Performance of a novel waste heat-powered ionic liquid-based CO2 capture and liquefaction system for large-scale shipping

•A novel waste heat-powered ionic liquid-based CO2 capture and liquefaction system for large-scale shipping is proposed.•Multiple cycles and modules significantly reduce the net energy consumption of the system.•The effect of 10 important operational parameters on the system performance was investigated.•The optimal working condition was obtained through multi-parameter optimization.•The minimum net energy consumption is 0.467 GJ/tCO2, which was 57.29% lower compared to the normal system. In this work, we proposed a novel CO2 capture and liquefaction system for large-scale shipping using ionic liquid as capture solvent. By utilizing the waste heat of the exhaust gas and jacket cooling water from the ship’s engine as well as the residual pressure energy of the N2-O2 mixture from the CO2 absorption and desorption process, the system’s net energy consumption has been significantly reduced. We established the thermodynamic model of the system and investigated the effect of 10 primary system operational parameters on system performance with 3 different ionic liquids as CO2 capture solvent. The results demonstrated that the system with [DEME][TF2N] as the CO2 capture solvent had the best system performance. In addition, we performed a multi-parameter optimization of the system using simulated annealing algorithm with net energy consumption as the optimization objective and the minimal net energy consumption is 0.467 GJ/tCO2. Compared to the CO2 capture system that do not utilize waste heat and residual pressure energy, the net energy consumption was reduced by 57.29 % under optimal operational conditions which proves that the novel system significantly reduces the energy consumption of the CO2 capture and liquefaction process.