Dissolution rate of liquid CO sub(2) in pressurized water flows and the effect of clathrate films

• Main Authors: Hirai, S, Okazaki, K, Tabe, Y, Hijikata, K, Mori, Y
• Format: Conference Proceeding
• Language: English
• ISSN: 0360-5442

The dissolution rate of liquid in CO sub(2) in seawater, when a CO sub(2) clathrate-hydrate film exists at the interface, is a key factor for estimation of CO sub(2) sequestration in ocean and marine environmental impact assessment. Liquid CO sub(2) dissolution phenomena in CO sub(2) sequestration in the ocean include (i) dissolution and diffusion of liquid CO sub(2) droplets at intermediate sea depths and (ii) CO sub(2) dissolution in undercurrent flows from a liquid CO sub(2) pool at seabeds deeper than 3000 m. For the first case, the present paper presents a data base of clathrate-hydrate covered CO sub(2) droplet surface concentration, which is essential for an analysis of CO sub(2) droplet dissolution behavior. Effects of pressure and temperature are included. A numerical simulation for dissolving liquid CO sub(2) droplets released at an intermediate ocean depth is presented. The effects of released droplet size and ambient CO sub(2) concentration on dissolution behavior are clarified. For the second case, an experiment simulating dissolution of liquid CO sub(2) stored at a seabed into an undercurrent flow was conducted. The pool surface was covered with clathrate and the surface concentration of the clathrate-covered CO sub(2) pool was estimated. Applying the measured surface concentration and mass transfer coefficient obtained from the actual conditions of deep ocean data, the time scale of CO sub(2) dissolution into an undercurrent flow was estimated, which is important for estimation of CO sub(2) disposal in the deep ocean.