Ship-based carbon capture onboard of diesel or LNG-fuelled ships

Abstract

Total shipping carbon emissions were approximately 938 million tonnes CO2 in 2012. Zero emission shipping options rely on the use of electricity or alternative fuels, such as blue hydrogen or ammonia. However, that requires major modifications to the ships and the logistics of fuel distribution. As a transition solution, which can be implemented on much shorter term; this study presents the technical and economic evaluation for ship-based carbon capture (SBCC) on diesel or LNG-fuelled vessels. Two reference ship engines of 1280 kW and 3000 kW were chosen. The process is simulated using Aspen Plus®, with 30 wt% aqueous monoethanolamine (MEA) and 30 wt% aqueous piperazine (PZ) as solvents. CAPEX and OPEX were reduced by integrating the thermal energy of the exhaust gas with the stripper reboiler for the diesel and LNG powered ships. For the LNG ships, the cooling capacity from evaporation of LNG was used for liquefying the captured CO2. By using piperazine, which allows CO2 to be desorbed at higher pressure than MEA, the minimal cost of CO2 captured achieved was 98 €/tonne CO2 with a corresponding 1.8 million euros equipment cost for the 3000 kW engine ship. Additionally, the feasibility of SBCC is investigated by adapting an existing cargo ship design (powered by the reference 3000 kW engine) for including the carbon capture process equipment. The capture, compression and storage units are fitted onboard, and the design is modified so that the transport capacity remains the same, while maintaining the ship stability.