Process for manufacturing aniline and (DI)amino derivatives of 1-methylbenzene from plastic waste and chemical products based on cyclohexanone manufactured from plastic waste
The process of converting plastic waste into aniline and (di)amino derivatives of 1-methylbenzene through pyrolysis and hydrogenation addresses the challenge of recycling these critical chemical intermediates, achieving a 100% recycle content and supporting sustainable production of polyurethane derivatives.
Patent Information
- Application Number
- PCT/EP2024/083745
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- Priority Date
- 2023-12-07
- Filing Date
- 2024-11-27
- Publication Date
- 2025-06-12
AI Technical Summary
The chemical industry faces challenges in recycling aniline and (di)amino derivatives of 1-methylbenzene, which are crucial intermediates for producing polyurethanes and other chemicals, due to the reliance on fossil-based sources and the need for closed-loop recycling of aromatic core molecules.
A process is developed to manufacture aniline and (di)amino derivatives of 1-methylbenzene from plastic waste, involving steps such as pyrolysis of plastic waste to produce pyrolysis oil, hydrogenation of this oil to deplete unsaturated compounds, and subsequent separation and extraction to obtain benzene and 1-methylbenzene, which are then nitro-genated and hydrogenated to produce the desired amino compounds.
This process achieves a 100% recycle content for aniline and (di)amino derivatives of 1-methylbenzene when using plastic waste as feedstock, enabling the production of di- and poly-isocyanate derivatives and subsequent polyurethane products with high recycle content, thus addressing the need for sustainable recycling in the chemical industry.
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Abstract
Description
[0001] Process for manufacturing aniline and (di)amino derivatives of 1 -methyl benzene 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 aniline and (di)amino derivatives of 1 -methylbenzene and chemical products based on aniline and (di)amino derivatives of 1 -methylbenzene from plastic waste.
[0004] Background of the invention
[0005] Aniline and (di)amino derivatives of 1 -methylbenzene are important intermediate products in the chemical industry from which di- or poly-isocyanate derivatives of benzene and 1-methylbenzene are manufactured. Such isocyanate derivatives of benzene and 1-methylbenzene are then used as building blocks in the manufacture of polyurethanes and thermoplastic polyurethanes (abbreviated PUs and TPUs, respectively, and (T)PUs when referring to both types of polyurethanes), polyisocyanurates (PIR) and polyureas.
[0006] The usual starting materials for the manufacture of aniline is benzene and for (di)amino derivatives of 1- methylbenzene 1-methylbenzene, which are both isolated from fossil sources such as processed crude oil.
[0007] Aniline and (di)amino derivatives of 1-methylbenzene are then manufactured from benzene and 1-methylbenzene by a nitrogenating reaction followed by a hydrogenation reaction if the respective nitrogenated intermediates.
[0008] Future regulations and customers might require a certain percentage of recycled content in aniline, (di)amino derivatives of 1-methylbenzene and chemical products manufactured therefrom. Hence, there is a need for recycling options and recycling feedstock for polymers such as PU that is based on mixed plastic waste (e.g., some PU applications go into very small scale or dispersed applications, such as adhesives and coatings which cannot be collected on a large scale and then recycled in a closed loop).
[0009] The main carbon atom contributor to building blocks of (T)PUs, polyisocyanurates (PIR) and polyureas is the aromatic core molecule, i.e., aniline and / or (di)amino derivatives of 1-methylbenzene and their respective isocyanate derivatives. Accordingly, the aromatic core molecule is also the most important building block that needs to be recycled.
[0010] 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.
[0011] A process for separating C6-C8 aromatic hydrocarbons from plastic pyrolysis oils is disclosed in US10513661 B2. 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.
[0012] It is a first objective of the present invention to provide a process for manufacturing aniline and (di)amino derivatives of 1 -methylbenzene from plastic waste.
[0013] It is a second objective if the present invention to provide a process for manufacturing of di- and poly-isocyanate derivatives of benzene and 1 -methylbenzene such as 1-isocyanato-benzene, 1,1 '-methylenebis(4- isocyanatobenzene) and 2,4-diisocyanato-1-methylbenzene from plastic waste.
[0014] It is a third objective of the present invention to provide di- and poly-isocyanate derivatives of benzene, such as 1,1 '- methylenebis(4-isocyanatobenzene), and 1 -methylbenzene, such as 2,4-diisocyanato-1-methylbenzene, manufactured from plastic waste for manufacture of (T)PUs, polyisocyanurates and polyureas.
[0015] Summary of the Invention
[0016] These problems are solved by a process for manufacturing aromatic amino compounds from benzene and 1- methylbenzene comprising the steps a) providing benzene or 1 -methylbenzene and a mixture of nitric acid and sulfuric acid, b) contacting benzene or 1 -methylbenzene with the mixture of nitric acid and sulfuric acid whereby nitrobenzene or a nitro-derivative of 1 -methylbenzene is formed, d) hydrogenate the nitrobenzene or nitro-derivative of 1 -methylbenzene formed in step b) in the presence of hydrogen and, optionally, a catalyst, whereby aniline or an amino-derivative of 1 -methylbenzene is formed, characterized in that at least a portion of the benzene or 1 -methylbenzene provided in step a) is manufactured by a1) providing a liquid stream S1 comprising at least one pyrolysis oil, the liquid stream S1 further comprising
[0017] 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 a portion or the 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 and / or 1 -methylbenzene from stream S6 in an aromatic hydrocarbon extraction unit AEU.
[0018] These problems are further solved by a chemical plant for manufacturing aromatic amino compounds from benzene and 1-methylbenzene 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 comprising at least one inlet and at least one outlet,
[0019] (ii) optionally a recycle unit downstream of and fluidically connected to the inlet and the outlet of the first hydroprocessing unit HU1,
[0020] (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,
[0021] (iv) a second hydroprocessing unit HU2 downstream of and fluidically connected to the head outlet HO of the distillation unit DU,
[0022] (v) at least one aromatic hydrocarbon extraction unit AEU which is downstream and fluidically connected to the second hydroprocessing unit HU2.
