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CN-122003485-A - Process for decontamination of petrochemical compositions obtained from chemical recycling of polymeric materials

CN122003485ACN 122003485 ACN122003485 ACN 122003485ACN-122003485-A

Abstract

The process of the present invention comprises subjecting the hydrocarbon composition a to a liquid-liquid extraction step in an extraction vessel, wherein an aprotic or protic solvent is used as extraction medium. The use of such a process allows for the purification of hydrocarbon compositions, in particular with respect to 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 operations. The presence of higher levels of chlorine-containing compounds may lead to equipment corrosion in such processes, which may lead to, for example, equipment failure and/or reduced time between equipment repair intervals.

Inventors

  • F. Cook
  • HUANG KAIXIN
  • A. C. Aka
  • R. Aresa

Assignees

  • SABIC环球技术有限责任公司
  • 沙特阿拉伯石油公司

Dates

Publication Date
20260508
Application Date
20241011
Priority Date
20231013

Claims (15)

  1. 1. A process 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 extraction medium.
  2. 2. The method of claim 1, comprising subjecting hydrocarbon composition a to: (a) A first liquid-liquid extraction step in a first extraction vessel (1) in which an aprotic solvent is used as the extraction medium, and (B) A second liquid-liquid extraction step in a second extraction vessel (2), wherein a protic solvent is used as extraction medium, Wherein steps (a) - (b) may be applied in any order.
  3. 3. The method according to any one of claims 1-2, comprising the steps of: (a) Subjecting the hydrocarbon composition A to a first liquid-liquid extraction step in a first extraction vessel (1) in which an aprotic solvent is used as extraction medium to obtain composition E, and (B) The composition E is subjected to a second liquid-liquid extraction step in a second extraction vessel (2), wherein a protic solvent is used as extraction medium to obtain a hydrocarbon composition F.
  4. 4. The method according to any one of claims 1-2, comprising the steps of: (a) Subjecting the hydrocarbon composition A to a first liquid-liquid extraction step in a first extraction vessel (1) in which a protic solvent is used as extraction medium to obtain composition E, and (B) The composition E is subjected to a second liquid-liquid extraction step in a second extraction vessel (2), wherein an aprotic solvent is used as extraction medium to obtain a hydrocarbon composition F.
  5. 5. The process according to any one of claims 1 to 4, wherein the hydrocarbon composition a is a hydrocarbon-containing oil product obtained by decomposition of waste plastics.
  6. 6. The method according to any one of claims 1-5, wherein the hydrocarbon composition a comprises > 200ppm and < 2000ppm, preferably > 200ppm and < 600ppm atomic chlorine by weight as determined according to ASTM UOP 779-08.
  7. 7. The method of any one of claims 1-6, wherein the hydrocarbon composition a comprises, relative to the total weight of the hydrocarbon composition a: 25.0% by weight or more and 95.0% by weight or less, preferably 25.0% by weight or more and 70.0% by weight or less, more preferably 25.0% by weight or more and 50.0% by weight or less, of normal paraffins, and/or Equal to or greater than 5.0 and equal to or less than 20.0 wt%, preferably equal to or greater than 5.0 and equal to or less than 15.0 wt%, more preferably equal to or greater than 7.5 and equal to or less than 15.0 wt% isoparaffin, and/or More preferably more than or equal to 5.0 and less than or equal to 50.0 wt%, more preferably more than or equal to 10.0 and less than or equal to 40.0 wt%, more preferably more than or equal to 15.0 and less than or equal to 35.0 wt%, more preferably more than or equal to 15.0 and less than or equal to 25.0 wt% of olefins, and/or More preferably more than or equal to 5.0 and less than or equal to 20.0 wt%, more preferably more than or equal to 5.0 and less than or equal to 15.0 wt%, more preferably more than or equal to 7.5 and less than or equal to 15.0 wt% of cycloalkanes, and/or Aromatic hydrocarbon of 5.0% by weight or more and 15.0% by weight or less, preferably 5.0% by weight or more and 12.5% by weight or less, more preferably 7.5% by weight or more and 12.5% by weight or less.
  8. 8. The process according to any one of claims 1-7, wherein the aprotic solvent is selected from the group consisting of dimethyl sulfoxide, dimethylformamide, sulfolane and N-methyl-2-pyrrolidone, preferably selected from the group consisting of dimethyl sulfoxide and dimethylformamide.
  9. 9. The method of any one of claims 1-8, wherein the aprotic solvent is applied in an amount relative to the composition in the vessel such that the aprotic solvent comprises ≡40.0 and ≡70.0% by volume, preferably ≡50.0% and ≡65.0% by volume, more preferably ≡55.0% and ≡60.0% by volume of the contents of the extraction vessel.
  10. 10. The method according to any one of claims 2-9, wherein the first extraction step (a) is performed using as solvent, dimethyl sulfoxide or dimethylformamide, at a temperature >20 ℃ and <40 ℃, at a pressure >75 and <150 kPa, for a period of time >5.0 and <15.0 minutes, of ≡55.0% and ≡60.0% by volume of the content of the extraction vessel (1).
  11. 11. The process according to any one of claims 1-10, wherein the protic solvent is selected from ethylene glycol and water.
  12. 12. The method of any one of claims 1-11, wherein the protic solvent is applied in an amount relative to the composition in the vessel such that the protic solvent comprises ≡40.0 and ≡70.0% by volume, preferably ≡50.0% and ≡65.0% by volume, more preferably ≡55.0% and ≡60.0% by volume of the contents of the extraction vessel.
  13. 13. The process according to any one of claims 1-12, wherein the second extraction step (b) is performed at a temperature of >20 ℃ and <40 ℃ at a pressure of >75 and <150 kPa for a period of >5.0 and <15.0 minutes using ≡55.0% and ≡60.0% by volume of ethylene glycol as solvent of the content of the second extraction vessel (2).
  14. 14. The process according to any one of claims 1-13, wherein the process comprises a step of pyrolysis of a waste plastic composition prior to being subjected to one or more extraction steps, preferably 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 a polyolefin, wherein hydrocarbon composition a is obtained as a liquid product from pyrolysis.
  15. 15. The process according to claim 14, wherein the pyrolysis is carried out in a low severity pyrolysis process at a temperature of > 250 ℃ and < 450 ℃, preferably > 275 ℃ and < 425 ℃, more preferably > 300 ℃ and < 400 ℃, or in a high severity pyrolysis process at a temperature of > 450 ℃ and < 750 ℃, preferably > 500 ℃ and < 700 ℃, more preferably > 550 ℃ and < 650 ℃.

