Based on the high energy consumption of membrane distillation (MD) process and the excessive cooling water consumption issues, a new type of vacuum multiple-effect membrane distillation (MEMD) process was designed. The process set up a special multiple-effect evaporation zone for the first time where heat exchange and MD happened at the same time. The experiment studied the effects of the membrane area in main evaporation zone, feed fluid flow of the lumen side of membrane module and module length of multiple-effect evaporation zone on MEMD process. The equivalent flux of the system can reach the maximal value (34.8 kg•m-2•h-1) and the additional cooling water consumption is only 30.8% of traditional VMD process when the feed inlet temperature of the module and the membrane area in the main evaporation zone are 345 K and 0.10 m2, feed fluid flow is 4.0 L•h-1, and the module length is 868 mm of multiple-effect evaporation zone. The MEMD process has a wonderful industrial application prospect.
