Amine (aMDEA) Reboiler material selection 3

[Co2corrosion]

Hi Guys, I am dealing with a project to upgrade existing amine reboiler. I have been told that CS shell & bonnet along with SS316L U-tubes rolled in CS tubesheet can be used in this service. Anyone could confirm if such metallurgy has been used in amine reboilers and works fine with high levels of CO2

 

[SJones]

http://www.eng-tips.com/gsearch.cfm...=ISO-8859-1&q=amine++materials&sa=Search#1122

Steve Jones
Materials & Corrosion Engineer

http://www.linkedin.com/pub/8/83b/b04

 

[Co2corrosion]

Thank Steve. I am actually looking for a specific answer on CS tubesheet and SS316L tubes in amine reboiler. What would be the dominant corrosion mechanism. Galvanic corrosion or CO2 corrosion. Would CS & SS form a galvanic couple in the pressence of less conductive amine and high pH. Is there a likely mechanism of crevice corrosion at tube/tubesheet interface?

 

[SJones]

The intent was to give you leads to research yourself. There were many references to follow up in the listed threads, particularly EFC 46. Amine reboilers can be pretty fierce environments. High temperature, erosive turbulence, etc. Carbon steel in aMDEA with CO2 should be passivated by a FeCO3 film. Whether that would occur when coupled to stainless steel I couldn't say. MDEA is the least aggressive of the alkanolamines when correctly operated and maintained. Getting chlorides into the system will soon see off your stainless tubes so neither material is totally safe. There probably wouldn't be a driver for crevice corrosion if you keep an oxidising species, principally oxygen, out of the system. Amine corrosion under turbulent conditions and heat stable salt contamination is likely to be the main mechanism. Personally, I would go for an all stainless (cladding allowed) reboiler and keep the chlorides out.

Steve Jones
Materials & Corrosion Engineer

http://www.linkedin.com/pub/8/83b/b04

 

[rustbuster]

I totally aggree with Steve's comments, I would also use stainless baffles. If using cladding ensure it is clad on the amine face.

 

[strider6]

http://www.gastreating.com/pdf/Hc Processing Apr-May 1993.pdf

S

Corrosion Prevention & Corrosion Control

 

[Corgas]

CoCorrosion:

Hope this helps.