Processes and systems for converting plastic waste and naphtha to olefins

Abstract

Processes and systems for converting plastic waste and naphtha to at least one of ethylene and propylene. The process can include heating the plastic waste to produce a pyoil. The pyoil and the naphtha can be hydrocracked in the presence of molecular hydrogen and a hydrocracking catalyst to produce a hydrocracked product that can include ethane, propane, and aromatics. At least one of ethane and propane can be separated from the hydrocracked product. At least a portion of the ethane, if the ethane is separated from the hydrocracked product, can be converted to ethylene and / or at least a portion of the propane, if the propane is separated from the hydrocracked product, can be converted to propylene.

Description

PROCESSES AND SYSTEMS FOR CONVERTING PLASTIC WASTE AND NAPHTHA TO OLEFINSCROSS-REFERENCED

[0001] This application claims the benefit of U.S. Provisional Application Serial No.63 / 770,747, entitled “Processes and Systems for Converting Plastic Waste and Naphtha to Olefins” filed March 12, 2025, the entirely of which is incorporated by reference herein.FIELD

[0002] This disclosure relates to processes and systems for converting plastic waste and naphtha to olefins. More particularly, such embodiments relate to processes and systems for heating plastic waste to produce a pyoil and hydrocracking the pyoil and naphtha to produce a hydrocracked product that can be converted to one or more olefins.BACKGROUND

[0003] Plastic materials provide environmental benefits, such as reducing the weight of passenger vehicles, e.g., cars and airplanes, to improve fuel economy. Plastic materials have become invaluable in all aspects of life, from healthcare to food production, packaging, and medical equipment. Post-use management of plastic materials is exercised to widely varying degrees throughout the world. One preferred management approach is to collect and recycle post-use plastic waste to reduce the potential of such material to overburden landfills and / or to enter the environment, e.g., river and / or ocean systems.

[0004] Various techniques have been employed to recycle plastic materials, such as mechanical recycling and advanced recycling. In advanced recycling, the plastic waste is broken down to smaller hydrocarbon chains and monomers that can be processed to produce various chemicals such as one or more light olefin monomers. The light olefin yield obtained via the current advanced recycling processes, however, is typically modest, e.g., approximately 45 wt% of light olefins, based on the total weight of the recycled plastic waste.

[0005] There is a need, therefore, for improved processes and systems for recycling plastic materials. This disclosure satisfies this and other needs.SUMMARY

[0006] Processes and systems for converting plastic waste and naphtha to olefins are provided. In some embodiments, a process for converting plastic waste to at least one of ethylene and propylene can include heating the plastic waste to produce a pyoil. The pyoil and naphtha can be hydrocracked in the presence of molecular hydrogen and a hydrocrackingcatalyst to produce a hydrocracked product that can include ethane, propane, and aromatics. At least one of ethane and propane can be separated from the hydrocracked product. At least a portion of the ethane, if the ethane is separated from the hydrocracked product, can be converted to ethylene and / or at least a portion of the propane, if the propane is separated from the hydrocracked product, can be converted to propylene.

[0007] In other embodiments, a process for converting plastic waste to at least one of ethylene and propylene can include heating the plastic waste to a temperature of up to 550°C to produce a pyoil. The pyoil and naphtha can be hydrocracked in the presence of molecular hydrogen and a hydrocracking catalyst at a molecular hydrogen partial pressure in a range from 0.1 MPa-g to 5 MPa-g and at a temperature in a range from 350°C to 600°C to produce a hydrocracked product. The hydrocracking catalyst can include Pt / ZSM-5, Pt-Ir / ZSM-5, PtSn / ZSM-5, Pt-Ru / ZSM-5, Pt-Rh / ZSM-5, Pt / MOR, Pt / FAU, Pt / BEA, Ni / ZSM-5, or a mixture thereof. The hydrocracked product can include at least 30 wt% of ethane, at least 10 wt% of propane and less than 20 wt% of aromatics.

[0008] In some embodiments, a system for converting plastic waste and naphtha to at least one of ethylene and propylene, can include a pyrolysis furnace, a hydrocracker, a fractionation unit, and at least one of a steam cracker and a catalytic dehydrogenation reactor. The pyrolysis furnace can be configured to heat the plastic waste to produce a pyoil. The hydrocracker can be configured to hydrocrack at least a portion of the pyoil and the naphtha in the presence of molecular hydrogen and a hydrocracking catalyst to produce a hydrocracked product comprising ethane, propane, and aromatics. The fractionation unit can be configured to separate at least one of the ethane and the propane from the hydrocracked product. The steam cracker, if present, can be configured to convert at least a portion of the ethane, if the ethane is separated from the hydrocracked product, to ethylene. The catalytic dehydrogenation reactor, if present, can be configured to convert at least a portion of the propane, if the propane is separated from the hydrocracked product, to propylene.BRIEF DESCRIPTION OF THE DRAWINGS

[0009] The Figure depicts an illustrative system for converting plastic waste and naphtha to at least one of ethylene and propylene, according to one or more embodiments described.DETAILED DESCRIPTION

[0010] Various specific embodiments, versions and examples of the invention will now be described, including preferred embodiments and definitions that are adopted herein for purposes of understanding the claimed invention. While the following detailed descriptiongives specific preferred embodiments, those skilled in the art will appreciate that these embodiments are exemplary only, and that the invention may be practiced in other ways. For purposes of determining infringement, the scope of the invention will refer to any one or more of the appended claims, including their equivalents, and elements or limitations that are equivalent to those that are recited. Any reference to the “invention” may refer to one or more, but not necessarily all, of the inventions defined by the claims.

[0011] In this disclosure, a process is described as comprising at least one “step.” It should be understood that each step is an action or operation that may be carried out once or multiple times in the process, in a continuous or discontinuous fashion. Unless specified to the contrary or the context clearly indicates otherwise, multiple steps in a process may be conducted sequentially in the order as they are listed, with or without overlapping with one or more other steps, or in any other order, as the case may be. In addition, one or more or even all steps may be conducted simultaneously with regard to the same or different batch of material. For example, in a continuous process, while a first step in a process is being conducted with respect to a raw material just fed into the beginning of the process, a second step may be carried out simultaneously with respect to an intermediate material resulting from treating the raw materials fed into the process at an earlier time in the first step. Preferably, the steps are conducted in the order described.

[0012] Unless otherwise indicated, all numbers indicating quantities in this disclosure are to be understood as being modified by the term “about” in all instances. It should also be understood that the precise numerical values used in the specification and claims constitute specific embodiments. Efforts have been made to ensure the accuracy of the data in the examples. However, it should be understood that any measured data inherently contains a certain level of error due to the limitation of the technique and / or equipment used for acquiring the measurement.

[0013] Certain embodiments and features are described herein using a set of numerical upper limits and a set of numerical lower limits. It should be appreciated that ranges including the combination of any two values, e.g., the combination of any lower value with any upper value, the combination of any two lower values, and / or the combination of any two upper values are contemplated unless otherwise indicated.

[0014] The indefinite article “a” or “an”, as used herein, means “at least one” unless specified to the contrary or the context clearly indicates otherwise. Thus, embodiments using “a reactor” or “a conversion zone” include embodiments where one or two or more reactors orconversion zones are used, unless specified to the contrary or the context clearly indicates that only one reactor or conversion zone is used.

[0015] In this disclosure, “A, B, ... or a combination thereof’ means “A, B, ... or any combination of any two or more of A, B, ... ” and “A, B, ... , or a mixture thereof’ means “A, B, ... , or any mixture of any two or more of A, B, ... ”.

[0016] The term “hydrocarbon” means (i) any compound consisting of hydrogen and carbon atoms or (ii) any mixture of two or more such compounds in (i). The term “Cn hydrocarbon,” where n is a positive integer, means (i) any hydrocarbon compound comprising carbon atom(s) in its molecule at the total number of n, or (ii) any mixture of two or more such hydrocarbon compounds in (i). Thus, a C2 hydrocarbon can be ethane, ethylene, acetylene, or mixtures of at least two of these compounds at any proportion. A “Cm to Cn hydrocarbon” or “Cm-Cn hydrocarbon,” where m and n are positive integers and m < n, means any of Cm, Cm+1, Cm+2, ..., Cn-1, Cn hydrocarbons, or any mixtures of two or more thereof. Thus, a “C2 to C3 hydrocarbon” or “C2-C3 hydrocarbon” can be any of ethane, ethylene, acetylene, propane, propene, propyne, propadiene, cyclopropane, and any mixtures of two or more thereof at any proportion between and among the components. A “saturated C2-C3 hydrocarbon” can be ethane, propane, cyclopropane, or any mixture thereof of two or more thereof at any proportion. A “Cn+ hydrocarbon” means (i) any hydrocarbon compound comprising carbon atom(s) in its molecule at the total number of at least n, or (ii) any mixture of two or more such hydrocarbon compounds in (i). A “Cn- hydrocarbon” means (i) any hydrocarbon compound comprising carbon atoms in its molecule at the total number of at most n, or (ii) any mixture of two or more such hydrocarbon compounds in (i). A “Cm hydrocarbon stream” means a hydrocarbon stream consisting essentially of Cm hydrocarbon(s). A “Cm-Cn hydrocarbon stream” means a hydrocarbon stream consisting essentially of Cm-Cn hydrocarbon(s).

[0017] A "polymer" has two or more of the same or different repeating units / mer units or simply units. A "homopolymer" is a polymer having repeating units that are the same. A "copolymer" is a polymer having two or more repeating units that are different from each other. As such, the term “copolymer” includes terpolymers (a polymer having three units that are different from each other), tetrapolymers (a polymer having four units that are different from each other), and so on. The term "different" as used to refer to units indicates that the units differ from each other by at least one atom and / or are different isomerically. The polymer can be naturally occurring, modified naturally occurring, and / or synthetic.

[0018] In some embodiments, the polymer can be or can include, but is not limited to, a nitrogen-containing polymer, a chlorine-containing polymer, a bromine-containing polymer, afluorine-containing polymer, an oxygen-containing polymer, or a mixture thereof. In some embodiments, the polymer can be or can include, but is not limited to, one or more polyethylene polymers (“PE”), one or more polypropylene polymers (“PP”), one or more polystyrene polymers (“PS”), one or more butadiene polymers, one or more isoprene polymers, one or more isobutylene polymers, one or more polyethylene terephthalate polymers (“PET”), one or more ethylene vinyl acetate polymers, one or more polycarbonate polymers (“PC”), one or more polylactic acid polymers, one or more acrylate polymers, one or more polyoxymethylene polymers, one or more polyester polymers (“PES”), one or more polyoxybenzylmethylenglycolanhydride polymers, one or more polyepoxide polymers, one or more polyamide polymers, e.g., nylon and / or aromatic polyamide; one or more polynitrile polymers, e.g., poly(acrylonitrile) and / or poly(methacrylonitrile); one or more polyurethane polymers (“PU”), one or more polyvinyl chloride polymers (“PVC”), one or more polyvinylidene chloride polymers (“PVDC”), one or more polylactic acid polymers (“PLA”), one or more acrylic polymers, e.g., poly(methyl methacrylate), one or more acetal polymers, e.g., polyoxymethylene, one or more acrylonitrile-butadiene-styrene polymers (“ABS”), or a mixture thereof.

