Exergy, energy, economy analysis and multi-objective optimization of a comprehensive energy utilization system for LNG-powered ships based on zero-carbon emissions

Abstract

To realize efficient utilization of energy in LNG-powered ships and zero-carbon emissions, a comprehensive energy utilization system based on zero-carbon emissions for LNG-powered ships is proposed in this study coupling the full utilization of LNG cold energy and flue gas waste heat with the carbon capture technology of oxygen-enriched combustion with the LNG dual-fuel-powered bulk carrier as the object as well. By system modeling, the system is analyzed using the thermoeconomic method and the operating parameters are studied. The results demonstrate the selection of the working fluid combinations and the settings of the operating parameters of equipment affect the system's thermodynamic and economic performance. Based on the parameters analysis, a multi-objective genetic algorithm is adopted for optimization. The optimization results indicate that 51.71 % exergy efficiency and 511 kW net output power are achieved under the zero-carbon emissions condition, while the initial investment cost and cost of power generation are 6.33·106$ and 0.0869$/kWh, which indicate the system is of excellent environmental and economic benefits.