a combination thereof. Representative aluminoxanes include methylaluminoxane (MAO), ethylaluminoxane, modified methylaluminoxane (MMAO), n propylaluminoxane, iso-propyl-aluminoxane, n-butylaluminoxane, sec-butylaluminoxane, iso-butylaluminoxane, t-butylahiminoxane. l-penl laluminoxane. 2-entylaluminoxane, 3-penlyl-aluminoxane. iso-pentyl- aluminoxane, neopentylaluminoxane, and the like, while representative alkylaluminums include trimethylaluminum, triethylaluminum, tripropylaluminum, tributylaluminum, trihexylaluminum, trioctylaluminum, and the like. Often, the Al to transition metal molar ratio of the catalyst system can be in a range from 10: 1 to 5,000: 1, from 50: 1 to 3,000: 1, from 75: 1 to 2.000: 1, or from 100: 1 to 1,000:1.

[0041] The oligomerization reactor in which the ethylene oligomer product is formed can comprise any suitable reactor, and non-limiting examples of reactor ty pes can include a stirred tank reactor, a plug flow reactor, or any combination thereof; alternatively, a fixed bed reactor, a continuous stirred tank reactor, a loop reactor, a solution reactor, a tubular reactor, a recycle reactor, or any combination thereof. In an aspect, the oligomerization reactor system can have more than one reactor in series and/or in parallel and can include any combination of reactor types and arrangements. Moreover, the oligomerization process used to form the ethylene oligomer product can be a continuous process or a batch process, or any reactor or reactors within the oligomerization reaction system can be operated continuously or batchwise. An organic reaction medium can be present in the oligomerization reactor, and although not limited thereto, the organic reaction medium can comprise a saturated aliphatic hydrocarbon, an aromatic hydrocarbon, a linear alpha-olefin, or any combination thereof.

[0042] A suitable oligomerization temperature typically falls within a range from 0 to 160 °C, and more often, the oligomerization temperature is from 40 to 150 °C, from 60 to 130 °C, from 60 to 115 °C. from 70 to 115 °C. from 70 to 100 °C. or from 75 to 95 °C. Suitable pressures will also vary according to the reactor type, but generally, oligomerization pressures fall within a range from 50 psig to 3000 psig. More often, the pressure ranges from 200 psig to 2000 psig, from 400 psig to 1500 psig, from 600 psig to 2000 psig. from 600 psig to 1300 psig, from 700 psig to 1500 psig, or from 700 psig to 1200 psig.

[0043] The ethylene oligomer product can contain C4+ hydrocarbons and generally the vast majority' of the ethylene oligomer product is C6-C12 olefins. Thus, the ethylene oligomers include Ce olefins (e.g.. 1 -hexene), Cs olefins (e.g., 1 -octene). C10+ olefins (e.g.. 1-decene and 1-dodecene), and even C30+ olefins. In an aspect, the major ethylene oligomer in the oligomer product is 1 -hexene, while in another aspect, the major ethylene oligomer in the oligomer product is 1 -octene, and in yet another aspect, the major ethylene oligomers in the oligomer product are 1-hexene and 1-octene (a mixture thereof).

[0044] In one aspect, the oligomer product comprises C6-C30 normal a-olefms, while in another aspect, the oligomer product comprises Ce-Cio normal a-ol efins, and in yet another aspect, the oligomer product comprises 1-hexene and 1-octene. As a general rule, the total amount of Ce olefins and Cs olefins - based on the total weight of oligomers in the ethylene oligomer product - can be at least 50 wt. %, and more often, at least 65 wt. %, at least 75 wt. %, or at least 90 wt. %, although not limited thereto. After the ethylene oligomer product is discharged in an effluent stream (containing unreacted ethylene and the oligomer product, among other materials) from the oligomerization reactor, the various components can be separated or fractionated into various ethylene oligomer product streams, such as a 1-hexene stream, a 1-octene stream, a 1-decene stream, a 1 -dodecene stream, or combinations of one or more, from the oligomer product. Separations can use any suitable technique, including but not limited to extraction, filtration, evaporation, distillation, the like, and any combination thereof. Isolated unreacted ethylene can be recycled back into the ethylene oligomerization reactor. The isolated a-olefin streams (or mixtures thereof) can be utilized as feed streams to the next oligomerization step.

NORMAL a-OLEFINS OLIGOMERS

[0045] The processes disclosed herein can further comprise a step of contacting an oligomerization catalyst composition with a feed stream comprising a C6 to C12 alpha olefin monomer in an oligomerization reactor under oligomerization conditions to produce an oligomerization product comprising oligomers (e.g., dimers, trimers, and/or tetramers) of the alpha olefin monomer. Generally, the feed stream comprises the alpha olefin monomer and from 0.1 to 99 wt. % of the 1 -hexene stream, the 1 -octene stream, the 1 -decene stream, the 1 -dodecene stream, or any combination thereof, that was formed in the prior step. Oligomerization catalyst compositions, oligomerization reactors, oligomerization conditions, and resulting oligomerization products are well known to those of skill in the art.

