Reactor with vertical condensation tube and method for the polymerisation of polyamides in such a reactor

{
  "publication_number": "US9938375B2",
  "country": "US",
  "kind": "B2",
  "title": "Reactor with vertical condensation tube and method for the polymerisation of polyamides in such a reactor",
  "abstract": "The invention relates to a reactor in the form of a VK tube (VK: simplified continuous), for the polymerisation of polyamides, the reactor being subdivided into an upper and lower reactor region, which are controllable independently of each other. Likewise, the invention relates to a method for the production of polyamides in which such a reactor is used.",
  "claims": [
    "1. A reactor in the form of a simplified continuous (VK) tube for the polymerisation of polyamides with an upper and a lower reactor region, the upper reactor region having an inflow region for the addition of a prepolymer melt, a heating unit, a first flow tube part, a heated discharge cone, and over the entire height of the upper reactor region, an upper reactor region wall heater, and the lower reactor region having an inflow region for the addition of the melt from the upper reactor region and the separation of process vapour, a static cooling unit, a second flow tube part, a heated discharge cone and a discharge pipe connected thereto, and over the entire height of the lower reactor region, a lower reactor region wall heater, and the upper and the lower reactor regions being connected via a tube, wherein, between the discharge cone of the upper reactor region and the inflow region of the lower reactor region, a metering pump or a control valve for the transport of the prepolymer is integrated.",
    "2. The reactor according to claim 1, wherein the heating unit is a static heating unit, or a dynamic heating unit, and/or the static cooling unit is a tube bundle, an internally heated overflow body, a plate heat exchanger or a heating coil.",
    "3. The reactor according to claim 1, wherein an agitator is disposed above the heating unit.",
    "4. The reactor according to claim 1, wherein the VK tube is connected to a prepolymerisation reactor for the prepolymerisation of polyamides, the prepolymerisation reactor having an inflow region for the addition of educts, a heating unit, a first flow tube part which has a first wall heater, a second flow tube part which has a second wall heater and an outlet pipe for the prepolymer, and a cooling unit disposed between the first flow tube part and the second flow tube part.",
    "5. The reactor according to claim 4, wherein the cooling unit and the second wall heater of the prepolymerisation reactor are coupled thermally via a single heat-transfer medium circulation.",
    "6. The reactor according to claim 1, wherein the lower reactor region wall heater and the upper reactor region wall heater, independently of each other, are double jackets and/or half-pipe heating coils.",
    "7. The reactor according to claim 1, wherein the flow tube parts have, at least partially, flow rectifiers.",
    "8. A method for the polymerisation of polyamides in a reactor according to claim 1 in the form of a vertical condensation tube (VK tube) with an upper and a lower reactor region, in which a) a prepolymer melt is metered into the inflow region of the upper reactor region, b) the temperature of the melt is set to 240 to 280° C. by means of the heating unit of the upper reactor region, c) the melt is conducted via the first flow tube part, which is coupled to the upper reactor region wall heater in order to avoid a heat loss, to the static cooling unit with which the temperature of the melt is set to 225 to 260° C. and d) the melt is transported via the second flow tube part, which is coupled to the lower reactor region wall heater in order to avoid a heat loss, to an outlet pipe.",
    "9. The method according to claim 8, wherein the prepolymer melt is supplied from a prepolymerisation reactor wherein a) educts are metered into an inflow region of the prepolymerisation reactor, b) the metered educts are heated to form a prepolymer melt and the temperature of the prepolymer melt is set to 240 to 270° C. by means of a heating unit in an upper region of the prepolymerisation reactor, c) the resulting prepolymer melt is conducted via a first flow tube part, which is coupled to a separate wall heating unit in order to avoid a heat loss, to a cooling unit with which the temperature of the prepolymer melt is set to 220 to 255° C., and d) the resulting prepolymer melt is transported via a second flow tube part, which is coupled to a separate wall heating unit in order to avoid a heat loss, to an outlet tube which is coupled to the VK tube.",
