System and method for rapid dump tank heating

{
  "publication_number": "US11578145B2",
  "country": "US",
  "kind": "B2",
  "title": "System and method for rapid dump tank heating",
  "abstract": "A method of operating a dump tank of a polymer production process by transferring all or a portion of a content of a polymerization reactor into the dump tank, wherein the reactor contents comprise solid polymer, and liquid and gaseous non-product components, and removing at least a portion of the liquid and gaseous non-product components from the dump tank by: reducing a pressure of the dump tank, subjecting the solid polymer to a first cleaning stage comprising heating the solid polymer by introducing a first heated treatment gas into the dump tank, and subjecting the solid polymer to a second cleaning stage comprising purging the solid polymer by introducing a second heated treatment gas into the dump tank.",
  "claims": [
    "1. A method of operating a dump tank of a polymer production process, the method comprising: transferring all or a portion of a content of a polymerization reactor into the dump tank, wherein the reactor contents comprise solid polymer, and liquid and gaseous non-product components; and removing at least a portion of the liquid and gaseous non-product components from the dump tank by: reducing a pressure of the dump tank, whereby a flash gas comprising a first portion of the at least a portion of the liquid and gaseous non-product components is recovered from the dump tank; subjecting the solid polymer to a first cleaning stage comprising heating the solid polymer by introducing a first heated treatment gas comprising primarily one or more hydrocarbons into the dump tank until a first cleaning stage temperature of the solid polymer is attained and recovering a first gas comprising at least a portion of the first heated treatment gas and a second portion of the at least a portion of the liquid and gaseous non-product components from the dump tank during the first cleaning stage; and removing a portion of the one or more hydrocarbons from the first gas to yield recovered hydrocarbons and a treated first gas, further comprising subjecting the solid polymer to a second cleaning stage comprising purging the solid polymer by introducing a second heated treatment gas comprising primarily nitrogen into the dump tank and recovering a second gas comprising a third portion of the at least a portion of the liquid and gaseous non-product components from the dump tank during the second cleaning stage.",
    "2. A method of operating a dump tank of a polymer production process, the method comprising: transferring all or a portion of a content of a polymerization reactor into the dump tank, wherein the reactor contents comprise solid polymer, and liquid and gaseous non-product components; and removing at least a portion of the liquid and gaseous non-product components from the dump tank by: reducing a pressure of the dump tank, whereby a flash gas comprising a first portion of the at least a portion of the liquid and gaseous non-product components is recovered from the dump tank; subjecting the solid polymer to a first cleaning stage comprising heating the solid polymer by introducing a first heated treatment gas comprising primarily one or more hydrocarbons into the dump tank until a first cleaning stage temperature of the solid polymer is attained and recovering a first gas comprising at least a portion of the first heated treatment gas and a second portion of the at least a portion of the liquid and gaseous non-product components from the dump tank during the first cleaning stage; and removing a portion of the one or more hydrocarbons from the first gas to yield recovered hydrocarbons and a treated first gas, further comprising recycling a portion of the recovered hydrocarbons to the polymerization reactor, the dump tank, or both and further comprising subjecting the solid polymer to a second cleaning stage comprising purging the solid polymer by introducing a second heated treatment gas comprising primarily nitrogen into the dump tank and recovering a second gas comprising a third portion of the at least a portion of the liquid and gaseous non-product components from the dump tank during the second cleaning stage.",
    "3. A method of operating a dump tank of a polymer production process, the method comprising: transferring all or a portion of a content of a polymerization reactor into the dump tank, wherein the reactor contents comprise solid polymer, and liquid and gaseous non-product components; and removing at least a portion of the liquid and gaseous non-product components from the dump tank by: reducing a pressure of the dump tank, whereby a flash gas comprising a first portion of the at least a portion of the liquid and gaseous non-product components is recovered from the dump tank; subjecting the solid polymer to a first cleaning stage comprising heating the solid polymer by introducing a first heated treatment gas comprising primarily one or more hydrocarbons into the dump tank until a first cleaning stage temperature of the solid polymer is attained and recovering a first gas comprising at least a portion of the first heated treatment gas and a second portion of the at least a portion of the liquid and gaseous non-product components from the dump tank during the first cleaning stage; and removing a portion of the one or more hydrocarbons from the first gas to yield recovered hydrocarbons and a treated first gas, further comprising recycling a portion of the recovered hydrocarbons to the polymerization reactor, the dump tank, or both, further comprising flaring at least a portion of the treated first gas, and further comprising subjecting the solid polymer to a second cleaning stage comprising purging the solid polymer by introducing a second heated treatment gas comprising primarily nitrogen into the dump tank and recovering a second gas comprising a third portion of the at least a portion of the liquid and gaseous non-product components from the dump tank during the second cleaning stage.",
