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Coke fines in the main tower

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This topic contains 5 replies, has 3 voices, and was last updated by  cjaviervarela 3 years, 10 months ago.

  • Author
    Posts
  • #25247

    Hedewandro Lucredi
    Participant

    We had a sudden leaking in the main tower bottom reboiler. This reboiler is by heavy gasoil circulation. Almost in the same time the bottom pump suffered a cavitation. We observed coke fines in the light gasoil and the sour water in top vessell . Is it possible that besides the coke fines carry over to the top sidestreams some coke fines affected the bottom pump ? The steam inside the tower from the leaking “washed” the internal tower and produced a lot of coke fines and part went to the bottom tower and affected the bottom pump? We observed coke fines in the pump suction filter or this coke fines found was from the bottom tower ?

  • #25251

    dblewis
    Participant

    Are there generally a lot of coke fine carryover from the drums? Do you have a foaming problem in the coke drums? Do you use a anti foaming additive?

  • #25261

    Hedewandro Lucredi
    Participant

    We checked and there is no fine carryover (huge space in drum top). No foaming problem. We use anti foaming 100000 cST. We think the problem was from any coke fines from packing beds, trays that the steam removed part of it.

  • #25300

    cjaviervarela
    Participant

    Coke fines will reduce the pump lifetime, but not probably cavitation. You can check fine at the bottom once per week to make history and try to predicted this kind of event.

    Yo could be ok with the foam control, but still suffer upset, check level indication (gamma or neutronics) and also top drum pressure (it usually suffer fluctuation during a foam over)

    Leaking of ligther material to the bottom could generate cavitation, how is yours experience with that pump during start up?

  • #25367

    Hedewandro Lucredi
    Participant

    During the start up we have some cavitation but after above a determined temperature the cavitation stopped.

  • #25451

    cjaviervarela
    Participant

    Lucredi, at the cavitation moment, you were operating at typical pressure and products?
    If not that could be the cause

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