Process design for a new injection method of liquid CO2 using a static mixer was conducted based on laboratory experimental results on the formation process of liquid CO2 drops covered with hydrate film by a Kenics-type static mixer, and numerical simulation of the liquid CO2 drops at 500 and 1500 m. The Sauter Mean Diameter (SMD) of the liquid CO2 drops covered with hydrate film was dramatically decreased with the use of the static mixer; empirical equations were obtained for the SMD, and also the maximum and minimum diameters of the liquid CO2 drops for a given flow velocity (Weber number, We). The ascending and dissolving behavior of a liquid CO2 drop with hydrate released in the ocean at an intermediate depth was numerically simulated, and the maximum drop diameter to avoid evaporation of the drop before complete dissolution was estimated. Based on these results, scaling up of the static mixer was conducted by assuming a disposal process Of CO2 emitted from a 100-MW thermal power plant, and the mixer diameter was determined as a function of the given SMD. Moreover, the power consumption of the static mixer was evaluated and found to be almost negligible. (c) 2005 Elsevier B.V. All rights reserved.