[0046] Briefly, oligomerization catalyst compositions that are suitable for use herein include, but are not limited to, a Ziegler-Natta based catalyst system, a chromium- based catalyst system, a metallocene-based catalyst systems, a Lewis acid system, an acid clay, an aluminum halide, a peroxide, an ionic liquid catalyst, and the like, including combinations thereof. An exemplar}' Lewis acid catalyst system can include boron trifluoride with a protic promoter.

[0047] The oligomerization reactor can include any oligomerization reactor capable of producing dimers, trimer, tetramers, pentamers, and/or higher oligomers of normal a-olefins. The various ty pes of oligomerization reactors include those that can be referred to as a stirred tank reactor, a plug flow reactor, a fixed bed reactor, a continuous stirred tank reactor, a loop reactor, a solution reactor, a tubular reactor, a recycle reactor, or any combination thereof.

[0048] The oligomerization conditions for the various reactor ty pes are well known to those of skill in the art. Representative oligomerization temperatures are from 20° C to 180° C. from 50° C to 160° C. from 70° C to 140° C. from 70° C to 90° C, or from 90° C to 120° C, although not limited thereto. The oligomerization product can contain oligomers of C6-C12 alpha-olefin monomers. In an aspect, oligomerization product comprises dimers, trimers, and tetramers, while in another aspect, the oligomerization product comprises trimers of the C6-C12 alpha-olefin monomer(s).

[0049] Further, the process can comprise discharging an effluent stream, which contains unreacted alpha olefin monomer and the oligomerization product, from the oligomerization reactor. The effluent stream may also contain the oligomerization catalyst, which can be separated from the oligomerization product. Unreacted alpha olefin monomer can be recycled into the oligomerization reactor. The oligomerization product can be separated into fractions (e.g., dimer, trimer, tetramer) or mixed in any suitable proportion. Whether in a desired mixture or isolated, these normal a-olefin oligomers can be subsequently hydrogenated.

HYDROGENATION TO FORM POLYALPHAOLEFINS

[0050] The processes described herein can further comprises a step of hydrogenating at least a portion of the oligomerization product (e.g., alpha olefin trimer, a mixture of tnmers and tetramers, etc.) to form a polyalphaolefin. The process of hydrogenation is well defined and known to those skilled in the art. Generally, metallic hydrogenation catalysts (e.g., cobalt, nickel, palladium, and platinum), which can be supported on a suitable carrier, e.g., aluminas, silica gels, silica-alumina composites, silica-coated aluminas, zeolites, silica-aluminophosphates, or combinations thereof, are often used. The amount of metal component present in the supported catalyst is ty pically from 0.1 to 20 wt. %, from 0.3 to 10 wt. %, or from 0.1 to 5 wt. %. Catalyst selection and hydrogenating conditions are generally selected to promote hydrogenation of the oligomerization product while preventing hydrocracking thereof.

[0051] The hydrogenation can be performed in the presence of hydrogen in any suitable reactor, such as a batch reactor or continuously in a fixed bed, fluidized bed or slurry phase reactor. Hydrogenation conditions can include temperatures of from 149 to 316 °C, from 150 to 350 °C, from 200 to 400 °C, or from 250 to 350 °C. The reaction is maintained at a pressure of from 300 to 3000 psig, although not limited thereto.

[0052] The flow rate, in terms of Liquid Hourly Space Velocity (LHSV), calculated as the volume of the liquid oligomerization product fed to the hydrogenation reactor per unit volume of hydrogenation catalyst per hour, can be in the range from 0.1 to 20 h ¹. or from 0.1 to 5 h ¹. The H2 feed stream can contain any suitable amount of hydrogen gas, e.g., 50 wt. % hydrogen gas or more, with the remainder being inert diluents. The exit gas stream containing unreacted H2 gas can be treated and recycled back into the hydrogenation reactor. While not being limited thereto, the H2 feed stream enters the hydrogenation reactor at a feed ratio of hydrogen feed stream to oligomerization product stream from 100 to 1750 m³/m³ or from 150 to 600 m7m³.

[0053] The resulting polyalphaolefin can be characterized by the following target physical properties: a flashpoint (as measured by a standard method such as ISO:2719) greater than or equal to 130 °C, a pour point (as measured by a standard method such as ASTM D97 or 180:3016) of less than or equal to 20 °C, a kinematic viscosity (KV100) (as measured by a standard method such as ASTM D445 or ISO: 3104) in a range from 1.5 to 300 cSt, and/or a viscosity index in a range from 80 to 210.