[0023] Said chemical plant is suited for steps a1) to a6) and providing benzene and / or 1-methylbenzen in step a) of the process according to the present invention.
[0024] The process according to the present invention provides the following advantages:
[0025] First, aniline or an amino-derivative of 1-methylbenzene can be manufactured from plastic waste as feedstock and has therefore a recycle-content of 100 % in case all benzene or 1-methylbenzene provided in step a) is manufactured by steps a1) to a6).
[0026] Aniline or an amino-derivative of 1-methylbenzene is formed 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 or 1-methylbenzene 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 aniline or an amino-derivative of 1- methylbenzene with a desired recycle-content of less than 100 %. Second, the aniline or an amino-derivative of 1 -methylbenzene manufactured from plastic waste and therefore having a recycle-content can be used as the feedstock for manufacturing di- or poly-isocyanate derivatives of benzene and 1-methylbenzene, such as 1,1 '-methylenebis(4-isocyanatobenzene) (“MDI”) and 2,4-diisocyanato-1- methylbenzene (“TDI”) which, accordingly, also have a recycle-content of up to 100 % in case all aniline or an aminoderivative of 1-methylbenzene is manufactured from benzene or 1-methylbenzene provided in step a) is manufactured by steps a1) to a6). Di- or poly-isocyanate derivatives of benzene and 1-methylbenzene having a recyclecontent of less than 100 % can be manufactured from aniline or an amino-derivative of 1-methylbenzene having a recycle-content of less than 100 %. Accordingly, the process according to the present invention also enables manufacture of di- or poly-isocyanate derivatives of benzene and 1-methylbenzene with a desired recycle-content of less than 100 %.
[0027] Third, the di- or poly-isocyanate derivatives of benzene and 1-methylbenzene manufactured from plastic waste and therefore having a recycle-content can be used as the feedstock for manufacturing (T)PUs, polyisocyanurates and polyurea which, accordingly, have also a recycle-content of up to 100 % in case all di- or poly-isocyanate derivatives of benzene and 1-methylbenzene is manufactured from benzene or 1-methylbenzene provided in step a) is manufactured by steps a1) to a6) and further building blocks for the respective polymerization reaction are have a recycle content of 100 %. (T)PUs, polyisocyanurates and polyurea having a recycle-content of less than 100 % can be manufactured from di- or poly-isocyanate derivatives of benzene and 1-methylbenzene having a recycle-content of less than 100 %. Accordingly, the process according to the present invention also enables manufacture of (T)PUs, polyisocyanurates and polyurea with a desired recycle-content of less than 100 %.
[0028] Fourth, in case the plastic waste from which (T)PUs, polyisocyanurates and polyurea having a recycle-content is produced comprises (T)PUs, polyisocyanurates and / or polyurea, the process according to the present invention is a closed recycling loop for (T)PUs, polyisocyanurates and / or polyurea.
[0029] Fifth, in manufacture of benzene or 1-methylbenzene manufactured from plastic waste according to steps a1) to a6) undesired polymerization and fouling is suppressed (see Examples).
[0030] 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.
[0031] Figure 2 shows the process for manufacturing benzene and 1-methylbenzene according to steps a1) to a6) from plastic waste according to the first embodiment of the present invention.
[0032] Figure 3 shows the process for manufacturing benzene and 1-methylbenzene according to steps a1) to a6) from plastic waste according to the second embodiment of the present invention. Detailed description of the invention
[0033] 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.
[0034] Definitions:
[0035] 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. “Poly-isocyanate” is defined herein as molecules comprising more than two isocyanate residues.
[0036] In step a) of the process according to the present invention, benzene or 1-methylbenzene is provided. At least a portion of the benzene or 1-methylbenzene provided in step a) is manufactured by steps a1) to a6). Benzene and 1- methylbenzene manufactured by steps a1) to a6) have a recycle-content of 100 %.
[0037] 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.
[0038] 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). 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.
[0039] 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.
[0040] Accordingly, the term "plastic waste” includes industrial and domestic plastic waste and including used tires and agricultural and horticultural plastic material.
[0041] 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.
[0042] 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.
[0043] 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). 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.
[0044] 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.
[0045] 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.
[0046] 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.
[0047] 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. 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).
[0048] 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.
[0049] 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.
[0050] 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.
[0051] 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.
[0052] 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.
[0053] 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.
[0054] 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.
[0055] 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.
[0056] 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.
[0057] 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.
[0058] 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.
[0059] 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.
[0060] 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.
[0061] 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.
[0062] 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 .
[0063] 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).
[0064] 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. 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'.
[0065] 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.
[0066] 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 .
[0067] 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.
[0068] 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.
[0069] 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.
[0070] 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.
[0071] 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. 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.
[0072] 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.
[0073] 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.
[0074] 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.
[0075] 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.
[0076] The hydrogenation reaction is an exothermic reaction and therefore each reaction stage may optionally be cooled.
[0077] 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.
[0078] 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 reac- tor 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.
[0079] 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.
[0080] To maintain a high H2 partial pressure in the first hydroprocessing unit HU1, 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.
[0081] 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).
[0082] 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 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 (ill). 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.
[0083] 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.
[0084] 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. 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.
[0085] 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 # 1.013 bar.
[0086] 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.
[0087] 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'.
[0088] 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 NH4Hal (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.
[0089] 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).
[0090] 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.
[0091] The second hydroprocessing unit HU2 is downstream of and fluidically connected to the distillation unit DU.
[0092] 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.
[0093] 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.
[0094] 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.
[0095] 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 purpose 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.
[0096] 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.
