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

Abstract

The invention relates to a method for decontaminating a petrochemical composition, comprising the steps of: (i) subjecting a hydrocarbon composition (A) comprising an inorganic and / or polar contaminant to a water washing treatment, preferably wherein the inorganic and / or polar contaminant is a chlorine-containing contaminant, to obtain a washed product (B); and (ii) subjecting the product (B) obtained from step (i) to a nitrogen gas bubbling treatment to obtain a product (C). Such methods allow for the purification of hydrocarbon compositions, such as pyrolysis oil products obtained from the processing of waste plastic compositions, such that such hydrocarbon compositions may 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 wide variety of chemical conversion methods operate. These methods are highly optimized in terms of productivity, efficiency, and sustainability to achieve economical and profitable operation and high-quality products. One specific aspect related to this optimized production is the use of high-quality feedstocks (also known as feedstocks) as input materials.

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

[0004] Currently, the most desirable type of feedstock for use in the chemical and refining industries is that whose source can be found in the waste stream. The use of such feedstocks would greatly benefit the recycling of materials; it is highly desirable to use waste as a valuable feedstock for new methods. Of particular great interest is the use of materials derived from waste plastics as feedstocks. This would be very 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 majority of the atoms. Therefore, such materials have an atomic composition very similar to that of typical hydrocarbon materials conventionally used in the petrochemical and refining industries. Thus, materials derived from waste plastics may be well-suited for use in this industry.

[0005] In recent years, technological development and industrial activity have increased in the field of converting waste plastic materials into feed streams suitable for use in the petrochemical and refining industries. For example, waste plastic materials, which are solid at room temperature, can be converted into hydrocarbon-containing feed streams via technologies such as the pyrolysis of plastic materials. These hydrocarbon-containing feed streams are liquid at such temperatures and can therefore be processed in chemical and refining methods equipped with methods for converting liquid hydrocarbons. The product obtained from the pyrolysis of waste plastic materials can be referred to as plastic-derived oil.

[0006] Typical examples of such methods include those for the production of light olefins and aromatic compounds. Light olefins (e.g., ethylene and propylene) and aromatic compounds (e.g., benzene) are well-known and valuable building blocks widely used in the synthesis of chemical products, particularly polymer products (the most abundant examples being polyethylene and polypropylene).

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

[0008] Therefore, when a feed stream derived from waste plastics is used in such a cracking operation, polymer materials can be produced from waste polymer materials, thereby establishing the recycling of polymers. This understandably provides an attractive material synthesis route.

[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 significant losses in process efficiency occur in terms of equipment downtime and defective products when process interruptions occur. Furthermore, cracking is a highly sensitive process; conditions must be maintained within strict specifications. This also affects the feed materials that can be processed in these types of equipment.

[0010] On the other hand, the waste plastic streams available for processing are typically not very consistent in their composition; when they originate from waste collection operations (whether consumer-grade or industrial-grade), considerable variation in the composition of such streams can be expected between different batches. This can conflict with the requirements of chemical processing operations in which they can be used as feedstock, which stipulate a high level of consistency.

[0011] Therefore, it is necessary to ensure that products derived from waste plastics and used as feedstock in chemical operations such as cracking processes are appropriately consistent in composition and sufficiently pure.

[0012] One specific component that may be present in petrochemical feedstock compositions (such as streams derived from waste plastics, for example, plastic-derived oils) is chlorine. In petrochemical and refining operations, it is often desirable to process feedstocks containing particularly low levels of chlorine. Therefore, technologies capable of purifying petrochemical compositions such as plastic-derived oils to remove chlorine are desired. Summary of the Invention

[0013] This has now been achieved according to the present invention by a method for decontamination using a petrochemical composition, the method comprising the following steps:

[0014] (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

[0015] (ii) subject the product (B) obtained in step (i) to nitrogen bubbling treatment to obtain product (C).

[0016] Such a method allows for the purification of hydrocarbon compositions (e.g., pyrolysis oil products obtained from the processing of waste plastic compositions), making such hydrocarbon compositions suitable for processing in petrochemical and / or refining operations.

