Recovery of aliphatic hydrocarbons

Abstract

The present invention relates to a process for recovering aliphatic hydrocarbons from a liquid stream containing aliphatic hydrocarbons, heteroatom-containing organic compounds, and optionally aromatic hydrocarbons, comprising: a) contacting the liquid stream with a wash solvent to remove heteroatom-containing organic compounds; and a) liquid-liquid extraction of the washed stream with an extraction solvent, wherein during step a), and / or between steps a), and / or between steps a) and b), and / or after step b), the heteroatom-containing organic compounds, optional aromatic hydrocarbons, and optional other contaminants are removed from the liquid stream, and / or from the washed stream obtained from step a), and / or from the raffinate stream obtained from step b), respectively, by contacting the latter stream with a sorbent. Furthermore, the present invention relates to a process for recovering aliphatic hydrocarbons from plastics, including the above process, and a process for steam cracking a hydrocarbon feed containing aliphatic hydrocarbons as recovered in one of the above processes.

Description

[Technical Field]

[0001] The present invention relates to a process for recovering aliphatic hydrocarbons from a liquid hydrocarbon feed stream containing aliphatic hydrocarbons, heteroatom-containing organic compounds, and optionally aromatic hydrocarbons; a process for recovering aliphatic hydrocarbons from plastics, including the above process; and a process for vapor decomposition of a hydrocarbon feed containing aliphatic hydrocarbons such that they are recovered in one of the above processes. [Background technology]

[0002] Waste plastics can be converted into high-value chemicals, including olefins and aromatic hydrocarbons, through, for example, thermal decomposition of the plastics. Thermal decomposition of plastics can yield a product stream containing hydrocarbons with a wide boiling point range. Hydrocarbons from such thermal decomposition product streams can be further decomposed in a vapor decomposition unit to produce high-value chemicals, including ethylene and propylene, which are monomers that can be used in the production of new plastics.

[0003] International Publication No. 2020 / 212315 discloses a process for recovering aliphatic hydrocarbons from a liquid hydrocarbon feed stream containing aliphatic hydrocarbons and further containing aromatic hydrocarbons and / or polar components, the process comprising: feeding a feed stream and an organic solvent stream into a column; contacting the feed stream with the organic solvent stream; and recovering the aliphatic hydrocarbons by liquid-liquid extraction of the aromatic hydrocarbons and / or polar components with the organic solvent.

[0004] According to the aforementioned International Publication No. 2020 / 212315, the liquid hydrocarbon feedstock stream may include liquid products generated by the thermal decomposition of plastic waste. Furthermore, according to International Publication No. 2020 / 212315, the organic solvent may be selected from the group consisting of diols and triols (including any isomers of monoethylene glycol, monopropylene glycol, and butanediol); glycol ethers (including oligoethylene glycols including diethylene glycol and tetraethylene glycol, and their ethers (including diethylene glycol dimethyl ether)); amides (including N-alkylpyrrolidones including N-methylpyrrolidone, and dialkylformamides including dimethylformamide); dialkyl sulfoxides (including dimethyl sulfoxide); sulfolanes; N-formylmorpholine (NFM); and furan ring-containing components (including furfural, 2-methylfuran, and furfuryl alcohol).

[0005] Furthermore, U.S. Patent Application Publication 2018 / 0355256 discloses a method for extracting fuel from plastics, the method comprising subjecting a certain amount of plastic to a pyrolysis process, thereby converting at least a portion of the plastic into crude fuel, and extracting the fuel in a readily usable form by 1) a first extraction step comprising countercurrent liquid-liquid extraction using one or more extraction solvents to extract one or more impurities from the crude fuel, and 2) a second extraction step comprising countercurrent extraction of the contaminated extraction solvents obtained from the first extraction step. In the process shown in Figure 2 of U.S. Patent Application Publication 2018 / 0355256, the crude fuel produced by the pyrolysis of plastics (i.e., crude diesel) is first subjected to extraction with N-methyl-2-pyrrolidone (NMP) to extract one or more impurities, including sulfur compounds and aromatics, from the crude fuel. Next, the contaminated NMP from the first extraction step is subjected to a second extraction step using water to increase the polarity of the contaminated extraction solvent, thereby separating the impurities. In the final step, the water-contaminated NMP from the second extraction step is distilled using a standard distillation column to produce recirculated water and recirculated NMP.

[0006] In the process described in U.S. Patent Application Publication No. 2018 / 0355256 above, a certain amount of heteroatom-containing organic contaminants can be removed from the crude fuel (supply material) in the first extraction step. However, the resulting refined fuel may still contain relatively large amounts of these contaminants, which is of particular concern when such purified oil is supplied to a steam cracker instead of being used as fuel, as these contaminants adversely affect the yield, selectivity, and reliability of the steam cracker.

[0007] In addition, such crude feed materials may contain other contaminants, such as silicon-containing compounds, such as silica and siloxane compounds. For example, silica is known for its use as a filler to improve the mechanical properties of plastics, such as glass fiber (SiO2). Furthermore, the siloxane compound may be derived from a polysiloxane polymer containing a -R-2Si-O-SiR2- chain. Such silicon-containing compounds may not be removed by the extraction solvent (such as NMP) and thus may eventually reach the raffinate stream. Furthermore, other contaminants in such crude feed materials may be metals. For example, calcite (CaCO3) and wollastonite (CaSiO3) are also known for their use as fillers in plastics. Some of these metals may not reach the extract stream but may form complexes with the extraction solvent and instead reach the raffinate stream. Such silicon-containing compounds from the raffinate stream also have adverse effects due to tubular furnace fouling that they may cause in the steam cracking reactor if they are present in the feed to the steam cracking reactor.

[0008] In general, for some heteroatom-containing organic contaminants, particularly chloride, nitrogen, and / or oxygen-containing contaminants, as well as other contaminants such as the silicon-containing compounds and metals mentioned above, there are certain specifications (maximum concentrations) that must be met before the hydrocarbon feedstock can be supplied to the vapor cracking unit.

[0009] A crude feed for an extraction process may exist, such as that disclosed in U.S. Patent Application Publication No. 2018 / 0355256, which contains such a large amount of heteroatom-containing organic contaminants and any other contaminants, such as pyrolysis oil made from waste plastics, that applying such an extraction process alone would not yield a refined feed (for example, to a steam cracker) of sufficient quality to meet the above specifications.

[0010] In addition, the extraction process may involve the "accumulation" of these contaminants in the recirculated water (extraction solvent in the second extraction step) and the recirculated NMP (extraction solvent in the first extraction step), which ultimately leads to a further reduction in the quality of the final purified product.

[0011] The accumulation of the above-mentioned contaminants may be caused by the water extraction solvent in the process described in U.S. Patent Application Publication No. 2018 / 0355256, which extracts some of the contaminants in the second extraction step in addition to the NMP to be extracted. As a result, the feed to the distillation column (Figure 2 of U.S. Patent Application Publication No. 2018 / 0355256) may still contain certain amounts of heteroatom-containing organic contaminants, particularly oxygen-containing organic contaminants, specifically more polar components including, for example, phenol. The distillation may result in some of the contaminants being separated with the recirculated water because the water and such contaminants may form an azeotrope, thereby degrading the quality of the water recirculation flow. If the recirculated water is recirculated to the column used in the second extraction step, the concentration of these contaminants in the recirculated water will increase (accumulate) in addition to the accumulation of these contaminants in the recirculated NMP used in the first extraction step. This may result in reduced efficiency in the first and second extraction steps. Such accumulation of these contaminants (in the recirculated NMP) could result in the purified oil still containing relatively large amounts of these contaminants, which is of particular concern when such purified oil is supplied to a steam cracking unit.

[0012] Furthermore, in practice, the feedstock may include other contaminants such as salts, particularly liquid hydrocarbon feedstock flows obtained from the thermal decomposition of plastics. For example, such feedstocks may contain calcite (CaCO3) and wollastonite (CaSiO3), as discussed above. Such salts may reach the extraction stream if, for example, the extraction solvent is NMP, as used in column A of the process in Figure 2 of U.S. Patent Application Publication No. 2018 / 0355256. Subsequently, such salts reach the water-NMP bottom stream from column B used in the process, then enter distillation column C, where they are concentrated in the NMP bottom stream. The salts are then recycled together with the NMP, and their concentrations increase over time. Furthermore, since NMP and other organic solvents have limited solubility for the salts, they begin to precipitate in the distillation column, leading to column fouling.

[0013] There is an ongoing need to develop improved processes for recovering aliphatic hydrocarbons from liquid streams containing aliphatic hydrocarbons, heteroatom-containing organic compounds, and optionally aromatic hydrocarbons, the liquid streams of which may result from the decomposition of waste plastics in certain mixed waste plastics, particularly before feeding such recovered aliphatic hydrocarbons into a vapor cracking unit. An object of the present invention is to provide such a process for recovering aliphatic hydrocarbons from such liquid streams, which is technically advantageous, efficient and affordable, and in particular, does not have one or more of the above-mentioned drawbacks, as discussed above in relation to U.S. Patent Application Publication No. 2018 / 0355256. Such a technically advantageous process would preferably result in relatively low energy demands and / or relatively low capital expenditures. [Prior art documents] [Patent Documents]

[0014] [Patent Document 1] International Publication No. 2020 / 212315 [Patent Document 2] U.S. Patent Application Publication No. 2018 / 0355256 [Overview of the Initiative]

[0015] Surprisingly, such a process is a) to contact a liquid stream containing aliphatic hydrocarbons, heteroatom-containing organic compounds, and optionally aromatic hydrocarbons with a washing solvent a) containing one or more heteroatoms to remove the heteroatom-containing organic compounds, and b) to liquid-liquid extract the stream obtained from the washing step a) containing aliphatic hydrocarbons, heteroatom-containing organic compounds, and optionally aromatic hydrocarbons with an extraction solvent b) containing one or more heteroatoms, wherein (i) during step a) at least a portion of the liquid feed stream is contacted with an sorbent (or adsorbent), and / or (ii) during multiple steps a) aliphatic hydrocarbons, heteroatom-containing organic compounds, and The inventors have found that this can be provided by liquid-liquid extraction, in which at least a portion of the flow obtained from the preceding step a), which optionally contains aromatic hydrocarbons, is brought into contact with an sorbent, and / or (iii) between steps a) and b), at least a portion of the flow obtained from step a), which optionally contains aliphatic hydrocarbons, heteroatom-containing organic compounds, and aromatic hydrocarbons, is brought into contact with an sorbent, and / or (iv) after step b), at least a portion of the raffinate flow obtained from step b), which contains aliphatic hydrocarbons and heteroatom-containing organic compounds, is brought into contact with an sorbent, and the sorbent removes at least a portion of the heteroatom-containing organic compounds from the latter flow.

[0016] Accordingly, the present invention relates to a process for recovering aliphatic hydrocarbons from a liquid hydrocarbon feed stream containing aliphatic hydrocarbons, heteroatom-containing organic compounds, and optionally aromatic hydrocarbons, the process being: a) Mixing at least a portion of the liquid hydrocarbon feed stream with a washing solvent a) containing one or more heteroatoms, and separating the resulting mixture into a first stream containing the washing solvent a) and the heteroatom-containing compound, and a second stream containing aliphatic hydrocarbons, heteroatom-containing organic compounds, and optionally aromatic hydrocarbons, b) bringing at least a portion of the second flow obtained from step a) into contact with an extraction solvent b) containing one or more heteroatoms, and subjecting the flow to liquid-liquid extraction with the extraction solvent b) to obtain a first flow containing aliphatic hydrocarbons and optionally heteroatom-containing organic compounds, and a second flow containing the extraction solvent b), heteroatom-containing organic compounds, and optionally aromatic hydrocarbons, (i) During step a), before the first and second flows are separated in step a), at least a portion of the liquid hydrocarbon feed stream is brought into contact with the sorbent, and / or (ii) Between the preceding step a) and the subsequent step a), at least a portion of the second flow obtained from the preceding step a) is brought into contact with the sorbent, and / or (iii) Between steps a) and b), at least a portion of the second flow obtained from step a) is brought into contact with the sorbent, and / or (iv) The first stream obtained from step b) contains an aliphatic hydrocarbon and a heteroatom-containing organic compound, and after step b) at least a portion of the stream is brought into contact with the sorbent.

[0017] Advantageously, in the present invention, heteroatom-containing organic compounds and optionally other contaminants, which can be obtained by applying only an extraction step, are removed by the washing and sorption steps in the process of the present invention. This then advantageously can result in a final hydrocarbon product of sufficiently high quality that meets certain specifications (maximum concentrations) for many heteroatom-containing organic contaminants, particularly chloride, nitrogen, and / or oxygen-containing contaminants, and any other contaminants that must be met before the hydrocarbon feed can be supplied to the steam cracking unit. In this specification, “other contaminants” other than heteroatom-containing organic contaminants (heteroatom-containing organic compounds) in or derived from the liquid hydrocarbon feedstream means contaminants that may include salts, and / or silicon-containing compounds, and / or metals, in or derived from the liquid hydrocarbon feedstream.

