Deplugging of bend pipes in bitumen column

[8069]

We have a Biturox plant in refinery producing bitumen of different grades.
At the top of column , we have a bend pipe (8" dia) of length 1080 mm and 660 mm vertical for collecting offgases. It gets choked frequently. Hard coke gets deposited in the pipe section. After removing pipe flange, we can only able to deplug the horizontal portion of 1080mm length. We are not able to deplug the vertical portion with pipe inside the reactor.
Any body , has idea of how to deplug the bend pipes ?
please let me know.
thanx

 

[Rich2001]

I have had cases where I used a small explosive charge to unplug or remove buildup on the sides. This, however, is generally after all other options are exulted.

A few options:

Try a high pressure spray of a hot middle distillate to try to cut.

Contact a pipe freezing company, by lowering the temperature of the coke to LN2 or LCO2 may cause the coke to crack , i.e. facilitating removal.

Apply several powerful ultrasonic trandusers to the outside of the pipe , the eneregy from the transducer may remove the coke build up. Contact Crest Ultrasonic, at http:/

http://www.crest-ultrasonic.com/home.html

see if they can help.


My concern is how to prevent this from happening again?
I would check the size of the holes in the oxygen spargers, you want the reaction with the vacuum resid to occur in the reactor portion not at the offgass pipe outlet.

Is the offgass pipe too small? or bend too tight? both cases generaly lead to plugged piping.

Is the volume of oxygen injected into the reactor too great causing a carry over?