Process for manufacturing cyclohexanone from plastic waste and chemical products based on cyclohexanone manufactured from plastic waste

Abstract

The present invention relates to a process and a chemical plant for separating benzene from a liquid stream comprising at least one pyrolysis oil which is manufactured from plastic waste and further converting said benzene into cylcohexanone. The cyclohexanone is suited as a precursor for azepan-2-one (ε-caprolactam) and hexanedioic acid which are based (at least a portion thereof) on benzene manufacturing from plastic waste. Furthermore, polyamide-6 and polyamide-66 can be manufactured by the process according to the present invention.

Description

[0001] Process for manufacturing cyclohexanone from plastic waste and chemical products based on cyclohexanone manufactured from plastic waste

[0002] Technical Area

[0003] The present invention relates to a process for manufacturing cyclohexanone and chemical products based on cyclohexanone from plastic waste.

[0004] Background of the invention

[0005] Cyclohexanone is an important intermediate product in the chemical industry from which chemicals such as azepan- 2-one (s-caprolactam) and hexanedioic acid are manufactured. Azepan-2-one is the monomer from which poly(azepan-2-one) (polyamide-6, PA6) is produced. Hexanedioic acid is one of the two monomers from which poly[imino(1,6-dioxohexamethylene) iminohexamethylene] (polyamide-66, PA66) is produced.

[0006] The usual starting material for the manufacture of cyclohexanone is benzene, which is isolated from fossil sources such as processed crude oil. Benzene is hydrogenated to form cyclohexane which is then oxidized to cyclohexanone. Accordingly, cyclohexanone, azepan-2-one, hexanedioic acid, poly(azepan-2-one) and poly[imino(1 ,6- dioxohexamethylene) iminohexamethylene] produced from benzene of fossil origin also have a fossil origin.

[0007] Amid global warming and climate change, it has become a global incentive to reduce fossil emissions. By utilizing recycled feedstock, the chemical industry can significantly reduce its dependence on virgin resources, leading to a decrease in resource depletion and environmental pollution.

[0008] The production of chemicals and plastics using pyrolysis oil from the pyrolysis of plastic waste as co-feedstock is disclosed in US / 2023 / 0016550A1 . The direct separation of benzene from plastic pyrolysis oils without steam cracking for manufacture of cyclohexanone is not disclosed therein.

[0009] A process for separating C6-C8 aromatic hydrocarbons from plastic pyrolysis oils is disclosed in WO2018 / 055555A1 . The process comprises a hydroalkylating unit in which a first "heavies stream” is converted, and a steam cracking unit in which a "treated hydrocarbon stream” is converted. The resulting streams from both units are then combined in a second separating unit in which C6-C8 aromatic hydrocarbons can be separated.

[0010] It is a first objective of the present invention to provide a process for manufacturing cyclohexanone from plastic waste.

[0011] It is a second objective to provide a process for manufacturing azepan-2-one from cyclohexanone of which at least a portion is manufactured from plastic waste. It is a third objective to provide a process for manufacturing poly(azepan-2-one) from azepan-2-one of which at least a portion is manufactured from cyclohexanone which is manufactured from plastic waste.

[0012] It is a third objective to provide a process for manufacturing hexanedioic acid from cyclohexanone which is manufactured from plastic waste.

[0013] It is a fourth objective to provide hexanedioic acid manufactured from plastic waste for manufacturing poly[imino(1 ,6- dioxohexamethylene) iminohexamethylene].

[0014] Summary of the Invention

[0015] These problems are solved by a process for manufacturing cyclohexanone from benzene, the process comprising the steps a) providing benzene b) providing hydrogen, c) contacting benzene provided in step a) with hydrogen provided in step b) in the presence of a first heterogeneous catalyst whereby cyclohexane is formed, d) oxidizing the cyclohexane formed in step c) in the presence of oxygen and, optionally, a second heterogeneous catalyst, whereby cyclohexanone is formed, characterized in that the at least a portion of the benzene provided in a) is manufactured by the steps a1) providing a liquid stream S1 comprising at least one pyrolysis oil, the liquid stream S1 further comprising C6-C8 aromatic hydrocarbons, organic compounds comprising at least one heteroatom and compounds having C-C double and / or C-C triple bonds, a2) providing a stream S2, the stream S2 comprising H2, a3) feeding the liquid stream S1 and the stream S2 into a hydrogenation unit HU1 in which at least a portion of the components of the liquid stream S1 reacts with stream S2 in a hydrogenation reaction whereby a liquid stream S3 is formed, wherein the liquid stream S3 is depleted in compounds having C-C double and / or C-C triple bonds in respect to liquid stream S1, and optionally feeding at least a portion of a liquid recycle steam S3', said liquid recycle stream S3' separated from the liquid stream S3, into said hydrogenation unit HU1, preferably wherein the mass ratio " liquid recycle steam S3' : liquid stream S3 ” preferably ranges between from about 1:1 to about 30:1, more preferably from about 5:1 to about 20:1 and most preferably from about 10:1 to about 15:1, a4) subjecting at least a portion or the remaining portion of the liquid stream S3 to a distillation unit DU in which the at least portion or remaining portion of liquid stream S3 is separated into a value product containing stream S4 and a liquid stream S5, wherein the value product containing stream S4 comprises C6-C8 aromatic hydrocarbons and organic compounds comprising at least one heteroatom, a5) subjecting the value product containing stream S4 to a hydrogenation unit HU2 in which the stream S4 is converted into a stream S6, wherein the stream S6 comprises C6-C8 aromatic hydrocarbons and is depleted in organic compounds comprising at least one heteroatom and / or C-C double bonds in respect to stream S4, and a6) separating benzene from stream S6 in an aromatic hydrocarbon extraction unit AEU.

[0016] These problems are further solved by a chemical plant for manufacturing cyclohexanone from benzene from a liquid stream comprising at least one pyrolysis oil, the chemical plant comprising

[0017] (I) at least one first hydroprocessing unit HU 1 , the at least one first hydroprocessing unit HU1 comprising at least one inlet and at least one outlet,

[0018] (II) optionally a recycle unit downstream of and fluidically connected to the inlet and the outlet of the first hydroprocessing unit HU1,

[0019] (ill) a distillation unit DU downstream of and fluidically connected to the outlet of the first hydroprocessing unit HU1, the distillation unit DU having a bottom outlet BO and a head outlet HO,

[0020] (iv) a second hydroprocessing unit HU2 downstream of and fluidically connected to the head outlet HO of the distillation unit DU,

[0021] (v) at least one aromatic hydrocarbon extraction unit AEU which is downstream and fluidically connected to the second hydroprocessing unit HU2.

[0022] Said chemical plant is suited for steps a1) to a6) and providing benzene in step a) of the process according to the present invention.

[0023] The process according to the present invention provides the following advantages:

[0024] First, cyclohexanone can be manufactured from plastic waste and has therefore a recycle-content of 100 % in case all benzene provided in step a) is manufactured by steps a1) to a6). Cyclohexanone having a recycle-content of less than 100 % can also be manufactured by the method according to the present invention in case not all benzene provided in step a) is manufactured by steps a1) to a6) and instead manufactured e.g., from a fossil feedstock. Accordingly, the process according to the present invention also enables manufacture of cyclohexanone with a desired recycle-content.

[0025] Second, the cyclohexanone manufactured from plastic waste and therefore having a recycle-content can be used as the feedstock for manufacturing azepan-2-one, which, accordingly, has also a recycle-content of up to 100 % in case all cyclohexanone is manufactured from benzene provided in step a) is manufactured by steps a1) to a6). Azepan-2- one having a recycle-content of less than 100 % can be manufactured from cyclohexanone having a recycle-content of less than 100 %. Accordingly, the process according to the present invention also enables manufacture of azepan- 2-one with a desired recycle-content.

[0026] Third, the azepan-2-one manufactured from plastic waste and therefore having a recycle-content can be used as the feedstock for manufacturing poly(azepan-2-one), which, accordingly, has also a recycle-content of up to 100 % in case all azepan-2-one is manufactured from benzene provided in step a) is manufactured by steps a1) to a6). Poly(azepan-2-one) having a recycle-content of less than 100 % can be manufactured from azepan-2-one having a recycle-content of less than 100 %. Accordingly, the process according to the present invention also enables manufacture of poly(azepan-2-one) with a desired recycle-content.

[0027] Fourth, in case the plastic waste from which poly(azepan-2-one) having a recycle-content is produced comprises poly(azepan-2-one), the process according to the present invention is a closed recycling loop for poly(azepan-2-one).

[0028] Fifth, the cyclohexanone manufactured from plastic waste and therefore having a recycle-content can be used as the feedstock for manufacturing hexanediotic acid, which, accordingly, has also a recycle-content of up to 100 % in case all cyclohexanone is manufactured from benzene provided in step a) is manufactured by steps a1) to a6). Hexanedioic acid having a recycle-content of less than 100 % can be manufactured from cyclohexanone having a recycle-content of less than 100 %. Accordingly, the process according to the present invention also enables manufacture of hexanedioic acid with a desired recycle-content.

[0029] Sixth, the hexanedioic acid manufactured from plastic waste and therefore having a recycle-content can be used as the feedstock for manufacturing poly[imino(1,6-dioxohexamethylene) iminohexamethylene], which, accordingly, has a recycle-content of up to 50 % in case all hexanedioic acid is manufactured from benzene provided in step a) is manufactured by steps a1) to a6) and the second monomer hexane-1 ,6-diamine is manufactured from a fossil feedstock and 100 % in case the second monomer hexane-1 ,6-diamine is also manufactured from plastic waste.

[0030] Poly[imino(1,6-dioxohexamethylene) iminohexamethylene] having a recycle-content of less than 100 % can be manufactured from hexanedioic acid having a recycle-content of less than 100 %. Accordingly, the process according to the present invention also enables manufacture of poly[imino(1,6-dioxohexamethylene) iminohexamethylene] with a desired recycle-content.

[0031] Seventh, in case the plastic waste from which poly[imino(1,6-dioxohexamethylene) iminohexamethylene] having a recycle-content is produced comprises poly[imino(1,6-dioxohexamethylene) iminohexamethylene], the process according to the present invention is a closed recycling loop for poly[imino(1,6-dioxohexamethylene) iminohexamethylene].

[0032] Eight, in manufacture of benzene manufactured from plastic waste according to steps a1) to a6) undesired polymerization and fouling is suppressed (see Examples).

[0033] Figure 1 shows a method in which a recycle stream from a second hydroprocessing unit into a first hydroprocessing unit is utilized. Such a recycle stream is employed in the method disclosed in AU 2021 / 222788 A1 and was used therefore as comparative example in the examples section. Figure 2 shows the process for manufacturing a mixture comprising cyclohexanone from benzene according to the first embodiment of the present invention.

[0034] Figure 3 shows the process for manufacturing a mixture comprising cyclohexanone from benzene according to the second embodiment of the present invention.

[0035] Detailed description of the invention

[0036] The present invention is further described below with reference to the embodiments, but the present invention is not limited to these embodiments, and any modifications of these embodiments, combinations of these embodiments or substitutions within the basic spirit of the present invention are still within the scope of the present invention as claimed.

[0037] Definitions:

[0038] In the context of the present description and the accompanying claims, the term "about” preferably means a deviation of the thus described value of ±10%. In the context of the present invention, the term “combinations thereof” is inclusive of one or more of the recited elements. In the context of the present invention, the term “mixture thereof” is inclusive of one or more of the recited elements. The term “recycle-content” is defined herein as amount or percentage of recycled materials used in a product or material. It indicates the extent to which recycled materials have been incorporated into the manufacturing or production process. The term “non-fossil feedstock” is defined herein as a feedstock comprising plastic waste and / or biomass.

[0039] In step a) of the process according to the present invention, benzene is provided. At least a portion of the benzene provided in step a) is manufactured by steps a1) to a6). Benzene manufactured by steps a1) to a6) has a recyclecontent of 100 %.

