JP2023546118A - Recovery of aliphatic hydrocarbons - Google Patents

Abstract

The present invention is a process for recovering aliphatic hydrocarbons from a liquid stream comprising aliphatic hydrocarbons, heteroatom-containing organic compounds, and optionally aromatic hydrocarbons, the process comprising: a) extracting solvents from the liquid stream; liquid-liquid extraction thereby recovering a portion of the aliphatic hydrocarbons; b1) an extract stream comprising an extraction solvent, an aliphatic hydrocarbon, a heteroatom-containing organic compound, and optionally an aromatic hydrocarbon; b2) mixing the remaining stream with additional demixing solvent to recover additional aliphatic hydrocarbons, and b2) mixing the remaining stream with additional demixing solvent to recover heteroatom-containing organic compounds and optionally aromatic carbonization. and c) separating the remaining stream into a demixing solvent stream and an extraction solvent stream. Furthermore, the present invention provides a process for recovering aliphatic hydrocarbons from plastics, including the process described above, and a hydrocarbon feed comprising aliphatic hydrocarbons as recovered in one of the processes described above. relates to a process for steam decomposition of

Description

The present invention relates to a process for recovering aliphatic hydrocarbons from a liquid hydrocarbon feed stream comprising aliphatic hydrocarbons, heteroatom-containing organic compounds, and optionally aromatic hydrocarbons, including the processes described above. and to a process for steam cracking a hydrocarbon feed containing aliphatic hydrocarbons as recovered by one of the processes described above.

Waste plastics can be converted into high value-added chemicals, including olefins and aromatic hydrocarbons, for example through pyrolytic decomposition of the plastics. Pyrolysis of plastics can result in a product stream containing hydrocarbons with a wide boiling range. Hydrocarbons from such pyrolysis product streams are further cracked in a steam cracker to produce high-value chemicals, including ethylene and propylene, monomers that can be used to make new plastics. can do.

WO 2018/069794 discloses that olefins and A process for producing aromatic hydrocarbons is disclosed. Only the first fraction is fed to the liquid vapor cracker, whereas the second fraction is recycled to the pyrolysis device. In the process shown in Figure 1 of WO 2018/069794, the separation is performed in a hydrocarbon liquid distillation apparatus. Having to separate a liquid pyrolysis product stream into two fractions is cumbersome (eg, energy intensive). A further disadvantage is that the heavier portion of the liquid pyrolysis product stream must be sent back to the pyrolysis unit for deeper pyrolysis. This results in yield losses due to gas formation and increased amounts of solid by-products (coke) that are not ultimately sent to the steam cracker. In one embodiment of the process of WO 2018/069794 mentioned above (see Figure 2), the first fraction with a boiling point <300 °C is first conveyed to a hydroprocessing unit along with hydrogen and treated a hydrocarbon liquid stream that is then fed to a liquid vapor cracker. Such hydroprocesses are also cumbersome as they are capital intensive and require the use of expensive hydrogen ( _H2 ).

Furthermore, US Patent Publication No. 2018/0355256 discloses a method for deriving fuel from plastic, which method comprises subjecting an amount of plastic to a pyrolysis process, thereby deactivating at least a portion of the plastic. a first extraction step comprising: 1) a countercurrent liquid-liquid extraction using one or more extraction solvents to extract one or more impurities from the crude fuel; and 2) a first and extracting the fuel in a directly usable form by a second extraction step comprising countercurrent extraction of the contaminated extraction solvent obtained from the first extraction step. In the process illustrated in Figure 2 of U.S. Patent Publication No. 2018/0355256, crude fuel made by pyrolysis of plastics (i.e., crude diesel) is first converted to N-methyl-2-pyrrolidone (N-methyl -2-pyrrolidone, NMP) to extract one or more impurities, including sulfur compounds and aromatics, from the crude fuel. The contaminated NMP from the first extraction step is then subjected to a second extraction step using water to increase the polarity of the contaminated extraction solvent and thereby separate the impurities. In the final step, the water-contaminated NMP from the second extraction step is distilled using a standard distillation column to yield recycled water and recycled NMP.

The effluent from the extraction column used in the first extraction step, as disclosed in the above-mentioned US Patent Publication No. 2018/0355256 (Figure 2), contains heteroatom-containing organic contaminants and aromatic contaminants. In addition, it may still contain a certain amount of valuable aliphatic hydrocarbons. It is desirable to recover as much aliphatic hydrocarbons as possible and thus separate them from heteroatom-containing organic and aromatic contaminants. Upon such recovery, these additional aliphatic hydrocarbons are then recycled to the first extraction step or added to the first extraction step, so as to optimize the total recovery of aliphatic hydrocarbons. It can either be combined directly with the raffinate stream (refined diesel) from the extraction step. Such additional aliphatic hydrocarbons recovered may also be fed to a steam cracker instead of being used as fuel as disclosed in US Patent Publication No. 2018/0355256. However, such recovery of additional aliphatic hydrocarbons can be complicated by steps following the first extraction step, resulting in one or more effluent streams containing aliphatic hydrocarbons. , this effluent stream still additionally contains too high an amount of heteroatom-containing organic contaminants and aromatic contaminants to allow these effluent streams to be recycled or combined as described above.

In addition, the feed to a distillation column as disclosed in the above-mentioned US Patent Publication No. 2018/0355256 (Figure 2) still contains a certain amount of heteroatom-containing organic and aromatic contaminants. obtain. Such distillation may result in some of the contaminants being separated together with the recirculated water, which may result in the water and such contaminants forming an azeotrope, thereby causing the water to be recycled. This is because the quality of the circulating flow may be degraded. If the recirculated water is recycled to the column used in the second extraction step, the concentrations of these contaminants in the recirculated water will be lower than those in the recirculated NMP used in the first extraction step. In addition to the accumulation of substances, there is an increase in what is called "accumulation". This may result in lower efficiency of the first and second extraction steps. US Patent Publication No. 2018/0355256 relates to a method for deriving fuel from plastics. Such accumulation of these contaminants (in the recirculated NMP) can result in the clarified oil still containing relatively large amounts of these contaminants, which Because of the negative impact of these contaminants on yield, selectivity, and reliability, they are of particular concern when such clarified oils are fed to steam crackers instead of being used as fuel.

There is a continuing 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 stream may result from decomposing waste plastics in certain mixed waste plastics, particularly before feeding such recovered aliphatic hydrocarbons to a steam cracker. The object of the present invention is to provide such a process for the recovery of aliphatic hydrocarbons from such liquid streams, which process is technically advantageous, efficient and affordable, and in particular , as discussed above in connection with WO 2018/069794 and US Patent Publication No. 2018/0355256, is a process that does not have one or more of the above drawbacks. Such a technically advantageous process will preferably result in relatively low energy demands and/or relatively low capital expenditures.

International Publication No. 2018/069794 US Patent Application Publication No. 2018/0355256

Surprisingly, such a process comprises a) converting a liquid stream comprising a) an aliphatic hydrocarbon, a heteroatom-containing organic compound, and optionally an aromatic hydrocarbon into an extraction solvent a containing one or more heteroatoms; ) liquid-liquid extraction thereby recovering a portion of the aliphatic hydrocarbons, b1) the extraction solvent a) comprising the aliphatic hydrocarbons, heteroatom-containing organic compounds, and optionally aromatic hydrocarbons; , mixing the stream obtained from step a) with a demixing solvent b) to recover additional aliphatic hydrocarbons from the stream (demixing solvent b) containing one or more heteroatoms. and has lower miscibility in heptane than the miscibility of extraction solvent a) in heptane), b2) extraction solvent a), demixing solvent b), heteroatom-containing organic compound, and optionally an aromatic mixing the stream obtained from step b1) containing group hydrocarbons with an additional demixing solvent b) to remove heteroatom-containing organic compounds and optionally aromatic hydrocarbons; and c) extraction. providing at least a portion of the stream obtained from step b2), comprising solvent a) and demixing solvent b), by separating into a stream containing demixing solvent b) and a stream containing extraction solvent a); The present inventors have discovered that this is possible.

The present invention therefore relates to a process for recovering aliphatic hydrocarbons from a liquid hydrocarbon feed stream comprising aliphatic hydrocarbons, heteroatom-containing organic compounds, and optionally aromatic hydrocarbons, the process comprising:
a) contacting at least a portion of the liquid hydrocarbon feed stream with extraction solvent a) containing one or more heteroatoms, and subjecting the liquid hydrocarbon feed stream to liquid-liquid extraction with extraction solvent a); obtaining a first stream comprising an aliphatic hydrocarbon and a second stream comprising an extraction solvent a), an aliphatic hydrocarbon, a heteroatom-containing organic compound, and optionally an aromatic hydrocarbon; ,
b1) at least a portion of the second stream obtained from step a) contains one or more heteroatoms and has a miscibility in heptane that is lower than the miscibility of extraction solvent a) in heptane; and the resulting mixture is mixed with a first stream comprising aliphatic hydrocarbons and optionally aromatic hydrocarbons, extraction solvent a), demixing solvent b), heteroatoms separating into a second stream comprising organic compounds and optionally aromatic hydrocarbons;
b2) mixing at least a portion of the second stream obtained from step b1) with the demixing solvent b) and combining the resulting mixture with a second stream comprising a heteroatom-containing organic compound and optionally an aromatic hydrocarbon; separating one stream into a second stream comprising extraction solvent a) and demixing solvent b);
(steps b1) and b2) are substeps of step b) comprising two or more substeps),
c) separating at least a portion of the second stream obtained from step b2) into a first stream comprising the demixing solvent b) and a second stream comprising the extraction solvent a);
d) recycling at least a portion of the extraction solvent a) from the second stream obtained from step c) to step a); and e) optionally, the first stream obtained from step c). recycling at least a portion of the demixing solvent b) from the stream of step b) to one or more of the substeps of step b).

Advantageously, according to the invention, there is no need for a hydrogenation treatment (treatment with H ₂ ) for the liquid-liquid extraction in step a). Furthermore, liquid hydrocarbon streams having a wide boiling point range, such as plastic pyrolysis oils, can advantageously be treated in the present process with relatively low yield losses and feed degradation. This suggests that by applying the present invention, the cost of hydrocarbon feed to a steam cracker can be significantly reduced.

Furthermore, in step b) of the process of the invention, the demixing solvent b) is added to a certain amount of valuable aliphatic carbonization, rather than adding the entire amount of such demixing solvent b) in one step only. In the first sub-step b1), the aliphatic hydrocarbons and optionally the aromatic The stream comprising group hydrocarbons (first stream) is advantageously recovered, while the remaining stream comprising extraction solvent a), demixing solvent b), heteroatom-containing organic compounds, and optionally aromatic hydrocarbons. (second stream) is then mixed in a further substep b2) with another portion of the demixing solvent b), thereby advantageously containing heteroatom-containing organic compounds and optionally aromatic hydrocarbons (second stream). 1), resulting in a more efficient removal of the extraction solvent a) and the demixing solvent b) (second stream), which are then separated from each other in step c). Thus, in each substep b1), b2), and any further substeps in step b), the extraction solvent a) and the demixing solvent b) are separated from the stream (second stream) and recovered or removed. The composition of the stream (first stream) containing the compounds separated (ie, separated) varies as further explained below. This advantageously allows a fractional separation of the components extracted in step a) into a large number of different fractions, the number of which depends on the number of sub-steps in step b), Each may have different values and end uses.

