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US-12624186-B2 - Chemical recycling of plastic purge materials

US12624186B2US 12624186 B2US12624186 B2US 12624186B2US-12624186-B2

Abstract

Processes and facilities for using one or more PET-containing materials as a feedstock to a chemical recycling facility, and in particular a solvolysis facility, are provided herein. The PET-containing materials used as feedstock may comprise a quantity of PET-containing solidified purge material. The PET-containing solidified purge material may be derived from various processes and facilities, including PET reclaimer facilities, manufacturers of PET articles, and/or a polymer manufacturing facilities. For example, the purge material may be the solidified purge material from an extrusion and/or pelletization process. Such solidified purge materials are generally undesirable or unusable to mechanical PET recycling facilities, and typically are sent to landfills and/or incinerators. However, the processes and facilities described herein make use of the PET and other plastics present in these otherwise undesirable or unusable solidified purge materials.

Inventors

  • Bruce Roger DeBruin
  • Michael Paul Ekart
  • Anne-Martine Sherbeck Jackson
  • Nathan Mitchell West
  • Zhufang Liu

Assignees

  • EASTMAN CHEMICAL COMPANY

Dates

Publication Date
20260512
Application Date
20210413

Claims (12)

  1. 1 . A method of recycling a plastic waste comprising: (a) feeding a quantity of PET-containing solidified purge material separated from said plastic waste to a chemical recycling facility; (b) reducing the size of said quantity of solidified purge material to form a quantity of plastic particulate solids before said depolymerization (c), wherein said reducing comprises a mechanical size reduction process and wherein said mechanical size reduction process comprises shredding, and said plastic particulate solids have a D90 particle size of less than 5.08 cm (2 inches); (c) depolymerizing in said chemical recycling facility at least a portion of said plastic particulate solids; wherein the feeding (a) comprises feeding said quantity of solidified purge material directly into a solvolysis facility within said chemical recycling facility, and wherein said solvolysis facility is a methanolysis facility that utilizes methanol as the principal solvent; and wherein the method comprises one or both of: (i) recovering a quantity of plastic fines produced from said shredding and having a D90 of less than 0.32 cm (1/8 inches), and densifying at least a portion of said plastic fines into plastic particles having a D90 particle size of 0.32 cm (1/8 inches) to 2.54 cm (1 inch) before depolymerizing (c); and/or (ii) recovering a quantity of large plastic particulates produced from said shredding and having a D90 of greater than 2.54 cm (1 inch), and shredding at least a portion of said large plastic particulates into plastic particles having a D90 particle size of 0.32 cm (1/8 inches) to 2.54 cm (1 inch) before depolymerizing (c).
  2. 2 . The method of claim 1 , wherein no grinder is used to reduce the size of said solidified purge material.
  3. 3 . The method of claim 1 , wherein said reducing produces a quantity of dry fines, strings, strands, and/or fibrous materials.
  4. 4 . The method of claim 3 , wherein said quantity of dry fines, strings, strands, and/or fibrous materials is recovered and densified into plastic particles having a D90 particle size of 0.32 cm (⅛ inches) to 2.54 cm (1 inch) before said depolymerizing (c).
  5. 5 . The method of claim 1 , wherein said quantity of solidified purge material comprises at least 90 weight percent PET on a dry basis.
  6. 6 . The method of claim 1 , wherein said quantity of solidified purge material comprises not more than 50 weight percent polyolefins.
  7. 7 . The method of claim 1 , wherein said quantity of solidified purge material comprises not more than 20 weight percent PVC.
  8. 8 . The method of claim 1 , wherein said quantity of solidified purge material comprises at least 0.1 weight percent co-polyesters on a dry basis.
  9. 9 . The method of claim 1 , wherein said quantity of solidified purge material comprises at least 95 weight percent of materials that are solid at the processing temperature of the molten polymer processing apparatus from which the quantity of solidified purge material is produced.
  10. 10 . The method of claim 9 , wherein said solid materials comprise glass, metals, and/or other fillers.
  11. 11 . The method of claim 1 , wherein said quantity of solidified purge material is produced by a PET reclaimer facility, a manufacturer of PET articles, and/or a polymer manufacturing facility.
  12. 12 . The method of claim 1 , wherein said quantity of solidified purge material comprises clear plastics and/or colored plastics.

