The invention discloses a multi-effect
membrane distillation seawater desalination system based on mechanical compression. The multi-effect
membrane distillation seawater desalination system based on the mechanical compression comprises a plurality of serially-connected vacuum
membrane distillation assemblies and heat exchange assemblies, a plurality of serially-connected concentrated water flash
distillation tanks, a plurality of serially-connected
fresh water flash
distillation tanks, a mechanical steam compressor and a vacuumizing
system, wherein the serially-connected vacuum membrane
distillation assemblies and the heat exchange assemblies form multi-effect distillation in the conventional distillation sense; the serially-connected concentrated water flash distillation tanks receive concentrated
seawater after membrane distillation and perform stage-by-stage flash distillation, and flash distillation steam is used as heating steam corresponding to each-effect material liquids; the serially-connected
fresh water flash distillation tanks receive
fresh water produced during the membrane distillation and perform stage-by-stage flash distillation, and flash distillation steam is used as heating steam corresponding to each-effect material liquids; the mechanical steam compressor raises the temperature and the pressure of secondary steam produced by the last-effect membrane distillation
assembly through consumption of
electric energy, and provides heating steam for the first-effect heat exchange
assembly. The multi-effect membrane distillation
seawater desalination system based on the mechanical compression couples a multi-effect membrane distillation process and a multi-stage flash distillation process, pumps the last-effect secondary steam through the mechanical steam compressor, and recycles the last-effect secondary steam after quality improvement to achieve gradient utilization of energy and two-way concentration of the material liquid, so that consumption of cooling water is not required, the heat efficiency is high, the water making ratio is high, the concentrating ratio is high, and the adaptability is high.