The acidity and alkalinity issues of saline corrosion inhibitors
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Gentle experts, I’ve run into a practical problem; please help me out and discuss it together. Our indirect refrigeration system uses a brine solution, and corrosion inhibitors need to be added; however, these inhibitors come in acidic and alkaline types. Under normal conditions, at a specific temperature and with an alkaline pH of 7.5–9.0, the corrosion rate of carbon steel pipelines is at its lowest; therefore, it makes sense to use an alkaline environment. But under what conditions is this acidic corrosion inhibitor used? Moreover, its pH is around 2-3, which is in the range of strong acids; isn’t there a risk of corrosion to the pipelines if large amounts are used? :o
It depends on what kind of salt it is. After hydrolysis, if the acidity increases, add alkali. . If the pH is too alkaline, add acid – that’s how I understand it; I look forward to other insights.
Normally, saltwater isn’t just calcium chloride and sodium chloride? And isn’t it true that saltwater is slightly alkaline? I haven’t figured it out either
For this case, only alkaline corrosion inhibitors can be used; by alkaline, we mean slightly alkaline or neutral-to-alkaline conditions. Acidic corrosion inhibitors are needed when the medium is acidic. Since this is saltwater, it’s sufficient to use a slightly alkaline corrosion inhibitor – acidic corrosion inhibitors are generally not suitable in this situation