이산화탄소 해양지중저장 최신연구동향

Abstract

Carbon dioxide Capture and Storage (CCS) is regarded as one of the most promising options to response severe climate change. CCS is to capture CO2 from major point sources such as power plants and ironworks, to transport to the storage sites and to store CO2 into the subsurface geological structure. Especially, offshore geological storage has been recognized as a more feasible method due to its reliability and practicality. Since 2005, we have developed relevant technologies and focused on the marine geological storage of CO2. Those technologies include possible storage site surveys and basic designs for CO2 transport and storage processes. To design a reliable CO2 marine geological storage system, we devised a hypothetical scenario and used a numerical simulation tool to study its detailed processes. Before going to main calculation of process design, we compared and analyzed the relevant equation of states. Up to now, process design for this CO2 marine geological storage has been carried out mainly on pure CO2. Unfortunately the captured CO2 mixture contains many impurities such as N2, O2, Ar, H2O, SOx, H2S. A small amount of impurities can change the thermodynamic properties and then significantly affect the compression, purification and transport processes. Among them, non-condensable gases can make unexpected two-phase flow during the transport and injection process resulted in severe pressure drop, pulsation, etc. To predict the CO2-N2 mixture behavior, optimum binary parameter to consider the interaction of CO2 and N2 molecules was suggested based on the mean absolute percent error. And the existence of water in the CO2 stream can make a hydrate during the high pressure and low temperature condition process. It is one of the most important design requirements to avoid the hydrate formation and predict hydrate behavior. The phase equilibrium of CO2 gas mixtures, including water, hydrate and electrolyte, has been investigated. Two and three-phase equilibria wer