Study of Solution Process of Carbon Dioxide in Seawater

Abstract

Carbon dioxide (CO₂) ocean sequestration technologies, such as dissolution into seawater, are important to mitigate global warming. In this study, solution processes of CO₂ gas in seawater and pure water were experimentally studied under various pressures and temperatures to evaluate the solubilities of CO₂ in seawater. The solubilities of CO₂ in seawater and pure water were measured by a change in pressure due to absorption at pressures up to 30 MPa and the temperatures ranged from 4°C to 60°C. It was obtained that the solubilities of CO₂ were between 0.27 × 10^-3 and 1.26 × 10^-3 in seawater, and between 0.26 × 10^-3 and 0.6 × 10^-3 in pure water near atmospheric pressure. The values increase with an increase in pressure, but decrease with an increase in temperature. The Henry's law constant of CO₂ was about 105 MPa at a temperature of 4°C in seawater under atmospheric pressure, and increased with an increase in temperature. The solubility of CO₂ in seawater was lower than that in pure water. Empirical correlations for solubilities of C0₂ in seawater and pure water at various temperatures under atmospheric pressure were obtained based on the experimental data.