[0019] As used herein, the term “polyolefin” refers to and includes high-density polyethylene (“HDPE”), low-density polyethylene (“LDPE”), linear low-density polyethylene (“LLDPE”), polyethylene (“PE”), and polypropylene (“PP”), or mixtures thereof. The term “polyolefin” also includes co-polymers of various olefins, such as butene, hexenes, and / or any other olefins suitable for polymerization.

[0020] The term “plastic waste” refers to a composition that includes one or more polymers. The plastic waste can be or can include, but is not limited to, any classification of consumer waste plastics, post-consumer wastes, and post-industrial wastes. Preferably, the plastic waste comprises, consists essentially of, or consists of a synthetic polymer. Preferably, the plastic waste comprises, consists essentially of, or consists of a used polymer. Preferably, the plastic waste comprises, consists essentially of, or consists of one or more polymers derived from one or more olefin monomers (e.g., polyethylene, polypropylene, ethylene-propylene co-polymer, polystyrene, and the like).

[0021] It is noted that some types of plastic waste can also include bio-derived components. For example, some types of plastic waste can include biogenic waste in the form of paper compounds. In some embodiments, 1 wt% to 25 wt% of the plastic waste can correspond to bio-derived material. Such bio-derived material can also potentially contribute to the nitrogen content of plastic waste. The plastic waste, in addition to the one or more polymers, can alsoinclude any additives, modifiers, packaging dyes, and / or other components typically added to a polymer during and / or after formulation. The plastic waste can also further include any components typically found in polymer waste.

[0022] The terms “liquid plastic waste” and “pyoil” are used interchangeably herein and refer to a hydrocarbon product that is at least partially obtained from the pyrolysis of one or more polymers, preferably from the pyrolysis of plastic waste. In the pyrolysis process, the polymer(s) is / are depolymerized via pyrolysis conditions. It will be understood by the skilled person that the liquid plastic waste or pyoil contains hydrocarbons, but can additionally contain non-hydrocarbon components, such as halogenated compounds, oxygenates, nitrogenates, and the like. Generally, the pyoil contains at least 90 wt% of hydrocarbons, preferably at least 95 wt% of hydrocarbons.

[0023] The term "naphtha" refers to the middle boiling range hydrocarbon fraction or fractions that are major components of gasoline, while the term "FCC naphtha" refers to preferred naphtha that has been produced by the well-known process of fluid catalytic cracking. Naphthas that have a middle boiling range are those having a boiling point in a range from 10°C (i.e., from about C5 hydrocarbons) to 232°C at atmospheric pressure, preferably from 21°C to 221°C. True boiling point distributions (the distribution at atmospheric pressure) can be measured according to ASTM D2887-24. Producing naphtha in an FCC process without added hydrogen results in a naphtha that is relatively high in olefins and aromatics. Other naphthas such as steam cracked naphthas and coker naphthas may also contain relatively high concentrations of olefins. Typical olefinic naphthas have olefin contents of at least 5 wt% up to 60 wt%, based on the weight of the naphtha, preferably 5 wt% to 40 wt%; sulfur contents from 300 ppmw to 7,000 ppmw, based on the weight of the naphtha; and nitrogen contents from 5 ppmw to 500 ppmw, based on the weight of the naphtha. The olefins in naphtha include open chain olefins, cyclic olefins, dienes, and cyclic hydrocarbons with olefinic side chains. Because olefins and aromatics are high octane number components, olefinic naphtha generally exhibits higher research and motor octane values than does hydrocracked naphtha. While olefinic naphthas are typically high in olefin content, they may also contain other compounds, especially sulfur-containing and nitrogen-containing compounds.

[0024] For the purposes of this disclosure, the nomenclature of elements is pursuant to the version of the Periodic Table of Elements (under the new notation) as provided in Hawley's Condensed Chemical Dictionary, 16thEd., John Wiley & Sons, Inc., (2016), Appendix V. For example, a Group 6 element includes Cr, a Group 7 element includes Mn, a Group 8 element includes Fe, a Group 9 element includes Co, and a group 10 element includes Ni.

[0025] The term “alkane” means a saturated hydrocarbon. The term “cyclic alkane” means a saturated hydrocarbon comprising a cyclic carbon ring in the molecular structure thereof. An alkane can be linear, branched, or cyclic.

[0026] The term “aromatics” is to be understood in accordance with its art-recognized scope, which includes alkyl substituted and unsubstituted mono- and polynuclear compounds.Process Overview

[0027] Described herein are processes and systems that improve the yield of light olefins. In the present processes, it has been discovered that hydrocracking liquid plastic waste / pyoil and naphtha can increase light alkane yields, e.g., ethane and propane, which can be converted to more valuable olefins, i.e., ethylene and / or propylene.

[0028] The process for converting plastic waste and naphtha to ethylene and propylene can include heating the plastic waste to produce the pyoil. The plastic waste can be heated at a temperature in a range from 225°C to 575°C to produce the pyoil. In some embodiments, the plastic waste can be heated under pyrolysis conditions, i.e., in the absence or substantial absence of molecular oxygen. In some embodiments, the pyoil can be produced by heating the plastic waste in a pyrolysis reactor.

[0029] As noted above, the plastic waste is a composition that includes one or more polymers. In some embodiments, the plastic waste can be or can include, but is not limited to, a polyethylene, a polypropylene, a polystyrene, a polyethylene terephthalate), a poly(vinyl chloride), a poly(vinyl dichloride), a polyamide, a polynitrile, a polyurethane, a polycarbonate, a polylactic acid, an acrylic, an acetal, an acrylonitrile-butadiene-styrene, a polyester, a polyepoxide, a polyoxybenzylmethylenglycolanhydride, or a mixture thereof.

[0030] The pyoil and the naphtha can be hydrocracked in the presence of molecular hydrogen and a hydrocracking catalyst to produce a hydrocracked product that can include ethane, propane, butanes, pentanes, aromatics, or a mixture thereof. The hydrocracking can be carried out in a hydrocracking reactor. In some embodiments, the pyoil and the naphtha can be mixed and introduced as a mixture into the hydrocracking reactor. In other embodiments, the pyoil and the naphtha can be introduced separately into the hydrocracking reactor and mixed therein. Surprisingly and unexpectedly it was discovered that converting pyoil and naphtha together via hydrocracking increases the total yield to ethane and propane and reduces the total yield to benzene, toluene, and xylenes (BTX), as compared to what was expected from the weighted average of hydrocracking pyoil or naphtha alone. These surprising and unexpected results point to benefits of co-processing pyoil and naphtha via hydrocracking.

[0031] In some embodiments, the pyoil, prior to hydrocracking with the naphtha, can optionally be hydrotreated in the presence of a hydrotreating catalyst to remove at least a portion of any halogen(s), oxygen, and / or nitrogen from the pyoil.

[0032] In some embodiments, ethane can be separated from the hydrocracked product and converted to ethylene. In some embodiments, propane can be separated from the hydrocracked product and converted to propylene. In some embodiments, ethane and propane can be separated from the hydrocracked product and converted to ethylene and propylene, respectively. In some embodiments, the ethane can be converted to ethylene via steam cracking or other dehydrogenation processes. In some embodiments, the propane can be converted to propylene via a dehydrogenation process. In some embodiments, the process can include at least one of steam cracking the ethane to produce ethylene and catalytically dehydrogenating the propane to produce propylene.

[0033] In some embodiments, an aromatic product can be separated from the hydrocracked product. In such embodiments, at least a portion of the aromatic product can be saturated in the presence of molecular hydrogen and a saturating catalyst to produce a saturated product. The saturated product or at least a portion thereof can be recycled and combined with an additional quantity of the pyoil and an additional quantity of the naphtha to produce additional hydrocracked product via hydrocracking. In some embodiments, the aromatic product can also include one or more butanes, pentanes and the one or more butanes, pentanes can be present in the saturated product when the saturated product is combined with the additional quantity of the pyoil and the additional quantity of naphtha.Preparation of Plastic Waste

[0034] Consumer waste plastics or “plastic waste” are classified and include polyethylene terephthalate waste (plastics recycle classification type 1), high density polyethylene waste (plastics recycle classification type 2), polyvinyl chloride waste (plastics recycle classification type 3), low density polyethylene waste (plastics recycle classification type 4), polypropylene waste (plastics recycle classification type 5), polystyrene waste (plastics recycle classification type 6), and other polymer waste (plastics recycle classification type 7). In recycling plastic waste, polyethylene waste and polypropylene waste are often individually sorted from the plastic waste and sometimes sorted together from the plastic waste. Undesirable plastic materials such as multilayer films or composites and / or compounded wastes such as rubber tires can be mechanically sorted from the feed stream with near infrared spectroscopy (NIR), laser, or x-ray technologies. Other undesirable materials can include stones, metals and othernon-combustible hard materials which can be removed by mechanical means. For example, ferrous metals can be removed by a magnet.

[0035] In some embodiments, to prepare plastic particles, the solid polymers can be crushed, chopped, ground, or otherwise physically processed to reduce the median particle size to 3.0 cm or less, or 2.5 cm or less, or 2.0 cm or less, or 1.0 cm or less, such as down to 0.01 cm or possibly still smaller. For determining a median particle size, the particle size is defined as the diameter of the smallest bounding sphere that contains the particle.Pyrolysis of Plastic Waste

[0036] In the present processes, a feed stream of a plastic waste (sometimes referred to as “plastic feedstock”) can be heated to a temperature that produces the pyoil. In some embodiments, the plastic waste can be heated at a temperature in a range from 225°C, 250°C, 275°C, or 300°C to 350°C, 400°C, 450°C, 500°C, 550°C, or 575°C to produce the pyoil.

[0037] In some embodiments, the plastic waste can be heated under pyrolysis conditions that can be carried out in the presence of little to no molecular oxygen, i.e., oxygen that is not covalently bonded and part of the plastic waste. If molecular oxygen is present, it can be present in an amount less than the stoichiometric amount required for complete combustion. In some embodiments, pyrolysis of the plastic waste can be carried out in an environment, e.g., in a pyrolysis reactor, having an oxygen content of less than 40%, less than 30%, less than 20%, less than 10%, less than 5%, less than 1%, less than 0.5%, or less than 0.01% of the stoichiometric amount of oxygen required for complete combustion of the plastic waste. In other embodiments, pyrolysis of the plastic waste can be carried out in the absence of any added oxygen, in which case molecular oxygen may be present in trace amounts, but no oxygen is deliberately added.

[0038] In some embodiments, the plastic waste can be pyrolyzed using one or more of various pyrolysis methods including, but not limited to, fast pyrolysis and other pyrolysis methods such as vacuum pyrolysis, slow pyrolysis, and the like. Fast pyrolysis is an intense, short duration process that can be carried out in a variety of pyrolysis reactors such as fixed bed pyrolysis reactors, fluidized bed pyrolysis reactors, circulating fluidized bed reactors, or other pyrolysis reactors capable of fast pyrolysis. Fast pyrolysis includes rapidly imparting a relatively high temperature to feedstocks for a very short residence time, typically about 0.5 seconds to about 30 seconds, to produce a pyrolysis effluent and then rapidly reducing the temperature of the pyrolysis effluent before chemical equilibrium can occur. By this approach, the structures of polymers are broken into reactive chemical fragments that are initially formedby depolymerization and volatilization reactions, but do not persist for any significant length of time.

