On Cold Energy Power Generation in LNG Ship Comprehensive Utilization of Cold and Heat Scheme

A Ship Comprehensive Utilization of Cold and Heat Scheme for gas turbine driven ships is proposed. The system is composed of a BOG recondensation subsystem, a two-stage Rankine cycle power generation subsystem, an air-conditioner refrigeration subsystem and a combined gas and steam turbine power cycle subsystem. Three versions of power generation schemes with different two-stage generation arrangements are devised and verified by means of HYSYS software. The optimum scheme is selected through entropy analysis. The law of total power generation of the expansion machine against the entropy efficiency of power generation system is studied under the condition of different LNG inlet temperature/evaporation pressure. System economy is analyzed. The analysis proves that the entropy efficient of the system reaches 25.88%, the total power generation 340 kW. Increasing LNG inlet temperature and evaporation pressure can raise system entropy efficiency but the total power generation of the expansion machine will go down.