PVP2008-61620 DISCUSSION OF ISSUES RELATED TO SURGE IN LNG PIPELINES AT OFFLOADING TERMINALS

Due to requirements of LNG unloading terminals, the pipelines used to transport the liquid operate near the vapor pressure of the LNG. If the operational pressure in the pipeline falls below the vapor pressure, pockets of gas will develop; when these pockets collapse, very high pressure pulses can be transmitted through the pipeline, an event known as surge or waterhammer. This paper discusses transients that occur during normal and upset plant operation and how these transients can induce surge in the pipeline. The paper concludes with an overview of the methods used to evaluate whether surge will occur and the peak pressure associated with surge events, with an overview of cases that are typical candidates for analysis