    "4. The method of claim 1, further comprising removing a portion of the nitrogen from the second gas to yield recovered nitrogen and a treated second gas.",
    "5. The method of claim 2, further comprising removing a portion of the nitrogen from the second gas to yield recovered nitrogen and a treated second gas.",
    "6. The method of claim 3, further comprising removing a portion of the nitrogen from the second gas to yield recovered nitrogen and a treated second gas.",
    "7. The method of claim 4, further comprising recycling a portion of the recovered nitrogen to the dump tank.",
    "8. The method of claim 5, further comprising recycling a portion of the recovered nitrogen to the dump tank.",
    "9. The method of claim 6, further comprising recycling a portion of the recovered nitrogen to the dump tank.",
    "10. The method of claim 4, further comprising flaring at least a portion of the treated second gas.",
    "11. The method of claim 5, further comprising flaring at least a portion of the treated second gas.",
    "12. The method of claim 6, further comprising flaring at least a portion of the treated second gas.",
    "13. The method of claim 7, further comprising flaring at least a portion of the treated second gas.",
    "14. The method of claim 8, further comprising flaring at least a portion of the treated second gas.",
    "15. The method of claim 9, further comprising flaring at least a portion of the treated second gas.",
    "16. The method of claim 8, wherein the polymer production process comprises an isobutane nitrogen recovery unit (INRU), and wherein at least a portion of the nitrogen introduced into the dump tank via the second treatment gas comprises nitrogen recovered from the INRU.",
    "17. The method of claim 16, further comprising introducing the second gas into the INRU or another separation apparatus operable to separate nitrogen from the second gas.",
    "18. The method of claim 1, further comprising recycling a portion of the recovered hydrocarbons to the polymerization reactor, the dump tank, or both.",
    "19. The method of claim 1, further comprising flaring at least a portion of the treated first gas.",
    "20. The method of claim 2, further comprising flaring at least a portion of the treated first gas.",
    "21. The method of claim 18, further comprising flaring at least a portion of the treated first gas."
  ],
  "description_excerpt": "Not applicable.\n\nThe disclosed apparatus, systems, and methods relate to transferring (e.g., “dumping”) the contents or inventory of one or more polymerization reactors to a relief vessel (e.g., a “dump” tank). More specifically, the disclosed apparatus, systems, and methods relate to improved dump tanks and methods of removing non-product components from a polymerization reactor inventory comprising polymer fluff transferred to a dump tank during a polymerization reactor dump. Still more specifically, the disclosed apparatus, systems, and methods relate to improved methods of removing non-product components of a polymerization reactor inventory transferred to a dump tank during a polymerization reactor dump via cleaning of the polymer fluff by contact of the polymerization reactor inventory transferred to the dump tank with a first heated treatment gas comprising primarily hydrocarbons, followed by purging of the dump tank with a second heated treatment gas comprising primarily nitrogen.\n\nDuring certain atypical operating situations within a polymerization unit, such as, without limitation, loss of utilities (e.g., power), loss of steam, loss of a circulation pump/circulation pump seal, loss of reactor outlets, or any other significant event where continuing to circulate or have polymer in a polymerization reactor is undesirable, there is a need to quickly divert, drain or empty the polymerization reactor (e.g., to “dump” the contents or “inventory” of the polymerization reactor). Polymerization units are typically equipped with dump tanks for this purpose.",
  "cpc": [
    "C08F 2/008",
    "B01D 3/009",
    "B01D 3/06",
    "B01J 19/0053",
    "B01J 19/1837",
    "B01J 2204/002",
    "B01J 2204/005",
    "B01J 2204/007",
    "B01J 2208/00761",
    "B01J 2219/00092",
    "B01J 2219/00094",
    "B01J 4/001",
    "B01J 4/008",
    "B01J 8/0015",
    "C08F 10/00",
    "C08F 2/01",
    "C08F 6/005"
  ],
  "ipc": [
    "B01J 19/00",
    "B01J 19/18",
    "B01J 4/00",
    "C08F 2/00",
    "C08F 2/01",
    "C08F 6/00"
  ],
  "assignees": [
    "Chevron Phillips Chemical Co LP"
  ],
  "inventors": [
    "Joseph A. CURREN",
    "James E. Hein",
    "Ralph W. Romig",
    "Ai-fu Chang"
  ],
  "filing_date": "2021-05-07",
  "publication_date": "2023-02-14",
  "grant_date": "2023-02-14",
  "priority_date": "2019-05-06",
  "application_number": "US-202117314236-A",
  "family_id": "70775598",
  "cited_by_count": 2,
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    "CN207699496U",
    "WO2020227251A1"
  ]
}