MEG Reclamation - Material Selection & Corrosion

[rscosta1976]

Good afternoon,

Please share your experiences regarding MEG reclamation units corrosion, particularly in the circuits handling MEG solution saturated with salts. Only found one paper about this (NACE 07116). Licensor is specifying all these circuits (downstream of Sour gas Stripper) in carbon steel (with 6mm CA). This includes reclaimer bottom (hot) loop and associated downstream piping and equipment.

I honestly have some concerns related with O2 ingress and with salt deposits accumulation, which may cause Carbon Steel to corrode and experience pitting.

I would appreciate if you can share your experience. Normal operating conditions are pointed below.

Solution: 90%wt MEG + 10%H2O saturated with NaCl salts.
H2S and CO2 is pointed to be 0%mol, assuming all was previous stripped in the upstream Sour Gas Stripper (through N2 injection) and on the Vacuum Reclaimer.
Temp.= 150 F to 250 F (reclaimer bottom loop)


Kind regards,

 

[Chumpes]

hello
I ve already seen CS + 6mm for this system of MEG reclaiming. MEG has corrosion inhibitor effects for carbon steel.
"salts" does really mean almost nothing to me because it exists plenty of different "salts" with different properties.

In my opinion, dissolved NaCl is not so harmful for carbon steel, but oxygen is.

Also, I save the word "pitting" for a form of localized corrosion of stainless steel. In my opinion carbon steel cannot pit because it has no passive scales : this would still be a kind of generalized corrosion of carbon steel.
Saturation of NaCl salts tends to scale metal with salt layers that limit diffusion of corrosive compounds to the metal surface.
Saturation of NaCl salts can produce particles (abrasion) and fouling (pressure drop).