Research on re-liquefaction of cargo BOG using liquid ammonia cold energy on CO2 transport ship

Aiming at the problems of large power consumption in the CO2 BOG re-liquefaction process and waste of marine fuel cold energy on very environmentally friendly ammonia-powered CO2 transport ships, a system that uses liquid ammonia cold energy for CO2 BOG re-liquefaction process is designed. Using the simulation software Aspen HYSYS to establish the process flow and simulate the system, comparison between simulation results and power consumption of common BOG reliquefaction technology, it is found that the system can save up to 43.30 % of the power consumption. The calculation model of system cold energy utilization efficiency and system exergy efficiency was established and the results were summarized. The results show that the maximum cold energy utilization efficiency of liquid ammonia is 77.50 %; the maximum system exergy efficiency is 73.95 %, which can realize the efficient utilization of the liquid ammonia cold energy. The economics of the system on the whole route of the typical ship are calculated and analyzed, use this system can greatly reduce the power consumption and fuel consumption of refrigeration during the CO2 BOG re-liquefaction process, and has good economic benefits.