[0040] In the context of the present invention, the term “pyrolysis” relates to a thermal decomposition or degradation of a feedstock such as plastic waste under inert conditions and results in a gas, a liquid, and a solid char fraction. During the pyrolysis, the feedstock is converted in a pyrolysis unit into a great variety of chemicals including gases such as H2, Ci- to C4-alkanes, C2- to C4-alkenes, ethyne, propyne, 1 -butyne, pyrolysis oil having a boiling temperature of 25 °C to 500 °C or more and char. The direct products from such a pyrolysis are “pyrolysis gas” and solid products. The liquid product “pyrolysis oil” is then separated by condensation from the “pyrolysis gas”. In addition, water is formed during the pyrolysis which may be partially dispersed in the pyrolysis oil and may be partially contacted with the pyrolysis oil in a separate phase. The water formed during pyrolysis comprises various organic compounds and / or salts thereof which were also formed during the pyrolysis. The term “pyrolysis” includes slow pyrolysis, fast pyrolysis, flash catalysis and catalytic pyrolysis. These pyrolysis types differ regarding process temperature, heating rate, residence time, feed particle size, etc. resulting in different product quality. The pyrolysis unit may be operated adiabatically, isothermally, nonadiabatically, non-isothermally, or combinations thereof. The pyrolysis reactions of this disclosure may be carried out in a single stage or in multiple stages. For example, the pyrolysis unit can comprise two reactor vessels fluidly connected in series.

[0041] In the context of the present invention, "valued components” means "C6-C8 aromatic hydrocarbons” (benzene, toluene, 1 ,2-xylene, 1 ,3-xylene, 1 ,4-xylene, and ethylbenzene).

[0042] In the context of the present invention, the term "pyrolysis oil” is understood to mean any oil originating from the pyrolysis of plastic waste. The term "plastic waste” includes rubber waste such as end-of-life tires and feedstocks comprising plastic waste. The pyrolysis oil is obtained and / or obtainable from pyrolysis such plastic waste.

[0043] In the context of the present invention, the term "plastic waste” refers to any plastic material discarded after use, i.e. , the plastic material has reached the end of its useful life and is considered post-consumer waste. The plastic waste can be pure polymeric plastic waste, mixed plastic waste or film waste, including soiling, adhesive materials, fillers, residues etc. The plastic waste may have an oxygen content, a nitrogen content, sulfur content, halogen content and optionally also a heavy metal content. The plastic waste can originate from any plastic material containing source.

[0044] Accordingly, the term "plastic waste” includes industrial and domestic plastic waste and including used tires and agricultural and horticultural plastic material.

[0045] Typically, plastic waste is a mixture of different plastic materials, including hydrocarbon plastics, e.g., polyolefins such as polyethylene (HDPE, LDPE) and polypropylene, polystyrene, and copolymers thereof, etc., and polymers composed of carbon, hydrogen, and other elements such as chlorine, fluorine, oxygen, nitrogen, sulfur, silicone, etc., for example chlorinated plastics, such as polyvinylchloride (PVC), polyvinylidene chloride (PVDC), etc., nitrogencontaining plastics, such as polyamides (PA), polyurethanes (PU), acrylonitrile butadiene styrene (ABS), etc., oxy- gen-containing plastics such as polyesters, e.g., polyethylene terephthalate (PET), polycarbonate (PC), etc., silicones and / or sulfur bridges crosslinked rubbers.

[0046] Typically, the plastic material comprises additives, such as processing aids, plasticizers, flame retardants, pigments, light stabilizers, lubricants, impact modifiers, antistatic agents, antioxidants, etc. These additives may comprise elements other than carbon and hydrogen. For example, bromine is mainly found in connection to flame retardants. Heavy metal compounds may be used as lightfast pigments and / or stabilizers in plastics. Cadmium, zinc, and lead may be present in heat stabilizers and slip agents used in plastics manufacturing. The plastic waste can also contain residues. Residues in the sense of the invention are contaminants adhering to the plastic waste. The additives and residues are usually present in an amount of less than 50 wt.-%, preferably less than 30 wt.-%, more preferably less than 20 wt.-%, even more preferably less than 10 wt.-%, based on the total weight of the dry weight plastic. Examples of rubber waste (which is also considered "plastic waste” in the sense of the present invention) include end-of-life tires, rubber waste produced during manufacturing processes and discarded rubber containing products such as latex examining gloves and gaskets. End-of-life tires comprise further ingredients such as textiles and organic and inorganic additives which may be separated from the rubber portion of end-of-life tires prior to pyrolysis. Pyrolysis oils obtained by pyrolysis of (predominantly) end-of-life tires are also known as tire pyrolysis oils (TPO).

[0047] Examples of bio waste which can be comprised in "plastic waste” include green waste, food waste, human waste, manure, sewage, sewage sludge and slaughterhouse waste.

[0048] To obtain the pyrolysis oil according to the present invention, the feedstock is inserted into a pyrolysis reactor using a dosing unit such as a screw or an extruder or a rotary valve or a pneumatic conveyor or a liquid injector. The feedstock is optionally pre-heated in e.g., a heat exchanger prior to insertion into the pyrolysis reactor and / or subjected to a pre-pyrolysis at a temperature in the range of, for example, from about 200 °C to about 360 °C. Next, the feedstock is heated in the pyrolysis reactor to a temperature in the range of from about 350 °C to about 900 °C, more preferably in the range of from 400 °C to about 550 °C, and a pressure in the range of from about 0.5 bar to about 2 bar(abs), more preferably in the range of from 0.9 bar to about 1.5 bar(abs). The pyrolysis reactor is preferably selected from the group comprising fluidized bed reactors, moving bed reactors, entrained flow reactors, screw reactors, extruders, stirred tank reactors and rotary kiln reactor. Preferably, the pyrolysis is performed in the pyrolysis reactor under an inert atmosphere exempt of oxygen or air.

[0049] Pyrolysis processes as such are known. They are described, e.g., in EP 0713906 A1 and WO 95 / 03375 A1. Suitable pyrolysis oils are also commercially available. The pyrolysis oil is typically a liquid at 15 °C or a wax at said temperature. "Liquid at 15 °C” in the terms of the present invention means that the pyrolysis oil has a density of at most 1 .3 g / ml, e.g., a density in the range from 0.65 to 0.98 g / ml, at 15 °C and 1013 mbar, as determined according to DIN EN ISO 12185.

[0050] The amount of 06-08 aromatic hydrocarbons formed by pyrolysis reaction of the above-described feedstocks can be increased for example in the presence of a suitable catalyst. Another suitable method for increasing the amount of 06-08 aromatic hydrocarbons is disclosed in EP 3744814 A1 : the pyrolysis gas obtained by a pyrolysis reaction of above-described feedstocks is then subjected to a thermo-catalytic treatment at about 450 °C to about 600 °C (at least 50 °C lower than the pyrolysis reaction temperature applied in the first step) in the presence of an "aromatization catalyst” such as ZSM-5, ZSM-11, ZSM-35, ZSM-23, ferrierite, zeolite beta, zeolite Y, zeolite X, mordenite, zeolite A, IM-5, SSZ-20, SSZ-55, MCM-22, TNU-9, metal treated, exchanged or impregnated and combinations of the aforementioned catalysts and post-treatments. Other suitable catalysts comprise sand and alumina. Also, combinations of the aforementioned catalysts can be used for this purpose. The amount of C6-C8 aromatic hydrocarbons in a pyrolysis oil can also be increased by reforming said pyrolysis oil or mixture of pyrolysis oils, for example by a catalytic reforming reaction. Such reforming reactions are for example disclosed in https: / / www.e-education.psu.edu / fsc432 / content / catalyic-reforming-processes and can be adapted, if necessary, by the skilled person.

[0051] A liquid stream S1 comprising a pyrolysis oil or mixture of pyrolysis oils, the liquid stream S1 further comprising C6-C8 aromatic hydrocarbons, organic compounds comprising at least one heteroatom and compounds having C-C double and / or C-C triple bonds can also be manufactured by a pyrolysis of plastic waste stream comprising polystyrene (Maafa, I.M. Pyrolysis of Polystyrene Waste: A Review. Polymers 2021, 13, 225. https: / / doi.org / 10.3390 / polym13020225).

[0052] The liquid stream S1 , more preferably the at least one pyrolysis oil comprised in the liquid stream S1 comprises C6-C8 aromatic hydrocarbons in an amount of at least 5 wt.-%, or at least 10 wt.-% or at least 15 wt.-% or at least 20 wt.-% or at least 25 wt.-% or at least 30 wt.-% or at least 35 wt.-% or at least 40 wt.-% or at least 45 wt.-% or at least 50 wt.-% or at least 55 wt.-% or at least 60 wt.-% or at least 70 wt.-% or at least 80 wt.-% based on the total amount of hydrocarbons comprised in the liquid stream S1. Preferably, C6-C8 aromatic hydrocarbons are selected from the group consisting of benzene, toluene, 1 ,2-xylene, 1 ,3-xylene, 1 ,4-xylene, and ethylbenzene.

[0053] The at least one pyrolysis oil comprised in the liquid stream S1 preferably further has a bromine number of about 2 g Br2 / 100g to about 150 g E / IOOg (determined by ASTM 1159) and / or a C5 hydrocarbon content of about 0.03 wt.-% to about 12.2 wt.-% (determined by ASTM D 5134) and / or a naphthalene content of about 0.5 wt.-% to about 18.4 wt.-% (determined by ASTM D 5134) and / or a styrene content of about 0.02 wt.-% to about 29.5 wt.-% (determined by ASTM D 5134) and / or a toluene content of about 4.3 wt.-% to about 71.5 wt.-% (determined by ASTM D 5134). Such pyrolysis oils are particularly suited for the method and the chemical plant according to the present invention.

[0054] Optionally, the pyrolysis oil or mixture of pyrolysis oils is subjected to one or more methods selected from filtration, centrifugation, adsorption, washing, extraction before used as liquid stream S1 in the method according to the present invention and / or as feedstock for the chemical plant according to the present invention. Such optional pretreatment methods are for example described in WO 2021 / 224287 A1, WO 2023 / 061834 A1, EP 0713906 A1 and WO 95 / 03375 A1 which are incorporated herein by reference. A skilled person knows how and in which cases to use pre-treatment methods disclosed in said documents and comparable pre-treatment methods disclosed elsewhere.

[0055] The liquid stream S1 comprises at least one pyrolysis oil manufactured by the above-described feedstocks and the above-described methods or mixtures of such pyrolysis oils The liquid stream S1 comprises C6-C8 aromatic hydrocarbons, organic compounds comprising at least one heteroatom and compounds having C-C double bonds (olefins, dienes) and / or C-C triple bonds which are contributed by the at least one pyrolysis oil and / or further liquid hydrocarbon feedstocks optionally comprised in the liquid stream S1. Examples of such further liquid hydrocarbon feedstocks are given further below.

[0056] A liquid stream S1 comprising at least one pyrolysis oil, the liquid stream S1 further comprising C6-C8 aromatic hydrocarbons, organic compounds comprising at least one heteroatom and compounds having C-C double and / or C-C triple bonds is provided in step a1) of the process according to the present invention (Figure 2 and 3 show steps a1) to a6)). The liquid stream S1 may further comprise at least one further liquid hydrocarbon feedstock which comprises C6-C8 aromatic hydrocarbons which is different from pyrolysis oils obtained by pyrolysis oil of plastic waste. Suitable examples of such further liquid hydrocarbon feedstocks comprise pyrolysis gasoline and coke-oven light oil (CAS number: 65996-78-3). Pyrolysis gasoline is a side product obtained or obtainable from hydrocarbon feedstocks by steam cracking such as steam cracking of naphtha. Pyrolysis gasoline and the manufacture thereof are known in the art. Pyrolysis gasoline comprises C6-C8 aromatic hydrocarbons. Coke-oven light oil can be obtained by extraction from the gas evolved in the high temperature (for example, greater than 700°C) destructive distillation of coal. It is primarily composed of benzene, toluene, and xylenes and may contain other minor hydrocarbon constituents.

[0057] Such further liquid hydrocarbon feedstock (in case more than one liquid hydrocarbon feedstocks the sum of all liquid hydrocarbon feedstocks) can be comprised in the liquid stream S1 for example in a quantity of 0 wt.-%, 5 wt.-%, 10 wt.-%, 15 wt.-%, 20 wt.-%, 25 wt.-%, 30 wt.-%, 35 wt.-%, 40 wt.-%, 45 wt.-%, 50 wt.-%, 55 wt.-%, 60 wt.-%, 65 wt.-%, 70 wt.-%, 75 wt.-%, 80 wt.-% or more with the proviso that at least 2 wt.-% of the liquid stream S1 are comprised of at least one pyrolysis oil manufactured by pyrolysis of plastic waste.

