Stainless steel heat exchange tube heat exchanger, baffle material selection
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Is there any problem with a stainless steel heat exchanger using heat exchange tubes made of 0Cr18Ni9, with an ethylene glycol aqueous solution as the fluid in the shell side, ordinary carbon steel for the baffle plates, and Q345R material for the tank body? Should the baffle be made of stainless steel?
The baffle is in contact only with the shell-side fluid, so it can be made of the same material as the shell-side casing.
What was said upstairs is correct; it’s sufficient to keep it consistent with the housing to prevent corrosion.
Why is 304 material used for the baffle plates? The 304 heat exchange tubes were chosen due to the properties of the fluid in the tube side, I guess
The baffle is made of stainless steel; will the baffle also get corroded when in contact with the cylinder? It’s true that the corrosion of baffle plates is better than that of pipes, but it’s still difficult to deal with. I just don’t know how severe the corrosion will be for stainless steel and carbon steel in an environment with water present
The material selection for heat exchangers generally involves choosing the materials for the shell side and tube side based on the nature of the fluid. Since the main shell of the unit as designed by the original poster is made of carbon steel, there is no need to use stainless steel for the baffle plates, which are not under pressure, are not subject to corrosion, and do not need to be welded to the heat exchange tubes or the shell. It would be quite a waste in such cases. We usually follow this principle when designing as well.
We tested two scenarios: stainless steel tube bundles with carbon steel shells, 1. stainless steel baffle plates, 2. carbon steel baffle plates. In both cases, shell corrosion was not significant. In the first case, there is no significant corrosion at the point where the baffle contacts the tube bundle; in the second case, there is significant corrosion at that contact point, with the baffle being more severely corroded than the tube bundle.
The baffle can be made of the same material as the main shell-side component.
Thank you very much. So how do you use it now?