A primary objective in the successful operation of any steam generating system is to maximize its overall efficiency and reliability while minimizing problems related to water and steam quality. One of the greatest factors in achieving this objective is the amount and quality of condensate returned to the boiler as feedwater. Returned condensate, being condensed steam, is extremely free of impurities and has a relatively high heat content, making it ideal, both economically and technically, for boiler feedwater.

Economically, the more condensate returned, the less make-up water required; thereby, saving on both water and feedwater pretreatment costs. The high purity of condensate allows the boiler to operate at higher cycles of concentration while maintaining conductivity standards; thereby, reducing costly water and energy losses to boiler blowdown. The higher heat content of condensate as compared to make-up water directly reduces the fuel requirements of the boiler to convert feedwater into steam.

Technically, the high purity of condensate reduces the overall scale-forming tendency of boiler feedwater regardless of the sophistication of the make-up water pretreatment system. This results in cleaner heat transfer surfaces and optimal heat transfer rates. Higher quality feedwater reduces the possibility of boiler tube failure due to excessive scaling.

To realize the benefits of a condensate return system, a program of corrosion control must be implemented. Left untreated or treated improperly, condensate can become very corrosive to plant piping and equipment. The resulting products of corrosion can enter the feedwater and form harmful, tenacious deposits on boiler heat transfer surfaces. The lack of condensate corrosion control can ultimately result in the loss of heat transfer efficiency and ruptured boiler tubes, a leading cause of unscheduled plant shutdowns.