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Minimum residence time

Home Forums Coking Technical Heaters & Furnaces Minimum residence time

This topic contains 1 reply, has 2 voices, and was last updated by  Evan Hyde 6 years, 5 months ago.

  • Author
  • #22226

    Hedewandro Lucredi

    What is the minimum residence time to consider that there is coke formed inside the drum (considering that all operation conditions are normal)?
    If a heater trip occurs and the drum remains purging for a long period of time, what parameter should be analyzed to confirm if the combined feed can be aligned to the same drum, after heater normalization? Only drum temperature? Is there a reference value?

  • #22472

    Evan Hyde

    The conventional time to trigger a short run drum procedure varies around the industry but it is 4-6h as a general rule to ensure a reasonable bed of coke has been formed.

    2nd question is very, very, very complicated. Things like position in cycle (start, middle, end), drum-in and out temperatures before the incident. Foaming and quenching problems are likely if not done properly…. proceed with caution. When in doubt, bypass and feed a new drum after lining out the heater.

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