- Galvanic Corrosion - Wiki Reference
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The cooler is an interstage cooler in ASU unit for oxygen compressor. The cooling water flow is on shell side while gas was on tube side. Tubes were of SS & shell including baffles were of CS carbon steel. It seems that heavy corrosion has eaten away all the baffles.
If you can enlarge the photo & see it carefully then you will find marks of existence of those baffles.
Another example of similar type of corrosion is seen in other exchanger. This is a condenser for heavy glycol ether vapors. Cooling water is on tube side. So the corrosion is observed on tube sheet & partition plate.
The opposite side was also no better. In fact the damage is more here.
This is mainly due to electorlytic corrosion induced by presence of salts in cooling water. The easiest way to reduce it is to provide a Zinc Anode so that preferential corrosion or sacrificial corrosion saves your exchanger without much effort. One example is shown below.
These examples indicate that the cooling tower which is supplying cooling water to these exchangers doesn't have proper makeup water & has build up the concentration of salt beyond desired levels.
One should keep in mind that the contact of Zinc on the surface to be protected should be proper. In fact, one should prepare it by buffing or some other means to make it very clean.
Also keep in mind that there should not be any paint or coating on Zinc Anode as it is seen on some points in above image. This defeats the purpose of providing zinc anode. It is an usual thing that when you are in a hurry during shutdown you leave the job on contractor. The labourer does his best by providing coating on Zinc Anode also...............HOW Zzzzz THAT????????
So be careful, sometimes good thing are not so good to do.
Yes as an initial step we provided Zinc anode in these two exchangers.