Q & A > Question Details
We are facing problems with one of our reforming unit furnaces. There is a common duct in the three furnaces. The damper of the middle furnace is causing the problem. This damper falls several times after burning. The skin temperature of the tubes remain good but the stack temperature is higher than safe value by almost 150 degree Celsius (around 900 degree Celsius) . The furnace outlet temperature is operated below the design temperature by almost 25 degree Celsius. Our design temperature is 525 degree Celsius. The shaft, plate of damper used of stainless steel grade. We had changed burner tips several times but the problem was not solved. Please suggest me the cause and remedy of this problem.
01/05/2011 A: Ramadan Otman, AGOCO, rmsaleh@yahoo.com
As you are operating the common stack furnaces at low temp than normal, you should carry out a cross check all of your gauging equipment, also the Damper material to be compared with the other furnace dampers
18/04/2011 A: Sudhakara Babu Marpudi, Dangote Oil Refinery Company, m_sudhakarababu@yahoo.com
Check the health of the flames in the furnace. It is most probably an issue related to after-burn of the fuel. If the burners are on Fuel Oil, low viscosity of Fuel Oil, eroded Fuel Oil gun nozzles can lead to very tall flames, shifting the load from Radiation section to Convection section of the furnace. If the burners are on Fuel Gas, then adjust the air to burners. Gas flames will burn wherever combustion air is available, and the convection area is the definite area where unused combustion air will be available before the Flue Gas passes thru the convection bank (in view of back pressure). Idally the Flame length of a Fuel Oil flame (which is normally taller than the Gas flame) shall be around one third of the height furnace radiation zone (one third of the tube length for bottom fired vertical furnaces).
07/12/2010 A: SImone Robinson, Tube Tech International Ltd, simone@tubetech.com
The cause of your problem could be a cleanliness issue on the convection side.