Efficient onboard carbon capture system using methanol-fueled solid oxide fuel cells

Green methanol is considered an important future hydrogen carrier in the maritime sector, however, its wide scale use is expected to be limited by the scarcity of biogenic carbon. This paper proposes a concept where onboard carbon capture (OCC) is used to facilitate a cyclic use of biogenic carbon by storing the captured CO₂ which can be re-used to produce new green methanol. To enable this concept a novel methanol-fueled solid oxide fuel cell system with cryogenic CO₂ capture partly using absorption cooling is proposed. Three configurations of this system are developed. Based on steady-state thermodynamic models, it was found that the best system configuration was able to reach a steam-to-carbon ratio of 2, a system fuel utilization of 100%, zero emissions, and a lower heating value electrical system efficiency of 63.9%. This is on a par with the best power generation and OCC systems currently proposed in the literature.