What are box, skin and arc temperature? What is the sequence in magnitude of all these i.e. which one is higher than another in a furnace?
Answers
|
01/05/2019
|
A:
|
Sudhakara Babu Marpudi, Dangote Oil Refinery Company, m_sudhakarababu@yahoo.com
Box temperature is the Flue Gas temperature in the fire box (indicates the heat available for radiant heat transfer from the Fuel fired), Skin temperature is the tube metal wall temperature of the tube carrying the liquid to be heated (temperature beyond specified skin temperature limit, indicate the fouling of the tube / increased wall thickness - lesser heat transfer from the flue gas to the process fluid to be heated). Lastly Arc / Arch temperature indicates the temperature of Flue gases leaving the radiation section (after maximum possible heat transfer) and entering Convection bank. Higher Arch temperatures indicate lower heat transfer in radiation zone (for whatever reasons -fouled tubes, longer flames due to improper air supply to the burners, gas risers with blown tips etc., causing after burn of fuels). Normally the furnace temperature profile will be box temperature, skin temperature and arch temperature in descending order as the heat is absorbed from Flue gas (will loose the temperature as it flows towards the stack).
|