Researchers from Austria and Sweden have modelled the potential for pre- and post-combustion carbon capture for a ferry burning renewable methanol and hydrogen and concluded that both systems would be cost effective.
The propulsion demand of a 240-metre, 51,837gt ferry operating in the Baltic Sea was used in the analysis to simulate a typical ro-pax in the region.
Four configurations were compared:
Case A: conventional engines burning marine gas oil.
Case B: hybrid propulsion with dual-fuel engines burning renewable methanol connected to an onboard electric system via gearboxes and electric machines, with a battery storage system.
Case C: Renewable methanol with pre-combustion carbon capture that reforms the methanol to hydrogen using heat from the engine exhaust gas. The engines run flexibly on either hydrogen or methanol and theCOâ‚‚ remaining after the reformation is separated in a membrane reformer, liquefied, and stored on board.
Case D: Renewable methanol with carbon captured from the exhaust gas using an amine-based solvent which uses heat from the exhaust gases for solvent regeneration. The COâ‚‚ is liquefied and stored on board.
The researchers achieved cost-effective designs in both cases C and D (pre-combustion and post-combustion carbon capture technology) which resulted in a 20% cost advantage compared to the systems without carbon capture. Exhaust gas heat was sufficient to capture about 90% of theCOâ‚‚ in the post-combustion carbon capture system and about 37% in the pre-combustion system. The lower rate was due to the higher temperature demanded by the methanol reformer. The addition of burners could increase that rate.
The researchers note that the costs of removingCOâ‚‚ in port would need to be factored into a full economic assessment, as would space requirements for the system and hotel demands of the vessel.
The study was published in Energy Conversion and Management by researchers from the Large Engines Competence Center, Graz University of Technology, Austria, and Chalmers University of Technology, Sweden.
The study is available here.
