Plate heat exchanger used in cooperation with marine large-temperature-difference cold seawater unit

The invention relates to a plate heat exchanger used in cooperation with a marine large-temperature-difference cold seawater unit, in particular to the technical field of refrigeration equipment, and the plate heat exchanger comprises a seawater channel system composed of a warm water inlet T1 and a cold water outlet T2, and a refrigerant system composed of a refrigerant inlet S1 and a refrigerant outlet S2. Refrigerant in the plate heat exchanger is of a double-flow flowing type and comprises a flooded liquid supply layer and a dry liquid supply layer, the flooded liquid supply layer accounts for 2/3 of the whole refrigerant double-flow flowing type, and the dry liquid supply layer accounts for 1/3 of the whole refrigerant double-flow flowing type. The plate heat exchanger has the advantages of being high in heat exchange efficiency, small in heat loss, compact in structure, small in occupied area, convenient to install and clean, wide in application, long in service life and the like, under the condition of