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Metal shavings from pigging Coke Heater

Home Forums Coking Maintenance Pigging Metal shavings from pigging Coke Heater

This topic contains 6 replies, has 1 voice, and was last updated by  Anonymous 10 years, 10 months ago.

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  • #3775


    We just completed pigging our Coking Heater and noticed that there was a significant amount of metal shavings in the drums where the pigging company emptied the coke removed from the heater.  We have not noticed this in the past.  Our heater tubes are 347 Stainless.  Has anyone seen this issue and do you have any recommendations?  Our concern is if this continues to happen it could result in significant metal loss over the course of repeated piggings.  Also, it may increase the coking rate in the heater from having grooves for coke build-up.  Any thoughts or suggestions are appreciated.

  • #7022


    Does this heater have u bends or Mule ear plug headers?

  • #7018


    Having been involved in the pigging industry for the last 12+ years, I have seen this on occasion, probably due to one of the following:

    –   an overly agressive pigging operator
    –  OR which would be the case if using our technology, these shavings may be filings from the ‘sacrificial’ appendages used when pigging close to the tube wall. We (and I think all the others in the industry) when pigging at full ID, use appendages that are softer than the tube material in order to mitigate the chance of tube scoring.
    – OR which I personnaly have observed, is that the heater design incorporates u-bends with heavier wall thickness than the tubes, so there is some extra material to compensate for high velocity errosion when using SAD or on-line spalling. (eg: schedule 40 tubes with schedule 80 u-bends) With this smaller ID in the u-bends, it is extremely difficult to remove coke to the tube ID without some scoring of the u-bends.

    It would obvioulsy be in everybodies best interest to discuss this with your pigging company rep.

    For the record, our company does not work in North America yet, so I doubt I am defending our group.

    Please feel free to call if I can be of any assistance.

    Linc Drynan
    Critical Path Decoking Technology
    001.403.396.2381 (Canada)


  • #6776


    Yes.  We have seen it.  You should question (and come down hard on) your pigging company on their choice of pigs and consider switching companies.  Using Eveready?  Have them make a presentation in front of your management as to how they intend to reduce the quantity of metal shavings.  Increase your monitoring of their activities. 
    Online spalling and steam-air decoking are options, of course.  My experience is with steam-air decoking and pigging.  Steam-air decoking can be optimized such that it can be performed almost as short as it takes to pig a heater.  As I recall, we were able to able to achieve as low as 60 hours oil-out to oil-in with steam-air decoking whereas pigging can be accomplished comfortably in a 48 hour time frame.

  • #6608


    Analyze the shavings and see if they are carbon steel.  If there is a lot of piping fabbed up to mount the launchers at ground level they will be scored very easily, between the appendages and piping the shavings will look like a lot more than they actually are.
    Talk with the pigging company and let them know your concerns.  If it is DDT let them know you dont want any tungsten appendages used after a set diameter (the ddt appendages stick out past the pig body so they will cause scoring before full ID is reached).  If it is eveready it is purely operator error as the appendages they use are much safer (but dont work nearly as well).
    DDT has the most versatile system but if used improperly is the easiest to damage pipe with.  Make sure you know the actual ID of the tubes, if there have been replacements check what went in and let the pigging company know. 
    DDT has the most experienced crews in North America,  Eveready has lost most of the Pinnacle guys. 
    I worked in the industry for 12 years for all the major players in north and south america but no longer have any connection (other than drinking beer and telling lies about the old days)

  • #6286


    Amen brother.  The studs on the pigs are too hard and must be lower than the tube metals.
    Sim Romero

  • #4679


    Running an efficient hydroblast process such as Aqua Milling from Aqua Drill International will prevent any wall damage at all. The process will need every 4th mule ear cut but the process is more effective and faster than pigging as well as extends the life of the tubes.

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