Feed water before it is supplied to the steam boiler should be treated first to be suitable water for feeding into steam boiler. One of water treatment is demineralization process. Demineralization process is the process to remove dissolve matter in the form of positive ion and negative ion by treating water with demineralizer.
Demineralizer consists of two exchanger, anion exchanger and cation exchanger. Demineralization process is divided by two steps, in the first step; water is distributed to cation exchanger. Cation exchanger has function to exchange cations of sodium, magnesium and calcium to hydrogen ions. In the second step, water from cation exchanger is distributed again to anion exchanger. Anion exchanger has function to remove anions of silica, carbonate, chloride, and sulfate. The result is output pure water. Demineralizer are generally used in steam boiler or power plant that has high or medium pressure and need high quality of pure water.
Operator of boiler or power plant should maintain demineralizer equipment to prevent condensation on both cation exchanger and anion exchanger. Corrosion will happen to these equipments if constant formation of moisture with acces to air. Corrosion can be prevented with the use of good ventilation in the room containing equipments and coating to be as insulator.
The advantages of using demineralization process are reduce water blowdown in the steam boiler, with pure water can produce high quality of steam, and reduce requirement of make up water.