[0017] Hydrocarbon composition A can be, for example, a hydrocarbon-containing oil product obtained by decomposing waste plastics.

[0018] According to the present invention, the hydrocarbon composition A used herein may be defined, for example, by its boiling point range. This hydrocarbon composition is typically a product of hydrocarbon properties 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 have a typical boiling point range including an initial boiling point ≥25°C and a final boiling point ≤350°C. This boiling point may be determined according to the method specified in ASTM D86 (2012).

[0019] The initial boiling point reflects the lowest temperature at which a compound boils in a hydrocarbon-oil mixture, and is therefore an indicator of the temperature at which the most volatile compound (typically the lowest molecular weight compound) begins to boil under atmospheric pressure. The final boiling point reflects the highest temperature achievable in the boiling of a hydrocarbon-oil composition, and is therefore an indicator of the temperature at which the compound with the highest boiling point (typically the highest molecular weight compound) will also boil under atmospheric conditions.

[0020] Preferably, the hydrocarbon composition A used herein has an initial boiling point of ≥30°C, more preferably ≥50°C. Even more preferably, the 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, a 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.

[0021] Compositions with this 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.

[0022] 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 aromatic compounds. This 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 aromatic compounds.

[0023] In the context of this invention, the n-alkanes present in composition A may, for example, include n-alkanes having 3-40 carbon atoms. The iso-alkanes present in composition A may, for example, have 3-40 carbon atoms. The cycloalkanes present in composition A may, for example, have 3-40 carbon atoms. The aromatic compounds present in composition A may, for example, have 6-40 carbon atoms.

[0024] Hydrocarbon composition A may, for example, contain ≥25.0 and ≤95.0 wt% of n-chain alkanes relative to the total weight of hydrocarbon composition A. Preferably, hydrocarbon composition A contains ≥25.0 and ≤80.0 wt%, more preferably ≥25.0 and ≤70.0 wt%, and even more preferably ≥25.0 and ≤50.0 wt% of n-chain alkanes.

[0025] Hydrocarbon composition A may, for example, contain ≥5.0 and ≤40.0 wt% of isoparaffins relative to the total weight of hydrocarbon stream A. Preferably, hydrocarbon composition A contains ≥5.0 and ≤30.0 wt%, more preferably ≥7.5 wt% and ≤25.0 wt% of isoparaffins.

[0026] Hydrocarbon composition A may, for example, contain ≤50.0 wt% of olefins relative to the total weight of hydrocarbon composition A. Preferably, hydrocarbon composition A contains ≤40.0 wt%, more preferably ≤35.0 wt%, and even more preferably ≤30.0 wt% of olefins.

[0027] Hydrocarbon composition A may, for example, contain ≥5.0 and ≤50.0 wt% of olefins relative to the total weight of hydrocarbon composition A. Preferably, hydrocarbon composition A contains ≥10.0 and ≤40.0 wt%, more preferably ≥15.0 and ≤35.0 wt% of olefins.

[0028] Hydrocarbon composition A may, for example, contain ≥5.0 and ≤20.0 wt% of cycloalkanes relative to the total weight of hydrocarbon composition A. Preferably, hydrocarbon composition A contains ≥5.0 and ≤15.0 wt%, more preferably ≥7.5 wt% and ≤15.0 wt% of cycloalkanes.

[0029] Hydrocarbon composition A may, for example, contain ≥5.0 and ≤15.0 wt% of an aromatic compound relative to the total weight of hydrocarbon composition A. Preferably, hydrocarbon composition A contains ≥5.0 and ≤12.5 wt%, more preferably ≥7.5 wt% and ≤12.5 wt% of an aromatic compound.

