25000 tons of liquefied natural gas (LNG) powered chemical tanker was studied. After analysis of the original ship exhaust gas system and high temperature cooling water system

considering the residual heat resources of the original ship and the unused LNG cold energy

combinations such as exhaust power turbine

LNG cold energy generation ORC

freezing water desalination

high and low temperature cold storage and air-conditioning systems were installed to meet the demand of power generation

desalination

cold storage and air-conditioning in this ship. Also

five kinds of energy system cascade utilization schemes of LNG cold energy were put forward. Through the simulation calculation and comparative analysis of software HYSYS

aspects of exergy efficiency and economy of each scheme were evaluated. The result showed that low temperature cold storage + high temperature cold storage + air conditioning system was the best in economy and exergy efficiency. The exergy efficiency of new system can be improved to 62.87% after optimization. At the same time

the annual economic income can reach 12.2785 million CNY.