Furthermore, according to the invention, the heteroatom-containing organic compounds and any aromatic hydrocarbons are advantageously removed in step b of the process, since the overall efficiency of the separation step b), including substeps b1) and b2), is increased. ) may ultimately not be substantially distributed or its amount may be reduced in the stream comprising the total extraction solvent a) and demixing solvent b). The heteroatom-containing organic compounds and aromatic compounds may include the most polar component of all the heteroatom-containing organic compounds and aromatic compounds extracted in step a) of the process. Advantageously, therefore, step b) in the process of the invention is substantially free of heteroatom-containing organic compounds and aromatic hydrocarbons originating from the liquid hydrocarbon feed stream, or free of these contaminants. A relatively pure demixing solvent b) recycle stream and a relatively pure extraction solvent a) recycle stream containing reduced amounts can be delivered in step c) of the process. Such pure demixed solvent b) stream can then advantageously be recycled and used to extract the extraction solvent a) either in step a) itself or in another additional step; Thereby, extraction solvent a) is prevented from entering the final hydrocarbon raffinate stream without contaminating such raffinate stream with heteroatom-containing organic compounds and aromatic hydrocarbons. Regarding the latter use of demixing solvent b) during recycling, that solvent is also referred to below as wash solvent c). Similarly, such pure extraction solvent a) stream from step c) is then advantageously recycled to step a) to remove further heteroatom-containing organic compounds and optional aromatics from the fresh feed. can be used to extract family hydrocarbons.

Therefore, advantageously, the accumulation of heteroatom-containing organic compounds and any aromatic hydrocarbons in the recycle stream in the present process is achieved by substeps b1) and b2) with stepwise addition of demixing solvent b). The separation step b) may be prevented or reduced as a whole. Therefore, it is not necessary or the need to apply other cumbersome methods to reduce the accumulation of these contaminants is substantially reduced. For example, there is no need, or the need is substantially reduced, to bleed a portion of the recycle stream prior to recycle, and (i) such bleed stream is discarded to reduce the loss of extraction solvent a). or (ii) extraction solvent a) may be recovered from such a bleed stream, for example by distillation thereof, but that is cumbersome.

Furthermore, the invention relates to a process for recovering aliphatic hydrocarbons from plastics, at least a portion of which comprises a heteroatom-containing organic compound, the process comprising:
(I) decomposing the plastic and recovering hydrocarbon products including aliphatic hydrocarbons, heteroatom-containing organic compounds, and optionally aromatic hydrocarbons;
(II) subjecting the liquid hydrocarbon feed stream comprising at least a portion of the hydrocarbon product obtained in step (I) to a process as described above for recovering aliphatic hydrocarbons from the liquid hydrocarbon feed stream; and a step of providing.

Still further, the present invention relates to a process for steam cracking a hydrocarbon feed, wherein the hydrocarbon feed comprises aliphatic hydrocarbons recovered in one of the above processes for the recovery of aliphatic hydrocarbons. Contains hydrogen.

1 shows an embodiment of a process for recovery of aliphatic hydrocarbons according to the present invention. 2 shows another embodiment of the above process. Includes results from experiments described in Example 2 below. Includes results from experiments described in Example 2 below. Includes results from experiments described in Example 2 below.

Each of the processes of the present invention includes multiple steps. Additionally, the process may include one or more intermediate steps between successive 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 includes steps a), b) and c), the process includes one or more intermediate steps between steps a) and b) and between steps b) and c). But that's fine. Furthermore, the process may include one or more additional steps before step a) and/or after step c).

As used herein, phrases such as "step y) comprises subjecting at least a portion of the flow obtained from step x)" to "step y) comprising subjecting at least a portion of the flow obtained from step x) to or similarly, "step y) includes subjecting, partially or completely, the stream obtained from step x) to "includes". For example, the stream obtained from step x) may be divided into one or more parts and at least one of these parts may be subjected to step y). Furthermore, for example, the flow obtained from step x) may be subjected to an intermediate step between step x) and step y) to obtain a further flow, at least a part of which is transferred to step y). You can also serve it.

Processes of the invention and streams and compositions used in the processes are defined as "comprising", "containing", or "comprising" each of one or more of the various described steps and components. (including), they can also "consist essentially of" or "consist of" one or more of the various recited steps and ingredients, respectively.

In the context of the present invention, if the stream contains more than one component, these components should be selected in a total amount not exceeding 100%.

Additionally, when upper and lower bounds of a property are cited, the range of values defined by the combination of any of the upper bounds and any of the lower bounds is also included.

As used herein, "substantially free" with respect to the amount of a particular component in a stream means up to 1,000, preferably up to 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). do.

Within this specification, "top flow" or "bottom flow" from a column is defined as 0% to 30%, more preferably 0%, based on the total length of the column, from the top of the column or the bottom of the column, respectively. % to 20%, even more preferably 0% to 10%, reference is made to the flow exiting the column.

Unless otherwise indicated, when reference is made herein to boiling point, this means the boiling point at a pressure of 760 mmHg (101.3 kPa).

Liquid Hydrocarbon Feed Stream In the present invention, the liquid hydrocarbon feed stream comprises aliphatic hydrocarbons, heteroatom-containing organic compounds, and optionally aromatic hydrocarbons.

Preferably, the liquid hydrocarbon feed stream comprises aliphatic hydrocarbons having a boiling point of 30 to 300°C and aliphatic hydrocarbons having a boiling point of over 300 to 600°C in a weight ratio of 99:1 to 1:99. Including both. The amount of aliphatic hydrocarbons with a boiling point of 30 to 300 °C is at most 99% by weight or at most 80% by weight or at most 60% by weight, based on the total amount of aliphatic hydrocarbons with a boiling point of 30 to 600 °C % or up to 40% or up to 30% or up to 20% or up to 10% by weight. Furthermore, the amount of aliphatic hydrocarbons having a boiling point of 30 to 300°C is at least 1% by weight or at least 5% by weight or at least 10% by weight, based on the total amount of aliphatic hydrocarbons having a boiling point of 30 to 600°C. or at least 20% or at least 30% by weight.

Advantageously, therefore, the liquid hydrocarbon feed stream may contain varying amounts of aliphatic hydrocarbons within a wide boiling point range of 30-600°C. Thus, like the boiling point, the number of carbon atoms of the aliphatic hydrocarbons in the liquid hydrocarbon feed stream can also vary within a wide range, for example from 5 to 50 carbon atoms. The carbon number of the aliphatic hydrocarbons in the liquid hydrocarbon feed stream may be at least 4 or at least 5 or at least 6 and may be at most 50 or at most 40 or at most 30 or at most 20.

The amount of aliphatic hydrocarbons in the liquid hydrocarbon feed stream is at least 30 wt.% or at least 50 wt.% or at least 80 wt.% or at least 90 wt.% or at least based on the total weight of the liquid hydrocarbon feed stream. It may be 95% or at least 99% by weight and less than 100% or at most 99% or at most 90% or at most 80% or at most 70%. Aliphatic hydrocarbons can be cyclic, linear, and branched.

Aliphatic hydrocarbons in the liquid hydrocarbon feed stream may include non-olefinic (paraffinic) and olefinic aliphatic compounds. The amount of paraffinic aliphatic compounds in the liquid hydrocarbon feed stream is at least 20% by weight, or at least 40% by weight, or at least 60% by weight, or at least 80% by weight, based on the total weight of the liquid hydrocarbon feedstream. and less than 100% or up to 99% or up to 80% or up to 60% by weight. Additionally, the amount of olefinic aliphatic compounds in the liquid hydrocarbon feed stream is less than 100% by weight, or at least 20% by weight, or at least 40% by weight, or at least 60% by weight, based on the total weight of the liquid hydrocarbon feedstream. % or at least 80% by weight and up to 99% or up to 80% or up to 60% by weight.

Furthermore, olefinic compounds may include aliphatic compounds with one carbon-carbon double bond (monoolefins) and/or aliphatic compounds with two or more carbon-carbon double bonds, the latter compound being , can be conjugated or unconjugated. That is, two or more carbon-carbon double bonds may be conjugated or non-conjugated. Aliphatic compounds having two or more carbon-carbon double bonds may include compounds having double bonds in the alpha and omega positions. The amount of monoolefins in the liquid hydrocarbon feed stream may be at least 20 wt% or at least 40 wt% or at least 60 wt% or at least 80 wt%, based on the total weight of the liquid hydrocarbon feed stream; and may be less than 100% or up to 99% or up to 80% or up to 60% by weight. Further, the amount of conjugated aliphatic compounds having two or more carbon-carbon double bonds in the liquid hydrocarbon feed stream is greater than 0% by weight, based on the total weight of the liquid hydrocarbon feed stream; or at least 10%, or at least 20%, or at least 40%, or at least 60%, and up to 80%, or up to 60%, or up to 40%.

Within this specification, an aliphatic hydrocarbon containing one or more heteroatoms is a "heteroatom-containing organic compound", as further described below. Unless explicitly indicated otherwise by context, the term "aliphatic hydrocarbon" herein does not include heteroatom-containing aliphatic hydrocarbons. Furthermore, unless explicitly indicated otherwise by context, the term "aliphatic hydrocarbon" herein does not include conjugated aliphatic compounds having two or more carbon-carbon double bonds. .

In addition to the aliphatic hydrocarbons mentioned above, the liquid hydrocarbon feed stream includes heteroatom-containing organic compounds and optionally aromatic hydrocarbons.

The amount of aromatic hydrocarbons in the liquid hydrocarbon feed stream is 0% by weight, or greater than 0% by weight, or at least 5% by weight, or at least 10% by weight, based on the total weight of the liquid hydrocarbon feedstream. % or at least 15% or at least 20% or at least 25% or at least 30% by weight and up to 50% or at most 40% or at most 30% or at most 20% by weight. could be. 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-fused and/or fused polycyclic aromatic hydrocarbons. An example of a non-fused polycyclic aromatic hydrocarbon is oligostyrene. Styrene and oligostyrene can be derived from polystyrene. Examples of fused polycyclic aromatic hydrocarbons are naphthalene and anthracene, and alkylnaphthalene and alkylanthracene. One or more aromatic rings in aromatic hydrocarbons may be substituted with one or more hydrocarbyl groups, including alkyl groups (saturated) and alkylene groups (unsaturated).

Within this specification, aromatic hydrocarbons containing one or more heteroatoms are "heteroatom-containing organic compounds" as further explained below. Unless explicitly indicated otherwise by context, the term "aromatic hydrocarbon" herein does not include heteroatom-containing aromatic hydrocarbons.

Furthermore, the amount of heteroatom-containing organic compounds in the liquid hydrocarbon feed stream is greater than 0 wt.%, at least 0.5 wt.%, or at least 1 wt.%, based on the total weight of the liquid hydrocarbon feed stream. 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 up to 30% by weight or at most 20% by weight or at most 10% by weight or at most It can be 5% by weight.

The heteroatom-containing organic compound in the liquid hydrocarbon feed stream contains one or more heteroatoms, which may be oxygen, nitrogen, sulfur and/or halogen (e.g. chlorine), preferably oxygen, nitrogen and/or halogen. Contains. Heteroatom-containing organic compounds include one or more of the following moieties: amines, imines, nitriles, alcohols, ethers, ketones, aldehydes, esters, acids, amides, carbamates (sometimes called urethanes), and ureas. But that's fine.

Furthermore, the heteroatom-containing organic compounds mentioned above may be aliphatic or aromatic. An example of an aliphatic heteroatom-containing organic compound is oligomeric polyvinyl chloride (PVC). Oligomeric PVC may be derived from polyvinyl chloride. The aromatic heteroatom-containing organic compound 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 can be derived from polyethylene terephthalate. Examples of nitrogen-containing organic compounds are compounds derived from polyamides, including polyurethanes and nylons.

Unless explicitly indicated otherwise by context, the term "heteroatom-containing organic compound" as used herein refers to a heteroatom in or derived from a liquid hydrocarbon feed stream. It means the contained organic compound. Furthermore, unless explicitly indicated otherwise by context, the term "heteroatom-containing organic compound" as used herein refers to extraction solvents, demixing solvents, and/or washing solvents as defined herein. Does not include.

