Numerical Simulation Research on Precooling Characteristics of LNG Discharge Pipeline

Abstract

The low-temperature fluid flowing into the LNG unloading pipeline will cause violent heat exchange phenomenon, resulting in damage to the pipeline and affecting normal operation. Therefore, pre-cooling treatment is required in advance. Considering the fluid-solid heat transfer and fluid flow characteristics comprehensively, multi-physics coupling simulation study on the pre-cooling problem of the LNG discharge pipe with a π-shaped elbow is carried out. The analysis from BOG and LNG pre-cooling processes respectively shows that: the fluid with low temperature and high density is mainly concentrated at the bottom of the pipe and outside the bend, the wall temperature has a sudden drop at the bend, and there is a large temperature difference between the gas side and the liquid sidewall surface. Mixed convection heat exchange mainly occurs in the tube. There will be a small area of natural convection-dominated heat exchange state in the elbow and the downstream pipe section.