Dynamic simulation study on the relieving process of the safety valve in supercritical LNG pipeline

In this paper, the limitation of the traditional method to determine the relieving rate of supercritical fluid had been expounded based on a case study of real specified LNG terminal. Furthermore, a dynamic model on the relieving scenario of the LNG pipe safety valves had been developed by a process simulation software HYSYS Dynamic. The rationality of the orifice area required in safety valve could be validated by the model under the hydraulic expansion and fire scenarios. In addition, the main variables including pressure, temperature and relieving rate could be identified in respond to the time. The study clearly showed that the established dynamic model could simulate the real relieving process of the safety valve in the LNG pipeline, verify the designed orifice area in safety valve could satisfy the requirements, and provide a comparatively reasonable method for the model selection of the pressure valve.