Two stage, monopolar and bipolar electrodialysis process achieving reduced energy consumption

摘要

This new method is used for the electrodialysis of fluids, accompanied by water electrolysis. Fluid containing a salt undergoes monopolar electrodialysis. Concentrate flowing from this stage is then subjected to bipolar electrodialysis. A novel feature of this process is that the concentrate stream undergoing bipolar electrodialysis, is mixed with fluid which has been reduced in concentration by bipolar electrodialysis, i.e. resultant dilutate. Also claimed is the equipment to carry out the procedure. This includes monopolar and bipolar electrodialysis units (6, 11), each with one or more electrodialysis stacks, with a circuit (15, 10) for cyclic electrodialysis of the dilutate. The new feature is connection of the concentrate chamber (s) (9) of the monopolar dialysis to the dilutate circuit (15, 10).