Enhancing the Observation of Above and Below Ground Carbon Sequestration Processes under In Situ Pressure and Temperature Conditions

摘要

Developing a fundamental understanding of the chemical/geochemical reaction mechanisms associated with above-ground mineral sequestration and below-ground geological sequestration is essential to the development of viable processes for carbon mitigation. In situ observations under the pressure, temperature and activities present during sequestration are of particular interest. We have recently developed a microreaction system to observe sequestration reaction processes in situ via synchrotron X-ray diffraction and radiography, Raman spectroscopy, and optical microscopy. The system has been successfully applied to the investigation of above-ground aqueous mineral carbonation processes and is well suited to the investigation of reaction processes of interest to below ground sequestration as well. To complement the capabilities of the microreaction system, we have developed a novel high pressure NMR (HP-NMR) probe to further explore above and below ground sequestration processes under in situ temperature, pressure, and activity conditions of interest. Combined, these systems can provide insight into a variety of sequestration phenomena, including fluid-solid and fluid-fluid reaction mechanisms and interactions, fluid speciation, dissolution, and diffusion, and sequestration product phase stability and behavior. Initial observations of above ground aqueous mineral sequestration reactions have revealed (ⅰ) the relative carbonation reactivity of activated feedstock minerals, (ⅱ) the relative reactivity of fluid reaction species, and (ⅲ) the ability to identify carbonate phase formation and stability as a function of temperature, pressure, and aqueous solution activity, which is also of inherent interest for below ground sequestration. Extending these capabilities to explore the geochemistry associated with below ground sequestration is discussed, along with our initial observations of fluid speciation and transport of interest to above and below ground sequestration.