[0097] 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.
[0098] 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.
[0099] 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.
[0100] The hydrogenation reaction is an exothermic reaction and therefore each reaction stage may optionally be cooled.
[0101] 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.
[0102] 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.
[0103] 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. 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).
[0104] 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.
[0105] 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.
[0106] 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.
[0107] More preferably, the stream S6, or a portion thereof is not recycled (inserted again) into the first hydroprocessing unit HU1.
[0108] 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.
[0109] 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. 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.
[0110] 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.
[0111] 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.
[0112] 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.
[0113] The stream S7" preferably comprises at least 90 wt.-% 1 -methylbenzene, more preferably at least 95 wt.-% 1- methylbenzene and most preferably at least 99-wt.-% methylbenzene. Stream S7" is suited for providing the 1- methylbenzene in step a) of the process according to the present invention.
[0114] 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.
[0115] The individual units of the chemical plant for manufacturing aromatic amino compounds from benzene and 1- methylbenzene from a liquid stream comprising at least one pyrolysis oil and their connectivity are shown in Figure 2 and will be described below:
[0116] The chemical plant for manufacturing aromatic amino compounds from benzene and 1 -methylbenzene from a liquid stream comprising at least one pyrolysis oil 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.
[0117] 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.
[0118] The stream S3 is separated in the distillation unit DU into a stream S4 ("lights stream”) and a stream S5 ("heavies stream”).
[0119] 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.
[0120] 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'.
[0121] 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.
[0122] 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. Preferably, at least 2.5 wt.-%, more preferably at least 5.0 wt.-% and most preferably at least 7.5 wt.% of the benzene or 1 -methylbenzene provided in step a) is benzene or 1 -methylbenzene manufactured from a non-fossil feedstock.
[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 or 1 -methylbenzene provided in step a) is manufactured by steps a1) to a6).
[0124] Benzene and 1 -methylbenzene can be for example separated from fossil feedstocks such as pyrolysis gasoline and coke-oven light oil which is described above.
[0125] Preferably, the plastic waste used to manufacture the at least one pyrolysis oil provided in step a1) comprises at least one type of polymers selected from the group consisting of thermoplastic polyurethanes, polyurethanes, poly i- socyanurates and polyureas. Thereby, a closed recycling-loop is achieved by the process according to the present invention.
[0126] In step a) also a mixture of nitric acid and sulfuric acid is provided.
[0127] In step b) of the process according to the present invention, benzene or 1-methylbenzene is contacted with the mixture of nitric acid and sulfuric acid whereby nitrobenzene or a nitro-derivative of 1-methylbenzene is formed, wherein the nitro-derivative of 1-methylbenzene is preferably selected from the group consisting of 2-nitro-1 -methylbenzene, 3-nitro1 -methylbenzene, 4-nitro1 -methylbenzene, 2, 4-dinitro1 -methylbenzene, 2, 6-dinitro1 -methylbenzene and mixtures thereof.
[0128] Benzene or 1-methylbenzene are converted to nitrobenzene or (di)nitro derivatives of 1-methylbenzene by direct nitration in liquid phase using a mixture of nitric acid and sulfuric acid ("nitrating acid”). The nitration reaction can be made by an isothermal reaction at a temperature of about 50 °C to about 100 °C and ambient pressure in a cascade of reactors (stirred cylindrical or tubular) or by an adiabatic reaction in a cascade of stirred reactors or a jet impingement reactor at a temperature in the range of about 90 °C to about 190 °C and ambient pressure or increased pressure such as 1.5 bar, 2 bar or even higher pressure such as 5 bar or 10 bar.
[0129] In step d) of the process according to the present invention, the nitrobenzene or nitro-derivative of 1-methylbenzene formed in step b), preferably the mono-nitro-derivatives of the aforementioned, is hydrogenated in the presence of hydrogen and, optionally, a catalyst, whereby aniline or an amino-derivative of 1-methylbenzene is formed, wherein the amino-derivative of 1-methylbenzene is preferably selected from the group consisting of 2-amino-1- methylbenzene, 3-amino-1 -methylbenzene, 4-amino-1 -methylbenzene, 2, 4-amino-1 -methylbenzene, 2,6-amino-1- methylbenzene and mixtures thereof. Aniline is manufactured from benzene via nitrobenzene, (di)amino-derivatives of 1 -methylebenzene are manufactured via (di)nitro-l-methylbenzene derivatives manufactured from 1 -methylbenzene.
[0130] Hydrogen used in step d) can be in principle hydrogen generated from any known source and by any known method.
[0131] Preferably, hydrogen used in step d) is preferably "blue hydrogen” (formed by steam reforming and / or autothermal reforming of natural gas whereby the CO2 formed during said reactions is captured and stored or otherwise used), more 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 formed by a methane pyrolysis, preferably a methane pyrolysis using at least partially methane from a renewable source. Methane from a renewable source comprises biomethane. Hydrogen can also be provided as a side product of pyrolysis of plastic waste such as mixed plastic waste and / or end-of-life tires.
[0132] Nitrobenzene or the (di)nitro derivative of 1 -methylbenzene is catalytically hydrogenated to aniline or to a (di)amino derivative of 1 -methylbenzene in vapor phase or liquid phase.
[0133] Fixed-bed or fluidized-bed reactors can be used for the gas-phase hydrogenation of nitrobenzene to aniline and of (di)nitro derivatives of 1 -methylbenzene to (di)amino derivatives of 1 -methylbenzene in the presence of at least one catalyst. The at least one catalyst is preferably a copper and / or palladium catalyst on a support (e.g., activated carbon or oxide(s) such as alumina or silica) and optionally further comprises elements such as lead, vanadium, phosphorous, chromium as modifiers or promoters. One particular gas-phase process uses a copper catalyst on a silica support promoted with chromium, zinc and barium.
