6Mo vs SDSS for produced water injection pumps

[midris]

Hello,

Client requirement for produced water re-injection pumps with the following process conditions and parameters is 6Mo super austenitic:

temperature: ~ 70 degC
pressure: ~ 200 barg
chlorides: 157000 mg/l
H2S: 24 mg/l
CO2: 650 mg/l

One supplier has stated that SDSS is better suited to this application. I have done some research into the corrosive resistance of both metals and I am unable to determine which is better suited, however, my understanding is that 6Mo is better suited in cases featuring such high chloride contents.

Would greatly appreciate your valuable feedback.

 

[midris]

I would also like to add that whether 6Mo would be better suited than SDSS taking into account the high operating temperature. My understanding is that SDSS would be ideal below 30 degC

 

[SJones]

30 deg C is for seawater. It doesn't apply to oxygen free produced water. API 610 and ISO 21457 will push you towards the super duplex option, but the client has asked for 6Mo. Who calls the shots?

Steve Jones
Materials & Corrosion Engineer

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

All answers are personal opinions only and are in no way connected with any employer.

 

[pradipgoswami]

Hi Steve,

API-610 Appendix-G, specifies:-For seawater, produced water, formation water and brine services, the purchaser and the vendor should agree on the construction
materials that best suit the intended use.

DSS & SDSS are listed as materials of construction in Appendix-H, Table-H1.However the chioce for "Super Austenitc" is also provided in the same appendix of API-610.

If you go through the following document(page15 & 16)the choice between 6 Mo and SDSS 2507 is almost close. SDSS is an excellent material with comparable CPT and CCT to that of 6Mo alloy. However properties of cast SDSS 2507 may not be always good. This may influence clients to opt for 6Mo, though cost and materials savings wise it may not be a match for SDSS.

Thanks

http://www.imoa.info/_files/stainless_steel/Duplex_Stainless_Steel_2d_Edition.pdf

Pradip Goswami,P.Eng.IWE
Welding & Metallurgical Specialist
Ontario, Canada.
ca.linkedin.com/pub/pradip-goswami/5/985/299

 

[SJones]

The best document is probably NiDI 11004

http://www.nickelinstitute.org/en/T...neWaterDesalinationandOilfieldBrinePumps.aspx

API 610 actually does not appear to address high alloy austenitics (HAA). Note c to Table H.1 defines the types of 'AUS' steels referred to. ISO 21457 also does not offer HAA as a selection choice.

Steve Jones
Materials & Corrosion Engineer

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

All answers are personal opinions only and are in no way connected with any employer.

 

[midris]

Thank you Gentlemen for your response.

Mr. Jones,

If 6Mo is better suited than super duplex at high temperature brine applications, wouldn't that also be the case for oxygen free produced water as well? Or does the added factor of sour service make super duplex the better option?

Thanks,
midris

 

[SJones]

Not if you are bound to strictly follow the environmental limits of ISO 15156-3 with the conditions that you have quoted in your original post. Try comparing Table A.8 with Technical Circular 1, Table A.24.

Steve Jones
Materials & Corrosion Engineer

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

All answers are personal opinions only and are in no way connected with any employer.