Additionally, the liquid hydrocarbon feed stream can include salt. The salts may include organic and/or inorganic salts. Salts may include ammonium, alkali metals, alkaline earth metals, or transition metals as cations, and carboxylates, sulfates, phosphates, or halides as anions.

Preferably, at least some of the components in the liquid hydrocarbon feed stream, including aliphatic hydrocarbons, heteroatom-containing organic compounds, and optionally aromatic hydrocarbons, are synthetic compounds, e.g. It is not a natural compound such as exists in For example, such synthetic compounds include compounds derived from the pyrolysis of plastics synthesized from biomass, such as polyethylene synthesized from bioethanol by ethanol dehydration and subsequent polymerization of the ethylene so formed. is included.

Furthermore, because heteroatom-containing organic compounds are readily removed in the process, the feedstock to the process can advantageously tolerate relatively large amounts of such heteroatom-containing organic compounds. Therefore, the waste plastics that can be pyrolyzed to produce the feedstock to this process are heteroatom-based materials such as polyvinyl chloride (PVC), polyethylene terephthalate (PET) and polyurethane (PU). Contains plastics. Specifically, mixed waste plastics containing heteroatom-free plastics such as polyethylene (PE) and polypropylene (PP) as well as relatively large amounts of such heteroatom-containing plastics are heated. Can be disassembled.

Step a) - Extraction with extraction solvent a) In step a) of the process, at least a portion of the liquid hydrocarbon feed stream comprising aliphatic hydrocarbons, heteroatom-containing organic compounds, and optionally aromatic hydrocarbons is removed. , contacting at least a portion of the liquid hydrocarbon feed stream with extraction solvent a) containing one or more heteroatoms, providing a liquid hydrocarbon supply; The feed stream is subjected to liquid-liquid extraction with extraction solvent a) to separate a first stream comprising the aliphatic hydrocarbons and extraction solvent a), the aliphatic hydrocarbons, the heteroatom-containing organic compound, and optionally the aromatic. and a second stream containing group hydrocarbons.

In step a) of the process, the liquid hydrocarbon feed stream may be fed to a first column (first extraction column). Furthermore, the first solvent stream comprising extraction solvent a) may be fed to the first column at a higher position than the liquid hydrocarbon feed stream is fed, thereby resulting in a countercurrent liquid-liquid extraction. the top stream from the first column (the "first stream" above) containing the aliphatic hydrocarbons and the extraction solvent a), the aliphatic hydrocarbons, the heteroatom-containing organic compound, and optionally the aromatic a bottoms stream from the first column (the "second stream" above) containing group hydrocarbons.

In step a), the weight ratio of extraction solvent a) to liquid hydrocarbon feed stream is 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 at most 5:1 or at most 3:1 or at most 2:1 or at most 1:1. Furthermore, the temperature in step a) 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 at most 200°C or at most 150°C or at most 100°C or at most It may be 70°C or up to 60°C or up to 50°C or up to 40°C. The pressure in step a) may be at least 100 bara or at least 500 bara or at least 1 bara or at least 1.5 bara or at least 2 bara and 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 It can be 5 bara or at most 3 bara or at most 2 bara or at most 1.5 bara. The temperature and pressure in step a) are preferably such that both the hydrocarbon from the feed stream and the extraction solvent a) are in the liquid state.

In step a), a portion of the aliphatic hydrocarbons is recovered by liquid-liquid extraction of the heteroatom-containing organic compounds and optionally the aromatic hydrocarbons with extraction solvent a). Furthermore, preferably the recovered aliphatic hydrocarbons are aliphatic hydrocarbons with a boiling point of 30 to 300°C and aliphatic with a boiling point of over 300 to 600°C in a weight ratio of 99:1 to 1:99. Contains hydrocarbons. With respect to aliphatic hydrocarbons in a liquid hydrocarbon feed stream, the above description of the weight ratio of aliphatic hydrocarbons with a boiling point between 30 and 300 °C and aliphatic hydrocarbons with a boiling point above 300 and 600 °C also applies. , applies to recovered aliphatic hydrocarbons.

In step a), the liquid-liquid extraction comprises a first stream comprising an aliphatic hydrocarbon and an extraction solvent a), an aliphatic hydrocarbon, a heteroatom-containing organic compound, and optionally an aromatic hydrocarbon. and the second flow. Within this specification, the former stream (first stream) containing recovered aliphatic hydrocarbons may also be referred to as the "raffinate stream" and the latter stream (second stream) as the "extract stream". It can also be called. Such a raffinate stream has a 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 is free or contains at most 10% by weight or at most 5% by weight or at most 1% by weight or is substantially free of aromatic hydrocarbons. Furthermore, such raffinate stream is free of conjugated aliphatic compounds having two or more carbon-carbon double bonds, or at most 15% by weight, or at most 10% by weight, or at most 5% by weight, or at most 1% by weight, or substantially free. Furthermore, such a raffinate stream is free, contains at most 1% by weight, or is substantially free of heteroatom-containing organic compounds.

The extraction solvent a) used in step a) of the process may be fed to the first column in step a) as a first solvent stream, but preferably is less dense than the liquid hydrocarbon feed stream. also has a density that is at least 3% or at least 5% or at least 8% or at least 10% or at least 15% or at least 20% higher. Further, 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 liquid hydrocarbon feed stream.

Furthermore, the extraction solvent a) used in step a) contains one or more heteroatoms, which may be oxygen, nitrogen and/or sulfur. Still further, it is preferred that the extraction solvent a) is thermally stable at a temperature of 200<0>C. Still further, the extraction solvent a) 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. Still further, it is preferred that the extraction solvent a) has no or relatively low miscibility in heptane. Preferably, extraction solvent a) is at most 30% by weight or at most 20% by weight or at most 10% by weight or at most 3% by weight or at most 1% by weight of extraction solvent a), based on the weight of heptane. are miscible in heptane such that they are 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. When referring herein to the miscibility of one compound to another, this means miscibility at 25°C.

Furthermore, the extraction solvent a) in step a) has a pressure of at least 3 MPa ^1/2 , preferably at least 5 MPa ^1/2 , more preferably at least 10 MPa ^1/2 , preferably at least 15 MPa with respect to heptane as determined at 25°C. _{Heptane may have a Hansen solubility parameter distance R a} of ^1/2 . Furthermore, the R _{a for extraction solvent a), heptane} , is less than 45 MPa ^1/2 or at most 40 MPa ^1/2 , preferably at most 35 MPa ^1/2 , more preferably at most 30 MPa ^1/2 , more preferably It can be up to 25 MPa ^1/2 . For example, the R _{a for N-methylpyrrolidone (NMP), heptane} , is 15 MPa ^1/2 .

Still further, said extraction solvent a) has a Hansen solubility parameter distance R a for toluene of at least 1.5 MPa ^1/2 , preferably at least 2 MPa ^1/2 when determined at 25° C. compared to _toluene. may have a Hansen solubility parameter distance R _{a for heptane} (ie, R _{a, heptane} -R _{a, toluene} ). Furthermore, the difference in R _{a for extraction solvent a),} R _{a compared to toluene, heptane} may be at most 4.5 MPa ^1/2 , preferably at most 4 MPa ^1/2 .

Hansen solubility parameters (HSP) can be used as a means to predict the potential of one component relative to another. More specifically, each component is characterized by three Hansen parameters, each generally expressed in MPa ^0.5 , where δ _d indicates the energy from intermolecular dispersion forces, and δ _p represents the energy from intermolecular dispersion forces. δ h indicates the energy from the bipolar intermolecular forces between the molecules, and δ _h indicates the energy from the hydrogen bonds between the molecules. The affinity between compounds can be described using a multidimensional vector that quantifies the atomic and intermolecular interactions of these solvents as the Hansen solubility parameter (HSP) distance R _a defined by equation (1). Can:
(R _a ) ² = 4 (δ _d2 - δ _d1 ) ² + (δ _p2 - δ _p1 ) ² + (δ _h2 - δ _h1 ) ² (1)
During the ceremony,
R _a = distance in HSP space between compound 1 and compound 2 (MPa ^0.5 )
δ _d1 , δ _p1 , δ _h1 = Hansen (or equivalent) parameters of compound 1 (MPa ^0.5 )
δ _d2 , δ _p2 , δ _h2 = Hansen (or equivalent) parameters of compound 2 (MPa ^0.5 )

Therefore, the lower the value of R _a for a given solvent calculated with respect to the compound being recovered (i.e., the compound being recovered is Compound 1 and the solvent is Compound 2, or vice versa), the more This increases the affinity of this solvent for the compound being treated.

Hansen solubility parameters for a number of solvents are described in, among others, the 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.

Specifically, the extraction solvent a) used in step a) of the process is ammonia or preferably diols and triols (monoethylene glycol (MEG), monopropylene glycol (MPG)). , butanediol and any isomer of glycerol); glycol ethers (including oligoethylene glycols, including diethylene glycol, triethylene glycol and tetraethylene glycol), and their monoalkyl ethers (including diethylene glycol ethyl ether); amides (including N-alkylpyrrolidones, where the alkyl group may contain 1 to 8 or 1 to 3 carbon atoms, including N-methylpyrrolidone (NMP)), formamide, and di- and monoalkyl formamide, and acetamide (the alkyl group may contain 1 to 8 or 1 to 3 carbon atoms and includes dimethyl formamide (DMF), methyl formamide, and dimethyl acetamide); The group may contain 1 to 8 or 1 to 3 carbon atoms, including dimethylsulfoxide (DMSO); sulfone (including sulfolane); N-formyl morpholine, NFM); furan ring-containing components and their derivatives (including furfural, 2-methylfuran, furfuryl alcohol and tetrahydrofurfuryl alcohol); hydroxy esters (including lactate, including methyl lactate and ethyl lactate); phosphoric acid Trialkyl (including triethyl phosphate); Phenolic compounds (including phenol and guaiacol); Benzyl alcohol compounds (including benzyl alcohol); Amine compounds (including ethylenediamine, monoethanolamine, diethanolamine and triethanolamine); Nitriles compounds (including acetonitrile and propionitrile); trioxane compounds (including 1,3,5-trioxane); carbonic acid compounds (including propylene carbonate and glycerol carbonate); and cycloalkanone compounds (including dihydrol evoglucosenone) ) may include one or more organic solvents selected from the group consisting of:

More preferably, said extraction solvent a) comprises a dialkyl sulfoxide as described above, in particular DMSO; a sulfone, in particular sulfolane; an N-alkylpyrrolidone as mentioned above, in particular NMP; and a furan ring-containing component, in particular contains one or more of furfural. Even more preferably, said extraction solvent a) comprises one or more of the above-mentioned N-alkylpyrrolidones, in particular NMP, and a furan ring-containing component, in particular furfural. Most preferably extraction solvent a) comprises NMP.

Aqueous solutions of quaternary ammonium salts in particular trioctylmethylammonium chloride or methyltributylammonium chloride can also be used as extraction solvent a) in step a).

In addition to extraction solvent a), a wash solvent such as water may be added to step a). This wash solvent is referred to herein as wash solvent c) and is further explained below. In such a case, step a) preferably comprises a first stream comprising an aliphatic hydrocarbon and a washing solvent c), an extraction solvent a), an aliphatic hydrocarbon, a heteroatom-containing organic compound, and optionally an aromatic and a second stream containing group hydrocarbons. Advantageously, therefore, said washing solvent c) added in step a) acts as an extraction solvent to extract the extraction solvent a), thereby removing the recovered aliphatic hydrocarbons obtained from step a). the first stream comprising extraction solvent a) is free or substantially free of extraction solvent a). If washing solvent c) is also added in step a), the weight ratio of extraction solvent a) to washing solvent c) in step a) is at least 0.5:1 or at least 1:1 or at least 2:1 or It may be at least 3:1 or at most 30:1 or at most 25:1 or at most 20:1 or at most 15:1 or at most 10:1 or at most 5:1 or at most 3:1. 1 or at most 2:1.

