Date of Graduation

Spring 2010

Degree

Master of Science in Geospatial Sciences

Department

Geography, Geology and Planning

Committee Chair

Melida Gutierrez

Keywords

carbon sequestration, Lamotte Sandstone, Geochemist's Workbench, solubility trapping, mineral trapping

Subject Categories

Geology | Hydrology | Mineral Physics

Abstract

Increased emissions of anthropogenic CO2 generated by the burning of fossil fuels are contributing to rising CO2 concentrations in Earth's atmosphere. Carbon sequestration is a mitigation technique that will help reduce carbon emissions by capturing CO2 from point sources and storing the CO2 in underground geologic structures. Geochemical modeling is useful in determining the amount of CO2 sequestered through solubility and mineral trapping during and after injection within the target formation. The Southwest Power Station outside of Springfield, Missouri has initiated a carbon sequestration pilot study project targeting the Lamotte Sandstone, the lowermost formation of the St. Francois Aquifer located at 2,000 ft depth beneath the site. Lamotte Sandstone parameters of temperature and fugacity are assumed at 30°;C and 53.3 bar, respectively. Mineralogical analyses of the sandstone show that quartz, feldspars, and smectites are present. Because no public water chemistry data exists for the Lamotte Sandstone in southwest Missouri, water chemistry data reported from four sandstones aquifers were included in the model. Kinetic data of the minerals within the sandstone were also added to the model. The parameters were entered into Geochemist's Workbench (standard 8.0) as a proxy for the Lamotte Sandstone beneath the proposed site and prograde and retrograde phases were simulated. The modeling results of these phases estimate that about 73 g CO2/kg water will be trapped within the formation fluid during the prograde phase and 12 to 25 g/kg water of CO2 will be trapped in the form of carbonate minerals, mainly as dolomite, siderite, and magnesite during the retrograde phase.

Copyright

© Lea Mikensi Nondorf

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