[0018] Furthermore, advantageously, heteroatom-containing organic compounds, particularly oxygen-containing organic contaminants, specifically some of the more polar components including, for example, phenol, are removed in the washing step a) preceding the extraction step b), in which at least a portion of the liquid hydrocarbon feed stream is brought into contact with the washing solvent a), thereby avoiding or reducing the accumulation of such contaminants in the downstream portion of the process. Furthermore, advantageously, any other contaminants from the feed stream are also removed in the washing step a), thereby preventing the accumulation of some of these other contaminants, including salts, in the downstream section to higher concentrations, thereby simultaneously preventing fouling of the downstream distillation column due to the precipitation of such salts.

[0019] Furthermore, the extracted heteroatom-containing organic compounds and optionally the other contaminants in the second (extraction) stream obtained from step b), which includes the extraction solvent b), the heteroatom-containing organic compounds, and optionally aromatic hydrocarbons, may accumulate in the optional recirculated extraction solvent b) stream to step b), as discussed above. The heteroatom-containing organic compounds causing such accumulation may include the component with the highest polarity among all the heteroatom-containing organic compounds extracted in step b) of the process. In such cases, advantageously, the sorption step (iv) following the extraction step b) in the process of the present invention may then still deliver, for example, to a vapor cracking unit, a relatively pure final hydrocarbon product substantially free of heteroatom-containing organic compounds and optionally other contaminants. Furthermore, through washing step a), and through sorption step (i) during washing step a), and / or sorption step (ii) between multiple washing steps a), and / or sorption step (iii) after washing step a) and before extraction step b), some of these heteroatom-containing organic compounds and other optional contaminants are already removed from the feed stream before being subjected to extraction step b), thereby preventing such accumulation in the recirculated stream of any extraction solvent b). The relatively pure stream of extraction solvent b) can then be advantageously recirculated to step b) and used to extract further heteroatom-containing organic compounds and optional aromatic hydrocarbons from the new feed. Accordingly, in the present invention, the aforementioned contaminants, including heteroatom-containing organic compounds, and any other contaminants, including any salts that accumulate or may accumulate as discussed above, are advantageously already removed in the washing step a) preceding the extraction step b) and can be concentrated in the sorbent used in the sorbent steps (i), (ii), (iii) and / or (iv), thereby preventing the accumulation of such contaminants in any recirculated stream in the process and ultimately yielding a relatively pure final hydrocarbon product.

[0020] (i) Due to the combination of the above pre-washing step a) and (ii) the above use of the sorbent before and / or after the extraction step b), the present invention does not require, or substantially reduces the need to apply, other cumbersome methods to mitigate the accumulation of these contaminants. For example, it is not necessary, or substantially reduced, to bleed a portion of any recirculating stream (e.g., any recirculating extraction solvent stream b) before recirculation, so that (i) such a bleed stream is discarded, resulting in a loss of extraction solvent, or (ii) the extraction solvent can be recovered from such a bleed stream, for example, by distillation, but that is cumbersome.

[0021] In addition, in the washing step a) of the process of the present invention, other contaminants that should not reach the raffinate stream obtained from the extraction step b) can also be advantageously removed simultaneously with the heteroatom-containing organic contaminants and optional salts. For example, silicon-containing compounds such as silica and siloxane compounds can also be advantageously removed in step a) of the process, thereby preventing any adverse effects that such contaminants may have in subsequent processes such as steam decomposition processes.

[0022] Furthermore, the present invention relates to a process for recovering aliphatic hydrocarbons from plastics, wherein at least a portion of the plastic contains a heteroatom-containing organic compound, and the process is (I) A step of decomposing the plastic and recovering hydrocarbon products including aliphatic hydrocarbons, heteroatom-containing organic compounds, and optionally aromatic hydrocarbons, (II) The step of subjecting a liquid hydrocarbon feed stream containing at least a portion of the hydrocarbon product obtained in step (I) to the above process for recovering aliphatic hydrocarbons from the liquid hydrocarbon feed stream.

[0023] Furthermore, the present invention relates to a process for vapor decomposition of a hydrocarbon feedstock, wherein the hydrocarbon feedstock comprises aliphatic hydrocarbons recovered in one of the above processes for the recovery of aliphatic hydrocarbons. [Brief explanation of the drawing]

[0024] [Figure 1] This document illustrates one embodiment of a process for recovering aliphatic hydrocarbons according to the present invention. [Figure 2] Another embodiment of the above process is shown. [Modes for carrying out the invention]

[0025] Each of the processes of the present invention comprises a plurality of steps. In addition, the process may include one or more intermediate steps between consecutive steps. Furthermore, the process may include one or more additional steps before the first step and / or after the last step. For example, if the process comprises steps a), b), and c), the process may include one or more intermediate steps between steps a) and b) and between steps b) and c). Furthermore, the process may include one or more additional steps before step a) and / or after step c).

[0026] Within this specification, phrases such as “step y) includes providing at least a portion of the flow obtained from step x) to ” mean “step y) includes providing some or all of the flow obtained from step x) to ” or similarly, “step y) includes providing part or all of the flow obtained from step x). For example, the flow obtained from step x) may be divided into one or more parts, and at least one of these parts may be provided to step y). Furthermore, for example, the flow obtained from step x) may be provided to an intermediate step between step x) and step y) to obtain a further flow, of which at least a portion may be provided to step y).

[0027] The processes of the present invention, as well as the flows and compositions used in such processes, are described by the terms “comprising,” “containing,” or “including” one or more of the various described steps and components, but they may also “essentially consist of” or “consist of” such one or more of the various described steps and components.

[0028] In the context of the present invention, if the flow contains two or more components, these components should be selected in an amount not exceeding 100% of the total.

[0029] Furthermore, if upper and lower limits are cited for a property, the range of values ​​defined by a combination of either the upper limit or the lower limit is also included.

[0030] Within this specification, “substantially none” with respect to the amount of a particular component in a flow means an amount of the component in question that is at most 1,000, preferably at most 500, more preferably at most 100, more preferably at most 50, more preferably at most 30, more preferably at most 20, and most preferably at most 10 ppmw (parts per million by weight) based on the amount (i.e., weight) of the flow.

[0031] In this specification, “top flow” or “bottom flow” from a column refers to the flow exiting the column at a position 0% to 30%, more preferably 0% to 20%, or even more preferably 0% to 10%, based on the total length of the column, from the top or bottom of the column, respectively.

[0032] Unless otherwise specified, when a boiling point is referenced herein, it means the boiling point at a pressure of 760 mmHg (101.3 kPa).

[0033] Within this specification, the term "heteroatom-containing compound" refers to heteroatom-containing inorganic compounds, including heteroatom-containing organic compounds and / or salts.

[0034] Liquid hydrocarbon feedstock flow In the present invention, the liquid hydrocarbon supply stream includes aliphatic hydrocarbons, heteroatom-containing organic compounds, and optionally aromatic hydrocarbons.

[0035] Preferably, the liquid hydrocarbon feed stream contains both aliphatic hydrocarbons having a boiling point of 30 to 300°C and aliphatic hydrocarbons having a boiling point greater than 300 to 600°C in a weight ratio of 99:1 to 1:99. The amount of aliphatic hydrocarbons having a boiling point of 30 to 300°C may be a maximum of 99% by weight, a maximum of 80% by weight, a maximum of 60% by weight, a maximum of 40% by weight, a maximum of 30% by weight, a maximum of 20% by weight, or a maximum of 10% by weight, based on the total amount of aliphatic hydrocarbons having a boiling point of 30 to 600°C. Furthermore, the amount of aliphatic hydrocarbons having a boiling point of 30 to 300°C may be at least 1% by weight, at least 5% by weight, at least 10% by weight, at least 20% by weight, or at least 30% by weight, based on the total amount of aliphatic hydrocarbons having a boiling point of 30 to 600°C.

[0036] Therefore, advantageously, the liquid hydrocarbon feedstock stream can contain varying amounts of aliphatic hydrocarbons within a wide boiling point range of 30 to 600°C. Thus, similar to the boiling point, the carbon number of the aliphatic hydrocarbons in the liquid hydrocarbon feedstock stream can also vary over a wide range, for example, between 5 and 50 carbon atoms. The carbon number of the aliphatic hydrocarbons in the liquid hydrocarbon feedstock stream can be at least 4, or at least 5, or at least 6, and at most 50, or at most 40, or at most 30, or at most 20.

[0037] The amount of aliphatic hydrocarbons in the liquid hydrocarbon feed stream may be at least 30% by weight, or at least 50% by weight, or at least 80% by weight, or at least 90% by weight, or at least 95% by weight, or at least 99% by weight, and may be less than 100% by weight, or at most 99% by weight, or at most 90% by weight, or at most 80% by weight, or at most 70% by weight. The aliphatic hydrocarbons may be cyclic, linear, or branched.

[0038] Aliphatic hydrocarbons in the liquid hydrocarbon feedstock stream may include non-olefinic (paraffinic) and olefinic aliphatic compounds. The amount of paraffinic aliphatic compounds in the liquid hydrocarbon feedstock stream may be at least 20% by weight, at least 40% by weight, at least 60% by weight, or at least 80% by weight, based on the total weight of the liquid hydrocarbon feedstock stream, and may be less than 100% by weight, or at most 99% by weight, or at most 80% by weight, or at most 60% by weight. Furthermore, the amount of olefinic aliphatic compounds in the liquid hydrocarbon feedstock stream may be less than 100% by weight, or at least 20% by weight, at least 40% by weight, at least 60% by weight, or at least 80% by weight, based on the total weight of the liquid hydrocarbon feedstock stream, and may be at most 99% by weight, or at most 80% by weight, or at most 60% by weight.

[0039] Furthermore, the olefinic compounds may include aliphatic compounds having one carbon-carbon double bond (monoolefins) and / or aliphatic compounds having two or more carbon-carbon double bonds, the latter of which may be conjugated or unconjugated. That is, the two or more carbon-carbon double bonds may be conjugated or unconjugated. The aliphatic compounds having two or more carbon-carbon double bonds may include compounds having double bonds at the alpha and omega positions. The amount of monoolefin in the liquid hydrocarbon feedstock stream may be at least 20% by weight, at least 40% by weight, at least 60% by weight, or at least 80% by weight, based on the total weight of the liquid hydrocarbon feedstock stream, and may be less than 100% by weight or at most 99% by weight, at most 80% by weight, or at most 60% by weight. Furthermore, the amount of conjugated aliphatic compounds having two or more carbon-carbon double bonds in the liquid hydrocarbon feedstock stream may be greater than 0% by weight, or at least 10% by weight, or at least 20% by weight, or at least 40% by weight, or at least 60% by weight, and may be up to 80% by weight, or up to 60% by weight, or up to 40% by weight, based on the total weight of the liquid hydrocarbon feedstock stream.

[0040] In this specification, an aliphatic hydrocarbon containing one or more heteroatoms is referred to as a "heteroatom-containing organic compound," as further described below. Unless otherwise explicitly or contextually indicated, the term "aliphatic hydrocarbon" in this specification does not include heteroatom-containing aliphatic hydrocarbons. Furthermore, unless otherwise explicitly or contextually indicated, the term "aliphatic hydrocarbon" in this specification does not include conjugated aliphatic compounds having two or more carbon-carbon double bonds.

[0041] In addition to the aliphatic hydrocarbons mentioned above, the liquid hydrocarbon feedstock stream also contains heteroatom-containing organic compounds and optionally aromatic hydrocarbons.

[0042] The amount of aromatic hydrocarbons in the liquid hydrocarbon feedstock stream may be 0% by weight, greater than 0% by weight, or at least 5% by weight, or at least 10% by weight, or at least 15% by weight, or at least 20% by weight, or at least 25% by weight, or at least 30% by weight, and may be up to 50% by weight, or at most 40% by weight, or at most 30% by weight, or at most 20% by weight. Aromatic hydrocarbons may include monocyclic and / or polycyclic aromatic hydrocarbons. An example of a monocyclic aromatic hydrocarbon is styrene. Polycyclic aromatic hydrocarbons may include non-condensed and / or condensed polycyclic aromatic hydrocarbons. An example of a non-condensed polycyclic aromatic hydrocarbon is oligostyrene. Styrene and oligostyrene may be derived from polystyrene. Examples of condensed polycyclic aromatic hydrocarbons are naphthalene and anthracene, as well as alkylnaphthalene and alkylanthracene. One or more aromatic rings in an aromatic hydrocarbon may be substituted with one or more hydrocarbyl groups, including alkyl groups (saturated) and alkylene groups (unsaturated).

[0043] In this specification, aromatic hydrocarbons containing one or more heteroatoms are referred to as “heteroatom-containing organic compounds,” as further described below. Unless otherwise explicitly or by context, the term “aromatic hydrocarbons” in this specification does not include heteroatom-containing aromatic hydrocarbons.

[0044] Furthermore, the amount of heteroatom-containing organic compounds in the liquid hydrocarbon feedstock stream is greater than 0% by weight, and can be at least 0.5% by weight, or at least 1% by weight, or at least 3% by weight, or at least 5% by weight, or at least 10% by weight, or at least 15% by weight, or at least 20% by weight, and can be up to 30% by weight, or up to 20% by weight, or up to 10% by weight, or up to 5% by weight.

