Designing Amine-Based\nCapture Units Onboard LNG-Run\nShips

Efficient CO<sub>2</sub> capture onboard ships is a vital\nstep\nin mitigating maritime emissions. In our previous work, we showed\nthat amine-based absorption is the best prospect for onboard capture,\nand ships powered by LNG are better suited than those using HFO. Hence,\nin this work, an extensive design for amine-based absorption onboard\nLNG-run ships with different flue gas conditions (flow rate, temperature,\nand composition) as well as maximum CO<sub>2</sub> storage capacity\nand number of days at sea is presented. The design comprises discussions\non the selection of key variables for separation, e.g., the dimensions\nof the absorber and regenerator column and solvent flow rate, as well\nas the selection of optimal CO<sub>2</sub> storage conditions. Additionally,\nthe best configuration for cold energy integration to minimize the\nextra power demand for the CO<sub>2</sub> compression is also assessed.\nThe design is based on 90% recovery of CO<sub>2</sub> from the total\nflue gas to be processed, including emissions stemming from extra\nfuel burned to fulfill the energy deficit for solvent regeneration\nand the power demand for CO<sub>2</sub> compression. To this end,\na novel noniterative approach to calculate total flue gas to be processed\nas a function of the flue gas conditions under optimized design conditions\nis also developed. Lastly, cargo losses from the installation of the\ncapture unit are also presented. In summary, the study intends to\nprovide ship owners with a comprehensive design guide for the installation\nof an amine-based absorption unit. To illustrate the utility of the\nstudy, case studies are presented using reference ships available\nin the literature.