The chemistry and potential reactivity of the CO2-H2S charged injected waters at the basaltic CarbFix2 site, Iceland

• Published in: Energy Procedia
• Main Authors: Clark, Deirdre, Gunnarsson, Ingvi, Aradóttir, Edda S., Arnarson, Magnús Þ., Þorgeirsson, Þorsteinn A., Sigurðardóttir, Sigrún S., Sigfússon, Bergur, Snæbjörnsdóttir, Sandra Ósk, Oelkers, Eric H., Gíslason, Sigurður Reynir
• Other Authors: Jarðvísindastofnun (HÍ), Institute of Earth Sciences (UI), Verkfræði- og náttúruvísindasvið (HÍ), School of Engineering and Natural Sciences (UI), Háskóli Íslands, University of Iceland
• Format: Article in Journal/Newspaper
• Language: English
• Published: Elsevier BV 2018
• Subjects: CO2 sequestration; H2S sequestration; gas injection; mineral storage; CCS; Basalt; Koltvíoxíð; Brennisteinsvetni; Steinefni; Bergfræði; Iceland
• Online Access: https://hdl.handle.net/20.500.11815/1758; https://doi.org/10.1016/j.egypro.2018.07.016

Publisher's version (útgefin grein) The CarbFix2 project aims to capture and store the CO2 and H2S emissions from the Hellisheiði geothermal power plant in Iceland by underground mineral storage. The gas mixture is captured directly by its dissolution into water at elevated pressure. This fluid is then injected, along with effluent geothermal water, into subsurface basalts to mineralize the dissolved acid gases as carbonates and sulfides. Sampled effluent and gas-charged injection waters were analyzed and their mixing geochemically modeled using PHREEQC. Results suggest that carbonates, sulfides, and other secondary minerals would only precipitate after it has substantially reacted with the host basalt. Moreover, the fluid is undersaturated with respect to the most common primary and secondary minerals at the injection well outlet, suggesting that the risk of clogging fluid flow paths near the injection well is limited. This publication has been produced with support from Reykjavik Energy and the European Commission through the projects CarbFix (EC coordinated action 283148) and CO2-REACT (EC Project 317235). Peer Reviewed