Preliminary Study and Review of Oxy-fuel Combustion with Cryogenic Onboard CO2 Capture for LNG-Driven Ships

The maritime industry faces growing pressure to reduce greenhouse gas emissions in line with the International Maritime Organization’s 2030 and 2050 decarbonization targets. This study proposes a novel onboard CO2 capture solution for LNG-powered ships, integrating oxy-fuel combustion with a Turbo-Expander-based Cryogenic Distillation Technology (CryoDT). By increasing CO2 partial pressure through oxy-fuel combustion and utilizing cold energy from onboard LNG and low-purity oxygen or Crude Liquid Oxygen (CLOX) from a simplified Air Separation Unit (ASU), the system eliminates solid CO2 formation and external utility requirements. A hybrid approach incorporating process simulations using Aspen HYSYS and P-HENS was developed to generate several feasible heat exchanger networks. Among the generated networks, a compact, low-cost design that minimizes Total Annualized Cost (TAC) from utility energy consumption and heat transfer area was selected for its spatial and operational advantages. Results indicate that with 80 mol.% oxygen purity, a 35 % reduction in energy penalty and a capture efficiency of 92 % can be achieved. This integrated approach offers a highly compact, energy-efficient and practical pathway for onboard CO2 capture, tailored to maritime constraints.