Softeners and Ion-Exchangers

Water Softening

Hardness in water is caused by the ions of calcium and magnesium and is of prime concern for many technical applications because of its scale-forming tendencies.
For this reason, some water users on board ship need softened water, e.g. hot water circuits, laundry water, boiler feed water, cooling water...

And some need even more, i.e. a higher degree of demineralisation, than evaporators, reverse osmosis or softeners may provide. This is than achieved by an Ion-Exchanger plant.

For both, softener and demineralisation units, RWO has the right solution:

• skid mounted units in a compact, marine suitable design
• chemical saving processes
• reliable and operations safe equipment
• electronically controls for automatic," hands-off " operation
• all for a very competitive price

Ion-Exchange Softening

The water softening is accomplished by ion exchangers, where the hardness compounds calcium and magnesium are removed and replaced with sodium. If water containing calcium and magnesium is passed trough an ion-exchanger, these are taken up by the resin, which simultaneously gives up sodium in exchange.

Once the ability of the bed to produce soft water has been exhausted, the unit is removed from service and regenerated with a solution of sodium chloride. This removes the calcium and magnesium in the form of their soluble chlorides and at the same time restores the resin to its original sodium condition.

All RWO softening plants are characterized by a chemical and water saving regeneration mode, meaning more softened water with less salt and less waste water.

Design

RWO ion-exchange softeners are of the pressure type with either manual or automatic control. Small water softeners normally consist of a glassfibre reinforced plastic (GRP) vessels, larger units are of steel construction with adequate corrosion protection.

As a standard the systems are designed for fully automatic operation, controlled by either simple and easy to operate electromechanical control units or else by latest state of the art microprocessor or PLC units.

A variety of accessories is available, e.g. sensor control for a quality dependent regeneration triggering, hardness-monitors for continuos hardness measuring and control, and optional upgradings for seawater regeneration to save further chemical and water costs.

Water Demineralisation

A demineralisation plant is also an ion-exchanger system but goes one step further than the softeners by removing basically all dissolved ions from the water. The result is a fully demineralised water, low in conductivity and free of other impurities such as silica and CO₂ - therefore suitable e.g. for ship turbines and other
technical applications that require "pure water ".