[0045] The heteroatom-containing organic compound in the liquid hydrocarbon feedstock stream contains one or more heteroatoms, preferably oxygen, nitrogen, sulfur, and / or halogens (e.g., chlorine). The heteroatom-containing organic compound may also contain one or more of the following: amines, imines, nitriles, alcohols, ethers, ketones, aldehydes, esters, acids, amides, carbamates (sometimes called urethanes), and ureas.

[0046] Furthermore, the above heteroatom-containing organic compounds may be aliphatic or aromatic. An example of an aliphatic heteroatom-containing organic compound is oligomeric polyvinyl chloride (PVC). Oligomer PVC may be derived from polyvinyl chloride. Aromatic heteroatom-containing organic compounds may include monocyclic and / or polycyclic aromatic heteroatom-containing organic compounds. Examples of monocyclic aromatic heteroatom-containing organic compounds are terephthalic acid and benzoic acid. An example of a polycyclic aromatic heteroatom-containing organic compound is oligomeric polyethylene terephthalate (PET). Terephthalic acid, benzoic acid, and oligomeric PET may be derived from polyethylene terephthalate. Examples of nitrogen-containing organic compounds are compounds derived from polyamides, including polyurethane and nylon.

[0047] Unless otherwise explicitly indicated or contextually indicated, the term “heteroatom-containing organic compound” in this specification means a heteroatom-containing organic compound in or derived from a liquid hydrocarbon feedstock stream. Furthermore, unless otherwise explicitly indicated or contextually indicated, the term “heteroatom-containing organic compound” in this specification does not include the extraction solvent and / or washing solvent as defined herein.

[0048] Additionally, the liquid hydrocarbon feedstock stream may contain salts. These salts may include organic and / or inorganic salts. The salts may contain ammonium, alkali metals, alkaline earth metals, or transition metals as cations, and carboxylic acids, sulfuric acids, phosphoric acids, or halides as anions.

[0049] Furthermore, the liquid hydrocarbon feedstock stream may also contain silica and silicon-containing compounds such as siloxane compounds.

[0050] Furthermore, it should be noted that the liquid hydrocarbon feedstock stream may contain metals.

[0051] Preferably, at least a portion of the components in the liquid hydrocarbon feedstock stream, which include aliphatic hydrocarbons, heteroatom-containing organic compounds, and optionally aromatic hydrocarbons, are synthetic compounds and not natural compounds, such as those found in petroleum. For example, such synthetic compounds include compounds derived from the thermal decomposition of plastics synthesized from biomass, such as polyethylene synthesized by the dehydration of ethanol from bioethanol and the subsequent polymerization of the ethylene thus formed.

[0052] Furthermore, since heteroatom-containing organic compounds and any other contaminants are easily removed in this process, the feed to this process can advantageously tolerate relatively large amounts of such heteroatom-containing organic compounds and other contaminants. Therefore, waste plastics that can be pyrolyzed to produce feedstock for this process may include heteroatom-containing plastics such as polyvinyl chloride (PVC), polyethylene terephthalate (PET), and polyurethane (PU). Specifically, mixed waste plastics containing relatively large amounts of such heteroatom-containing plastics, in addition to heteroatom-free plastics such as polyethylene (PE) and polypropylene (PP), can be pyrolyzed.

[0053] Step a) Pre-cleaning of the liquid hydrocarbon feed stream. In step a) of this process, prior to the extraction step b), heteroatom-containing organic compounds and optionally other contaminants are removed from the liquid hydrocarbon feed stream by contacting at least a portion of the stream with the washing solvent a). Therefore, step a) precedes the extraction step b) of this process. Step a) includes mixing at least a portion of the liquid hydrocarbon feed stream with the washing solvent a), and separating the resulting mixture into a first stream containing the washing solvent a), heteroatom-containing compounds, and optionally other contaminants, and a second stream containing aliphatic hydrocarbons, heteroatom-containing organic compounds, and optionally aromatic hydrocarbons. At least a portion of the second stream obtained from step a) is supplied to step b), i.e., contacted with the extraction solvent b) in step b).

[0054] Furthermore, in this process, step a) may be performed multiple times consecutively, i.e., at least twice, preferably two or three times, more preferably twice. The latter means that a second stream obtained from the first step a) (or a preceding step a)) containing aliphatic hydrocarbons, heteroatom-containing organic compounds, optionally other contaminants, and optionally aromatic hydrocarbons is sent to a second step a) (or a subsequent step a)) where further heteroatom-containing organic compounds and optionally other contaminants are removed from the second stream by contacting at least a portion of the stream with washing solvent a), and this second step a) also mixes at least a portion of the stream with washing solvent a), and separates the resulting mixture into a first stream containing washing solvent a), heteroatom-containing compounds, and optionally other contaminants, and a second stream containing aliphatic hydrocarbons, heteroatom-containing organic compounds, and optionally aromatic hydrocarbons. At least a portion of the second flow obtained from the second step a) is supplied to step b), that is, to be brought into contact with the extraction solvent b) in step b), or supplied to a further step a). Furthermore, at least a portion of the first flow obtained from the second step a) (or from any subsequent step a)) may be supplied to the first step a) (or any preceding step a)) in order to provide the washing solvent a) to such first or preceding step a)).

[0055] Depending on the partition coefficient, heteroatom-containing organic compounds and any aromatic hydrocarbons also, to some extent, reach the second stream obtained from step a), but the second stream is more hydrophobic than the first stream. Thus, the second stream further comprises heteroatom-containing organic compounds and optionally aromatic hydrocarbons in addition to aliphatic hydrocarbons. The first and second streams may further contain conjugated aliphatic compounds having two or more carbon-carbon double bonds.

[0056] In step a), the washing solvent a) may be added separately from and in the liquid hydrocarbon feedstock stream, in addition to any washing solvent a) that may be present in the liquid hydrocarbon feedstock stream, such as water, and may be mixed with the liquid hydrocarbon feedstock stream. In step a), it is preferable that the stream containing the added washing solvent a) does not contain or substantially contains heteroatom-containing organic compounds, and does not contain or substantially contains other contaminants, thereby increasing the efficiency of removing such contaminants from the liquid hydrocarbon feedstock stream.

[0057] In step a) of this process, at least a portion of the liquid hydrocarbon feedstock stream is brought into contact with the washing solvent a). In addition, in step a), the stream may also preferably be brought into contact with the sorbent, which is further described below in relation to the sorption step (i).

[0058] The washing solvent a) in step a) contains one or more heteroatoms, which may be oxygen, nitrogen, and / or sulfur. Preferably, the washing solvent a) is miscible in heptane or has relatively low miscibility. Preferably, the washing solvent a) is miscible in heptane such that, based on the weight of heptane, up to 10% by weight, or up to 3% by weight, or up to 1% by weight, or up to 0.5% by weight, or up to 0.1% by weight of the washing solvent a) can be mixed in the heptane. Furthermore, the miscibility of the washing solvent a) in heptane is preferably lower than the miscibility of the extraction solvent b) in heptane. The miscibility of a particular compound in another compound, such as heptane, can be determined by any common method known to those skilled in the art, including ASTM method D1476. Where the miscibility of one compound in another is referred to herein, this means miscibility at 25°C.

[0059] The washing solvent a) in step a) should be at least 10 MPa 1 / 2 Preferably, at least 20 MPa 1 / 2 , more preferably, at least 30 MPa 1 / 2 More preferably, at least 40 MPa1 / 2 The Hansen solubility parameter distance R for heptane determined at 25°C a、ヘプタン may be possessed. Further, the R for the washing solvent a) a、ヘプタン is at most 55 MPa 1 / 2 more preferably at most 50 MPa 1 / 2 more preferably at most 45 MPa 1 / 2 and may be so. For example, the R for water a、ヘプタン is 45 MPa 1 / 2 The Hansen solubility parameter is further described below in relation to the extraction solvent b) used in step b).

[0060] Furthermore, the washing solvent a) in step a) has a solubility of sodium chloride of at least 0.1 g / 100 g, preferably at least 0.3 g / 100 g, more preferably at least 0.5 g / 100 g, more preferably at least 0.7 g / 100 g, more preferably at least 1 g / 100 g, more preferably at least 2 g / 100 g, more preferably at least 3 g / 100 g, more preferably at least 4 g / 100 g, most preferably at least 5 g / 100 g of sodium chloride per 100 g of the solvent determined at 25°C, and may be at most 50 g / 100 g, or at most 40 g / 100 g, or at most 36 g / 100 g. For example, the solubility of the sodium chloride for water is 36 g / 100 g.

[0061] Still further, the washing solvent a) in step a) is water, ammonia, and the Hansen solubility parameter distance R for diethylammonium acetate (DEAA) determined at 25°C 1 / 2 is at most 15 MPa 1 / 2 preferably at most 13 MPa 1 / 2 more preferably at most 11 MPa a、DEAA and may include one or more solvents selected from the group consisting of organic solvents having the same. Further, the R for the washing solvent a) a、DEAA is at least 5 MPa 1 / 2 preferably at least 8 MPa 1 / 2, more preferably at least 10 MPa 1 / 2 This is possible. For example, the R for monoethylene glycol (MEG) a、DEAA It is 12 MPa 1 / 2 Furthermore, preferably, the organic solvent for the washing solvent a) is R for the same solvent. a、DEAA Larger than R a、ヘプタン It has R a、ヘプタン and R a、DEAA The difference is at least 15 MPa. 1 / 2 , more preferably at least 16 MPa 1 / 2 Most preferably at least 17 MPa 1 / 2 Furthermore, preferably, R a、ヘプタン and R a、DEAA The difference in this regard is up to 25 MPa. 1 / 2 , more preferably up to 22 liters 1 / 2 Most preferably a maximum of 20 MPa 1 / 2 For example, R for monoethylene glycol a、ヘプタン and R a、DEAA The difference is 16.3 MPa. 1 / 2 That is the case.

[0062] As described above, the miscibility of extraction solvent b) and washing solvent a) in heptane is preferably different, and in this case, solvents a) and d) are not the same. Specifically, washing solvent a) is the Hansen solubility parameter distance R for heptane determined at 25°C. a、ヘプタン It may have such R for extraction solvent b). a、ヘプタン Larger than. Preferably, R for solvents a) and b). a、ヘプタン The difference is at least 1 MPa. 1 / 2 , more preferably at least 5 MPa 1 / 2 , more preferably at least 10 MPa 1 / 2 More preferably, at least 15 MPa 1 / 2 , more preferably at least 20 MPa 1 / 2 , more preferably at least 25 MPa 1 / 2 Furthermore, preferably, R for solvents a) and b). a、ヘプタンThe difference in this case is a maximum of 55 MPa. 1 / 2 More preferably, up to 50 MPa 1 / 2 , more preferably up to 45 MPa 1 / 2 , more preferably up to 40 MPa 1 / 2 More preferably up to 35 MPa 1 / 2 More preferably up to 30 MPa 1 / 2 That is the case.

[0063] Specifically, the washing solvent a) in step a) of this process is water, ammonia, and an organic solvent, which includes diols and triols (including monoethylene glycol (MEG), monopropylene glycol (MPG), and glycerol); glycol ethers (oligoethylene glycol including diethylene glycol, triethylene glycol, and tetraethylene glycol, and polyethylene glycol (polyethylene) which may have a molecular weight of 200 to 1,000 g / mol or 200 to 700 g / mol). It may contain one or more organic solvents selected from the group consisting of glycol (including PEG); amides (the alkyl group may contain 1 to 8 or 1 to 3 carbon atoms, including methylformamide); dialkyl sulfoxides (the alkyl group may contain 1 to 8 or 1 to 3 carbon atoms, including dimethyl sulfoxide (DMSO)); sulfones (including sulfolanes); hydroxyesters (including methyl lactate and ethyl lactate, including lactate esters); amine compounds (including ethylenediamine, monoethanolamine, diethanolamine and triethanolamine); carbonate compounds (including propylene carbonate and glycerol carbonate); and cycloalkanone compounds (including dihydrolevoglucocenone). Preferably, the washing solvent a) comprises water and one or more of the above-mentioned diols and triols, specifically monoethylene glycol (MEG) and glycerol, and glycol ethers, specifically diethylene glycol, triethylene glycol, tetraethylene glycol, and polyethylene glycol (PEG) having a molecular weight of 200 to 1,000 g / mol or 200 to 700 g / mol. More preferably, the washing solvent a) comprises water, most preferably water. According to the present invention, the washing solvent a) may also contain one or more solvents not mentioned above in combination with one or more of the above-mentioned solvents, for example water, and the relative amount of the latter solvent can vary over a wide range and may be as low as, for example, 0.1% by weight, based on the total washing solvent.

[0064] In step a), the added washing solvent a), for example, water, may have a pH greater than 7 ("alkaline"), a pH less than 7 ("acidic"), or a pH of about 7 ("neutral").

