Incinerator operation
Incinerator operation
(OP)
Hi,
Flue gas from incinerator goes through to a stack whereby the gas is 'sucked' through a venturi srucbber and scrubbed with low purity water to remove any dust particles in the gas. Recently we experienced the section just above the gas inlet nozzle to the stack thinning off and it was suspected that there's corrosion due to dissolved CO2 (produced from incineration). I wonder how soluble CO2 would be in water for that short period of time. This is further supported because pH of water in the stack was tested to be 8. Wonder if anyone has this similar experience?
Thanks.
Flue gas from incinerator goes through to a stack whereby the gas is 'sucked' through a venturi srucbber and scrubbed with low purity water to remove any dust particles in the gas. Recently we experienced the section just above the gas inlet nozzle to the stack thinning off and it was suspected that there's corrosion due to dissolved CO2 (produced from incineration). I wonder how soluble CO2 would be in water for that short period of time. This is further supported because pH of water in the stack was tested to be 8. Wonder if anyone has this similar experience?
Thanks.





RE: Incinerator operation
Is it possible that it is mechanical corrosion due to high velocities?
hth,
chris
RE: Incinerator operation
2. SOx content could also be considered a factor especially if the flue gas is at a temperature below the dew point of sulfuric acid. A combination of HCl+water+CO+SOx has been identified as a corrodent in incinerators by helping in removing the iron oxide protective layer by causing its disruption and spalling, exposing new surface to corrosion, thus bringing about metal thinning.
3. A note on the pH subject at ambient temperatures. At pH~8, the approximate pH of seawater, of the three species H2CO3, CO=3 and the ion HCO3-, the latter is the most prevalent. Their approximate mass fractions in water being 4%, 1%, and 95%, respectively.
RE: Incinerator operation
The incinerator handles EG waste and so I can expect the flue gas to consist of CO2, H2O, N2 and O2 and small amount of NO, NOx (~20ppm), CO (~100ppm). Low purity water is just like demin water.
I am also thinking along the line that it could have been due to the flow profile of flue gas and low purity water used. Like to understand how gas escaping from water works and its impact of erosion/ corrosion.
Thickness check along the stack seems to suggest the thinning effect is not uniform and it's an indication of possible pitting corrosion.
raingal79
RE: Incinerator operation
Temperature of the flue gas entering the scrubber? This sounds as a scrubber plus quenching.
Oxygen + water + high temperature... means corrosion for a CS, depending on concentrations.
I think that you may have good answers in the Corrosion Engineering forum. Suggest to repeat the question there.
Have a safe day
J.Alvarez
RE: Incinerator operation
However it is possible that the pH is not representative, either beacuse you have peaks of pollutants that escape the venturi (a Venturi is not that good a scrubber), or because fine ash entrained manage to neutralize the waters.
Have you tested for chlorides and sulfates in this water?
At any rate, I do not think that CO2 is your problem.
RE: Incinerator operation
See jalvarez reply above.
Sounds like you are quenching a hot gas stream with a copious amount of water. Calculate your O2 balance