If wash solvent c) is also added to step a), the second solvent stream containing wash solvent c) is provided at a higher position than the first solvent stream mentioned above containing extraction solvent a) is supplied. The top stream from the first column containing the aliphatic hydrocarbons (the first a bottoms stream from the first column (stream 1 above) containing washing solvent c), extraction solvent a), aliphatic hydrocarbons, heteroatom-containing organic compounds, and optionally aromatic hydrocarbons. 2)). In the above case, the first solvent stream in the extraction step a) may comprise, in addition to the extraction solvent a), a demixing solvent b), such as water, and/or an optional washing solvent c) as described above. Demixing solvent b) is also explained further below. The demixing solvent b) and washing solvent c) may originate from one or more recycle streams after step c) of the process.

If wash solvent c) is also added to step a), the stream containing added wash solvent c) is free or substantially free of heteroatom-containing organic compounds derived from the liquid hydrocarbon feed stream. Preferably not. This preference is such that, as mentioned above, the stream is fed to the first extraction column at a relatively high position and these heteroatom-containing organic compounds recontaminate the raffinate (top) stream obtained from step a). This is especially true if there is a possibility. Advantageously, according to the invention, at least a portion of the demixing solvent b)-containing stream obtained from step c) (heteroatom-containing (which may be free or substantially free of organic compounds) can be used as such wash solvent c) stream for feeding (recirculation) to step a).

As mentioned above, the second stream obtained from step a) (the stream for the first (extraction) column described above corresponds to the bottom stream from such a column) contains extraction solvent a) , aliphatic hydrocarbons, heteroatom-containing organic compounds, and optionally aromatic hydrocarbons. The stream may additionally contain salts and/or conjugated aliphatic compounds having two or more carbon-carbon double bonds if such salts and/or compounds are present in the liquid hydrocarbon feed stream. can be included.

In the present invention, extraction solvent a) is recovered from the second stream obtained from step a) and then advantageously recycled to step a) through steps b), c) and d) of the process. be done.

Step b) - Demixing with solvent b) Throughout step b) of the process, step a comprises extraction solvent a), an aliphatic hydrocarbon, a heteroatom-containing organic compound, and optionally an aromatic hydrocarbon. ) into a demixing solvent b) containing one or more heteroatoms and having a miscibility in heptane that is lower than the miscibility of extraction solvent a) in heptane. ) and the resulting mixture is mixed in at least two substeps, for example 2 to 5 substeps, preferably 2 or 3 substeps, to one comprising an extraction solvent a) and a demixing solvent b). The stream is separated into another stream containing compounds that are separated from the previous stream. That is, in each of these substeps there is a mixing with demixing solvent b) followed by separation of the resulting stream, and the separated stream comprising extraction solvent a) and demixing solvent b) is The demixing is fed to the next substep where it is mixed with an additional portion of solvent b). By adding the demixing solvent b) stepwise (stepwise or incrementally) in several portions in this way, instead of adding the entire amount of the demixing solvent b) in only one step, the substep The relative amount of demixing solvent b) in each separated stream (second stream) comprising extraction solvent a) and demixing solvent b) leaving the extraction solvent a) and demixing solvent b) increases gradually, and after each substep, the relative amount of demixing solvent b) in said second stream becomes less hydrophobic. Thereby, advantageously, in each substep, the compounds that are separated, recovered or removed (i.e. separated) from the stream (second stream) comprising extraction solvent a) and demixing solvent b) are The composition of the containing stream (first stream) is different. Advantageously, the amount of aliphatic hydrocarbons in the first stream obtained from the first sub-step in step b) is relatively high, which makes it possible to recover from such additional aliphatic hydrocarbons. this may be recycled to step a) and/or the raffinate stream obtained from step a), preferably such a raffinate stream, is brought into contact with the washing solvent c). May be combined before being fed into the optional additional steps described below. On the other hand, the relative amounts of heteroatom-containing organic compounds and optionally aromatic hydrocarbons in the first stream obtained from the later (downstream) sub-step in step b) are relatively high, thereby ) makes it possible to remove these contaminants from the process without losing significant amounts of the additional aliphatic hydrocarbons already recovered in the previous substep.

Therefore, in step b1) of the process, also referred to herein as sub-step b1), at least a portion of the second stream obtained from step a) is mixed with demixed solvent b) to obtain The mixture comprises a first stream comprising an aliphatic hydrocarbon and optionally an aromatic hydrocarbon, an extraction solvent a), a demixing solvent b), a heteroatom-containing organic compound, and an optional aromatic hydrocarbon. and a second stream containing

Furthermore, in step b2) of the process, thus also referred to herein as sub-step b2), at least a portion of the second stream obtained from step b1) is mixed with demixing solvent b); The resulting mixture is separated into a first stream comprising the heteroatom-containing organic compound and optionally an aromatic hydrocarbon and a second stream comprising the extraction solvent a) and the demixing solvent b).

Furthermore, the demixing solvent b) used in step b) contains one or more heteroatoms, which may be oxygen, nitrogen and/or sulfur. Still further, just like extraction solvent a), the demixing solvent b) preferably has no miscibility or relatively low miscibility in heptane. Preferably, the demixing solvent b) is at most 10% by weight or at most 3% by weight or at most 1% by weight or at most 0.5% by weight or at most 0.1% by weight, based on the weight of heptane. The demixing solvent b) is miscible in heptane such that it is miscible in heptane. In the present invention, the miscibility of the demixing solvent b) in heptane is lower than the miscibility of the extraction solvent a) in heptane. The miscibility of the solvents a) and b) in heptane can be determined by any common method known to those skilled in the art, including ASTM method D1476, described above. Furthermore, the demixing solvent b) is preferably miscible with the extraction solvent a). This means that up to 50% by weight of demixing solvent b), based on the total amount of demixing solvent b) and extraction solvent a), can be mixed in extraction solvent a).

Furthermore, the demixing solvent b) in step b) is at least 10 MPa ^1/2 , preferably at least 20 MPa ^1/2 , more preferably at least 30 MPa ^1/2 , preferably at least 40 MPa ¹ with respect to heptane determined at 25°C. _{Heptane may have a Hansen solubility parameter distance R a} of ^/2 . Furthermore, the R _{a for demixing solvent b), heptane} , may be at most 55 MPa ^1/2 , more preferably at most 50 MPa ^1/2 , more preferably at most 45 MPa ^1/2 . For example, the R _{a for water, heptane} , is 45 MPa ^1/2 .

As mentioned above, the miscibility of extraction solvent a) and demixing solvent b) in heptane is different. Therefore, the solvents a) and b) are not the same. Specifically, demixing solvent b) may have a Hansen solubility parameter distance R _{a for heptane determined at 25° C.,} which corresponds to such a R _{a for extraction solvent a),} Bigger than _heptane . Preferably, the difference in R _{a , heptane} for solvents a) and b) 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 the difference in R _{a for solvents a) and b), heptane} is at most 55 MPa ^1/2 , more preferably at most 50 MPa ^1/2 , more preferably at most 45 MPa ^1/2 , and more Preferably at most 40 MPa ^1/2 , more preferably at most 35 MPa ^1/2 , more preferably at most 30 MPa ^1/2 .

In particular, the demixing solvent b) used in step b) of the process is one or more selected from the group consisting of water and a solvent from the group of solvents defined above for extraction solvent a). It may also contain a solvent. Preferably, the demixing solvent b) comprises water and one or more of the diols and triols mentioned above, in particular monoethylene glycol (MEG) and glycerol. More preferably, the demixing solvent b) comprises water, most preferably consists of water. Other preferences and embodiments mentioned above regarding extraction solvent a) used in step a) are that demixing solvent b) is not identical to extraction solvent a) as it has lower miscibility in heptane; This also applies to demixing solvent b), with the exception that solvent b) may, and preferably does, contain water.

In the process of the invention, step b) comprises two or more substeps, including steps b1) and b2) which are substeps of step b). Preferably, the process comprises 2 to 10, more preferably 2 to 5 substeps in step b). The number of sub-steps in step b) is at least 2, may be at least 3 or at least 4, and may be at most 10 or at most 8 or at most 6.

For example, if step b) comprises two substeps, in the first substep aliphatic hydrocarbons and any aromatic hydrocarbons are rejected via the first stream obtained from step b1). In a second substep, the heteroatom-containing organic compound may be removed via the first stream obtained from step b2).

Step b) of the process may therefore include more than two substeps. For example, if step b) includes three substeps, the first substep may exclude aliphatic hydrocarbons and the second substep may exclude any aromatic hydrocarbons. In a third substep, heteroatom-containing organic compounds can be excluded.

Furthermore, in particular, if the process comprises more than two sub-steps in step b), step b)
bi) mixing at least a portion of the second stream obtained from step a) with a demixing solvent b) and combining the resulting mixture with a first stream comprising aliphatic hydrocarbons and optionally aromatic hydrocarbons; and a second stream comprising extraction solvent a), demixing solvent b), aliphatic hydrocarbons, heteroatom-containing organic compounds, and optionally aromatic hydrocarbons;
bii) mixing at least a portion of the second stream obtained from step bi) with the demixing solvent b) and combining the resulting mixture with aliphatic hydrocarbons, heteroatom-containing organic compounds, and optionally aromatics. separating into a first stream comprising a group hydrocarbon and a second stream comprising an extraction solvent a), a demixing solvent b), a heteroatom-containing organic compound, and optionally an aromatic hydrocarbon;
biii) mixing at least a portion of the second stream obtained from step bii) with the demixing solvent b) and combining the resulting mixture with a second stream comprising a heteroatom-containing organic compound and optionally an aromatic hydrocarbon; 1 stream and a second stream comprising extraction solvent a) and demixing solvent b), and step c) comprises separating the second stream obtained from step biii). into a first stream comprising the demixing solvent b) and a second stream comprising the extraction solvent a).

An additional advantage of the above process comprising substeps bi), bii) and biii) is obtained from step bii), in which (i) aliphatic hydrocarbons and (ii) heteroatom-containing organic compounds and optionally aromatic It is not necessary to discard the first stream containing both hydrocarbons, even if the relative amounts of heteroatom-containing organic contaminants and any aromatic contaminants are too high to feed to a steam cracker. However, it can still be used as fuel. Said substep bi) corresponds to substep b1), while said substep biii) corresponds to substep b2).

Accordingly, in the present invention, the composition of the various first streams obtained from at least two substeps in step b) can advantageously be varied by increasing or decreasing the number of substeps. , can also be varied by varying the relative amounts of demixing solvent b) that are mixed in each of these substeps with the stream obtained from the preceding step. Such changes result in different partition coefficients in each substep, preferentially leading certain compounds to either the more hydrophobic first stream or the less hydrophobic second stream. . The need for such changes, in turn, depends on the desires for each of the first streams (cracker feed, internal recycle, fuel, potentially valuable products (e.g., solvent), or waste). may depend on the composition of the feed to step b) and/or indirectly the composition of the liquid hydrocarbon feed stream fed to step a).

Furthermore, each of the second streams obtained from the substeps in step b) may additionally contain salt. Any conjugated aliphatic compound having two or more carbon-carbon double bonds, together with the heteroatom-containing organic compound and optionally the aromatic hydrocarbon, can be added to the first or second compound obtained from substep b). This can lead to the flow of Generally, in the present invention, the conjugated aliphatic compounds can behave similarly to aromatic compounds, so that they can lead to the same stream or streams as the optional aromatic hydrocarbons.

