H2S CONTENT - NACE MATERIAL?

[rogervm]

If you have a liquid service, with some quantity of H2S present, How to know when this materials have to meet the NACE requirements?

If you have the ppm of H2S and design pressure, There is any figure or table into the NACE Standard that show you the SSC region?

I found the figure 1 and figure 2 into a NACE MR0175-91, but I can not find them in the NACE MR0175/ISO 15156 2003. Are these figures the right ones for the case I'm asking?

 

[0707]

See the API bellow maybe it helps your doubts

Damage Mechanisms Affecting
Fixed Equipment in the
Refining Industry
Downstream Segment
RECOMMENDED PRACTICE 571
FIRST EDITION, DECEMBER 2003

 

[dcasto]

The latest versions of Nace0175 have changed and now they recommend more carbon steel than before.

The 2003 edition of NACE restricts the use of austenitic stainless steel alloys (e.g. 316 and 304 stainless steel) to sulfur free environments and to H2S partial pressure less than 15 psia (psi absolute) with no restriction on chlorides and temperatures to 140°F and a second provision to 50 psia for chloride contents below 50 mg/L .

 

[SJones]

For carbon steel, the figure you are seeking is contained in ISO 15156-2 on page 9. Thereafter, clause C.2 in Annex C of the same standard will help you with your liquid system.

Steve Jones
Materials & Corrosion Engineer

http://www.pdo.co.om/pdo/