The Performance of Low-Pressure Seawater as a CO₂ Solvent in Underwater Air-Independent Propulsion Systems

• Main Authors: Eun-Young Park, Jungho Choi
• Format: Article
• Language: English
• Published: MDPI AG 2020-01-01
• Series: Journal of Marine Science and Engineering
• Subjects: carbon dioxide; co₂ dissolution; underwater weapon systems; diffusion; diffusion coefficient
• Online Access: https://www.mdpi.com/2077-1312/8/1/22

Air-independent propulsion systems have improved the performance and decreased the vulnerability of underwater weapon systems. Reforming systems, however, generates large amounts of water and CO₂. The recovery or separation of CO₂, a residual gas component generated in vessels, entails considerable cost and energy consumption. It is necessary to understand the characteristics of the interaction between CO₂ and seawater under the conditions experienced by underwater weapon systems to design and optimize a CO₂ treatment process for dissolving CO₂ in seawater. In this study, numerical analysis was conducted using the derived experimental concentration and MATLAB. The diffusion coefficient was derived as a function of temperature according to the CO₂ dissolution time. Experiments on CO₂ dissolution in seawater were conducted. The concentration of CO₂ according to the reaction pressure and experimental temperature was obtained. The diffusion coefficient between CO₂ and seawater was found to be 6.3 × 10^−5 cm²/s at 25 °C and 7.24 × 10^−5 cm²/s at 32 °C. CO₂ concentration could be estimated accurately under vessel operating conditions using the derived CO₂ diffusion coefficients. Optimal design of the residual gas treatment process will be possible using the derived seawater−CO₂ diffusion coefficients under the actual operating conditions experienced by underwater weapon systems.