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Quench water control valve failure

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This topic contains 4 replies, has 3 voices, and was last updated by  Claus Graf 13 years, 3 months ago.

  • Author
  • #3020

    Freddy Martinez

    Hello.  Does anyone what would happen if the quench water control valve failed wide open at the beginning of the quench cycle?  Would the 1600 gpm of water totally vaporize and result in lifting the PSVs that go to the blowdown drum?

  • #6027

    Claus Graf

    If you have one 1600 GPM pump and the control valve is “fail open” then it could happen.
    Some cokers have 2 or 3 pumps to handle the total max quench water flow. (You start quenching with one pump and then turn on additional pump(s) as required.
    You can also have one 1600GPM pump with two control valves in paralell set up each to handle 800 GPM when completely open. These should be set as “fail closed”
    Hope this helps.
    Regards CG

  • #6026


    The use of 2 valves is not a good engineering practice

  • #6025


    What about if one valve was much smaller than the other valve.  The small valve is what would be opened first, and then once the coke is cool enough, the larger control valve would be opened.  Would that be good engineering practice?  What if the opening of the valves was a manual procedure?

  • #6022

    The typical design for these units are two valves in parallel, their design can be handled half the total flow of cooling, in the designs of FW, usually by placing a valve that handles between 20 to 30% of flow total and the other manages the total flow, this helps manage low flows (Rangeability) and when this is fully open the other begins to operate. Cooling ramps can be automatic based on the cooling curves of the drums, usually tries to maintain small flows  in the early hours and avoid problems of stress on the drums, there are additional protections to detect high pressure in the drum during this stage that stop the quenching  pumps

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