DUFN™ systems : Technical Details

• Cation Exchange, HCl regeneration  

In this first stage, the exchange of strong cations retains the Ca²⁺, Cr³⁺, Mg²⁺, Na⁺, K⁺ ions in the water that is to be treated and releases the H⁺ ions from the previous regeneration.

• Anion exchange, NaOH regeneration

In this second stage, the exchange of strong anions retains the chromate, silicate, CO₃^2-, HCO₃^-, SO₄^2-, NO₃^- Cl^- SiO₂ ions of the decationised water and releases the OH^- ions from the previous regeneration.

An ion exchange reaction can continue for as long as the resin can provide the H⁺ and OH^- ions from the previous regeneration by replacing the salts of the raw water. When the resin is saturated, it has to be brought back to its initial state through regeneration.

DUFN™ can be provided with 2 types of resins - Type I and Type II.

• Type I gel structure is particularly suited to the production of process steam with good stability at 70°C, and for water production in the pharmaceutical industry (no salting out of amine or ethanol grouping) etc.

• Type II gel structure also adapted to the production of process steam and to water containing little organic matter, has weak resistance at 30°C etc.

Resin regeneration occurs through a slow counterflow (downflow) rinsing.

• Master Control - used to operate one or several DUFN™ units,
• Slave Control - used when DUFN™ are installed in double banks,
• Junction Box - used for operating DUFN™ externally via a host PLC.