Process for decontaminating petrochemical compositions obtained from chemical recycling of polymeric materials

Abstract

The method of the invention comprises subjecting a hydrocarbon composition A to a liquid-liquid extraction step in an extraction vessel, wherein an aprotic or protic solvent is used as the extraction medium. The use of such a method allows for the purification of hydrocarbon compositions, in particular with respect to the content of chlorine-containing compounds. Such a chlorine content reduction is desirable for processing hydrocarbon compositions in a number of different chemical processing operations, such as steam cracking operations. The presence of higher levels of chlorine-containing compounds may lead to equipment corrosion in such methods, which may lead to, for example, equipment failure and / or time reduction between equipment maintenance intervals.

Description

Technical Field

[0001] This invention relates to a method for decontaminating petrochemical compositions. Background Technology

[0002] In the chemical and refining industries, a series of chemical transformation processes are operated. These processes are highly optimized in terms of productivity, efficiency, and sustainability to achieve economical and profitable operations and high-quality products. A specific aspect of such optimized production lies in the use of high-quality raw materials, also known as feedstocks, as input materials.

[0003] Many of these chemical and refining methods utilize petrochemical compositions as raw materials.

[0004] Currently, the type of feedstock particularly sought for use in the chemical and refining industries is one whose source is found in waste streams. Using such feedstocks would greatly benefit the recycling of materials; there is a strong desire to utilize waste materials as valuable raw materials for new methods. In particular, there is great interest in using materials derived from waste plastics as feedstocks. This is quite desirable in the petrochemical and refining industries because waste plastics are primarily streams of materials containing a large proportion of molecules, in which carbon and hydrogen constitute the dominant atomic proportion. Therefore, the atomic composition of such materials is very similar to that of typical hydrocarbon materials conventionally used in the petrochemical and refining industries. Thus, materials produced from waste plastics are well-suited for this industry.

[0005] In recent years, technological advancements and industrial activity have increased in the field of converting waste plastic materials into feedstock streams suitable for the petrochemical and refining industries. For example, through technologies such as the pyrolysis of plastic materials, waste plastic materials, which are solid at room temperature, can be converted into hydrocarbon-containing streams that are liquid at such temperatures, and can therefore be processed in chemical and refining methods equipped for converting liquid hydrocarbons. Such products obtained from the pyrolysis of waste plastic materials can be referred to as plastic-derived oils.

[0006] Typical examples of such methods include those for the production of light olefins and aromatics. Light olefins such as ethylene and propylene, and aromatics such as benzene, are well-known valuable building blocks, widely used in the synthesis of chemical products, especially polymer products, with polyethylene and polypropylene being the most abundant examples.

[0007] The most widely used method for producing light olefins and aromatics is the so-called cracking operation, typically thermal or catalytic cracking. In such a cracking operation, hydrocarbon molecules present in the feed stream (typically exhibiting fossil hydrocarbon characteristics) are subjected to conditions that cause atomic bonds to break and form smaller molecules. Due to the chemical reaction kinetics, such methods typically result in product compositions containing desired high-quality light olefins and aromatics. After leaving the cracking unit, the product composition is usually subjected to one or more separation operations to obtain a high-quality, high-purity chemical stream, which can be processed into desired final products, such as polymer materials.

[0008] Therefore, when a feed stream derived from waste plastics is used in such a cracking operation, polymeric materials can be produced from waste polymeric materials, thus establishing the recycling of polymers. It will be understood that this presents an attractive pathway for materials synthesis.

[0009] For waste plastic materials to be suitable for processing in chemical operations such as thermal or catalytic cracking, the product must meet very stringent material specifications. Cracking operations are commercially conducted on a global scale, and when process interruptions occur, significant losses in process efficiency occur in terms of plant downtime and defective products. Furthermore, cracking is a highly sensitive process. Conditions must be maintained within strict specifications. This also affects the feedstock materials that can be processed in such facilities.

[0010] On the other hand, waste plastic streams available for processing are typically not very consistent in their composition; as they emerge from waste collection operations, both at the consumer and industrial levels, considerable variation in composition can be expected from batch to batch. This conflicts with the requirements of chemical processing operations, where they can serve as raw materials, which demand a high level of consistency.