[0134] In case of a catalytic gas-phase hydrogenation, nitrobenzene or a (di)nitro derivative of 1-methylbenzene is preferably hydrogenated in the presence of hydrogen and of at least one catalyst in a fluidized bed, preferably at a temperature of about 250 °C to about 300 °C. The pressure preferably ranges from of about 400 kPa to about 1000 kPa. The product gas stream is then cooled down and aniline or the (di)amino derivative of 1-methylbenzene which is then separated, preferably in a liquid-gas separator, from the product stream.
[0135] Liquid-phase hydrogenation of nitrobenzene to aniline or a (di)nitro derivative of 1-methylbenzene to the respective (di)amino derivative of 1-methylbenzene can be for example operated in a temperature range of about 90 °C to about 200 °C. Preferably, the pressure ranges from about 100 kPa to about 600 kPa. For example, slurry- or fluid- ized-bed reactors can be used for the liquid-phase hydrogenation of nitrobenzene in the presence of hydrogen and at least one catalyst. Suitable catalysts comprise nickel on a support such as for example kieselguhr. Further details of the manufacture of aniline from benzene are for example disclosed in G. Booth, Ullmann's Encyclopedia of Industrial Chemistry, Vol. 24, Chapter "Nitro Compounds, Aromatic”, pages 305 to 309, 2012 and the references cited therein and T. Kahl, K.-W. Schroder, F. R. Lawrence, W. J. Marshall, H. Hoke, R. Jackh, Ullmann's Encyclopedia of Industrial Chemistry, Vol. 3, Chapter "Aniline”, pages 467 to 470, 2012 and the references cited therein.
[0136] Further details of the manufacture of (di)amino derivatives of 1 -methylbenzene from 1 -methylebenzene by catalytic hydrogenation are for example disclosed in G. Booth, Ullmann's Encyclopedia of Industrial Chemistry, Vol. 24, Chapter "Nitro Compounds, Aromatic”, pages 309 to 313, 2012 and the references cited therein and P. F. Vogt, J. J. Gerulis, Ullmann's Encyclopedia of Industrial Chemistry, Vol. 2, Chapter "Amines, Aromatic”, pages 707 to 710, 2012 and the references cited therein.
[0137] In optional step c2), 1,1 '-Methylenebis(4-isocyanatobenzene) is manufactured from aniline via the diamine precursor 1 , 1 '-methylenebis(4-aminobenzene).
[0138] At least a portion of the aniline provided in in optional step c2) as starting material is manufactured in step d). The remaining aniline is manufactured from benzene not provided by steps a1) to a6). Such remaining aniline can be for example manufactured from benzene manufactured from fossil sources and / or from plastic waste or other feedstocks such as bio-oils by other methods.
[0139] Preferably, at least 2.5 wt.-%, more preferably at least 5.0 wt.-% and most preferably at least 7.5 wt.% of the benzene used for manufacture of aniline provided in optional step c2) is benzene 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 benzene used for manufacture of aniline provided in optional step c2) is manufactured by steps a1) to a6).
[0141] First, two equivalents of aniline are condensed with formaldehyde, preferably in the presence of hydrochloric acid as a catalyst, to form the diamine precursor 1,1 '-methylenebis(4-aminobenzene). Next, 1 , 1 -methylenebis(4- aminobenzene) is phosgenated with phosgene to form different isomers of 1,1 '-methylenebis(isocyanatobenzene). The phosgenation of 1,1 '-methylenebis(4-aminobenzene) can be for example made in liquid phase using an aromatic solvent in a batch process or a continuous process. The desired 1,1 '-methylenebis(4-isocyanatobenzene) is then separated from the phosgenation reaction products by a continuous thin-film distillation and / or by crystallization. Both processes are known as "splitting" (or, respectively, the equipment known as "splitters"). In addition to 1,1 '- methylenebis(isocyanatobenzene) also condensation products thereof can be formed thereby which are polyisocyanate derivatives of benzene. The residual crude product which comprises or consists of oligomeric 1,1 '-methylenebis(4-isocyanatobenzene) can be for example used for manufacture of rigid polyurethane or polyisocyanurate foams. The residual crude product is for example marketed as polymeric 1,1 '-methylenebis(4-isocyanatobenzene) (“PMDI”, poly-isocyanate derivatives of benzene) and contains, next to a residual level of monomers, oligomers and polymers of 1 , 1 '-methylenebis(4- isocyanatobenzene) with a broader distribution of chain lengths. Different PMDI grades vary by viscosity, functionality, and the like. PMDI also has various applications, such as polyisocyanurate rigid insulation foams from high viscous PMDI or such as polyurethane rigid insulation foams, woodbinders (e.g., particle board, OSB, MDF), appliance (fridges, freezers, cold chain in general), pipe insulation, transportation from low viscous PMDI.
[0142] The preparation of such diamine precursors from aniline and their phosgenation to 1 , 1 '-methylenebis(4- isocyanatobenzene) is for example described in C. Six, F. Richter, Ullmann's Encyclopedia of Industrial Chemistry, Vol. 20, Chapter "Isocyanates, Organic”, pages 70 to 76, 2012 and the references cited therein.
[0143] Di- and poly-isocyanate derivatives of benzene, 1-methylbenzene are manufactured from (di)amino derivatives of 1- methylbenzene by phosgenation with phosgene. The phosgenation of (di)amino derivatives of benzene and 1- methylbenzene can be for example made in liquid phase using an aromatic solvent in a batch process or a continuous process. The desired di- and / or poly-isocyanate derivative of benzene and 1-methylbenzene is then for example separated from the phosgenation reaction products by a continuous thin-film distillation and / or by crystallization. Both processes are known as "splitting" (or, respectively, the equipment known as "splitters").