[0030] Hydrocarbon composition A may, for example, comprise:

[0031] ≥25.0 and ≤95.0 wt%, preferably ≥25.0 and ≤70.0 wt%, more preferably ≥25.0 and ≤50.0 wt% of n-chain alkanes; and / or

[0032] ≥5.0 and ≤20.0 wt%, preferably ≥5.0 and ≤15.0 wt%, more preferably ≥7.5 and ≤15.0 wt% of isoparaffins; and / or

[0033] ≥5.0 and ≤50.0 wt%, preferably ≥10.0 and ≤40.0 wt%, more preferably ≥15.0 and ≤35.0 wt%, even more preferably ≥15.0 and ≤25.0 wt% of olefins; and / or

[0034] ≥5.0 and ≤20.0 wt%, preferably ≥5.0 and ≤15.0 wt%, more preferably ≥7.5 and ≤15.0 wt% of cycloalkanes; and / or

[0035] ≥5.0 and ≤15.0 wt%, preferably ≥5.0 and ≤12.5 wt%, more preferably ≥7.5 and ≤12.5 wt% of aromatic compounds;

[0036] Relative to the total weight of hydrocarbon composition A.

[0037] In the context of this invention, atomic chlorine content is understood to be the total weight of chlorine atoms present in the molecules of the hydrocarbon composition, expressed as a fraction of the total weight of the hydrocarbon stream. Atomic nitrogen content is understood to be the total weight of nitrogen atoms present in the molecules of the hydrocarbon stream, expressed as a fraction of the total weight of the hydrocarbon stream.

[0038] Hydrocarbon composition A may, for example, contain a certain amount of contaminants. For example, hydrocarbon composition A may contain a certain amount of compounds containing chlorine atoms. The amount of compounds 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 <800 ppm by weight, preferably <700 ppm, more preferably <600 ppm, even more preferably <500 ppm, even more preferably <400 ppm, as determined according to ASTM UOP 779-08.

[0039] Hydrocarbon composition A may, for example, contain >150 ppm, preferably >200 ppm, more preferably >250 ppm of atomic chlorine.

[0040] 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.

[0041] 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, 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 as determined according to ASTM D4629 (2017).

[0042] Hydrocarbon composition A may contain a certain amount of a compound comprising olefinic unsaturation. The amount of olefinic unsaturation is indicated by the bromine value of the hydrocarbon stream. The bromine value represents the amount (g) of bromine reacting with 100g of hydrocarbon sample when tested under the conditions of ASTM D1159-07 (2012). For example, hydrocarbon composition A used as in the method of the present invention may have a bromine value of <100, preferably <95, more preferably <90, and even more preferably <85.

[0043] Product C preferably contains <100ppm, more preferably <75ppm, even more preferably <50ppm, and even more preferably <25ppm of atomic chlorine.

[0044] Hydrocarbon composition A can be obtained, for example, by processing a stream of waste plastic feed. For instance, hydrocarbon composition A can be obtained by processing a stream of waste plastic in a pyrolysis unit.

[0045] Such a pyrolysis unit can be a continuously operating unit, wherein a stream of waste plastic is continuously supplied to the unit and a liquid stream containing pyrolysis products is continuously obtained from the unit. Alternatively, the pyrolysis unit can be used in batches, 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.

[0046] The pyrolysis process carried out in the pyrolysis unit can be a low-severity pyrolysis process or a high-severity pyrolysis process. In a low-severity pyrolysis process, pyrolysis can be carried out at a temperature of ≥250°C and ≤450°C, preferably ≥275°C and ≤425°C, and more preferably ≥300°C and ≤400°C. Alternatively, the pyrolysis process can be a high-severity process carried out at a temperature of ≥450°C and ≤750°C, preferably ≥500°C and ≤700°C, and more preferably ≥550°C and ≤650°C.

[0047] The pyrolysis process can be a catalytic process. In such a pyrolysis process, for example, a certain amount of zeolite catalyst, such as ZSM-5 zeolite catalyst, can be used. In such a pyrolysis process, for example, a certain amount of spent FCC catalyst can be used. Specifically, 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 between 0.5 and 5.0, for example, between 1.0 and 3.0.

[0048] The method of the present invention may include, for example, a pyrolysis step of the waste plastic composition prior to step (i), wherein the hydrocarbon composition A is obtained in the form of a liquid product from the pyrolysis.

[0049] The waste plastic feed used to produce hydrocarbon composition A in this method may, for example, contain polyolefins, polyesters, thermoplastic elastomers, polyvinyl chloride, polystyrene, or polycarbonate.

