NACE MR 0175/ISO 15156-3 Corrigendum 2

[analyzergroup]

NACE MR 0175 2003:
4.2.2 The maximum acceptable H2S partial pressure shall be 100 kPa abs (15 psia) at a maximum temperature of 60°C (140°F), with no restrictions on chlorides, and no elemental sulfur. If the chloride content is less than 50 mg/L, the H2S partial pressure shall be less than 350 kPa abs (50 psia).

In our process we have high partial pressure of H2S (65.9x16%=10.5bar), and as per the above clause SS316 ( Tube) is not suitable.
the use of nickel based alloys, such as Inconel, Hastelloy C-276.should be good.

Further more , as per NACE Technical Corrigendum 2 to NACE MR0175/ISO 15156-3:2003 , page 5 Table A.2 & page 6, Table A.6 , we are of the opinion that SS-316 should be suitable for the application in question

does it mean that As long as temperature is below 60 Deg C & chloride content is less than 50 mg/l.SS316 is suitabel and we don’t have to worry about the with the high H2S partial pressure and just the high H2S partial pressure(10.5 bar) mandates a change in the probe/Tube material?????)

 

[SJones]

You are a little behind because ISO 15156 is now at 2009 and NACE MR0175 reached Technical Circular 2 in 2008. However, not much changed with respect to your application. Your interpretation is correct: less than 50 mg/litre of Cl- results in no restrictions on temperature and H2S partial pressure for austenitic stainless steels having the correct heat treatment and hardness.

Steve Jones
Materials & Corrosion Engineer

http://www.linkedin.com/pub/8/83b/b04