Scale‑fragment formation impairing geothermal energy production: interacting H2S corrosion and CaCO3 crystal growth: interacting H2S corrosion and CaCO3 crystal growth

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Abstract

Background: Mineral precipitates (scaling) from deep saline thermal waters often constitute a major problem during geothermal energy production. The occurrence of scale-fragments accumulating and clogging pipes, filters, and heat exchangers is of particular concern regarding an efficient energy extraction. Methods: Carbonate scale-fragments from different sections of two geothermal power plants were collected and studied in a high-resolution scaling forensic approach comprising of microstructural characterization, elemental mapping, and stable carbon and oxygen isotope transects. The solid-phase analyses were evaluated in the context of natural environmental and technical (man-made) production conditions. Results and discussion: Our results indicate an interaction of metal sulfide mineral layers mainly from H2S corrosion of the steel pipes and CaCO3 nucleation and crystal growth. A conceptual model of scale-fragment development addresses the relevance of two key interfaces: 1) the corrosion layer between the steel substrate and calcite scale and 2) the scale surface versus thermal fluid flow. The corrosion products constitute an attractive crystallization substrate of brittle and mechanically weak consistency. A rough carbonate scale surface tends to induce (micro) turbulences and increased flow resistance (frictional forces). These factors promote partial exfoliation, scale-fragment mobilization, and rapid clogging. This investigation highlights the potential of detailed petrographic and geochemical analyses of mineral precipitates for evaluating favorable versus unfavorable processes in geotechnical environmental settings.

Original languageEnglish
Article number4
Pages (from-to)1-19
JournalGeothermal Energy
Volume5
DOIs
Publication statusPublished - 1 Dec 2017

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Geothermal energy
geothermal energy
Crystal growth
corrosion
crystal
Corrosion
Precipitates
Carbonates
mineral
Minerals
pipe
steel
Geothermal power plants
Sulfide minerals
carbonate
substrate
geothermal power
thermal water
Calcite
Steel pipe

Keywords

    Fields of Expertise

    • Advanced Materials Science

    Cite this

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    title = "Scale‑fragment formation impairing geothermal energy production: interacting H2S corrosion and CaCO3 crystal growth: interacting H2S corrosion and CaCO3 crystal growth",
    abstract = "Background: Mineral precipitates (scaling) from deep saline thermal waters often constitute a major problem during geothermal energy production. The occurrence of scale-fragments accumulating and clogging pipes, filters, and heat exchangers is of particular concern regarding an efficient energy extraction. Methods: Carbonate scale-fragments from different sections of two geothermal power plants were collected and studied in a high-resolution scaling forensic approach comprising of microstructural characterization, elemental mapping, and stable carbon and oxygen isotope transects. The solid-phase analyses were evaluated in the context of natural environmental and technical (man-made) production conditions. Results and discussion: Our results indicate an interaction of metal sulfide mineral layers mainly from H2S corrosion of the steel pipes and CaCO3 nucleation and crystal growth. A conceptual model of scale-fragment development addresses the relevance of two key interfaces: 1) the corrosion layer between the steel substrate and calcite scale and 2) the scale surface versus thermal fluid flow. The corrosion products constitute an attractive crystallization substrate of brittle and mechanically weak consistency. A rough carbonate scale surface tends to induce (micro) turbulences and increased flow resistance (frictional forces). These factors promote partial exfoliation, scale-fragment mobilization, and rapid clogging. This investigation highlights the potential of detailed petrographic and geochemical analyses of mineral precipitates for evaluating favorable versus unfavorable processes in geotechnical environmental settings.",
    keywords = "Geochemie, Geothermie, Mineralogie",
    author = "Ronny Boch and Albrecht Leis and Edith Haslinger and Goldbrunner, {Johann Emmerich} and Florian Mittermayr and Heinz Fr{\"o}schl and Dorothee Hippler and Martin Dietzel",
    year = "2017",
    month = "12",
    day = "1",
    doi = "10.1186/s40517-017-0062-3",
    language = "English",
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    pages = "1--19",
    journal = "Geothermal Energy",
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    TY - JOUR

    T1 - Scale‑fragment formation impairing geothermal energy production: interacting H2S corrosion and CaCO3 crystal growth

    T2 - interacting H2S corrosion and CaCO3 crystal growth

    AU - Boch, Ronny

    AU - Leis, Albrecht

    AU - Haslinger, Edith

    AU - Goldbrunner, Johann Emmerich

    AU - Mittermayr, Florian

    AU - Fröschl, Heinz

    AU - Hippler, Dorothee

    AU - Dietzel, Martin

    PY - 2017/12/1

    Y1 - 2017/12/1

    N2 - Background: Mineral precipitates (scaling) from deep saline thermal waters often constitute a major problem during geothermal energy production. The occurrence of scale-fragments accumulating and clogging pipes, filters, and heat exchangers is of particular concern regarding an efficient energy extraction. Methods: Carbonate scale-fragments from different sections of two geothermal power plants were collected and studied in a high-resolution scaling forensic approach comprising of microstructural characterization, elemental mapping, and stable carbon and oxygen isotope transects. The solid-phase analyses were evaluated in the context of natural environmental and technical (man-made) production conditions. Results and discussion: Our results indicate an interaction of metal sulfide mineral layers mainly from H2S corrosion of the steel pipes and CaCO3 nucleation and crystal growth. A conceptual model of scale-fragment development addresses the relevance of two key interfaces: 1) the corrosion layer between the steel substrate and calcite scale and 2) the scale surface versus thermal fluid flow. The corrosion products constitute an attractive crystallization substrate of brittle and mechanically weak consistency. A rough carbonate scale surface tends to induce (micro) turbulences and increased flow resistance (frictional forces). These factors promote partial exfoliation, scale-fragment mobilization, and rapid clogging. This investigation highlights the potential of detailed petrographic and geochemical analyses of mineral precipitates for evaluating favorable versus unfavorable processes in geotechnical environmental settings.

    AB - Background: Mineral precipitates (scaling) from deep saline thermal waters often constitute a major problem during geothermal energy production. The occurrence of scale-fragments accumulating and clogging pipes, filters, and heat exchangers is of particular concern regarding an efficient energy extraction. Methods: Carbonate scale-fragments from different sections of two geothermal power plants were collected and studied in a high-resolution scaling forensic approach comprising of microstructural characterization, elemental mapping, and stable carbon and oxygen isotope transects. The solid-phase analyses were evaluated in the context of natural environmental and technical (man-made) production conditions. Results and discussion: Our results indicate an interaction of metal sulfide mineral layers mainly from H2S corrosion of the steel pipes and CaCO3 nucleation and crystal growth. A conceptual model of scale-fragment development addresses the relevance of two key interfaces: 1) the corrosion layer between the steel substrate and calcite scale and 2) the scale surface versus thermal fluid flow. The corrosion products constitute an attractive crystallization substrate of brittle and mechanically weak consistency. A rough carbonate scale surface tends to induce (micro) turbulences and increased flow resistance (frictional forces). These factors promote partial exfoliation, scale-fragment mobilization, and rapid clogging. This investigation highlights the potential of detailed petrographic and geochemical analyses of mineral precipitates for evaluating favorable versus unfavorable processes in geotechnical environmental settings.

    KW - Geochemie

    KW - Geothermie

    KW - Mineralogie

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    U2 - 10.1186/s40517-017-0062-3

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    JO - Geothermal Energy

    JF - Geothermal Energy

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    ER -