How to address high iron ion levels in acidic water from atmospheric and vacuum distillation?
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Increasing the corrosion inhibitor dosage has no significant effect
It should first be determined whether it is caused by high-temperature corrosion or low-temperature corrosion. There are corrosion inhibitors specifically designed for the stripping of acidic water, namely inhibitors tailored for acidic water that can complex carbon dioxide.
I wonder what the iron ion content in the acidic water from the atmospheric and vacuum distillation units of your plants is? What is the control range for the indicator? Generally, the iron ion concentration in the acidic water at the top of the tower should be kept between 1-3 ppm; if this concentration is too high, it indicates that corrosion is occurring at that location.
This post was last edited by Yongan Environmental Protection on 2017-5-31 at 10:49. The corrosion that occurs at the top of the tower is generally referred to as dew point corrosion; it happens when the acidic gases present in the gas and oil at the top of the tower condense into ammonium chloride and ammonium hydrogen sulfide when the temperature drops to a certain level. When water injection or other treatment methods are not effective, strong acids are formed, leading to localized corrosion. You can refer to: http://bbs.hcbbs.com/forum.php?m ... 6424&extra=page%3D1
When adding corrosion inhibitors, there is a required film-forming period, so the effects are not immediate. As for the control of the pH value in acidic water, was the level of iron ions high all along or did it increase suddenly?
To determine the cause, it is first necessary to know whether it is an excess of acidic water at normal pressure or a reduction in pressure, as the corrosion conditions in these two situations differ. Many factors can affect the corrosion problem caused by atmospheric and vacuum distillation acidic water, including whether the corrosion inhibitors are of suitable quality, pH control, dew point locations, and the operating conditions of the secondary air cooling system; a comprehensive consideration of all these factors is necessary to determine the most appropriate solution.