InterPore2023

Carbon sequestration in porous materials: Uniform CO2 flooding and reaction front

24 May 2023, 16:10

1h 30m

Poster Presentation (MS06-A) Physics of multiphase flow in diverse porous media Poster

Speaker

Dr Roi Roded (Civil and Environmental Engineering, Duke University, Durham, NC, USA)

Description

Injection of a $\rm{CO_2}$-rich phase into a porous material initially saturated with water solution (i.e., drainage) leads to $\rm{CO_2}$ dissolution and mass-transfer into the resident water solution. As a result of the accompanying decrease in solution pH, the solid matrix can be in chemical disequilibrium and induce dissolution-precipitation reactions such as carbonation (i.e., carbonate mineral formation) on the wetted surfaces. In turn, the chemical disequilibrium leads to continued undersaturation and dissolution of $\rm{CO_2}$ and a substantial net mass-flux from the $\rm{CO_2}$-rich phase to the solution phase. Such immiscible drainage with mass-transfer is a scenario shared with major capture and/or sequestration systems, ranging from a carbonation in cement-based-materials [1] and in natural aquifers composed of ultramafic rocks (e.g., basalts) [2] to selective capture and separation in industrial porous materials [3] and to caprock integrity estimations in subsurface $\rm{CO_2}$ storage [4].
Under certain conditions, viscous fingering instabilities can emerge from the initially planar front and develop to preferential flow pathways for the $\rm{CO_2}$-rich phase. These flow pathways can then lead to a bypass of the bulk medium and eventually failure in substantial capture or sequestration of $\rm{CO_2}$ methods [5]. In this study, using in situ $\rm{CO_2}$ flooding experiments in a Portland cement-based mortar acquired using X-ray micro-computed tomography [6] and theoretical analysis of linear stability, we characterize the conditions for the emergence of viscous fingering. We find non-trivial effects of the mass-transfer term, which strongly depends on the degree of saturation. The results contribute to improving Carbon Capture and Storage (CCS) techniques in both natural and engineered porous materials and to the advancement of carbon-negative materials, which are crucial for mitigating climate change.

References

[1] Liu, B. et al., Constr. Build. Mater. 272, 121660, 2021.
[2] Kelemen, P. B. et al., Chem. Geol. 550, 119628, 2020.
[3] Babu, P. et al.,. Energy, 85, 261-279, 2015.
[4] Tian, H. et al., Acta Geotech. 9(1), 87-100, 2014.
[5] Berg, S. & Ott, H., Int. J. Greenh. Gas Control 11, 188–203, 2012.
[6] Dalton, L. E., Crandall, D., & Pour-Ghaz, M., Int. J. Greenh. Gas Control 116, 103632, 2022.