Description

Process for decontamination of petrochemical compositions obtained from chemical recycling of polymeric materials Technical Field The present invention relates to a method for decontaminating petrochemical compositions. Background In the chemical and refinery industries, a series of chemical conversion processes are operated. These processes are highly optimized in terms of productivity, efficiency and sustainability to achieve economical and profitable operation and high quality products. A particular aspect with respect to such an optimized production consists in using high quality raw materials, also called raw materials, as input materials. Many such chemical and refinery processes utilize petrochemical compositions as feedstock. A particularly desirable type of feedstock currently sought for use in the chemical and refinery industries is one from which its source is found in the waste stream. The use of such materials would greatly facilitate the recycling of the materials, and it would be highly desirable to be able to utilize waste materials as valuable materials for the new process. In particular, there is a great interest in using materials derived from waste plastics as raw materials. This may be quite desirable in the petrochemical and refinery industries because waste plastics are predominantly material streams containing a large proportion of molecules in which carbon and hydrogen constitute the major proportion of atoms. Thus, the atomic composition of such materials is very similar to typical hydrocarbon materials conventionally used in the petrochemical and refinery industries. Therefore, materials produced from waste plastics are well suited for use in the industry. In recent years, there has been an increase in technical development and industrial activity in the field of converting waste plastic materials into a feed stream applicable to petrochemical and refinery industries. For example, waste plastic materials that are solid at room temperature can be converted to hydrocarbon-containing streams that are liquid at such temperatures by techniques such as pyrolysis of plastic materials, and thus can be processed in chemical and refinery processes equipped for converting liquid hydrocarbons. Such products obtained from pyrolysis of waste plastic materials may be referred to as plastic-derived oils. Typical examples of such processes include light olefin and aromatic hydrocarbon production processes. Light olefins such as ethylene and propylene and aromatics such as benzene are well known valuable building blocks that are commonly used in the synthesis of chemical products, particularly polymer products, the most abundant examples of which are polyethylene and polypropylene. The most widely used process for the production of light olefins and aromatics is the so-called cracking operation, typically a thermal or catalytic cracking operation. In such cracking operations, hydrocarbon molecules (which typically have fossil hydrocarbon properties) present in the raw material stream are subjected to conditions that break the atomic bonds and form smaller molecules. Due to the kinetics of chemical reactions, such processes typically result in a product composition comprising the desired high quality light olefins and aromatics. After leaving the cracking unit, the product composition is typically subjected to one or more separation operations to obtain a high quality, high purity chemical stream, which can be processed into the desired end product, e.g., into a polymeric material. Thus, when a feed stream derived from waste plastics is used in such cracking operations, polymeric material may be produced from the waste polymeric material and thus establish recycling of the polymer. It will be appreciated that this presents an attractive route for material synthesis. In order for waste plastic materials to be suitable for processing in chemical operations such as thermal or catalytic cracking operations, the product must meet very stringent material specifications. Cracking operations are performed commercially in world-scale operations and when process interruptions occur, significant loss of process efficiency occurs in terms of plant downtime and off-grade products. Furthermore, the cracking process is a very sensitive process. The conditions must be kept within strict specifications. This also has an effect on the feedstock materials that can be processed in such devices. On the other hand, waste plastic streams available for processing are typically not very consistent in terms of their composition, and as they emerge from waste collection operations, whether at the consumer or industrial level, the composition of such streams can be expected to vary considerably from one batch to the next. This can conflict with the requirements of chemical processing operations for which they can act as feedstock materials, requiring a high level of consistency. Thus, there is a need to ensure that products de