Numerical Simulation on Mesoscale Diffusion of CO2 Sequestrated in the Deep Ocean in Practical Scenario

Among possible carbon capture and storage (CCS) methods to mitigate the global warming, the direct injection of carbon dioxide (CO₂) into the deep ocean by the moving ship method, is considered to be a feasible way and expected to minimize its environmental impacts on marine organisms in the vicinity of the injection points. In this study, a simple but effective numerical model for the given practical scenario of very large system was developed with adopting moving and nesting grid technique and low- wavenumber forcing technique. The calculated results show that the maximum change of PC02 (DeltaPCO₂) is lower than a given criteria, +5,000 muatm, in the both small- and mesoscale domains. This indicates that the scenario of 30 ships with different length of injection pipes injecting total CO₂ of 50 million t/yr and moving in the 110 times 330 km operation area is efficient and effective. The developed techniques demonstrated its efficiencies and applicability to give an outline for the optimization of the CO₂ ocean sequestration system, by which biological impacts should be minimized and insignificant.