In each of the substeps of step b), the demixing solvent b) is used separately from the second stream obtained from step a) or the second stream obtained from the preceding substep of step b), and It is added in addition to any demixing solvent b) that may be present in one of the latter streams and is mixed with one of the latter streams. In each of the substeps of step b), at least a portion of the first stream obtained from step a), which first stream comprises the recovered aliphatic hydrocarbons and extraction solvent a), of a second stream comprising washing solvent c), such as water, and extraction solvent a) obtained from the optional additional extraction step described below, subjected to liquid-liquid extraction with washing solvent c). At least a portion may be added to provide the demixing solvent b) that needs to be added in step b).

The mixing in each of the substeps of step b) may be carried out in any manner known to those skilled in the art. For example, a mixer can be used upstream of a phase separation device as described below. Furthermore, for example, in-line (or static) mixing may be performed upstream of such a phase separation device. Still further, mixing may be performed in a column as described below.

Through such addition of the demixing solvent b) and mixing in each of the substeps of step b), the more hydrophobic first phase and the more hydrophobic phase comprising the extraction solvent a) and the demixing solvent b) Different phases are formed, including a lower second phase, which are separated in each substep into the first stream and the second stream, respectively. Advantageously, therefore, said demixing solvent b added in step b) separately from the second stream obtained from step a) or the second stream obtained from the preceding substep in step b). ) acts as a so-called "demixing agent" (or "anti-solvent"), thereby removing the more hydrophobic compounds from the extraction solvent a) for recovery and recycling.

The phase separation in each of the substeps of step b) may be carried out by any device capable of separating two phases, including decanters, flotation devices, coalescers and centrifuges, preferably decanters. The phase separation in each of the substeps of step b) is preferably carried out in a single stage, for example in a decanter, flotation device, coalescer or centrifuge. For example, if a decanter is used in step b), the first upper phase containing the more hydrophobic compound and the extraction solvent a), the demixing solvent b) and optionally the less hydrophobic compound (i.e. and a second lower phase containing compounds (of lower hydrophobicity than the compounds in the first phase) can be separated into the first stream and the second stream, respectively.

Furthermore, each of the substeps of step b) may be performed in a separate column comprising multiple separation stages. In the latter case, each sub-step comprises at least a portion of the second stream obtained from step a) or at least a portion of the second stream obtained from the preceding sub-step in step b), respectively. demixing solvent b) in the column and separating the resulting mixture into a first stream as described above and a second stream, preferably a top stream from the column (above "first stream"). ) and a bottoms stream from the column (the "second stream" above). Preferably, the streams enriched in the demixing solvent b) and the other extraction solvent a) are fed co-currently to the column at the bottom of the column.

The internals within the column contribute to the mixing of the extraction solvent a)-enriched stream with the demixing solvent b). The internals of such columns are known in the art. The internal structure of the column may include packings such as Raschig rings, Paul rings, Lessing rings, Bierreck rings, Dixon rings; sieve plates; or random structures such as those described in Perry's Chemical Engineer's Handbook, among others. May contain fillings. Furthermore, the column may be provided with stirring means. For example, a shaft may extend along the column and there may be a rotor and a stator fixed to the column.

Still further, in the present invention a single column comprising multiple separation stages may be used for step b) as a whole comprising multiple substeps. The columns that can be used in such a case may be the same as those described above for the case where each of the substeps of step b) is carried out in a separate column. When using such a single column, step b) of the process is:
b1) feeding at least a portion of the second stream obtained from step a) and the demixed solvent b) to a first section of the column, mixing them, and supplying at least a portion of the second stream obtained from step a) and the demixed solvent b) to the first section; removing a stream from the first section at a location downstream of the feed location and combining the extracted stream with the first stream comprising the aliphatic hydrocarbons and optionally the aromatic hydrocarbons and the extraction solvent a); separating into a second stream comprising a mixed solvent b), a heteroatom-containing organic compound, and optionally an aromatic hydrocarbon;
b2) Feeding at least a portion of the second stream obtained from step b1) and the demixing solvent b) to a second section of the column located downstream of the first section, mixing and demixing them. withdrawing a stream from the second section at a location downstream of the location at which the mixed solvent b) is fed to the second section; 1 stream and a second stream comprising extraction solvent a) and demixing solvent b).

In the above case where a single column is used for multiple substeps in step b), the second stream obtained from step b2) is added to the second column of the column, as described further below. may be partially or completely fed to the next section located downstream of the section of step 1 or may be recovered as a second stream comprising extraction solvent a) and demixing solvent b), at least a portion of which c).

Furthermore, in the above cases where a single column is used for multiple substeps in step b), the first section of such a column may be located at the top or at the bottom of the column. Furthermore, preferably the demixing solvent b) and the second stream obtained from step a) are fed in cocurrent to the first section of the column. In each substep of step b), phase separation may be carried out by any device capable of separating two phases, including decanters, flotation devices, coalescers and centrifuges, preferably decanters. Phase separation therefore takes place within such a phase separation device located outside the column. Furthermore, the column can comprise one or more further sections positioned downstream of the second section, in which case the additional demixing solvent b) is also added to the first section obtained from the previous substep. 2 streams are fed separately to each of these additional sections, which are mixed in such additional sections, and the streams from such additional sections are such that the demixing solvent b) The withdrawn stream is withdrawn at a location downstream of the location where it is fed to that additional section, the withdrawn stream comprising a first stream containing the compounds to be separated from the demixing solvent b) and the extraction solvent a) and the extraction solvent a). and a second stream comprising demixed solvent b).

Furthermore, the above description of temperature and pressure in extraction step a) also applies to the above substeps in step b) as a whole. Still further, in the entire step b), the demixing solvent b), i.e. the total demixing solvent b added in that sub-step, is based on the amount of extraction solvent a) in the second stream obtained from step a). ) and extraction solvent a) may be at least 0.005:1 or at least 0.01:1 or at least 0.5:1 or at least 1:1 or at least 2:1, up to It may be 10:1 or up to 7:1 or up to 5:1 or up to 4:1 or up to 2:1. Preferably, throughout step b), the total amount of demixing solvent b) added in all the substeps of step b) comprises (i) that total amount of demixing solvent b) and (ii) from step a). Based on the amount of extraction solvent a) in the second stream obtained, from 0.1 to 45% by weight, more preferably from 1 to 40% by weight, more preferably from 5 to 35% by weight, more preferably may be 10 to 30% by weight.

Thus, throughout step b) of the present process, the additional aliphatic hydrocarbons may advantageously be recovered separately from the heteroatom-containing organic compounds and any aromatic hydrocarbons, the latter compounds being advantageously are removed from the recycled extraction solvent a) and there is therefore no need to separate the extraction solvent a) from such removed compounds in a later step. Furthermore, any aromatic hydrocarbons and conjugated aliphatic compounds having two or more carbon-carbon double bonds removed in step b) are advantageously blended with pygas and processed into fuels, or Or it can be used to produce aromatic compounds. Similarly, the heteroatom-containing organic compound removed in step b) may be converted into a fuel, optionally after hydrogenation treatment to remove the heteroatoms. Furthermore, the compounds removed in step b) can be further separated into various fractions that can be used as solvents.

Step c) - Separation of extraction solvent a) and demixing solvent b) In step c) of the process, a second At least a portion of the stream is separated into a first stream containing the demixing solvent b) and a second stream containing the extraction solvent a). If any washing solvent c) described below is used in the invention, this washing solvent c) may be the same or different, preferably the same, as the demixing solvent b); Such wash solvent c) may pass into said second stream obtained from the last sub-step of step b) and subsequently into said first stream obtained from step c).

The feed stream to step c) thus comprises at least a portion of the second stream obtained from the last sub-step of step b). In step c), demixing solvent b) and extraction solvent a) may be separated from each other in any known manner, preferably by evaporation, for example by distillation. The latter separation may be performed in a distillation column. Advantageously, in the distillation, at least a portion of any heteroatom-containing organic compounds and aromatic hydrocarbons in the feed stream to step c) are removed azeotropically with the demixing solvent b), in particular water. .

Step c) therefore comprises combining at least a portion of the second stream obtained from the last sub-step of step b) by distillation into a top stream comprising the demixing solvent b) and a bottom stream comprising the extraction solvent a). Preferably, the method includes separating into a stream. If the feed stream to step c) additionally comprises heteroatom-containing organic compounds and optionally aromatic hydrocarbons, the top stream additionally comprises such compounds.

Furthermore, if the feed stream to step c) additionally contains salt, the second stream obtained from step c) additionally contains such salt. If the feed stream to step c) or the second stream obtained from step c) contains any solid salts, they may be removed therefrom by any method including filtration.

In the present invention, the amount of demixing solvent b) in the feed stream to step c) may be at least 10% by weight or at least 20% by weight and at most 70% by weight or at most 50% by weight or at most It may be 40% by weight. The second stream obtained from step c) still contains the demixing solvent b) in an amount of, for example, at most 10% by weight or at most 5% by weight or at most 3% by weight or at most 1% by weight. But that's fine. Advantageously, if the amount of demixing solvent b) in said second stream is relatively low, e.g. up to 5% by weight, such demixing solvent b) is equal to the extraction solvent from said same stream. There is no need for a) to be removed before being recycled to step a) of the process.

As mentioned above, the feed stream to the above distillation step as step c) in the process contains, in addition to extraction solvent a) and demixing solvent b), heteroatom-containing organic compounds and optionally aromatic hydrocarbons. , the top stream obtained from the distillation step comprises demixed solvent b), heteroatom-containing organic compounds, and optionally aromatic hydrocarbons. Advantageously, in the distillation at least a portion of the heteroatom-containing organic compounds and aromatic hydrocarbons are removed azeotropically with the demixing solvent b), in particular water. In the latter case, the top stream can be separated into two phases, one phase containing the demixing solvent b) and another phase containing the heteroatom-containing organic compound and optionally the aromatic hydrocarbon. . Such phase separation can be performed by any device capable of separating two phases, including decanters, flotation devices, coalescers and centrifuges, preferably decanters. Advantageously, the demixing solvent b) from such separated phase containing the demixing solvent b) may be recycled as explained further below, while the other phases are added to the process. may be bled from the base, thereby reducing the risk of any accumulation of heteroatom-containing organic compounds and aromatic hydrocarbons in the process.

Recycling Step In step d) of the process, at least a portion of the extraction solvent a) from the second stream obtained from step c) is recycled to step a).

The second stream obtained from step c) may additionally contain aromatic hydrocarbons and/or heteroatom-containing organic compounds. If the stream containing extraction solvent a) recycled to step a) contains relatively large amounts of such compounds, preventing any accumulation of these contaminants in such recycled stream to step a). Additional demixing solvent b) may be added to step b) so as to do so. Furthermore, these contaminants may be removed by bleeding a portion of the stream containing extraction solvent a) recycled to step a) before recycling extraction solvent a) to step a). Often such a bleed stream can be discarded or the extraction solvent a) can be recovered from such a bleed stream, for example by distillation thereof.

Furthermore, in optional step e) of the process, at least a portion of the demixed solvent b) from the first stream obtained from step c) is recycled to one or more of the substeps of step b). It is circulated.

The latter recycling in step e) to one or more substeps of step b) ensures that the first stream obtained from step c) contains a relatively large amount of heterogeneous gas derived from the liquid hydrocarbon feed stream. Suitable if it still contains atom-containing organic compounds and/or aromatic hydrocarbons. However, such streams may be free or substantially free of heteroatom-containing organic compounds and/or aromatic hydrocarbons, or contain relatively small amounts of heteroatom-containing organic compounds and/or aromatic hydrocarbons. (this is advantageously made possible by the entire separation step b) comprising at least two substeps), if a washing solvent c) such as water is added to step a) as described above, or recycling at least a portion of the demixing solvent b) from such stream to step a) when added to the optional additional extraction step below in which such wash solvent c) is added; is preferred.