[0039] The heating and cooling of products produced in a plastic waste reactor (a reactor sometimes referred to as a “pyrolyzer” or a “pyrolysis unit”) can be performed in any convenient manner. For example, at least a portion of the heating of the plastic waste to the pyrolysis temperature can be performed at a heating rate of 100°C per second or more, or 200°C per second or more, such as up to l,000°C per second or even faster. Suitable fast pyrolysis processes can include those described in WO Publication No.: WO2020 / 252228 and U.S. Patent Application Publication No.: 2021 / 0130700.

[0040] Both operating temperature of the pyrolysis unit and reaction time can depend, at least in part, on the desired products. Shorter reaction times (at or above 500°C) can reduce or minimize the formation of coke. In some embodiments, the reaction time can be in a range from 0.1 seconds, 0.3 seconds, 0.5 seconds, or 1 second to 2 seconds, 3 seconds, 4 seconds, 5 seconds, or 6 seconds. In some embodiments, a diluent steam can be fed into the pyrolysis reactor. The diluent steam can also serve as a fluidizing gas. In some embodiments, a weight ratio of the diluent steam to plastic waste fed into the pyrolysis reactor can be in a range from 0.3:1 to 10:1.

[0041] In some embodiments, the plastic waste can be fed into the pyrolysis unit and heated to a temperature in a range from 250°C and 500°C for a given reaction time. In some embodiments, the pyrolysis unit can melt the plastic waste in a fluidized flow or in a transport or pneumatic conveyance flow, with a dilute phase of heat carrier particles. A quasi-dense bed of plastic and heat carrier particles undergo pyrolysis at the bottom of the plastic waste reactor. Gaseous pyrolyzed plastic and heat carrier particles flow upwardly upon size reduction due to pyrolysis. Alternatively, the pyrolysis unit can be a continuous stirred tank reactor, a rotary kiln, or an auger reactor. In some embodiments, the pyrolysis unit can employ an agitator.

[0042] The pyoil can optionally be cooled to a temperature of less than 500°C at the end of the reaction time. An effluent stream from the pyrolysis unit typically includes the heat carrier particles, the diluent gas stream, a pyrolyzed product, and other products such as olefin and oil. Most notably, simpler lighter hydrocarbon molecules, including ethylene and propylene, can be generated at varying fractions within the effluent stream.

[0043] In some embodiments, the pyrolysis unit can be a fluidized bed where the plastic waste can be mixed with heated fluidized particles. Sand is an example of a suitable type of fluidizing particle for the fluidized bed. During operation, sand (or another type of heat transfer particle) can be passed into a regenerator to bum off coke and heat the particles. Oftenadditional heat is supplied in the regenerator to compensate for the coke in the process. Typically, the heated particles are mixed with the plastic waste prior to entering the reactor. By heating the heat transfer particles to a temperature above the desired pyrolysis temperature, the heat transfer particles can provide at least a portion of the heat needed to achieve the pyrolysis temperature. For example, the heat transfer particles can be heated to a temperature that is greater than the desired pyrolysis temperature by 100°C or more. Optionally, if the plastic feedstock, sand, and fluidizing steam do not provide sufficient material to form a fluidized bed, additional fluidizing gas can be added, such as nitrogen.

[0044] Upon exiting from the pyrolysis unit, the heat transfer particles can be separated from the vapor portions of the effluent using a cyclone or another solid / vapor separator. Such a separator can also remove any other solids present after pyrolysis. Optionally, in addition to a cyclone or other primary solid / vapor separator, one or more filters can be included at a location downstream from the cyclone to allow for removal of fine particles that become entrained.

[0045] Heating the plastic waste to produce the pyoil can remove a relatively significant amount of contaminants that can be present in the plastic waste. In some embodiments, pyrolyzing the plastic waste can remove a significant amount of halogen(s), oxygen, and / or nitrogen therefrom. As such, the pyoil obtained from the pyrolysis unit can contain a reduced amount of halogen(s), oxygen, and / or nitrogen as compared to the plastic waste prior to pyrolyzing the pyoil.Hydrocracking Pyoil and Naphtha

[0046] Hydrocracking can be used to upgrade hydrocarbon feedstocks by adding hydrogen, removing impurities, and cracking hydrocarbons to a desired boiling range. Hydrocracking produces a hydrocracked product that has a lower molecular weight than the hydrocarbon feedstock. Hydrocracking requires conversion of a variety of types of molecules. Exemplary hydrocracking processing include those described in U.S. Patent Nos.: 8,932,454; and.9,309,472.

[0047] The hydrocracking of the pyoil, the naphtha, and optionally at least a portion of the saturated product can be carried out at a variety of conditions depending on many factors such as type of feed, desired cycle length, and expected product slate. The hydrocracking can be carried out at a molecular hydrogen partial pressure in a range from 0.1 MPa-g, 1 MPa-g, 3 MPa-g, or 5 MPa-g to 7 MPa-g, 8 MPa-g, 9 MPa-g, or 10 MPa-g. The hydrocracking can be carried out at a temperature in a range from 325°C, 350°C, 375°C, 400°C, or 425°C to 475°C, 500°C, 550°C, 600°C, or 625°C. The hydrocracking can be carried out at a liquid hourly spacevelocity in a range from 0.05 g, 0.1 g, 1 g, 3 g, or 5 g to 7 g, 9g, 10 g, or 12 g feed / g catalyst / hour. In some embodiments, the hydrocracking can be carried out at a molecular hydrogen partial pressure in a range from 0.1 MPa-g to 10 MPa-g, at a temperature in a range from 350°C to 600°C, and at a liquid hourly space velocity in a range from 0.1 g and 10 g feed / g catalyst / hour.

[0048] In some embodiments, the mixture of the pyoil and the naphtha can contain a greater amount of pyoil than the naphtha. In other embodiments, the mixture of the pyoil and the naphtha can contain a greater amount of the naphtha than the pyoil. In some embodiments, a weight ratio of the pyoil to the naphtha can be in a range from 0.01:1 to 100:1, 0.1:1 to 10:1, 1:1 to 5:1, 1:1.5 to 3:l, or 1:2 to 2.5:1

[0049] In some embodiments, the plastic waste can be blended or otherwise mixed with a carrier fluid to produce a mixed feed containing the plastic waste and the carrier fluid. In some embodiments, the carrier fluid can be or can include, but is not limited to, a wide range of petroleum or petrochemical products or streams, e.g., hydrocarbon products and / or intermediate streams produced from petroleum processing such as distillation, steam cracking, catalytic cracking, refining, and the like. In some embodiments, the naphtha or at least a portion of the naphtha that can ultimately be introduced into the hydrocracker can be utilized as the carrier fluid.

[0050] In some embodiments, the hydrocracked product can include at least 10 wt%, at least 15 wt%, at least 20 wt%, at least 25 wt%, at least 30 wt%, at least 35 wt%, at least 40 wt%, at least 45 wt%, or at least 50 wt% of ethane, based on the total weight of the hydrocracked product. In some embodiments, the hydrocracked product can include at least 10 wt%, at least 15 wt%, at least 20 wt%, at least 25 wt%, at least 30 wt%, at least 35 wt%, at least 40 wt%, at least 45 wt%, or at least 50 wt% of propane, based on the total weight of the hydrocracked product. In some embodiments, the hydrocracked product can include less than 40 wt%, less than 35 wt%, less than 30 wt%, less than 25 wt%, less than 20 wt%, less than 15 wt%, less than 10 wt%, or less than 5 wt% of aromatics, based on the total weight of the hydrocracked product. In some embodiments, the hydrocracked product can include at least 10 wt% of ethane, at least 10 wt% of propane, and less than 40 wt% of aromatics, based on the total weight of the hydrocracked product.

[0051] In some embodiments, the hydrocracked product can include ethane in an amount from 5 wt%, 10 wt%, 15 wt%, 20 wt%, 25 wt%, or 45 wt% to 55 wt%, 65 wt%, 75 wt%, 85 wt%, or 95 wt%, propane in an amount from 5 wt%, 10 wt%, 15 wt%, 20 wt%, 25 wt%, or 45 wt% to 55 wt%, 65 wt%, 75 wt%, 85 wt%, or 95 wt%, and aromatics in an amount from 0.5wt%, 1 wt%, 3 wt%, 5 wt%, or 7 wt% to 10 wt%, 15 wt%, 20 wt%, 25 wt%, 30 wt%, 35 wt%, or 40 wt%, based on the total weight of the hydrocracked product.

[0052] In some embodiments, the hydrocracked product can include 50 wt%, 55 wt%, 60 wt%, or 65 wt% to 70 wt%, 75 wt%, 80 wt%, 85 wt%, or 90 wt% of a combined amount of ethane and propane and less than 40 wt%, less than 35 wt%, less than 30 wt%, less than 25 wt%, less than 20 wt%, less than 15 wt%, less than 10 wt%, or less than 5 wt% of aromatics, based on the total weight of the hydrocracked product. In some embodiments, the hydrocracked product can include 60 wt%, 65 wt%, 70 wt%, 75 wt%, or 80 wt% to 85 wt%, or 90 wt% of a combined amount of ethane and propane and less than 15 wt%, less than 10 wt% or less than 5 wt% of aromatics, based on the total weight of the hydrocracked product. In some embodiments, the hydrocracked product can include 50 wt%, 55 wt%, 60 wt%, or 65 wt% to 70 wt%, 75 wt%, 80 wt%, 85 wt%, or 90 wt% of a combined amount of ethane and propane and less than 20 wt%, less than 17 wt%, less than 15 wt%, less than 10 wt%, less than 7 wt%, or less than 5 wt% of a combined amount of butanes and pentanes, based on the total weight of the hydrocracked product.

[0053] Surprisingly and unexpectedly, it was discovered that by co-processing pyoil and naphtha via hydrocracking, the total yield to ethane and propane can be increased by at least 2%, at least 3%, at least 4%, at least 5%, or at least 6%, as compared to what was expected from the weighted average of hydrocracking pyoil or naphtha alone. In addition, surprisingly and unexpectedly it was discovered that by co-processing pyoil and naphtha via hydrocracking, the total yield of BTX can be reduced by at least 3%, at least 4%, at least 5%, at least 10%, at least 15%, at least 20%, at least 25%, or more, as compared to what was expected from the weighted average of hydrocracking pyoil or naphtha alone.

[0054] The hydrocracking catalyst can include a metal function and an acid function. The acid function can be or can include, but is not limited to, a zeolite. In some embodiments, the metal function can be or can include, but is not limited to, Ni, Pt, Pd, Co, Rh, Ir, Ru, Re, In, Sn, Zn, a mixture thereof, or a combination thereof. In at least one embodiment, the metal function can be Pt. In some embodiments, the hydrocracking catalyst can include 0.01 wt%, 0.05 wt%, 0.07 wt%, 0.1 wt%, 0.2 wt%, 0.3 wt%, 0.4 wt%, 0.5 wt%, 0.6 wt%, 0.7 wt%, or 1 wt% to 3 wt%, 5 wt%, 10 wt%, 15 wt%, 20 wt%, 25 wt%, or 30 wt% of the metal function, based on the total weight of the hydrocracking catalyst.