Description

CROSS-REFERENCE TO RELATED APPLICATION(S) This application is a national stage filing under 35 USC § 371 of International Application Number PCT/US2021/026985, filed on Apr. 13, 2021 which claims the benefit of the filing date to U.S. Provisional Application No. 63/008,926, filed on Apr. 13, 2020, the entire disclosures of which are incorporated by reference herein. BACKGROUND Waste materials, especially non-biodegradable waste materials, can negatively impact the environment when disposed of in landfills after a single use. Thus, from an environmental standpoint, it is desirable to recycle as much waste material as possible. However, there still exist streams of low value waste that are nearly impossible or economically unfeasible to recycle with conventional recycling technologies. In addition, some conventional recycling processes produce waste streams that are themselves not economically feasible to recover or recycle, resulting in additional waste streams that must be disposed of or otherwise handled. For example, PET reclaimer facilities, manufacturers of PET articles, and/or polymer manufacturing facilities can produce significant amounts of waste plastics that are undesirable or unusable by consumers and mechanical recycling facilities. In particular, such facilities can produce quantities of solidified purge materials that are undesirable or unusable to mechanical recycling facilities in their extracted form, but may contain some amount of otherwise desirable or usable PET and/or other plastics. However, the solidified purge materials are typically disposed of in landfills and/or incinerators. Thus, a need exists for a large-scale facility capable of chemically recycling a variety of plastic-containing waste materials recovered from such sources, particularly otherwise undesirable or unusable PET-containing solidified purge materials from PET reclaimer facilities, manufacturers of PET articles, and/or polymer manufacturing facilities, in an economically viable manner. SUMMARY In one aspect, the present technology concerns a method of recycling a plastic waste. Generally, the method comprises: (a) feeding a quantity of PET-containing solidified purge material separated from the plastic waste to a chemical recycling facility; and (b) depolymerizing in the chemical recycling facility at least a portion of the PET-containing solidified purge material. In one aspect, the present technology concerns the use of PET-containing solidified purge material as a feedstock to a chemical recycling facility. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block flow diagram illustrating the main steps of a process and facility for chemically recycling waste plastic according to embodiments of the present technology; FIG. 2 is a block flow diagram illustrating a separation process and zone for separating mixed plastic waste according to embodiments of the present technology; FIG. 3 is a block flow diagram illustrating the main steps of a process and facility for PET solvolysis according to embodiments of the present technology; FIG. 4 is a block flow diagram illustrating typical rPET products and co-products derived from a PET reclaimer facility; FIG. 5 is a block flow diagram illustrating the main steps of a PET reclaimer process, and the resulting products and co-products produced therefrom; FIG. 6 is a block flow diagram illustrating an exemplary liquification zone of the chemical recycling facility shown in FIG. 1 according to embodiments of the present technology; FIG. 7 is a block flow diagram illustrating the main steps of a pyrolysis process and facility for converting waste plastic into a pyrolyzed product streams according to embodiments of the present technology; FIG. 8A is a block flow diagram illustrating the main steps of an integrated pyrolysis process and facility and a cracking process and facility according to embodiments of the present technology; FIG. 8B is a schematic diagram of a cracking furnace according to embodiments of the present technology; FIG. 9 is a schematic diagram of a POx reactor according to embodiments of the present technology; and FIG. 10 is a schematic diagram illustrating various definitions of the term “separation efficiency” as used herein. DETAILED DESCRIPTION We have discovered new methods and systems for using one or more PET-containing materials from various sources as a feedstock to a chemical recycling facility, and in particular a solvolysis facility. More particularly, we have discovered that PET-containing materials used as feedstock for chemical recycling or solvolysis may include PET-containing solidified purge materials that may be derived, for example, from PET reclaimer facilities, manufacturers of PET articles, and/or polymer manufacturing facilities. While these purge materials are generally considered undesirable or unusable by mechanical recycling facilities, they can contain some amount of recoverable and useful plastics, such as PET. The methods and syst