Q & A > Question Details
I am looking after Delayed Coker Unit.
One of the most obvious problem occurred in DCU is high skin temperature of heater coil due to different reason. Due to high skin temperature we are forced to run the unit with low throughput. Online spalling is not permitted by management due to some reason.
My query is to avoid high skin temperature in some section of the tube should we put off the burner near that section or can we pinched the burner?
But putting off the burner will increasing firing at the other section which may lead to coking up at that section.
So what should I do?
 
Answers
19/01/2018 A: Ashutosh Garg, Furnace Improvements Inc, agarg@heatflux.com
Your suggestion will work in short time. Try to have as uniform firing as possible in the heater with all the burners. It is not recommended as a long term solution. Burner flames need to be away from the tubes. It is possible to modify and improve the burner flame patterns by doing simple modifications.
12/07/2016 A: NS Murthy, Suez, murthy.ns.ext@suez.com
Can you indicate the magnitude of the problem i.e. rise in TMT in deg C or F per day? Why spalling was not favoured by management? Do you see the rise in TMT an uniform feature or sporadic? What is the velocity steam as percent of feed?
20/01/2016 A: Eric Vetters, ProCorr Consulting Services, ewvetters@yahoo.com
Adjusting the burner operation may help if the coke is forming in the lower radiant tubes. You could also consult a burner manufacturer. It is possible that a different burner design would perform better in your particular furnace.
If the high skin temperatures are occurring in the upper radiant tubes or convection section, adjusting burners will not help much. High skin temperatures in the upper part of the heater are usually due to contaminants in the feed and will form coke no matter what you do. If that is the case you need to work on desalter operation and trying to maximize solids and salt removal. There are a variety of strategies that can be employed in the desalter depending on the nature of what is causing the problem.