How Does an Industrial Water Dealkalizer Work?
Industrial water dealkalizers are important for boiler make-up water among other applications. So how does an industrial water dealkalizer work?
Alkalinity reduction is critical for boiler make-up water treatment because the alkalinity of the water is often the limiting factor in determining the boiler blowdown amount. Proper dealkalization of water allows for cleaner steam production and can significantly lower boiler operating costs because blowdown more reducing the use of fuel and chemical treatment for the boiler.
Industrial water dealkalizers work by utilizing a strong base anion resin for downflow regeneration, coupled with a valve control system. The industrial water dealkalizers regenerate using salt brine – sodium chloride – plus a small amount of caustic – sodium hydroxide – with 10 parts brine for every 1 part caustic. The sodium hydroxide increases the capacity of the make-up water while removing all carbon dioxide from the water to produce an effluent that is neutral. Typically, a dealkalizer regenerates each cubic foot of resin with 0.4-0.5 pounds of caustic plus 4-6 pounds of salt.
In the case of cooling tower makeup and some other situations, a water dealkalizer may be operated without sodium hydroxide, in which case the CO2 is not removed, the effluent is slightly acidic (pH < 7), and the capacity is reduced by about 33%. A dealkalizer operated with sodium hydroxide will remove alkalinity at a rate of approximately 90%.
Industrial water softening is important when using an industrial water dealkalizer, as all water entering the dealkalizer must be softened, otherwise, calcium and magnesium will produce fouling deposits in the resin of the dealkalizer. For this reason, it is necessary that the salt used in regeneration is hardness-free.
An industrial water dealkalizer will remove HCO3-, CO3=, SO4=, NO3-, and CO2, all of which are considered to be total exchangeable anions in the water dealkalizer operation. The water’s total dissolved solids will remain the same although a light silica reduction is common. If needed, more silica can be removed by regenerating the dealkalizer at higher sodium hydroxide levels while increasing the temperature of the regeneration water to ~95°F.
Learn more about how an industrial water dealkalizer works. and use our free online calculator to determine the energy savings for your boiler when you use an industrial water dealkalizer. Contact Nancrede Engineering if you have any questions about industrial water dealkalizers.