What is the ASME definition of Sour Gas?

Thanks,

QCMike

QCmike,

ASME Code does not define Sour Gas. I remember there is a NACE standard which gives a definition.

However, in real life Sour gas is a crude natural gas, mainly consisting of Methane and CO2, but with H2S contents, which makes the gas poisonous, corrosive and combstible.

A vessel for sour gas should be specified for Lethal Service. In Section VIII this mandates PWHT (for CS) and full RT.

DK

Requirement of equipment in sour service are covered in NACE MR 0175/ ISO 15156 (Materials for use in H2S containing environment).

Not all the process media containg H2S are considered as considered as lethal. This depends on H2S concentration and the H2S partial pressure in the process media whether to call the system as sour/ Lethal.

H2S itself is not combustible although it is poisonous. H2S alone is not corrosive but in a wet system with water it becomes corrosive.

Crude oil storage with an absolute pressure of 65 psi is permitted exclusion from sour service requirement in NACE.

H2S partial pressure of 0.5 psi in gaseous system do not required to be classified under sour service as per NACE.

Sour service requirements are further classified in various category in NACE based on H2S partial pressure in the process system.

Regards

Hi All,

I am not posting any reply to this topic, but raising a new query on the subject being discussed in this topic. So, please execuse me in case i have caused any confusion.

Apart from the NACE sandard MR-0175 that Sanjeev has talked in the response below, there is one more relatively new standard MR-0103, which is applicable specifically to refinery equipment.

Has anybody got any experience on the latter standard?
Can the forum help let me know the basic diff. between the two standards.
I wanna know the impications of selecting MR-0175 instead of MR-0103 for equipment subject to sour service.How big the change in metallurgy shall be?

[url]http://www.documentation.frco.com/groups/public/documents/articles_articlesreprints/nace_overview_corrosion2004.pdf[/url]

[url]http://www.documentation.frco.com/groups/public/documents/articles_articlesreprints/nace_standard_mr103_bush.pdf[/url]

[url]http://committees.api.org/standards/CRE/scop/mtginfo/docs/A7NACEMR0103Presentation.pdf[/url]
Hope these articles will help

Regards

hey...
A state of matter tht has neither a definte shape or volume. In other words, it can take up as much space as it have to do do and can be any shape it takes up (like a liquid but without a definite volume.)

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