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

Abstract

The present invention relates to a decontaminating process for petrochemical compositions, said process comprising subjecting a hydrocarbon composition (A) comprising an inorganic and / or polar contaminant to the following steps: (i) a water washing treatment and (ii) an adsorption treatment, preferably wherein said inorganic and / or polar contaminant is a chlorine-containing contaminant. This process allows for the purification of hydrocarbon compositions, such as pyrolysis oil products obtained from the processing of waste plastic compositions, such that such hydrocarbon compositions can be suitable for processing in petrochemical and / or refinery operations.

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 that can be used as raw materials in chemical 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] According to the present invention, this is now achieved by a decontamination method for petrochemical compositions, the method comprising subjecting a hydrocarbon composition (A) containing inorganic and / or polar contaminants to the following steps:

[0014] (i) Water washing treatment, and

[0015] (ii) Adsorption treatment.

[0016] The inorganic and / or polar pollutants are preferably chlorine-containing pollutants.

[0017] In one embodiment, the method of the present invention includes the following steps:

[0018] (i) subjecting a hydrocarbon composition (A) containing inorganic and / or polar contaminants to water washing, preferably wherein the inorganic and / or polar contaminants are chlorine-containing contaminants, to obtain a washed product (B); and

[0019] (ii) subject the product (B) obtained in step (i) to adsorption treatment to obtain product (C).

[0020] This method allows for the purification of hydrocarbon compositions, such as pyrolysis oil products obtained from the processing of waste plastic compositions, making such hydrocarbon compositions suitable for processing in petrochemical and / or refining operations.

[0021] Hydrocarbon composition A can be, for example, a hydrocarbon-containing oil product obtained by the decomposition of waste plastics.

[0022] 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. A suitable composition may typically have a boiling point range of ≥25°C and a final boiling point ≤350°C. The boiling point can be determined according to the method described in ASTM D86 (2012).

[0023] 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.

[0024] 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.

[0025] 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.

[0026] 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.

[0027] 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.

[0028] 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.

[0029] 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.

[0030] 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.

[0031] 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.

[0032] 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.

[0033] 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.

[0034] Relative to the total weight of hydrocarbon composition A, hydrocarbon composition A may, for example, comprise:

[0035] ≥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

[0036] ≥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

[0037] ≥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

[0038] ≥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

[0039] ≥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.

[0040] 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.

[0041] 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.

[0042] Hydrocarbon composition A may, for example, contain >150 ppm, preferably >200 ppm, more preferably >250 ppm of atomic chlorine.

[0043] 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.

[0044] 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).

[0045] 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.

[0046] Product C preferably contains <100 ppm, more preferably <75 ppm of atomic chlorine.

[0047] 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.

[0048] 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.

[0049] 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.

[0050] 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.

[0051] The method of the present invention may include, for example, a step of pyrolysis of the waste plastic composition prior to step (i), wherein hydrocarbon composition A is obtained as a liquid product from the pyrolysis.

[0052] 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.

[0053] 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.

[0054] 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.

[0055] Relative to the total weight of waste plastic materials, waste plastic materials may, for example, contain ≥90.0% by weight of polymer materials.

[0056] 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.

[0057] 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.

[0058] 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.

[0059] 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.

[0060] 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.

[0061] 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.

[0062] Relative to the total weight of polymer materials in waste plastic raw materials, waste plastic raw materials may, for example, contain

[0063] <20.0% by weight, preferably <10.0% by weight, of polyester; and / or

[0064] <20.0% by weight, preferably <10.0% by weight, of polyamide; and / or

[0065] <2.0% by weight, preferably <1.0% by weight of polyvinyl chloride.

[0066] 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.

[0067] 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.

[0068] In the method of the present invention, the water washing step (i) is preferably carried out at a temperature of ≥10°C and ≤60°C, more preferably ≥10°C and ≤40°C, and more preferably ≥15°C and ≤30°C.

[0069] Preferably, the washing process includes subjecting the composition comprising the hydrocarbon composition and water, preferably deionized water, to a mixing operation. In the washing step (i), the weight ratio of the hydrocarbon composition A to water is 10:1 to 1:10, preferably 5:1 to 1:5, more preferably 3:1 to 1:3, and even more preferably 2:1 to 1:2. It is desirable to use a small amount of water, as this reduces the amount of wastewater. The mixing operation can be carried out, for example, by stirring for a period of ≥5 minutes, preferably ≥5 and ≤60 minutes.

[0070] Preferably, the mixing operation is followed by a settling period, during which phase separation occurs to obtain an aqueous phase and a washed product B.

[0071] In the method of the present invention, step (ii) may, for example, include supplying a certain amount of adsorbent to the washed product B. Preferably, the adsorbent is supplied in an amount of ≥1.0 and ≤10.0% by weight relative to the weight of the washed product B, more preferably ≥2.0 and ≤5.0% by weight.

[0072] The adsorbent can be selected, for example, from alumina, silica, and aluminosilicate adsorbents. For instance, the adsorbent can be a zeolite-type aluminosilicate adsorbent. Such zeolite-type adsorbents can be selected, for example, from FAU, BEA, MOR, MFI, and FER zeolites. In particular, the adsorbent can be BEA zeolite, also known as β-zeolite.

[0073] The adsorbent may be, for example, an aluminosilicate zeolite containing Fe, Ge, Ga, B, Zn, Sn, Ti, or Ce atoms in its structure. Preferably, the adsorbent is a zeolite containing Fe, Zn, or Ce atoms in its structure. Particularly preferably, the adsorbent is a zeolite containing Ce atoms in its structure. For example, the adsorbent may be a Ce-containing β-zeolite, an Fe-containing β-zeolite, or a Zn-containing β-zeolite. Preferably, the adsorbent may be a Ce-containing β-zeolite.