Separation of extraction solvent a) from the raffinate stream The stream containing recovered aliphatic hydrocarbons obtained from the liquid-liquid extraction with extraction solvent a) in step a) (raffinate stream) additionally contains extraction solvent a) In this case, extraction solvent a) is preferably separated from that stream, which is the first stream obtained from step a), and optionally recycled to step a). In this way, the recovered aliphatic hydrocarbons are advantageously separated from any extraction solvent a) in the raffinate stream described above, and the separated extraction solvent a) is advantageously separated from step a). can be recycled.

Extraction solvent a) is used to extract the above first stream obtained from step a) (which stream comprises aliphatic hydrocarbons and extraction solvent a) in any manner including distillation, extraction, absorption, and membrane separation. may be separated from the above-mentioned streams obtained from

In particular, in the above case where the first stream obtained from step a) comprises aliphatic hydrocarbons and extraction solvent a), in an additional step at least a part of said first stream is washed. contact with solvent c) and subject to liquid-liquid extraction with washing solvent c) to obtain a first stream comprising aliphatic hydrocarbons and a second stream comprising washing solvent c) and extraction solvent a) .

In the present invention, an optional wash that can be used in the additional extraction step described above or can be added separately to step a) or added together with extraction solvent a) in the flow to step a) Solvent c) may be the same as or different from demixing solvent b), preferably the same. The above preferences and embodiments for demixing solvent b) also apply to optional washing solvent c). Preferably, the washing solvent c) comprises water, more preferably consists of water. Furthermore, preferably both the demixing solvent b) and the washing solvent c) contain water, more preferably consist of water.

In an additional step above, the first stream obtained from step a) and comprising aliphatic hydrocarbon and extraction solvent a) may be fed to a second column (second extraction column). Furthermore, the second solvent stream comprising wash solvent c) may be fed to the second column at a higher position than the position at which the first stream obtained from step a) is fed, thereby a top stream from a second column (above "first stream") allowing countercurrent liquid-liquid extraction and containing an aliphatic hydrocarbon, and a second column containing a wash solvent c) and an extraction solvent a) provides a bottom flow (the "second flow" above) from the

Advantageously, therefore, said washing solvent c) added in said additional step serves as an extraction solvent for extracting extraction solvent a), thereby advantageously retaining the recovered aliphatic hydrocarbons in the recovered aliphatic hydrocarbons. to be free or substantially free of extraction solvent a). In the above additional step, the weight ratio of extraction solvent a) to washing solvent c) may be at least 0.5:1 or at least 1:1 or at least 2:1 or at least 3:1, up to at 30:1 or at most 25:1 or at most 20:1 or at most 15:1 or at most 10:1 or at most 5:1 or at most 3:1 or at most 2:1 good. Furthermore, the above description of temperature and pressure in extraction step a) also applies to the additional (extraction) step described above. If the process comprises the above-mentioned additional steps, the first solvent stream in extraction step a) may include a demixing solvent b) in addition to extraction solvent a), in which case the first solvent stream from the first extraction column The bottom stream additionally contains demixed solvent b).

In the additional step above in which wash solvent c) is added, the stream comprising added wash solvent c) is free or substantially free of heteroatom-containing organic compounds derived from the liquid hydrocarbon feed stream. It is preferable not to include it. This preference is useful when, as mentioned above, the stream is fed to a second extraction column at a relatively high position and these heteroatom-containing organic compounds can recontaminate the raffinate (top) stream. This is especially true. Advantageously, in the present invention, at least a portion of the first stream obtained from step c) and comprising the demixing solvent b) and optionally the washing solvent c), which originates from the liquid hydrocarbon feed stream (which may be free or substantially free of heteroatom-containing organic compounds) is fed to said additional step, in particular if the demixing solvent b) is the same as the washing solvent c), in particular water. Such a washing solvent c) can be used as a stream (for recirculation).

Furthermore, at least a portion of the second stream comprising washing solvent c) and extraction solvent a) obtained from the above-mentioned addition (extraction) step is fed to step b), in particular when the demixing solvent b) is washed. If it is the same as solvent c), it is possible to provide at least a portion of the demixing solvent b) that needs to be added in step b). Advantageously, therefore, such a washing solvent c) is used as an extraction solvent to extract the residual extraction solvent a) in said additional step and as a so-called "demixing agent" (or "anti-solvent") in step b). It can function both as a demixing solvent b), i.e. as discussed further above.

If a wash solvent other than water is fed to the extraction column for extracting extraction solvent a) used in step a), such a In addition to other solvents, it may be preferred that water is fed to the extraction column at a higher level than the other solvents are fed. In this way, advantageously, the water fed at a higher position can extract any wash solvent other than water, thereby allowing such other wash solvents to enter the (final) raffinate stream. prevent entry. Alternatively, the latter raffinate stream may be washed with water in a separate step.

Upstream and Downstream Integration In the present invention, the liquid hydrocarbon feed stream comprises at least a portion of the hydrocarbon products formed in a process involving the decomposition of plastics, preferably waste plastics, more preferably mixed waste plastics. and at least a portion of the plastic contains a heteroatom-containing organic compound.

The invention therefore also relates to a process for recovering aliphatic hydrocarbons from plastics, at least a portion of which comprises a heteroatom-containing organic compound, the process comprising:
(I) decomposing the plastic and recovering hydrocarbon products including aliphatic hydrocarbons, heteroatom-containing organic compounds, and optionally aromatic hydrocarbons;
(II) subjecting the liquid hydrocarbon feed stream comprising at least a portion of the hydrocarbon product obtained in step (I) to a process as described above for recovering aliphatic hydrocarbons from the liquid hydrocarbon feed stream; and a step of providing.

The preferences and embodiments described above as such with respect to the present aliphatic hydrocarbon recovery process also apply to step (II) of the present process for recovering aliphatic hydrocarbons from plastics. In step (I) above, the hydrocarbon product obtained may be either liquid or solid or waxy. 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).

In the above process, at least a portion of the plastic fed to step (I) comprises a heteroatom-containing organic compound, and this plastic is preferably a waste plastic, more preferably a mixed waste plastic. In said step (I), the decomposition of the plastic may involve a pyrolysis 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, more preferably 500-600°C. Additionally, any pressure may be applied, and the pressure may be subatmospheric, atmospheric, or superatmospheric. The heat treatment in step (I) causes melting of the plastic and decomposition of its molecules into smaller molecules. The decomposition in step (I) can be carried out as thermal decomposition or as liquefaction. In both pyrolysis and liquefaction, a continuous liquid phase is formed. In addition, in pyrolysis, a discontinuous gas phase is formed, which escapes the liquid phase and separates into a continuous gas phase. In liquefaction, there is no significant gas phase by applying relatively high pressures.

Furthermore, in step (I), the subsequent condensation of the gas phase and/or cooling of the liquid phase comprises aliphatic hydrocarbons, heteroatom-containing organic compounds, and optionally aromatic hydrocarbons. a hydrocarbon product, at least a portion of which is subjected to the aliphatic hydrocarbon recovery process described above in step (II).

Step (I) above may be performed in any known manner, for example as disclosed in the above-mentioned WO 2018/069794 and WO 2017/168165, the disclosures of which are incorporated herein by reference. It can be done in the same way as shown.

Advantageously, the aliphatic hydrocarbons recovered in one of the above processes for the recovery of aliphatic hydrocarbons may contain varying amounts of aliphatic hydrocarbons within a wide boiling point range. , the above-mentioned WO 2018/069794 may be fed to the steam cracker without further pretreatment, such as treatment with hydrogen (hydrotreatment or hydroprocessing). In addition to being used as a feed to a steam cracker, the recovered aliphatic hydrocarbons may also be advantageously subjected to hydrocracking, isomerization, hydrotreating, thermal catalytic cracking, and fluid catalytic cracking. may be fed to other purification processes including Moreover, in addition to being used as a feed to a steam cracker, the recovered aliphatic hydrocarbons can also be advantageously used in different gaseous products, each of which can find different uses such as diesel, marine fuel, solvents, etc. May be separated into minutes.

The invention therefore also relates to a process for the steam cracking of a hydrocarbon feed, wherein the hydrocarbon feed comprises aliphatic hydrocarbons recovered in one of the above-mentioned processes for the recovery of aliphatic hydrocarbons. Contains hydrogen. Furthermore, the present invention therefore also provides a process for steam cracking of a hydrocarbon feed, comprising the step of steam cracking aliphatic hydrocarbons from a liquid hydrocarbon feed stream in one of the above processes for the recovery of aliphatic hydrocarbons. and steam cracking the hydrocarbon feed, the hydrocarbon feed comprising aliphatic hydrocarbons recovered in a previous step. As used herein, the phrase "steam cracking a hydrocarbon feedstock containing the aliphatic hydrocarbons recovered in the previous step" refers to "steam cracking a hydrocarbon feedstock containing at least a portion of the recovered aliphatic hydrocarbons." can mean "to steam decompose". The hydrocarbon feed to the steam cracking process may also include hydrocarbons from other sources than the present process for recovery of aliphatic hydrocarbons. Such other sources may be naphtha, hydrowax, or a combination thereof.

Advantageously, the liquid hydrocarbon feed stream is an aromatic hydrocarbon, especially a polycyclic aromatic, a heteroatom-containing organic compound, a conjugated aliphatic compound having two or more carbon-carbon double bonds, or a combination thereof. , these have already been removed by the present aliphatic hydrocarbon recovery process described above before feeding the recovered hydrocarbons to the steam cracking process. This means that the removed compounds, especially polycyclic aromatics, are present in the preheat, convection, and radiant sections of the steam cracker, as well as in the heat exchange and/or separation equipment downstream of the steam cracker, e.g. It is particularly advantageous in that it no longer causes fouling in transfer line exchangers (TLE) used for rapid cooling of effluent from. When hydrocarbons condense, they can thermally decompose into coke layers and cause fouling. Such fouling is a major factor in determining the run length of the cracker. Reducing the amount of fouling increases run time without shutting down maintenance and improves exchanger heat transfer.

Steam cracking may be performed in any known manner. The hydrocarbon feed is typically preheated. The feed can be heated using a heat exchanger, a furnace, or any other combination of heat transfer and/or heating devices. The feed is steam cracked in a cracking zone under cracking conditions to produce at least olefins (including ethylene) and hydrogen. The decomposition zone may include any decomposition system known in the art suitable for decomposing the feed. The cracking zone may include one or more furnaces, each dedicated to a particular feed or fraction of the feed.

The decomposition is carried out at elevated temperatures, preferably in the range of 650-1000°C, more preferably in the range of 700-900°C, most preferably in the range of 750-850°C. Steam is typically added to the cracking zone and acts as a diluent to reduce hydrocarbon partial pressure and thereby increase olefin yield. The steam also reduces the formation and deposition of carbonaceous material or coke in the cracking zone. Decomposition occurs in the absence of oxygen. Residence times at decomposition conditions are very short, typically on the order of milliseconds.

A cracker effluent is obtained from the cracker which may contain aromatics (produced in the steam cracking process), olefins, hydrogen, water, carbon dioxide, and other hydrocarbon compounds. The specific products obtained depend on the feed composition, hydrocarbon to steam ratio, and cracking temperature and furnace residence time. The cracked products from the steam cracker are then passed through one or more heat exchangers, often referred to as TLEs ("transfer line exchangers"), to rapidly reduce the temperature of the cracked products. . TLE preferably cools the decomposition products to a temperature in the range of 400-550°C.