[0054] Additionally, in accordance with International Sustainability and Carbon Certification (ISCC) provisions, the polyalphaolefins can be certified as circular, biocircular, or bio- chemicals, based upon the weight or fraction of the circular, bio-circular, or bio- chemicals attributable to the used oil composition, as determined by mass balance attribution and/or the free attribution method, for example. Given that chemically recycled or bio-based feedstocks are often blended in production, the ISCC system provides an approach to track the amount of sustainable chemicals throughout complex processing schemes. The mass balance and free attribution method allows for characterization and tracking of recycled materials throughout processing and defines products that are capable of being reprocessed, broken down, and upgraded into virgin quality base stocks or feedstocks as circular based on the assumption a mixed feedstock containing a recycled oil and other oils used a portion of the recycled oil to produce the base stock or product. Bio- or bio-circular refers to production of virgin quality base stocks or feedstocks from unused or used biofuels or bio-oils in a similar manner. Circular, bio-circular, and bio- products are intended to promote sustainability' and reduce waste and carbon emissions from chemical production. In an aspect, the circular product is certified as circular in accordance with ISCC standards, based upon the weight or fraction of the circular product attributable to the pyrolysis oil or plastic waste or used lubricating oil determined by mass balance and the free attribution method.

APPLICATIONS OF PAO AND PAO-BASED PRODUCTS

[0055] The processes described herein can further comprise a step of preparing a product composition comprising the PAO (e.g.. a lubricant oil). The PAOs produced as described can be used as virgin quality Group IV base stock. Therefore, the application of PAO-based products is extensive. Products can be formed from a single polyalphaolefin, a mixture of polyalphaolefins, one or more additives, and/or one or more base oils. Suitable additives include detergents, friction modifiers, dispersants, viscosity modifiers, dispersant viscosity modifiers, viscosity index improvers, pour point depressants, anti-wear additives, rust inhibitors, corrosion inhibitors, antioxidants, seal swell agents, extreme pressure additives, surfactants, demulsifiers, anti-seizure agents, wax modifiers, lubricity agents, anti-staining agents, chromophoric agents, and metal deactivators, as well as any mixture thereof. Although not limited thereto, the product composition can be a lubricant oil, a heat transfer fluid, an immersion cooling fluid, or a dielectric fluid.

[0056] The product composition can be used in any suitable application and recycled into the used oil composition. PAOs produced by the disclosed methods may be detected in products and used oil compositions by means of gas chromatography/mass spectrometry (GC-MS), where the presence of repeating oligomers identifies the PAO as being distinctly different from mineral oil base stocks (e g., Group I-III). For example, 1 -decene based PAOs will have dimers (C20), trimers (C30), tetramers (C40), and so forth. Oligomers from other alpha olefins will have multiples from the starting monomers as well, such as 1 -dodecene monomer resulting in dimers (C24), trimers (C36), tetramers (C48), and so forth. In contrast, mineral oils will give every carbon number. Therefore, a blend of PAO with mineral oils (e.g., Groups I-III base stocks) will show an admixture in the GC chromatogram. Deconvoluting the chromatogram can identify the type and amount of oligomer and characterize the amount of PAO (and even the approximate viscosity of the PAO in the mixture). It is normally expected to be able to detect about 1 wt. % or more of the PAO in a mixture with reasonable analysis.

[0057] Referring now to FIG. 1, which illustrates a schematic flow diagram of a process 100 for converting a used oil composition into polyalphaolefins and PAO-based products and exemplifies the cyclic nature of processes consistent with the present disclosure. A used oil stream 101 is combined with at least one other liquid, fuel, or oil stream 102 in a blending unit 103 to produce a feedstock 104. The feedstock 104 is introduced into a cracking unit 105. The cracking unit 105 produces a cracking composition comprising ethylene 106. The ethylene 106 is introduced into the ethylene oligomerization unit 107. which produces ethylene-based oligomers (normal alpha olefins, NAOs 108). One or more NAOs 108 are introduced to an oligomerization unit 109 to produce an oligomer product stream 110. The oligomer product stream 110 is hydrogenated in a hydrogenation unit 111 to produce a polyalphaolefin (PAO) stream 112. In a product mixing unit 114, at least additives 113 and the polyalphaolefin stream 112 are combined, resulting in a product oil composition 1 15. The product oil composition 115 can be used in various end-use applications 116 and then recycled. The used oil stream 117 is recycled into the used oil stream 101.

EXAMPLES

[0058] The invention is further illustrated by the following examples, which are not to be construed in any way as imposing limitations to the scope of this invention. Various other aspects, modifications, and equivalents thereof which, after reading the description herein, can suggest themselves to one of ordinary skill in the art without departing from the spirit of the present invention or the scope of the appended claims.

