Power plants use deionized water as makeup to high pressure boilers, for producing steam to drive turbines and generate electricity. The conventional means of purifying boiler feed water has been to use chemically regenerated ion-exchange deionization. This is a widely accepted technology that has been in use for over half a century but has the disadvantage of requiring the use of hazardous chemicals for regeneration of the ion exchange resins.
In addition to describing the recent advances in electrodeionization technology, this paper will discuss some of the process design issues applicable to the use of RO/CEDI systems for reliable production of feed water for high-pressure boilers.