Industrial water boiler feed water - Water and Wastewater - Water Treatment
Ion exchange is an effective, versatile means of conditioning boiler feedwater. The term “ion exchange` describes the process : as water flows through a bed of ion exchange material, undesirable ions are removed and replaced with less objectionable ones. For example, in softening processes, calcium and magnesium ions(hardness) are exchanged for sodium ions. In dealkalization, the ions contributing to alkalinity(carbonate, bicarbonate, etc.) are removed and replaced with chloride ions.
- Other dealkalization processes utilizing weak acid cation resin or strong acid cation resin in a split stream process, exchange cations with hydrogen.
- This forms carbonic acid which can be removed in a decarbonator tower.
- Demineralisation is simply replacing all cations with hydrogen ions(H+) and all anions with hydroxide ions(OH-).
- Ion exchange materials are like storage batteries; they must be recharged(regenerated) periodically to restore their exchange capacity.
- With proper design and operation, ion exchange processes are capable of removing selected ions almost completely(in some cases to a fraction of a part per million).