[0144] Optionally, at least a portion of the phosgene used for manufacture of isomers of 1 , 1 '-methylenebis- (isocyanatobenzene) and di- and poly-isocyanate derivatives of benzene and / or 1-methylbenzene is produced from stream S5 by a process comprising the steps a) converting at least a portion of stream S5 by a partial oxidation reaction into a mixture comprising CO and H2, b) separating CO from said mixture and c) converting at least a portion of said CO in a catalytic gas phase reaction with chlorine in the presence of a catalyst into phosgene.
[0145] Phosgene is primarily produced from carbon monoxide and chlorine in a gas phase catalysis, usually over an activated carbon catalyst. Because of the exothermic reaction, the synthesis is carried out in cooled reactors, preferably in tube bundle reactors, the catalyst being filled in the reaction tubes and the cooling in the jacket space being effected by a liquid or boiling coolant medium.
[0146] Phosgene is produced in large-scale in a catalytic gas phase reaction of carbon monoxide and chlorine in the presence of a catalyst, for example, an activated carbon catalyst The reaction is strongly exothermic with a reaction enthalpy AH of -107.6 kJ / mol. To remove the reaction heat the reaction is normally carried out in tube-bundle reactors with catalyst filled inside the tubes (see Ullmann's Encyclopedia of industrial chemistry, Chapter ..Phosgene" 5thEd., Vol. A 19, p 413 ff., VCH Verlagsgesellschaft mbH, Weinheim, 1991). Generally, granular catalyst with a grain size in the range of from 3 to 5 mm is used in pipes with a typical inner diameter between 35 and 70 mm, typically between 39 and 45 mm. In the reaction, carbon monoxide is usually used in excess to ensure that all chlorine is converted, and largely chlorine-free phosgene is produced, since chlorine can lead to undesirable side reactions in the subsequent use of phosgene. The reaction can be carried out without pressure but is usually carried out at an overpressure of 200-600 kPa (2-6 bar). In this pressure range, the formed phosgene can be condensed after the reactor with cooling water or other heat carrier, for example organic heat carrier can be used, so that the condenser can be operated more economically.
[0147] At least a portion of the aniline or (di)amino derivative of 1-methylbenzene provided in in optional step d) as starting material is manufactured in step d). The remaining aniline or (di)amino derivative of 1-methylbenzene is manufactured from benzene or 1-methylbenzene not provided by steps a1) to a6). Such remaining aniline or (di)amino derivative of 1-methylbenzene can be for example manufactured from benzene or 1-methylbenzene manufactured from fossil sources and / or from plastic waste or other feedstocks such as bio-oils by other methods.
[0148] Preferably, at least 2.5 wt.-%, more preferably at least 5.0 wt.-% and most preferably at least 7.5 wt.% of the benzene or 1-methylbenzene used for manufacture of aniline or (di)amino derivative of 1-methylbenzene provided in optional step d) is benzene or 1-methylbenzene manufactured from a non-fossil feedstock.
[0149] Preferably, at least 2.5 wt.-%, more preferably at least 5.0 wt.-% and most preferably at least 7.5 wt.% of the benzene or 1-methylbenzene used for manufacture of aniline or (di)amino derivative of 1-methylbenzene provided in optional step d) is manufactured by steps a1) to a6).
[0150] The manufacture of di- and poly-isocyanate derivatives of benzene and 1-methylbenzene from benzene or 1- methylbenzene including the phosgenation of (di)amino derivatives of benzene and 1-methylbenzene to di- and polyisocyanate derivatives of 1-methylbenzene is for example described in C. Six, F. Richter, Ullmann's Encyclopedia of Industrial Chemistry, Vol. 20, Chapter "Isocyanates, Organic”, pages 70 to 76, 2012 and the references cited therein.
[0151] The amino derivative of benzene is aniline, and most preferably, aniline is converted in optional step c2) into 1,1 - methylenebis(4-aminobenzene) which can be then utilized as starting materials in step d) for manufacture of 1 , 1 '- methylenebis(4-isocyanatobenzene) therefrom.
[0152] The (di)amino derivatives of 1-methylbenzene are preferably selected from the group consisting of 2-amino-1- methylbenzene, 3-amino-1 -methylbenzene, 4-amino-1 -methylbenzene, 2, 4-diamino-1 -methylbenzene, 2,6-diamino- 1 -methylbenzene and mixtures thereof. Most preferably, the (di)amino derivatives of 1-methylbenzene is 2,4- diamino-1 -methylbenzene.
[0153] The di-isocyanate derivatives of 1-methylbenzene are preferably selected from the group consisting of 2-isocyanato- 1 -methylbenzene, 3-isocyanato-1 -methylbenzene, 4-isocyanato-, 2, 4-diisocyanato-1 -methylbenzene and 2,6- diisocyanato-1 -methylbenzene and mixtures thereof. Most preferably, the (di)isocyanate derivative of 1- methylbenzene is 2, 4-diisocyanato-1 -methylbenzene.
[0154] Polymers derived from isocyanate precursors such as polyurethanes (PUs), thermoplastic polyurethanes (TPUs), polyisocyanurates, and polyureas, which for example based on 1,1 '-methylenebis(4-isocyanatobenzene) or 2,4- diisocyanato-1 -methylbenzene, or poly-isocyanates (e.g., oligomers of di-isocyanato derivatives of benzene and 1- methylbenzene) ("building block”), can be for example manufactured in a continuous processes, solvent-based processes or solvent-free process in the presence of at least one further compound ("building block”) selected from the group comprising or consisting of polyesterpolyoles, polyetherpolyoles, polycarbonatepolyoles, polyetheresterpoly- oles, polyacrylatepolyoles, polyesterpolyacrylatepolyoles, diols, polycaprolactane polyols, polytetramethylene glycol, diamines, amino-terminated polyethers and mixtures thereof. Catalysts and additives used to support the desired reactions of the above-mentioned building blocks comprise Lewis-bases, Lewis-acids and insertion catalysts. Optionally, also chemical or physical blowing agents are added in case foams are produced (for example: cyclopentane, pentane, hydrofluoro-olefins (“HFOs”), HCOs, water).
