(179b) Model-Based Comparative Assessment of Onboard Carbon Capture Technologies for LNG-Fueled Ships Using Flue Gas Waste Heat Only

Today there are more than 60,000 large carrier ships in the ocean transporting most of the world products goods. The International Maritime Organization (IMO) has set ambitious greenhouse gas reduction targets for the shipping industry. These ships are built to last more than 30 years. Onboard carbon capture is a transitional solution for the shipping industry to maintain efficient and economical operations over the coming two decades. This study design and evaluates different onboard carbon capture system technologies and assess if they can operate using only the available energy in the flue gas stream without burning extra fuel. The study was carried out for a case study of for an LNG-fueled vessel. Organic Rankine cycles were applied to all the capture systems to satisfy the work requirements of the investigated capture technologies. Four technologies—absorption, membrane separation, temperature swing adsorption, and cryogenic separation—were analyzed for their capture performance. Adsorption showed the highest potential, achieving a 49.0% capture rate, which could reach 65.3% with added cryogenic cooling. Absorption performed well at 45.8%, while membrane and cryogenic separation were less effective, achieving only 21.6% and 29.3% respectively, due to thermal energy limitations onboard. Further studies with real ship data are recommended to refine these results and address operational constraints.