Corrosion problems in stainless steel heat exchangers
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It is a stainless steel heat exchange tube heater, with the fluid in the shell side being an ethylene glycol aqueous solution. The heat exchange tubes are made of 0Cr18Ni9, while the baffle materials are ordinary carbon steel. The tank body is made of Q345R. Will the contact between the baffles and the heat exchange tubes cause corrosion of those tubes? Electrochemical corrosion? (I posted a request for help before; I think I didn’t explain my doubts clearly enough, so I’m asking again. Thank you.)
What medium is in the shell side? It can generally be designed in this way; as long as the fluid in the shell side does not have a tendency to corrode stainless steel, there is no need to consider electrochemical corrosion. Personal opinion.
http://bbs.hcbbs.com/thread-1405373-1-1.html The original poster has already made things pretty clear in this post; there is no need to use stainless steel for all the shell-side accessories such as baffle plates.
Thank you. I’m just worried about the issue of electrochemical corrosion that can occur when stainless steel comes into contact with carbon steel; I’m afraid that the baffle plates might corrode the heat exchange tubes and cause leaks
This is different from the battery circuits used in electrochemistry.
Electrochemical corrosion occurs due to a potential difference; one can determine whether there is such a difference between carbon steel and stainless steel by checking this. When stainless steel comes into contact with carbon steel, under normal conditions, the potential of stainless steel is more positive than that of carbon steel; as a result, carbon steel acts as the anode and gets corroded. Of course, if the area of carbon steel is larger than that of stainless steel, it is a large anode, and there’s no problem. If the area of stainless steel is large, carbon steel will also corrode.
There’s no problem with that; we all do it this way
The waste heat boiler for sulfur recovery in my home uses 50% ethylene glycol as the heat transfer medium; its tube bundle is made of 20G material, and the baffle plates are made of carbon steel. It has been in use for many years without any signs of corrosion. However, if ethylene glycol comes into contact with an acidic environment (such as in the event of a leak), corrosion can occur quite severely.
The tube bundle is 20G, no problem there; our customers want stainless steel heat exchange tubes, while the baffle plates are made of carbon steel