What is the excess air coefficient in a heating furnace?
Thread Content
What is the excess factor in a heating furnace? What are the risks if it is too low? And what are the consequences if it is too high? This post was last edited by whq520 on 2008-1-24 13:24.]
Excess air coefficient? This concept exists only in heating furnaces. Please, the landlord, listen carefully.
Hehe, yes, it’s that excess air coefficient inside the heating furnace. Could you explain it?
When fuel burns in air, it consumes a certain amount of oxygen. With the fuel amount fixed, the theoretical amount of oxygen required is also fixed; therefore, the amount of air needed is as well fixed. However, in actual combustion processes, it is not possible to provide only the amount of air calculated theoretically, as this would result in incomplete combustion of the fuel, leading to waste of fuel and environmental pollution. But if too much air enters, since the exhaust temperature of any furnace is certainly higher than that of the air, an excessive amount of air will require additional energy to heat up the excess nitrogen, thus consuming extra energy and reducing fuel efficiency, which is also uneconomical. Therefore, the excess air amount is the result of a balance between two factors. (Actual air supply – Theoretical requirement) / Theoretical requirement
thank you very much
An excessively high excess air coefficient can cause the flue gas temperature of the furnace to rise, thereby reducing the thermal efficiency of the heating furnace
The person upstairs gave a very accurate answer to the definition. Being too small can lead to incomplete fuel combustion. Being too large will cause the air to carry away more heat, accelerating the oxidation of the furnace tubes.
Excess air coefficient = Actual air flow rate / Air flow rate required for the theoretical complete combustion of fuel. An excessively low excess air coefficient leads to incomplete fuel combustion, resulting in fuel waste and air pollution. An excessively high theoretical air coefficient results in sufficient combustion, but it introduces excess air that carries away a large amount of heat, causing heat loss and thereby reducing the heating efficiency.
An excessively low excess air coefficient leads to incomplete fuel combustion, which causes afterburning, resulting in overheating of the rear coils and increased vibration of the furnace