EXAMPLE A

[0059] FIG. 2 demonstrates the differences in aromaticity and predicted fouling (in transfer line exchangers, TLE) between the used oil feedstock (Example 1. used vacuum gas oil) consistent with the present disclosure and pyrolysis oil feedstocks (Comparative Examples 2-4, three different commercially produced pyrolysis oils). The Bureau of Mines Correlation Index (BMCI) is an empirical correlation that calculates a number based on the physical properties of a feedstock to compare the relative tendency of different feedstocks (with different properties) to foul the TLE (Transfer Line Exchanger) and increase outlet temperature on an ethane cracking or steam cracking furnace. The BMCI is an indicator of aromaticity and can be estimated using the specific gravity and the distillation curve analysis of a specific feedstock. Aromaticity has a large impact on cracking performance and fouling, where reduced aromaticity (lower BMCI) correlates with improved cracking performance and reduced fouling. As shown in FIG. 2, the BMCI for Example 1 (used oil feedstock) was about 16-18. In contrast, the BMCI values for Comparative Examples 2-4 (various grades of pyrolysis oil) were in the 20-40 range. Thus, the used oil feedstock of Example 1 is a superior feedstock for cracking than the pyrolysis oils based on lower aromaticity, and this would result in improved cracking performance and decreased fouling. It is also believed that the used oil feedstock has lower contaminant levels of silicon and chlorine versus the pyrolysis oils. Lower chloride content and lower silicon content generally allow for higher concentrations of the feedstock to be fed to the cracking unit, resulting in improved production efficiency in the use of a used oil feedstock as compared to pyrolysis oil.

EXAMPLE B

[0060] In Example B, a mixture of n-butane and 8-9 wt. % of Example 1 (used vacuum gas oil) was used as the feedstock to a steam cracking unit. The feed mixture containing 8-9 wt. % used vacuum gas oil was fed to two separate furnaces in the steam cracking unit, effectively producing two usable data sets. The duration of the test was determined based on the amount of material provided and the desire to maintain a concentration of 8-9 wt. % of used vacuum gas oil in the feed stream during the test.

[0061] The steam cracking unit is a world-scale facility capable of producing over 1 billion pounds of polymer grade ethylene and 1 billion pounds of propylene annually. The unit is made up of 14 individual cracking furnaces, each receiving a liquid feed stream. The unit can feed ethane, propane, and liquid feed streams such as naphtha, natural gasoline, butane, normal pentane, and iso-pentane, or mixtures thereof. Upstream of the cracking furnaces are a feed filter unit and a feed drum, through which all feed is processed before entering the furnaces. A mixture of feedstock and steam flows through each furnace where it is “cracked'’ to produce ethylene and propylene, as well as other byproducts.

[0062] For comparison, a mixture of n-butane and 4.2-6.6 wt. % of Comparative Example 2 (pyrolysis oil) and a mixture of n-butane and 6.6-7.7 wt. % of Comparative Example 4 (pyrolysis oil) were also used as blended feedstocks. The temperature change in the furnace outlet from the beginning of the run to the end of the run was monitored. Table 1 summarizes the results.

[0063] The minimum, maximum, and average TLE outlet temperature data for all three test runs is shown in Table 1 below. The minimum, maximum, and average values are based on data points collected at 1 min intervals. Referring first to Comparative Example 4, in only 9 hr of operation the TLE outlet temperature increased significantly, approximately 13-15 °F, over the duration of the test. Although some variability in the TLE outlet temperature can be expected during normal operation, a plot of all the TLE outlet temperature data (data not show n) showed a steep linear increase in temperature from about 744 °F to about 759 °F over almost the entire duration of the test. This large and constant temperature increase is indicative of significant fouling in the furnace. [0064] The temperature during the 14-hr evaluation of Comparative Example 2 was substantially constant, but the relative amount in the feedstock was less than that of both Comparative Example 4 and Example 1. Based on the BMCI correlation based on feedstock properties and observations of the TLE outlet temperature during the test run, it is expected that this material would cause some fouling if run in greater amounts and/or for longer periods of time.

[0065] Advantageously and unexpectedly, the temperature during the 9-hr evaluation of Example 1 was substantially constant, but with a much higher relative amount of used vacuum gas oil in the combined feedstock than that of Comparative Example 4 (8-9 wt. % vs 6.6-7.7 wt. %). Further, as compared to Comparative Example 2, the relative amount of Example 1 in the feedstock was nominally 50% greater than that of Comparative Example 2, yet there was no difference in fouling performance (no temperature change). Thus, the used oil feedstock of Example 1 can likely be fed to the furnace at much higher amounts than the pyrolysis oil of Comparative Example 2 (or Comparative Example 4) with the same or better operational performance. This is an important observation because, if small amounts of feedstock (used vacuum gas oil or pyrolysis oil) cause a temperature increase, then it is expected that feeding larger amounts of feedstock will cause an even greater temperature increase. Since a temperature increase is a direct indicator of fouling, it can be concluded that fouling of the furnace TLE will also increase. Fouling of the TLE will ultimately shorten the runlife of the furnace before it has to be shut down; therefore, from an operational and economic standpoint, it is preferable to feed materials that cause less fouling.

