DENSITY CHANGE OF WATER DUE TO DISSOLUTION OF CARBON-DIOXIDE AND NEAR-FIELD BEHAVIOR OF CO2 FROM A SOURCE ON DEEP-SEA FLOOR

CO2 recovery from the flue gases of fossil energy power sources followed by ocean disposal should be carefully examined in terms of engineering and ecological constraints. For detailed assessment of ocean floor disposal options, the prediction of solute CO2 behavior in the bottom ocean current is important for evaluating the degree of possible damage by the CO2 to the benthic ecosystem. A water coexisting with liquid CO2 in a 35-ml cell (at 3-degrees-C, 343 atm) was sampled and introduced into a vibrating-tube type densitometer. After the density measurement the sample was expanded into a buret system, where the CO2 can be determined volumetrically. Density increase of 0.00284 g/cm3 per 1 wt.% CO2 dissolution was observed, which corresponds to the CO2 partial molar volume of 31.0 cm3/mole. A preliminary computer simulation experiment Of CO2 behavior around "CO2 lake" formed on the deep ocean floor was conducted under the condition as follows: bottom water current; 5 cm/s, thickness of benthic boundary layer; 100 m, vertical eddy diffusivity in the benthic boundary layer; 100 cm2/s. The density flow regime was remarkably observed near the "CO2 lake".