[0058] A stream S2 comprising H2 is provided in step a2) of the process according to the present invention. The stream S2 can consist essentially of H2 or comprise H2 together with at least one other gas. Preferably the H2 content of the stream S2 is higher than about 50 Vol.-%, more preferably higher than about 80 Vol.-% and most preferably higher than about 95 Vol.-%. This minimizes the amount of purge-gas needed to keep the H2 partial pressure high and saves H2. A high H2 partial pressure promotes the catalyst activity and allows low reaction temperatures. The advantage of low reaction temperatures is that undesired polymerization of components in stream S2 is suppressed. Such polymerization results in undesired fouling during processing.

[0059] Hydrogen (H2) used in the method and system according to the present invention is preferably "green hydrogen” which is generated for example by electrolysis of water using electricity generated from renewable energy sources (e.g., solar energy, wind energy, tidal energy, and nuclear energy) and / or low-carbon energy sources and / or a methane pyrolysis, preferably a methane pyrolysis using at least partially methane from a renewable source. Methane from a renewable source comprises biomethane. Optionally, at least a portion of the hydrogen used in the method according to the present invention is hydrogen formed during the pyrolysis reaction and separated from the volatile pyrolysis reaction products.

[0060] In process step a3) according to the invention, compounds having C-C double bonds and / or C-C triple bonds present in liquid stream S1 are hydrogenated in a first hydroprocessing unit HU1 in the presence of stream S2. Thereby a liquid stream S3 is formed which leaves the first hydroprocessing unit HU1 . Optionally and preferably, a portion of the liquid stream S3 is separated from liquid stream S3 and fed into the first hydroprocessing unit HU1 as a liquid recycle S3' together with liquid stream S1 and stream S2.

[0061] The first hydroprocessing unit HU1 comprising at least one stage, in which C-C double bonds and / or C-C triple bonds present in liquid stream S1 are hydrogenated. The first hydroprocessing unit HU1 is preferably a three-phase reactor, more preferably a three-phase reactor with a fixed catalyst bed. Said three-phase reactor is most preferably operated in trickling mode or pulse flow mode. Said fixed catalyst bed preferably comprises at least one catalyst which is used in at least one stage of the first hydroprocessing unit HU1 . The first hydroprocessing unit HU1 can also comprise two or more of such reactors or a single reactor can comprise one or more beds, each bed comprising one or more catalysts.

[0062] Preferably, the first hydroprocessing unit HU1 comprises one single reactor having one single catalyst bed. Thereby, the geometric shape of the first hydroprocessing unit HU1 is minimized, and a cost-efficient reactor design is assured.

[0063] The at least one hydrogenation reactor of the first hydroprocessing unit HU1 is preferably designed to function in trickling mode or pulse flow mode where the gaseous phase (gaseous stream S2 comprising H2) is continuous or semi-continuous and the liquid phase (liquid stream S1) flows along the solids, mainly along the surface of the at least one catalyst and thereby wetting them efficiently.

[0064] The process temperature in the at least one hydrogenation reactor of the first hydroprocessing unit HU1 depends on catalyst type used and the degree of activity of the catalyst. The process temperature preferably ranges from about 60 °C to about 250 °C, more preferably from about 60 °C to about 200 °C and most preferably from about 80 °C to about 120 °C. The deactivation of the catalyst can optionally be compensated by raising the process temperature.

[0065] The hydrogen pressure preferably ranges from about 1.0 to about 10 MPa abs. in the in the at least one hydrogenation reactor of the first hydroprocessing unit HU1 .

[0066] The weight hourly space velocity (WHSV) of the liquid stream S1 excluding the optional liquid recycle stream S3' preferably ranges from about 0.1 t / (m3Kat / h) to about 5 t / (m3Kat h), more preferably from about 0.5 t / (m3Kat / h) to about 1.0 t / (m3Kat / h). The chosen process conditions allow to maintain the liquid stream S1 in the liquid stage during step a3). The amount of hydrogen comprised in the first hydroprocessing unit HU1 is sufficient to hydrogenate undesired C-C double bonds (olefins, dienes) and C-C triple bonds present in the liquid stream S1 but insufficient to hydrogenate the desired C6-C8 aromatic hydrocarbons also present in the liquid stream S1 by a ring hydrogenation.

[0067] The dilution of liquid stream S1 by an optional liquid recycle stream S3' further reduces undesired fouling by polymerization inside the first hydroprocessing unit HU1. Furthermore, the temperature inside the first hydroprocessing unit HU1 can be better controlled when diluting the liquid stream S1 with an optional liquid recycle stream S3'.

[0068] The ratio "liquid recycle stream S3' : liquid stream S1” preferably ranges between about 2:1 and about 20:1, more preferably between about 8:1 and about 15:1.

[0069] Preferably, the liquid stream S1 and the optional recycle liquid stream S3' are mixed before entering the at least one reactor of the first hydroprocessing unit HU1 .

[0070] Preferably, suitable catalysts for the first hydroprocessing unit HU1 comprise at least one catalytically active metal selected from the element of groups 8 to 12 of the periodic table, more preferably the at least one catalytically active metal is selected from the group comprising or consisting of nickel, palladium, platinum, rhodium and most preferably is palladium. In case palladium is the catalytically active metal, the catalyst comprises palladium in an amount, calculated as elemental palladium, in the range of from about 0.01 wt.-% to about 5 wt.-%, more preferably from about 0.1 wt.-% to about 1 wt.-%, most preferably from 0.15 to 0.8 wt-%, based on the total weight of the catalyst.

[0071] Suitable catalysts further comprise a support, preferably an inorganic support such as silica, alumina, silica-aluminas, silica-alumina phosphates, magnesium oxide, clays, carbon, and mixtures thereof. The supports may also comprise support-dopants such as zirconium dioxide, cerium dioxide, titanium dioxide, and mixtures thereof. "Silica-aluminas” also comprise zeolites.

[0072] Preferably, the catalysts for the first hydroprocessing unit HU1 further comprises a promoter, the promoter more preferably being one or more of element of the groups 10 and 11 of the periodic table of elements, preferably one or more of copper, gold, silver, and platinum, more preferably one or more of silver and platinum, most preferably silver.

[0073] Preferably, the atomic ratio of the at least one catalytically active element of groups 8 to 12 of the periodic table, more preferably of the group comprising or consisting of nickel, palladium, platinum, rhodium, and most preferably of palladium, relative to the promoter is in the range of from 0.1 :1 to 10:1, more preferably from 2:1 to 7:1, more preferably from 2.5:1 to 6:1. Most preferably, the catalysts for the first hydroprocessing unit HU1 comprises palladium supported on a support material, preferably a support material as defined in the foregoing, wherein the support material is more preferably alumina or carbon, most preferably alumina.

[0074] In the context of the present invention, the at least one catalyst for the first hydroprocessing unit HU1 preferably is in the form of extrudates, pellets, rings, spherical particles or spheres, more preferably spherical particles or extrudates.

[0075] The particle size means here particle size distribution, which is measured for example by sieve methods, laser diffraction methods or other methods known in the art. A catalyst having a desired particle size and optionally desired shape may be manufactured and used.

[0076] The catalysts for the first hydroprocessing unit HU 1 , most preferably comprising or consisting of palladium is preferably activated under flow of hydrogen (for example GHSV = 1000 / h) at about 50 °C to about 130 °C, for example for about 6 h to about 24 h such as about 12 h, preferably at atmospheric condition. Upon catalyst reduction in larger reactor, hydrogen can be diluted by nitrogen to avoid excess temperature.

[0077] The height and diameter of the at least one catalyst bed is chosen on reaction kinetics and optimal I iquid / gas flowpattern and pressure drop. The at least one catalyst bed may consist of one or more layers of different solid absorption materials, or / and one or different hydrogenation catalysts. The catalyst layers in the at least one catalyst bed may differ from each other by particle size or shape or activity or active sites of material. Inert particles may be used above and below each bed to improve fluid distribution in case more than one catalyst bed is used.

[0078] In case the at least one hydrogenation reactor in the first hydroprocessing unit HU1 has at least two stages, the catalyst preferably has a different particle size in at least two stages and / or optionally different shape in the at least two stages.

[0079] The hydrogenation reaction is an exothermic reaction and therefore each reaction stage may optionally be cooled.

[0080] Preferably, at least a portion of the liquid stream S3 is fed into the first hydroprocessing unit HU1 at least for a second time as recycle stream S3'. In this case, the first hydroprocessing unit HU1 preferably also comprises a recycling unit in which the desired portion of the optional recycle stream S3' can be separated from liquid stream S3. The liquid stream S1 is diluted before entering the first hydroprocessing unit HU1 with optional recycle stream S3' and thereby, undesired fouling caused by polymerization of compounds having C-C double bonds (olefins, dienes) and compounds having C-C triple bonds present in liquid stream S1 is reduced. The reactor inlet temperature of the first hydroprocessing unit HU1 is optionally and preferably adjusted by mixing warm liquid recycle stream S3' and cooled down liquid recycle stream S3' from the outlet of the at least one reactor of the first hydroprocessing unit HU1 with the liquid stream S1 to adjust the desired reactor inlet temperature. This optional and preferred concept avoids the contact with heat-exchange surfaces and thereby avoids undesired fouling of the heat exchanger surfaces and whereby the undesired fouling also causes reduction of heat-transfer inside the heat exchanger which is avoided by the optional and preferred concept. If the outlet-stream of the at least one reactor of the first hydroprocessing unit HU1 is not warm enough, then the polymerizing stable stream S3 is heated up by a heat-exchanger to adjust the necessary temperature.

[0081] About 90 % or more, preferably more than 95 % and most preferably 99 % of the dienes present in the liquid stream S1 are converted in step a3) of the process according to the present invention.

[0082] To maintain a high H2 partial pressure in the first hydroprocessing unit HU 1 , preferably the first hydroprocessing unit HU 1 is operated with an off-gas stream S2', more preferably, when the H2 concentration in stream S2 is lower than 99.9 Vol.-%, to avoid accumulation of inert gaseous components such as N2, CH4, and C2H6 in stream S2. The ratio "H2 content in the fresh H2 feed stream S2 : chemical H2 consumption caused by the hydrogenation reaction(s) in the first hydroprocessing unit HU1” preferably ranges from about 1 :1 to about 5:1 , more preferably from about 1 :1 to about 3: 1 and most preferably from about 1 : 1 to about 2: 1.

[0083] The total pressure at the outlet of the at least one reactor in the first hydroprocessing unit HU 1 preferably ranges from about 5 bar (abs.) to about 60 bar (abs.), more preferably from about 10 bar (abs.) to about 40 bar (abs) and most preferably from about 20 bar (abs.) to about 40 bar(abs).

[0084] Next, in step a4) of the process according to the present invention at least a portion of the liquid stream S3 is subjected to a distillation in a distillation unit DU at an elevated temperature for separating the at least a portion or the remaining portion of liquid stream S3 into a valued components (mononuclear aromatic components: benzene, toluene, ethylbenzene and xylenes, i.e., C6-C8 aromatic hydrocarbons) enriched stream S4 and a liquid stream S5 having a higher boiling point range than the stream S4. "Remaining portion of liquid stream S3” means the remaining portion of stream S3 after stream S3' was optionally separated therefrom in step (iii). Stream S4 is also denoted "lights stream” and stream S5 "heavies stream”. The stream S4 comprises C6-C8 aromatic hydrocarbons and at least a portion of the organic compounds comprising at least one heteroatom which were comprised in the liquid stream S3. The stream S4 preferably has a final boiling point of about 100 °C to about 220 °C, more preferably about 120 °C to about 190 °C and most preferably about 150 °C to about 170 °C.

[0085] The liquid stream S5 preferably has the same final boiling point as the liquid stream S1. The liquid stream S5 can be then for example converted in at least one gasifier and / or partial oxidation reaction unit into syngas which is predominantly a mixture of H2 and CO. Such partial oxidation reactions are known in the art and are for example disclosed in WO 2022 / 200532 A1 which is incorporated herein by reference. The skilled person can select suitable reactors and reaction conditions to convert the liquid stream S5 into syngas by a partial oxidation reaction and / or gasification.