[0011] Therefore, it is necessary to ensure that products derived from waste plastics and which can be used as feedstocks in chemical or refining operations such as cracking are appropriately consistent in composition and sufficiently pure.

[0012] Chlorine is a specific component that can be present in petrochemical feedstock compositions, such as oils derived from waste plastics. In petrochemical and refining operations, it is generally desirable to process feedstocks containing particularly low levels of chlorine. Therefore, a technology is desired to purify petrochemical compositions, such as oils derived from plastics, to remove chlorine. Summary of the Invention

[0013] The present invention relates to a method for removing chlorinated compounds from hydrocarbon compositions, particularly from liquid hydrocarbon compositions.

[0014] Such liquid hydrocarbon compositions can be, for example, pyrolysis oil. In the context of this invention, pyrolysis oil is a product obtained from a method in which waste plastics are subjected to pyrolysis conditions, wherein the plastics are decomposed into products in the hydrocarbon oil range; in other words, the plastics are subjected to conditions that cause the chemical bonds in their polymer chains to break, producing products with lower molecular weights.

[0015] In the method of the present invention, the hydrocarbon composition is subjected to multiple chemical unit operations to reduce the content of chlorinated compounds that may be present therein.

[0016] The method of the present invention includes subjecting hydrocarbon composition A to a liquid-liquid extraction step in an extraction vessel, wherein an aprotic or protic solvent is used as the extraction medium.

[0017] In one specific embodiment, the present invention relates to a method comprising subjecting a hydrocarbon composition A to:

[0018] (a) A first liquid-liquid extraction step in a first extraction vessel (1), wherein an aprotic solvent is used as the extraction medium; and

[0019] (b) A second liquid-liquid extraction step in the second extraction vessel (2), wherein a proton solvent is used as the extraction medium.

[0020] Steps (a)-(b) can be applied in any order.

[0021] In a preferred embodiment, the method of the present invention includes the following steps:

[0022] (a) subjecting hydrocarbon composition A to a first liquid-liquid extraction step in a first extraction vessel (1), wherein an aprotic solvent is used as the extraction medium, to obtain composition E; and

[0023] (b) subjecting composition E to a second liquid-liquid extraction step in a second extraction vessel (2), wherein a protic solvent is used as the extraction medium to obtain hydrocarbon composition F.

[0024] Another embodiment of the present invention relates to a method of the present invention, the method comprising the following steps:

[0025] (a) subjecting hydrocarbon composition A to a first liquid-liquid extraction step in a first extraction vessel (1), wherein a protic solvent is used as the extraction medium, to obtain composition E; and

[0026] (b) subjecting composition E to a second liquid-liquid extraction step in a second extraction vessel (2), wherein an aprotic solvent is used as the extraction medium to obtain hydrocarbon composition F.

[0027] Applying such a method allows for the purification of hydrocarbon compositions, particularly regarding the content of chlorine-containing compounds. Such a reduction in chlorine content is desirable for processing hydrocarbon compositions in many different chemical processing operations, such as steam cracking. The presence of higher chlorine-containing compound content can lead to corrosion of equipment in such methods, which may result in, for example, equipment failures and / or shorter intervals between equipment maintenance. Given its significant impact on the economics of the method, it is clearly desirable to reduce the presence of chlorine-containing compounds to any extent possible. Attached Figure Description

[0028] exist Figure 1 The illustrations of some embodiments of the present invention are provided. Figure 1 middle:

[0029] A: Hydrocarbon composition A;

[0030] E: Composition E obtained from the first extraction step (a);

[0031] F: Hydrocarbon composition F obtained from the second extraction step (b);

[0032] 1: First extraction container

[0033] 2: Second extraction container

[0034] Hydrocarbon Composition A

[0035] Hydrocarbon composition A can be, for example, a hydrocarbon-containing oil product obtained by the decomposition of waste plastics.

[0036] According to the present invention, hydrocarbon composition A, as used herein, can be defined, for example, by its boiling point range. The hydrocarbon composition is typically a product of hydrocarbon characteristics and is typically a mixture of compounds with different boiling points. For processing in process operations typically used in the chemical and refining industries, the composition may be neither too viscous nor too volatile in composition. Typical boiling point ranges for suitable compositions may include an initial boiling point ≥25°C and a final boiling point ≤500°C, or ≤400°C, or ≤350°C. The boiling point can be determined according to the method described in ASTM D86 (2012).

