Tower Metallurgy for MEA Stripper
Tower Metallurgy for MEA Stripper
(OP)
I'm not sure if there is an industry standard practice for this but a customer is wanting to replace their MEA tower with some type of stainless. The current tower has 316SS cladding on a carbon steel shell. The cladding was damaged and the MEA + CO2 + H20 = Carbonic Acid has attacked the carbon and cracked the head of the tower.
Estimate of process conditions are
220 F
12 psi
What grade of stainless should the new tower be built out of and roughly what thickness? Is there a standard on this somewhere that I can get my hands on?
Thanks
Estimate of process conditions are
220 F
12 psi
What grade of stainless should the new tower be built out of and roughly what thickness? Is there a standard on this somewhere that I can get my hands on?
Thanks





RE: Tower Metallurgy for MEA Stripper
However, 300 Series Stainless Steels are extremely suitable for both Amine and Carbonic Acid service. The original damage your client got on their cladding may have been mechanical in nature possibly due to poor construction? Since the Amine and Carbonic acid is unlikely to have caused this. Thus 300 Series Stainless Steels should be suitable for your application. 304 SS or 316 SS.
The thickness would be based on your eventual calculations decided by your design pressure, design temperature and your choice of material type. You'll also need to determine the code of construction you'd like to use. ASME Section VIII Div 1 is widely used.
Also, and possibly most importantly, given the content of your post, I would strongly advise you consult with a mechanical engineer for this job.
RE: Tower Metallurgy for MEA Stripper
That being said, what the client wants, the client gets, but if you are interested in knowing more about the failure mechanisms present and their mitigations, have a read of API 571 and API 945.
RE: Tower Metallurgy for MEA Stripper
Picking the correct clad alloy and technology is critical.
Some locations in the unit require more protection than others.
You might look to see if there is any operational experience in building these in a duplex stainless.
This would greatly lower the amount of metal required (because they are high strength) and might allow the use of a more corrosion resistant alloy.
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Plymouth Tube
RE: Tower Metallurgy for MEA Stripper
The cladding was damaged during a repair of the outside shell. Unfortunately the client instead of repairing the cladding is considering cutting off roughly half of the vessel from the top down and welding a new section of tower made from 321 SS to the carbon section below it without cladding. (the cladding is only on the top portion of the vessel). However they are also considering building a new tower instead of the dissimilar tower/weld option. I will research the duplex option.
RE: Tower Metallurgy for MEA Stripper
You client did a repair on the outer shell, did they know they were supposed to PWHT the repair to prevent against Amine SCC?
RE: Tower Metallurgy for MEA Stripper
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Plymouth Tube
RE: Tower Metallurgy for MEA Stripper
RE: Tower Metallurgy for MEA Stripper
The failures occurred by welding the CS which damaged the SS. Thus allowing the MEA to come into contact with the non-PWHT(assumption) CS which eventually resulted in Amine Stress Corrosion Cracking.
RE: Tower Metallurgy for MEA Stripper
Either the inside was not cleaned well enough or the heat input was too high.
Sensitization, carburization, and sulfidation damage are all risks.
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Plymouth Tube
RE: Tower Metallurgy for MEA Stripper