Advance CO_2 Ocean Disposal for Long-term Sequestration and Reduced Biological Impact

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Among various CO_2 ocean sequestration technologies, measures to restrict the increase of atmospheric CO_2 concentration, releasing CO_2 droplets from towed pipe of ship reduces biological impact by the dilution of dissolved CO_2 due to the motion of moving ship. CO_2 droplets, released around 1500m ocean depth, rise upward due to buoyancy and dissolved CO_2 at the sea depth of 500-1500m is considered to outgas to the atmosphere in 20-100 years. Here, we present a new concept of CO_2 sequestration in the ocean that CO_2 would dissolve at the sea depth deeper than the release point (I.e., 1500m) and biological impact would be minimized. Before releasing CO_2 droplets from the tip of towed pipe of moving ship, hydrate line particles are formed by injecting water small droplets inside CO_2 droplets. Since density of hydrate is 1.1g/cm3, CO_2 droplets including hydrate line particles more than 40vol% sink downward from release point into deep ocean that result in longer term sequestration. In addition, since depth of ocean is 4000m on an average, long travel distance for CO_2 droplets dissolution enables diluted CO_2 dissolution、 pH profiles in most of the part of sea depth would be larger than 7.0, Where biological impact would be minimized. The present concept is verified by an experiment.