[0155] The manufacture of polyurethanes (PUs), thermoplastic polyurethanes (TPUs), polyisocyanurates, and polyureas using 1,1 '-methylenebis(4-isocyanatobenzene) or a (di)isocyanate derivative of 1 -methylbenzene such as 2,4- diisocyanato-1-methylbenzene as a starting material is for example described in G. Brereton et al., Ullmann's Encyclopedia of Industrial Chemistry, Chapter "Polyurethanes”, pages 4 to 27, 2019 and the references cited therein.
[0156] The manufacture of polyurethanes (PUs), thermoplastic polyurethanes (TPUs), polyisocyanurates, and polyureas using 1, -methylenebis(4-isocyanatobenzene) or di- and poly-isocyanate derivatives of 1-methylbenzene such as 2, 4-diisocyanato-1 -methylbenzene as a starting material is for example described in T. Ouhadi, S. Abou-Sabet, H.-G. Wussow, L. M. Ryan, L. Plummer, F. E. Baumann, J. Lohmar, H. F. Vermeire, F. L. G. Malet, Ullmann's Encyclopedia of Industrial Chemistry, Chapter "Thermoplastic Elastomers”, pages 13 to 15, 2013 and the references cited therein.
[0157] At least a portion of the di- and / or poly-isocyanate derivatives of benzene and 1-methylbenzene used as building block for the optional synthesis of polyurethanes (PUs), thermoplastic polyurethanes (TPUs), polyisocyanurates, and polyureas therefrom are manufactured from benzene or 1-methylbenzene manufactured by steps a1) to a6).
[0158] Preferably, at least 2.5 wt.-%, more preferably at least 5.0 wt.-% and most preferably at least 7.5 wt.% of the benzene or 1-methylbenzene used for manufacture of the di- and / or poly-isocyanate derivatives of benzene and 1- methylbenzene and provided in optional step d) and / or the di- and / or poly-isocyanate derivatives of benzene or 1- methylbenzene used as building block for the synthesis of polyurethanes (PUs), thermoplastic polyurethanes (TPUs), polyisocyanurates, and polyureas were manufactured from benzene or 1-methylbenzene which was manufactured from a non-fossil feedstock. Preferably, at least 2.5 wt.-%, more preferably at least 5.0 wt.-% and most preferably at least 7.5 wt.% of the benzene or 1 -methylbenzene used for manufacture of the di- and / or poly-isocyanate derivatives of benzene and 1- methylbenzene are manufactured by steps a1) to a6).
[0159] The polyurethanes (PUs), thermoplastic polyurethanes (TPUs), polyisocyanurates, and polyureas comprising di- or multi-isocyanate building blocks which are manufactured from aniline and (di)amino derivatives of 1 -methylbenzene by the process according to the present invention can be used for different applications and markets which comprise: Insulation in appliance applications (such as in refrigerators, freezers, boilers, water heaters, cold storage), diverse applications in the automotive market (such as seating carpet backing, acoustics, steering wheels, panel skins, panel foams, headliner foam, headliner adhesive, coating adhesives, sealants, jounce bumpers, suspension mounts, ABS cables, ESP cables, interior skins), construction market (such as sandwich panels, spray foam, insulated doors, roller profiles, pipe insulation, wood binders, composite binders, laminate insulation boards, canned foam), footwear (casual shoes, safety shoes, sport shoes, synthetic leather, adhesives, soles for sport shoes, soles for safety shoes), furniture, upholstery and mattrasses.
[0160] 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 claims of the present invention.
[0161] 1 . Process for manufacturing aromatic amino compounds from benzene and 1 -methylbenzene comprising the steps a) providing benzene or 1 -methylbenzene and a mixture of nitric acid and sulfuric acid, b) contacting benzene or 1 -methylbenzene with the mixture of nitric acid and sulfuric acid whereby nitrobenzene or a nitro-derivative of 1 -methylbenzene is formed, d) hydrogenate the nitrobenzene or nitro-derivative of 1 -methylbenzene formed in step b) in the presence of hydrogen and, optionally, a catalyst, whereby aniline or an amino-derivative of 1 -methylbenzene is formed, characterized in that at least a portion of the benzene or 1 -methylbenzene provided in step a) is manufactured by 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 a portion or the 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 and / or 1 -methylbenzene from stream S6 in an aromatic hydrocarbon extraction unit AEU.
[0162] 2. Process according to embodiment 1 wherein preferably at least 2.5 wt.-%, more preferably at least 5.0 wt.-%, most preferably 7.5 wt.-% of the benzene or 1 -methylbenzene provided in step a) is manufactured by steps a1) to a6).
[0163] 3. Process according to embodiment 1 or 2 wherein the at least one pyrolysis oil is manufactured by a pyrolysis of plastic waste.
[0164] 4. Process according to any one of embodiments 1 to 3 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.
[0165] 5. Method according to any one of embodiments 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).
[0166] 6. Process according to any one of embodiments 1 to 5 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.
[0167] 7. Process according to any one of embodiments 1 to 6 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.
[0168] 8. Process according to any one of embodiments 1 to 7 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.
[0169] 9. Process according to any one of embodiments 1 to 8 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).
[0170] 10. Process according to any one of embodiments 1 to 9 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.
[0171] 11 . Process according to any one of embodiments 1 to 10 wherein the wherein the second hydroprocessing unit HU2 comprises at least one fixed-bed reactor.
[0172] 12. Process according to any one of embodiments 1 to 11 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.
