Low-Excess-Air Combustion of Heavy Fuel—High-Temperature Deposits and Corrosion

Considerable interest has been shown lately in the operation of oil-fired boilers at minimum excess-air levels to minimize superheater deposits and air-preheater corrosion. This paper presents the results of rig-scale studies which were aimed at determining the extent of the benefits to be derived from the low-excess-air technique. These studies showed the effect of low excess air on SO₃ and nitrogen-oxide contents of the flue gas, on the rate of slag deposition on superheater tubes, and on the rate of corrosion of superheater tubes. The level of excess air necessary to obtain these benefits was also determined.