On increasing the efficiency of condensing heat exchangers of thermal power plants by changing the wettability of heat exchange surfaces

One of the promising directions for improving the efficiency of condensing heat exchangers is the intensification of heat transfer through the transition from the traditional film mode to the dropwise condensation mode, in which condensate is formed as separate droplets rather than a continuous film, which virtually eliminates thermal resistance in the form of a condensate film. As a result, heat exchange processes are intensified during condensation of water vapor. In this paper, experimental studies were conducted to determine the effect of modifying heat exchange surfaces on the efficiency of a condensing heat exchanger. The modification was carried out by forming a film of a surfactant, octadecylamine, on the heat exchange surface, resulting in the hydrophobization of the surface. A laboratory heat exchanger prototype was developed and manufactured for conducting experimental research on the territory of CHPP-16 of the Mosenergo branch of the Federal State Budgetary Educational Institution of Higher Professional Education NRU MEI. Analysis of the research results has shown that modifying heat exchange surfaces using octadecylamine is a technologically sound solution for intensifying heat exchange processes in condensing heat exchangers. As a result of modifying the steel tubes of the laboratory heat exchanger prototype, the contact angle increased from 88° for the original surface to 110°. The transition to the dropwise condensation mode resulted in an increase in the thermal power of the laboratory heat exchanger prototype up to 61.5% compared to the original surface under identical operating conditions.