CO2 capture and liquefaction in a novel zero carbon emission co-production scheme for ships by integration of supercritical CO2-based oxy-fuel cycle and ion transport membrane; Energy/exergy/exergoeconomic/exergoenvironmental (4E) and multi-objective optimization

Abstract

The main goal of this research in the first step is to present a new power generation and cooling system with zero emissions for ships. The presented system is a combination of oxygen separator membrane, Oxy-fuel cycle, lithium bromide-water (LiBr-H2O) double-effect absorption refrigeration cycle, and carbon dioxide (CO2) liquefaction cycle. The fuel of the system is liquefied natural gas(LNG). In the second step, the presented system is evaluated from energy, exergy, exergy-economic and environmental exergy viewpoints. In the third step, multi-objective optimization is used to pinpoint the optimal state of the presented scheme based on economic, performance, and environmental impacts (EI). The results revealed that in the reference state the energetic efficiency is 95% and exergetic efficiency is 38%. The net power per kilogram of produced oxygen and liquefied carbon dioxide is equal to 1194 kW and 47.42 kW, respectively. The levelized cost per exergy unit (LCPEU) of the gross power of the supercritical CO2 (SCO2) cycle turbine, nitrogen turbine, the produced cold water, and total products (cooling and power) are equal to 26.75 $/GJ, 270 $/GJ, and 63.05 $/GJ, respectively. The multi-objective optimization outcomes demonstrated that the exergetic efficiency of the system and the cost per exergy unit (CPEU) of all products can be improved up to 18 % and 13 %, respectively. Moreover, the environmental impact per exergy unit (EIPEU) of all products can be improved by up to 6 %.