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Top Unheading Ergonomics & Hazard Mitigations

Home Forums Coking Operations Cutting, Drilling, Unheading Unheading Top Unheading Ergonomics & Hazard Mitigations

This topic contains 6 replies, has 4 voices, and was last updated by  Ken Osment 17 years, 1 month ago.

  • Author
  • #4356

    James Arney


    Our coker drums are unheaded manually on top and bottom. We are looking at the top unheading/heading operation and want to mitigate the ergonomic issues associated with head removal and installation.

    Ergonomic Issue -> Our top drum flanges are are about 12″ above the deck and the operators are constantly bending over with a impact gun to remove or install the bolts for the top head removal or installation.

    Hazard -> In addition we want to address a potential hazard when the top head is removed and we have a open drum top 12″ above the deck until the stem is lowered into the drum. The same is true after the cut of coke is complete and the stem is removed from the drum prior to the head being placed on top of the drum.

    Obviously the Delta or Enpro Valves will provide the answer for these issues at a large cost.

    What other means have refiners taken to mitigate the ergonomic and hazard issues on the top head deck?

    Any and all responses will be greatly appreciated.

  • #7819

    Ken Osment

    I know of a number of operations which use captive nuts and self piloting bolts to secure the top heads. Essentally just the impact gun is required and the nuts can be chaned quickly if one becomes damaged. To gain added height the impact guns gan be bought with extended shafts which will elevate the gun slightly. If you have the time (approx 2 additional minutes per drum) there are a number of pneumatic torque tools which go one step further and elliminate the nerve damage associated with repetitive impact tool use.

  • #7809

    James Arney

    Kosment thanks for the info!!!!!

    I am also looking at the addition of a spool on top of the drum to raised the head location to more the waist level. This will help with the ergonomics and the safety issue when a drum top is open prior to the drill stem being lowered into the drum or when the stem is removed from the drum prior to the top head being installed.

    I like the idea of slowing down a bit and using a torque wench instead of a impact gun.

    Does anyone else have any suggestions?


  • #7787


    On my unit we have a figure eight type spool on the top head of the coke drums. While the head is about 18 inches from the deck it doesn’t really create a problem for the operators to head up and unhead. The head and stem guide are connected together and swing around on a pivot when heading up/unheading is taking place. The opening is 36 inches wide and while this could create a hazard to an unwary/inattentive operator the chances of anyone actually falling in are somewhat remote. I would not be in favor of using any sort of automatic valve on the top heads as there has been a tendency in the past to over-engineer the top and bottom heads in the interests of safety. The setup we have is just about ideal from a reliability and practical point of view. Having said that, we are supposed to get 4 new Delta valves on our bottom heads during the next turnaround in 2007. Our sister unit already has them and they apparently work very well.
    Hope this helps.

  • #7782

    Mark Czech

    James – we have a spool at the top of each of our 6 drums which puts the top head cover at about waist high. It works very well. The only issue we had recently was that the spiral wound gasket in one of the drums started to unwind. We pulled it and installed a CGI (center guard insert) type of spiral wound. In addition, we also have the captivated nuts with the self centering bolts and they also work very well.

  • #7728


    Hahn and Clay offers a wide range of options that can be installed.

  • #7682


    I worked for a large refinery here in Houston. On the top deck I installed a reel that supported the gun used to remove the top head bolts. If you want to talk about it, you can call me at 281-728-2292.
    david jordan

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