The invention discloses a
liquefied natural gas (LNG) cold energy-driving
seawater desalination device and method with double functions of
vaporization and freezing. The operating principle of the device is based on the characteristic that the
phase equilibrium pressure of
water vapor decreases along with the decrease of the temperature, the cold energy of LNG is utilized to realize low temperature and vacuum, the
water vapor on the surface of the
raw material seawater is pumped to promote the
vaporization of
seawater and the endothermal effect of the
vaporization process is utilized to ensure that the
raw material seawater is frozen, i.e.,
fresh water is separated from seawater through the two
phase transition processes of vaporization and freezing. The device mainly comprises a water pump, a filter, a degassing
tower, an air-precooled
heat exchanger, a vaporization-
crystallization device, a crystallizer, a scrubbing separator, a melting device, a
vacuum pump and the like. The deviceis mainly characterized in that LNG cold energy driving is adopted, gas-liquid-
solid separation is performed at the
triple point of seawater, and high-quality
fresh water and sea icy freshwater are obtained; and the device has the advantages of cold energy cascaded utilization, higher energy efficiency, higher
fresh water yield and the like. In addition, an LNG receiving
station is usually built by the sea and has good geopolitical combinability with a
seawater desalination project.