[0173] 13. Process according to any one of embodiments 1 to 12 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. 14. Process according to any one of embodiments 1 to 13 wherein C6-C8 aromatic hydrocarbons are separated from stream S6 by extractive distillation in at least one aromatic hydrocarbon extraction unit AEU.
[0174] 15. Process according to any one of embodiments 1 to 14 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.
[0175] 16. Process according to any one of embodiments 1 to 15 wherein the nitro-derivative of 1 -methylbenzene formed in step b) is preferably selected from the group consisting of 2-nitro-1 -methylbenzene, 3-nitro-1 - methylbenzene, 4-nitro1 -methylbenzene, 2, 4-dinitro-1 -methylbenzene, and 2, 6-dinitro-1 -methylbenzene and mixtures thereof.
[0176] 17. Process according to any one of embodiments 1 to 16 wherein nitrobenzene or the nitro-derivative of 1- methylbenzeneis formed by an isothermal reaction at a temperature of about 50 °C to about 100 °C or by an adiabatic reaction at a temperature in the range of about 90 °C to about 190 °C.
[0177] 18. Process according to any of one of embodiments 1 to 17 wherein the amino-derivative of 1 -methylbenzene formed in step d) is preferably selected from the group consisting of 2-amino-1 -methylbenzene, 3-amino-1- methylbenzene, 4-amino-1-methylbenzene, 2, 4-amino-1 -methylbenzene, 2, 6-amino-1 -methylbenzene and mixtures thereof.
[0178] 19. Process according to any one of embodiments 1 to 18 wherein the hydrogen provided in step d) is manufactured by a process using at least partially energy from a renewable energy source.
[0179] 20. Process according to any one of embodiments 1 to 19 wherein the hydrogen provided in step d) is manufactured by water electrolysis using at least partially energy from a renewable energy source.
[0180] 21 . Process according to any one of embodiments 1 to 20 wherein the catalyst optionally employed in step d) is a copper and / or palladium catalyst on a support for gas-phase hydrogenation and nickel on a support for liquid-phase hydrogenation.
[0181] 22. Process according to any of embodiments 1 to 21 comprising the further step c2) converting aniline into 1,r-methylenebis(4-aminobenzene) by a condensation reaction in the presence of formaldehyde. 23. Process according to embodiment 22 wherein preferably at least 2.5 wt.-%, more preferably at least 5.0 wt.- %, most preferably 7.5 wt.-% of the aniline converted in step c2) is manufactured from benzene manufactured by steps a1) to a6).
[0182] 24. Process according to embodiment 22 or 23 wherein hydrochloric acid used as a catalyst in step c2).
[0183] 25. Process according to any of embodiments 22 to 24 further comprising the step d) phosgenating aniline or an amino-derivative of 1 -methylbenzene produced in step d), to form a di- or poly-isocyanate-derivative of 1 -methylbenzene, or phosgenating 1,1 '-methylenebis(4-aminobenzene) produced in step c2) with phosgene to form 1,1 '-methylenebis(4-isocyanatobenzene) or a polyisocyanate derivative thereof.
[0184] 26. Process according to embodiment 25 wherein at least a portion of the phosgene is produced from stream S5 by a process comprising the steps a) converting at least a portion of stream S5 by a partial oxidation reaction into a mixture comprising CO and H2, b) separating CO from said mixture and c) converting at least a portion of said CO in a catalytic gas phase reaction with chlorine in the presence of a catalyst into phosgene.
[0185] 27. Process according to embodiment 25 or 26 wherein the amino-derivative of 1 -methylbenzene produced in step d) is preferably selected from the group consisting of 2-amino-1 -methylbenzene, 3-amino-1- methylbenzene, 4-amino-1 -methylbenzene, 2, 4-diamino-1 -methylbenzene, 2, 6-diamino-1 -methylbenzene and mixtures thereof.
[0186] 28. Process according to any one of embodiments 25 to 27 wherein the di- or poly-isocyanate-derivative of 1- methylbenzene is preferably selected from the group consisting of 2-isocyanato-1 -methylbenzene, 3- isocyanato-1 -methylbenzene, 4-isocyanato-1 -methylbenzene, 2,4-diisocyanato-1-methylbenzene and 2,6- diisocyanato-1 -methylbenzene and mixtures thereof and poly-isocyanate derivatives thereof.
[0187] 29. Process according to any one of embodiments 25 to 28 wherein the isocyanates formed in step d) are further converted in the presence of at least one organic compound into a polymer selected from the group comprising or consisting of polyurethanes, thermoplastic polyurethanes, polyisocyanurates, and polyureas.
[0188] 30. Process according to any one of embodiments 29 wherein the at least one organic compound is selected from the group comprising or consisting of polyesterpolyoles, polyetherpolyoles, polycarbonatepolyoles, polyether- esterpolyoles, polyacrylatepolyoles, polyesterpolyacrylatepolyoles, diols, polycaprolactane polyols, polytetramethylene glycol, diamines, amino-terminated polyethers and mixtures thereof. 31. A chemical plant for manufacturing aromatic amino compounds from benzene and 1 -methylbenzene from a liquid stream comprising at least one pyrolysis oil, the chemical plant comprising
[0189] (i) at least one first hydroprocessing unit HU1, the at least one first hydroprocessing unit HU1
[0190] (ii) comprising at least one inlet and at least one outlet,
[0191] (iii) optionally a recycle unit downstream of and fluidically connected to the inlet and the outlet of the first hydroprocessing unit HU1,
[0192] (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,
[0193] (v) a second hydroprocessing unit HU2 downstream of and fluidically connected to the head outlet HO of the distillation unit DU,
[0194] (vi) at least one aromatic hydrocarbon extraction unit AEU which is downstream and fluidically connected to the second hydroprocessing unit HU2.
[0195] 32. Use of a chemical plant according to embodiment 31 for the process according to any one of embodiments 1 to 30.
[0196] 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.
