• The Combustion Process
  • Burner Types And Selection
  • NOX And Other Considerations
  • Purpose Of Excess Air
  • Preheated Combustion Air
  • Acid Dew Point Of Flue Gas
  • Flame Temperature
  • Acid Dew Point Of Flue Gas

    To improve the thermal efficiency of combustion equipment it is necessary to cool the flue gas to a low outlet temperature, to recover as much heat as possible. But the temperature must not be so low as to allow sulphur from the fuel to condense as sulphuric acid, resulting in a very corrosive flue gas.

    The two graphs below indicate the maximum flue gas dew point versus sulphur content in typical fuels.

    Maximum flue gas dew point versus percent sulphur in typical oil fuels:
    % Sulphur In Oil Fuel

    Maximum flue gas dew point versus percent H2S in typical gas fuels:
    % H2S In Gas Fuel
    Acid Dew Point Of Flue Gas Calculator :
    This calculator uses the method described by A. G. Okkes in Hydrocarbon Processing, dated July 1987, pp 53-55. The SO3 conversion from SO2, if calculated, is assumed to be set by equilibrium at 1000 °C. The flue gas is assumed to be at atmospheric pressure. A deviation of 200mm H2O will result in a 0.4 °C error in the predicted dew point. Flue Gas Composition, mole %
    Nitrogen =
    Oxygen =
    Carbon Dioxide =
    Water =
    Argon =
    Sulphur Dioxide =
    Sulphur Trioxide(Input C to calculate) =