Development of stable geological storage technology by using CO2 micro droplets

CO2地质封存是大幅度减少CO2向大气排放的最可行方法之一。在含水层中的温度和压力条件下，CO2成为超临界状态，CO2在浮力的作用下向上运移。为了降低渗漏风险，在这项研究中，建议注入纳米尺度的CO2液滴到含水层。利用表面活性剂制备了超临界CO2纳米液滴，并对其粒径和分布随时间的变化规律进行了实验研究。在高CO2密度和低温条件下，观察到稳定的超临界CO2液滴。利用X射线CT对注入多孔介质的超临界CO2液滴进行了观察。然而，CO2液滴在孔隙尺度上生长，通过毛细管力被稳定地捕获在每个孔隙中。

CO2 geological sequestration is one of the most feasible methods for substantial reduction of CO2 emissions into the atmosphere. Under conditions of temperature and pressure in aquifer, CO2 becomes supercritical state and upward migration of CO2 is caused by the buoyancy force. In order to reduce the leakage risk, injecting nano-scale CO2 droplets into the aquifer is proposed in this study. Nano-scale supercritical CO2 droplets were generated with surfactant and investigated their time evolution of its diameter and the distribution experimentally. At high CO2 density and low temperature condition, stable supercritical CO2 droplets were observed. Supercritical CO2 droplets that were injected into the porous media were observed by using X-ray CT. The CO2 droplets grew at pore-scale, however, were stably trapped in each pore by capillary force.