In this study, a techno–economic model was used to calculate the costs of CO₂ transport and specify the major equipment required for transport in order to demonstrate and implement CO₂ sequestration in the offshore sediments of South Korea. First, three different carbon capture and storage demonstration scenarios were set up involving the use of three CO₂ capture plants and one offshore storage site. Each transport scenario considered both the pipeline transport and ship transport options. The temperature and pressure conditions of CO₂ in each transport stage were determined from engineering and economic viewpoints, and the corresponding specifications and equipment costs were calculated. The transport costs for a 1 MtCO₂/year transport rate were estimated to be US$33/tCO₂ and US$28/tCO₂ for a pipeline transport of ~530 km and ship transport of ~724 km, respectively. Through the economies of scale effect, the pipeline and ship transport costs for a transport rate of 3 MtCO₂/year were reduced to approximately US$21/tCO₂ and US$23/tCO₂, respectively. A CO₂ hub terminal did not significantly reduce the cost because of the short distance from the hub to the storage site and the small number of captured sources.

This study describes the numerical modeling of coupled turbulent fluid flow, heat, and solute transport in a continuous slab caster with an electromagnetic brake (EMBr). Transport equations of total mass, momentum, energy, and species for a binary iron–carbon alloy system are solved using a continuum model. The turbulent effects are taken into account using the standard k–ϵ equations, where coefficients are appropriately modified for phase change. The electromagnetic field is described by Maxwell equations. A finite-volume method is employed to solve the conservation equations associated with appropriate boundary conditions. The process variables considered are the casting speed, magnetic flux density, and carbon segregation. The effects of these process variables on the velocity, temperature, and solute distributions are reported and discussed.

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.

Autonomous underwater vehicles have long been used in marine explorations, and their application in recent polar expeditions is particularly noteworthy. However, the complexity and extreme conditions of the polar environment pose risks to the stable operation of autonomous underwater vehicles. This study adopted the methodology of fuzzy fault tree analysis to deeply analyze the operational risks of autonomous underwater vehicles in polar environments. While traditional fault tree analysis maps the causal relationships and probabilities between basic and intermediate events, fuzzy fault tree analysis models the uncertainty of data and determines the failure probability by integrating expert opinions. This study revealed that polar environment-induced failures play a more substantial role in autonomous underwater vehicle loss in polar regions than inherent system failures. The study identified ‘recovery failure’ and ‘poor communication’ as the major risk factors facing autonomous underwater vehicles in polar environments, exhibiting the highest failure probabilities. Specifically, among various polar environmental factors, ‘large ice concentration’, ‘ice thickness’, and ‘roughness of ice underside’ under ‘bad’ conditions were found to have a significant impact on the autonomous underwater vehicle’s failure probability. The fuzzy fault tree analysis method in this study successfully filled the gap created by the absence of historical data by effectively incorporating expert opinions, enabling a quantitative presentation of the impact of polar environments, which has been previously difficult to convey in qualitative terms.

This study investigates the transient behavior of an electro-thermal drilling probe (ETDP) during a close-contact melting process within a glacier. In particular, the present work analyzes the effect of the tip temperature on the formation of molten thin liquid films and the subsequent rate of penetration (ROP) through numerical simulation. We used the commercial code of ANSYS Fluent (v.17.2) to solve the Reynolds-averaged Navier–Stokes equation, together with an energy equation considering the solidification and melting model. The ROP of the drilling probe is determined based on the energy balance between the heating power and melting rate of ice. As the results, the ETDP penetrates the ice through a close-contact melting process. The molten liquid layer with less than 1 mm of thickness forms near the heated probe tip. In addition, the ROP increases with the heated temperature of the probe tip.