[0065] Furthermore, in step a), the added washing solvent a), for example, water, may preferably have a pH greater than 7, more preferably greater than 8-14, more preferably 8-14, more preferably 10-14, and most preferably 12-14. Such a flow having such a pH can be provided by adding one or more salts selected from the group consisting of alkali metal carbonates and bicarbonates including sodium bicarbonate, sodium carbonate, lithium carbonate, potassium carbonate, and potassium bicarbonate, as well as alkali metal or alkaline earth metal hydroxides including lithium hydroxide, sodium hydroxide, potassium hydroxide, and calcium hydroxide, and ammonium hydroxide, to the washing solvent a) flow. An alkaline flow containing washing solvent a) having such a pH may be preferred for removing heteroatom-containing organic compounds and / or silicon-containing compounds. Furthermore, the washing performance of such an alkaline flow may be improved by adding sorbents, which are further described below in relation to the sorption step (i), to step a).

[0066] In step a), if an alkaline stream containing a washing solvent a) is supplied to step a), step a) may comprise two or more steps a), where in the first step a), an alkaline stream containing a washing solvent a) having a relatively low pH, for example, 8 to 10, is supplied, and in the second or subsequent step a), an alkaline stream containing a washing solvent a) having a relatively high pH, ​​for example, 10 to 14, is supplied.

[0067] Furthermore, in step a), the added washing solvent a), for example, water, may preferably have a pH of less than 7, more preferably less than 1 to 6, more preferably 1 to 6, more preferably 2 to 5, and most preferably 2 to 4. Such a flow having such a pH can be provided by adding an inorganic acid (mineral acid) or an organic acid to the washing solvent a) flow. Preferably, one or more inorganic acids selected from the group consisting of hydrochloric acid, nitric acid, phosphoric acid, boric acid, perchloric acid, hydrofluoric acid, hydroiodic acid, and sulfuric acid may be added. And / or, preferably, one or more organic acids selected from the group consisting of sulfonic acids, including methanesulfonic acid and p-toluenesulfonic acid, and carboxylic acids, including formic acid, oxalic acid, acetic acid, lactic acid, uric acid, malic acid, tartaric acid, and citric acid may be added. Furthermore, preferably, the acidity of the acid stream can be provided by an ion exchange resin or ion exchange polymer containing an organic polymer such as polystyrene sulfonate or polystyrene crosslinked with divinylbenzene, where the ion exchange sites are introduced after polymerization by functionalization with acid groups, such as sulfonic acid groups or carboxylic acid groups.

[0068] An acid stream containing a washing solvent a) having such a pH may be preferred for removing heteroatom-containing organic compounds and / or metals. Furthermore, the washing performance of such an acid stream can be improved by adding an sorbent, as further described below in relation to the sorbent step (i), to step a). In particular, if an sorbent (e.g., clay) is also added, such an sorbent can be advantageously activated by the acid at the same time, thereby further improving the overall performance. In the case of "in situ" acid activation of such an sorbent, the pH of the stream containing the washing solvent a) is preferably less than 6.5, more preferably 5.4 to 6.5.

[0069] In step a), if an acid stream containing a washing solvent a) is supplied to step a), step a) may comprise two or more steps a), where in the first step a), an acid stream containing a washing solvent a) having a relatively high pH, ​​for example, 4 to 6, is supplied, and in the second or subsequent step a), an acid stream containing a washing solvent a) having a relatively low pH, for example, 2 to 4, is supplied.

[0070] Furthermore, in step a), the flow containing the added washing solvent a), for example, water, may preferably have a pH of about 7. The washing performance of such a neutral flow can be improved by adding an sorbent, which will be further described below in relation to the sorbent step (i), to step a).

[0071] If step a) includes multiple consecutive steps, the stream containing the washing solvent a), e.g., water, supplied to the first step a) preferably has a pH greater than 7, more preferably greater than 8-14, more preferably 8-14, more preferably 10-14, and most preferably 12-14, and the stream containing the washing solvent a), e.g., water, supplied to the second or any other subsequent step a), preferably the last step a) before step b), preferably has a pH of about 7. Such additional neutral washing step a) may also be considered a rinsing step, in which it is preferable not to add an sorbent.

[0072] If step a) includes multiple consecutive steps, the stream containing the washing solvent a), e.g., water, supplied to the first step a) preferably has a pH of less than 7, more preferably less than 1 to 6, more preferably 1 to 6, more preferably 2 to 5, most preferably 2 to 4, and the stream containing the washing solvent a), e.g., water, supplied to the second or any other subsequent step a), preferably the last step a) before step b), preferably has a pH of about 7. Such additional neutral washing step a) may also be considered a rinsing step, in which it is preferable not to add an sorbent.

[0073] The temperature at which step a) is carried out may be in the range of 4 to 400°C, more preferably in the range of 4 to 300°C, and most preferably in the range of 4 to 200°C. Particularly preferably, the temperature is 30 to 200°C, more preferably in the range of 50 to 170°C, and most preferably in the range of 60 to 150°C. The pressure at which step a) is carried out may be in the range of atmospheric pressure to 100 bar, more preferably in the range of atmospheric pressure to 20 bar, and most preferably in the range of atmospheric pressure to 6 bar. Particularly preferably, the pressure is greater than atmospheric pressure to 15 bar, preferably 1.1 to 10 bar, more preferably 1.5 to 8 bar, and most preferably 2 to 6 bar.

[0074] Step a) can be carried out continuously or in batches, preferably continuously. Furthermore, the mixing in step a) can be carried out in any manner known to those skilled in the art. For example, a mixer may be used upstream of a phase separation apparatus as described below. Furthermore, for example, in-line (or static) mixing may be carried out upstream of such a phase separation apparatus. Moreover, the mixing may be carried out in an extraction column as described below.

[0075] Through such addition of the washing solvent a) and mixing in step a), a first phase comprising the washing solvent a), heteroatom-containing compounds, and optionally other contaminants, and a second phase comprising aliphatic hydrocarbons, heteroatom-containing organic compounds, and optionally aromatic hydrocarbons, are obtained from step a), and these phases can be separated into the first and second flows described above, respectively. Therefore, advantageously, the washing solvent a), added separately in step a) from the liquid hydrocarbon feedstock flow, removes some of the heteroatom-containing organic compounds and any other contaminants from the recovered aliphatic hydrocarbons, thereby simultaneously preventing the accumulation of such contaminants downstream of the process and thus improving the overall stability and reliability of the process.

[0076] The phase separation in step a) can be carried out by any apparatus capable of separating the two phases, such as a decanter, flotation device, coalescer, and centrifuge, preferably including a decanter. The phase separation in step a) can be carried out in a single step, for example, in a decanter, flotation device, coalescer, or centrifuge. For example, if a decanter is used in step a), the upper phase, which contains aliphatic hydrocarbons, heteroatom-containing organic compounds, and optionally aromatic hydrocarbons, and the lower phase, which contains washing solvent a), heteroatom-containing compounds, and optionally other contaminants, can be separated into the second stream and the first stream, respectively.

[0077] Furthermore, step a) may be carried out in an extraction column having multiple separation stages. In the latter case, step a) includes contacting at least a portion of a liquid hydrocarbon feed stream with a washing solvent a) in the column and subjecting the feed stream to liquid-liquid extraction with the washing solvent a) to yield a first stream containing the washing solvent a), heteroatom-containing compounds, and optionally other contaminants, and a second stream containing aliphatic hydrocarbons, heteroatom-containing organic compounds, and optionally aromatic hydrocarbons, wherein the washing solvent a) is supplied to the extraction column at a position higher than where the feed stream is supplied, thereby enabling counterflow liquid-liquid extraction, resulting in a top stream (the "second stream") from the extraction column containing aliphatic hydrocarbons, heteroatom-containing organic compounds, and optionally aromatic hydrocarbons, and a bottom stream (the "first stream") from the extraction column containing the washing solvent a), heteroatom-containing compounds, and optionally other contaminants.

[0078] The internal structures within the extraction column contribute to the mixing of the feed material flow and the washing solvent a). Such internal structures of columns are known in the art. The internal structures of the column may include packing materials such as Raschig rings, Paul rings, Lessing rings, Bialecki rings, and Dixon rings; sieve plates; or, in particular, random structure packing materials as described in Perry's Chemical Engineer's Handbook. Furthermore, the column may be provided with stirring means. For example, a shaft may extend along the column, and a rotor and stator fixed to the column may be provided.

[0079] Therefore, advantageously, in step a) prior to step b), all salts and / or silicon-containing compounds and / or metals originating from the liquid hydrocarbon feedstock stream are already removed, and some heteroatom-containing organic compounds are also removed from the aliphatic hydrocarbons recovered from the liquid hydrocarbon feedstock stream, thus reducing the need to separate such heteroatom-containing organic compounds in the subsequent extraction step b). Furthermore, troublesome problems associated with such other contaminants, including salts and / or silicon-containing compounds and / or metals originating from the liquid hydrocarbon feedstock stream (such troublesome problems are discussed in the introduction of this specification), can also be advantageously avoided by already removing such other contaminants in the first step. Thus, not only can the efficiency of the extraction step b) be improved, but at the same time, such troublesome problems caused by such contaminants (heteroatom-containing organic compounds and any other contaminants) can be advantageously prevented, and therefore the stability and reliability of the overall process can be improved.

[0080] At least a portion of the first stream obtained from step a), containing the washing solvent a), the heteroatom-containing compound, and optionally other contaminants, can be recycled back to step a), while another portion can be withdrawn from the process. The heteroatom-containing organic compound removed in step a) can optionally be converted into fuel after a hydrogenation treatment to remove the heteroatoms. Furthermore, the compound removed in step a) can be further separated into various fractions that can be used as solvents.

[0081] If step a) includes a series of steps, in the first step a), at least a portion of the liquid hydrocarbon feed stream may be mixed with the washing solvent a), and the stream containing the added washing solvent a) may have a pH greater than 7 (alkaline) or a pH less than 7 (acidic) as described above, and optionally, after removing all the sorbents as described below in relation to the sorption step (i), the resulting liquid phase may be separated in a decanter, flotation device, coalescer, and centrifuge as described above, preferably in a decanter, into a first stream containing the washing solvent a), heteroatom-containing compounds, and optionally other contaminants, and aliphatic hydrocarbons, heteroatom-containing organic compounds, optionally other contaminants, and optionally a second flow containing aromatic hydrocarbons, in the second step a), at least a portion of the second flow obtained from the first step a) may be brought into contact with washing solvent a), preferably a washing solvent a) stream having a pH of about 7 as described above, in an extraction column such as the one described above, and the second flow may be subjected to liquid-liquid extraction with washing solvent a), resulting in a first flow containing washing solvent a), heteroatom-containing compounds, and optionally other contaminants, and a second flow containing aliphatic hydrocarbons, heteroatom-containing organic compounds, and optionally aromatic hydrocarbons, and at least a portion of the second flow obtained from the second step a) may be supplied to step b). Optionally, the first flow, specifically the first flow obtained from the first step a), may contain any sorbent, as further described below in relation to the sorbent step (i), if the sorbent is not removed before the separation of the first and second flows in the first step a). In the latter case, the adsorbent can be removed from the first flow, for example, by filtration.

[0082] Step b) Extraction with extraction solvent b) In step b) of this process, at least a portion of the second stream obtained from step a) (from which, in the preceding step a), at least a portion of the stream is brought into contact with a washing solvent a) to remove some of the heteroatom-containing organic compounds and any other contaminants, is brought into contact with an extraction solvent b) containing one or more heteroatoms, and the stream is subjected to liquid-liquid extraction with the extraction solvent b) to obtain a first stream containing aliphatic hydrocarbons and optionally heteroatom-containing organic compounds, and a second stream containing the extraction solvent b), heteroatom-containing organic compounds, and optionally aromatic hydrocarbons.

[0083] In step b) of this process, the second flow obtained from step a) may be supplied to a column (extraction column). Furthermore, a solvent flow containing the extraction solvent b) may be supplied to the column at a higher position than the position where the second flow obtained from step a) is supplied, thereby enabling counterflow liquid-liquid extraction and resulting in a top flow from the column (the "first flow" described above) containing aliphatic hydrocarbons and optionally heteroatom-containing organic compounds, and a bottom flow from the column (the "second flow" described above) containing the extraction solvent b), heteroatom-containing organic compounds, and optionally aromatic hydrocarbons.

[0084] In step b), the weight ratio of the extraction solvent b) to the second stream obtained from step a) may be at least 0.05:1, or at least 0.2:1, or at least 0.5:1, or at least 1:1, or at least 2:1, or at least 3:1, and may be at most 5:1, or at most 3:1, or at most 2:1, or at most 1:1. Furthermore, the temperature in step b) may be at least 0°C, or at least 20°C, or at least 30°C, or at least 40°C, or at least 50°C, and may be at most 200°C, or at most 150°C, or at most 100°C, or at most 70°C, or at most 60°C, or at most 50°C, or at most 40°C. The pressure in step b) may be at least 100 mbara, or at least 500 mbara, or at least 1 bara, or at least 1.5 bara, or at least 2 bara, and may be at most 50 bara, or at most 30 bara, or at most 20 bara, or at most 15 bara, or at most 10 bara, or at most 5 bara, or at most 3 bara, or at most 2 bara, or at most 1.5 bara. The temperature and pressure in step b) are preferably such that both the hydrocarbon from the second flow obtained in step a) and the extraction solvent b) are in a liquid state.

