Carbon capture and storage (CCS) in deep saline aquifers has been considered as one possible means of reducing greenhouse gas emissions. However, there are latent risks for which carbon dioxide (CO2) could migrate from the deep saline formations to shallower aquifers. CO2 leaks could reach an underground source of drinking water (USDW) and dissolve in the water, thereby increasing the acidity of the USDW, which could enhance the solubility of hazardous compounds. In this paper, we explored the possibility of detecting such leakage by the use of laser-induced breakdown spectroscopy (LIBS). LIBS experiments were performed using a 5-ns pulsed Nd:YAG laser operating at 1064-nm. A Stainless steel high-pressure vessel was used for forming plasma in bulk aqueous solution of calcium chloride. The experiments were conducted at different pressure (10, 50 and 120 bar). Two gases with large water solubility contrast (CO2 and N2) were examined as to their influence on the intensity of Ca lines at 422.67 and 393.37 nm. Results show that Ca lines intensity decreases more rapidly with increasing N2 pressure than with increasing CO2 pressure. Regardless of whether CO2 or N2 is used, we observed an increase in the electron density at 120 bar, in late-stage plasma evolution. This may indicate that pressure has a similar or predominant influence on plasma electron density than change in solution chemical compositions. Improvement of the LIBS measurement in high-pressure CO2 environment may be possible through optimization of LIBS signal.

Application of laser induced breakdown spectroscopy (LIBS) to analyze CO2-bearing solutions in HTHP environment

248th National Meeting (2014)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.