[0050] The waste plastic feedstock that can be used to produce hydrocarbon composition A can be a mixture comprising polyolefins, polyesters, thermoplastic elastomers, polyvinyl chloride, polystyrene, or polycarbonate. Specifically, the waste plastic feedstock that can be used to produce hydrocarbon composition A can be a mixture comprising >25.0 wt% polyolefins relative to the total weight of the waste plastic feedstock. Preferably, the waste plastic feedstock may comprise >40.0 wt%, more preferably >50.0 wt%, even more preferably >60.0 wt% or >70.0 wt% polyolefins. The waste plastic feedstock may contain a portion 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 feedstock comprising up to 10 wt%, preferably up to 5.0 wt%, more preferably up to 2.0 wt% of materials selected from paper, sand, and soil, and combinations thereof, can be used in methods for preparing polypropylene. This allows these feedstocks to be processed without the need for cleaning processes that may require the use of solvents or detergents.

[0051] For example, the waste plastic feed may contain ≤10.0 wt% of the following components: the sum of the contents of glass, paper, metal, cardboard, compostable waste, wood, stone, textiles, rubber materials and superabsorbent hygiene products, relative to the total weight of the waste plastic feed.

[0052] The waste plastic feed may, for example, contain ≥90.0 wt% polymer material relative to the total weight of the waste plastic feed.

[0053] The waste plastic feed may, for example, contain a certain amount of polyester. For instance, the waste plastic feed may contain <20.0 wt%, preferably <15.0 wt%, more preferably <10.0 wt%, even more preferably <5.0 wt%, and even more preferably <2.0 wt% polyester. In some embodiments, the waste plastic feed may not contain polyester.

[0054] For example, a typical type of polyester that may be present in the waste plastic feed used in the preparation of hydrocarbon stream A in this method is polyethylene terephthalate, also known as PET. This waste plastic feed may, for example, contain a certain amount of PET. For instance, the waste plastic feed may contain <20.0 wt%, preferably <15.0 wt%, more preferably <10.0 wt%, even more preferably <5.0 wt%, and even more preferably <2.0 wt% of PET. In some embodiments, the waste plastic feed may be PET-free.

[0055] Polyesters such as PET contain oxygen atoms in their polymer chains. The presence of compounds containing oxygen atoms in hydrocarbon stream A is limited because excessive oxygen atoms in the compounds supplied to the thermal cracking furnace can lead to problems in downstream processing of the cracked hydrocarbon stream D leaving the furnace, including scaling and corrosion. Therefore, it is desirable to control or even minimize the amount of oxygen-containing polymers in the waste plastic feed used to prepare hydrocarbon stream A.

[0056] The waste plastic feed may, for example, contain a certain amount of polyamide. For instance, the waste plastic feed may contain <20.0 wt%, preferably <15.0 wt%, more preferably <10.0 wt%, even more preferably <5.0 wt%, and even more preferably <2.0 wt% of polyamide. In some embodiments, the waste plastic feed may be polyamide-free.

[0057] For example, the specific types of polyamides typically present in the waste plastic feed used in the preparation of hydrocarbon stream A in this method are polyamide 6 and polyamide 6,6, which can also be referred to as PA6 and PA66, respectively. The waste plastic feed may, for example, contain a certain amount of PA6 or PA66. For instance, the waste plastic feed may contain <20.0 wt%, preferably <15.0 wt%, more preferably <10.0 wt%, even more preferably <5.0 wt%, and even more preferably <2.0 wt% of a total amount of PA6 and PA66. In some embodiments, the waste plastic feed may be free of PA6 and / or PA66.

[0058] The waste plastic feed may, for example, contain a certain amount of polyvinyl chloride, which may also be referred to as PVC. For example, the waste plastic feed may contain <5.0 wt%, preferably <2.0 wt%, more preferably <1.0 wt%, even more preferably <0.5 wt%, and even more preferably <0.1 wt% of PVC. In some embodiments, the waste plastic feed may be PVC-free.

[0059] The waste plastic feed may, for example, contain...