[0085] In step b), aliphatic hydrocarbons are recovered by liquid-liquid extraction of heteroatom-containing organic compounds and optionally aromatic hydrocarbons with extraction solvent b). Preferably, the recovered aliphatic hydrocarbons include aliphatic hydrocarbons having a boiling point of 30 to 300°C and aliphatic hydrocarbons having a boiling point of 300 to 600°C in a weight ratio of 99:1 to 1:99. With respect to aliphatic hydrocarbons in the liquid hydrocarbon feed stream, the above description of the weight ratio of aliphatic hydrocarbons having a boiling point of 30 to 300°C and aliphatic hydrocarbons having a boiling point of 300 to 600°C also applies to the recovered aliphatic hydrocarbons.

[0086] In step b), the liquid-liquid extraction yields a first stream containing aliphatic hydrocarbons and optionally heteroatom-containing organic compounds, and a second stream containing the extraction solvent b), heteroatom-containing organic compounds, and optionally aromatic hydrocarbons. For the purposes of this specification, the former stream containing the recovered aliphatic hydrocarbons (first stream) may be referred to as the “raffinate stream,” and the latter stream (second stream) may be referred to as the “extract stream.” Such a raffinate stream has reduced content of aromatic hydrocarbons, conjugated aliphatic compounds having two or more carbon-carbon double bonds, and heteroatom-containing organic compounds. Such a raffinate stream contains no aromatic hydrocarbons, or contains them in amounts of up to 10% by weight, up to 5% by weight, or up to 1% by weight, or substantially no aromatic hydrocarbons. Furthermore, such a raffinate stream contains no conjugated aliphatic compounds having two or more carbon-carbon double bonds, or contains them in amounts of up to 15% by weight, up to 10% by weight, up to 5% by weight, or up to 1% by weight, or substantially no aromatic hydrocarbons. Furthermore, such raffinate streams do not contain heteroatom-containing organic compounds, or contain them at a maximum of 1% by weight, or are substantially free of them.

[0087] The extraction solvent b) used in step b) of this process may be supplied to the column as a solvent stream in step b), and preferably has a density at least 3%, or at least 5%, or at least 8%, or at least 10%, or at least 15%, or at least 20% higher than the density of the second stream obtained from step a). Furthermore, the density may be up to 50%, or up to 40%, or up to 35%, or up to 30% higher than the density of the second stream obtained from step a).

[0088] Furthermore, the extraction solvent b) used in step b) contains one or more heteroatoms, which may be oxygen, nitrogen, and / or sulfur. It is also preferable that the extraction solvent b) is thermally stable at a temperature of 200°C. Furthermore, the extraction solvent b) may have a boiling point of at least 50°C, or at least 80°C, or at least 100°C, or at least 120°C, and at most 300°C, or at most 200°C, or at most 150°C. Furthermore, it is preferable that the extraction solvent b) is miscible in heptane or has relatively low miscibility. Preferably, the extraction solvent b) is miscible in heptane such that, based on the weight of heptane, up to 30% by weight, or up to 20% by weight, or up to 10% by weight, or up to 3% by weight, or up to 1% by weight of the extraction solvent b) is miscible in heptane. The miscibility of a particular compound in another compound, such as heptane, can be determined by any common method known to those skilled in the art, including ASTM method D1476. Where the miscibility of a compound in another compound is referred to herein, this means miscibility at 25°C.

[0089] Furthermore, the extraction solvent b) in step b) should be at least 3 MPa. 1 / 2 Preferably at least 5 MPa 1 / 2 , more preferably at least 10 MPa 1 / 2 More preferably, at least 15 MPa 1 / 2 The Hansen solubility parameter distance R for heptane, determined at 25°C. a、ヘプタン It may have the R of the extraction solvent b). a、ヘプタン 45MPa 1 / 2 Less than or up to 40 MPa 1 / 2 Preferably, up to 35 MPa 1 / 2 More preferably up to 30 MPa 1 / 2 More preferably up to 25 MPa 1 / 2 This is possible. For example, the R for N-methylpyrrolidone (NMP) a、ヘプタン It is 15MPa 1 / 2 That is the case.

[0090] Furthermore, the extraction solvent b) has a Hansen solubility parameter distance R for toluene determined at 25 °C a、トルエン that is at least 1.5 MPa 1 / 2 , preferably at least 2 MPa 1 / 2 greater than the Hansen solubility parameter distance R for heptane a、ヘプタン ; i.e., it may have a difference (i.e., R a、ヘプタン -R a、トルエン ). Further, the difference between R a、トルエン for the extraction solvent b) and R a、ヘプタン may be at most 4.5 MPa 1 / 2 , preferably at most 4 MPa 1 / 2 .

[0091] Hansen solubility parameters (HSP) can be used as a means to predict the likelihood of one component mixing with another. More specifically, each component is characterized by three Hansen parameters, each generally expressed in MPa 0.5 , where δ d represents the energy from intermolecular dispersion forces, δ p represents the energy from intermolecular dipole-dipole forces, and δ h represents the energy from intermolecular hydrogen bonding. The affinity between compounds can be described using the multi-dimensional vector that quantifies the atomic and intermolecular interactions of these solvents as the Hansen solubility parameter (HSP) distance R a defined by Equation (1): (R a ) 2 =4(δ d2 -δ d1 ) 2 +(δ p2 -δ p1 ) 2 +(δ h2 -δ h1 ) 2 (1) In the formula, R a = the distance in HSP space between Compound 1 and Compound 2 (MPa 0.5 ) δd1 , δ p1 , δ h1 = Hansen (or equivalent) parameter of compound 1 (MPa 0.5 ) δ d2 , δ p2 , δ h2 = Hansen (or equivalent) parameter of compound 2 (MPa 0.5 )

[0092] Therefore, for a given solvent calculated with respect to the compound to be recovered (i.e., the compound to be recovered is compound 1 and the solvent is compound 2, or vice versa), the smaller the value of R a , the higher the affinity of this solvent for the compound to be recovered.

[0093] Hansen solubility parameters for many solvents can be found, inter alia, in CRC Handbook of Solubility Parameters and Other Cohesion Parameters, Second Edition by Allan F.M. Barton, CRC press 1991; Hansen Solubility Parameters: A User’s Handbook by Charles M. Hansen, CRC press 2007.

[0094] Specifically, the extraction solvent b) used in step b) of this process is ammonia, or preferably diols and triols (including any isomers of monoethylene glycol (MEG), monopropylene glycol (MPG), butanediol, and glycerol); glycol ethers (including diethylene glycol, triethylene glycol, and tetraethylene glycol, including oligoethylene glycol), and their monoalkyl ethers (including diethylene glycol ethyl ether); amides (including N-alkylpyrrolidone, where the alkyl group may contain 1 to 8 or 1 to 3 carbon atoms, including N-methylpyrrolidone (NMP)); formamides, and di and monoalkylformamides, and acetamides (where the alkyl group may contain 1 to 8 or 1 to 3 carbon atoms, including dimethylformamide (DMF), methylformamide, and dimethylacetamide); dialkyl sulfoxides (where the alkyl group contains 1 to 8 or 1 to 3 carbon atoms) It may contain one or more organic solvents selected from the group consisting of: dimethyl sulfoxide (DMSO); sulfones (sulfolane); N-formylmorpholine (NFM); furan ring-containing components and their derivatives (including furfural, 2-methylfuran, furfuryl alcohol, and tetrahydrofurfuryl alcohol); hydroxyesters (including methyl lactate and ethyl lactate, and lactic acid esters); trialkyl phosphates (including triethyl phosphate); phenol compounds (including phenol and guaiacol); benzyl alcohol compounds (including benzyl alcohol); amine compounds (including ethylenediamine, monoethanolamine, diethanolamine, and triethanolamine); nitrile compounds (including acetonitrile and propionitrile); trioxane compounds (including 1,3,5-trioxane); carbonate compounds (including propylene carbonate and glycerol carbonate); and cycloalkanone compounds (including dihydrolevoglucocenone).

[0095] More preferably, the extraction solvent b) comprises one or more of the above-mentioned dialkyl sulfoxides, specifically DMSO; sulfones, specifically sulfolanes; N-alkylpyrrolidones, specifically NMP; and furan ring-containing components, specifically furfural. Even more preferably, the extraction solvent b) comprises one or more of the above-mentioned N-alkylpyrrolidones, specifically NMP, and furan ring-containing components, specifically furfural. Most preferably, the extraction solvent b) comprises NMP.

[0096] Aqueous solutions of quaternary ammonium salts, specifically trioctylmethylammonium chloride or methyltributylammonium chloride, may also be used as the extraction solvent b) in step b).

[0097] As described above, the second stream obtained from step b) (this stream for the first (extraction) column above corresponds to the bottom stream from such a column) comprises the extraction solvent b), a heteroatom-containing organic compound, and optionally an aromatic hydrocarbon. The stream may further contain conjugated aliphatic compounds having two or more carbon-carbon double bonds, if such compounds are present in the second stream obtained from step a).

[0098] In the present invention, the extraction solvent b) may be recovered from a second stream obtained from step b) and optionally from a first stream obtained from step b) (if the latter stream also contains the extraction solvent b)), and then, advantageously, recycled back to step b). Preferably, the extraction solvent may be recovered and recycled in any manner, for example, as described in International Publication No. 2020 / 212315 or concurrently pending European Patent Application No. 2020 / 2249.7 filed on 16 October 2020 (these disclosures are incorporated herein by reference).

[0099] Advantageously, any aromatic hydrocarbons, and conjugated aliphatic compounds having two or more carbon-carbon double bonds, removed when the extraction solvent is recovered as described above, can be blended with pygas and processed into fuel or used to produce aromatic compounds. Similarly, heteroatom-containing organic compounds removed during such recovery can also be converted into fuel after optionally undergoing hydrogenation to remove heteroatoms. Furthermore, such compounds removed during recovery can be further separated into various fractions that can be used as solvents.

[0100] Acquisition steps (i), (ii), (iii) and (iv) In the present invention, advantageously, an sorbent is used in steps (i), (ii), (iii), and (iv) to remove heteroatom-containing organic compounds and optionally aromatic hydrocarbons, and optionally other contaminants such as the silicon-containing compounds and metals, which are present in the liquid hydrocarbon feed stream or do not need to be completely removed in extraction step b), but are entrained in the first stream obtained from step a), which contains the recovered aliphatic hydrocarbons, for example, because the concentration of these contaminants in the liquid hydrocarbon feed stream is relatively high. By such sorbent, advantageously, a final purified hydrocarbon product of sufficiently high quality can be obtained, as a result, which can be further processed and, for example, supplied to a steam cracking unit.

[0101] The removal of heteroatom-containing organic compounds, optionally aromatic hydrocarbons, and optionally other contaminants by the above sorption is carried out in the following steps in this process: (i) step a) bringing at least a portion of the liquid hydrocarbon feed stream into contact with the sorbent before the first and second flows are separated in step a), and / or (ii) Between the preceding step a) and the subsequent step a), a step of bringing at least a portion of the second flow obtained from the preceding step a) into contact with the sorbent, and / or (iii) Between step a) and b), a step of bringing at least a portion of the second flow obtained from step a) into contact with the sorbent, and / or (iv) After step a), one or more of the steps of contacting at least a portion of the first stream obtained from step b) containing aliphatic hydrocarbons and heteroatom-containing organic compounds with an sorbent.

[0102] Therefore, specifically, the sorption described above may be applied in this process in one or more of the following steps (i), (ii), (iii), and (iv), which correspond to steps (i), (ii), (iii), and (iv) above. (i) A portion of the heteroatom-containing organic compound is removed from the liquid hydrocarbon feedstock flow by contacting at least a portion of the flow with the sorbent in step a), before the first and second flows are separated in step a), and at least a portion of the treated flow obtained from step (i) is supplied to step b), and / or (ii) step a) comprises a series of steps a), wherein a portion of the heteroatom-containing organic compound is removed from a second flow obtained from a preceding step a) by contacting at least a portion of the flow with an sorbent, and at least a portion of the treated flow obtained from step (ii) is supplied to a subsequent step a), and / or (iii) A portion of the heteroatom-containing organic compound is removed from the second flow obtained from step a) by contacting at least a portion of the flow with the sorbent, and at least a portion of the treated flow obtained from step (iii) is supplied to step b), and / or (iv) The first stream obtained from step b) contains an aliphatic hydrocarbon and a heteroatom-containing organic compound, and the heteroatom-containing organic compound is removed from the stream by bringing at least a portion of the stream into contact with the sorbent.

[0103] Preferably, the sorbation described above is applied in one or more of steps (i), (iii), and (iv) in this process. Furthermore, if the sorbation step (iii) is applied and the washing step a) includes a series of consecutive steps a), at least a portion of the second flow obtained from the last of the consecutive steps a) may be brought into contact with the sorbent.

[0104] If the process includes one sorption step, such single sorption step is preferably sorption step (iii) or (iv), most preferably sorption step (iv). If the process includes two sorption steps, these are preferably sorption steps (i) and (iii), or sorption steps (i) and (iv), most preferably sorption steps (i) and (iv).