[0037] The initial boiling point reflects the lowest temperature at which compounds in a hydrocarbon-oil mixture begin to boil; therefore, it is an indicator of the temperature at which the most volatile compounds, typically the lowest molecular weight compounds, begin to boil under atmospheric pressure. The terminal boiling point reflects the highest temperature that the hydrocarbon-oil composition can reach when boiling; thus, it indicates the temperature at which the highest boiling point compounds, typically the highest molecular weight compounds, boil again under atmospheric conditions.

[0038] Preferably, hydrocarbon composition A used in this invention has an initial boiling point of ≥30°C, more preferably ≥50°C. It is also preferred that hydrocarbon composition A has a final boiling point of ≤325°C, more preferably ≤300°C, even more preferably ≤250°C, even more preferably ≤225°C, or even ≤200°C. In particular, suitable hydrocarbon composition A may have an initial boiling point of ≥30°C and a final boiling point of ≤300°C, more preferably ≥30°C and a final boiling point of ≤250°C, even more preferably ≥50°C and a final boiling point of ≤200°C.

[0039] Compositions with such a range of initial and final boiling points are considered suitable for processing in chemical and refining operations, including allowing the application of appropriate transport, heating, cooling, and separation processes without undesirable process interruptions.

[0040] Furthermore, hydrocarbon composition A, which may be considered suitable for use in this invention, may, for example, contain a certain amount of n-alkanes, a certain amount of isoalkanes, a certain amount of olefins, a certain amount of cycloalkanes, and / or a certain amount of aromatics. The composition may, for example, contain a certain amount of n-alkanes, a certain amount of isoalkanes, a certain amount of olefins, a certain amount of cycloalkanes, and a certain amount of aromatics.

[0041] In the context of this invention, the n-alkanes that may be present in composition A may, for example, include n-alkanes having 3 to 40 carbon atoms. The isoalkanes that may be present in composition A may, for example, have 3 to 40 carbon atoms. The cycloalkanes that may be present in composition A may, for example, have 3 to 40 carbon atoms. The aromatics that may be present in hydrocarbon composition A may, for example, have 6 to 40 carbon atoms.

[0042] Relative to the total weight of hydrocarbon composition A, hydrocarbon composition A may, for example, contain ≥25.0 and ≤95.0% by weight of n-alkanes. Preferably, hydrocarbon composition A contains ≥25.0 and ≤80.0% by weight, more preferably ≥25.0 and ≤70.0% by weight, and even more preferably ≥25.0 and ≤50.0% by weight of n-alkanes.

[0043] Relative to the total weight percentage of hydrocarbon stream A, hydrocarbon composition A may, for example, contain ≥5.0 and ≤40.0% by weight of isoalkanes. Preferably, hydrocarbon composition A contains ≥5.0 and ≤30.0% by weight, more preferably ≥7.5% by weight and ≤25.0% by weight of isoalkanes.

[0044] Relative to the total weight of hydrocarbon composition A, hydrocarbon composition A may, for example, contain ≤50.0% by weight of olefins. Preferably, hydrocarbon composition A contains ≤40.0% by weight, more preferably ≤35.0% by weight, and even more preferably ≤30.0% by weight of olefins.

[0045] Relative to the total weight of hydrocarbon composition A, hydrocarbon composition A may, for example, contain ≥5.0 and ≤50.0% by weight of olefins. Preferably, hydrocarbon composition A contains ≥10.0 and ≤40.0% by weight, more preferably ≥15.0 and ≤35.0% by weight of olefins.

[0046] Relative to the total weight of hydrocarbon composition A, hydrocarbon composition A may, for example, contain ≥5.0 and ≤20.0% by weight of cycloalkanes. Preferably, hydrocarbon composition A contains ≥5.0 and ≤15.0% by weight, more preferably ≥7.5% by weight and ≤15.0% by weight of cycloalkanes.

[0047] Relative to the total weight of hydrocarbon composition A, hydrocarbon composition A may, for example, contain ≥5.0 and ≤15.0% by weight of aromatics. Preferably, hydrocarbon composition A contains ≥5.0 and ≤12.5% ​​by weight, more preferably ≥7.5% by weight and ≤12.5% ​​by weight of aromatics.

