Best Material for a gas containing high CO2 1

[ChemE2912]

Hello!

We are designing a new unit for recovering liquid hydrocarbons from a gas stream, which has a CO2 content of 10% molar.

The stream is taken downstream from a gas dehydration (Tri-ethylene glycol) unit, and the water content of this stream is 12 lb/MMSCF of gas.

The system pressure is about 1600 psig, and therefore the partial pressure of the CO2 in the stream is high (160 psig).

Due to this high CO2 partial pressure, and the presence of this water content on the stream, are we required to use Stainless Steel, or can we use Carbon Steel??

Is there any paper/book/reference/website where I can look further in this topic?

Any help is very well appreciated.

Regards,

ChemE2912

 

[metengr]

ChemE2912;
Could you provide more information on service temperature and the role of water in the process. If the water exists as vapor with the C02, carbon steel could be used provided service temperatures are below 700 deg F.

I have seen corrosion data for carbon steel exposed to C02 dissolved in water. The corrosion rate increases as the partial pressure of C02 increases. However, this is for an aqueous condition, which may not apply to your situation.

 

[ChemE2912]

Thanks Metengr,

The process is aimed to recover liquids (C5+) from a gas stream. Therefore, we are attempting to expand the gas and cool it down to condense these liquids. In some circumnstances, where free water may be present, according to our simulator, we have the concern that SS instead of CS may be required.

In such cases, do we need to go to SS or can we still use CS?

Regards,

ChemE2912

 

[metengr]

Based on your post, I would agree and go with a 304L stainless steel pipe material to avoid any risk of internal wastage from corrosion with water and the high partial pressure of C02.