[0066] Furthermore, the used vacuum gas oil of Example 1 was used “as- received”, meaning no additional processing was performed before feeding the material to the furnace. In comparison, in order to reduce the potential of fouling from the pyrolysis oil, the pyrolysis oil would need to be further processed (by distillation, hydrotreating, hydrocracking, filtration, or any number of other means known to those of skill in the art) prior to feeding the pyrolysis oil to the furnace. Used vacuum gas oil is also a waste product generated by other processes, whereas pyrolysis oil is made via the pyrolysis of solid plastic waste or organic materials such as biomass. Pyrolysis of waste plastic, biomass or other appropriate materials is an energy -intensive process in and of itself due to the high temperatures (500-1700 °F) required to degrade solid plastic waste. When considering the energy demand of an overall process, it is desirable to use a feedstock that requires less energy to produce. This suggests that the vacuum gas oil (or other used oil composition) is a preferable feedstock as compared to pyrolysis oil in order to minimize the amount of energy’ required to produce a circular and/or recycled product.

Table 1

[0067] The invention is described above with reference to numerous aspects and specific examples. Many variations will suggest themselves to those skilled in the art in light of the above detailed description. All such obvious variations are within the full intended scope of the appended claims. Other aspects of the invention can include, but are not limited to, the following (aspects are described as “comprising” but, alternatively, can “consist essentially of’ or “consist of’):

[0068] Aspect 1. A process (e.g., for recycling used oil) comprising:

(a) providing a used oil composition;

(b) optionally, combining the used oil composition with at least one other liquid, fuel, or oil to produce a feedstock;

(c) introducing the feedstock or the used oil composition into a cracking unit to produce a cracking composition comprising ethylene; and

(d) contacting the ethylene and an ethylene oligomerization catalyst system in an ethylene oligomerization reactor under ethylene oligomerization conditions to produce an oligomer product comprising C4-C30+ normal alpha olefins.

[0069] Aspect 2. The process defined in aspect 1. wherein the used oil composition is recycled from any suitable source, e.g.. wind turbine lubricants, engine oils, transmission fluids, CVT fluids, axle fluids, industrial gear oils, compressor oils, dielectric fluids, heat transfer fluids, immersion cooling fluids for computers, hydraulic fluids, fiber optic cable filling gels, drilling fluids, oils used in lotions and creams, shampoos, hair care products, greases, gas turbine lubricants, metal-working fluids, textile fluids, bearing oils, bio-based oils, vegetable oils, alpha-olefin waxes, gun oils, or any combination thereof.

[0070] Aspect 3. The process defined in aspect 1 or 2, wherein the used oil composition contains used circular, bio-circular, and/or bio-based polyalphaolefins.

[0071] Aspect 4. The process defined in any one of aspects 1-3, wherein the used oil composition contains one or more used Group I-V base stocks.

[0072] Aspect 5. The process defined in any one of aspects 1-4, wherein the used oil composition is preprocessed by hydrotreatment, filtration and/or distillation before (b).

[0073] Aspect 6. The process defined in any one of aspects 1-5, wherein the used oil composition contains less than 1 wt. %, independently, of Ca, Zn, S, and O.

[0074] Aspect 7. The process defined in any one of aspects 1-6, wherein the used oil composition is characterized by a KV of from 2 to 150 cSt at 100 °C, a VI of from 80 to 210, a flashpoint greater than or equal to 130 °C, or any combination thereof.

[0075] Aspect 8. The process defined in any one of aspects 1-7, wherein a portion of the used oil composition enters a separation unit dow stream of the cracking unit and the resulting treated composition is recycled into the cracking unit.

[0076] Aspect 9. The process defined in any one of aspects 1-8, wherein combining in (b) comprises mixing, blending, agitating, or any combination thereof.

[0077] Aspect 10. The process defined in any one of aspects 1 -9, wherein the at least one other liquid, fuel, or oil in (b) comprises a fossil fuel, a pyrolysis oil, a biobased liquid, a natural gas liquid, or any combination thereof.

[0078] Aspect 11. The process defined in any one of aspects 1-10. wherein a weight ratio of the used oil composition to at least one other liquid, fuel, or oil in the feedstock is in a range from 1 :99 to 90: 10, or from 2:98 to 25:75.