[0048] Relative to the total weight of hydrocarbon composition A, hydrocarbon composition A may, for example, comprise:

[0049] ≥25.0 and ≤95.0% by weight, preferably ≥25.0 and ≤70.0% by weight, more preferably ≥25.0 and ≤50.0% by weight of n-alkanes; and / or

[0050] ≥5.0 and ≤20.0% by weight, preferably ≥5.0 and ≤15.0% by weight, more preferably ≥7.5 and ≤15.0% by weight of isoalkanes; and / or

[0051] ≥5.0 and ≤50.0% by weight, preferably ≥10.0 and ≤40.0% by weight, more preferably ≥15.0 and ≤35.0% by weight, even more preferably ≥15.0 and ≤25.0% by weight of olefins; and / or

[0052] ≥5.0 and ≤20.0% by weight, preferably ≥5.0 and ≤15.0% by weight, more preferably ≥7.5 and ≤15.0% by weight of cycloalkanes; and / or

[0053] ≥5.0 and ≤15.0% by weight, preferably ≥5.0 and ≤12.5% ​​by weight, more preferably ≥7.5 and ≤12.5% ​​by weight of aromatics.

[0054] In the context of this invention, atomic chlorine content should be understood as the fraction of the total weight of chlorine atoms present in the molecules of the hydrocarbon composition to the total weight of the hydrocarbon stream. Atomic nitrogen content should be understood as the fraction of the total weight of nitrogen atoms present in the molecules of the hydrocarbon stream to the total weight of the hydrocarbon stream.

[0055] Hydrocarbon composition A may, for example, contain a certain amount of contaminants. For example, hydrocarbon composition A may contain a certain amount of a compound containing chlorine atoms. The amount of the compound containing chlorine atoms can be expressed as the atomic chlorine content of hydrocarbon stream A. For example, hydrocarbon composition A may have an atomic chlorine content of 2000 ppm, or <1500 ppm, or <1000 ppm, preferably <800 ppm, more preferably <700 ppm, more preferably <600 ppm, even more preferably <500 ppm, even more preferably <400 ppm, by weight, as determined according to ASTM UOP 779-08.

[0056] Hydrocarbon composition A may, for example, contain >150 ppm, preferably >200 ppm, more preferably >250 ppm of atomic chlorine.

[0057] For example, hydrocarbon composition A may contain >200 and <800 ppm, preferably >200 and <600 ppm, more preferably >200 and <500 ppm of atomic chlorine.

[0058] Hydrocarbon composition A may contain a certain amount of a compound containing nitrogen atoms. The amount of the compound containing nitrogen atoms may be expressed as the atomic nitrogen content of hydrocarbon composition A. For example, hydrocarbon composition A may have an atomic nitrogen content of <1600 ppm by weight, preferably <1500 ppm, more preferably <1400 ppm, even more preferably <1300 ppm, even more preferably <1200 ppm, or <1100 ppm, or <1000 ppm, as determined according to ASTM D5762 (2012). For example, hydrocarbon composition A may have an atomic nitrogen content of <100 ppm by weight, as determined according to ASTM D4629 (2017).

[0059] Hydrocarbon composition A may contain a certain amount of a compound with olefinic unsaturation. The amount of olefinic unsaturation is indicated by the bromine value of the hydrocarbon stream. The bromine value indicates the amount of bromine, in grams, reacted with 100 g of a hydrocarbon sample when tested under the conditions of ASTM D1159-07 (2012). For example, hydrocarbon composition A used in the method of the present invention may have a bromine value of <100, preferably <95, more preferably <90, and even more preferably <85.

[0060] Product C preferably contains <100ppm, more preferably <75ppm, even more preferably <50ppm, and even more preferably <25ppm of atomic chlorine.

[0061] Hydrocarbon composition A can be, for example, a stream of material obtained by processing waste plastic feedstock. For instance, hydrocarbon composition A can be obtained by processing a waste plastic stream in a pyrolysis unit.

[0062] Such a pyrolysis unit can be a continuous operation unit, wherein a stream of waste plastic is continuously supplied to the unit, and a liquid stream containing pyrolysis products is obtained from the unit at least continuously. Alternatively, the pyrolysis unit can be a batch operation unit, wherein a certain amount of waste plastic is introduced into the unit, subjected to pyrolysis conditions, and subsequently a liquid stream containing pyrolysis products is obtained from the unit at least.