[0055] In some embodiments, the acid function can be or can include a zeolite. In some embodiments, the zeolite can be or can include, but is not limited to, zeolite Beta, zeolite X, zeolite Y, faujasite, ultrastable Y (USY), dealuminized Y (Deal Y), Mordenite, ZSM-3, ZSM-4, ZSM-18, ZSM-20, ZSM-48, and combinations thereof, which zeolite can be loaded with one or more active metals. In some embodiments, the active metal(s) can be or can include, but are not limited to, one or more Group 8 - 10 noble metal such as platinum and / or palladium, one or more a Group 8 - 10 non-noble metal such nickel, cobalt, and / or iron, mixtures thereof, or combinations thereof, and optionally a Group 6 metal such as molybdenum and / or tungsten. Zeolite materials include materials having a recognized zeolite framework structure, such as framework structures recognized by the International Zeolite Association. Such zeolite materials can correspond to silicoaluminates, silicoaluminophosphates, aluminophosphates, and / or other combinations of atoms that are used to form a zeolite framework structure.

[0056] Zeolites can be classified as having small, medium, large, and extra-large pore structures for pore windows delimited by 8, 10, 12, and more than 12 T-atoms, respectively. Extra-large pore zeolites (>12R) include, for example, AET (14R, e.g., ALPO-8), SFN (14R, e.g., SSZ-59), VFI (18R, e.g., VPI-5), CLO (20R, e.g., cloverite), and ITV (30R, e.g., ITQ-37) framework type zeolites. Extra-large pore zeolites generally have a free pore diameter of larger than about 0.8 nm. Large pore zeolites (12R) include, for example, LTL, MAZ, FAU, EMT, OFF, MTW, *BEA, MOR, and SFS framework type zeolites, e.g., mazzite, offretite, zeolite L, zeolite Y, zeolite X, omega, ZSM-2, ZSM-12, zeolite T, Beta, and SSZ-56. Large pore zeolites generally have a free pore diameter of 0.6 nm to 0.8 nm. Medium (or intermediate) pore size zeolites (10R) include, for example, MFI, MEL, *MRE, EUO, MTT, MFS, AEL, AFO, HEU, FER, MWW, and TON framework type zeolites. In some embodiments, the medium (or intermediate) pore size zeolites can be ZSM-5, ZSM-11, ZSM-48, ZSM-22, ZSM-23, ZSM-35, MCM-22, MCM-49, silicalite- 1 , silicalite-2, or a mixture thereof. Medium pore size zeolites generally have a free pore diameter of 0.45 nm to 0.6 nm. Small pore size zeolites (8R) include, for example, CHA, SSZ-13, RTH, ERI, KFI, LEV, and LTA framework type zeolites. In some embodiments, the small pore size zeolites can be ZK-4, SAPO-34, SAPO-18, SAPO-35, ZK-14, SAPO-42, ZK-21, ZK-22, ZK-5, ZK-20, or a mixture thereof.

[0057] In addition to or in lieu of zeolite materials, other types of crystalline acidic support materials can also be suitable. Optionally, a zeolite material and / or other crystalline acidic material can be mixed or bound with other metal oxides such as alumina, titania, and / or silica. In some embodiments, acidic, non-zeolite materials such as metal-organic frameworks (MOF), zeolitic imidazolate frameworks (ZIF) can also be suitable as the support. Some hydrocracking catalysts are described in U.S. Patent Application Publication No.: 2024 / 0368484.

[0058] Acidity of a catalyst can be measured by a number of known methods. A nonlimiting example of a parameter for inferring acidity is the cracking and isomerization tendencyof a catalyst by the Alpha value test. The Alpha value test is a measure of the cracking activity of a catalyst and is described in US Pat. No. 3,354,078 and in the Journal of Catalysis, NA, p.527 (1965); v.6, p. 278 (1966); and v.61, p. 395 (1980). The experimental conditions of the test referenced herein include a constant temperature of 538°C and a variable flow rate as described in detail in the Journal of Catalysis, v.61, p. 395. The “Alpha Value” is the cracking rate of a feed in reference to a standard sample of silica alumina. Catalysts suitable for hydrocracking activity can have Alpha values of at least 25, or at least 50, or at least 100. Such catalysts can include amorphous catalysts, such as amorphous silica-alumina or alumina supports or additives and / or zeolites.

[0059] In some embodiments, the hydrocracking catalyst can contain one or more sulfided base metals on acidic supports, such as amorphous silica alumina, zeolites, or other cracking molecular sieves such as USY, or acidified alumina. In some embodiments, the hydrocracking catalyst can include at least one molecular sieve, such as a zeolite. Often these acidic supports are mixed or bound with other metal oxides such as alumina, titania or silica. Non-limiting examples of supported catalytic metals for hydrocracking catalysts can be or can include, but are not limited to, nickel, nickel-cobalt-molybdenum, cobalt-molybdenum, nickel-tungsten, nickel-molybdenum, and / or nickel-molybdenum-tungsten. Additionally or alternatively, hydrocracking catalysts with noble metals can also be used. Non-limiting examples of noble metals include those based on platinum and / or palladium. Support materials which may be used for both the noble and non-noble metal catalysts can include a refractory oxide material such as alumina, silica, alumina-silica, kieselguhr, diatomaceous earth, magnesia, zirconia, or combinations thereof, with alumina, silica, alumina-silica being the most common.

[0060] As described above, the hydrocracking catalyst can include a large pore molecular sieve that is selective for cracking branched hydrocarbons and / or cyclic hydrocarbons. Zeolite Y, such as ultrastable zeolite Y (USY) is an example of a zeolite molecular sieve that is selective for cracking of branched hydrocarbons and cyclic hydrocarbons. The silica to alumina ratio in a USY zeolite can be at least about 10, such as at least about 15, or at least about 25, or at least about 50, or at least about 100. The unit cell size for a USY zeolite can be about 24.50 Angstroms or less, such as about 24.45 Angstroms or less, or about 24.40 Angstroms or less, or about 24.35 Angstroms or less, such as about 24.30 Angstroms. Some suitable hydrocracking catalysts include those described in U.S. Patent Nos.: 8,932,454; and 9,309,472.

[0061] In the present process, the pyoil, the naphtha, and optionally at least a portion of the saturated product can be hydrocracked in the presence of molecular hydrogen and thehydrocracking catalyst. In some embodiments, the metal function can be or can include, but is not limited to, Ni, Pt, Pd, Co, Rh, Ir, Ru, Re, In, Sn, Zn, a mixture thereof, or a combination thereof, and the acid function can be or can include, but is not limited to, a zeolite selected from MFI, MOR, FAU, MWW, BEA, or a mixture thereof. In some embodiments, the hydrocracking catalyst can be or can include, but is not limited to, Ni / MFI, Ni / MOR, Ni / FAU, Ni / BEA, Pt / MFI, Pt / MOR, Pt / FAU, Pt / BEA, Pt-Ir / MFI, Pt-Re / MFI, Pt-Ru / MFI, or a mixture thereof. In at least one embodiment, the hydrocracking catalyst can be or can include Pt / MFI that contains Pt in an amount from 0.3 wt%, or 0.5 wt% to 0.6 wt%, 0.7 wt%, 1 wt%, 1.5 wt%, or 2 wt%, based on the total weight of the catalyst. In at least one embodiment, the hydrocracking catalyst can be or can include Pt / ZSM-5 that contains Pt in an amount from 0.3 wt%, or 0.5 wt% to 0.6 wt%, 1 wt%, 2 wt%, based on the total weight of the hydrocracking catalyst.Separation of Ethane and Propane from the Hydrocracked Product

[0062] The separation of at least one of ethane and propane can be carried out via any suitable separation process. The separation process can also separate the aromatics product and a light fraction that can include methane, hydrogen, and other light gases such as nitrogen. In some embodiments, the separation of the products from the hydrocracked product can be obtained via one or more fractionation or distillation columns such as cryogenic distillation. In other embodiments, the separation of the products from the hydrocracked product can be obtained via one or more selective adsorption via size exclusion, taking advantage of the different size of the alkane molecules. The separation of the various products that can be obtained from the hydrocracked product are well-known to those skilled in the art. Suitable processes and systems for separating ethane, propane, the aromatic product, and optionally the light fraction that can include methane, hydrogen, and other light gases can include those described in U.S. Patent No.: 10,130,897.Hydrotreating Pyoil

[0063] As noted above, in some embodiments, the pyoil can optionally be hydrotreated with a hydrotreating catalyst and molecular hydrogen to remove at least one of a halogen, oxygen, and nitrogen from the pyoil to produce a hydrotreated pyoil, where at least a portion of the hydrotreated pyoil and naphtha can be hydrocracked. The optional hydrotreating of the pyoil can be useful when the plastic waste contains a relatively high concentration of one or more halogens, oxygen, and / or nitrogen. In other words, if the pyoil contains contaminants such ashalogen(s), oxygen, and / or nitrogen, the optional hydrotreating can be used to further reduce or even completely remove such contaminants from the pyoil.

[0064] In other embodiments, the hydrotreating catalyst can include at least one Group 8 to 10 metal, such as Fe, Co, Ni, Pt, Ru, Au, Rh, Ir, Ru, a mixture thereof, or a combination thereof, optionally supported on a catalyst support that can be or can include, but is not limited to, alumina, silica, silica-alumina, titania, zirconia, carbon, a zeolite, or a combination thereof. In some embodiments, the hydrotreating catalyst can include at least one Group 8 to 10 metal, such as Fe, Co, and / or Ni, and at least one Group 6 metal, such as Mo and / or W, optionally supported on catalyst support that can be or can include, but is not limited to, alumina, silica, silica-alumina, titania, zirconia, carbon, a zeolite, or a combination thereof.

[0065] In other embodiments, the hydrotreating catalyst can be a bulk metal catalyst, or a combination of stacked beds of supported and bulk metal catalyst. The term bulk metal catalyst means that the catalysts are unsupported. The bulk metal catalyst includes 30 wt% to 100 wt% of at least one Group 8 to 10 non-noble metal and at least one Group 6 metal, based on the total weight of the bulk metal catalyst, calculated as metal oxides. The bulk metal catalysts (also referred to as “bulk metal hydrotreating catalysts”) have a surface area of at least 10 m2 / g. In some embodiments, the bulk metal hydrotreating catalyst can include about 50 wt% to about 100 wt% or about 70 wt% to about 100 wt%, of at least one Group 8 to 10 non-noble metal and at least one Group 6 metal, based on the total weight of the catalyst, calculated as metal oxides.

[0066] In some embodiments, the bulk metal hydrotreating catalysts can have a surface area of at least 50 m2 / g or at least 100 m2 / g. Bulk metal hydrotreating catalysts can have a pore volume in a range from 0.05 ml / g, 0.1 ml / g, 0.3 ml / g, or 0.5 ml / g to 1 ml / g, 2 ml / g, 3 ml / g, 4 ml / g, or 5 ml / g, as determined by nitrogen adsorption. Typically, pores smaller than 1 nm are not present. In some embodiments, the bulk metal hydrotreating catalysts can have a median diameter of at least 50 nm or at least 100 nm. In some embodiments, the bulk metal hydrotreating catalysts can have a median diameter of not more than 5,000 pm or not more than 3,000 pm. In some embodiments, the median particle diameter of the bulk metal hydrotreating catalyst can be in a range from 0.1 pm to 50 pm or in a range from 0.5 pm to 50 pm. Various configurations for hydrotreating can include those described in U.S. Patent No.: 9,302,472.

