Valves in Amine Unit

[ChihebG]

Experts,
What is the best material to select for valves in a CO2 Capture Amine Unit (H2S free) especially for rich and lean amine services ?

Regards,

 

[hsbcn]

Generally speaking, 300 series steel is sufficient for Amine service, but this depends on the operating parameters. Specifically, pressure, temperature and the type of amine (MEA, DGA, DIPA, MDEA or DEA) as well as a possible build-up of heat stable amine salts which can accelerate corrosion through the release of CO2. Please share details of your process.

I work with valves in exotic alloys at alloy-valves.com. This is me on Twitter and LinkedIn. Let's connect!

 

[gerhardl]

In addition: Are you also asking for sealing material? In any case, deatails as hsbcn is aking for, must be given.

Temperature ia also important, especilly if exposed below zero. If inner metal parts are wetted, it could be wise to 'upgrade' the material of the inner parts (trim) of the valve if body is selected from the 'cheaper' end of the material scale.

Seen from European side the 1,4571/SS316Ti could be a good choice. (To be checked against your details!)

 

[ChihebG]

Thank you gerhardl for your advices.

We are working on the material selection of a CO2 capture Amine unit.( Feed gas content: 76 % hydrogen and 16 % CO2 free from H2S and chlorides).

Max temperature of rich amine is 119°C and rich Amine is 106°C.
Amine used: 40 wt% MDEA, 5 wt% DEDA, and 55 wt% water.

We are selecting materials for control valves. I decided to select SS grade 304 for valves as there is no need to upgrade to duplex SS as there is no risk of SSC but I may consider 316 for more security.

I would be grateful if you can give me more advices

 

[ChihebG]

Thank you hsbcn also.

 

[gerhardl]

Warning 1: I have no practical experience for your application, but for fluids exactly as described you seem to be backed up by material selection tables in my library. PTFE sealings? Warning 2: In my practical experience 'fluids free of something' can be read as 'sometimes surprisingly also containing....!

 

[MickMc]

Typically I have seen Lean & Rich Amine Service material selection being Killed Carbon Steel with Rich being to NACE and valve trim 316 Stainless Steel.

 

[ChihebG]

thank you for your advices.