[0063] The pyrolysis method carried out in the pyrolysis unit can be a low-severity pyrolysis method or a high-severity pyrolysis method. In the low-severity pyrolysis method, pyrolysis can be carried out at a temperature of ≥250°C and ≤450°C, preferably ≥275°C and ≤425°C, more preferably ≥300°C and ≤400°C. Alternatively, the pyrolysis method can be a high-severity method carried out at a temperature of ≥450°C and ≤750°C, preferably ≥500°C and ≤700°C, more preferably ≥550°C and ≤650°C.

[0064] The pyrolysis method can be a catalytic method. In such a pyrolysis method, for example, a certain amount of zeolite catalyst, such as ZSM-5 zeolite catalyst, can be used. In such a pyrolysis method, for example, a certain amount of spent FCC catalyst can be used. In particular, a composition comprising a certain amount of ZSM-5 catalyst and a certain amount of spent FCC catalyst can be used. For example, a composition comprising a certain amount of ZSM-5 and a certain amount of spent FCC catalyst can be used, wherein the weight ratio of spent FCC catalyst to ZSM-5 catalyst is 0.5 to 5.0, for example, 1.0 to 3.0.

[0065] The method of the present invention may include, for example, a step of pyrolysis of the waste plastic composition prior to one or more extraction steps, wherein hydrocarbon composition A is obtained as a liquid product from the pyrolysis.

[0066] The waste plastic raw materials used in the production of hydrocarbon composition A in this method may include, for example, polyolefins, polyesters, thermoplastic elastomers, polyvinyl chloride, polystyrene, or polycarbonate.

[0067] The waste plastic raw material that can be used in the production of hydrocarbon composition A can be a mixture comprising polyolefins, polyesters, thermoplastic elastomers, polyvinyl chloride, polystyrene, or polycarbonate. Specifically, the waste plastic raw material that can be used in the production of hydrocarbon composition A can be a mixture comprising >25.0% by weight of polyolefins relative to the total weight of the waste plastic raw material. Preferably, the waste plastic raw material can contain >40.0% by weight, more preferably >50.0% by weight, and even more preferably >60.0% by weight or >70.0% by weight of polyolefins. The waste plastic raw material can contain a certain proportion of non-thermoplastic materials. Such non-thermoplastic materials can be, for example, hydrocarbon-based materials, such as rubber materials, but can also be materials including paper, sand, and soil. An advantage of the present invention is that waste plastic raw materials containing up to 10% by weight, preferably up to 5.0% by weight, more preferably up to 2.0% by weight of materials selected from paper, sand, and soil, and combinations thereof, can be used in the method for preparing polypropylene. This allows such raw materials to be processed without requiring cleaning processes that might require the use of solvents or detergents.

[0068] For example, relative to the total weight of waste plastic raw materials, waste plastic raw materials may contain ≤10.0% by weight of components, which is the sum of the contents of glass, paper, metal, cardboard, compostable waste, wood, stone, textiles, rubber materials and superabsorbent hygiene products.

[0069] Relative to the total weight of waste plastic materials, waste plastic materials may, for example, contain ≥90.0% by weight of polymer materials.

[0070] Waste plastic raw materials may, for example, contain a certain amount of polyester. For instance, waste plastic raw materials may contain <20.0% by weight, preferably <15.0% by weight, more preferably <10.0% by weight, even more preferably <5.0% by weight, and even more preferably <2.0% by weight of polyester. In some embodiments, the waste plastic raw materials may be polyester-free.

[0071] For example, the waste plastic raw material used in the preparation of hydrocarbon stream A in this method can typically contain polyethylene terephthalate (PET), a specific type of polyester. The waste plastic raw material may, for example, contain a certain amount of PET. For instance, the waste plastic raw material may contain <20.0% by weight, preferably <15.0% by weight, more preferably <10.0% by weight, even more preferably <5.0% by weight, and even more preferably <2.0% by weight of PET. In some embodiments, the waste plastic raw material may be PET-free.