[0079] Aspect 12. The process defined in any one of aspects 1-11, wherein the feedstock (or the used oil composition) contains less than or equal to 15 wt. % pyrolysis oil.

[0080] Aspect 13. The process defined in any one of aspects 1-12, wherein the feedstock (or the used oil composition) contains less than or equal to 1 wt. % water (e.g., the feedstock, or any component of the feedstock, can be dewatered prior to (c)).

[0081] Aspect 14. The process defined in any one of aspects 1-13, wherein the cracking unit comprises a steam cracker and/or a fluid catalytic cracker. [0082] Aspect 15. The process defined in any one of aspects 1-14, wherein the cracking unit (e.g., steam cracker) operates at a weight ratio of steam:hydrocarbons in the feedstock (or the used oil composition) of at least 0.4: 1 , a temperature in a range from 700 to 950 °C, a residence time of from 10 to 1000 ms, and a feedstock: steam (or used oil composition: steam) volumetric ratio in a range from 0.1: 1 to 1.5: 1.

[0083] Aspect 16. The process defined in any one of aspects 1-15, wherein the cracking unit comprises a fluid catalytic cracker, which includes any suitable cracking catalyst, e.g., a zeolitic catalyst, bauxite, silica-alumina, aluminum hydrosilicate, alumina with zeolite modifiers, or combinations thereof.

[0084] Aspect 17. The process defined in any one of aspects 1-16, wherein the process results in a pure component cracking performance increase from 1 to 40% or from 10 to 40%, and/or results in a blend component cracking performance increase from 0.1 to 10% or from 0.2 to 5%, as compared to an otherwise identical feedstock that contains pyrolysis oil instead of the used oil composition.

[0085] Aspect 18. The process defined in any one of aspects 1-17. wherein fouling in the cracking unit is reduced by any suitable amount, e.g.. from 2 to 60%, as compared to an otherwise identical feedstock that contains pyrolysis oil instead of the used oil composition.

[0086] Aspect 19. The process defined in any one of aspects 1-18, wherein the process further comprises a step of isolating/separating the ethylene from the cracking composition between (c) and (d).

[0087] Aspect 20. The process defined in any one of aspects 1-19, wherein step (d) comprises contacting the ethylene, the ethylene oligomerization catalyst system, and an organic reaction medium in the oligomerization reactor, wherein the organic reaction medium comprises a saturated aliphatic hydrocarbon, an aromatic hydrocarbon, a linear a-olefin, or any combination thereof.

[0088] Aspect 21. The process defined in any one of aspects 1-20, wherein the oligomerization catalyst system comprises (I) a heteroatomic ligand transition metal compound complex and an organoaluminium compound or a (II) a heteroatomic ligand, a transition metal compound, and an organoaluminium compound.

[0089] Aspect 22. The process defined in any one of aspects 1-21, wherein the oligomer product comprises C6-C30 normal a-olefins, or Ce-Cio normal a-olefins, or 1- hexene and 1 -octene. [0090] Aspect 23. The process defined in any one of aspects 1-22, wherein the oligomer product comprises from 50 to 90 wt. % 1 -hexene and 1 -octene (total).

[0091] Aspect 24. The process defined in any one of aspects 1-23, wherein the ethylene oligomerization reactor comprises a stirred tank reactor, a plug flow reactor, a fixed bed reactor, a continuous stirred tank reactor, a loop reactor, a solution reactor, a tubular reactor, a recycle reactor, or any combination thereof.

[0092] Aspect 25. The process defined any one of aspects 1-24. wherein the ethylene oligomerization conditions comprise an ethylene oligomerization temperature of from 0 to 160 °C and an ethylene oligomerization pressure of from 50 to 3000 psig.

[0093] Aspect 26. The process defined in any one of aspects 1-25, further comprising a step of discharging an effluent stream from the ethylene oligomerization reactor, the effluent stream comprising unreacted ethylene and the oligomer product.

[0094] Aspect 27. The process defined in any one of aspects 1-26, further comprising a step of separating/isolating a 1 -hexene stream, a 1 -octene stream, a 1- decene stream, a 1 -dodecene stream, or any combination thereof, from the oligomer product.

[0095] Aspect 28. The process defined in any one of aspects 1-27, further comprising a step of contacting an oligomerization catalyst composition with a feed stream comprising a Cs to C12 alpha olefin monomer in an oligomerization reactor under oligomerization conditions to produce an oligomerization product comprising oligomers (e g., dimers, trimers, and/or tetramers) of the alpha olefin monomer.

[0096] Aspect 29. The process defined in aspect 28, wherein the feed stream comprises the alpha olefin monomer and from 0.1 to 99 wt. % of the 1 -hexene stream, the 1 -octene stream, the 1 -decene stream, the 1 -dodecene stream, or any combination thereof, defined in aspect 27.

