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

在各种CO_2海洋封存技术中，限制大气CO_2浓度升高的措施是通过船舶拖曳管释放CO_2液滴，通过船舶运动稀释溶解的CO_2来减少生物影响。在1500 m左右释放的CO_2液滴，由于浮力作用而上升，在500- 1500 m深度溶解的CO_2被认为在20-100年内释放到大气中。本文提出了一种新的海洋CO_2封存概念，即CO_2在比释放点更深的海水深度溶解（即，1500米），生物影响最小。在运动船舶的拖曳管尖端释放CO_2液滴之前，通过向CO_2液滴内部注入水小液滴形成水合物线颗粒。由于水合物的密度为1.1g/cm ~ 3，含40vol%以上的水合物线颗粒的CO_2液滴从释放点向下沉降到深海中，导致较长时间的封存。此外，由于海洋平均水深4000 m，CO_2液滴溶解的远距离传播使CO_2溶解稀释，大部分海域的pH值剖面大于7.0，生物影响最小。通过实验验证了这一概念。

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.