Seawater desalting method and device

The invention discloses a seawater desalting method and a seawater desalting device. Wind power is used as a working power supply in the method; the heated purified water is fed into a heat storage tank, and heat is circularly supplied by two paths; one path of hot water enters a first effect of a multi-effect distilled seawater desalting device and is used as a seawater desalting heat source, and enters the heat storage tank after heat release; the other path of hot water enters a pre-heater of the first effect of the multi-effect distilled seawater desalting device to a pre-heater of the last effect in turn, and flows back to the heat storage tank after pre-heating the seawater; after the seawater in a first effect evaporation chamber is evaporated in a falling film tube, the obtained thick seawater is led out, and the generated steam enters a second effect falling film tube and is used as a seawater evaporation heat source; the seawater flowing out from the next effect evaporation chamber is heated by the previous pre-heater and then enters the previous effect evaporation chamber; and the condensed steam generated by the last effect evaporation chamber is used as produced fresh water for discharge. The device is suitable for the seawater desalting method, and mainly comprises a solar heat collecting system, a seawater pre-heating system, a multi-effect distilled seawater desalting system and a heat pump system.