[0072] Polyesters such as PET contain oxygen atoms in their polymer chains. The presence of compounds containing oxygen atoms in hydrocarbon stream A is somewhat limited because excessive oxygen atoms in the compounds supplied to the thermal cracking furnace can cause problems, including scaling and corrosion in downstream processing of the cracked hydrocarbon stream D leaving the thermal cracking furnace. Therefore, it is desirable to control or even minimize the amount of oxygen-containing polymers in the waste plastic feedstock used to prepare hydrocarbon stream A.

[0073] Waste plastic raw materials may, for example, contain a certain amount of polyamide. For instance, the waste plastic raw material may contain <20.0% by weight, preferably <15.0% by weight, more preferably <10.0% by weight, even more preferably <5.0% by weight, and even more preferably <2.0% by weight of polyamide. In some embodiments, the waste plastic raw material may be polyamide-free.

[0074] For example, the waste plastic raw materials used in the preparation of hydrocarbon stream A in this method typically contain polyamide 6 and polyamide 6,6, which can also be referred to as PA6 and PA66, respectively. The waste plastic raw materials may, for example, contain a certain amount of PA6 or PA66. For instance, the waste plastic raw materials may contain <20.0% by weight, preferably <15.0% by weight, more preferably <10.0% by weight, even more preferably <5.0% by weight, and even more preferably <2.0% by weight of the total amount of PA6 and PA66. In some embodiments, the waste plastic raw materials may be free of PA6 and / or PA66.

[0075] Waste plastic raw materials may, for example, contain a certain amount of polyvinyl chloride, which can also be referred to as PVC. For example, waste plastic raw materials may contain <5.0% by weight, preferably <2.0% by weight, more preferably <1.0% by weight, even more preferably <0.5% by weight, and even more preferably <0.1% by weight of PVC. In some embodiments, waste plastic raw materials may be PVC-free.

[0076] Relative to the total weight of polymer materials in waste plastic raw materials, waste plastic raw materials may, for example, contain

[0077] <20.0% by weight, preferably <10.0% by weight, of polyester; and / or

[0078] <20.0% by weight, preferably <10.0% by weight, of polyamide; and / or

[0079] <2.0% by weight, preferably <1.0% by weight of polyvinyl chloride.

[0080] The percentages of polyester, polyamide, and PVC in waste plastic raw materials should be understood as the weight percentage of the total weight of polymer materials present in the waste plastic raw materials.

[0081] Waste plastic raw materials may also contain a certain amount of moisture, for example, waste plastic raw materials may contain up to 20.0% by weight, preferably up to 10.0% by weight, more preferably up to 5.0% by weight of moisture.

[0082] Aproton extraction steps

[0083] The aprotic solvent may be selected, for example, from dimethyl sulfoxide, dimethylformamide, sulfolane, and N-methyl-2-pyrrolidone. Preferably, the aprotic solvent is selected from dimethyl sulfoxide and dimethylformamide.

[0084] The aprotic solvent can be applied, for example, in an amount relative to composition C such that the aprotic solvent accounts for ≥40.0 and ≤90.0% by volume of the contents of the first extraction container (1), preferably ≥50.0% by volume and ≤65.0% by volume, more preferably ≥55.0% by volume and ≤60.0% by volume.

[0085] The first extraction step (a) can be carried out, for example, at a temperature of >15°C and <60°C, preferably >20°C and <40°C.

[0086] The first extraction step (a) can be carried out, for example, at a pressure of >50 and <200 kPa, preferably >75 and <150 kPa, such as atmospheric pressure.

[0087] The first extraction step (a) can, for example, be performed for a time period of >1.0 and <75.0 minutes, preferably >1.0 and <30.0 minutes, more preferably >5.0 and <20.0 minutes, and even more preferably >5.0 and <15.0 minutes.

[0088] In a preferred embodiment, the first extraction step (a) uses ≥55.0% by volume and ≤60.0% by volume of dimethyl sulfoxide or dimethylformamide as a solvent in the contents of the first extraction container (1) for a period of >5.0 and <15.0 minutes at a temperature of >20°C and <40°C and a pressure of >75 and <150 kPa.

[0089] Proton extraction steps

[0090] The proton solvent can be selected, for example, from ethylene glycol, water, methanol, and ethanol. Preferably, the proton solvent is ethylene glycol.