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

In the process of Figure 1, aliphatic hydrocarbons (including conjugated aliphatic compounds having two or more carbon-carbon double bonds (hereinafter referred to as "dienes")), aromatic hydrocarbons and heteroatom-containing a liquid hydrocarbon feed stream 1 comprising an organic compound; a first solvent stream 2 comprising an organic solvent (for example N-methylpyrrolidone) which is extraction solvent a) according to the invention; and an optional washing according to the invention. A second solvent stream 3 containing water as solvent c) is fed to the extraction column 4. In column 4, liquid hydrocarbon feed stream 1 is contacted with a first solvent stream 2 (organic solvent), thereby liquid-liquid extraction of dienes, aromatic hydrocarbons, and heteroatom-containing organic compounds with the organic solvent. Aliphatic hydrocarbons are recovered by Furthermore, the water in the second solvent stream 3 removes the organic solvent from the top of the column 4 by liquid-liquid extraction of the organic solvent with water. Stream 5 containing the recovered aliphatic hydrocarbons leaves the upper column 4. A stream 6, which further comprises organic solvents, water, aliphatic hydrocarbons, dienes, aromatic hydrocarbons, and heteroatom-containing organic compounds, leaves the bottom of column 4.

Additionally, in the process of FIG. 1, stream 6 and stream 14a containing additional water are combined and the combined stream is fed to first decanter 13a. The water stream 14a and the lower water streams 14b and 14c are sub-streams split off from the water stream 14, the water in which being the demixed solvent b) according to the invention. In the decanter 13a, the combined stream is separated into a stream 15a containing aliphatic hydrocarbons and a stream 16a containing organic solvents, water, aliphatic hydrocarbons, dienes, aromatic hydrocarbons, and heteroatom-containing organic compounds. Ru. Stream 16a and stream 14b containing additional water are then combined and the combined stream is fed to the second decanter 13b. In decanter 13b, the combined streams are a stream 15b containing aliphatic hydrocarbons, dienes, aromatic hydrocarbons, and heteroatom-containing organic compounds, and a stream 15b containing organic solvents, water, dienes, aromatic hydrocarbons, and heteroatom-containing organic compounds. and a stream 16b containing the compound. Finally, stream 16b and stream 14c containing additional water are combined and the combined stream is fed to the third decanter 13c. In decanter 13c, the combined streams are stream 15c containing dienes, aromatic hydrocarbons, and heteroatom-containing organic compounds, organic solvent, water, and reduced amounts of dienes, aromatic hydrocarbons, and heteroatom-containing organic compounds. and a stream 16c containing the compound.

Still further, in the process of FIG. 1, stream 16c is fed to distillation column 7 and comprises a top stream 8 containing water, dienes, aromatic hydrocarbons, and heteroatom-containing organic compounds, and a bottom stream 9 containing organic solvent. separated into Organic solvent from bottom stream 9 is recycled via organic solvent stream 2. Stream 8 is fed to an overhead decanter 17 and contains a stream 18 containing dienes, aromatic hydrocarbons, and heteroatom-containing organic compounds, and a stream containing water (which contains relatively small amounts of dienes, aromatic hydrocarbons, and a portion of the aqueous stream (stream 19a) is returned as reflux to the distillation column 7, and another portion (stream 19b) is separated into aqueous stream 14 (which may additionally contain heteroatom-containing organic compounds). and/or may be recycled via the water stream 3.

In the process of Figure 2, aliphatic hydrocarbons (including conjugated aliphatic compounds having two or more carbon-carbon double bonds, hereinafter referred to as "dienes"), aromatic hydrocarbons, and heteroatom-containing A liquid hydrocarbon feed stream 1 comprising a compound and a first solvent stream 2 comprising an organic solvent (for example N-methylpyrrolidone), which is extraction solvent a) according to the invention, are is supplied to the extraction column 4a. In column 4a, liquid hydrocarbon feed stream 1 is contacted with a first solvent stream 2 (organic solvent and water), thereby liquidating dienes, aromatic hydrocarbons, and heteroatom-containing organic compounds with the organic solvent. - recovery of aliphatic hydrocarbons by liquid extraction, resulting in a top stream 5a comprising recovered aliphatic hydrocarbons and organic solvents, organic solvents, water, dienes, aromatic hydrocarbons and heteroatom-containing organic compounds; A bottom flow 6 is generated. Stream 5a and a second solvent stream 3 comprising water (which is the optional wash solvent c according to the invention) are fed to a second extraction column 4b. In ram 4b, stream 5a is contacted with a second solvent stream 3 (water), thereby removing the organic solvent by liquid-liquid extraction of the organic solvent with water. Stream 5b containing recovered aliphatic hydrocarbons leaves the upper column 4b. Furthermore, a stream 14 comprising organic solvent and water leaves the bottom of column 4b and is divided into substreams 14a, 14b and 14c, the water in which being the demixed solvent b) according to the invention. Streams 6 and 14a are combined and the combined stream is fed to the first decanter 13a. Regarding the processing after the decanter 13a, the downstream processing in the process of FIG. 2 refers to the above description of the corresponding processing in the process of FIG. Optionally (not shown in FIG. 2), an additional substream 14d can be split off from stream 14 and fed directly to distillation column 7.

The invention is further illustrated by the following examples.

Example 1
In Example 1, waste plastic pyrolysis oil is used, as determined by a two-dimensional gas chromatography (GC×GC) method, where GC utilizes a Flame Ionization Detector (FID). had the following composition: light components with less than 7 carbon atoms (<C7) (8.7% by weight), paraffins (25% by weight), olefins (26.3% by weight), naphthenes. (13.9% by weight), aromatic (12.2% by weight), polycyclic aromatic (1.9% by weight), heteroatom-containing organic compounds (12.1% by weight), chloride content (approx. 900ppmw), nitrogen content (about 300ppmw), oxygen content (about 1200ppmw). Furthermore, the waste plastic pyrolysis oil had a density of 777 kg/m ³ .

Under laboratory conditions, 250 ml of waste plastic pyrolysis oil, the liquid hydrocarbon feedstock according to the invention, was mixed with 250 ml of dry N-methyl-2-pyrrolidone (NMP), the extraction solvent a) according to the invention. Mixed for 5 minutes. The NMP is also referred to herein as a solvent. NMP has a density of 1027 kg/ ^m3 . The resulting mixture is then left to form (i) an upper oil phase containing aliphatic hydrocarbons (also referred to herein as the "first oil phase") and (ii) NMP as well as waste plastic pyrolysis. A lower solvent phase (also referred to herein as extract or "first solvent phase") comprising compounds extracted from the oil into a solvent containing aliphatic hydrocarbons, heteroatom-containing organic compounds, and aromatic hydrocarbons. It was separated into The first oil phase had a lower density than the first solvent phase. The volume of the first solvent phase was 114% by volume based on the volume of the hydrocarbon feedstock. This means that the compound was extracted into the solvent from the waste plastic pyrolysis oil.

The first solvent phase was then separated from the first oil phase by decantation. Furthermore, water (which is the demixing solvent b according to the invention) was added to the separated first solvent phase in an amount of 7.4% by volume, based on the volume of the first solvent phase. Therefore, the volume ratio of the first solvent phase to the added water was 13.5. After mixing for 5 minutes, the mixture was allowed to separate into a second oil phase and a second solvent phase containing water and NMP. The volume of the second oil phase was approximately 10% by volume based on the volume of the mixture. The phases were separated by decantation.

Additional water was then added to the separated second solvent phase in an amount of 65% by volume based on the volume of the second solvent phase. Therefore, the volume ratio of the second solvent phase to the added water was 1.5. After mixing for 5 minutes, the mixture was allowed to separate into a third oil phase and a third solvent phase containing water and NMP. The volume of the third oil phase was approximately 3.6% by volume based on the volume of the mixture. The phases were separated by decantation.

Changes in the color appearance of some recovered oil phases can be considered qualitative evidence of changes in the composition of these oil phases. Oils rich in aliphatic compounds (containing no heteroatoms) have a translucent appearance (water-like) and are colorless. In contrast, many compounds with several double bonds between carbon atoms and/or between carbon atoms and heteroatoms are colored. The intensity of the color darkness of the excluded oil phase is somewhat proportional to the concentration of compounds containing such double bonds. In Example 1, the first oil phase is clearer in appearance than the third oil phase, which is much darker in color and exhibits a change in composition, as further confirmed in Examples 2 and 3 below. Ta.

Example 2
In Example 2, the same waste plastic pyrolysis oil used in Example 1 was contacted with the same dry organic solvent (NMP) in an extraction column at 40° C. and atmospheric pressure. The pyrolysis oil was a dispersed phase (droplets) and was introduced into the bottom of the extraction column at a flow rate of 12 kg/h. The solvent (NMP) was the continuous phase and was introduced at the top of the column at a flow rate of 23.8 kg/h. The volume flow ratio of oil to solvent was 1:1.5. The extract phase was generated at the bottom of the extraction column and the raffinate phase was generated at the top.

The extract contained NMP solvent as well as N, Cl and O contaminants from the hydrocarbon feed. The relative amounts of these N, Cl, and O contaminants in the raffinate were substantially reduced compared to those in the feed, as shown in the table below.

A sample of 1380 ml of the extract (first solvent phase) was taken. The extract contains a continuous phase (no phase separation, no second phase) and is represented by the first data point in Figure 3 below. A determined amount of demineralized water (desalted water) was added and mixed with the extract sample for approximately 5 minutes. The mixture was then allowed to separate into two phases, after which the two phases were separated by decantation. The displaced oil phase was removed for quantification and analysis. Additional water was then added to the resulting extract phase. These steps were performed sequentially to produce a total of nine different excluded oil phases. The successive amounts of demineralized water added at each step as a percentage of the initial extract volume (which was 1380 ml) were, correspondingly, 2, 2, 2, 4, 7, 14, 22, 29, 36% by volume. Met. The volume of each displaced oil phase was also recorded.

Figure 3 shows on the x-axis the cumulative amount of water added to the solvent phase based on the initial extract volume (which was 1380 ml). For example, in the first water addition step, water was added in an amount of 2% by volume based on the amount of initial extract volume. Furthermore, in the second water addition step, an amount of 2% by volume of water based on the amount of the initial extract volume was also added, and an amount of 4% by volume based on the amount of the initial extract volume was added. brought about the cumulative amount of water.

Additionally, Figure 3 shows on the y-axis the cumulative amount of oil phase based on the initial extract volume (which was 1380 ml). As seen in Figure 3, by adding only about 2% water by volume to the first solvent phase in the first water addition step, a relatively large amount of hydrocarbon compounds other than NMP are transferred to the first solvent phase. Advantageously removed (excluded) from the solvent phase. Additionally, lower and lower relative amounts of such other compounds were removed by adding additional water in subsequent water addition steps.

As shown in Figure 3, not only was the relative amount of oil phases separated for all water addition steps different, but advantageously the composition of each of these oil phases was also different. This is shown in FIGS. 4 and 5.

FIG. 4 shows on the x-axis the cumulative amount of oil phase based on the volume of the first solvent phase ("extract") and on the y-axis the amount of such chloride in the first solvent phase. Figure 4 shows the cumulative amount of chloride-containing organic compounds (measured by Combustion Ion Chromatography, CIC) based on the total volume of organic compounds contained. chloride-containing organic compounds are removed from the solvent phase, whereas the subsequent water addition step indicates that relatively more chloride-containing organic compounds are removed from the solvent phase. The oil phase obtained from the water addition step contains relatively large amounts of aliphatic hydrocarbons (does not contain heteroatoms such as chlorine), whereby advantageously there is no stepwise addition of water, but The overall recovery of such aliphatic hydrocarbons is increased compared to when the same total (cumulative) amount of water is added in a single water addition step.