[0060] <20.0 wt%, preferably <10.0 wt%, of polyester; and / or

[0061] <20.0 wt%, preferably <10.0 wt%, of polyamide; and / or

[0062] <2.0wt%, preferably <1.0wt%, of polyvinyl chloride.

[0063] Relative to the total weight of polymer materials in the waste plastic feed.

[0064] The percentages of polyester, polyamide, and PVC in the waste plastic feed should be understood as the weight percentage of the total weight of the polymer materials present in the waste plastic feed.

[0065] The waste plastic feed may further contain a certain amount of moisture, for example, the waste plastic feed may contain up to 20.0 wt%, preferably up to 10.0 wt%, more preferably up to 5.0 wt%.

[0066] 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, preferably ≥10°C and ≤40°C, and more preferably ≥15°C and ≤30°C.

[0067] Preferably, the washing process includes subjecting the composition containing the hydrocarbon composition and water (preferably deionized water) to a mixing operation. In the washing step (i), the weight ratio of 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. The use of a small amount of water is desirable because it reduces the amount of wastewater. This mixing operation can be carried out by stirring for a period of ≥5 minutes, preferably ≥5 and ≤60 minutes.

[0068] 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.

[0069] The product of step (i) is then subjected to a nitrogen bubbling step (ii). A certain amount of the washed product B in liquid form may be supplied to the container. A certain volume of nitrogen may be supplied through the liquid washed product B, preferably under stirring, and the gas escaping from the liquid may subsequently be discharged from the container.

[0070] The nitrogen bubbling step can be carried out, for example, at a pressure of <500 kPa, preferably <200 kPa, and more preferably at atmospheric pressure. Nitrogen can be supplied to the container, for example, at a volumetric flow rate of >1.0 and <20 l / min, preferably >5.0 and <15.0 l / min per liter of washed product B. The nitrogen bubbling can be carried out for a period of >1 hour, preferably >2 hours, and more preferably >2 and <5 hours.

[0071] Subsequently, a vented gas containing volatile contaminants removed from the washed product B and nitrogen may be supplied to a condenser container to condense the volatile contaminants. The condenser container may operate, for example, at a temperature of <10°C, preferably <0°C, or even more preferably >-20°C and <0°C.

[0072] Step (ii) can be performed at a temperature of ≥10°C and ≤60°C, preferably ≥10°C and ≤40°C, more preferably ≥15°C and ≤30°C. Detailed Implementation

[0073] The invention will now be described through the following non-limiting embodiments.

[0074] For the purpose of disclosing the present invention, a plastic-derived oil product having an initial boiling point of 30°C and a final boiling point of 180°C is used as hydrocarbon feed stream A. This 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. This plastic-derived oil contains 43 wt% n-alkanes, 17 wt% isoalkanes, 19 wt% olefins, 10 wt% cycloalkanes, and 11 wt% aromatic compounds. This plastic-derived oil has a concentration of approximately 750 kg / m³. 3 The density.

[0075] Experiment 1: Water washing of the plastic-derived oil

[0076] The washing step was performed by supplying 100 ml of the plastic-derived oil and 100 ml of deionized water to a separatory funnel of suitable size 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 revealed that, as a result of the water washing step, 57.9 wt% of chlorine was removed from the plastic-derived oil.

[0077] Experiment 2: Adsorption of chlorine from the plastic-derived oil.

[0078] The plastic-derived oil was subjected to a nitrogen bubbling purification step. 150 ml of water-washed oil was added to a round-bottom flask. The nitrogen purification step was carried out at room temperature and atmospheric pressure. A nitrogen stream was introduced into the flask with the flask stirred at 350 rpm, so that the nitrogen was introduced into the liquid plastic-derived oil towards the bottom of the flask. Nitrogen escaping from the surface of the plastic-derived oil was expelled from the flask and fed into a condenser container cooled to -3°C, thereby removing volatile contaminants from the nitrogen stream. Nitrogen was supplied to the round-bottom flask at a volumetric flow rate of 1.5 L / min for a period of 180 minutes.

[0079] Purification of plastic-derived oil by nitrogen bubbling according to the method described above resulted in a 72.8 wt% reduction in chlorine content.