[0086] Final boiling points of streams S1 , S3, S4, S5 and S6 are preferably measured by the method(s) described in ASTM D86, ASTM D7169 and for very high boiling liquids also by ASTM D7182.

[0087] The distillation unit DU comprises at least one distillation column, at least one thin film evaporator or a combination thereof. The distillation unit DU is downstream of and fluidically connected to the first hydroprocessing unit HU1. Preferably, the distillation unit DU comprises or consists of one distillation column.

[0088] The distillation is carried out at a temperature in the range of about 0 °C to about 600 °C, more preferably from about 20 °C to about 400 °C, most preferably from about 80 °C to about 250 °C (the temperature ranges refer to atmospheric pressure of 1.013 bar). The corresponding operating pressure of the at least one distillation column preferably ranges from about 0.001 bar to about 4 bar (abs), more preferably from about 0.001 bar to about 2.0 bar (abs), most preferably from about 0.9 bar to about 1.8 bar (abs). The temperature is adjusted accordingly in case the pressure is A 1.013 bar.

[0089] Optionally, the distillation unit DU comprises at least one thin-film evaporator. In thin-film evaporators the medium to be evaporated or the solution to be concentrated by evaporation, respectively, is applied to the evaporator area as a thin film. Thereby, a short contact time with the heating surface is feasible and thermally unstable liquids and substances, respectively, can be evaporated in such thin-film evaporators. Furthermore, thin-film evaporators can be used for separation tasks if the product accumulating as a residue has poor flow properties and / or is prone to agglutinations. Thin-film evaporation processes are based on the principle of simple distillation according to which the separating capacity of said type of evaporator is limited. Suitable thin-film evaporators are available in various designs, for example as falling-film evaporators or as rotary evaporators.

[0090] Next, the valued components containing stream S4 is converted during step a5) of the process according to the present invention in a second hydroprocessing unit HU2 into valued components containing purified stream S6 and a gaseous stream S6'. The valued components containing purified stream S6 is depleted in heteroatoms such as nitrogen, oxygen, halogens (fluorine, chlorine, bromine, iodine), and sulfur in respect to the valued components containing stream S4 by a hydrotreatment with a gaseous stream S4' which comprises hydrogen (H2) in the second hydroprocessing unit HU2. Optionally, the off-gas stream S2’ can be fed to the second hydroprocessing unit HU2. In this case, the stream S4’ balances the hydrogen demand of the second hydroprocessing unit HU2. The heteroatoms leave the second hydroprocessing unit HU2 in form of their respective hydrogenated species as gaseous stream S6'.

[0091] The respective hydrogenated species of heteroatoms comprise NH3, H2O, H(Hal) (HF, HOI, HBr, HI), and H2S. NH3 and H(Hal) may form salts of type NH^al (NH4F, NH4CI, N H4Br, NH4I) and NH3 and H2S may form the salt NH4SH. Such salts may be formed already in the gas phase in the second hydroprocessing unit HU2 and can then form undesired deposits on metal surfaces by resublimation when stream S6 is cooled down.

[0092] NH4CI, NH4F, NH4Br, NH4I and NH4SH of which at least one may be formed mainly in the second hydroprocessing unit HU2 (a minor portion may also be formed in the first hydroporocessing unit HU1) are preferably removed from the second hydroprocessing unit HU2 by water. More preferably, NH4F, NH4CI, NH4Br, NH4I and / or the respective cations and anions are removed quantitatively with water and NH4SH and / or the respective cation and anion is / are partly removed from the second hydroprocessing unit HU2 with a water stream (not shown in Figures 2 and 3).

[0093] Accordingly, the reactions in the second hydroprocessing unit HU2 comprise hydrodenitrogenation, hydrodeoxygenation, hydrodehalogenation and hydrodesulfurization. Furthermore, the reactions comprise hydrodemetallization and, preferably, also hydrogenation of the remaining C-C double bonds (olefins and dienes) and C-C triple bonds whereas the conjugated C-C bonds in C6-C8 aromatic hydrocarbons present in gaseous stream S4 are essentially not hydrogenated by a ring hydrogenation in the second hydroprocessing unit HU2.

[0094] The second hydroprocessing unit HU2 is downstream of and fluidically connected to the distillation unit DU.

[0095] The second hydroprocessing unit HU2 may be any vessel configured to contain the hydroprocessing catalyst disclosed herein. The vessel is preferably configured for gas phase operation. The second hydroprocessing unit HU2 may include one or more beds of the hydroprocessing catalyst, preferably in fixed bed configuration. The second hydroprocessing unit HU2 can be operated adiabatically, isothermally, non-adiabatically, non-isothermally, or combinations thereof. The second hydroprocessing unit HU2 may comprises more than one vessel. Each of such vessels is considered a hydrogenation reactor.

[0096] The valued components containing stream S4 can be contacted with the hydroprocessing catalyst in upward flow, downward flow, radial flow, or combinations thereof, with or without a staged addition of the gaseous stream S4, the gaseous stream S2' or combinations thereof.

[0097] Preferably, heteroatoms comprising halogens (such as chlorine), nitrogen, oxygen, and sulfur are removed from the valued components containing stream S4 in the second hydroprocessing unit HU2. Such heteroatoms are separated from the organic residues by the hydrotreatment conditions for examples as HF, HCI, HBr, NH3, H2O and H2S and the separated heteroatoms are replaced by hydrogen atoms in the organic residue. In addition, remaining olefins and / or dienes in the valued components containing stream S4 which were not converted into saturated hydrocarbons in the first hydrogenation unit HU1 are converted to saturated hydrocarbons in the second hydroprocessing unit HU2.

[0098] The hydroprocessing catalyst may be any catalyst used for hydrogenation of olefins, dienes and heteroatom hydrogenation (e.g., commercially available hydroprocessing catalysts). Suitable hydroprocessing catalysts for this pur- pose comprise molybdenum catalysts (Mo catalysts), cobalt-molybdenum catalysts (Co-Mo catalysts), nickelmolybdenum catalysts (Ni-Mo catalysts), tungsten-molybdenum catalysts (W-Mo catalysts), cobalt-molybdenum oxides, nickel-molybdenum oxides, tungsten-molybdenum oxides, cobalt-molybdenum sulfides, nickel-molybdenum sulfides, tungsten-molybdenum sulfides, molybdenum sulfides. Suitable catalysts further comprise a support, preferably an inorganic support such as silica, alumina, silica-aluminas, magnesia, clays, and mixtures thereof. Further suitable hydroprocessing catalysts are for example zeolites comprising one or more metals. More than one of the aforementioned hydroprocessing catalysts can be used together in the second hydroprocessing unit HU2.

[0099] The height and diameter of the at least one catalyst bed is chosen on reaction kinetics and optimal I iquid / gas flowpattern and pressure drop. The at least one catalyst bed may consist of one or more layers of different solid absorption materials, or / and one or different hydrogenation catalysts. The catalyst layers in the at least one catalyst bed may differ from each other by particle size or shape or activity or active sites of material. Inert particles may be used above and below each bed to improve fluid distribution in case more than one catalyst bed is used.

[0100] In the context of the present invention, the catalysts for the second hydroprocessing unit HU2 preferably is in the form of extrudates, pellets, rings, spherical particles or spheres, more preferably spherical particles or extrudates.

[0101] In case the at least one hydrogenation reactor (vessel) in the second hydroprocessing unit HU2 has at least two stages, the catalyst preferably has different particle size in at least two stages and / or optionally different shape in the at least two stages.

[0102] The particle size means here particle size distribution, which is measured for example by sieve methods, laser diffraction methods or other methods known in the art. A catalyst having a desired particle size and optionally desired shape may be manufactured and used.

[0103] The hydrogenation reaction is an exothermic reaction and therefore each reaction stage may optionally be cooled.

[0104] The second hydroprocessing unit HU2 can be operated at various process conditions. For example, the valued components containing stream S4 is contacted with the hydroprocessing catalyst preferably in the presence of a gaseous stream S4' which comprises hydrogen and / or an optional internal recycle-gas stream S6" at a temperature of preferably from about 200 °C to about 400 °C, more preferably from about 240 °C to about 380 °C and most preferably from about 260 °C to about 360 °C. Optionally, the gaseous stream S4' further comprises at least a portion of the stream S2'. The presence of a gaseous stream S4' is preferred to balance the amount of hydrogen which is consumed or otherwise lost in the second hydroprocessing unit HU2. The aspect of the present invention further comprising the optional internal recycle-gas stream S6" is shown in Figure 3. The temperature in the second hydroprocessing unit HU2 can be attained by using a pre-heated valued components containing stream S4 and / or a heat integration of the valued components containing stream S4 with the valued components containing purified stream S6 using at least one heat exchanger.

[0105] The pressure during hydroprocessing in the second hydroprocessing unit HU2 preferably ranges from about 1 bar to about 200 bar, more preferably from about 10 bar to about 150 bar and most preferably from 20 bar to 60 bar.

[0106] The weight hourly space velocity (WHSV) of the valued components containing stream S4 preferably ranges from about 0.1 t / (m3Kat 'h) to about 5 t / (m3Kafh), more preferably from about 0.5 t / (m3Kat / h) to about 1.0 t / (m3Kat / h).

[0107] In another, aspect of the present invention, the second hydroprocessing unit HU2 is operated with addition of an optional recycle-gas stream S6" which means that the hydrogen inside the second hydroprocessing unit HU2 which is not consumed by hydrogenation reactions is separated from stream S6 and a stream S6' and then fed again into the second hydroprocessing unit HU2 as recycle-gas stream S6". The remaining non hydrogen portion of the off-gas stream S2" and volatile compounds formed by hydrogenation reactions with the stream S6 leave the second hydroprocessing unit HU2 as stream S6'. This aspect is shown in Figure 3.

[0108] The addition of an optional recycle-gas stream S6" as described above is also beneficial to evaporate the stream S4 and keep it in the gas phase. Furthermore, the optional recycle-gas stream S6" dilutes the stream S4. This limits the adiabatic temperature increase by the hydrogenation reactions and effects a high H2 partial pressure which is beneficial for the hydrogenation activity of the catalyst.

[0109] The ratio “recycle-gas stream S6" : value product containing stream S4” is preferably between about 300 Nm3 / t to about 2000 Nm3 / t, more preferably between 500 Nm3 / t to about 800 Nm3 / t.

[0110] More preferably, the stream S6, or a portion thereof is not recycled (inserted again) into the first hydroprocessing unit HU1.

[0111] There is no need to recycle a portion of the stream S6 into the first hydroprocessing unit HU 1 because stream S4 is stable enough in respect to undesired polymerization and therefore, stream S4 can be vaporized and heated up for insertion into the second hydroprocessing unit HU2. This enables to build the first hydroprocessing unit HU 1 (optional liquid recycle stream S3' included) and the second hydroprocessing unit HU2 (recycle-gas included) for “once through capacity” which means that the liquid stream S1 (and the streams manufactured thereof by conversion in the individual process units) only flow(s) once through the first hydroprocessing unit HU 1 (which it leaves as stream S3), the distillation unit DU (stream S5 which then enters HU2) and then leaves the second hydroprocessing unit HU2, converted, as stream S6. Next, in step a6) of the process according to the present invention, the valued components containing purified stream S6 is separated in at least one aromatic hydrocarbon extraction unit AEU into a stream S7' which is enriched in benzene, a stream S7" which is enriched in toluene, a stream S7" which is enriched in C8 aromatic hydrocarbons (ethylbenzene, 1,2-xylene, 1 ,3-xylene, 1,4-xylene) and a stream S8 which is depleted in the desired C6-C8 aromatic hydrocarbons.

[0112] The at least one aromatic hydrocarbon extraction unit AEU is downstream of and fluidically connected to the second hydroprocessing unit HU2 and thereby enables a flow of the valued components containing stream S6 from the exit of the second hydroprocessing unit HU2 into the at least one aromatic hydrocarbon extraction unit AEU.

[0113] The at least one aromatic hydrocarbon extraction unit AEU can be any unit operation suitable to separate the valued components containing stream S6 into a stream S7' which is enriched in benzene, a stream S7" which is enriched in toluene and a stream S7" which is enriched in C8 aromatic hydrocarbons (ethylbenzene, 1,2-xylene, 1 ,3-xylene, 1,4- xylene). For example, the at least one aromatic hydrocarbon extraction unit AEU can comprise at least one selective adsorption unit operation, at least one selective absorption unit operation, at least one extractive distillation unit operation, at least one solvent extraction followed by distillation and combinations thereof.

