Hydrochemical and operational parameters driving carbonate scale kinetics at geothermal facilities in the Bavarian Molasse Basin
Abstract The majority of scales observed at geothermal facilities exploring the Malm Aquifer in the Bavarian Molasse Basin are carbonates. They form due to a disruption of the lime–carbonic acid equilibrium during production caused by a reduction of the partial pressure of carbon dioxide due to pres...
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Springer Science and Business Media LLC
2020
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Online Access: | http://dx.doi.org/10.1186/s40517-020-00180-x https://link.springer.com/content/pdf/10.1186/s40517-020-00180-x.pdf https://link.springer.com/article/10.1186/s40517-020-00180-x/fulltext.html |
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crspringernat:10.1186/s40517-020-00180-x 2023-05-15T15:53:05+02:00 Hydrochemical and operational parameters driving carbonate scale kinetics at geothermal facilities in the Bavarian Molasse Basin Köhl, Bernhard Elsner, Martin Baumann, Thomas Bayerisches Staatsministerium für Bildung und Kultus, Wissenschaft und Kunst 2020 http://dx.doi.org/10.1186/s40517-020-00180-x https://link.springer.com/content/pdf/10.1186/s40517-020-00180-x.pdf https://link.springer.com/article/10.1186/s40517-020-00180-x/fulltext.html en eng Springer Science and Business Media LLC https://creativecommons.org/licenses/by/4.0 https://creativecommons.org/licenses/by/4.0 CC-BY Geothermal Energy volume 8, issue 1 ISSN 2195-9706 Economic Geology Geotechnical Engineering and Engineering Geology Renewable Energy, Sustainability and the Environment journal-article 2020 crspringernat https://doi.org/10.1186/s40517-020-00180-x 2022-01-04T15:15:50Z Abstract The majority of scales observed at geothermal facilities exploring the Malm Aquifer in the Bavarian Molasse Basin are carbonates. They form due to a disruption of the lime–carbonic acid equilibrium during production caused by a reduction of the partial pressure of carbon dioxide due to pressure change and degassing. These scales are found at the pumps, production pipes, filters, heat exchangers, and occasionally in the injection pipes. In this study, scales of all sections of geothermal facilities were taken. The database consists of scale samples from 13 geothermal pumps, 6,000 m production pipe (sample interval 10 - 12 m), 11 heat exchanger revisions, 2 injection pipes, and numerous filter elements. The samples were analyzed by SEM-EDX, XRD, Raman spectroscopy, and acid digestion to assess their chemical and mineralogical composition. From direct gauge measurements at six facilities during pump changes, scale rates were determined along the production pipes. From indirect measurements (multifinger caliper measurements) scale rates are derived for the region below the pump. Hydrochemical analyses from the wellhead were taken from 13 sites to feed the hydrogeochemical models. The calcite scale rates in the production pipes increase from the pump to the wellhead, where they reach 1.5 - 4.1 $$\mu$$ μ mol/( $$\hbox {m}^2\,\cdot$$ m 2 · s). Scale rates below the pump reach up to 1.5 $$\mu$$ μ mol/( $$\hbox {m}^2\,\cdot$$ m 2 · s). Given the slight change of hydrochemistry on the rise through the production pipe, where < 4 % of dissolved calcium ions precipitate as scale, scale rates cannot be derived from water samples at the wellhead, but require direct gauge measurements. The small amount of precipitation, together with fully turbulent conditions suggests that all measured rates are controlled by the surface-reaction of calcite crystallization following the nomenclature of Appelo and Postma (2004). Two approaches are used for the modeling of the scale rates. The first approach is based on hydrogeochemical modeling with PHREEQC. Scale rates calculated by this method are one order of magnitude higher than the measured ones. The second approach is based on correlations between the measured scale rates at the wellhead at six facilities and identified thermodynamic scale drivers ( $$\Delta$$ Δ log (p $$\hbox {CO}_2$$ CO 2 ), $$\Delta$$ Δ total pressure, $$\Delta$$ Δ pH, and $$\hbox {SI}_{{calcite}}$$ SI calcite ). The correlations allow linear regressions which are used for the prediction of the scale rate at the wellhead, along the whole production pipe, and below. The modeling results show that scale prediction based on the new regressions that rely on thermodynamic scale drivers works better than existing hydrogeochemical models, already without implementation of kinetic parameters ( $$\hbox {CO}_2$$ CO 2 -stripping and magnesium inhibition). Article in Journal/Newspaper Carbonic acid Springer Nature (via Crossref) Malm ENVELOPE(12.222,12.222,65.323,65.323) Geothermal Energy 8 1 |
institution |
Open Polar |
collection |
Springer Nature (via Crossref) |
op_collection_id |
crspringernat |
language |
English |
topic |
Economic Geology Geotechnical Engineering and Engineering Geology Renewable Energy, Sustainability and the Environment |
spellingShingle |
