The importance of the boiler feedtank, where boiler feedwater and make-up water are stored and into which condensate is returned, is often underestimated. Most items of plant in the boiler house are duplicated, but it is rare to have two feedtanks and this crucial item is often the last to be considered in the design process.
The feedtank is the major meeting place for cold make-up water and condensate return. It is best if both of these, together with flash steam from the blowdown system, flow through sparge pipes installed well below the water surface in the feedwater tank. The sparge pipes must be made from stainless steel and be adequately supported.