Conceptualization of CO2 Terminal for Offshore CCS Using System Engineering Process

In this study, the basic configuration and operation concept of a CO2 terminal were identified by conducting a system engineering process. The performance goal of a CO2 terminal was determined by requirement analysis. Then, functions and timelines were derived by functional analysis to meet the performance goal. Equipment to perform the functions were defined and finally, a process flow block diagram of the CO2 terminal was acquired. The CO2 terminal in this study consisted of three parts. First, the CO2 loading/unloading part is responsible for liquid CO2 unloading from the carrier and loading vapor CO2 onto the carrier. Secondly, the liquid CO2 transmission part extracts liquid CO2 from the storage tanks and increases the pressure until it satisfies the offshore pipeline transportation condition. The vapor-treatment part collects boil-off gas, generates vapor CO2, and charges the storage tanks with vapor CO2 to control the pressure of the storage tanks that discharge liquid CO2. Finally, the study results were compared with a liquefied natural gas (LNG) terminal. The biggest difference between the CO2 terminal in this study and the LNG terminal is that a vaporizer is essential in the CO2 terminal due to the smaller storage capacity of the CO2 terminal and, therefore, the lower amount of boil-off gas.