Material Selection for Geothermal Brine 3

[mufasa1]

Dear All,

What kind of material would you suggest for a geothermal brine which has TDS (57000) and Cl (44140) concentrations? Ph of the brine is 7.5. On the other hand it is also rich in Ca, K and Mg. Well temperature is 174 Cdeg. Surface temperature is around 150 Cdeg.

I have reviewed some documents of Sandvik's dublex stainless steel especially for seawater service. Exotic materials like dublex stainless steel for steamfield piping is very pricy.

At geothermal pipelines, silica depoits form in time. Isn't this silica deposition protective against corrosion? Doesn't it act like a protective layer in the pipe. (Please note that we will inhibit chemicals in the well to disable severe deposition)

Looking forward to your comments,

Best Regards,

 

[strider6]

MATERIALS SELECTION GUIDELINES
FOR GEOTHERMAL POWER SYSTEM

http://www.osti.gov/energycitations/servlets/purl/6356102-P6Q504/

COMPANION STUDY GUIDE
TO
SHORT COURSE ON GEOTHERMAL CORROSION
AND MITIGATION IN LOW TEMPERATURE
GEOTHERMAL HEATING SYSTEMS

http://www.osti.gov/geothermal/servlets/purl/894036-6X5f9k/894036.pdf

CORROSION BEHAVIOR OF MATERIALS EXPOSED TO
HYPERSALINE GEOTHERMAL BRINE

http://www.osti.gov/bridge/servlets/purl/6664773-3YfNAO/6664773.PDF

AN EVALUATION OF MATERIALS FOR SYSTEMS
USING COOLED, TREATED GEOTHERMAL OR
HIGH-SALINE BRINES

http://www.osti.gov/energycitations/servlets/purl/6918703-xi8D2F/6918703.PDF

ADDENDUM TO MATERIAL SELECTION GUIDELINES
FOR GEOTHERMAL ENERGY UTILIZATION SYSTEMS

http://www.osti.gov/energycitations/servlets/purl/890120-e1QAdE/

hope this help
S.

Corrosion Protection & Corrosion Control

 

[EdStainless]

No the deposits don't help, they hurt. The scale formation isn't fully dense. It acts like a crevice former trapping impurities under it and accelerating corrosion.

One thing in your favor is that the brine has no oxygen in it.

Still, your only real options are high alloy stainless grades. You are probably looking at super-duplex alloys these days in terms of economics. They have high strength so you can use thinner walls, and the low Ni content keeps the price from being as high as the 6%Mo super-austenitics.

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Plymouth Tube

 

[mufasa1]

Gentlemen,

Thank you very much for your valuable input. This is for a new jeotermal power plant project in west coast of Turkiye. There are other JES Power plants in the country but they do not have such corrosive brine. They use carbon steel pipes with inhibitor system at the well.

Thanks again,

 

[rconner]

With regard to geothermal-type pipelines, I think several different (uninsulated and pre-insulated etc.) piping materials have been used over many decades of such applications, e.g. even including asbestos cement pipes. While I don’t profess a lot of direct experience in this specific application, I know that a good bit of cementlined pipes has been used in these and other salty and thermal water services, and some contemporary geothermal users (e.g.

http://geoheat.oit.edu/bulletin/bull28-2/art2.pdf

and other sites), and due in some cases to problems (not the least of which are various effects of the heat often involved) with other pipes and joints etc., have gravitated to cement mortar-lined ductile iron pipe. Care should of course be taken in the selection of gaskets, as standard SBR AWWA pipe gaskets are not rated for the extreme degree of heat often encountered in some geothermal applications. I think ductile iron geothermal systems typically employ available special rubber formulations, with adequate rating to handle the heat (such as EPDM). Finally, I think it is possible consideration of some system design and operational factors, e.g. flow velocity, control of any chemical additions, and aeration or non-aeration in periods of service or disruption etc., could also factor in along with material selection in potentially aggressive exposures.