[0067] In some embodiments, the pyoil can be hydrotreated at a molecular hydrogen partial pressure in a range from 0.1 MPa-g, 0.5 MPa-g, 0.7 MPa-g, 1 MPa-g, 3 MPa-g, 5 MPa-g, 10 MPa-g, 17 MPa-g. The hydrotreating can be caried out at a temperature in a range from 325°C, 350°C, 375°C, or 400°C to 450°C, 500°C, 550°C, or 575°C. The hydrotreating can be carriedout at a liquid hourly space velocity in a range from 0.1 g, 1 g, 3 g, or 5 g to 7 g, 9g, 10 g, or 12 g of pyoil / g catalyst / hour. In some embodiments, the pyoil can be hydrotreated at a molecular hydrogen partial pressure in a range from 0.1 MPa-g to 15 MPa-g, at a temperature in a range from 350°C to 550°C, and at a liquid hourly space velocity in a range from 0.1 g to 10 g of pyoil / g catalyst / hour.

[0068] In some embodiments, the hydrotreating catalyst can be or can include, but is not limited to, CoMo, CoW, NiMo, NiW, Fe, Pt, Ru, Au, Rh, Ir, a mixture thereof, or a combination thereof. In some embodiments, the hydrotreating catalyst can be supported on a catalyst support. In some embodiments, the optional catalyst support can be or can include, but is not limited to, alumina, silica, silica-alumina, titania, zirconia, carbon, a mixture thereof, a combination thereof.Saturation of Aromatics

[0069] In the present processes, the aromatics in the aromatic product can be hydrogenated or saturated without separating the butanes and pentanes therefrom. The saturation process can convert aromatic rich streams into naphthenes. In some embodiments, the saturation can be carried out at moderately high molecular hydrogen partial pressure over a non-noble metal catalyst such as Ni, Mo, a mixture thereof, or a combination thereof. In other embodiments, for deep hydrogenation, the saturation can be carried out at moderately high molecular hydrogen partial pressure over a noble metal catalyst such as Pt, Pd, Ir, Rh, Ru, a mixture thereof, or a combination thereof. In still other embodiments, the saturation can be carried out at moderately high molecular hydrogen partial pressure over one or more non-noble metal catalyst and one or more noble metal catalysts.

[0070] The molecular hydrogen that can be utilized in the optional hydrotreating process and the optional saturation process can be obtained from any suitable source, for example pure hydrogen, hydrogen exiting from a reformer process, or hydrogen obtained as a by-product from another refinery or chemical process. The molecular hydrogen can be 100% hydrogen or can be diluted with another gas, for example light alkanes, carbon dioxide, or an inert gas such as nitrogen. In some embodiments, the molecular hydrogen can contain 5 vol%, 10 vol%, 20 vol%, 30 vol% or 40 vol% to 50 vol%, 60 vol%, 70 vol%, 80 vol%, 90 vol%, or 100 vol%. Saturation catalysts can include 0.05 wt% to 10 wt%, preferably 0.1 wt% to 2 wt% of a metal such as platinum, palladium, ruthenium, rhodium, iridium, a mixture thereof, or a combination thereof, carried on a support that can be a zeolite or another support material such as a silica, alumina, titania or silica-alumina (including clays).

[0071] The saturation of the aromatics in the aromatic product can be carried out at a molecular hydrogen partial pressure in a range from 0.1 MPa-g, 0.3 MPa-g, 0.6 MPa-g, 1 MPa-g, 3 MPa-g, or 5 MPa-g to 7 MPa-g, 10 MPa-g, 12 MPa-g, 14 MPa-g, 15 MPa-g, or 17 MPa-g. The saturation of the aromatics in the aromatic product can be carried out at a temperature in arrange from 35°C, 50°C, 100°C, or 150°C to 200°C, 250°C, 300°C, 350°C, or 375°C. The saturation of the aromatics in the aromatic product can be carried out at a liquid hourly space velocity in a range from 0.1 g, 1 g, 3 g, or 5 g to 7 g, 9g, 10 g, or 12 g of feed / g catalyst / hour. In some embodiments, the saturation of the aromatics in the aromatic product can be carried out at a molecular hydrogen partial pressure in a range from 0.1 MPa-g to 15 MPa-g, at a temperature in arrange from 50°C to 350°C, and at a liquid hourly space velocity in a range from 0.1 g to 10 g of feed / g catalyst / hour.

[0072] In some embodiments, the saturating catalyst can be or can include, but is not limited to, Pt, Pd, Ir, Rh, Ru, a mixture thereof, or a combination thereof. In some embodiments, the saturating catalyst can optionally be supported on a catalyst support that can be or can include, but is not limited to, alumina, silica, silica-alumina, titania, zirconia, carbon, a mixture thereof, or a combination thereof.

[0073] As noted above, the saturated product or at least a portion thereof can be recycled and combined with an additional quantity of the pyoil and an additional quantity of the naphtha to produce additional hydrocracked product via hydrocracking. As also noted above, the aromatic product can also include one or more butanes and / or pentanes and the one or more butanes and / or pentanes can be present in the saturated product when the saturated product is combined with the additional quantity of the pyoil and the additional quantity of naphtha. In some embodiments, a weight ratio of the saturated product to the additional quantity of naphtha in the mixture of the saturated product, the additional quantity of the pyoil, and the additional quantity of the naphtha can be in a range from 0.01:1 to 1; 1, 0.1:1 to 0.5:1, or 0.1:1 to 0.3:1.Steam Cracking

[0074] Steam cracking is used to produce light olefins. In typical steam cracking processes, the hydrocarbon feed is first preheated and mixed with dilution steam in a convection section of the furnace. After preheating in the convection section, the vapor feed / dilution steam mixture is rapidly heated in a radiant section to achieve the desired thermal cracking. After the desired degree of thermal cracking has been achieved in the radiant section, the furnace effluentis rapidly quenched in either an indirect heat exchanger or by the direct injection of a quench oil stream.

[0075] A typical steam cracking furnace is described in U. S. Patent Application Publication No.: 2018 / 0170832. Steam cracking can be used for the conversion of various types of hydrocarbon feed materials rich in aliphatic hydrocarbons into lighter hydrocarbons rich in olefins. To that extent, in the present methods, the hydrocarbon material fed into the furnace contain ethane as a major component. For example, the fresh hydrocarbon material can contain, by weight of the total fresh feed, from al% to a2%, of ethane, where al and a2 can be, independently, 50, 55, 60, 65, 70, 75, 80, 85, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, 100, as long as al<a2.

[0076] The steam cracking furnace includes a radiant fire box in the lower portion thereof and a convection section in the upper portion thereof. The hydrocarbon feed that includes ethane is fed into a hydrocarbon inlet of an upstream portion of the convection section. A diluent steam stream is fed into a downstream portion of the convention section at a location downstream of the hydrocarbon inlet to mix with the hydrocarbon feed stream. The combined hydrocarbon / steam stream travels downward along the convection section. Because of hot gas traveling upwards inside the firebox, the hydrocarbon / steam feed mixture inside the convection section is gradually heated up as it travels along the tube. When it reaches the end of the convection section which is located immediately outside of the wall of furnace as the first fluid stream, its temperature reaches T1°C. The end of the convection section is connected to the start of a cross-over section of the steam cracking tube. The cross-over section is typically located outside of the wall of the furnace to avoid heating the hydrocarbon and stream mixture to an exceedingly high temperature where substantial cracking can occur prematurely. At the end of the cross-over section, a second fluid stream at T2°C. is obtained. The cross-over section is thermally insulated to prevent excessive heat loss with or without active heating. Where no active heating is applied, T2 is typically slightly lower than T1 as a result of heat loss and / or endothermal cracking reactions occurring if T1 is sufficiently high. The cross-over section ends with one or more critical flow nozzles, which are connected to a lower end of one or more vertical radiant tubes (radiant section of the steam cracking tube) installed inside the walls of the radiant zone of the furnace. The steam cracking tubes in the radiant section are typically heated externally by a series of flames generated by burners installed on the floor of the fire box and / or the side walls of the fire box. Operating conditions can be chosen such that a majority of the heat supplied to the radiant tubes are by radiation instead of convection or conduction. The fluid stream inside the radiant tubes travel at a very high space velocity whilebeing heated by the radiant heat from the flames. After a very short residence time in the vertical radiant tubes, at the end of the radiant tubes, which are located immediately outside of the furnace box, the fluid stream can reach a temperature of T3°C that is significantly higher than T2 and Tl, where the cracking of large hydrocarbon molecules to form small hydrocarbon molecules such as ethylene, propylene, and the like, are favored. The cracked fluid mixture stream exits the radiant section and can be quenched and subsequently separated to obtain the desired product fractions, such as ethylene, propylene, butadiene, and the like. Typically, in a steam cracking process, saturated hydrocarbon materials such as alkanes are fed into the process, and a cracked fluid mixture comprising higher concentrations of alkenes, typically having fewer carbon atoms and / or smaller molecular weight in molecules thereof than those in the hydrocarbon materials than the hydrocarbon feed, is obtained.

[0077] Typically, the heavier the hydrocarbon material fed into the steam cracking furnace, the lower the operation temperature, and the heavier the cracked fluid mixture tends to be. As indicated above, the process of the present invention can be used for steam cracking of various hydrocarbon materials as fresh feed, to obtain different cracked products, particularly olefins with different molecular sizes.

[0078] In some embodiments, the temperature at the lower portion of the convection zone, particularly at the end thereof (Tl), can be sufficiently high, such that significant cracking reactions occur in the lower portion of the convection section and the cross-over section before the second fluid stream enters into the radiant section, where a great majority of the steam cracking take place. Thus, compared to the feed mixture including all fresh feed, recycled hydrocarbon, and steam assuming no chemical reactions have taken place, the first fluid mixture exiting the end of the convection section and entering the cross-over section tends to have an overall olefins concentration.

[0079] As indicated above, typically T2<T1<T3. Where the cross-over section is not actively heated and merely thermally insulated outside of the furnace box, due to the endothermic nature of the cracking reactions, the temperature of the fluid stream inside the cross-over section decreases from the beginning to the end. Thus, the temperature differential T1-T2 can be in the range from el to e2°C, where el and e2 can be, independently, 25, 20, 15, 10, or even 5, as long as el<e2. In the cross-over section of the reactor, additional cracking is allowed to continue because of the relatively high temperature Tl of the first fluid mixture entering the cross-over section, even if T2<T1. Thus, assuming the feed includes olefins at a total concentration of CO mol% based on the total moles of the fluid species in the feed before any cracking reaction occurs; the second fluid stream includes olefins at a total concentrationof C2 mol% based on the total moles of the fluid species therein; then hl%<C2-C0<h2%, where hl and h2 can be, independently, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, as long as hl<h2.

