Heat Transfer Enhancement in Condensers in Steam Turbine Based Combined Heat and Power Plants

DOI : http://dx.doi.org/10.13005/bbra/2241

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Today one major challenge is the enhancement of heat transfer in condensers of modern steam-turbine plants. If one shifts from traditional film condensation to dropwise condensation, the heat transfer coefficient on the steam side of the condenser’s tubes significantly increases thanks to the hydrophobization of the external surfaces of the condenser’s tubes. The results of laboratory tests and tests in situ, which have been conducted earlier, provide evidence that hydrophobization of those brass tubes that have been supplied with rather smooth surfaces, with the use of a surface-active film-forming agent belonging to the aliphatic amines class allows to increase the condenser’s heat transfer coefficient by half or even more. This work is devoted to enhancement of heat transfer in condensers of steam-turbine plants through the use of a superhydrophobic effect with preparation at the first stage of a hierarchical double rough structure on brass surfaces with the use of the method of alternating current electrochemical etching in the phosphoric acid. It has been shown for the first time that modern technologies for achieving superhydrophobicity based on treatment of brass surfaces with octadecylamine, a surfaceactive film-forming agent belonging to the aliphatic amines class acting as a hydrophobizer, allows to achieve contact angles at the level of 150°.

Condensers of steam-turbine plants; Heat transfer; Corrosion; Cycle efficiency; Heat transfer coefficient; Hydrophobization; Superhydrophobic effect and Surface-active agent