Techno-economic and efficiency analysis of adsorption systems for onboard carbon capture in the marine vessels

Onboard Carbon Capture and Storage (OCCS) technologies present an innovative opportunity for marine vessels to meet the International Maritime Organization's (IMO) decarbonization goals. However, the techno-economic feasibility of these technologies remains a critical concern. This study presents a comprehensive and realistic techno-economic analysis of adsorption systems for onboard carbon capture on medium-range tankers operating with Heavy Fuel Oil (HFO) or Liquefied Natural Gas (LNG). Two advanced adsorption configurations, Vacuum Swing Adsorption (VSA) and Temperature Swing Adsorption (TSA), were evaluated using performance benchmarks from state-of-the-art land-based models, adapted to maritime conditions. Results indicate that moisture management in flue gas, high thermal demand for dehydration, and limited adsorbent tolerance to water are the key technical challenges. TSA systems integrated with LNG-fueled vessels can provide superior performance due to effective utilization of waste heat and cryogenic infrastructure, achieving a $320/t CO₂ avoidance cost. In contrast, VSA systems exhibit higher electrical demands and lower net decarbonization benefits, especially in HFO scenarios. While at medium-range tanker scale, adsorption exhibits lower capture costs than membranes and cryogenics, it remains less economic than mature amine absorption systems. For the TSA-HFO configuration, a waste-heat-constrained analysis shows that limiting operation to available waste heat reduces the capture rate to ∼33% but eliminates auxiliary boiler firing and lowers the Cost of CO₂ Avoided by 29%, demonstrating that the techno-economic optimum does not necessarily coincide with the maximum capture rate. A system-boundary sensitivity analysis further confirms that the configuration ranking is robust to the recursive inclusion of parasitic emissions.