Thu, 07 November, 2024
Findings from the TWI-assisted, EU-funded GeoSmart project have been published as a paper in the Journal of Materials.
The paper, ‘Investigation of Scaling and Materials’ Performance in Simulated Geothermal Brine,’ was co-authored by TWI Ltd’s David Martelo, Briony Holmes, Namrata Kale and Shiladitya Paul alongside Samuel Warren Scott from the University of Iceland’s Institute of Earth Sciences.
The findings in the paper come from a larger GeoSmart investigation to create a scaling retention system for the Kizildere 2 geothermal power plant in Turkey, with the wider aim of improving the flexibility and efficiency of geothermal heat and power systems.
Geothermal Corrosion and Scaling Challenges
Geothermal energy solutions promise a sustainable and eco-friendly form of power generation, but the efficiency and lifespan of geothermal power plants are frequently compromised by corrosion and scaling issues. Corrosion can occur as a result of selecting the wrong materials or from changes in the geothermal brine’s chemistry. Scaling occurs when dissolved minerals are precipitated from the geothermal fluid and deposited on the surfaces of pipes and equipment, causing blockages and increasing maintenance costs.
Mitigating against Scaling and Corrosion
There is a variety of mitigation techniques in use currently against geothermal scaling. These include chemical treatments that slow the scale deposition rate and methods to control fluid temperatures. Coatings that help materials to resist scaling have also shown promise, but the methods in use can create other issues of their own. For example, the use of scaling inhibitors can cause corrosion or stress corrosion cracking.
The Study
This study presented in the published paper explores the behaviour of materials in a simulated geothermal brine using flow conditions that approximate the predicted flow conditions within the geothermal brine. The investigation used a laboratory vessel that was designed to replicate the wall shear stress conditions in a scaling reactor to test both scale-promoting and scale-preventing materials.
The tested materials, including carbon steel, austenitic stainless steel, duplex stainless steel, two proprietary two-part epoxy coatings, and thermally sprayed aluminium (TSA), showed varying scaling tendencies as well as minimal corrosion.
Coupons of the materials that were tested have now been introduced into a retention tank installed at Kizildere 2 so they can be assessed and compared to the laboratory findings.
Find Out More
You can find out more about the materials and the testing conditions as well as the findings of this work by reading the full paper, here: https://doi.org/10.3390/ma17215250
You can find out more about the GeoSmart project by visiting the dedicated project website, here: https://www.geosmartproject.eu/
The GeoSmart project has received funding from the European Union's Horizon 2020 research and innovation programme. Grant agreement 818576