[0080] The temperature differential T3-T2 can be in the range from fl to f2°C, where fl and f2 can be, independently, 35, 50, 75, 100, 150, 200, 250, or 260, as long as fl<f2. This significantly higher T3 would lead to a majority of the cracking reactions in the radiant section even though the residence time therein is typically very short, e.g., on the order of milliseconds to hundreds of milliseconds.

[0081] The cracking conditions, especially those in the radiant section, can be chosen to favor the thermal pyrolysis of the aliphatic hydrocarbon molecules in the feed material to produce smaller, unsaturated hydrocarbon molecules and hydrogen in the cracked fluid mixture. The unsaturated hydrocarbons tend to have higher economic value than the aliphatic feed and are used as industrial raw materials for making additional materials such as polymers.

[0082] At the end of the radiant section, the cracked fluid mixture is typically quenched immediately by a heat exchanger or by the injection of a quenching fluid stream. The quenched fluid stream is at a temperature where significant chemical reactions between and among the chemical species in the cracked fluid mixture is substantially stopped, preventing the formation of undesirable compounds that may form coke. The cracked fluid mixture can be separated in a downstream vessel by conventional methods such as condensation and evaporation to obtain various fractions: hydrogen, desirable unsaturated hydrocarbon fractions, and residual aliphatic hydrocarbons. The residual aliphatic hydrocarbons may be recycled into the steam cracking reactor, where it is further converted into desirable products, or alternatively, it may be combusted as a fuel for, e.g., producing the flames that heat the steam cracking furnace, particularly the radiant section.Ethane Steam Cracking

[0083] For ethane cracking, an ethane feed to the steam cracking reactor includes from > 50 mol% to 100 mol% of ethane. For example, the ethane feed can include ethane in a range from 50 mol%, 55 mol%, 60 mol%, 65 mol%, 70 mol%, or 75 mol% to 80 mol%, 85 mol%, 90 mol%, 95 mol%, 96 mol%, 97 mol%, 98 mol%, 99 mol%, or 100 mol%. As a minor component, propane can be present in the ethane feed as well, e.g., at a concentration < 50 mol%. For example, the ethane feed can include propane in a range from 5 mol%, 10 mol%, 15 mol%, 20 mol%, or 25 mol% to 30 mol%, 35 mol%, 40 mol%, 45 mol%, or 49.9 mol%. Under the steam cracking conditions, especially in the radiant section where the temperature is high, the cracking of ethane and propane are favored to produce methane, ethylene, propylene, hydrogen,acetylene, methylacetylene, which are smaller in molecular weight than ethane and / or propane. Larger molecules, such as C4, C5, and C6 hydrocarbons, can be produced as well, but typically at low concentrations. Upon separation in down-stream processes, C4, C5, and C6 olefins and aromatics can be obtained as valuable byproducts, and residual ethane and propane can be recycled to the steam cracking furnace as a portion of the overall feed.

[0084] T1 can be in the range from T1 (ethane) 1 to Tl(ethane)2°C, where T1 (ethane) 1 and Tl(ethane)2 can be, independently, 700, 710, 725, 750, 760, 770, 780, 800, or 825, as long as T1 (ethane) l<Tl(ethane)2; T2 can be in the range from T2(ethane)l to T2(ethane)2°C, where T2(ethane)l and T2(ethane)2 can be, independently, 690, 700, 720, 730, 740, 760, 770, 780, or 800, as long as T2(ethane)l<T2(ethane)2; and T3 can be in the range from T3 (ethane) 1 to T3(ethane)2°C, where T3(ethane)l and T3(ethane)2 can be, independently, 815, 830, 850, 875, 900, 925, 950, 960, 970, 980, 1,000, or 1,025, as long as T3 (ethane) l<T3(ethane)2.

[0085] The conversion of ethane in the process disclosed herein can be desirably high, generally higher than 50% and lower than 80%. At higher than 80%, the selectivity toward ethylene can be low. Thus, the conversion of ethane can be from Con(l)% to Con(2)%, where Con(l) and Con(2) can be, independently, 60, 62, 64, 66, 68, 70, 72, 74, 76, 78, 80, as long as Con(l)<Con(2).

[0086] In the steam cracking process disclosed herein for ethane, it can be desirable that the total concentration of C5 and C6 olefins, dienes and benzene in the cracked fluid mixture is in a range from xl mol% to x2 mol% based on the total moles of different species therein, where xl and x2 can be, independently, 1.0, 1.5, 2.0, 2.5, 3.0, 3.5, 4.0, 4.5, 5.0, 5.5, 6.0, 6.5, 7.0, 7.5, and 8.0, as long as xl<x2.

[0087] In the steam cracking process disclosed herein for ethane, it can be desirable that the process has a total severity index (SI) in the cracked fluid mixture in a range from si to s2, where si and s2 can be, independently, 0.50, 0.55, 0.60, 0.65, 0.70, 0.75, 0.80, 0.85, 0.90, 0.95, 1.00, 1.05, 1.10, 1.15, 1.20, 1.25, as long as sl<s2.Dehydrogenation of Propane

[0088] Paraffinic hydrocarbons can be catalytically dehydrogenated to olefinic hydrocarbons in catalytic dehydrogenation reactor. An exemplary dehydrogenation process is specifically described in U.S. Patent No.: 8,653,317. Other exemplary dehydrogenation processes and dehydrogenation catalysts include those described in U.S. Patent Nos.: 11, 607,702; 11,680,029; 11,760,702; 11,760,703; 11,773,336; 11,859,136; and 12,054,456; andU.S. Patent Application Publication Nos.: 2024 / 0271048; 2024 / 0316544; and 2025 / 0025860; and WO Publication Nos.: WO2023 / 183693.

[0089] Generally, dehydrogenation of lower alkanes includes contacting a gaseous stream of hydrocarbon with a dehydrogenation catalyst at a reaction temperature over a relatively short "contact time." In the dehydrogenation process, lower alkanes, for example ethane, propane, butanes, and / or pentanes are dehydrogenated to their corresponding olefins, for example ethylene, propylene, butenes, and pentenes.

[0090] Dehydrogenation catalysts for use in the present processes are active and are capable of dehydrogenating paraffins in less than a few seconds at ideal reaction temperatures. Generally, the dehydrogenation catalyst has a first component of tin, germanium, lead, indium, gallium, thallium or compounds thereof with an atomic ratio to a second component of a Group 8 metal such as Fe, Ru, Os, Co, Rh, Ir, Ni, Pd, or Pt within the range from 0.1 to 1000, 1 to 500, and from 1 to 200. An alkali metal or alkaline earth metal compound can also be present in an amount to provide from 0 to 2 percent or 0.1 to 1 percent metal, alkali metal in the catalyst.

[0091] A dehydrogenation catalyst can be used as such or diluted with an inert material, for example, refractory oxides and other ceramics, such as metal- or metalloid-carbides, oxides or nitrides. Examples include silicon carbide and alumina having a surface area of 50 m2 / g or less. The inert additive may be used at a concentration of the inert product of between 0 and 50 percent, preferably from 5 to 25 percent of the total catalyst.

[0092] Details on the preparation of hydrogenation catalysts suitable for use are described in U.S. Patent No.: 8,653,317 as analogous to those employed in WO Publication Nos.: W02005 / 077867 (US2008 / 0194891); WO2023 / 183693; W02002 / 096844; (U.S. Patent No.: 6,031,143, EP,0,905,112); U.S. Patent No.: 6,031,143; and EP Patent No.: EP0,637,578. Typically, the process of preparing the dehydrogenation catalysts includes dispersing precursors of the catalytic metals, for example, solutions of soluble salts of the catalytic metals onto the preformed support. Suitable soluble salts particularly include the nitrate salts of the first component, especially gallium nitrate, and complexes of the Group 8 metal, such as tetraamineplatinum. More particularly, the foregoing process of dispersion can comprise impregnation of the carrier with one or more solutions containing the precursors of the first and second components, especially gallium and platinum, along with any other components, followed by drying and calcination. An alternative method includes ion adsorption followed by the separation of the liquid portion of the adsorption solution, drying, and activation of the resultant solid. As another alternative, the carrier can be treated with volatile species of the desired metals. In the case of added alkali metals or alkaline earth metals, such compounds ortheir precursors can be added to the carrier prior to dispersion of the primary catalytic metals or compounds, followed, optionally, by calcination of the resulting solid. It will be understood by the skilled artisan that the actual species of each of the foregoing named components, under the conditions of their use as catalysts, may exist in the form of a compound, such as an oxide, and the metal or other component may be in an oxidation state other than that originally employed or designated herein.

[0093] A catalyst support can be prepared by dehydration of soluble aluminum salts, especially aluminum hydroxides or mixtures thereof with aluminum oxides, and optionally silicates, followed by heating in the presence of air to a temperature from 300°C to 800°C for time periods up to 24 hours. Additional compounds can optionally be present in the formulation in order to improve one or more physical properties of the support such as to increase abrasion resistance or decrease surface acidity. When silica is employed in the support, it is incorporated into the finished support by physically compounding it with the previously prepared alumina. Levels of silica incorporation can be from 0% to 5% or from 0.1% to 2%. In an embodiment, microspheroidal pseudo-bohemite is prepared by spray drying hydrated alumina so to form particles suitably having an average particle size from 5 to 500 micrometers. This product can be heated to a temperature up to 800°C for a time for up to 8 hours. The drying can be accomplished in multiple steps at various temperatures to prevent loss of surface area. For example, the particles can be air dried at 350°C for 2 hours followed by heating at a temperature from 500°C to 800°C, 550°C to 700°C for up to 4 hours. As is well known in the art, heating pseudobohemite to temperatures less than or equal to 800°C results in formation of the gamma alumina with substantially no formation of low surface area delta, theta or alpha crystalline phases, see, George J. Antos, et. al., ed., Catalytic Naphtha Reforming Science and Technology, Marcel Dekker, Inc., pg. 82, and M. Hill, et al., Chemistry of Materials (2007), v,19(ll) pp. 2877-2883.

[0094] The FIG. depicts an illustrative system 100 for converting plastic waste and naphtha to at least one of ethylene and propylene, according to one or more embodiments. The system 100 can include a pyrolysis unit 105, a hydrocracker 110, a product separation unit 115, and at least one of an ethane conversion unit 125 and a propane conversion unit 130. In some embodiments, the system 100 can also include a saturation unit 135. In some embodiments, the system 100 can also include an optional hydrotreating unit 145.

[0095] The pyrolysis unit 105 can be configured to receive plastic waste via line 101 and heat the plastic waste to a temperature in a range from 250°C top 550°C to produce a pyoil that can be recovered via line 107 and / or line 140 from the pyrolysis unit 105.

[0096] In some embodiments, at least a portion of the pyoil via line 107, naphtha via line 108, and molecular hydrogen via line 109 can be introduced into the hydrocracker 110. At least a portion of the pyoil and naphtha can be hydrocracked within the hydrocracker 110 to produce a hydrocracked product.

