Dewpoint of moist Hydrogen Fluoride in flue gases

[WaltNiessen]

I have concerns regarding condensation and subsequent corrosion in the metal parts of a boiler that follows an incinerator burning a fluorocarbon (generating HF in the flue gases). HF concentrations can be as high as 5000 ppm. I cannot find a correlation with which to estimate the dewpoint as a function of HF and H2O partial pressure.

 

[kenvlach]

The boiling point of pure HF(liq) is 20 ^oC.
The boiling point of 49 wt% HF(aq) is 106 ^oC.
So, the condensation seems dominated by water. After finding the condensation temperature for the water vapor pressure, look up the solubility for HF in aqueous equilibrium with the 5000 ppm (wt or volume?) of HF in the gas phase. I.e., check the vapor-liquid equilibria for hydrofluoric acid. Probably very minor effect on condensation temperature of such a dilute [HF].

Excellent source of HF & Hydrofluoric acid information:

http://www.honeywell.com/sites/sm/chemicals/hfacid/technical_documents.htm