[0114] Suitable aromatic hydrocarbon extraction units AEU are commercially available, for example the Morphylane® extractive distillation process by Uhde. For example, the stream S6 is first split into a C7. fraction and a Cs+ fraction. Next, the C7. fraction is sent to an extractive distillation stage in which a stream S7' comprising benzene and a stream S7" comprising toluene are separated from the C7--non-aromatics in stream S6. The Cs+ fraction of stream S6 is sent directly to a 1,4-xylene loop without the xylenes and ethylbenzene being extracted.

[0115] The stream S7' preferably comprises at least 90 wt.-% benzene, more preferably at least 95 wt.-% benzene and most preferably at least 99 wt.-% benzene. Stream S7' is suited for providing the benzene in step a) of the process according to the present invention.

[0116] The stream S8 is suited as a feedstock for cracking processes such as (fluid) catalytic cracking, thermal cracking and steam cracking. The main reaction products from such cracking processes comprise ethylene, propylene, butylene isomers, butadiene, and pyrolysis gasoline. At least a portion of the pyrolysis gasoline can be utilized in stream S1 together with pyrolysis oils obtained by pyrolysis of plastic waste as a co-feedstock. Such pyrolysis gasoline comprises C6-C8 aromatic hydrocarbons.

[0117] The individual units of the chemical plant for separating C6-C8 aromatic hydrocarbons from a liquid stream comprising at least one pyrolysis oil and their connectivity are shown in Figure 2 and will be described below: The chemical plant for separating C6-C8 aromatic hydrocarbons from a liquid stream comprising at least one pyrolysis oils, comprises at least one first hydroprocessing unit HU1 , the at least one first hydroprocessing unit HU1 comprising at least one inlet and at least one outlet, optionally a recycle unit downstream of and fluidically connected to the inlet and the outlet of the first hydroprocessing unit HU1 , at least one distillation unit DU downstream of and fluidically connected to the outlet of the first hydroprocessing unit HU1 , the at least one distillation unit having a bottom outlet BO and a head outlet HO, a second hydroprocessing unit HU2 downstream of and fluidically connected to the head outlet HO of the at least one distillation unit DU, at least one aromatic hydrocarbon extraction unit AEU which is downstream and fluidically connected to the second hydroprocessing unit HU2. The heavies stream (stream S5) leaves the distillation unit DU through the bottom outlet BO and wherein the lights stream (stream S4) leaves the distillation unit DU through the head outlet HO.

[0118] A liquid stream S1 of a pyrolysis oil or mixture of pyrolysis oils, the liquid stream S1 comprising 06-08 aromatic hydrocarbons, organic compounds comprising at least one heteroatom and compounds having 0-0 double and / or 0-0 triple bonds is converted in the first hydroprocessing unit HU1 with a stream S2. The remaining portion of stream S2 leaves the first hydroprocessing unit HU1 as stream S2'. The liquid stream S1 is converted in the first hydroprocessing unit HU1 into the stream S3. A portion of the stream S3 is optionally recycled as stream S3' which is mixed with stream S1 and inserted into the first hydroprocessing unit HU1.

[0119] The stream S3 is separated in the distillation unit DU into a stream S4 ("lights stream”) and a stream S5 ("heavies stream”).

[0120] Optionally, the gaseous stream S4' further comprises at least a portion of the off-gas stream S2'. Gaseous stream S4' is required to balance the amount of hydrogen which is consumed or otherwise lost in the second hydroprocessing unit HU2.

[0121] The stream S4 is converted in the second hydroprocessing unit HU2 with the gaseous stream S4’ and optionally in addition with off-gas stream S2’ into a stream S6. In this case, the gaseous stream S4’ balances the hydrogen demand of second hydroprocessing unit HU2. The remaining non hydrogen portion of the off-gas stream S2" and volatile compounds formed by hydrogenation reactions with the stream S6 leave the second hydroprocessing unit HU2 as stream S6'.

[0122] The stream S6 enters an aromatic hydrocarbon extraction unit AEU in which stream S6 is separated into stream S7', stream S7", stream S7'" and stream S8. Stream S7' comprises benzene and is suited to provide benzene in step a) of the process according to the present invention. The specifications of all units and streams are described above in the "process” section for process steps a1) to a6) and are preferably the same in case of the process according of the present invention and the chemical plant according to the present invention.

[0123] Preferably, at least 2.5 wt.-%, more preferably at least 5.0 wt.-% and most preferably at least 7.5 wt.% of the benzene provided in step a) is benzene manufactured from a non-fossil feedstock.

[0124] Preferably, at least 2.5 wt.-%, more preferably at least 5.0 wt.-% and most preferably at least 7.5 wt.% of the benzene provided in step a) is manufactured by steps a1) to a6).

[0125] Benzene can be for example separated from fossil feedstocks such as pyrolysis gasoline and coke-oven light oil which is described above.

[0126] Preferably, the plastic waste used to manufacture the at least one pyrolysis oil provided in step a1) comprises poly(azepan-2-one) and / or poly[imino(1,6-dioxohexamethylene) iminohexamethylene]. In case poly(azepan-2-one) is manufactured by the process according to the present invention and the plastic waste comprises poly(azepan-2- one), a closed recycling loop for poly(azepan-2-one) is achieved. In case poly[imino(1,6-dioxohexamethylene) iminohexamethylene] is manufactured by the process according to the present invention and the plastic waste comprises poly[imino(1,6-dioxohexamethylene) iminohexamethylene], a closed recycling loop for poly[imino(1 ,6- dioxohexamethylene) iminohexamethylene] is achieved.

[0127] In step b) of the process according to the present invention, hydrogen is provided. Hydrogen from standard sources used in chemical plants can be used. Preferably, hydrogen (H2) used in the step b) of the process according to the present invention is "green hydrogen” which is generated for example by electrolysis of water using electricity generated from renewable energy sources (e.g., solar energy, wind energy, tidal energy, and nuclear energy) and / or low- carbon energy sources and / or a methane pyrolysis, preferably a methane pyrolysis using at least partially methane from a renewable source. Methane from a renewable source comprises biomethane. Optionally, at least a portion of the hydrogen is hydrogen formed during the pyrolysis reaction and separated from the volatile pyrolysis reaction products.

[0128] In step c) of the process according to the present invention, the benzene provided in step a) and hydrogen provided in step b) are contacted with each other in the presence of a first heterogeneous catalyst whereby cyclohexane is formed.

[0129] Cyclohexane can be manufactured by a hydrogenation reaction from benzene by a catalytic hydrogenation reaction in the presence of hydrogen. Suitable catalysts comprise nickel, platinum, or palladium on a support such as alumina, or a Raney nickel catalyst. The process temperature is about 300 °C or less at a pressure of about 20 MPa to about 30 MPa. Further details are for example disclosed in M. L. Campbell, Ullmann's Encyclopedia of Industrial Chemistry, Vol. 11 , Chapter "Cyclohexane”, pages 44 to 46, 2011 and the references cited therein.

[0130] In step d) of the process according to the present invention, the cyclohexane formed in step c) is oxidized in the presence of oxygen and, optionally, a second heterogeneous catalyst, whereby cyclohexanone is formed.

[0131] Cyclohexanone can be manufactured from cyclohexane for example by liquid-phase oxidation in the presence of air in an uncatalyzed or catalyzed reaction (e.g., cobalt catalyst as second heterogeneous catalyst) at a temperature in the range of about 140 °C to about 180 °C and a pressure in the range of 0.8 MPa to about 2 MPa. Cyclohexanone can also be manufactured from cyclohexane in the presence of anhydrous (meta-)boric acid. Cyclohexanol is produced by such processes as a side product. Such mixtures comprising cyclohexanone and cyclohexanol are also known as "KA oil” ("ketone-alcohol oil”) and "Anolon”. Suitable manufacturing processes for cyclohexanone from cyclohexane such as the above discussed ones are for example disclosed in M. T. Musser, Ullmann's Encyclopedia of Industrial Chemistry, Vol. 11 , Chapter "Cyclohexanol and Cyclohexanone”, pages 51 to 54, 2011 and the references cited therein.

[0132] The process according to the present invention optionally further comprises the steps e1) providing cyclohexanone of which at least a portion is manufactured by the process comprising steps a) to d), e2) converting cyclohexanone provided in step e1) to cyclohexanone oxime, e3) converting the cyclohexanone oxime formed in step e2) into azepan-2-one.

[0133] Azepan-2-one (caprolactam) is manufactured from cyclohexanone via cyclohexanone oxime as an intermediate. Next, cyclohexanone oxime is subjected to a Beckmann rearrangement by which azepan-2-one is formed.

[0134] Cyclohexanone oxime can be for example formed in optional step e1) from cyclohexanone in the presence of ammonium hydroxylammonium sulfate or by an ammoximation of cyclohexanone in the presence of ammonia and hydrogen peroxide.

[0135] Azepan-2-one can be formed from cyclohexanone oxime in optional step e3) by a Beckmann rearrangement. The Beckmann rearrangement reaction can be performed in the presence of a catalyst either in liquid phase or gas phase. For example, fuming sulfuric acid or oleum is used as a catalyst in liquid phase Beckmann rearrangement followed by a neutralization reaction and separation of the azepan-2-one which is then purified in further process steps.

[0136] Such manufacturing methods for azepan-2-one from cyclohexanone are for example disclosed in J. Tinge, M.

[0137] Groothaert, H. o. h. Veld, J. Ritz, H. Fuchs, H. Kieczka, W. C. Moran, Ullmann's Encyclopedia of Industrial Chemistry, Chapter "Caprolactam”, pages 4 to 16, 2018 and the references cited therein. In optional step e1), cyclohexanone formed in step d) of the process according to the present invention can be alone or mixed with cyclohexanone manufactured from benzene by other process steps than steps a1) to a6) converted into cyclohexanone oxime.

[0138] For example, a portion of the cyclohexanone which is converted in optional step e1) into cyclohexanone is manufactured by steps a) to d) of the process according to the present invention and another portion of the cyclohexanone which is converted in optional step e1) into cyclohexanone is for example manufactured from benzene of fossil origin and / or from benzene manufactured from renewable sources and / or from benzene manufactured from plastic waste by a process different than steps a) to d) of the process according to the present invention.

[0139] Preferably, at least 2.5 wt.-%, more preferably at least 5.0 wt.-% and most preferably at least 7.5 wt.% of the cyclohexanone provided in step e1) is cyclohexanone manufactured from a non-fossil feedstock.

[0140] Preferably, at least 2.5 wt.-%, more preferably at least 5.0 wt.-% and most preferably at least 7.5 wt.% of the cyclohexanone provided in step e1) is manufactured from benzene which is manufactured by steps a1) to an).

[0141] The process according to the present invention optionally further comprises the steps e4) providing azepan-2-one of which at least a portion was manufactured by steps a) to e3) wherein the benzene provided in step a) was manufactured by steps a1) to an), e5) converting at least a portion of azepan-2-one provided in step e4) into poly-(azepan-2-one).

[0142] Azepan-2-one can be for example converted in optional step e5) into poly-(azepan-2-one) by a hydrolytic polymerization of molten azepan-2-one in the presence of water. Such hydrolytic polymerization can be for example operated as a continuous process in so-called "VK tube” reactors. Methods for manufacturing poly-(azepan-2-one) from azepan- 2-one are for example described in B. Herzog, M. I. Kohan, S. A. Mestemacher, R. U. Pagilagan, K. Redmond, R. Sarbandi, Ullmann's Encyclopedia of Industrial Chemistry, Chapter "Polyamides”, pages 22 to 28, 2020 and the references cited therein.

[0143] A portion of azepan-2-one provided in step e4) can be manufactured by another method and from another feedstock than azepan-2-one manufactured by steps a) to e3) wherein the benzene provided in step a) was manufactured by steps a1) to a6). For example, said portion of azepan-2-one can be manufactured from benzene of fossil origin using the methods disclosed in J. Tinge, M. Groothaert, H. o. h. Veld, J. Ritz, H. Fuchs, H. Kieczka, W. C. Moran, Ullmann's Encyclopedia of Industrial Chemistry, Chapter "Caprolactam”, pages 4 to 16, 2018 and the references cited therein. Said portion of azepan-2-one can also be manufactured by a depolymerization process using plastic waste comprising poly-(azepan-2-one). Such methods are for example disclosed in WO 96 / 18612 A1 , EP 568882 A1 and EP 1975156 A1. Said portion may also comprises azepan-2-one from both foregoing sources. Preferably, at least 2.5 wt.-%, more preferably at least 5.0 wt.-% and most preferably at least 7.5 wt.% of the azepan- 2-one provided in step e4) is azepan-2-one manufactured from a non-fossil feedstock.

