The freezing desalination method is not being used widely

since it needs refrigeration system that consumes much electricity power.On the other hand

liquefied natural gas(LNG)will release a lot of cold energy during its vaporization process.Thus

combining the two processes of LNG vaporization and seawater freezing will produce freshwater while gasifying LNG.In this paper

two kinds of seawater freezing desalination methods are compared

which are the secondary refrigerant/seawater direct-contact method and the secondary refrigerant/seawater indirect-contact method.The indirect-contacting method is then chosen for further study because it is simple and easy to be applied.Two processes are presented with different refrigerant conditions.In the non-phase-change process

the secondary refrigerant remains as subcooled liquid in the whole cycle.In the phase-change process

the secondary refrigerant is vaporized when freezing the seawater

and is condensed when gasifying the LNG.Performances of the two systems at different refrigerating temperatures are analyzed.The study shows that the phase-change process has smaller refrigerant mass flow rate and power consumption.The results show that it is practical to achieve seawater desalination by recovery of LNG cold energy.