FLUID-GAP MULTI-EFFECT MEMBRANE DISTILLATION PROCESS AND DEVICE THEREOF

摘要

A fluid-gap multi-effect membrane distillation device and method. The device comprises: multiple stages of membrane distillation assemblies, multiple stages of heat exchange assemblies, a heat pump (30) and a connecting pipeline. The tube passes or shell passes between the multiple stages of membrane distillation assemblies and the multiple stages of heat exchange assemblies are alternately and orderly connected through pipes into a raw water flow path. A hot end outlet of the heat pump (30) and the shell passes or tube passes of the multiple stages of heat exchange assemblies are orderly and serially connected through pipes into a hot fluid flow path. The last-stage heat exchange assembly is connected to a hot end inlet of the heat pump (30) through a pipe. A cold end outlet of the heat pump (30) and the shell passes or tube passes of the multiple stages of membrane distillation assemblies are orderly and serially connected through pipes into a cold fluid flow path. The last-stage membrane distillation assembly is connected to a cold end inlet of the heat pump (30) through a pipe. The first-stage membrane distillation assembly (28) is provided with a concentrated water outlet. An inlet of a raw water pipe (21) is connected to a raw water source. An outlet of the raw water pipe (21) is connected to the tube pass or shell pass of the first-stage heat exchange assembly (22) through a pipe. The raw water flows through the tube passes or shell passes of the multiple stages of heat exchange assemblies and the tube passes or shell passes of the multiple stages of membrane distillation assemblies orderly and alternately through pipes, the membrane distillation concentrated water (A) is drained from a concentrated water outlet, and the membrane distillation produced water (B) is drained from a produced water outlet provided on a connecting pipe (32) between the cold end outlet of the heat pump (30) and the first-stage membrane distillation assembly (28).