ABSTRACT The purpose of the present study is to reveal the influence of CO2 hydrate on the flow of liquid CO2 injected in a packed column as simulating seabed. In order to reveal the influence of CO2 hydrate, differential pressure and temperature are measured under both conditions of CO2 hydrate formation and no-formation. As the result, the amount of CO2 hydrate estimated from temperature suggested decreasing as the flow rate increases. The difference of friction factor between both conditions becomes small with increase of Reynolds number in the upstream part of packed column.
INTRODUCTION In the method of CCS (carbon dioxide capture and storage), storage of CO2 under the seabed such as aquifers has been expected as one of the effective options for the mitigation of global warming. Under the condition of pressure higher than 4.5 MPa and temperature lower than 283.4 K, CO2 clathrate hydrate is formed. CO2 hydrate prevents liquid CO2 from dissolving into water. In the sea around Japan, there is the region with sufficient environment for CO2 hydrate formation. Therefore, liquid CO2 injected in seabed sediments in those regions reacts with pore water and forms CO2 hydrate. The hydrate-filled sediments (hydrate sealing) are expected to serve as an article cap rock, and prevent the escape of CO2. Thus, the method of CO2 storage under the seabed is of little influence on the marine environment and long term storage is possible. However, when liquid CO2 is injected into seabed in those regions, there is at risk of choking liquid CO2 flow due to CO2 hydrate formation in a pipe arrangement and seabed. Therefore, it is important to clarify the influence of the hydrate on CO2 storage under the seabed. The previous studies of the hydrate formation in a packed column were mainly performed under the condition that the flow rate of CO2 is low such as to allow the generation of seal layer by the hydrate formation.