Liquid (or Water) hammer or hydraulic transient in Liquefied Natural Gas (LNG) pipelines refers to pressure spikes due to flow changes caused by valve closures and/or pump trips. These actions may cause liquid column separation and rejoining which may result in high surge pressures and dynamic loads. A sudden rise in pressure can cause severe damages to the system or even human loss in some cases. It is very important to protect the system from excessive hydraulic transient pressure by understanding the possible scenarios causing this phenomenon. In this study, some scenarios which can cause hydraulic transient responses in an LNG Ship-loading system are studied and then a mitigation strategy is proposed to reduce liquid hammer in the system by controlling downstream delivery pressure in the ship lines. The hydraulic transient events in the system were simulated using software based on the Method of Characteristics (MOC). Results show that the pressure and dynamic loads are significantly improved by throttling the ship intake valves such that the steady state pressure at the ship flange stays at a recommended level. This mitigation strategy can be applied for similar cases in LNG loading systems.

The Influence of Initial Pressure Distribution on Pressure Transients in LNG Pipes

Created in 1999, the Environmental & Water Resources Institute (EWRI) is the recognized leader within ASCE for the integration of technical expertise and public policy in the planning, design, construction, and operation of environmentally sound and sustainable infrastructure impacting air, land and water resources.

[Paper Proceedings](https://doi.org/10.1061/9780784483466)

Conference DOI: https://doi.org/10.26226/m.6329c39b68fb0e00131f77d2