[0144] Preferably, at least 2.5 wt.-%, more preferably at least 5.0 wt.-% and most preferably at least 7.5 wt.% of the azepan- 2-one provided in step e4) is manufactured from benzene which is manufactured by steps a1) to a6).

[0145] The process according to the present invention optionally further comprises the steps f1) providing cyclohexanone of which at least a portion is manufactured by the process comprising steps a) to d), f2) converting at least a portion of the cyclohexanone provided in step f1) to hexanedioc acid.

[0146] Hexanedioic acid can be manufactured from cyclohexanone by oxidation in the presence of nitric acid, for example at temperature between about 60 °C to 80 °C and a pressure of about 0.1 MPa to about 0.4 MPa in the presence of a copper-vanadium catalyst. Optionally, a second reactor operating at a temperature from about 110 °c to about 120 °C is added to the process. Next, nitrogen oxides are removed with air and nitric acid is recovered from such mixtures. Hexanedioic acid can then be separated by crystallization and purified by recrystallization. Suitable manufacturing processes for hexanedioic acid cyclohexanone are for example described in M.T. Musser, Ullmann's Encyclopedia of Industrial Chemistry, Vol. 11, Chapter "Adipic Acid”, pages 2 to 5, 2005 and the references cited therein.

[0147] Preferably, at least 2.5 wt.-%, more preferably at least 5.0 wt.-% and most preferably at least 7.5 wt.% of the cyclohexanone provided in step f1) is cyclohexanone manufactured from a non-fossil feedstock.

[0148] Preferably, at least 2.5 wt.-%, more preferably at least 5.0 wt.-% and most preferably at least 7.5 wt.% of the cyclohexanone provided in step f1) is manufactured from benzene which is manufactured by steps a1) to a6).

[0149] Hexanedioic acid can then be used as a feedstock for manufacturing Poly[imino(1,6-dioxohexamethylene) iminohexamethylene).

[0150] The process according to the present invention optionally further comprises the steps f3) providing hexanedioc acid of which at least a portion was manufactured by steps f1) and f2), f4) providing hexane-1,6-diamine, f5) converting at least a portion of the hexanedioc acid provided in step f4) and the hexane-1,6-diamine provided in step f4) into poly[imino(1,6-dioxohexamethylene) iminohexamethylene).

[0151] The hexanedioic acid manufactured from mixtures comprising cyclohexanone can be used as a feedstock for the manufacture of poly[imino(1,6-dioxohexamethylene) iminohexamethylene). First, an aqueous solution comprising stochiometric amounts of hexanedioic acid and hexane-1,6-diamine is provided. This aqueous solution is optionally subjected to decolorization method using e.g., char coal prior to further use. Poly[imino(1,6-dioxohexamethylene) iminohexamethylene) can either prepared by batch processes or continuous processes from such aqueous solutions. Batch processes can be conducted in autoclaves at elevated temperatures. Continuous processes can be conducted by controlled evaporation in devices known as "separators” and "flashers” and in a final manufacturing step in "finisher” devices. Suitable methods for manufacturing poly[imino(1,6-dioxohexamethylene) iminohexamethylene) from hexanedioic acid and hexane-1,6-diamine are for example described in B. Herzog, M. I. Kohan, S. A. Mestemacher, R. U. Pagilagan, K. Redmond, R. Sarbandi, Ullmann's Encyclopedia of Industrial Chemistry, Chapter "Polyamides”, pages 19 to 21, 2020 and the references cited therein.

[0152] Preferably, at least 2.5 wt.-%, more preferably at least 5.0 wt.-% and most preferably at least 7.5 wt.% of the hex- anedioc acid provided in step f3) is hexanedioc acid manufactured from a non-fossil feedstock.

[0153] Preferably, at least 2.5 wt.-%, more preferably at least 5.0 wt.-% and most preferably at least 7.5 wt.% of the hexanedioc acid provided in step f3) is manufactured from benzene which is manufactured by steps a1) to a6).

[0154] The present invention is further illustrated by the following set of embodiments and combinations of embodiments resulting from the dependencies and back-references as indicated. In particular, it is noted that in each instance where a range of embodiments is mentioned, for example in the context of a term such as "The method of any of embodiments 1 to 3", every embodiment in this range is meant to be explicitly disclosed for the skilled person, i.e. the wording of this term is to be understood by the skilled person as being synonymous to "The method of any of embodiments 1, 2 and 3". Further, it is explicitly noted that the following set of embodiments represents a suitably structured part of the general description directed to preferred aspects of the present invention, and thus, suitably supports the present invention.

[0155] 1. Process for manufacturing cyclohexanone from benzene, the process comprising the steps a) providing benzene, b) providing hydrogen, c) contacting the benzene provided in step a) with the hydrogen provided in step b) in the presence of a first heterogeneous catalyst whereby cyclohexane is formed, d) oxidizing the cyclohexane formed in step c) in the presence of oxygen and, optionally, a second heterogeneous catalyst, whereby cyclohexanone is formed, characterized in that the at least a portion of the benzene provided in a) is manufactured by the steps a1) providing a liquid stream S1 comprising at least one pyrolysis oil, the liquid stream S1 further comprising C6-C8 aromatic hydrocarbons, organic compounds comprising at least one heteroatom and compounds having C-C double and / or C-C triple bonds, a2) providing a stream S2, the stream S2 comprising H2, a3) feeding the liquid stream S1 and the stream S2 into a hydrogenation unit HU1 in which at least a portion of the components of the liquid stream S1 reacts with stream S2 in a hydrogenation reaction whereby a liquid stream S3 is formed, wherein the liquid stream S3 is depleted in compounds having C-C double and / or C-C triple bonds in respect to liquid stream S1, and optionally feeding at least a portion of a liquid recycle steam S3', said liquid recycle stream S3' separated from the liquid stream S3, into said hydrogenation unit HU1, preferably wherein the mass ratio " liquid recycle steam S3' : liquid stream S3 ” preferably ranges between from about 1 :1 to about 30:1, more preferably from about 5:1 to about 20:1 and most preferably from about 10:1 to about 15:1, a4) subjecting at least a portion or the remaining portion of the liquid stream S3 to a distillation unit DU in which the at least portion or remaining portion of liquid stream S3 is separated into a value product containing stream S4 and a liquid stream S5, wherein the value product containing stream S4 comprises C6-C8 aromatic hydrocarbons and organic compounds comprising at least one heteroatom, a5) subjecting the value product containing stream S4 to a hydrogenation unit HU2 in which the stream S4 is converted into a stream S6, wherein the stream S6 comprises C6-C8 aromatic hydrocarbons and is depleted in organic compounds comprising at least one heteroatom and / or C-C double bonds in respect to stream S4, and a6) separating benzene from stream S6 in an aromatic hydrocarbon extraction unit AEU. Process according to embodiment 1 wherein preferably at least 2.5 wt.-%, more preferably at least 5.0 wt.-% and most preferably at least 7.5 wt.% of the benzene provided in step a) is benzene manufactured from a non-fossil feedstock. Process according to embodiment 1 or 2 wherein preferably at least 2.5 wt.-%, more preferably at least

[0156] 5.0 wt.-% and most preferably at least 7.5 wt.% of the benzene provided in step a) is manufactured by steps a1) to a6). Process according to any one of embodiments 1 to 3 wherein the at least one pyrolysis oil is manufactured by a pyrolysis of plastic waste. Process according to any one of embodiments 1 to 4 wherein the liquid stream S1 preferably comprises at least 15 wt.-% of C6-C8 aromatic hydrocarbons, more preferably at least 50 wt.-% of C6-C8 aromatic hydrocarbons and most preferably at least 80 wt.-% of C6-C8 aromatic hydrocarbons. Method according to any one of embodiments 1 to 5 wherein the at least one pyrolysis oil in the liquid stream

[0157] S1 has a bromine number of about 2 g Br2 / 100g to about 150 g Br2 / 100g (determined by ASTM 1159) and / or a C5 hydrocarbon content of about 0.03 wt.-% to about 12.2 wt.-% (determined by ASTM D 5134) and / or a naphthalene content of about 0.5 wt.-% to about 18.4 wt.-% (determined by ASTM D 5134) and / or a styrene content of about 0.02 wt.-% to about 29.5 wt.-% (determined by ASTM D 5134) and / or a toluene content of about 4.3 wt.-% to about 71.5 wt.-% (determined by ASTM D 5134).

[0158] 7. Process according to any one of embodiments 1 to 6 wherein the first hydroprocessing unit HU1 comprises at least one three-phase reactor, preferably at least one three-phase reactor with at least one fixed catalyst bed.

[0159] 8. Process according to any one of embodiments 1 to 7 wherein the first hydroprocessing unit HU1 comprises at least one heterogeneous catalyst, which at least one heterogeneous catalyst comprises at least one catalytically active metal selected from the element of groups 8 to 12 of the periodic table, more preferably the at least one catalytically active metal is selected from the group comprising or consisting of nickel, palladium, platinum, rhodium and most preferably the catalytically active metal is palladium.

[0160] 9. Process according to any one of embodiments 1 to 8 wherein the ratio "H2 in the fresh H2 feed stream S2 : chemical H2 consumption caused by the hydrogenation reaction(s) in the first hydroprocessing unit HUT' preferably ranges from about 1 : 1 to about 5: 1 , more preferably from about 1 : 1 to about 3: 1 and most preferably from about 1 : 1 to about 2:1.

[0161] 10. Process according to any one of embodiments 1 to 9 wherein the total pressure at the outlet the at least one reactor in the first hydroprocessing unit HU1 preferably ranges from about 5 bar (abs.) to about 60 bar (abs.), more preferably from about 10 bar (abs.) to about 40 bar (abs) and most preferably from about 20 bar (abs.) to about 40 bar (abs).

[0162] 1 1 . Process according to any one of embodiments 1 to 10 wherein the mass ratio "liquid recycle steam S3' : liquid stream S3” preferably ranges between from about 1 : 1 to about 30: 1 , more preferably from about 5: 1 to about 20: 1 and most preferred from about 10: 1 to about 15:1.

[0163] 12. Process according to any one of embodiments 1 to 11 wherein the wherein the second hydroprocessing unit HU2 comprises at least one fixed-bed reactor.

[0164] 13. Process according to any one of embodiments 1 to 12 wherein the first hydroprocessing unit HU1 comprises at least one heterogeneous catalyst, the at least one heterogeneous catalyst comprising at least one catalytically active metal which is selected from the group comprising or consisting of nickel, palladium, platinum, and rhodium.

[0165] 14. Process according to any one of embodiments 1 to 13 wherein the second hydroprocessing unit HU2 comprises at least one heterogeneous catalyst, the at least one heterogeneous catalyst selected from the group comprising or consisting of Co-Mo catalyst, Ni-Mo catalyst, Ni-W catalyst, Co-W catalyst, and Mo catalyst. 15. Process according to any one of embodiments 1 to 14 wherein C6-C8 aromatic hydrocarbons are separated from stream S6 by extractive distillation in at least one aromatic hydrocarbon extraction unit AEU.

[0166] 16. Process according to any one of embodiments 1 to 15 wherein the stream S5 is converted in at least one gasifier and / or partial oxidation reaction unit into syngas and / or wherein stream S8 is further subjected to a cracking process selected from catalytic cracking, thermal cracking, and steam cracking.

[0167] 17. Process according to any one of embodiments 1 to 16 wherein the process further comprises the steps e1) providing cyclohexanone of which at least a portion is manufactured by the process comprising steps a) to d), e2) converting cyclohexanone provided in step e1) to cyclohexanone oxime, e3) converting the cyclohexanone oxime formed in step e2) into azepan-2-one.

[0168] 18. Process according to embodiment 17 wherein preferably at least 2.5 wt.-%, more preferably at least 5.0 wt.-% and most preferably at least 7.5 wt.% of the cyclohexanone provided in step e1) is cyclohexanone manufactured from a non-fossil feedstock.

