Ole Ivar Ulven will defend his PhD thesis

Thesis title: Carbonation of ultramafic rock: Mechanochemical aspects

Results from numerical models of reaction-induced fracturing

The presence of vast amounts of carbonate minerals in the lithosphere has suggested mineral carbonation as an option for safe, permanent sequestration of CO2. Ultramafic rocks react naturally with CO2 to form carbonates, and are available in significant amounts. Although the reaction rate is usually too low to be of interest for large scale CO2 sequestration, several options have been suggested for accelerating the carbonate formation. As carbonates form, the rock will expand. This might lead to fractures, which can serve as transport channels for CO2, and give access to fresh, unreacted rock. In this thesis, it is studied whether fracture formation can provide a positive feedback in a carbonation process. A discrete element model is developed, and applied to a reaction-diffusion process that describes a volume increasing reaction. Furthermore, natural carbonate formation is studied in the field. The presented data shows that fractures can accelerate the carbonation process significantly, and that if the formed fractures remain open and CO2 is injected fast enough, carbonates may be formed at high enough rate to make it a viable option for industrial scale CO2 sequestration.

Full information on Trial lecture and defence: http://www.mn.uio.no/fysikk/forskning/aktuelt/arrangementer/disputaser/2014/Ulven.html

Published Oct. 31, 2014 1:38 PM