One way to reduce greenhouse emissions while minimising disruption to high-carbon industries is to capture the emitted carbon dioxide before it enters the atmosphere, then store it deep underground at high pressure, inside porous rocks.
The successful storage of the carbon dioxide (CO2) is based on a combination of potential trapping mechanisms. CO2 can be stored if it is captured locally in brine filled sub-millimeter pores, can be trapped permanently under a thick, impermeable seal, can be converted into solid minerals or adsorbed on mineral surfaces. Confidence for future investment in carbon storage requires successful prediction of the movement and trapping capacity of CO2 within potential storage reservoirs. The Department of Applied Mathematics, Research School of Physics and Engineering, at ANU is contributing to this improved prediction of CO2 storage potential by addressing the impact of geological heterogeneity on the movement of CO2 through the subsurface at multiple length scales. The study focusses on rock material from a Carbon capture and storage (CCS) demonstration project based in the Surat basin, Queensland.
The Department isusing its custom X-ray microtomographic facility, along with specially designed high pressure flow apparatus to directly visualise the CO2-water interaction inside rocks. This provides a unique tool that will provide a better understanding of what is happening when we try to sequester carbon dioxide deep underground. The work, supported by the Australian National Low Emissions Coal Research & Development (ANLEC R&D), enabled researchers to successfully visualize the core-flow studies of super-critical CO2 (scCO2) and brine in Surat basin core at elevated pressure and temperature. A second outcome of the program was the development of a new pore scale model for brine:CO2 injection that provides estimates of the ability of an aquifer to trap CO2 within individual pores—the most important storage mechanism for the successful long term storage of CO2 in the Surat basin. The models required no fitting parameters and offered excellent agreement between experiment and simulation.
In further work with ANLEC R&D, ANU researchers are investigating the role of geological heterogeneity at multiple length scales by coupling laboratory-based (cm scale) results with models of the Surat basin geological features based on outcrop studies (10m scale).
In the next 50 years, the world's fuels must be decarbonised. Endex thermoreactive principles underpin new high efficiency systems for separating carbon from fuels and flue gases. In collaboration with Imperial College London, the University of Leeds, CanMet Energy, and an industry partner, researchers in this group are developing a suite of Endex carbon capture technologies.
Dr Rowena Ball is leading a major collaborative project with the Global CCS Institute that aims to design and build a universial toolkit for effectively comparing the efficiency and capture penalty of different carbon capture systems using exergy analysis. The CCS research group has received major infrastructure funding and made some important findings in work. For instance, in association with the Cooperative Research Centre for Greenhouse Gas Technologies (CO2CRC), the ANU was granted $5.1m in infrastructure funding from the Department of Education’s Education Investment Fund (EIF) that supports clean energy research infrastructure. This funding is being used to construct a lab that will provide imaging and core-flooding capabilities that are critical for determining the viability of carbon storage within aquifers at the CCS flagship sites.