[0091] The proton solvent can be applied, for example, in an amount relative to composition E such that the proton solvent accounts for ≥40.0 and ≤70.0% by volume of the contents of the second extraction container (2), preferably ≥50.0% by volume and ≤65.0% by volume, more preferably ≥55.0% by volume and ≤60.0% by volume.

[0092] The second extraction step (b) can be carried out, for example, at a temperature of >15°C and <60°C, preferably >20°C and <40°C.

[0093] The second extraction step (b) can be carried out, for example, at a pressure of >50 and <200 kPa, preferably >75 and <150 kPa, such as atmospheric pressure.

[0094] The second extraction step (b) can, for example, be performed for a time period of >1.0 and <75.0 minutes, preferably >1.0 and <30.0 minutes, more preferably >5.0 and <20.0 minutes, and even more preferably >5.0 and <15.0 minutes.

[0095] In a preferred embodiment, the second extraction step (b) uses ≥55.0% by volume and ≤60.0% by volume of ethylene glycol from the contents of the second extraction container (2) as a solvent, and is carried out at a temperature of >20°C and <40°C for a period of >5.0 and <15.0 minutes at a pressure of >75 and <150 kPa.

[0096] The method of the present invention is preferably a continuous operation method.

[0097] The invention will now be illustrated by the following non-limiting embodiments.

[0098] For the purposes of illustrating the present invention, a plastic-derived oil product with an initial boiling point of 30°C and a final boiling point of 180°C is used as hydrocarbon stream A. The plastic-derived oil product has a total chlorine content of approximately 350 ppm, a total nitrogen content of less than 1000 ppm, and a bromine value of less than 85. The plastic-derived oil contains 43 wt% n-alkanes, 17 wt% isoalkanes, 19 wt% olefins, 10 wt% cycloalkanes, and 11 wt% aromatics. The plastic-derived oil has a hydrocarbon content of approximately 750 kg / m³. 3 The density.

[0099] First extraction step

[0100] The plastic-derived oil disclosed above was supplied to a 100 ml penicillin bottle as an extraction container. A certain amount of solvent according to Table 2 below was added to fill 58% of the contents of the extraction container.

[0101] The first extraction step was carried out at 20°C and atmospheric pressure for 60 minutes. Samples were taken from the extraction experiment. The atomic chlorine content of the samples was determined, as shown in Table 2 below.

[0102] Table 2: First extraction in aprotic solvents

[0103]

[0104] Second extraction step

[0105] The product obtained from the first extraction step using dimethyl sulfoxide (containing 46 ppm atomic chlorine by weight) (Sample 1) was supplied to a 100 ml penicillin bottle as the extraction container. A certain amount of ethylene glycol was added as a proton solvent to fill 58% of the contents of the extraction container.

[0106] The second extraction step is carried out at 20°C and atmospheric pressure for 60 minutes.

[0107] Another sample 3 was obtained from this second extraction step. This resulted in a dechlorinated hydrocarbon product containing 39 ppm of atomic chlorine by weight.

Claims

1. A method comprising subjecting a hydrocarbon composition A to a liquid-liquid extraction step in an extraction vessel, wherein an aprotic or protic solvent is used as the extraction medium.

2. The method according to claim 1, wherein the method comprises subjecting hydrocarbon composition A to: (a) A first liquid-liquid extraction step in a first extraction vessel (1), wherein an aprotic solvent is used as the extraction medium; and (b) A second liquid-liquid extraction step in the second extraction vessel (2), wherein a proton solvent is used as the extraction medium. Steps (a)-(b) can be applied in any order.

3. The method according to any one of claims 1-2, the method comprising the following steps: (a) subjecting hydrocarbon composition A to a first liquid-liquid extraction step in a first extraction vessel (1), wherein an aprotic solvent is used as the extraction medium to obtain composition E; and (b) subjecting the composition E to a second liquid-liquid extraction step in a second extraction vessel (2), wherein a proton solvent is used as the extraction medium to obtain a hydrocarbon composition F.

4. The method according to any one of claims 1-2, the method comprising the following steps: (a) subjecting hydrocarbon composition A to a first liquid-liquid extraction step in a first extraction vessel (1), wherein a protic solvent is used as the extraction medium to obtain composition E; and (b) subjecting the composition E to a second liquid-liquid extraction step in a second extraction vessel (2), wherein an aprotic solvent is used as the extraction medium to obtain a hydrocarbon composition F.