[0097] In other embodiments, at least a portion of the pyoil via line 140 and molecular hydrogen via line 141 can be introduced into the optional hydrotreating unit 145. At least a portion of the pyoil introduced via line 140 into the hydrotreating unit 145 can be hydrotreated in the presence of the molecular hydrogen and a hydrotreating catalyst within the hydrotreating unit 145 to produce a hydrotreated pyoil. In such embodiments, at least a portion of the hydrotreated pyoil via line 147, the naphtha via line 108, and the molecular hydrogen via line 109 can be introduced into the hydrocracker 110 to produce the hydrocracked product.

[0098] In other embodiments, a first portion of the pyoil via line 107 can be introduced into the hydrocracker 110 and a second portion of the pyoil via 140 can be introduced into the hydrotreating unit 145 to produce the hydrotreated pyoil that can be introduced via line 147 into the hydrocracker 110 along with the naphtha via line 108 and the molecular hydrogen via line 109 to produce hydrocracked product.

[0099] The hydrocracked product can be recovered via line 111 from the hydrocracker 110 and introduced into the product separation unit 115. In some embodiments, the product separation unit 115 can include one or more fractionation or distillation columns or any other suitable separation unit. From the product separation unit 115 an ethane product via line 117, a propane product via line 119, and an aromatic product via line 121 can be obtained. In some embodiments, at least a portion of the ethane via line 117 can be introduced into the ethane conversion unit 125, e.g., a steam cracker, to produce ethylene that can be recovered via line 127. In some embodiments, at least a portion of the propane via line 119 can be introduced into the propane conversion unit 130, e.g., a propane dehydrogenation reactor or catalytic dehydrogenation reactor, to produce propylene that can be recovered via line 131.

[0100] In some embodiments, the aromatic product via line 121 and molecular hydrogen via line 123 can be introduced into the optional saturation unit 135. At least a portion of the aromatics in the aromatic product can be saturated in the presence of the molecular hydrogen and a saturating catalyst to produce a saturated product that can be recovered via line 137 from the saturation unit 135. At least a portion of the saturated product via line 137 can be introduced or recycled to the hydrocracker 110 along with an additional quantity of the naphtha via line 108, an additional quantity of the molecular hydrogen via line 109, and at least one of anadditional quantity of the pyoil via line 107 and at least a portion of the hydrotreated pyoil via line 147 to produce additional hydrocracked product.Examples:

[0101] The foregoing discussion can be further described with reference to the following non-limiting examples.

[0102] Pyrolysis (Example 1) and pyrolysis / hydrocracking (Examples 2-6) experiments were performed in a modified tandem pyrolyzer-catalytic reactor unit. The pyrolyzer-catalytic reactor unit included two reactors connected in tandem. The first reactor was a micro-pyrolyzer and the second reactor was used as a second pyrolysis unit (Example 1) or a hydrocracking unit (Examples 2-6). The first reactor and the second reactor were independently temperature controlled, which allowed for evaluation of pyrolysis and subsequent cracking at different temperatures. In Example 1, the second reactor was packed with quartz and served as a second pyrolysis unit. In Examples 2-6, the second reactor contained 0.6% Pt / ZSM-5 as the hydrocracking catalyst.

[0103] In the experiments, the reactor unit was positioned on top of a gas chromatograph / mass selective detector / flame ionization detector (GC / MSD / FID) instrument (Agilent). In Example 1, approximately 0.5 mg of a plastic waste sample was placed in a stainless steel metal cup that was loaded into the first reactor (pyrolyzer) at a pre-set temperature. The plastic waste was heated to produce pyoil. The pyoil from the first reactor was swept by helium (60 seem) into the second reactor that was packed with quartz.

[0104] In Examples 2-6, the first reactor was empty and served as a pyrolysis reactor and the second reactor was packed with the hydrocracking catalyst. In addition to the liquid effluent from the first reactor and the helium sweep gas, molecular hydrogen (H2) was introduced into the second reactor, mixed with the liquid effluent, and the mixture was hydrocracked in the presence of the hydrocracking catalyst. The effluent from the second reactor in all examples was trapped (at -195°C) via a micro-jet cooled with liquid nitrogen. After a pre-determined sample trapping period (5 minutes), the trapped reaction sample was warmed up and passed through the GC column for separation. The effluent from the GC column was split 3 / 1 (v / v) and sent to the FID for quantification and the MSD for identification, respectively.

[0105] For separation, a 30 m x 0.25 mm x 0.1 pm DB-5HT column (Agilent J&W) was used. The GC conditions included: helium carrier gas, 1.4 cc / min column flow; 25 / 1 split ratio; temperature: 35°C initial (5 minute hold), ramping to 200°C at 7.5°C / min and then to 325°Cat 20°C / min and held for 10 minutes. Molecular hydrogen, if formed, cannot be trapped using the micro-jet and therefore was not detected using this technique.Example 1

[0106] A waste plastic sample was thermally pyrolyzed at 500°C and ambient pressure in the first reactor and the second reactor was packed with quartz chips and held at 250°C. The waste plastic sample was EXCEED™ 1018, which is a LLDPE that included about 8 wt% hexene co-monomer. More than 80 wt% of the products were in the C9+ range, which includes primarily alkanes, a-olefins, and dienes. Therefore, in subsequent examples, n-hexadecane and 1 -hexadecene were used as model compounds to represent the pyoil. The pyoil produced by thermally pyrolyzing the LLDPE sample had the composition shown in Table 1 below.

[0107] The model compounds used to represent naphtha were n-heptane (n-HPT), 2-methylhexane (2-MH), methylcyclohexane (MCH), and toluene (TOL). An amount (0.3 micro-liters) of liquid sample was injected into the tandem reactor. The first reactor was empty and kept at 500°C and ambient pressure and the second reactor was packed with the hydrocracking catalyst and kept at a temperature of 500°C and ambient pressure. In addition to the model compounds fed into the first reactor, helium (60 mL / min) was also passed through the first reactor. The effluent from the first reactor and hydrogen (20% based on the combined amount of helium and hydrogen) was introduced into the second reactor. Table 2 shows the reactor effluent composition that was obtained from the hydrocracking reactor.

[0108] As can be seen from Table 2, ethane, propane, and butanes were major products for the n-heptane, 2-methylhexane, and methylcyclohexane feeds, respectively, whereas very little conversion was seen for toluene feed under the selected reaction conditions.Example 3

[0109] An amount (0.5 mg) of 1 -hexadecene (model pyoil) was injected into the tandem reactor. The first reactor was empty and kept at 500°C and ambient pressure and the second reactor was packed with the hydrocracking catalyst and kept at a temperature of 500°C or 550°C and ambient pressure. In addition to the feed, helium (60 mL / min) was passed through the first reactor. The effluent from the first reactor and hydrogen (20% based on the combined amount of helium and hydrogen) was introduced into the second reactor. Run 1 and Run 2 that were carried out at a hydrocracking temperature of 550°C were duplicate runs that used the same load of catalyst without regeneration in between the two runs. Table 3 shows the reactor effluent composition that was obtained from the hydrocracking reactor.

[0110] As can be seen from Table 3, hydrocracking at 500°C produced a reactor effluent that primarily included propane, butanes, and pentanes as the alkane products with a relatively low yield to ethane. Hydrocracking at 550°C, however, significantly increased the ethane yield at the expense of propane, while the total amount of aromatics was comparable to that produced by hydrocracking at 500°C.Example 4[oni] An amount (0.5 mg) of n-hexadecane (model pyoil) was injected into the tandem reactor. The first reactor was empty and kept at 500°C and ambient pressure. The second reactor was packed with the hydrocracking catalyst and kept at a temperature of 500°C or 550°C and ambient pressure. In addition to the feed (0.3 micro-liters), helium (60 mL / min) was passed through the first reactor. The effluent from the first reactor and hydrogen (20% based on the combined amount of helium and hydrogen) was introduced into the second reactor. Run 1 and Run 2 that were carried out at a hydrocracking temperature of 500°C were duplicate runs that used the same load of catalyst without regeneration in between the two runs. Likewise, Run 1 and Run 2 that were carried out at a hydrocracking temperature of 550°C were duplicate runs that used the same load of catalyst without regeneration in between the two runs. Table 4 shows the reactor effluent composition that was obtained from the hydrocracking reactor.

[0112] As can be seen from Table 4, the ethane yield was greater at 500°C than at 550°C and the aromatics yield increased when the hydrocracking temperature increased from 500°C to 550°C.Example 5

[0113] A 70 / 30 (wt / wt) blend of n-heptane (model naphtha) with 1-hexadecene (model pyoil) was used in this example. The pyrolysis reactor was empty and kept at 500°C and ambient pressure for all four runs. The second reactor was packed with the hydrocracking catalyst and kept at a temperature of 500°C and ambient pressure. In addition to the feed (0.3 micro-liters) into the first reactor, helium (60 mL / min) was also passed through the first reactor. The effluent from the first reactor and hydrogen (20% based on the combined amount of helium and hydrogen) was introduced into the second reactor. The expected product yields at 500°C is also shown in Table 5. Run 1 and Run 2 that were carried out at a hydrocracking temperature of 550°C were duplicate runs that used the same load of catalyst without regeneration in between the two runs. An amount (0.3 micro-liters) of the mixture was introduced into the pyrolysis reactor. Table 5 shows the reactor effluent composition that was obtained from the hydrocracking reactor.

[0114] As shown in Table 5, without catalyst (second reactor was packed with quartz), no / little conversion was observed for this feed mixture. With the hydrocracking catalyst, however, near complete conversion was achieved for both n-heptane and 1-hexadecene and the major products were ethane, propane, butanes, and pentanes. The total yield to ethane and propane was approximately 68% at 500°C and approximately 60% at 550°C. The aromatics yield almost doubled when the hydrocracking temperature increased from 500°C to 550°C.Surprisingly and unexpectedly, the total yield to ethane and propane of 67.8 wt% achieved at 500°C was higher than the 63.5 wt% that was expected to be obtained from the 70 / 30 weight ratio of n-heptane / 1 -hexadecene. In addition, the total yield to benzene, toluene, and xylenes (BTX) of 16.7 wt% was significantly less than the 23.3 wt% that was expected to be obtained from the 70 / 30 weight ratio of n-heptane / 1 -hexadecene. These unexpected results indicate the benefits of converting pyoil and naphtha together via hydrocracking.Example 6

[0115] A 70 / 30 (wt / wt) blend of n-heptane (model naphtha) with n-hexadecane (model pyoil) was used in this example. The pyrolysis reactor was empty and kept at 500°C and ambient pressure for all three runs. The second reactor was packed with the hydrocracking catalyst and kept at a temperature of 500°C and ambient pressure or 550°C and ambient pressure. In addition to the feed (0.3 micro-liters) into the first reactor, helium (60 mL / min) was also passed through the first reactor. The effluent from the first reactor and hydrogen (20% based on the combined amount of helium and hydrogen) was introduced into the second reactor. The expected product yields at 500°C is also shown in Table 5. Table 6 shows the reactor effluent composition that was obtained from the hydrocracking reactor.