[0080] Experiment 3: Combination of water washing and nitrogen bubbling

[0081] In addition to the experiments described above, an experiment combining water washing and nitrogen bubbling was also conducted. Specifically, the oil product collected from Experiment 1 was further subjected to nitrogen bubbling according to the method described in Experiment 2. This resulted in the removal of 97.0 wt% of chlorine from the oil product obtained after this second decontamination step, compared to the original chlorine content of the plastic-derived oil.

[0082] Therefore, by applying a combination of water washing and nitrogen bubbling, more than 95 wt% of chlorine was removed from the plastic-derived oil sample.

Claims

1. A method for decontaminating petrochemical compositions, the method comprising the following steps: (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 (ii) subject the product (B) obtained in step (i) to nitrogen bubbling treatment to obtain product (C).

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

3. The method according to any one of claims 1-2, wherein the hydrocarbon composition A contains >200 ppm and <600 ppm of atomic chlorine as determined according to ASTM UOP 779-08.

4. The method according to any one of claims 1-3, wherein the hydrocarbon composition A comprises: ≥25.0 and ≤95.0 wt%, preferably ≥25.0 and ≤70.0 wt%, more preferably ≥25.0 and ≤50.0 wt% of n-chain alkanes; and / or ≥5.0 and ≤20.0 wt%, preferably ≥5.0 and ≤15.0 wt%, more preferably ≥7.5 and ≤15.0 wt% of isoparaffins; and / or ≥5.0 and ≤50.0 wt%, preferably ≥10.0 and ≤40.0 wt%, more preferably ≥15.0 and ≤35.0 wt%, even more preferably ≥15.0 and ≤25.0 wt% of olefins; and / or ≥5.0 and ≤20.0 wt%, preferably ≥5.0 and ≤15.0 wt%, more preferably ≥7.5 and ≤15.0 wt% of cycloalkanes; and / or Aromatic compounds comprising ≥5.0 and ≤15.0 wt%, preferably ≥5.0 and ≤12.5 wt%, and more preferably ≥7.5 and ≤12.5 wt%. Relative to the total weight of hydrocarbon composition A.

5. The method according to any one of claims 1-4, wherein the water washing treatment is performed at a temperature of ≥10°C and ≤60°C.

6. The method according to any one of claims 1-5, wherein the water washing treatment comprises subjecting the composition comprising the hydrocarbon composition and water, preferably deionized water, to a mixing operation.

7. The method according to any one of claims 1-6, wherein in the water washing step (i), the weight ratio of hydrocarbon composition A to water is 10:1 to 1:

10.

8. The method according to any one of claims 6-7, wherein the mixing operation is carried out by stirring for a period of time of ≥5 minutes, preferably ≥5 minutes and ≤60 minutes.

9. The method according to claims 6-8, 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.

10. The method according to any one of claims 1-9, wherein step (ii) comprises passing a volume of nitrogen gas through a liquid, a washed amount of product B, in a container under stirring, and discharging the gas escaping from the liquid.

11. The method of claim 10, wherein step (ii) is performed at a temperature ≥10°C and ≤60°C.

12. The method according to any one of claims 10-11, wherein nitrogen is supplied for a period of time of >1 hour, preferably >2 hours and <5 hours, at a volumetric flow rate of >5.0 and <15.0 l / min per liter of washed product B.

13. The method according to any one of claims 1-12, wherein the method comprises a pyrolysis step of the waste plastic composition prior to step (i), wherein the hydrocarbon composition A is obtained in the form of a liquid product from the pyrolysis.

14. The method according to claim 13, wherein the pyrolysis is carried out as a low-severity pyrolysis process at a temperature of ≥250°C and ≤450°C, preferably ≥275°C and ≤425°C, more preferably ≥300°C and ≤400°C; or as a high-severity pyrolysis process at a temperature of ≥450°C and ≤750°C, preferably ≥500°C and ≤700°C, more preferably ≥550°C and ≤650°C.

15. The method according to any one of claims 13-14, wherein the waste plastic composition comprises >40.0 wt%, more preferably >50.0 wt%, even more preferably >60.0 wt% or >70.0 wt% of polyolefin.