Carbon Capture and Storage

CO₂ capture and mineralization by seawater - mafic rock mixture:

The urgent need for large scale carbon dioxide removal (CDR) to limit global warming is increasingly evident. It is estimated that between 100 and 1000 Gt (Gigatonne) of CO₂ will have to be removed from the atmosphere by the end of the 21st century to limit global warming to 1.5^oC compared to preindustrial levels. Carbon capture and storage (CCS) technologies are an intriguing CDR method as CO₂ can be captured from exhaust streams or directly from the atmosphere. As of 2020, only 40 Mt (Megatonne) CO₂ is captured from concentrated sources and stored in geological formations per year, while global annual CO₂ emissions amounted to 42 Gt CO₂ in 2019. The imbalance between current CCS and anthropogenic CO₂ release highlights the need for research and development of efficient CCS Techniques.

Carbon dioxide storage through its mineralization in the subsurface is a low risk technique as carbon bound in stable carbonate minerals has minimal leakage risk. One method is the mineralization of freshwater-dissolved CO₂ injected into mafic rock. While this injection method drastically reduces the risk of CO₂ leakage to the surface (the injection fluid is not a buoyant fluid), substantial amounts of water are required. At 30 bar pressure and 20C, around 22 metric tons of freshwater are needed to dissolve one ton of CO₂. Therefore, the large-scale application of this method requires large amounts of fresh water and faces potential usage conflicts.

The use of seawater as a solute is a potential alternative to fresh water. Vast quantities of seawater are available in the immediate vicinity of the oceanic mafic rock, a reservoir with a storage potential of ~3x10⁵ Gt CO₂.

In this project we will explore the feasibility of carbon capture and storage by seawater - mafic rock mixture, both as a bench top model and as a scaled up system. We will quantify the solubility of carbon dioxide in seawater as a function of pressure and temperature and will look into different mafic rock formations to find the best one for carbon capture. We will then model the scaled up system for industrial applications.

Kinetic Analysis of Carbon Capture Adsorbents:

The increase in carbon emission changes the amount of greenhouse gases trapped in the Earth’s atmosphere. The imbalance of the greenhouse gas causes the Earth’s equilibrium radiative force to change. Carbon dioxide (CO₂) accounts as the primary greenhouse gas emitted by humans. The changes of the CO₂ concentration in the atmosphere contributes to the changes of radiative force consequently giving rise to greenhouse effects. Direct-Air-Capture (DAC), a technology to capture CO₂ directly from the atmosphere for utilization or sequestration purposes is a mitigation approach to greenhouse gas emission.

The objective for this project is to obtain kinetic parameters for adsorbents used in DAC technologies. The kinetic parameters will be obtained using Thermogravimetric Analysis (TGA) and Differential Scanning Calorimetry (DSC). Off-the-shelf materials will be used as well as applications of BECCS, Bioenergy with Carbon Capture and Storage. Storage will be ignored for now, but the generation of activated carbons can be investigated via thermal treatment (torrefaction, pyrolysis, gasification, and/or combustion).

Develop Theoretical Model of Carbon Capture Adsorbents:

Model or correlate the kinetic parameters versus CO₂ performance for adsorbent material.
Use Machine Learning Techniques to fit models to the vast amount of data existing for carbon capture.