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| Titel |
Mineral sequestration of carbon dioxide in peridotitic and basaltic rocks using seawater for carbonation |
| VerfasserIn |
Domenik Wolff-Boenisch, Stefan Wenau, Sigurdur Gislason |
| Konferenz |
EGU General Assembly 2010
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 12 (2010) |
| Datensatznummer |
250041602
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| Zusammenfassung |
| In-situ mineral sequestration requires huge volumes of water for carbonation of CO2 which is
injected as one fluid phase into the appropriate reactive subsurface for subsequent
mineralization. The amount of water needed to dissolve one ton of CO2 is about 27 tons at 25
bar partial pressure and 25 Ë C (Gislason et al., 2010). The CarbFix pilot injection
project at the Hellisheidi geothermal power plant in SW Iceland taps a shallow
aquifer to overcome this critical issue of water demand. Fresh water sources in
Iceland are plenty and often replenished. However, areas of basaltic rock suitable
for CO2 mineral sequestration are often situated in more arid climate zones or in
areas of high population density with high drinking water demand, e.g. the Indian
Deccan Trapps. To overcome this problem, CO2 can alternatively be dissolved
in seawater prior to injection, as the amount of available seawater is practically
unlimited. Furthermore, the ocean floor has been discussed as potential CO2 storage site
(Goldberg et al., 2008) conferring seawater a key role in the viability of this trapping
technique of carbon dioxide, irrespective of additional technical challenges and
costs.
Based on its much higher amount of total dissolved solids seawater displays
some different properties from fresh water that may be harnessed to increase the
efficiency of fluid-rock interaction and the precipitation of carbonates. Especially
some of the seawater anions, e.g., fluoride, sulfate, and organic compounds have
been shown to accelerate the dissolution kinetics of basaltic glass (Oelkers and
Gislason, 2001; Wolff-Boenisch et al., 2004; Flaathen et al., 2009) and may also
potentially enhance dissolution reactions of peridotite or crystalline basalt. Such
increased dissolution kinetics would cause a faster rise in pH due to enhanced proton
consumption in the dissolution reaction and also increase the amount of solute
divalent cations, both crucial processes to successful carbonatization, a pH sensitive
process.
The aim of this contribution is to bridge the gap of available studies for basaltic glasses
and the lack of kinetics data for crystalline basalt and peridotite dissolution in seawater and in
the presence of CO2(aq) in order to gain insight into the effects of seawater and its
components on the kinetic processes and geochemical interactions that will lead to solid CO2
sequestration. Results from dissolution experiments in mixed-flow reactors under constant
pCO2 and as a function of seawater solution chemistry with crystalline and glassy basalt and
peridotite will be presented and the implications for enhanced in-situ as well as ex-situ CO2
mineralization discussed.
References
Flaathen, T.K., Oelkers, E.H., and Gislason, S.R. 2008. Min. Mag. 72: 39–41.
Gislason, S.R., Wolff-Boenisch, D., Stefansson, A., Oelkers, E.H., Gunnlaugsson, E.,
Sigurdardottir, H., Sigfusson, B., Broecker, W.S., Matter, J.M., Stute, M., Axelsson, G., and
Fridriksson, Th. 2010. Int. J. Greenhouse Gas Control, in print.
Goldberg, D.S., Takahashi, T., and Slagle, A. 2008. PNAS 105: 9920–9925.
Oelkers, E.H. & Gislason, S.R. 2001. Geochim. Cosmochim. Acta 65, 3671–3681.
Wolff-Boenisch, D., Gislason, S.R., and Oelkers, E.H. 2004. Geochim. Cosmochim. Acta
68: 4571–4582. |
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