[0074] The adsorbent may, for example, have a concentration of >100 and <800 m. 2 / g, preferably >200 and <600m 2 / g BET surface area. The adsorbent may, for example, have an average pore diameter of >0.3 and <0.8 nm, preferably >0.5 and <0.8 nm.

[0075] The adsorbent may be, for example, an aluminosilicate having a Si to Al weight ratio of <3.0, preferably <2.0, more preferably >1.0 and <2.0.

[0076] In some embodiments, step (ii) may include a first step: mixing the washed product B with the adsorbent for a period of >0.5 and <10 hours, more preferably >2 and <6 hours, followed by a separation step, preferably by centrifugation, to remove the adsorbent and obtain product C.

[0077] Step (ii) can be carried out at a temperature of ≥10°C and ≤60°C, preferably ≥10°C and ≤40°C, more preferably ≥15°C and ≤30°C.

[0078] The invention will now be described by way of the following non-limiting embodiments.

[0079] 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.

[0080] Experiment 1: Washing with water containing oil derived from plastic

[0081] The washing step was performed by supplying 100 ml of plastic-derived oil and 100 ml of deionized water to a properly sized separation funnel at room temperature. The funnel was agitated for 20 minutes to form an emulsion. The emulsion was then allowed to settle for 30 minutes to allow phase separation. The oil and aqueous phases were removed separately from the funnel and characterized. Analysis of the resulting oil product showed that 57.9% by weight of chlorine was removed from the plastic-derived oil due to the water washing step.

[0082] Experiment 2: Adsorption of chlorine in plastic-derived oil.

[0083] The oil derived from plastics underwent an adsorption step. 30 ml of water-washed oil and 1 g of adsorbent were added to a round-bottom flask. The adsorption step was carried out at room temperature. Several adsorbents were tested, as shown in the table below:

[0084]

[0085] Adsorption experiments were conducted by stirring the flask at room temperature and atmospheric pressure for 5 hours. The contents of the flask were then transferred to centrifuge tubes and centrifuged at 6000 rpm for 10 minutes. The decontaminated plastic-derived oil was then collected and subjected to further chlorine content characterization; the results are shown in the table below.

[0086]

[0087] As can be observed, the highest efficiency was achieved using Ce-β zeolite adsorbent.

[0088] Experiment 3: Combination of washing and adsorption

[0089] In addition to the experiments described above, experiments combining water washing and adsorption were also conducted. Specifically, the oil product collected from Experiment 1 underwent an adsorption experiment according to the method described in Experiment 2, using Ce-β zeolite as the adsorbent. This resulted in an oil product obtained after this second decontamination step, in which 80.1% by weight of chlorine was removed compared to the original chlorine content of the plastic-derived oil.

[0090] Therefore, by applying a combination of water washing and adsorption, more than 80% by weight of chlorine was removed from the oil sample from the plastic source.

Claims

1. A method for decontaminating a petrochemical composition, the method comprising subjecting a hydrocarbon composition (A) containing inorganic and / or polar contaminants to the following steps: (i) Water washing treatment, and (ii) Adsorption treatment Preferably, the inorganic and / or polar contaminants are chlorine-containing contaminants.

2. The method according to claim 1, wherein the method comprises the following steps: (i) subjecting a hydrocarbon composition (A) containing inorganic and / or polar contaminants to water washing, preferably wherein said inorganic and / or polar contaminants are chlorine-containing contaminants, to obtain a washed product (B); and (ii) subject the product (B) obtained in step (i) to adsorption treatment to obtain product (C).

3. The method according to any one of claims 1-2, wherein the hydrocarbon composition A is a hydrocarbon-containing oil product obtained by decomposing waste plastics.

4. The method according to any one of claims 1-3, wherein the hydrocarbon composition A contains >200 ppm and <600 ppm of atomic chlorine as determined according to ASTM UOP779-08.

5. The method according to any one of claims 1-4, 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.

6. The method according to any one of claims 1-5, wherein the water washing treatment is performed at a temperature of ≥10°C and ≤60°C.

7. The method according to any one of claims 1-6, wherein the water washing treatment comprises subjecting the composition comprising the hydrocarbon composition and water, preferably deionized water, to a mixing operation.

8. The method according to any one of claims 1-7, wherein in the water washing step (i), the weight ratio of hydrocarbon composition A to water is 10:1 to 1:

10.

9. The method according to any one of claims 7-8, wherein the mixing operation is performed by stirring for a period of time of ≥5 minutes, preferably ≥5 minutes and ≤60 minutes.

10. The method according to claims 7-9, wherein the mixing operation is followed by a settling period, during which phase separation occurs to obtain an aqueous phase and a washed product B.

11. The method according to any one of claims 1-10, wherein step (ii) comprises supplying an amount of adsorbent to the washed product B, preferably wherein the adsorbent is supplied in an amount of ≥1.0 and ≤10.0% by weight relative to the weight of the washed product B.

12. The method according to claim 11, wherein the adsorbent is selected from alumina, silica and zeolite adsorbents, preferably β-zeolite containing Ce atoms.

13. The method according to any one of claims 11-12, wherein step (ii) comprises a first step: mixing the washed product B with the adsorbent, preferably for >0.5 and <10 hours, followed by a separation step, preferably by centrifugation, to remove the adsorbent and obtain the product C.

14. The method according to any one of claims 1-13, wherein the method comprises a step of pyrolysis of the waste plastic composition prior to step (i), 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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