[0097] Aspect 30. The process defined in aspect 28 or 29, wherein the oligomerization catalyst composition comprises a metallocene catalyst system, aZiegler- Natta catalyst system, a chromium catalyst system, a Lewis acid system (e.g., boron trifluoride with a protic promoter), an acid clay, an aluminum halide, a peroxide, an ionic liquid catalyst, or any combination thereof.

[0098] Aspect 31. The process defined in any one of aspects 28-30, wherein the oligomerization product contains dimers, trimers, tetramers, pentamers, hexamers and/or higher oligomers of the alpha olefin monomer. [0099] Aspect 32. The process defined in any one of aspects 28-31, wherein the oligomerization conditions comprise an oligomerization temperature of from 20 to 180 °C.

[0100] Aspect 33. The process defined in any one of aspects 28-32, wherein the oligomerization reactor comprises a stirred tank reactor, a plug flow reactor, a fixed bed reactor, a continuous stirred tank reactor, a loop reactor, a solution reactor, a tubular reactor, a recycle reactor, or any combination thereof.

[0101] Aspect 34. The process defined in any one of aspects 28-33, further comprising a step of discharging an effluent stream from the oligomerization reactor, the effluent stream comprising unreacted alpha olefin monomer and the oligomerization product.

[0102] Aspect 35. The process defined in any one of aspects 28-34, further comprising a step of separating the catalyst composition from the oligomerization product.

[0103] Aspect 36. The process defined in any one of aspects 28-35, further comprising a step of hydrogenating at least a portion of the oligomerization product (e.g.. alpha olefin trimer, a mixture of trimers and tetramers, etc.) to form a polyalphaolefin.

[0104] Aspect 37. The process defined in aspect 36, wherein the hydrogenating is performed at a temperature of from 149 to 316 °C. a pressure of from 300 to 3000 psig, and a liquid hourly space velocity (LHSV) of from 0. 1 h’¹ to 20 h’¹.

[0105] Aspect 38. The process defined in aspect 36 or 37, wherein the hydrogenating is performed in the presence of hydrogen and a metallic hydrogenation catalyst (e.g., cobalt, nickel, palladium, and platinum), which can be supported on a suitable carrier, e.g., alumina, silica gel, silica-alumina composites, silica-coated alumina, zeolites, or combinations thereof.

[0106] Aspect 39. The process defined in any one of aspects 36-38, wherein the polyalphaolefin has a flashpoint greater than or equal to 130 °C, a pour point less than or equal to 20 °C, a kinematic viscosity (KV100) in a range from 1.5 to 300 cSt at 100°C, a viscosity index in a range from 80 to 210, or any combination thereof.

[0107] Aspect 40. The process defined in any one of aspects 36-39, wherein the polyalphaolefin is a circular, bio-circular or a bio- product, wherein the weight or fraction of each circular product attributable to the used oil composition is determined by mass balance attribution and/or the free attribution method. [0108] Aspect 41. The process defined in any one of aspects 36-40, further comprising a step of preparing a product composition comprising the polyalphaolefin.

[0109] Aspect 42. The process defined in aspect 41, wherein the product composition comprises one or more additives and/or one or more base oils.

[0110] Aspect 43. The process defined in aspect 41 or 42, wherein the product composition is used in any suitable application and recycled into the used oil composition.

[0111] Aspect 44. The process defined in any one of aspects 41-43, wherein the product composition is a lubricant oil, a heat transfer fluid, an immersion cooling fluid, or a dielectric fluid.

[0112] Aspect 45. The process defined in any one of aspects 41-44, wherein the product composition contains repeating oligomers and/or polyalphaolefins that can be detected by gas chromatography mass spectrometry (GC-MS) in the product composition and/or in the used oil composition.

Claims

CLAIMS We claim:

1. A process comprising:

(a) providing a used oil composition;

(b) optionally, combining the used oil composition with at least one other liquid, fuel, or oil to produce a feedstock;

(c) introducing the feedstock or the used oil composition into a cracking unit to produce a cracking composition comprising ethylene; and

(d) contacting the ethylene and an ethylene oligomerization catalyst system in an ethylene oligomerization reactor under ethylene oligomerization conditions to produce an oligomer product comprising C4-C30+ normal alpha olefins.

2. The process of claim 1, wherein the used oil composition is recycled from wind turbine lubncants. engine oils, transmission fluids, CVT fluids, axle fluids, industrial gear oils, compressor oils, dielectric fluids, heat transfer fluids, immersion cooling fluids for computers, hydraulic fluids, fiber optic cable filling gels, drilling fluids, oils used in lotions and creams, shampoos, hair care products, greases, gas turbine lubricants, metal-working fluids, textile fluids, bearing oils, bio-based oils, vegetable oils, alpha-olefin waxes, gun oils, or any combination thereof.

