What is the green aqueous solution discharged from the flue gas outlet of the air preheater?
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Cast-iron plate air preheater; flue gas temperature is controlled at 120. This phenomenon occurs only in cold weather, and the water discharged is green – is it an iron(II) solution? How should it be handled?
It is estimated to contain ferrous ions. Take a certain amount of water, add a small amount of base, stir it under air conditions, and let it sit for some time. Observe whether the color darkens to brown; if so, iron corrosion has occurred. Because it’s cold, the acidic components in the smoke are more likely to condense into acidic water, causing some dew point corrosion.
The steel plate is corroded; it’s fine as long as it’s drained
The ferrous sulfite liquid resulting from dew point corrosion can simply be discharged.
It turned red after two or three days; it’s probably ferrous