Carbon capture and sequestration (CCS) is part of the global challenge of mitigating global warming and climate change. Geological sequestration of carbon dioxide (CO 2 ) is an immediately available and technologically feasible method for achieving a substantial reduction in carbon dioxide emissions into the atmosphere. Because the density of CO 2 is lower than that of water, injected CO 2 migrates upward in an aquifer owing to the buoyancy force. Therefore, a highly impermeable layer is generally employed to prevent CO 2 leakage from the storage reservoirs. For these reasons, assessment of the storage site, leakage risks, and storage costs are one of the main issues in CO 2 geological sequestration. The intent of the present study was to clarify the fundamental mechanism of CO 2 migration in a reservoir.The behaviour of liquid CO 2 in water-saturated silica packed bed was observed using high spatial resolution X-ray computed tomography. As the result, CO 2 behavior in the water saturated porous structure was visualized with 20 μm resolution, and it was found that the permeation and distribution of liquid CO 2 were strongly dominated by the local pore size and its structure.

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In this study, we developed a visualization system of gas flow behavior called laser ablation tagging visualization (LATV), which showed a strong potential to examine flow behaviors in gas flow channel in an operating proton exchange membrane fuel cells (PEMFC). We constructed LATV system with two pulsed lasers: one is for laser ablation tagging and the other is for excitation of the tag material for visualization. The system was validated and was also applied to an operating PEMFC. Flow velocity in gas channel at operating conditions was examined with variation of current density. Under low current density condition, gas flow velocity was well consistent with theoretical values calculated from supplied volume flow rate at the inlet. On the other hand, result under high current density condition shows that flow velocity in the cathode channel accelerated toward the downstream, possibly due to generation of water vapor and enhancement of water transport across the MEA from the anode to the cathode.