Dry heat rejection technology by direct contact heat exchange for waste heat removal system

Abstract

Applying the direct contact heat transfer technology, dry cooled waste heat removal system for the nuclear power plants is designed. The steam after turbine is condensed by a heat exchanger submerged in a non-evaporative fluid pool, thus there is no material exchange between the steam after turbine and environment. The heated fluid is pumped to the spray at high level and emitted into the air and the cooled fluid during passing the air is returned to the fluid pool by gravity. The air circulates in a large cooling tower designed to generate sufficient driving pressure. The fluid is emitted by two different methods, which are direct contact heat transfer on falling droplets and falling films of the fluid, and the designs for increased surface area of the falling fluid and stable operation of the system are introduced and direct contact heat transfer on the falling fluid and pressure loss of the air flow are analyzed. The analysis results show that the falling films system has smaller cooling tower than the falling droplets system due to low falling velocity of the films and low relative velocity of the air, thus the falling films system is considered as competitive alternation of the traditional dry cooling systems.