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| Titel |
Ripple scalings in geothermal facilities, a key to understand the scaling process |
| VerfasserIn |
Bernhard Kohl, James Grundy, Thomas Baumann |
| Konferenz |
EGU General Assembly 2017
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| Medientyp |
Artikel
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| Sprache |
en
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 19 (2017) |
| Datensatznummer |
250139939
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| Publikation (Nr.) |
 EGU/EGU2017-3261.pdf |
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| Zusammenfassung |
| Scalings are a widespread problem among geothermal plants which
exploit the Malm Aquifer in the Bavarian Molasse Zone. They
effect the technical and economic efficiency of geothermal
plants.
The majority of the scalings observed at geothermal facilities
exploring the Malm aquifer in the Bavarian Molasse Basin are
carbonates. They are formed due to a disruption of the
lime-carbonic-acid equilibrium during production caused by
degassing of CO2. These scalings are found in the production
pipes, at the pumps and at filters and can nicely be described
using existing hydrogeochemical models. This study proposes a
second mechanism for the formation of scalings in ground-level
facilities.
We investigated scalings which accumulated at the inlet to the
heat exchanger. Interestingly, the scalings were recovered after
the ground level facilities had been cleaned.
The scalings showed distinct ripple structures, which is likely a
result of solid particle deposition. From the ripple features the
the flow conditions during their formation were calculated based
on empirical equations (Soulsby, 2012).
The calculations suggest that the deposits were formed during
maintenance works. Thin section images of the sediments indicate
a two-step process: deposition of sediment grains, followed by
stabilization with a calcite layer. The latter likely occured
during maintenance.
To prevent this type of scalings blocking the heat exchangers,
the maintenance procedure has to be revised.
References:
Soulsby, R. L.; Whitehouse, R. J. S.; Marten, K. V.: Prediction of time-evolving sand ripples in shelf seas. Continental Shelf Research 2012, 38, 47-62 |
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