Abstract: Aiming at the condensation problem of cold nozzles on top of large LNG storage tanks, this paper takes the top feeding pipe of pre-stressed concrete full-capacity LNG storage tanks as an example. And it carried out a quantitative analysis of the five main factors influencing local condensation of cold nozzles by adopting a L16(45) orthogonal analysis method. The results show that the influence order of the five factors from the largest to the smallest are length of the insulating sleeve without outside insulation, atmospheric convective heat transfer coefficient, inner insulation thickness, the tempreture of atmospheric environment and length of the insulating sleeve. It can reduce the condensation probability effectively to increase length of the insulating sleeve without outside insulation, atmospheric convective heat transfer coefficient and inner insulation thickness in a certain range. And the larger the diameter of the cold nozzle is, the higher the condensation probability will be.

Key words: LNG storage tank, cold nozzle, orthogonal analysis, condensation analysis, influencing factors