Condensate Polishing is a process deployed to remove contaminants from condensate stream before it is returned to the boiler/heat exchangers. It is highly important to remove traces of soluble impurities present in feed water, as they may get concentrated within the system.
Ion exchange resins used in condensate polishers mainly serve two purposes:
- Removal of suspended solids by filtration
- Removal dissolved solids by ion exchange
mixed bed resins and strong acid cation exchange resins are used globally in deep bed condensate polishing systems.
Mix Bed Resin
This is a proportionate mixture of strong acid cation exchange resin in H+ form and strong base anion exchange resin in OH form. This type of system is used in high-pressure boilers.
Strong Acid Cation and Mixed Bed Resin
Feed water is passed through strong acid cation in H+ form followed by mixed bed resin. This type of system is used in low to medium pressure boilers.
Strong Acid Cation Exchange Resin
Strong acid cation in Na+ form is used. This type of system is used in low to medium pressure boilers.
The treated water/condensate quality of conductivity 0.1 Mho/cm, Silica less than 20 ppb and pH 6.8 to 7.2 is achievable.