Design of carrier-based offshore CCS system: Plant location and fleet assignment

摘要

As part of efforts to mitigate the global effects of greenhouse gases from fossil fuels, CO_2 Capture and Storage (CCS) technology has drawn large attention from the engineering research community. Compared to a pipeline-based system, an offshore CCSsystem using Liquefied CO_2 (LCO_2) carrier ships and offshore oil wells is expected to offer a more flexible and efficient mode of CCS to many countries, especially nations such as Korea where a pipeline-based system is inherently infeasible. In this paper we discuss a carrier-based offshore CCS system, in which CO_2 carriers may transport crude oils on inbound voyage, and seek the optimal configuration of the system including liquefaction plant location, fleet assignment, and the optimal pressure andtemperature of the cargo CO_2. We determine the optimal system configuration including the liquefaction plant location and CO_2 carrier fleet assignment with respect to the overall transport cost of the CCS system. We use two sequential linear programming problems - plant location and fleet assignment, with the pressure and temperature state of cargo CO_2 as the key CCS chain parameters. We find that the optimal state of CO_2 at each stage in the system can deviate from the triple point, depending on the system's configuration and throughput. As a case study, we demonstrate that the optimal cargo state can be different from the triple point depending on the system configuration. In this case it is -39 °C and 10 bar and the overall transport cost of CO_2 sequestration is 26.7 USD/ton. This result is based on the specific scenario of the CO_2 Capture and Storage system for Korea using southeastern Asian offshore oil wells.