2205 Duplex vs Carbon steel
2205 Duplex vs Carbon steel
(OP)
Hi Everyone,
We are choosing a tube bundle for one our alkylation unit Heat exchangers. We have Water(City water and smetimes Fire pound water) with some caustic carry-over in the shell side and the product in the shell side.I have been given two options by inspection department.
1- SA- 179 SEAMLEASS Carbon steel
2- 2205 Duplex welded
Water goes to the tune side and heat up to 120 F.
I would be happy to have any suggestion on this subject.
thanks
We are choosing a tube bundle for one our alkylation unit Heat exchangers. We have Water(City water and smetimes Fire pound water) with some caustic carry-over in the shell side and the product in the shell side.I have been given two options by inspection department.
1- SA- 179 SEAMLEASS Carbon steel
2- 2205 Duplex welded
Water goes to the tune side and heat up to 120 F.
I would be happy to have any suggestion on this subject.
thanks





RE: 2205 Duplex vs Carbon steel
How has it failed?
If you have decent water treatment then the CS should be fine on the water side. What about the product side?
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Still trying to help you stop corrosion.
formerly Trent Tube, now Plymouth Tube
eblessman@plymouth.com
or edstainless@earthlink.net
RE: 2205 Duplex vs Carbon steel
- If it is for tube bundle replacement (not for new construction), what is the root cause (premature failure or retired-prolonged design life)? How long has it been operated? Were there any corrosion phenomena in tube side? Was there galvanic or crevice corrosion? Was the failure local/cracking or general corrosion? Was there erosion or wearing near the inlet or baffles?
- H/EX TEMA type? Horizontal or vertical?
- Chemical composition of the water : (chloride, TDS, Alkalinity, Calcium Hardness, pH, SRB, caustic, etc.)
- Operating temperature (normal, maximum, 120F & time, upset & time) on shell & tube sides respectively
- Water velocity in shell side
- What are the present materials of tube and tubesheet?
- Why do you consider only two materials (CS & DSS)? How about 304(L) SS, 316(L) SS, etc?
- Any chemical treatment in water side?
- Any other operating/maintenance history for this failure
RE: 2205 Duplex vs Carbon steel
We do not have any treatment on the water side. on the product side, I should not see anything, however, i might have acid soluble oil in my product stream.
RE: 2205 Duplex vs Carbon steel
i'll consider to use a SS 316L if the chlorides are not to high in the process fluid and water side.
S.
http://www.corrosionist.com
RE: 2205 Duplex vs Carbon steel
= = = = = = = = = = = = = = = = = = = =
Still trying to help you stop corrosion.
formerly Trent Tube, now Plymouth Tube
eblessman@plymouth.com
or edstainless@earthlink.net
RE: 2205 Duplex vs Carbon steel
RE: 2205 Duplex vs Carbon steel
More specifically, I recommend a thicker gauge CS tube for a longer service life, OR if Ops wish to consider the lifecycle cost, then retube in 2205.
Why 2205 rather than 304/316etc? 2205's thermal expansion is similar enough to CS that it can be a direct swap over. We have even mixed the two materials throughout a bundle and haven't found galvanic issues.
Another reason why I might strongly suggest 2205 over 3xx stainless in certain instances is that 2205 is more resistant to erosion corrosion.
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