Scope of Application of Electrodialysis Process in Ultrapure Water Equipment

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A comparison of the desalination performance of electrodialysis with other competitive processes yields the following general conclusions:

1. Ion exchange is most advantageous when salt concentrations are very low;

2. Electrodialysis and reverse osmosis are most advantageous when salt concentrations are moderate;

3. Evaporation is most advantageous when salt concentrations are very high.

The table below lists the applicable scope of electrodialysis.

Scope of application	Salt content unit	Salt content variation range		power consumption	Remark
Scope of application	Salt content unit	Water ingress	Out of water	kw.h/m ³	Remark
Seawater desalination	mg/L	25,000-35,000	500-1000	13-25	Suitable for seashores or islands, but due to high power consumption, only medium and small-sized electrodialysis units are used.
Brackish water desalination	mg/L	1000-10000	500-1000	1-5	Suitable for brackish water and coastal areas
Primary desalination of tap water	mg/L	500-1000	10-50	Approximately 1	The preparation of primary pure water to replace distilled water is suitable for use as water in low-pressure boilers.
Desalination of raw water with high hardness	Total hardness: mmol/L Electrical conductivity: μs/cm	3-8 700-1000	0.015–0.031	Approximately 1	Suitable for low-pressure boiler water and chemical analysis water with high water hardness.
Preparation of ultrapure water	Electrical conductivity: μs/cm	10000-17000	0.2–0.3	Approximately 2	Suitable for high-pressure boiler water in power plants and water used in the electronics industry . Methods for preparing high-purity water: 1. Electrodialysis – primary mixed bed – mixed bed; 2. Ion exchange – electrodialysis.