4 replies to this topic

[Pheasant]

Hello everybody..

I'm now working in optimizing biomass power plant design.

I want to use maximum amount of heat available from the flue gas.

The sulphur content of the biomass is 0.05%, and the system will be using dry sorbent injection for flue gas desulphurization.
From the formula I found on this forum, the acid dew point will be approximately be 70C.

The question is, what will the minimum allowable stack temperature be?
because I read in some rules-of-thumb article, that power plant with natural gas as its fuel will generally produce flue gas with acid dew point of 55C, but its minimum stack temperature should be >100C

Now I'm wondering, what exactly is the correlation between dew point and minimum stack gas temp?

Thank you,

[S.Chittibabu]

May be this link helps
http://www.jehar.com/dewpnt.htm
The stack temperature should be more than 30~50 deg C than the dew point.

[Dacs]

Dew point, especially for flue gases with acid gases, is an indication on how low (temperature) you can operate without the possibility of corrosion (due to condensed acid gas) by placing some margin above the dew point temperature.

[T.S.MURALI]

Based on the pressure fraction, you know the volume fraction.

Based on the concentration of condensing gases ,you can get the Dewpoint.

Lower the concentration , the dew point will be lower -which means you can extract more( heat )energy by keeping the exit gas temp at +20 Deg above condensing-dew point temp.of gases.

Numerical calc., charts , Mole frn/Partial pr vs Dew point are available.

[T.S.MURALI]

YOU MAY REFER DEWPOINT CALCULATORS-Perma pure llc site for further info.