[0116] As shown in Table 6, without catalyst (second reactor was packed with quartz), no / little conversion was observed for this feed mixture. With the hydrocracking catalyst, however, near complete conversion was achieved for both n-heptane and 1 -hexadecene and the major products were ethane, propane, butanes, and pentanes. The total yield to ethane andpropane was approximately 71% at 500°C and approximately 61% at 550°C. The aromatics yield more than doubled when the hydrocracking temperature increased from 500°C to 550°C. Surprisingly and unexpectedly, the total yield to ethane and propane of 71.1 wt% achieved at 500°C was higher than the 66.7 wt% expected from the weighted average of the 70 / 30 weight ratio of n-heptane / n-hexadecane. In addition, the total yield to benzene, toluene, and xylenes (BTX) of 13.9 wt% was significantly less than the 19.4% that was expected to be obtained from the weighted average of the 70 / 30 weight ratio of n-heptane / n-hexadecane. These unexpected results indicate the benefits of converting pyoil and naphtha together via hydrocracking.

[0117] Various terms have been defined above. To the extent a term used in a claim is not defined above, it should be given the broadest definition persons in the pertinent art have given that term as reflected in at least one printed publication or issued patent. Furthermore, all patents, test procedures, and other documents cited in this application are fully incorporated by reference to the extent such disclosure is not inconsistent with this application and for all jurisdictions in which such incorporation is permitted.

[0118] While the foregoing is directed to embodiments of the present invention, other and further embodiments of the invention may be devised without departing from the basic scope thereof, and the scope thereof is determined by the claims that follow.

Claims

CLAIMS:What is claimed is:

1. A process for converting plastic waste and naphtha to at least one of ethylene and propylene, comprising:(I) heating the plastic waste to produce a pyoil;(II) hydrocracking the pyoil and the naphtha in the presence of molecular hydrogen and a hydrocracking catalyst to produce a hydrocracked product comprising ethane, propane, and aromatics;(III) separating at least one of ethane and propane from the hydrocracked product; and (IVa) converting at least a portion of the ethane, if the ethane is separated from the hydrocracked product, to ethylene; or(IVb) converting at least a portion of the propane, if the propane is separated from the hydrocracked product, to propylene.

2. The process of claim 1, wherein the ethane and propane are separated from the hydrocracked product, and wherein at least a portion of the ethane is converted to ethylene in step (IVa) and at least a portion of the propane is converted to propylene in step (IVb).

3. The process of claim 1 or claim 2, wherein the plastic waste comprises one or more polymers.

4. The process of any one of claims 1 to 3, wherein the plastic waste comprises polyethylene, polypropylene, polystyrene, polyethylene terephthalate), poly(vinyl chloride), poly(vinyl dichloride), polyamide, polyurethane, or a mixture thereof.

5. The process of any one of claims 1 to 4, wherein the plastic waste is heated to a temperature in a range from 250°C to 550°C to produce the pyoil.

6. The process of any one of claims 1 to 5, wherein the hydrocracking is carried out at a molecular hydrogen partial pressure in a range from 0.1 MPa-g to 10 MPa-g and at a temperature in a range from 350°C and 600°C.

7. The process of any one of claims 1 to 6, wherein the hydrocracking catalyst comprises a metal function and an acid function.

8. The process of claim 7, wherein the metal function comprises Ni, Pt, Pd, Co, Rh, Ir, Ru, Re, In, Sn, Zn, a mixture thereof, or a combination thereof, and wherein the acid function comprises a zeolite selected from MFI, MOR, FAU, MWW, BEA, or a mixture thereof.

9. The process of any one of claims 1 to 6, wherein the hydrocracking catalyst comprises Ni / MFI, Ni / MOR, Ni / FAU, Ni / BEA, Pt / MFI, Pt / MOR, Pt / FAU, Pt / BEA, Pt-Ir / MFI, Pt-Re / MFI, Pt-Ru / MFI, or a mixture thereof.

10. The process of any one of claims 1 to 9, wherein the hydrocracking catalyst operates at a liquid hourly space velocity in a range from 0.1 g to 10 g of a combined amount of the pyoil, the naphtha, and any saturated product per g of hydrocracking catalyst per hour.

11. The process of any one of claims 1 to 10, wherein the ethane is steam cracked to produce the ethylene.

12. The process of any one of claims 1 to 11, wherein the propane is catalytically dehydrogenated to produce the propylene.

13. The process of any one of claims 1 to 12, wherein a weight ratio of the pyoil to the naphtha in step (II) is in a range from 0.01:1 to 100: 1.

14. The process of any one of claims 1 to 13, further comprising:separating an aromatic product from the hydrocracked product;saturating at least a portion of the aromatics in the aromatic product in the presence of molecular hydrogen and a saturating catalyst to produce a saturated product; and hydrocracking an additional quantity of the pyoil, an additional quantity of the naphtha, and at least a portion of the saturated product in step (II) to produce additional hydrocracked product.

15. The process of claim 14, wherein the aromatic product is saturated at a molecular hydrogen partial pressure in a range from 0.1 MPa-g to 15 MPa-g and at a temperature in a range from 50°C to 350°C.

16. The process of claim 14 or claim 15, wherein the saturating catalyst comprises Pt, Pd, Ir, Rh, Ir, Ru, a mixture thereof, or a combination thereof.

17. The process of any one of claims 14 to 16, wherein the aromatic product further comprises one or more butanes and one or more pentanes, and wherein the one or more butanes and the one or more pentanes are present in the saturated product when the at least a portion of the saturated product is hydrocracked with the additional quantity of the pyoil and the additional quantity of the naphtha in step (II).

18. The process of any one of claims 14 to 17, wherein a weight ratio of the saturated product to the naphtha in step (II) is in a range from 0.01:1 to 1:1.

19. The process of any one of claims 1 to 18, wherein the hydrocracking in step (II) is carried out in a hydrocracking zone, and wherein the pyoil and the naphtha are introduced separately into the hydrocracking zone.

20. The process of any one of claims 1 to 18, wherein the hydrocracking in step (II) is carried out in a hydrocracking zone, and wherein a mixture of the pyoil and the naphtha is into the hydrocracking zone.

21. The process of any one of claims 1 to 18, further comprising hydrotreating the pyoil produced in step (I) with a hydrotreating catalyst and molecular hydrogen to remove at least one of a halogen, oxygen, and nitrogen from the pyoil to produce a hydrotreated pyoil, wherein the hydrotreated pyoil is hydrocracked in step (II).

22. The process of claim 21, wherein the pyoil is hydrotreated at a molecular hydrogen partial pressure in a range from 0.1 MPa-g to 15 MPa-g and at a temperature in a range from 350°C to 550°C.

23. The process of claim 21 or claim 22, wherein the hydrotreating catalyst comprises CoMo, CoW, NiMo, NiW, Fe, Pt, Ru, Au, Rh, Ir, Ru, a mixture thereof, or a combination thereof.

24. The process of any one of claims 21 to 23, wherein the hydrocracking in step (II) is carried out in a hydrocracking zone, and wherein the pyoil and the naphtha are introduced separately into the hydrocracking zone.

25. The process of any one of claims 21 to 23, wherein the hydrocracking in step (II) is carried out in a hydrocracking zone, and wherein a mixture of the pyoil and the naphtha is into the hydrocracking zone.

26. The process of any one of claims 1 to 25, wherein hydrocracked product comprises ethane in an amount from 5 wt% to 95 wt%, propane in an amount from 5 wt% to 95 wt%, and aromatics in an amount from 0.5 wt% to 20 wt%, based on the total weight of the hydrocracked product.

27. The process of any one of claims 1 to 25, wherein the hydrocracked product comprises at least 10 wt% of ethane, at least 30 wt% of propane, and less than 20 wt% of aromatics, based on the total weight of the hydrocracked product.

28. The process of any one of claims 1 to 25, wherein the hydrocracked product comprises at least 50 wt% of a combined amount of ethane and propane, based on the total weight of the hydrocracked product.

29. The process of any one of claims 1 to 25, wherein the hydrocracked product comprises 50 wt% to 90 wt% of a combined amount of ethane and propane and less than 20 wt%, less of aromatics, based on the total weight of the hydrocracked product.

30. The process of any one of claims 1 to 25, wherein the hydrocracked product comprises 50 wt% 90 wt% of a combined amount of ethane and propane and less than 15 wt% of a combined amount of butanes and pentanes, based on the total weight of the hydrocracked product.

31. The process of any one of claims 1 to 25, wherein the hydrocracked product comprises 65 wt% to 90 wt% of a combined amount of ethane and propane and less than 15 wt% of aromatics, based on the total weight of the hydrocracked product.

32. A process for converting plastic waste and naphtha to at least one of ethylene and propylene, comprising:heating the plastic waste to a temperature of up to 550°C to produce a pyoil; and hydrocracking the pyoil and naphtha in the presence of molecular hydrogen and a hydrocracking catalyst at a molecular hydrogen partial pressure in a range from 0.1 MPa-g to 10 MPa-g and at a temperature in a range from 350°C to 600°C to produce a hydrocracked product, wherein:the hydrocracking catalyst comprises Pt / ZSM-5, Pt-Ir / ZSM-5, PtSn / ZSM-5, Pt-Ru / ZSM-5, Pt-Rh / ZSM-5, Pt / MOR, Pt / FAU, and Pt / BEA, Ni / ZSM-5, or a mixture thereof, andthe hydrocracked product comprises at least 20 wt% of ethane, at least 40 wt% of propane, and less than 20 wt% of aromatics.

33. The process of claim 32, wherein:the hydrocracked product further comprises one or more butanes and one or more pentanes,the aromatics are saturated in the presence of a saturating catalyst at a molecular hydrogen partial pressure in a range from 0.1 MPa-g to 15 MPa-g and at a temperature in a range from 50°C and 350°C to produce a saturated product,the saturating catalyst comprises Pt-Pd, Pt-Ir, or Ir-Rh, andat least apportion of the saturated product is hydrocracked with an additional quantity of the pyoil and an additional quantity of the naphtha.

34. A system for converting plastic waste and naphtha to at least one of ethylene and propylene, comprising:a pyrolysis furnace configured to heat the plastic waste to produce a pyoil;a hydrocracker configured to hydrocrack at least a portion of the pyoil and the naphtha in the presence of molecular hydrogen and a hydrocracking catalyst to produce a hydrocracked product comprising ethane, propane, and aromatics;a product separation unit configured to separate at least one of the ethane and the propane from the hydrocracked product; anda steam cracker configured to convert at least a portion of the ethane, if the ethane is separated from the hydrocracked product, to ethylene; ora catalytic dehydrogenation reactor configured to convert at least a portion of the propane, if the propane is separated from the hydrocracked product, to propylene.

35. The system of claim 34, wherein the product separation unit is configured to separate an aromatic product from the hydrocracked product, the system further comprising:a saturation reactor configured to saturate at least a portion of the aromatics in the aromatic product in the presence of a saturating catalyst and molecular hydrogen to produce a saturated product; anda recycle line configured to convey at least a portion of the saturated product into the hydrocracker.

36. The system of claim 34 or claim 35, further comprising:a hydrotreater configured to hydrotreat at least a portion of the pyoil produced in the pyrolysis furnace in the presence of a hydrotreating catalyst and molecular hydrogen to remove at least one of a halogen, oxygen, and nitrogen from the pyoil to produce a hydrotreated pyoil, wherein the hydrocracker is configured to hydrocrack at least a portion of the hydrotreated pyoil and the naphtha in the presence of molecular hydrogen and the hydrocracking catalyst to produce the hydrocracked product.

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