Numerical study on unsteady state dispersion of leakage CO ₂ from geological sequestration

An unsteady state dispersion of CO ₂ leakage from geological sequestration was investigated by using the computational fluid dynamics method for the CO ₂ leakage monitor in the carbon capture and sequestration technology. Three types of wind profiles and some atmosphere and terrain factors affecting the atmospheric gas dispersion were studied. The results show that the dispersion law is consistent under different wind profiles. The vertical variation of wind velocity is greater than that in uniform velocity and logarithm law, and thus the variation of vertical concentration in power law is larger. The stronger instability of atmosphere is more favorable for gas dispersion. Moreover, the influence of atmosphere stability is greater when the measurement location is closer to the leakage source. The time of leakage gas reaching the stable state is shorter with lower stable concentration when the wind speed is faster. The stable concentration increases with an increase in temperature at the same height, which is beneficial for vertical dispersion of the leakage gas. The heavier ground roughness is in favor of forming vertical turbulence and therefore impedes the horizontal dispersion.