Hostname: page-component-78c5997874-94fs2 Total loading time: 0 Render date: 2024-11-10T08:56:02.880Z Has data issue: false hasContentIssue false
  • English
  • Français

Microstructural and chemical variation in silica-rich precipitates at the Hellisheiði geothermal power plant

Published online by Cambridge University Press:  05 July 2018

D. B. Meier ,
E. Gunnlaugsson ,
I. Gunnarsson ,
B. Jamtveit ,
C. L. Peacock  and
L. G. Benning
D. B. Meier*
Affiliation:
Cohen Geochemistry Group, School of Earth and Environment, University of Leeds, Leeds LS2 9JT, UK
E. Gunnlaugsson
Affiliation:
Reykjavik Energy, 110 Reykjavik, Iceland
I. Gunnarsson
Affiliation:
Reykjavik Energy, 110 Reykjavik, Iceland
B. Jamtveit
Affiliation:
Physics of Geological Processes, Department of Geoscience, University of Oslo, 0316 Oslo, Norway
C. L. Peacock
Affiliation:
Cohen Geochemistry Group, School of Earth and Environment, University of Leeds, Leeds LS2 9JT, UK
L. G. Benning
Affiliation:
Cohen Geochemistry Group, School of Earth and Environment, University of Leeds, Leeds LS2 9JT, UK GFZ German Research Centre for Geosciences, Helmholz Centre Potsdam, Telegrafenberg, 14473 Potsdam, Germany
*
* E-mail: eedbm@leeds.ac.uk
Rights & Permissions [Opens in a new window]

Abstract

Core share and HTML view are not available for this content. However, as you have access to this content, a full PDF is available via the ‘Save PDF’ action button.

Precipitation of amorphous silica (SiO2) in geothermal power plants, although a common factor limiting the efficiency of geothermal energy production, is poorly understood and no universally applicable mitigation strategy to prevent or reduce precipitation is available. This is primarily due to the lack of understanding of the precipitation mechanism of amorphous silica in geothermal systems.

In the present study data are presented about microstructures and compositions of precipitates formed on scaling plates inserted at five different locations in the pipelines at the Hellisheiði power station (SW-Iceland). Precipitates on these plates formed over 6 to 8 weeks of immersion in hot (120 or 60ºC), fast-flowing and silica-supersaturated geothermal fluids (~800 ppm of SiO2). Although the composition of the precipitates is fairly homogeneous, with silica being the dominant component and Fe sulfides as a less common phase, the microstructures of the precipitates are highly variable and dependent on the location within the geothermal pipelines. The silica precipitates have grown through aggregation and precipitation of silica particles that precipitated homogeneously in the geothermal fluid. Five main factors were identified that may control the precipitation of silica: (1) temperature, (2) fluid composition, (3) fluid-flow regime, (4) distance along the flow path, and (5) immersion time.

On all scaling plates, a corrosion layer was found underlying the silica precipitates indicating that, once formed, the presence of a silica layer probably protects the steel pipe surface against further corrosion. Yet silica precipitates influence the flow of the geothermal fluids and therefore can limit the efficiency of geothermal power stations.

Keywords

silicaprecipitatesscalinggeothermal powerIceland
Type
Research Article
Information
Mineralogical Magazine , Volume 78 , Issue 6 , November 2014 , pp. 1381 - 1389
Creative Commons
Creative Common License - CCCreative Common License - BY
© [2014] The Mineralogical Society of Great Britain and Ireland. This is an open access article distributed under the terms of the Creative Commons Attribution (CC BY) licence (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 2014

