Renewables – Geothermal

Why monitor for corrosion?

The costs of prospecting for and building a geothermal facility dwarf the costs of operating it over its 30-year life. Recovery of these up-front costs is contingent on uninterrupted operation. Minimisation of risk of interruption, including from corrosion, is particularly critical where the capex has been financed by long-term debt finance, servicing of which requires uninterrupted operating revenues.

Geothermal steam and hot water piping networks are very extensive and are typically constructed primarily of carbon steel.

Geothermal fluids – wet steam, commonly containing CO2, H2S, NH3 and chlorides – are highly corrosive. Temperatures and levels of these species are variable – and unpredictably so. Undetected internal corrosion can lead to through-wall leaks or even ruptures. Corrosion rates in carbon steel can exceed 1000 mils (mpy), or 25mm, per year in areas with high HCl content steam and acid-dewpoint corrosion.

Where to monitor for corrosion?

Continuous steam scrubbing of steam from certain wells with sodium hydroxide solutions is required to neutralize the HCl content in steam. The scrubbed steam is rendered non-corrosive to miles of carbon steel steam piping downstream.

Proving that wall thicknesses are being protected is the measure of success for a scrubbing system. Continuous monitoring of the thickness of steam wellhead tie-in piping downstream of corrosion mitigation steam scrubbing systems gives early warning of process upsets and ongoing high corrosion rates without waiting for a hole to develop. This allows for optimal design of the scrubbing system to get better contacting of scrub solution with steam.

Contact us to discuss how we can assist you

Help & Support
Need support? Here you'll find how to contact the team that can give the assistance you need.
Get help & support
© 2024 Guided Ultrasonics Ltd. All rights reserved