[0197] The invention will be further explained by the following non-limiting examples.
[0198] Examples
[0199] The invention will be further explained by the following non-limiting examples.
[0200] 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.
[0201] Comparative example
[0202] 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.
[0203] The process conditions used for the first hydroprocessing unit HU1 are summarized in Table 1 :
[0204] he chosen compositions for the streams S1 , S1 S3, S4, S6, S7', S7", S7'" and S8 are summarized in Table 2: tream S1 ' = stream S1 + stream S2 + stream S3'.
[0205] 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.
[0206] The catalyst in the hydroprocessing unit HU 1 is a Ni-Mo catalyst on an alumina support taught in AU 2021 / 222788 A1.
[0207] 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.
[0208] 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.
[0209] 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.
[0210] The process conditions in the second hydroprocessing unit HU2 are summarized in Table 3: 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.
[0211] 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.
[0212] 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).
[0213] 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.
[0214] 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.
[0215] The results of the distillation in the distillation unit DU are shown in Table 4.
[0216] In the distillation unit DU, the light boiling fraction with most of the C6-C8 aromatic components goes overhead.
[0217] These are 78 wt.-% of the stream S4 to the distillation unit DU. The content of C6-C8 aromatic components is there- by 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. Example (inventive)
[0218] 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)).
[0219] Tab.5 process conditions in the first hydroprocessing unit HU1 :
[0220] 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'.
[0221] 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.
[0222] 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.
[0223] The results of the distillation in the distillation unit DU are shown in Table 7:
[0224] 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.
[0225] In the distillation unit DU, the light boiling fraction with most of the C6-C8 aromatic hydrocarbons go overhead.
[0226] 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.
[0227] 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.
[0228] The process conditions for the second hydroprocessing unit HU2 are shown in Tab. 8:
[0229] 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. 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).
[0230] 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 aromatic amino compounds from benzene and 1 -methylbenzene comprising the steps a) providing benzene or 1 -methylbenzene and a mixture of nitric acid and sulfuric acid, b) contacting benzene or 1 -methylbenzene with the mixture of nitric acid and sulfuric acid whereby nitrobenzene or a nitro-derivative of 1 -methylbenzene is formed, d) hydrogenate the nitrobenzene or nitro-derivative of 1 -methylbenzene formed in step b) in the presence of hydrogen and, optionally, a catalyst, whereby aniline or an amino-derivative of 1 -methylbenzene is formed, characterized in that at least a portion of the benzene or 1 -methylbenzene provided in step a) is manufactured by 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 a portion or the 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 and / or 1 -methylbenzene 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.-%, most preferably 7.5 wt.-% of the benzene or 1 -methylbenzene provided in step a) is manufactured by steps a1) to a6).
3. Process according to claim 1 or 2 wherein the at least one pyrolysis oil is manufactured by a pyrolysis of plastic waste.
4. Process according to any one of claims 1 to 3 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.
5. Method 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 nitro-derivative of 1 -methylbenzene formed in step b) is preferably selected from the group consisting of 2-nitro-1 -methylbenzene, 3-nitro-1-methylbenzene, 4- nitrol-methylbenzene, 2,4-dinitro-1-methylbenzene, and 2, 6-dinitro-1 -methylbenzene and mixtures thereof.
7. Process according to any of one of claims 1 to 6 wherein the amino-derivative of 1 -methylbenzene formed in step d) is preferably selected from the group consisting of 2-amino-1 -methylbenzene, 3-amino-1- methylbenzene, 4-amino-1-methylbenzene, 2, 4-amino-1 -methylbenzene, 2, 6-amino-1 -methylbenzene and mixtures thereof.
8. Process according to any of claims 1 to 7 comprising the further step c2) converting aniline into 1,r-methylenebis(4-aminobenzene) by a condensation reaction in the presence of formaldehyde.
9. Process according to any of claim 7 or 8 further comprising the step d) phosgenating aniline or an amino-derivative of 1 -methylbenzene produced in step d), to form a di- or poly-isocyanate-derivative of 1 -methylbenzene, or phosgenating 1,r-methylenebis(4-aminobenzene) produced in step c2) with phosgene to form 1,1 '-methylenebis(4-isocyanatobenzene) or a polyisocyanate derivative thereof.
10. Process according to claim 9 wherein the amino-derivative of 1 -methylbenzene produced in step d) is preferably selected from the group consisting of 2-amino-1 -methylbenzene, 3-amino-1 -methylbenzene, 4-amino-1- methylbenzene, 2, 4-diamino-1 -methylbenzene, 2,6-diamino-1-methylbenzene and mixtures thereof.11 . Process according to claim 9 or 10 wherein the di- or poly-isocyanate-derivative of 1 -methylbenzene is preferably selected from the group consisting of 2-isocyanato-1 -methylbenzene, 3-isocyanato-1 -methylbenzene, 4- isocyanato-1 -methylbenzene, 2, 4-diisocyanato-1 -methylbenzene and 2, 6-diisocyanato-1 -methylbenzene and mixtures thereof and poly-isocyanate derivatives thereof.
12. Process according to any one of claims 9 to 11 wherein the isocyanates formed in step d) are further converted in the presence of at least one organic compound into a polymer selected from the group comprising or consisting of polyurethanes, thermoplastic polyurethanes, polyisocyanurates, and polyureas.
13. Process according to claim 12 wherein the at least one organic compound is selected from the group comprising or consisting of polyesterpolyoles, polyetherpolyoles, polycarbonatepolyoles, polyetheresterpolyoles, poly- acrylate-polyoles, polyesterpolyacrylatepolyoles, diols, polycaprolactane polyols, polytetramethylene glycol, diamines, amino-terminated polyethers and mixtures thereof.
14. A chemical plant for manufacturing aromatic amino compounds from benzene and 1 -methylbenzene 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.
Citation Information
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