Dissolution of CO2 Drops and pH Change in CO2 Ocean Storage

Abstract

The dissolution rate of CO2 drops with CO2 hydrate films was investigated to estimate the environmental impacts of the ocean storage of CO2. The diameter of dissolving CO2 drops was measured and compared with that from a theoretical model, where the mass transfer coefficient is provided by Ranz-Marshall's equation to involve the effect of water flow on the dissolution rate. The pH in ambient water around the drops was also measured to obtain the CO2 concentration in ambient water, which is also incorporated into the model. The dissolution rate of the CO2 drop was obtained from both the model and the experimental results. The experimental dissolution rate was enhanced by an increase in flow velocity similar to the predicted rate; however, the experimental dissolution rate was lower than that predicted. Moreover, the difference between the experimental and predicted dissolution rates became higher due to an increase in flow velocity.