Heat Recovery Steam Generator (HRSG) Learning Center
< back to esteemprojects.com
Thermal properties of water and steam Thermal properties of flue gas Combustion, supplementary firing Heat transfer coefficients Intube pressure drop Gas side pressure drop across tubes Ducting pressure losses Acid dew point of flue gas NOx and other considerations

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) =

Disclaimer:

The formulas and correlations presented herein are all in the public domain and are to be used only as a learning tool. Note that any product, process, or technology in this document may be the subject of other intellectual property rights reserved by sponsors or contributors to this site. This publication is provided as is, without any warranty of any kind, either expressed or implied, including, but not limited to, the implied warranties of fitness for a particular purpose, or non-infringement.

The formulas, correlations, and methods presented herein should not be considered as being recommended by or used by the sponsors of this site. The purpose of this site is educational and the methods may or may not be suitable for actual design of equipment. Only a fired heater design engineer is qualified to decide if a calculation or procedure is correct for an application.