After commissioning of distillation unit we found that one of the passes of atmospheric furnace has encountered coke formation problem at the end of radiation zone. Is there any solution to continue the distillation process without doing shut down.
Answers
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20/03/2012
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Jayaraj Jayam, Chennai Petroleum Corporation Limited, njayaraj@gmail.com
If it is a new unit, please refer your records to find whether the furnace tubes, upstream of furnace inlet pipings (preheat exchanger) are flushed well. How did you identify the coke formation in the particular tube, by skin temperature or by flow indication?
Try to establish more flow in the tube which becomes the subject matter, compare to rest of the coils. Reduce the intensity of heat to the particular tube by reducing firing in the zone.
One more option but little risky one: In the case of accidental carryover of water from desalter along with the feed to atmospheric distillation tower, one can observe a lot of disturbances in pressure profile can be observed, some time to a magnitude of causing detrimental effect on the tower. At the same time, it is observed as preheat pick up improves in heat exchanger and also marginal reduction in skin temperature. Blessings in disguise! The accidental observation can be tested with utmost care in controlled manner. Water injection also has been practiced by many refiners at post desalter preheat exchangers to improve preheat. The same may be tried.
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19/03/2012
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Mike Watson, Tube Tech International Ltd, mike.watson@tubetech.com
We have a climbing robot that cleans and inspects vertical radiant and horizontal finned convection banks tubes to remove coke and refractory also. (In between tubes , 360 degrees surface contact)
We are also developing a live cleaning technology to clean convection asnd radiant tubes live on the run during full production
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19/03/2012
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A:
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Mike Watson, Tube Tech International Ltd, mike.watson@tubetech.com
We have developed a Robotic climbing robot to clean and inspect vertical radiant tubes and horizontal finned convection tubes. No more scaffoding, sandblasting or water jetting. Dry processs and is the only system to reach deep inside / between the tubes. TubeTech . com are currently researching a cleaning system that removes fouling whilst the fired heater / furnace is in full production.
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