Dealkalisers

Dealkalisers utilise weak cation resin to change the bicarbonates (alkalinity) in the water to carbonic acid. To remove the carbonic acid, the water is passed through a degasser tower. When exhausted, the resin is regenerated by acid.

The total dissolved solids (TDS) content of water is reduced by an amount equivalent to the alkalinity present in the raw water and therefore a partially demineralised water is produced. This is very useful as the capital and operating cost of the treatment are very low.

Typical applications are for the pretreatment of boiler feed water where lowering the feed water TDS enables the boiler blowdown to be reduced. Also, dealkalisation by ion exchange is finding widespread acceptance and use in soft drinks and brewing industry. Both of these industries require low alkalinity water for certain products  and dealkalisation by ion exchange is a clean, easily automated, low cost process with many advantages over the more traditional cold lime treatment or direct acid injection methods.

AWE have two ranges of dealkalisers  similar to the range of base exchange softeners. The small 'packaged plant' range utilises special vinyl ester pressure vessels and all plastic multiport valves. The large industrial range features specially lined mild steel pressure vessels, individually lined valves and pipework and microprocessor control. Automatic regeneration is normally intiated by a pH controller.