[0105] The sorbation steps (i), (ii), (iii), and (iv) will, advantageously, concentrate at least a portion of the contaminants in the sorbent used in such sorbation steps, in addition to their removal by the extraction step b) of the process, thereby enabling the delivery of a final hydrocarbon product of sufficiently high quality (purity). The sorbation steps (i), (ii), (iii), and (iv) will allow the process to further treat liquid hydrocarbon feed streams containing relatively large amounts of heteroatom-containing organic contaminants and optionally other contaminants. In addition, the accumulation of these contaminants in the recirculated stream of any extraction solvent b) to step b) will, advantageously, not result in the accumulation of these contaminants in the final hydrocarbon product through the sorbation step (iv) of the process. Furthermore, through the sorbition steps (i), (ii) and (iii) in this process, the accumulation of these contaminants in the recirculated extracting solvent b) into step b) can be prevented, as the subsequent steps of these contaminants are already removed from the feed material stream before being subjected to the extraction step b). Thus, the sorbent retains the contaminants, and this sorbent can eventually be regenerated or removed from the process and replaced with a new sorbent, thereby continuing to provide the above-mentioned advantages.

[0106] Furthermore, in the present invention, a portion of the treated flow obtained from the sorbing steps (i), (ii), and (iii) of the process may be supplied to the extraction step b), while another portion may bypass step b). It is also conceivable that the entire treated flow obtained from steps (i), (ii), and (iii) may bypass step b), but this is not part of the claimed invention. For example, such a bypass may be preferable if the quality of the treated flow is already sufficiently high to meet the specifications for the vapor cracker feedstock. Then, at least a portion of the treated flow may preferably be supplied directly to the vapor cracker without an intermediate extraction step.

[0107] Advantageously, flexibility is added to the process so that a wide range of liquid hydrocarbon feedstocks having different qualities (different contaminants and / or different levels of contaminants) can be processed through the option of sorbing steps (i), (ii), (iii) and / or (iv) combined with washing step a), and the option of (partial) bypassing extraction step b) as described above.

[0108] In the sorbent steps (i), (ii), (iii), and (iv) described above, contact with the sorbent can be carried out in any manner known to those skilled in the art.

[0109] In the sorbing step (i), the sorbent is preferably present in step a) as a suspension containing sorbent particles. Such sorbent particles may be added to the stream containing the washing solvent a) which is added in step a). In the case of such a suspension, the sorbent is preferably removed from the treated stream, for example by filtration, before the first and second streams are separated in step a). Alternatively, the sorbent may be removed together with the first stream containing the washing solvent a) and the heteroatom-containing compound by sedimentation or by applying a different method, for example by using a separator such as a centrifuge or liquid cyclone when separating the first and second streams in step a).

[0110] Furthermore, in sorbation steps (ii), (iii), and (iv), the sorbent may exist as a suspension containing sorbent particles, as described above for sorbation step (i), or it may be fixed to the filling bed. Preferably, in sorbation steps (ii), (iii), and (iv), the sorbent is fixed to the filling bed.

[0111] In the present invention, the relative amount of the sorbent in the sorbing steps (i), (ii), (iii), and (iv) may be 0.01% to 20% by weight, preferably 0.1% to 5% by weight, and more preferably 0.1% to 1% by weight, based on the feed to be processed in the sorbing step when the above-described suspension is used. Furthermore, when the above-described packed bed is used in the sorbing steps (ii), (iii), and (iv), the liquid hourly space velocity (LHSV) may be 0.1 to 50 l / hour, preferably 1 to 10 l / hour. The specific target LHSV may depend on several factors, such as temperature and the concentration of contaminants.

[0112] In this specification, sorption means the process by which one substance (sorbent) incorporates or retains another substance by absorption, adsorption, or a combination of both. Preferably, the sorbent used in the present invention is an sorbent that preferentially sorbs the heteroatom-containing compounds, optionally aromatic hydrocarbons, and optionally other contaminants. Specifically, it is preferable that the heteroatom-containing compounds, optionally aromatic hydrocarbons, and optionally other contaminants are preferentially sorbed compared to the recovered aliphatic hydrocarbons and compared to any extraction solvent and / or washing solvent as defined herein.

[0113] The adsorbent used in steps (i), (ii), (iii), and (iv) of this process preferably has a porous structure composed of micropores, mesopores, macropores, or a combination thereof. According to IUPAC notation, a microporous structure has a pore diameter of less than 2 nm (20 Å, angstroms), a mesoporous structure has a pore diameter of 2 to 50 nm (20 to 500 Å), and a macroporous structure has a pore diameter of more than 50 nm (500 Å).

[0114] The adsorbents that can be suitably used in steps (i), (ii), (iii), and (iv) are not limited to the specific materials listed herein. In general, any material of any form having a treated or untreated surface, of natural or synthetic, inorganic or organic origin, characterized by having a porous structure including a relatively high specific surface area, micropores, mesopores, or macropores, or a combination thereof, can be used in the present invention. The specific surface area is 1 to 3000 m². 2 / g, preferably 50-2000m 2 / g, comfortable 100~1000m 2 The range may be / g. The specific surface area is at least 1m². 2 / g or at least 10m 2 / g or at least 50mg 2 / g may also be acceptable. Furthermore, up to 3000m 2 / g or up to 1000m 2 / g or up to 500m 2 It may also be / g. Furthermore, an adsorbent suitable for use in steps (i), (ii), (iii) and (iv) is at least 0.001 cm 3 / g, or at least 0.01cm 3 / g, or at least 0.1cm 3 / g, and a maximum of 1cm 3 / g, or up to 3cm 3 / g, or up to 5cm 3 / g, or up to 10cm 3 It has a pore volume of / g. A suitable sorbent for use in steps (i), (ii), (iii), and (iv) may satisfy two of the above properties, namely pore diameter and surface area, or pore diameter and pore volume, or surface area and pore volume.

[0115] The adsorbents that can be conveniently used in steps (i), (ii), (iii), and (iv) of the process of the present invention may be synthetic or natural molecular sieves. Furthermore, the adsorbents that can be conveniently used in steps (i), (ii), (iii), and (iv) of the process of the present invention may be inorganic molecular sieves, such as metal oxides (where the metal is one or more of alkaline earth metals such as Al, Si, Zn, Mg, Ti, Zr, transition metals, and post-transition metals), or zeolites, clays, activated clays, alumina, activated alumina, amorphous alumina, silica gel, diatomaceous earth, magnesium silicate, aluminum silicate, amorphous silica, porous glass, etc., or organic molecular sieves, such as activated carbon, crosslinked and porous polymers, carbonaceous materials, such as carbon char (where "char" means "wood charcoal"), graphene-based nanomaterials, and single-walled or multi-walled carbon nanotubes, or hybrid molecular sieves such as metal-organic skeletons. The adsorbent may be dispersed in a porous amorphous inorganic or organic matrix (also referred to as a binder material) having channels and cavities therein that allow liquid access to the adsorbent. Alternatively, the adsorbent may be used without a binder material.

[0116] The adsorbent used in steps (i), (ii), (iii), and (iv) of this process may be one or more adsorbents selected from the group consisting of bleached clay, hydrogel silica, silicates, and activated carbon. Bleached clay is particularly preferred.

[0117] Bleached clay minerals are hydrated phyllosilicates that may contain varying amounts of aluminum, iron, magnesium, alkali metals, alkaline earth elements, and other cations. Phyllosilicates may include the following mineral subgroups: serpentine, clay minerals, mica, and chlorites.

[0118] Preferably, adsorbents suitable for the present invention are phyllosilicates from the serpentine-kaolin group, talc-pyrophyllite group, smectite group, vermiculite or illite group, and / or mica group. Phyllosilicates from the serpentine group may include antigorite, chrysotile, and lizardite. Phyllosilicates from the kaolin group may include halloysite, kaolinite, illite, montmorillonite, vermiculite, talc, sepiolite, palygorskite (or attapulgite), and pyrophyllite. Phyllosilicates from the mica group may include biotite, fuchsite, muscovite, phlogopite, lepidolite, margalite, and erythrolite. Phyllosilicates from the chlorite group may include chlorite.

[0119] More preferably, suitable adsorbents for the present invention include highly active clays from the smectite group such as bentonite or sepiolite, which may mainly contain montmorillonite (these clays can be applied after acid activation); naturally active clays, also known as Fuller's earth; and surface-modifying adsorbents that can be activated "in situ" by the addition of acid, such as formite, attapulgite (or palygorskite) and meerschmitt. These clays may also contain several other minerals such as calcium carbonate, quartz, and feldspar. Suitable examples of commercially available bleached clays are the Grade F series and Nevergreen from BASF, the Pure-Flo series and Perform series from Oil-Dri Corp, the CynerSorb series from Imerys, and the Tonsil series from Clariant.

[0120] Other materials that can be used as suitable adsorbents in steps (i), (ii), (iii), and (iv) of the present invention are hydrated layered alkali silicates. They may be natural or synthetic and contain SiO2 layers (sheets) having a negative charge, alkaline cations for charge compensation, and optionally interlayer water. Examples of hydrated layered silicates are kanemite, octosilicate, magadiite, and kenyaite. Furthermore, hydrated layered alkali silicates can be functionalized to obtain inorganic-organic hybrids for sorption purposes. Due to their high cation exchange capacity, hydrated layered alkali silicates are preferably used for the removal of metal ions. Ion exchange resins also have the ability to replace mineral acids when used as catalysts, as well as the ability to remove contaminants such as metals and heteroatom-containing compounds including phenols, aldehydes, and organic acids. For example, ion exchange resins have been used to remove fatty acids from oils. Commercially available ion exchange resins include those from Dow-Dupont's Amberlite® series, such as Amberlyst A23 (for acid removal), Amberlite XAD4 (for phenol removal), and the Amberlyst series (as a substitute for mineral acids in reactions). Such ion exchange resins can also be suitably used as sorbents in the present invention.

[0121] Clay or layered silicate adsorbents suitable for use in steps (i), (ii), (iii), and (iv) of the present invention can be characterized by their pore volume, surface area, ion exchange capacity (IEC), and pore size distribution. Clay or layered silicates suitable for the present invention have at least 0.1 cm 3 / g, more preferably 0.4cm 3 More than / g, most preferably 0.5cm 3 It has a pore volume greater than / g. The specific pore volume is preferably up to 1.0 cm³. 3 / g, more preferably a maximum of 0.8cm 3 / g, most preferably a maximum of 0.7cm 3 The value is / g. A suitable clay or layered silicate for the present invention is preferably 100m 2 / g~500m2 / g, more comfortably 200m 2 / g~400m 2 It has a surface area in the range of / g. Layered silicates suitable for the present invention have an ion exchange capacity (IEC) of at least 25 meq / 100g, preferably greater than 40 meq / 100g, and most preferably in the range of 50 meq / 100g to 80 meq / 100g. Synthetic layered silicates may have an ion exchange capacity of up to 500 meq / 100g. Clays or layered silicates suitable for the present invention are characterized by having a pore size distribution such as at least 20%, more preferably at least 22%, and most preferably at least 30% of the total pore volume, and provided by pores having a maximum diameter of 7.5 nm. Preferably, at least 40%, more preferably at least 45%, and most preferably at least 50% of the total pore volume are provided by pores having a maximum diameter of 14 nm. Preferably, less than 40%, more preferably less than 35%, of the total pore volume are provided by pores having a diameter greater than 25 nm.

[0122] Furthermore, the adsorbents used in steps (i), (ii), (iii), and (iv) of the present invention may be combinations of adsorbents disclosed herein. An example of a clay combination is an attapulgite / montmorillonite mixture preferably containing 10 to 90% by weight of attapulgite, more preferably 20 to 60% by weight of attapulgite, and most preferably 30 to 50% by weight of attapulgite.

[0123] In order to optimally remove contaminants in steps (i), (ii), (iii), and (iv), the inorganic adsorbent may first need to be subjected to thermal or chemical treatment or activation, as is known to those skilled in the art.

[0124] Suitable carbon-containing adsorbents for use in steps (i), (ii), (iii), and (iv) of the present invention may consist mainly of carbon, for example, a substance containing 80-100% by weight of carbon, preferably 90-100% by weight of carbon, more preferably 95-100% by weight of carbon, most preferably 98-100% by weight of carbon, and very preferably 99-100% by weight of carbon.

[0125] In steps (i), (ii), (iii), and (iv), the preferred activated carbon as an adsorbent for removing one or more of the above contaminants, including heteroatom-containing organic compounds, is from a bituminous source. Furthermore, activated carbon that can be used as such an adsorbent is preferably characterized by having an iodine value in the range of 500 to 1200 mg / g and a high molasses value in the range of 95 to 1500, preferably 200 to 1500. "Iodine value" is a relative measure of pores with a size of 10 to 28 angstroms. It is reported as milligrams of elemental iodine adsorbed per gram of granular activated carbon and determines the area available on the activated carbon for adsorbing low molecular weight organic compounds. The iodine value can be determined according to ASTM D4607. "Molasses value" measures the extent to which the activated carbon removes color from the stock solution. It measures pores greater than 28 angstroms. These are the pores involved in the removal of organic compounds with larger molecular weights. In this case, the amount of molasses that has been sorbed is quantified.

