Home › Forums › Coking › Operations › Cutting, Drilling, Unheading › Cutting › DECOKING PROCEDURE
This topic contains 7 replies, has 5 voices, and was last updated by Lucibar Davalillo 9 years, 9 months ago.
June 5, 2009 at 11:25 am #3086
Hi there!!! Im new in the operating part of the coker and I need help… We are having problems with our decoking hardware. We are experiencing failures frequently in the rotary joint system (once a month). One time is the rotary, other the air-driven motor, another time the reducer… I was looking how the drilling/cutting was done and I saw something that left me astonished… When drilling the operator punctures the coke surface. I talked to him and told me that is a common practise done for years and they call it “punctured of the drum”. I think that this is the cause of the problems… Can you recommend me the best method or procedure to drill/cut the drum without making the equipment suffer??. By the way is there a recomended maintenance guide to keep all the parts operating in good conditions?. We have the system of two tools, one for drilling and one for cutting.
Id be very appreciated if you gimme a hand.
Thank you very much!!!
June 6, 2009 at 2:21 pm #6113
There is no such thing as “puncturing” recommended in any of the decoking procedures i have read; it seems to be just a poor practice from old dogs, which must likely may be due to lack of follow-up and/or maintenance of cutting equipments; it cuoud be due to low cutting pressure, damaged nozzles, between others. Procedures vary for different cokers depending on the available system, either hydraulic or air driven, but frequent preventive maintenance is a constant for all.
June 7, 2009 at 6:52 pm #6111
antonio saura CebrianParticipant
THERE ARE SOME POINTS TO ENSURE a good cut, we had many problems with the Rotary joint, we did some change in ours procedure taking the best practice for several procedure, here some Highligth in order to avoid dammage to the rotary
-Speed of rotation of rotary between 8 to 12 RPM,
-Cutting speed dropping between 3 to 4 ft / min (there are people that cut higher speed, which can generate the tool beaten the bed coke (these can lead to breaking some bearing inside the rotary) (actually this systems have a protection in order to avoid that)
-Cut the coke bands stripe between 3 to 5 feet,
-Cut from the tope to the bottom
Carlos if you read spanish I can send you some procedure, let me know, Best Regards
June 7, 2009 at 7:43 pm #6110
We have had similar problems to yours and we have done a close follow up to the cuttings operations. In that way, we have improved our cutting procedure and, similar to the other partner, if you read spanish, I can share it ours with you… I hope it can be useful for your operations….
June 8, 2009 at 7:57 pm #6109
How many cokers cut top-bottom? I have experienced an increase in coke fines when doing so; my preference is bottom-up, even though the risk for trapped tool due to cave-ins.
June 8, 2009 at 10:43 pm #6107
antonio saura CebrianParticipant
Well I can tell you for my experience Ive been work in 14 coker and all cutting from top to the bottom, the coke fines can be generated by many factors, the cutting pressure , the penetration velocity of the tool inside of the drum etc
January 16, 2011 at 9:41 pm #5334
I use the bottom to top. Normally the bottom is harder and “chunky” and the water drains really well and then I cut the top “soft stuff” which usually all falls out completely. I then shut down the jet pump so I put as little water on top of the soft coke which keeps the fines to a minimum
June 13, 2013 at 5:26 am #4454
Great information about coking and decoking. I was new in this topic but after reading all the comments I came to know lots of new things about coking.
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