Abstract: Aiming at the condensation problem of roof cold nozzles of large LNG storage tanks, this paper takes the top feeding pipe of prestressed concrete fullcapacity LNG storage tanks as an example and carries out the research work. It puts forward a local temperature field analysis model of roof cold nozzles and a method for judging the probability of local condensation of cold nozzles under meteorological conditions at the construction site of storage tanks. The analysis model is adopted to study a series of parameters that may affect the condensation of cold nozzles. The results show that the higher the temperature and humidity of the construction site, the easier the condensation on the surface of the roof cold nozzles. It can reduce the condensation probability effectively to increase the atmospheric convective heat transfer coefficient in a certain range and increase the length of the contact between the cold insulation casing and the atmospheric environment.

Key words: LNG storage tank, cold nozzle, temperature field analysis, condensation, judgment method