[0126] Furthermore, a suitable activated carbon for the present invention is 600-2000 m 2 It has a total specific surface area in the range of / g and a total pore volume in the range of 0.9 to 2.5 ml / g. Furthermore, a preferred activated carbon for the present invention has pores larger than 20 angstroms, with a total pore volume of 100 m 2 It has a specific surface area greater than / g and a pore volume greater than 0.5 ml / g. These properties are advantageous when removing relatively large molecules, including the heteroatom-containing organic compound and optionally selected aromatic hydrocarbons, which are removed in steps (i), (ii), (iii), and (iv).

[0127] Surface-modified and / or functionalized activated carbon and carbon char can also be suitably used in steps (i), (ii), (iii), and (iv). Suitable methods for generating functional properties on the carbon material surface include oxidation with liquid and gaseous oxidizing agents, grafting of functional groups onto the material surface, physicoadsorption of ligands, vapor deposition, and / or functional groups generated during the carbon activation process.

[0128] Suitable adsorbents for steps (ii), (iii), and (iv) of the present invention may be molecular sieves that are zeolite-based, silica gel, alumina, clay-based, or activated carbon.

[0129] In the present invention, the subgroup of heteroatom-containing organic compounds removed in the sorption steps (ii), (iii), and (iv) may include organic chlorides that may be polar or nonpolar. Adsorbents containing zeolites are suitable for removing such organic chlorides. Specifically, adsorbents containing zeolites with a faujasite (FAU) skeleton such as X and Y, dealumininated zeolite Y, low sodium ultrastable Y (USY); MFI types such as ZSM-5 and pentasyl zeolite; MWW types such as MCM-22, ITQ-1, and SSZ-25; BEA types such as zeolite beta; and mordenite (MOR) types are particularly suitable as adsorbents in the present invention for removing organic chlorides. Furthermore, the zeolite component of the adsorbent may be impregnated with metal cations derived from alkali metals, alkaline earth metals, transition metals, or post-transition metals as defined in the periodic table of elements. Since organic chlorides can release chlorides in the form of hydrochloric acid after interacting with zeolite-based adsorbents, the adsorbent may also need to include basic or amphoteric oxides such as alkali metal or alkaline earth metal oxides, hydroxides or carbonates, or activated alumina or another metal oxide that can capture the released hydrochloric acid. Examples of commercially available zeolite-based materials suitable for the present invention are the adsorbent PCL-100 from UOP, CL-850 from BASF, and TCR-16 from UniCat.

[0130] Furthermore, in the present invention, another subgroup of heteroatom-containing organic compounds removed in sorption steps (ii), (iii), and (iv) may include polar components. Adsorbents containing silica gel are suitable for removing such polar components. A suitable example of commercially available silica gel for removing polar components is TRISYL® from Grace Materials Technologies. Furthermore, suitable adsorbents for preferential sorption of polar components including the above-mentioned organic chlorides include zeolite materials having polarity determined by their Si / Al ratio, or zeolites that have been treated, such as cation exchange or surface modification, to increase their affinity for heteroatom-containing compounds and preferentially polar compounds.

[0131] In the present invention, contaminants that may need to be removed by the adsorbent may be silica and the silicon-containing compounds mentioned above, such as siloxane compounds. Preferably, silica gel, zeolite 13X, activated alumina, hydrotalcite (general formula Mg6Al2CO3(OH) 16 Solubilizers containing layered double hydroxide clay (4(H2O)) and activated carbon may be suitable for removing such silicon-containing compounds.

[0132] The temperature in steps (ii), (iii), and (iv) may be in the range of ambient temperature ~400°C, preferably 40~200°C, more preferably 40~180°C. Furthermore, the pressure in steps (ii), (iii), and (iv) may be in the range of ambient pressure ~100 bar, preferably 5~30 bar, most preferably 5~20 bar. This pressure may be different from the pressure in washing step a) (this step a) may include sorption step (i)) and the pressure in extraction step b).

[0133] Heteroatom-containing compounds and optionally aromatic hydrocarbons accumulate in the adsorbent material, generating "spent adsorbent." As is known in the art, eventually the adsorbent needs to be replaced or regenerated. In either case, the corresponding container containing the spent adsorbent is decommissioned. In the case of regeneration, the spent adsorbent is brought into contact with a flow that does not contain heteroatom-containing compounds and optionally aromatic hydrocarbons. Preferably, this flow is heated to promote the desorption of heteroatom-containing compounds and optionally aromatic hydrocarbons. The regeneration flow can be a gas, liquid, or supercritical fluid. It can be inert, such as nitrogen, or reactive, such as hydrogen, oxygen, and hydrogen peroxide. Depending on the regeneration method, the regeneration temperature is in the range of 20 to 350°C. Regeneration of the adsorbent material can be carried out by stripping it with a flow such as steam or nitrogen, or by heating the adsorbent in air to burn the adsorbed material. Alternatively, if the adsorbent material used in the present invention cannot be completely regenerated, it must be discarded when its adsorption capacity is reached. Furthermore, with respect to the adsorbent used in step a), if the adsorbent is separated as spent adsorbent, the organic compounds contained in the adsorbent can be removed by washing the adsorbent with an organic solvent known in the art. Alternatively, the adsorbent can be removed for disposal such as incineration.

[0134] Upstream and downstream integration In the present invention, the liquid hydrocarbon feed stream may contain at least a portion of the hydrocarbon products formed in a process including the decomposition of plastics, preferably waste plastics, more preferably mixed waste plastics, wherein at least a portion of the plastics contains heteroatom-containing organic compounds.

[0135] Therefore, the present invention also relates to a process for recovering aliphatic hydrocarbons from plastics, wherein at least a portion of the plastics contains a heteroatom-containing organic compound, and the process is (I) A step of decomposing the plastic and recovering hydrocarbon products including aliphatic hydrocarbons, heteroatom-containing organic compounds, and optionally aromatic hydrocarbons, (II) The step of subjecting a liquid hydrocarbon feed stream containing at least a portion of the hydrocarbon product obtained in step (I) to the above process for recovering aliphatic hydrocarbons from the liquid hydrocarbon feed stream.

[0136] The preferences and embodiments described above as such in relation to this aliphatic hydrocarbon recovery process also apply to step (II) of the process for recovering aliphatic hydrocarbons from plastics. In step (I) above, the hydrocarbon product obtained may be a liquid, a solid, or a wax. In the latter case, the solid or wax is first heated to a liquid before being subjected to the aliphatic hydrocarbon recovery process of step (II).

[0137] In the process described above, at least a portion of the plastic supplied to step (I) contains a heteroatom-containing organic compound, which is preferably waste plastic, more preferably mixed waste plastic. In step (I), the decomposition of the plastic may involve a thermal decomposition process and / or a catalytic decomposition process. The decomposition temperature in step (I) may be 300-800°C, preferably 400-800°C, more preferably 400-700°C, and even more preferably 500-600°C. Furthermore, any pressure may be applied, which may be below atmospheric pressure, at atmospheric pressure, or above atmospheric pressure. The heat treatment in step (I) causes the plastic to melt and its molecules to decompose into smaller molecules. The decomposition in step (I) can be carried out as thermal decomposition or as liquefaction. In both thermal decomposition and liquefaction, a continuous liquid phase is formed. In addition, in thermal decomposition, a discontinuous gas phase is formed, which escapes the liquid phase and separates into a continuous gas phase. In liquefaction, no significant gas phase exists due to the application of relatively high pressure.

[0138] Furthermore, in step (I), subsequent condensation of the gas phase and / or cooling of the liquid phase provides a hydrocarbon product which may be liquid, solid, or wax, comprising aliphatic hydrocarbons, heteroatom-containing organic compounds, and optionally aromatic hydrocarbons, at least a portion thereof being subjected to the aliphatic hydrocarbon recovery process in step (II).

[0139] Step (I) above may be carried out in any known manner, for example, in the manner disclosed in International Publication No. 2018 / 069794 or No. 2017 / 168165 (these disclosures are incorporated herein by reference).

[0140] Advantageously, aliphatic hydrocarbons recovered in one of the above processes for the recovery of aliphatic hydrocarbons, which may contain varying amounts of aliphatic hydrocarbons within a broad boiling point range, may be supplied to a vapor cracker without further pretreatment such as hydrogen treatment (hydrotreating or hydroprocessing). In addition to being used as a feedstock for a vapor cracker, the recovered aliphatic hydrocarbons may also be supplied to other purification processes, including hydrocracking, isomerization, hydrotreatment, thermal catalytic cracking, and fluid catalytic cracking. Furthermore, in addition to being used as a feedstock for a vapor cracker, the recovered aliphatic hydrocarbons may also be advantageously separated into different fractions, each of which may find different applications such as diesel, marine fuel, and solvents.

[0141] Accordingly, the present invention also relates to a process for vapor cracking a hydrocarbon feedstock, wherein the hydrocarbon feedstock comprises aliphatic hydrocarbons recovered in one of the above processes for the recovery of aliphatic hydrocarbons. Furthermore, the present invention also relates to a process for vapor cracking a hydrocarbon feedstock, comprising the steps of recovering aliphatic hydrocarbons from a liquid hydrocarbon feedstock stream in one of the above processes for the recovery of aliphatic hydrocarbons, and vapor cracking a hydrocarbon feedstock, wherein the hydrocarbon feedstock comprises aliphatic hydrocarbons recovered in the preceding step. In this specification, the phrase "vapor cracking a hydrocarbon feedstock comprising aliphatic hydrocarbons recovered in the preceding step" may mean "vapor cracking a hydrocarbon feedstock comprising at least a portion of the recovered aliphatic hydrocarbons." The hydrocarbon feedstock to the vapor cracking process may also comprise hydrocarbons from another source other than the present process for the recovery of aliphatic hydrocarbons. Such other sources may be naphtha, hydrowax, or a combination thereof.

[0142] Advantageously, if the liquid hydrocarbon feedstock stream contains aromatic hydrocarbons, particularly polycyclic aromatics, heteroatom-containing organic compounds, conjugated aliphatic compounds having two or more carbon-carbon double bonds, or combinations thereof, these are already removed by the aliphatic hydrocarbon recovery process described above before the recovered hydrocarbons are fed into the vapor cracking process. This is particularly advantageous in that such removed compounds, especially polycyclic aromatics, can no longer cause fouling in the preheating, convection, and radiation sections of the vapor cracker, as well as in heat exchange and / or separation equipment downstream of the vapor cracker, for example, in transfer line exchangers (TLEs) used to rapidly cool effluents from the vapor cracker. When hydrocarbons condense, they can thermally decompose into a coke layer, which can cause fouling. Such fouling is a major factor determining the run-length of the cracker. Reducing the amount of fouling allows for longer run-time without shutting down maintenance and improves heat transfer in the exchangers.

[0143] Vapor decomposition can be carried out in any known manner. The hydrocarbon feed is typically preheated. The feed can be heated using any other combination of heat exchangers, furnaces, or heat transfer and / or heating devices. The feed is vapor-decomposed in a decomposition zone under decomposition conditions to produce at least olefins (including ethylene) and hydrogen. The decomposition zone may comprise any decomposition system known in the art that is suitable for decomposing the feed. The decomposition zone may comprise one or more furnaces, each dedicated to a specific feed or fraction of the feed.

[0144] Decomposition is carried out at high temperatures, preferably in the range of 650–1000°C, more preferably 700–900°C, and most preferably 750–850°C. Steam is usually added to the decomposition zone and acts as a diluent to reduce the hydrocarbon partial pressure, thereby increasing the yield of olefins. Steam also reduces the formation and accumulation of carbonaceous material or coke in the decomposition zone. Decomposition occurs in the absence of oxygen. Residence times under decomposition conditions are very short, typically only a few milliseconds.

[0145] The decomposition unit yields a decomposition unit effluent that may contain aromatic compounds (produced in the vapor decomposition process), olefins, hydrogen, water, carbon dioxide, and other hydrocarbon compounds. The specific products obtained depend on the feed composition, hydrocarbon-to-vapor ratio, and the decomposition temperature and furnace residence time. The decomposed products from the vapor decomposition unit then pass through one or more heat exchangers, often referred to as TLEs ("transfer line exchangers"), to rapidly reduce the temperature of the decomposition products. The TLEs preferably cool the decomposition products to a temperature in the range of 400–550°C.

[0146] figure The process for recovering aliphatic hydrocarbons from a liquid hydrocarbon feed stream is further illustrated in Figures 1 and 2.

[0147] In the process shown in Figure 1, a liquid hydrocarbon feed stream 1 containing aliphatic hydrocarbons (hereinafter referred to as "dienes," including conjugated aliphatic compounds having two or more carbon-carbon double bonds), aromatic hydrocarbons, heteroatom-containing organic compounds, and salts, and a stream 10 containing water, which is the washing solvent a) according to the present invention, and having a pH of approximately 7 (alkaline), are supplied to a mixer 11 and mixed therein. Furthermore, as indicated by "(X)" in Figure 1, an sorbent may be supplied to the mixer 11 representing the sorbing step (i) according to the present invention.

