Boiler Blowdown

the removal of impurities from the steamwater path of a boiler unit. Boiler blowdown is classified as either continuous, with an ongoing expulsion of impurities together with boiler water from the upper drum, or periodic, with the insoluble contaminants, or sludge, and some boiler water being removed from the lower collectors of the circulation loop no more than once each shift. The heat of the blow-down water is usually utilized.