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<p>Geothermal heat exchangers (GHXs) are essential in binary Organic Rankine Cycle (ORC) plants and ground-source systems but suffer significant performance degradation due to scaling, fouling, and corrosion caused by aggressive geothermal brines. Silica and carbonate scaling can reduce heat transfer capacity by 30–50%, while carbon steel components exhibit corrosion rates of 0.1–0.4&#xa0;mm/y in chloride-rich environments. Fouling behaviour follows an asymptotic, linear, or falling-rate trend, depending on whether crystallisation is diffusion- or reaction-controlled, thereby significantly affecting thermal resistance and pressure drop. This review evaluates degradation mechanisms and mitigation strategies, including chemical and mechanical descaling, corrosion-resistant alloys (PREN &gt; 40), and advanced coatings. Thermal spray coatings (e.g., WC-CoCr, TiO<sub>2</sub>) enhance erosion–corrosion resistance and improve heat transfer performance, while PECVD and liquid-phase deposited oxide coatings provide conformal antifouling protection and extended service intervals. A hybrid approach combining corrosion-resistant alloys with engineered surface coatings is identified as the most promising pathway to reduce oversizing, extend service life, and improve the economic viability of geothermal plants.</p>

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Advanced materials and surface engineering strategies for mitigating fouling and corrosion in geothermal heat exchangers

  • 期刊论文

  • 出版模式：

    开放获取

  • 发表日期：

    2026年5月28日

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  • Md Atiqur Rahman,
  • S. M. Mozammil Hasnain,
  • Prabhu Paramasivam,
  • Abinet Gosaye Ayanie

摘要

Geothermal heat exchangers (GHXs) are essential in binary Organic Rankine Cycle (ORC) plants and ground-source systems but suffer significant performance degradation due to scaling, fouling, and corrosion caused by aggressive geothermal brines. Silica and carbonate scaling can reduce heat transfer capacity by 30–50%, while carbon steel components exhibit corrosion rates of 0.1–0.4 mm/y in chloride-rich environments. Fouling behaviour follows an asymptotic, linear, or falling-rate trend, depending on whether crystallisation is diffusion- or reaction-controlled, thereby significantly affecting thermal resistance and pressure drop. This review evaluates degradation mechanisms and mitigation strategies, including chemical and mechanical descaling, corrosion-resistant alloys (PREN > 40), and advanced coatings. Thermal spray coatings (e.g., WC-CoCr, TiO2) enhance erosion–corrosion resistance and improve heat transfer performance, while PECVD and liquid-phase deposited oxide coatings provide conformal antifouling protection and extended service intervals. A hybrid approach combining corrosion-resistant alloys with engineered surface coatings is identified as the most promising pathway to reduce oversizing, extend service life, and improve the economic viability of geothermal plants.