Heat transfer enhancement in steam-turbine condensers with the use of surface-active substances

Abstract

A technology of the enhancement of the power efficiency of steam-turbine plants (STPs) is proposed by the treatment of surfaces of a piped condenser system over the steam and water sides with the use of surface-active substances (SAS). The transition of filmwise condensation into dropwise makes it possible to increase the heat-transfer coefficient by 50–70% because of hydrophobization of outside surfaces of the steam side that results in vacuum extension at minimum operating costs. The resulting data are verified by laboratory investigations and full-scale tests. The accumulation rate of thermobarrier deposits over the water side decreases by a factor of 6–8, and, correspondingly, the overhaul life connected with the refinement of condenser pipes increases. The maintenance of the hydrophobic film of SAS at the outside surface of condenser pipes can be provided by the periodic injection of SAS on the inlet of a low-pressure cylinder (CLP) of the turbine both in the period of short-time stops and during the operation of STPs. At the same time, because of the additional dispersion of the liquid phase, the rate of drop-impact erosion of the blade row decreases by 30%.