5. The method according to any one of claims 1-4, wherein the hydrocarbon composition A is a hydrocarbon-containing oil product obtained by decomposing waste plastics.

6. The method according to any one of claims 1-5, wherein the hydrocarbon composition A comprises atomic chlorine at a concentration of >200 ppm and <2000 ppm by weight, preferably >200 ppm and <600 ppm, as determined by ASTM UOP779-08.

7. The method according to any one of claims 1-6, wherein, relative to the total weight of the hydrocarbon composition A, the hydrocarbon composition A comprises: ≥ 25.0 and ≤ 95.0% by weight, preferably ≥ 25.0 and ≤ 70.0% by weight, more preferably ≥ 25.0 and ≤ 50.0% by weight of n-alkanes; and / or ≥ 5.0 and ≤ 20.0% by weight, preferably ≥ 5.0 and ≤ 15.0% by weight, more preferably ≥ 7.5 and ≤ 15.0% by weight of isoalkanes; and / or ≥ 5.0 and ≤ 50.0% by weight, preferably ≥ 10.0 and ≤ 40.0% by weight, more preferably ≥ 15.0 and ≤ 35.0% by weight, even more preferably ≥ 15.0 and ≤ 25.0% by weight of olefins; and / or ≥ 5.0 and ≤ 20.0% by weight, preferably ≥ 5.0 and ≤ 15.0% by weight, more preferably ≥ 7.5 and ≤ 15.0% by weight of cycloalkanes; and / or ≥ 5.0 and ≤ 15.0% by weight, preferably ≥ 5.0 and ≤ 12.5% ​​by weight, more preferably ≥ 7.5 and ≤ 12.5% ​​by weight of aromatics.

8. The method according to any one of claims 1-7, wherein the aprotic solvent is selected from dimethyl sulfoxide, dimethylformamide, sulfolane and N-methyl-2-pyrrolidone, preferably selected from dimethyl sulfoxide and dimethylformamide.

9. The method according to any one of claims 1-8, wherein the aprotic solvent is applied in an amount relative to the composition in the container such that the aprotic solvent accounts for ≥40.0 and ≤70.0% by volume of the contents of the extraction container, preferably ≥50.0% by volume and ≤65.0% by volume, more preferably ≥55.0% by volume and ≤60.0% by volume.

10. The method according to any one of claims 2-9, wherein the first extraction step (a) uses ≥55.0 vol% and ≤60.0 vol% of dimethyl sulfoxide or dimethylformamide as a solvent in the contents of the extraction container (1) for a period of >5.0 and <15.0 minutes at a temperature of >20°C and <40°C and a pressure of >75 and <150 kPa.

11. The method according to any one of claims 1-10, wherein the proton solvent is selected from ethylene glycol and water.

12. The method according to any one of claims 1-11, wherein the proton solvent is applied in an amount relative to the composition in the container such that the proton solvent accounts for ≥40.0 and ≤70.0% by volume of the contents of the extraction container, preferably ≥50.0% by volume and ≤65.0% by volume, more preferably ≥55.0% by volume and ≤60.0% by volume.

13. The method according to any one of claims 1-12, wherein the second extraction step (b) uses ≥55.0 vol% and ≤60.0 vol% of ethylene glycol of the contents of the second extraction container (2) as a solvent, at a temperature >20°C and <40°C, and at a pressure >75 and <150 kPa for a time period of >5.0 and <15.0 minutes.

14. The method according to any one of claims 1-13, wherein the method includes a pyrolysis step of the waste plastic composition prior to undergoing one or more extraction steps, preferably wherein the waste plastic composition comprises >40.0% by weight, more preferably >50.0% by weight, even more preferably >60.0% by weight, or >70.0% by weight of polyolefin, wherein the hydrocarbon composition A is obtained as a liquid product from the pyrolysis.

15. The method according to claim 14, wherein the pyrolysis is performed using a low-severity pyrolysis method at a temperature ≥250°C and ≤450°C, preferably ≥275°C and ≤425°C, more preferably ≥300°C and ≤400°C; or using a high-severity pyrolysis method at a temperature ≥450°C and ≤750°C, preferably ≥500°C and ≤700°C, more preferably ≥550°C and ≤650°C.

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