Experimental study on solution and diffusion process of single carbon dioxide bubble in seawater

Abstract

Solution and diffusion process of carbon dioxide (CO 2 ) in seawater is important in the research and development of CO 2 ocean sequestration technology to mitigate global warming. In this study, solution and diffusion process of single CO 2 bubble in seawater and pure water were experimentally studied under various pressures and temperatures to evaluate the transport process of CO 2 in seawater. The solution process was conducted in a test vessel. CO 2 bubble was generated by a CO 2 bubble generator installed at the bottom of the vessel. The diameter of CO 2 bubble was recorded using a high speed video camera. The pressure and temperature of liquids were measured by using a pressure transducer and thermocouples. Experimental conditions for the temperature ranged from 277 K to 297 K, and the pressure ranged from around 101 kPa up to 400 kPa. It was obtained that the complete solution time decreases with the increase in pressure due to its higher solubility at a higher pressure. It decreases with an increase in temperature arising from a higher diffusivity at a high temperature. It was clarified that the complete solution time for CO 2 in seawater is longer than that in pure water due to its relatively lower solubility compared with pure water.

Calculation of the Mass Transfer Coefficient for the Dissolution of Multiple Carbon Dioxide Bubbles in Sea Water under Varying Conditions

“…This result contrasts those from previous studies, which show that the CO 2 diffusion coefficient is greater in distilled water than in sea water. Table 5 shows that the diffusivity and Schmidt number are different based on solvent type [9,17]. As seen in Equation 4, the mass transfer coefficient is affected by diffusivity and Schmidt number; however, the effect of the Schmidt number is greater than that of diffusivity.…”

“…Liu et al [9] experimented on the dissolution and diffusion process of a single CO 2 bubble in sea water and pure water and found that the extinction speed of a bubble is faster if the pressure is higher, the solvent is pure water, and the initial bubble diameter is smaller. Carderbank et al [8] derived the rate of solution, shape, and mass transfer coefficient of CO 2 bubbles in distilled water through experiments.…”

“…Carderbank and Rochiel [8] experimented on mass transfer according to the size of single bubble. Liu et al [9] researched the dissolution and diffusion of carbon dioxide in sea water and distilled water at various temperatures and pressures to store carbon dioxide in the ocean. In terms of carbon capture and storage (CCS) of combustion gas generated from power plants, most previous studies evaluated the carbon dioxide absorption rate using a chemical absorbent or researched the carbon dioxide dissolution characteristics in a single bubble.…”

A holistic approach to the total energy and cost for carbon capture and sequestration

“…where 𝐷 is the diffusion coefficient of CO2 in the seawater, 1.6  10 -9 m 2 /s [54,55]. Therefore, the length scale for the diffusion of the rising CO2 drops is:…”