3. The process of claim 1 or 2, wherein the used oil composition: is characterized by a KV 100 of from 2 to 150 cSt. a VI of from 80 to 210, a flashpoint greater than or equal to 130 °C, or any combination thereof; contains circular, bio-circular, or bio-polyalphaolefins; contains one or more used Group I-V base stocks; contains less than 1 wt. %, independently, of Ca, Zn, S, and O; or any combination thereof.

4. The process of any one of claims 1-3, wherein the used oil composition is combined with the at least one other liquid, fuel, or oil, which comprises a fossil fuel, a pyrolysis oil. a bio-based liquid, a natural gas liquid, or any combination thereof.

5. The process of any one of claims 1-4, wherein the cracking unit comprises a steam cracker and/or a fluid catalytic cracker.

6. The process of any one of claims 1-5, wherein the process results in a pure component cracking performance increase from 1 to 40%, or from 10 to 40%, and/or results in a blend component cracking performance increase from 0. 1 to 10%, or from 0.2 to 5%, as compared to an otherwise identical feedstock that contains pyrolysis oil instead of the used oil composition.

7. The process of any one of claims 1 -6, wherein fouling in the cracking unit is reduced by from 2 to 60% as compared to an otherwise identical feedstock that contains pyrolysis oil instead of the used oil composition.

8. The process of any one of claims 1-7, wherein step (d) comprises contacting the ethylene, the ethylene oligomerization catalyst system, and an organic reaction medium in the oligomerization reactor, wherein the organic reaction medium comprises a saturated aliphatic hydrocarbon, an aromatic hydrocarbon, a linear a-olefin, or any combination thereof.

9. The process of any one of claims 1-8, wherein the oligomer product comprises C6-C30 normal a-olefins, or C6-C12 normal a-olefins, or 1 -hexene and 1 -octene, or from 50 to 90 wt. % 1 -hexene and 1 -octene.

10. The process of any one of claims 1-9, wherein the process further comprises a step of separating a 1 -hexene stream, a 1 -octene stream, a 1 -decene stream, a 1- dodecene stream, or any combination thereof, from the oligomer product.

11. The process of any one of claims 1-10, wherein the process further comprises a step of contacting an oligomerization catalyst composition with a feed stream comprising a Ce to C12 alpha olefin monomer in an oligomerization reactor under oligomerization conditions to produce an oligomerization product comprising oligomers of the alpha olefin monomer, the oligomers comprising dimers, trimers, and/or tetramers.

12. The process of claim 11, wherein the feed stream comprises the alpha olefin monomer and from 0. 1 to 99 wt. % of the 1 -hexene stream, the 1 -octene stream, the 1- decene stream, the 1 -dodecene stream, or any combination thereof, of claim 10.

13. The process of claim 11 or 12, wherein the oligomerization catalyst composition comprises a metallocene catalyst system, a Ziegler-Natta catalyst system, a chromium catalyst system, a Lewis acid system, an acid clay, an aluminum halide, a peroxide, an ionic liquid catalyst, or any combination thereof.

14. The process of any one of claims 11-13, wherein the process further comprises a step of discharging an effluent stream from the oligomerization reactor and separating unreacted alpha olefin monomer, the oligomerization product, and the catalyst composition.

15. The process of any one of claims 11-14, wherein the process further comprises a step of hydrogenating at least a portion of the oligomerization product to form a polyalphaolefin.

16. The process of claim 15, wherein the hydrogenating is performed in the presence of hydrogen and a metallic hydrogenation catalyst comprising cobalt, nickel, palladium, platinum, or a combination thereof, optionally supported on a solid carrier.

17. The process of claim 15 or 16, wherein the polyalphaolefin has: a flashpoint greater than or equal to 130 °C; a pour point less than or equal to 20 °C; a kinematic viscosity (KV100) in a range from 1.5 to 300 cSt; a viscosity index in a range from 80 to 210; or any combination thereof.

18. The process of any one of claims 15-17, wherein the polyalphaolefin is a circular, bio-circular or a bio- product.

19. The process of any one of claims 15-18. wherein the process further comprises a step of preparing a product composition comprising the polyalphaolefin.

20. The process of claim 19. wherein the product composition: comprises one or more additives and/or one or more base oils; and the product composition is a lubricant oil, a heat transfer fluid, an immersion cooling fluid, or a dielectric fluid.

21. The process of any one of the preceding claims, further comprising a step of certifying any one or more of products produced by the process as circular in accordance with International Sustainability and Carbon Certification (ISCC) standards, based upon a weight or fraction of circular product attributable to pyrolysis oil or plastic waste or the used oil composition determined by mass balance and a free attribution method.