What can cause acid leakage in anodic protection?
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Apart from 1. too low acid concentration, 2. damaged instruments, 3. poor quality of tube sheet welding, and 4. poor quality of heat exchange tubes, what other factors could cause acid leakage due to anode protection? Thank you!
During use, special attention should be paid to the main cathode; it is generally checked once during each major overhaul, and if it becomes worn out, it must be replaced. This is because the anodic protection acid cooler protects the anode by sacrificing the main cathode.
What you said is quite general; that’s about it. There is also potential drift, excessively high acid and temperature levels, the end of the device’s service life, damage caused by the cleaning of scale on the water side, and excessive levels of CL ions in the water quality!
If the acid contains impurities, such as fragments of ceramic rings, it can also cause corrosion. This type of corrosion is known as crevice corrosion, and it occurs in sulfuric acid at any concentration or temperature. It is easy to overlook this phenomenon, so special attention must be paid to it.
Another important factor is the quality of the circulating cooling water. Firstly, high water hardness can lead to scaling over time, which in turn causes corrosion beneath the scale; Secondly, excessive levels of chloride ions can result in stress corrosion. In addition, there are: 1. High outlet water temperature, which can lead to scaling and thus corrosion. 2. The exhaust gas absorption tower being located near the fiberglass cooling tower results in the absorption of acidic gases, making the water acidic. 3. Short circuits between the anode and cathode, leading to corrosion. 4. Frequent start-up and shutdown operations cause fatigue and damage to the heat exchange tubes. 5. Freezing of acidic liquids during winter shutdowns. 6. High current levels. 7. Mechanical methods used for cleaning scale can cause damage to the heat exchange tubes. 8. Damage to the acid coolers due to vibrations caused by various factors. I’ll add more if I think of anything else
In normal production, it’s important to pay attention to the acid concentration, temperature, and cooling water. As for the quality of the equipment, it’s pointless to discuss it once it’s already in use. Additionally, I think that any leaks of acid should be detected promptly and addressed early on to prevent the situation from worsening
This post was last edited by infowang2006 on 2016-5-10 at 18:23. Intergranular corrosion may occur at the welds; the acid temperature might be too high; the current settings controlled by the instruments may not meet the requirements; the equipment’s inlet and outlet might be installed in the wrong order; there are specific requirements regarding water quality (including chloride content and water acidity/alkalinity); and there are various methods for removing scale (some organizations use round steel rods for this purpose, which can easily cause damage to the pipe walls).