Economic Geology Geotechnical Engineering and Engineering Geology Renewable Energy, Sustainability and the Environment Köhl, Bernhard Elsner, Martin Baumann, Thomas Hydrochemical and operational parameters driving carbonate scale kinetics at geothermal facilities in the Bavarian Molasse Basin |
topic_facet |
Economic Geology Geotechnical Engineering and Engineering Geology Renewable Energy, Sustainability and the Environment |
description |
Abstract The majority of scales observed at geothermal facilities exploring the Malm Aquifer in the Bavarian Molasse Basin are carbonates. They form due to a disruption of the lime–carbonic acid equilibrium during production caused by a reduction of the partial pressure of carbon dioxide due to pressure change and degassing. These scales are found at the pumps, production pipes, filters, heat exchangers, and occasionally in the injection pipes. In this study, scales of all sections of geothermal facilities were taken. The database consists of scale samples from 13 geothermal pumps, 6,000 m production pipe (sample interval 10 - 12 m), 11 heat exchanger revisions, 2 injection pipes, and numerous filter elements. The samples were analyzed by SEM-EDX, XRD, Raman spectroscopy, and acid digestion to assess their chemical and mineralogical composition. From direct gauge measurements at six facilities during pump changes, scale rates were determined along the production pipes. From indirect measurements (multifinger caliper measurements) scale rates are derived for the region below the pump. Hydrochemical analyses from the wellhead were taken from 13 sites to feed the hydrogeochemical models. The calcite scale rates in the production pipes increase from the pump to the wellhead, where they reach 1.5 - 4.1 $$\mu$$ μ mol/( $$\hbox {m}^2\,\cdot$$ m 2 · s). Scale rates below the pump reach up to 1.5 $$\mu$$ μ mol/( $$\hbox {m}^2\,\cdot$$ m 2 · s). Given the slight change of hydrochemistry on the rise through the production pipe, where < 4 % of dissolved calcium ions precipitate as scale, scale rates cannot be derived from water samples at the wellhead, but require direct gauge measurements. The small amount of precipitation, together with fully turbulent conditions suggests that all measured rates are controlled by the surface-reaction of calcite crystallization following the nomenclature of Appelo and Postma (2004). Two approaches are used for the modeling of the scale rates. The first approach is based on hydrogeochemical modeling with PHREEQC. Scale rates calculated by this method are one order of magnitude higher than the measured ones. The second approach is based on correlations between the measured scale rates at the wellhead at six facilities and identified thermodynamic scale drivers ( $$\Delta$$ Δ log (p $$\hbox {CO}_2$$ CO 2 ), $$\Delta$$ Δ total pressure, $$\Delta$$ Δ pH, and $$\hbox {SI}_{{calcite}}$$ SI calcite ). The correlations allow linear regressions which are used for the prediction of the scale rate at the wellhead, along the whole production pipe, and below. The modeling results show that scale prediction based on the new regressions that rely on thermodynamic scale drivers works better than existing hydrogeochemical models, already without implementation of kinetic parameters ( $$\hbox {CO}_2$$ CO 2 -stripping and magnesium inhibition). |
author2 |
Bayerisches Staatsministerium für Bildung und Kultus, Wissenschaft und Kunst |
format |
Article in Journal/Newspaper |
author |
Köhl, Bernhard Elsner, Martin Baumann, Thomas |
author_facet |
Köhl, Bernhard Elsner, Martin Baumann, Thomas |
author_sort |
Köhl, Bernhard |
title |
Hydrochemical and operational parameters driving carbonate scale kinetics at geothermal facilities in the Bavarian Molasse Basin |
title_short |
Hydrochemical and operational parameters driving carbonate scale kinetics at geothermal facilities in the Bavarian Molasse Basin |
title_full |
Hydrochemical and operational parameters driving carbonate scale kinetics at geothermal facilities in the Bavarian Molasse Basin |
title_fullStr |
Hydrochemical and operational parameters driving carbonate scale kinetics at geothermal facilities in the Bavarian Molasse Basin |
title_full_unstemmed |
Hydrochemical and operational parameters driving carbonate scale kinetics at geothermal facilities in the Bavarian Molasse Basin |
title_sort |
hydrochemical and operational parameters driving carbonate scale kinetics at geothermal facilities in the bavarian molasse basin |
publisher |
Springer Science and Business Media LLC |
publishDate |
2020 |
url |
http://dx.doi.org/10.1186/s40517-020-00180-x https://link.springer.com/content/pdf/10.1186/s40517-020-00180-x.pdf https://link.springer.com/article/10.1186/s40517-020-00180-x/fulltext.html |
long_lat |
ENVELOPE(12.222,12.222,65.323,65.323) |
geographic |
Malm |
geographic_facet |
Malm |
genre |
Carbonic acid |
genre_facet |
Carbonic acid |
op_source |
Geothermal Energy volume 8, issue 1 ISSN 2195-9706 |
op_rights |
https://creativecommons.org/licenses/by/4.0 https://creativecommons.org/licenses/by/4.0 |
op_rightsnorm |
CC-BY |
op_doi |
https://doi.org/10.1186/s40517-020-00180-x |
container_title |
Geothermal Energy |
container_volume |
8 |
container_issue |
1 |
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1766388141877362688 |