    "10. The method according to claim 8, wherein a plug flow of the melt is made possible in the first and the second flow tube parts by means of flow rectifiers.",
    "11. The method according to claim 9, wherein the prepolymer melt is transported through the outlet tube, by means of a discharge pump or by means of pressure in the reactor, to the VK tube.",
    "12. The reactor according to claim 2, wherein the static heating unit is a tube bundle, an internally heated overflow body, a plate heat exchanger or a heating coil, the dynamic heating unit is a Robert evaporator or a recirculation heater, and/or the static cooling unit is a tube bundle, an internally heated overflow body, a plate heat exchanger or a heating coil.",
    "13. The reactor according to claim 2, wherein an agitator is disposed above the heating unit.",
    "14. The reactor according to claim 2, wherein the VK tube is connected to a prepolymerisation reactor for the prepolymerisation of polyamides, the prepolymerisation reactor having an inflow region for the addition of educts, a heating unit, a first flow tube part which has a first wall heater, a second flow tube part which has a second wall heater, and an outlet pipe for the prepolymer, and the prepolymerisation reactor having, between the first flow tube part and the second flow tube part, a cooling unit.",
    "15. The reactor according to claim 14, wherein the cooling unit and the second wall heater are coupled thermally via a single heat-transfer medium circulation.",
    "16. The reactor according to claim 2, wherein the lower reactor region wall heater and the upper reactor region wall heater, independently of each other, are double jackets and/or half-pipe heating coils.",
    "17. The reactor according to claim 2, wherein the flow tube parts have, at least partially, flow rectifiers."
  ],
  "description_excerpt": "The invention relates to a reactor in the form of a VK pipe (VK: for the German “vereinfacht kontinuierlich”, i.e. simplified continuous), for the polymerisation of polyamides, the reactor being subdivided into an upper and lower reactor region, which are controllable independently of each other. Likewise, the invention relates to a method for the production of polyamides in which such a reactor is used.\n\nIn the production of highly viscous PA6 (with and without use of copolymers), two modes of operation are available to the producer at present. On the one hand, the production of high viscosity in the melt of the polymerisation reactors, on the other hand, by the use of solid-state postcondensation (SSP) in a subsequent treatment step.\n\nSince, as a result of the SSP, also undesired by-products (monomers) which disrupt further processing are formed, increasing the viscosity in the polymerisation step is always preferable.\n\nIncreasing the viscosity in the polymerisation step requires, because of the chemical equilibrium, the separation of water from the polymer melt. This is effected most effectively by additional reactor steps which are implemented in succession in pressure steps (with decreasing pressure). The water proportion is reduced thereby from step to step and hence makes possible the further viscosity increase. However, due to the additional number of reactors and associated equipment parts, increased complexity in the overall plant is thereby produced. As a result of the greater spatial requirement and more complex assembly, additional costs which are not acceptable for the producer result.",
  "cpc": [
    "C08G 69/16",
    "B01J 19/0013",
    "B01J 19/006",
    "B01J 19/1812",
    "B01J 19/2415",
    "B01J 19/245",
    "B01J 2219/00081",
    "B01J 2219/00083",
    "B01J 2219/00094",
    "B01J 2219/00164",
    "B01J 2219/00168",
    "B01J 2219/00774",
    "B01J 2219/182",
    "B01J 2219/1943",
    "B01J 2219/24",
    "C08G 69/14"
  ],
  "ipc": [
    "B01J 19/18",
    "B01J 19/24",
    "C08G 69/16",
    "B01J 19/00",
    "C08G 69/14"
  ],
  "assignees": [
    "Uhde Inventa Fischer GmbH"
  ],
  "inventors": [
    "Ekkehard Siebecke",
    "Johannes Katzer",
    "Bernd Königsmann"
  ],
  "filing_date": "2014-01-20",
  "publication_date": "2018-04-10",
  "grant_date": "2018-04-10",
  "priority_date": "2013-02-08",
  "application_number": "US-201414766045-A",
  "family_id": "47666033",
  "cited_by_count": 1,
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}