[0148] The resulting mixed flow 12 is supplied to a decanter 20. In the decanter 20, the mixed flow is separated into a flow 21 containing aliphatic hydrocarbons, dienes, aromatic hydrocarbons, and heteroatom-containing organic compounds, and a flow 22 containing water, heteroatom-containing compounds, and salts. Flow 22 is divided into flows 22a and 22b, and flow 22b is recirculated to a mixer 11 after optionally removing organic compounds and salts from flow 22b. Flow 21 and a flow 23 containing water, which is the washing solvent a) according to the present invention, and having a pH of about 7 are supplied to the extraction column 24. Furthermore, as shown in "(X)" in Figure 1, flow 21 may be brought into contact with an sorbent, which represents the sorbent step (ii) according to the present invention. In column 24, flow 21 comes into contact with flow 23 (water), resulting in a liquid-liquid extraction of heteroatom-containing organic compounds with water, yielding a top flow 25 containing aliphatic hydrocarbons, dienes, aromatic hydrocarbons, and heteroatom-containing organic compounds, and a bottom flow 26 containing water and heteroatom-containing compounds. Flow 26 can be combined with a portion of flow 22 from decanter 20. Furthermore, as shown by "(X)" in Figure 1, flow 25 may be brought into contact with an sorbent, which represents sorbent step (iii) according to the present invention.

[0149] Furthermore, in the process shown in Figure 1, a flow 25 from the extraction column 24, a first solvent flow 2 containing an organic solvent (e.g., N-methylpyrrolidone), which is the extraction solvent b) according to the present invention, and a second solvent flow 3 containing water, which is the washing solvent, are supplied to the extraction column 4. In column 4, the flow 25 is brought into contact with the first solvent flow 2 (organic solvent), thereby recovering aliphatic hydrocarbons by liquid-liquid extraction of the diene, aromatic hydrocarbons, and heteroatom-containing organic compounds with the organic solvent. Furthermore, the water in the second solvent flow 3 removes the organic solvent from the top of column 4 by liquid-liquid extraction of the organic solvent with water. The flow 5 containing the recovered aliphatic hydrocarbons exits the top of column 4. Furthermore, a flow 6 containing the organic solvent, water, diene, aromatic hydrocarbons, and heteroatom-containing organic compounds exits the bottom of column 4. As shown by "(X)" in Figure 1, the flow 5 may be brought into contact with an sorbent, which represents the sorption step (iv) according to the present invention. Flow 6 and flow 14, which contains additional water as a demixing solvent, are combined, and the combined flow is supplied to decanter 13. In decanter 13, the combined flow is separated into flow 15, which contains dienes, aromatic hydrocarbons, and heteroatom-containing organic compounds, and flow 16, which contains organic solvents, water, dienes, aromatic hydrocarbons, and heteroatom-containing organic compounds. Flow 16 is supplied to distillation column 7, where it is separated into a top flow 8, which contains water, dienes, aromatic hydrocarbons, and heteroatom-containing organic compounds, and a bottom flow 9, which contains organic solvents. The organic solvent from bottom flow 9 is recycled via organic solvent flow 2. Flow 8 is fed into an overhead decanter 17 and separated into a flow 18 containing dienes, aromatic hydrocarbons, and heteroatom-containing organic compounds, and a flow containing water (which may further contain relatively small amounts of dienes, aromatic hydrocarbons, and heteroatom-containing organic compounds). A portion of the water flow (flow 19a) is returned to the distillation column 7 as reflux, and the other portion (flow 19b) may be recycled via water flow 14 and / or water flow 3 and / or water flow 10 and / or water flow 23.

[0150] In the process of Figure 2, the liquid hydrocarbon feed stream 1 described above is also first brought into contact with water, which is the washing solvent a) according to the present invention, first in the mixer 11 and decanter 20, and then in the extraction column 24. With respect to such upstream treatment of the feed stream in the process of Figure 2, the above description of the corresponding treatment in the process of Figure 1 is to be referenced, including optional contact with the sorbent indicated by "(X)" in Figure 2, relating to the mixer 11, stream 21, and stream 25, which represent the sorbent steps (i), (ii), and (iii) according to the present invention.

[0151] Furthermore, in the process shown in Figure 2, a stream 25 from extraction column 24 containing aliphatic hydrocarbons, dienes, aromatic hydrocarbons, and heteroatom-containing organic compounds, and a first solvent stream 2 containing an organic solvent (e.g., N-methylpyrrolidone), which is the extraction solvent b) according to the present invention, are supplied to the first extraction column 4a. In column 4a, the stream 25 comes into contact with the first solvent stream 2 (organic solvent), thereby recovering the aliphatic hydrocarbons by liquid-liquid extraction of the dienes, aromatic hydrocarbons, and heteroatom-containing organic compounds with the organic solvent. This results in a top stream 5a containing the recovered aliphatic hydrocarbons and organic solvent, and a bottom stream 6 containing the organic solvent, dienes, aromatic hydrocarbons, and heteroatom-containing organic compounds. The stream 5a and a second solvent stream 3 containing water, which is the washing solvent, are supplied to the second extraction column 4b. In column 4b, the stream 5a comes into contact with the second solvent stream 3 (water), thereby removing the organic solvent by liquid-liquid extraction of the organic solvent with water. The stream 5b containing the recovered aliphatic hydrocarbons exits the upper column 4b. Furthermore, the stream 14 containing the organic solvent and water (the water being the demixing solvent) exits from the bottom of column 4b. As indicated by "(X)" in Figure 2, the stream 5b may be brought into contact with the sorbent, which represents the sorbent step (iv) according to the present invention. The streams 6 and 14 are combined, and the combined stream is fed into the decanter 13. With respect to processing after the decanter 13, the downstream processing in the process of Figure 2 refers to the above description of the corresponding processing in the process of Figure 1.

Claims

1. A process for recovering aliphatic hydrocarbons from a liquid hydrocarbon feed stream containing aliphatic hydrocarbons, heteroatom-containing organic compounds, and optionally aromatic hydrocarbons, a) A step of mixing at least a portion of the liquid hydrocarbon supply stream with a washing solvent a) containing one or more heteroatoms, and separating the resulting mixture into a first stream containing the washing solvent a) and the heteroatom-containing compound, and a second stream containing aliphatic hydrocarbons, heteroatom-containing organic compounds, and optionally aromatic hydrocarbons, b) A step comprising bringing at least a portion of the second flow obtained from step a) into contact with an extraction solvent b) containing one or more heteroatoms, and subjecting the flow to liquid-liquid extraction with the extraction solvent b) to obtain a first flow containing aliphatic hydrocarbons and optionally heteroatom-containing organic compounds, and a second flow containing the extraction solvent b), heteroatom-containing organic compounds, and optionally aromatic hydrocarbons, (i) During step a), before the first and second flows are separated in step a), at least a portion of the liquid hydrocarbon feed stream is brought into contact with the sorbent, and / or (ii) step a) comprises a series of steps a) wherein at least a portion of the second flow obtained from the preceding step a) is brought into contact with the sorbent between the preceding step a) and the subsequent step a), and / or (iii) Between step a) and b), at least a portion of the second flow obtained from step a) is brought into contact with the sorbent, and / or (iv) A process wherein the first flow obtained from step b) comprises an aliphatic hydrocarbon and a heteroatom-containing organic compound, and after step b) at least a portion of the flow is brought into contact with an sorbent.

2. The washing solvent a) is at least 10 MPa １／２ Preferably, at least 15 MPa １／２ R ａ、ヘプタン It has R ａ、ヘプタン However, this refers to the Hansen solubility parameter distance for heptane, which is determined at 25°C. The process according to claim 1, wherein the washing solvent a) has a solubility of at least 0.1 g / 100 g, preferably at least 1 g / 100 g, of sodium chloride in g of NaCl per 100 g of solvent determined at 25°C.

3. The washing solvent a) is water, ammonia, and an organic solvent, and includes diols and triols (including monoethylene glycol (MEG), monopropylene glycol (MPG), and glycerol); glycol ethers (including oligoethylene glycols containing diethylene glycol, triethylene glycol, and tetraethylene glycol, and polyethylene glycol (PEG) which may have a molecular weight of 200 to 1,000 g / mol or 200 to 700 g / mol); amides (which may contain 1 to 8 or 1 to 3 carbon atoms in the alkyl group, and include methylformamide), including formamide, monoalkylformamide, and acetamide; dialkylsul The process according to claim 1 or 2, comprising one or more solvents selected from the group consisting of organic solvents selected from the group consisting of: hydroxyloxides (the alkyl group may contain 1 to 8 or 1 to 3 carbon atoms, and including dimethyl sulfoxide (DMSO)); sulfones (including sulfolanes); hydroxyesters (including methyl lactate and ethyl lactate, including lactate esters); amine compounds (including ethylenediamine, monoethanolamine, diethanolamine and triethanolamine); carbonate compounds (including propylene carbonate and glycerol carbonate); and cycloalkanone compounds (including dihydrolevoglucocenone), wherein the washing solvent a) preferably comprises water.

4. The extraction solvent b) is at least 5 MPa １／２ Preferably, at least 10 MPa １／２ R ａ、ヘプタン It has R ａ、ヘプタン The process according to any one of claims 1 to 3, wherein the distance is the Hansen solubility parameter distance for heptane, which is determined at 25°C.

5. The extraction solvent b) is ammonia, or preferably diols and triols (including any isomers of monoethylene glycol (MEG), monopropylene glycol (MPG), butanediol, and glycerol); glycol ethers (including diethylene glycol, triethylene glycol, and tetraethylene glycol, including oligoethylene glycol), and their monoalkyl ethers (including diethylene glycol ethyl ether); amides (including N-alkylpyrrolidone, where the alkyl group may contain 1 to 8 or 1 to 3 carbon atoms, including N-methylpyrrolidone (NMP)), formamides, and di and monoalkylformamides, and acetamides (where the alkyl group may contain 1 to 8 or 1 to 3 carbon atoms, including dimethylformamide (DMF), methylformamide, and dimethylacetamide); dialkyl sulfoxides (where the alkyl group may contain 1 to 8 or 1 to 3 carbon atoms, including dimethyl sulfoxide ( The process according to any one of claims 1 to 4, comprising one or more organic solvents selected from the group consisting of: DMSO; sulfones (including sulfolanes); N-formylmorpholine (NFM); furan ring-containing components and their derivatives (including furfural, 2-methylfuran, furfuryl alcohol and tetrahydrofurfuryl alcohol); hydroxyesters (including methyl lactate and ethyl lactate, including lactate esters); trialkyl phosphates (including triethyl phosphate); phenol compounds (including phenol and guaiacol); benzyl alcohol compounds (including benzyl alcohol); amine compounds (including ethylenediamine, monoethanolamine, diethanolamine and triethanolamine); nitrile compounds (including acetonitrile and propionitrile); trioxane compounds (including 1,3,5-trioxane); carbonate compounds (including propylene carbonate and glycerol carbonate); and cycloalkanone compounds (including dihydrolevoglucocenone).

6. (i) During step a), before the first and second flows are separated in step a), a portion of the heteroatom-containing organic compound is removed from the liquid hydrocarbon feed stream by contacting at least a portion of the liquid hydrocarbon feed stream with an sorbent to generate a treated flow, and at least a portion of the treated flow obtained from step (i) is supplied to step b) as the second flow obtained from step a), and / or (ii) A portion of the heteroatom-containing organic compound is removed from the second flow obtained from the preceding step a) by contacting at least a portion of the flow with an sorbent, and at least a portion of the treated flow obtained from step (ii) is supplied to the subsequent step a), and / or (iii) A portion of the heteroatom-containing organic compound is removed from the second flow obtained from step a) by contacting at least a portion of the flow with an sorbent, and at least a portion of the treated flow obtained from step (iii) is supplied to step b), and / or (iv) The process according to any one of claims 1 to 5, wherein the first flow obtained from step b) comprises an aliphatic hydrocarbon and a heteroatom-containing organic compound, and the heteroatom-containing organic compound is removed from the flow by bringing at least a portion of the flow into contact with an sorbent.

7. A process for recovering aliphatic hydrocarbons from plastic, wherein at least a portion of the plastic contains a heteroatom-containing organic compound, and the process is (I) A step of decomposing the plastic and recovering hydrocarbon products including aliphatic hydrocarbons, heteroatom-containing organic compounds, and optionally aromatic hydrocarbons, (II) A process comprising the step of subjecting a liquid hydrocarbon feed stream containing at least a portion of the hydrocarbon product obtained in step (I) to the process according to any one of claims 1 to 6.

8. A process for vapor decomposition of a hydrocarbon feedstock, wherein the hydrocarbon feedstock comprises an aliphatic hydrocarbon recovered in a process according to any one of claims 1 to 7.

9. A process for vapor decomposition of hydrocarbon feedstock, A process according to any one of claims 1 to 7, comprising the step of recovering aliphatic hydrocarbons from a liquid hydrocarbon feed stream, A process comprising the step of vapor-cracking a hydrocarbon feedstock containing aliphatic hydrocarbons recovered in a preceding step.

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