[0169] 19. Process according to embodiment 17 or 18 wherein preferably, at least 2.5 wt.-%, more preferably at least 5.0 wt.-% and most preferably at least 7.5 wt.% of the cyclohexanone provided in step e1) is manufactured from benzene which is manufactured by steps a1) to a6).

[0170] 20. Process according to any one of embodiments 17 to 19 wherein the process further comprises the steps e4) providing azepan-2-one of which at least a portion was manufactured by steps a) to e3) wherein at least a portion of the benzene provided in step a) was manufactured by steps a1) to a6), e5) converting at least a portion of azepan-2-one provided in step e4) into poly-(azepan-2-one).

[0171] 21. Process according to any one of embodiments 17 to 20 wherein preferably at least 2.5 wt.-%, more preferably at least 5.0 wt.-% and most preferably at least 7.5 wt.% of the azepan-2-one provided in step e4) is azepan-2- one manufactured from a non-fossil feedstock.

[0172] 22. Process according to any one of embodiments 17 to 21 wherein preferably at least 2.5 wt.-%, more preferably at least 5.0 wt.-% and most preferably at least 7.5 wt.% of the azepan-2-one provided in step e4) is manufactured from benzene which is manufactured by steps a1) to a6).

[0173] 23. Process according to any one of embodiments 1 to 16 wherein the process further comprises the steps f 1 ) providing cyclohexanone of which at least a portion is manufactured by the process comprising steps a) to d), f2) converting at least a portion of the cyclohexanone provided in step f1) to hexanedioc acid.

[0174] 24. Process according to embodiment 23 wherein preferably at least 2.5 wt.-%, more preferably at least 5.0 wt.-% and most preferably at least 7.5 wt.% of the cyclohexanone provided in step f1) is cyclohexanone manufactured from a non-fossil feedstock.

[0175] 25. Process according to embodiment 23 or 24 wherein preferably at least 2.5 wt.-%, more preferably at least 5.0 wt.-% and most preferably at least 7.5 wt.% of the cyclohexanone provided in step f1) is manufactured from benzene which is manufactured by steps a1) to a6).

[0176] 26. Process according to any of embodiments 23 to 25 wherein the process further comprises the steps f3) providing hexanedioc acid of which at least a portion was manufactured by steps f1) and f2), f4) providing hexane-1 ,6-diamine, f5) converting at least a portion of the hexanedioc acid provided in step f3) and the hexane-1 ,6-diamine provided in step f4) into poly[imino(1,6-dioxohexamethylene) iminohexamethylene).

[0177] 27. Process according to embodiment 26 wherein preferably at least 2.5 wt.-%, more preferably at least 5.0 wt.-% and most preferably at least 7.5 wt.% of the hexanedioc acid provided in step f3) is hexanedioc acid manufactured from a non-fossil feedstock.

[0178] 28. Process according to embodiment 25 or 26 wherein preferably at least 2.5 wt.-%, more preferably at least 5.0 wt.-% and most preferably at least 7.5 wt.% of the hexanedioc acid provided in step f3) is manufactured from benzene which is manufactured by steps a1) to a6).

[0179] 29. A chemical plant for manufacturing cyclohexanone from benzene from a liquid stream comprising at least one pyrolysis oil, the chemical plant comprising

[0180] (I) at least one first hydroprocessing unit HU1 , the at least one first hydroprocessing unit HU1

[0181] (II) comprising at least one inlet and at least one outlet,

[0182] (ill) optionally a recycle unit downstream of and fluidically connected to the inlet and the outlet of the first hydroprocessing unit HU1 ,

[0183] (iv) a distillation unit DU downstream of and fluidically connected to the outlet of the first hydroprocessing unit HU1, the distillation unit DU having a bottom outlet BO and a head outlet HO, wherein a heavies stream (stream S5) leaves the distillation unit DU through the bottom outlet BO and wherein a lights stream (stream S4) leaves the distillation unit DU through the head outlet HO,

[0184] (v) a second hydroprocessing unit HU2 downstream of and fluidically connected to the head outlet HO of the distillation unit DU, (vi) at least one aromatic hydrocarbon extraction unit AEU which is downstream and fluidically connected to the second hydroprocessing unit HU2.

[0185] 30. Use of a chemical plant according to embodiment 29 for the process according to any one of embodiments 1 to 28.

[0186] It is explicitly noted that the above set of embodiments represents a suitably structured part of the general description directed to preferred aspects of the present invention, and thus, suitably supports, but does not represent the claims of the present invention.

[0187] The invention will be further explained by the following non-limiting examples.

[0188] Examples

[0189] The invention will be further explained by the following non-limiting examples.

[0190] The process steps for separating benzene from a pyrolysis oil (comparative example and process steps a1) to a6) according to the present invention) were simulated using ASPEN Plus™ V11 simulation software in combination with a kinetic model to calculate the conversion in the first hydroprocessing unit HU1 and the second hydroprocessing unit HU2.

[0191] Comparative example

[0192] The comparative example is a method and a chemical plant for manufacturing benzene (stream S7') from a liquid stream S1 comprising a pyrolysis oil obtained by pyrolysis of plastic waste taught in AU 2021 / 222788 A1 and is schematically shown in Figure 1.

[0193] The process conditions used for the first hydroprocessing unit HU1 are summarized in Table 1 : chosen compositions for the streams S1 , S1 S3, S4, S6, S7', S7", S7'" and S8 are summarized in Table 2: am S1 ' = stream S1 + stream S2 + stream S3'.

[0194] The composition of the liquid stream S1 of the hydroprocessing unit HU1 is described in Tab. 2 with a dienic components concentration of 0.8 wt.-% and olefinic components concentration of 3.23 wt.%. The total content of C6-C8 aromatics is 73.13 wt.-%. The composition of the liquid stream S1 is identic to the liquid stream S1 used in the example according to the invention below. The liquid stream S1 is processed in the hydroprocessing unit HU 1 with conditions described in Tab. 1. The catalyst in the hydroprocessing unit HU1 is a Ni-Mo catalyst on an alumina support taught in AU 2021 / 222788 A1 . The pressure at the reactor outlet of the first hydroprocessing unit HU1 is 64 bar (abs.) and the reactor temperature rises from 119 °C (reactor inlet temperature) to 150 °C (reactor outlet temperature) by adiabatic temperature increase. Under these conditions typical trickle-bed flow of the liquid phase over the (solid) catalyst occurs which is desired.

[0195] The ratio "liquid feed S1 : liquid recycle stream S3'” from the hydroprocessing unit HU2 (Figure 1) is 1 : 1. Hence, the concentration of dienic components with 0.4 wt.-% is a factor of 5.7 higher than the concentration of dienic components in the example according to the present invention (see below) in the reactor inlet stream S1 '. The high temperature and much higher temperature increase of 31 °C (from the reactor inlet to reactor outlet of the first hydroprocessing unit HU1) in comparison to 5 °C in the example according to the present invention (see below) together with the much higher dienic components concentration causes a higher polymer formation during processing and so advances plugging which are both undesired.

[0196] The WHSV (weight hourly space velocity) of liquid stream S1 is 0.5 t / (m3Kat *h). The chemical hydrogen consumption in the hydroprocessing unit HU1 is 23 Nm3 / t. The molar ratio "stream comprising H2 S2 fed to the hydroprocessing unit HU1 : chemical hydrogen consumption” is 1.08 : 1. The small excess of hydrogen assures the sufficient activity of the catalyst to effect 99 % conversion of the dienic components and 68 % conversion of the olefinic components (stream S3). Under these operation conditions and the catalyst used (Ni-Mo catalyst on an alumina support), no hydrogenation of the aromatic components will occur. The reactor product of hydroprocessing unit HU1 (stream S3 in Fig. 1) is directly fed to the hydroprocessing unit HU2.

[0197] The process conditions in the second hydroprocessing unit HU2 are summarized in Table 3:

[0198] Table 3 shows the process conditions of the hydroprocessing unit HU2. The pressure at reactor outlet is 63 bar (abs.). The ratio "HU2 internal recycle-gas S4" : feed stream S3” is 392 Nm3 / t and the reactor inlet temperature of the second hydroprocessing unit HU2 is 342 °C. Under these conditions, the feed stream S3 of the hydroprocessing unit HU2 is completely evaporated. Caused by the low content of dienic components of < 0.01 wt.-% in the feed stream S3 of the hydroprocessing unit HU2 no undesired polymerization and fouling occurs during total evaporation. The reactor temperature rises from an inlet temperature of 342 °C to an outlet temperature of 355 °C by the exotherm hydrogenation reactions mentioned above. The temperature rise is 13 °C because 69 % of the olefins are already hydrogenated in the hydroprocessing unit HU1.

[0199] To limit the undesired hydrogenation of the aromatic rings, such a low exothermic temperature increase of 13 °C is beneficial. The hydrogen partial pressure in the reactor of 39 bar (abs.) is sufficient to assure a sufficient hydrogenation activity but avoid undesired aromatic ring hydrogenation. The catalyst in the hydroprocessing unit HU2 is a standard Co-Mo catalyst on an alumina support which shows sufficient dienic- and olefinic-hydrogenation, desulfurization, denitration and dehalogenation activity and very low aromatic ring hydrogenation activity but needs higher temperatures than the Co-Mo catalyst on an alumina support in the example according to the present invention below. The loss of aromatic components by aromatic ring hydrogenation is < 0.5 %. The WHSV of the feed stream S3 is 0.7 t / (m3Kat*h).

[0200] The cooled down condensed liquid reaction product S4 leaving the second hydroprocessing unit HU2 is fed with a ratio of 1 : 1 together with the liquid feed stream S1 back to the hydroprocessing unit HU1 to dilute the liquid feed stream S1 bevor entering the first hydroprocessing unit HU1 . The necessity and effect of the dilution is described above for the hydroprocessing unit HU1.

[0201] Next step is the distillation in the distillation unit DU to remove the unwanted high boiling components in front of the aromatic hydrocarbon extraction unit AEU. High boiling components are undesired in the aromatic hydrocarbon extraction unit AEU because they accumulate in the solvent of the aromatic extraction unit AEU and contaminate the solvent. Hence the efficiency of the aromatic hydrocarbon extraction in the aromatic hydrocarbon extraction unit AEU would be affected.

[0202] The results of the distillation in the distillation unit DU are shown in Table 4.

[0203] In the distillation unit DU, the light boiling fraction with most of the C6-C8 aromatic components goes overhead.

[0204] These are 78 wt.-% of the stream S4 to the distillation unit DU. The content of C6-C8 aromatic components is thereby raised from 69.5 wt.-% to 83.0 wt.-%. The high boiling components are separated by the bottoms stream S5. The valued product overhead stream S4 is 78 % of the distillation unit DU feed stream S3 and comprises 93 wt.-% of the C6-C8 aromatic components. The stream S6 from the head section of the distillation unit DU is then fed into the aromatic hydrocarbon extraction unit AEU. Here pure benzene (>99 wt.-%), pure toluene (>99 wt.-%) and a xylene / ethylbenzene mixture (>93 wt.-%) are separated by an extractive distillation process. The remaining stream S8 is depleted in C6-C8 aromatics components and comprises the paraffinic components, naphthenic components and the C8+ aromatic hydrocarbons.

[0205] Example (inventive)

[0206] The process steps a1) to a6) according to the present invention were simulated in this example following the schematic representation in Figure 3 (stream S7' is suited to provide benzene in process step a)). Tab.5 process conditions in the first hydroprocessing unit HU1 :

[0207] he chosen compositions for the streams S1 , S1 S3, S4, S6, S7', S7", S7'" and S8 are summarized in Table 6: tream S1 ' = stream S1 + stream S2 + stream S3'.

