D212 マルチスケールモデルを用いた日本沿岸海底から漏洩したCO_2拡散のシミュレーション(OS12 温暖化対策とCO2削減技術)

Abstract

A numerical simulation was conducted to predict the change in pCO_2 in seawater off a Japanese coast caused by the leakage of CO_2, which is originally stored in a sub-seabed aquifer to sequester CO_2 from the atmosphere. The behaviour of CO_2 bubbles, their dissolution, and the advection-diffusion of dissolved CO_2 were numerically simulated. As a result, it was suggested that the leaked CO_2 bubbles all dissolve in the seawater before spouting up to the atmosphere. The calculated increase of ΔpCO_2 experienced by floating organisms in an extreme case, in which the leakage rate was 94600 t/year, was less than 300 ppm, meanwhile that for immobile organisms right on the fault surface exceeded 500 ppm instantaneously and periodically. In a realistic case, in which the leakage rate was 3800 t/year, ΔpCO_2 and pH experienced by both floating and immobile organisms were in the range of natural fluctuation.