Plate Material best suited for H2S applications 1

[mechatronic]

Please brief H2S corrosion resistant material for pressure vessel.

Thanks a lot

 

[CoryPad]

ISO 15156 covers this in great detail:

http://www.nace.org/nacestore/produ...MR0175/ISO+15156+Petroleum,+Petrochemical+and

Regards,

Cory

Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.

 

[mechatronic]

Corypad, Thanks a lot. But could you please give a general idea which ASTM material suited . Only an outline is fine .. It will be of great help

thank you

 

[mechatronic]

Again, I think NACE TM 0284 deals with Pressure vessel material specifically ?

I dont have copy of NACE TM 0284 - Does it specify any ASTM material for H2S corrosion for pressure vessels?

 

[CoryPad]

Why do you need something from ASTM International? I don't think they have anything directly related to this subject. Anyone who works with H₂S environments uses the NACE/ISO documents. Both pressure vessels and H₂S environments require specialized information and technology, so you need to go to the appropriate sources.

Regards,

Cory

Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.

 

[SJones]

TM0284 is a test method for assessing the resistance to HIC. It will not state any specific materials. The question is far too vague to give any realistic answer. There are several forms of corrosion that can occur in H2S containing environments dependent upon the material, temperature, chloride content, partial pressure of H2S, amongst others (one being whether liquid water is present). More information regarding process conditions is required for a start; followed by the perception of risk associated with operating the vessel and whether you are capital expenditure driven or wish to work on a lifecycle cost basis.

Steve Jones
Materials & Corrosion Engineer

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

 

[rorschach]

NACE MR0175 covers H2S is sour gas service and has recommendations based on specific application and H2S partial pressure. Generally speaking, for carbon steel, the hardness must be below 22 HRC, the nickel must be below I think 2%, sulphur, and phosphorus should be essentially nil (as low as possible). Any free-machining grade is verboten. For pressure vessel service that may see elevated temp excursions, you'll need the carbon to be low to keep the steel from hardening and becoming susceptible to H2S embrittlement.

ASTM A516 Gr 70 is a good, low carbon, fine grain all around choice. ASTM 515 Gr 70 and ASTM A285 are also possibles too but A516 is generally stronger and has a finer grain which is good for toughness. A515 is coarser grained and that is good for high temp creep. All three are intended for pressure vessel service.

All of the above however have around .15 to .30 silicon in them though and I can't recall off the top of my head what the NACE MR0175 limits are for silicon, that might take them out of the running.

 

[kenvlach]

I like SJones' comment: "The question is far too vague to give any realistic answer."

I've purchase pure (well, 99.5%) H₂S (liquified gas) for research; it came in aluminum gas cylinders.

 

[mechatronic]

rorschach (Petroleum),

Excellent tip Rorsachach. Thanks a lot . In fact I have come across ASTM 516 Gr 70 many times but still was not sure to substantiate the selection.

Thanks a lot for the practical tip

Regards,

Mechatronic

 

[SJones]

So now you have selected A516 Gr 70 what are you going to specify for corrosion allowance and HIC resistance?

Steve Jones
Materials & Corrosion Engineer

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

 

[spayette]

Through our experience we have found that ASTM A-516 Gr. 60N is more resistant to cracking than Gr. 70 material because of the lower tensile strength and, as such, has become the material of choice for moderate exposure. Of course, PWHT of the vessel is also a requirement when this material is used.

For more severe H2S environments gunite lining, stainless steel clad plate, etc. may be required.