Exergetic Design and Optimisation of LNG Cold Energy Utilisation System for Dual-Fuel Main Engine of a Container Ship

In this paper, a 9200 TEU container LNG fuel-powered ship is used as a prototype ship, and combined with the cooling load requirements of on-board cold storage, desalination and air conditioning, an LNG cold energy cascade comprehensive utilisation system scheme is proposed. On the basis of system simulation analysis, the initial plan is optimised in terms of system process arrangement and power cycle working medium selection, and two optimised design system plans are determined. Based on the genetic algorithm, the global parameter optimisation of the determined scheme is further carried out, and the annual net income and the initial investment cost of the two optimisation design system schemes are analysed. The results showed that the optimised exergy efficiency of the LNG cold energy full power utilisation system proposed in this paper reaches 54.69%, which has the best cold energy utilisation efficiency; and the optimised LNG cold energy cascade comprehensive utilisation system scheme has the optimised exergy efficiency at 50.13%, but it has the best economic benefits.