Furthermore, FIG. 5 shows the results of gas chromatography (GC)-Field Ionization Mass Spectrometry (FIMS) analysis of the separated oil phase obtained from the continuous addition of water. In FIG. 5, "oil phase decanter 1" means the second oil phase separated in the first water addition step. "Oil phase decanter 3" means the fourth oil phase separated in the third water addition step, and "oil phase decanter 5" means the sixth oil phase separated in the fifth water addition step. means. In Figure 5, Double Bond Equivalent (DBE) is plotted as a function of the number of carbons in the compound from the oil phase. A relatively large dot in FIG. 5 means that the relative amount of a compound with a particular number of carbons and DBE is relatively large. DBE represents the level of unsaturation in organic compounds. The higher the DBE, the greater the number of unsaturated carbon-carbon bonds and/or ring structures. Figure 5 also shows that continuous (stepwise) addition of water results in a shift in the composition of the oil phase containing organic compounds excluded by the solvent phase containing increasing amounts of water in addition to NMP. For example, paraffinic (unsaturated) organic compounds with a relatively high carbon number are mainly rejected into the oil phase in the first water addition step (see "oil phase decanter 1" in FIG. 5). As more water is added, the resulting solvent phase comprising water and NMP has a relatively high number of unsaturated carbon-carbon bonds and/or ring structures and/or a relatively low number of carbon atoms. Relatively more organic compounds began to be excluded (see "Oil phase decanters 3 and 5" in Figure 5).

Example 3
In Example 3, the findings of Example 1 and Example 2 and the accompanying effects of the present invention were confirmed as follows.

Process simulation in Aspen Plus V11 was set up as follows. In the simulation, a stream containing representative components of waste plastic pyrolysis oil was used (see "Waste plastic oil feedstock" in Tables 1, 2, and 3 below), which is a liquid hydrocarbon according to the present invention. is the feedstock stream. Ingredients selected from the Aspen Plus component library include paraffins, olefins and naphthenes, oxygen-containing aromatics (“O-aromatics”), chlorine-containing aromatics (“Cl-aromatics”), polycyclic aromatics aromatic compounds (does not contain heteroatoms such as O and Cl); and other aromatic compounds (does not contain heteroatoms such as O and Cl). The relative amounts of these components in the feed are shown in Table 1. The basic thermodynamic method chosen is UNIF-LL, which is a commonly recommended characterization method for liquid-liquid equilibrium applications.

The feed stream (oil) is introduced into the first extraction column and the extraction solvent a) according to the invention, the solvent N-methyl-2-pyrrolidone (NMP), is introduced at 200 kg/h and 100 kg/h, respectively, for simulation purposes. Add at a 2:1 solvent to oil mass ratio with a corresponding flow rate of . The oil phase ("raffinate") and the first solvent phase ("extract") are produced in a raffinate to extract mass ratio of 1:3.3. The raffinate is then introduced into a second extraction column and contacted with water, the optional washing solvent c) according to the invention, in a water to raffinate mass ratio of 0.72:1. A separate oil phase (the final "raffinate product") and a separate solvent phase containing NMP and primarily water (the "extract") are produced. The other solvent phase from the second extraction column is used as demixing solvent b) and as a source of water added to each of the following decantation steps.

Water is added to the first solvent phase at a first solvent to water mass ratio of 50:1 [ie 2% water], the water being the demixing solvent b) according to the invention. After mixing and phase separation (by decantation), a first oil phase and a second solvent phase (comprising NMP and water) are produced. Additional water is then added to the second solvent phase at a second solvent to water mass ratio of 67:1 [ie, 1.5% water]. After mixing and phase separation (by decantation), a second oil phase and a third solvent phase are produced. Additional water is then added to the third solvent phase at a third solvent to water mass ratio of 4.6:1 [ie, 18% water]. After mixing and phase separation (by decantation), a third oil phase and a fourth solvent phase are produced.

Table 1 shows the flow rates (in parts by weight) of the first solvent phase and each of the first, second, and third oil phases based on the flow rate of the waste plastic oil feed. Since the ratio of the flow rate of the first solvent phase to the flow rate of the waste plastic oil feed is greater than 2:1, this means that the compounds are extracted from the waste plastic oil feed into the solvent. Table 1 also shows the relative amounts of various components in the first solvent phase and each of the first, second, and third oil phases based on the amount of that component in the waste plastic oil feed ( i.e. w.of% = "weight of feed").

As seen in Table 1, the first and second oil phases advantageously contain relatively small amounts of organic chloride (i.e., 6% by weight compared to 19.9% by weight in the third oil phase). Cl - total amount of aromatics of only .3% by weight) and a relatively small amount of aromatics containing no heteroatoms (i.e. 9.6% by weight compared to 14.5% by weight in the third oil phase) % other aromatics and only 22.2% by weight of polycyclic aromatics, compared to 42.1% by weight in the third oil phase; This may make these first and second oil phases suitable for recycling back to the process feed, for example. Alternatively, these first and second oil phases may be mixed with the final raffinate product described above, due to the low levels of heteroatom-containing contaminants, which are acceptable for such mixing. can be further reduced to a possible level. However, preferably these first and second oil phases are obtained by a first extraction with NMP before being introduced into the second extraction column, taking into account the presence of NMP in the oil phases. It may alternatively be mixed with the above raffinate (see Table 2 below). Advantageously, in the case of these blends, the first and second oil phases constitute an approximately 11% increase in oil recovery relative to the fresh feed (i.e., additional, combined based on feedstock). Flow of part 10.8).

Additionally, Table 2 lists the waste plastic oil feed, the first solvent phase, and the first, second, and third oil phases based on the amounts of the feeds or phases in question (i.e., w/w %). The relative amounts of the components in each are shown.

In Table 3 below, the above components selected in the process simulation in Aspen Plus V11 are further specified.

Claims (11)

A process for recovering aliphatic hydrocarbons from a liquid hydrocarbon feed stream comprising aliphatic hydrocarbons, heteroatom-containing organic compounds, and optionally aromatic hydrocarbons, the process comprising:
a) contacting at least a portion of said liquid hydrocarbon feed stream with an extraction solvent a) containing one or more heteroatoms, said liquid hydrocarbon feed stream being subjected to a liquid-liquid process with said extraction solvent a); Subjected to extraction to obtain a first stream comprising aliphatic hydrocarbons and a second stream comprising extraction solvent a), aliphatic hydrocarbons, heteroatom-containing organic compounds and optionally aromatic hydrocarbons. step and
b1) at least a portion of said second stream obtained from step a) is miscible in heptane containing one or more heteroatoms and having a miscibility lower than that of extraction solvent a) in heptane; and the resulting mixture is mixed with a first stream comprising aliphatic hydrocarbons and optionally aromatic hydrocarbons, extraction solvent a), demixing solvent b), hetero separating into a second stream comprising an atom-containing organic compound and optionally an aromatic hydrocarbon;
b2) mixing at least a portion of the second stream obtained from step b1) with a demixing solvent b), said resulting mixture comprising a heteroatom-containing organic compound and optionally an aromatic hydrocarbon; separating into a first stream and a second stream comprising extraction solvent a) and demixing solvent b);
(steps b1) and b2) are substeps of step b) comprising two or more substeps;
c) separating at least a portion of said second stream obtained from step b2) into a first stream comprising demixing solvent b) and a second stream comprising extraction solvent a);
d) recycling at least a portion of said extraction solvent a) from said second stream obtained from step c) to step a);
e) optionally recycling at least a portion of said demixing solvent b) from said first stream obtained from step c) to one or more of said substeps of step b). and a process including. Process according to claim 1, wherein step b) comprises 2 to 10, preferably 2 to 5 substeps. Step b) is
bi) mixing at least a portion of said second stream obtained from step a) with a demixing solvent b), said resulting mixture comprising aliphatic hydrocarbons and optionally aromatic hydrocarbons; separating into a first stream and a second stream comprising extraction solvent a), demixing solvent b), aliphatic hydrocarbons, heteroatom-containing organic compounds, and optionally aromatic hydrocarbons;
bii) mixing at least a portion of said second stream obtained from step bi) with a demixing solvent b) and combining said resulting mixture with aliphatic hydrocarbons, heteroatom-containing organic compounds, and optionally separating into a first stream comprising an aromatic hydrocarbon and a second stream comprising an extraction solvent a), a demixing solvent b), a heteroatom-containing organic compound, and optionally an aromatic hydrocarbon; ,
biii) mixing at least a portion of said second stream obtained from step bii) with a demixing solvent b), said resulting mixture being treated with a heteroatom-containing organic compound and optionally an aromatic hydrocarbon; separating into a first stream comprising an extraction solvent a) and a second stream comprising an extraction solvent b);
Step c) separates at least a portion of said second stream obtained from step biii) into a first stream comprising demixing solvent b) and a second stream comprising extraction solvent a). 3. The process according to claim 1 or 2, comprising: said extraction solvent a) has an R a of at least 5 MPa ^1/2 , preferably at least 10 MPa ^1/2 _{, heptane, and said demixing solvent b) has an R a} of at least 20 MPa ^1/2 , preferably at least 30 MPa ^1/2 of R _{a , heptane} , where R _{a , heptane} refers to the Hansen solubility parameter distance for heptane determined at 25°C;
R _{a for said demixing solvent b), heptane,} is greater than said R a for extraction solvent a), _heptane , and said difference in R _{a for solvents a) and b), heptane} is at least 1 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 . Said extraction solvent a) is ammonia or preferably diols and triols (including any isomers of monoethylene glycol (MEG), monopropylene glycol (MPG), butanediol and glycerol); glycol ethers (diethylene glycol, triols); (including ethylene glycol and tetraethylene glycol, including oligoethylene glycol), and their monoalkyl ethers (including diethylene glycol ethyl ether); amides (including N-alkylpyrrolidone, in which the alkyl group has 1 to 8 or 1 to 3 carbon atoms, including N-methylpyrrolidone (NMP)), formamide, and di- and monoalkylformamides, and acetamide (wherein the alkyl group contains 1 to 8 or 1 to 3 dialkyl sulfoxides (the alkyl group may contain 1 to 8 or 1 to 3 carbon atoms); , dimethyl sulfoxide (DMSO)); sulfones (including sulfolane); N-formylmorpholine (NFM); furan ring-containing components and their derivatives (furfural, 2-methylfuran, furfuryl alcohol and tetrahydrofurfuryl alcohol); hydroxy esters (including methyl lactate and ethyl lactate, including lactate); trialkyl phosphates (including triethyl phosphate); phenolic 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); Carbonic compounds ( and cycloalkanone compounds (including dihydrol evoglucosenone); Process described. said demixing solvent b) comprises one or more solvents selected from the group consisting of water and said solvent from the group of solvents defined for extraction solvent a) in claim 5; The process according to any one of claims 1 to 5, wherein preferably comprises water. Washing solvent c) is added to step a) to separate the first stream comprising the aliphatic hydrocarbons and washing solvent c), extraction solvent a), heteroatom-containing organic compound, and optionally aromatic hydrocarbons. or said first stream obtained from step a) comprises an aliphatic hydrocarbon and an extraction solvent a) and at least a portion of said first stream is washed. a first stream comprising aliphatic hydrocarbons and a second stream comprising washing solvent c) and extraction solvent a) by contacting with solvent c) and subjecting to liquid-liquid extraction with said washing solvent c). Process according to any one of claims 1 to 6, for obtaining. Process according to claim 7, wherein the washing solvent c) is the same or different, preferably the same, as the demixing solvent b) and preferably comprises water. A process for recovering aliphatic hydrocarbons from plastics, wherein at least a portion of the plastics comprises a heteroatom-containing organic compound;
(I) decomposing the plastic and recovering hydrocarbon products including aliphatic hydrocarbons, heteroatom-containing organic compounds, and optionally aromatic hydrocarbons;
(II) subjecting a liquid hydrocarbon feed stream comprising at least a portion of the hydrocarbon product obtained in step (I) to a process according to any one of claims 1 to 8; process, including. 10. A process for steam cracking a hydrocarbon feed, said hydrocarbon feed comprising aliphatic hydrocarbons as recovered in a process according to any one of claims 1 to 9. . A process for steam cracking a hydrocarbon feed, the process comprising:
A process according to any one of claims 1 to 9, comprising recovering aliphatic hydrocarbons from a liquid hydrocarbon feed stream;
steam cracking a hydrocarbon feedstock comprising aliphatic hydrocarbons recovered in the preceding step.

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