Techno-economic assessment of CO₂ liquefaction for ship transportation

Carbon capture and storage (CCS) is a key technology for addressing global warming by capturing carbon dioxide and storing it somewhere, usually underground. The transportation of CO₂ is required since storage sites are not necessarily present near the source sites. Ships can be used for long distance transport of CO₂. However, CO₂ sources are not always located near the coast; hence onshore transportation may be required in addition to ship for transportation of CO₂ from source sites to storage site. Liquefaction is a vital component in ship transportation. In this study, a state-of-the-art CO₂ liquefaction processes have been designed by taking CO₂ capture facilities into account. The proposed processes require lower liquefaction energy compared to other processes found in the literature. Suitable thermodynamic conditions are required for economical transport of CO₂. Therefore, three scenarios each for post-combustion and pre-combustion have been studied in order to explore the effect of thermodynamic conditions on the economics of CO₂ transport. The considered scenarios are categorized on the basis of liquefaction plant location as: (i) the capture site, liquefaction plant and shipping terminal are located close to each other; (ii) the capture site and liquefaction plant are far from shipping terminal; (iii) the capture site is far from liquefaction plant and shipping terminal. The scenarios results were useful for deciding the optimum liquefaction plant location. Finally, an economic analysis is performed in order to evaluate the feasibility of CO₂ transport from source sites to ship loading terminal.