References

Alexander, G. (1954) The polymerization of monosilicic acid. Journal of the American Chemical Society, 76, 2094–2096.CrossRefGoogle Scholar
Amjad, Z. and Zuhl, R. (2008) An evaluation of silica scale control additives for industrial water systems. Paper No. 08368, CORROSION Conference & Expo, NACE International, Houston, Texas, U.S.A.Google Scholar
Angcoy, E. and Arnórsson, S. (2010) An experiment on monomeric and polymeric silica precipitation rates from supersaturated solutions. Proceedings of the World Geothermal Congress, Bali, Indonesia.Google Scholar
Arnórsson, S., Bjarnason, J.O. ., Giroud, N., Gunnarsson, I. and Stefánsson, A. (2006) Sampling and analysis of geothermal fluids. Geofluids, 6, 203–216.Google Scholar
Fleming, B.A. (1986) Kinetics of reaction between silicic acid and amorphous silica surfaces in NaCl solutions. Journal of Colloid and Interface Science, 110, 40–64.CrossRefGoogle Scholar
Fleming, B. and Crerar, D. (1982) Silicic acid ionization and calculation of silica solubility at elevated temperature and pH application to geothermal fluid processing and reinjection. Geothermics, 11, 15–29.CrossRefGoogle Scholar
gallup, d.l. (2002) investigations of organic inhibitors for silica scale control in geothermal brines. geothermics, 31, 415–430.CrossRefGoogle Scholar
Gallup, D.L. and Barcelon, E. (2005) Investigations of organic inhibitors for silica scale control from geothermal brines–II. Geothermics, 34, 756–771.CrossRefGoogle Scholar
Gunnarsson, I. and Arnórsson, S. (2000) Amorphous silica solubility and the thermodynamic properties of H4SiO4º in the range of 0º to 350ºC at Psat. Geochimica et Cosmochimica Acta, 64, 2295–2307.CrossRefGoogle Scholar
Gunnarsson, I. and Arnórsson, S. (2003) Silica scaling: The main obstacle in efficient use of high-temperature geothermal fluids. International Geothermal Conference, Reykjavik, Iceland, 30–36.Google Scholar
Harrar, J., Locke, F., Otto, C.H. Jr., Lorensen, L., Monaco, S. and Frey, W. (1982) Field tests of organic additives for scale control at the Salton Sea geothermal field. Old SPE Journal, 22, 17–27.Google Scholar
Hawkins, C., Angheluta, L. and Jamtveit, B. (2014) Hydrodynamic shadowing effect during precipitation of dendrites in channel flow. Physical Review E, 89, 022402.CrossRefGoogle ScholarPubMed
Henley, R. (1983) pH and silica scaling control in geothermal field development. Geothermics, 12, 307–321.CrossRefGoogle Scholar
Icopini, G.A., Brantley, S.L. and Heaney, P.J. (2005) Kinetics of silica oligomerization and nanocolloid formation as a function of pH and ionic strength at 25ºC. Geochimica et Cosmochimica Acta, 69, 293–303.CrossRefGoogle Scholar
Kitahara, S. (1960) The polymerization of silicic acid obtained by the hydrothermal treatment of quartz and the solubility of amorphous silica. The Review of Physical Chememistry of Japan, 30, 131–137.Google Scholar
Makrides, A.C., Turner, M. and Slaughter, J. (1980) Condensation of silica from supersaturated silicic acid solutions. Journal of Colloid and Interface Science, 73, 345–367.CrossRefGoogle Scholar
Mountain, B.W., Benning, L.G. and Boerema, J. (2003) Experimental studies on New Zealand hot spring sinters: Rates of growth and textural development. Canadian Journal of Earth Sciences, 40, 1643–1667.CrossRefGoogle Scholar
Mroczek, E., Graham, D. and Bacon, L. (2011) Silica Deposition Experiments: Past Work and Future Research Directions. Proceedings International Workshop on Mineral Scaling in Geothermal Environments, Manila, The Philippines. 51–58.Google Scholar
Stapleton, M. and Weres, O. (2011) Recent Developments in Geothermal Scale Control. Proceedings International Workshop on Mineral Scaling in Geothermal Environments, Manila, The Philippines, 69–76.Google Scholar
Tobler, D.J., Stefansson, A. and Benning, L.G. (2008) In-situ grown silica sinters in Icelandic geothermal areas. Geobiology, 6, 481–502.CrossRefGoogle ScholarPubMed
Tobler, D.J., Shaw, S. and Benning, L.G. (2009) Quantification of initial steps of nucleation and growth of silica nanoparticles: An in-situ SAXS and DLS study. Geochimica et Cosmochimica Acta, 73, 5377–5393.CrossRefGoogle Scholar
Tobler, D.J., Shaw, S. and Benning, L.G. (2013) The insitu and time resolved nucleation and growth of silica nanoparticles under simulated geothermal conditions. Geochimica et Cosmochimica Acta, 144, 156–168.CrossRefGoogle Scholar