[0208] The composition of the liquid stream S1 fed into the first hydroprocessing unit HU 1 is described in Tab.6 with a dienic components concentration of 0.8 wt.-% and olefinic components concentration of 3.23 wt.%. The total content of C6-C8 aromatics is 73.13 wt.-%. The liquid stream S1 is processed in the first hydroprocessing unit HU1 with conditions described in Tab.5. The catalyst in the first hydroprocessing unit HU 1 is a catalyst comprising palladium on an alumina support which allows very mild reaction conditions (e.g., a lower temperature). The pressure at the reactor outlet is 30 bar (abs.) in the first hydroprocessing unit HU1 and the reactor temperature rises from 80 °C reactor inlet temperature to 85 °C reactor outlet temperature by adiabatic temperature increase. Under these conditions typical trickle bed flow of the liquid phase over the catalyst occurs. The ratio "liquid feed S1 : liquid recycle stream S3' ” causes a very low dienic components concentration of 0.07 wt.-% and olefinic components content of 0.97 wt.% in the reactor inlet stream S1 '. The low temperature and mild temperature of only 6 °C increase, the high pressure together with the low dienic components concentration assures the avoidance of undesired polymer formation and fouling during processing.

[0209] The WHSV (weight hourly space velocity) of the liquid stream S1 is 0.5 t / (m3Kat*h). The chemical hydrogen consumption in the first hydroprocessing unit HU1 is 28 Nm3 / t. The molar ratio "stream S2 comprising hydrogen fed to the first hydroprocessing unit HU1 : chemical hydrogen consumption” is 1.2 : 1. The small excess of hydrogen assures the sufficient activity of the catalyst to effect 99 % conversion of the dienic components and 76 % conversion of the olefinic components (stream S3). Under this operation conditions no hydrogenation of the aromatic components will occur. The stream S3 leaving the first hydrogenation unit HU1 is stable enough and no undesired fouling by polymerization occurs in the distillation unit DU.

[0210] The results of the distillation in the distillation unit DU are shown in Table 7:

[0211] For the liquid stream S1 it is necessary to separate the high boilers from stream S3 to assure a complete evaporation of the stream S3 in the second hydroprocessing unit HU2.

[0212] In the distillation unit DU, the light boiling fraction with most of the C6-C8 aromatic hydrocarbons go overhead.

[0213] These are 78 wt.-% of the total feed to the distillation unit DU stream S4. The content of C6-C8 aromatic hydrocarbons is raised from 69.0 wt.-% to 82.5 wt.%. The high boiling components are separated by the bottoms stream S5. The valued product overhead stream S4 is 78 wt.-% of the distillation unit DU feed stream S3 and comprises 93 wt.- % of the C6-C8 aromatic hydrocarbons.

[0214] The valued product overhead stream S4 of the distillation unit DU is further processed in the second hydroprocessing unit HU2. Here the remaining small amounts of dienic and olefinic components are hydrogenated in the gas-phase to the corresponding saturated hydrocarbons. The sulfur containing components are hydrogenated to the correspond- ing saturated hydrocarbons and H2S. The sulfur content in the hydroprocessed product stream S6 is < 0.5 wt.-ppm. The nitrogen containing components are hydrogenated to the corresponding saturated hydrocarbons and NH3. The nitrogen content in the hydroprocessed product stream S6 is < 10 wt.-ppm The halogen-, like chlorine-containing components are hydrogenated to the corresponding saturated hydrocarbons and hydrohalogenic acids such as HCI The halogens / chlorine content in the hydroprocessed product stream S6 is < 1 wt.-ppm.

[0215] The process conditions for the second hydroprocessing unit HU2 are shown in Tab. 8:

[0216] Table 8 shows the process conditions of the second hydroprocessing unit HU2. The pressure at reactor outlet is 51 bar(abs.). The ratio "recycle-gas stream S6" : feed stream S4” is 577 Nm3 / t and the reactor inlet temperature is 267 °C. Under these conditions, the inlet stream S4 of the second hydroprocessing unit HU2 is totally evaporated. Caused by the low content of dienic components of < 0.01 wt.-% in the feed stream S4, no undesired polymerization and fouling occurs during inside the second hydroprocessing unit HU2. The reactor temperature rises from 267 °C inlet temperature to 281 °C outlet temperature by the exotherm hydrogenation reactions inside the second hy- drporcessing unit HU2 mentioned above. The temperature rise is limited to favorable low 14 °C because 76 % of the olefins are already hydrogenated in the first hydroprocessing unit HU1 . Such a low exothermic temperature increase inside the second hydroprocessing unit HU2 is beneficial to limit the undesired hydrogenation of the C6-C8 aromatic hydrocarbons. The hydrogen partial pressure in the reactor of the second hydroprocessing unit HU2 of 36 bar is suited to assure a sufficient hydrogenation activity but to avoid the undesired hydrogenation of the C6-C8 aromatic hydrocarbons.

[0217] The catalyst in the second hydroprocessing unit HU2 is a Co-Mo catalyst on an alumina support which shows sufficient dienic- and olefinic-hydrogenation, desulfurization, denitration and dehalogenation activity and the desired very low C6-C8 aromatic hydrocarbons hydrogenation activity. The loss of aromatic components by aromatic ring hydrogenation is < 0.5 %. The WHSV of the stream S4 is 0.7 t / (m3Kat *h).

[0218] The stream S6 leaving the second hydroprocessing unit HU2 is the fed to the aromatic hydrocarbon extraction unit AEU which yields pure benzene (>99 wt.-%), pure toluene (>99 wt.-%) and a xylene / ethylbenzene mixture (>93 wt.- %) which are separated in the aromatic hydrocarbon extraction unit AEU by an extractive distillation process. The remaining stream S8 is depleted in C6-C8 aromatic hydrocarbons and comprises the paraffinic components, naphthenic components and the C8+ aromatic hydrocarbons. Stream S7' is then suited to provide benzene in step a) of the process according to the present invention.

Claims

Claims1. Process for manufacturing cyclohexanone from benzene, the process comprising the steps a) providing benzene, b) providing hydrogen, c) contacting the benzene provided in step a) with the hydrogen provided in step b) in the presence of a first heterogeneous catalyst whereby cyclohexane is formed, d) oxidizing the cyclohexane formed in step c) in the presence of oxygen and, optionally, a second heterogeneous catalyst, whereby cyclohexanone is formed, characterized in that the at least a portion of the benzene provided in a) is manufactured by the steps a1) providing a liquid stream S1 comprising at least one pyrolysis oil, the liquid stream S1 further comprising C6-C8 aromatic hydrocarbons, organic compounds comprising at least one heteroatom and compounds having C-C double and / or C-C triple bonds, a2) providing a stream S2, the stream S2 comprising H2, a3) feeding the liquid stream S1 and the stream S2 into a hydrogenation unit HU1 in which at least a portion of the components of the liquid stream S1 reacts with stream S2 in a hydrogenation reaction whereby a liquid stream S3 is formed, wherein the liquid stream S3 is depleted in compounds having C-C double and / or C-C triple bonds in respect to liquid stream S1, and optionally feeding at least a portion of a liquid recycle steam S3', said liquid recycle stream S3' separated from the liquid stream S3, into said hydrogenation unit HU1, preferably wherein the mass ratio " liquid recycle steam S3' : liquid stream S3 ” preferably ranges between from about 1 :1 to about 30:1, more preferably from about 5:1 to about 20:1 and most preferably from about 10:1 to about 15:1, a4) subjecting at least a portion or the remaining portion of the liquid stream S3 to a distillation unit DU in which the at least portion or remaining portion of liquid stream S3 is separated into a value product containing stream S4 and a liquid stream S5, wherein the value product containing stream S4 comprises C6-C8 aromatic hydrocarbons and organic compounds comprising at least one heteroatom, a5) subjecting the value product containing stream S4 to a hydrogenation unit HU2 in which the stream S4 is converted into a stream S6, wherein the stream S6 comprises C6-C8 aromatic hydrocarbons and is depleted in organic compounds comprising at least one heteroatom and / or C-C double bonds in respect to stream S4, and a6) separating benzene from stream S6 in an aromatic hydrocarbon extraction unit AEU.

2. Process according to claim 1 wherein preferably at least 2.5 wt.-%, more preferably at least 5.0 wt.-% and most preferably at least 7.5 wt.% of the benzene provided in step a) is benzene manufactured from a nonfossil feedstock.

3. Process according to claim 1 or 2 wherein preferably at least 2.5 wt.-%, more preferably at least 5.0 wt.-% and most preferably at least 7.5 wt.% of the benzene provided in step a) is manufactured by steps a1) to a6).

4. Process according to any one of claims 1 to 3 wherein the at least one pyrolysis oil is manufactured by a pyrolysis of plastic waste.

5. Process according to any one of claims 1 to 4 wherein the at least one pyrolysis oil in the liquid stream S1 has a bromine number of about 2 g Br2 / 100g to about 150 g Br2 / 100g (determined by ASTM 1159) and / or a C5 hydrocarbon content of about 0.03 wt.-% to about 12.2 wt.-% (determined by ASTM D 5134) and / or a naphthalene content of about 0.5 wt.-% to about 18.4 wt.-% (determined by ASTM D 5134) and / or a styrene content of about 0.02 wt.-% to about 29.5 wt.-% (determined by ASTM D 5134) and / or a toluene content of about 4.3 wt.-% to about 71 .5 wt.-% (determined by ASTM D 5134).

6. Process according to any one of claims 1 to 5 wherein the process further comprises the steps e1) providing cyclohexanone of which at least a portion is manufactured by the process comprising steps a) to d), e2) converting cyclohexanone provided in step e1) to cyclohexanone oxime, e3) converting the cyclohexanone oxime formed in step e2) into azepan-2-one.

7. Process according to claim 6 wherein preferably, at least 2.5 wt.-%, more preferably at least 5.0 wt.-% and most preferably at least 7.5 wt.% of the cyclohexanone provided in step e1) is manufactured from benzene which is manufactured by steps a1) to a6).

8. Process according to claim 6 or 7 wherein the process further comprises the steps e4) providing azepan-2-one of which at least a portion was manufactured by steps a) to e3) wherein at least a portion of the benzene provided in step a) was manufactured by steps a1) to a6), e5) converting at least a portion of azepan-2-one provided in step e4) into poly-(azepan-2-one).

9. Process according to claim 8 wherein preferably at least 2.5 wt.-%, more preferably at least 5.0 wt.-% and most preferably at least 7.5 wt.% of the azepan-2-one provided in step e4) is manufactured from benzene which is manufactured by steps a1) to a6).

10. Process according to any one of claims 1 to 5 wherein the process further comprises the steps f1) providing cyclohexanone of which at least a portion is manufactured by the process comprising steps a) to d), f2) converting at least a portion of the cyclohexanone provided in step f1) to hexanedioc acid.11 . Process according to claim 10 wherein preferably at least 2.5 wt.-%, more preferably at least 5.0 wt.-% and most preferably at least 7.5 wt.% of the cyclohexanone provided in step f1) is manufactured from benzene which is manufactured by steps a1) to a6).

12. Process according to claim 9 or 10 wherein the process further comprises the steps f3) providing hexanedioc acid of which at least a portion was manufactured by steps f1) and f2), f4) providing hexane-1,6-diamine, f5) converting at least a portion of the hexanedioc acid provided in step f3) and the hexane-1,6-diamine provided in step f4) into poly[imino(1,6-dioxohexamethylene) iminohexamethylene).

13. Process according to claim 12 wherein preferably at least 2.5 wt.-%, more preferably at least 5.0 wt.-% and most preferably at least 7.5 wt.% of the hexanedioc acid provided in step f3) is manufactured from benzene which is manufactured by steps a1) to a6).

14. A chemical plant for manufacturing cyclohexanone from benzene from a liquid stream comprising at least one pyrolysis oil, the chemical plant comprising(I) at least one first hydroprocessing unit HU1, the at least one first hydroprocessing unit HU1(II) comprising at least one inlet and at least one outlet,(ill) optionally a recycle unit downstream of and fluidically connected to the inlet and the outlet of the first hydroprocessing unit HU1,(iv) a distillation unit DU downstream of and fluidically connected to the outlet of the first hydroprocessing unit HU1, the distillation unit DU having a bottom outlet BO and a head outlet HO, wherein a heavies stream (stream S5) leaves the distillation unit DU through the bottom outlet BO and wherein a lights stream (stream S4) leaves the distillation unit DU through the head outlet HO,(v) a second hydroprocessing unit HU2 downstream of and fluidically connected to the head outlet HO of the distillation unit DU,(vi) at least one aromatic hydrocarbon extraction unit AEU which is downstream and fluidically connected to the second hydroprocessing unit HU2.

15. Use of a chemical plant according to claim 14 for the process according to any one of claims 1 to 13.

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